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Sample records for forged thick section

  1. Manufacturing of aluminum alloy ultra-thick plates by multidirectional forging and subsequent rolling

    Institute of Scientific and Technical Information of China (English)

    张辉; 林高用; 彭大暑; 杨立斌; 林启权

    2002-01-01

    A combinatory large deformation model of multidirectional forging and subsequent rolling was proposed for producing high performance aluminum alloy ultra-thick plates.The results show that fine-grain (2~3 μm) structures were obtained when total deformation coefficient λ =32 at 250~350 ℃ under a strain rate of about 0.1 s-1.The development of fine-grained structure can be characterized by the formation of strain-induced high energy dislocation and then transforms into new grain under large deformation at moderate temperature.The very fine secondary particles formed during large deformation play important role in retain the stability of the fine-grained structures.

  2. A Technique for Section Thickness Evaluation for Microphotometry and Image Analysis of Sectioned Nuclei

    Directory of Open Access Journals (Sweden)

    R. L. Cabrini

    1998-01-01

    Full Text Available The exact knowledge of the section thickness is a requisite for making the necessary corrections on DNA measurements in tissue sections. Several methods have been proposed to evaluate section thickness, each of them with advantages and disadvantages depending on the type of specimen and equipment available. We herein report another method based on preparation of standard material whose optical density varies as a function of its thickness and is sectioned and measured alongside the tissue specimen. The standards consist of celloidin cylinders stained with the PAS reaction and embedded in paraffin. For prior characterization of the cylinders, sections of different thickness were obtained and mounted. The optical density of each section was measured by direct microphotometry or image analysis. The actual thickness of each section was evaluated following re-embedding of piled groups of sections in a paraffin block and transversal sectioning. The thickness was then measured with a micrometric eye-piece. Optical density and actual thickness of each section were plotted on a normogram curve. Once a given tissue is sectioned alongside with the reference cylinder, the actual thickness is determined by its optical density on the normogram curve.

  3. Economical Fabrication of Thick-Section Ceramic Matrix Composites

    Science.gov (United States)

    Babcock, Jason; Ramachandran, Gautham; Williams, Brian; Benander, Robert

    2010-01-01

    A method was developed for producing thick-section [>2 in. (approx.5 cm)], continuous fiber-reinforced ceramic matrix composites (CMCs). Ultramet-modified fiber interface coating and melt infiltration processing, developed previously for thin-section components, were used for the fabrication of CMCs that were an order of magnitude greater in thickness [up to 2.5 in. (approx.6.4 cm)]. Melt processing first involves infiltration of a fiber preform with the desired interface coating, and then with carbon to partially densify the preform. A molten refractory metal is then infiltrated and reacts with the excess carbon to form the carbide matrix without damaging the fiber reinforcement. Infiltration occurs from the inside out as the molten metal fills virtually all the available void space. Densification to 41 ksi (approx. 283 MPa) flexural strength.

  4. Automatic section thickness determination using an absolute gradient focus function.

    Science.gov (United States)

    Elozory, D T; Kramer, K A; Chaudhuri, B; Bonam, O P; Goldgof, D B; Hall, L O; Mouton, P R

    2012-12-01

    Quantitative analysis of microstructures using computerized stereology systems is an essential tool in many disciplines of bioscience research. Section thickness determination in current nonautomated approaches requires manual location of upper and lower surfaces of tissue sections. In contrast to conventional autofocus functions that locate the optimally focused optical plane using the global maximum on a focus curve, this study identified by two sharp 'knees' on the focus curve as the transition from unfocused to focused optical planes. Analysis of 14 grey-scale focus functions showed, the thresholded absolute gradient function, was best for finding detectable bends that closely correspond to the bounding optical planes at the upper and lower tissue surfaces. Modifications to this function generated four novel functions that outperformed the original. The 'modified absolute gradient count' function outperformed all others with an average error of 0.56 μm on a test set of images similar to the training set; and, an average error of 0.39 μm on a test set comprised of images captured from a different case, that is, different staining methods on a different brain region from a different subject rat. We describe a novel algorithm that allows for automatic section thickness determination based on just out-of-focus planes, a prerequisite for fully automatic computerized stereology.

  5. 大型厚壁封头热锻成形中降低成型载荷的策略%Strategy of Decreasing Forming Load in Hot Forging of Heavy Thick-wall Sealing Head

    Institute of Scientific and Technical Information of China (English)

