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Sample records for cold rolling evolution

  1. INFLUENCE OF COLD ROLLING TECHNOLOGY ON TEXTURE EVOLUTION OF IF STEEL

    Institute of Scientific and Technical Information of China (English)

    J.X. Li; X.H. Liu; G.D. Wang

    2002-01-01

    Two kinds of cold rolling experiments, single cold rolling and double cold rolling, werecarried out on one titanium stabilized interstitial free (IF) steel that has been warmrolled at ferrite temperature. The main aim was to investigate the evolution of rollingand annealing textures from the well known behavior observed under single cold rollingcondition to the less understood double cold rolling by using orientation distributionfunction (ODF). In the twice cold rolled samples, the annealing texture comprises onlyfirst round of rolling. Accordingly both the once cold rolled sample and the twice coldrolled sample with heavy reduction in the first round of rolling have much complextexture components. They are related to the formation of initial {111} subgrain andthe priority growth of stable {111} nucleus.

  2. Microstructural Evolution in Hot and Cold-Rolled Ti-Nb Alloy

    Science.gov (United States)

    Tabei, A.; Startt, J.; Hoffman, R. T.; Yavari, E.; Deo, C.; Garmestani, H.

    2016-10-01

    Phase transformations, morphology, and crystallographic texture evolution in hot and cold-rolled Ti-25.51 wt.% Nb alloys are investigated. The experimental procedure involves synthesis of the alloy by arc melting followed by cold or hot rolling with intermediate prior and postheat treatments. Composition and phase analysis of all alloys are conducted using x-ray diffraction techniques and microstructural observations are conducted using an optical microscope. These examinations reveal that the as-melted alloy possesses large millimeter size grains with no stored strain energy and a two phase β - α' microstructure. Direct cold rolling followed by a short homogenization leads to a β - α'' mixture with ω precipitates. Two hour annealing before cold rolling leads to an α' - α'' mixture with a characteristic triangular martensitic microstructure evidencing the act of shear on formation of the phase. Hot rolling followed by a water quench results in a β - α'' mixture, while annealing prior to hot rolling transforms the arc-melted material to a α' - α'' mixture. The crystallographic textures of similar microstructure mixtures in hot and cold-rolled samples are distinctively different. The analysis shows that the microstructure serves as an identifying characteristic of the processing paths and is highly dependent on the mode of processing.

  3. Microstructural Evolution in Cold-Rolled Squeeze-Cast SiCw/Al Composites during Annealing

    Institute of Scientific and Technical Information of China (English)

    Wenlong ZHANG; Dezun WANG; Zhongkai YAO; Mingyuan GU

    2004-01-01

    A 15 vol. Pct SiCw/Al composite was fabricated by a squeeze cast route followed by hot extrusion in the extrusion ratio of 18:1 and cold rolling to 50%. Microstructural evolution in the cold rolled composite during annealing was studied using macrohardness measurement and transmission electron microscopy (TEM). It was found that, during cold rolling the plastic flow of the matrix was restricted by the whiskers around them along the rolling direction, which resulted in different microstructure from near whiskers to far away. The cold rolled composite exhibited different microstructural development on 1 h annealing at different temperatures. Under annealing at about 100℃, recovery reaction occurred obviously and the introduction of SiC whiskers resulted in enhanced recovery reaction. Under annealing above about 200℃, recrystallization (growth of nuclei by high-angle grain boundary migration) and extended recovery took place simultaneously. When annealing temperature was increased up to 500℃, recrystallization fully took place in the cold rolled microstructure. The starting temperature of recrystallization was about 200℃. Whiskers played a role in stimulating the nucleation of recrystallization.

  4. Evolutions of Microstructure and Properties During Cold Rolling of 19Cr Duplex Stainless Steel

    Science.gov (United States)

    Ran, Qingxuan; Xu, Wanjian; Wu, Zhaoyu; Li, Jun; Xu, Yulai; Xiao, Xueshan; Hu, Jincheng; Jiang, Laizhu

    2016-10-01

    Evolutions of microstructure, mechanical, and corrosion properties of 19Cr (Fe-18.9Cr-10.1Mn-0.3Ni-0.261N-0.030C-0.5Si) duplex stainless steel have been investigated during cold rolling at room temperature. Dislocation slip dominated deformation mode of ferrite phase. However, deformation mechanism of austenite phase was different with the increasing cold-rolling reductions. Dislocation slip and strengthening effect of twin boundaries caused pile-up phenomenon at the initial deformation stage. When the amount of cold-rolling reduction attained greater than 50 pct, induced α'-martensite appeared in deformed austenite phase. Hardness of austenite phase was higher than that of the deformed ferrite because of its higher strengthening effect during cold-rolling process. Cold-rolling deformation caused deterioration of the pitting corrosion resistance in 3.5 wt pct NaCl aqueous solution. Pitting corrosion always initiated in the ferrite phase and the phase boundary in the solution-treated alloy. Additional pitting holes appeared in deformed austenite phase because of the decrease in corrosion resistance caused by dislocation accumulation and induced α'-martensite.

  5. Statistical analysis on static recrystallization texture evolution in cold-rolled AZ31 magnesium alloy sheet.

    Science.gov (United States)

    Park, Jun-Ho; Ahn, Tae-Hong; Choi, Hyun-Sik; Chung, Jung-Man; Kim, Dong-Ik; Oh, Kyu Hwan; Han, Heung Nam

    2013-08-01

    Cast AZ31B-H24 magnesium alloy, comprising Mg with 3.27 wt% Al and 0.96 wt% Zn, was cold rolled and subsequently annealed. Global texture evolutions in the specimens were observed by X-ray diffractometry after the thermomechanical processing. Image-based microstructure and texture for the deformed, recrystallized, and grown grains were observed by electron backscattered diffractometry. Recrystallized grains could be distinguished from deformed ones by analyzing grain orientation spread. Split basal texture of ca. ±10-15° in the rolling direction was observed in the cold-rolled sample. Recrystallized grains had widely spread basal poles at nucleation stage; strong {0001} basal texture developed with grain growth during annealing.

  6. Microstructure evolution during isochronal annealing of a 42% cold rolled TRIP-TWIP steel

    Science.gov (United States)

    Pramanik, S.; Saleh, A. A.; Santos, D. B.; Pereloma, E. V.; Gazder, A. A.

    2015-08-01

    A high manganese TRIP-TWIP steel was cold rolled to 42% thickness reduction and isochronally annealed between 600 to 900 °C for 300 s. The microstructural evolution during annealing was studied by high resolution electron back-scattering diffraction. After cold rolling, the steel comprised predominant fraction of α'-martensite, a small fraction of blocky ε-martensite and a trace fraction of retained austenite (γ). During annealing, the reversion of ε and α' martensite to γ was followed by the recrystallisation of γ. While the processes of reversion to and recrystallisation of γ were completed by 700 °C, further annealing between 750 to 900 °C led to γ grain growth. A novel method to delineate the γ-γ grain boundaries was developed in order to accurately quantify γ grain size and subsequently the activation energy for γ grain growth.

  7. Deformation behavior of electro-deposited pure Fe and its texture evolution during cold-rolling and subsequent annealing

    Science.gov (United States)

    Sugiura, N.; Yoshinaga, N.; Ushioda, K.

    2015-04-01

    Electro-deposited pure Fe has a characteristic of having very sharp isotropic ND// fiber texture with a needle-like shaped fine grain elongated to ND. This Fe exhibits a surprisingly high r-value of over 7; however, such a high r-value might not be rationalized only from texture. Careful slip analyses reveal that restricted slips take place in the specific {110} slip planes, which are perpendicular to the sheet surface. Since grain boundaries with columnar structure are also perpendicular to the sheet surface, the slip plane in a certain grain may easily connect to the slip plane in adjacent grains having within ±30 degree rotation relationship around the common axis of ND//. The operation of such a slip system is considered to cause the width strain much larger than the thickness strain. Furthermore, the texture evolution during cold-rolling and subsequent annealing was investigated using electro-deposited pure Fe as a starting material. Regardless of the amount of cold-rolling reduction, 65% to 90%, {111} cold-rolling texture developed. After recrystallization, {111} texture remained when material is cold-rolled by 65%, while {111} texture developed when materials are cold-rolled by 80% and 90%. From the investigation into the mechanism on the development of recrystallization texture, the oriented nucleation and selective growth theories are concluded to contribute to the evolution of annealing texture.

  8. Microstructure and texture evolution of cold-rolled deep-drawing steel sheet during annealing

    Science.gov (United States)

    Zhou, Le-yu; Wu, Lei; Liu, Ya-zheng; Cheng, Xiao-jie; Sun, Jin-hong

    2013-06-01

    In accordance with experimental results about the annealing microstructure and texture of cold-rolled deepdrawing sheet based on the compact strip production (CSP) process, a two-dimensional cellular automation simulation model, considering real space and time scale, was established to simulate recrystallization and grain growth during the actual batch annealing process. The simulation results show that pancaked grains form during recrystallization. {111} advantageous texture components become the main parts of the recrystallization texture. After grain growth, the pancaked grains coarsen gradually. The content of {111} advantageous texture components in the annealing texture increases from 55vol% to 65vol%; meanwhile, the contents of {112} and {100} texture components decrease by 4% and 8%, respectively, compared with the recrystallization texture. The simulation results of microstructure and texture evolution are also consistent with the experimental ones, proving the accuracy and usefulness of the model.

  9. Effects of Recrystallization on Microstructure and Texture Evolution of Cold-Rolled Ti-6Al-4V Alloy

    Science.gov (United States)

    Jiang, Haitao; Dong, Peng; Zeng, Shangwu; Wu, Bo

    2016-05-01

    The effects of recrystallization during annealing process on microstructure and texture evolution of cold-rolled Ti-6Al-4V alloy plates were investigated. The plates after cold rolling with a thickness reduction of 5, 10, and 15% were annealed under different conditions of 750 °C for 1 h, 800 °C for 1 h, and 800 °C for 1.5 h, respectively. It was found out that the recrystallization temperature decreased with increasing rolling reduction due to higher storage energy, while the extension of annealing time caused grain growth. For the cold-rolled plate with a reduction of 10%, the resulting microstructure showed more equal-axis grains after annealing at 800 °C for 1 h, among different conditions. Moreover, the XRD results showed that the cold-rolled plate composed mainly of {0001} basal texture, {10-11} and {01-12} pyramidal textures, and {01-10} prismatic texture, and that the weak {10-11} texture was transformed to components {01-12} and {01-10} , which were expected to improve formability. Electron back-scattered diffraction results ascertained that two mechanisms, i.e., recrystallization sites of preferred orientations and favorable grain growth both played important roles in static recrystallization.

  10. Textural and microstructural evolution during cold-rolling of pure nickel

    DEFF Research Database (Denmark)

    Hansen, Niels; Juul Jensen, Dorte; Hughes, D.A.

    1994-01-01

    High purity nickel (99.99%) with a grain size about 100 μm has deformed by cold-rolling from 37% to 98% reductions. The deformation microstructures and the crystallographic texture have been characterised using transmission electron microscopy and neutron diffraction, respectively. The microstruc......High purity nickel (99.99%) with a grain size about 100 μm has deformed by cold-rolling from 37% to 98% reductions. The deformation microstructures and the crystallographic texture have been characterised using transmission electron microscopy and neutron diffraction, respectively...

  11. Microstructure and texture evolution of the cold-rolled AZ91 magnesium alloy strip under electropulsing treatment

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Yanbin, E-mail: jyb05@mails.tsinghua.edu.cn [Key Laboratory for Advanced Materials Processing (MOE), University of Science and Technology Beijing, Beijing 100083 (China); Tang Guoyi, E-mail: tanggy@mail.tsinghua.edu.cn [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Shek, Chanhung [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong (Hong Kong); Liu Wei [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2011-03-17

    Research highlights: > EPT induced recrystallization of cold-rolled AZ91 strip, and suppressed the precipitation of {beta}-Mg{sub 17}Al{sub 12} phase in the (-Mg matrix, at a relatively low temperature within a short time of 7 s. > The extent of EPT induced recrystallization increased gradually with frequency, and the recrystallized grains favourably weakened the intensity of the basal texture until the full recrystallization was achieved. > Compared with conventional heat treatment, EPT tremendously accelerated recrystallization process of the cold-rolled AZ91 due to the substantial increase in the atomic flux resulted from the coupling of the thermal and athermal effects. - Abstract: The effect of electropulsing treatment (EPT) on the microstructure and texture evolution of the cold-rolled AZ91 magnesium alloy strip was investigated using X-ray diffraction (XRD) and electron backscattered diffraction patterns (EBSD). The results indicated that EPT accelerated tremendously the recrystallization behaviour of the cold-rolled AZ91 magnesium alloy strip at a relatively low temperature within a short time of 7 s. It also suppressed precipitation of {beta}-Mg{sub 17}Al{sub 12} phase, compared with conventional heat treatment. The recrystallized grains favourably weakened the intensity of the basal texture. A mechanism for rapid recrystallization process during EPT was proposed based on the enhancement of nucleation rate and atomic diffusion resulting from the coupling of the thermal and athermal effects.

  12. Effect of Change in Strain Path During Cold Rolling on the Evolution of Microstructure and Texture in Al and Al-2.5%Mg

    Science.gov (United States)

    Bhattacharjee, P. P.; Saha, S.; Gatti, J. R.

    2013-11-01

    The effect of change in strain path during cold rolling on the evolution of microstructure and texture is investigated. For this purpose, high purity aluminum and Al-2.5%Mg alloy are deformed ( 90% reduction in thickness) by unidirectional and cross cold rolling. Irrespective of the alloy system, copper-type texture is observed in unidirectional processed materials, while strong brass ({011}) texture is developed during cross rolling. Unidirectionally rolled aluminum showed higher HAGB fraction, but similar HAGB spacing as compared to the cross-rolled aluminum after 90% reduction in thickness. At the same time, the internal misorientation in the cross-rolled 2N-Al is higher than in the unidirectionally rolled material. In contrast, Al-2.5% Mg alloy processed differently in both ways shows similar HAGB fraction, spacing, and internal misorientation distribution. These observations indicate that microstructure evolution due to strain path change is more strongly affected by dynamic recovery as compared to texture evolution.

  13. Microstructural evolution in warm-rolled and cold-rolled strip cast 6.5 wt% Si steel thin sheets and its influence on magnetic properties

    Science.gov (United States)

    Wang, Xianglong; Liu, Zhenyu; Li, Haoze; Wang, Guodong

    2017-07-01

    6.5 wt% Si steel thin sheets were usually fabricated by warm rolling. In our previous work, 6.5 wt% Si steel thin sheets with good magnetic properties had been successfully fabricated by cold rolling based on strip casting. In the present work, the main purposes were to find out the influences of warm rolling and cold rolling on microstructures and magnetic properties of the thin sheets with the thickness of 0.2 mm, and to confirm which rolling method was more suitable for fabricating 6.5 wt% Si steel thin sheets. The results showed that the cold rolled sheet could obtain good surface quality and flatness, while the warm rolled sheet could not. The intensity of γ-fiber rolling texture (//ND) of cold rolled specimen was weaker than that of the warm rolled specimen, especially for the {1 1 1} component at surface layer and {1 1 1} component at center layer. After the same annealing treatment, the cold rolled specimen, which had higher stored energy and weaker intensity of γ-fiber rolling texture, could obtain smaller recrystallization grain size, weaker intensity of γ-fiber recrystallization texture and stronger intensity of λ-fiber recrystallization texture. Therefore, due to the good surface quality, smaller recrystallization grain size and optimum recrystallization texture, the cold rolled specimen possessed improved magnetic properties, and cold rolling should be more suitable for fabricating 6.5 wt% Si steel thin sheets.

  14. Evolution of orientations and deformation structures within individual grains in cold rolled columnar grained nickel

    DEFF Research Database (Denmark)

    Wu, G.L.; Godfrey, A.; Winther, Grethe;

    2011-01-01

    Columnar grained Ni is used as a model material allowing simultaneous non-surface investigations of the evolution of crystallographic orientations and deformation microstructures within individual grains as a function of rolling strain up to ε=0.7. Electron channelling contrast and electron...

  15. Effects of electric field on recrystallization texture evolution in cold-rolled high-purity aluminum sheet during annealing

    Institute of Scientific and Technical Information of China (English)

    WU Yan; ZHAO Xiang; HE Chang-shu; ZHAO Zhi-peng; ZUO Liang; C. ESLING

    2007-01-01

    The effects of an external DC (direct current) electric field on recrystallization texture evolution in the cold-rolled aluminum sheets with 99.99% purity were investigated by means of X-ray diffraction techniques. The cold-rolled high-purity aluminum sheets were annealed for 60 min at 200, 300 and 400 ℃, respectively with and without an external DC electric field of 800 V/mm. The results show that with DC electric field, the recrystallization cube texture is strengthened at the stage of grain growth. Possible reason for the strengthening of the recrystallization cube texture with the applied electric field may be attributed to both selected nucleation and selected growth of cube oriented crystal nuclei.

  16. Effect of the Heat-treatment Temperature on the Mechanical Properties and Microstructural Evolution of Cold-rolled Twinning-induced Plasticity Steel

    Institute of Scientific and Technical Information of China (English)

    LI Dazhao; WEI Yinghui; SONG Jinlu; HOU Lifeng

    2015-01-01

    TWIP steels with 70%cold-rolled reduction were heated at 500, 600, 700, 800, 900, 1000, and 1100℃. Then, the properties before and after heating were examined through tensile and hardness experiments. The microstructures were also analyzed by optical microscopy and transmission electron microscopy. The relationship between the properties and microstructure was examined as well. Finally, the evolution process of cold-rolled microstructures during heating was discussed in detail. Moreover, some conclusions can be drawn, and the heating evolution characteristics are described.

  17. High-speed steel rolls used for cold rolling

    Institute of Scientific and Technical Information of China (English)

    QU Haixia; WU Qiong; SUN Dale

    2015-01-01

    During cold rolled production of steel,each change of rolls causes a halt in production and affects the roll’s grinding maintenance and consumption.Consequently,rolls are very critical to the costs of steel production. Besides the rolling accidents,surface quality problems,including inhomogeneous wear and a decrease of the surface roughness of the rolls are other main reasons for outage and a change of the rolls.Therefore,safe rolls,with superior wear resistance and roughness retentivity will be a future trend in the cold rolling steel industry.In this study,the property characteristics and in-service performance of high-speed steel(HSS)cold rolling work rolls at Baosteel are discussed.The results of this study indicate that in-service performance of HSS cold work rolls has an improvement over conventional rolls.Implementation of HSS work rolls will prolong the rolling campaign and improve the rolling stability,thus,the cost of cold rolling production can be better controlled.

  18. EFFECTS OF MAGNETIC FIELD STRENGTH ON MICROSTRUCTURE AND TEXTURE EVOLUTION IN COLD-ROLLED INTERSTITIAL-FREE STEEL BY MAGNETIC FIELD ANNEALING

    Institute of Scientific and Technical Information of China (English)

    Y. Wu; C.S. He; X. Zhao; L. Zuo; T. Watanabe

    2008-01-01

    Effects of magnetic field strength on the evolution of recrystallization microstructure and recrystallization texture in cold-rolled interstitial-free steel were investigated after annealing at 660°C in a magnetic field up to 12 T. Magnetic annealing was found to retard recrystallization and induce recrystallized grains elongated along the magnetic field direction. An interesting phenomenon is that the magnetic field shows the strongest effect at 1 T.

  19. Microstructure and texture evolution of ultra-thin grain-oriented silicon steel sheet fabricated using strip casting and three-stage cold rolling method

    Science.gov (United States)

    Song, Hong-Yu; Liu, Hai-Tao; Wang, Yin-Ping; Wang, Guo-Dong

    2017-03-01

    A 0.1 mm-thick grain-oriented silicon steel sheet was successfully produced using strip casting and three-stage cold rolling method. The microstructure, texture and inhibitor evolution during the processing was briefly analyzed. It was found that Goss texture was absent in the hot rolled sheet because of the lack of shear deformation. After normalizing, a large number of dispersed MnS precipitates with the size range of 15-90 nm were produced. During first cold rolling, dense shear bands were generated in the deformed ferrite grains, resulting in the intense Goss texture after first intermediate annealing. The microstructure was further refined and homogenized during the subsequent cold rolling and annealing processes. After primary recrystallization annealing, a homogeneous microstructure consisting of fine and equiaxed grains was produced while the associated texture was characterized by a strong γ-fiber texture. Finally, a complete secondary recrystallization microstructure consisting of entirely large Goss grains was produced. The magnetic induction B8 and iron loss P10/400 was 1.79 T and 6.9 W/kg, respectively.

  20. Microstructural Evolution during Isothermal Annealing of a Cold-Rolled Al-Mn-Fe-Si Alloy with Different Microchemistry States

    OpenAIRE

    Huang, Ke; Li, Yan Jun; Marthinsen, Knut

    2014-01-01

    In this paper, investigation of the softening behaviour of a supersaturated Al-Mn-Fe-Si alloy during annealing after cold rolling has been carried out. Two different homogenization conditions were considered, of which one gives a condition of a large amount of small pre-existing dispersoids, i.e. providing a significant static Zener drag, while the other gives a condition where both concurrent precipitation and dispersoid drag effects are limited. The homogenized samples with different microc...

  1. Research on work roll thermal crown in cold rolling mill

    Science.gov (United States)

    Song, Lei; Shen, Mingang; Chen, Xuebo; Wang, Junsheng

    2013-05-01

    The factors which have influence on the work roll thermal crown in cold strip rolling are discussed. The heat transferring in three directions (radial axis and circumference) were considered for calculating the work roll thermal deformation. Therefore, it is a three dimensions unstable system for the work roll temperature calculation. The plastic deformation work and friction heat are calculated by the divided element and digital integration method. The simplified calculation model is built for the heat transferring along work roll. There are four zones for work roll heat transferring: roll gap zone air cooling zone emulsion zone rolls contact zone. The heat transferring between the zones is decided by the temperature difference. The inter temperature field and thermal deformation of work roll can be calculated by two-dimension finite difference method. The work roll temperature and thermal crown of actual application cold rolling mill are analyzed by the model. By the comparison between calculated values and measured values, the work roll thermal calculation model can meet the accuracy requirement of on-line control.

  2. Lubrication in strip cold rolling process

    Institute of Scientific and Technical Information of China (English)

    Jianlin Sun; Yonglin Kang; Tianguo Xiao; Jianze Wang

    2004-01-01

    A lubrication model was developed for explaining how to form an oil film in the deformation zone, predicting the film thickness and determining the characteristics of lubrication in the strip rolling process, combined with the knowledge of hydrodythicknesses in the strip cold rolling. Results from the experiment and calculation show that the oil film forming in hydrodynamic lubrication is up to the bit angle and a higher rolling speed or a higher rolling oil viscosity. The mechanism of mechanical entrainment always affects the film thickness that increases with the rolling oil viscosity increasing or the reduction rate decreasing in rolling.

  3. Role of Friction in Cold Ring Rolling

    Institute of Scientific and Technical Information of China (English)

    He YANG; Lianggang GUO; Mei ZHAN

    2005-01-01

    Cold ring rolling is an advanced but complex metal forming process under coupled effects with multi-factors, such as geometry sizes of rolls and ring blank, material, forming process parameters and friction, etc. Among these factors,friction between rolls and ring blank plays animportant role in keeping the stable forming of cold ring rolling. An analytical method was firstly presented for proximately determining the critical friction coefficient of stable forming and then a method was proposed to determine thecritical friction coefficient by combining analytical method with numerical simulation. And the influence of friction coefficient on the quality of end-plane and side spread of ring,rolling force, rolling moment and metal flow characteristic in the cold ring rolling process have been explored using the three dimensional (3D) numerical simulation based on the elastic-plastic dynamic finite element method (FEM)under the ABAQUS software environment, and the results show that increasing the friction on the contact surfaces between rolls and ring blank is useful not only for improving the stability of cold ring rolling but also for improving the geometry and dimension precision of deformed ring.

  4. Rolling Force and Rolling Moment in Spline Cold Rolling Using Slip-line Field Method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dawei; LI Yongtang; FU Jianhua; ZHENG Quangang

    2009-01-01

    Rolling force and rolling moment are prime process parameter of external spline cold rolling. However, the precise theoretical formulae of rolling force and rolling moment are still very fewer, and the determination of them depends on experience. In the present study, the mathematical models of rolling force and rolling moment are established based on stress field theory of slip-line. And the isotropic hardening is used to improve the yield criterion. Based on MATLAB program language environment, calculation program is developed according to mathematical models established. The rolling force and rolling moment could be predicted quickly via the calculation program, and then the reliability of the models is validated by FEM. Within the range of module of spline m=0.5-1.5 mm, pressure angle of reference circle α=30.0°-45.0°, and number of spline teeth Z=19-54, the rolling force and rolling moment in rolling process (finishing rolling is excluded) are researched by means of virtualizing orthogonal experiment design. The results of the present study indicate that:the influences of module and number of spline teeth on the maximum rolling force and rolling moment in the process are remarkable;in the case of pressure angle of reference circle is little, module of spline is great, and number of spline teeth is little, the peak value of rolling force in rolling process may appear in the midst of the process;the peak value of rolling moment in rolling process appears in the midst of the process, and then oscillator weaken to a stable value. The results of the present study may provide guidelines for the determination of power of the motor and the design of hydraulic system of special machine, and provide basis for the farther researches on the precise forming process of external spline cold rolling.

  5. Evolution of Microstructure and Texture during Annealing of Aluminum AA1050 Cold Rolled to High and Ultrahigh Strains

    DEFF Research Database (Denmark)

    Mishin, Oleg; Juul Jensen, Dorte; Hansen, Niels

    2010-01-01

    orientation: the mean size of grains having orientations of the rolling texture was smaller than the size of grains with other orientations. The orientation dependence of the recrystallized grain size was more pronounced in the samples rolled to ultrahigh strains. © 2010 The Minerals, Metals & Materials...

  6. The effect of roll gap geometry on microstructure in cold-rolled aluminum

    DEFF Research Database (Denmark)

    Mishin, Oleg; Bay, B.; Winther, G.

    2004-01-01

    Microstructure and texture are analyzed through the thickness of two aluminum plates cold-rolled 40% with different roll gap geometries. It is found that both texture and microstructure are strongly affected by the rolling geometry. After rolling with intermediate-size draughts a rolling-type tex......Microstructure and texture are analyzed through the thickness of two aluminum plates cold-rolled 40% with different roll gap geometries. It is found that both texture and microstructure are strongly affected by the rolling geometry. After rolling with intermediate-size draughts a rolling...

  7. Positron annihilation and transmission electron microscopy study of the evolution of microstructure in cold-rolled and nitrided FeNiTi foils

    NARCIS (Netherlands)

    Chechenin, N.G.; Veen, A. van; Escobar Galindo, R.; Schut, H.; Chezan, A.R.; Bronsveld, P.M.; Hosson, J.Th.M. de; Boerma, D.O.

    2001-01-01

    Positron beam analysis (PBA) and transmission electron microscopy (TEM) were applied to study structural transformations in cold-rolled Fe0.94Ni0.04Ti0.02 foils, which were subjected to different thermal treatments in an atmosphere of a gas mixture of NH3 + H2 (nitriding). Positrons proved to be sen

  8. Cold rolling precision forming of shaft parts theory and technologies

    CERN Document Server

    Song, Jianli; Li, Yongtang

    2017-01-01

    This book presents in detail the theory, processes and equipment involved in cold rolling precision forming technologies, focusing on spline and thread shaft parts. The main topics discussed include the status quo of research on cold rolling precision forming technologies; the design and calculation of process parameters; the numerical simulation of cold rolling forming processes; and the equipment used in cold rolling forming. The mechanism of cold rolling forming is extremely complex, and research on the processes, theory and mechanical analysis of spline cold rolling forming has remained very limited to date. In practice, the forming processes and production methods used are mainly chosen on the basis of individual experience. As such, there is a marked lack of both systematic, theory-based guidelines, and of specialized books covering theoretical analysis, numerical simulation, experiments and equipment used in spline cold rolling forming processes – all key points that are included in this book and ill...

  9. Automatic Flatness Control of Cold Rolling Mill

    Science.gov (United States)

    Anbe, Yoshiharu; Sekiguchi, Kunio

    One of the subjects of cold rolling is a flatness of the rolled strip. Conventionally, measured strip flatness was approximated by polynomial (2th, 4th, 6th) equation across the entire strip width. This made it difficult to deal with desired loose edge or any desired flatness across the entire strip width. Also conventional flatness control was done for the entire strip width, so if there is a different flatness error among drive side and work side, conventional flatness control can not control properly. We propose independent strip flatness control among drive side and work side, and also automatic flatness control (AFC) system with arbitrary desired strip flatness. Also some applied results to cold mill are shown.

  10. Mechanical performance and texture characteristic of an IF steel containing Nb and Ti by double cold rolling

    Institute of Scientific and Technical Information of China (English)

    Ling-yun Wang; Peng Zhang; Wei Li; Guang-jie Huang

    2009-01-01

    Single cold rolling and double cold rolling were applied to hot rolled strips with different reduction ratios.The evolutions of { 100},{ 111 } and Goss face texture during double rolling were investigated by comparing the orientation distribution function (ODF) of the double rolled sample with that of the single rolled one.The double cold rolling texture is characterized by a higher T-texture and a lower a-texture,and the { 111 } component is improved remarkably.Based on the TEM observation and me-chanical properties test,it is found that the reduction ratio assignment significantly affects the texture variation,as-annealing micro-structures,and properties of the double cold rolled samples.These results may provide a theoretical guide for the industrial produc-tion of double cold rolled IF steel.

  11. Positron annihilation and transmission electron microscopy study of the evolution of microstructure in cold-rolled and nitrided FeNiTi foils

    Energy Technology Data Exchange (ETDEWEB)

    Chechenin, N.G.; Chezan, A.R.; Boerma, D.O. [Nuclear Solid State Physics Laboratory, Materials Science Centre, University of Groningen, Groningen (Netherlands); Veen, A. van; Escobar Galindo, R.; Schut, H. [Interfaculty Reactor Institute, Delft University of Technology, Delft (Netherlands); Bronsveld, P.M.; Hosson, J.Th.M. de [Department of Applied Physics, Materials Science Centre, University of Groningen, Groningen (Netherlands)

    2001-07-02

    Positron beam analysis (PBA) and transmission electron microscopy (TEM) were applied to study structural transformations in cold-rolled Fe{sub 0.94}Ni{sub 0.04}Ti{sub 0.02} foils, which were subjected to different thermal treatments in an atmosphere of a gas mixture of NH{sub 3}+H{sub 2} (nitriding). Positrons proved to be sensitive probes for the microstructure evolution and formation of nitride precipitates. The nitriding of the samples in the {alpha}-region ({alpha}N) of the Lehrer diagram for the Fe-N system produced a large decrease of the central part of the Doppler broadened annihilation {gamma}-peak (S-parameter) and an increase of the contribution to the wings of the peak (W-parameter). The effect, ascribed to replacing of vacancy type positron traps by nitride-related traps, was much more pronounced for the {alpha}-nitrided samples than for samples annealed in vacuum at the same temperature. A reduction of the {alpha}N samples by annealing in H{sub 2} atmosphere brings the S-parameter back to a higher value. Further nitriding of {alpha}N samples in the {gamma}'-region ({alpha}N+{gamma}'N) of the Lehrer diagram increases S and lowers the W-parameter compared with the {alpha}N samples. The changes in S- and W-parameters are interpreted on the basis of the evolution of microstructure of the films during the processing. (author)

  12. FEM Analysis of Rolling Pressure Along Strip Width in Cold Rolling Process

    Institute of Scientific and Technical Information of China (English)

    LIU Xiang-hua; SHI Xu; LI Shan-qing; XU Jian-yong; WANG Guo-dong

    2007-01-01

    Using 3-D elastic-plastic FEM, the cold strip rolling process in a 4-high mill was simulated. The elastic deformation of rolls, the plastic deformation of the strip, and the pressure between the work roll and the backup roll were taken into account. The distribution of rolling pressure along the strip width was obtained. Based on the simulation results, the peak value of rolling pressure and the location of the peak were analyzed under different rolling conditions. The effects of the roll bending force and the strip width on the distribution of rolling pressure along the width direction were determined.

  13. Prediction of Rolling Force Using AN Adaptive Neural Network Model during Cold Rolling of Thin Strip

    Science.gov (United States)

    Xie, H. B.; Jiang, Z. Y.; Tieu, A. K.; Liu, X. H.; Wang, G. D.

    Customers for cold rolled strip products expect the good flatness and surface finish, consistent metallurgical properties and accurate strip thickness. These requirements demand accurate prediction model for rolling parameters. This paper presents a set-up optimization system developed to predict the rolling force during cold strip rolling. As the rolling force has the very nonlinear and time-varying characteristics, conventional methods with simple mathematical models and a coarse learning scheme are not sufficient to achieve a good prediction for rolling force. In this work, all the factors that influence the rolling force are analyzed. A hybrid mathematical roll force model and an adaptive neural network have been improved by adjusting the adaptive learning algorithm. A good agreement between the calculated results and measured values verifies that the approach is applicable in the prediction of rolling force during cold rolling of thin strips, and the developed model is efficient and stable.

  14. Roll Gap Crown Adjustment Characteristics of 1700 mm Cold Rolling Mills

    Institute of Scientific and Technical Information of China (English)

    GUO Jian-bin

    2014-01-01

    The 4-hi cold mill is one of the key wide strip tandem cold rolling mills and has many advantages and characteristics. The mill type is the most important, fundamental and long-term effective factor for the strip shape control. Many advanced mill types such as CVC-4, HCW and PC-4, etc are created based on the conventional four-roll mill. The factors of mill type which affect the deformation of roll system, such as strip width, rolling force, bending force, work roll diameter, backup diameter and so on, are studied how to affect roll gap crown. It provides a good foundation for improving the shape performance of mill.

  15. Nucleation at hardness indentations in cold rolled Al

    DEFF Research Database (Denmark)

    Xu, C.L.; Zhang, Yubin; Wu, G.L.

    2015-01-01

    Nucleation of recrystallization near hardness indentations has been investigated in slightly cold rolled high purity aluminium. Samples were cold rolled to 12% and 20% reductions in thickness and indentations were done with two different loads (500 g and 2000 g). The samples were annealed at 300 ...... and stored energy distributions and thus on nucleation are discussed....

  16. Progress in cold roll bonding of metals

    Energy Technology Data Exchange (ETDEWEB)

    Li Long; Nagai, Kotobu; Yin Fuxing [Innovative Materials Engineering Laboratory, National Institute for Materials Science, Tsukuba 305-0047 (Japan)], E-mail: LI.Long@nims.go.jp

    2008-04-01

    Layered composite materials have become an increasingly interesting topic in industrial development. Cold roll bonding (CRB), as a solid phase method of bonding same or different metals by rolling at room temperature, has been widely used in manufacturing large layered composite sheets and foils. In this paper, we provide a brief overview of a technology using layered composite materials produced by CRB and discuss the suitability of this technology in the fabrication of layered composite materials. The effects of process parameters on bonding, mainly including process and surface preparation conditions, have been analyzed. Bonding between two sheets can be realized when deformation reduction reaches a threshold value. However, it is essential to remove surface contamination layers to produce a satisfactory bond in CRB. It has been suggested that the degreasing and then scratch brushing of surfaces create a strong bonding between the layers. Bonding mechanisms, in which the film theory is expressed as the major mechanism in CRB, as well as bonding theoretical models, have also been reviewed. It has also been showed that it is easy for fcc structure metals to bond compared with bcc and hcp structure metals. In addition, hardness on bonding same metals plays an important part in CRB. Applications of composites produced by CRB in industrial fields are briefly reviewed and possible developments of CRB in the future are also described. Corrections were made to the abstract and conclusion of this article on 18 June 2008. The corrected electronic version is identical to the print version. (topical review)

  17. A new transducer for roll gap measurements of the roll pressure distribution and the friction condition in cold flat rolling

    DEFF Research Database (Denmark)

    Lagergren, Jonas; Wanheim, Tarras; Presz, W.

    2005-01-01

    . Conclusions The new transducer works very well, it was seen to be robust and able to avoid signal disturbance. The pressure and friction stress distribution results was as expected by the authors and a good reproducibility, together with a proven agreement between recorded signals and signals simulated....... Keywords Friction stress, normal pressure distribution, roll bite measurements, cold flat rolling of metals......Background/purpose The only way to establish the true rolling pressure and the true friction condition in cold rolling is to conduct measurements in the roll bite. A new transducer design is therefore proposed, this to overcome problems in previous measurements in the past 70 years. Method The new...

  18. Numerical simulation of involutes spline shaft in cold rolling forming

    Institute of Scientific and Technical Information of China (English)

    王志奎; 张庆

    2008-01-01

    Design of forming dies and whole process of simulation of cold rolling involutes spline can be realized by using of CAD software of PRO-E and CAE software of DEFORM-3D. Software DEFORM-3D provides an automatic and optimized remeshing function, especially for the large deformation. In order to use this function sufficiently, simulation of cold rolling involutes spline can be implemented indirectly. The relationship between die and workpiece, forming force and characteristic of deformation in the forming process of cold rolling involutes spline are analyzed and researched. Meanwhile, reliable proofs for the design of dies and deforming equipment are provided.

  19. Dimensional ranges and rolling efficiency in a tandem cold rolling mill

    Energy Technology Data Exchange (ETDEWEB)

    Larkiola, J.

    1997-12-31

    In this work, physical models and a neural network theory have been combined in order to predict the properties of a steel strip and to optimise the process parameters in cold rolling. The prediction of the deformation resistance of the material and the friction parameter is based on the physical model presented by Bland, Ford and Ellis and artificial neural network computing (ANN). The accuracy of these models has been tested and proved by using a large amount of the measured data. With the aid of these models it has been shown that (a) the small change to the relative reduction distribution can have a clear effect upon the rolling efficiency, (b) the dimensional ranges of the tandem cold roll mill can be determined and optimised and (c) the possibility to cold roll a new product of new width, strength or thickness can be determined and the parameters of the tandem cold rolling process can be optimised. (orig.) 43 refs.

  20. Recrystallization behavior of cold-rolled Zr–1Nb alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Hang [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Western Energy Material Technologies Co., Ltd., Xi’an 710016 (China); Wang, Xitao; Gong, Weijia [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Zhou, Jun [Western Energy Material Technologies Co., Ltd., Xi’an 710016 (China); Zhang, Hailong, E-mail: hlzhang@ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-01-15

    Highlights: • The recrystallization behavior of cold-rolled Zr–1Nb alloy is investigated. • The times required to complete recrystallization of Zr–1Nb alloy are obtained. • The apparent activation energies for recrystallization of Zr–1Nb alloy are derived. • The recrystallization maps for the Zr–1Nb sheets are provided. - Abstract: The recrystallization behavior of cold-rolled Zr–1Nb alloy was investigated by measuring the micro-Vickers hardness of the specimens annealed for various times. Different deformation reductions and annealing temperatures were coupled to study the effects of deformation and temperature on the recrystallization behavior of Zr–1Nb alloy. The results show that both large deformation reduction and high annealing temperature accelerate the recrystallization process. The microstructural evolution during recrystallization was characterized by optical microscope (OM) and transmission electron microscope (TEM) to correlate with the variation of Vickers hardness. The TEM observation also revealed the distribution of different types of Nb-containing precipitates during recrystallization. The Vickers hardness data were fitted by using the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation to derive the activation energies for recrystallization, giving the corresponding recrystallization maps. This study provides useful guidelines for the processing of a broad family of zirconium alloys based on Zr–1Nb.

  1. Effect of sizes of forming rolls on cold ring rolling by 3D-FE numerical simulation

    Institute of Scientific and Technical Information of China (English)

    GUO Liang-gang; YANG He

    2006-01-01

    During cold ring rolling process,changing the sizes of forming rolls including driver roll and idle roll will lead to a change of amount of feed △h and contact areas between ring blank and forming rolls,thus a change of the shape and dimension of deformation zone located in the gap of forming rolls is found. It has a significant effect on metal flow and the forming quality of deformed ring. So the size effect of forming rolls on cold ring rolling was investigated by three-dimensional dynamic explicit FEM under ABAQUS environment. The obtained results thoroughly reveal the influence laws of the sizes of forming rolls on the average spread,fishtail coefficient,degree of inhomogeneous deformation and force and power parameters etc not only provide an important basis for design of the forming rolls and optimization of cold ring rolling process,but also reveal the plastic deformation mechanism of cold ring rolling.

  2. Fracture Behavior of Cold Sprayed 304 Stainless Steel Coating During Cold Rolling

    Institute of Scientific and Technical Information of China (English)

    MENG Xian-ming; ZHANG Jun-bao; HAN Wei; ZHAO Jie

    2012-01-01

    The fracture behavior of cold sprayed 304 stainless steel coating in cold rolling process was studied. The 304 stainless steel coatings were deposited on low carbon steel substrate by cold gas dynamic spray (CGDS) and then cold rolled, respectively. The fracture morphology of the coatings was observed and analyzed, and the crack distri- butions along the longitudinal rolling direction of the coatings were also investigated and discussed. The results showed that the cohesive strength of the cold sprayed 304 stainless steel coating was too low to be cold rolled. Mi crocracks were formed in the as-sprayed coatings and ran perpendicularly to the rolling direction. The spacing dis- tance between these cracks decreased with the increase of the cold rolling reduction. In addition, it was also found that the initial crack generated at the surface of the coating and propagated from the surface to the interface along the weakly bonded particles. A theoretical analysis was developed for the coating fracture. It gave a critical minimum cohesive bonding strength of the coating for non-breaking in cold rolling process. The crack propagation manner of the cold rolled coatings was also discussed.

  3. Research of cold-rolling oil for stainless sheet steel

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The research & application of cold rolling oil for stainless sheet steel are introduced inthis paper. The results indicate that this oil has well properties of anti-wear, oxidation, emulsifyingand fine rust-preventing characteristics, it can meet the employable demands of SENDZIMIR highspeed rolling mill at all.

  4. Annealing textures of severely cold and warm-rolled Al–2.5 wt.%Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gatti, J.R.; Bhattacharjee, P.P., E-mail: pinakib@iith.ac.in

    2014-12-05

    Highlights: • Annealing textures of severely cold and warm-rolled Al–2.5%Mg are reported. • Combination of ARB and conventional rolling is applied for severe deformation. • Pure metal type texture in both cold and warm-rolled conditions. • Stronger cube texture after annealing in warm-rolled than cold-rolled material. • Preferential nucleation of cube grains during annealing in warm-rolled material. - Abstract: The evolution of recrystallization texture was investigated in severely deformed Al–2.5 wt.%Mg alloy. For this purpose the alloy was cold and warm-rolled to 97% reduction in thickness at room temperature and 473 K (200 °C), respectively, using a combination of accumulative roll bonding and conventional rolling. The deformed materials were annealed at temperatures ranging between 473 K (200 °C) and 673 K (400 °C). The deformed materials showed fine lamellar structure and strong copper type texture. However, the warm-rolled material showed much stronger cube texture ({1 0 0}〈0 0 1〉) after different annealing treatments. Orientations of early recrystallized grains in partially recrystallized materials obtained after annealing for short duration revealed strong tendency for preferential nucleation of cube grains in warm-rolled as compared to the cold-rolled material. The observed preferential nucleation of cube oriented grains in warm-rolled material was attributed to more recovered structure of cube oriented grains. In contrast, strong pinning of dislocations by solute Mg atoms during cold-rolling at room temperature inhibited the recovery of cube grains and greatly diminished their preferential nucleation. The cube component was significantly strengthened with increasing annealing temperature in both cold and warm-rolled materials due to the growth of the cube grains.

  5. Recent developments in semiprocessed cold rolled magnetic lamination steel

    Science.gov (United States)

    Hilinski, E. J.

    2006-09-01

    Over the past 10 years the magnetic property performance of semi-processed cold rolled magnetic lamination steels in North America have approached those of nonoriented, semi-processed silicon steel. This improvement was accomplished via higher alloy levels in conjunction with hot band annealing. New temper rolling strategies can produce weakly oriented steels tailored to specific applications, such as small transformers used in fluorescent lighting ballasts. Recently, production trials for 0.0138 in product cold rolled on tin mills has been undertaken. Efforts to further improve properties through a better understanding of texture control and via implementation of new production processes, such as thin slab or strip casting, continue.

  6. COLD ROLLING ORTHODONTIC WIRES OF AUSTENITIC STAINLESS STEEL AISI 304

    Directory of Open Access Journals (Sweden)

    Rodrigo Santos Messner

    2013-03-01

    Full Text Available Austenitic stainless steels wires are widely used in the final stages of orthodontic treatment. The objective of this paper is to study the process of conformation of rectangular wires from round wires commercial austenitic stainless steel AISI 304 by the process of cold rolling. The wire quality is evaluated by means of dimensional analysis, microhardness measurements, tensile strength and fractographic analysis of the wires subjected to tensile tests. Also a study on the application of finite element method to simulate the process, comparing the force and rolling stress obtained in the rolling is done. The simulation results are consistent with those obtained in the actual process and the rolled wires show ductile fracture, tensile strength and dimensional variations appropriate to orthodontic standards. The fracture morphology shows the model cup-cone type besides the high deformation and hardness inherent in the cold rolling process.

  7. Backup roll contour of a SmartCrown tandem cold rolling mill

    Institute of Scientific and Technical Information of China (English)

    Guanghui Yang; Jianguo Cao; Jie Zhang; Shenghui Jia; Renwei Tan

    2008-01-01

    SmartCrown was a new system developed by VAI for improving the strip profile and flatness control first applied in 1700mm tandem cold rolling mills at Wuhan Iron & Steel (Group) Corporation (WISCO). After tracing and testing, the application of the conventional crown backup roll matching the SmartCrown work roll of the production mill led to heavy and nonuniform wear, and the edge spalling of the backup roll often occurred. A 3-dimension finite element model of roll stacks was established, which was used to analyze the above-mentioned problems, and it was found that the main reason was the highly nonuniform contact pressure distribution between the work roll and the backup roll. A new FSR (flexible shape backup roll) was developed and applied in 1700mm tandem cold rolling mills. A lot of good actual effects of FSR, such as evident improvement in profile and flatness of strips,non-occurring edge spalling, wear uniform, and remarkable decrease in roll consumption were validated by long-term industrial applications.

  8. Evolution of defect structures during cold rolling of ultrafine-grained Cu and Cu-Zn alloys: Influence of stacking fault energy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y.H. [Materials Physics and Applications Division, Los Alamos National Laboratory, MS G755, Los Alamos, NM 87545 (United States); Horita, Z. [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); Langdon, T.G. [Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089-1453 (United States); Mork Family, Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Zhu, Y.T. [Materials Physics and Applications Division, Los Alamos National Laboratory, MS G755, Los Alamos, NM 87545 (United States)], E-mail: yzhu@lanl.gov

    2008-02-15

    Samples of pure Cu, bronze (Cu-10 wt.% Zn) and brass (Cu-30 wt.% Zn) with stacking fault energies (SFE) of 78, 35, and 14 mJ/m{sup 2}, respectively, were processed by high-pressure torsion (HPT) and by a combination of HPT followed by cold-rolling (CR). X-ray diffraction measurements indicate that a decrease in SFE leads both to a decrease in crystallite size and to increases in microstrain, dislocation and twin densities for the HPT and HPT + CR processed ultrafine-grained (UFG) samples. Compared with processing by HPT, subsequent processing by CR refines the crystallite size of all samples, increases the twin densities of UFG bronze and brass, and increases the dislocation density in UFG bronze. It also decreases the dislocation density in UFG brass and leads to an unchanged dislocation density in UFG copper. The results suggest there may be an optimum stacking fault energy for dislocation accumulation in UFG Cu-Zn alloys and this has important implications in the production of materials having reasonable strain hardening and good tensile ductility.

  9. Surface quality of cold rolling aluminum strips under lubrication condition

    Institute of Scientific and Technical Information of China (English)

    Jianlin Sun; Wang Lu; Yanli Ma; Qingbing Shi; Aihua Zhang; Jian Li

    2008-01-01

    The effects of oil fill on the rolled surface, including surface roughness and topography, were investigated during cold rolling of aluminum strips. Various mineral oils with viscosities from 0.10 to 1.6 Pa.s were used to obtain different oil film thick-nesses. Results from experiment and calculation show that the thicker oil film protects the initial roughening surface so that it leads to an increase in roughness of the rolled surface, in particular when the surface roughness has the character of direction. The rolled surface roughness was determined by λ, which is the ratio of oil film thickness to the combined surface roughness. When λ > 3, the rolled surface roughness increases rapidly with the increase in oil viscosity, whereas the surface roughening has already occurred when λ < 3, but the increase of the rolled surface roughness with increasing viscosity is not distinct.

  10. Mechanism of electropulsing induced recrystallization in a cold-rolled Mg-9Al-1Zn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Yanbin, E-mail: jiangyanbin@tsinghua.org.cn [Key Laboratory for Advanced Materials Processing (MOE), University of Science and Technology Beijing, Beijing 100083 (China); Tang Guoyi [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Shek Chanhung [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong (Hong Kong); Xie Jianxin [Key Laboratory for Advanced Materials Processing (MOE), University of Science and Technology Beijing, Beijing 100083 (China); Xu Zhuohui [Shenzhen Nonfemet Technology Co., Ltd, Shenzhen 518122 (China); Zhang Zhihao [Key Laboratory for Advanced Materials Processing (MOE), University of Science and Technology Beijing, Beijing 100083 (China)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer EPT tremendously accelerated recrystallization of cold-rolled AZ91 alloy. Black-Right-Pointing-Pointer Microstructure evolution of cold-rolled AZ91 alloy under EPT was studied. Black-Right-Pointing-Pointer Mechanism of EPT-induced recrystallization in cold-rolled AZ91 alloy is discussed. - Abstract: Electropulsing induced recrystallization of a cold-rolled Mg-9Al-1Zn alloy was studied using electron backscattering diffraction pattern (EBSD), transmission electron microscopy (TEM) and hardness test. The results indicated that compared with conventional heat treatment, electropulsing treatment (EPT) substantially accelerated recrystallization of the cold-rolled Mg-9Al-1Zn alloy within a short time of several seconds at relatively low temperature, as well as suppressed precipitation of {beta}-Mg{sub 17}Al{sub 12} phase. Based on the EPT enhanced atomic diffusion resulting from the coupling of the thermal and athermal effects with the direct electron-atom interactions, EPT accelerated recrystallization due to significantly increasing both the velocity of dislocation motion and subgrain growth rate.

  11. Effect of Coiling Temperature on the Evolution of Texture in Ferritic Rolled Ti-IF Steel

    Institute of Scientific and Technical Information of China (English)

    Zhaodong WANG; Yanhui GUO; Wenying XUE; Xianghua LIU; Guodong WANG

    2007-01-01

    The effect of coiling temperatures on the evolution of texture in Ti-IF steel during ferritic hot rolling, cold rolling and annealing was studied. It was found that texture evolution at high temperature coiling is absolutely different from that at low temperature one. The hot band texture includes a strong α-fiber as well as a weak γ-fiber after ferritic hot rolling and Iow temperature coiling. Both of them intensify after cold rolling and a γ-fiber with peak at {111}<112> is the main texture of annealed samples. However, the main component of the hot band texture after high temperature coiling is γ-fiber. After cold rolling, the intensity of γ texture reduces; α fiber (except {111}<110> component) intensifies and a strong and well-proportioned γ-fiber forms in the annealed samples.

  12. Texture analysis of cold rolled and annealed aluminum alloy produced by twin-roll casting

    OpenAIRE

    Juliana de Paula Martins; André Luis Moreira de Carvalho; Angelo Fernando Padilha

    2012-01-01

    A 7.4 mm thick strip of 3003 aluminum alloy produced by the industrial twin-roll casting (TRC) process was homogenized at 500 °C for 12 hours, after which it was cold rolled in two conditions: 1) to reduce the strip's thickness by 67%, and 2) to reduce it by 91%. The alloy was annealed at 400 °C for 1 hour in both conditions. The results revealed that a rotated cube texture, the {001}

  13. Ultrafine Structure and High Strength in Cold-Rolled Martensite

    DEFF Research Database (Denmark)

    Huang, Xiaoxu; Morito, S.; Hansen, Niels

    2012-01-01

    Structural refinement by cold rolling (10 to 80 pct reductions) of interstitial free (IF) steel containing Mn and B has been investigated from samples with different initial structures: (a) lath martensite, (b) coarse ferrite (grain size 150 mu m), and (c) fine ferrite (22 mu m). Unalloyed IF steel...

  14. Adaptive Automatic Gauge Control of a Cold Strip Rolling Process

    Directory of Open Access Journals (Sweden)

    ROMAN, N.

    2010-02-01

    Full Text Available The paper tackles with thickness control structure of the cold rolled strips. This structure is based on the rolls position control of a reversible quarto rolling mill. The main feature of the system proposed in the paper consists in the compensation of the errors introduced by the deficient dynamics of the hydraulic servo-system used for the rolls positioning, by means of a dynamic compensator that approximates the inverse system of the servo-system. Because the servo-system is considered variant over time, an on-line identification of the servo-system and parameter adapting of the compensator are achieved. The results obtained by numerical simulation are presented together with the data taken from real process. These results illustrate the efficiency of the proposed solutions.

  15. Steel strip quality upgrading through optimization of cold rolling schedules in continuous mills

    Institute of Scientific and Technical Information of China (English)

    Garber; E.; Kozhevnikova; I.; Ganichev; P.; Ivoditov; V.; Traino; A.; Kuznetsov; V.

    2005-01-01

    As a result of research into the cold rolling theory and practice, a complex of mathematical models and model-based process solutions has been elaborated to improve quality of cold rolled steel strips and reduce energy consumption. The use of the above designs made it possible to establish a number of new regularities and employ them for cold rolling practice improvement and cold-rolled strip quality upgrading.

  16. Microstructure and texture evolution of AZ31 magnesium alloy during rolling

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The production of magnesium alloy sheets normally involves several processing stages including hot rolling, cold rolling and intermediate annealing. The microstructure and texture evolution of AZ31 magnesium alloy sheets in different processing states were investigated by optical microscopy and X-ray diffraction technique. It is found that the microstructure of hot-rolled sheets is dominated by recrystallized equiaxed grains, while that of cold-rolled sheets is dominated by deformation twins. With final annealing applied on the cold-rolled sheets, fine recrystallization grains are obtained and ductility of the samples is increased. It is also found that the texture of magnesium alloy sheets prefers the basal texture, and other compositions of texture are relatively weak. Moreover,final annealing does not significantly affect texture distribution. The results of this study provide useful guidelines for optimizing the processing of magnesium alloys.

  17. Optimization of cold rolling process parameters in order to increasing rolling speed limited by chatter vibrations.

    Science.gov (United States)

    Heidari, Ali; Forouzan, Mohammad R

    2013-01-01

    Chatter has been recognized as major restriction for the increase in productivity of cold rolling processes, limiting the rolling speed for thin steel strips. It is shown that chatter has close relation with rolling conditions. So the main aim of this paper is to attain the optimum set points of rolling to achieve maximum rolling speed, preventing chatter to occur. Two combination methods were used for optimization. First method is done in four steps: providing a simulation program for chatter analysis, preparing data from simulation program based on central composite design of experiment, developing a statistical model to relate system tendency to chatter and rolling parameters by response surface methodology, and finally optimizing the process by genetic algorithm. Second method has analogous stages. But central composite design of experiment is replaced by Taguchi method and response surface methodology is replaced by neural network method. Also a study on the influence of the rolling parameters on system stability has been carried out. By using these combination methods, new set points were determined and significant improvement achieved in rolling speed.

  18. Improved Fatigue Performance of Threaded Drillstring Connections by Cold Rolling

    Energy Technology Data Exchange (ETDEWEB)

    Kristoffersen, Steinar

    2002-01-01

    The research work presented in this thesis is concerned with analytical, numerical and experimental studies of the effect of cold rolling on the fatigue behaviour of threaded drillstring connections. A comprehensive literature study is made of the various effects on the fatigue behaviour of residual stresses introduced by mechanical deformation of notched components. Some of the effects studied are cyclic hardening behaviour after prestraining, cyclic creep, fatigue initiation in prestrained materials, short cracks and crack growth models including crack closure. Residual stresses were introduced in the surface of a smooth pipe by a rolling device to simulate a cold rolling process and verify the calculated residual stresses by measurements. Strain hardening and contact algorithm of the two bodies were incorporated in the FE analyses. Two significant errors were found in the commercial software package for residual stress evaluation, Restran v. 3.3.2a also called SINT, when using the Schajer method. The Schajer algorithm is the only hole-drilling algorithm without theoretical shortcomings, and is recommended when measuring large residual stress gradients in the depth direction. Using the Schajer method solved by in-house Matlab-routines good agreement between measured residual stress gradients and residual stress gradients from FE analyses was found. Full scale fatigue tests were performed on pipes cut from used drillstrings with notches of similar geometry as threads used in drillstring connections. The simulated threads consisted of four full depth helix notches with runouts at the surface. The pipe threads were cold rolled and fatigue tested in a full-scale four-point rotating bending fatigue testing rig. The test results showed that cold rolling had an effect on the crack initiation period. A major part of the fatigue life was with cracks observed at the notch root, but due to the increased fatigue crack propagation resistance the final fracture initiated at

  19. A new transducer for local load measurements of friction and roll pressure in cold flat rolling

    DEFF Research Database (Denmark)

    Lagergren, J.; Wanheim, Tarras; Precz, W.

    2006-01-01

    The only way to establish the true rolling pressure and the true friction condition in cold rolling is to conduct measurements in the roll bite. A new transducer design is therefore proposed, in order to overcome problems in previous measurements in the past 70 years. The new idea is to increase ...... and able to avoid signal disturbance. The pressure and friction stress distribution results was as expected by the authors and showed good reproducibility, together with a proven agreement between recorded and simulated signals.......The only way to establish the true rolling pressure and the true friction condition in cold rolling is to conduct measurements in the roll bite. A new transducer design is therefore proposed, in order to overcome problems in previous measurements in the past 70 years. The new idea is to increase...... selected from a steady state with no disturbance from the material flow. The transducer was able to simultaneously measure both the normal pressure and the friction stress. An estimation of the coefficient of friction was accordingly performed. The new transducer works very well, it was seen to be robust...

  20. Flatness Control Using Roll Coolant Based on Predicted Flatness Variation in Cold Rolling Mills

    Science.gov (United States)

    Dohmae, Yukihiro; Okamura, Yoshihide

    Flatness control for cold rolling mills is one of the important technologies for improving of product quality and productivity. In particular, poor flatness leads to strip tearing in the extreme case and, moreover, it significantly reduces productivity. Therefore, various flatness control system has been developed. The main actuators for flatness control are classified into two types; one is mechanical equipment such as roll bender, the other is roll coolant, which controls thermal expansion of roll. Flatness variation such as center buckle or edge wave is mainly controlled by mechanical actuator which has high response characteristics. On another front, flatness variation of local zone can be controlled by roll coolant although one's response is lower than the response of mechanical actuator. For accomplishing good flatness accuracy in cold rolling mills, it is important to improve the performance of coolant control moreover. In this paper, a new coolant control method based on flatness variation model is described. In proposed method, the state of coolant spray on or off is selected to minimize the flatness deviation by using predicted flatness variation. The effectiveness of developed system has been demonstrated by application in actual plant.

  1. About texture stability during primary recrystallization of cold-rolled low alloyed zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Gerspach, F. [LETAM, UMR CNRS 7078, Universite Paul Verlaine-Metz (France); Bozzolo, N. [LETAM, UMR CNRS 7078, Universite Paul Verlaine-Metz (France)], E-mail: nathalie.bozzolo@univ-metz.fr; Wagner, F. [LETAM, UMR CNRS 7078, Universite Paul Verlaine-Metz (France)

    2009-02-15

    After cold-rolling along the original hot-rolling direction or the transverse direction, or both alternately, to thickness reduction ratios ranging between 40% and 80%, the texture of low-alloyed zirconium may either be stable or evolve during recrystallization. As a general trend, low strain favors oriented nucleation and therefore texture change, whereas the orientation distribution function is more likely to be stable (i.e. position of the maximum maintained) in highly deformed samples. In addition, a strong deformation texture promotes oriented growth which also influences the texture evolution.

  2. Grain-structure development in heavily cold-rolled alpha-titanium

    Energy Technology Data Exchange (ETDEWEB)

    Dyakonov, G.S. [Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 12 K. Marx Street, 450000 Ufa (Russian Federation); Mironov, S., E-mail: smironov@material.tohoku.ac.jp [Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-aza-Aoba, Sendai 980-8579 (Japan); Zherebtsov, S.V. [Laboratory of Bulk Nanostructured Materials, Belgorod State University, Pobeda 85, Belgorod 308015 (Russian Federation); Malysheva, S.P. [Institute for Metals Superplasticity Problems, Russian Academy of Science, 39 Khalturin Str., Ufa 450001 (Russian Federation); Salishchev, G.A. [Laboratory of Bulk Nanostructured Materials, Belgorod State University, Pobeda 85, Belgorod 308015 (Russian Federation); Salem, A.A. [Materials Resources LLC, Dayton, OH 45402 (United States); Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RXCM, Wright-Patterson AFB, OH 45433-7817 (United States); Semiatin, S.L. [Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RXCM, Wright-Patterson AFB, OH 45433-7817 (United States)

    2014-06-01

    High-resolution electron back-scatter diffraction (EBSD) analysis was employed to establish mircostructure evolution in heavily cold-rolled alpha-titanium. After thickness reductions of 75% to 96%, significant microstructure and texture changes were documented. The surface area of high-angle grain boundaries was almost tripled, thus giving rise to an ultra-fine microstructure with a mean grain size of 0.6 μm. Moreover, orientation spread around typical ‘split-basal’ rolling texture substantially increased. These effects were suggested to be related to the enhancement of pyramidal 〈c+a〉 slip.

  3. Texture analysis of cold rolled and annealed aluminum alloy produced by twin-roll casting

    Directory of Open Access Journals (Sweden)

    Juliana de Paula Martins

    2012-02-01

    Full Text Available A 7.4 mm thick strip of 3003 aluminum alloy produced by the industrial twin-roll casting (TRC process was homogenized at 500 °C for 12 hours, after which it was cold rolled in two conditions: 1 to reduce the strip's thickness by 67%, and 2 to reduce it by 91%. The alloy was annealed at 400 °C for 1 hour in both conditions. The results revealed that a rotated cube texture, the {001} component, predominated in the as-cast condition and was transformed into brass, copper and S type textures during the cold rolling process. There was practically no difference between the deformation textures at the two thickness reductions.

  4. Improved Fatigue Performance of Threaded Drillstring Connections by Cold Rolling

    Energy Technology Data Exchange (ETDEWEB)

    Kristoffersen, Steinar

    2002-01-01

    The research work presented in this thesis is concerned with analytical, numerical and experimental studies of the effect of cold rolling on the fatigue behaviour of threaded drillstring connections. A comprehensive literature study is made of the various effects on the fatigue behaviour of residual stresses introduced by mechanical deformation of notched components. Some of the effects studied are cyclic hardening behaviour after prestraining, cyclic creep, fatigue initiation in prestrained materials, short cracks and crack growth models including crack closure. Residual stresses were introduced in the surface of a smooth pipe by a rolling device to simulate a cold rolling process and verify the calculated residual stresses by measurements. Strain hardening and contact algorithm of the two bodies were incorporated in the FE analyses. Two significant errors were found in the commercial software package for residual stress evaluation, Restran v. 3.3.2a also called SINT, when using the Schajer method. The Schajer algorithm is the only hole-drilling algorithm without theoretical shortcomings, and is recommended when measuring large residual stress gradients in the depth direction. Using the Schajer method solved by in-house Matlab-routines good agreement between measured residual stress gradients and residual stress gradients from FE analyses was found. Full scale fatigue tests were performed on pipes cut from used drillstrings with notches of similar geometry as threads used in drillstring connections. The simulated threads consisted of four full depth helix notches with runouts at the surface. The pipe threads were cold rolled and fatigue tested in a full-scale four-point rotating bending fatigue testing rig. The test results showed that cold rolling had an effect on the crack initiation period. A major part of the fatigue life was with cracks observed at the notch root, but due to the increased fatigue crack propagation resistance the final fracture initiated at

  5. Experimental Study and Finite Element Polycrystal Model Simulation of the Cold Rolling Textures in a Powder Metallurgy Processed Pure Aluminum Plate

    Institute of Scientific and Technical Information of China (English)

    Liqing CHEN; Naoyuki Kanetake

    2005-01-01

    Ingot metallurgy (IM) aluminum has long been the subject and attracted the attention of many metallurgists and textural researchers of materials. Due to the introduction of large amounts of ex situ interfaces, however, the textures in powder metallurgy (PM) processed aluminum has been rarely reported. In this article, a pure aluminum plate was prepared via PM route. The starting billet was first produced with uni-axially cold compaction and flat hot-extrusion and then followed by cold rolling processes. The hot-extruded and cold rolling deformation textures of the pure PM aluminum at 50%, 80% and 90% cold rolling reductions were studied by orientation distribution functions (ODFs) analysis. The finite element polycrystal model (FEPM) was finally utilized to simulate the cold rolling textural evolution at various stages of cold rolling. In FEPM simulation, the initial hot-extruded textures were taken into account as inputs. The results showed that typical β-fiber texture formed in pure PM aluminum with the cold rolling reduction increased till 80%, and there was not much change after excessive cold rolling deformation.Homogeneous slip is not the only deformation mode in PM processed pure aluminum plate at over 80% cold rolling reduction. The experimental results were qualitatively in good agreement with the simulated ones.

  6. Finite element analysis of deformation characteristics in cold helical rolling of bearing steel-balls

    Institute of Scientific and Technical Information of China (English)

    曹强; 华林; 钱东升

    2015-01-01

    Due to the complexity of investigating deformation mechanisms in helical rolling (HR) process with traditional analytical method, it is significant to develop a 3D finite element (FE) model of HR process. The key forming conditions of cold HR of bearing steel-balls were detailedly described. Then, by taking steel-ball rolling elements of the B7008C angular contact ball bearing as an example, a completed 3D elastic-plastic FE model of cold HR forming process was established under SIMUFACT software environment. Furthermore, the deformation characteristics in HR process were discovered, including the forming process, evolution and distribution laws of strain, stress and damage based on Lemaitre relative damage model. The results reveal that the central loosening and cavity defects in HR process may have a combined effect of large negative hydrostatic pressure (positive mean stress) caused by multi-dimensional tensile stresses, high level transverse tensile stress, and circular-alternating shear stress in cross section.

  7. Robust shape control in a sendzimir cold-rolling steel mill

    NARCIS (Netherlands)

    Bates, D.G.; Ringwood, J.V.; Holohan, A.M.

    1997-01-01

    The shape control problem for a Sendzimir 20-roll cold rolling steel mill is characterised by operation over a wide range of conditions arising from roll changes, changes in rolling schedules and changes in material gauge, width and hardness. Previous approaches to the problem suggest storing a larg

  8. Structure and mechanical properties of austenitic steel after cold rolling

    Directory of Open Access Journals (Sweden)

    A. Kurc-Lisiecka

    2011-02-01

    Full Text Available Purpose: The aim of the paper is to determine the influence of the cold plastic deformation within the range 18-79% and heat treatment in a temperature range of 500 to 700°C on the microstructure and mechanical properties of austenitic stainless steel grade X5CrNi18-8.Design/methodology/approach: The investigations included observations of the microstructure on a light microscope, researches of mechanical properties in a static tensile test and hardness measurements made by Vickers’s method. The analysis of the phase composition was carried out on the basis of X-ray researches. Whereas, X-ray quantitative phase analysis was carried out by the Averbach Cohen method.Findings: Heat treatment of X5CrNi18-8 stainless steel in the range 500-700°C causes a significant decrease of the mechanical properties (Rm, Rp0.2 and increase of elongation (A. Hardness of investigated steel drops with decrease of cold working degree and increase of heat treatment temperature.Research limitations/implications: The analysis of the obtained results permits to state that the heat treatment causes an essential changes of the microstructure connected with fading of cold deformation. Heating of cold rolled austenitic stainless steels can cause a reverse transformation α’ → γ.Practical implications: Two-phase structure α’+γ of austenitic Cr-Ni steel in deformed state working at elevated temperature undergo a transformation. It significantly influences mechanical properties of steel. Austenite phase undergoes a recrystallization, while martensite α’ phase undergoes reverse transformation.Originality/value: The analytic dependence of the yield point of the investigated steel on the cold working degree in cold rolling process has been confirmed. Revealing this relation is of essential practical importance for the technology of sheetmetal forming of austenitic steel.

  9. Microstructural evolution of lamellar cementite in eutectoid steels by cold rolling%共析钢中片层状渗碳体冷轧后的形态变化

    Institute of Scientific and Technical Information of China (English)

    王莉; 郝士明

    2005-01-01

    The pearlitic transformation and the deformation behavior of lamellar cementite after cold rolling in eutectoid steels Fe-0.76%C-0. 137%Mn (mass fraction) were studied by means of Formastor-F (Full Automatic Transformation Testing Instrument) and field emission scanning electronic microscopy (FESEM) observation. Fine and coarse pearlite were obtained in the eutectoid steels austenitized at 900 ℃ for 15min, then hold at 620 ℃ for 90 s and 690 ℃ for 7 h, respectively. Thedeformation behavior of cold rolled lamellar cementite could be classified as: cleavage fracture, inhomogeneous slip, fragmentation, thinning or necking, and homogeneous bending. The cementite lamellae with the thickness of more than 100 nm could be deformed plastically.

  10. Simulation of Multiple Cold Rolls Progressive Forming for Non-symmetrical Channel Section

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In cold roll forming process, the sheet is progressively formed into a very complex three dimensional surface. The design procedure for the roll formed products, forming rolls, and roll pass sequences was considered more an art than a science. Good roll pass design was the key to successful roll forming. In order to reduce forming defects and trial production cost, computer simulation of cold roll forming was employed. Based on the Updated-Lagrange method in the deformation mechanics, a theoretical model of elastic-plastic large deformation spline finite strip method is proposed in this paper. The method is employed to analyze the progressive forming process of non-symmetrical section, and the displacement, the stress and the strain along rolling direction during the multiple cold rolls forming process are got. This program written in C Language can be used to analyze other simple cross sectional profiles also.

  11. Control Strategies of Asymmetric Strip Shape in Six-High Cold Rolling Mill%Control Strategies of Asymmetric Strip Shape in Six-High Cold Rolling Mill

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yun; YANG Quan; WANG Xiao-chen

    2011-01-01

    It is a complicated problem for cold-rolled strip to improve asymmetric strip shape in strip production. A roll system and strip coupled model of six-high cold rolling mill was established with finite element method to estimate the effect of intermediate roll shifting, tilting, symmetric and asymmetric bending technologies on strip profile. To reduce asymmetric defects of strip shape as much as possible, some control strategies were proposed, including tilting and asymmetric bending of intermediate roll and work roll. The combinations of these three control strategies can effectively eliminate asymmetric strip shape defects. Finally, the closed-loop control model of asymmetric flat- ness at the last stand was given, and the flatness control system with the function of asymmetric strip shape control was also designed for cold tandem mill.