    徐戊矫; 丁永峰; 邹明平; 王凯庆

    2011-01-01

    The forging process for the heavy thick-wall saling head is required to neet the severe condition,whereas the forging factories often face eith the insufficient forging capacity to execute the foring process. Based on the rigid-viscoplastic FEM platform DEFORM-3D, the upper anvil swaging foring process was simulatde to ana1yze the cause of the fold defer and much higher forming load. The configuration of the upper anvil was optimized in the shape of saddle,meanwhile, the reduction of per revolution was deternined as 100 mm and the rotary anglc of per reduction of the upper anvil was decided as 24°. The optimized process was numerically simulated The results show that the forming load to execute the forging process is decreased to available range and the fold is avoided in the finished forgings The research is very helpful to improve the feasibility of forging proccss and forming quality of heavy thick-wall sealing head.%大型厚壁封头严苛的使用性能要求其采用整体锻造方法生产,但锻造企业通常不具备足够的设备能力以满足封头整体锻造超高的力能需求.基于刚粘塑性有限元模拟平台DEFORM-3D,对大型厚壁封头上砧旋转锻造成形原有的工艺方案进行了模拟仿真,分析了产生折迭缺陷和锻造载荷超限的原因.优化上砧形状为马鞍型,并确定上砧的运动轨迹为单周压下量为100mm,每压下一次后上砧旋转角度为24°.对优化后的工艺方案进行仿真计算.结果表明,工艺优化有效地将所需的成形载荷降到了设备能力允许的范围之内,并使整体锻造的封头无折迭缺陷.研究结果对提高封头整体锻造的可行性及改善大型厚壁封头的成形质量具有重要的指导意义.

  6. Investigating the effect of variable gutter technique as a novel method on vertical flow of material in closed die forging processes

    Energy Technology Data Exchange (ETDEWEB)

    Pourbashiri, M.; Sedighi, M. [Iran University, Tehran (Iran, Islamic Republic of)

    2016-04-15

    Recently, Variable gutter technique has been introduced as a novel method in order to reduce waste materials in closed-die forging processes. In this paper, the capability of this method is investigated for a family of forged parts that the vertical flow of material is the last stage of forming process. As a case study, using the variable gutter technique, the amount of waste material is decreased about 50% for a sample forged part with a local rising. The results of FVM simulations and experiments confirmed the effectiveness of the variable gutter technique in such forging processes. The vertical flow of material in the die cavity (h parameter), as a criterion, for different gutter width and thickness dimensions was examined by FVM simulations. The results shown that the gutter thickness has more effect on vertical flow of material than the gutter width. By decreasing the gutter thickness and increasing the gutter width, the amount of vertical flow of material is increased about 120% and 29%, respectively. Finally, A/H ratio (A = Max width of sectional area of a forged part, H = Max height of a forged part) is proposed as shape complexity factor of a forged part. The results of FVM simulations are indicated that for the ratio of A/H > 2, the variable gutter thickness technique is more effective and can be successfully used to reduce the amount of waste materials.

  7. Analysis and Optimization of Section-Thickness of the Manipulator for GIS Detection

    Directory of Open Access Journals (Sweden)

    Su Shuangyan

    2016-01-01

    Full Text Available In order to find out the influence of different section-thickness of the manipulator for GIS detection on the mass, strength and stiffness, the performance of the arm rod with different section thickness is analysed by MATLAB under the condition of a certain section height. Firstly, the influence of the parameters of each section-thickness on the mass, strength and stiffness is analysed by single variable analysis. Then the mathematical model is established, and the section-thickness of the arm is optimized using the method of nonlinear programming. The results are similar to the results of single variable analysis. Finally, the section thickness of the virtual prototype is optimized by the finite element analysis method. The correctness of MATLAB optimization results is verified. The optimal solution of the section-thickness of the GIS-detection-arm is obtained.

  8. Manufacturing of Precision Forgings by Radial Forging

    Science.gov (United States)

    Wallner, S.; Harrer, O.; Buchmayr, B.; Hofer, F.

    2011-01-01

    Radial forging is a multi purpose incremental forging process using four tools on the same plane. It is widely used for the forming of tool steels, super alloys as well as titanium- and refractory metals. The range of application goes from reducing the diameters of shafts, tubes, stepped shafts and axels, as well as for creating internal profiles for tubes in Near-Net-Shape and Net-Shape quality. Based on actual development of a weight optimized transmission input shaft, the specific features of radial forging technology is demonstrated. Also a Finite Element Model for the simulation of the process is shown which leads to reduced pre-processing effort and reduced computing time compared to other published simulation methods for radial forging. The finite element model can be applied to quantify the effects of different forging strategies.

  9. Dorsiflexor muscle-group thickness in children with cerebral palsy: Relation to cross-sectional area

    DEFF Research Database (Denmark)

    Bandholm, Thomas; Magnusson, Peter; Jensen, Bente R;

    2009-01-01

    If the thickness and cross-sectional area of the dorsiflexor muscle group are related in children with cerebral palsy, measurements of muscle thickness may be used to monitor changes in muscle size due to training or immobilisation in these patients. We assessed the validity and reliability...... of measurements of dorsiflexor muscle-thickness using the cross-sectional area of the muscle group as the criterion-related muscle-size variable. Muscle thickness was measured using ultrasound, and cross-sectional area using MRI in nine children with spastic cerebral palsy (eight with hemiplegia). Test......-retest reliability of the muscle-thickness measurements was assessed in six healthy subjects. All measurements were made on both legs at 35% lower leg length. In the children with cerebral palsy, dorsiflexor muscle-thickness and cross-sectional area were well correlated (r;{2} = 0.778, P

  10. Friction Stir Welding of Thick Section Aluminum for Military Vehicle Applications

    Science.gov (United States)

    2012-12-01

    Friction Stir Welding of Thick Section Aluminum for Military Vehicle Applications by Brian Thompson, Kevin Doherty, Craig Niese, Mike Eff...International Symposium on Friction Stir Welding (9ISFSW), Huntsville, AL, 15–17 May 2012. Approved for public release...Aberdeen Proving Ground, MD 21005-5069 ARL-RP-417 December 2012 Friction Stir Welding of Thick Section Aluminum for Military

  11. Comparison of scar thickness measurements using trans-vaginal sonography and MRI in cases of pregnancy with previous caesarean section. Do they correlate with actual scar thickness?