  12. Cell and band structures in cold rolled polycrystalline copper

    DEFF Research Database (Denmark)

    Ananthan, V.S.; Leffers, Torben; Hansen, Niels

    1991-01-01

    The effect of plastic strain on the deformation microstructure has been investigated in polycrystalline copper rolled at room temperature to 5, 10, 20, and 30% reduction in thickness equivalent strain 0.06-0.42). Results from transmission electron microscopy (TEM) observations show that dense...... on {111}. Finally, the evolution of the deformation microstructure in copper is compared with that observed in other face centred cubic metals, especially aluminium....

  13. Microstructural and textural changes in a severely cold rolled boron-added interstitial-free steel

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Rajib [Indian Institute of Technology, Kanpur 208 016 (India); R and D Division, Tata Steel, Jamshedpur (India)], E-mail: rajib.saha@tatasteel.com; Ray, R.K. [Indian Institute of Technology, Kanpur 208 016 (India); R and D Division, Tata Steel, Jamshedpur (India)

    2007-11-15

    The severe cold rolling of a single sheet of boron-added Ti + Nb IF steel at room temperature can produce nano- to ultrafine-sized grains. The number fraction of high-angle grain boundaries increases up to 98% cold rolling and then shows a perceptible decrease after further cold rolling. The coincidence site lattice (CSL) boundary fraction increases continuously with deformation. The most prominent among these CSL boundaries are the {sigma}3, {sigma}11 and {sigma}13b types.

  14. Texture and microstructure development in a cold-rolled duplex stainless steel annealed at 800 C

    Energy Technology Data Exchange (ETDEWEB)

    Shek, C.H. (Dept. of Mechanical Engineering, Univ. of Hong Kong (Hong Kong)); Shen, G.J. (Analysis and Test Centre, Southeast Univ., Nanjing (China)); Lai, J.K.L. (Dept. of Applied Science, City Polytechnic of Hong Kong (Hong Kong)); Duggan, B.J. (Dept. of Mechanical Engineering, Univ. of Hong Kong (Hong Kong))

    1994-01-01

    A cast of austenitic-ferritic duplex stainless steel was rolled 85% and then annealed at 800 C to study the microstructural and texture changes in the material caused by these mechanical and thermal treatments. The austenite in the duplex alloy behaves as typical low SFE materials when rolled as well as annealed but larger spreads in orientation were observed, compared with rolled and annealed brass. The cold-rolled ferrite mainly consists of long microbands and has texture similar to cold-rolled carbon steel. Upon annealing, the ferrite undergoes recovery only and the rolling texture is thus retained. (orig.)

  15. The cold-rolling behaviour of AZ31 tubes for fabrication of biodegradable stents.

    Science.gov (United States)

    Zhang, Yaowu; Kent, Damon; Wang, Gui; StJohn, David; Dargusch, Matthew S

    2014-11-01

    Mg alloys are receiving considerable attention for biomedical stents due to their combination of good mechanical properties and high biodegradability. Cold rolling is necessary to process Mg alloy tubes before final drawing and fabrication of the magnesium stents. In this paper, cold-rolled tubes were subjected to a cross-sectional reduction rate (ε) of up to 19.7%, and were further processed at various ratios of wall-thickness to diameter reduction (Q) from 0 to 2.24 with a constant ε of 19.7%. The results show that the cold-rolled tubes exhibited a rise in ultimate tensile strength (UTS), yield strength (YS), and a reduction in elongation as ε increased from 5.5% to 19.7%. UTS, YS and elongation decreased when Q was increased from 0 to 2.24. Mechanical twinning was observed and analysed. Extension twins increased with increasing ε and were almost saturated at a ε of 16.5%. Extension twins play an important role in determining the evolution of mechanical behaviour in the case of increasing ε, whilst contraction/double twins and secondary extension twins have a large effect on mechanical behaviour in the case of varying Q. The results indicate that the proportions and types of twins play a major role in determining the mechanical behaviour of the AZ31 tubes.

  16. Synthesis and Characterization of Hot-Roll and Cold-Roll Byproduct-Derived Strontium Hard Ferrites

    Directory of Open Access Journals (Sweden)

    H. S. Woon

    2009-01-01

    Full Text Available Problem statement: Ceramic permanent magnets or more commonly known as strontium hexagonal ferrites have been widely used in permanent magnetic materials as they provide high remanence, high coercivity, relatively high energy product and good chemical stability. In this study, we treated factory byproduct from hot-roll and cold-roll steel industry was used as raw material in synthesis of strontium hexagonal hard ferrites. Approach: X-Ray Diffraction (XRD was employed to confirm the formation of strontium hard ferrite compound. Vibrating Sample Magnetometer (VSM was used to analyze the magnetic properties of samples prepared. Results: The magnetic properties, namely remanence and coercivity of factory byproduct-derived strontium hard ferrites were compared. The cold-roll-derived strontium hard ferrite showed higher remanence in this study. Conclusion: This implied that cold-roll byproduct was a better candidate to replace hematite in preparation of strontium hard ferrites compared to hot-roll byproduct.

  17. Effect of cold-rolling on tensile strength of SiCw/Al composite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wenlong; ZHANG Mu; GU Mingyuan; WANG Dezun; YAO Zhongkai

    2003-01-01

    SiCw/Al composite was fabricated through a squeeze cast route and cold rolled to about 30%, 50% and 70% reduction in thickness, respectively. The length of whiskers in the composite before and after rolling was examined using SEM. Some of the rolled composites were recrystallization annealed to remove the work hardening of matrix alloy. The tensile strength of the rolled and annealed SiCw/Al composites was examined and then associated with the change of the whisker length and the work hardening of matrix alloy. It was found that the tensile strength is a function of the degree of cold rolling. For the cold rolled composites, with the increase in the degree of cold rolling, the tensile strength increases at first, and decreases when the degree of cold rolling exceeds 50%. For the annealed ones, however, the tensile strength decreases monotonously with the increase in rolling degree. The different changes in tensile strength between the rolled and annealed composites could be attributed to the result of the competition between the work hardening of matrix resulting from the cold rolling and the work softening arising from the change of whisker length.

  18. Effect of Cold-rolling on Hardness of SiCw/Al Composite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen-long; ZHANG Mu; WANG De-zun; YAO Zhong-kai; GU Ming-yuan

    2004-01-01

    A SiCw/Al composite was fabricated through a squeeze cast route and cold rolled to about 30%, 50% and 70% reduction in thickness, respectively. The length of whiskers in the composite before and after rolling was examined using SEM. Some of the rolled composites were annealed by recrystallizing to remove the work hardening of the matrix alloy. The hardness of the rolled and annealed SiCw/Al composites was examined and then associated with the change of the whisker length and the work hardening of the matrix alloy. It was found that the hardness was a function of the degree of cold rolling. For the cold rolled composites, with the increase in the degree of cold rolling, the hardness increases at first, and decreases when the degree of cold rolling exceeds 50%. For the annealed ones, however, the hardness decreases monotonously with the increase in rolling degree. The different changes in hardness between the rolled and annealed composites could be attributed to a result of the competition between the work hardening of the matrix resulting from the cold rolling and the work softening arising from the change of whisker length.

  19. Tribological Testing of Anti-Adhesive coatings for Cold Rolling Mill Rolls—Application to TiN-Coated Rolls

    Science.gov (United States)

    Ould, Choumad; Gachon, Yves; Montmitonnet, Pierre; Badiche, Xavier

    2011-05-01

    Roll life is a major issue in cold strip rolling. Roll wear may result either in too low roll roughness, bringing friction below the minimum requested for strip entrainment; or it may degrade strip surface quality. On the contrary, adhesive wear and transfer ("roll coating", "pick up") may form a thick metallic deposits on the roll which increases friction excessively and degrades strip surface again [1]. The roll surface, with the help of a materials-adapted lubricant, must therefore possess anti-wear and anti-adhesive properties. Thus, High Speed Steeel (HSS) rolls show superior properties compared with standard Cr-steel rolls due to their high carbide surface coverage. Another way to improve wear and adhesion properties of surfaces is to apply hard metallic (hard-Cr) or ceramic coatings. Chromium is renowned for its excellent anti-wear and anti-adhesive properties and may serve as a reference. Here, as a first step towards alternative, optimised coatings, a PVD TiN coating has been deposited on tool steels, as previous attempts have proved TiN to be rather successful in cold rolling experiments [2,3]. Different tribological tests are reported here, giving insight in both anti-adhesive properties and fatigue life improvement.

  20. Texture evolution in the Fe-30.5Mn-8.0Al-1.2C and Fe-30.5Mn-2.1Al-1.2C steels upon cold rolling

    OpenAIRE

    Souza,Fabrício Mendes; Padilha, Angelo Fernando; Gutierrez-Urruti, Ivan; Raabe, Dierk

    2016-01-01

    Crystallographic textures of the austenitic low-density Fe-30.5Mn-8.0Al-1.2C (8Al) and Fe-30.5Mn-2.1Al-1.2C (2Al) (wt.%) steels were examined during cold rolling by means of electron backscatter diffraction (EBSD) and electron channeling contrast imaging (ECCI). Random oriented grains orient towards Goss- and brass-components along the α-fiber as the strain increased, with activation of slip, mechanical twinning, and shear banding, for both steels. S- and copper-orientations ...

  1. Combustion Synthesis Reaction Behavior of Cold-Rolled Ni/Al and Ti/Al Multilayers

    Science.gov (United States)

    2011-04-01

    pulse. Such exothermic reactions in multilayers can be used as local heat sources to melt solders or brazes and thus join components in a variety of...4 Figure 1. Schematic of the cold-rolling procedure. diffraction (XRD) examination using Cu Kα radiation. The unreacted as-cold-rolled Ni/Al

  2. Adhesiveness of cold rolled steels for car body parts

    Directory of Open Access Journals (Sweden)

    Kleiner Marques Marra

    2007-09-01

    Full Text Available The aim of this work was to evaluate the adhesiveness of uncoated and zinc-electrogalvanized steel sheets used in the automotive industry. Three types of adhesives, one acrylic and two epoxy resins, were employed to join low carbon cold rolled steels, one uncoated and another electrogalvanized, both previously degreased or chemically pickled. Mechanical strength of the joints was evaluated by the T-peel and tensile strength tests. Steel grade, surface condition and heating below the cure temperatures did not influence the joints' mechanical strength. However, their shear strength decreased drastically as the test temperature increased. The exposure of the joints to an atmosphere with 90% relative humidity at 40 °C caused reduction of their shear strength. Epoxy adhesives showed higher mechanical strength, but exhibited higher degradation by humidity.

  3. Step Structure in Cold-Rolled Deformed Nanocrystalline Nickel

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xi-Yan; WU Xiao-Lei; XIA Bao-Yu; ZHOU Ming-Zhe; ZHOU Shi-Jie; JIA Chong

    2005-01-01

    @@ The microstructure characteristic of the cold-rolled deformed nanocrystalline nickel metal is studied by transmission electron microscopy. The results show that there are step structures nearby the grain boundary (GB),and the contrast of stress field in front of the step corresponds to the step in the shape. It is indicated that the interaction between twins and dislocations is not a necessary condition to realizing the deformation. In the later stage of the deformation when the grain size becomes about 100nm, the deformation can depend upon the moving of the boundary of the stack faults (SFs) which result from the partial dislocations emitted from GBs.However, when the size of SFs grows up, the local internal stress which is in front of the step gradually becomes higher. When this stress reaches a critical value which stops the gliding of the partial dislocations, the SFs will stop to grow up and leave a step structure behind.

  4. TOPICAL REVIEW: Progress in cold roll bonding of metals

    Science.gov (United States)

    Li, Long; Nagai, Kotobu; Yin, Fuxing

    2008-04-01

    Layered composite materials have become an increasingly interesting topic in industrial development. Cold roll bonding (CRB), as a solid phase method of bonding same or different metals by rolling at room temperature, has been widely used in manufacturing large layered composite sheets and foils. In this paper, we provide a brief overview of a technology using layered composite materials produced by CRB and discuss the suitability of this technology in the fabrication of layered composite materials. The effects of process parameters on bonding, mainly including process and surface preparation conditions, have been analyzed. Bonding between two sheets can be realized when deformation reduction reaches a threshold value. However, it is essential to remove surface contamination layers to produce a satisfactory bond in CRB. It has been suggested that the degreasing and then scratch brushing of surfaces create a strong bonding between the layers. Bonding mechanisms, in which the film theory is expressed as the major mechanism in CRB, as well as bonding theoretical models, have also been reviewed. It has also been showed that it is easy for fcc structure metals to bond compared with bcc and hcp structure metals. In addition, hardness on bonding same metals plays an important part in CRB. Applications of composites produced by CRB in industrial fields are briefly reviewed and possible developments of CRB in the future are also described. Corrections were made to the abstract and conclusion of this article on 18 June 2008. The corrected electronic version is identical to the print version.

  5. TOPICAL REVIEW Progress in cold roll bonding of metals

    Directory of Open Access Journals (Sweden)

    Long Li, Kotobu Nagai and Fuxing Yin

    2008-01-01

    Full Text Available Layered composite materials have become an increasingly interesting topic in industrial development. Cold roll bonding (CRB, as a solid phase method of bonding same or different metals by rolling at room temperature, has been widely used in manufacturing large layered composite sheets and foils. In this paper, we provide a brief overview of a technology using layered composite materials produced by CRB and discuss the suitability of this technology in the fabrication of layered composite materials. The effects of process parameters on bonding, mainly including process and surface preparation conditions, have been analyzed. Bonding between two sheets can be realized when deformation reduction reaches a threshold value. However, it is essential to remove surface contamination layers to produce a satisfactory bond in CRB. It has been suggested that the degreasing and then scratch brushing of surfaces create a strong bonding between the layers. Bonding mechanisms, in which the film theory is expressed as the major mechanism in CRB, as well as bonding theoretical models, have also been reviewed. It has also been showed that it is easy for fcc structure metals to bond compared with bcc and hcp structure metals. In addition, hardness on bonding same metals plays an important part in CRB. Applications of composites produced by CRB in industrial fields are briefly reviewed and possible developments of CRB in the future are also described.

  6. Strain distribution of strips with spherical inclusion during cold rolling

    Institute of Scientific and Technical Information of China (English)

    YU Hai-liang; BI Hong-yun; LIU Xiang-hua; TU Yan-feng

    2008-01-01

    The deformation of 304 stainless steel strips with a spherical inclusion during cold rolling was simulated by 3D finite element method, and the strain distribution was calculated for a variety of the material attribution of inclusion (hard inclusions and soft inclusions) and the inclusion size (10, 20, 30, 40, and 50 μm). During rolling, the strain in front of inclusion is larger than that in rear of inclusion for both the hard and soft inclusions. For hard inclusions, the strain in front and rear of inclusions is larger than that of inclusions, and the maximum and minimum strains increase with the increase of inclusion diameter (from 10 μm to 50 μm). For soft inclusions, the strain in front and rear of inclusions is smaller than that of inclusions, and the maximum and minimum strains decrease with the increase of inclusion sizes when the inclusion diameter is larger than 20 μm but increase when the inclusion diameter is smaller than 20 μm. Finally, the relationship between the inclusion deformation and the crack generation was discussed.

  7. Effects of microalloying on hot-rolled and cold-rolled Q&P steels

    Science.gov (United States)

    Azevedo de Araujo, Ana Luiza

    Third generation advanced high strength steels (AHSS) have been a major focus in steel development over the last decade. The premise of these types of steel is based on the potential to obtain excellent combinations of strength and ductility with low-alloy compositions by forming mixed microstructures containing retained austenite (RA). The development of heat treatments able to achieve the desired structures and properties, such as quenching and partitioning (Q&P) steels, is driven by new requirements to increase vehicle fuel economy by reducing overall weight while maintaining safety and crashworthiness. Microalloying additions of niobium (Nb) and vanadium (V) in sheet products are known to provide strengthening via grain refinement and precipitation hardening and may influence RA volume fraction and transformation behavior. Additions of microalloying elements in Q&P steels have not been extensively studied to date, however. The objective of the present study was to begin to understand the potential roles of Nb and V in hot-rolled and cold-rolled Q&P steel. For that, a common Q&P steel composition was selected as a Base alloy with 0.2C-1.5Si-2.0Mn (wt. %). Two alloys with an addition of Nb (0.02 and 0.04 wt. %) and one with an addition of V (0.06 wt. %) to the Base alloy were investigated. Both hot-rolled and cold-rolled/annealed Q&P simulations were conducted. In the hot-rolled Q&P study, thermomechanical processing was simulated via hot torsion testing in a GleebleRTM 3500, and four coiling temperatures (CT) were chosen. Microstructural evaluation (including RA measurements via electron backscattered diffraction - EBSD) and hardness measurements were performed for all alloys and coiling conditions. The analysis showed that Nb additions led to overall refinement of the prior microstructure. Maximum RA fractions were measured at the 375 °C CT, and microalloying was associated with increased RA in this condition when compared to the Base alloy. A change in

  8. MECHANICS ANALYSIS ON PRECISE FORMING PROCESS OF EXTERNAL SPLINE COLD ROLLING

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dawei; LI Yongtang; FU Jianhua; ZHENG Quangang

    2007-01-01

    According to the suitable assumption, the deformation process of external spline cold rolling is analyzed. By the graphing method, the slip-line field of plastically deforming area in process of external spline cold rolling is set up. Different friction-conditions are used in different contact areas in order to realistically reflect the actual situation. The unit average pressure on contact surface of the rolling process is solved according to the stress filed theory of slip-line. And the formulae of the rolling-force and rolling-moment are established. The theoretical result is well consistent with the finite element analysis. A theoretical basis is provided for the precise forming process of spline cold rolling and the production of external splined shafts.

  9. Modeling, simulation and identification for control of tandem cold metal rolling

    Directory of Open Access Journals (Sweden)

    Péricles Guedes Alves

    2012-12-01

    Full Text Available This paper describes a modeling procedure for tandem cold metal rolling, including the linearization step and system identification for control. The tandem cold rolling process is described by a mathematical model based on algebraic equations developed for control purposes and empirical relations. A state-space model is derived and detailed analyses in open loop are presented, concerning the sensitivity with regard to the variations in process parameters and results for the application of a new subspace identification method are compared with classical methodologies. Therefore, this work intents to be a contribution for developments in new control strategies for tandem cold rolling process that offer the potential to reduce the design efforts, the commissioning time and maintenance in rolling mills. The preliminary results obtained with this model have shown reasonable agreement with operational data presented at literature for industrial cold rolling process.

  10. 大应变量冷轧金属Ni再结晶过程中∑3晶界演化%EVOLUTION OF ∑3 BOUNDARIES DURING RECRYSTALLIZATION OF COLD-ROLLED NICKEL DEFORMED TO HIGH STRAIN

    Institute of Scientific and Technical Information of China (English)

    张玉彬; A.Godfrey; 刘伟; 刘庆

    2009-01-01

    应用电子背散射衍射技术(EBSD)和电子通道衍衬成像技术(ECC)研究了大应变量(96%)冷轧纯度为99.996%的金属Ni在低温再结晶过程中∑3晶界的演化.研究表明,基于EBSD数据,∑3晶界可以分为两类--孪晶型和非孪晶型∑3晶界,二者可通过晶界取向差与60°的偏差△θ来区分.EBSD定位观察再结晶过程的结果表明,非共格孪晶是由共格孪晶发展而来;绝大部分∑3~n(n>1)晶界由晶核与其n次孪晶相遇而形成,并且晶界含量随着n的增加显著降低.大部分非孪晶型∑3晶界由孪晶型∑3晶界与小角晶界(∑1)相遇反应而来,可能比孪晶型∑3晶界更能够阻断大角晶界网络.%The concept of grain boundary engineering (GBE) has been proposed based on the fact that many studies have demonstrated that boundaries associated with low ∑-value coincident site lattice (CSL) misorientations show higher resistance to intergranular fracture and corrosion, reduced susceptibility to impurity segregation and superior ductility. It is commonly accepted that for fcc metals of low to medium stacking fault energy metals, including Ni and many Ni-alloys, the most important CSL boundary for the GBE process is a ∑3 boundary, the occurrence of which is dominated by the formation of annealing twins. Moreover, it has been found that repetitive thermo-mechanical processing can be used to increase further the fraction of ∑3 (and ∑3~n (n >1)) boundaries. However, the mechanism for this is not yet clear. Therefore, an investigation on the evolution of ∑3 boundaries during recrystallization is important for understanding the mechanisms of GBE for those materials. In the present paper the evolution of ∑3 boundaries during recrystallization in a 96% cold-rolled sample of pure nickel of 99.996% purity has been explored using orientation maps obtained using electron backscatter diffraction (EBSD). Each orientation map was taken from the same area after annealing for

  11. TANDEM COLD MILL PROCESS STABILITY IMPROVEMENT WITH CHROME PLATED WORK ROLLS APPLICATION

    Directory of Open Access Journals (Sweden)

    Sergio Luiz Muratori

    2012-09-01

    Full Text Available The stability of a tandem cold mill is essential to assure the thickness control, the main attribute of cold rolled steel sheets. This stability can be defined as the capability to control the process variables that act direct at the thickness. Among the most important variables are the first stand (mill linear speed and the sheet speed at the interstice ahead of it. This work shows how the chrome plated work rolls application improved this speed control and consequently the stability, which enabled an increase in the work roll rolling campaign (rolling sequence program in such a way significantly higher, compared to when using a non chrome plated work rolls. As results, significantly improvements of work rolls campaigns and the consequent increase of the equipment availability are presented.

  12. Numerical Treatments of Slipping/No-Slip Zones in Cold Rolling of Thin Sheets with Heavy Roll Deformation

    Directory of Open Access Journals (Sweden)

    Yukio Shigaki

    2015-04-01

    Full Text Available In the thin sheet cold rolling manufacturing process, a major issue is roll elastic deformation and its impact on roll load, torque and contact stresses. As in many systems implying mechanical contact under high loading, a central part is under “sticking friction” (no slip while both extremities do slip to accommodate the material acceleration of the rolled metal sheet. This is a crucial point for modeling of such rolling processes and the numerical treatment of contact and friction (“regularized” or not, of the transition between these zones, does have an impact on the results. Two ways to deal with it are compared (regularization of the stick/slip transition, direct imposition of a no-slip condition and recommendations are given.

  13. Evolution of fuel plate parameters during deformation in rolling

    Science.gov (United States)

    Durazzo, M.; Vieira, E.; Urano de Carvalho, E. F.; Riella, H. G.

    2017-07-01

    The Nuclear and Energy Research Institute - IPEN/CNEN-SP routinely produces the nuclear fuel necessary for operating its research reactor, IEA-R1. This fuel consists of fuel plates containing U3Si2-Al composites as the meat, which are fabricated by rolling. The rolling process currently deployed was developed based on information obtained from literature, which was used as a premise for defining the current manufacturing procedures, according to a methodology with an essentially empirical character. Despite the current rolling process being perfectly stable and highly reproducible, it is not well characterized and is therefore not fully known. The objective of this work is to characterize the rolling process for producing dispersion fuel plates. Results regarding the evolution of the main parameters of technological interest, after each rolling pass, are presented. Some defects that originated along the fuel plate deformation during the rolling process were characterized and discussed. The fabrication procedures for manufacturing the fuel plates are also presented.

  14. Development of recrystallization texture and microstructure in cold rolled copper

    Energy Technology Data Exchange (ETDEWEB)

    Necker, C.T. [Los Alamos National Lab., NM (United States); Doherty, R.D. [Drexel Univ., Philadelphia, PA (United States). Dept. of Materials Engineering; Rollett, A.D. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Materials Science and Engineering

    1996-12-31

    Oxygen free electronic copper, 99.995% purity, of two initial grain sizes, 50 {mu}m and 100 {mu}m, has been cold rolled to six strains of 1.0, 1.5, 2.0, 2.65, 3.5 and 4.5 (von Mises equivalents). The rolled materials were partially and fully recrystallized to study the development of recrystallization textures as a function of grain size, strain and fraction recrystallized. The initial textures were relatively random and the deformation textures show the classic {beta} fiber development. As strain is increased both materials produce increasingly intense cube recrystallization textures, (100)<001>, as measured both by x-ray diffraction and the electron backscatter pattern (EBSP) techniques. The strong cube recrystallization textures are a product of a higher than random frequency of cube nucleation sites. An additional factor is that cube regions grow larger than non-cube regions. The explanation of the cube frequency advantage is based on the development of large stored energy differences between cube orientations and neighboring orientations due to recovery of cube sites. Of several possible explanations of the cube orientation size advantage, the most plausible one is solute entrapment. At the higher strains the boundaries of cube grains encounter the deformation texture S components, (123)<634>, changing the boundary character to one of 40{degrees}<111>. These boundaries are more resistant to solute accumulation than random high angle boundaries, allowing the boundaries to migrate with less of a solute drag effect than a random high angle boundary.

  15. VISUAL SIMULATION OF COLD ROLL-FORMING BASED ON OBJECT ORIENTED PROGRAMMING

    Institute of Scientific and Technical Information of China (English)

    Zhang Lele; Tan Nanlin; Zhang Huadi; Liu Cai

    2004-01-01

    To simulate the process of cold roll-forming process, a new method is adopted.The theoretical foundation of this method is an elastic-plastic large deformation spline finite strip method based on object-oriented programming.Combined with the computer graphics technology, the visual simulation of cold roll-forming is completed and the system is established.By analyzing common channel steel, the process is shown and explained including theory method, model and result display.So the simulation system is already a kind of mature and effective tool to analyze the process of cold roll forming.

  16. The influence of microchemistry on the recrystallization texture of cold-rolled Al-Mn-Fe-Si alloys

    OpenAIRE

    Huang, K.; Y. J. Li; Marthinsen, K

    2015-01-01

    The recrystallization textures of a cold-rolled Al-Mn-Fe-Si model alloy with three different microchemistry states after non-isothermal annealing were studied. The microstructure and texture evolution have been characterized by EBSD. It is clearly demonstrated that the actual microchemistry state as determined by the homogenization procedure strongly influence the recrystallized grain size and recrystallization texture after nonisothermal annealing. High Mn content in solid solution promotes ...

  17. Cold rolling induced alloying behaviors in metallic multilayers

    Science.gov (United States)

    Wang, Zhe

    Phase transformation and atomic scale intermixing induced by deformation are important and fundamental issues in the mechanical alloying processes. Repeated cold rolling and folding experiments were performed on the metallic multilayers in order to study the deformation driven behaviors. Various binary systems such as isomorphous, eutectic and thermodynamically immiscible systems were studied. Moreover, monometallic Pd, Pt and Fe were selected in order to study the deformation driven recrystallization behavior. In Cu/Ni multilayers, the composition of the solid solution is revealed by an oscillation in the composition profile across the multilayers, which is different from the smoothly varying profile due to thermally activated diffusion. During the reaction, Cu mixed into Ni preferentially compared to Ni mixing into Cu, which is also in contrast to the thermal diffusion behavior. During the cold rolling of multilayers of Ni and V, deformation induces phase transformation and an interfacial mixing with suppression of nucleation of intermetallic phases. The results also demonstrate that between pure Ni and V layers a metastable fcc solid solution phase forms in Ni70V30, a metastable bcc solid solution phase forms in Ni30V70 and metastable fcc and bcc solid solution phases form in Ni57V43. Compared to the stored energy due to dislocation and interfaces, the excess chemical free energy from the interfacial mixing is the largest portion of total stored energy from deformation, which represents a form of mechanochemical transduction. The difference in the intermixing behaviors between Cu/Ni and Ni/V systems is due to that the systems have different heat of mixing and interface characters. Deformation of Cu/Fe multilayers yields a smooth and monotonic variation in the composition profile. From the local composition consumption it is revealed that that Fe mixes into Cu preferentially than Cu mixing into Fe. The room temperature deformation driven recrystallization was

  18. Comparative study on the corrosion behavior of the cold rolled and hot rolled low-alloy steels containing copper and antimony in flue gas desulfurization environment

    Science.gov (United States)

    Park, S. A.; Kim, J. G.; He, Y. S.; Shin, K. S.; Yoon, J. B.

    2014-12-01

    The correlation between the corrosion and microstructual characteristics of cold rolled and hot rolled low-alloy steels containing copper and antimony was established. The corrosion behavior of the specimens used in flue gas desulfurization systems was examined by electrochemical and weight loss measurements in an aggressive solution of 16.9 vol % H2SO4 + 0.35 vol % HCl at 60°C, pH 0.3. It has been shown that the corrosion rate of hot rolled steel is lower than that of cold rolled steel. The corrosion rate of cold rolled steel was increased by grain refinement, inclusion formation, and preferred grain orientation.

  19. Entry and Exit Stress Variation of Cold Rolling Strip

    Institute of Scientific and Technical Information of China (English)

    WANGDong—cheng

    2012-01-01

    The shortcomings of an exit stress variation formula which has been well accepted are analyzed~ it is found that the exit stress variation formula violates the premise of the law of volume constancy. The shortcomings of an en- try stress variation formula are analyzed too, and the basic assumption of the formula is uniform exit velocity. How- ever, for a rigid-plastic material uniform exit velocity implies that the lateral distributioi1 of elongation is uniform, so the exit stress must be uniform and any type of flatness defect is impossible, which is contrary to the practice. In fact, entry and exit velocity variation influence entry and exit stress variation, and entry and exit stress variation in- fluence entry and exit velocity variation too, so a precise explicit stress variation formula cannot be got easily. Con- sidering the relationship between stress variation and velocity variation, an iteration method is presented to calculate entry and exit stress variation of cold rolling strip. To avoid divergent phenomenon of the iteration course, a relaxa- tion factor method is adopted. The calculation results are compared with the entry and exit stress variation formula commonly used by many researchers. The difference is remarkable, while the result calculated agree more well with measured result if the exit elastic recovery zone is considered. Specially, the incoming flatnessI propagate efficiency calculated ~ives a more realistic result.

  20. Modeling and Extended State Observer Based Dynamic Surface Control for Cold Rolling Mill System

    Directory of Open Access Journals (Sweden)

    Xu Li

    2016-01-01

    Full Text Available The modeling and control problems are investigated for cold rolling mill system. Firstly, we establish a monitor automatic gauge control (MAGC model for a practical cold rolling mill system. The new model is with mismatched uncertainties. Then, an extended state observer (ESO is developed to estimate uncertainties. In the general high-order systems, the ESO is also used to estimate states. By dynamic surface control method, we design the controller to guarantee stabilization of the cold rolling mill system. Furthermore, we extend proposed method to general high-order systems, in which we analyze the difference from cold rolling mill system. Finally, simulation results for MAGC system are presented to demonstrate the effectiveness of the proposed control strategy.

  1. Microstructural Development and Deformation Mechanisms during Cold Rolling of a Medium Stacking Fault Energy TWIP Steel

    Institute of Scientific and Technical Information of China (English)

    K.A. Ofei; L. Zhao; J. Sietsma

    2013-01-01

    The magnetic response,microstructural and texture changes occurring during cold rolling of a Fe-14Mn-0.64C-2.4Al-0.25Si medium stacking fault energy TWlP (twinning induced plasticity) steel have been studied by X-ray diffraction and magnetic techniques.The changes in the sub-grain size (Ds),probability of stacking fault formation (Psf) and microstrain in the material as cold rolling progressed were determined by using a modified version of the Williamson and Hall equation.A strong development of the crystallographic texture with increasing deformation was observed.Deformation-induced formation of a small fraction α'-martensite was observed,indicating that the steel also exhibits y → α'-martensite transformation during cold rolling,which is discussed via the changes of the stacking-fault probability and the texture development during cold rolling.

  2. Composite Aluminum-Copper Sheet Material by Friction Stir Welding and Cold Rolling

    OpenAIRE

    Kahl, S; Osikowicz, W

    2013-01-01

    An aluminum alloy and a pure copper material were butt-joined by friction stir welding and subsequently cold rolled. The cold-rolling operation proved to be very advantageous because small voids present after friction stir welding were closed, the interface area per material thickness was enlarged, a thin intermetallic layer was partitioned, and the joint was strengthened by strain hardening. Tensile test specimens fractured in the heat-affected zone in the aluminum material; tensile strength...

  3. Research on the properties of laser welded joints of aluminum killed cold rolled steel

    Institute of Scientific and Technical Information of China (English)

    阎启; 曹能; 俞宁峰

    2002-01-01

    Aluminum killed cold rolled steel used for automobiles was welded shows that high quality of welding can be realized at welding speed of laser welded joints for aluminum killed cold rolled steel increased compared to those of the base metal while the formability decreased. Forming limit diagram of joint material indicated that the laser weld seam should avoid the maximum deformation area of automobile parts during the designing period for the position of weld seam.

  4. The Research on Optimization of Edge Drop Control for Cold Tandem Rolling Mill

    Science.gov (United States)

    Zhou, Xiao-Min; Yue, Xiao-Xue

    2016-05-01

    The cold tandem rolling of metal strip presents a significant control challenge because of nonlinearities and process complexities. And reducing edge drop of cold rolling strips and meeting uniform thickness will be a new tough shape theories and technologies. In this paper, the existing edge drop control are analyzed and optimized. The simulation results and practical data show that the optimized control system can effectively control the edge drop.

  5. Study Friction Distribution during the Cold Rolling of Material by Matroll Software

    Science.gov (United States)

    Abdollahi, H.; Dehghani, K.

    2007-04-01

    Rolling process is one of the most important ways of metal forming. Since the results of this process are almost finished product, therefore controlling the parameters affecting this process is very important in order to have cold rolling products with high quality. Among the parameters knowing the coefficient of friction within the roll gap is known as the most significant one. That is because other rolling parameters such as rolling force, pressure in the roll gap, forward slip, surface quality of sheet, and the life of work rolls are directly influenced by friction. On the other hand, in rolling calculation due to lake of a true amount for coefficient of friction a supposed value is considered for it. In this study, a new software (Matroll), is introduced which can determine the coefficient of friction (COF) and plot the friction hills for an industrial mill. Besides, based on rolling equations, it offers about 30 rolling parameters as outputs. Having the rolling characteristics as inputs, the software is able to calculate the coefficient of friction. Many rolling passes were performed on real industrial aluminum mill. The coefficient of friction was obtained for all passes. The results are in good agreement with the findings of the other researchers.

  6. Research on the expanding deformation of ring radius in cold profiled ring rolling process

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Cold profiled ring rolling is an advanced local plastic deformation technology widely used to precisely manufacture various complex seamless ring parts.It plays an important role in many industrial fields such as aeronautics,astronautics,automobile,bearings,etc.In the cold ring rolling process,the ring radius expands gradually with the increase of the feeding amount(i.e.rolling reduction),and the expanding deformation of the ring radius is closely related to the rolling reduction.It is very important to investigate the expanding deformation of ring radius for the precise control of ring dimensions and the design of feeding movement.In this paper,the relation between the expanding deformation of the ring radius and the rolling reduction in the stepped ring rolling process,a typical profiled ring rolling process,is analyzed by using analytical method.The results show that the growth amount of the filling depth of groove can’t exceed the rolling reduction,that in the inner stepped ring rolling process,the curves of the outer radius and big inner radius with the rolling reduction are monotonous,ascending and concave,i.e.,the outer radius and big inner radius expand faster and faster with the increase of the rolling reduction,and that in the outer stepped ring rolling process,the curves of the inner radius and small outer radius with the rolling reduction are also monotonous,ascending and concave,i.e.,the inner radius and small outer radius expand faster and faster with the increase of the roll reduction.

  7. Magnetostriction of heavily deformed Fe–Co binary alloys prepared by forging and cold rolling

    Energy Technology Data Exchange (ETDEWEB)

    Yamaura, Shin-ichi, E-mail: yamaura@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577 (Japan); Nakajima, Takashi [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577 (Japan); Satoh, Takenobu; Ebata, Takashi [Tohoku Steel, Co., Ltd., 23 Nishigaoka, Murata, Murata-machi, Shibata 989-1393 (Japan); Furuya, Yasubumi [North Japan Research Institute for Sustainable Energy, Hirosaki University, 2-1-3 Matsubara, Aomori 030-0813 (Japan)

    2015-03-15

    Highlights: • The as-forged Fe{sub 25}Co{sub 75} alloy shows the magnetostriction of 108 ppm. • The as-cold rolled Fe{sub 25}Co{sub 75} alloy shows the magnetostriction of 140 ppm. • Magnetostriction of Fe–Co alloy reached the maximum in a single bcc state. • Fcc phase is harmful to the increase in magnetostriction of Fe–Co alloy. • Fcc phase precipitation in Fe–Co alloy can be suppressed by cold rolling. - Abstract: Magnetostriction of Fe{sub 1−x}Co{sub x} (x = 50–90 at%) alloys prepared by forging and subsequent cold-rolling was studied as functions of alloy compositions and thermomechanical treatments. Magnetostriction of the as-forged Fe{sub 25}Co{sub 75} alloy was 108 ppm and that of the as-cold rolled Fe{sub 25}Co{sub 75} alloy measured parallel to the rolling direction (RD) was 128 ppm. The cold-rolled Fe{sub 25}Co{sub 75} alloy possessed a nearly {1 0 0}<0 1 1> texture, leading to the maximum magnetostriction of 140 ppm when measured at an angle of 45° to RD. Moreover, the fully annealed Fe{sub 25}Co{sub 75} and Fe{sub 20}Co{sub 80} alloys were gradually cold rolled and magnetostriction were measured. Results showed that the magnetostriction of those cold-rolled alloys drastically increased with increasing reduction rate. According to the XRD and TEM observations, intensity of the fcc peak gradually decreased with increasing reduction rate and that the alloys became to be in a bcc single state at a reduction rate higher than 90%, leading to a drastic increase in magnetostriction.

  8. Micro-Plasto-Hydrodynamic Lubrication a Fundamental Mechanism in Cold Rolling

    DEFF Research Database (Denmark)

    Laugier, Maxime; Boman, Romain; Legrand, Nicolas

    2014-01-01

    This paper presents recent investigations in Micro-Plasto-Hydrodynamic (MPH) lubrication. Industrial evidences of the existence of MPH lubrication mechanism for cold rolling processes are presented. A new lubrication model developed for strip drawing processes is then applied to predict the MPH...... lubrication initiation and MPH lubrication extension along the tool-piece solid contacts initially in boundary lubrication regime. Finally, it is shown how this new MPH lubrication model can be implemented in a cold rolling model to maximize mills capabilities, determine optimum rolling oils properties...

  9. Online application of automatic surface quality inspection system to finishing line of cold rolled strips

    Institute of Scientific and Technical Information of China (English)

    Hao Sun; Ke Xu; Jinwu Xu

    2003-01-01

    An autonatic surface quality inspection system installed on a finishing line of cold rolled strips is introduced. The system is able to detect surface defects on cold rolled strips, such as scratches, coil breaks, rusts, roll imprints, and so on. Multiple CCD area scan canteras were equipped to capture images of strip surface simultaneously. Defects were detected through "Dark-field illumination' which is generated by LED illuminators. Parallel computation technique and fast processing algorithms were developed for real-time data processing. The application to the production line shows that the system is able to detect defects effectively.

  10. Improving Thin Strip Profile Using Work Roll Cross and Work Roll Shifting Methods in Cold Strip Rolling

    Directory of Open Access Journals (Sweden)

    Hasan Tibar

    2017-01-01

    Full Text Available The optimization of rolling parameters in order to achieve better strip shape and to reduce rolling force is a challenge in rolling practice. In this paper, thin strip asymmetrical rolling of aluminum at various speed ratios under lubricated condition has been investigated at various combinations of work rolls cross (WRC angles and work rolls shifting (WRS values. The effects of strip width, reduction, and rolling speed on strip shape taking WRC and WRS into consideration are discussed. Results show that strip profile improves significantly when the WRC angle is increased from 0° to 1°, with an associated reduction in rolling force. Increasing WRS value from 0 to 8 mm improves the strip profile as well but not as significantly as when WRC angle is increased. No significant improvement was found in strip shape when the strip width was increased. At higher reduction, the strip shape was improved; a decrease in the rolling force was also observed. A higher speed ratio was found to be effective only at a higher WRC angle. The effect of lubrication on the strip profile was significant. Results indicate that an optimum combination of WRC, WRS, reduction, width, and speed ratio under lubricated conditions can ensure an improved exit strip profile, reduce rolling force, and obtain a better quality strip.

  11. Force prediction in cold rolling mills by polynomial methods

    Directory of Open Access Journals (Sweden)

    Nicu ROMAN

    2007-12-01

    Full Text Available A method for steel and aluminium strip thickness control is provided including a new technique for predictive rolling force estimation method by statistic model based on polynomial techniques.

  12. TOOTH CURVES AND ENTIRE CONTACT AREA IN PROCESS OF SPLINE COLD ROLLING

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In spline rolling process, the contact area between roller and workpiece plays an important role in calculating rolling-force and rolling-moment. For the purpose of studying the contact area, contact state between roller and workpiece in process of spline cold rolling based upon cross rolling is analyzed. According to the suitable hypothesis, the mathematic model of roller-tooth-curve in optional position of rolling process is established. Combing the theory of conjugate curves with the theory of envelope curve, the corresponding mathematic model of workpiece-tooth-curve is established. By utilizing establishing mathematic models, the algorithm of entire contact area in rolling process is created. On the basis of the algorithm, calculation-program is compiled under MATLAB program language environment. The calculation-program actualizes quantitative analysis and quantitative calculation of contact areas. Utilizing the calculation-program, the influence of parameters on contact area is analyzed, and the tendency is consistent with the manufacturing experience. In consideration of rolling-force optimization, the primary process parameters may be selected according to results of calculation. The result of the present study may provide basis for research on rolling-force and rolling-moment.

  13. Effects of recrystallization annealing on mechanical properties of cold-rolled PdNi5 wires

    Directory of Open Access Journals (Sweden)

    Aleksandra Ivanović

    2016-03-01

    Full Text Available The aim of this investigation was to determine the influence of the recrystallization temperature and recrystallization time on the microstructure and mechanical properties of the PdNi5 alloy subjected to cold deformation in the process of rolling at a constant deformation degree. The samples of PdNi5 alloy were recrystallization annealed within the temperature range of 200-1000ºC and annealing time range of 20-45 min after cold rolling with deformation degree of 97%. The tensile test was carried out using universal material testing machine. The hardness was also measured on the combined device for measuring Vickers and Brinell hardness. Metallographic observations were performed on an optical microscope. The analysis of the results of investigations regarding the microstructural changes and corresponding mechanical properties of cold-rolled PdNi5 strips shows that annealing temperature of 500ºC was sufficient to activate the energy for various recrystallization processes causing a change in the mechanical properties of cold-rolled PdNi5 strips. The annealing time, at constant annealing temperature, almost did not affect a recrystallization temperature and the mechanical properties of the cold-rolled PdNi5 strips.

  14. Surface Improvement of Shafts by Turn-Assisted Deep Cold Rolling Process

    Directory of Open Access Journals (Sweden)

    Prabhu Raghavendra

    2016-01-01

    Full Text Available It is well recognized that mechanical surface enhancement methods can significantly improve the characteristics of highly-stressed metallic components. Deep cold rolling is one of such technique which is particularly attractive since it is possible to generate, near the surface, deep compressive residual stresses and work hardened layers while retaining a relatively smooth surface finish. In this paper, the effect of turn-assisted deep cold rolling on AISI 4140 steel is examined, with emphasis on the residual stress state. Based on the X-ray diffraction measurements, it is found that turn-assisted deep cold rolling can be quite effective in retarding the initiation and initial propagation of fatigue cracks in AISI 4140 steel.

  15. Shear-Coupled Grain Growth and Texture Development in a Nanocrystalline Ni-Fe Alloy during Cold Rolling

    Science.gov (United States)

    Li, Li; Ungár, Tamás; Toth, Laszlo S.; Skrotzki, Werner; Wang, Yan Dong; Ren, Yang; Choo, Hahn; Fogarassy, Zsolt; Zhou, X. T.; Liaw, Peter K.

    2016-12-01

    The evolution of texture, grain size, grain shape, dislocation, and twin density has been determined by synchrotron X-ray diffraction and line profile analysis in a nanocrystalline Ni-Fe alloy after cold rolling along different directions related to the initial fiber and the long axis of grains. The texture evolution has been simulated by the Taylor-type relaxed-constraints viscoplastic polycrystal model. The simulations were based on the activity of partial dislocations in correlation with the experimental results of dislocation density determination. The concept of stress-induced shear coupling is supported and strengthened by both the texture simulations and the experimentally determined evolution of the microstructure parameters. Grain growth and texture evolution are shown to proceed by the shear coupling mechanism supported by dislocation activity as long as the grain size is not smaller than about 20 nm.

  16. Kinetics of individual grains during recrystallization of cold-rolled copper

    DEFF Research Database (Denmark)

    Lin, Fengxiang; Zhang, Yubin; Poulsen, S.O.;

    2015-01-01

    The formation of a recrystallization texture is closely related to the nucleation and growth of recrystallizing grains, which may vary from grain to grain. Cube texture is a commonly observed recrystallization texture in face centered cubic metals of medium to high stacking fault energy after heavy...... cold-rolling and annealing. In this work, recrystallization of pure copper cold-rolled to a von Mises strain of 2.7 was investigated in situ using three-dimensional X-ray diffraction. Growth curves of 835 grains were determined, and the curves of cube and non-cube grains were compared. It was found...

  17. High Precision Prediction of Rolling Force Based on Fuzzy and Nerve Method for Cold Tandem Mill

    Institute of Scientific and Technical Information of China (English)

    JIA Chun-yu; SHAN Xiu-ying; NIU Zhao-ping

    2008-01-01

    The rolling force model for cold tandem mill was put forward by using the Elman dynamic recursive network method, based on the actual measured data. Furthermore, a good assumption is put forward, which brings a full universe of discourse self-adjusting factor fuzzy control, closed-loop adjusting, based on error feedback and expertise into a rolling force prediction model, to modify prediction outputs and improve prediction precision and robustness. The simulated results indicate that the method is highly effective and the prediction precision is better than that of the traditional method. Predicted relative error is less than ±4%, so the prediction is high precise for the cold tandem mill.

  18. Formation of Copper Type Texture in Cold Rolled Aluminum Sheet

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The formation process of copper type rolling texture in f.c.c. Metals was simulated based on a deformation modelconsidering internal reaction stresses induced by the neighboring matrix as well as external shear stress induced byrollers. It is indicated that the external shear stress will reduce the brass type texture and increase the copper typetexture obviously.

  19. Simulation and Analysis on Void Evolution during Stretching Process of Super Carbon Steel Cold Rolls%高碳钢冷轧辊拔长过程内部孔洞演变模拟分析

    Institute of Scientific and Technical Information of China (English)

    陈文琳; 高妍; 李伟

    2014-01-01

    目的:研究拔长锻造过程中,不同的工艺参数对锻件内部孔洞闭合效果的影响。方法采用数值模拟的方法,研究了高碳钢冷轧辊拔锻坯在拔长锻造过程中,下砧宽、压下量、送进量等关键工艺参数对锻坯内部孔洞闭合效果及应力应变分布状态的影响。结果3个工艺参数都对锻件心部质量及内部应力应变状态有影响。结论有效压实心部疏松缺陷的最佳砧宽为200 mm;采用每次压下量基本一致的工艺方案,即每次压下率保持在17%左右,可保证锻件变形均匀,从而获得较好的心部质量;相对送进量为0.8时,有利于心部孔洞的锻合。%Objective To study the effects of forming parameters on the cavity closure of the forgings. Methods The in-fluences of anvil width, reduction, and feed on the cavity closure and distribution of strain were simulated in the stretching process of super carbon steel cold rolls. Results All three forming parameters had influences on the internal quality and dis-tribution of strain of the forgings. Conclusion The best anvil width for the compaction effect was 200 mm; a uniform reduc-tion of 17% could result in much more uniform deformation and better internal quality; the optimal relative feed for impro-ving cavity closure was 0. 8.

  20. Microstructure and Property Modifications of Cold Rolled IF Steel by Local Laser Annealing

    Science.gov (United States)

    Hallberg, Håkan; Adamski, Frédéric; Baïz, Sarah; Castelnau, Olivier

    2017-07-01

    Laser annealing experiments are performed on cold rolled IF steel whereby highly localized microstructure and property modification are achieved. The microstructure is seen to develop by strongly heterogeneous recrystallization to provide steep gradients, across the submillimeter scale, of grain size and crystallographic texture. Hardness mapping by microindentation is used to reveal the corresponding gradients in macroscopic properties. A 2D level set model of the microstructure development is established as a tool to further optimize the method and to investigate, for example, the development of grain size variations due to the strong and transient thermal gradient. Particular focus is given to the evolution of the beneficial γ-fiber texture during laser annealing. The simulations indicate that the influence of selective growth based on anisotropic grain boundary properties only has a minor effect on texture evolution compared to heterogeneous stored energy, temperature variations, and nucleation conditions. It is also shown that although the α-fiber has an initial frequency advantage, the higher probability of γ-nucleation, in combination with a higher stored energy driving force in this fiber, promotes a stronger presence of the γ-fiber as also observed in experiments.

  1. Microstructure and Property Modifications of Cold Rolled IF Steel by Local Laser Annealing

    Science.gov (United States)

    Hallberg, Håkan; Adamski, Frédéric; Baïz, Sarah; Castelnau, Olivier

    2017-10-01

    Laser annealing experiments are performed on cold rolled IF steel whereby highly localized microstructure and property modification are achieved. The microstructure is seen to develop by strongly heterogeneous recrystallization to provide steep gradients, across the submillimeter scale, of grain size and crystallographic texture. Hardness mapping by microindentation is used to reveal the corresponding gradients in macroscopic properties. A 2D level set model of the microstructure development is established as a tool to further optimize the method and to investigate, for example, the development of grain size variations due to the strong and transient thermal gradient. Particular focus is given to the evolution of the beneficial γ-fiber texture during laser annealing. The simulations indicate that the influence of selective growth based on anisotropic grain boundary properties only has a minor effect on texture evolution compared to heterogeneous stored energy, temperature variations, and nucleation conditions. It is also shown that although the α-fiber has an initial frequency advantage, the higher probability of γ-nucleation, in combination with a higher stored energy driving force in this fiber, promotes a stronger presence of the γ-fiber as also observed in experiments.

  2. Effect of Cold-Rolling on Precipitation Phenomena in Sensitized Type 316L and 340L Austenitic Stainless Steels

    Institute of Scientific and Technical Information of China (English)

    H.Tsubakino; A.Yamamoto; T. Yamada; L.Liu; M.Terasawa; S.Nakahigashi; H.Harada

    2004-01-01

    Precipitation phenomena in Type 316L and 304L stainless steels were studied mainly by transmission electron microscopic (TEM) observations after cold-rolling ranging from 0% (as solution annealed) to 80% reduction in thickness,and then by sensitization treatment. Precipitates were identified by electron diffraction analysis and EDS analysis.Precipitates observed in sensitized 316L stainless steel were sigma and chi phases, whereas carbide and sigma were observed in sensitized 304L stainless steel. Recrystallized grains were formed in 30% cold-rolled and sensitized 304L.However, the tendency toward recrystallization in sensitized 316L was much lower than in 304L. Precipitation of sigma and chi phases was accelerated by cold-rolling and they were observed at grain boundaries in lower cold-rolling; they were also seen, in grain interiors in higher cold-rolling. Higher deformation induced partially recrystallization combined with precipitation, resulting in the formation of heterogeneous microstructures.

  3. Effect of cold rolling on properties and microstructures of dispersion strengthened copper alloys

    Institute of Scientific and Technical Information of China (English)

    GUO Ming-xing; WANG Ming-pu; SHEN Kun; CAO Ling-fei; LEI Ruo-shan; LI Shu-mei

    2008-01-01

    Mechanical properties and microstructures of unidirectionally and tandem rolled alumina dispersion strengthened copper(ADSC) alloys under different conditions were investigated by tensile test, optical microscopy(OM), transmission electron microscopy(TEM) and scanning electron microscopy(SEM). For unidirectionally rolled ADSC alloys, their strengths and elongations in the longitudinal direction are higher than those in the transverse direction under both cold rolling and annealing conditions. Once fracture appears in their longitudinal stress-strain curves, sudden reduction of overall stress level before complete fracture can be observed in the transverse tensile curves. The anisotropy of mechanical properties for the ADSC alloy can be greatly improved by tandem cold rolling. And no sudden reduction of overall stress level appears in the stress-strain curves for tandem rolled ADSC alloys. The differences of their microstructures and tensile fractures were analyzed. In order to compare the differences of tensile fracture mechanism in different directions, longitudinal and transverse fracture models for unidirectionally rolled ADSC alloys were also introduced.

  4. High-precision Thickness Setting Models for Titanium Alloy Plate Cold Rolling without Tension

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaochen; YANG Quan; HE Fei; SUN Youzhao; XIAO Huifang

    2015-01-01

    Due to its highly favorable physical and chemical properties, titanium and titanium alloy are widely used in a variety of industries. Because of the low output of a single batch, plate cold rolling without tension is the most common rolling production method for titanium alloy. This method is lack of on-line thickness closed-loop control, with carefully thickness setting models for precision. A set of high-precision thickness setting models are proposed to suit the production method. Because of frequent variations in rolling specification, a model structural for the combination of analytical models and statistical models is adopted to replace the traditional self-learning method. The deformation resistance and friction factor, the primary factors which affect model precision, are considered as the objectives of statistical modeling. Firstly, the coefficient fitting of deformation resistance analytical model based on over-determined equations set is adopted. Additionally, a support vector machine(SVM) is applied to the modeling of the deformation resistance and friction factor. The setting models are applied to a 1450 plate-coiling mill for titanium alloy plate rolling, and then thickness precision is found consistently to be within 3%, exceeding the precision of traditional setting models with a self-learning method based on a large number of stable rolling data. Excellent application performance is obtained. The proposed research provides a set of high-precision thickness setting models which are well adapted to the characteristics of titanium alloy plate cold rolling without tension.

  5. High-precision thickness setting models for titanium alloy plate cold rolling without tension

    Science.gov (United States)

    Wang, Xiaochen; Yang, Quan; He, Fei; Sun, Youzhao; Xiao, Huifang

    2015-03-01

    Due to its highly favorable physical and chemical properties, titanium and titanium alloy are widely used in a variety of industries. Because of the low output of a single batch, plate cold rolling without tension is the most common rolling production method for titanium alloy. This method is lack of on-line thickness closed-loop control, with carefully thickness setting models for precision. A set of high-precision thickness setting models are proposed to suit the production method. Because of frequent variations in rolling specification, a model structural for the combination of analytical models and statistical models is adopted to replace the traditional self-learning method. The deformation resistance and friction factor, the primary factors which affect model precision, are considered as the objectives of statistical modeling. Firstly, the coefficient fitting of deformation resistance analytical model based on over-determined equations set is adopted. Additionally, a support vector machine(SVM) is applied to the modeling of the deformation resistance and friction factor. The setting models are applied to a 1450 plate-coiling mill for titanium alloy plate rolling, and then thickness precision is found consistently to be within 3%, exceeding the precision of traditional setting models with a self-learning method based on a large number of stable rolling data. Excellent application performance is obtained. The proposed research provides a set of high-precision thickness setting models which are well adapted to the characteristics of titanium alloy plate cold rolling without tension.

  6. INFLUENCE OF SURFACE DEFECTS, INHERITED FROM ROLLED WIRE, ON QUALITY OF A COLD-DRAWN WIRE

    Directory of Open Access Journals (Sweden)

    A. N. Savenok

    2012-01-01

    Full Text Available Researches of the most often occurred surface defects of rolled wires, their modification at drawing and influence on technological process and quality of cold-drawn wire with regard to working conditions of hardware shops of OAO “BMZ” are  presented.

  7. INFLUENCE OF THE SURFACE DEFECTS INHERITED FROM ROLLED WIRE ON QUALITY OF COLD DRAWN WIRE

    Directory of Open Access Journals (Sweden)

    A. N. Savenok

    2012-01-01

    Full Text Available Researches of the most often occurred surface defects of rolled wires, their modification at drawing and influence on technological process and quality of cold-drawn wire with regard to working conditions of hardware shops of BMZ are presented.

  8. Formation of a random recrystallization texture in heavily cold rolled and annealed Al-1%Si alloy

    DEFF Research Database (Denmark)

    Chen, Y.L.; Huang, T.L.; Gong, X.;

    2013-01-01

    An Al-1%Si alloy cold rolled to a von Mises stain of 4.5 was isothermally annealed at 210°C. A random recrystallization texture was obtained, which was attributed to the effects of particles of different sizes on the nucleation and growth of grains during recrystallization. © (2013) Trans Tech Pu...

  9. Fracture Behavior of TiNi Based Shape Memory Alloy Cold-rolled Tube

    Institute of Scientific and Technical Information of China (English)

    LI Yan-wu; LIU Fu-shun

    2006-01-01

    The microstructures and interfacial characteristics of matrices at the inwalls and the out-walls of the cold-rolled tube with different amounts of deformation were investigated by the scanning electronic microscope (SEM), the optical microscope (OM), and the transmission electronic microscope (TEM) techniques. It was observed that as the amount of deformation increases, the flaws nucleate at the out-walls of the cold rolled tube, the stress-induced martensites change from (11) type Ⅰ twins to (011) type Ⅱ twins and then to (100) compound twins, nanocrystals and bulk amorphisation happen, the high density dislocation causes stress concentration at the out-walls of the Ti50Ni50 cold-rolled tube, and then precipitates its fracture, and the Ti2Ni particles strengthen the grain boundaries and curb the dislocation movements during plastic deformation. The inhomogeneity level of the grains in the Ti50Ni50 alloy plays an important role on the fracture of the Ti50Ni50 cold rolled tube.

  10. The effects of cold rolling and heat treatment on Al 6063 reinforced with silicon carbide granules

    Science.gov (United States)

    Balogun, S. A.; Adeosun, S. O.; Sanni, O. S.

    2009-08-01

    The effects of cold rolling and heat treatment on the strength and ductility of aluminum alloy 6063 reinforced with silicon carbide granules have been examined. Silicon carbide (SiCp) 100 μm grain size was added to 6063 aluminum in volume fractions of 0-30% to produce samples for heat treatment and cold rolling. The results show that an optimum combination of strength and ductility at 137.92 MPa and true strain of 0.173 is achievable with rolled-and-tempered samples containing 10% SiCp. This is a significant improvement on 6063 aluminum alloy having an ultimate tensile strength of ˜100 MPa at true strain of 0.18.

  11. Grain structure evolution during cryogenic rolling of alpha brass

    Energy Technology Data Exchange (ETDEWEB)

    Konkova, T. [Institute for Metals Superplasticity Problems, Rssian Academy of Science, 39 Khalturin Str., Ufa 450001 (Russian Federation); Mironov, S. [Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-aza-Aoba, Sendai 980-8579 (Japan); Korznikov, A. [Institute for Metals Superplasticity Problems, Rssian Academy of Science, 39 Khalturin Str., Ufa 450001 (Russian Federation); National Research Tomsk State University, 36 Lenina av., Tomsk 634050 (Russian Federation); Korznikova, G. [Institute for Metals Superplasticity Problems, Rssian Academy of Science, 39 Khalturin Str., Ufa 450001 (Russian Federation); Myshlyaev, M.M. [Baikov Institute of Metallurgy and Material Science, Russian Academy of Science, 49 Lenin-av., Moscow 119991 (Russian Federation); Semiatin, S.L. [Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RXCM, Wright-Patterson AFB, OH 45433-7817 (United States)

    2015-04-25

    Highlights: • Cryogenic rolling produced inhomogeneous ultrafine-grained microstructure. • Grain refinement was mainly related with twinning and shear banding. • Grain refinement preferentially occurred in Copper {1 1 0}(1 1 2) grains. - Abstract: High-resolution electron backscatter diffraction (EBSD) was used to study grain structure development during cryogenic rolling of Cu–29.5Zn brass. Microstructure evolution was found to be broadly similar to that occurring during rolling at room temperature. Specifically, favorably-oriented grains (Copper {1 1 2}(1 1 1) and S {1 2 3}(6 3 4)) experienced profuse deformation twinning followed by extensive shear banding. This eventually produced an ultrafine structure with a mean grain size of ~0.2 μm. On the other hand, grains with crystallographic orientations close to Brass {1 1 0}(1 1 2) and Goss {1 1 0}(1 0 0) were found to be stable against twinning/shear banding and thus showed no significant grain refinement. As a result, the final structure developed in heavily-rolled material was distinctly inhomogeneous consisting of mm-scale remnants of original grains with poorly developed substructure and ultra-fine grain domains.

  12. Dislocation Boundary Structure from Low to Medium Strain of Cold Rolling AA3104 Aluminum Alloy

    Science.gov (United States)

    Yao, Zongyong; Huang, Guangjie; Godfrey, Andrew; Liu, Wei; Liu, Qing

    2009-06-01

    The evolution of the dislocation boundary structure during the cold rolling of the AA3104 aluminum alloy has been investigated using electron channeling contrast (ECC) imaging and electron backscattered diffraction (EBSD) techniques. The results show that there is a strong correlation between the dislocation boundary structure and the grain orientation. No strong effect of strain level or second-phase particles on the structure-orientation correlation is found. Based on these observations, the microstructures can be classified into one of three types: type A grains, containing two sets of geometrically necessary boundaries (GNBs), type B grains, containing one set of GNBs, and type C grains, consisting of a structure of large dislocation cells. Grains with a type A microstructure have orientations near the copper, brass, and Goss orientations; grains with a type B microstructure are primarily near the S orientation; and grains with a type C microstructure have orientations near the cube orientation. The alignment of the extended dislocation boundaries depends strongly on the grain orientation. In most grains, the boundaries are parallel to the traces of the most active {111} slip planes, as identified by a Schmid factor analysis.

  13. Calculation of Crystallographic Texture of BCC Steels During Cold Rolling

    Science.gov (United States)

    Das, Arpan

    2017-05-01

    BCC alloys commonly tend to develop strong fibre textures and often represent as isointensity diagrams in φ 1 sections or by fibre diagrams. Alpha fibre in bcc steels is generally characterised by crystallographic axis parallel to the rolling direction. The objective of present research is to correlate carbon content, carbide dispersion, rolling reduction, Euler angles (ϕ) (when φ 1 = 0° and φ 2 = 45° along alpha fibre) and the resulting alpha fibre texture orientation intensity. In the present research, Bayesian neural computation has been employed to correlate these and compare with the existing feed-forward neural network model comprehensively. Excellent match to the measured texture data within the bounding box of texture training data set has been already predicted through the feed-forward neural network model by other researchers. Feed-forward neural network prediction outside the bounds of training texture data showed deviations from the expected values. Currently, Bayesian computation has been similarly applied to confirm that the predictions are reasonable in the context of basic metallurgical principles, and matched better outside the bounds of training texture data set than the reported feed-forward neural network. Bayesian computation puts error bars on predicted values and allows significance of each individual parameters to be estimated. Additionally, it is also possible by Bayesian computation to estimate the isolated influence of particular variable such as carbon concentration, which exactly cannot in practice be varied independently. This shows the ability of the Bayesian neural network to examine the new phenomenon in situations where the data cannot be accessed through experiments.

  14. Mathematical model for strip surface roughness of stainless steel in cold rolling process

    Science.gov (United States)

    Chen, Jinshan; Li, Changsheng; Zhu, Tao; Han, Wenlong; Cao, Yong

    2013-05-01

    Surface roughness control is one of the most important subjects during producing stainless steel strips. In this paper, under the conditions of introducing to the concepts of transferring ratio and genetic factor and through the further theoretical analysis, a set of theoretical models about strip surface roughness were put forward in stainless steel cold tandem rolling. Meanwhile, the lubrication experiment in cold rolling process of SUS430 stainless steel strip was carried out in order to comprehensively study surface roughness. The effect of main factors on transferring ratio and genetic factor was analyzed quantitatively, such as reduction, initial thickness, deformation resistance, emulsion technological parameters and so on. Attenuation function equations used for describing roll surface roughness were set up, and also strip surface roughness at the entry of last mill was solved approximately. Ultimately, mathematical model on strip surface roughness for cold tandem rolling of stainless steel was built, and then it was used into the practical production. A great number of statistical results show that experimental data is in excellent agreement with the given regression equations, and exactly, the relative deviation on roughness between calculated and measured is less than 6.34%.

  15. B3 Spline Function Method Used in Simulating Flatness and Profile of Cold Rolled Strip

    Institute of Scientific and Technical Information of China (English)

    LI Jun-hong; QI Xiang-dong; LIAN Jia-chuang

    2004-01-01

    Flatness and profile are important quality indexes of strip. Combining the influence function method to solve the elastic deformation of roll system with the variational method to solve the lateral flow of metal, the flatness and profile of the strip during cold continuous rolling were simulated. The B3 spline function was used to analogize the lateral distribution of strip thickness. The transverse distributions of the exit thickness and the front tension stress for each pass were obtained. Compared with the measured results, it is proved that using the spline function to analogize the lateral distribution of strip thickness can improve the calculation accuracy of flatness and profile largely.

  16. Reduction of Anisotropy in Cold-Rolled Duplex Stainless Steel Sheets by Using Sigma Phase Transformation

    Science.gov (United States)

    Fargas, G.; Akdut, N.; Anglada, M.; Mateo, A.

    2011-11-01

    The mechanical properties of rolled duplex stainless steel (DSS) products manufactured by the current industrial process exhibit a strong anisotropy. This fact is evidently due to the two-phase nature of DSSs. During industrial rolling, not only the morphology of the microstructure changes from coarse-grained isotropic in the cast slab to fine-grained anisotropic in the coil, with both phases elongated in the rolling direction (RD), but also clear and intense crystallographic rolling textures develop, especially in the ferritic phase. The objective of the present work was to modify the industrial processing route and parameters in such a way that the strong anisotropy of DSS coils and sheets is decreased and the amount of potential applications made from DSSs by deep drawing or roll forming operations is increased. To achieve this goal, after the industrial cold rolling, a heat treatment is proposed with the aim of modifying the morphology and crystallographic texture of the ferritic grains by the assistance of an enforced transformation to sigma phase. The final product obtained by this modified route showed a microstructure with grains of austenite and ferrite randomly distributed and a significant decrease of the texture intensities due to the retransformation of sigma into ferrite. As a result, DSS EN 1.4462 displayed an almost isotropic mechanical behavior and an improved aptitude to deep drawing operations.

  17. Robust Backstepping Control for Cold Rolling Main Drive System with Nonlinear Uncertainties

    Directory of Open Access Journals (Sweden)

    Xu Yang

    2013-01-01

    Full Text Available The nonlinear model of main drive system in cold rolling process, which considers the influence with parameter uncertainties such as clearance and variable friction coefficient, as well as external disturbance by roll eccentricity and variation of strip material quality, is built. By transformation, the lower triangular structure form of main drive system is obtained. The backstepping algorithm based on signal compensation is proposed to design a linear time-invariant (LTI robust controller, including a nominal controller and a robust compensator. A comparison with PI controller shows that the controller has better disturbance attenuation performance and tracking behaviors. Meanwhile, according to its LTI characteristic, the robust controller can be realized easily; therefore it is also appropriated to high speed dynamic rolling process.

  18. Stainless Steel Microstructural Evolution of Hot-Rolled Clad Plate

    Directory of Open Access Journals (Sweden)

    Hai-Bin LI

    2016-11-01

    Full Text Available The stainless steel microstructure evolution of carbon–stainless-clad steel plate was investigated during vacuum hot-rolling bonding under different deformation conditions. The results show that carbide M2C precipitates in the interior of stainless steel (SS and carbon content increases with rising reduction ratio (ε. The dislocation density of the SS surface (ρI is lower than that of the midst (ρM, and ρI decreases with the rising ε. However, ρM increases first and then decreases with rising ε. The dislocation density of bonding interface decreases due to the increasing size of austenite grain. Furthermore, the dislocation density of the midst is high where the high energy of carbide M2C is concentrated for single-pass rolling, and the quantity of M2C increases with reduction ratio. Moreover, carbide almost disappeared while being transformed into austenite, and only minimal granular carbides were formed after two-pass rolling. Bonding strength increases evidently with rising ε and is inversely proportional to ρI.DOI: http://dx.doi.org/10.5755/j01.ms.22.4.12828

  19. INFLUENCE OF COLD ROLLING REDUCTION ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF TWIP STEEL

    Institute of Scientific and Technical Information of China (English)

    Z.L. Mi; D. Tang; Y.J. Dai; H.Q. Wang; S.S. Li

    2007-01-01

    The influence of cold rolling reduction on microstructure and mechanical properties of the TWIP (ttwinning induced plasticity) steel was investigated. The results indicated that the steel had better comprehensive mechanical properties when cold rolling reduction was about 65.0% and the annealing temperature was 1000℃. The tensile strength of the steel is about 640MPa and the yield strength is higher than 255MPa, while the elongation is above 82%. The microstructure is composed of austenitic matrix and annealing twins at room temperature, at the same time, a significant amount of annealing twins and stacking faults are observed by transmission electron microscopy (TEM). Mechanical twins play a dominant role during deformation, and result in excellent mechanical properties.

  20. In Search of the Attributes Responsible for Sliver Formation in Cold Rolled Steel Sheets

    Science.gov (United States)

    Mohanty, Itishree; Das, Prasun; Bhattacharjee, Debashish; Datta, Shubhabrata

    2016-06-01

    Surface quality is one of the most important characteristics of cold rolled (CR) steel sheets for its application in consumer goods industries. The actual cause of sliver formation is very difficult to determine, as it is revealed only after the final cold rolling of the steel. A thorough investigation on searching the root cause of sliver formation in CR steel is done here using several statistical tools towards mining the industrial data for extraction of knowledge. As the complex interactions between the variables make it difficult to identify the cause, it is seen that findings from different techniques differed to a certain extent. Still it is revealed that 21 variables could be short listed as major contributor for sliver formation, but those are found to be from all the areas of the processing. This leads to the conclusion that no particular process variable or particular processing could be held responsible for sliver formation.

  1. Synthesis, Characterization and Tribological Evaluation of New Generation Materials for Aluminum Cold Rolling Oils

    Directory of Open Access Journals (Sweden)

    Ponnekanti Nagendramma

    2016-06-01

    Full Text Available The present concept of being globally “green” puts additional demands on lubricants. They are to be biodegradable and ecofriendly. Therefore, in a search for alternate lubricants meeting the above demands, we have synthesized biodegradable new generation esters using alcohols such as 2,2-dimethyl-1,3-propane diol and 2,2-diethyl-1,3-propane diol and fatty acids like caproic and 2-ethyl caproic in presence of indigenous ion exchange resin catalyst. The synthesized esters were analyzed and characterized for their physico chemical properties. In addition, with a view to finding out the possibility of using these esters as aluminum cold rolling oils, their lubricity characteristics, biodegradability and toxicity were also investigated. The products were found to have good potential for use in biodegradable aluminum cold rolling oils meeting IS: 14385-2002 specification.

  2. Influence of cold rolling degree and ageing treatments on the precipitation hardening of 2024 and 7075 alloys

    Science.gov (United States)

    Naimi, A.; Yousfi, H.; Trari, M.