    Science.gov (United States)

    Singh, N; Tripathi, R; Mala, Y M; Dixit, R; Tyagi, S; Batra, A

    2013-11-01

    The aim of this study was to evaluate scar thickness in cases of pregnancy with previous caesarean section, by trans-vaginal sonography (TVS) and magnetic resonance imaging (MRI), and to correlate precision of radiologically-measured scar thickness with actual measurement of scar thickness. A total of 35 pregnant patients with previous caesarean section planned for elective caesarean section, were evaluated prospectively. Their scar thickness was measured by TVS and MRI on the day of elective repeat caesarean section. These measurements were correlated with each other and with scar thickness measured during elective repeat caesarean section by using a caliper. The correlation coefficients between scar thickness measured by TVS and MRI with peroperative evaluation with a caliper, were +0.72 and +0.59, respectively. The study concluded that as MRI is a costlier modality and TVS has better correlation coefficient with actual scar thickness, TVS can be considered to be the better modality for antenatal scar thickness measurement.

  12. Section thickness-dependent tensile properties of squeeze cast magnesium alloy AM60

    Directory of Open Access Journals (Sweden)

    Xuezhi Zhang

    2012-05-01

    Full Text Available The development of alternative casting processes is essential for the high demand of light weight magnesium components to be used in the automotive industry, which often contain different section thicknesses. Squeeze casting with its inherent advantages has been approved for the capability of minimizing the gas porosity in magnesium alloys. For advanced engineering design of light magnesium automotive applications, it is critical to understand the effect of section thickness on mechanical properties of squeeze cast magnesium alloys. In this study, magnesium alloy AM60 with different section thicknesses of 6, 10 and 20 mm squeeze cast under an applied pressure of 30 MPa was investigated. The prepared squeeze cast AM60 specimens were tensile tested at room termperature. The results indicate that the mechanical properties including yield strength (YS, ultimate tensile strength (UTS and elongation (A decrease with an increase in section thickness of squeeze cast AM60. The microstructure analysis shows that the improvement in the tensile behavior of squeeze cast AM60 is primarily attributed to the low-gas porosity level and fine grain strucuture which result from the variation of cooling rate of different section thickness. The numerical simulation (Magmasoft? was employed to determine the solidification rates of each step, and the simulated results show that the solidification rate of the alloy decreases with an increase in the section thickness. The computed solidification rates support the experimental observation on grain structural development.

  13. Influence of Section Thickness on Microstructure and Mechanical Properties of Squeeze Cast Magnesium Alloy AM60

    Science.gov (United States)

    Zhang, Xuezhi; Wang, Meng; Sun, Zhizhong; Hu, Henry

    Squeeze cast light alloys has been approved for advanced engineering design of light integrity automotive applications. An understanding of the effect of section thicknesses on mechanical properties of squeeze cast magnesium alloys is essential for proper design of different applications. The present work studied the microstructure and tensile properties of magnesium alloy AM60 with different section thickness of 6, 10 and 20mm squeeze cast under an applied pressure of 30MPa. The results of tensile testing indicate that the yield strength (YS), ultimate tensile strength (UTS) and elongation (Ef) increase with a decreasing in section thicknesses of squeeze cast AM60. The microstructure analysis shows that the improvement in the tensile properties of squeeze cast AM60 is mainly attributed to the low level of gas porosity and the high content of eutectic phases and fine grain structure which resulted from high solidification rates taking place in the thin section.

  14. CHOROIDAL THICKNESS IN UNILATERAL IDIOPATHIC MACULAR HOLE: A Cross-Sectional Study and Meta-Analysis.

    Science.gov (United States)

    Zhang, Pengfei; Zhou, Minwen; Wu, Ying; Lu, Bing; Li, Tong; Zhao, Jingke; Wang, Fenghua; Sun, Xiaodong

    2017-01-01

    To investigate the choroidal thickness in unilateral idiopathic macular hole (IMH) eyes and compare them with normal control eyes using enhanced depth imaging optical coherence tomography (EDI-OCT). In this cross-sectional study, the subfoveal choroidal thickness (SFCT) and choroidal thickness at 1 mm and 3 mm nasal, temporal, superior, and inferior to the fovea of IMH eyes and normal control eyes were measured using EDI-OCT. Univariate and multivariate linear regression analyses were performed to evaluate the correlation between choroidal thickness at various locations and clinical factors. A meta-analysis was conducted using the Stata software package to calculate the summary of weighted mean differences (WMDs). Thirty-two unilateral IMH patients and 32 controls were enrolled in this study. The IMH eyes had a thinner choroid than the control eyes at all macular locations (all P choroidal thickness at any of the nine points was significantly thinner in association with the IMH diagnosis, as well as being somewhat thinner in association with age and axial length. The result of our cross-sectional study was consistent with the meta-analysis with a pooled WMD of -56.99 (95% confidence interval [CI]: -68.58 to -45.41) for subfoveal choroidal thickness. The study of Chinese unilateral IMH patients, along with the comprehensive meta-analysis, suggested that the choroidal thickness at all macular locations in unilateral IMH eyes significantly decreased relative to the control group.