    2013-08-01

    In the present work, the precipitation hardening of 2024 and 7075 aluminum alloys is investigated as a function of cold rolling degree, ageing time and temperature using Vickers microhardness measurements and differential scanning calorimetry (DSC). It is found that a variation in such parameters can improve the hardness and plays an important role in the precipitation hardening process. At specific ageing temperature, the large cold rolled 7075 alloy exhibits two peaks of hardness. Moreover, for both alloys, the increment of hardness during ageing decreases with increasing the cold rolling degree. While in some cases microhardness measurements give impression that the precipitation reaction is slowed down by deformation, DSC analysis indicates that the precipitation is much accelerated since only a slight deformation decreases strongly the temperatures of reactions. However, the degree of cold rolling does not play a crucial role.

  3. Recrystallization Texture Transition in Fe-2.1 Wt Pct Si Steel by Different Cold Rolling Reduction

    Science.gov (United States)

    Shan, Ning; Sha, Yuhui; Zhang, Fang; Liu, Jinlong; Zuo, Liang

    2016-12-01

    The competition dependent on cold rolling reduction among main recrystallization texture components in Fe-2.1 wt pct Si sheets was investigated from the hot band characterized by strong Cube ({001}) at center layer and weak Goss ({110}) at quarter layer. The deformation and recrystallization textures through thickness were both analyzed by X-ray diffraction technique. Goss, Cube, and {111} components dominate the recrystallization texture in sequence with the cold rolling reduction increasing from 60 to 90 pct. This recrystallization texture transition with cold rolling reduction can be explained in terms of the number and nature of nucleation sites for various texture components. A variety of final recrystallization textures are proposed for non-oriented silicon steel by designing texture and microstructure of hot band and cold rolling reduction.

  4. Effect of cold rolling on the hydrogen absorption and desorption kinetics of Zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Dupim, I.S.; Moreira, J.M.L. [CESC, Universidade Federal do ABC, Av. dos Estados 5001, CEP: 09210-580 Santo André, SP (Brazil); Huot, J. [IRH, Université du Québec à Trois Rivières, 3351 boul. des Forges, CP 500, G9Y5H7 Trois Rivières, QC (Canada); Santos, S.F., E-mail: sydney.ferreira@ufabc.edu.br [CESC, Universidade Federal do ABC, Av. dos Estados 5001, CEP: 09210-580 Santo André, SP (Brazil)

    2015-04-01

    Metal matrix composites have been considered promising candidates as nuclear fuels for pressurized water reactors and also for nuclear waste management. Among others, Zircaloy is considered an excellent alternative for metallic matrix in such composites due to its excellent mechanical properties, high thermal conductivity and high corrosion resistance at operating temperatures. For manufacturing these fuels, a necessary step is the production of Zircaloy powder to be used as raw material. A feasible route to produce powders of refractory metals and alloys like Zircaloy is the hydriding and dehydriding process. For this type of processing route, hydrogen absorption and desorption should be performed at the lowest temperature and pressure possible in order to reduce the processing costs. In this paper, we investigated the hydrogen sorption kinetics of Zircaloy and the effect of cold rolling on the reaction rate. It was found that cold rolling greatly increases the hydrogenation kinetics and drastically reduces the dehydrogenation temperature. - Highlights: • The effects of temperature and pressure on the hydrogen reaction kinetics in Zircaloy-4 are analyzed. • The incubation time during absorption measurements increased for higher H2 pressures. • Changes in hydriding reaction kinetics at 1500 kPa of H{sub 2} and 1.25 wt.% of absorption. • Cold rolling increased the hydrogen absorption kinetics and decreased the hydride decomposition temperature.

  5. Reduced-order observer-based robust synchronisation control of cold rolling mills with measurement delay

    Science.gov (United States)

    Jiao, Xiaohong; Mei, Zhisong

    2010-10-01

    To improve the quality of strip thickness, synchronisation control is investigated for cold rolling mills driven by dual-cylinder electro-hydraulic servo systems. Realising synchronised control in hydraulic automatic gauge control (HAGC) systems of cold rolling mills has challenges with not only the inherent nonlinearities of hydraulic servo systems and uncertainties of load variation but also measurement delay of strip thickness. Since all states are not measurable in practice, output feedback robust synchronisation control problem should be addressed for uncertain nonlinear systems with output delay. Thus, a reduced-order observer-based robust synchronous controller is presented by employing Lyapunov functional stability theory. The controller designed by incorporating the integral of the position synchronisation error of two pistons into state variables successfully guarantees asymptotic convergence to zero of both tracking errors and synchronisation error simultaneously regardless of the nonlinearities and uncertainties as well as the measurement delay. Simulation results in a model obtained from a real cold strip rolling mill demonstrate the effectiveness of the approach.

  6. Deformation mechanism of cold ring rolling in view of texture evolution predicted by a newly proposed polycrystal plasticity model%基于新晶体塑性模型预测织构演化的环件冷轧变形机制

    Institute of Scientific and Technical Information of China (English)

    李宏伟; 冯璐; 杨合

    2013-01-01

    An explicit polycrystal plasticity model was proposed to investigate the deformation mechanism of cold ring rolling in view of texture evolution. The model was created by deducing a set of linear incremental controlling equations within the framework of crystal plasticity theory. It was directly solved by a linear algorithm within a two-level procedure so that its efficiency and stability were guaranteed. A subroutine VUMAT for ABAQUS/Explicit was developed to combine this model with the 3D FE model of cold ring rolling. Results indicate that the model is reliable in predictions of stress-strain response and texture evolution in the dynamic complicated forming process; the shear strain in RD of the ring is the critical deformation mode according to the sharp Goss component ({110}〈100〉) of deformed ring; texture and crystallographic structure of the ring blank do not affect texture type of the deformed ring;texture evolves rapidly at the later stage of rolling, which results in a dramatically increasing deformation of the ring.%提出一种新的多晶体塑性模型以从织构演化角度研究环件冷轧过程的变形机制。该模型是在晶体塑性理论框架内通过推导一套线性增量控制方程建立的。该模型可以用线性求解方法直接求解,并采用一个两步法的求解过程,确保模型计算的效率和稳定性。基于ABAQUS/Explicit平台开发了用户材料子程序VUMAT,以实现该模型与环件冷轧三维有限元模型的结合。结果表明,该模型在预测动态复杂成形过程中的应力应变响应和织构演化方面都是可靠的;从轧制环件中很强的Goss织构{110}〈100〉看出,环件轧向的剪切变形是环件冷轧过程中的主要变形;环坯的织构和晶体结构对轧制环件中的织构类型的影响不大;在冷轧的后期环件织构演化迅速,这导致了这一时期环件的快速长大。

  7. NUMERICAL SIMULATION OF THE FIRST COLD ROLLING PASS OF A C-MN STRIP STEEL

    Directory of Open Access Journals (Sweden)

    Willian Costa do Nascimento

    2013-03-01

    Full Text Available This work presents the modeling by the finite element method of the first cold rolling pass of a four-high mill at the CSN steel plant. For this purpose, a two dimensional model is proposed considering the work-roll as a rigid surface together with the assumptions of plane-strain state for the strip and material isotropy with nonlinear isotropic workhardening. A C-Mn steel strip with initial thickness of 3.5 mm was first characterized by means of uniaxial tensile tests in specimens cut along the rolling direction to evaluate the work-hardening parameters. In the finite element model, the contact is defined by means of the Coulomb’s law to describe the friction between the work-roll and the strip surfaces. Moreover, the industrial back and forward tensions are also taken into account as prescribed conditions in the finite element model. The numerical predictions of the rolling load show a good agreement with the measured data and the forecasted value is determined with the slab-method.

  8. Data-based hybrid tension estimation and fault diagnosis of cold rolling continuous annealing processes.

    Science.gov (United States)

    Liu, Qiang; Chai, Tianyou; Wang, Hong; Qin, Si-Zhao Joe

    2011-12-01

    The continuous annealing process line (CAPL) of cold rolling is an important unit to improve the mechanical properties of steel strips in steel making. In continuous annealing processes, strip tension is an important factor, which indicates whether the line operates steadily. Abnormal tension profile distribution along the production line can lead to strip break and roll slippage. Therefore, it is essential to estimate the whole tension profile in order to prevent the occurrence of faults. However, in real annealing processes, only a limited number of strip tension sensors are installed along the machine direction. Since the effects of strip temperature, gas flow, bearing friction, strip inertia, and roll eccentricity can lead to nonlinear tension dynamics, it is difficult to apply the first-principles induced model to estimate the tension profile distribution. In this paper, a novel data-based hybrid tension estimation and fault diagnosis method is proposed to estimate the unmeasured tension between two neighboring rolls. The main model is established by an observer-based method using a limited number of measured tensions, speeds, and currents of each roll, where the tension error compensation model is designed by applying neural networks principal component regression. The corresponding tension fault diagnosis method is designed using the estimated tensions. Finally, the proposed tension estimation and fault diagnosis method was applied to a real CAPL in a steel-making company, demonstrating the effectiveness of the proposed method.

  9. Models and Algorithms of Production Scheduling in Tandem Cold Rolling%冷轧生产调度模型及算法

    Institute of Scientific and Technical Information of China (English)

    赵珺; 刘全利; 王伟

    2008-01-01

    The complexity of production scheduling problem in cold rolling line is analyzed, which is formulated as two parts, namely, the coil-merging optimization and the rolling batch planning. The optimization of steel coil merging is constructed as a multiple container packing problem (MCPP) that is computed by a new proposed algorithm, discrete differential evolution (DDE), in this paper. A specific double traveling salesman problem (DTSP) is modeled for the rolling batch planniug, and a hybrid heuristic method on the basis of evolutionary mechanism and local search is presented to solve this model. The experimental results with real production data from Shanghai Baostesl Co. Ltd. show that the production scheduling method suggested in this paper is effective.

  10. Magnesium-Nickel alloy for hydrogen storage produced by melt spinning followed by cold rolling

    Directory of Open Access Journals (Sweden)

    Daniel Rodrigo Leiva

    2012-10-01

    Full Text Available Severe plastic deformation routes (SPD have been shown to be attractive for short time preparation of magnesium alloys for hydrogen storage, generating refined microstructures and interesting hydrogen storage properties when compared to the same materials processed by high-energy ball milling (HEBM, but with the benefit of higher air resistance. In this study, we present results of a new processing route for Mg alloys for hydrogen storage: rapid solidification followed by cold work. A Mg97Ni3 alloy was processed by melt spinning (MS and by extensive cold rolling (CR. Submitting Mg97Ni3 ribbons between steel plates to cold rolling has shown to be a viable procedure, producing a thin cold welded foil, with little material waste. The as-processed material presents a high level of [002] fiber texture, a sub microcrystalline grain structure with a high density of defects, and also a fine dispersion of Mg2Ni nanoparticles. This refined microstructure allied to the developed texture resulted in enhanced activation and H-sorption kinetics properties.

  11. Textures and Properties of Hot Rolled High Strength Ti-IF Steels

    Institute of Scientific and Technical Information of China (English)

    GUO Yan-hui; WANG Zhao-dong; ZOU Wen-wen; LIU Xiang-hua; WANG Guo-dong

    2008-01-01

    The texture evolution in a high strength Ti-IF steel during the processing of hot rolling,cold rolling,and annealing is studied.For comparison,both ferrite rolling and austenite rolling are employed.It is found that the texture type is the.same after ferrite rolling and austenite rolling,but the texture intensity is much higher in the ferriterolled sample.Furthermore,texture characteristics at the surface are absolutely different from those at the mid-section in both ferrite rolled and austenite rolled samples,as well as under the cold rolled and annealed conditions.The shear texture {110} disappears and orientation rotates along {110} →{554}→{111}→{111}→{223} during cold rolling.Compared to the austenite rolled sample,the properties of the cold rolled and annealed sheet which is subjected to ferrite rolling are higher.

  12. Evolution of Oxide Inclusions in Si-Mn Killed Steels During Hot-Rolling Process

    Science.gov (United States)

    Yang, Wen; Guo, Changbo; Zhang, Lifeng; Ling, Haitao; Li, Chao

    2017-10-01

    The evolution of oxide inclusions in Si-Mn killed steels refined by slags of different basicity during a four-pass industrial hot-rolling process was investigated using an automated microscopy system. High-basicity refining slag induced the formation of CaO- and Al2O3-containing inclusions, while refining slag with 0.8 basicity induced dominant inclusions of SiO2 and MnO-SiO2. CaO-SiO2-Al2O3 inclusions mainly formed endogenously during solidification and cooling of Ca-containing steels, where Ca originated from slag-steel reactions. However, the larger-sized higher-CaO inclusions originated from slag entrainment. Different inclusions presented different hot-rolling behaviors. The inclusion composition changed by deformation and new phase formation. The dominant oxide types were unchanged under refinement by low-basicity slag; however, they changed under refinement with high-basicity slag. The deformation index of inclusions decreased with increasing accumulated reduction (AR) of the steel. The difference in deformation index between different inclusion types was the largest in the first rolling stage and decreased in subsequent stages. SiO2-CaO and SiO2-MnO-CaO inclusions had larger deformation indices during hot rolling but smaller indices in the last two stages. High-basicity slag increased inclusion complexity; from the perspective of cold-drawing performance, low-basicity refining slag is better for the industrial production of tire-cord steels.

  13. Research and Development Trend of Shape Control for Cold Rolling Strip

    Science.gov (United States)

    Wang, Dong-Cheng; Liu, Hong-Min; Liu, Jun

    2017-07-01

    Shape is an important quality index of cold rolling strip. Up to now, many problems in the shape control domain have not been solved satisfactorily, and a review on the research progress in the shape control domain can help to seek new breakthrough directions. In the past 10 years, researches and applications of shape control models, shape control means, shape detection technology, and shape control system have achieved significant progress. In the aspect of shape control models, the researches in the past improve the accuracy, speed and robustness of the models. The intelligentization of shape control models should be strengthened in the future. In the aspect of the shape control means, the researches in the past focus on the roll optimization, mill type selection, process optimization, local strip shape control, edge drop control, and so on. In the future, more attention should be paid to the coordination control of both strip shape and other quality indexes, and the refinement of control objective should be strengthened. In the aspects of shape detection technology and shape control system, some new types of shape detection meters and shape control systems are developed and have successfully industrial applications. In the future, the standardization of shape detection technology and shape control system should be promoted to solve the problem of compatibility. In general, the four expected development trends of shape control for cold rolling strip in the future are intelligentization, coordination, refinement, and standardization. The proposed research provides new breakthrough directions for improving shape quality.

  14. Research and Development Trend of Shape Control for Cold Rolling Strip

    Science.gov (United States)

    Wang, Dong-Cheng; Liu, Hong-Min; Liu, Jun

    2017-09-01

    Shape is an important quality index of cold rolling strip. Up to now, many problems in the shape control domain have not been solved satisfactorily, and a review on the research progress in the shape control domain can help to seek new breakthrough directions. In the past 10 years, researches and applications of shape control models, shape control means, shape detection technology, and shape control system have achieved significant progress. In the aspect of shape control models, the researches in the past improve the accuracy, speed and robustness of the models. The intelligentization of shape control models should be strengthened in the future. In the aspect of the shape control means, the researches in the past focus on the roll optimization, mill type selection, process optimization, local strip shape control, edge drop control, and so on. In the future, more attention should be paid to the coordination control of both strip shape and other quality indexes, and the refinement of control objective should be strengthened. In the aspects of shape detection technology and shape control system, some new types of shape detection meters and shape control systems are developed and have successfully industrial applications. In the future, the standardization of shape detection technology and shape control system should be promoted to solve the problem of compatibility. In general, the four expected development trends of shape control for cold rolling strip in the future are intelligentization, coordination, refinement, and standardization. The proposed research provides new breakthrough directions for improving shape quality.

  15. Evolution of microstructure and textures in cold rolled Fe-6.5 % Si alloy thin sheet during annealing%退火过程中Fe-6.5%Si冷轧薄板组织及织构的演变

    Institute of Scientific and Technical Information of China (English)

    王文强; 毛卫民; 杨平; 叶丰

    2013-01-01

    观察分析了Fe-6.5% Si合金冷轧前后及在不同再结晶退火过程中的组织、织构及有序结构的特点及其演变规律,用以分析织构形成机制及其影响因素.结果表明,间隙溶质原子偏聚于{110}面的概率大于{112}面,明显提高位错在{110}面滑移的临界分切应力;代位溶质原子有可能同步提高{110}和{112}面的临界分切应力,降低这两面的临界分切应力差;因此溶质原子都会导致{112}面更活跃的滑移和更强的{100} 冷轧织构.退火过程中{111} 取向晶粒易于长入{001}和{112} 取向形变晶粒,使{111} 再结晶织构增强.冷变形会降低合金的有序化程度;DO3有序化过程的二级相变特点使之在退火加热过程中先于再结晶出现,再结晶之前的回复会促进有序化过程.%Characteristics and evolution of microstructure, texture and ordered structure in Fe-6. 5% Si alloy were observed and analyzed before and after cold rolling as well as during different recrystallization annealing, in order to reveal the mechanism of texture formation and the influencing factors. The results show that the probability of interstitial solute atoms lying in { 110} planes is higher than that lying in { 112} planes, which increases the critical resolved shear stress (CRSS) on { 110} plane significantly. Substitutional solute atoms may increase CRSS on {110} and {112} plane simultaneously, which decreases the difference of CRSS between { 110} and { 112} plane. Therefore, the solute atoms would induce more active slips of the dislocations on { 112} planes and stronger {100} texture after cold rolling, {111} oriented grains grow at the expense of the { 100 } and { 112} grains easily during annealing, which leads to stronger {111} recrystallization texture. The ordering degree is decreased after cold deformation. The ordering process of D03 with the characteristic of second order phase transition appears before recrystallization canduring annealing

  16. MATHEMATICAL MODELS FOR MICROSTRUCTURE EVOLUTION IN THE SEAMLESS TUBE ROLLING

    Directory of Open Access Journals (Sweden)

    Ricardo Nolasco de Carvalho

    2013-10-01

    Full Text Available The goal of this work is to present recent developments on mathematical modeling for microstructure evolution in different steel types, applied to a continuous rolling of seamless tubes. The development of these models depends on careful characterization of the thermomechanical cycle and/on correct selection and adjustment of equations which describes the several metallurgical phenomena involved on this process. The adjustments of these models are done using the results obtained in hot torsion simulations. For this, the thermomechanical cycles are simplified considering the equipment limitations in reproduce some strain, strain rates and cooling rates developed industrially. Samples for optical microscopy were obtained by interruption of simulations after selected steps of process. After adjustment of each model with results from simulation, the final microstructures are compared with those obtained in industrial scale. In general, good correlations are observed.

  17. Recrystallization kinetics of individual bulk grains in 90% cold-rolled aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Lauridsen, E.M.; Poulsen, H.F.; Nielsen, S.F.; Juul Jensen, D

    2003-09-03

    The recrystallization kinetics of a 90% cold-rolled commercial aluminium alloy AA1050 annealed at 270 deg. C has been investigated by use of 3-dimensional X-ray diffraction (3DXRD) microscopy. For the first time growth curves of a large number of individual bulk grains have been measured in situ during recrystallization providing unique information on the nucleation and growth behaviour of the individual grains. From observations of 244 individual growth curves, it is found that each grain has its own growth kinetics. The orientation dependencies of the recrystallization kinetics are investigated by grouping the measured growth curves into cube, rolling and other orientation classes. Based on analysis of the growth curves, distributions of nucleation time, grain size and growth rate has been derived, and are used for a discussion of the recrystallization kinetics of aluminium AA1050.

  18. The Role of Surface Preparation Parameters on Cold Roll Bonding of Aluminum Strips

    Science.gov (United States)

    Jamaati, Roohollah; Toroghinejad, Mohammad Reza

    2011-03-01

    It is the objective of this article to investigate the influence of surface preparation on the cold roll bonding (CRB) process. In this context, the effects of surface preparation parameters consisting of surface preparation method, surface roughness, scratch-brushing parameters, and the delay time between surface preparation and rolling are investigated on the bond strength of aluminum strips. The bond strength of two adjacent aluminum strips produced by the CRB process is evaluated by the peeling test. Furthermore, the interface region is investigated by metallographic observations. Our findings indicate that higher surface roughness values and shorter delay times improve the bond strength. It is also found that degreasing followed by scratch-brushing yield the best bonding properties.

  19. In Situ XRD Studies of the Process Dynamics During Annealing in Cold-Rolled Copper

    Science.gov (United States)

    Dey, Santu; Gayathri, N.; Bhattacharya, M.; Mukherjee, P.

    2016-09-01

    The dynamics of the release of stored energy during annealing along two different crystallographic planes, i.e., {111} and {220}, in deformed copper have been investigated using in situ X-ray diffraction measurements at 458 K and 473 K (185 °C and 200 °C). The study has been carried out on 50 and 80 pct cold-rolled Cu sheets. The microstructures of the rolled samples have been characterized using optical microscopy and electron backscattered diffraction measurements. The microstructural parameters were evaluated from the X-ray diffractogram using the Scherrer equation and the modified Rietveld method. The stored energy along different planes was determined using the modified Stibitz formula from the X-ray peak broadening, and the bulk stored energy was evaluated using differential scanning calorimetry. The process dynamics of recovery and recrystallization as observed through the release of stored energy have been modeled as the second-order and first-order processes, respectively.

  20. Modelling the Process Chain of Cold Rolled Dual Phase Steel for Automotive Application

    Science.gov (United States)

    Ramazani, A.; Prahl, U.

    This project aims to develop a virtual process chain for the production of components out of cold-rolled dual-phase (DP) steel. The simulation chain starts with cold-rolled strip. During intercritical annealing process all relevant steps like recrystallization, austenite formation and grain growth, ferrite and martensite transformation including bainite fractions and quasi-tempering during hot dip coating and coiling are taken into account. Concerning the final mechanical properties transformation induced micro eigenstresses are described as well as strain partitioning on microscale during cold forming. This multi-scale and process-spanning approach enables the local properties in the part for varying composition and processing conditions. Thus, it can be used for the knowledge driven design and optimization of tailored material and process. To describe all the steps along the process chain, various simulation programs have been linked. By comparison of simulation and experimental results the predictability of this approach can be shown an in a later stage the integrative simulation approach will be further developed towards application for material and process design.

  1. Recovery and recrystallization in commercial purity aluminum cold rolled to an ultrahigh strain

    DEFF Research Database (Denmark)

    Mishin, Oleg; Godfrey, A.; Juul Jensen, Dorte;

    2013-01-01

    Recovery and recrystallization were studied in commercial purity aluminum cold rolled to an ultrahigh strain (εvM=6.4) and isothermally annealed at 300°C. The deformed material consists of three layers with similar fractions of high-angle boundaries (HABs) and similar lamellar boundary spacings......, pronounced recrystallization in the subsurface layers is delayed, and the recrystallized grain size is larger than in the center. It is concluded that the changes taking place during recovery are very significant in determining the subsequent recrystallization behavior in terms of the final grain size...

  2. Simulation of damage evolution during hot ring rolling

    NARCIS (Netherlands)

    Wang, Chao

    2016-01-01

    Ring rolling provides a cost-effective process route for manufacturing seamless rings. The bearing rings, i.e. the inner race and the outer race of a rolling bearing, are typically manufactured by the hot ring rolling process. Bearing steels have a relatively high alloy content for improved hardenab

  3. The Influence of Initial Microstructure on the Recrystallization Behaviour of Cold-Rolled AA3003

    Science.gov (United States)

    Babaghorbani, Payman; Poole, Warren J.; Wells, Mary A.; Parson, Nick C.

    Due to an excellent combination of strength, formability, corrosion resistance and material cost, extruded Al-Mn alloys (e.g. AA3003) are widely used in heat exchanger applications for automotive and off road applications. Grain size control is essential, as it affects important properties such as corrosion resistance, strength and formability. The present work describes experimental observations on the microstructure resulting from different homogenization practices of AA3003 which modify the dispersoid distribution and the initial grain size. This work considers deformation by cold rolling to reductions of 10-80 pet followed by annealing at the temperature range of 350 to 600 °C. Preliminary results show that there is a critical temperature below which concurrent precipitation of Mn-bearing dispersoids retards recovery and static recrystallization giving rise to different recrystallized grain sizes. The effect of initial grain size was observed to be significant when there were almost no dispersoids with cold reductions of 10-20 pct.

  4. Evolution of sub-horizon cold dark matter perturbations

    CERN Document Server

    Boehmer, Christian G

    2010-01-01

    We investigate the evolution of sub-horizon cold dark matter perturbation in the dark energy dominated era of the Universe. By generalising the Meszaros equation to be valid for an arbitrary equation of state parameter, we derive the $w$-Meszaros equation. Its solutions determine the evolution of the cold dark matter perturbation by neglecting dark energy perturbations. Our analytical results provide a qualitative understanding of this evolution.

  5. Mechanical properties and texture evolution during hot rolling ofAZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    SUN Hong-fei; LIANG Shu-jin; WANG Er-de

    2009-01-01

    Mechanical properties and texture evolutions of the as-rolled AZ31 Mg sheets were investigated. The results show that the grains of the sheets are significantly refined after hot rolling. The mechanical properties of the as-rolled samples are enhanced due to the grain size refinement. The intensity of basal texture decreases with the increase of deformation ratio, and double-peak type basal texture is discovered in the intermediate and large strain hot rolling processes. The formation of the texture is ascribed to the activities of prismatic and non-basal slips, which is the same as the 30% rolled and 50% rolled samples. The incline of basal planes exerts an effect on the mechanical anisotropy during tension along rolling direction (RD) and transverse direction (TD) at room temperature.

  6. Investigation on Friction and Wear of Cold Rolled High Strength Steel against an AISI52100 Counterpart

    Directory of Open Access Journals (Sweden)

    Jiwon Hur

    2017-03-01

    Full Text Available This article investigates the friction and wear of cold rolled high strength steel at various displacement amplitudes. Reciprocal sliding tests are carried out using a ball-on-flat testing apparatus. The tangential force occurring at the contact surface between a high strength steel specimen and an AISI52100 ball is measured during the tests. After each test, the worn surface profile on the steel specimen is determined. Experimental results show that the ratio of the maximum tangential to the normal force remains at 0.7 after an initial rapid increase, and the ratio does not greatly change according to the imposed displacement amplitudes (in the range of 0.05 mm and 0.3 mm. The wear volume loss on the steel specimen increases according to the number of cycles. It is determined that the wear rate of the specimen changes with respect to the imposed displacement amplitude. That is, the wear rate rapidly increases within the displacement amplitude range of 0.05 mm to 0.09 mm, while the wear rate gradually increases when the displacement amplitude is greater than 0.2 mm. The obtained results provide the friction and wear behaviors of cold rolled high strength steel in fretting and reciprocal sliding regimes.

  7. Composite Aluminum-Copper Sheet Material by Friction Stir Welding and Cold Rolling

    Science.gov (United States)

    Kahl, S.; Osikowicz, W.

    2013-08-01

    An aluminum alloy and a pure copper material were butt-joined by friction stir welding and subsequently cold rolled. The cold-rolling operation proved to be very advantageous because small voids present after friction stir welding were closed, the interface area per material thickness was enlarged, a thin intermetallic layer was partitioned, and the joint was strengthened by strain hardening. Tensile test specimens fractured in the heat-affected zone in the aluminum material; tensile strengths of the joints exceeded the tensile strengths of the base materials and were as high as 335 MPa. During soft annealing of the composite material, a 6-8-μm-thick intermetallic layer was grown at the interface. Nevertheless, tensile fracture still occurred in the heat-affected zone of the aluminum material. Electrical resistivity of the joint was smaller than resistivity of the aluminum material. Production of such composite material would result in coiled sheet material that could be subjected to further treatments such as electroplating and forming operations in an efficient and economically viable manner. The new composite material is promising for emerging automotive and industrial electrical applications.

  8. Multi objective Taguchi optimization approach for resistance spot welding of cold rolled TWIP steel sheets

    Science.gov (United States)

    Tutar, Mumin; Aydin, Hakan; Bayram, Ali

    2017-08-01

    Formability and energy absorption capability of a steel sheet are highly desirable properties in manufacturing components for automotive applications. TWinning Induced Plastisity (TWIP) steels are, new generation high Mn alloyed steels, attractive for the automotive industry due to its outstanding elongation (%40-45) and tensile strength (~1000MPa). So, TWIP steels provide excellent formability and energy absorption capability. Another required property from the steel sheets is suitability for manufacturing methods such as welding. The use of the steel sheets in the automotive applications inevitably involves welding. Considering that there are 3000-5000 welded spots on a vehicle, it can be interpreted that one of the most important manufacturing method is Resistance Spot Welding (RSW) for the automotive industry. In this study; firstly, TWIP steel sheet were cold rolled to 15% reduction in thickness. Then, the cold rolled TWIP steel sheets were welded with RSW method. The welding parameters (welding current, welding time and electrode force) were optimized for maximizing the peak tensile shear load and minimizing the indentation of the joints using a Taguchi L9 orthogonal array. The effect of welding parameters was also evaluated by examining the signal-to-noise ratio and analysis of variance (ANOVA) results.

  9. Chemical banding revealed by chemical etching in a cold-rolled metastable stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Celada, C., E-mail: c.celada@cenim.csic.es [MATERALIA Research Group, Department of Physical Metallurgy, Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Av. Gregorio del Amo 8, 28040 Madrid (Spain); Toda-Caraballo, I., E-mail: it247@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Kim, B., E-mail: bnk20@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); San Martín, D., E-mail: dsm@cenim.csic.es [MATERALIA Research Group, Department of Physical Metallurgy, Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Av. Gregorio del Amo 8, 28040 Madrid (Spain)

    2013-10-15

    The current work describes the metallographic characterization of the initial microstructure of a cold rolled precipitation hardening semi-austenitic stainless steel (12Cr–9Ni–4Mo–2Cu–1Ti, in wt.%). The use of the Lichtenegger and Blöch (L–B) color etching solution has been shown to reveal not only the phases present in the microstructure, but also the existence of chemical banding along the rolling direction. The L–B reagent has been found to color the microstructure in bands depending on what alloying elements have segregated to each band. Two-dimensional electron probe microanalysis (EPMA) maps have shown that Ni, Cu and Ti segregate together in the bands, while Cr has an opposite behavior. Mo has a mixed segregation behavior although much weaker than the other elements and more prompt to segregate like Ni does. A direct comparison of light optical micrographs with the EPMA maps of the same area of the microstructure has enable to establish a direct relationship between the alloying element band concentration and the resulting etching color contrast obtained with the L–B reagent. Thermodynamic calculations predict that solidification in this steel takes place with ferrite as the primary phase. Equilibrium partitioning coefficient calculations seem to support the observed segregation patterns. - Highlights: • A cold rolled metastable stainless steel has been characterized thoroughly. • EPMA shows that Ni, Cu and Ti segregate together; Cr in an opposite way. • L–B color etching is sensitive to the segregation of these chemical elements. • This chemical banding has been reduced by applying a homogenization heat treatment. • Partitioning coefficient calculations agree with the observed segregation patterns.

  10. Effects of Rolling Reduction and Strength of Composed Layers on Bond Strength of Pure Copper and Aluminium Alloy Clad Sheets Fabricated by Cold Roll Bonding

    OpenAIRE

    Yoji Miyajima; Kotaro Iguchi; Susumu Onaka; Masaharu Kato

    2014-01-01

    Three types of clad sheets, Cu/Al, Cu/AA5052, and Cu/AA5083, were produced by cold roll bonding with the rolling reduction of 50% and 75%. Tensile shear tests which give tensile shear strength were performed in order to assess the bond strength. Scanning electron microscopy was performed on the fractured interface produced by the tensile shear tests, which suggests that the fracture occurs within the Al alloy layer. The tensile shear strengths considering the area fraction of deposit of Al al...

  11. Effects of Rolling Reduction and Strength of Composed Layers on Bond Strength of Pure Copper and Aluminium Alloy Clad Sheets Fabricated by Cold Roll Bonding

    Directory of Open Access Journals (Sweden)

    Yoji Miyajima

    2014-01-01

    Full Text Available Three types of clad sheets, Cu/Al, Cu/AA5052, and Cu/AA5083, were produced by cold roll bonding with the rolling reduction of 50% and 75%. Tensile shear tests which give tensile shear strength were performed in order to assess the bond strength. Scanning electron microscopy was performed on the fractured interface produced by the tensile shear tests, which suggests that the fracture occurs within the Al alloy layer. The tensile shear strengths considering the area fraction of deposit of Al alloy on Cu side were compared with the shear stress converting from the ultimate tensile strengths. As a result, the tensile shear strength of the clad sheets is attributed to the shear strength of Al alloy layer close to the well bonded interface. A simple model was proposed that explains the effects of the rolling reduction and area fraction of deposit of Al alloy.

  12. Effect of microstructure on the fatigue of hot-rolled and cold-drawn NiTi shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gall, Ken [Department of Materials Science and Engineering, Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)], E-mail: ken.gall@mse.gatech.edu; Tyber, Jeff; Wilkesanders, Geneva [Department of Materials Science and Engineering, Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Robertson, Scott W.; Ritchie, Robert O. [Department of Materials Science and Engineering, University of California, Berkeley, CA 94720 (United States); Maier, Hans J. [Lehrstuhl fuer Werkstoffkunde (Materials Science), University of Paderborn, 33095 Paderborn (Germany)

    2008-07-15

    We present results from a systematic study linking material microstructure to monotonic and fatigue properties of NiTi shape memory alloys. We consider Ni-rich materials that are either (1) hot rolled or (2) hot rolled and cold drawn. In addition to the two material processing routes, heat treatments are used to systematically alter material microstructure giving rise to a broad range of thermal, monotonic and cyclic properties. The strength and hardness of the austenite and martensite phases initially increase with mild heat treatment (300 deg. C), and subsequently decrease with increased aging temperature above 300 deg. C. This trend is consistent with transmission electron microscopy observed precipitation hardening in the hot-rolled material and precipitation hardening plus recovery and recrystallization in the cold-drawn materials. The low-cycle pseudoelastic fatigue properties of the NiTi materials generally improve with increasing material strength, although comparison across the two product forms demonstrates that higher measured flow strength does not assure superior resistance to pseudoelastic cyclic degradation. Fatigue crack growth rates in the hot-rolled material are relatively independent of heat treatment and demonstrate similar fatigue crack growth rates to other NiTi product forms; however, the cold-drawn material demonstrates fatigue threshold values some 5 times smaller than the hot-rolled material. The difference in the fatigue performance of hot-rolled and cold-drawn NiTi bars is attributed to significant residual stresses in the cold-drawn material, which amplify fatigue susceptibility despite superior measured monotonic properties.

  13. Effect of annealing cooling rate on microstructure and mechanical property of 100Cr6 steel ring manufactured by cold ring rolling process

    Institute of Scientific and Technical Information of China (English)

    魏文婷; 吴敏

    2014-01-01

    Pre-heat treatment is a vital step before cold ring rolling and it has significant effect on the microstructure and mechanical properties of rolled rings. The 100Cr6 steel rings were subjected to pre-heat treatment and subsequent cold rolling process. Scanning electron microscopy and tensile tests were applied to investigate microstructure characteristic and mechanical property variations of 100Cr6 steel rings undergoing different pre-heat treatings. The results indicate that the average diameter of carbide particles, the tensile strength and hardness increase, while the elongation decreases with the decrease of cooling rate. The cooling rate has minor effect on the yield strength of sample. After cold ring rolling, the ferrite matrix shows a clear direction along the rolling direction. The distribution of cementite is more homogeneous and the cementite particles are finer. Meanwhile, the hardness of the rolled ring is higher than that before rolling.

  14. Evolution of microstructure and texture during recovery and recrystallization in heavily rolled aluminum

    DEFF Research Database (Denmark)

    Mishin, Oleg; Godfrey, A.; Yu, Tianbo

    2015-01-01

    The annealing behavior of nanostructured aluminum AA1050 prepared by cold rolling to an ultrahigh strain (εvM = 6.4) has been investigated using both transmission electron microscopy and electron backscatter diffraction techniques, paying particular attention to changes in microstructure and text......The annealing behavior of nanostructured aluminum AA1050 prepared by cold rolling to an ultrahigh strain (εvM = 6.4) has been investigated using both transmission electron microscopy and electron backscatter diffraction techniques, paying particular attention to changes in microstructure...

  15. TEXTURE AND CRYSTALLINITY EVOLUTION IN ISOTACTIC POLYPROPYLENE INDUCED BY ROLLING AND THEIR INFLUENCE ON MECHANICAL PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    Juan Jia; Dierk Raabe; Wei-min Mao

    2006-01-01

    The orientation and crystallinity evolution of isotactic polypropylene (iPP) induced by rolling were studied using wide angle X-ray scattering with an area detector. The tensile mechanical properties of rolled isotactic polypropylene sheets were also measured in this work. The texture component method was used to analyze the rolling texture. The rolling texture consists mainly of (010)[001], (130)[001] and [001]//RD fiber components in the sample with a rolling true strain of 1.5.The results reveal that crystallinity drastically decreases during rolling. It is suggested that amorphization is a deformation mechanism which takes place as an alternative to crystallographic intralamellar slip depending on the orientation of the lamellae. Both the orientation and crystallinity affect the tensile mechanical properties of rolled polypropylene. Crystallinity influences the elastic modulus on both directions and yield strength on transverse direction at the first stage of deformation.Orientation is the main reason for the changes of mechanical properties, especially at the latter part of deformation. The changes of both tensile strength and elongation percentage on rolling direction are larger than those on transverse direction,which results from the orientation. At last, the anisotropic mechanical properties occur on the rolling and transverse direction: high tensile strength with low elongation percentage on rolling direction and low tensile strength with high elongation percentage on transverse direction.

  16. Jet Evolution in Hot and Cold QCD Matter

    OpenAIRE

    Domdey, Svend Oliver

    2010-01-01

    In this thesis, we study the evolution of energetic partons in hot and cold QCD matter. In both cases, interactions with the medium lead to energy loss of the parton and its transverse momentum broadens. The propagation of partons in cold nuclear matter can be investigated experimentally in deep-inelastic scattering (DIS) on nuclei. We use the dipole model to calculate transverse momentum broadening in DIS on nuclei and compare to experimental data from HERMES. In hot matter, the evolution of...

  17. Properties and Microstructure of One-Step Cold Rolled Steel Strip for Shadow Mask

    Institute of Scientific and Technical Information of China (English)

    LIANG Xuan; LI Jun; PENG Ying-hong

    2008-01-01

    The effect of recrystallization annealing temperature on the properties and microstructure of one-step cold rolled steel strip for shadow mask was studied.The results showed that there was no yield point elongation when the tensile tests were performed on the samples for annealing temperatures ranging from 750℃ to 810 ℃.Moreover,increasing annealing temperature resulted in large grains,which was beneficial to the formability and magnetic property of steel strips.On the other hand,when the sample was annealed at 840 ℃,its microstructure showed ununifortuity with 0.04% yield point elongation,which was not good for the function of the shadow mask.Therefore,the proper recrystallization annealing temperature was about 810 ℃ for the present steel strip for shadow mask.

  18. Enhanced mechanical stability of ultrafine grained steel through intercritical annealing cold rolled martensite

    Institute of Scientific and Technical Information of China (English)

    Huifang LAN; Xianghua LIU; Linxiu DU

    2012-01-01

    The ultrafine grained ferritic steels possess high strength but low ductility due to the shortage of work hardening.Fine grained ferrite-martensite dual phase microstructure was obtained in a microalloyed steel and low carbon steels through intercritical annealing of the cold rolled martensite.The dual phase microstructure was uniform and the ferrite grain size was smaller in the microalloyed steel resulted from the pinning effect of microalloyed precipitates.But ferrite grown apparently and the volume fraction of the martensite was much higher without the addition of microalloying elements.By introducing martensite into the fine grained ferrite,the work hardening was effectively improved,leading to better mechanical stability.As a result of the fine ferrite grain size as well as uniform distribution of the martensite,the work hardening was enhanced,showing better strength-ductility balance in the microalloyed dual phase steel.

  19. Change in magnetic properties of a cold rolled and thermally aged Fe-Cu alloy

    Science.gov (United States)

    Park, D. G.; Ryu, K. S.; Kobayashi, S.; Takahashi, S.; Cheong, Y. M.

    2010-05-01

    The variation in magnetic properties of a Fe-1%Cu model alloy due to a cold rolling and a thermal aging has been evaluated to simulate the radiation damage of reactor pressure vessel of nuclear power plant. The thermal aging was conducted at 500 °C with different aging times in series. The hysteresis loops, magnetic Barkhausen noise (BN) and Vickers microhardness were measured for prestrained, strained, and thermal aged samples. The coercivity increased by a plastic strain and decreased by thermal aging, The BN decreased in the prestrained and strained samples but large changes were observed in the strained sample. These results were interpreted in terms of the domain wall motion signified by a change in the mean free path associated with microinternal stress and copper rich precipitates.

  20. Annealing Behavior at Triple Junctions in High-Purity Aluminum After Slight Cold Rolling

    Science.gov (United States)

    Yin, Wenhong; Wang, Weiguo; Fang, Xiaoying; Qin, Congxiang

    2017-04-01

    High-purity polycrystalline aluminum samples with a typical grain size of approximately 30 μm were slightly cold-rolled with a thickness reduction of 15%, and then, off-line in situ electron backscatter diffraction was used to identify the annealing behavior at triple junctions during annealing at 400 °C. The results show that recrystallization nuclei are developed at some triple junctions during annealing. High-angle grain boundaries migrate from harder grains to softer grains at the triple junctions leading to the formation of nuclei. All such nuclei show Σ3 orientation relationships with the parent grains, and the bounded Σ3 boundaries are found to be incoherent. During further annealing, these nuclei are consumed by other growing grains, indicating that their presence is just a release of the strain concentration at the triple junctions.

  1. Linking recovery and recrystallization through triple junction motion in aluminum cold rolled to a large strain

    DEFF Research Database (Denmark)

    Yu, Tianbo; Hansen, Niels; Huang, Xiaoxu

    2013-01-01

    transition into a more equiaxed structure, where recrystallization nuclei start to evolve. The apparent activation energy for the microstructural coarsening is estimated separately for different stages characterized by an increase in the lamellar boundary spacing measured by EBSD and ECC. The apparent...... activation energy increases during annealing, from 110kJmol−1 at the beginning to 230–240kJmol−1 at the end of uniform coarsening, linking the recovery stages to recrystallization. The increase in activation energy underpins operation of different diffusion mechanisms for migration of boundaries...... and their junctions during coarsening, and solute drag may become increasingly important as the structure coarsens. These findings form the basis for a discussion of the thermal behavior of a fine lamellar structure produced by cold rolling to a large strain of both scientific and applied interest....

  2. New technology for recycling materials from oily cold rolling mill sludge

    Institute of Scientific and Technical Information of China (English)

    Bo Liu; Shen-gen Zhang; Jian-jun Tian; De-an Pan; Ling Meng; Yang Liu

    2013-01-01

    Oily cold rolling mill (CRM) sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new process of“hydrometallurgical treatment+hydrothermal synthesis”was investigated for the combined recovery of iron and organic materials from oily CRM sludge. Hydrometallurgical treatment, mainly including acid leaching, centrifugal separation, neutralization reaction, oxidizing, and preparation of hydrothermal reaction precursor, was first utilized for processing the sludge. Then, micaceous iron oxide (MIO) pigment powders were prepared through hydrothermal reaction of the obtained precursor in alkaline media. The separated organic materials can be used for fuel or chemical feedstock. The quality of the prepared MIO pigments is in accordance with the standards of MIO pigments for paints (ISO 10601-2007). This clean, eff ective, and economical technology off ers a new way to recycle oily CRM sludge.

  3. Draw-Bending Analysis of a Cold Rolled DP980 Steel Sheet

    Science.gov (United States)

    Verma, Rahul K.; Noma, Nobuyasu; Chung, Kwansoo; Kuwabara, Toshihiko

    2011-05-01

    To assess the springback prediction accuracy of the recently proposed model (Verma et. al., 2011), simulations for tension-compression (TC) and draw-bending of a cold rolled DP980 steel sheet (Noma and Kuwabara, 2010b) were performed. Using a rotating die and a specimen specially designed to introduce the uniaxial state of stress during the draw bending test, friction could be neglected and the shape of the yield surface did not play any role in accurate simulations. The effects of incorporating permanent softening and the plastic strain dependent Young's modulus were studied in detail and it was found that the incorporation of permanent softening and the plastic strain dependent Young's modulus both was important for accurate springback prediction.

  4. Annealing Behavior at Triple Junctions in High-Purity Aluminum After Slight Cold Rolling

    Science.gov (United States)

    Yin, Wenhong; Wang, Weiguo; Fang, Xiaoying; Qin, Congxiang

    2017-02-01

    High-purity polycrystalline aluminum samples with a typical grain size of approximately 30 μm were slightly cold-rolled with a thickness reduction of 15%, and then, off-line in situ electron backscatter diffraction was used to identify the annealing behavior at triple junctions during annealing at 400 °C. The results show that recrystallization nuclei are developed at some triple junctions during annealing. High-angle grain boundaries migrate from harder grains to softer grains at the triple junctions leading to the formation of nuclei. All such nuclei show Σ3 orientation relationships with the parent grains, and the bounded Σ3 boundaries are found to be incoherent. During further annealing, these nuclei are consumed by other growing grains, indicating that their presence is just a release of the strain concentration at the triple junctions.

  5. Mixing behaviors in Cu/Ni and Ni/V multilayers induced by cold rolling

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z. [Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, WI 53706 (United States); Perepezko, J.H., E-mail: perepezk@engr.wisc.edu [Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, WI 53706 (United States); Larson, D.; Reinhard, D. [CAMECA Instruments Inc., 5500 Nobel Drive, Madison, WI 53711 (United States)

    2015-09-15

    Highlights: • The composition profiles of Cu/Ni and Ni/V multilayers were investigated. • A compositional oscillation was observed in the Cu/Ni composition profile. • The Ni/V composition profile varies smoothly and continuously between end members. • The effective diffusion coefficients were enhanced by about 30 order of magnitudes. • The effective temperature were estimated as 946 K for Cu/Ni and 936 K for Ni/V. - Abstract: Multilayers of Cu60/Ni40 and Ni70/V30 foil arrays were cold rolled in order to study the transformation reactions and mixing behaviors induced by deformation. Upon cold rolling, the layer thicknesses were refined to about 20 nm and solid solution phases were induced from pure end members (i.e. Cu, Ni and V) in both cases. The composition profiles for Cu/Ni and Ni/V multilayer samples at the deformation level where the solid solution phases coexist with end members were investigated by means of atom probe tomography and electron energy loss spectrum, respectively. An oscillation in the composition of Cu–Ni solid solution phase was observed, however the composition profile of Ni/V shows a smoothly varying curve between the end members. The effective diffusion coefficients were promoted by about 30 orders of magnitude for both Cu/Ni and Ni/V compared to room temperature diffusion. The effective temperature for Cu/Ni multilayers after 36 passes and Ni/V after 60 passes are estimated as 946 K and 936 K respectively.

  6. Inhibition of cold rolled steel corrosion by Tween-20 in sulfuric acid: weight loss, electrochemical and AFM approaches.

    Science.gov (United States)

    Mu, Guannan; Li, Xianghong

    2005-09-01

    The inhibiting action of a nonionic surfactant of Tween-20 on the corrosion of cold rolled steel (CRS) in 0.5-7.0 M sulfuric acid (H(2)SO(4)) was studied by weight loss and potentiodynamic polarization methods. Atomic force microscope (AFM) provided the surface conditions. The results show that inhibition efficiency increases with the inhibitor concentration, while it decreases with the sulfuric acid concentration. The adsorption of inhibitor on the cold rolled steel surface obeys the Langmuir adsorption isotherm equation. Effect of immersion time was studied and discussed. The effect of temperature on the corrosion behavior of cold rolled steel was also studied at four temperatures ranging from 30 to 60 degrees C, the thermodynamic parameters such as adsorption heat, adsorption free energy, and adsorption entropy were calculated. The results revealed that the adsorption was physisorption mechanism. A kinetic study of cold rolled steel in uninhibited and inhibited acid was also discussed. The kinetic parameters such as apparent activation energy, pre-exponential factor, rate constant, and reaction constant were calculated for the reactions of corrosion. The inhibition effect is satisfactorily explained by both thermodynamic and kinetic models. Polarization curves show that Tween-20 is a cathodic-type inhibitor in sulfuric acid. The results obtained from weight loss and potentiodynamic polarization are in good agreement, and the Tween-20 inhibition action could also be evidenced by surface AFM images.

  7. Effect of Cold Rolling on the Hydrogen Desorption Behavior of Binary Metal Hydride Powders under Microwave Irradiation

    Directory of Open Access Journals (Sweden)

    Ivaldete da Silva Dupim

    2015-10-01

    Full Text Available In this paper we report that cold rolling could drastically improve hydrogen desorption kinetics under microwave irradiation. Samples of metal hydride powders (TiH2, ZrH2, and MgH2 in as-received conditions and after cold rolling were microwave irradiated in a vacuum using a simple experimental setup. After irradiation, the samples were characterized by X-ray diffraction in other to evaluate the effectiveness of microwave heating. The diffraction patterns indicated that only MgH2 could be fully decomposed (dehydrided in the as received state. TiH2 was only partially decomposed while no decomposition was observed for ZrH2. However, cold rolling the hydride powders prior to microwave heating led to a significant improvement of hydride decomposition, resulting in the complete dehydriding of TiH2 and extensive dehydriding of ZrH2. These results clearly indicated the positive effects of cold rolling on the microwave assisted desorption of the investigated binary hydrides.

  8. Application of Smith Predictor Based on Single Neural Network in Cold Rolling Shape Control

    Institute of Scientific and Technical Information of China (English)

    WANG Yiqun; SUN Fu; LIU Jian; SUN Menghui; XIE Yihan

    2009-01-01

    Flatness is one of the most important criterion factors to evaluate the quality of the steel strip. To improve the strip' s flatness quality, the most frequently used methodology is to employ the closed-loop automatic shape control system. However, in the shape control system, the shape-meter is always installed at the down way of the exit of the cold rolling mill and can not sense the changes of the strip flatness in the rolling gap directly. This kind of installation results in the delay of the feedback in the control system. Therefore, the stability and response performance of the system are strongly affected by the delay. At present, there is still no mature way to design controllers for systems with time delay. Although the conventional PID controller used in most practical applications has the capability to comte the delay, the effect of the compensation is limited, especially for the systems with long time delay. Smith predictor, as a compensator for solving this problem, is now widely used in industry systems. However, the request of highly precise model of the system and the poor adaptive performance to the changes of related parameters limit the application of the Smith predictor in practice. In order to overcome the drawbacks of the Smith predictor, a new Smith predictor based on single neural network PID (SNN-PID) is proposed. Because the single neural network is employed into the Smith predictor to improve the controller's self-adaptability, the adaptive capability to the varying parameters of the system is improved. Meanwhile, for the purpose of solving the problems such as time-consuming and complicated calculation of the neural networks in real time, the learning coefficient of neural network is divided into several stages as usually done in expert control system. Therefore, the control system can obtain fast response due to the improved calculation speed of the neural networks. In order to validate the performance of the proposed controller, the

  9. a Numerical Simulation of Strip Profile in a 6-HIGH Cold Rolling Mill

    Science.gov (United States)

    Du, Xiaozhong; Yang, Quan; Lu, Cheng; Tieu, Anh Kiet; Kim, Shinil

    Shape control is always a key issue in the six-high rolling mill, in which the shifting of the intermediate roll and the work roll have been used to enhance the shape control capability. In this paper, a finite element method (FEM) model has been developed to simultaneously simulate the strip deformation and the roll stack deformation for the six-high rolling mill. The effects of the work-roll bending, the shifting of the intermediate roll and the work roll on the strip crown and edge drop are discussed in details. Results have shown that both higher bending force and more roll shifting will significantly reduce the strip crown. The edge drop is also reduced with the bending force and the roll shifting.

  10. Evolution of microstructure and texture during annealing of Al-2.5%Mg-0.2%Sc severely deformed by a combination of accumulative roll bonding (ARB) and conventional rolling

    Science.gov (United States)

    Gatti, J. R.; Bhattacharjee, P. P.

    2015-04-01

    Evolution of microstructure and texture during heavy cold-rolling and annealing of Al-2.5%Mg-0.2%Sc alloy was investigated. For this purpose recrystallized sheets of 1mm thickness having finely dispersed precipitates were processed to 3 cycles of ARB (equivalent strain, εeq=2.4) followed by conventional rolling to a final thickness of 200μm resulting in total equivalent strain of 4.0. Evolution of ultrafine microstructure and strong copper or pure metal type texture were observed during deformation. During annealing very stable microstructure was observed up to 400°C but further annealing resulted in formation of a layered microstructure with deformed layer sandwiched between recrystallized layers. Formation of strong cube texture is not observed in the recrystallized layers. Isothermal annealing for longer time at 500°C leads to abnormal growth of Q orientation ({013}) within the deformed layer.

  11. Microstructural evolution during hot rolling of an AZ31 Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Valle, J.A. del; Perez-Prado, M.T.; Ruano, O.A. [Dept. of Physical Metallurgy, Centro Nacional de Investigaciones Metalurgicas (CENIM), CSIC, Madrid (Spain)

    2003-07-01

    The microstructural evolution of a AZ31 Mg alloy during hot rolling has been investigated using optical microscopy and texture (macro and micro) analysis as the main characterization tools. In particular, the differences between the microstructure obtained by unidirectional rolling (UR) and cross rolling (CR) are studied. Significant twinning activity is observed in both cases. Additionally, after cross rolling, a rather heterogeneous microstructure develops, with scattered regions populated by very fine grains. The strong basal fiber texture of the as-received material remains present after both hot rolling schemes. The impossibility to obtain accurate EBSD measurements within the twinned regions suggests that significant localized deformation takes place in those areas. Thus, these regions become preferential sites for the onset of recrystallization due to the increase in the local strain energy. (orig.)

  12. Effects of Rolling and Cooling Conditions on Microstructure and Mechanical Properties of Low Carbon Cold Heading Steel

    Institute of Scientific and Technical Information of China (English)

    LI Zhuang; WU Di; LV Wei

    2012-01-01

    Effects of rolling and cooling conditions on microstructure and mechanical properties of low carbon cold heading steel were investigated on a laboratory hot rolling mill. The results have shown that the mechanical proper ties of low carbon steels exceed the standard requirements of ML30, ML35, ML40, and ML45 steel, respectively due to thermomechanical controlled processing (TMCP). This is attributed to a significant amount of pearlite and the ferrite-grain refinement. Under the condition of relatively low temperature rolling, the mechanical properties exceed standard requirements of ML45 and ML30 steel after water cooling and air cooling, respectively. Fast cooling which leads to more pearlite and finer ferrite grains is more critical than finish rolling temperatures for low carbon cold heading steel. The specimen at high finish rolling temperature exhibits very good mechanical properties due to fast cooling. This result has great significance not only for energy saving and emission reduction, but also for low-carbon economy, because the goals of the replacement of medium-carbon by low-carbon are achieved with TMCP.

  13. Effect of Cold Rolling and Heat Treatment on the Mechanical Properties of GH4169 Alloy Sheet at Room Temperature

    Directory of Open Access Journals (Sweden)

    Shi-Hong Zhang

    2015-12-01

    Full Text Available The mechanical properties of GH4169 alloy sheet after cold rolling (at 0%, 10%, 30%, 50% and 70% and solid solution were investigated. The textures and Taylor factors were characterized using electron backscattering diffraction (EBSD. The fractions of δ phase were measured by X-ray diffraction. The contributions of δ phase, grain size, texture, and work hardening on the mechanical properties were also discussed. The results showed increases in the yield strength (YS (0.2% as well as the ultimate tensile strength (UTS of GH4169 superalloy sheet after cold rolling, when rolling reduction was increased. In contrast, following solid solution treatment, YS and UTS were increased then subsequently decreased. The changes of yield strength of GH4169 superalloy were attributed to the texture and work hardening, followed by the grain refinement and precipitation of δ phase. When the rolling reduction was below 30%, the influence of δ phase was greater than grain refinement and when the rolling reduction was larger than 50%, the controversial results occur. The precipitation of δ phase promoted the improvement of yield strength, the relationship between the fraction of δ phase and improved yield strength satisfactory fit to the following equation: σδ = 15.9Wδ + 59.7.

  14. Improvement on strip flatness of cold temper mills by modifying roll contour shape

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan Li; Jie Zhang; Xianlin Chen; Jianguo Cao; Haixia Li

    2004-01-01

    A study on roll gap profile (strip profile) control was accomplished in a 1700 mm single-stand temper mill. Some critical problems such as the deviation of work roll contour caused by grinding and wear, the effectiveness of work roll bending were discussed. Using a finite element model, the effects of roll contours (ground and wear) on strip profile were investigated. The roll bending effect on strip thickness was also analyzed. It is pointed out that there are some special features of flatness control in the temper mill: during temper rolling, roll deformation is slight due to small rolling load, and the loaded roll gap profile mainly depends on work roll contour, while the backup roll has a little effect on gap crown; the effect of bending force on gauge can not be ignored due to the coupling between flatness control and gauge control. A new roll contour arrangement adaptable to the mill was presented and has been put into practical production. The application of the new set of rolls showed some good results: larger crown control range of work roll bender, higher rolling stability, better strip profile and flatness quality.

  15. Influence of state of Nb on recrystallization temperature during annealing in cold-rolled low-carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Toshio, E-mail: ogawa.m8b.toshio@jp.nssmc.com [Nagoya Works, Nippon Steel and Sumitomo Metal Corporation, 5-3 Tokai-machi, Tokai-shi, Aichi 476-8686 (Japan); Sugiura, Natsuko [Steel Research Laboratories, Nippon Steel and Sumitomo Metal Corporation, 20-1 Shintomi, Futtsu, Chiba 293-8511 (Japan); Maruyama, Naoki; Yoshinaga, Naoki [Kimitsu R and D Laboratories, Nippon Steel and Sumitomo Metal Corporation, 1 Kimitsu, Kimitsu, Chiba 299-1141 (Japan)

    2013-03-01

    The influence of state of Nb on recrystallization temperature during annealing in cold-rolled low-carbon steels was investigated. Two kinds of specimens showing a remarkable difference in recrystallization temperature were prepared. Differences in the features of Nb-containing precipitates larger than 3 nm were rarely observed, whereas differences in precipitates smaller than 3 nm were confirmed by atom-probe field-ion microscopy in each hot-rolled sheet. The difference in the recrystallization temperatures of both specimens probably originates in the state of Nb at the atomic scale before annealing.

  16. Free-volume evolution and its temperature dependence during rolling of Cu60Zr20Ti20 bulk metallic glass

    DEFF Research Database (Denmark)

    Cao, Q.P.; Li, J.F.; Zhou, Y.H.

    2005-01-01

    The free-volume evolution during rolling Cu60Zr20Ti20 bulk metallic glass at room and cryogenic temperatures has been investigated by differential scanning calorimetry. When the specimen is rolled at cryogenic temperature, the free-volume content increases as the rolling proceeds first...

  17. 连轧机组换辊控制系统的研究与应用%Study and Application of Roll Change Control System in Cold Tandem Rolling Mill

    Institute of Scientific and Technical Information of China (English)

    王亮

    2013-01-01

      介绍某1420 mm 五机架冷连轧生产线换辊控制系统的结构与控制方式。%The article describes the structure and control mode of the roll change control system for a 1420 mm five-stand cold tandem rolling mill.

  18. Cold-rolling behavior of biomedical Ni-free Co-Cr-Mo alloys: Role of strain-induced ε martensite and its intersecting phenomena.

    Science.gov (United States)

    Mori, Manami; Yamanaka, Kenta; Chiba, Akihiko

    2015-03-01

    Ni-free Co-Cr-Mo alloys are some of the most difficult-to-work metallic materials used commonly in biomedical applications. Since the difficulty in plastically deforming them limits their use, an in-depth understanding of their plastic deformability is of crucial importance for both academic and practical purposes. In this study, the microstructural evolution of a Co-29Cr-6Mo-0.2N (mass%) alloy during cold rolling was investigated. Further, its work-hardening behavior is discussed while focusing on the strain-induced face-centered cubic (fcc) γ→hexagonal close-packed (hcp) ε martensitic transformation (SIMT). The planar dislocation slip and subsequent SIMT occurred even in the initial stage of the deformation process owing to the low stability of the γ-phase and contributed to the work hardening behavior. However, the amount of the SIMTed ε-phase did not explain the overall variation in work hardening during cold rolling. It was found that the intersecting of the SIMTed ε-plates enhanced local strain evolution and then produced fine domain-like deformation microstructures at the intersections. Consequently, the degree of work hardening was reduced during subsequent plastic deformation, resulting in the alloy exhibiting a two-stage work hardening behavior. The results obtained in this study suggest that the interaction between ε-martensites, and ultimately its relaxation mechanism, is of significant importance; therefore, this aspect should be addressed in detail; the atomic structures of the γ-matrix/ε-martensite interfaces, the phenomenon of slip transfer at the interfaces, and the slipping behavior of the ε-phase itself are needed to be elucidated for further increasing the cold deformability of such alloys. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Texture evolution and mechanical anisotropy of biomedical hot-rolled Co-Cr-Mo alloy.

    Science.gov (United States)

    Mori, Manami; Yamanaka, Kenta; Sato, Shigeo; Chiba, Akihiko

    2015-11-01

    Crystallographic textures and their effect on the mechanical anisotropy of a hot-rolled biomedical Co-Cr-Mo alloy were investigated. The hot-rolled Co-28Cr-6Mo-0.13N (mass%) alloy examined here exhibited a monotonic strength increment following hot-rolling reduction, eventually reaching a 0.2% proof stress of 1400 MPa while maintaining acceptable ductility (>10%). The dominant hot-rolling texture was a brass-type component, which is characterized by the alloy's peculiarly low stacking fault energy (SFE) even at hot rolling temperatures, although the minor peaks of the near copper component were also identified. However, because of the onset of dynamic recrystallization (DRX) during the hot rolling process, the texture intensity was relatively weak even after 90% hot rolling, although the grain refinement originating from the DRX was not significant (the "less active DRX" condition increased the strain accumulation during the process, resulting in high-strength samples). The weakened texture development resulted in negligible in-plane anisotropy for the hot-rolled specimen strength, when the specimens were tensile strained in the rolling direction (RD) and transverse direction (TD). The elongation-to-failure, however, exhibited a difference with respect to the tensile loading axis. It is suggested that the ductility anisotropy is closely related to a strain-induced γ (fcc) → ε (hcp) martensitic transformation during tensile loading, resulting in a difference in the proportion of quasi-cleavage fracture surfaces. The obtained results will be helpful in the development of high-strength Co-Cr-Mo alloy plates and sheets, and have implications regarding plastic deformation and texture evolution during the hot rolling of non-conventional metallic materials with low SFE at elevated temperatures, where planar dislocation slips of Shockley partial dislocations and thermally activated process interplay.

  20. Heat fluxes and roll circulations over the western Gulf Stream during an intense cold-air outbreak

    Science.gov (United States)

    Chou, Shu-Hsien; Ferguson, Michael P.

    1991-01-01

    Turbulence and heat fluxes in the marine atmospheric boundary layer (MABL) for three aircraft stacks near the western Gulf Stream front, observed during the Genesis of Atlantic Lows Experiment (GALE) January 28, 1986 cold-air outbreak, has been studied using mixed-layer scaling. The GOES image and stability parameter indicates that these three stacks were in the roll vortex regime. The turbulence structure in the MABL is studied for this case, as well as the significance of roll vortices to heat fluxes. The roll circulations are shown to contribute significantly to the sensible (temperature) and latent heat (moisture) fluxes with importance increasing upward. The results suggest that the entrainment at the MABL top might affect the the budgets of temperature and humidity fluxes in the lower MABL, but not in the unstable surface layer.

  1. Effect of annealing prior to cold rolling on magnetic and mechanical properties of low carbon non-oriented electrical steels

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Castaneda, E.J., E-mail: emmanuel.gutierrez@yahoo.com.mx [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional (CINVESTAV-IPN), Department of Metallurgical Engineering and Materials Science, Carretera Saltillo-Monterrey, Km 13.5, 25900 Ramos Arizpe, Coahuila, P.O. Box 663, Saltillo Coahuila, 25000 (Mexico); Salinas-Rodriguez, A., E-mail: armando.salinas@cinvestav.edu.mx [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional (CINVESTAV-IPN), Department of Metallurgical Engineering and Materials Science, Carretera Saltillo-Monterrey, Km 13.5, 25900 Ramos Arizpe, Coahuila, P.O. Box 663, Saltillo Coahuila, 25000 (Mexico)

    2011-10-15

    The effects of annealing prior to cold rolling on the microstructure, magnetic and mechanical properties of low-C grain non-oriented (GNO) electrical steels have been investigated. The grain structure of hot-rolled electrical steel strips is modified by annealing at temperatures between 700 and 1050 deg. C. Annealing at temperatures less than the ferrite to austenite+ferrite transformation temperature on heating (Ac{sub 1}) causes a marginal effect on the grain size. However, annealing in the intercritical region at temperatures between Ac{sub 1} and Ac{sub 3} (the ferrite+austenite to austenite transformation temperature on heating) causes rapid decarburization and development of large columnar ferrite grains free of carbide particles. This microstructure leads, after cold rolling and a fast annealing treatment, to carbide free, large ferrite grain microstructures with magnetic and mechanical properties superior to those observed typically in the same steel in the industrially fully processed condition. These results are attributed to the increment in grain size and to the {l_brace}1 0 0{r_brace} fiber texture developed during the final annealing at temperatures up to 850 deg. C. Annealing at higher temperatures, T>Ac{sub 3}, results in a strong {l_brace}1 1 1{r_brace} fiber texture and an increase of the quantity of second phase particles present in the microstructure, which lead to a negative effect on the final properties. The results suggest that annealing prior to cold rolling offers an attractive alternative processing route for the manufacture of fully processed low C GNO electrical steels strips. - Highlights: > Electrical steels are produced by an alternative processing route. > Annealing of the hot rolled electrical steel strips causes rapid decarburization. > Development of the <1 0 0>//ND texture results in better magnetic properties. > Magnetic properties of electrical steels depend on the grain size and texture. > Second phase particles and grain

  2. Effect of severe plastic deformation on the specific heat and magnetic properties of cold rolled Gd sheets

    Science.gov (United States)

    Taskaev, S.; Skokov, K.; Khovaylo, V.; Buchelnikov, V.; Pellenen, A.; Karpenkov, D.; Ulyanov, M.; Bataev, D.; Usenko, A.; Lyange, M.; Gutfleisch, O.

    2015-03-01

    We report on specific heat and magnetic properties of thin Gd sheets obtained by means of a cold rolling technique. At temperatures well below Curie temperature TC, the cold rolling has a minor impact on the specific heat Cp. However, a well defined λ-type anomaly of Cp seen in the vicinity of TC in a polycrystalline Gd sample is markedly suppressed in the severely deformed samples. Depression of the λ peak is due to a large decrease of magnetization that presumably originates in a local magnetic anisotropy induced by the severe plastic deformation. Results of calculation of magnetocaloric effect from the Cp and magnetization data indicate that the magnetocaloric effect gradually decreases as the degree of plastic deformation increases. This trend is further confirmed by the direct measurements of the adiabatic temperature change ΔTad.

  3. Application of a new feature extraction and optimization method to surface defect recognition of cold rolled strips

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Considering that the surface defects of cold rolled strips are hard to be recognized by human eyes under high-speed circumstances, an automatic recognition technique was discussed. Spectrum images of defects can be got by fast Fourier transform (FFT) and sum of valid pixels (SVP), and its optimized center region, which concentrates nearly all energies, are extracted as an original feature set. Using genetic algorithm to optimize the feature set, an optimized feature set with 51 features can be achieved.Using the optimized feature set as an input vector of neural networks, the recognition effects of LVQ neural networks have been studied. Experiment results show that the new method can get a higher classification rate and can settle the automatic recognition problem of surface defects on cold rolled strips ideally.

  4. Performance Optimization of Cold Rolled Type 316L Stainless Steel by Sand Blasting and Surface Linishing Treatment

    Science.gov (United States)

    Krawczyk, B.; Heine, B.; Engelberg, D. L.

    2016-03-01

    Sand blasting followed by a surface linishing treatment was applied to optimize the near-surface microstructure of cold rolled type 316L stainless steel. The introduction of cold rolling led to the formation of α-martensite. Specimens with large thickness reductions (40, 53%) were more susceptible to localized corrosion. The application of sand blasting produced a near-surface deformation layer containing compressive residual stresses with significantly increased surface roughness, resulting in reduced corrosion resistance. The most resistant microstructure was obtained with the application of a final linishing treatment after sand blasting. This treatment produced microstructures with compressive near-surface residual stresses, reduced surface roughness, and increased resistance to localized corrosion.

  5. Two pyrazine derivatives as inhibitors of the cold rolled steel corrosion in hydrochloric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Deng Shuduan, E-mail: dengshuduan@163.co [Faculty of Wood Science and Decoration Technology, Southwest Forestry University, Kunming 650224 (China); Li Xianghong; Fu Hui [Department of Fundamental Courses, Southwest Forestry University, Kunming 650224 (China)

    2011-02-15

    Research highlights: Two pyrazine derivatives of 2-aminopyrazine (AP) and 2-amino-5-bromopyrazine (ABP) are good inhibitors for the corrosion of steel in 1.0 M HCl solution. The inhibition efficiency follows the order: ABP > AP. The substitution Br of ABP is the additional centre of adsorption and increases the electron density of pyrazine ring, which can facilitate its adsorption on the metal surface. For either ABP or AP, the adsorption obeys Langmuir adsorption isotherm. Both ABP and AP act as mixed-type inhibitors. - Abstract: The inhibition effect of two pyrazine derivatives of 2-aminopyrazine (AP) and 2-amino-5-bromopyrazine (ABP) on the corrosion of cold rolled steel (CRS) in 1.0 M hydrochloric acid (HCl) was studied by weight loss, potentiodynamic polarization curves, and electrochemical impedance spectroscopy (EIS) methods. The results show that both AP and ABP are good inhibitors, and inhibition efficiency follows the order: ABP > AP. The adsorption of each inhibitor on CRS surface obeys Langmuir adsorption isotherm. Potentiodynamic polarization curves show that two pyrazine derivatives act as mixed-type inhibitors. EIS spectra exhibit one capacitive loop and confirm the inhibitive ability.

  6. Influence of stress path change on the resistance to plastic deformation of cold rolled sheets

    Institute of Scientific and Technical Information of China (English)

    Zonghai Ding; Pavel Huml

    2005-01-01

    Flat workpieces have been tested in order to investigate the influence of stress path change (loading mode) while keeping strain path unchanged. These investigations are pertinent to the testing of cold rolled strips and to subsequent forming. The workpieces which first compressed by plane strain compression in thickness direction were then tested in perpendicular direction in order to measure the influence of strain and stress path. The tension workpieces came from flat die compression test at different deformation histories. Two different materials were investigated: 18/8 Ti stainless steel and AW-1050 aluminium. The results show that the plastic flow by tension in lengthwise direction after pre-strain by compression in thickness direction will begin at an appreciably lower stress than that of the workpieces unloaded after pre-compression. Comparing with two materials, it can be seen that both 18/8Ti stainless steel and AW-1050 aluminium behave similarly. The drop in yield stress is lower for AW-1050 aluminium than that for 18/8 Ti stainless steel. However, reloading in different directions than in the precious step results in significantly higher strain hardening.