  15. Analysis of reforming process of large distorted ring in final enlarging forging

    Energy Technology Data Exchange (ETDEWEB)

    Miyazawa, Takeshi; Murai, Etsuo [Kushiro National College of Technology, Dept. of Mechanical Engineering, Kushiro, Hokkaido (Japan)

    2002-10-01

    In the construction of reactors or pressure vessels for oil chemical plants and nuclear power stations, mono block open-die forging rings are often utilized. Generally, a large forged ring is manufactured by means of enlarging forging with reductions of the wall thickness. During the enlarging process the circular ring is often distorted and becomes an ellipse in shape. However the shape control of the ring is a complicated work. This phenomenon makes the matter still worse in forging of larger rings. In order to make precision forging of large rings, we have developed the forging method using a v-shape anvil. The v-shape anvil is geometrically adjusted to fit the distorted ring in the final circle and reform automatically the shape of the ring during enlarging forging. This paper has analyzed the reforming process of distorted ring by computer program based on F.E.M. and examined the effect on the precision of ring forging. (author)

  16. Three-dimensional direct measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections.

    Science.gov (United States)

    Bensley, Jonathan Guy; De Matteo, Robert; Harding, Richard; Black, Mary Jane

    2016-01-01

    Quantitative assessment of myocardial development and disease requires accurate measurement of cardiomyocyte volume, nuclearity (nuclei per cell), and ploidy (genome copies per cell). Current methods require enzymatically isolating cells, which excludes the use of archived tissue, or serial sectioning. We describe a method of analysis that permits the direct simultaneous measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections. To demonstrate the utility of our technique, heart tissue was obtained from four species (rat, mouse, rabbit, sheep) at up to three life stages: prenatal, weaning and adulthood. Thick (40 μm) paraffin sections were stained with Wheat Germ Agglutinin-Alexa Fluor 488 to visualise cell membranes, and DAPI (4',6-diamidino-2-phenylindole) to visualise nuclei and measure ploidy. Previous methods have been restricted to thin sections (2-10 μm) and offer an incomplete picture of cardiomyocytes. Using confocal microscopy and three-dimensional image analysis software (Imaris Version 8.2, Bitplane AG, Switzerland), cardiomyocyte volume, nuclearity, and ploidy were measured. This method of staining and analysis of cardiomyocytes enables accurate morphometric measurements in thick histological sections, thus unlocking the potential of archived tissue. Our novel time-efficient method permits the entire cardiomyocyte to be visualised directly in 3D, eliminating the need for precise alignment of serial sections.

  17. Three-dimensional direct measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections

    Science.gov (United States)

    Bensley, Jonathan Guy; de Matteo, Robert; Harding, Richard; Black, Mary Jane

    2016-04-01

    Quantitative assessment of myocardial development and disease requires accurate measurement of cardiomyocyte volume, nuclearity (nuclei per cell), and ploidy (genome copies per cell). Current methods require enzymatically isolating cells, which excludes the use of archived tissue, or serial sectioning. We describe a method of analysis that permits the direct simultaneous measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections. To demonstrate the utility of our technique, heart tissue was obtained from four species (rat, mouse, rabbit, sheep) at up to three life stages: prenatal, weaning and adulthood. Thick (40 μm) paraffin sections were stained with Wheat Germ Agglutinin-Alexa Fluor 488 to visualise cell membranes, and DAPI (4‧,6-diamidino-2-phenylindole) to visualise nuclei and measure ploidy. Previous methods have been restricted to thin sections (2–10 μm) and offer an incomplete picture of cardiomyocytes. Using confocal microscopy and three-dimensional image analysis software (Imaris Version 8.2, Bitplane AG, Switzerland), cardiomyocyte volume, nuclearity, and ploidy were measured. This method of staining and analysis of cardiomyocytes enables accurate morphometric measurements in thick histological sections, thus unlocking the potential of archived tissue. Our novel time-efficient method permits the entire cardiomyocyte to be visualised directly in 3D, eliminating the need for precise alignment of serial sections.

  18. Thick-target transmission method for excitation functions of interaction cross sections

    CERN Document Server

    Aikawa, M; Imai, S

    2016-01-01

    We propose a method, called as thick-target transmission (T3) method, to obtain an excitation function of interaction cross sections. In an ordinal experiment to measure the excitation function of interaction cross sections by the transmission method, we need to change the beam energy for each cross section. In the T3 method, the excitation function is derived from the beam attenuations measured at the targets of different thicknesses without changing the beam energy. The advantage of the T3 method is the simplicity and availability for radioactive beams. To confirm the availability, we perform a simulation for the 12C+27Al system with the PHITS code instead of actual experiments. Our results have large uncertainties but well reproduce the tendency of the experimental data.