  7. Elimination of Lubricants from Aluminum Cold Rolled Products Using Short Laser Pulses

    Directory of Open Access Journals (Sweden)

    Lima M.S.F.

    2002-01-01

    Full Text Available This work presents a new technique to remove the surface impurities from the aluminum cold-worked sheets. The method consists to concentrate a short-time high-power pulsed laser on the materials surface and scan it in order to cover a desired area. Incrustations ablation is obtained as long as the fluency and the peak power are high enough to produce vaporization of the contaminated layer without affecting the material surface properties. The present problem consists in eliminating a desiccated soap of about 1 g/m² from the surface of a 6016-class aluminum alloy sheet. The soap is originated from the rolling process. The present laser method is intended to replace water washing when the piece cannot be soaked, when drying is difficult due to the geometry, or when environmental restrictions apply. Best results were obtained when the pulse length was 100 ns and the average laser power was 95 W. In these conditions, the surface was completely cleaned and the aluminum alloy did not suffer any structural modification.

  8. Effect of SiC Nanoparticles on Bond Strength of Cold Roll Bonded IF Steel

    Science.gov (United States)

    Jamaati, Roohollah; Toroghinejad, Mohammad Reza; Edris, Hossein

    2013-11-01

    In this study, cold roll bonding process characteristics of IF steel strips, such as bond strength, threshold deformation, undulation of peeling force, and peeled surface, in the presence of SiC nanoparticles were examined and compared to those of an IF steel strip without nanoparticles. The bond strength was evaluated by the peeling test and scanning electron microscopy. It was found that when the thickness reduction was increased, the peeling force of IF steel strips improved. The results also indicated that the presence of silicon carbide nanoparticles decreased the bond strength of IF steel strips when compared to the strips without nanoparticles for the same thickness reduction. When the thickness reduction was increased, the undulation of average peeling force values increased at a constant nanoparticle content. Also, the strips without nanoparticles had a lower undulation value as compared to the strips with SiC nanoparticles. In addition, in the presence of silicon carbide, when the nanoparticles' content was increased, the undulation of average peeling force values decreased at a constant thickness reduction. Finally, it was found that the bond strength of IF steel strips was less than that of aluminum and copper strips. This was attributed to their crystal structure.

  9. Characterization of a cold-rolled 2101 lean duplex stainless steel.

    Science.gov (United States)

    Bassani, Paola; Breda, Marco; Brunelli, Katya; Mészáros, Istvan; Passaretti, Francesca; Zanellato, Michela; Calliari, Irene

    2013-08-01

    Duplex stainless steels (DSS) may be defined as a category of steels with a two-phase ferritic-austenitic microstructure, which combines good mechanical and corrosion properties. However, these steels can undergo significant microstructural modification as a consequence of either thermo-mechanical treatments (ferrite decomposition, which causes σ- and χ-phase formation and nitride precipitation) or plastic deformation at room temperature [austenite transformation into strain-induced martensite (SIM)]. These secondary phases noticeably affect the properties of DSS, and therefore are of huge industrial interest. In the present work, SIM formation was investigated in a 2101 lean DSS. The material was subjected to cold rolling at various degrees of deformation (from 10 to 80% thickness reduction) and the microstructure developed after plastic deformation was investigated by electron backscattered diffraction, X-ray diffraction measurements, and hardness and magnetic tests. It was observed that SIM formed as a consequence of deformations higher than ~20% and residual austenite was still observed at 80% of thickness reduction. Furthermore, a direct relationship was found between microstructure and magnetic properties.

  10. Effects of microstructure on fatigue crack growth behavior in cold-rolled dual phase steels

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shengci [School of Materials Science and Engineering, State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Kang, Yonglin, E-mail: kangylin@ustb.edu.cn [School of Materials Science and Engineering, State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Kuang, Shuang [Technical Research Institute, Shougang Corporation, Ltd., Beijing 100043 (China)

    2014-08-26

    Fatigue crack growth behaviors of cold-rolled dual phase steels with different microstructures were investigated at room temperature. The ferrite–martensite dual-phase microstructure was obtained by intercritical annealing. Fatigue crack growth (FCG) behaviors were described by both the Paris model and a new exponential model; fatigue fractography and surface morphology near the fracture were arrested by scanning electron microscopy (SEM); the relationship between macroscopic and microcosmic FCG rate was analyzed quantificationally. The results showed that both the models can be used to describe the fatigue crack growth rate of the samples rather well; fatigue striations and secondary cracks were observed in the fracture surface at stable expanding region (II), while the fracture at rapid expanding region (III) combined dimple and quasi-cleavage morphology; the roughness of fracture surface and the degree of secondary cracking increased with an increase in martensite content, leading to a higher threshold value. Moreover, the changes of microcosmic FCG rate were smoother than that of the macroscopic FCG rate.

  11. FINITE ELEMENT ANALYSIS FOR MICROSTRUCTURE EVOLUTION IN HOT FINISHING ROLLING OF STEEL STRIPS

    Institute of Scientific and Technical Information of China (English)

    Z.D. Qu; S.H. Zhang; D.Z. Li; Z.T. Wang

    2007-01-01

    A computer model that describes the evolution of microstructures during the hot finishing rolling of SS400 steel has been proposed. It has been found that the microstructure strongly depends on processing of materials and on their parameters, which affected the history of the thermomechanical variables, such as temperature, strain, and strain rate. To investigate the microstructural evolutions during the hot finishing rolling process, the rigid-thermoviscoplastic finite element method (FEM)has been combined with dynamic recrystallization, static recrystallization, and grain growth models.The simulation results show a good agreement with those from the prediction software online.

  12. DNN-Based ADNMPC of an Industrial Pickling Cold-Rolled Titanium Process via Field Enhancement Heat Exchange

    OpenAIRE

    Biao Yang; Jinhui Peng; Wei Li; Youling Li; Huilong Luo; Zhuming Zhang; Shenghui Guo; Shimin Zhang; Hezhou Su; Yaming Shi

    2015-01-01

    The dynamic neural network based adaptive direct nonlinear model predictive control is designed to control an industrial microwave heating pickling cold-rolled titanium process. The identifier of the direct adaptive nonlinear model identification and the controller of the adaptive nonlinear model predictive control are designed based on series-parallel dynamic neural network training by RLS algorithm with variable incremental factor, gain, and forgetting factor. These identifier and controlle...

  13. Finite Element Simulation of Hot Strip Continuous Rolling Process Coupling Microstructural Evolution

    Institute of Scientific and Technical Information of China (English)

    WANG Min-ting; ZANG Xin-liang; LI Xue-tong; DU Feng-shan

    2007-01-01

    Using the nonlinear rigid-viscoplastic finite element method (FEM), a finite element simulation of the hot strip continuous rolling process was done, which completely integrates different phenomena such as the metallurgical behavior of the strip and the thermo-mechanics in the strip based on the physical metallurgical microstructural evolution law. By combining with the process parameters of certain 2 050 mm hot strip rolling, an actual rolling process of low carbon steel SS400 was simulated using the FEM model. Based on the simulation results, the distributions of the strain field, the temperature field, and the microstructure were presented. Meanwhile, the simulated rolling force, temperature, and microstructure are in good agreement with the measured results.

  14. Influence of electropulsing treatment on microstructure and mechanical properties of cold-rolled Mg-9Al-1Zn alloy strip

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Yanbin [Key Laboratory for Advanced Materials Processing (MOE), University of Science and Technology Beijing, Beijing 100083 (China); Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083 (China); Guan Lei [Laboratory of Structural Steel, Functional Materials and Heat Treatment Processing Technology, Institute of Aeronautical Materials, Beijing 100095 (China); Tang Guoyi, E-mail: tanggy@mail.tsinghua.edu.cn [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Shek, Chanhung [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong (Hong Kong); Zhang Zhihao [Key Laboratory for Advanced Materials Processing (MOE), University of Science and Technology Beijing, Beijing 100083 (China); Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083 (China)

    2011-06-25

    Highlights: {yields} EPT tremendously accelerated recrystallization of cold-rolled AZ91 alloy. {yields} The extent of EPT induced recrystallization increased gradually with frequency. {yields} EPT changed the tensile fracture behaviours of the AZ91 strip. {yields} A mechanism for rapid recrystallization of the AZ91 alloy under EPT was proposed. - Abstract: Influences of electropulsing treatment (EPT) on microstructure and mechanical properties of cold-rolled Mg-9Al-1Zn alloy strip were studied. EPT was found to accelerate the recrystallization of cold-rolled Mg-9Al-1Zn alloy strip at a relatively low temperature, and obtain fine microstructure of quasi-single-phase-recrystallized grains. The EPT-induced microstructural changes weakened the intensity of the basal fiber texture, and increased elongation to failure remarkably with a decrease in tensile strength. Fracture surface analysis showed that transition from intergranular brittle facture to transgranular dimple fracture took place with an increase in frequency of EPT. The rapid recrystallization behaviour of the Mg-9Al-1Zn alloy strip under EPT was attributed to the enhancement of nucleation rate and atomic diffusion resulting from the coupling of the thermal and athermal effects. It is supposed that EPT can provide a highly efficient method for the intermediate-softening annealing of magnesium alloys sheet/strips.

  15. Effects of Cold Rolling and Strain-Induced Martensite Formation in a SAF 2205 Duplex Stainless Steel

    Science.gov (United States)

    Breda, Marco; Brunelli, Katya; Grazzi, Francesco; Scherillo, Antonella; Calliari, Irene

    2015-02-01

    Duplex stainless steels (DSSs) are biphasic steels having a ferritic-austenitic microstructure that allows them to combine good mechanical and corrosion-resistance properties. However, these steels are sensitive to microstructural modifications, such as ferrite decomposition at high temperatures and the possibility of strain-induced martensite (SIM) formation from cold-worked austenite, which can significantly alter their interesting features. In the present work, the effects of cold rolling on the developed microstructural features in a cold-rolled SAF 2205 DSS and the onset of martensitic transformation are discussed. The material was deformed at room temperature from 3 to 85 pct thickness reduction, and several characterization techniques (scanning and transmission electron microscopy, X-ray diffraction, hardness measurements, and time-of-flight-neutron diffraction) were employed in order to fully describe the microstructural behavior of the steel. Despite the low stacking fault energy of DSS austenite, which contributed to SIM formation, the steel was found to be more stable than other stainless steel grades, such as AISI 304L. Rolling textures were similar to those pertaining to single-phase materials, but the presence of the biphasic (Duplex) microstructure imposed deformation constraints that affected the developed microstructural features, owing to phases interactions. Moreover, even if an intensification of the strain field in austenite was revealed, retarded SIM transformation kinetics and lower martensite amounts with respect to AISI 304L were observed.

  16. Investigation of cold rolling influence on the mechanical properties of explosive-welded Al/Cu bimetal

    Energy Technology Data Exchange (ETDEWEB)

    Asemabadi, M. [School of Mechanical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16844 (Iran, Islamic Republic of); Sedighi, M., E-mail: sedighi@iust.ac.ir [School of Mechanical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16844 (Iran, Islamic Republic of); Honarpisheh, M. [School of Mechanical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16844 (Iran, Islamic Republic of)

    2012-12-15

    In this study, effect of cold rolling process on the mechanical properties and bond strength of Al/Cu/Al bimetal has been investigated. The bimetal raw material has been fabricated by the explosive welding process. Then, cold rolling process was used to reduce the thickness of explosive-welded plates. The mechanical properties of the raw materials and cold-rolled samples were experimentally measured using the tensile, tensile-shearing and hardness tests along the thicknesses of the samples. Moreover, the fractography of the surfaces after the tensile tests were examined by the electron microscope (SEM). The obtained results show that, with the increase of thickness reduction, the ultimate strength and hardness have been increased significantly, while the elongation percentage has been diminished. Also, the bond strength confirms the relevant known standard criterion which is higher than the strength of the aluminum layers. Examination of the fracture surfaces reveal that, due to the brittle nature of the intermetallic compounds at the joining interface, the nucleation and propagation of micro cracks have been accelerated under tension and plastic deformation.

  17. Influence of the placement of a previously derived ellipse shaped aperture in the starting material on the processing with drawing of the cold rolled sheet steels

    OpenAIRE

    Cvetkov, Slavco; Simeonov, Simeon; Dimitrov, Sasko

    2011-01-01

    In this paper, a research of the impact of the position regarding the main directions of the plane anisotropy of previously derived ellipse shaped aperture (opening) in starting material on the workability of the drawn cold rolled sheet steel is made. This influence is researched using hydraulic drawing of cold rolled sheet steel with previous derived ellipse shaped openings placed in the directions of plane anisotropy. The research aims to show how the position of the previous derived el...

  18. Influence of the finish rolling temperatures on the microstructure and texture evolution in the ferritic stainless steels

    Institute of Scientific and Technical Information of China (English)

    Fei GAO; Zhen yu LIU; Haitao LIU; Guodong WANG

    2011-01-01

    The influence of the finish rolling temperature on the microstructure and texture evolution of Nb and B micro-alloyed ultra purified Cr17 ferritic stainless steels was investigated.The hot rolled bands were produced by conventional rolling process and the finish rolling at relatively low temperatures or “warm rolling”.The microstructure was observed by optical microscopy,scanning electron microscopy and transmission electron microscopy,and X-ray diffraction was used to characterize the texture evolution processes.The results showed that as compared to conventional hot rolling process,the warm rolling has led to the refined and homogeneous microstruc ture and uniform recrystallization texture along γ-fiber in final sheets,indicating that the finish rolling at relatively low temperatures can be the effective way to improve significantly the formability of final sheets.

  19. Microstructure, cold rolling, heat treatment, and mechanical properties of Mg-Li alloys

    Institute of Scientific and Technical Information of China (English)

    Haibin Ji; Guangchun Yao; Hongbin Li

    2008-01-01

    The magnesium-lithium (Mg-Li) alloy exhibits two phase structures between 5.7wt% and 10.3wt% Li contents, consisting of the a (hcp) Mg-rich and the β (bee) Li-rich phases, at room temperature. In the experiment, Mg-5Li-2Zn, Mg-9Li-2Zn,Mg-16Li-2Zn, Mg-22Li-2Zn, Mg-5Li-2Zn-2Ca, Mg-9Li-2Zn-2Ca, Mg-16Li-2Zn-2Ca, and Mg-22Li-2Zn-2Ca (wt%) were melted.During the melting process, the flux, which was composed of lithium chloride (LiCI) and lithium fluoride (LiF) in the proportion of 3:1 (mass ratio) and argon gas were used to protect the alloys from oxidation. The mierostructure, mechanical properties, and cold-rolling workability of the wrought alloys were studied. The crystal grain of the alloys (adding Ga) is fine. The hardness of the studied alloys decreases with an increase in element Li. The density of the studied alloys is in the range of 1.187 to 1.617 g/cm3 The reduction of the Mg-16Li-2Zn and Mg-22Li-2Zn alloys can exceed 85% at room temperature. The Mg-9Li-2Zn-2Ca alloy was heat treated at 300℃ for 8, 12, 16, and 24 h, respectively. The optimum heat treatment of the Mg-9Li-2Zn-2Ca alloy is 300~Cx12h by metallographic observation and by studying the mechanical properties of the alloys.

  20. Online Prediction Under Model Uncertainty via Dynamic Model Averaging: Application to a Cold Rolling Mill.

    Science.gov (United States)

    Raftery, Adrian E; Kárný, Miroslav; Ettler, Pavel

    2010-02-01

    We consider the problem of online prediction when it is uncertain what the best prediction model to use is. We develop a method called Dynamic Model Averaging (DMA) in which a state space model for the parameters of each model is combined with a Markov chain model for the correct model. This allows the "correct" model to vary over time. The state space and Markov chain models are both specified in terms of forgetting, leading to a highly parsimonious representation. As a special case, when the model and parameters do not change, DMA is a recursive implementation of standard Bayesian model averaging, which we call recursive model averaging. The method is applied to the problem of predicting the output strip thickness for a cold rolling mill, where the output is measured with a time delay. We found that when only a small number of physically motivated models were considered and one was clearly best, the method quickly converged to the best model, and the cost of model uncertainty was small; indeed DMA performed slightly better than the best physical model. When model uncertainty and the number of models considered were large, our method ensured that the penalty for model uncertainty was small. At the beginning of the process, when control is most difficult, we found that DMA over a large model space led to better predictions than the single best performing physically motivated model. We also applied the method to several simulated examples, and found that it recovered both constant and time-varying regression parameters and model specifications quite well.

  1. Tribology and Tool Wear of Hot Dip Galvanized Zinc Magnesium Alloys on Cold Rolled Steel Sheets

    Science.gov (United States)

    Raab, A. E.; Berger, E.; Freudenthaler, J.; Leomann, F.; Walch, C.

    2011-05-01

    Recently zinc based coatings on cold rolled steel with improved functionality in terms of forming and/or corrosion behaviour have been intensively investigated in the steel industry1,2,3. One of the most promising products are zinc magnesium alloys produced in hot dip galvanizing process. These coatings were already introduced in construction industry a few years ago1. With some modifications the improved properties of the coating are also interesting for automotive industry. In the present work the tribological potential of hot dip galvanized zinc magnesium coatings (HDG/ZM) produced at an industrial line under regular production, was studied in terms of sliding properties, adhesive and abrasive tool wear. First a short introduction into surface morphology of HDG/ZM will be given. For the tribological characterization of the material, which is the main topic of the contribution, different tests were performed on hot dip galvanised zinc magnesium material and results were compared with classic hot dip galvanized zinc coating (HDG/Z). The investigations are mainly based on the strip draw test which allows the determination of the friction coefficient directly by using a constant contact pressure. Deep drawing property was tested by forming model cups. The abrasive tool wear was tested using a standard test for material used in automotive industry. The adhesive tool wear was investigated by characterizing the coating material transferred to the tool in the strip draw test. All performed tests show an improved drawability of HDG/ZM compared to classical HDG/Z reference material. However the most promising difference between HDG/ZM and HDG/Z is that galling was found to be less for HDG/ZM than for HDG/Z. Therefore HDG/ZM is an interesting system not only with respect to corrosion protection but also in terms of tribology and provides clear advantages in formability.

  2. Effects of induced shear deformation on microstructure and texture evolution in CP-Ti rolled sheets

    Energy Technology Data Exchange (ETDEWEB)

    Milner, Justin L. [Department of Automotive Engineering, Clemson University, Greenville, SC 29607 (United States); Abu-Farha, Fadi, E-mail: FADI@clemson.edu [Department of Automotive Engineering, Clemson University, Greenville, SC 29607 (United States); Kurfess, Thomas [School of Mechanical Engineering, Georgia Institute of Technology, GA 30332 (United States); Hammond, Vincent H. [US Army Research Laboratory, Aberdeen Proving Ground, MD 21005 (United States)

    2014-12-01

    Commercial pure titanium sheets were deformed by shear rolling at 400 °C with subsequent annealing to investigate microstructure and texture evolution along with its effects on the mechanical properties. A four sheet multilayer rolling scheme was used to isolate shear strains within the outer sheets, termed isolated shear rolling (ISR), thus allowing for direct comparison between shear strained material (outer sheets) and plane-strained material under similar conditions. Microstructure and texture evolution were investigated by electron backscatter diffraction analysis, while mechanical properties were evaluated through tensile testing aided by digital image correlation (DIC). Texture was seen to evolve from a ±30° transverse direction (TD) split basal texture to primarily basal texture (〈0001〉//Normal Direction) for the shear-strained sheets, in comparison with a slight rotation to a ±20° TD-split for the plane-strained sheets. After short-term annealing at 600 °C for 15 min, texture remained similar to that of the as-processed material yet at lower intensity levels. Compared to the base material, shear-rolled material showed much higher Lankford Coefficient values, with a significant boost attributed to shear deformation. The greater stretch formability is achieved in the shear-rolled material by rotation of the basal poles to become parallel to the sheet thickness. The results obtained here with ISR in regards to the effects of inducing higher shear strains on the rolled material are comparable to those reported in the literature by differential speed rolling (DSR)

  3. Microstructural Evolution of a Hypoeutectoid Pearlite Steel under Rolling-sliding Contact Loading

    Institute of Scientific and Technical Information of China (English)

    Qiu-han LI; Chi ZHANG; Hu CHEN; Hao CHEN; Zhi-gang YANG

    2016-01-01

    To study the microstructural evolution of pearlite steel subj ected to pure rolling and rolling-sliding contact loading,a hypoeutectoid pearlite steel with composition and microstructure similar to BS1 1 was designed and twin-disc tests of this pearlite steel were performed to simulate the wheel/rail system.After a series of twin-disc tests, optical microscope (OM)observation,scanning electron microscope (SEM)observation,X-ray diffraction (XRD), and micro-hardness tests were conducted to characterize the microstructure.Under the pure rolling contact condition, a large amount of reticular cracks emerged within 60μm below the contact surface of the samples after 120 000 revo-lutions.The largest deformation was approximately 200μm below the contact surface.Under the rolling-sliding con-tact condition,the nodularization of pearlite within 100μm below the contact surface was obvious.The microstruc-ture and stress-strain distribution of the area within 2 mm below the contact surface were investigated.The distribu-tion of micro-hardness under the contact surface varied with contact conditions.Finite element method (FEM)was used to simulate the stress-strain distribution.The results of SEM,FEM,and micro-hardness tests indicated that under the pure rolling contact condition,the maximum plastic strain was approximately 200-400μm below the con-tact surface.Conversely,under the rolling-sliding contact condition,the maximum plastic strain emerged on the con-tact surface.Under the pure rolling contact condition,the distribution of micro-hardness was almost identical to that of the equivalent plastic strain.Under the rolling-sliding contact condition,the distribution of micro-hardness was af-fected by the equivalent plastic strain and tangential stress.

  4. Precipitation in cold-rolled Al-Sc-Zr and Al-Mn-Sc-Zr alloys prepared by powder metallurgy

    KAUST Repository

    Vlach, Martin

    2013-12-01

    The effects of cold-rolling on thermal, mechanical and electrical properties, microstructure and recrystallization behaviour of the AlScZr and AlMnScZr alloys prepared by powder metallurgy were studied. The powder was produced by atomising in argon with 1% oxygen and then consolidated by hot extrusion at 350 C. The electrical resistometry and microhardness together with differential scanning calorimetry measurements were compared with microstructure development observed by transmission and scanning electron microscopy, X-ray diffraction and electron backscatter diffraction. Fine (sub)grain structure developed and fine coherent Al3Sc and/or Al3(Sc,Zr) particles precipitated during extrusion at 350 C in the alloys studied. Additional precipitation of the Al3Sc and/or Al3(Sc,Zr) particles and/or their coarsening was slightly facilitated by the previous cold rolling. The presence of Sc,Zr-containing particles has a significant antirecrystallization effect that prevents recrystallization at temperatures minimally up to 420 C. The precipitation of the Al6Mn- and/or Al 6(Mn,Fe) particles of a size ~ 1.0 μm at subgrain boundaries has also an essential antirecrystallization effect and totally suppresses recrystallization during 32 h long annealing at 550 C. The texture development of the alloys seems to be affected by high solid solution strengthening by Mn. The precipitation of the Mn-containing alloy is highly enhanced by a cold rolling. The apparent activation energy of the Al3Sc particles formation and/or coarsening and that of the Al6Mn and/or Al 6(Mn,Fe) particle precipitation in the powder and in the compacted alloys were determined. The cold deformation has no effect on the apparent activation energy values of the Al3Sc-phase and the Al 6Mn-phase precipitation. © 2013 Elsevier Inc.

  5. Applicability of the laws of elasticity for the determination of the elastic-region length in the deformation zone during cold rolling

    Science.gov (United States)

    Garber, E. A.; Shalaevskii, D. L.; Kozhevnikova, I. A.; Traino, A. I.

    2008-06-01

    The errors of calculating the energy-force parameters of cold rolling are analyzed. They appear because of the assumption of the classic rolling theory about the applicability of the Hertz formula, which is known in the theory of elasticity, to the calculation of the elastic-region length in the deformation zone. The Hertz formula, which is used to calculate the half-width of the contact area between a fixed cylinder and a plane that bounds an elastic half-space, is shown not to take into account the following factors that are characteristic and important for the roll-strip contact: the cold working of the strip, the strip thickness, the rotation of rolls accompanied by sliding friction, and the wear that decreases the initial roll roughness (i.e., changes in the friction coefficient). A method is proposed for taking into account these factors in the calculation of the energy-force parameters of cold rolling; it is based on the statistical processing of the parameters that are measured in operating mills and are present in the databases of their process control systems. The application of this method decreases the errors of calculating the rolling forces by 35 40% and refines some laws of the state of stress in a rolled strip.

  6. Analysis of the cause of crack in cold rolling of QSn6.5-0.1 strip

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to know the cause of cracks in cold rolling of QSn6.5-0.1 copper alloy strip, a lot of experiments and analysis were done. The microstructure changes of QSn6.5-0.1 were investigated by means of metallurgical microscope. The morphology of cracks and surface defects were examined using scanning electron microscope. Macroscopic residual stresses produced in every process during manufacturing in the QSn6.5-0.1 strip were measured by X-ray diffraction method and hole drilling method. The results show that the cracks in the QSn6.5-0.1 cold rolling strip were caused due to the derivation of metallurgical defects, such as SnO2, S, fine-looses,the inverse segregation unable to clear up when milling, and the accumulation of all kinds of resi-dual stresses. When the accumulation of the residual stress reaches the material′s breaking strength, the cracks will be generated. Several measures to avoid the development of these kinds of cracks were put forward, such as: controlling the casting technology, improving homogenization annealing procedure (680 ℃/7 h) and milling quality(using the second milling when necessary), working out a more reasonable rolling technology to ensure intermediate annealing in time.

  7. Magnet properties of Mn{sub 70}Ga{sub 30} prepared by cold rolling and magnetic field annealing

    Energy Technology Data Exchange (ETDEWEB)

    Ener, Semih, E-mail: ener@fm.tu-darmstadt.de [Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Skokov, Konstantin P. [Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Karpenkov, Dmitriy Yu. [Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Faculty of Physics, Tver State University, 170100 Tver (Russian Federation); Immanuel Kant Baltic Federal University, 236041 Kaliningrad (Russian Federation); Kuz' min, Michael D. [Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Gutfleisch, Oliver [Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Fraunhofer IWKS, Project Group for Material Cycles and Resource Strategy, 63457 Hanau (Germany)

    2015-05-15

    The remanence and coercivity of arc melted Mn{sub 70}Ga{sub 30} can be substantially improved by cold rolling. For best performance the rolled material should be annealed at T=730 K in the presence of a magnetic field of 1 T. The so-obtained magnet has a remanence of 0.239 T and a coercivity of 1.24 T at room temperature. The underlying reason for the high coercivity and remanence is the increase of the content of a metastable ferrimagnetic D0{sub 22} phase at the expense of the normally stable anti-ferromagnetic D0{sub 19}. Magnetic field significantly increases the nucleation rate of the ferromagnetic D0{sub 22} phase that leads to grain size refinement and as a consequence of improving remanence and coercive field. - Highlights: • Alternative synthesis method for D0{sub 22} phase formation in Mn–Ga is developed. • Effect of cold rolling and annealing on magnetic properties of Mn{sub 70}Ga{sub 30} is examined. • Small magnetic fields are sufficient to accelerate nucleation of the D0{sub 22} phase.

  8. Preparation and Lubricating Properties of A New Antibacterial Emulsion Containing Nano-TiO2 for Cold Rolling Strips

    Institute of Scientific and Technical Information of China (English)

    Lu Yudi; Sun Jianlin; Zhang Bingtao

    2016-01-01

    A new kind of emulsion containing nano TiO2was developed through the dispersion experiment. A commercial emulsion and a prepared by our lab emulsion without nano particles were chosen as controls to test the tribological and antibacterial properties of this new emulsion. The load carrying capacity, friction coefficient and average diameter of wear scars were tested by a four-ball machine and the comprehensive antifriction parameterω was calculated. The wetting angle was also tested using a JC200C1 wetting angle tester. The micro surface and roughness of rolled strips were analyzed to investigate the tribological performance of the recommended new emulsion in strip production. It is shown that the new nano-emulsion possesses a higher load carrying capacity and wetting ability. Therefore the abrasive/plowing wear is re-duced more efficiently with the addition of nano particles, and the micro surface is improved. The density of bacteria in the emulsions was tested after the cold rolling experiment. The emulsion breaking ratio and bacteria density were also tested in different time intervals after the cold rolling experiment. The final pH values and bacteria density of different layers of emulsions were measured and the sediment was analyzed by TEM to evaluate the antibacterial behavior of this new emul-sion. It is shown that the density of microbial colonies which led to a corruption of emulsions was decreased about 90% and the effective antibacterial period was prolonged.

  9. Simulation of two Stands Cold Rolling Mill Process Using a Combination of Neural Networks and Genetic Algorithms to Avoid the Chatter Phenomenon

    Directory of Open Access Journals (Sweden)

    Behzad BahramiNejad

    2015-03-01

    Full Text Available Rolling mill Industry is one of the most profitable industries in the world. Chatter phenomenon is one of the key issues in this industry. Chatter or rolling unwanted vibrations not only has an adverse effect on product quality, but also reduces considerably the efficiency with reduced rolling velocities of rolling lines. This paper is an attempt to simulate the phenomenon of Chatter more accurate than the previous performed simulations. In order to increase the production speed, it needs to avoid parameters which effect on the Chatter and varieties with the rolling lines condition. Actual values of these parameters were determined in the archives of the Mobarakeh two stand cold rolling mills and collected on the 210 case study of real chattering. To simulate the experiment, a neural network is trained and weights and bias values of the neural network with genetic optimization algorithm were used to get an optimal neural network which reduces bugs on the test data. So this model is capable to predict speed of Chatter threshold on rolling process of two stand cold rolling mill with the accuracy less than one percent. So it can be used in rolling process with the building intelligent recognition systems to prevent the creator conditions of the chatter frequency range.

  10. 开发中的冷弯成形新技术%New technology development of cold roll forming

    Institute of Scientific and Technical Information of China (English)

    晏培杰; 韩静涛; 王会凤

    2012-01-01

    Due to the advantages of low cost and the products with complex cross section, roll-formed parts are widely used in the automotive, furniture, construction and other industries. In recent years, automotive industries are interested in enhancing the lightweight and safety of parts, roll forming process is logical process to be improved as unique advantage of high efficiency and high material utilization. Five advanced roll forming processes were introduced including 3D roll forming, linear flow splitting, tailor roll forming, partially heated roll forming and hot roll forming. The characteristics of gradually forming in roll forming process are used in the former three technologies, which enrich the section shape of cold roll-formed parts, break out the inherent in the concept of roll forming, such as the uniform thickness and the uniform section. The remaining two new roll forming processes directly change the traditional concept that forming at room temperature, expand the application range of high-strength steel in roll forming process.%冷弯成形具有成本低、可加工复杂截面的型材等优点,所成形的冷弯件在汽车、家具和建筑等领域的应用逐年增长.近年来,随着汽车行业对工件轻量化和安全性要求的不断提高,具有独特的高生产效率、高成材率优点的改进冷弯成形新工艺应运而生.本文主要介绍了最新研究的5种冷弯成形工艺,包括三维成形技术、非等厚辊弯成形技术、分枝辊弯成形技术、局部加热成形技术、热辊弯成形技术.前3种新冷弯成形工艺充分利用冷弯成形中逐道次成形的工艺特点,丰富了冷弯件的截面形状,打破了冷弯件的等截面、等厚度的固有概念.剩下两种新冷弯成形工艺直接改变了冷弯成形工艺在常温下成形的传统概念,使高强钢材料在冷弯成形工艺中应用范围扩大.

  11. Martensite reversion and texture formation in 17Mn-0.06C TRIP/TWIP steel after hot cold rolling and annealing

    Directory of Open Access Journals (Sweden)

    Diana Pérez Escobar

    2015-04-01

    Full Text Available High Mn steels with Si and Al present great plasticity when deformed due to the TRIP/TWIP effect. This work evaluated the microstructural evolution and texture formation of a 17Mn-0.06C steel after hot rolling, cold rolling to 45% of thickness reduction and annealing at 700 °C for different times. The microstructural analysis was performed by means of dilatometry, X-ray diffraction (XRD, optical (OM and scanning electron microscopy (SEM, electron backscattering diffraction EBSD and transmission electron microscopy (TEM. It was found that during the cooling process, after the steel is annealed, the athermal ɛ and α′ martensites are formed. Tensile test results showed that the steel exhibits yield and tensile strength around 650 and 950 MPa with a total elongation around 45%. The austenite texture contains brass, copper and Goss components while the α′ and ɛ martensites textures contain rotated cube and prismatic and pyramidal fibers, respectively.

  12. Characterization on carbide of a novel steel for cold work roll during solidification process

    Energy Technology Data Exchange (ETDEWEB)

    Guo, J.; Liu, L.G.; Li, Q.; Sun, Y.L. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Gao, Y.K. [Institute of Aeronautical Materials, Beijing 100095 (China); Ren, X.J. [School of Engineering, Liverpool John Moores University, Liverpool L3 3AF (United Kingdom); Yang, Q.X., E-mail: qxyang@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

    2013-05-15

    A novel steel for cold work roll was developed in this work. Its phase structures were determined by X-ray diffraction, and phase transformation temperatures during the cooling process were measured by Differential Scanning Calorimeter. The Fe–C isopleths of the steel were calculated by Thermo-Calc to preliminarily determine the characteristic temperatures of the different phases. Then the specimens were quenched at these characteristic temperatures. The typical microstructures were observed by Optical Microscopy and Field Emission Scanning Electron Microscopy with Energy Disperse Spectroscopy. The results show that α-Fe, MC, M{sub 2}C and M{sub 7}C{sub 3} precipitate when the specimen is cooled slowly to room temperature. According to the DSC curve and the Fe–C isopleths, the characteristic temperatures of the phase transformation and carbide precipitation are chosen as 1380 °C, 1240 °C, 1200 °C and 1150 °C respectively. Primary austenite precipitates at 1380 °C, then eutectic reaction occurs in residual liquid after quenching and the eutectic microstructures distribute along the crystal grain boundary. The eutectic MC is leaf-like and eutectic M{sub 2}C is fibrous-like. Both of them precipitate in ternary eutectic reaction simultaneously at 1240 °C, grow together in the form of dendrite along the crystal grain boundary. Secondary MC precipitates from the austenitic matrix at 1200 °C and nucleates at the position where eutectic MC located accompanied by the dissolving of eutectic carbides. The mixed secondary M{sub 2}C and M{sub 7}C{sub 3} precipitate at 1150 °C. The secondary M{sub 2}C is strip-like and honeycomb-like, while the M{sub 7}C{sub 3} is chrysanthemum-like and maze-like. - Highlights: • The solidification process was analyzed by Thermo-Calc, DSC, XRD and SEM observation. • Primary and secondary carbides precipitated during solidification were determined. • The three dimensional morphologies of all carbides was observed. • The

  13. Thermodynamic, adsorption and corrosion inhibitive behaviour of benzyl nicotinate on cold rolled steel in sulphuric acid solution

    Directory of Open Access Journals (Sweden)

    Vinutha Rangaswamy Mutugadahalli

    2015-12-01

    Full Text Available The inhibition performance of benzyl nicotinate (BN on corrosion of cold rolled steel (CRS in 0.5 M H2SO4 solution has been investigated using weight loss, Tafel polarization and electrochemical impedance spectroscopy (EIS. The BN acts as mixed type inhibitor. The thermodynamic parameters indicate the comprehensive nature adsorption of BN on CRS which obey Langmuir isotherm. Morphological investigation of corrosion inhibition is carried out using AFM and optical microscopic studies support the formation of inhibitor film on CRS. There is a good agreement between the values of weight loss measurements and electrochemical studies. 

  14. Nanostructured MgH2 Obtained by Cold Rolling Combined with Short-time High-energy Ball Milling

    OpenAIRE

    Ricardo Floriano; Daniel Rodrigo Leiva; Stefano Deledda; Bjørn Christian Hauback; Walter José Botta

    2013-01-01

    MgH2 was processed by short time high-energy ball milling (BM) and cold rolling (CR). A new alternative processing route (CR + BM) using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process) resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear depen...

  15. COMPLEX OF EQUIPMENT FOR PRODUCTION OF COLD-ROLLED STRIP OF PRECISION ALLOYS

    Directory of Open Access Journals (Sweden)

    A. A. Gorlova

    2011-01-01

    Full Text Available The complex of equipment on production of precision alloys, which will enable to create new and to improve existing technological processes due to rolling of big branded assortment of production, is considered.

  16. Microstructure, Mechanical Properties, and Texture Evolution of Aluminum Alloy 7005 by Accumulative Roll Bonding

    Science.gov (United States)

    Xie, Hu; Wang, M. P.; Chen, Wei; Jia, Yanlin

    2016-03-01

    In the present work, the accumulative roll bonding process was carried out on a 7005 aluminum alloy sheet to six passes. The microstructure and texture evolution was investigated by transmission electron microscope, electron backscatter diffraction analysis, and x-ray texture goniometer. With the increase of ARB passes, the microstructure was refined and the fraction of high angle boundaries increased. The hardness of different ARB process specimens was measured and showed that as the ARB passes increased, the hardness rose obviously. The tensile strength of 6 passes reaches 423.4 MPa and the elongation is 4.6%. The material is strongly textured where individual layers possess typical FCC rolling texture components and the variation of each texture is different. This is attributed to the microstructure evolution during the ARB process.

  17. Effects of texture on the damping characteristics of cold-rolled and annealed Ti50Ni40Cu10 shape memory alloy

    Directory of Open Access Journals (Sweden)

    S. H. Chang

    2015-10-01

    Full Text Available Cold-rolled and annealed Ti50Ni40Cu10 shape memory alloy possesses a major (110[001] texture along the rolling direction and a minor {111} γ-fiber texture along the normal direction. The damping capacity of the B2→B19 and B19→B2 martensitic transformation internal friction peaks for the Ti50Ni40Cu10 shape memory alloy was more pronounced in the rolling direction than in the transverse direction due to the effects of the cold-rolled and annealed textures. The damping capacity of the B19→B19’ and B19’→B19 martensitic transformation internal friction peaks was not noticeable affected by the orientation of the specimen.

  18. Modeling of the Recrystallization and Austenite Formation Overlapping in Cold-Rolled Dual-Phase Steels During Intercritical Treatments

    Science.gov (United States)

    Ollat, M.; Massardier, V.; Fabregue, D.; Buscarlet, E.; Keovilay, F.; Perez, M.

    2017-07-01

    Austenite formation kinetics of a DP1000 steel was investigated from a ferrite-pearlite microstructure (either fully recrystallized or cold-rolled) during typical industrial annealing cycles by means of dilatometry and optical microscopy after interrupted heat treatments. A marked acceleration of the kinetics was found when deformed ferrite grains were present in the microstructure just before austenite formation. After having described the austenite formation kinetics without recrystallization and the recrystallization kinetics of the steel without austenite formation by simple JMAK laws, a mixture law was used to analyze the kinetics of the cold-rolled steel for which austenite formation and recrystallization may occur simultaneously. In the case where the interaction between these two phenomena is strong, three main points were highlighted: (i) the heating rate greatly influences the austenite formation kinetics, as it affects the degree of recrystallization at the austenite start temperature; (ii) recrystallization inhibition above a critical austenite fraction accelerates the austenite formation kinetics; (iii) the austenite fractions obtained after a 1 hour holding deviate from the local equilibrium fractions given by Thermo-Calc, contrary to the case of the recrystallized steel. This latter result could be due to the fact that the dislocations of the deformed ferrite matrix could promote the diffusion of the alloying elements of the steel and accelerate austenite formation.

  19. Accelerated carbonation using municipal solid waste incinerator bottom ash and cold-rolling wastewater: Performance evaluation and reaction kinetics.

    Science.gov (United States)

    Chang, E-E; Pan, Shu-Yuan; Yang, Liuhanzi; Chen, Yi-Hung; Kim, Hyunook; Chiang, Pen-Chi

    2015-09-01

    Accelerated carbonation of alkaline wastes including municipal solid waste incinerator bottom ash (MSWI-BA) and the cold-rolling wastewater (CRW) was investigated for carbon dioxide (CO2) fixation under different operating conditions, i.e., reaction time, CO2 concentration, liquid-to-solid ratio, particle size, and CO2 flow rate. The MSWI-BA before and after carbonation process were analyzed by the thermogravimetry and differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy. The MSWI-BA exhibits a high carbonation conversion of 90.7%, corresponding to a CO2 fixation capacity of 102g perkg of ash. Meanwhile, the carbonation kinetics was evaluated by the shrinking core model. In addition, the effect of different operating parameters on carbonation conversion of MSWI-BA was statistically evaluated by response surface methodology (RSM) using experimental data to predict the maximum carbonation conversion. Furthermore, the amount of CO2 reduction and energy consumption for operating the proposed process in refuse incinerator were estimated. Capsule abstract: CO2 fixation process by alkaline wastes including bottom ash and cold-rolling wastewater was developed, which should be a viable method due to high conversion.

  20. Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling

    Directory of Open Access Journals (Sweden)

    Ricardo Floriano

    2012-01-01

    Full Text Available MgH2 was processed by short time high-energy ball milling (BM and cold rolling (CR. A new alternative processing route (CR + BM using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear dependence between the size/shape of the particles which compose the starting material and the efficiency of crystallite size reduction during the BM process. On the other hand, we observed that a short BM step improved the kinetic properties of the cold rolled material. It shows that the particle size reduction of MgH2 obtained by CR combined with the increase in specific surface area attained by short BM step could be key factors to allow the use of the CR + BM route.

  1. Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling

    Directory of Open Access Journals (Sweden)

    Ricardo Floriano

    2013-02-01

    Full Text Available MgH2 was processed by short time high-energy ball milling (BM and cold rolling (CR. A new alternative processing route (CR + BM using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear dependence between the size/shape of the particles which compose the starting material and the efficiency of crystallite size reduction during the BM process. On the other hand, we observed that a short BM step improved the kinetic properties of the cold rolled material. It shows that the particle size reduction of MgH2 obtained by CR combined with the increase in specific surface area attained by short BM step could be key factors to allow the use of the CR + BM route.

  2. A Discussion on Evolution of Microstructures and Influence Factors during Continuous Rolling of Compact Strip Production

    Institute of Scientific and Technical Information of China (English)

    Hongbo DONG; Yonglin KANG; Hao YU

    2004-01-01

    The evolution of microsturctures and influence factors of ultrathin hot strips of low carbon steel produced by compact strip production (CSP) techniques were investigated. The steel blocking samples of CSP six-passes were obtained, and microstructures at the different positions of workpiece for each pass were studied. At the same time, an explicit finite element technique was used to reveal the continuous rolling process. By combining experiment results with simulation analysis, the effects of plastic strain, temperature, precipitation and interval time on evolution and refinement of crystal grains have been investigated. The results are useful for the development of high strength hot strips.

  3. Cladding of aluminum on AISI 304L stainless steel by cold roll bonding: Mechanism, microstructure, and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Akramifard, H.R., E-mail: akrami.1367@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Mirzadeh, H., E-mail: hmirzadeh@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Advanced Metalforming and Thermomechanical Processing Laboratory, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Parsa, M.H., E-mail: mhparsa@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Center of Excellence for High Performance Materials, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Advanced Metalforming and Thermomechanical Processing Laboratory, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2014-09-08

    The AA1050 aluminum alloy and AISI 304L stainless steel sheets were stacked together to fabricate Al/304L/Al clad sheet composites by the cold roll bonding process, which was performed at temperatures of ∼100 and 23 °C to produce austenitic and austenitic–martensitic microstructures in the AISI 304L counterpart, respectively. The peel test results showed that the threshold reduction required to make a suitable bond at room temperature is below 10%, which is significantly lower than the required reduction for cold roll bonding of Al sheets. The tearing of the Al sheet during the peel test signified that the bond strength of the roll bonded sheets by only 38% reduction has reached the strength of Al, which is a key advantage of the developed sheets. The extrusion of Al through the surface cracks and settling inside the 304L surface valleys due to strong affinity between Al and Fe was found to be the bonding mechanism. Subsequently, the interface and tensile behaviors of three-layered clad sheets after soaking at 200–600 °C for 1 h were investigated to characterize the effect of annealing treatment on the formation and thickening of intermetallic compound layer and the resultant mechanical properties. Field emission scanning electron microscopy, X-ray diffraction, and optical microscopy techniques revealed that an intermediate layer composed mainly of Al{sub 13}Fe{sub 4}, FeC and Al{sub 8}SiC{sub 7} forms during annealing at 500–600 °C. A significant drop in tensile stress–strain curves after the maximum point (UTS) was correlated to the interface debonding. It was found that the formation of intermediate layer by post heat treatment deteriorates the bond quality and encourages the debonding process. Moreover, the existence of strain-induced martensite in clad sheets was found to play a key role in the enhancement of tensile strength.

  4. Effect of ethylenediamine tetraacetic acid disodium on the corrosion of cold rolled steel in the presence of benzotriazole in hydrochloric acid

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Qing [Department of Chemistry, Yunnan University, Kunming 650091 (China)]. E-mail: quqing58@yahoo.com.cn; Jiang, Shuan [Department of Chemistry, Yunnan University, Kunming 650091 (China); Bai, Wei [Department of Chemistry, Yunnan Nationalities University, Kunming 650092 (China); Li, Lei [Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming 650091 (China)

    2007-08-01

    The inhibition behavior of cold rolled steel in 0.1 M hydrochloric acid (HCl) by ethylenediamine tetraacetic acid disodium (EDTA) in the absence and presence of benzotriazole (BTA) was investigated with Tafel polarization curve and electrochemical impedance spectroscopy (EIS). The polarization curve results show that the single EDTA acts as an anodic type inhibitor while the combination of EDTA and BTA acts as mixed type inhibitor and mainly inhibits anodic reaction. All impedance spectra in EIS tests exhibit one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process. Inhibition efficiencies obtained from Tafel polarization, charge transfer resistance (R {sub t}) are consistent. The corrosion of cold rolled steel in 0.1 M HCl is obviously reduced by EDTA in combination with lower concentrations of BTA. Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) were used to characterize the corrosion surface of cold rolled steel. Probable mechanisms are present to explain the experimental results.

  5. Effect of heat treatment on mechanical properties of heavily cold-rolled Fe-6.5wt%Si alloy sheet

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Fe-6.5wt%Si alloy has excellent soft magnetic properties,but it is hard to be cold-rolled due to appearance of ordered phases in this alloy.In this paper we report that ultra thin Fe-6.5wt%Si sheet of 0.05 mm thick was obtained by heavily cold rolling.By means of optical microscope,micro-hardness indenter,instron,SEM and X-ray diffraction,the effect of heat treatment on mechanical properties of this alloy sheet was investigated.The heavily cold-rolled sheet exhibits some extent of ductility.The ultimate tensile strength reaches 1.93 GPa.After heat treatment,micro-hardness is decreased and the ductility is lost,especially at temperature above 650℃ when recrystallization takes place.The reason for decreasing the ductility lies in the ordered DO3 phase transformation.

  6. Jet evolution in hot and cold QCD matter

    Energy Technology Data Exchange (ETDEWEB)

    Domdey, Svend Oliver

    2010-07-23

    In this thesis, we study the evolution of energetic partons in hot and cold QCD matter. In both cases, interactions with the medium lead to energy loss of the parton and its transverse momentum broadens. The propagation of partons in cold nuclear matter can be investigated experimentally in deep-inelastic scattering (DIS) on nuclei. We use the dipole model to calculate transverse momentum broadening in DIS on nuclei and compare to experimental data from HERMES. In hot matter, the evolution of the parton shower is strongly modified. To calculate this modification, we construct an additional scattering term in the QCD evolution equations which accounts for scattering of partons in the quark-gluon plasma. With this scattering term, we compute the modified gluon distribution in the shower at small momentum fractions. Furthermore, we calculate the modified fragmentation function of gluons into pions. The scattering term causes energy loss of the parton shower which leads to a suppression of hadrons with large transverse momentum. In the third part of this thesis, we study double dijet production in hadron collisions. This process contains information about the transverse parton distribution of hadrons. As main result, we find that double dijet production will allow for a study of the transverse growth of hadronic wave functions at the LHC. (orig.)

  7. Modeling texture development during cold rolling of IF steel by crystal plasticity finite element method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    With the consideration of slip deformation mechanism and various slip systems of body centered cubic (BCC) metals,Taylor-type and finite element polycrystai models were embedded into the commercial finite element code ABAQUS to realize crystal plasticity finte element modeling,based on the rate dependent crystal constitutive equations.Initial orientations measured by electron backscatter diffraction (EBSD) were directly input into the crystal plasticity finite element model to simulate the development of rolling texture of interstitial-flee steel (IF steel) at various reductions.The modeled results show a good agreement with the experimental results.With increasing reduction,the predicted and experimental rolling textures tend to sharper,and the results simulated by the Taylor-type model are stronger than those simulated by finite element model.Conclusions are obtained that rolling textures calculated with 48 {110}+{ 112}+{123} slip systems are more approximate to EBSD results.

  8. Influence of cold rolling and annealing on the microstructure, mechanical properties, and electrical conductivity of an artificial microcomposite Cu-18% Nb alloy

    Science.gov (United States)

    Kuznetsov, A. V.; Stepanov, N. D.; Salishchev, G. A.; Pantsyrnyi, V. I.; Khlebova, N. E.

    2010-11-01

    The influence of cold rolling and subsequent annealing at different temperatures on the micro-structure, strength properties, and electrical conductivity of a microcomposite Cu-18% Nb alloy fabricated by bundling and deformation is studied. A composite billet is rolled up to a total true strain of 3.5 and 5.1. After rolling, a nanocrystalline structure is obtained with an average filament width of 70-100 nm depending on the rolling strain. The ultimate tensile strength of the rolled foils is 867-934 MPa and the electrical conductivity is 19-40% of the pure copper conductivity. It is shown that annealing at 550°C results in an increase in the conductivity from 40 to 60% at a retained strength (microhardness) of the alloy.

  9. Rietveld and impedance analysis of cold and hot rolled duplex and lean duplex steels for application in paper and pulp industry

    Energy Technology Data Exchange (ETDEWEB)

    Esteves, Luiza; Lins, Vanessa de Freitas Cunha, E-mail: luizaeq@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Quimica; Paiva, Paulo Renato Perdigao [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET), Belo Horizonte, MG (Brazil); Viana, Adolfo Kalergis do Nascimento [APERAM South America, Timoteo, MG (Brazil)

    2017-01-15

    In this study, X-Ray Diffraction (XRD) and Rietveld Refinement were performed to identify and quantify the ferrite and austenite phase of cold and hot rolled duplex stainless steels (UNS S31803) and lean duplex stainless steels (UNS S32304). Electrochemical impedance spectroscopy (EIS) was applied to evaluate the chemical behavior of duplex and lean duplex stainless steels in white, green, and black liquors of paper and pulp industry. Rietveld analysis results showed a higher austenite content than the standard limit for duplex steels in the hot rolled condition. The hot rolling condition plays a major role in improving corrosion resistance in white liquor mainly for the lean duplex steel. (author)

  10. Product defect compensation by robust optimization of a cold roll forming process

    NARCIS (Netherlands)

    Wiebenga, J.H.; Weiss, M.; Rolfe, B.; Boogaard, van den A.H.

    2013-01-01

    The quality of roll formed products is known to be highly dependent on the process design. In addition, unavoidable variations of material properties during mass production can have a significant deteriorating effect on the product quality. This study focuses on the question how to compensate for pr

  11. The evolution of strain path in cold wire drawing

    Science.gov (United States)

    Zhao, Tianzhang; Zhang, Guang-Liang; Zhang, Shi-Hong; Cheng, Ming; Song, Hong-Wu

    2013-05-01

    Evidence shows that the strain path significantly influences the subsequent material mechanical behaviors, while the strain path effect is neglected in the classical material models. In order to study the influence of strain path on wire property and establish a more accurate material model that will take strain path effects into consideration for improving drawn-wire production, the evolution of strain path must be investigated in cold wire drawing. In this article, three typical models for the expression of strain path change (SPC), which are written by strain rate, strain and stress deviator, respectively, are discussed. Mechanisms of strain path evolution in wire drawing, and the effect of die angle and reduction rate on SPC are investigated via finite element modeling.

  12. Influence of cold rolling direction on texture, inhibitor and magnetic properties in strip-cast grain-oriented 3% silicon steel

    Science.gov (United States)

    Fang, F.; Lu, X.; Zhang, Y. X.; Wang, Y.; Jiao, H. T.; Cao, G. M.; Yuan, G.; Xu, Y. B.; Misra, R. D. K.; Wang, G. D.

    2017-02-01

    An unconventional cold rolling scheme (inclined rolling at 0°, 30°, 45°, 90° during second-stage cold rolling process) was adopted to process grain-oriented silicon steel based on strip casting process. The influences of inclination angles on microstructure, texture, inhibitor and magnetic properties were studied by a combination of EBSD, XRD and TEM. It was found that the α-fiber texture was weakened and γ-fiber was strengthened in cold rolled sheet with increase in inclination angle. The primary recrystallization sheet exhibited more homogeneous microstructure with relatively strong γ-fiber, medium α-fiber texture, weak λ-fiber texture and Goss component at high inclination angles. Fine and homogeneous inhibitors were obtained after primary annealing with increase in inclination angle from 0° to 90° because of more uniform deformation after inclined rolling. The grain-oriented silicon steel experienced completely secondary recrystallization at various inclination angles after final annealing process, with superior magnetic properties at 0° and 90°. Furthermore, Goss nuclei capable of final secondary recrystallization in strip casting process newly formed both in-grain shear bands and grain boundaries region during second-stage cold rolling and subsequent annealing process, which is different from the well-accepted results that Goss texture originated from the subsurface layer of the hot rolled sheet or during intermediate annealing process. In addition, the Goss texture that nucleated in-grain shear bands was weaker but more accurate as compared to that in grain boundaries region.

  13. Forming a perfect cubic texture in thin copper-yttrium alloy strips during cold rolling and annealing

    Science.gov (United States)

    Schastlivtsev, V. M.; Rodionov, D. P.; Khlebnikova, Yu. V.; Akshentsev, Yu. N.; Egorova, L. Yu.; Suaridze, T. R.

    2016-03-01

    The structure of strips produced from the Cu-1 wt % Y binary alloy using cold deformation by rolling to the degree of deformation of 99%, followed by recrystallization annealing, as well as the process of texture formation in these strips, is studied. The possibility of forming a perfect cubic texture in a thin strip made of a binary yttrium-modified copper-based alloy has been shown in principle, which opens the prospect of the use of this alloy to produce substrates for strip high-temperature superconductors of the second generation. The optimum conditions of annealing have been determined, which make it possible to form a perfect biaxial texture in the Cu-1 wt % Y alloy with a content of cubic grains {001} ± 10° on the surface of the textured strip of over 95%.

  14. Nucleation of Cold Rolled FeCo Alloy during Annealing and Its Influence on the Formation of Recrystallization Texture

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The orientation distribution of recrystallization grains formed during annealing, as well as their misorientation relationship to the deformation matrix in cold rolled FeCo alloy have been investigated. It was found that most of the recrystallization nuclei were located near the boundary area with rather random orientations, and their misorientation angles to the deformation matrix were generally very high. However a few nuclei were also observed inside the deformation grains, to which they had very similar orientations. Therefore the misorientation angles between the nuclei and the deformation matrix were generally very low. The orientation and the misorientation distributions of the nuclei have very strong influence on the recrystallization process which could result in a very weak recrystallization texture. The corresponding mechanism is discussed.

  15. MENDED GENETIC BP NETWORK AND APPLICATION TO ROLLING FORCE PREDICTION OF 4-STAND TANDEM COLD STRIP MILL

    Institute of Scientific and Technical Information of China (English)

    Zhang Dazhi; Sun Yikang; Wang Yanping; Cai Hengjun

    2004-01-01

    In order to make good use of the ability to approach any function of BP (back propagation) network and overcome its local astringency,and also make good use of the overall search ability of GA (genetic algorithms),a proposal to regulate the network's weights using both GA and BP algorithms is suggested.An integrated network system of MGA (mended genetic algorithms) and BP algorithms has been established.The MGA-BP network's functions consist of optimizing GA performance parameters,the network's structural parameters,performance parameters,and regulating the network's weights using both GA and BP algorithms.Rolling forces of 4-stand tandem cold strip mill are predicted by the MGA-BP network,and good results are obtained.

  16. Studing the Influence of Six Main Industrial Losses on Overall Equipment Effectiveness in Cold Rolling Unit of Mobarakeh Steel Complex

    Directory of Open Access Journals (Sweden)

    seyed Akbar Nilipour Tabatabaei

    2011-03-01

    Full Text Available Overall Equipment Effectiveness (OEE is a key indicator and a basis for evaluating the effectiveness of equipments as well as assessing the effectiveness of the Total Productive Maintenance (TPM system. This indicator together with overall equipment performance can be used in production lines such as steel production. The aim of this article is to study the influence of six main industrial losses on the OEE indicator . For this purpose, the OEE has been calculated in the cold rolling production lines of Mobarakeh Steel Complex the gap between production lines and the global industrial standards has been studied the causes of production system inefficiency has been investigated and the effectiveness of TPM system, equipments' bottlenecks and the influence of the main industry losses on OEE have been studied. The findings imply that the influence of the variation of availability and performance rates on OEE is high, while the influence of the variation of quality rate on OEE is not considerable.

  17. DNN-Based ADNMPC of an Industrial Pickling Cold-Rolled Titanium Process via Field Enhancement Heat Exchange

    Directory of Open Access Journals (Sweden)

    Biao Yang

    2015-01-01

    Full Text Available The dynamic neural network based adaptive direct nonlinear model predictive control is designed to control an industrial microwave heating pickling cold-rolled titanium process. The identifier of the direct adaptive nonlinear model identification and the controller of the adaptive nonlinear model predictive control are designed based on series-parallel dynamic neural network training by RLS algorithm with variable incremental factor, gain, and forgetting factor. These identifier and controller are used to constitute intelligent controller for adjusting the temperature of microwave heating acid. The correctness of the controller structure, the convergence, and feasibility of the control algorithms is tested by system simulation. For a given point tracking, model mismatch simulation results show that the controller can be implemented on the system to track and overcome the mismatch system model. The control model can be achieved to track on pickling solution concentration and temperature of a given reference and overcome the disturbance.

  18. Oil Film Compensation Control of Hydraulic AGC System in Tandem Cold Rolling Mill%冷连轧机液压AGC系统油膜补偿控制

    Institute of Scientific and Technical Information of China (English)

    孙孟辉; 王益群

    2011-01-01

    Since the request to the quality of cold rolling sheet strips is higher, the hydraulic AGC ( Automatic Gauge Control) has become the indispensable means which improves the product precision of cold rolling strips. However, to the tandem cold rolling mill which backup roll adopts the oil film bearing, the thickness of oil film changes with different rolling force and rolling velocity, which influences the exit thickness of strips and brings the thickness deviation. Especially for the tandem cold rolling mill, the accumulative deviation of every stand enlarges more the deviation of steel product. The oil film compensation model, which adapted to the practical control, was regressed from the data measured from production locale, aiming at one 5-stand tandem cold rolling mill as object. The control strategy was brought forward, which adapted to the distributed computer control. All of them were applied in the practical rolling process for compensation of changes in thickness of oil film. The experimental result indicates that length of out-toler-ance and value of out-tolerance between head and tail of steel product are reduced notably.%由于对冷轧薄板质量要求的提高,液压AGC已经成为提高冷轧带钢成品精度必不可少的手段.然而对于支撑辊采用油膜轴承的冷连轧机来说,其轴承油膜厚度随着轧制力和轧制速度的变化而变化,这将影响轧件的轧出厚度,造成厚差.尤其对冷连轧机,各机架的累积误差会使成品带的超差更加严重.以某五机架冷连轧机为研究对象,由生产现场实测数据回归出适合于实际控制的油膜补偿模型,提出适合于分布式计算机控制的控制策略,并将其应用于实际轧制过程中对油膜厚度变化进行补偿.实验结果表明:加入油膜补偿控制后,成品带钢厚差带头带尾超差段有较为显著的减少,且超差值也有所降低.

  19. Corrosion and Wear Properties of Cold Rolled 0.087% Gd Lean Duplex Stainless Steels for Neutron Absorbing Material

    Directory of Open Access Journals (Sweden)

    Yong Choi

    2016-02-01

    Full Text Available Lean duplex stainless steels with 0.087 wt.% gadolinium (Gd were inert arc-melted and cast in molds of size 10 mm × 10 mm × 20 mm. The micro-hardnesses of the rolling direction (RD, transverse direction (TD and short transverse (ST direction were 258.5 HV, 292.3 HV, and 314.7 HV, respectively. A 33% cold rolled specimen had the crystallographic texture that (100 pole was mainly concentrated to the normal direction (ND and (110 pole was concentrated in the center of ND and RD. The corrosion potential and corrosion rate in artificial seawater and 0.1M H2SO4 solution were in the range of 105.6–221.6 mVSHE, 0.59–1.06 mA/cm2, and 4.75–8.25 mVSHE, 0.69–1.68 mA/cm2, respectively. The friction coefficient and wear loss of the 0.087 w/o Gd-lean duplex stainless steels in artificial seawater were about 67% and 65% lower than in air, whereas the wear efficiency was 22% higher. The corrosion and wear behaviors of the 0.087 w/o Gd-lean duplex stainless steels significantly depended on the Gd phases.

  20. Accelerated carbonation using municipal solid waste incinerator bottom ash and cold-rolling wastewater: Performance evaluation and reaction kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Chang, E-E [Department of Biochemistry, Taipei Medical University, 250 Wu-Hsing Street, Taipei City, Taiwan 110, Taiwan, ROC (China); Pan, Shu-Yuan [Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei City, Taiwan 10673, Taiwan, ROC (China); Yang, Liuhanzi [School of Environment, Tsinghua University, Haidin District, Beijing 100084 (China); Chen, Yi-Hung [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei City, Taiwan 10608, Taiwan, ROC (China); Kim, Hyunook [Department of Energy and Environmental System Engineering, University of Seoul (Korea, Republic of); Chiang, Pen-Chi, E-mail: pcchiang@ntu.edu.tw [Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei City, Taiwan 10673, Taiwan, ROC (China)

    2015-09-15

    Highlights: • Carbonation was performed using CO{sub 2}, wastewater and bottom ash in a slurry reactor. • A maximum capture capacity of 102 g CO{sub 2} per kg BA was achieved at mild conditions. • A maximum carbonation conversion of MSWI-BA was predicted to be 95% by RSM. • The CO{sub 2} emission from Bali incinerator could be expected to reduce by 6480 ton/y. • The process energy consumption per ton CO{sub 2} captured was estimated to be 180 kW h. - Abstract: Accelerated carbonation of alkaline wastes including municipal solid waste incinerator bottom ash (MSWI-BA) and the cold-rolling wastewater (CRW) was investigated for carbon dioxide (CO{sub 2}) fixation under different operating conditions, i.e., reaction time, CO{sub 2} concentration, liquid-to-solid ratio, particle size, and CO{sub 2} flow rate. The MSWI-BA before and after carbonation process were analyzed by the thermogravimetry and differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy. The MSWI-BA exhibits a high carbonation conversion of 90.7%, corresponding to a CO{sub 2} fixation capacity of 102 g per kg of ash. Meanwhile, the carbonation kinetics was evaluated by the shrinking core model. In addition, the effect of different operating parameters on carbonation conversion of MSWI-BA was statistically evaluated by response surface methodology (RSM) using experimental data to predict the maximum carbonation conversion. Furthermore, the amount of CO{sub 2} reduction and energy consumption for operating the proposed process in refuse incinerator were estimated. Capsule abstract: CO{sub 2} fixation process by alkaline wastes including bottom ash and cold-rolling wastewater was developed, which should be a viable method due to high conversion.

  1. Soft magnetism in nitrided Fe93Ni4Cr3 and Fe94Ni4T2 cold-rolled alloys

    NARCIS (Netherlands)

    Craus, CB; Chezan, AR; Chechenin, NG; Boerma, DO; Niesen, L

    2003-01-01

    The magnetic properties in relation with the structure of nitrided cold-rolled Fe93Ni4Cr3 and Fe94Ni4Ti2 were studied. Various low-temperature nitriding treatments were applied in order to obtain soft magnetic materials. We show that the magnetic anisotropy depends sensitively on the nitrogen conten

  2. 磁尺在冷连轧系统中的应用%Application of SONY Magnetic Scale in Cold Tandem Rolling Mill

    Institute of Scientific and Technical Information of China (English)

    张霆

    2013-01-01

      介绍磁尺在某冷连轧机组中作为 AGC 系统的位移传感器的应用方法。%The article describes how SONY Magnetic Scale works as position transducer in the AGC system of a cold tandem rolling mill.

  3. Microstructure evolution in hot rolled 7075 Al via friction stir processing

    Science.gov (United States)

    Guo, Mei Ling; Tan, Ming Jen; Liu, Feng Chao; Song, Xu; Chua, Beng Wah

    2016-10-01

    Friction stir processed (FSP) hot rolled 7075 Al alloy with grain size of 5.2 μm was investigated in the temperature range 350 °C-500 °C and strain rates from 3x10-4 to 10-1 s-1. Maximum superplastic elongation of 776.4 % was achieved at 500 °C and strain rate 10-3 s-1. The microstructure evolution of FSP 7075 Al during superplastic deformation was studied by electron backscatter diffraction (EBSD). Further analyses of superplastic results indicated the main deformation mechanism of FSP 7075 Al was grain boundary sliding (GBS).

  4. Influence of process parameters on the microstructural evolution of a rear axle tube during cross wedge rolling

    Science.gov (United States)

    Ma, Jia-wei; Yang, Cui-ping; Zheng, Zhen-hua; Zhang, Kang-sheng; Ma, Wen-yu

    2016-11-01

    In the shaping process of cross wedge rolling (CWR), metal undergoes a complex microstructural evolution, which affects the quality and mechanical properties of the product. Through secondary development of the DEFORM-3D software, we developed a rigid plastic finite element model for a CWR-processed rear axle tube, coupled with thermomechanical and microstructural aspects of workpieces. Using the developed model, we investigated the microstructural evolution of the CWR process. Also, the influence of numerous parameters, including the initial temperature of workpieces, the roll speed, the forming angle, and the spreading angle, on the grain size and the grain-size uniformity of the rolled workpieces was analyzed. The numerical simulation was verified through rolling and metallographic experiments. Good agreement was obtained between the calculated and experimental results, which demonstrated the reliability of the model constructed in this work.

  5. Annealing Behavior of Nanostructured Aluminum Produced by Cold Rolling to Ultrahigh Strains

    DEFF Research Database (Denmark)

    Cao, W.Q.; Godfrey, A.; Hansen, Niels

    2009-01-01

    200 degrees C to 220 degrees C. This effect is exemplified by samples deformed to the largest strain, where a rapid decrease in the stored energy from approximately 2 MJ/m(3) in the deformed state to less than 0.5 MJ/m(3) is seen, accompanied by a large decrease in the hardness. A new method...... to 420 degrees C. Microstructural and texture measurements were made using data from electron backscatter diffraction (EBSD) investigations, and the change in mechanical strength was followed using hardness measurements. A large effect of the rolling strain is observed on recovery at temperatures below...

  6. The Structure and Evolution of Cold Dark Matter Halos

    Science.gov (United States)

    Diemand, Jürg; Moore, Ben

    2011-02-01

    In the standard cosmological model a mysterious cold dark matter (CDM) component dominates the formation of structures. Numerical studies of the f ormation of CDM halos have produced several robust results that allow unique tests of the hierarchical clustering paradigm. Universal properties of halos, including their mass profiles and substructure properties are roughly consistent with observational data from the scales of dwarf galaxies to galaxy clusters. Resolving the fine grained structure of halos has enabled us to make predictions for ongoing and planned direct and indirect dark matter detection experiments. While simulations of pure CDM halos are now very accurate and in good agreement (recently claimed discrepancies are addressed in detail in this review), we are still unable to make robust, quantitative predictions about galaxy formation and about how the dark matter distribution changes in the process. Whilst discrepancies between observations and simulations have been the subject of much debate in the literature, galaxy formation and evolution needs to be understood in more detail in order to fully test the CDM paradigm. Whatever the true nature of the dark matter particle is, its clustering properties must not be too different from a cold neutralino like particle to maintain all the successes of the model in matching large scale structure data and the global properties of halos which are mostly in good agreement with observations.

  7. Evolution of Cold Streams and Emergence of the Hubble Sequence

    CERN Document Server

    Cen, Renyue

    2014-01-01

    A new physical framework for the emergence of the Hubble sequence is outlined, based on novel analyses performed to quantify the evolution of cold streams of a large sample of galaxies from a state-of-the-art ultra-high resolution, large-scale adaptive mesh-refinement hydrodynamic simulation in a fully cosmological setting. It is found that the following three key physical variables of galactic cold inflows crossing the virial sphere substantially decrease with decreasing redshift: the number of streams N_{90} that make up 90% of concurrent inflow mass flux, average inflow rate per stream dot M_{90} and mean (mass flux weighted) gas density in the streams n_{gas}. Another key variable, the stream dimensionless angular momentum parameter lambda, instead is found to increase with decreasing redshift. Assimilating these trends and others leads naturally to a physically coherent scenario for the emergence of the Hubble sequence, including the following expectations: (1) the predominance of a mixture of disproport...

  8. INCREASING STAMPING FORMABILITY OF LOW-CARBON COLD ROLLED THIN STEEL SHEETS

    Directory of Open Access Journals (Sweden)

    I. Tatarkina

    2015-12-01

    Full Text Available The use of surfactant (épila was studied as a method for improving the cold-formability of steel sheets. The factors of the resulting effect were analyzed. Application of épila significantly reduces the surface roughness and decreases the stress concentrates. Epilam fills pores and microcracks, displaces moisture and gases, thereby reducing metal embrittlement. The application of épila pro-vides the highest category of drawing the low carbon sheet steel 08kp.

  9. Formation and Evolution of Non-dendritic Microstructures of Semisolid Alloys Prepared by Shearing/Cooling Roll Process

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The shearing/cooling roll (SCR) process was adopted to prepare semi-solid A2017 alloy. The formation and evolution of non-dendritic microstructures in semi-solid A2017 alloy were studied. It is shown that the microstructures of semi-solid billets transform from coarse dendrites into fine equiaxed grains as the pouring temperature of molten alloy decreases or roll-shoe cavity height is reduced. From the inlet to the exit of roll-shoe cavity, microstructure of semi-solid slurry near the shoe surface is in the order of coarse dendrites,degenerated dendrites or equiaxed grains, but fine equiaxed grains are near the roll surface. Microstructural evolution of semi-solid slurry prepared by SCR process is that the molten alloy nucleates and grows into dendrite firstly on the roll and shoe's surface. Under the shearing and stirring given by the rotating roll, the dendrites crush off and disperse into the melt. Under the shearing and stirring on semi-solid slurry with high volume fraction of solid, the dendrite arms fracture and form equiaxed grain microstructures.