  19. Estimating the thickness of ultra thin sections for electron microscopy by image statistics

    DEFF Research Database (Denmark)

    Sporring, Jon; Khanmohammadi, Mahdieh; Darkner, Sune

    2014-01-01

    We propose a method for estimating the thickness of ultra thin histological sections by image statistics alone. Our method works for images, that are the realisations of a stationary and isotropic stochastic process, and it relies on the existence of statistical image-measures that are strictly...... monotonic with distance. We propose to use the standard deviation of the difference between pixel values as a function of distance, and we give an extremely simple, linear algorithm. Our algorithm is applied to the challenging domain of electron microscopic sections supposedly $45\\text{ nm}$ apart, and we...

  20. Thick methacrylate sections devoid of lost caps simplify stereological quantifications based on the optical fractionator design

    DEFF Research Database (Denmark)

    Andersen, Stine Hasselholt; Lykkesfeldt, Jens; Larsen, Jytte Overgaard

    2015-01-01

    Abstract In neuroscience, the optical fractionator technique is frequently used for unbiased cell number estimations. Although unbiased in theory, the practical application of the technique is often biased by the necessity of introducing a guard zone at one side of the disector to counter lost caps...... methacrylate) sections were inspected for lost caps to evaluate the possibility of whole section thickness counting with the optical fractionator technique and hippocampal granular cell nucleoli density differences along the z-axis were assessed with a z-axis analysis. No lost caps were found in the examined...

  1. Modeling of Closed-Die Forging for Estimating Forging Load

    Science.gov (United States)

    Sheth, Debashish; Das, Santanu; Chatterjee, Avik; Bhattacharya, Anirban

    2017-02-01

    Closed die forging is one common metal forming process used for making a range of products. Enough load is to exert on the billet for deforming the material. This forging load is dependent on work material property and frictional characteristics of the work material with the punch and die. Several researchers worked on estimation of forging load for specific products under different process variables. Experimental data on deformation resistance and friction were used to calculate the load. In this work, theoretical estimation of forging load is made to compare this value with that obtained through LS-DYNA model facilitating the finite element analysis. Theoretical work uses slab method to assess forging load for an axi-symmetric upsetting job made of lead. Theoretical forging load estimate shows slightly higher value than the experimental one; however, simulation shows quite close matching with experimental forging load, indicating possibility of wide use of this simulation software.

  2. The State of the Art in Cold Forging Lubrication

    DEFF Research Database (Denmark)

    Bay, Niels

    1994-01-01

    the conversion coatings are based on zinc phosphates but different requirements to the coating properties have to be met in different cold forging operations. This is obtained by adopting different oxidants leading to different composition, layer thickness and morphology of the conversion coatings. Concerning...... a detailed description of the state of art for lubricant systems for cold forging of C-steels and low alloy steels as well as aluminium alloys including all the basic operations such as cleaning of the slugs, application of eventual conversion coating and lubrication. As regards cold forging of steel...... aluminium unalloyed and softer alloys like the AA 1000, 3000 and 6000 series can be cold forged with either grease, oil or zinc stearate whereas the harder alloys from series AA 2000, 5000 and 7000 require a conversion coating to carry the lubricant. Three different types of conversion coating are described...

  3. Effect of annealing, thickness ratio and bend angle on springback of AA6061-T6 with non-uniform thickness section

    Directory of Open Access Journals (Sweden)

    Adnan M.F.

    2017-01-01

    Full Text Available Non-uniform thickness section section is considered one of the most effective approaches to reduce automotive part weight. Reduction in term of mass and size result in less fuel consumption and greenhouse gases. Thickness is the most significant parameter to formability, therefore forming a section with non-uniform thickness becomes a great challenge. Improper process and incorrect decision may lead to severe defect and one of the main concerns is the springback. This study will focus on springback behaviour of non-uniform thickness AA6061 strip with complex profile using Taguchi Method. Profile projector (PC 3000 is used to measure the spring back and two-line technique is applied to measure angles (after loading between two lines. Three parameters (i.e. annealing temperature, thickness ratio and bend angle are studied, and results determine that the most significant parameter is bend angle, followed by thickness ratio, and then by the annealing temperature of the specimen during bending process.

  4. The new forging process of a wheel hub drop forging

    OpenAIRE

    A. Gontarz

    2006-01-01

    Purpose: The main purpose of the research was working out a new flashless forming process of wheel hubforging in three-slide forging press (TSFP). It was assumed that the new process would be more effective thanthe forging processes applied in typical forging machines.Design/methodology/approach: The designing of the new process was based on the simulation by finiteelement method with the assumption of 3D state of strain. Calculations were made mainly for the analysis of thematerial flow kine...