  10. Evolution of carbides in cold-work tool steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hoyoung [Department of Materials Science and Engineering, Pusan National University, 2 Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Korea Institute of Materials Science, 797 Changwon-daero, Seongsan-gu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Kang, Jun-Yun, E-mail: firice@kims.re.kr [Korea Institute of Materials Science, 797 Changwon-daero, Seongsan-gu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Son, Dongmin [Seah Changwon Special Steel, 147 Jeokhyeon-ro, Seongsan-gu, Changwon, Gyeongnam 642-370 (Korea, Republic of); Lee, Tae-Ho [Korea Institute of Materials Science, 797 Changwon-daero, Seongsan-gu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Cho, Kyung-Mox, E-mail: chokm@pusan.ac.kr [Department of Materials Science and Engineering, Pusan National University, 2 Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of)

    2015-09-15

    This study aimed to present the complete history of carbide evolution in a cold-work tool steel along its full processing route for fabrication and application. A sequence of processes from cast to final hardening heat treatment was conducted on an 8% Cr-steel to reproduce a typical commercial processing route in a small scale. The carbides found at each process step were then identified by electron diffraction with energy dispersive spectroscopy in a scanning or transmission electron microscope. After solidification, MC, M{sub 7}C{sub 3} and M{sub 2}C carbides were identified and the last one dissolved during hot compression at 1180 °C. In a subsequent annealing at 870 °C followed by slow cooling, M{sub 6}C and M{sub 23}C{sub 6} were added, while they were dissolved in the following austenitization at 1030 °C. After the final tempering at 520 °C, fine M{sub 23}C{sub 6} precipitated again, thus the final microstructure was the tempered martensite with MC, M{sub 7}C{sub 3} and M{sub 23}C{sub 6} carbide. The transient M{sub 2}C and M{sub 6}C originated from the segregation of Mo and finally disappeared due to attenuated segregation and the consequent thermodynamic instability. - Highlights: • The full processing route of a cold-work tool steel was simulated in a small scale. • The carbides in the tool steel were identified by chemical–crystallographic analyses. • MC, M{sub 7}C{sub 3}, M{sub 2}C, M{sub 6}C and M{sub 23}C{sub 6} carbides were found during the processing of the steel. • M{sub 2}C and M{sub 6}C finally disappeared due to thermodynamic instability.

  11. Microstructural Features and Mechanical Properties Induced by the Spray Forming and Cold Rolling of the Cu-13.5 wt pct Sn Alloy

    Institute of Scientific and Technical Information of China (English)

    Xiaofeng WANG; Jiuzhou ZHAO; Jie HE; Jiangtao WANG

    2008-01-01

    Copper alloys with high strength and high conductivity are an important functional material with full of potential applications. In the present investigation, a bronze with higher tin content (Cu-13.5 wt pct Sn)was prepared successfully by spray forming, the feasibility of cold rolling this alloy was investigated, and the cold rolling characteristics of this alloy have also been discussed. The results indicate that the spray-formed Cu-13.5 wt pct Sn alloy, compared with the as-cast ingot, shows a quite fine and homogeneous single-phase structure, and, therefore shows an excellent workability. It can be cold-rolled with nearly 15% reduction in the thickness per pass and the total reduction can reach 80%. The classical border between the wrought and cast alloys is shifted to considerably higher tin contents by spray forming. After proper thermo-mechanical treatment, spray-formed Cu-13.5 wt pct Sn alloy exhibits excellent comprehensive mechanical properties.Particularly, it shows a low elastic modulus (~88 GPa) and a high flow stress (over 800 MPa) after cold forming. This combination of properties is unique in the domain of metallic materials and could open new possibilities in spring technology field.

  12. CVC冷轧机承载辊缝凸度调节域计算模型%Model of CVC Cold Rolling Mill Loaded Roll Gap Crown Control Room

    Institute of Scientific and Technical Information of China (English)

    李勇华; 邸洪双; 刘光明; 郝亮

    2011-01-01

    The crown control room prediction model of loaded roll gap of 4-high CVC cold rolling mill was developed.The loaded roll gap was divided into two parts, unloaded roll gap crown and deformation roll gap crown.Taking a CVC mill as an example, the model calculated result was consistent with the result that calculated by influence function method.It could be used to preset the shape crown of different actual production conditions on line.%开发了四辊CVC冷轧机承载辊缝凸度调节域预报模型,其将承载辊缝分为空载辊缝凸度与变形辊缝凸度两部分.以某厂CVC轧机为例,计算的凸度调节域与影响函数法计算的凸度调节域相吻合,可在线对不同工况下的轧机进行板凸度的预设定.

  13. Cold-rolled complex-phase steels: AHSS material with remarkable properties

    Energy Technology Data Exchange (ETDEWEB)

    Hebesberger, T.; Pichler, A.; Walch, C.; Blaimschein, M. [voestalpine Stahl GmbH, Linz (Austria); Spiradek-Hahn, K. [ARC Seibersdorf Research GmbH (Austria)

    2005-07-01

    The reduction of the body-in-white weight, in combination with stiffness and crash safety improvements is of fundamental interest in the automotive industry. Therefore, several Advanced High Strength Steel (AHSS) grades have been developed in the last several years, whereby the main focus was laid on dual-phase (DP) and TRIP steels. Recently, a new high strength steel grade - complex-phase (CP) steels - is gaining more and more interest. In contrast to DP grades of similar strength level, CP grades have a significantly higher yield strength and thus a higher yield ratio. Although, CP grades reach lower elongation values in the tensile test, they show an excellent bendability and stretch-flangeability. Due to this remarkable balance between strength, bendability and stretch-flangeability, complex-phase steels are potential candidates for roll-formed parts and parts where sharp radii and/or a good formability of punched edges are required. Therefore, the microstructure, the processing, and the formability of CP grades are discussed in detail in this work. (orig.)

  14. Effect of cryorolling and warm rolling on precipitation evolution in Al 6061 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Rao, P. Nageswara [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand (India); Viswanadh, B. [Materials Science Division, Bhabha Atomic Research Center, Mumbai 40085, Maharashtra (India); Jayaganthan, R., E-mail: rjayafmt@iitr.ernet.in [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand (India)

    2014-06-01

    In the present investigation, the effect of deformation on precipitation sequence and microstructural evolution in Al 6061 alloy was studied using low temperature differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The precipitation sequence was greatly influenced by deformation in cryorolled and warm rolled samples. At low temperatures (<150 °C), two distinct cluster peaks have been observed upon cryorolling (CR). At high temperatures (>150 °C), the peak corresponding to β′ formation has disappeared in the deformed alloy as compared to undeformed coarse grained material. TEM investigation of the deformed alloy revealed bimodal distribution of precipitate sizes with both very fine and coarse structures. Pre-deformation of the alloy led to the simultaneous formation of β″ and β′ precipitates. Activation energies of clusters and major strengthening phase formation were calculated for the cryorolled and warm rolled materials and compared with the undeformed coarse grained material. The reduction of free energy for the formation of strengthening phase has occurred in the deformed material as compared to undeformed bulk material.

  15. Microstructure and texture evolution during tensile deformation of symmetric/asymmetric-rolled low carbon microalloyed steel

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Minghui, E-mail: minghui.cai@deakin.edu.au [Institute for Frontier Materials (IFM), Deakin University, Geelong VIC 3217 (Australia); Wei, Xing [R & D Centre of Wuhan Iron & Steel (Group) Corp (WISCO), Wuhan 430080 (China); Rolfe, Bernard [Institute for Frontier Materials (IFM), Deakin University, Geelong VIC 3217 (Australia); Hodgson, Peter D., E-mail: minghui.cai@deakin.edu.au [Institute for Frontier Materials (IFM), Deakin University, Geelong VIC 3217 (Australia)

    2015-08-12

    The deformation and fracture mechanisms of a low carbon microalloyed steel processed by asymmetric rolling (AsR) and symmetric rolling (SR) were compared by microstructural and texture evolutions during uniaxial tensile deformation. A realistic microstructure-based micromechanical modeling was involved as well. AsR provides more effective grain refinement and beneficial shear textures, leading to higher ductility and extraordinary strain hardening with improved yield and ultimate tensile stresses as well as promoting the occurrence of ductile fracture. This was verified and further explained by means of the different fracture modes during quasi-static uniaxial deformation, the preferred void nucleation sites and crack propagation behavior, and the change in the dislocation density based on the kernel average misorientation (KAM) distribution. The equivalent strain/stress partitioning during tensile deformation of AsR and SR specimens was modeled based on a two-dimensional (2D) representative volume element (RVE) approach. The trend of strain/stress partitioning in the ferrite matrix agrees well with the experimental results.

  16. Cube texture generation dependence on deformation textures in cold rolled OFE copper

    Energy Technology Data Exchange (ETDEWEB)

    Necker, C.T.; Rollett, A.D. [Los Alamos National Lab., NM (United States); Doherty, R.D. [Drexel Univ., Philadelphia, PA (United States)

    1993-10-01

    The evolution of the {alpha} and {beta} fiber deformation textures in OFE copper for von Mises strains of 1.0 to 4.5 is reported as well as how it affects the generation of cube recrystallization textures. Computational volume fraction analysis of the fibers indicates that the deformation texture evolves evenly along the length of the fibers. Fiber weakening during recrystallization does not occur more selectively in any one component or section of the fiber but occurs relatively evenly across the fiber. Cube grains grow without misorientation preference into the deformed structure. Microtextural analysis of the fully recrystallized samples indicates that the cube component (defined as less than 20{degrees} misorientation from {l_brace}100{r_brace}<001>) not only strengthens with increasing prior strain but also becomes much sharper, more closely aligned with the exact cube position. These results are explained by the evolution of the environment (texture and microstructure) surrounding potential nucleation sites.

  17. The evaluation of surface and adhesive bonding properties for cold rolled steel sheet for automotive treated by Ar/O{sub 2} atmospheric pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chan Joo; Lee, Sang Kon; Kim Byung Min [Pusan National University, Busan (Korea, Republic of); Park, Keun Whan [Sungwoo Hitech Technical Institute, Busan (Korea, Republic of)

    2008-04-15

    Cold rolled steel sheet for automotive was treated by Ar/O{sub 2} atmospheric pressure plasma to improve the adhesive bonding strength. Through the contact angle test and calculation of surface free energy for cold rolled steel sheet, the changes of surface properties were investigated before and after plasma treatment. The contact angle was decreased and surface free energy was increased after plasma treatment. And the change of surface roughness and morphology were observed by AFM(Atomic Force Microscope). The surface roughness of steel sheet was slightly changed. Based on Taguchi method, single lap shear test was performed to investigate the effect of experimental parameter such as plasma power, treatment time and flow rate of O{sub 2} gas. Results shows that the bonding strength of steel sheet treated in Ar/O{sub 2} atmospheric pressure plasma was improved about 20% compared with untreated sheet.

  18. Mechanical properties of Fe -10Ni -7Mn martensitic steel subjected to severe plastic deformation via cold rolling and wire drawing

    Science.gov (United States)

    Ghasemi-Nanesa, H.; Nili-Ahmadabadi, M.; Shirazi, H.

    2010-07-01

    Fe-Ni-Mn martensitic steels are one of the major groups of ultra-high strength steels that have good mechanical properties and ductility in as annealed condition but they suffer from severe inter-granular embitterment after aging. In this paper, the effect of heavy shaped cold rolling and wire drawing on the mechanical properties of Fe-Ni-Mn steel was investigated. This process could provide a large strain deformation in this alloy. The total strain was epsilon ~7. Aging behavior and tensile properties of Fe-10Ni-7Mn were studied after aging at 753 K. The results showed that the ultimate tensile strength and ductility after cold rolling, wire drawing and aging increased up to 2540 MPa and 7.1 %, respectively, while the conventional steels show a premature fracture stress of 830 MPa with about zero ductility after aging.

  19. Mechanical properties of Fe -10Ni -7Mn martensitic steel subjected to severe plastic deformation via cold rolling and wire drawing

    Energy Technology Data Exchange (ETDEWEB)

    Ghasemi-Nanesa, H; Shirazi, H [School of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, P.O. Box 14395-731 (Iran, Islamic Republic of); Nili-Ahmadabadi, M, E-mail: sut.caster.81710018@gmail.co, E-mail: nili@ut.ac.i [School of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, P.O. Box 14395-731 (Iran, Islamic Republic of) and Center of Excellence for High Performance Materials, University of Tehran, P.O. Box 14395-731, Tehran (Iran, Islamic Republic of)

    2010-07-01

    Fe-Ni-Mn martensitic steels are one of the major groups of ultra-high strength steels that have good mechanical properties and ductility in as annealed condition but they suffer from severe inter-granular embitterment after aging. In this paper, the effect of heavy shaped cold rolling and wire drawing on the mechanical properties of Fe-Ni-Mn steel was investigated. This process could provide a large strain deformation in this alloy. The total strain was {epsilon} {approx}7. Aging behavior and tensile properties of Fe-10Ni-7Mn were studied after aging at 753 K. The results showed that the ultimate tensile strength and ductility after cold rolling, wire drawing and aging increased up to 2540 MPa and 7.1 %, respectively, while the conventional steels show a premature fracture stress of 830 MPa with about zero ductility after aging.

  20. Effect of continuous annealing parameters on the mechanical properties and microstructures of a cold rolled dual phase steel

    Institute of Scientific and Technical Information of China (English)

    Shuang Kuang; Yong-lin Kang; Hao Yu; Ren-dong Liu

    2009-01-01

    A cold rolled dual phase (DP) steel with the C-Si-Mn alloy system was trial-produced in the laboratory, utilizing a Glee-ble-3800 thermal simulator. The effects of continuous annealing parameters on the mechanical properties and microstructures of the DP steel were investigated by mechanical testing and microstructure observation. The results show that soaking between 760 and 820 ℃ for more than 80 s, rapid cooling at the rate of more than 30℃/s from the quenching temperature between 620 and 680℃, and overaging lower than 300°C are beneficial for the mechanical properties of DP steels. An appropriate proportion of the two phases is one of the key factors for the favorable properties of DP steels. If the volume fraction of martensite and, thereby, free dislocations are deficient, the tensile strength and n value of DP steels will decrease, whereas, the yield slrength will increase. But if the volume frac-tion of martensite is excessive to make it become a dominant phase, the yield and tensile strength will increase, whereas, the elonga-tion will decrease obviously. When rapid cooling rate is not fast enough, pearlite or cementite will appear, which will degrade the mechanical properties. Even though martensite is sufficient, if it is decomposed in high temperature tempering, the properties will be unsatisfied.

  1. Effect of cold rolling and first precipitates on the coarsening behavior of γ″-phases in Inconel 718 alloy

    Science.gov (United States)

    Zhang, Jing-ling; Guo, Qian-ying; Liu, Yong-chang; Li, Chong; Yu, Li-ming; Li, Hui-jun

    2016-09-01

    The coarsening behaviors of γ″-phase particles in Inconel 718 alloy aged at 750, 800, and 850°C were investigated by scanning electron microscopy (SEM). Detailed observations and quantitative measurements were conducted to characterize the coarsening behavior of the γ?-phase under various aging conditions. The experimental results indicate that the existence of the δ-phase retards the formation and coarsening of the γ″-phase, without influencing its final particle size or amount. Moreover, when cold rolled with a reduction of 50%, the dimensions of the γ″ particles in Inconel 718 alloy decrease with increasing aging time. Furthermore, the coarsening behavior of the γ″-phase in the Inconel 718 alloy after a normal aging treatment (sample A) and that of the primary δ-phase (sample B) follow the Lifshitz-Slyozov-Wagner (LSW) diffusion-controlled growth theory; the thus-obtained activation energies for the γ″-phase are 292 kJ·mol-1 and 302 kJ·mol-1, respectively.

  2. The Influence of Processing Conditions on Microchemistry and the Softening Behavior of Cold Rolled Al-Mn-Fe-Si Alloys

    Directory of Open Access Journals (Sweden)

    Ning Wang

    2016-03-01

    Full Text Available Using different homogenization treatments, different initial microchemistry conditions in terms of solid solution levels of Mn, and number densities and sizes of constituents and dispersoids were achieved in an Al-Mn-Fe-Si model alloy. For each homogenized condition, the microchemistry and microstructure, which further change both during deformation and subsequent annealing, were quantitatively characterized. The influence of the different microchemistries, with special focus on different particle structures (constituents and dispersoids, on the softening behavior during annealing after cold rolling and the final grain structure has been systematically studied. Time-Temperature-Transformation diagrams with respect to precipitation and recrystallization as a basis for analysis of the degree of concurrent precipitation during back-annealing have been established. Densely distributed fine pre-existing dispersoids and/or conditions of significant concurrent precipitation strongly slows down recrystallization kinetics and lead to a grain structure of coarse and strongly elongated grains. At the lowest annealing temperatures, recrystallization may even be completely suppressed. In conditions of low number density and coarse pre-existing dispersoids, and limited additional concurrent precipitation, recrystallization generally results in an even, fine and equi-axed grain structure. Rough calculations of recrystallized grain size, assuming particle stimulated nucleation as the main nucleation mechanism, compare well with experimentally measured grain sizes.

  3. Effect of Chromium on Microstructure and Mechanical Properties of Cold Rolled Hot-dip Galvanizing DP450 Steel

    Institute of Scientific and Technical Information of China (English)

    Yun HAN; Shuang KUANG; Hua-sai LIU; Ying-hua JIANG; Guang-hui LIU

    2015-01-01

    Two cold rolled hot-dip galvanizing dual phase (DP) 450 steels with different amounts of chromium were designed and the effects of the chromium concentration and galvanizing processes on the microstructure and mechanical properties were also investigated. The results show that the experimental steels exhibit typical dual phase microstructure character. However, the ferrite phase of steel with higher chromium is more regular and its boundaries are clearer. Meanwhile, martensite austenite (MA) island in steel No. 2 is diffused and no longer distributes along the grain boundary as net or chain shape. More MA islands enriched with Cr element can be found in the ferrite grains, and the increment of Cr element improves the stablity of the austenite so that the austenite has been reserved in MA islands. In addition, the experimental steel with higher chromium exhibits better elongation, lower yield ratio and better formability. The mean hole expanding ratio of steels No. 1 and No. 2 is 161.70% and 192.70%, respectively.

  4. Effects of Annealing Treatment Prior to Cold Rolling on Delayed Fracture Properties in Ferrite-Austenite Duplex Lightweight Steels

    Science.gov (United States)

    Sohn, Seok Su; Song, Hyejin; Kim, Jung Gi; Kwak, Jai-Hyun; Kim, Hyoung Seop; Lee, Sunghak

    2016-02-01

    Tensile properties of recently developed automotive high-strength steels containing about 10 wt pct of Mn and Al are superior to other conventional steels, but the active commercialization has been postponed because they are often subjected to cracking during formation or to the delayed fracture after formation. Here, the delayed fracture behavior of a ferrite-austenite duplex lightweight steel whose microstructure was modified by a batch annealing treatment at 1023 K (750 °C) prior to cold rolling was examined by HCl immersion tests of cup specimens, and was compared with that of an unmodified steel. After the batch annealing, band structures were almost decomposed as strong textures of {100} α-fibers and {111} γ-fibers were considerably dissolved, while ferrite grains were refined. The steel cup specimen having this modified microstructure was not cracked when immersed in an HCl solution for 18 days, whereas the specimen having unmodified microstructure underwent the delayed fracture within 1 day. This time delayed fracture was more critically affected by difference in deformation characteristics such as martensitic transformation and deformation inhomogeneity induced from concentration of residual stress or plastic strain, rather than the difference in initial microstructures. The present work gives a promise for automotive applications requiring excellent mechanical and delayed fracture properties as well as reduced specific weight.

  5. Effects of overaging temperature on the microstructure and properties of 600 MPa cold-rolled dual-phase steel

    Institute of Scientific and Technical Information of China (English)

    Chun-fu Kuang; Zhi-wang Zheng; Gong-ting Zhang; Jun Chang; Shen-gen Zhang; Bo Liu

    2016-01-01

    C–Mn steels prepared by annealing at 800°C for 120 s and overaging at 250–400°C were subjected to pre-straining (2%) and bak-ing treatments (170°C for 20 min) to measure their bake-hardening (BH2) values. The effects of overaging temperature on the microstructure, mechanical properties, and BH2 behavior of 600 MPa cold-rolled dual-phase (DP) steel were investigated by optical microscopy, scanning electron microscopy, and tensile tests. The results indicated that the martensite morphology exhibited less variation when the DP steel was overaged at 250–350°C. However, when the DP steel was overaged at 400°C, numerous non-martensite and carbide particles formed and yield-point elongation was observed in the tensile curve. When the overaging temperature was increased from 250 to 400°C, the yield strength increased from 272 to 317 MPa, the tensile strength decreased from 643 to 574 MPa, and the elongation increased from 27.8%to 30.6%. Furthermore, with an increase in overaging temperature from 250 to 400°C, the BH2 value initially increases and then decreases. The maximum BH2 value of 83 MPa was observed for the specimen overaged at 350°C.

  6. Microstructure and texture evolution in multi-pass warm rolled AZ31 magnesium alloy

    Directory of Open Access Journals (Sweden)

    Liu Di

    2015-01-01

    Full Text Available Electron Backscatter Diffraction (EBSD is employed to characterize the microstructure and texture established during the process of warm rolled AZ31 magnesium alloy sheets. The grain size was refined from 17.4 μm to 3.8 μm after 4 pass rolling. Texture of as-rolled sheets was expressed by (0002 basal texture, and the texture intensity was increased with the rolling pass increasing. The mechanical properties of as-rolled sheets were greatly improved by warm rolling.

  7. Development of high and medium resistance low alloys steels, cold rolling on USIMINAS; Desenvolvimento de acos de media e alta resistencia, baixa liga laminados a frio na USIMINAS

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Luiz N.T.; Barcelos, Haroldo; Oliveira Junior, Valdomiro de [USIMINAS, Ipatinga, MG (Brazil). Centro de Pesquisas

    1984-12-31

    Results on laboratory and industrial trials to the production of high strength, low alloy, cold rolled steels are presented. The first of them, class 400 MPa tensile strength, containing P and Mn and the other, class 440-500 MPA tensile strength, containing Mn, Si and Nb as alloying elements. The performance of these two materials in the production of automotive industry is also reported. 4 figs., 11 tabs., 12 refs.

  8. Measurements of Residual Stresses in Cold-Rolled 304 Stainless Steel Plates Using X-Ray Diffraction with Rietveld Refinement Method

    Directory of Open Access Journals (Sweden)

    Parikin

    2015-10-01

    Full Text Available The determination of the residual stresses using X-ray powder diffraction in a series of cold-rolled 304 stainless steel plates, deforming 0, 34, 84, 152, 158, 175 and 196 % reduction in thickness has been carried out. The diffraction data were analyzed using the Rietveld structure refinement method. The analysis shows that for all specimens, the martensite particles are closely in compression and the austenite matrix is in tension. Both the martensite and austenite, for a sample reducing 34% in thickness (containing of about 1% martensite phase the average lattice strains are anisotropic and decrease approximately exponential with an increase in the corresponding percent reduction (essentially phase content. It is shown that this feature can be qualitatively understood by taking into consideration the thermal expansion mismatch between the martensite and austenite grains. Also, for all cold-rolled stainless steel specimens, the diffraction peaks are broader than the unrolled one (instrumental resolution, indicating that the strains in these specimens are inhomogeneous. From an analysis of the refined peak shape parameters, the average root-mean square strain, which describes the distribution of the inhomogeneous strain field, was predicted. The average residual stresses in cold-rolled 304 stainless steel plates showed a combination effect of hydrostatic stresses of the martensite particles and the austenite matrix.

  9. Decoupling control based on terminal sliding mode and wavelet network for the speed and tension system of reversible cold strip rolling mill

    Science.gov (United States)

    Fang, Yiming; Liu, Le; Li, Jianxiong; Xu, Yanze

    2015-08-01

    To weaken the nonlinear coupling influences among the variables in the speed and tension system of reversible cold strip rolling mill, a novel dynamic decoupling control strategy is proposed based on nonsingular fast terminal sliding mode (NFTSM) and wavelet neural network (WNN). First, nonlinear disturbance observers are developed to counteract the mismatched uncertainties, and then input/output dynamic decoupling and linearisation for the speed and tension nonlinear coupling system are realised by utilising the inverse system theory. Second, nonsingular fast terminal sliding mode controller (NFTSMC) for each pseudo linear subsystem is presented based on backstepping and two-power reaching law, so as to improve the global convergence speed and robust stability of the system. Third, adaptive WNNs are used to approximate the uncertain items of the system, so as to improve the control precision of the speed and tension of reversible cold strip rolling mill. Theoretical analyses show that the NFTSMs satisfy reachability condition, the system error variables can converge to equilibrium point in finite time, and the resulting closed-loop system is globally asymptotically stable. Finally, simulation research is carried out on the speed and tension system of a 1422 mm reversible cold strip rolling mill by using the actual data, and results show the superiority of the proposed control strategy in comparison with the strategies of cascade PI, linear sliding mode control and internal model control.

  10. Application and Development of Simulation Technology in Cold Continuous Rolling Mill%仿真技术在冷连轧系统的应用及发展

    Institute of Scientific and Technical Information of China (English)

    崔建江; 吴胜昔; 袁枫华; 徐心和

    2001-01-01

    This paper analyses a dynamic simulation system of cold rolling mill and discusses the status and signification of simulation application and development of cold rolling mill in our country and foreign countries. Modeling and process of simulation in cold rolling mill are analysed. The execution of dynamic simulation includes the advanced modelling technology and time coordination scheduling and the use of multi-advanced simulation technology, such as coordernation simulation, simulation database, and integrated simulation. In this field virtual reality and intelligent simulation maybe act as future development in the end.%分析了一类冷连轧动态仿真系统,综述了仿真技术在冷连轧中在国内外的应用发展现状、以及发展冷连轧动态系统的意义。分析了仿真动态系统的建模及实现过程,冷连轧动态仿真的实施包含先进的模型化技术及时间协调调度,多种先进仿真技术的使用如协调仿真、仿真数据库技术一体化仿真。最后展望了该领域在虚拟现实和智能仿真技术的今后发展方向。

  11. Austenite formation during intercritical annealing in C-Mn cold-rolled dual phase steel

    Institute of Scientific and Technical Information of China (English)

    李声慈; 康永林; 朱国明; 邝霜

    2015-01-01

    Two different kinds of experimental techniques were used to in-situ study the austenite formation during intercritical annealing in C-Mn dual phase steel. The microstructure evolution was observed by confocal laser scanning microscope, and the austenite isothermal and non-isothermal transformation kinetics were studied by dilatometry. The results indicate that banded structure is produced for the reason of composition segregation and the competition between recrystallization and phase transformation. Austenite prefers to nucleate not only at ferrite/ferrite grain boundaries, but also inside the grains of ferrite. Furthermore, the austenitizing process is accomplished mainly via migration of the existing austenite/ferrite interface rather than nucleation of new grains. The incubation process can be divided into two stages which are controlled by carbon and manganese diffusion, respectively. During the incubation process, the nucleation rate of austenite decreases, and austenite growth changes from two-dimensional to one-dimensional. The partitioning coefficient, defined as the ratio of manganese content in the austenite to that in the adjacent ferrite, increases with increasing soaking time.

  12. Recrystallization and texture evolution during hot rolling of copper, studied by a multiscale model combining crystal plasticity and vertex models

    Science.gov (United States)

    Mellbin, Y.; Hallberg, H.; Ristinmaa, M.

    2016-10-01

    A multiscale modeling framework, combining a graph-based vertex model of microstructure evolution with a GPU-parallelized crystal plasticity model, was recently proposed by the authors. Considering hot rolling of copper, the full capabilities of the model are demonstrated in the present work. The polycrystal plasticity model captures the plastic response and the texture evolution during materials processing while the vertex model provides central features of grain structure evolution through dynamic recrystallization, such as nucleation and growth of individual crystals. The multiscale model makes it possible to obtain information regarding grain size and texture development throughout the workpiece, capturing the effects of recrystallization and heterogeneous microstructure evolution. Recognizing that recrystallization is a highly temperature dependent phenomenon, simulations are performed at different process temperatures. The results show that the proposed modeling framework is capable of simultaneously capturing central aspects of material behavior at both the meso- and macrolevel. Detailed investigation of the evolution of texture, grain size distribution and plastic deformation during the different processing conditions are performed, using the proposed model. The results show a strong texture development, but almost no recrystallization, for the lower of the investigated temperatures, while at higher temperatures an increased recrystallization is shown to weaken the development of a typical rolling texture. The simulations also show the influence of the shear deformation close to the rolling surface on both texture development and recrystallization.

  13. Microstructure and mechanical properties relation in cold rolled Al 2024 alloy determined by X-ray line profile analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mirzaei, M.; Roshan, M.R., E-mail: mammadroshan@yahoo.com; Jenabali Jahromi, S.A.

    2015-01-03

    Solution treated aluminum 2024 alloy sheets were subjected to rolling at room and cryogenic temperatures. Aging time and mechanical properties were evaluated by microhardness measurements and tensile test, respectively. Microstructural parameters were assessed by applying modified Williamson–Hall and modified Warren–Averbach methods to the X-ray diffraction patterns. Interestingly, the mechanical behavior of the different as-rolled and post-roll aged samples was in correlation with the sub-grain sizes and dislocation densities. The sub-grain sizes of the as-rolled samples were smaller than 40 nm, and the dislocation densities were larger than 7.7×10{sup 15} m{sup −2}, which is related to the high strength of the as-rolled samples. After aging treatment, the ductility of the rolled samples increased significantly, this was justified by the decline in the dislocation density.

  14. Modelling of Microstructural Evolution and Prediction of Mechanical Properties of Plain Carbon Strip Steel in Hot Rolling Process

    Institute of Scientific and Technical Information of China (English)

    Xiaochun SHA; Chunli MO; Dianzhong LI; Yiyi LI

    2004-01-01

    Based on hot rolling production line of strip steel, the of-line in-house software, termed as ROLLAN (Rolling Analysis),is developed. The code is mainly used to predict the evolution of temperature, rolling force, fraction and grain size of recrystallization, fraction and grain size of phase transformation and final mechanical properties. Almost all the processing parameters affecting microstructure and mechanical properties in the schedule from reheating to the coiling process are considered in detail. Self-learning coefficient is adopted to adjust the deviation between predicted and measured temperatures, such as roughing exit temperature (RT2), finishing exit temperature (FT7) and coiling temperature (CT). Due to the application of low-speed-threading, increasing-speed-rolling and decreasing-speeddelivery process during finishing rolling and different cooling condition, after coiling the thermal-mechanical history of different position, along strip longitudinal direction is different resulting in inhomogeneous mechanical properties.So the segments are divided along longitudinal direction to identify the variation of microstructure and mechanical properties. An example of plain carbon strip steel Q235 with various thickness is used to compare the calculated mechanical properties with measured ones. For the specific grade of Q235, the maximum deviation of tensile strength is less than 10.3 MPa, the yield strength is less than 13.2 MPa, and elongation is less than 1.99%. Further work will focus on the on-line application and consider the effect of macrosegregation and sulfur content of cast slab.

  15. HOT ROLLING OF A FERRITIC STAINLESS STEEL IN A STECKEL MILL: THERMOMECHANICAL AND MICROSTRUCTURAL CARACTERIZATION AND MATHEMATICAL MODELLING OF THE EVOLUTION OF RECRYSTALLIZED VOLUME FRACTION OF FERRITE

    Directory of Open Access Journals (Sweden)

    Willy Schuwarten Júnior

    2013-10-01

    Full Text Available A thermomechanical and a microstructure caracterization and a mathematical model of the evolution of the recrystallized volume fraction of ferrite in hot rolling in a Steckel mill have been carried out here. The proposed model is able to reasonably predict the observed in hot rolling, that is, there is 100% recrystallization of ferrite after roughing and partial recrystallization only after finishing

  16. Study of Sheet Steel Cold Rolling Pre-Emulsion Oil%薄钢板冷轧轧制油预乳液的研究

    Institute of Scientific and Technical Information of China (English)

    刘佳; 杨基和

    2011-01-01

    在薄钢板冷轧过程中,轧制油的润滑性、退火清净性、冷却性、离水展着性是至关重要的.选择世界一流的奎克公司冷轧轧制油为母油参考指标,以我国现行行业标准为乳液依据,进行预乳液轧制油的研究.首先进行基础油筛选,并对其油性、极压抗磨性、酸性等性能改进;在此基础上进行预乳液研制,着重考察其离水展着等性能.实验证明:以菜籽油为基础油,添加24%左右的高粘物质、1.7%含硫极压抗磨剂、1.3%酸性剂、11%复合乳化剂和3%的消泡剂,所得母油性能完全达到奎克公司薄钢板冷轧油标准,预乳液符合行业使用标准;其5%的乳化液静置24h后析皂量为4.3mI、2%乳化液静置7min后泡沫完全消除;以热重分析模拟退火环境,其油品残留量几乎为0.最终产品符合薄钢板冷轧水基液使用要求.%Developing cold rolling steel sheet pre-emulsion oil in the process of producing cold -rolled sheet, the properties of rolling oil, such as lubrication, cooling , plate-out and anneal free of annoyance, are essential. This study selected a world-class cold rolling oil of Quaker as benchmark for the mother oil, using our current industry standard for the research on pre-emulsion rolling oil. The base oil was selected first, its performance of oil, extreme pressure, anti -wear and acidity were improved. On the basis of the above, the study focused on the development of plate-out. The experiments proved that; using the rapeseed oil as base oil, adding about 24% of the high viscosity material, 1. 7% sulfur extreme pressure and anti-wear agent, 1.3% acidic agent, 11% complex emulsifier and 3% of antifoaming agents, the properties of oil reach benchmark of cold rolling oil from Quaker, pre-emulsion oil reaching industry standard. After 24h, 5% emulsion oil separating soap volume is 4. 3mL. 2% emulsion oil the bubbles are completely eliminated in 7min. Using method of

  17. Texture evolution of rolled Mg–3Al–1Zn alloy undergoing a {10-12} twinning dominant strain path change

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Hyuk [Light Metals Team, Korea Institute of Materials Science, Changwon 642-831 (Korea, Republic of); Hong, Seong-Gu, E-mail: sghong@kriss.re.kr [Division of Industrial Metrology, Korea Research Institute of Standards and Science, Daejeon 305-340 (Korea, Republic of); Lee, Jeong Hun [Graduate Institute of Ferrous Technology, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Huh, Yong-Hak [Division of Industrial Metrology, Korea Research Institute of Standards and Science, Daejeon 305-340 (Korea, Republic of)

    2015-10-15

    The texture modification, caused by {10-12}–{10-12} double twinning, in rolled Mg–3Al–1Zn alloy was investigated by carrying out consecutive in-plane compressions along two orthogonal directions in combination with an electron backscatter diffraction measurement and a Schmid factor analysis. The results revealed that the Schmid law still governs twin variant selection, thereby controlling texture evolution, however, the specific crystallographic feature of {10-12} twinned region in which the c-axis orients to the compression direction with a variation of ±30° on the rolling plane and one prismatic plane including the rotation axis of {10-12} twinning, corresponding to an a-axis, is aligned almost parallel to the rolling plane gives rise to a significantly different texture evolution of {10-12}–{10-12} double twinned region as compared to {10-12} twinned region. - Highlights: • Texture evolution, caused by {10-12}–{10-12} double twinning, was investigated. • Twin variant selection during double twinning is governed by the Schmid law. • Double twinned region has a significantly different texture compared with twinned region. • It is attributed to the specific crystallographic feature of {10-12} twinned region.

  18. Mechanism of surface texture evolution in pure copper strips subjected to double rolling

    Directory of Open Access Journals (Sweden)

    Xiyong Wang

    2014-02-01

    Full Text Available Developing ultra-thin copper foils with different surface roughness and microstructure has important significance for improving the service performance and reducing the production cost of high-end circuit boards. In this paper, pure copper strips with initial cube texture were subjected to a double rolling process (deformation amount ranges from 50% to 95%, and the surface textures evolution law and mechanism of double-rolled strips were studied by an X-ray diffraction technique. The results show that when a deformation amount increased from 50% to 70%, the grains of two surfaces rotate away from the cube orientation, and the formed textures of two surfaces mainly consisted of C, S and B orientation components. The orientation density values for these three components on bright surface only had slight difference; the orientation density values for C and S components were much larger than that for B components on a matt surface. When the deformation amount increased to 90%, the increase extents of orientation density values for C and S components were obviously larger than that for B components on a bright surface; the increase extents of orientation density values for these three components were almost the same on the matt surface. It has been found that when deformation amount reaches 95%, the grains orientation of bright surface were relatively concentrated, and the orientation density value for C texture obviously increased to 11.68 and that for B texture was only 3.15; the grains orientation of matt surface were relatively dispersed, and the orientation density value for C texture increased to 9.26 and that for B texture obviously increased to 6.35, and the density values of these two textures had less difference. For the condition of strong compressive and shear stress on the bright surface, grains were mainly rotating to C texture orientation; compared with the bright surface, “semi-free” deformation condition on the matt surface is

  19. 冷连轧机辊型配置对高强钢板形控制的影响%Effect of Roll Shape Configuration of Cold Continuous Mill on High-strength Strip Profile

    Institute of Scientific and Technical Information of China (English)

    吴彬; 张清东; 张晓峰

    2012-01-01

    针对薄规格高强钢板形控制困难问题,通过建立有限元模型分析了常规支撑辊+ CVC中间辊、CVC补偿支撑辊+ CVC中间辊及VCL+支撑辊+HVC中间辊3种代表性辊型配置对高强度冷轧板的板形控制能力的影响.与其他2种辊型配置方案相比,VCL+支撑辊+HVC中间辊辊型配置的承载辊缝的凸度调节域较大、横向刚度较高,辊间接触压力较小.实际生产表明,在该辊型配置方案下,高强度带钢的板形控制精度较高,支撑辊磨损得到有效改善.%To the problem of the shape of high-strength sheet difficult to control, the influences of three representative forms of roll profile configuration on high-strength strip shape control in CVC cold continuous rolling mill are compared by FEM model, which are conventional back-up roll + CVC intermediate roll, back-up roll with CVC compensation + CVC intermediate roll, VCL+ back-up roll + HVC intermediate roll. Compared with the other two roll profile configuration, the configuration of VCL+ back-up roll + HVC intermediate roll increases crown adjustment room and lateral stiffness of loaded roll gap, decreases contact pressure between rolls. The production practice shows that the control accuracy of high-strength strip shape and wear of back-up roll are improved by it.

  20. Recrystallization behaviour of cold rolled aluminium from cast strips; Recristalizacion de bandas de aluminio procedentes de colada continua, laminadas en frio

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Ilzarbe, J.; Faustmann Salas, J.; Suarez Sandra, A.

    2000-07-01

    This paper revises the literature on the problems in recrystallization of cold rolled cast strips. The phenomenon of the precipitation previous or simultaneous to recrystallization, that may affect the nucleation of the recrystallization, is explained. The use of TTT (Time, Temperature, Transformation) curves to obtain the critical time and temperature without cutting the nose of the precipitation zone are examined For Al-Mn alloys it is also explained the obtainment of CTT (Concentration, Time, Temperature) curves and grain size diagrams on the basis of heating rate and Mn in solid solution obtainment. (Author) 47 refs.

  1. Synergism between rare earth cerium(IV) ion and vanillin on the corrosion of cold rolled steel in 1.0 M HCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Li Xianghong [Department of Fundamental Courses, Southwest Forestry University, Kunming 650224 (China)], E-mail: xianghong-li@163.com; Deng Shuduan [Department of Wood Science and Technology, Southwest Forestry University, Kunming 650224 (China); Fu Hui [Department of Fundamental Courses, Southwest Forestry University, Kunming 650224 (China); Mu Guannan [Department of Chemistry, Yunnan University, Kunming 650091 (China)

    2008-12-15

    The synergism between rare earth cerium(IV) ion and vanillin on the corrosion of cold rolled steel (CRS) in 1.0 M HCl solution was first investigated by weight loss, potentiodynamic polarization, ultraviolet and visible spectrophotometer (UV-vis), X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). The results revealed that vanillin had a moderate inhibitive effect, and the adsorption of vanillin obeyed the Temkin adsorption isotherm. For rare earth Ce{sup 4+}, it had a negligible effect. However, incorporation of Ce{sup 4+} with vanillin significantly improved the inhibition performance, and produced strong synergistic inhibition effect. Depending on the results, the synergism mechanism was proposed.

  2. Design and Analysis of the Oblique Blade Shears for Cold-Rolled Strip%冷轧带钢斜刃剪设计及分析

    Institute of Scientific and Technical Information of China (English)

    徐利璞

    2014-01-01

    针对冷轧带钢斜刃剪,从剪切机理入手,分析比较了几种常用剪切力计算公式,阐明了斜刃剪的设计要点,对斜刃剪的设计具有理论指导意义。%For oblique blade throat shears of cold-rolled strip steel, first this paper studies shear mecha-nism, then analyzes and compares the shear force of several commonly used formulas , and clarifies the design fea-tures.It offers theoretical guidance for the design of oblique blade shears .

  3. Method of Maintaining the Required Values of Surface Roughness and Prediction of Technological Conditions for Cold Sheet Rolling

    Directory of Open Access Journals (Sweden)

    Valíček J.

    2014-06-01

    Full Text Available The paper is based on results obtained from topography of surfaces of sheets rolled from deep-drawing steel of the type KOHAL grade 697, non-alloy low-carbon structural steel EN 10263-2:2004 and aluminium. The presented results document correctness of the assumption that the rolling force Froll increases with the increasing reduction Δh and the quality of the rolled surface is improved at the simultaneous increasing of strength of rolled sheets and the decreasing of size of structural grains. The experiment was performed on the two-high rolling stand DUO 210 SVa, which enables only non-continuous technology in contrast to the rolling mill with continuous reduction on one sheet in several degrees on rolling trains, in consequence of which the obtained height parameters of the section are in close correlation with the predicted dependence. Contribution of the work consists in the creation of a mathematical model (algorithm for predicting technological parameters of the two-high rolling stand DUO 210 SVa at change of the absolute reduction Δh, for example for a deep-drawing steel of the type KOHAL grade 697 and non-alloy lowcarbon structural steel PN EN 10263-2:2004 and aluminium, and also in the development of a method of calculation applicable to any material being rolled in general, because the authors have found that various materials can be differentiated by a derived analytical criterion IKP. This criterion is a function of ratio between the modulus of elasticity of reference material and that of actually rolled material. The reference material is here deep-drawing steel of the type KOHAL grade 697. Verification was carried out by measuring changes of final surface roughness profile and final strength of rolled sheets of the stated materials in relation to reductions and those were compared with theoretically predicted values. It is possible to identify and predict on the basis of this algorithm an instant state of surface topography in

  4. Method of Maintaining the Required Values of Surface Roughness and Prediction of Technological Conditions for Cold Sheet Rolling

    Science.gov (United States)

    Valíček, J.; Harničárová, M.; Kušnerová, M.; Zavadil, J.; Grznárik, R.

    2014-06-01

    The paper is based on results obtained from topography of surfaces of sheets rolled from deep-drawing steel of the type KOHAL grade 697, non-alloy low-carbon structural steel EN 10263-2:2004 and aluminium. The presented results document correctness of the assumption that the rolling force Froll increases with the increasing reduction Δh and the quality of the rolled surface is improved at the simultaneous increasing of strength of rolled sheets and the decreasing of size of structural grains. The experiment was performed on the two-high rolling stand DUO 210 SVa, which enables only non-continuous technology in contrast to the rolling mill with continuous reduction on one sheet in several degrees on rolling trains, in consequence of which the obtained height parameters of the section are in close correlation with the predicted dependence. Contribution of the work consists in the creation of a mathematical model (algorithm) for predicting technological parameters of the two-high rolling stand DUO 210 SVa at change of the absolute reduction Δh, for example for a deep-drawing steel of the type KOHAL grade 697 and non-alloy lowcarbon structural steel PN EN 10263-2:2004 and aluminium, and also in the development of a method of calculation applicable to any material being rolled in general, because the authors have found that various materials can be differentiated by a derived analytical criterion IKP. This criterion is a function of ratio between the modulus of elasticity of reference material and that of actually rolled material. The reference material is here deep-drawing steel of the type KOHAL grade 697. Verification was carried out by measuring changes of final surface roughness profile and final strength of rolled sheets of the stated materials in relation to reductions and those were compared with theoretically predicted values. It is possible to identify and predict on the basis of this algorithm an instant state of surface topography in respect to variable

  5. The three-dimensional evolution of a plane mixing layer. Part 1: The Kelvin-Helmholtz roll-up

    Science.gov (United States)

    Rogers, Michael M.; Moser, Robert D.

    1991-01-01

    The Kelvin Helmholtz roll up of three dimensional, temporally evolving, plane mixing layers were simulated numerically. All simulations were begun from a few low wavenumber disturbances, usually derived from linear stability theory, in addition to the mean velocity profile. The spanwise disturbance wavelength was taken to be less than or equal to the streamwise wavelength associated with the Kelvin Helmholtz roll up. A standard set of clean structures develop in most of the simulations. The spanwise vorticity rolls up into a corrugated spanwise roller, with vortex stretching creating strong spanwise vorticity in a cup shaped region at the vends of the roller. Predominantly streamwise rib vortices develop in the braid region between the rollers. For sufficiently strong initial three dimensional disturbances, these ribs collapse into compact axisymmetric vortices. The rib vortex lines connect to neighboring ribs and are kinked in the opposite direction of the roller vortex lines. Because of this, these two sets of vortex lines remain distinct. For certain initial conditions, persistent ribs do not develop. In such cases the development of significant three dimensionality is delayed. When the initial three dimensional disturbance energy is about equal to, or less than, the two dimensional fundamental disturbance energy, the evolution of the three dimensional disturbance is nearly linear (with respect to the mean and the two dimensional disturbances), at least until the first Kelvin Helmholtz roll up is completed.

  6. Temperature and number evolution of cold cesium atoms inside a wall-coated glass cell

    Institute of Scientific and Technical Information of China (English)

    黄家强; 张建伟; 王时光; 王力军

    2015-01-01

    We report an experimental study on the temperature and number evolution of cold cesium atoms diffusively cooled inside a wall-coated glass cell by measuring the absorption profile of the 62S1/2 (F=4)→62P3/2(F0=5) transition line with a weak probe laser in the evolution process. We found that the temperature of the cold atoms first gradually decreases from 16 mK to 9 mK, and then rapidly increases. The number of cold atoms first declines slowly from 2.1 × 109 to 3.7 × 108 and then falls drastically. A theoretical model for the number evolution is built and includes the instantaneous temperature of the cold atoms and a fraction p, which represents the part of cold cesium atoms elastically reflected by the coated cell wall. The theory is overall in good agreement with the experimental result, and a nonzero value is obtained for the fraction p, which indicates that the cold cesium atoms are not all heated to the ambient temperature by a single collision with the coated cell wall. These results can provide helpful insight for precision measurements based on diffuse laser cooling.

  7. Tracking the evolution of a cold stress associated gene family in cold tolerant grasses

    DEFF Research Database (Denmark)

    Sandve, Simen R; Rudi, Heidi; Asp, Torben

    2008-01-01

    Background Grasses are adapted to a wide range of climatic conditions. Species of the subfamily Pooideae, which includes wheat, barley and important forage grasses, have evolved extreme frost tolerance. A class of ice binding proteins that inhibit ice re-crystallisation, specific to the Pooideae...... to the repeat motifs of the IRI-domain in cold tolerant grasses. Finally we show that the LRR-domain of carrot and grass IRI proteins both share homology to an Arabidopsis thaliana LRR-trans membrane protein kinase (LRR-TPK). Conclusion The diverse IRI-like genes identified in this study tell a tale...... of a complex evolutionary history including birth of an ice binding domain, a burst of gene duplication events after cold tolerant grasses radiated from rice, protein domain structure differentiation between paralogs, and sub- and/or neofunctionalisation of IRI-like proteins. From our sequence analysis we...

  8. Mathematical modeling and simulation of the interface region of a tri-layer composite material, brass-steel-brass, produced by cold rolling

    Institute of Scientific and Technical Information of China (English)

    H. Arabi; S.H. Seyedein; A. Mehryab; B.Tolaminejad

    2009-01-01

    The object of this study was to find the optimum conditions for the production of a sandwich composite from the sheets of brass-steel-brass. The experimental data obtained during the production process were used to validate the simulation program, which was written to establish the relation between the interface morphology and the thickness reduction amount of the composite. For this purpose, two surfaces of a steel sheet were first prepared by scratching brushing before inserting it between two brass sheets with smooth surfaces. Three sheets were then subjected to a cold rolling process for producing a tri-layer composite with various thick-nesses. The sheet interface after rolling was studied by different techniques, and the bonding strength for each rolling condition was determined by peeling test. Moreover, a relation between interfacial bonding strength and thickness reduction was found. The simu-lation results were compared with the experimental data and the available theoretical models to modify the original simulation pro-gram with high application efficiency used for predicting the behavior of the interface under different pressures.

  9. In situ observation of texture and microstructure evolution during rolling and globularization of Ti-6Al-4V

    KAUST Repository

    Warwick, Jonnathan L W

    2013-03-01

    The evolution of texture in β-annealed Ti-6Al-4V during α-β rolling and so-called recrystallization annealing has been examined using synchrotron X-ray diffraction and ex situ characterization. During rolling, the initial α (0 0 0 2) texture softens and the colony α becomes kinked. During globularization, the texture strengthens as highly strained (and hence misoriented) areas of the laths disappear and this strengthening continues once coarsening of the primary α becomes dominant. At shorter heat treatment times the αs laths that form on cooling do so with a range of variant-related orientations to the β, but at longer annealing times this αs takes on the orientation of the surrounding αp. The implications for the mechanical performance of macrozone-containing bimodal Ti-6Al-4V material are discussed. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Study on Technological Parameters of YAG Laser Cutting Cold Rolled Steel Sheets%YAG激光切割冷轧钢板的工艺参数研究

    Institute of Scientific and Technical Information of China (English)

    关雷; 史子木; 舒胜威

    2014-01-01

    实验使用YAG脉冲激光切割机切割Q235薄冷轧钢板。基于激光切割理论,采用正交试验对激光切割工艺参数进行优化。以切口宽度和切口的表面粗糙度为衡量标准,通过对比得出切割0.7 mm、1.0 mm、1.5 mm厚的Q235冷轧钢板的最优切割参数。%Q235 cold rolled steel sheets are cut by YAG pulse laser in this experiment. We optimize the process of laser cutting with orthogonal test depend upon the theory of laser cutting. Summarizing optimal cutting quality and the best process parameters of cutting 0.7, 1.0, 1.5 mm cold rolled steel sheet should be reached by measuring the joint-cutting width and comparison the surface roughness of incision.

  11. Combined deterministic and stochastic approaches for modeling the evolution of food products along the cold chain. Part I: Methodology

    OpenAIRE

    Flick, D.; Hoang, H.M.; Alvarez, G.; Laguerre, O.

    2012-01-01

    Many deterministic models have been developed to describe heat transfer in the cold chain and to predict the thermal and microbial evolution of food products. However, different product items will have different evolutions because of the variability of logistic supply chain, equipment design and operating conditions, etc. The objective of this study is to propose a general methodology to predict the evolution of food products and its variability along a cold chain. This evolution is chara...

  12. Influence of annealing treatment on micro/macro-texture and texture dependent magnetic properties in cold rolled FeCo–7.15V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hasani, S., E-mail: s.hasani@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, 84156-83111 Isfahan (Iran, Islamic Republic of); Shamanian, M.; Shafyei, A.; Behjati, P. [Department of Materials Engineering, Isfahan University of Technology, 84156-83111 Isfahan (Iran, Islamic Republic of); Nezakat, M. [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, Canada S7N 5A9 (Canada); Fathi-Moghaddam, M. [Department of Materials Science and Engineering, Sharif University of Technology, 11365-9466 Tehran (Iran, Islamic Republic of); Szpunar, J.A. [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, Canada S7N 5A9 (Canada)

    2015-03-15

    The influence of annealing treatment on macro- and micro-texture of cold-rolled FeCo–7.15V ferromagnetic ultra-thin foils were studied. The microstructural studies performed by field emission scanning electron microscope (FE-SEM) showed the formation of paramagnetic precipitations ((Fe, Co){sub 3}V) during annealing. During cold rolling of the FeCo–7.15V magnet, the texture components of type (113)[11{sup ¯}0], (001)[11{sup ¯}0], (111)[11{sup ¯}0], and (111)[12{sup ¯}1], all related to α and γ-fibers were formed. X-ray diffraction (XRD) and local texture measurements performed by electron backscatter diffraction (EBSD) were made on the annealed samples. Both methods revealed that the recrystallized samples have texture characterized by γ fiber component, when the recovered samples were characterized by α fiber component. The grain boundary character distribution (GBCD) and microstructures of the material were analyzed using EBSD. The experimental results showed that annealing at 870 °C for 2 h resulted in a high frequency of twin boundaries. The maximum CSL density could reach 7.5% under annealing conditions: at 870 °C for 2 h. Finally, in order to investigate the texture influence on the magnetic properties, magnetic properties of the samples were measured using a vibrating sample magnetometer (VSM). The results showed an improvement in remanence induction (B{sub r}) with the formation of hard axis <100>. - Highlights: • This paper describes the macro- and micro-texture of Fe–Co–7.15V after rolling and annealing conditions. • The grain boundary character distribution (GBCD) and microstructures of the material were analyzed using EBSD. • The texture dependence magnetic properties of Fe–Co–7.15V were studied.

  13. Study on five primary models in AGC system of cold rolling mill%冷轧机AGC控制系统模型研究

    Institute of Scientific and Technical Information of China (English)

    王斌; 寇鹏; 窦锋

    2011-01-01

    高精度轧制技术对冷轧机液压AGC系统的控制精度提出了更高的要求,本文对AGC系统中位置控制器、伺服放大器、位移传感器、压力传感器、控制调节器五个主要模型进行分析,对模型结构中测厚仪环节、延时器环节、死区环节、限幅器环节进行数学模型分析,分析了控制系统中各种因数对控制精度的影响并选择合理的控制策略,对冷轧机液压AGC系统的优化设计及系统控制性能的研究提供了基础.%As the high-precision rolling technology has put forward a higher requirement for the control accuracy to the hydraulic AGC(automatic gauge control)system of cold rolling mill, the models of position controller, servo amplifier, displacement sensor, pressure sensor and control regulator in AGC system are investigated, and the mathematic model analysis of gauge link, delay link, dead zone link, limiter link in the model structure is performed. The influence of various factors in the control system on control accuracy is analyzed. The control strategy is selected reasonably. It is significant for designing the hydraulic AGC system of cold rolling mill and studying the response capacities of the system.

  14. A comparative experimental and numerical study to investigate the relative merits of convectors and ``C'' inserts in cooling cold-rolled coils

    Science.gov (United States)

    Bhattacharya, Tathagata; Chakraborty, Debadi; Singh, Vikas

    2006-12-01

    The coil cooling and storage unit (CCSU) is used to cool cold-rolled coils to the temper rolling temperature after the annealing cycle is over at the batch annealing furnace (BAF) in a cold rolling mill (CRM). In the CCSU, the coils are kept on the cooling bases for any fixed time irrespective of the grade and tonnage. Therefore, the need for a mathematical model to accurately predict the cooling time of the coils was felt. The current study involves experimental and numerical analysis of a stack of coils with respect to heat transfer and fluid flow. A comparative study was carried out to ascertain the relative merits of convectors and “C” inserts (CIs) in the cooling the coils. The air flow distribution for the case of different convectors and CIs was measured by means of a full scale physical model. Two different mathematical models were applied to model the fluid flow and flow distribution through the stack of coils. The first flow model uses the hydraulic resistance concept for estimating the air flow rate distribution, whereas the second flow model uses commercial computational fluid dynamics (CFD) software and predicts the velocity distribution in the flow path between two coils in a stack. The predictions from these two models compare well with the experimental data. The flow models were used to calculate the average heat-transfer coefficient in different flow passages in a stack. The heat-transfer coefficients thus obtained were used to tune and validate a two-dimensional transient heat-transfer model of coils. The heat-transfer model predicts the cooling time of coils accurately and also suggests a possible reduction of cooling time if CIs are used in place of convectors.

  15. Microstructural evaluation of Ti-35Nb-7,5 T alloy deformed by cold rolling and annealed; Avaliacao microestrutural da liga Ti-35Nb-7,5Ta deformada por laminacao a frio e recozida

    Energy Technology Data Exchange (ETDEWEB)

    Giudice, M.L.C.; Hayama, A.O.F.; Button, S.T.; Caram, R., E-mail: mlcgiudice@fem.unicamp.b [Universidade Estadual de Campinas (DEMA/FEM/UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia de Materiais

    2010-07-01

    This work presents the main results of microstructural characterization of Ti- 35Nb-7.5Ta (% in weight) deformed by cold rolling and annealed. Samples were obtained by electric arc melting, heat treated at 1000 deg C for 8 hours and water quenched. Samples were deformed by cold rolling in multiple passes up to a maximum reduction of 84%. Deformed samples were encapsulated in quartz under vacuum and annealed at 600, 700 e 800 deg C, in variable times and water quenched. Characterization was carried out using light optical microscopy, X-ray diffraction, Vickers hardness test and acoustic emission measurements to determine the Young's modulus. The results show the orientation occurrence of the martensitic phase in relation to the cold rolling direction in deformed samples. In samples annealed at 600 deg C recovery is predominant and samples annealed at 800 deg C for 60 min are fully recrystallized. (author)

  16. Application of Water Treatment Process for Cold-rolling Waste Water to Be Drained into Natural Water%排至自然水体的冷轧废水处理工艺应用

    Institute of Scientific and Technical Information of China (English)

    尹军喜

    2014-01-01

    The water treatment process for cold rolling waste water to be drained into natural water is introduced. Treatment methods for cold rolling waste water containing chrome, acid, oil, temper mill fluid and thin alkali are summarized. The main problems and functions of the process are also analyzed. This water treatment process has reached the advanced level in the field of domestic cold rolling waste water treatment.%介绍了排至自然水体的冷轧废水处理工艺,综述了冷轧废水中含铬废水、含酸废水、含油废水、平整液废水、稀碱废水的处理方法,对主要问题和功能进行了分析,其处理工艺达到了国内冷轧废水的先进水平。

  17. Non-isothermal microcalorimetric evaluations in quenched and in cold-rolled Cu-9Ni-5.5Sn alloys; Evaluaciones microcalorimetricas no-isotermas en aleaciones de Cu-9Ni-5,5Sn templadas y deformadas en frio

    Energy Technology Data Exchange (ETDEWEB)

    Donoso, E.; Dianez, M. J.; Criado, J. M.

    2012-11-01

    The thermal aging of both a quenched and a cold rolled homogeneous supersaturated Cu-9 % wt Ni-5.5 wt % Sn alloy has been studied from differential scanning calorimetry (DSC) and microhardness measurements. An increase of the hardness during the aging of the quenched sample, because of the precipitation of a {gamma} phase, takes place. On the contrary, no hardness increase was observed during the aging of the cold rolled sample. A theoretical analysis of the enthalpy determined from the first DSC exothermic peak suggests that a segregation of the solute towards the dislocations occurs during the aging of the cold rolled alloy. The values of the n Avrami-Erofeev coefficients estimated from the kinetic analysis supports the above interpretations. (Author)

  18. Political Evolution at NATO Level in Post Cold War Era

    Directory of Open Access Journals (Sweden)

    Tomescu Cătălin Tomiţă

    2015-06-01

    Full Text Available The beginning of the post Cold era sounds like that: „The world has changed dramatically. The Alliance has made an essential contribution. The peoples of North America and the whole of Europe can now join in a community of shared values based on freedom, democracy, human rights and the rule of law. As an agent of change, a source of stability and the indispensable guarantor of its members' security, our Alliance will continue to play a key role in building a new, lasting order of peace in Europe: a Europe of cooperation and prosperity”[1].

  19. Analysis of Orange Peel Defects in Cold Rolled Sheet%冷轧板冲压橘皮缺陷分析

    Institute of Scientific and Technical Information of China (English)

    李洪翠

    2013-01-01

    Because orange peel defects appeared in the surface of St13 cold-rolled sheet after deep punching, seriously affecting the use performance, the process parameters and the samples from the sheet with defects were analyzed. The results showed that the chemical composition met the requirement and the annealing parameters were regular, but mixed grain phenomenon in the microstructure of the sample and a smell yield point jog existed in the tension test of the simple. The fluctuation of hot rolling process and small rolling force in leveling process are main reasons caused the orange peel defects. Through strengthening process control in hot rolling and optimizing leveling parameter, the yield point jog and orange peel defect were eliminated.%  由于St13冷轧板冲压后表面出现橘皮缺陷,严重影响使用性能,对钢板生产工艺过程参数和缺陷板取样进行分析,结果表明,化学成分符合要求,退火工艺参数正常,但缺陷试样组织存在一定混晶现象,试样拉伸试验存在微小屈服平台,说明热轧工艺波动和冷轧平整力不足是导致橘皮缺陷产生的主要原因,通过加强热轧工艺控制,优化平整工艺参数,消除了屈服平台和冲压橘皮缺陷。

  20. Hardness loss and microstructure evolution of 90% hot-rolled pure tungsten at 1200-1350°C

    DEFF Research Database (Denmark)

    Yu, Ming; Wang, Kang; Zan, Xiang

    2017-01-01

    Tungsten is a promising plasma-facing material because of its low sputtering yield, high melting point and high thermal conductivity. The hardness loss and microstructure evolution of pure tungsten hot-rolled to 90% thickness reduction is investigated by isothermal annealing at temperature range...... of 1200-1350°C. Changes in the mechanical properties caused by recovery and recrystallization during heat treatment are detected by Vickers hardness measurements. Additionally, the microstructural evolution is analyzed with light optical microscopy and X-ray diffraction. The results indicate...... that the hardness evolution can be divided into two stages: recovery and recrystallization. Recrystallization of W90 in the temperature range of 1200 to1350°C is governed by the same activation energy as grain boundary diffusion. The average recrystallized grain size is larger for lower annealing temperatures....

  1. Microstructure evolution of cold-sprayed coating during deposition and through post-spraying heat treatment

    Institute of Scientific and Technical Information of China (English)

    LI Chang-jiu; LI Wen-ya

    2004-01-01

    The microstructural features of cold-sprayed coatings were investigated using Cu, Ti and Zn feedstocks by optical microscopy, scanning electron microscopy and transmission electron microscopy to reveal the microstructure evolution mechanisms in cold spray. Four typical effects including tamping, refinement, impact-induced fusion and annealing were examined on microstrueture. It is found that the microstructure of cold spray coating is remarkably influenced by spray materials. Ti coatings consist of evident porous layer and Cu coatings present a limited porous layer only near the surface. It is clear that the successive tamping effect and dynamic refinement of grains significantly influence the microstructure evolution of cold-sprayed coating. The tamping effect leads to the densification of porous coating layer gradually and the refinement effect leads to the formation of fine microstructure. It is considered that the large difference in the formation of porous layer is attributed to the dynamic impact pressure and hardenability of materials. It is also found that the impact-induced fusion during deposition of Zn coating can also modify the interfacial microstructure between particles in cold spray coating. Moreover, the nanocrystalline phase can be formed at the interfaces among particles resulting from the localized melting of the interfaces and tamping effect. Furthermore, the annealing treatment can modify the microstructure and property of a cold-sprayed coating.

  2. Evolution of viviparity: a phylogenetic test of the cold-climate hypothesis in phrynosomatid lizards.

    Science.gov (United States)

    Lambert, Shea M; Wiens, John J

    2013-09-01

    The evolution of viviparity is a key life-history transition in vertebrates, but the selective forces favoring its evolution are not fully understood. With >100 origins of viviparity, squamate reptiles (lizards and snakes) are ideal for addressing this issue. Some evidence from field and laboratory studies supports the "cold-climate" hypothesis, wherein viviparity provides an advantage in cold environments by allowing mothers to maintain higher temperatures for developing embryos. Surprisingly, the cold-climate hypothesis has not been tested using both climatic data and phylogenetic comparative methods. Here, we investigate the evolution of viviparity in the lizard family Phrynosomatidae using GIS-based environmental data, an extensive phylogeny (117 species), and recently developed comparative methods. We find significant relationships between viviparity and lower temperatures during the warmest (egg-laying) season, strongly supporting the cold-climate hypothesis. Remarkably, we also find that viviparity tends to evolve more frequently at tropical latitudes, despite its association with cooler climates. Our results help explain this and two related patterns that seemingly contradict the cold-climate hypothesis: the presence of viviparous species restricted to low-elevation tropical regions and the paucity of viviparous species at high latitudes. Finally, we examine whether viviparous taxa may be at higher risk of extinction from anthropogenic climate change.

  3. Curriculum Evolution at Air Command and Staff College in the Post-Cold War Era

    Science.gov (United States)

    Donovan, William Robert, II.

    2010-01-01

    This qualitative study used a historical research method to eliminate the gap in the historical knowledge of Air Command and Staff College (ACSC) curriculum evolution in the post-Cold War era. This study is the only known analysis of the forces that influenced the ACSC curriculum and the rationale behind curricular change at ACSC in the post-Cold…

  4. Energy-Dispersive X-Ray Diffraction Studies of the Texture in Cold-Rolled Alpha-Beta Brass

    DEFF Research Database (Denmark)

    Szpunar, J.; Gerward, L.

    1980-01-01

    It is shown that energy-dispersive X-ray diffraction can be used for simultaneous measurement of several pole figures and that the accuracy is sufficient for the determination of the crystallite orientation distribution. The method is applied to the study of the texture in Cu-43 wt % Zn duplex...... alpha-beta brass rolled to 80% reduction....

  5. The structure and evolution of cold dark matter halos

    CERN Document Server

    Diemand, Jürg

    2009-01-01

    In the standard cosmological model a mysterious cold dark matter (CDM) component dominates the formation of structures. Numerical studies of the formation of CDM halos have produced several robust results that allow unique tests of the hierarchical clustering paradigm. Universal properties of halos, including their mass profiles and substructure properties are roughly consistent with observational data from the scales of dwarf galaxies to galaxy clusters. Resolving the fine grained structure of halos has enabled us to make predictions for ongoing and planned direct and indirect dark matter detection experiments. While simulations of pure CDM halos are now very accurate and in good agreement (recently claimed discrepancies are addressed in detail in this review), we are still unable to make robust, quantitative predictions about galaxy formation and about how the dark matter distribution changes in the process. Whilst discrepancies between observations and simulations have been the subject of much debate in th...

  6. Microstructure evolution of single crystal copper wires in cold drawing

    Institute of Scientific and Technical Information of China (English)

    CHEN; Jian; YAN; Wen; WANG; XueYan; FAN; XinHui

    2007-01-01

    The deformation microstructure evolution of single crystal copper wires produced by OCC method has been studied with the help of TEM, EBSD and OM. The results show that there are a small number of dendrites and twins in the undeformed single crystal copper wires. However, it is difficult to observe these dendrites in deformed single crystal copper wires. The structure evolution of deformed single crystal copper wires during drawing process can be divided into three stages. When the true strain is lower than 0.94, macroscopic subdivision of grains is not evident, and the microscopic evolution of deformed structure is that the cells are formed and elongated in drawn direction. When the true strain is between 0.94 and 1.96, macroscopic subdivision of grains takes place, and the number of microbands located on {111} and cell blocks is much more than that with the true strain lower than 0.94. When the true strain is larger than 1.96, the macroscopic subdivision of grains becomes more evident than that with the true strain between 0.94 and 1.96, and S-bands structure and lamellar boundaries will be formed. From EBSD analysis, it is found that part of texture resulting from solidifying is transformed into and due to shear deformation, but texture component is still kept in majority. When the true strain is 0.94, the misorientation angle of dislocation boundaries resulting from deformation is lower than 14°. However, when the true strain arrives at 1.96, the misorientation angle of some boundaries will be greater than 50°, and the peak of misorientation angle distribution produced by texture evolution is located in the range between 25° and 30°.

  7. Microstructure evolution and fracture behavior in superplastic deformation of hot-rolled AZ31 Mg alloy sheet

    Energy Technology Data Exchange (ETDEWEB)

    Yin, D.L.; Zhang, K.F.; Wang, G.F. [School of Material Science and Technology, Harbin Inst. of Tech. (China)

    2005-07-01

    Fine-grained AZ31 magnesium alloy sheets were prepared through hot rolling process. The superplastic properties of hot-rolled AZ31 Mg alloy was examined by uniaxial tensile tests at a temperature range 250{proportional_to}450 C and strain rate range 0.7 x 10{sup -3}{proportional_to}1.4 x 10{sup -1} s{sup -1}. Optical and scanning electronic microscope (SEM) were used to observe the microstructure evolution and fracture behavior in superplastic deformation of AZ31 Mg alloy and the values of deformation activation energy at various temperatures were calculated. It is demonstrated that, the hot-rolled AZ31 alloy begins to exhibit superplasticity from 300 C and a maximum elongation of 362.5% is obtained at 400 C and 0.7 x 10{sup -3} s{sup -1}. In the temperature range 300{proportional_to}400 C, the dominant superplastic deformation mechanism is grain boundary sliding (GBS) controlled by grain boundary diffusion and the influence of temperature on the fracture behavior of AZ31 Mg alloy is characterized by the change from dimple-aggregating type to intercrystalline one. (orig.)

  8. Tracking the evolution of a cold stress associated gene family in cold tolerant grasses

    DEFF Research Database (Denmark)

    Sandve, Simen R; Rudi, Heidi; Asp, Torben

    2008-01-01

    subfamily lineage, have been identified in perennial ryegrass and wheat, and these proteins are thought to have evolved from a leucine-rich repeat phytosulfokine receptor kinase (LRR-PSR)-like ancestor gene. Even though the ice re-crystallisation inhibition function of these proteins has been studied...... of a complex evolutionary history including birth of an ice binding domain, a burst of gene duplication events after cold tolerant grasses radiated from rice, protein domain structure differentiation between paralogs, and sub- and/or neofunctionalisation of IRI-like proteins. From our sequence analysis we......Background Grasses are adapted to a wide range of climatic conditions. Species of the subfamily Pooideae, which includes wheat, barley and important forage grasses, have evolved extreme frost tolerance. A class of ice binding proteins that inhibit ice re-crystallisation, specific to the Pooideae...