  5. Simulated lesion, human observer performance comparison between thin-section dedicated breast CT images versus computed thick-section simulated projection images of the breast

    Science.gov (United States)

    Chen, L.; Boone, J. M.; Abbey, C. K.; Hargreaves, J.; Bateni, C.; Lindfors, K. K.; Yang, K.; Nosratieh, A.; Hernandez, A.; Gazi, P.

    2015-04-01

    The objective of this study was to compare the lesion detection performance of human observers between thin-section computed tomography images of the breast, with thick-section (>40 mm) simulated projection images of the breast. Three radiologists and six physicists each executed a two alterative force choice (2AFC) study involving simulated spherical lesions placed mathematically into breast images produced on a prototype dedicated breast CT scanner. The breast image data sets from 88 patients were used to create 352 pairs of image data. Spherical lesions with diameters of 1, 2, 3, 5, and 11 mm were simulated and adaptively positioned into 3D breast CT image data sets; the native thin section (0.33 mm) images were averaged to produce images with different slice thicknesses; average section thicknesses of 0.33, 0.71, 1.5 and 2.9 mm were representative of breast CT; the average 43 mm slice thickness served to simulate simulated projection images of the breast. The percent correct of the human observer’s responses were evaluated in the 2AFC experiments. Radiologists lesion detection performance was significantly (p physicist observer, however trends in performance were similar. Human observers demonstrate significantly better mass-lesion detection performance on thin-section CT images of the breast, compared to thick-section simulated projection images of the breast.

  6. The new forging process of a wheel hub drop forging

    Directory of Open Access Journals (Sweden)

    A. Gontarz

    2006-08-01

    Full Text Available Purpose: The main purpose of the research was working out a new flashless forming process of wheel hubforging in three-slide forging press (TSFP. It was assumed that the new process would be more effective thanthe forging processes applied in typical forging machines.Design/methodology/approach: The designing of the new process was based on the simulation by finiteelement method with the assumption of 3D state of strain. Calculations were made mainly for the analysis of thematerial flow kinematics and the process loads parameters. Experimental research were also made determiningthe dependency of clamping load in the function of forming load. On the basis of the analysis, the formingprocess of a wheel hub drop forging on the TSFP was worked out.Findings: The results of research confirmed the possibility of flashless forming process of wheel hub forgingin TSFP with axial cavities. The main parameters limiting the forming processes of wheel hub forgings are:permissible upsetting ratio and reciprocal relation of forming and clamping forces.Research limitations/implications: The further research within the range of determining force parameters fordifferent types of material and schemata of forming in TSFP were considered as purposeful. The works dealingwith analysis of forming processes of different types of products in order to classify drop forgings possible toform in this press will be examined.Practical implications: The comparison of the new forming process with the forging process on hammershowed majority of advantages which include: decrease of time and energy, decrease of drop forging weight andmachining, decrease of material consumption.Originality/value: The new process of wheel hub forging forming with axial cavities was worked out. Theparameters important during designing of forming processes in TSFP were provided. The relations betweenforces of forming tools were also determined.

  7. Immunoperoxidase detection of neuronal antigens in full-thickness whole mount preparations of hollow organs and thick sections of central nervous tissue.

    Science.gov (United States)

    Llewellyn-Smith, Ida J; Gnanamanickam, Greta J E

    2011-03-15

    Immunofluorescently stained whole mounts have proved useful for defining the innervation of the gut and large blood vessels. Nerves supplying other hollow organs are usually studied in sections, which provide much less information. Aiming to describe the entire innervation of rat uterus, we developed a method for immunoperoxidase staining of full-thickness whole mounts that allowed us to visualize all immunoreactive axons. Uterine horns were dissected out, slit open, stretched, pinned flat and fixed. Entire horns were treated with methanol/peroxide, buffered Triton X-100 and normal serum and then incubated in primary antibodies, biotinylated secondary antibodies and avidin-horseradish peroxidase (HRP), each for at least 3 days. Peroxidase reactions revealed immunoreactivity. Immunostained horns were dehydrated, infiltrated with epoxy resin, mounted on slides under Aclar coverslips and polymerized. We treated bladders, gut, major pelvic ganglia and thick sections of perfused medulla oblongata similarly to assess the applicability of the method. Using this method, we could map the entire uterine innervation provided by axons immunoreactive for a variety of antigens. We could also assess the entire tyrosine hydroxylase-immunoreactive innervation in all layers of bladder, gut and ganglia whole mounts and throughout 300 μm sections of medulla. These observations show that this method for immunoperoxidase staining reliably reveals the complete innervation of full-thickness whole mounts of hollow organs and thick sections of central nervous tissue. The method has several advantages. The resin-embedded tissue does not degrade; the immunostaining is non-fading and permanent and neurochemically defined features can be mapped at large scale without confocal microscopy.