  9. 冷轧无取向硅钢横向厚差控制%Transverse Thickness Deviation Control of Non-oriented Silicon Steel during Cold Rolling

    Institute of Scientific and Technical Information of China (English)

    何安瑞; 邵健; 孙文权; 管长林; 沈新玉; 张建平

    2011-01-01

    Medium-low grade non-oriented silicon steel is roiled often by universal crown mill(UCM) during cold rolling. Its shape quality is dependent on the coordinated control of several shape aadjustment devices of UCM. In order to understand the shape control characteristics of UCM, coupling model of six-high rolling mill, based on two-dimensional varying thickness finite element roils elastic deformation model and three-dimeusional finite difference strip plastic deformation model, is setup for the detailed analysis of shape control performances of UCM, including the shape regulation and control efficacy of work roll bending, intermediate roll bending and its shiffing, contact force distribution between rolls, et al. On the basis of these, shape control tactics of UCM is put forward for instructing the production, and also its deficiency in the control of transverse thickness deviation is pointed out. In view of the large transverse thickness deviation of non-oriented silicon steel rolled by UCM in industrial production, edge variable crown(EVC) work roil with high order curve function is developed after large amount of simulating calculation. By using this work roll, the percentage of transverse thickness deviation of all varieties of non-oriented silicon steel not greater than 10 μm rises from 24% to 99% after the application of EVC work roll. The average of transverse thickness deviation is less than 6 μm, far less than the previous 13 μm before the use of EVC.%冷轧中中低牌号的无取向硅钢多采用万能凸度轧机(Universal crown mill,UCM)生产,其板形好坏受制于UCM轧机板形调节手段的协调使用.为掌握UCM轧机的板形控制特点,建立基于二维变厚度有限元的辊系弹性变形和基于三维差分的轧件塑性变形的六辊轧机耦合模型,对UCM轧机的板形调控性能进行详尽的分析,包括工作辊和中间辊弯辊、中间辊窜辊的调控功效、辊间接触压力分布等.在此基础上,提出

  10. 冷轧机张力控制系统分析%Cold Rolling Mill Tension Control System Analysis

    Institute of Scientific and Technical Information of China (English)

    吴俊

    2015-01-01

    The stability of tension directly affects the quality of the rolled products, therefore, constant tension control rolling mill automatic control system is a key technology. Expounds the role of tension in mill production, the concept of tension, tension control and influence of the basic principles of tension fluctuation factor.%张力的稳定性直接影响着轧制产品的质量,因此,轧机的恒张力控制是轧机自动控制系统中的关键技术。主要阐述了张力在轧机生产中的作用、张力的概念、张力控制的基本原理和影响张力波动的因素。

  11. Modelling profile and shape evolution during hot rolling of steel strip

    Directory of Open Access Journals (Sweden)

    Zambrano, P. C.

    2006-10-01

    Full Text Available Profile and shape control are required to assure the dimensional quality of rolled strip. Occurrence of waves either at the edges or centre of strips is attributed to inconsistency between the entry and exit cross-section profiles of the stock within a given rolling pass. The exit profile of the strip can be computed by considering that the such profile is the complement of that of the roll-gap, which is affected by wear, thermal expansion and distortion of the work rolls A computer model was developed to predict the profile of the roll-gap taking into account the thermal gradient within the work roll and the distortion caused by the acting forces. It was possible to establish a good correlation between the profiles of strips obtained from trials carried out on site, and the predictions of the model. The model allows for the prediction of the onset of shape defects from changes in the profile of rolled strips.

    Se requiere del control del perfil y forma para asegurar la calidad dimensional de la cinta laminada. La presencia de ondulaciones, ya sea en la orilla o al centro de la cinta, se atribuye a la inconsistencia entre el perfil de la sección transversal de la pieza a la entrada y a la salida, en un dado paso. El perfil de salida de la cinta se puede calcular al suponer que dicho perfil es el complemento del entrehierro, que es afectado por desgaste, expansión térmica y distorsión de los rodillos de trabajo. Un modelo matemático se desarrolló para predecir el perfil del entrehierro tomando en cuenta el gradiente térmico en el rodillo de trabajo y la distorsión producida por las fuerzas actuantes. Fue posible encontrar una buena correlación entre los perfiles de cintas obtenidos a partir de pruebas en planta y las predicciones del modelo. El modelo permite predecir el origen de defectos de forma a partir de cambios en el perfil de cintas laminadas.

  12. Tensile properties and conductivities of a precipitation hardened and cold-rolled Cu-0.3Cr-0.1Zr alloy at cryogenic temperature

    Science.gov (United States)

    Umezawa, O.

    2015-12-01

    Cu-0.3Cr-0.1Zr alloy (in mass%) is one of typical precipitation hardened copper- based alloys, and exhibited an excellent combination of high strength and high conductivities at the temperature range of 4 K to 300 K. The tensile properties, electrical resistivity, thermal conductivity and magnetization of precipitation hardened and cold-rolled Cu-0.3Cr-0.1Zr alloy were measures in comparison with oxygen free copper at cryogenic temperatures. The Cu- 0.3Cr-0.1Zr showed higher yield ratio (yield strength / tensile strength) and lower the ratio of yield strength to electrical resistivity at cryogenic temperature than oxygen free copper. It exhibited high electrical and thermal conductivities, excellent non-magnetic stability and very low magnetic permeability at 4.2 K.

  13. Microstructure and Mechanical Properties of V-Nb Microalloyed Ultrafine-Grained Dual-Phase Steels Processed Through Severe Cold Rolling and Intercritical Annealing

    Science.gov (United States)

    Papa Rao, M.; Subramanya Sarma, V.; Sankaran, S.

    2016-12-01

    Ultrafine-grained (UFG) dual-phase (DP) steel was produced by severe cold rolling (true strain of 2.4) and intercritical annealing of a low carbon V-Nb microalloyed steel in a temperature range of 1003 K to 1033 K (730 °C to 760 °C) for 2 minutes, and water quenching. The microstructure of UFG DP steels consisted of polygonal ferrite matrix with homogeneously distributed martensite islands (both of size hardening. Analysis of work hardening behavior of the UFG DP steels through modified Crussard-Jaoul analysis showed a continuously varying work hardening rate response which could be approximated by 2 or 3 linear regimes. The transmission electron microscopy analysis on post tensile-tested samples indicated that these regimes are possibly related to the work hardening of ferrite, lath, and twin martensite, respectively.

  14. 消除冷轧带钢停车斑的措施%Measures to Eliminate Stop Marks on the Cold-rolled Strip

    Institute of Scientific and Technical Information of China (English)

    周欣; 黄帼

    2011-01-01

    The stop mark is a quality defect in the hot strip rolling. This article analyzes the causes of stop marks and puts forward a modification solution of installing a reversing system to eliminate stop marks in the pickling and cold roiling line, which will solve the product quality problem that is difficult to handle in the production line for a long time.%针对热轧带钢停车斑的质量缺陷,分析了停车斑产生的原因,提出了新增倒车系统消除停车斑的改造方案,解决了酸轧联合机组长期难以解决的产品质量问题。

  15. Simulating AGC Hydraulic System of Single-stand Cold Rolling Mill%单机架冷轧机 AGC 液压系统仿真

    Institute of Scientific and Technical Information of China (English)

    吴中友; 陈举庆

    2013-01-01

    Hopsan Hydraulic Simulation software is used to model and simulate AGC hydraulic system of a 1250mm single-stand cold rolling mill to compare the difference and connection between the position loop and force loop of the control system. With this simulation, the factor that effects the function of AGC hydraulic systems can be analyzed.%  采用 Hopsan 液压仿真软件对某1250 mm 单机架可逆冷轧机 AGC 液压系统建模仿真,比较位置环与力环控制系统的差异和联系,对影响 AGC 液压系统性能的因素进行分析。

  16. Recovery of Ductility in Ultrafine-Grained Low-Carbon Steel Processed Through Equal-Channel Angular Pressing Followed by Cold Rolling and Flash Annealing

    Science.gov (United States)

    Singh, Raj Bahadur; Mukhopadhyay, N. K.; Sastry, G. V. S.; Manna, R.

    2017-01-01

    The low-carbon steel workpieces are deformed by equal-channel angular pressing at 293 K (20 °C) up to an equivalent strain of 12 using route B c, which results in the bulk ultrafine-grained (UFG) structure with high dislocation density and partial dissolution of cementite. The yield strength (YS) is enhanced from 208 (as-received) to 872 MPa and the tensile strength is increased from 362 to 996 MPa, but the material loses total elongation (TE) from 36.2 to 2.9 pct. Cold rolling of equal-channel angular pressed steel produces the refined structure of grain size 0.11 μm. The YS increases further to 924 MPa with a marginal gain in ductility due to the reappearance of the γ fiber component. Flash annealing the samples, which were equal-channel angular pressed followed by cold rolling, at 873 K (600 °C) results in 27 pct of micron-sized (9 µm) ferrite grains in submicron-sized (<1 µm) matrix with a reduced defect density and small amount of precipitation of cementite. TE increases from 2.9 to 23.3 pct. The material retains a YS of 484 MPa and tensile strength of 517 MPa, which are higher than those of the as-received material. The UFG grains are failed by cleavage, but the micron-sized grains display ductile fracture. The ductility of the flash-annealed material is recovered significantly due to bimodal grain size distribution in ferrite and the development of a good amount of γ fiber texture components. The major contribution toward recovery of ductility comes from the bimodal grain size distribution in ferrite rather the precipitation of cementite.

  17. The critical parameters in in-situ MgB2 wires and tapes with ex-situ MgB2 barrier after hot isostatic pressure, cold drawing, cold rolling and doping

    Science.gov (United States)

    Gajda, D.; Morawski, A.; Zaleski, A. J.; Häßler, W.; Nenkov, K.; Rindfleisch, M. A.; Żuchowska, E.; Gajda, G.; Czujko, T.; Cetner, T.; Hossain, M. S. A.

    2015-05-01

    MgB2 precursor wires were prepared using powder in tube technique by Institute of High Pressure PAS in Warsaw. All samples were annealed under isostatic pressure generated by liquid Argon in the range from 0.3 GPa to 1 GPa. In this paper, we show the effects of different processing routes, namely, cold drawing (CD), cold rolling (CR), hot isostatic pressure (HIP) and doping on critical current density (Jc), pinning force (Fp), irreversible magnetic-field (Birr), critical temperature (Tc), n value, and dominant pinning mechanism in MgB2/Fe wires with ex situ MgB2 barrier. The results show that medium pressures (˜0.35 GPa) lead to high Jc in low and medium magnetic fields (0 T - 9 T). On the other hand, higher pressures (˜1 GPa) lead to enhanced Jc in high magnetic fields (above 9 T). Transport measurements show that CD, CR, and HIP have small effects on Birr and Tc, but CD, CR, HIP, and doping enhance Jc and Fp in in situ MgB2 wires with ex situ MgB2 barrier. Transport measurements on in situ undoped MgB2 wire with ex situ MgB2 barrier yield a Jc of about 100 A/mm2 at 4.2 K in 6 T, at 10 K in 4 T and at 20 K in 2 T. The results also show that cold drawing causes increase of n value.

  18. Evolution of the Radial Abundance Gradient and Cold Gas of the Galactic Disk

    Science.gov (United States)

    Qi-Shi, Chen; Rui-Xiang, Chang; Jun, Yin

    2014-10-01

    In order to understand the forming mechanism of the radial abun- dance gradient of the Galactic disk and the evolution of cold gas, we have con- structed a chemical evolution model of the Galactic disk, in which the star for- mation law concerned with molecular hydrogens is adopted, and the evolution of mass surface density is calculated for the molecular and atomic hydrogens separately, then the model predictions and the observed radial distributions of some physical quantities are compared. The result indicates that the model prediction is sensitive to the adopted infall timescale, the model which adopts the star formation law concerned with the molecular hydrogens can agree well with the major observed properties of the Galactic disk, especially can obtain naturally the radial oxygen abundance gradient of the Galactic disk, and the radial surface density profile of cold gas. The assumption of instantaneous or non-instantaneous recycling approximation has a small effect on the evolution of cold gas, especially in the case of rather low gas density.

  19. Analysis on competitiveness and developing strategy of JISCO cold rolled sheet%酒钢冷轧薄板竞争力分析与发展战略简析

    Institute of Scientific and Technical Information of China (English)

    赵小龙; 常崇明

    2016-01-01

    The internal and external environment of JISCO cold rolled carbon steel was analyzed in-depth by making use of the SWOT matrix model combined with the practice of JISCO cold rolled sheet.The advantages,disadvanta-ges,opportunities and threats of cold rolled sheet market were described in details.The competitiveness of JISCO was analyzed and the growth type development strategy of cold rolled carbon steel was put forward.The good oper-ating results were achieved through the positive development and improvement of the enterprise competitiveness.%从 SWOT 矩阵模型理论出发,结合酒钢冷轧薄板实际,对冷轧薄板内部和外部环境进行了深入分析,阐明了酒钢冷轧薄板的优势、劣势、机会和威胁,对企业竞争力做了简析,并提出了酒钢冷轧薄板应采用增长型发展战略,通过积极发展与增长提高企业竞争力,取得了良好的效果。

  20. 冷轧含油废水处理技术及工艺现状%Treatment process and technological status of oil-bearing wastewater from cold rolling

    Institute of Scientific and Technical Information of China (English)

    曲余玲; 毛艳丽; 张东丽; 王涿

    2012-01-01

    冷轧含油废水的处理,对于钢铁企业减少污水排放量和新水用量、提高废水循环利用率具有重要的意义.介绍了国内外常用的冷轧含油废水处理技术,如重力分离法、气浮法、絮凝法、吸附法、膜分离法、生物法、膜生物反应器等,描述了冷轧含油废水处理工艺与现状,展望了冷轧含油废水处理的发展趋势.%For iron and steel enterprises,the treatment of oil-bearing wastewater from cold rolling has great significance to reducing the amount of effluent discharge and the dosage of fresh water needed, and improving the cyclic utilization water of wastewater- The commonly used treatment technologies of oil-bearing wastewater from cold rolling in China and abroad, such as gravity separation, air flotation, flocculation, adsorption, membrane separation, biological method and membrane bioreactors are introduced. In addition, the treatment process and present status of oil-bearing wastewater from cold rolling are described. Furthermore, the developing trend of oil-bearing wastewater from cold rolling is forecast.

  1. 冷带轧机液压AGC系统过程优化级计算机控制%Research on Computer Control of Process Optimization Level in Hydraulic AGC System of Cold Rolling Mill

    Institute of Scientific and Technical Information of China (English)

    孙孟辉; 王益群

    2015-01-01

    冷带轧机的轧制过程是较为复杂的物理过程,因此液压AGC(Automatic Gauge Control)系统对冷带轧机成品带钢的厚度精度起着重要的作用。针对300可逆冷带轧机,进行了过程优化级计算机控制的研究,开发出了液压AGC系统的过程优化级计算机控制系统。液压AGC系统的过程优化级计算机控制,可以实现轧制规程的计算、过程控制级所需设定值的设定、轧制过程数据的采集以及人机界面的显示等功能。同时,进行了轧制试验。%Rolling process of the cold rolling mill is a complicated physical process, so the hydraulic AGC system is very important to the thickness precision of strips of cold rolling mill. In this paper, the computer control of process optimization level was researched, and the computer control system of process optimization level was developed, aiming at 300 reverse cold rolling mill. By the computer control of process optimization level of the hydraulic AGC, it can realize the calculation of rolling schedule, the set of setting value needed by the process control level, the data acquisition of rolling process and the display of human-computer interface. At the same time, the rolling experiment was carried out, and the experiment result implied that it could eliminate the thickness error of strips effectively, adopting the provided computer control's strategy of the process optimization level.

  2. Evolution of CO2 and H2O on Mars: A cold Early History?

    Science.gov (United States)

    Niles, P. B.; Michalski, J.

    2011-01-01

    The martian climate has long been thought to have evolved substantially through history from a warm and wet period to the current cold and dry conditions on the martian surface. This view has been challenged based primarily on evidence that the early Sun had a substantially reduced luminosity and that a greenhouse atmosphere would be difficult to sustain on Mars for long periods of time. In addition, the evidence for a warm, wet period of martian history is far from conclusive with many of the salient features capable of being explained by an early cold climate. An important test of the warm, wet early Mars hypothesis is the abundance of carbonates in the crust [1]. Recent high precision isotopic measurements of the martian atmosphere and discoveries of carbonates on the martian surface provide new constraints on the evolution of the martian atmosphere. This work seeks to apply these constraints to test the feasibility of the cold early scenario

  3. DEFECTS SIMULATION OF ROLLING STRIP

    Directory of Open Access Journals (Sweden)

    Rudolf Mišičko

    2009-06-01

    Full Text Available The defects in the continuous casting slabs can be developed or kept down in principle by rolling technology, especially depend to sort, size and distribution of primary defects, as well as used of rolling parameters. Scope of the article is on observation behavior artificial surface and undersurface defects (scores without filler (surface defects and filling by oxides and casting powder (subsurface defects. First phase of hot rolling process have been done by software simulation DEFORM 3D setting to the limited condition for samples with surface defects. Samples of material with low-carbon steel of sizes h x b x l have been chosen and the surface defects shape „U” and „V” of scores have been injected artificially by software. The process of rolling have been simulated on the deformation temperatures 1200°C and 900°C, whereas on the both of this deformation temperatures have been applied amount of deformation 10 and 50 %. With respect to the process of computer simulation, it is not possible to truthful real oxidation condition (physical – chemical process during heat of metal, in the second phase of our investigation have been observed influence of oxides and casting powders inside the scores for a defect behavior in plastic deformation process (hot and cold rolling process in laboratory condition. The basic material was STN steel class 11 375, cladding material was steel on the bases C-Mn-Nb-V. Scores have been filled by scales to get from the heating temperatures (1100°C a 1250°C, varied types of casting powders, if you like mixture of scale and casting powders in the rate 1:4. The joint of the basic and cladding material have been done by peripheral welded joint. Experiment results from both phases are pointed on the evolution of original typology defects in rolling process.

  4. Functional evolution of leptin of Ochotona curzoniae in adaptive thermogenesis driven by cold environmental stress.

    Directory of Open Access Journals (Sweden)

    Jie Yang

    Full Text Available BACKGROUND: Environmental stress can accelerate the directional selection and evolutionary rate of specific stress-response proteins to bring about new or altered functions, enhancing an organism's fitness to challenging environments. Plateau pika (Ochotona curzoniae, an endemic and keystone species on Qinghai-Tibetan Plateau, is a high hypoxia and low temperature tolerant mammal with high resting metabolic rate and non-shivering thermogenesis to cope in this harsh plateau environment. Leptin is a key hormone related to how these animals regulate energy homeostasis. Previous molecular evolutionary analysis helped to generate the hypothesis that adaptive evolution of plateau pika leptin may be driven by cold stress. METHODOLOGY/PRINCIPAL FINDINGS: To test the hypothesis, recombinant pika leptin was first purified. The thermogenic characteristics of C57BL/6J mice injected with pika leptin under warm (23±1°C and cold (5±1°C acclimation is investigated. Expression levels of genes regulating adaptive thermogenesis in brown adipose tissue and the hypothalamus are compared between pika leptin and human leptin treatment, suggesting that pika leptin has adaptively and functionally evolved. Our results show that pika leptin regulates energy homeostasis via reduced food intake and increased energy expenditure under both warm and cold conditions. Compared with human leptin, pika leptin demonstrates a superior induced capacity for adaptive thermogenesis, which is reflected in a more enhanced β-oxidation, mitochondrial biogenesis and heat production. Moreover, leptin treatment combined with cold stimulation has a significant synergistic effect on adaptive thermogenesis, more so than is observed with a single cold exposure or single leptin treatment. CONCLUSIONS/SIGNIFICANCE: These findings support the hypothesis that cold stress has driven the functional evolution of plateau pika leptin as an ecological adaptation to the Qinghai-Tibetan Plateau.

  5. Functional Evolution of Leptin of Ochotona curzoniae in Adaptive Thermogenesis Driven by Cold Environmental Stress

    Science.gov (United States)

    Yang, Jie; Bromage, Timothy G.; Zhao, Qian; Xu, Bao Hong; Gao, Wei Li; Tian, Hui Fang; Tang, Hui Jun; Liu, Dian Wu; Zhao, Xin Quan

    2011-01-01

    Background Environmental stress can accelerate the directional selection and evolutionary rate of specific stress-response proteins to bring about new or altered functions, enhancing an organism's fitness to challenging environments. Plateau pika (Ochotona curzoniae), an endemic and keystone species on Qinghai-Tibetan Plateau, is a high hypoxia and low temperature tolerant mammal with high resting metabolic rate and non-shivering thermogenesis to cope in this harsh plateau environment. Leptin is a key hormone related to how these animals regulate energy homeostasis. Previous molecular evolutionary analysis helped to generate the hypothesis that adaptive evolution of plateau pika leptin may be driven by cold stress. Methodology/Principal Findings To test the hypothesis, recombinant pika leptin was first purified. The thermogenic characteristics of C57BL/6J mice injected with pika leptin under warm (23±1°C) and cold (5±1°C) acclimation is investigated. Expression levels of genes regulating adaptive thermogenesis in brown adipose tissue and the hypothalamus are compared between pika leptin and human leptin treatment, suggesting that pika leptin has adaptively and functionally evolved. Our results show that pika leptin regulates energy homeostasis via reduced food intake and increased energy expenditure under both warm and cold conditions. Compared with human leptin, pika leptin demonstrates a superior induced capacity for adaptive thermogenesis, which is reflected in a more enhanced β-oxidation, mitochondrial biogenesis and heat production. Moreover, leptin treatment combined with cold stimulation has a significant synergistic effect on adaptive thermogenesis, more so than is observed with a single cold exposure or single leptin treatment. Conclusions/Significance These findings support the hypothesis that cold stress has driven the functional evolution of plateau pika leptin as an ecological adaptation to the Qinghai-Tibetan Plateau. PMID:21698227

  6. 卡罗赛尔卷取机在冷轧生产线中的控制及应用%Carrousel Coiler in the Application of Cold Rolling Production Line

    Institute of Scientific and Technical Information of China (English)

    季宝伟; 吕金; 周先杰; 刘洋; 黄颖

    2011-01-01

    Cold-rolled strip steel produccion process is an important part of the coiling machine which is the kcy equipment of cold-rolled production With the rapid development of economic construction, especially the urgeni need of the metallurgical inclusiry the development for new or modificd fast growing number of strip cold rolling mill. Carrousel coiler with its high-speed two-drum winder, continuous strip winding way, has become a cold rolling strip production line, in particular, the whole production line of continuous cold- rolled strip winding deviee of choice. The device has compau design.can save installation space and equipmem inveslment.%冷轧是带钢生产工序中的重要组成部分,而卷取机是冷轧生产中的关键设备.随着经济建设的迅速发展,尤其是冶金工业发展的迫切需要,新上或改造的高速带钢冷连轧机日益增多,卡罗赛尔双卷筒卷取机以其高速、连续的带钢卷取方式,已成为带钢冷连轧生产线,尤其是全连续的冷轧带钢生产线的首选卷取设备.该设备结构设计紧凑,可节省设备安装空间,节省设备投资.

  7. Aging Behaviour of Al-Mg-Si Alloys Subjected to Severe Plastic Deformation by ECAP and Cold Asymmetric Rolling

    Directory of Open Access Journals (Sweden)

    S. Farè

    2011-01-01

    Full Text Available A study was carried out on aging behaviour of a 6082 alloy processed by two different severe plastic deformation techniques: ECAP and asymmetric rolling. Both techniques were able to generate an ultrafine-grained structure in samples processed at room temperature. It was stated that severe straining promotes marked changes in the postdeformation aging kinetics. The peaks of β′′/β′ transition phases were anticipated and of progressively reduced intensity over the coarse grained alloy. A further peak accounting for onset of recrystallization also appeared in the most severely deformed samples. Full consistency in peak shape and position was found when comparing materials processed by ECAP and asymmetric rolling. Isothermal aging treatments performed at 180°C revealed that in the severely deformed samples, aging became so fast that the hardness curves continuously decreased due to overwhelming effects of structure restoration. On the contrary, aging at 130°C offers good opportunities for fully exploiting the precipitate hardening effects in the ultrafine-grained alloy.

  8. Research of Asymmetrical Cold Rolling and Recrystallization Annealing Experiment of Flange Plate Steel%翼缘板钢非对称冷轧及再结晶退火实验研究

    Institute of Scientific and Technical Information of China (English)

    唐荻; 戴辉; 孙蓟泉

    2011-01-01

    对翼缘板钢采用非对称冷轧,在压下率78%时,对轧件进行微观显微组织观察,结果表明:随着异速比增大,晶粒长度和宽度比值也增大;提出了在异步轧制条件下,晶粒长宽比值可以反映轧件所受附加剪切变形的大小.对冷轧后的轧件进行拉伸实验与不同温度的退火实验,并进行透射电镜观察,结果表明:随着异速比增加,规定非比例延伸强度增加,退火后晶粒平均直径变小;同时,观察到了较高位错密度的位错和较小尺寸的亚晶;由此验证了异步轧制可比同步轧制产生更多的附加剪切变形以及更多的位错和亚晶,可以提高翼缘板钢的强度,增加应变储能,降低再结晶退火温度.%Asymmetrical cold rolling technology was adopted for flange plate steel. Microstructure of rolled pieces was observed under the accumulated reduction of 78%. The results show that as the ratio of working rollers' speed is greater, the ratio of length to width of gain is higher. The idea is put forward that the ratio of length to width of gain can reflect the additional shear deformation size of rolled pieces under the condition of asymmetrical rolling. The tensile tests and annealing tests at different annealing temperatures were made for cold rolled pieces and the microstructure was observed by the transmission electron microscopy. The results show that as the ratio of working rollers' speed is greater, proof strength increases, average grain diameter decreases after cold rolled pieces annealed. With increase of the ratio of working rollers' speed, high density dislocations and the small size subgrains are observed. It indicates that asymmetrical rolling can present more additional shear strain than that of symmetrical rolling, more dislocations and subgrains can be generated in the course of asymmetrical rolling, and the strength of the flange plate steel is enhanced and the straining accumulation energy increases under the condition of

  9. FORMATION OF SHAFT SPLINES USING ROLLING METHOD

    Directory of Open Access Journals (Sweden)

    M. Sidorenko

    2012-01-01

    Full Text Available The paper describes design of rolling heads used for cold rolling of straight-sided splines on shafts and presents theoretical principles of this process. These principles make it possible to calculate an effort which is required for pushing billet through rolling-on rolls with due account of metal hardening during deformation.

  10. Prediction for Edge Cracking for Silicon Steel Sheet with Edge Defect during Cold Rolling Based on GTN Damage Model%基于GTN损伤模型对含边部缺陷硅钢薄板冷轧时边裂的预测

    Institute of Scientific and Technical Information of China (English)

    孙权; 闫玉曦; 陈建钧; 潘红良

    2013-01-01

    采用拉伸试验和显微组织观测的方法确定了GTN损伤模型中的9个损伤参数,运用GTN损伤模型对冷轧硅钢薄板边部缺陷的扩展及边裂的产生进行了有限元模拟,并与预置缺口的钢板轧制试验进行对比.结果表明:轧制过程中边部缺陷是造成钢板边部裂纹萌生和扩展的一个重要原因,GTN损伤模型可用来预测含边部缺陷硅钢薄板在冷轧过程中边裂的产生;预测结果与试验结果基本一致.%The crack initiation and propagation of silicon steel strip with edge defect during cold rolling process was studied by using GTN damage model in this paper. Nine damage parameters in GTN model were identified by tensile testing and microstructure observing, and then the FE simulation of edge defect evolution of silicon steel strip during rolling process was conducted on the base of GTN damage model, and then the results were compared with rolling experimental results. The results show that the edge defect was a important reason for edge-crack initiation and propagation, and GTN damage model could be used to predict the occurrence of edge-crack of steel strip with edge defect during cold rolling process. The predicted results matched the experimental ones.

  11. The influence of heat treatment on properties of cold rolled alloyed steel and nickel superalloys sheets used in aircraft industry

    Science.gov (United States)

    Zaba, K.; Dul, I.; Puchlerska, S.

    2017-02-01

    Superalloys based on nickel and selected steels are widely used in the aerospace industry, because of their excellent mechanical properties, heat resistance and creep resistance. Metal sheets of these materials are plastically deformed and applied, inter alia, to critical components of aircraft engines. Due to their chemical composition these materials are hardly deformable. There are various methods to improve the formability of these materials, including plastic deformation at an elevated or high temperature, or a suitable heat treatment before forming process. The paper presents results of the metal sheets testing after heat treatment. For the research, sheets of two types of nickel superalloys type Inconel and of three types of steel were chosen. The materials were subjected to multivariate heat treatment at different temperature range and time. After this step, mechanical properties were examined according to the metal sheet rolling direction. The results were compared and the optimal type of pre-trial softening heat treatment for each of the materials was determined.

  12. Evolution of magnetism by rolling up hexagonal boron nitride nanosheets tailored with superparamagnetic nanoparticles.

    Science.gov (United States)

    Hwang, Da Young; Choi, Kyoung Hwan; Park, Jeong Eon; Suh, Dong Hack

    2017-02-01

    Controlling tunable properties by rolling up two dimensional nanomaterials is an exciting avenue for tailoring the electronic and magnetic properties of materials at the nanoscale. We demonstrate the tailoring of a magnetic nanocomposite through hybridization with magnetic nanomaterials using hexagonal boron nitride (h-BN) templates as an effective way to evolve magnetism for the first time. Boron nitride nanosheets exhibited their typical diamagnetism, but rolled-up boron nitride sheets (called nanoscrolls) clearly have para-magnetism in the case of magnetic susceptibility. Additionally, the Fe3O4 NP sample shows a maximum ZFC curve at about 103 K, which indicates well dispersed superparamagnetic nanoparticles. The ZFC curve for the h-BN-Fe3O4 NP scrolls exhibited an apparent rounded maximum blocking temperature at 192 K compared to the Fe3O4 NPs, leading to a dramatic increase in TB. These magnetic nanoscroll derivatives are remarkable materials and should be suitable for high-performance composites and nano-, medical- and electromechanical-devices.

  13. 择优蚀坑表征立方晶系冷轧电工硅钢取向性%Grain orientation characterization of cold-rolled electrical steel sheets in the cubic crystal system by etch figures

    Institute of Scientific and Technical Information of China (English)

    李岩; 董秀文; 于志伟; 孔平

    2016-01-01

    In order to determine the value of import, the tax collecting and perform different ways of supervision regulations according to the grain orientation characterization of the electrical steel sheets, the etch figures of cold-rolled electrical steel sheets based on the preferential etch behavior were investigated by means of etch figure method. The relationships between the etch figures and grain orientation were analyzed from the viewpoint of crystallography. The results show that the geometric morphology of the etch figures on the rolling surface is disordered orientation for the non-oriented electrical steel sheets, and their corresponding miller indexes are (001), (011) and (111), respectively, and other miller indexes by their evolution formation. On the rolling surface of the grain-oriented electrical steel sheets, the etch figures are regular geometric morphology, miller index is (011), or other miller indexes by the evolution formation. The morphology of etch figures on the grain boundary related to the orientation difference between the adjacent grain, big orientation difference, will form{100},{110}and{111}crystal system of etch figures, whereas if small, will form{110}crystal system of etch figures. For grain-oriented steel sheets, the geometric morphology of etch figures is not affected by the grain boundary. The basal edges of the etch figures are parallel each other, and the deviation angle is less than 5 degrees. Their basal edges, extending direction are same as the rolling direction of the steel sheets, and the deviation angle shall not exceed 5 degrees also.%为确定电工硅钢的晶粒取向性,应用蚀坑技术研究了冷轧无取向硅钢、取向硅钢因择优腐蚀所形成的蚀坑与晶粒取向的关系,分析了{100}面系蚀坑形貌的演变过程,从晶体学角度建立了蚀坑形貌与晶面指数的对应关系.结果发现:无取向硅钢形成不同形貌的蚀坑,其晶面指数为( 001)、( 011)和( 111) ,或是由它们

  14. Simulative computation of rolling force in cold pilgering process of high-accuracy stainless steel pipe%高精度不锈钢管轧制过程轧制力仿真计算

    Institute of Scientific and Technical Information of China (English)

    成海宝; 赵铁勇; 郝瑾; 纪松山; 展京乐; 张杰

    2012-01-01

    针对钢管冷轧过程轧制力的影响因素多、计算复杂的问题,本文以舍瓦金提出的轧制力计算方法为依据,利用Fortran语言开发了轧制力计算模拟程序,该程序可用来分析送进量、压下量、孔型参数等对轧制力分布的影响.并以轧制奥氏体不锈钢管1Cr18Ni9Ti为例,研究了送进量和管坯厚度对轧制力分布的影响.%Since there are lots of factors which affect the rolling force in the steel pipe cold-rolling processes, and the calculation process of the rolling force is complex, a simulation program for rolling force calculation was developed with Fortran language, according to Shevakii proposed calculation method. The program can be used to analyze the influence of feeding quantity, reduction and die parameters on rolling force distribution. Finally, taking the austenitic stainless steel lCrl8Ni9Ti as example, the influence of feeding and hollow thickness on the rolling force distribution is studyed.

  15. Cold adaptation of a mesophilic cellulase, EG III from Trichoderma reesei, by directed evolution

    Institute of Scientific and Technical Information of China (English)

    XIAO; Zhizhuang(肖志壮); WANG; Pan(王攀); QU; Yinbo(曲音波); GAO; Peiji(高培基); WANG; Tianhong(汪天虹)

    2002-01-01

    Cold-active enzymes have received little research attention although they are very useful in industries. Since the structure bases of cold adaptation of enzymes are still unclear, it is also very difficult to obtain cold-adapted enzymes for industrial applications using routine protein engineering methods. In this work, we employed directed evolution method to randomly mutate a mesophilic cellulase, endoglucanase III (EG III) from Trichoderma reesei, and obtained a cold- adapted mutant, designated as w-3. DNA sequence analysis indicates that w-3 is a truncated form of native EG III with a deletion of 25 consecutive amino acids at C-terminus. Further examination of enzymatic kinetics and thermal stability shows that mutant w-3 has a higher Kcat value and becomes more thermolabile than its parent. In addition, activation energies of w-3 and wild type EG III calculated from Arrhenius equation are 13.3 kJ@mol-1 and 26.2 kJ@mol-1, respectively. Therefore, the increased specific activity of w-3 at lower temperatures could result from increased Kcat value and decreased activation energy.

  16. Microstructural evolution of as-rolled modified 9Cr-1Mo steel during friction stir welding

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung-Gu; Lee, Min-Ku; Rhee, Chang-Kyu; Kim, Tae-Kyu [Korea Atomic Energy Research Institute (KAERI), Daejeon (Korea, Republic of). Nuclear Materials Development Div.; Kim, Ju-Myoung [Nano Technology Inc., Daejeon (Korea, Republic of). R and D Center

    2013-09-15

    Friction stir welding was tried on a modified 9Cr-1Mo (wt.%) ferritic steel in an as-rolled condition. The microstructure of the resultant weld was divided into four distinct regions according to each thermo-mechanical history experienced during welding; i.e., stir zone, thermo-mechanically affected zone, inner heat-affected zone, and outer heat-affected zone. The first three zones showed distinct martensite morphologies depending on the different recrystallization phenomena during the heating cycle in the single-phase austenite region. In the outer heat-affected zone, however, only tempering occurred without phase transformation owing to a relatively low heating temperature. Hardness distribution of the weld closely reflected such microstructural differences, indicating that a considerable softening occurred in the thermo-mechanically affected zone and outer heat-affected zone owing to the coarsening and tempering effects, respectively. (orig.)

  17. Study on cold rolling oil for sheet steel based on rapeseed oil%植物油基薄钢板冷轧轧制油的研究

    Institute of Scientific and Technical Information of China (English)

    刘佳; 杨基和; 刘英杰

    2012-01-01

    植物油由于其优良的润滑性、退火清净性、离水展着性和可生物降解性,成为冷轧轧制油基础油研究的趋势.以菜籽油为基础油,通过添加23.72%高黏植物油、1.34%极压抗磨剂、1.02%脂肪酸、4.88%抗氧剂、11%乳化剂和2.7%消泡剂,开发出一种高黏度,抗氧性、极压抗磨性、低温流动性和乳化效果好的薄钢板冷轧轧制油,其母油性能完全达到奎克公司同类产品标准,乳液性能满足我国行业使用标准.使用植物油开发绿色冷轧轧制油,是实现可持续发展,解决石油危机的有效途径.%Because of good properties of lubrication,anneal free of annoyance,plate -out ability and biodegradable ability,the vegetable oils used as the base oil of lubricants was studied by many researchers. A cold rolling oil for steel sheet which showed high viscosity, good oxidation resistance, extreme pressure abrasion resistance,low temperature fluidity and emulsifying effect was developed by adding 23.72% high viscosity oil, 1.34% extreme pressure anti -wear additive, 1.02% fatty acid,4. 88% antioxidants, 11 % emulsifier and 2. 7% defoamer,using rapeseed oil as base oil. The mother oil performance could fully meet the Quaker products standard, and the emulsion performance could satisfy industry standard. It is an effective way using vegetable oil to develop green cold rolling oil to achieve sustainable development and solve petroleum oil crisis.

  18. Analysis of the factors affecting thermal evolution of hot rolled steel during coil cooling

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The thermal evolution of steel coil during cooling was simulated and investigated by the use of in-house Q-CSP(R) software.The dependence of the thermal evolution of steel coil on cooling methods, temperature distribution of the strip before coiling, coil size and steel grades was also discussed.The study plays a significant role in helping steel makers to better understand and control the cooling process.

  19. Comparison of Inclusions in Cold Drawn Wire and Precursor Hot-Rolled Rod Coil in VIM-VAR Nickel-Titanium Alloy

    Science.gov (United States)

    Sczerzenie, Frank; Paul, Graeme; Belden, Clarence

    2011-07-01

    Inclusion content is important for the mechanical behavior and performance of Nitinol wires, particularly in fatigue-rated devices. The purpose of this work was to make a quantitative comparison between inclusion populations in cold drawn wires and the precursor populations in hot-rolled rod coil. Inclusion content was examined in a series of VIM-VAR alloys with different transformation temperatures (TTR) controlled by the Ni to Ti ratio. This range of chemistry was chosen to assess the effect of Ni to Ti ratio on inclusion formation. In order to understand the differences in behavior between carbides and intermetallic oxides in wire drawing, carbides, and intermetallic oxide inclusions were measured separately using optical metallography pursuant to ASTM F2063. In VIM-VAR alloys at higher Ni to Ti ratios about 50.79 a/o Ni the formation of intermetallic oxides appears to be suppressed in the as-cast material through the presence of carbon and the precipitation of eutectic TiC in place of eutectic Ti4Ni2O x . The structure of VIM-VAR alloy also varies after hot working depending on the TTR of the alloy. Higher TTR binary alloys with lower Ni to Ti ratios tend to have more and larger intermetallic oxides and fewer and smaller carbides after hot working. Microsegregation plays a role in inclusion formation. That is, during solidification, C, O, N diffuse to the interdendritic regions. This increases the potential for the precipitation of nonmetallic species. Carbides and intermetallic oxides behave differently in hot working and cold drawing. The change in maximum carbide size from coil to wire is very near zero for all Ni to Ti ratios. The change in maximum inclusion size from coil to wire is driven mainly by the fracture of intermetallic oxides and the formation of intermetallic oxide stringers.

  20. 考虑层问作用的冷轧钢卷抗凹性分析%Dent Resistance Analysis of Cold Rolled Steel Coil Considering Interlayer Effect

    Institute of Scientific and Technical Information of China (English)

    刘海江; 郭瑞玲

    2012-01-01

    针对冷轧钢卷包装中多层材料的接触变形问题,对钢卷包装系统的抗凹性进行了分析与研究;建立了考虑层间作用的钢卷包装系统的力学模型,计算和分析了钢卷的变形和应力,应用HYPERMESH与ANSYS/LS-DYNA对钢卷抗凹性模型进行了有限元仿真;最后进行了抗凹性模型的冲击试验,验证了有限元仿真计算结果,可为钢卷包装工艺设计提供理论依据。%For solving the multi-layer contact deformation problem of cold rolled steel coil, dent resistance of steel coil packaging system was analyzed and studied. Mechanical model of steel coil packaging system considering interlayer effect was established and the strain and stress of the steel colt was calculated and analyzed. FEM simulation of dent resistance of the steel coil was carried out by using HYPERMESH and ANSYS/LS-DYNA. An impact test of the dent resistance model was carried out to verify the FEM simulation. The purpose was to provide theory basis for steel coil packaging process design.

  1. The effects of cold rolling orientation and water chemistry on stress corrosion cracking behavior of 316L stainless steel in simulated PWR water environments

    Science.gov (United States)

    Chen, Junjie; Lu, Zhanpeng; Xiao, Qian; Ru, Xiangkun; Han, Guangdong; Chen, Zhen; Zhou, Bangxin; Shoji, Tetsuo

    2016-04-01

    Stress corrosion cracking behaviors of one-directionally cold rolled 316L stainless steel specimens in T-L and L-T orientations were investigated in hydrogenated and deaerated PWR primary water environments at 310 °C. Transgranular cracking was observed during the in situ pre-cracking procedure and the crack growth rate was almost not affected by the specimen orientation. Locally intergranular stress corrosion cracks were found on the fracture surfaces of specimens in the hydrogenated PWR water. Extensive intergranular stress corrosion cracks were found on the fracture surfaces of specimens in deaerated PWR water. More extensive cracks were found in specimen T-L orientation with a higher crack growth rate than that in the specimen L-T orientation with a lower crack growth rate. Crack branching phenomenon found in specimen L-T orientation in deaerated PWR water was synergistically affected by the applied stress direction as well as the preferential oxidation path along the elongated grain boundaries, and the latter was dominant.

  2. Efficient anti-corrosive coating of cold-rolled steel in a seawater environment using an oil-based graphene oxide ink.

    Science.gov (United States)

    Singhbabu, Y N; Sivakumar, B; Singh, J K; Bapari, H; Pramanick, A K; Sahu, Ranjan K

    2015-05-07

    We report the production of an efficient anti-corrosive coating of cold-rolled (CR) steel in a seawater environment (∼3.5 wt% NaCl aqueous solution) using an oil-based graphene oxide ink. The graphene oxide was produced by heating Aeschynomene aspera plant as a carbon source at 1600 °C in an argon atmosphere. The ink was prepared by cup-milling the mixture of graphene oxide and sunflower oil for 10 min. The coating of ink on the CR steel was made using the dip-coating method, followed by curing at 350 °C for 10 min in air atmosphere. The results of the potentiodynamic polarization show that the corrosion rate of bare CR steel decreases nearly 10,000-fold by the ink coating. Furthermore, the salt spray test results show that the red rusting in the ink-coated CR steel is initiated after 100 h, in contrast to 24 h and 6 h in the case of oil-coated and bare CR steel, respectively. The significant decrease in the corrosion rate by the ink-coating is discussed based on the impermeability of graphene oxide to the corrosive ions.

  3. Microstructure and Mechanical Properties of V-Nb Microalloyed Ultrafine-Grained Dual-Phase Steels Processed Through Severe Cold Rolling and Intercritical Annealing

    Science.gov (United States)

    Papa Rao, M.; Subramanya Sarma, V.; Sankaran, S.

    2017-03-01

    Ultrafine-grained (UFG) dual-phase (DP) steel was produced by severe cold rolling (true strain of 2.4) and intercritical annealing of a low carbon V-Nb microalloyed steel in a temperature range of 1003 K to 1033 K (730 °C to 760 °C) for 2 minutes, and water quenching. The microstructure of UFG DP steels consisted of polygonal ferrite matrix with homogeneously distributed martensite islands (both of size produced through intercritical annealing at 1013 K (740 °C) has good combination of strength (1295 MPa) and ductility (uniform elongation, 13 pct). The nanoscale V- and Nb-based carbides/carbonitrides and spheroidized cementite particles have played a crucial role in achieving UFG DP microstructure and in improving the strength and work hardening. Analysis of work hardening behavior of the UFG DP steels through modified Crussard-Jaoul analysis showed a continuously varying work hardening rate response which could be approximated by 2 or 3 linear regimes. The transmission electron microscopy analysis on post tensile-tested samples indicated that these regimes are possibly related to the work hardening of ferrite, lath, and twin martensite, respectively.

  4. Synergistic inhibition effect of 5-aminotetrazole and 4,6-dihydroxypyrimidine on the corrosion of cold rolled steel in H{sub 3}PO{sub 4} solution

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xianghong, E-mail: xianghong-li@163.com [Yunnan Key Laboratory of Wood Adhesives and Glue Products, Southwest Forestry University, Kunming 650224 (China); Faculty of Science, Southwest Forestry University, Kunming 650224 (China); Deng, Shuduan [Yunnan Key Laboratory of Wood Adhesives and Glue Products, Southwest Forestry University, Kunming 650224 (China); Xie, Xiaoguang [School of Chemical Science and Technology, Yunnan University, Kunming 650091 (China); Du, Guanben [Yunnan Key Laboratory of Wood Adhesives and Glue Products, Southwest Forestry University, Kunming 650224 (China)

    2016-09-15

    The synergistic inhibition effect of 5-aminotetrazole (AT) and 4,6-dihydroxypyrimidine (DHP) on the corrosion of cold rolled steel (CRS) in H{sub 3}PO{sub 4} solution was studied by weight loss, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), quantum chemical calculation and molecular dynamics (MD) methods. The results show that AT exhibits a moderate inhibitive effect, and DHP has a poor effect. However, incorporation AT with DHP significantly improves the inhibitive performance, and yields synergism. The adsorption of AT in the absence and presence of DHP obeys Langmuir adsorption isotherm. AT/DHP mixture acts as a mixed-type inhibitor. The combined AT and DHP molecules co-adsorb on the Fe (001) surface in the nearly flat manner, and the adsorption energy is larger than individual AT or DHP. - Highlights: • There is a synergistic inhibition effect of AT and DHP for steel in H{sub 3}PO{sub 4} solution. • The adsorption of AT whether it is mixed with DHP or not obeys Langmuir isotherm. • The AT/DHP mixture behaves as a mixed-type inhibitor. • E{sub HOMO} increases and E{sub LUMO} decreases in the combined AT and DHP. • AT and DHP co-adsorb on Fe (001) surface with the nearly flat manner.

  5. 冷轧钢板锈蚀原因及防锈对策%CORROSION AND PROTECTION OF COLD ROLLED STEEL PLATE IN HUMID ATMOSPHERE

    Institute of Scientific and Technical Information of China (English)

    李处森; 张学元; 杜元龙

    2001-01-01

    通过对冷轧钢板在高温、高湿大气环境中锈蚀原因进行系统分析,提出了利用油-气两相缓蚀的方案解决钢板表面防锈油涂覆不均造成的腐蚀问题.阐述了气相防锈油DZL的设计方案,通过静态湿热腐蚀试验和气相防锈性能试验评价了接触缓蚀和气相缓蚀性能,并用电化学方法对其气相缓蚀作用进行了研究.%By analyzing systematically the reasons of corrosion and rust of cold rolled steel plate in humid atmosphere, it is put forward to use both oil and vapor phase inhibition to solve the serious corrosion problem on the surface of steel plate caused by partially covered anti - rust oil. In the paper, the design of the vapor phase anti - rust oil DZL was elaborated, and the properties of touching inhibition and vapor phase inhibition were evaluated by corrosion test in humid atmosphere and by vapor phase anti - rust test. In addition, the vapor phase inhibition was also studied and clarified by electrochemical methods.

  6. Effect of heat treatment on formability in 0.15C-1.5Si-1.5Mn multiphase cold-rolled steel sheet

    Science.gov (United States)

    Lee, Chang Gil; Kim, Sung-Joon; Song, Byung-Hwan; Lee, Sunghak

    2002-10-01

    The effects of volume fraction and the stability of retained austenite on the formability of a 0.15C-1.5Si-1.5Mn (hereafter all in wt.%) TRIP-aided multiphase cold-rolled steel sheet were investigated after various heat treatments. The steel sheets were intercritically annealed at 800°C, and isothermally treated at 400°C and 430°C. Microstructural observation, tensile tests and limiting dome height (LDH) tests were conducted on the heat-treated sheet specimens, and the changes in retained austenite volume fraction as a function of tensile strain were measured using an X-ray diffractometer. The results showed a plausible relationship between formability and retained austenite stability. Although the same amount of retained austenite was obtained after isothermal holding at different temperatures, better formability was obtained in the specimens with the higher stability of retained austenite. If the stability of the retained austenite is high, the strain-induced transformation of retained austenite to martensite can be stably progressed, resulting in a delay of necking to the high strain region and improvement in formability.

  7. Effect of Annealing Temperature on the Microstructure, Tensile Properties, and Fracture Behavior of Cold-Rolled High-Mn Light-Weight Steels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Hyun; Cho, Kyung Mox [Pusan National University, Busan (Korea, Republic of); Park, Seong-Jun; Moon, Joonoh; Kang, Jun-Yun; Park, Jun-Young; Lee, Tae-Ho [Korea Institute of Materials Science, Changwon (Korea, Republic of)

    2017-05-15

    The effects of the annealing temperature on the microstructure and tensile properties of cold-rolled light-weight steels are investigated using two Fe-30Mn-xAl-0.9C alloys that contain different Al content. The initial alloy microstructure is composed of a single austenite or a mixture of austenite and ferrite depending on the nominal aluminum content. For the alloy with 9 wt%Al content, the recrystallization and grain growth of austenite occurrs depending on the annealing temperature. However, for the alloy with 11 wt%Al content, the β-Mn phase is observed after annealing for 10 min at 550~800 ℃. The β-Mn transformation kinetics is the fastest at 700 ℃. The formation of the β-Mn phase has a detrimental effect on the ductility, and this leads to significant decreases in the total elongation. The same alloy also forms κ-carbide and DO3 ordering at 550~900 ℃. The investigated alloys exhibit a fully recrystallized microstructure after annealing at 900 ℃ for 10 min, which results in a high total elongation of 25~55%with a high tensile strength of 900~1170 MPa.

  8. Evolution of large-scale structure in a universe dominated by cold dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.; Efstathiou, G.; Frenk, C.S.; White, S.D.M.

    1985-05-15

    We present the results of numerical simulations of nonlinear gravitational clustering in universe dominated by weakly interacting, ''cold'' dark matter (e.g., axions or photinos). These studies employ a high resolution N-body code with periodic boundary conditions and 32,768 particles; they can accurately represent the theoretical initial conditions over a factor of 16 in length scale. We have followed the evolution of ensembles of models with ..cap omega.. = 1 and ..cap omega.. < 1 from the initial conditions predicted for a ''constant curvature'' primordial fluctuation spectrum.

  9. Influence of cold-rolling on the precipitation processes in Cu-4 at. % Ti alloy; Influencia de la deformacion en frio sobre el proceso de precipitacion en una aleacion de Cu-4 at. % Ti

    Energy Technology Data Exchange (ETDEWEB)

    Donoso, E.

    2008-07-01

    By using differential scanning calorimetry (DSC), energetic and kinetic measurements associated with the different peaks displayed during linear heating of Cu-4 at. % Ti were made, employing quenched and cold-work material at different percentages of cold-rolling. Unlike to the situation observed in the quenched alloy in which precipitation is developed, in the deformed alloys such process is inhibited by the segregation of the solute atoms to partial dislocations. For calculating the dislocation density an expression governing the energy release accompanying recrystallization was applied, in order to determine, by appropriate models, the energy evolved during the pinning process. (Author) 35 refs.

  10. Research of optimization method for friction coefficient model in cold rolling process%冷轧轧制过程摩擦系数模型优化方法研究

    Institute of Scientific and Technical Information of China (English)

    高雷; 郭立伟; 李书昌; 陈丹; 何绪铃

    2014-01-01

    The friction coefficient model in cold rolling process is a nonlinear polynomial. In order to get the parameters of friction coefficient model which can better reflect the real rolling condition,we perform regression analysis on the parameters through optimized method by making full use of the ac-tual process data. The practical application proves that it can improve the calculation precision of the friction coefficient model in cold rolling process and provide a basis for high accuracy rolling.%冷轧轧制过程摩擦系数模型为非线性多项式,为了获得更能反应实际轧制工况的摩擦系数模型参数,充分利用实际工艺数据,通过优化的方法对模型参数进行回归分析。实际应用证明,该方法可以提高轧制过程摩擦系数模型设定精度,为高精度轧制提供基础。

  11. Effect of Delay Time on Microstructural Evolution during Warm Rolling of Ti-Nb-IF Steel

    Institute of Scientific and Technical Information of China (English)

    A.Najafi-zadeh; R.Ebrahimi

    2004-01-01

    The effect of delay time with constant first finishing pass temperature (800℃) has been investigated by means of multi-pass torsion tests on Ti-Nb-IF steel. All the tests have been carried out at a strain rate of 2 s-1 with 11 passes and 0.3 strain each pass. During the final pass, dynamic recrystallization occurs to a degree that depends on the delay time. In short interpass time (1 s) and at these temperatures (T≤800℃) there is not enough time to start static recrystallization, therefore, accumulation of strain occurs and after some passes, strain reaches a critical strain for starting dynamic recrystallization. In this study, the changes of mean flow stress during each pass and also the microstructural observation confirms that dynamic recrystallization occurs after some passes in ferrite phase of this steel. The stress-strain curves with constant temperature obtained by using a kinetic model and compensation of the increasing mean flow stress with decreasing temperature. Thus, this result also confirms that dynamic recrystallization occurs in warm rolling of this IF steel.

  12. Microstructural evolution and mechanical behaviour of surface hardened low carbon hot rolled steel

    Energy Technology Data Exchange (ETDEWEB)

    Tewary, N.K. [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur, Howrah 711103 (India); Syed, B. [R and D Division, Tata Steel Limited, Jamshedpur 831007 (India); Ghosh, S.K., E-mail: skghosh@metal.becs.ac.in [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur, Howrah 711103 (India); Kundu, S. [R and D Division, Tata Steel Limited, Jamshedpur 831007 (India); Shariff, S.M.; Padmanabham, G. [Centre for Laser Processing, ARCI-Hyderabad, Balapur PO, AP 500005 (India)

    2014-06-01

    Surface hardening of low carbon hot rolled C–Mn steel has been successfully performed by high power diode laser with an achievable case depth of about 300 μm. The laser treated samples have been characterised using optical microscope, scanning electron microscope, transmission electron microscope, and X-ray diffraction techniques. Higher hardness level is achieved in laser surface hardened zone (≈300 HV) than in the base alloy region (≈140 HV). The variation in hardness as a function of distance across the laser tracks is observed during multi-track laser hardening. Laser hardened steel sheets show enhanced mechanical strength (YS: 383–443 MPa, UTS: 476–506 MPa) with the lowering of percentage total elongation (23–28%) compared to the base alloy (YS: 351 MPa, UTS: 450 MPa and total elongation is 32%). Strain hardening exponent (‘n’) has been evaluated from true tensile stress–strain diagram and it shows a similar nature for both base alloy and laser treated steels. The microstructure in the base alloy region consists of a mixture of ferrite and pearlite, whereas predominantly lath martensite is present in the laser hardened surface layer. The improvement of mechanical strength is discussed in terms of the formation of this hardened layer on the surface.

  13. Effect of pre-heat treatments and cold rolling reduction on recrystallization texture of 6082 aluminum alloy%预处理和变形量对6082铝合金再结晶织构的影响

    Institute of Scientific and Technical Information of China (English)

    江海涛; 孙璐; 蔡正旭; 张成刚

    2013-01-01

    采用取向分布函数法分析并研究了冷轧前预处理和冷轧变形量对6082铝合金再结晶的影响.结果表明,6082铝合金的再结晶织构主要由立方织构和旋转立方织构组成.不经过热处理和经过固溶时效处理的试样,随着冷轧变形量的增加,再结晶织构组分明显增加;只经过固溶处理的试样,随着冷轧变形量的增加,再结晶织构组分变化不明显,说明冷轧前固溶处理可以明显弱化再结晶织构.%Effects of pre-heat treatments and cold rolling reduction on recrystallization texture of 6082 aluminum alloy were investigated by ODF (orientation distribution function).The results show that the recrystallization textures of 6082 aluminum alloy consist of cube texture and rotated cube texture components.For the samples without pre-heat treatment and overaging treatment,the recrystallization textures obviously increase with the increasing cold rolling reduction.However,the recrystallization textures change little with the increasing of cold rolling reduction for the solution-treated samples.The process of solution treatment before cold rolling can weaken the recrystallization texture of 6082 aluminum alloy.

  14. Development of electric control system of the large cold pipe rolling mill%大型冷轧管机组的电气控制系统研制

    Institute of Scientific and Technical Information of China (English)

    赵铁琳

    2015-01-01

    LG720 cold pipe rolling mill is the first large-scale cold pipe rolling mill in the world. The electric sys-tem applies PLC、variable frequency speed regulation (VFSR)、PROFIBUS-DP network、SIMOTION D and HMI technologies, which can realize the muti-motor VFSR drive, especially in large inertia load feed-in and rotation mechanism with high dynamic response, high precision positioning and synchronization control. This system fully meets the production requirements of the large-scale cold pipe rolling.%LG720冷轧管机组是世界最大规格冷轧管机组。为该机组研制的电气系统采用了PLC、变频调速、PROFIBUS-DP网络通讯、SIMOTION D、HMI等技术,实现了多机变频调速传动,对大惯量负载的送进和回转机构实现高动态响应、高精度定位和同步控制,满足了大型冷轧管机组的生产要求。

  15. Effect of cold deformation on the recrystallization behavior of FePd alloy at the ordering temperature using electron backscatter diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hung-Pin; Chen, Yen-Chun [Department of Materials Science and Engineering, National Cheng-Kung University, No. 1, University Road, Tainan 701, Taiwan (China); Chen, Delphic [Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, No. 70, Lienhai Road, Kaohsiung 80424, Taiwan (China); Research Center for Physical Properties and Microstructure of Metals, National Sun Yat-Sen University, No. 70, Lienhai Road, Kaohsiung 80424, Taiwan (China); Kuo, Jui-Chao, E-mail: jckuo@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng-Kung University, No. 1, University Road, Tainan 701, Taiwan (China)

    2014-08-15

    In this study, the evolution of the recrystallization texture and microstructure was investigated after annealing of 50% and 90% cold-rolled FePd alloy at 530 °C. The FePd alloy was produced by vacuum arc melting in an atmosphere of 97% Ar and 3% H{sub 2}. The specimens were cold rolled to achieve 50% and 90% reduction in thickness. Electron backscatter diffraction measurements were performed on the rolling direction–normal direction section. With increased deformation from 50% to 90%, recrystallized texture transition occurs. For the 50% cold-rolled alloy, the preferred orientation is (0 1 0) [11 0 1], which is close to the cubic orientation after 400 h of annealing. For the 90% cold-rolled alloy, the orientation changes to (0 5 4) [22–4 5] after 16 h of annealing. - Highlights: • Texture and microstructure in cold-rolled FePd alloy was investigated during annealing using EBSD. • The recrystallized texture of 50% cold-rolled FePd is (0 1 0) [11 0 1] at 530 °C for 400 hours. • The recrystallized texture of 90% cold-rolled FePd is changed to (0 5 4) [22–4 5] at 530 °C after 16 hours.

  16. EVOLUTION OF COLD STREAMS AND THE EMERGENCE OF THE HUBBLE SEQUENCE

    Energy Technology Data Exchange (ETDEWEB)

    Cen, Renyue, E-mail: cen@astro.princeton.edu [Princeton University Observatory, Princeton, NJ 08544 (United States)

    2014-07-01

    A new physical framework for the emergence of the Hubble sequence is outlined, based on novel analyses performed to quantify the evolution of cold streams of a large sample of galaxies from a state-of-the-art ultra-high resolution, large-scale adaptive mesh-refinement hydrodynamic simulation in a fully cosmological setting. It is found that the following three key physical variables of galactic cold inflows crossing the virial sphere substantially decrease with decreasing redshift: the number of streams N {sub 90} that make up 90% of concurrent inflow mass flux, average inflow rate per stream M-dot {sub 90} and mean (mass flux weighted) gas density in the streams n {sub gas}. Another key variable, the stream dimensionless angular momentum parameter λ, is found to instead increase with decreasing redshift. Assimilating these trends and others naturally leads to a physically coherent scenario for the emergence of the Hubble sequence, including the following expectations: (1) the predominance of a mixture of disproportionately small irregular and complex disk galaxies at z ≥ 2 when most galaxies have multiple concurrent streams, (2) the beginning of the appearance of flocculent spirals at z ∼ 1-2 when the number of concurrent streams are about 2-3, (3) the grand-design spiral galaxies appear at z ≤ 1 when galaxies with only one major cold stream significantly emerge. These expected general trends are in good accord with observations. Early-type galaxies are those that have entered a perennial state of zero cold gas stream, with their abundance increasing with decreasing redshift.

  17. Microtextural evolution of different TRC AA8006 alloy sections with homogenization

    Institute of Scientific and Technical Information of China (English)

    Zhong-wei Chen; Long-fei Shen; Jing Zhao

    2015-01-01

    Grain microtexture evolution in twin-roll cast AA8006 alloy sheets subjected to different treatments was investigated using elec-tron backscatter diffraction. The textures of rolling-transverse and normal-transverse sections were characterized in original as-cast twin-roll casting and cold-rolled samples as well as samples homogenized at 500°C for 8 h and at 580°C for 4 h. It is found that grains on both the rolling-transverse and normal-transverse sections of cold-rolled samples are made finer by rolling deformation and coarsened after homog-enization. Annealing temperature has a stronger effect on the microstructural evolution than annealing time. The grain growth direction is parallel to the normal-transverse section, while grain deformation is more stable on the rolling direction than on the normal direction. The rolling orientations display more obvious anisotropy on the normal-transverse sections than on the rolling-transverse sections. Grain recrys-tallization and growth occur much easier on the normal-transverse section than on the rolling-transverse section for samples homogenized at 500°C for 8 h. A special misorientation relationship between cold deformation texture, such as S orientation{123}and cube orienta-tion|Xaxis [cubic], and recrystallization texture after homogenization, such as R orientation{124}and P orientation{011}, is observed.

  18. Interfacial layers evolution during annealing in Ti-Al multi-laminated composite processed using hot press and roll bonding

    Science.gov (United States)

    Assari, A. H.; Eghbali, B.

    2016-09-01

    Ti-Al multi-laminated composites have great potential in high strength and low weight structures. In the present study, tri-layer Ti-Al composite was synthesized by hot press bonding under 40 MPa at 570 °C for 1 h and subsequent hot roll bonding at about 450 °C. This process was conducted in two accumulative passes to 30% and to 67% thickness reduction in initial and final passes, respectively. Then, the final annealing treatments were done at 550, 600, 650, 700 and 750 °C for 2, 4 and 6 h. Investigations on microstructural evolution and thickening of interfacial layers were performed by scanning electron microscopes, energy dispersive spectrometer, X-ray diffraction and micro-hardness tests. The results showed that the thickening of diffusion layers corresponds to amount of deformation. In addition to thickening of the diffusion layers, the thickness of aluminum layers decreased and after annealing treatment at 750 °C for 6 h the aluminum layers were consumed entirely, which occurred because of the enhanced interdiffusion of Ti and Al elements. Scanning electron microscope equipped with energy dispersive spectrometer showed that the sequence of interfacial layers as Ti3Al-TiAl-TiAl2-TiAl3 which are believed to be the result of thermodynamic and kinetic of phase formation. Micro-hardness results presented the variation profile in accordance with the sequence of intermetallic phases and their different structures.

  19. Advanced Treatment of Cold-rolling Wastewater from Laiwu Steel Group and Reuse Engineering%冷轧废水深度处理及回用工程

    Institute of Scientific and Technical Information of China (English)

    张金平; 周欢; 张章; 赵文禹

    2012-01-01

    将冷轧过程产生的含油废水、脱脂平整废水、酸碱废水、生活污水、循环水排污水分流处理后收集,采用电催化氧化/MBR/反渗透进行深度处理并回用,处理水量为50 m3/h.工程实践表明,在实施有效预处理的条件下,出水水质优于《钢铁工业给水排水设计手册》中工业新水水质指标,废水处理成本为3.47元/m3,出水全部回用到循环水系统中,可节约工业新水消耗量为17×104 m3/a.%After the oily wastewater, degreasing leveling wastewater, acid-base wastewater, sewage and circulating water discharge produced during cold-rolling are respectively treated and collected, the combined process of electric catalytic oxidation, MBR and RO is used for advanced treatment and reuse. The treatment capacity is 50 mVh. The engineering practice shows that after the effective pretreat-ment, the effluent quality from the advanced treatment is better than the industrial new water quality index in Design Manual for Steel Industrial Water Supply and Wastewater. The wastewater treatment cost is 3.47 yuan/ra3, all the effluent is reused in the circulating water system, and the industrial new water consumption of 17 × 104 mVa is saved.

  20. Kinetic modeling on CO{sub 2} capture using basic oxygen furnace slag coupled with cold-rolling wastewater in a rotating packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Chang, E.-E. [Department of Biochemistry, Taipei Medical University, Taipei, Taiwan (China); Chen, Tse-Lun; Pan, Shu-Yuan [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan (China); Chen, Yi-Hung [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taiwan (China); Chiang, Pen-Chi, E-mail: pcchiang@ntu.edu.tw [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan (China)

    2013-09-15

    Highlights: • CO{sub 2} is captured effectively and efficiently by carbonation of BOFS with CRW in RPB. •Direct and indirect carbonation are performed with a capacity of 277 g CO{sub 2}/kg BOFS. • Material balance in the RPB was established with a recovery ratio from 90% to 110%. • The product of calcite formed and coated on BOFS was confirmed by SEM-EDX and XRD. • Kinetics model of carbonation of BOFS in CRW via RPB was developed by mass balance. -- Abstract: In this study, direct and indirect carbonation of basic oxygen furnace slag (BOFS) coupled with cold-rolling wastewater (CRW) was carried out via a rotating packed bed (RPB). The solid products were qualitatively characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) and quantitatively analyzed with thermogravimetric analysis (TGA). The leachate was analyzed with inductively coupled plasma-optical emission spectroscopy (ICP-OES). The results indicate that the maximum achievable carbonation conversion (MACC) of BOFS was 90.7%, corresponding to a capture capacity of 0.277 g CO{sub 2}/g of BOFS, by direct carbonation with CRW under a rotation speed of 750 rpm at 30 °C for 20 min. In addition, CO{sub 2} mass balance among the gas, liquid, and solid phases within an RPB was well-developed, with an error less than 10%, to confirm the actual CO{sub 2} capture capacity of BOFS with precision and accuracy. Furthermore, a reaction kinetic model based on mass balance was established to determine the reaction rate constant for various liquid agents (CRW and pure water). It was concluded that co-utilization of alkaline wastes including BOFS and CRW via the RPB is a novel approach for both enhancing CO{sub 2} capture capacity and reducing the environmental impacts of alkaline wastes.

  1. Corrosion protection of cold-rolled steel with alkyd paint coatings composited with submicron-structure types polypyrrole-modified nano-size alumina and carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Gergely, Andras, E-mail: andras.gergely@ttk.mta.hu [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Pusztaszeri ut 59-67, 1025 Budapest (Hungary); Paszti, Zoltan; Hakkel, Orsolya; Drotar, Eszter [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Pusztaszeri ut 59-67, 1025 Budapest (Hungary); Mihaly, Judith [Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Pusztaszeri ut 59-67, 1025 Budapest (Hungary); Kalman, Erika [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Pusztaszeri ut 59-67, 1025 Budapest (Hungary)

    2012-11-01

    Highlights: Black-Right-Pointing-Pointer Alumina/carbon nanotube (CNT) supported polypyrrole (PPy) particles were prepared. Black-Right-Pointing-Pointer Various paint compositions with alkyd binder were immersion tested. Black-Right-Pointing-Pointer Alumina-supported PPy based coating provided steel protection in NaCl solution. Black-Right-Pointing-Pointer Polyelectrolyte modified CNT embedded coating afforded long-term stable protection. Black-Right-Pointing-Pointer sulphonated CNT loaded coating indicated firm corrosion resistance in HCL solution. Black-Right-Pointing-Pointer Results are interpreted on the basis of nano and microstructure of the particles. - Abstract: This paper is focused on studying corrosion protection of cold-rolled steel with alkyd paint coatings comprising nano-size alumina and either polystyrene-sulphonate (PSS) modified or sulphonated multi-walled carbon nanotube (MWCNT) supported polypyrrole (PPy). Single layer coatings (in thickness of 40 {+-} 5 {mu}m) comprising PPy deposited alumina and PSS modified MWCNT supported PPy afforded viable protection during the 1 M sodium chloride test. The coatings containing PSS modified and weakly sulphonated MWCNTs (at volume fractions of 9.9 Multiplication-Sign 10{sup -4} and 2.5 Multiplication-Sign 10{sup -4}) with PPy volume fractions of 3.5 Multiplication-Sign 10{sup -3} and 2.5 Multiplication-Sign 10{sup -3} provided effective corrosion prevention during the 1 M sodium chloride and hydrochloric acid solution tests. While inhibitor particles were characterised by infrared spectroscopy, corrosion products formed at the paint-steel interface were studied by X-ray photoelectron spectroscopy. Apart from the electron microscopy observations, rheology study of three-dimensional structure of the inhibitor particles was performed in dispersions at similar compositions to those used for the paint formulations. Thus, protection mechanism relating to both types of immersion tests is discussed in terms of

  2. A feasibility study on different NDT techniques used for testing bond quality in cold roll bonded Al-Sn alloy/steel bimetal strips

    Directory of Open Access Journals (Sweden)

    Tallafuss Philipp Johannes

    2017-01-01

    Full Text Available This paper presents non-destructive testing (NDT results for the detection of bond defects in aluminium-tin (Al-Sn alloy/steel bimetal strips. Among all types of bimetal strip that are used in the automotive industry for plain journal engine bearings, Al-Sn alloys cold roll bonded (CRB onto steel backing is the most common type. The difficulty to evaluate the metallurgical bond between the two dissimilar metals is a major industrial concern, which comprises the risk that bearings fail in the field. Considering the harsh performance requirements, 100% online non-destructive testing would be desirable to significantly reduce the business risk. Nowadays bimetal strip manufacturers still rely on destructive testing through different peel-off tests. This work offers the results from four independent NDT studies, using active thermography, shearography, ultrasound and guided wave electromagnetic acoustic transducers (EMATs and samples with different artificially implanted defects, to explore the feasibility to qualitatively indicate the occurrence of bond defects. A destructive peel off test was used to correlate the NDT results with known bond quality. The studies were done under laboratory conditions, and in case of ultrasound also online under production conditions. During the ultrasound online test, the requirements that a NDT technique has to fulfil for online inspection of Al-Sn alloy/steel bimetal strip were established. For active thermography, shearography and guided wave EMAT techniques, it was theoretically analysed, if the laboratory test results could be transferred to testing under production conditions. As a result, guided waves using EMATs, among the four tested methods, are best suited for online inspection of Al-Sn alloy/steel bimetal strip. This research was carried out in collaboration with MAHLE Engine Systems UK Ltd., an Al-Sn alloy/steel bimetal strip manufacturer for the automotive industry.

  3. [Isolation of an excellent bio-flocculant-producing strain and its application in the treatment of cold-rolling waste oily water].