  8. Greater Cortical Thickness in Elderly Female Yoga Practitioners-A Cross-Sectional Study.

    Science.gov (United States)

    Afonso, Rui F; Balardin, Joana B; Lazar, Sara; Sato, João R; Igarashi, Nadja; Santaella, Danilo F; Lacerda, Shirley S; Amaro, Edson; Kozasa, Elisa H

    2017-01-01

    Yoga, a mind-body activity that requires attentional engagement, has been associated with positive changes in brain structure and function, especially in areas related to awareness, attention, executive functions and memory. Normal aging, on the other hand, has also been associated with structural and functional brain changes, but these generally involve decreased cognitive functions. The aim of this cross-sectional study was to compare brain cortical thickness (CT) in elderly yoga practitioners and a group of age-matched healthy non-practitioners. We tested 21 older women who had practiced hatha yoga for at least 8 years and 21 women naive to yoga, meditation or any mind-body interventions who were matched to the first group in age, years of formal education and physical activity level. A T1-weighted MPRAGE sequence was acquired for each participant. Yoga practitioners showed significantly greater CT in a left prefrontal lobe cluster, which included portions of the lateral middle frontal gyrus, anterior superior frontal gyrus and dorsal superior frontal gyrus. We found greater CT in the left prefrontal cortex of healthy elderly women who trained yoga for a minimum of 8 years compared with women in the control group.

  9. Greater Cortical Thickness in Elderly Female Yoga Practitioners—A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Rui F. Afonso

    2017-06-01

    Full Text Available Yoga, a mind-body activity that requires attentional engagement, has been associated with positive changes in brain structure and function, especially in areas related to awareness, attention, executive functions and memory. Normal aging, on the other hand, has also been associated with structural and functional brain changes, but these generally involve decreased cognitive functions. The aim of this cross-sectional study was to compare brain cortical thickness (CT in elderly yoga practitioners and a group of age-matched healthy non-practitioners. We tested 21 older women who had practiced hatha yoga for at least 8 years and 21 women naive to yoga, meditation or any mind-body interventions who were matched to the first group in age, years of formal education and physical activity level. A T1-weighted MPRAGE sequence was acquired for each participant. Yoga practitioners showed significantly greater CT in a left prefrontal lobe cluster, which included portions of the lateral middle frontal gyrus, anterior superior frontal gyrus and dorsal superior frontal gyrus. We found greater CT in the left prefrontal cortex of healthy elderly women who trained yoga for a minimum of 8 years compared with women in the control group.

  10. Layer Additive Production or Manufacturing of Thick Sections of Ti-6Al-4V by Selective Electron Beam Melting (SEBM)

    Science.gov (United States)

    Sun, Y. Y.; Gulizia, S.; Fraser, D.; Oh, C. H.; Lu, S. L.; Qian, M.

    2017-07-01

    Selective electron beam melting (SEBM) is an established layer additive manufacturing or production process for small-to-medium-sized components of Ti-6Al-4V. Current literature data on SEBM of Ti-6Al-4V are, however, based principally on thin-section (<1″; mostly <0.5″) samples or components. In this research, 34-mm-thick (1.34″) Ti-6Al-4V block samples were produced through use of default Arcam SEBM parameters and characterized versus section thickness. High densities (99.4-99.8%) were achieved across different thick sections, but markedly inhomogeneous microstructures also developed. Nonetheless, the tensile properties measured from 27 different thickness-width positions all clearly satisfied the minimum requirements for mill-annealed Ti-6Al-4V. SEBM produced highly dense thick sections of Ti-6Al-4V with good tensile properties. Large lack-of-fusion defects (80-250 µm) were found to be mainly responsible for variations in tensile properties.

  11. Age effects on cortical thickness in young Down's syndrome subjects: a cross-sectional gender study

    Energy Technology Data Exchange (ETDEWEB)

    Romano, Andrea; Moraschi, Marta [San Raffaele Foundation Rome, Rehabilitation Facility Ceglie Messapica, Rome (Italy); Cornia, Riccardo; Stella, Giacomo [University of Modena and Reggio Emilia, Department of Education and Human Sciences, Emilia-Romagna (Italy); Bozzao, Alessandro; Gagliardo, Olga [University Sapienza, NESMOS, Department of Neuroradiology, S. Andrea Hospital, Rome (Italy); Chiacchiararelli, Laura [University Sapienza, Department of Medical Physics, S. Andrea Hospital, Rome (Italy); Iani, Cristina [University of Modena and Reggio Emilia, Department of Communication and Economy, Emilia-Romagna (Italy); Albertini, Giorgio [IRCSS San Raffaele Pisana, Department of Paediatrics, Rome (Italy); Pierallini, Alberto [IRCSS San Raffaele Pisana, Department of Radiology, Rome (Italy)

    2015-04-01

    The aim of this study was to determine differences in the characteristic pattern of age-related cortical thinning in men and women with Down's syndrome (DS) by means of MRI and automatic cortical thickness measurements and a cross-sectional design, in a large cohort of young subjects. Eighty-four subjects with DS, 30 females (11-35 years, mean age ± SD = 22.8 ± 5.9) and 54 males (11-35 years, mean age ± SD = 21.5 ± 6.5), were examined using a 1.5-T scanner. MRI-based quantification of cortical thickness was performed using FreeSurfer software package. For all subjects participating in the study, the Pearson product-moment correlation coefficient between age and mean cortical thickness values has been evaluated. A significant negative correlation between cortical thickness and age was found in female DS subjects, predominantly in frontal and parietal lobes, bilaterally. In male DS subjects, a significant negative correlation between cortical thickness and age was found in the right fronto-temporal lobes and cingulate regions. Whole brain mean cortical thickness values were significantly negative correlated with age only in female DS subjects. Females with Down's syndrome showed a strong correlation between cortical thickness and age, already in early age. We suggest that the cognitive impairment due to hormonal deficit in the postmenopausal period could be emphasized by the early structural decline of gray matter in female DS subjects. (orig.)