    Science.gov (United States)

    Lei, Guo-Yuan; Ding, Cui-Ping; Yang, Jia-Xuan

    2011-09-01

    An excellent strain (designated as T-3) which produces bio-flocculants was isolated from soil samples, and identified as Klebsiella sp. species based on the analysis of morphology, physiology and biochemistry and 16S rDNA sequences measurement. The effects of culture conditions such as pH values, temperature, carbon sources and nitrogen sources on bio-flocculants production by T-3 strain were studied. The experiment results show that T-3 strain has better adaptability to carbon sources and nitrogen sources, and higher capacity of bio-flocculants was obtained when the initial pH value of culture and temperature were 9 and 25 degrees C respectively. Based on the colorimetric reactions of proteins and polysaccharide substance, ultraviolet scanning analysis and Fourier Transform Infrared Spectroscopy analysis, it is found that the bio-flocculants produced by T-3 strain contains -OH and -COO(-) groups and belongs to anionic type flocculant. Moreover, the main component is polysaccharides. The treatment of oily cold-rolling wastewater by the bio-flocculant was investigated and the better result was obtained. When the dosages of CaCl2, bio-flocculants and poly aluminium chloride were 4 g x L(-1), 10% (volume fraction) and 1 g x L(-1) respectively, and the pH value was 7.0, the oil concentration, COD and turbidity were decreased to 10 mg x L(-1), 218.4 mg x L(-1) and 1.36 from 4 819 mg x L(-1), 28 456.8 mg x L(-1) and 3 950 with the removal efficiencies of 99.79%, 92.32% and 99.97% respectively. The interaction between flocculant and oily droplets is achieved by the interaction of Van der Waals force, hydrogen bond and the bridged coordination of Ca2+, in which the bridged coordination of Ca2+ is the dominant.

  4. Darwin, Engels und die Rolle der Arbeit in der biologischen und kulturellen Evolution des Menschen

    Science.gov (United States)

    Reichholf, Josef H.

    Im Jahre 1876, 5 Jahre nach Erscheinen von Darwins Buch über die Evolution des Menschen und die sexuelle Selektion (Darwin 1871), veröffentlichte Friedrich Engels den berühmt gewordenen Essay "Anteil der Arbeit an der Menschwerdung des Affen“ (Engels 1876). Die Kernfrage darin lautet in Kurzform: Warum hat der Mensch eigentlich ein Bedürfnis nach Arbeit? Engels Antwort wird nachfolgend näher betrachtet und vom gegenwärtigen Kenntnisstand aus beurteilt. Wie sich zeigen wird, beantworten seine Überlegungen die Frage nicht wirklich. Sie ist weiterhin offen. Es können lediglich einige zusätzliche Anhaltspunkte zur Diskussion gestellt werden. Angesichts des drängenden Problems millionenfacher Arbeitslosigkeit und der Forderungen nach einem "Grundrecht auf Arbeit“ kommt den Überlegungen zum möglichen Ursprung des Bedürfnisses nach Arbeit mehr als nur akademisches Interesse zu.

  5. Evolution of microstructure at hot band annealing of ferritic FeSi steels

    Science.gov (United States)

    Schneider, Jürgen; Li, Guangqiang; Franke, Armin; Zhou, Bowen

    2017-02-01

    The magnetic properties of the finally fabricated nonoriented FeSi steels critically depend on the microstructure and on the occurring crystallographic texture. The fabrication route comprises hot rolling, coiling and cooling, hot band annealing before cold rolling (optional), cold rolling and the final thermal treatment. As well known there is an interplay between the microstructure and texture during the various processing steps. For that reason, it is of interest to know more on the evolution of the microstructure at hot band annealing of hot band prepared in different ways. In this paper we will summarize our recent results on the evolution of microstructure during thermal annealing of hot band: thermal treatment following immediately the last pass of hot rolling or a hot band annealing as a separate processing step before cold rolling.

  6. From nanoplates to microtubes and microrods: a surfactant-free rolling mechanism for facile fabrication and morphology evolution of Ag2S films.

    Science.gov (United States)

    Li, Da-Peng; Zheng, Zhi; Lei, Yan; Yang, Feng-Ling; Ge, Su-Xiang; Zhang, Yi-Dong; Huang, Bao-Jun; Gao, Yuan-Hao; Wong, Ka-Wai; Lau, Woon-Ming

    2011-06-27

    By a simple and facile wet-chemistry technique without any surfactant, various shapes of Ag(2)S crystals--including leaflike pentagonal nanoplates, crinkly nanoscrolls, hexagonal prismlike microtubes, and microrods--were fabricated in situ on a large-area silver-foil surface separately. Detailed experiments revealed that the Ag(2)S nanoplates were formed just by immersing the silver foil in a sulfur/ethanol solution at room temperature and atmospheric pressure, and they subsequently rolled into nanoscrolls and further grew into microtubes and microrods under solvothermal conditions. Inspired by the natural curling of a piece of foliage, we proposed a surfactant-free rolling mechanism to interpret the observed morphological evolution from lamellar to tubular structures. Based on these simple, practical, and green chemical synthetic routes, we can easily synthesize lamellar, scrolled, tubular, and clubbed Ag(2)S crystals by simply adjusting the reaction temperature, pressure, and time. It is very interesting to note that the current rolling process is quite different from the previous reported rolling mechanism that highly depends on the surfactants; we revealed that the lamellar Ag(2)S could be rolled into tubular structures without using any surfactant or other chemical additives, just like the natural rolling process of a piece of foliage. Therefore, this morphology-controlled synthetic route of Ag(2)S crystals may provide new insight into the synthesis of metal sulfide semiconducting micro-/nanocrystals with desired morphologies for further industrial applications. The optical properties of the pentagonal Ag(2)S nanoplates/film were also investigated by UV/Vis and photoluminescence (PL) techniques, which showed large blue-shift of the corresponding UV/Vis and PL spectra.

  7. Effect of Cold Deformation on Phase Evolution and Mechanical Properties in an Austenitic Stainless Steel for Structural and Safety Applications

    Institute of Scientific and Technical Information of China (English)

    S K Ghosh; P Mallick; P P Chattopadhyay

    2012-01-01

    The effects of cold deformation on the formation of strain induced α’ martensite and mechanical properties of an austenitic stainless steel have been examined.X-ray diffraction analysis has revealed that 30% and 40% cold rolling have resulted in the formation of 24% and 31.5% martensite respectively.Microstructural investigation has demonstrated that the formation of martensite is enhanced with increase in the percent deformation at 0 ℃.Investigation of mechanical properties reveals that hardness,yield strength and tensile strength values increase where as percent elongation drops with increasing deformation.The fractographic observation corroborates the tensile results.Examination of sub-surface at the fractured end of the tensile sample manifests that void/microcrack nucleation occurs in the interfacial regions of the martensite phase as well as at the austenite-martensite interface

  8. Analysis on Control System for Carrousel Coiler in Continuous Cold Rolling Production Line%冷连轧卡罗赛尔卷取机控制系统分析

    Institute of Scientific and Technical Information of China (English)

    王文天; 吴晓宁

    2014-01-01

    介绍了鞍钢1450冷连轧生产线卡罗赛尔卷取机的生产工艺和运行状况,重点讨论了卡罗赛尔卷取机的运行过程,并对卷取机控制过程中的逻辑程序进行了分析,自主开发了卷取机顺序控制程序。应用结果表明,轮盘旋转顺序设计满足工艺要求,控制效果良好,提高了冷连轧机轧制效率。%The production process and operation status of Carrousel coiler in 1450 mm continuous cold rolling production line of Angang is introduced. Particularly the operational process of Carrousel coiler is discussed emphatically and the logical program for controlling the coiling process of Carrousel coiler is also analyzed. Based on the analytical results the sequence control procedure for Carrousel coiler is developed independently. The application results show that the sequential design for the turbine disk can meet the requirements of the production technology and the control effect is so good that the rolling productivity of the continuous cold rolling production line is improved.

  9. An Isocurvature Cold Dark Matter Cosmogony. I. A Worked Example of Evolution through Inflation

    Science.gov (United States)

    Peebles, P. J. E.

    1999-01-01

    I present a specific worked example of evolution through inflation to the initial conditions for an isocurvature cold dark matter (ICDM) model for structure formation. The model invokes three scalar fields: one that drives power-law inflation, one that survives to become the present-day CDM, and one that gives the CDM field a mass that slowly decreases during inflation and therefore ``tilts'' the primeval mass fluctuation spectrum of the CDM. The functional forms for the potentials and the parameter values that lead to an observationally acceptable model for structure formation do not seem to be out of line with current ideas about the physics of the very early universe. I argue in an accompanying paper that the model offers a not unacceptable fit to main observational constraints.

  10. The evolution of large-scale structure in a universe dominated by cold dark matter

    Science.gov (United States)

    Davis, M.; Efstathiou, G.; Frenk, C. S.; White, S. D. M.

    1985-01-01

    The results of numerical simulations of nonlinear gravitational clustering in universes dominated by weakly interacting, 'cold' dark matter are presented. The numerical methods used and the way in which initial conditions were generated are described, and the simulations performed are catalogued. The evolution of the fundamental statistical properties of the models is described and their comparability with observation is discussed. Graphical comparisons of these open models with the observed galaxy distribution in a large redshift survey are made. It is concluded that a model with a cosmological density parameter omega equal to one is quite unacceptable if galaxies trace the mass distribution, and that models with omega of roughly two, while better, still do not provide a fully acceptable match with observation. Finally, a situation in which galaxy formation is suppressed except in sufficiently dense regions is modelled which leads to models which can agree with observation quite well even for omega equal to one.

  11. Molecular gas content of H I monsters and implications to cold gas content evolution in galaxies

    Science.gov (United States)

    Lee, Cheoljong; Chung, Aeree; Yun, Min S.; Cybulski, Ryan; Narayanan, G.; Erickson, N.

    2014-06-01

    We present 12CO (J = 1 → 0) observations of a sample of local galaxies (0.04 monsters'. The data were obtained using the redshift search receiver on the five college radio astronomy observatory (FCRAO) 14 m telescope. The sample consists of 20 H I-massive galaxies with MH I > 3 × 1010 M⊙ from the Arecibo Legacy Fast ALFA (ALFALFA) survey and 8 low surface brightness galaxies (LSBs) with a comparable MH I(>1.5 × 1010 M⊙). Our sample selection is purely based on the amount of neutral hydrogen, thereby providing a chance to study how atomic and molecular gas relate to each other in these H I-massive systems. We have detected CO in 15 out of 20 ALFALFA selected galaxies and 4 out of 8 LSBs with molecular gas mass MH2 of (1-11)× 109 M⊙. Their total cold gas masses of (2-7) × 1010 M⊙ make them some of the most gas-massive galaxies identified to date in the Local Universe. Observed trends associated with H I, H2, and stellar properties of the H I massive galaxies and the field comparison sample are analysed in the context of theoretical models of galaxy cold gas content and evolution, and the importance of total gas content and improved recipes for handling spatially differentiated behaviours of disc and halo gas are identified as potential areas of improvement for the modelling.

  12. Molecular Gas Content of HI Monsters and Implications to Cold Gas Content Evolution in Galaxies

    CERN Document Server

    Lee, Cheoljong; Yun, Min S; Cybulski, Ryan; Narayanan, G; Erickson, N

    2014-01-01

    We present 12CO (J=1-0) observations of a sample of local galaxies (0.043e10Msun from the ALFALFA survey and 8 LSBs with a comparable M(HI) (>1.5e10Msun). Our sample selection is purely based on the amount of neutral hydrogen, thereby providing a chance to study how atomic and molecular gas relate to each other in these HI-massive systems. We have detected CO in 15 out of 20 ALFALFA selected galaxies and 4 out of 8 LSBs with molecular gas mass M(H2) of (1-11)e9Msun. Their total cold gas masses of (2-7e10Msun make them some of the most gas-massive galaxies identified to date in the Local Universe. Observed trends associated with HI, H2, and stellar properties of the HI massive galaxies and the field comparison sample are analyzed in the context of theoretical models of galaxy cold gas content and evolution, and the importance of total gas content and improved recipes for handling spatially differentiated behaviors of disk and halo gas are identified as potential areas of improvement for the modeling.

  13. Experimental and numerical study of residual stress evolution in cold spray coating

    Science.gov (United States)

    Ghelichi, R.; Bagherifard, S.; MacDonald, D.; Fernandez-Pariente, I.; Jodoin, B.; Guagliano, M.

    2014-01-01

    Residual stresses are among the most important factors affecting the properties and service lifetime of materials and components. In the cold spray coating process there are two contradictory factors that influence the final residual stress state of the coated material; the impact of the high velocity micron-size particles induces compressive residual stresses, whereas the gas temperature can have an opposing annealing effect on the induced stresses. These two simultaneous phenomena can in turn change the residual stress profile, thus complicate the assessment of the final residual stress state. In this paper the residual stress evolution during cold spray coating process has been studied through experimental measurements and numerical simulations performed on several series of samples coated using different spray process parameters. A detailed finite element (FE) analysis of the process has been developed to calculate the stresses induced through impacts and then the annealing effect has been taken into account through an analytical model. The results of the experiments and numerical-analytical approach confirm the considerable effect of annealing on the eventual stress distribution in the coated samples.

  14. Tracing the Cosmological Evolution of Stars and Cold Gas with CMB Spectral Surveys

    Science.gov (United States)

    Switzer, Eric R.

    2017-04-01

    A full account of galaxy evolution in the context of ΛCDM cosmology requires measurements of the average star-formation rate (SFR) and cold gas abundance across cosmic time. Emission from the CO ladder traces cold gas, and [C ii] fine structure emission at 158 μ {{m}} traces the SFR. Intensity mapping surveys the cumulative surface brightness of emitting lines as a function of redshift, rather than individual galaxies. CMB spectral distortion instruments are sensitive to both the mean and anisotropy of the intensity of redshifted CO and [C ii] emission. Large-scale anisotropy is proportional to the product of the mean surface brightness and the line luminosity-weighted bias. The bias provides a connection between galaxy evolution and its cosmological context, and is a unique asset of intensity mapping. Cross-correlation with galaxy redshift surveys allows unambiguous measurements of redshifted line brightness despite residual continuum contamination and interlopers. Measurement of line brightness through cross-correlation also evades cosmic variance and suggests new observation strategies. Galactic foreground emission is ≈ {10}3 times larger than the expected signals, and this places stringent requirements on instrument calibration and stability. Under a range of assumptions, a linear combination of bands cleans continuum contamination sufficiently that residuals produce a modest penalty over the instrumental noise. For PIXIE, the 2σ sensitivity to CO and [C ii] emission scales from ≈ 5× {10}-2 {kJy} {{sr}}-1 at low redshift to ≈ 2 {kJy} {{sr}}-1 by reionization.

  15. Microstructure, flow behavior, and bulk texture evolution of cold drawn copper–silver composites

    Energy Technology Data Exchange (ETDEWEB)

    Dodla, S., E-mail: srihari.dodla@st.ovgu.de [Institut für Mechanik, Otto-von-Guericke-Universität Magdeburg, D-39106 Magdeburg (Germany); Thiem, P.; Krüger, M. [Institut für Werkstoff- und Fügetechnik, Otto-von-Guericke-Universität Magdeburg, D-39106 Magdeburg (Germany); Dietrich, D. [Institut für Werkstoffwissenschaft und Werkstofftechnik, Technische Universität Chemnitz, D-09107 Chemnitz (Germany); Bertram, A. [Institut für Mechanik, Otto-von-Guericke-Universität Magdeburg, D-39106 Magdeburg (Germany)

    2015-10-25

    In the last 20 years, several groups used nanostructured composites to produce high strength conductor materials for magnetic applications. The mechanical strength of Cu–Ag composites is strongly influenced by metal forming operations. Within the scope of the paper, the microstructure, the mechanical behavior, and the texture evolution are investigated for two cold drawn Cu-63wt%Ag composite rods. The aim of these investigations is to understand the influence of the microstructure and texture evolution on the mechanical behavior. The investigation is carried out using optical microscopy, scanning electron microscopy (SEM) along with electron backscattered diffraction (EBSD), X-ray diffraction measurements (XRD), and compression testing. The microscopic images show that the drawn samples mainly have a lamellar structure of Cu and Ag phases. However, elliptical shaped regions of primarily solidified copper solid solution are also observed. With increase of plastic deformation, the average lamella thickness of both phases has been decreased. EBSD measurements show that abundant banded regions are observed in the Ag phase while very few banded regions are present in the Cu phase. The bulk XRD measurements reveal that both phases of the drawn samples initially have the same type of texture, and both phases develop the same brass-type [110]〈112〉 texture. The texture intensity increases for both phases as the drawing strain increases. Compression tests are performed at constant strain rate of 10{sup −4} s{sup −1} at room temperature. The stress–strain curves under compression are presented for two different drawn samples. The texture measurements after compression reveal that the texture becomes more pronounced. - Highlights: • Two cold drawn Cu–Ag rods are investigated. • Both phases of the drawn samples initially have the same type of texture. • Several banded regions are observed in the Ag phase. • Texture becomes more pronounced after compression.

  16. The cold mode: A phenomenological model for the evolution of density perturbations in the intracluster medium

    CERN Document Server

    Singh, Ashmeet

    2014-01-01

    Cool cluster cores are in global thermal equilibrium but are locally thermally unstable. We study a nonlinear phenomenological model for the evolution of density perturbations in the ICM due to local thermal instability and gravity. We have analyzed and extended a model for the evolution of an over dense blob in the ICM. We find two regimes in which the over-dense blobs can cool to thermally stable low temperatures. One for large $t_{{\\rm {cool}}} / t_{\\rm {ff}}$ ($t_{{\\rm {cool}}}$ is the cooling time and $t_{{\\rm {ff}}}$ is the free fall time), where a large initial over-density is required for thermal runaway to occur; this is the regime which was previously analyzed in detail. We discover a second regime for $t_{\\rm {cool}} / t_{\\rm {ff}} \\lesssim 1$ (in agreement with Cartesian simulations of local thermal instability in an external gravitational field), where runaway cooling happens for arbitrarily small amplitudes. Numerical simulations have shown that cold gas condenses out more easily in a spherical ...

  17. The Molecular Basis of Evolution and Disease: A Cold War Alliance.

    Science.gov (United States)

    Suárez-Díaz, Edna

    2017-03-28

    This paper extends previous arguments against the assumption that the study of variation at the molecular level was instigated with a view to solving an internal conflict between the balance and classical schools of population genetics. It does so by focusing on the intersection of basic research in protein chemistry and the molecular approach to disease with the enactment of global health campaigns during the Cold War period. The paper connects advances in research on protein structure and function as reflected in Christian Anfinsen´s The molecular basis of evolution, with a political reading of Emilé Zuckerkandl and Linus Pauling's identification of molecular disease and evolution. Beyond atomic fallout, these advances constituted a rationale for the promotion of genetic surveys of human populations in the Third World, in connection with international health programs. Light is shed not only on the experimental roots of the molecular challenge but on the broader geopolitical context where the rising role of biomedicine and public health (particularly the malaria eradication campaigns) had an impact on evolutionary biology.

  18. Effect of casting parameters and deformation on microstructure evolution of twin-roll casting magnesium alloy AZ31

    Institute of Scientific and Technical Information of China (English)

    JU Dong-ying; HU Xiao-dong

    2006-01-01

    Twin roll casting method is a promising route to directly produce magnesium alloy strip. It is a rapid solidification process with high temperature gradient combined with thermal flow and rolling deformation in the casting region. As-cast strip with proper microstructure is requested to serve as next rolling feedstock. However the microstructure of as-cast strip is sensitive for casting conditions during the casting process and the as-cast microstructure greatly affects the mechanical properties. In this work,the effect of casting speed,pouring temperature,deformation as well as anneal process on microstructure and mechanical properties were investigated. The results revels that twin-roll casting process can effectively refine the grain size,improve the morphology and distribution states of Mg17Al12. The homogenization treatment time can be shorted for the fine microstructure and lower the cost dramatically for the next forming process.

  19. Effect of current frequency on the mechanical properties, microstructure and texture evolution in AZ31 magnesium alloy strips during electroplastic rolling

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaopei [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Beijing National Center for Electron Microscopy, School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Materials (MOE), Tsinghua University, Beijing 100084 (China); Tang, Guoyi; Kuang, Jie; Li, Xiaohui [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Zhu, Jing, E-mail: jzhu@tsinghua.edu.cn [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Beijing National Center for Electron Microscopy, School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Materials (MOE), Tsinghua University, Beijing 100084 (China)

    2014-08-26

    The effect of electroplastic rolling (ER) on the mechanical properties, microstructure and texture in the AZ31 magnesium alloy strips has been investigated by tensile testing and electron back scattered diffraction (EBSD) methods. It is shown that the mechanical properties, microstructure, and texture are highly current frequency-dependent. Best mechanical properties are obtained from the 500 Hz ER specimen by carrying out tensile tests for all the rolled strips. Besides, the frequencies of twin boundaries, which are reduced to the minimum at 500 Hz, vary with the current frequency. Moreover, it can be seen from the calculated (0001) and (101{sup ¯}0) pole figures that texture evolved into an obvious off-basal texture, and non-basal slip systems are activated under 500 Hz. The mechanisms of twinning growth and texture evolution in AZ31 magnesium alloy strips during ER are considered to be responsible for the experimental results.

  20. 冷轧中Mn-TRIP钢的机理与研发进展%Mechanism and development progress of cold-rolled medium Mn-TRIP steel

    Institute of Scientific and Technical Information of China (English)

    韩启航; 张玉龙; 王利

    2015-01-01

    As one of the most important third generation automotive steels , the medium Mn-TRIP steel has drawn more and more attentions from domestic and foreign automotive and steel enterprises .The latest progress in the mechanism research and development is introduced .Medium Mn-TRIP steel is mainly composed of nanosized to microsized ferrite , metastable austenite and possibly a certain amount of martensite , which is significantly different from other advanced high strength steels in terms of the microstructure characteristics and deformation mechanism .Many academic institutes have done a lot of work , including the Mn component design , phase transformation characterization, Lüders strain of ultra-fine grains, transformation induced work hardening , austenitic partial dislocation slip and so on .Furthermore, 1 000~1 200 MPa cold rolled medium Mn-TRIP steel and hot dip galvanized medium Mn-TRIP steel have been industrialized , and their strength-ductility balance is higher than 35 GPa· %, which reveals that more industrialization application has been performed based on the academic research .%中Mn-TRIP钢作为第三代汽车用钢研发的重点,从21世纪初就得到越来越多国内外汽车及钢铁企业的关注。介绍了中Mn-TRIP钢种的最新机理研究与工业化进展。中Mn-TRIP钢主要由纳米级至微米级铁素体和亚稳奥氏体构成,有时也含有一定比例的马氏体,其组织特征和变形机理与其他先进高强钢有显著不同。众多科研院所做了大量工作,包括中Mn成分设计、相变精细结构表征、超细晶Lüders应变行为、相变诱导加工硬化、奥氏体不全位错滑移等,从而对中Mn-TRIP钢有了更为深入的认识。1000~1200 MPa级冷轧中Mn-TRIP钢和热镀锌中Mn-TRIP 钢已经成功实现了工业化试制,其强塑积大于35 GPa ·%,标志着冷轧中Mn-TRIP钢正逐步由基础研究向工业化生产推进。

  1. Ti微合金化冷轧高强钢的再结晶温度研究%Study on Recrystallization Temperature of Ti Microalloyed High Strength Steel in Cold-Rolled Strips

    Institute of Scientific and Technical Information of China (English)

    吕盛夏; 陈事; 毛新平; 王喜; 朱达炎; 霍向东

    2011-01-01

    The recrystallization temperature of Ti microalloyed high strength steel in cold rolling were in vestigated by means of microhardness testing, metallographic structure observation and isothermal annea ling for half an hour. The results shown that the regulations of recrystallization were basically the same in the different percentage of cold-rolling reduction steels, and the recrystallization temperature of steel had a little drop trend with the percentage of cold-rolling reduction increasing. The process was defined recov ery at temperatures below 640 ℃ , a large number of equiaxed grains nucleated, and the microhardness rapidly reduced with temperature increasing. Recrystallization grains grow up abnormally when the tem perature rose to 840 ℃. The recrystallization temperature of steel rose to 700 ~710 ℃ , large amount of nanometer TiC particles and solute atoms existed in steel were main reasons for the high recrystallization temperature.%采用半小时等温法、显微硬度测量和金相组织观察等试验手段,研究了Ti微合金化冷轧高强钢的再结晶温度.结果发现:不同变形量的冷轧板再结晶规律基本相同,再结晶温度随变形量增加略有降低;640℃以下为回复阶段,随着温度升高,等轴晶大量形核长大,硬度迅速降低,到840℃再结晶晶粒反常长大;该钢种的再结晶温度高达700 ~710℃,钢中大量纳米级TiC析出物和溶质原子是再结晶温度提高的主要原因.

  2. Hot rolling of thick uranium molybdenum alloys

    Science.gov (United States)

    DeMint, Amy L.; Gooch, Jack G.

    2015-11-17

    Disclosed herein are processes for hot rolling billets of uranium that have been alloyed with about ten weight percent molybdenum to produce cold-rollable sheets that are about one hundred mils thick. In certain embodiments, the billets have a thickness of about 7/8 inch or greater. Disclosed processes typically involve a rolling schedule that includes a light rolling pass and at least one medium rolling pass. Processes may also include reheating the rolling stock and using one or more heavy rolling passes, and may include an annealing step.

  3. Neutron and X-ray diffraction study of residual and internal stress evolution in pearlitic steel during cold drawing

    Science.gov (United States)

    Kriška, M.; Tacq, J.; Van Acker, K.; Seefeldt, M.; Van Petegem, S.

    2012-02-01

    Neutron and X-ray diffraction were used to study the residual and internal stress evolution during cold drawing in pearlitic steel wires. A selection of high strength filaments drawn to different reductions has been investigated. In order to compare the evolution of macro and micro residual phase stresses in ferrite, the lattice strain evolution has been studied in axial and transverse direction. In-situ neutron diffraction tests in "Poisson" geometry have been carried out at the TOF strain scanner POLDI at PSI, Switzerland. These tests revealed a significant scatter in mechanical response among differently oriented ferrite grains, including a peculiar response of the {200} reflection, cp. [1, 2].

  4. Cold-start emissions of modern passenger cars at different low ambient temperatures and their evolution over vehicle legislation categories

    Science.gov (United States)

    Weilenmann, Martin; Favez, Jean-Yves; Alvarez, Robert

    The emissions of modern gasoline and diesel passenger cars are reduced by catalysts except in cold-starting. Since catalysts require a certain temperature (typically above 300 °C) to work to full efficiency, emissions are significantly higher during the warm-up phase of the car. The duration of this period and the emissions produced depend on the ambient temperature as well as on the initial temperature of the car's propulsion systems. The additional emissions during a warm-up phase, known as "cold-start extra emissions" (CSEEs) for emission inventory modelling, are mostly assessed by emission measurements at an ambient temperature of 23 °C. However, in many European countries average ambient temperatures are below 23 °C. This necessitates emission measurements at lower temperatures in order to model and assess cold-start emissions for real-world temperature conditions. This paper investigates the influence of regulated pollutants and CO 2 emissions of recent gasoline and diesel car models (Euro-4 legislation) at different ambient temperatures, 23, -7 and -20 °C. We present a survey and model of the evolution of cold-start emissions as a function of different car generations (pre-Euro-1 to Euro-4 legislations). In addition the contribution of CSEEs to total fleet running emissions is shown to highlight their increasing importance. For gasoline cars, it turns out that in average real-world driving the majority of the CO (carbon monoxide) and HC (hydrocarbon) total emissions are due to cold-start extra emissions. Moreover, the cold-start emissions increase considerably at lower ambient temperatures. In contrast, cold-start emissions of diesel cars are significantly lower than those of gasoline cars. Furthermore, the transition from Euro-3 to Euro-4 gasoline vehicles shows a trend for a smaller decline for cold-start extra emissions than for legislative limits. Particle and NO x emission of cold-starts are less significant.

  5. Shewanella spp. genomic evolution for a cold marine lifestyle and in-situ explosive biodegradation.

    Directory of Open Access Journals (Sweden)

    Jian-Shen Zhao

    Full Text Available Shewanella halifaxensis and Shewanella sediminis were among a few aquatic gamma-proteobacteria that were psychrophiles and the first anaerobic bacteria that degraded hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX. Although many mesophilic or psychrophilic strains of Shewanella and gamma-proteobacteria were sequenced for their genomes, the genomic evolution pathways for temperature adaptation were poorly understood. On the other hand, the genes responsible for anaerobic RDX mineralization pathways remain unknown. To determine the unique genomic properties of bacteria responsible for both cold-adaptation and RDX degradation, the genomes of S. halifaxensis and S. sediminis were sequenced and compared with 108 other gamma-proteobacteria including Shewanella that differ in temperature and Na+ requirements, as well as RDX degradation capability. Results showed that for coping with marine environments their genomes had extensively exchanged with deep sea bacterial genomes. Many genes for Na+-dependent nutrient transporters were recruited to use the high Na+ content as an energy source. For coping with low temperatures, these two strains as well as other psychrophilic strains of Shewanella and gamma-proteobacteria were found to decrease their genome G+C content and proteome alanine, proline and arginine content (p-value <0.01 to increase protein structural flexibility. Compared to poorer RDX-degrading strains, S. halifaxensis and S. sediminis have more number of genes for cytochromes and other enzymes related to RDX metabolic pathways. Experimentally, one cytochrome was found induced in S. halifaxensis by RDX when the chemical was the sole terminal electron acceptor. The isolated protein degraded RDX by mono-denitration and was identified as a multiheme 52 kDa cytochrome using a proteomic approach. The present analyses provided the first insight into divergent genomic evolution of bacterial strains for adaptation to the specific cold marine conditions and

  6. Effect of Thermomechanical Processing on Microstructure, Texture Evolution, and Mechanical Properties of Al-Mg-Si-Cu Alloys with Different Zn Contents

    Science.gov (United States)

    Wang, X. F.; Guo, M. X.; Chen, Y.; Zhu, J.; Zhang, J. S.; Zhuang, L. Z.

    2017-07-01

    The effect of thermomechanical processing on microstructure, texture evolution, and mechanical properties of Al-Mg-Si-Cu alloys with different Zn contents was studied by mechanical properties, microstructure, and texture characterization in the present study. The results show that thermomechanical processing has a significant influence on the evolution of microstructure and texture and on the final mechanical properties, independently of Zn contents. Compared with the T4P-treated (first preaged at 353 K (80 °C) for 12 hours and then naturally aged for 14 days) sheets with high final cold rolling reduction, the T4P-treated sheets with low final cold rolling reduction possess almost identical strength and elongation and higher average r values. Compared with the intermediate annealed sheets with high final cold rolling reduction, the intermediate annealed sheets with low final cold rolling reduction contain a higher number of particles with a smaller size. After solution treatment, in contrast to the sheets with high final cold rolling reduction, the sheets with low final cold rolling reduction possess finer grain structure and tend to form a weaker recrystallization texture. The recrystallization texture may be affected by particle distribution, grain size, and final cold rolling texture. Finally, the visco-plastic self-consistent (VPSC) model was used to predict r values.

  7. Evolution of shear bands, free volume, and structure in room temperature rolled Pd{sub 40}Ni{sub 40}P{sub 20} bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yuanli; Shi, Bo; Ma, Zhikun; Li, Jiangong, E-mail: lijg@lzu.edu.cn

    2015-01-19

    The evolution of the shear band, free volume, and structure in room temperature rolled Pd{sub 40}Ni{sub 40}P{sub 20} bulk metallic glass was investigated. It was found that the average shear band density increases monotonously with increasing strain. For the room temperature rolled Pd{sub 40}Ni{sub 40}P{sub 20} bulk metallic glass with a strain of 99%, a high density of shear bands with an average spacing of 31 nm was observed. The absolute free volume content was determined based on the free volume model and found to increase monotonously with increasing strain. The free volume content in the room temperature rolled Pd{sub 40}Ni{sub 40}P{sub 20} bulk metallic glass with a strain of 99% is 34% higher than its as-cast counterpart. Neither phase separation nor crystallization occurs in all the deformed samples. The coordination number of the first coordination shell decreases and the degree of disorder of atomic arrangement increases with increasing strain.

  8. Cold rolling simulation of 6061 aluminium alloy ring based on ABAQUS/Explicit code%基于ABAQUS/Explicit 6061铝合金环件冷轧仿真研究

    Institute of Scientific and Technical Information of China (English)

    罗晓东; 柳浩; 朱永祥

    2014-01-01

    基于ABAQUS/Explicit平台建立了6061铝合金环件冷轧模型,研究环件轧制过程中金属的变形规律,包括环件的咬入和锻透情况、应力-应变分布情况、轧制力与轧制力矩等。研究表明,环件的最终成型质量好,壁厚误差在0.1 mm以内,直径误差在1 mm左右。%Based on ABAQUS/Explicit code,a cold rolling model of 6061 aluminium alloy ring was proposed to study deformation law,such as bite condition,plastic penetration condition,stress and strain distribution,rolling force and rolling moment,and so on. The results show that the formed ring has good quality,the wall thickness error is less than 0.1 mm and the diameter error is about 1 mm.

  9. 铝板带材冷轧机压力 AGC 仿真对比与实验分析%Simulating Comparison and Experimental Analysis of Pressure AGC on Cold Rolling Mill for Aluminum Plate Strip

    Institute of Scientific and Technical Information of China (English)

    安俊静; 白磊; 赵春江; 郝琳璐; 石建辉

    2014-01-01

    The automatic gauge control(AGC) effect of the cold rolling mill for aluminum plate strip was studied in three modes of BISRA-AGC ,GM-AGC and DAGC .The mathematical models of the system were built ,and these pressure AGC were simulated by MATLAB/Simulink software .The simulation data and the experimental results show that DAGC control model could effectively improve the thickness control accuracy of cold rolling mill at the low cost .%采用BISRA-AGC , GM-AGC和DAGC三种压力AGC控制方式,研究铝板带材冷轧机的自动厚度控制效果。建立系统的数学模型,使用MATLAB/Simulink软件进行仿真模拟,通过对比三种压力AGC控制下系统的模拟数据及实验结果得出, DAGC模型控制系统能够以较低成本投入有效改善冷轧机厚度控制精度。

  10. The Intricate Role of Cold Gas and Dust in Galaxy Evolution at Early Cosmic Epochs

    Science.gov (United States)

    Riechers, Dominik Alexander; Capak, Peter; Carilli, Christopher; Walter, Fabian

    2015-08-01

    Cold molecular and atomic gas plays a central role in our understanding of early galaxy formation and evolution. It represents the material that stars form out of, and its mass, distribution, excitation, and dynamics provide crucial insight into the physical processes that support the ongoing star formation and stellar mass buildup. We will discuss the most recent progress in studies of gas-rich galaxies out to the highest redshifts through detailed investigations with the most powerful facilities across the electromagnetic spectrum, with a particular focus on new observations obtained with the Karl G. Jansky Very Large Array (VLA) and the Atacama Large (sub-) Millimeter Array (ALMA). These studies cover a broad range in galaxy properties, and provide a detailed comparison of the physical conditions in massive, dust-obscured starburst galaxies and star-forming active galactic nuclei hosts within the first billion years of cosmic time. Facilitating the impressive sensitivity of ALMA, this investigation also includes the first direct, systematic study of the star-forming interstellar medium, gas dynamics, and dust obscuration in (much less luminous and massive) "typical" galaxies at such early epochs. These new results show that "typical" z>5 galaxies are significantly metal-enriched, but not heavily dust-obscured, consistent with a decreasing contribution of dust-obscured star formation to the star formation history of the universe towards the earliest cosmic epochs.

  11. Precursor evolution and SCC initiation of cold-worked alloy 690 in simulated PWR primary water

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Ziqing; Kruska, Karen; Toloczko, Mychailo B.; Bruemmer, Stephen M.

    2017-03-27

    Stress corrosion crack initiation of two thermally-treated, cold-worked (CW) alloy 690 materials was investigated in 360oC simulated PWR primary water using constant load tensile (CLT) tests and blunt notch compact tension (BNCT) tests equipped with direct current potential drop (DCPD) for in-situ detection of cracking. SCC initiation was not detected by DCPD for the 21% and 31%CW CLT specimens loaded at their yield stress after ~9,220 h, however intergranular (IG) precursor damage and isolated surface cracks were observed on the specimens. The two 31%CW BNCT specimens loaded at moderate stress intensity after several cyclic loading ramps showed DCPD-indicated crack initiation after 10,400h exposure at constant stress intensity, which resulted from significant growth of IG cracks. The 21%CW BNCT specimens only exhibited isolated small IG surface cracks and showed no apparent DCPD change throughout the test. Interestingly, post-test cross-section examinations revealed many grain boundary (GB) nano-cavities in the bulk of all the CLT and BNCT specimens particularly for the 31%CW materials. Cavities were also found along GBs extending to the surface suggesting an important role in crack nucleation. This paper provides an overview of the evolution of GB cavities and will discuss their effects on crack initiation in CW alloy 690.

  12. Seasonal evolution of the Yellow Sea Cold Water Mass and its interactions with ambient hydrodynamic system

    Science.gov (United States)

    Li, Jianchao; Li, Guangxue; Xu, Jishang; Dong, Ping; Qiao, Lulu; Liu, Shidong; Sun, Pingkuo; Fan, Zhisong

    2016-09-01

    The Yellow Sea Cold Water Mass (YSCWM) is an important component of the hydrodynamic system in the South Yellow Sea (SYS). However, its intricate interactions with the ambient flows over long time scales are not fully understood. This paper presents the analysis of the data set obtained from a seabed-mounted Acoustic Doppler Current Profiler (ADCP) deployed for nearly 1 year in the western SYS. It allowed us to study the evolution of YSCWM, including the seasonal changes of tidal currents, near-inertial oscillations (NIOs), and the wind-driven currents due to typhoons and winter storms. Strong NIOs were found near the bottom of mixed layer and in the pycnocline with nearly opposite current directions, with maximum velocity of nearly 20 cm·s-1 in summer. The YSCWM can also inhibit the direct downward energy transport in the water column due to typhoons. Conversely, the hydrodynamic system also feeds back to influence the change of YSCWM. A large current shear (S) of 20 cm·s-1·m-1 is generated near the top of pycnocline. Generally, the intensity and depth of the pycnocline determine S's magnitude and vertical location, respectively. Based on the monthly averaged density profile data, the Richardson number and wavelet analysis, the NIOs are considered to be capable of inducing predominant shear instability around the pycnocline. However, the NIOs are not strong enough to influence the lower YSCWM. In addition, in autumn, each fortnightly spring tide corresponds with a bottom temperature increase of nearly 2°C, indicating that tidal currents are the leading hydrodynamic driving force to decline the YSCWM.

  13. Simulation of rolling friction in the working stands of wide-strip mills

    Science.gov (United States)

    Garber, E. A.; Samarin, S. N.; Traino, A. I.; Ermilov, V. V.

    2007-04-01

    The energy consumed for rolling friction in the interroll contact area in the working stands of cold-rolling and pinch-pass mils intended for the production of wide steel strips has been analyzed. The coefficients and power of rolling friction are obtained for the first time using the databases of the process control systems of operating mills and simulating these quantities. A statistically reliable regression relation is obtained between the coefficient of rolling friction and the significant parameters of rolling and skin rolling (i.e., the interroll force, the roll speed, and the roll body roughness). The power fraction consumed for rolling friction is found to reach 60 80% of the total power of the main drive of working stands for skin rolling and 30 50% for cold rolling. Therefore, it is necessary to take into account these power losses in designing mills and developing technological cold-rolling conditions.

  14. 冷轧不同微量化学状态Al-Mn-Fe-Si铝合金的等温退火%Isothermal annealing of cold-rolled Al-Mn-Fe-Si alloy with different microchemistry states

    Institute of Scientific and Technical Information of China (English)

    黄科; 李彦军; Knut MARTHINSEN

    2014-01-01

    Microstructural evolution of a cold-rolled Al−Mn−Fe−Si alloy during annealing was studied. Except the as-cast variant, two other different homogenizations were considered, one gave a high density of fine dispersiods providing a considerable Zener drag influencing the softening behavior while the other gave a lower density of coarser dispersoid structure providing a much smaller drag effect. The gradual microstructural evolutions during annealing for the three variants were captured by interrupting annealing at different time. Effects of microchemistry state on recrystallization kinetics, recrystallized grain structure and texture were characterized by EBSD. It is demonstrated that the actual softening kinetics, final microstructure and texture are a result of delicate balance between processing condition and microchemistry state. Strong concurrent precipitation takes place in the case with high concentration of Mn in solid solution, which suppresses nucleation and retards recrystallization and finally leads to grain structure of coarse elongated grains dominated by a P texture component together with a ND-rotated cube component. On the contrary, when solute content of Mn is low and pre-existing dispersoids are relatively coarser, faster recrystallization kinetics is exhibited together with an equiaxed grain structure with mainly cube texture.%通过3种不同热处理工艺使一种Al−Mn−Fe−Si合金获得了不同固溶液和不同尺寸及数量的弥散析出相,包括铸造态,一种富含高密度、细小、弥散相的状态,另外一种状态则仅有少量、相对粗大的弥散相。采用EBSD技术系统研究冷轧后退火过程中微观组织的演变以及初始组织状态对再结晶动力学、再结晶晶粒形貌和织构的影响。结果表明,再结晶动力学、最终微观组织和织构由加工条件和合金的初始组织和固溶度决定。高密度弥散析出相阻止形核,显著阻碍软化过程,最终

  15. Evaluation of diffusion and phase transformation at Ag/Al bimetal produced by cold roll welding%冷轧焊接制备Ag/Al双金属材料的扩散和相转变

    Institute of Scientific and Technical Information of China (English)

    Hossein OLIA; Mehrdad ABBASI; Seyed Hossein RAZAVI

    2012-01-01

    通过轧制Al条和Ag条制备Ag/Al双金属条.为使Al和Ag条之间发生冷焊,对表面进行处理并设置不同的轧制压下量.实验表明:发生冷焊的最小临界轧制厚度压下量为70%,相当于轧制形状因子0.1630.对双金属条进行均匀化退火,于400℃保温不同时间.利使用扫描电子显微镜观察Al/Ag界面,研究可能存在的硬脆相.通过EDS分析和线扫描分析退火时间对扩散距离和相转变的影响.在界面上Ag侧观察到一个扩散区,其宽度随退火时间的延长而增加.退火处理3h后在靠近界面处观察到一些δ相,而且随着退火时间的延长,δ相变得更粗、更连续.显微硬度测试表明:尽管通过均匀化退火生成δ相,界面硬度却有所降低.%Aluminum and silver strips were cold welded by rolling and a bimetallic strip was produced.To create cold weld between Al and Ag,mating surfaces were specially prepared and various rolling thickness reductions were applied.The minimum critical thickness reduction to begin cold weld was specified as 70% which equals 0.1630 critical rolling shape factors.The bimetallic strips were treated by diffusion annealing at 400 ℃ and various annealing time.The Al/Ag interface of strips was observed by scanning electron microscope to investigate the formation of hard and brittle probable phases.The effect of anneal time on diffusion distance and phase transformation was also analysed by EDS analysis and line scan.A diffusion region along the interface in the Ag side was observed and its width increased with prolonging annealing time.Some δ phases were detected close to the interface after anneal treating for 3 h and δ phase was thicker and more continuous by increasing annealing time.The microhardness measurement showed that in spite of formation ofδ phase due to diffusion annealing,the interface hardness was reduced.

  16. The inferred evolution of the cold gas properties of CANDELS galaxies at 0.5 < z < 3.0

    CERN Document Server

    Popping, G; Trager, S C; Somerville, R S; Dekel, A; Kassin, S A; Kocevski, D D; Koekemoer, A M; Faber, S M; Ferguson, H C; Galametz, A; Grogin, N A; Guo, Y; Lu, Y; van der Wel, A; Weiner, B J

    2015-01-01

    We derive the total cold gas, atomic hydrogen, and molecular gas masses of approximately 24 000 galaxies covering four decades in stellar mass at redshifts 0.5 < z < 3.0, taken from the CANDELS survey. Our inferences are based on the inversion of a molecular hydrogen based star formation law, coupled with a prescription to separate atomic and molecular gas. We find that: 1) there is an increasing trend between the inferred cold gas (HI and H2), HI, and H2 mass and the stellar mass of galaxies down to stellar masses of 10^8 Msun already in place at z = 3; 2) the molecular fractions of cold gas increase with increasing stellar mass and look-back time; 3) there is hardly any evolution in the mean HI content of galaxies at fixed stellar mass; 4) the cold gas fraction and relative amount of molecular hydrogen in galaxies decrease at a relatively constant rate with time, independent of stellar mass; 5) there is a large population of low-stellar mass galaxies dominated by atomic gas. These galaxies are very ga...

  17. Analysis for the Propagation of Edge Crack of Silicon Steel during Cold Rolling Process Based on GTN Damage Model%基于GTN模型的冷轧硅钢边部裂纹扩展研究

    Institute of Scientific and Technical Information of China (English)

    闫玉曦; 孙权; 陈建钧; 潘红良

    2012-01-01

    Edge crack is a kind of defects in the cold rolling process of silicon steel, causes rupture of the steel in the rolling mill and need to be removd. Hence, it is necessary to understand the formation of edge cracks The damage distribution, as well as the initiation and propagation of edge cracks around the tips of the precut notches during cold rolling process are investigated by using GTN damage model. The damage parameters fo, fc and fy are determined by tensile tests and scanning electron microscope(SEM) observation. The influence of various rolling parameters on damage distribution and crack length is studied by numerical simulation. The numerical results show that the GTN damage model is available to prediction the initiation and propagation of edge cracks during rolling process. Parametric study carry out in present work reveals that it is more possible to occur edge cracks at larger reduction, higher friction coefficient, smaller roll radius and stronger unit tension. The simulation and experimental results have a good agreement.%针对硅钢板容易在冷轧过程中形成边部裂纹,使用Gurson-Tvergaard-Needleman(GTN)微观损伤模型对带有边部微小缺口的硅钢板在冷轧过程中损伤分布以及裂纹的萌生和扩展进行研究.通过拉伸试验和扫描电镜观察分析得到材料的损伤参数fo、fc和fF,进而通过有限元软件ABAQUS模拟得到各轧制工艺参数对缺口尖端区域损伤分布及微裂纹萌生与扩展的影响,仿真与试验结果表明,在缺口尖端形成两条损伤带,最大损伤值随着压下率的增大而增大,同时裂纹长度随着压下率的增大而迅速增加;当工作辊半径较小时更加容易出现裂纹;沿着轧制方向缺口前侧的比后侧更容易产生裂纹,两侧的裂纹长度都随着摩擦因数的增大而增大;裂纹长度会随着张力的增大而明显增大.研究结果为轧制工艺参数的选择提供理论依据和参考.

  18. Microstructural evolution and formation mechanism of bimodal structure of 0.2% carbon steel subjected to the heavy-reduction controlled rolling process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyung-Won, E-mail: wonipark@iis.u-tokyo.ac.jp [Graduate School of Engineering, The University of Tokyo, Komaba 4-6-1, Meguro-ku, 153-8505 Tokyo (Japan); Shimojima, Kei [Graduate School of Engineering, The University of Tokyo, Komaba 4-6-1, Meguro-ku, 153-8505 Tokyo (Japan); Sugiyama, Sumio; Komine, Hisanao; Yanagimoto, Jun [Institute of Industrial Science, The University of Tokyo, Komaba 4-6-1, Meguro-ku, 153-8505 Tokyo (Japan)

    2015-01-29

    A heavy-reduction controlled rolling process with approximately 75% thickness reduction was carried out to investigate the microstructural evolution including texture development, focusing on the formation of a bimodal structure of 0.2% carbon steel with heating temperatures of 700, 800, 900, and 1000 °C. Upon increasing the heating temperature from 700 to 900 °C, the microstructure was refined and precipitates such as Fe{sub 3}C were uniformly distributed throughout the microstructure. For the microstructures control-rolled at heating temperatures of 900 and 1000 °C with average ferrite grain sizes of 1.34 and 1.63 μm, respectively, a bimodal structure could be observed by scanning electron microscopy (SEM), which was very similar to the result of a plane-strain compression (PSC) test. Moreover, the 900 and 1000 °C-heated specimens had less well developed textures primarily consisting of {113}–{4 4 11}〈110〉 and {332}〈113〉 components, which usually developed by the transformation (γ→α), and the 1000 °C-heated specimen exhibited various textures and a low intensity of the {100}〈011〉 component, which was generally transformed from the {100}〈001〉 component of the recrystallized austenite.

  19. Evolution of the microstructure, texture and creep properties of the 7075 aluminium alloy during hot accumulative roll bonding

    OpenAIRE

    Hidalgo-Manrique, P.; Cepeda-Jiménez, C.M.; Orozco-Caballero, Alberto; Ruano, Oscar Antonio; Carreño, Fernando

    2014-01-01

    The 7075 Al alloy was severely deformed at 350 °C by a 3:1 thickness reduction per pass accumulative roll bonding (ARB) process up to six passes. It was found that discontinuous recrystallisation occurs during the inter-pass annealing stages from the third pass on, attributable to the increment of the mean particle size during processing. As a consequence, the mean crystallite size did not decrease, but remained approximately constant at 440 nm along the present ARB process and the mean bound...

  20. Precipitation and Recrystallization of 3003 Cold-rolled Strip during Homogenizing Annealing%3003冷轧板均匀化退火过程中的析出和再结晶

    Institute of Scientific and Technical Information of China (English)

    胡冠奇; 李荣平; 刘宏伟; 毕书军; 袁文晓

    2011-01-01

    The influences on the second-phase particle precipitation and recrystallized grain size during homogenization annealing of twin-roll cast 3003 strips with different cold deformations were investigated by optical microscope and digital electric bridge. The results show that the number of fine second-phase particle precipitation reaches maximum at the recrystallization starting temperature and the size of inherent second-phase particle has important influence on recrystallization. The grain size is increased with increasing in cold deformation after homogenization, owing to the coarse inherent second-phase particle was broken during rolling process.%利用光学显微镜(OM)和数字电桥等手段,研究了均匀化退火温度对铸轧3003合金不同变形量冷轧板第二相粒子析出和再结晶晶粒大小的影响.结果表明,均匀化退火过程中,板料内部第二相粒子析出量在再结晶开始温度达到最大值.初生第二相粒子的大小对冷轧板再结晶有重要影响,随变形量增加,初生第二相粒子逐渐破碎,导致均匀化退火后板料晶粒尺寸随着变形量的增加而迅速增大.

  1. Evolution of magnetic phase at low aging temperature in a heavily cold-drawn stainless steel fiber

    Science.gov (United States)

    Yang, Shun-Tung; Hwang, Weng-Sing; Shyr, Tien-Wei; Cheng, I.-Lin

    2012-08-01

    The evolution of the magnetic phase upon aging at 300-520 °C in a heavily cold-drawn AISI 316L austenitic stainless steel fiber was studied using thermomagnetic analysis (TMA) and magnetic force microscopy with a heating stage. An increasing trend of magnetization from 50 °C to around 470 °C in the heating curves of TMA in austenitic stainless steels after a cold-drawing process was observed. No significant Ms temperature signal in the TMA curve at cooling indicated an increase in magnetization upon cooling period without significant phase transformation. A series of in situ magnetic force microscopy observations reveal a growth of the magnetic domain structure after aging at 300 °C for 2.5 h. Results show that the ferromagnetic increase during aging at lower annealing temperature resulted from the growth of martensite.

  2. Microstructure Evolution and Mechanical Properties of Al-TiB₂/TiC In Situ Aluminum-Based Composites during Accumulative Roll Bonding (ARB) Process.

    Science.gov (United States)

    Nie, Jinfeng; Wang, Fang; Li, Yusheng; Cao, Yang; Liu, Xiangfa; Zhao, Yonghao; Zhu, Yuntian

    2017-01-25

    In this study, a kind of Al-TiB₂/TiC in situ composite was successfully prepared using the melt reaction method and the accumulative roll-bonding (ARB) technique. The microstructure evolution of the composites with different deformation treatments was characterized using field emission scanning electron microscopy (FESEM) and a transmission electron microscope (TEM). The mechanical properties of the Al-TiB₂/TiC in situ composite were also studied with tensile and microhardness tests. It was found that the distribution of reinforcement particles becomes more homogenous with an increasing ARB cycle. Meanwhile, the mechanical properties showed great improvement during the ARB process. The ultimate tensile strength (UTS) and microhardness of the composites were increased to 173.1 MPa and 63.3 Hv after two ARB cycles, respectively. Furthermore, the strengthening mechanism of the composite was analyzed based on its fracture morphologies.

  3. Microstructure Evolution and Mechanical Properties of Al-TiB2/TiC In Situ Aluminum-Based Composites during Accumulative Roll Bonding (ARB) Process

    Science.gov (United States)

    Nie, Jinfeng; Wang, Fang; Li, Yusheng; Cao, Yang; Liu, Xiangfa; Zhao, Yonghao; Zhu, Yuntian

    2017-01-01

    In this study, a kind of Al-TiB2/TiC in situ composite was successfully prepared using the melt reaction method and the accumulative roll-bonding (ARB) technique. The microstructure evolution of the composites with different deformation treatments was characterized using field emission scanning electron microscopy (FESEM) and a transmission electron microscope (TEM). The mechanical properties of the Al-TiB2/TiC in situ composite were also studied with tensile and microhardness tests. It was found that the distribution of reinforcement particles becomes more homogenous with an increasing ARB cycle. Meanwhile, the mechanical properties showed great improvement during the ARB process. The ultimate tensile strength (UTS) and microhardness of the composites were increased to 173.1 MPa and 63.3 Hv after two ARB cycles, respectively. Furthermore, the strengthening mechanism of the composite was analyzed based on its fracture morphologies. PMID:28772467

  4. The combined effect of aging and accumulative roll bonding on the evolution of the microstructure and mechanical characteristics of an Al-0.2 wt % Zr alloy

    Science.gov (United States)

    Azad, B.; Semnani, H. M.; Borhani, E.

    2017-01-01

    This work is devoted to the effect of processes initiated by the combined action of aging (A) and accumulative roll bonding (ARB) on the evolution of the microstructure and the mechanical characteristics of an Al-0.2 wt % Zr alloy. Upon solution treatment (ST), followed by aging at temperatures of 350 and 450°C, the specimens were subjected to deformation to a degree of deformation of 80% using ARB. The evolution of the microstructure was examined using atomic force microscopy and the mechanical characteristics of the specimens were determined using tensile tests and Vickers microhardness measurements. The results have shown that, upon ten ARB cycles, the grain size decreased to 0.3, 0.4, and 0.32 μm in the specimens subjected to ST followed by ARB (ST-ARB), ST followed by A at a temperature of 350°C and ARB (350°C-A-ARB), and ST followed by A at a temperature of 450°C and ARB (450°C-A-ARB), respectively. This study has also shown that the combined use of preliminary A and subsequent ARB holds promise in enhancing the mechanical characteristics of the alloy due to precipitates that appear in the course of annealing. Fracture surfaces of the rolled specimens subjected to the tensile tests were examined using scanning electron microscopy. The results of these examinations have shown that in the specimens subjected to ST followed by ARB brittle fracture has been observed at the stage of the final ARB cycles, while in the A-ARB specimens cleavage facets (sites of fracture over the cleavage plane) and river lines have appeared on the fracture surfaces.

  5. 非离子乳化剂对冷轧油乳化稳定性的影响%Influence of Nonionic Emulsifier on Stability of Cold Rolling Emulsion

    Institute of Scientific and Technical Information of China (English)

    田田; 闫锋; 朱静; 李玲; 王相福

    2012-01-01

    在薄板冷轧过程中,轧制油的润滑性、稳定性是影响薄板质量的重要因素.辽河油田减侧线油与合成酯以质量比为7∶3的比例调合作为基础油,按一定比例加入不同种类的非离子复配乳化剂、极压抗磨剂、防锈剂、消泡剂和防腐剂,并加入体积分数为95%的水进行乳化,制备冷轧油乳化液.以我国现行乳化液使用行业标准为依据,着重考察非离子乳化剂中的酯类与醚类复配的乳化剂对冷轧油乳化稳定性的影响.结果表明,对于同一种基础油,酯类和醚类的非离子复配乳化剂的乳化稳定性比单一种类的酯类或醚类复配体系要好;最终产品符合乳化液行业使用标准.%In the process of producing cold -rolled sheet, the properties of rolling oil, such as lubrication, and emulsion stability are essential factors. This study selected pentaerythrite oleate and mineral from LiaoHe as the base oil. Then adding in diffrernt kinds of nonionic complex emulsifying agent, EP -antiwear additive, antirusting agent, foam suppressor and preservative to the water of 90% ~95 5/o, and emulsifying. This experiment used our current industry standard for the reasearch on emulsion stability. The results show that the stability of cold rolling emulsion of the esters and ethers nonionic emulsifier to the base oil is better than a single species of esters or ethers compound system; Final products meet requirements of the emulsion industry standard: After 24 h, 5% emulsion oil separating soap volume is 1. 0 mL, 2% emulsion oil the bubbles are completely eliminated in 5 min.

  6. 模压形变和冷轧复合处理对Cu-35Zn合金组织和性能的影响%Effects of constrained groove pressing plus cold rolling on microstructure and mechanical properties of Cu-35Zn alloy

    Institute of Scientific and Technical Information of China (English)

    彭开萍; 牟雪萍

    2013-01-01

    Cu-35Zn alloy was deformed by ten passes constrained groove pressing (CGP) firstly,and then by cold rolling with 10%-30% strain.The microstructure and properties of Cu-35Zn alloy after processed by CGP and cold rolling were studied.The results show that the grains of Cu-35Zn alloy get fined after CGP.The number of deformation twins in the sample increases and the homogeneity of the sample is also improved by subsequent cold rolling.With the increasing of cold rolling strain,the hardness and strength of Cu-35Zn alloy after the deformation of CGP plus cold rolling are increased,but the elongation decreases.%采用模压形变技术对Cu-35Zn合金进行十道次的模压形变,随后再进行10% ~ 30%不同应变量的冷轧,研究Cu-35Zn合金经复合处理后的微观组织和力学性能.结果表明,Cu-35Zn合金经模压形变后可以细化晶粒,进一步冷轧可以使试样获得更多的孪晶组织;组织均匀性提高.复合处理后材料的强度和硬度随着冷轧应变量的增大而增大,但伸长率下降.

  7. Recrystallization of deformed copper - kinetics and microstructural evolution

    DEFF Research Database (Denmark)

    Lin, Fengxiang

    The objective of this study is to investigate the recrystallization kinetics and microstructural evolution in copper deformed to high strains, including copper deformed by cold-rolling and copper deformed by dynamic plastic deformation (DPD). Various characterization techniques were used, including...

  8. Microstructure Evolution and Mechanical and Corrosion Behavior of Accumulative Roll Bonded Mg-2%Zn/Al-7075 Multilayered Composite

    Science.gov (United States)

    Anne, Gajanan; Ramesh, M. R.; Shivananda Nayaka, H.; Arya, Shashi Bhushan; Sahu, Sandeep

    2017-02-01

    Multilayered composite of Mg-2%Zn/Al-7075 was developed by accumulative roll bonding (ARB) of wrought Mg-2%Zn and aluminum 7075 alloy. The Mg-2%Zn/Al-7075 multilayered composite exhibited density of 2295 kg/m3 and an average grain size of 1 and 1.3 μm in Mg-2%Zn and Al-7075 layers, respectively. A thorough microstructural characterization was performed on the composites by scanning electron microscope, electron backscatter diffraction (EBSD), transmission electron microscope and phase analysis by x-ray diffraction. In addition, mechanical properties were evaluated by microhardness and tensile tests. Corrosion behavior of the multilayered composite was examined using electrochemical polarization test. EBSD analysis showed the presence of ultrafine grains with high-angle grain boundaries. The composite exhibited a significant improvement in ultimate tensile strength ( 1.82 times) and elongation ( 1.5 times) as compared with Mg-2%Zn alloy, after four-pass ARB process.

  9. Quantitative analysis of the recrystallized textures of cold-rolled 430 stainless steel during high-temperature annealing%430不锈钢冷轧板高温退火过程中再结晶织构的定量分析

    Institute of Scientific and Technical Information of China (English)

    王乃帅; 张雄; 温治; 豆瑞锋; 李志强

    2014-01-01

    在750、800、825和850℃温度下,利用Gleeble1500热模拟试验机对430不锈钢冷轧薄板的等温退火过程进行了详细的实验研究,分析了退火过程中再结晶织构和组织的变化规律,并对关键织构体积分数的演变进行了定量分析。结果发现:随着退火过程的进行,α取向线上的织构强度逐渐减弱,而酌取向线上的织构强度则略有加强,并保持在较高的值;再结晶过程中,{111}和{112}织构的体积分数逐渐降低,而{100}和随机取向晶粒的体积分数逐渐增加。定量分析表明,退火温度越低,完全再结晶后材料内部关键织构的体积分数越偏离冷轧态。最后,针对{111}、{112}、{100}和随机取向织构的体积分数在再结晶过程中的演变规律,建立了JMAK型再结晶织构演变动力学模型。%ABSTRACT Variations in the recrystallized texture and microstructure of cold-rolled 430 stainless steel during isothermal annealing were investigated on a Gleeble-1500 thermal-mechanic simulator at 750, 800, 825 and 850℃, and the evolution of main textures was analyzed quantitatively. As annealing proceeds, the intensity of α-fiber orientation components decreases, but the intensity of γ-fiber components increases slightly and maintains at a higher value. The volume fraction of{111} and{112} decreases as recrystal-lization proceeds, while the volume fraction of{100} and random orientation textures increases. Compared with the cold-rolled state, it is observed that the volume fraction of main textures has greater changes in annealing at low temperature than at high temperature. Finally, variations in the volume fraction of{111},{112} ,{100} and random orientation textures during recrystallization were described by a JMAK kinetics model.

  10. Microfossils, a Key to Unravel Cold-Water Carbonate Mound Evolution through Time: Evidence from the Eastern Alboran Sea.

    Directory of Open Access Journals (Sweden)

    Claudio Stalder

    Full Text Available Cold-water coral (CWC ecosystems occur worldwide and play a major role in the ocean's carbonate budget and atmospheric CO2 balance since the Danian (~65 m.y. ago. However their temporal and spatial evolution against climatic and oceanographic variability is still unclear. For the first time, we combine the main macrofaunal components of a sediment core from a CWC mound of the Melilla Mounds Field in the Eastern Alboran Sea with the associated microfauna and we highlight the importance of foraminifera and ostracods as indicators of CWC mound evolution in the paleorecord. Abundances of macrofauna along the core reveal alternating periods dominated by distinct CWC taxa (mostly Lophelia pertusa, Madrepora oculata that correspond to major shifts in foraminiferal and ostracod assemblages. The period dominated by M. oculata coincides with a period characterized by increased export of refractory organic matter to the seafloor and rather unstable oceanographic conditions at the benthic boundary layer with periodically decreased water energy and oxygenation, variable bottom water temperature/density and increased sediment flow. The microfaunal and geochemical data strongly suggest that M. oculata and in particular Dendrophylliidae show a higher tolerance to environmental changes than L. pertusa. Finally, we show evidence for sustained CWC growth during the Alleröd-Younger-Dryas in the Eastern Alboran Sea and that this period corresponds to stable benthic conditions with cold/dense and well oxygenated bottom waters, high fluxes of labile organic matter and relatively strong bottom currents.

  11. Tracking trails by cracking codes : Molecular biogeography and evolution of benthic cold-water seaweeds

    NARCIS (Netherlands)

    van Oppen, Madeleine Josephine Henriette

    1995-01-01

    The main objective of this thesis was to examine the evolutionary diversification and biogeography of some polar and cold-temperatsee aweeds. Distribution patterns and dispersal routes were investigated in three species exhibiting a bipolar disjunction and one with an amphi-Atlantic distribution, by

  12. Cold Spring Harbor symposia on quantitative biology: Volume 52, Evolution of catalytic function

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    This document contains 97 papers presented at the symposium. The primary topic was the evolution of the catalytic function. Speakers discussed the evolution of genetic apparatus, the primordial soup, the anatomy of RNA, RNA templates, protein assembly, protein structure, cofactors, ribosomes, exons, and introns. Individual papers were processed separately for the data base. (TEM)

  13. Thermovision systems used to improve a technological process for hot-rolled copper and brass strips

    Directory of Open Access Journals (Sweden)

    Z. Rdzawski

    2009-10-01

    Full Text Available Purpose: This paper contains description made on thermovision testing with the use of Inframetrics 760B system. Measurements were executed on the surface of a heat furnace and also on the surface of material heated before and hot-rolled. The results of the investigations in a form of thermograpic pictures were taken down in working environment.Design/methodology/approach: The purpose of this research was to evaluate technological process of heating cooper and brass cakes, and hot-rolled strip in special passes assessment of the temperature modification. For basic criterion estimation of these processes, the maintenance at the demanded final rolling temperature in order to keep up adequate structure and narrow range of mechanical properties variation was accepted.Findings: The process of heating charge material is carried through in order to facilitate its machining in a rolling process. When the material does not obtain the adequate temperature or does not become uniformly heated, internal stresses which cause appearance of the rims of fracture and occurrence of other defects in structure appear in cold rolling, as the next. Because of this there is a need of temperature controlling. Research limitations/implications: If a temperature profile on heated to a hot-rolled cakes is not uniform and does not reach a given level, this can mean forming some defects, which can be revealed during a hot-rolled process, relatively during following technological operations leading to a quality decrease and in a consequence to product disqualificationOriginality/value: The use of thermovision system in processes of heating cakes evolution and also hot-rolling. These research enable a condition control of thermal furnace and hot-roll processes.

  14. Microstructural evolution of aluminium/Al–Ni–Sm glass forming alloy laminates obtained by Controlled Accumulative Roll Bonding

    Energy Technology Data Exchange (ETDEWEB)

    Anghelus, Adrian, E-mail: anghelus.adrian@yahoo.com; Avettand-Fènoël, Marie-Noëlle, E-mail: marie-noelle.avettand-fenoel@univ-lille1.fr; Cordier, Catherine, E-mail: catherine.cordier@univ-lille1.fr; Taillard, Roland, E-mail: roland.taillard@univ-lille1.fr

    2015-05-15

    Highlights: • Elaboration of a UFG material by controlled ARB of Al/glass forming alloy multilayers. • Effect of the crystalline or amorphous nature of the reinforcement on the formability. • Investigation of the thermo-mechanical stability of the metallic glass. - Abstract: The current work deals with the early steps of the unprecedented elaboration of aluminium/Al based glass forming alloy laminates by only accumulative rolling at room temperature. The Al{sub 1−(x+y)}Ni{sub x}Sm{sub y} metallic glass forming alloy was introduced either in its original amorphous state or after total crystallization. This change of atomic structure, and therefore of both thermal and thermo-mechanical stability and mechanical behaviour, is shown to govern at once the processing parameters, the uniformity of the laminates microstructure and the bond strength at the matrix-reinforcement interfaces. The potential of the process so as to synthesize composite materials with a stable ultrafine structure is finally outlined.

  15. Global dynamic evolution of the cold plasma inferred with neural networks

    Science.gov (United States)

    Zhelavskaya, Irina; Shprits, Yuri; Spasojevic, Maria

    2017-04-01

    The electron number density is a fundamental parameter of plasmas and is critical for the wave-particle interactions. Despite its global importance, the distribution of cold plasma and its dynamic dependence on solar wind conditions remains poorly quantified. Existing empirical models present statistical averages based on static geomagnetic parameters, but cannot reflect the dynamics of the highly structured and quickly varying plasmasphere environment, especially during times of high geomagnetic activity. Global imaging provides insights on the dynamics but quantitative inversion to electron number density has been lacking. We propose an empirical model for reconstruction of global dynamics of the cold plasma density distribution based only on solar wind data and geomagnetic indices. We develop a neural network that is capable of globally reconstructing the dynamics of the cold plasma density distribution for L shells from 2 to 6 and all local times. We utilize the density database obtained using the NURD algorithm [Zhelavskaya et al., 2016] in conjunction with solar wind data and geomagnetic indices to train the neural network. This study demonstrates how the global dynamics can be reconstructed from local in-situ observations by using machine learning tools. We describe aspects of the validation process in detail and discuss the selected inputs to the model and their physical implication.

  16. Properties, Microstructures and Precipitate Morphology of Hot-rolled Interstitial-Free (IF) Steel Sheets

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to simplify production process and to decrease production cost of thicker cold-rolled IFsteel sheets for deep drawing applications, a new hot-rolled IF steel sheet is developed through hot-rolling in α region. In this paper, properties, microstructures and precipitate morphology of hot-rolled IF steel sheets are described..

  17. Rolling Uphill

    Science.gov (United States)

    Cross, Rod

    2017-01-01

    In a recent letter to this journal, Mungan noted that translational energy can be converted into gravitational potential energy when an object is projected vertically, but rotational energy is not usually converted in this manner. As an exception, he gave an example where "a ball initially rolling without slipping will travel higher up a…

  18. [Comporison Sduty of Microstructure by Metallographicalk on the Polarized Light and Texture by XRD of CC 5083 and CC 5182 Aluminium Alloy after Cold Rolling and Recrystallization].

    Science.gov (United States)

    Chen, Ming-biao; Li, Yong-wei; Tan, Yuan-biao; Ma, Min; Wang, Xue-min; Liu, Wen-chang

    2015-03-01

    At present the study of relation between microstructure, texture and performance of CC 5083 aluminium alloy after cold tolling and recrystallization processes is still finitude. So that the use of the CC 5083 aluminium alloy be influenced. Be cased into electrical furnace, hot up with unlimited speed followed the furnace hot up to different temperature and annealed 2h respectively, and be cased into salt-beth furnace, hot up quickly to different temperature and annealed 30 min respectively for CC 5083 and CC 5182 aluminum alloy after cold roling with 91.5% reduction. The microstructure be watched use metallographic microscope, the texture be inspected by XRD. The start temperature of recrystallization and grain grow up temperature within annealing in the electric furnace of CC 5083 aluminum alloy board is 343 degrees C, and the shap of grain after grow up with long strip (the innovation point ); The start temperature of recrystallization within annealling in the salt bath furnace of CC 5083 is 343 degrees C. The start temperature and end temperature of recrystallization within annealling of CC 5083 and CC 5182 aluminum alloy is 371 degrees C. The grain grow up outstanding of cold rooled CC 5152 aluminum alloy after annealed with 454 degrees C in the electric furnace and salt bath furnace. The start temperature of grain grow up of CC 5083 alluminurn alloy annealed in the electric furnace and salt bath furnace respectively is higher than the start temperature of grain grow up of CC 5182 alluminum alloy annealed in the electric furnace and salt bath furnace respectively. The strat temperature of recrystallization grain grow up is higher than which annealled with other three manner annealing process. The recrystallization temperature of CC 5182 annealed in the salt bath furnace is higher than which annealed in the electric furnace. The recrystallization temperature of the surface layer of CC 5083 and CC 5182 aluminum alloy is higher than the inner layer (the innovation

  19. Galactic Cold Cores VII: Filament Formation and Evolution - Methods & Observational Constraints

    CERN Document Server

    Rivera-Ingraham, A; Juvela, M; Montillaud, J; Men'shchikov, A; Malinen, J; Pelkonen, V -M; Marston, A; Martin, P G; Pagani, L; Paladini, R; Paradis, D; Ysard, N; Ward-Thompson, D; Bernard, J -P; Marshall, D J; Montier, L; Tóth, V

    2016-01-01

    The association of filaments with protostellar objects has made these structures a priority target in star formation studies. The datasets of the Herschel Galactic Cold Cores Key Programme allow for a statistical study of filaments with a wide range of intrinsic and environmental characteristics. Characterisation of this sample can be used to identify key physical parameters and quantify the role of environment in the formation of supercritical filaments. Filaments were extracted from fields at DMcrit/2 may become supercritical and form stars. This translates into a need for filaments to become at least moderately self-gravitating in order to undergo localised star formation or become star-forming filaments.

  20. Development of TRIP-Aided Lean Duplex Stainless Steel by Twin-Roll Strip Casting and Its Deformation Mechanism

    Science.gov (United States)

    Zhao, Yan; Zhang, Weina; Liu, Xin; Liu, Zhenyu; Wang, Guodong

    2016-12-01

    In the present work, twin-roll strip casting was carried out to fabricate thin strip of a Mn-N alloyed lean duplex stainless steel with the composition of Fe-19Cr-6Mn-0.4N, in which internal pore defects had been effectively avoided as compared to conventional cast ingots. The solidification structure observed by optical microscope indicated that fine Widmannstatten structure and coarse-equiaxed crystals had been formed in the surface and center, respectively, with no columnar crystal structures through the surface to center of the cast strip. By applying hot rolling and cold rolling, thin sheets with the thickness of 0.5 mm were fabricated from the cast strips, and no edge cracks were formed during the rolling processes. With an annealing treatment at 1323 K (1050 °C) for 5 minutes after cold rolling, the volume fractions of ferrite and austenite were measured to be approximately equal, and the distribution of alloying elements in the strip was further homogenized. The cold-rolled and annealed sheet exhibited an excellent combination of strength and ductility, with the ultimate tensile strength and elongation having been measured to be 1000 MPa and 65 pct, respectively. The microstructural evolution during deformation was investigated by XRD, EBSD, and TEM, indicating that ferrite and austenite had different deformation mechanisms. The deformation of ferrite phase was dominated by dislocation slipping, and the deformation of austenite phase was mainly controlled by martensitic transformation in the sequence of γ→ ɛ-martensite→ α'-martensite, leading to the improvement of strength and plasticity by the so-called transformation-induced plasticity (TRIP) effect. By contrast, lean duplex stainless steels of Fe-21Cr-6Mn-0.5N and Fe-23Cr-7Mn-0.6N fabricated by twin-roll strip casting did not show TRIP effects and exhibited lower strength and elongation as compared to Fe-19Cr-6Mn-0.4N.

  1. Textures variation of 3104 aluminum alloy sheets under different rolling conditions

    Institute of Scientific and Technical Information of China (English)

    胡卓超; 刘沿东; 张德芬; 左良; 王福

    2003-01-01

    The textures variation of 3104 aluminum alloy sheets during hot rolling, cold rolling, transverse cold rolling and cross shear rolling were investigated by means of X-ray ODF analysis. The results show that the main texture component {100}〈011〉 becomes stronger with the increase of hot rolling reduction. The cold rolling textures are composed of typical "copper-type" texture components C{112}〈111〉, S{123}〈634〉, R/S{124}〈211〉, B{110}〈112〉 and G{110}〈001〉, the orientation intensities increase with increasing cold rolling reduction. Compared to the conventional cold rolling with the same amount reduction, the transverse rolling reduces the orientation intensities of each cold rolling textures components, and strengthens the {001}〈110〉 and {110}〈uvw〉 texture components. During cross shear rolling process, notable difference of intensity of cold rolling textures components were observed from the slow roller side to the fast roller.

  2. Evolution and interaction of twins, dislocations and stacking faults in rolled α-brass during nanostructuring at sub-zero temperature

    Directory of Open Access Journals (Sweden)

    Barna Roy

    2014-06-01

    Full Text Available The effect of cryorolling (CR strain at 153 K on the evolution of structural defects and their interaction in α−brass (Cu–30 wt.% Zn during nanostructuring has been evaluated. Even though the lattice strain increases up to 2.1 × 10−3 at CR strain of 0.6 initially, but it remains constant upon further rolling. Whereas, the twin density (β increases to a maximum value of 5.9 × 10−3 at a CR strain of 0.7 and reduces to 1.1 × 10−5 at 0.95. Accumulation of stacking faults (SFs and lattice disorder at the twin boundaries causes dynamic recrystallization, promotes grain refinement and decreases the twin density by forming subgrains. Detailed investigations on the formation and interaction of defects have been done through resistivity, positron lifetime and Doppler broadening measurements in order to understand the micro-mechanism of nanostructuring at sub-zero temperatures.

  3. Adaptive functional evolution of leptin in cold-adaptive pika family

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Aresearch team led by Prof.ZHAO Xinquan with the CAS Northwest Institute of Plateau Biology has put forward the viewpoint for the first time that adaptive functional evolution may occur in the leptin protein of the pika (Ochotona) family, a typical coldadaptive mammal.

  4. Synchrotron high energy X-ray diffraction study of microstructure evolution of severely cold drawn NiTi wire during annealing

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Cun; Aoun, Bachir; Cui, Lishan; Liu, Yinong; Yang, Hong; Jiang, Xiaohua; Cai, Song; Jiang, Daqiang; Liu, Zunping; Brown, Dennis E.; Ren, Yang

    2016-01-01

    Microstructure evolution of a cold-drawn NiTi shape memory alloy wire was investigated by means of in-situ synchrotron high-energy X-ray diffraction during continuous heating. The cold-drawn wire contained amorphous regions and nano-crystalline domains in its microstructure. Pair distribution function analysis revealed that the amorphous regions underwent structural relaxation via atomic rearrangement when heated above 100 °C. The nano-crystalline domains were found to exhibit a strong cold work induced lattice strain anisotropy having a preferential <111> fiber orientation along the wire axial direction. The lattice strain anisotropy systematically decreased upon heating above 200 °C, implying a structural recovery. A broad conical texture was formed in the wire specimen after crystallization similar in detail to the initial <111> texture axial orientation of the nano-crystalline domains produced by the severe cold wire drawing deformation.

  5. A Trend Between Cold Debris Disk Temperature and Stellar Type: Implications for the Formation and Evolution of Wide-Orbit Planets

    CERN Document Server

    Ballering, Nicholas P; Su, Kate Y L; Montiel, Edward

    2013-01-01

    Cold debris disks trace the limits of planet formation or migration in the outer regions of planetary systems, and thus have the potential to answer many of the outstanding questions in wide-orbit planet formation and evolution. We characterized the infrared excess spectral energy distributions of 174 cold debris disks around 546 main-sequence stars observed by both Spitzer IRS and MIPS. We found a trend between the temperature of the inner edges of cold debris disks and the stellar type of the stars they orbit. This argues against the importance of strictly temperature-dependent processes (e.g. non-water ice lines) in setting the dimensions of cold debris disks. Also, we found no evidence that delayed stirring causes the trend. The trend may result from outward planet migration that traces the extent of the primordial protoplanetary disk, or it may result from planet formation that halts at an orbital radius limited by the efficiency of core accretion.

  6. Microstructural evolution of aluminum alloy 3003 during annealing

    Institute of Scientific and Technical Information of China (English)

    WU Wen-xiang; ZHANG Xin-ming; SUN De-qin; HU Guo-qiang; LIU Guo-jin

    2006-01-01

    The microstructural evolution of cold-rolled aluminum alloy 3003 during annealing was investigated by means of micro-hardness measurement, electrical resistivity measurement, optical microscopy and transmission electron microscopy. The interaction of recrystallization and precipitation of aluminum alloy 3003 was also discussed. The results show that the recrystallized grain size of cold-rolled aluminum alloy 3003 is strongly affected by precipitation during annealing. When precipitation occurs prior to recrystallization at low temperature(300 ℃), the grain structure becomes coarse, and the precipitation process is affected by the presence of lattice defects, i.e. high cold reduction results in a large number of precipitates. When annealing at 500 ℃, however, for the recrystallization is prior to precipitation, the precipitation is independent of cold deformation reduction and a fine, equiaxed grain structure is obtained.

  7. Evolution of cold-tolerant fungal symbionts permits winter fungiculture by leafcutter ants at the northern frontier of a tropical ant-fungus symbiosis.

    Science.gov (United States)

    Mueller, Ulrich G; Mikheyev, Alexander S; Hong, Eunki; Sen, Ruchira; Warren, Dan L; Solomon, Scott E; Ishak, Heather D; Cooper, Mike; Miller, Jessica L; Shaffer, Kimberly A; Juenger, Thomas E

    2011-03-08

    The obligate mutualism between leafcutter ants and their Attamyces fungi originated 8 to 12 million years ago in the tropics, but extends today also into temperate regions in South and North America. The northernmost leafcutter ant Atta texana sustains fungiculture during winter temperatures that would harm the cold-sensitive Attamyces cultivars of tropical leafcutter ants. Cold-tolerance of Attamyces cultivars increases with winter harshness along a south-to-north temperature gradient across the range of A. texana, indicating selection for cold-tolerant Attamyces variants along the temperature cline. Ecological niche modeling corroborates winter temperature as a key range-limiting factor impeding northward expansion of A. texana. The northernmost A. texana populations are able to sustain fungiculture throughout winter because of their cold-adapted fungi and because of seasonal, vertical garden relocation (maintaining gardens deep in the ground in winter to protect them from extreme cold, then moving gardens to warmer, shallow depths in spring). Although the origin of leafcutter fungiculture was an evolutionary breakthrough that revolutionized the food niche of tropical fungus-growing ants, the original adaptations of this host-microbe symbiosis to tropical temperatures and the dependence on cold-sensitive fungal symbionts eventually constrained expansion into temperate habitats. Evolution of cold-tolerant fungi within the symbiosis relaxed constraints on winter fungiculture at the northern frontier of the leafcutter ant distribution, thereby expanding the ecological niche of an obligate host-microbe symbiosis.

  8. Computer-aided analysis and design of the shape rolling process for producing turbine engine airfoils

    Science.gov (United States)

    Lahoti, G. D.; Akgerman, N.; Altan, T.

    1978-01-01

    Mild steel (AISI 1018) was selected as model cold rolling material and Ti-6A1-4V and Inconel 718 were selected as typical hot rolling and cold rolling alloys, respectively. The flow stress and workability of these alloys were characterized and friction factor at the roll/workpiece interface was determined at their respective working conditions by conducting ring tests. Computer-aided mathematical models for predicting metal flow and stresses, and for simulating the shape rolling process were developed. These models utilized the upper bound and the slab methods of analysis, and were capable of predicting the lateral spread, roll separating force, roll torque, and local stresses, strains and strain rates. This computer-aided design system was also capable of simulating the actual rolling process, and thereby designing the roll pass schedule in rolling of an airfoil or a similar shape.

  9. 冷轧热镀锌镀层厚度控制系统的开发与应用%Development and application of coating thickness control system for cold rolling continuous galvanizing line

    Institute of Scientific and Technical Information of China (English)

    费静; 张岩; 王军生; 秦大伟; 侯永刚; 许寒冰

    2016-01-01

    在冷轧连续热镀锌生产线上,热镀锌镀层厚度的控制水平将直接影响到热镀锌板的产品质量、成本和市场竞争力。以鞍钢连续热镀锌生产线为背景,对冷轧热镀锌带钢的镀层厚度进行精确控制研究,利用有限元分析软件FLUENT对气刀吹锌过程进行数值模拟,分析影响镀层厚度精度的主要因素,建立镀层厚度自动控制系统的核心模型,提出气刀压力前馈控制和Smith预估补偿反馈控制方法,采用LABVIEW软件开发镀层厚度控制系统,实现镀层厚度精确控制。生产数据结果表明,控制系统的应用降低镀层厚度偏差,取得了较好的控制效果。通过镀层厚度自动控制系统的投入运行,不仅满足企业提高产品表面质量的需求,而且对节约成本、降低镀锌原料消耗具有重要意义。%For the cold rolling continuous galvanizing line,the control level of the coating thickness has a direct effect on the product quality,the cost and the market competition of hot galvanized sheet. Based on the background of Ansteel continuous galvanizing line,the current study mainly involved the research on the precise control of zinc coating thick-ness of cold-rolled sheet.The main factor influencing the precision of coating thickness was analyzed by means of the software FLUENT for the numerical simulation in gas-jet wiping process.The key model of coating thickness control sys-tem has been built with the adoption of air knife pressure feedforward control and Smith predictive compensation control methods. The coating thickness precise control was realized by adopting the software LABVIEW for the system develop-ment. Production results show that the application of the control system reduced the deviation of coating thickness and obtained well control effect. The application of coating thickness automatic control system not only meets the demand of improving product surface quality,but also provides an

  10. Individual Grain Orientation and Heterogeneous Deformation in Cold-deformed Interstitial-Free Sheet Steel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The cold rolling deformation textural evolution of an interstitial-free (IF) steel sheet is investigated by experiment and simulation. The microstructure of the IF steel is observed by transmission electron microscopy (TEM). The relationship between the deformation behavior of individual grain and the grain orientation are connected by Taylor factor M. The results show that the grains with higher Taylor factor are deformed slighter than those with lower ones. By considering the heterogeneous deformation, the texture simulation result can be greatly improved.

  11. Causes Analysis of Spalling of Backup Roll Bearing and Its Countermeasures in 1220mm Cold Tandem Mill%1220mm轧机支撑辊轴承外圈裂纹剥落分析及对策

    Institute of Scientific and Technical Information of China (English)

    段泉义; 徐俊; 程其华; 姚寿军

    2012-01-01

    To serious situation of backup roll bearing no-normal scrapped of 1220mm cold tandem mill of Baosteel, the causes were analyzed from lubrication and sealing. Therefore, some countermeasures were applied, including increasing oil level of lubrication oil tank from 30% to 70%~80%, shortening cycles of oil and water separation, changing cycles of seal replacement from 3~6 months to 3 months, strengthening bearing statue tracking and maintenance, and the number of support roller bearing scrapped due to the outer ring crack spalling was significantly reduced.%针对宝山钢铁股份有限公司冷轧薄板厂1220mm冷连轧机组支撑辊轴承非正常报废情况较为严重的问题,结合现场实际,从润滑、密封等多个角度分析了引起冷轧支撑辊轴承外圈裂纹剥落的深层原因,通过将润滑油油箱液位由30%增加到70%~80%,缩短润滑油的油水分离周期,将密封圈更换周期由原来的3~6个月改为固定的3个月,加强轴承状态跟踪及管理维护,使支撑辊轴承因外圈裂纹剥落而报废的数量明显降低.

  12. Reconstruction of a Supporting Roller Bearing Sealing System of Cold Rolling Equipment%某冷轧设备支撑辊轴承密封系统的改造

    Institute of Scientific and Technical Information of China (English)

    王文虎; 曾军林

    2015-01-01

    通过对某冷轧设备支撑辊轴承密封系统失效原因的分析,提出一种由防尘防垢密封、金属迷宫密封、骨架水封和骨架油封构成的组合密封方案,其中防尘防垢密封可防止外部乳化液、冷却水进入支撑辊;骨架水封与支撑环起到封油和防水、防切削液等进入的作用;骨架油封可有效防止密封内部油液的泄漏。改造后的密封系统密封效果良好,使用寿命大大延长。%Through the analysis of failure reasons of a supporting roller bearing sealing system for cold rolling equip-ment,a combination sealing solution composed of dustproof and anti-fouling seal,metal labyrinth seal,skeleton water seal and skeleton oil seal was proposed.The dustproof and anti-fouling seal can prevent external emulsion and cooling water en-tering the support rollers,the skeleton water seal and support ring act as sealing oil and preventing the water and cutting fluid entering the support rollers,and skeleton oil seal can effectively prevent the internal oil leakage.After transformation, the sealing system has good sealing effect,and service life is greatly extended.

  13. MICROSTRUCTURE AND PROPERTIES OF 600 MPa GRADE COLD ROLLED DUAL-PHASE STEEL%600MPa级含钒冷轧双相钢的组织性能研究

    Institute of Scientific and Technical Information of China (English)

    罗娟娟; 史文; 黄群飞; 李麟

    2011-01-01

    Cold rolled low carbon Si-Mn containing V dual phase steels of 600 Mpa grade were exploited in laboratory. The microstructure and property of tested steels after continuous annealing were measured. The results showed that the tested steels which had good mechanical properties could be obtained by annealing at 800 ℃, over-ageing at 300 ℃. After heat treatment, the yield strength was 358 Mpa, the tensile strength was 637 Mpa, the elongation and BH value reached 23.7% and 55 Mpa respectively. V element had two kinds of existent states, one was precipitate in ferrite, and another one was solute in ferrite, the main roles of vanadium in dual-phase steel was precipitation strength and refining grain size.%在实验室试制600 MPa级低碳Si-Mn含钒冷轧双相钢,研究了连续退火后试验钢的组织和力学性能.结果表明:经800℃保温,300℃过时效处理,可以获得综合力学性能优良的冷轧双相钢,其屈服强度为358 MPa,抗拉强度为637 MPa,伸长率达到了23.7%,BH值为55 MPa;钢中V主要以析出物和在铁素体中以固溶态两种状态存在,主要起到析出强化和细化晶粒的作用.

  14. Biological feedbacks as cause and demise of the Neoproterozoic icehouse: astrobiological prospects for faster evolution and importance of cold conditions.

    Directory of Open Access Journals (Sweden)

    Pekka Janhunen

    Full Text Available Several severe glaciations occurred during the Neoproterozoic eon, and especially near its end in the Cryogenian period (630-850 Ma. While the glacial periods themselves were probably related to the continental positions being appropriate for glaciation, the general coldness of the Neoproterozoic and Cryogenian as a whole lacks specific explanation. The Cryogenian was immediately followed by the Ediacaran biota and Cambrian Metazoan, thus understanding the climate-biosphere interactions around the Cryogenian period is central to understanding the development of complex multicellular life in general. Here we present a feedback mechanism between growth of eukaryotic algal phytoplankton and climate which explains how the Earth system gradually entered the Cryogenian icehouse from the warm Mesoproterozoic greenhouse. The more abrupt termination of the Cryogenian is explained by the increase in gaseous carbon release caused by the more complex planktonic and benthic foodwebs and enhanced by a diversification of metazoan zooplankton and benthic animals. The increased ecosystem complexity caused a decrease in organic carbon burial rate, breaking the algal-climatic feedback loop of the earlier Neoproterozoic eon. Prior to the Neoproterozoic eon, eukaryotic evolution took place in a slow timescale regulated by interior cooling of the Earth and solar brightening. Evolution could have proceeded faster had these geophysical processes been faster. Thus, complex life could theoretically also be found around stars that are more massive than the Sun and have main sequence life shorter than 10 Ga. We also suggest that snow and glaciers are, in a statistical sense, important markers for conditions that may possibly promote the development of complex life on extrasolar planets.

  15. The size evolution of galaxy discs formed within Lambda Cold Dark Matter haloes

    CERN Document Server

    Firmani, C

    2009-01-01

    By means of galaxy evolutionary models, we explore the direct consequences of the LCDM cosmogony on the size evolution of galactic discs, avoiding intentionally the introduction of intermediate (uncertain) astrophysical processes. Based on the shape of the rotation curves and guided by a simplicity criterion, we adopt an average galaxy mass baryon fraction of 0.03. In order to study general behaviors, only models with the average initial conditions are analyzed. The stellar and B-band effective radii, R* and RB, of individual galaxies grow significantly with time (inside-out disc formation) with laws that are weakly dependent on mass, M*,or luminosity, LB. However, the change of R* with z at fixed M* is slow; for z0.75. We find also that at z=0, R* ~ M*^0.38 and RB ~ LB^0.40, remaining the slopes of these relations almost the same up to z ~ 3. Our predictions are in reasonable agreement with observational inferences on the typical radius change with z of late-type galaxies more luminous (massive) than high va...

  16. The evolution of the cold interstellar medium in galaxies following a starburst

    CERN Document Server

    Rowlands, K; Nesvadba, N; Sibthorpe, B; Mortier, A; Lehnert, M; da Cunha, E

    2014-01-01

    We present the evolution of dust and molecular gas properties in a sample of 11 $z\\sim0.03$ starburst to post-starburst (PSB) galaxies selected to span an age sequence from ongoing starburst to 1 Gyr after the starburst ended. All PSBs harbour significant molecular gas and dust reservoirs and residual star formation, indicating that complete quenching of the starburst due to exhaustion or expulsion of gas has not occurred during this timespan. As the starburst ages, we observe a clear decrease in the star-formation efficiency, molecular gas and SFR surface density, and effective dust temperature, from levels coincident with starburst galaxies to those of normal star-forming galaxies. These trends are consistent with a natural decrease in the SFR following consumption of molecular gas by the starburst, and corresponding decrease in the interstellar radiation field strength as the starburst ages. The gas and dust contents of the PSBs are coincident with those of star-forming galaxies and molecular gas-rich earl...

  17. Formation and Evolution of Planetary Systems: Cold Outer Disks Associated with Sun-like stars

    CERN Document Server

    Kim, J S; Backman, D E; Hillenbrand, L A; Meyer, M R; Rodmann, J; Moro-Martin, A; Carpenter, J M; Silverstone, M D; Bouwman, J; Mamajek, E E; Wolf, S; Malhotra, R; Pascucci, I; Najita, J; Padgett, D L; Henning, T; Brooke, T Y; Cohen, M; Strom, S E; Stobie, E B; Engelbracht, C W; Gordon, K D; Misselt, K; Morrison, J E; Muzerolle, J; Su, K Y L; Kim, Jinyoung Serena; Hines, Dean C.; Backman, Dana E.; Hillenbrand, Lynne A.; Meyer, Michael R.; Rodmann, Jens; Moro-Martin, Amaya; Carpenter, John M.; Silverstone, Murray D.; Bouwman, Jeroen; Mamajek, Eric E.; Wolf, Sebastian; Malhotra, Renu; Pascucci, Ilaria; Najita, Joan; Padgett, Deborah L.; Henning, Thomas; Brooke, Timothy Y.; Cohen, Martin; Strom, Stephen E.; Stobie, Elizabeth B.; Engelbracht, Charles W.; Gordon, Karl D.; Misselt, Karl; Morrison, Jane E.; Muzerolle, James; Su, Kate Y. L.

    2005-01-01

    We present the discovery of debris systems around three solar mass stars based upon observations performed with the Spitzer Space Telescope as part of a Legacy Science Program, ``the Formation and Evolution of Planetary Systems'' (FEPS). We also confirm the presence of debris around two other stars. All the stars exhibit infrared emission in excess of the expected photospheres in the 70 micron band, but are consistent with photospheric emission at <= 33 micron. This restricts the maximum temperature of debris in equilibrium with the stellar radiation to T < 70 K. We find that these sources are relatively old in the FEPS sample, in the age range 0.7 - 3 Gyr. Based on models of the spectral energy distributions, we suggest that these debris systems represent materials generated by collisions of planetesimal belts. We speculate on the nature of these systems through comparisons to our own Kuiper Belt, and on the likely planet(s) responsible for stirring the system and ultimately releasing dust through coll...

  18. Mechanical Properties and Microstructure Evolution of Cold-deformed High-nitrogen Nickel-free Austenitic Stainless Steel during Annealing

    Institute of Scientific and Technical Information of China (English)

    XU Mingzhou; WANG Jianjun; LIU Chunming

    2012-01-01

    The mechanical properties and microstructure evolution of cold-deformed CrMnN austenitic stainless steel annealed in a temperature ranging from 50 ℃ to 650 ℃ for 90 min and at 550 ℃ for different time were investigated by tensile test,micro hardness test,and Transmission Electron Microscope (TEM).The steel was strengthened when it got annealed at temperatures ranging from 100 ℃ to 550 ℃,while it was softened when it got annealed at temperatures ranging from 550 ℃ to 650 ℃.Annealing temperature had stronger effect on mechanical properties than annealing time.TEM observations showed that nano-sized precipitates formed when the steel was annealed at 150 ℃ for 90 min,but the size and density of precipitates had no noticeable change with annealing temperature and time.Recrystallization occurred when the steel was annealed at temperatures above 550 ℃ for 90 min,and its scale increased with annealing temperature.Nanosized annealing twins were observed.The mechanisms that controlled the mechanical behaviors of the steel were discussed.

  19. Precursor Evolution and Stress Corrosion Cracking Initiation of Cold-Worked Alloy 690 in Simulated Pressurized Water Reactor Primary Water

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Ziqing [Pacific Northwest National Laboratory, 622 Horn Rapids Road, P.O. Box 999, Richland, Washington 99352.; Toloczko, Mychailo [Pacific Northwest National Laboratory, 622 Horn Rapids Road, P.O. Box 999, Richland, Washington 99352.; Kruska, Karen [Pacific Northwest National Laboratory, 622 Horn Rapids Road, P.O. Box 999, Richland, Washington 99352.; Bruemmer, Stephen [Pacific Northwest National Laboratory, 622 Horn Rapids Road, P.O. Box 999, Richland, Washington 99352.

    2017-05-22

    Stress corrosion crack initiation of two thermally-treated, cold-worked (CW) alloy 690 (UNS N06690) materials was investigated in 360oC simulated PWR primary water using constant load tensile (CLT) tests and blunt notch compact tension (BNCT) tests equipped with direct current potential drop (DCPD) for in-situ detection of cracking. SCC initiation was not detected by DCPD for either the 21% or 31%CW CLT specimens loaded at their yield stress after ~9,220 hours, however intergranular (IG) precursor damage and isolated surface cracks were observed on the specimens. The two 31%CW BNCT specimens loaded at moderate stress intensity after several cyclic loading ramps showed DCPD-indicated crack initiation after 10,400 hours of exposure at constant stress intensity, which was resulted from significant growth of IG cracks. The 21%CW BNCT specimens only exhibited isolated small IG surface cracks and showed no apparent DCPD change throughout the test. Post-test cross-section examinations revealed many grain boundary (GB) nano-cavities in the bulk of all the CLT and BNCT specimens particularly for the 31%CW materials. Cavities were also found along GBs extending to the surface suggesting an important role in crack nucleation. This paper provides an overview of the evolution of GB cavities and discusses their effects on crack initiation in CW alloy 690.

  20. Reproductive mode evolution in lizards revisited: updated analyses examining geographic, climatic and phylogenetic effects support the cold-climate hypothesis.

    Science.gov (United States)

    Watson, C M; Makowsky, R; Bagley, J C

    2014-12-01

    Viviparity, the bearing of live young, has evolved well over 100 times among squamate reptiles. This reproductive strategy is hypothesized to allow maternal control of the foetus' thermal environment and thereby to increase the fitness of the parents and offspring. Two hypotheses have been posited to explain this phenomenon: (i) the cold-climate hypothesis (CCH), which advocates low temperatures as the primary selective force; and (ii) the maternal manipulation hypothesis (MMH), which advocates temperature variability as the primary selective force. Here, we investigate whether climatic and geographic variables associated with the CCH vs. the MMH best explain the current geographical distributions of viviparity in lizards while incorporating recent advances in comparative methods, squamate phylogenetics and geospatial analysis. To do this, we compared nonphylogenetic and phylogenetic models predicting viviparity based on point-of-capture data from 20,994 museum specimens representing 215 lizard species in conjunction with spatially explicit bioclimatic and geographic (elevation and latitude) data layers. The database we analysed emphasized Nearctic lizards from three species-rich genera (Phrynosoma, Plestiodon and Sceloporus); however, we additionally analysed a less substantial, but worldwide sample of species to verify the universality of our Nearctic results. We found that maximum temperature of the warmest month (and, less commonly, elevation and maximum temperature of the driest quarter) was frequently the best predictor of viviparity and showed an association consistent with the CCH. Our results strongly favour the CCH over the MMH in explaining lizard reproductive mode evolution.

  1. Influence of Carbon Content and Rolling Temperature on Rolling Texture in 3 Pct Si Steel

    Science.gov (United States)

    Shingaki, Y.; Takashima, M.; Hayakawa, Y.

    2016-10-01

    Effects of carbon and rolling temperature up to 453 K (180 °C) on rolling texture of 3 pct Si steel at a reduction of 66 pct were investigated using a single crystal with an initial orientation of {110}. With residual-level carbon, uniform slip deformation was observed in the specimen cold rolled at room temperature and most of initial orientation {110} rotated to {111} during the rolling. With carbon addition, the formation of the deformation twins and the shear bands were promoted in the specimen cold rolled at room temperature. Regions with {110} were observed inside the shear bands. Warm-rolled specimen with residual-level carbon had microbands containing tiny {110} regions. Warm-rolled specimen with carbon addition had both the shear bands and the microbands but no deformation twin. Additionally, there were unique band structures with rotated crystal orientation around the rolling direction from initial orientation {110}. These experimental results suggest that the carbon addition inhibits dislocation migration by the increase of the critical resolved shear stress (CRSS) and that the high deformation temperature activates multiple slip systems by the reduction of CRSS and further that the carbon addition and high deformation temperature superimposed bring about the activation of symmetrical {110} slip systems additionally.

  2. Influence of Carbon Content and Rolling Temperature on Rolling Texture in 3 Pct Si Steel

    Science.gov (United States)

    Shingaki, Y.; Takashima, M.; Hayakawa, Y.

    2017-01-01

    Effects of carbon and rolling temperature up to 453 K (180 °C) on rolling texture of 3 pct Si steel at a reduction of 66 pct were investigated using a single crystal with an initial orientation of {110}. With residual-level carbon, uniform slip deformation was observed in the specimen cold rolled at room temperature and most of initial orientation {110} rotated to {111} during the rolling. With carbon addition, the formation of the deformation twins and the shear bands were promoted in the specimen cold rolled at room temperature. Regions with {110} were observed inside the shear bands. Warm-rolled specimen with residual-level carbon had microbands containing tiny {110} regions. Warm-rolled specimen with carbon addition had both the shear bands and the microbands but no deformation twin. Additionally, there were unique band structures with rotated crystal orientation around the rolling direction from initial orientation {110}. These experimental results suggest that the carbon addition inhibits dislocation migration by the increase of the critical resolved shear stress (CRSS) and that the high deformation temperature activates multiple slip systems by the reduction of CRSS and further that the carbon addition and high deformation temperature superimposed bring about the activation of symmetrical {110} slip systems additionally.

  3. 碳含量对冷轧中锰钢双相区退火组织和力学性能的影响%Effect of Carbon Content on Microstructure and Mechanical Properties of Cold-rolled Medium Manganese Steel

    Institute of Scientific and Technical Information of China (English)

    李楠; 时捷; 陈为亮; 曹文全

    2012-01-01

    The effects of carbon content of 0.1%~0.4% on the microstructure and mechanical properties of cold-rolled medium manganese steel after annealing at 650 ℃ were investigated. The microstructure evolution during annealing process was characterized by scanning electron microscopy, the residual austenite content in the steel was determined by X-ray diffraction analysis, the mechanical properties of the annealed steel were measured by tensile tests. The results show that the austenite reverted transformation takes place, which results in a certain amount of austenite phase in the ultrafine grained annealed matrix. When carbon content increases from 0.1% to 0.2%, the tensile strength (Rm) changes little (about 1000 Mpa), the failure elongation (A) and the product of tensile strength and failure elongation (Rm × A) increases from 27% to 43% and from 28 Gpa% to 45 Gpa%, respectively. The carbon content of 0.4% significantly improves the strength of the steel (about 1200 Mpa), but the plasticity decreases. Analysis minks that the carbon of cold-rolled medium manganese steel is conducive to the formation of reverted austenite and its stability. However, high carbon content can help form a large number of carbides, which is not conducive to the formation of austenite, reducing the plasticity. The Rm A and Rm × A are attributed to the enhanced TRIP effects of the large fractioned metastable austenite and the superfine grain size.%研究了含碳量为0.1%~0.4%的冷轧态中锰钢经650℃退火后微观组织和单轴拉伸性能的变化规律.利用SEM进行了组织形貌表征,采用XRD法测量了残余奥氏体量,通过拉伸试验机测试了钢的单轴拉伸性能.结果表明,冷轧态实验钢在退火过程中都发生奥氏体逆相变,获得具有一定量亚稳奥氏体的超细晶组织;随实验钢碳含量从0.1%增加到0.2%时,钢的抗拉强度(R(m)变化不大(约1000 MPa),而断后伸长率(A)从27%升高到43

  4. Hypothesis of homeothermy evolution on isolated South China Craton that moved from equator to cold north latitudes 250-200Myr ago.

    Science.gov (United States)

    Kurbel, Sven

    2014-01-07

    Based on avian and mammalian fossils found in the northeastern Chinese province of Liaoning and physiological traits linked to homeothermy, a hypothesis of evolution of homeothermic animals is proposed. It is based on the importance of muscle function in cold environment, as a strong selection pressure that favors endothermic metabolism during periods of cold climates. The presented hypothesis postulates that in progressively cooling environment, animals will develop thermal insulation, increased basal metabolism if food is available, and torpor when food is scarce. Since late Permian, Triassic and Cretaceous global temperatures were high, an exceptional place that gradually became cold was needed for the homeothermy evolution. South China Craton is here proposed as a plausible candidate for that role since it drifted across the Paleo-Tethys ocean, from equator to high northern latitudes in a journey that lasted from 250 to 200Myr ago. After this small continent collided with North China Craton some 200Myr ago, the already cold-adapted animals had spread to large, mostly empty spaces on the North China Craton, due to their evolutionary advantage of making active living in the cold environment. The most advantageous early homeothermic animals went further north to the cold Liaoning to start an oasis that delivered modern birds during next 50Myr. Modern mammals possibly evolved somewhere in the cold vicinity. This made Liaoning and similarly cold places the cradles of early birds and early mammals since for the following millions of years these places remained too cold for poikilotherms to enter and warm enough for homeotherms to dwell, until the Cretaceous-Paleogene extinction event and subsequent global cooling that diminished poikilotherms. Homeothermy was probably even more important as a survival advantage in cooler climates of Paleogene, when mammals and birds became dominant animals. This interpretation is probably supported by a recent report that a small

  5. Explanation of Darwin's theory of evolution:cold for traditional Chinese Medicine%用达尔文进化论阐释中医:感冒

    Institute of Scientific and Technical Information of China (English)

    吴敬龙

    2013-01-01

    感冒是机体感染感冒病毒所致呼吸系统疾病,传统中医治疗感冒多疗效不佳,原因是传统的中医理论也不完全正确。本文用达尔文进化论阐释中医治疗方法,根据植物的生长特性来理解治疗感冒的原理,正确理解感冒症状形成机理,从而较好地治疗感冒。%The cold is caused by influenza virus infection of respiratory diseases, traditional Chinese medicine treatment of cold poor efficacy, the reason is the theory of traditional Chinese medicine is not entirely correct. In this paper, using Darwin's theory of evolution to explain traditional Chinese medicine treatment, to understand the principle of cold treatment according to the growth characteristics of the plants, the correct understanding of the formation mechanism of cold symptoms, so as to better treatment of colds.

  6. Cross Shear Roll Bonding

    DEFF Research Database (Denmark)

    Bay, Niels; Bjerregaard, Henrik; Petersen, Søren. B;

    1994-01-01

    The present paper describes an investigation of roll bonding an AlZn alloy to mild steel. Application of cross shear roll bonding, where the two equal sized rolls run with different peripheral speed, is shown to give better bond strength than conventional roll bonding. Improvements of up to 20......-23% in bond strength are found and full bond strength is obtained at a reduction of 50% whereas 65% is required in case of conventional roll bonding. Pseudo cross shear roll bonding, where the cross shear effect is obtained by running two equal sized rolls with different speed, gives the same results....

  7. 超声清洗法回收冷轧厂磁过滤物中的纳米铁粉%Recovering Nano-sized Iron Powders from Magnetic Filter Products of Cold Rolling Plant Using Ultrasonic Wave Cleaning Method

    Institute of Scientific and Technical Information of China (English)

    赵平; 赵立宁; 张月萍

    2012-01-01

    A method of recovering nano-sized iron powders from the magnetic filter products of cold rolling plant was developed. Pure nano-sized iron powders were obtained after the amusable oil on the surface was removed utilizing ultrasonic wave cleaning method. The influence of the ultrasonic frequency, power and temperature on the oil-removing effect was researched. The samples of iron powders were characterized by XRD and SEM. The results show that corresponding to mechanical stirring cleaning method, the oil removal capability of the cleaning liquid can be improved by using ultrasonic wave cleaning method. The mass fraction of iron in the nano-sized iron powders can reach 95.75% under the conditions that washing the iron powder 4 times of 20 minutes every time with cleaning liquid at 40 ?, ultrasonic frequency is 40 kHz, powder density is 0.44 W/cm2, rinsing with deionized water until clarifying and vacuum drying 5 h.%研究一种冷轧厂磁过滤物中纳米铁粉的回收方法,采用超声清洗法除去铁粉表面的油污,得到纯净的纳米铁粉,通过试验研究超声频率、功率密度、清洗温度对除油效果的影响,采用X射线衍射和扫描电子显微镜对铁粉产品进行表征.结果表明,相对于机械搅拌清洗,采用超声清洗含油铁粉,可提高清洗液的除油能力;超声频率为40 kHz,功率密度为0.44 W/cm2,清洗温度为40℃时,用清洗液清洗4次,每次清洗时间为20 min,用去离子水漂洗至澄清,真空干燥5h,所得纳米铁粉中铁元素的质量分数为95.75%.

  8. New Numerical Solution of von Karman Equation of Lengthwise Rolling

    Directory of Open Access Journals (Sweden)

    Rudolf Pernis

    2015-01-01

    Full Text Available The calculation of average material contact pressure to rolls base on mathematical theory of rolling process given by Karman equation was solved by many authors. The solutions reported by authors are used simplifications for solution of Karman equation. The simplifications are based on two cases for approximation of the circular arch: (a by polygonal curve and (b by parabola. The contribution of the present paper for solution of two-dimensional differential equation of rolling is based on description of the circular arch by equation of a circle. The new term relative stress as nondimensional variable was defined. The result from derived mathematical models can be calculated following variables: normal contact stress distribution, front and back tensions, angle of neutral point, coefficient of the arm of rolling force, rolling force, and rolling torque during rolling process. Laboratory cold rolled experiment of CuZn30 brass material was performed. Work hardening during brass processing was calculated. Comparison of theoretical values of normal contact stress with values of normal contact stress obtained from cold rolling experiment was performed. The calculations were not concluded with roll flattening.

  9. Influence of Hot Rolling on Cube Texture of Ni Substrate for Coated Conductor

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Pure Ni and Ni alloy tapes with sharp cube texture and low-angle grain boundaries prepared by thennomechanical process were extensively used as substrates for coated conductor. The thermomechanical process usually includes hot forging and cold rolling. In this study, a hot-rolling process between hot forging and cold rolling was induced. The influence of hot rolling on the cube texture of pure Ni was discussed. Sharp cube texture on pure Ni was obtained by suitable hot rolling, cold rolling, and recrystallization treatment. This deformation texture of tape was studied using orientation distribution function (ODF). Orientation mapping, content of the cube texture, and grain boundary distribution were performed using an EBSD system mounted on LEO-1450 SEM. The results show that the substrates that are hot rolled have a sharp cube texture and low-angle grain boundaries.

  10. A TREND BETWEEN COLD DEBRIS DISK TEMPERATURE AND STELLAR TYPE: IMPLICATIONS FOR THE FORMATION AND EVOLUTION OF WIDE-ORBIT PLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Ballering, Nicholas P.; Rieke, George H.; Su, Kate Y. L. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Montiel, Edward, E-mail: ballerin@email.arizona.edu [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803, USA. (United States)

    2013-09-20

    Cold debris disks trace the limits of planet formation or migration in the outer regions of planetary systems, and thus have the potential to answer many of the outstanding questions in wide-orbit planet formation and evolution. We characterized the infrared excess spectral energy distributions of 174 cold debris disks around 546 main-sequence stars observed by both the Spitzer Infrared Spectrograph and the Multiband Imaging Photometer for Spitzer. We found a trend between the temperature of the inner edges of cold debris disks and the stellar type of the stars they orbit. This argues against the importance of strictly temperature-dependent processes (e.g., non-water ice lines) in setting the dimensions of cold debris disks. Also, we found no evidence that delayed stirring causes the trend. The trend may result from outward planet migration that traces the extent of the primordial protoplanetary disk, or it may result from planet formation that halts at an orbital radius limited by the efficiency of core accretion.

  11. Modeling microstructural evolution of multiple texture components during recrystallization

    DEFF Research Database (Denmark)

    Vandermeer, R.A.; Juul Jensen, D.

    1994-01-01

    using stereological point and lineal measurements of microstructural properties in combination with EBSP analysis for orientation determinations. The potential of the models to describe the observed recrystallization behavior of heavily cold-rolled commercial aluminum was demonstrated. A successful MPM......Models were formulated in an effort to characterize recrystallization in materials with multiple texture components. The models are based on a microstructural path methodology (MPM). Experimentally the microstructural evolution of conmmercial aluminum during recrystallization was characterized...

  12. Numerical Modeling of Tube Forming by HPTR Cold Pilgering Process

    Science.gov (United States)

    Sornin, D.; Pachón-Rodríguez, E. A.; Vanegas-Márquez, E.; Mocellin, K.; Logé, R.

    2016-09-01

    For new fast-neutron sodium-cooled Generation IV nuclear reactors, the candidate cladding materials for the very strong burn-up are ferritic and martensitic oxide dispersion strengthened grades. Classically, the cladding tube is cold formed by a sequence of cold pilger milling passes with intermediate heat treatments. This process acts upon the geometry and the microstructure of the tubes. Consequently, crystallographic texture, grain sizes and morphologies, and tube integrity are highly dependent on the pilgering parameters. In order to optimize the resulting mechanical properties of cold-rolled cladding tubes, it is essential to have a thorough understanding of the pilgering process. Finite Element Method (FEM) models are used for the numerical predictions of this task; however, the accuracy of the numerical predictions depends not only on the type of constitutive laws but also on the quality of the material parameters identification. Therefore, a Chaboche-type law which parameters have been identified on experimental observation of the mechanical behavior of the material is used here. As a complete three-dimensional FEM mechanical analysis of the high-precision tube rolling (HPTR) cold pilgering of tubes could be very expensive, only the evolution of geometry and deformation is addressed in this work. The computed geometry is compared to the experimental one. It is shown that the evolution of the geometry and deformation is not homogeneous over the circumference. Moreover, it is exposed that the strain is nonhomogeneous in the radial, tangential, and axial directions. Finally, it is seen that the dominant deformation mode of a material point evolves during HPTR cold pilgering forming.

  13. Microstructure Evolution and Mechanical Properties of C-Mn Cold Rolled Dual Phase Steel after Continuous Annealing Process in Laboratory Conditions

    Directory of Open Access Journals (Sweden)

    Šebek M.

    2014-06-01

    Full Text Available Praca dotyczy wpływu parametrów wyżarzania na zmiany mikrostruktury i właściwości mechaniczne stali dwufazowej C-Mn. Stal dwufazową poddano wyżarzaniu w warunkach laboratoryjnych według trzech wybranych cykli: w zakresie między krytycznym (780°C. w obszarze austenitu (920°C i w obszarze austenitu (920°C ze schładzaniem do zakresu między- krytycznego (780*0 przy temperaturze wytrzymania 495°C. Przeprowadzono symulację schematów wyżarzania przy użyciu symulatora obróbki cieplno-plastycznej Gleeble. Uzyskana mikrostruktura składa się z trzech faz: osnowy terrytycznej. martenzytu oraz ziaren martenzytu/bainitu. W celu identyfikacji mikrostruktury wykonano badania metodą TEM oraz nanoindentacji.

  14. Evolution of stability in a cold-active enzyme elicits specificity relaxation and highlights substrate-related effects on temperature adaptation.

    Science.gov (United States)

    Gatti-Lafranconi, Pietro; Natalello, Antonino; Rehm, Sascha; Doglia, Silvia Maria; Pleiss, Jürgen; Lotti, Marina

    2010-01-08

    Molecular aspects of thermal adaptation of proteins were studied by following the co-evolution of temperature dependence, conformational stability, and substrate specificity in a cold-active lipase modified via directed evolution. We found that the evolution of kinetic stability was accompanied by a relaxation in substrate specificity. Moreover, temperature dependence and selectivity turned out to be mutually dependent. While the wild-type protein was strictly specific for short-chain triglycerides (C4) in the temperature range 10-50 degrees C and displayed highest activity in the cold, its stabilized variant was able to accept C8 and C12 molecules and its selectivity was temperature dependent. We could not detect any improvement in the overall structural robustness of the mutant when the structure was challenged by temperature or chemical denaturants. There is, however, strong evidence for local stabilization effects in the active-site region provided by two independent approaches. Differential scanning fluorimetry revealed that the exposure of hydrophobic patches (as the active site is) precedes denaturation, and molecular dynamics simulations confirmed that stability was obtained by restriction of the mobility of the lid, a flexible structure that regulates the access to the enzyme active site and influences its stability. This reduction of lid movements is suggested to be accompanied by a concomitant increase in the mobility of other protein regions, thus accounting for the observed broadening of substrate specificity.

  15. Analysis of CVC roll contour and determination of roll crown

    Institute of Scientific and Technical Information of China (English)

    Guang Xu; Xianjun Liu; Jiarong Zhao; Junwei Xiong

    2007-01-01

    Mathematical analysis of continuous variable crown (CVC) roll contour used in CSP production line was conducted and the roll contour function of CVC roll was obtained. The validation with actual CVC roll contour shows that the calculation values of the roll contour function and the actual roll contour parameters given by equipment provider are the same, which proves that the roll contour function of CVC rolls given in this article is correct. The nonlinear relationship between the roll crown of CVC rolls and roll shift amounts was deduced. The concept of crown extremum was given.

  16. 冷轧钢表面复合纳米硅烷膜的耐蚀性能研究%Study on Corrosion Resistance of Composite Nano Silane Films on the Surface of Cold Rolled Steel

    Institute of Scientific and Technical Information of China (English)

    高凯歌; 郭冰; 王永辉; 王源云阳; 陈廷伟; 鲁道荣

    2013-01-01

    采用正交试验法探讨了在冷轧钢表面制备复合纳米硅烷膜的最佳工艺条件,通过塔菲尔曲线研究了硅烷膜在3.50%NaCl溶液中的自腐蚀电流密度与自腐蚀电位.实验表明,形成复合纳米硅烷膜的最佳工艺条件为:水解温度为40℃、水解时间为8h、水解溶液的pH为10、水解溶液各组分的体积比为V(γ-APS硅烷)∶V(乙醇)∶V(水)=7∶22∶75、浸涂时间20 min、固化温度90℃、固化时间20 min.纳米材料最佳用量为0.3g·L-1.通过阳极极化曲线研究了存在与不存在纳米材料的硅烷膜的耐蚀性能,用扫描电子显微镜观察了在相同超电势下存在与不存在硅烷膜的冷轧钢在腐蚀前后的形貌变化.结果表明,复合纳米硅烷膜的耐蚀性能明显优于纯γ-APS硅烷膜.%It was studied on the best craftwork condition of composite nano silane films on the surface of cold rolled steel by orthogonal experiment,and the corrosion current density and corrosion potential of the composite nano silane films was studied in 3.5% NaCl solution by Tafel curves.The experiment indicate,the optimum process conditions of prepared composite nano silane films as follows:hydrolysis temperature was 40 ℃,hydrolysis time was 8 h,the pH value of the solution was 10,100 mL solution containing 7 mL γ-APS and the composition of the solvent ethanol and water ratio was 22:75,curing temperature of films was 90 ℃,coating time was 20 min,curing time was 20 min.The best dosage of ZSM-5 nanometer materials was 100 mL solution containing 30 mg ZSM-5 nanometer materials.The corrosion resistance of the composite nano silane films and nano silane without nanometer materials was studied by using anode polarization curve testing.The change in the shape of the composite nano silane films and nano silane without nanometer materials before and after corrosion testing under same overpotential was researched by scanning electron microscope.The study indicated that the

  17. SENSITIVITY ANALYSIS FOR ROLLING PROCESS BASED ON SUPPORT VECTOR MACHINE

    Institute of Scientific and Technical Information of China (English)

    Huang Yanwei; Wu Tihua; Zhao Jingyi; Wang Yiqun

    2005-01-01

    A method for the calculation of the sensitivity factors of the rolling process has been obtained by differentiating the roll force model based on support vector machine. It can eliminate the algebraic loop of the analytical model of the rolling process. The simulations in the first stand of five stand cold tandem rolling mill indicate that the calculation for sensitivities by this proposed method can obtain a good accuracy, and an appropriate adjustment on the control variables determined directly by the sensitivity has an excellent compensation accuracy. Moreover, the roll gap has larger effect on the exit thickness than both front tension and back tension, and it is more efficient to select the roll gap as the controlvariable of the thickness control system in the first stand.

  18. Rolling induced size effects in elastic–viscoplastic sheet metals

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2015-01-01

    Rolling processes for which the characteristic length scale reaches into the range where size effects become important are receiving increased interest. In particularly, this is owed to the roll-molding process under development for high-throughput of micron-scale surface features. The study...... presented revolves around the rolling induced effect of visco-plasticity (ranging hot and cold rolling) in combination with strain gradient hardening – including both dissipative and energetic contributions. To bring out first order effects on rolling at small scale, the modeling efforts are limited to flat...... sheet rolling, where a non-homogeneous material deformation takes place between the rollers. Large strain gradients develop where the rollers first come in contact with the sheet, and a higher order plasticity model is employed to illustrate their influence at small scales. The study reveals...

  19. Computation of Rolling Stand Parameters by Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    František Ďurovský

    2008-05-01

    Full Text Available Mathematical model of rolling process is used at cold mill rolling on tandemmills in metallurgy. The model goal is to analyse rolling process according to process datameasured on the mill and get immeasurable variables necessary for rolling control andoptimal mill pre-set for next rolled coil. The values obtained by model are used asreferences for superimposed technology controllers (thickness, speed, tension, etc. as well.Considering wide steel strip assortment (different initial and final thickness, differenthardness, and fluctuation of tandem mill parameters (change of friction coefficient, workrolls abrasion, temperature fluctuation, etc. the exact analysis of tandem is complicated.The paper deals with an identification of friction coefficient on a single rolling mill standby a genetic algorithm. Mathematical description of tandem mill stand is based on themodified Bland-Ford model. Results are presented in graphical form.

  20. Surface asperity evolution and microstructure analysis of Al 6061T5 alloy in a quasi-static cold uniaxial planar compression (CUPC)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hejie, E-mail: hejiel2003@gmail.com [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Jiang, Zhengyi, E-mail: jiang@uow.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Wei, Dongbin [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); School of Electrical, Mechanical and Mechatronic Systems, University of Technology, Sydney, NSW 2007 (Australia); Gao, Xingjian [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Xu, Jianzhong; Zhang, Xiaoming [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang, Liaoning 110004 (China)

    2015-08-30

    Highlights: • We used AFM and EBSD to analyses the surface asperity flattening process. • Analysis of the influence of deformation rate on the surface asperity flattening. • Investigation of the effect of lubrication on microstructure development. • Deformation rate influence the generation of orientation components obviously. - Abstract: In a quasi-static cold uniaxial planar compression, surface asperity evolution and microstructure analysis of Al 6061T5 alloy are carried out by employing Atomic Force Microscope (AFM) and Electron Backscattered Diffraction (EBSD) methods. Strain rate affects the surface asperity evolution obviously. While lubrication can hinder the surface asperity flattening by constraining the surface localized deformation. Lubrication can accelerate the crystallization in CUPC process. It also impedes the activation of some orientation components by hindering the activation of related slip systems in light metal Al alloy.

  1. Cold Stress

    Science.gov (United States)

    ... Publications and Products Programs Contact NIOSH NIOSH COLD STRESS Recommend on Facebook Tweet Share Compartir Workers who ... cold environments may be at risk of cold stress. Extreme cold weather is a dangerous situation that ...

  2. Design of Rolling State Observers for Application to Control of Thickness and Tension in Rolling Mills

    Directory of Open Access Journals (Sweden)

    Hamid R. Koofigar

    2011-09-01

    Full Text Available This study focuses on the necessity of designing state observers to be used in controller synthesis for rolling processes. This is motivated by the fact that using several kinds of sensors for measuring all of process variables is technically and economically avoided. On the other hand, using exact measurement in feedback control systems could considerably improve the quality of products. In other word, there is a trade-off between high quality and the implementation limitations, managed here by developing rolling state observers. The proposed observers estimate the states not measured directly by the installed sensors. This technique is applicable to both hot rolling and cold rolling processes. Simulation results demonstrate the performance of the proposed estimation algorithm.

  3. Effect of Controlled Cooling After Hot Rolling on Mechanical Properties of Hot Rolled TRIP Steel

    Institute of Scientific and Technical Information of China (English)

    WU Di; LI Zhuang; L(U) Hui-sheng

    2008-01-01

    A three-step cooling pattern on the runout table (ROT) was conducted for the hot rolled TRIP steel. Microstructural evolution during thermomechanical controlled processing (TMCP) was investigated. Proeessing condition of controlled cooling on a ROT in the laboratory rolling mill was discussed. The results indicated that the microstructure containing polygonal ferrite, granular bainite and a significant amount of the stable retained austenite can be obtained through three-step cooling on the ROT after hot rolling. TMCP led to ferrite grain refinement. Controlled cooling after hot rolling resulted in the stability of the remaining austenite and a satisfactory TRIP effect. Excellent mechanical properties were obtained through TMCP for the hot rolled TRIP steel.

  4. 冷轧机附加倾斜后双侧非对称轧制力的计算%Asymmetric Roll Force Calculation With Additional Tilt for Drive Side and Operator Side of Cold Strip Mill

    Institute of Scientific and Technical Information of China (English)

    刘宝权; 张鸿; 王自东; 王军生; 张岩

    2011-01-01

    对冷轧带钢轧制过程中因辊缝倾斜调整过量所导致的单边浪缺陷和断带进行了分析,应用影响函数法计算辊系变形,通过迭代计算出附加倾斜后的传动侧轧制力、操作侧轧制力、辊间压力分布、单位宽度轧制力分布、出口厚度横向分布、出口横向张应力分布。理论计算和实际测量结果表明,冷轧机双侧轧制力差值与倾斜调整量呈近似线性增长的规律。根据轧制力差值与倾斜量之间的比例关系,用实测轧制力差值对倾斜值进行动态限幅,可有效避免冷轧过程中断带事故的发生。%The single edge wave and strip break caused by excessive tilting adjustment were analyzed. Influence func tion method was adopted to model the roll deformation. Adding different tilt, roll force of drive side, roll force of operator side, transverse distribution of contact pressure between rolls, transverse distribution of roll force, trans verse distribution of strip thickness at exit side and transverse distribution of tension at exit side were calculated by using iterative method. The theoretical calculation and the actual measurement results show that the difference be- tween the bilateral increases almost linearly with tilt adjustment value. The break strip accidents are effectively aver ted by dynamic limiting to tilt setting value with the measured differential roll force, according to the proportional relationship between the differential roll force and the tilt.

  5. Effect of precipitation on the evolution of cube recrystallization texture

    Energy Technology Data Exchange (ETDEWEB)

    Benum, S. [Hydro Aluminium, Haavik (Norway). R and D Materials Technology; Nes, E. [Norwegian Univ. of Science and Technology, Trondheim (Norway). Dept. of Metallurgy

    1997-11-01

    A study of the evolution of recrystallized structure and texture in the surface of a cold rolled twin roll cast AlFeSi alloy is presented. Annealing of such alloys often results in an abnormally coarse grained recrystallized surface structure with a strong cube texture. The evolution of this structure depends on the annealing procedures, that is, the precipitation state. Increased amounts of precipitating particles increase the grain size and the fraction of cube texture. The oriented growth theory does not offer any plausible interpretation of this precipitation effect. A recrystallization model that incorporates the differences in Zener drag between different annealing procedures has shown that the evolution of a strong cube texture and coarse grains is the result of a preferential nucleation of cube oriented grains. Precipitation increases the critical nucleation diameter and the resulting grain size. Cube oriented subgrains have a size advantage compared to other potential nucleation sites and are therefore not so affected by precipitation.

  6. Inflation with a constant rate of roll

    Science.gov (United States)

    Motohashi, Hayato; Starobinsky, Alexei A.; Yokoyama, Jun'ichi

    2015-09-01

    We consider an inflationary scenario where the rate of inflaton roll defined by ̈phi/H dot phi remains constant. The rate of roll is small for slow-roll inflation, while a generic rate of roll leads to the interesting case of 'constant-roll' inflation. We find a general exact solution for the inflaton potential required for such inflaton behaviour. In this model, due to non-slow evolution of background, the would-be decaying mode of linear scalar (curvature) perturbations may not be neglected. It can even grow for some values of the model parameter, while the other mode always remains constant. However, this always occurs for unstable solutions which are not attractors for the given potential. The most interesting particular cases of constant-roll inflation remaining viable with the most recent observational data are quadratic hilltop inflation (with cutoff) and natural inflation (with an additional negative cosmological constant). In these cases even-order slow-roll parameters approach non-negligible constants while the odd ones are asymptotically vanishing in the quasi-de Sitter regime.

  7. Improvement of tensile properties of pure Cu and CuCrZr alloy by cryo-rolling process

    Energy Technology Data Exchange (ETDEWEB)

    Ihira, Ryota; Gwon, Hyoseong; Kasada, Ryuta, E-mail: r-kasada@iae.kyoto-u.ac.jp; Konishi, Satoshi

    2016-11-01

    Highlights: • We investigated the effect of cryo-rolling process to Cu and CuCrZr alloy by tensile test and EBSD. • Cryo-rolling process simaltaneously increased strength and ductility of Cu as previously reported. • Cryo-rolling process increased strength of CuCrZr alloy without loss-of-ductility compared with conventional cold-rolling process. • We observed heterogeneous grain size distribution in cryo-rolled Cu but not in cryo-rolled CuCrZr alloy. • We found temperature-transition of texture formation in the rolled CuCrZr alloy. - Abstract: The present study investigates the effect of cryo-rolling process, i.e. cold-rolling at liquid-nitrogen temperature followed by heat treatment, on tensile properties of pure copper and precipitation-hardened CuCrZr alloy. The cryo-rolling process resulted in a simultaneous improvement of strength and ductility of pure copper. On the other hand, a cryo-rolled CuCrZr alloy showed higher tensile strength but comparable ductility with a conventional cold-rolled CuCrZr alloy. Microstructural analysis indicates that the drastically-beneficial effect of cryo-rolling on pure copper may be due to its heterogeneous size distribution of grains which consist of cryo-rolled fine grains, residual cryo-rolled grains and recrystallized coarse grains. The modest but certain benefit of cryo-rolling on CuCrZr alloy can be explained by different texture formation compared with conventional cold-rolling. Effect of neutron irradiation on tensile properties of cryo-rolled CuCrZr alloy is also examined.

  8. Rolling Force Prediction in Heavy Plate Rolling Based on Uniform Differential Neural Network

    Directory of Open Access Journals (Sweden)

    Fei Zhang

    2016-01-01

    Full Text Available Accurate prediction of the rolling force is critical to assuring the quality of the final product in steel manufacturing. Exit thickness of plate for each pass is calculated from roll gap, mill spring, and predicted roll force. Ideal pass scheduling is dependent on a precise prediction of the roll force in each pass. This paper will introduce a concept that allows obtaining the material model parameters directly from the rolling process on an industrial scale by the uniform differential neural network. On the basis of the characteristics that the uniform distribution can fully characterize the solution space and enhance the diversity of the population, uniformity research on differential evolution operator is made to get improved crossover with uniform distribution. When its original function is transferred with a transfer function, the uniform differential evolution algorithms can quickly solve complex optimization problems. Neural network structure and weights threshold are optimized by uniform differential evolution algorithm, and a uniform differential neural network is formed to improve rolling force prediction accuracy in process control system.

  9. Evolution of body size, vision, and biodiversity of coral-associated organisms: evidence from fossil crustaceans in cold-water coral and tropical coral ecosystems.

    Science.gov (United States)

    Klompmaker, Adiël A; Jakobsen, Sten L; Lauridsen, Bodil W

    2016-06-16

    Modern cold-water coral and tropical coral environments harbor a highly diverse and ecologically important macrofauna of crustaceans that face elevated extinction risks due to reef decline. The effect of environmental conditions acting on decapod crustaceans comparing these two habitats is poorly understood today and in deep time. Here, we compare the biodiversity, eye socket height as a proxy for eye size, and body size of decapods in fossil cold-water and tropical reefs that formed prior to human disturbance. We show that decapod biodiversity is higher in fossil tropical reefs from The Netherlands, Italy, and Spain compared to that of the exceptionally well-preserved Paleocene (Danian) cold-water reef/mound ecosystem from Faxe (Denmark), where decapod diversity is highest in a more heterogeneous, mixed bryozoan-coral habitat instead of in coral and bryozoan-dominated facies. The relatively low diversity at Faxe was not influenced substantially by the preceding Cretaceous/Paleogene extinction event that is not apparent in the standing diversity of decapods in our analyses, or by sampling, preservation, and/or a latitudinal diversity gradient. Instead, the lower availability of food and fewer hiding places for decapods may explain this low diversity. Furthermore, decapods from Faxe are larger than those from tropical waters for half of the comparisons, which may be caused by a lower number of predators, the delayed maturity, and the increased life span of crustaceans in deeper, colder waters. Finally, deep-water specimens of the benthic crab Caloxanthus from Faxe exhibit a larger eye socket size compared to congeneric specimens from tropical reefs, suggesting that dim light conditions favored the evolution of relatively large eyes. The results suggest a strong habitat control on the biodiversity of crustaceans in coral-associated environments and that the diversity difference between deep, cold-water reefs and tropical reefs evolved at least ~63 million years ago

  10. Evolution of Microstructure in Rolled Mg-Based Alloy. Textural Aspect / Ewolucja Mikrostruktury W Walcowanym Stopie Na Bazie Mg. Aspekt Teksturowy

    Directory of Open Access Journals (Sweden)

    Drzymała P.

    2015-12-01

    Full Text Available Magnesium alloys are the lightest structural materials, which makes them particularly suitable for use in the aircraft and automotive industry. However, due to hexagonal close-packed crystal structure, resulting in insufficient number of independent slip systems, magnesium alloys exhibit poor formability at room temperature. Conventional methods of work hardening of magnesium alloys requires the temperature about 300°C, which favours simultaneously processes of thermal recovery and grain growth, but decreases beneficial microstructure strengthening effect. Thus, it is a crucial to undertake development of a technology for semi-finished magnesium alloys elements, which will ensure better mechanical properties of the final products by forming desirable microstructure. In the paper we present the development of crystallographic texture of the Mg-based alloy (Mg-AZ31 in the form of pipe extruded at 430°C and subjected to pilger rolling at relatively low temperature.

  11. Investigation of the Microstructure of Rolled Semi-Solid Steel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper, spring steel-60Si2Mn and stainless steel-1Cr18Ni9Ti were rolled one pass in the semi-solid state. The microstructural evolution during rolling of the steels with different solid fraction was investigated. The experimental results showed that the manner of liquid and solid phases flowing and deforming was different. During rolling, most of solid phases remained in the center of the rolled specimens, while liquid phase flowed to the edge, which resulted in the macrosegregation of liquid and solid phases. Only the amount of solid fraction reached a certain value, were the solid phases deformed and flattened.

  12. Rolling Shutter Motion Deblurring

    KAUST Repository

    Su, Shuochen

    2015-06-07

    Although motion blur and rolling shutter deformations are closely coupled artifacts in images taken with CMOS image sensors, the two phenomena have so far mostly been treated separately, with deblurring algorithms being unable to handle rolling shutter wobble, and rolling shutter algorithms being incapable of dealing with motion blur. We propose an approach that delivers sharp and undis torted output given a single rolling shutter motion blurred image. The key to achieving this is a global modeling of the camera motion trajectory, which enables each scanline of the image to be deblurred with the corresponding motion segment. We show the results of the proposed framework through experiments on synthetic and real data.

  13. Cold Urticaria

    Science.gov (United States)

    Diseases and Conditions Cold urticaria By Mayo Clinic Staff Cold urticaria (ur-tih-KAR-e-uh) is a skin reaction to cold. Skin that has ... in contact with cold develops reddish, itchy welts (hives). The severity of cold urticaria symptoms varies widely. ...

  14. Rolling induced size effects in elastic–viscoplastic sheet metals

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2015-01-01

    presented revolves around the rolling induced effect of visco-plasticity (ranging hot and cold rolling) in combination with strain gradient hardening – including both dissipative and energetic contributions. To bring out first order effects on rolling at small scale, the modeling efforts are limited to flat...... sheet rolling, where a non-homogeneous material deformation takes place between the rollers. Large strain gradients develop where the rollers first come in contact with the sheet, and a higher order plasticity model is employed to illustrate their influence at small scales. The study reveals...... that the energetic length parameter has negligible effect on the rolling quantities of interest, while the contribution coming from the dissipative length parameter can be dominant. Considering a slow and a fast moving sheet, respectively, convergence towards the rate independent limit is demonstrated...

  15. Cube orientation in hot rolled high purity aluminum plate

    Institute of Scientific and Technical Information of China (English)

    杨平; 毛卫民

    2003-01-01

    X-ray diffraction and orientation mapping in EBSD measurement were applied to obtain information ofdeformation and recrystallization with the emphasis on the cube orientation in hot rolled high purity aluminumplates. It is shown that cube orientations are retained to a large extent during hot rolling. Some deformed cubegrains are found to have experienced large extent of recovery according to their Kikuchi band contrasts. The de-formed cube-oriented grains in hot rolled plates are in an unfavorite growth condition with respect to their neighbor-ing grain orientations for the subsequent annealing. The reasons for the phenomena observed, as well as the influ-ence of hot rolling process on subsequent cold rolling and final annealing were discussed.

  16. The Genome Sequence of the psychrophilic archaeon, Methanococcoides burtonii: the Role of Genome Evolution in Cold-adaptation

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Michelle A.; Lauro, Federico M.; Williams, Timothy J.; Burg, Dominic; Siddiqui, Khawar S.; De Francisci, David; Chong, Kevin W.Y.; Pilak, Oliver; Chew, Hwee H.; De Maere, Matthew Z.; Ting, Lily; Katrib, Marilyn; Ng, Charmaine; Sowers, Kevin R.; Galperin, Michael Y.; Anderson, Iain J.; Ivanova, Natalia; Dalin, Eileen; Martinez, Michelle; Lapidus, Alla; Hauser, Loren; Land, Miriam; Thomas, Torsten; Cavicchioli, Ricardo

    2009-04-01

    Psychrophilic archaea are abundant and perform critical roles throughout the Earth's expansive cold biosphere. Here we report the first complete genome sequence for a psychrophilic methanogenic archaeon, Methanococcoides burtonii. The genome sequence was manually annotated including the use of a five tiered Evidence Rating system that ranked annotations from Evidence Rating (ER) 1 (gene product experimentally characterized from the parent organism) to ER5 (hypothetical gene product) to provide a rapid means of assessing the certainty of gene function predictions. The genome is characterized by a higher level of aberrant sequence composition (51%) than any other archaeon. In comparison to hyper/thermophilic archaea which are subject to selection of synonymous codon usage, M. burtonii has evolved cold adaptation through a genomic capacity to accommodate highly skewed amino acid content, while retaining codon usage in common with its mesophilic Methanosarcina cousins. Polysaccharide biosynthesis genes comprise at least 3.3% of protein coding genes in the genome, and Cell wall/membrane/envelope biogenesis COG genes are over-represented. Likewise, signal transduction (COG category T) genes are over-represented and M. burtonii has a high 'IQ' (a measure of adaptive potential) compared to many methanogens. Numerous genes in these two over-represented COG categories appear to have been acquired from {var_epsilon}- and {delta}-proteobacteria, as do specific genes involved in central metabolism such as a novel B form of aconitase. Transposases also distinguish M. burtonii from other archaea, and their genomic characteristics indicate they play an important role in evolving the M. burtonii genome. Our study reveals a capacity for this model psychrophile to evolve through genome plasticity (including nucleotide skew, horizontal gene transfer and transposase activity) that enables adaptation to the cold, and to the biological and physical changes that have

  17. Partition Decomposition for Roll Call Data

    CERN Document Server

    Leibon, Greg; Rockmore, Daniel N; Savell, Robert

    2011-01-01

    In this paper we bring to bear some new tools from statistical learning on the analysis of roll call data. We present a new data-driven model for roll call voting that is geometric in nature. We construct the model by adapting the "Partition Decoupling Method," an unsupervised learning technique originally developed for the analysis of families of time series, to produce a multiscale geometric description of a weighted network associated to a set of roll call votes. Central to this approach is the quantitative notion of a "motivation," a cluster-based and learned basis element that serves as a building block in the representation of roll call data. Motivations enable the formulation of a quantitative description of ideology and their data-dependent nature makes possible a quantitative analysis of the evolution of ideological factors. This approach is generally applicable to roll call data and we apply it in particular to the historical roll call voting of the U.S. House and Senate. This methodology provides a...

  18. Direct investigations on strain-induced cold crystallization behavior and structure evolutions in amorphous poly(lactic acid) with SAXS and WAXS measurements

    DEFF Research Database (Denmark)

    Zhou, Chengbo; Li, Hongfei; Zhang, Wenyang

    2016-01-01

    Strain-induced cold crystallization behavior and structure evolution of amorphous poly(lactic acid) (PLA) stretched within 70-90 degrees C were investigated via in situ synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) measurements as well as differential...... first then forms crystal with strain increasing. The stacked structure consisting of less perfect crystalline phase, mesocrystal and oriented amorphous phase emerges at the final stage of stretching. Drawing at 80 degrees C, only the crystal can be induced at lower strain with higher crystallization...... in strain-induced crystallization behavior of amorphous PLA within 70-90 degrees C can be attributed to the competition between chain orientation caused by stretching and chain relaxation. It was proposed that the strain-induced mesocrystal/crystal and the lamellae are formed from the mesophase originally...

  19. Microstructural investigation on marforming and conventional cold deformation in Ni-Ti-Fe-based shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Ritwik; Szpunar, Jerzy; Eskandari, Mostafa; Mohtadi-Bonab, M.A. [Univ. Saskatchewan, Dept. of Mechanical Engineering, Saskatoon (Canada)

    2015-08-15

    A hot-rolled Ni-Ti-Fe alloy was subjected to 50% cold rolling by laboratory rolling mill and was subsequently annealed at 800 C for 1.5 h. This sample was then deformed through another 10% reduction in thickness by two different routes (i) conventional cold rolling and (ii) marforming (rolling in liquid nitrogen) followed by annealing under identical conditions. The grain refinement during normal cold rolling was attributed to relatively large presence of dislocations in the ND // left angle 110 right angle grains in the starting microstructure. The regions of higher dislocation densities became gradually textured to ND // left angle 111 right angle orientation, with cold rolling. Marforming (deformation in liquid nitrogen following phase transformation) on the other hand led to more significant grain refinement and also change in the bulk texture. The objective of this study was to compare the grain refinement and microstructural modification produced through marforming with that obtained in conventional cold deformation.

  20. Evolution of a high local strain in rolling up MoS2 sheets decorated with Ag and Au nanoparticles for surface-enhanced Raman scattering