  12. Simulation and analysis of hot forging process for industrial locking gear elevators

    Science.gov (United States)

    Maarefdoust, M.; Kadkhodayan, M.

    2010-06-01

    In this paper hot forging process for industrial locking gear elevators is simulated and analyzed. An increase in demand of industrial locking gear elevators with better quality and lower price caused the machining process to be replaced by hot forging process. Production of industrial locking gear elevators by means of hot forging process is affected by many parameters such as billet temperature, geometry of die and geometry of pre-formatted billet. In this study the influences of billet temperature on effective plastic strain, radius of die corners on internal stress of billet and thickness of flash on required force of press are investigated by means of computer simulation. Three-dimensional modeling of initial material and die are performed by Solid Edge, while simulation and analysis of forging are performed by Super Forge. Based on the computer simulation the required dies are designed and the workpieces are formed. Comparison of simulation results with experimental data demonstrates great compatibility.

  13. The effects of section thickness on the estimation of liver volume by the Cavalieri principle using computed tomography images

    Energy Technology Data Exchange (ETDEWEB)

    Emirzeoglu, Mehmet [Department of Anatomy, Medical School, Ondokuz Mayis University, Samsun 55139 (Turkey); Sahin, Bunyamin [Department of Anatomy, Medical School, Ondokuz Mayis University, Samsun 55139 (Turkey)]. E-mail: bsahin@omu.edu.tr; Selcuk, Mustafa B. [Department of Radiology, Medical School, Ondokuz Mayis University, Samsun 55139 (Turkey); Kaplan, Suleyman [Department of Histology and Embryology, Medical School, Ondokuz Mayis University, Samsun 55139 (Turkey)

    2005-12-15

    Estimation of liver volume using routine CT scans has been described previously. We have, however, not found a gold standard study which analyzes the effect of section thickness on the estimation of liver volume using CT images. In the present study, five normal livers obtained from cadavers were scanned using a Spiral CT Scanner (Xpress/GX Toshiba, Tocigi-Ken) in the horizontal plane. Consecutive sections at a thickness of 10, 5 and 1 mm were used to estimate the total volume of the livers by means of the Cavalieri principle. With a view to evaluating inter-observer differences, liver volume was estimated by three observers. The estimated volume using the classical volume estimation formula did not concur with the actual volume of the livers obtained by the fluid displacement technique. The section thickness has an over- or under-projection effect on the estimated volume. The obtained volume estimation results were, therefore, calibrated using three different approaches. The volume obtained by the calibration formulae did not differ statistically from actual liver volumes (P < 0.05). There were also no significant differences between the performers' estimates (P > 0.05). Results showed that the effect of section thickness on the volume estimates could not be omitted and the obtained values could be calibrated using the proposed approaches presented in this study.

  14. Assessment of Macular Thickness in Healthy Eyes Using Cirrus HD-OCT: A Cross-Sectional Study.

    Science.gov (United States)

    Sabouri, Mohammad Rasoul; Kazemnezhad, Ehsan; Hafezi, Vahideh

    2016-01-01

    We aimed to determine normal macular thickness using Cirrus high definition optical coherence tomography. In this cross-sectional survey, 112 subjects were selected using random sampling from the Rasht telephone directory. All subjects underwent complete eye examinations. Both eyes of each patient were evaluated. The creation of a macular thickness map using a macular cube 512 × 128 combo was optional. The average thickness of the retina was determined in 9 Early Treatment Diabetic Retinopathy Study (ETDRS) regions. To assess reproducibility and system reliability, the thickness of the retina was measured up to 5 times in 10 healthy subjects. The coefficient of variation was then calculated for each individual. The coefficient of variation of macular thickness within 1 mm of the center was 0.15 - 1.33%. The means and standard deviations of central subfield thickness (CST), macular thickness (MT), and macular volume (MV) were 245.44 ± 20.39 µm, 277.9 ± 12.0 µm, and 9.98 ± 0.43 mm(3), respectively. The mean CST (P < 0.0001), MT (P = 0.038), and MV (P = 0.030) were significantly higher in men than in women. In addition, regardless of age or sex, macular thickness increased when moving from within 1 mm of the center to 3 mm and 6 mm away from the center, so that the upper 3 mm (S3) was the thickest region, and the temporal 6 mm (T6) was the thinnest region in the ETDRS regions. The mean MT of healthy subjects was 280.67 ± 12.79 µm in men and 276.63 ± 11.61 µm in women. Therefore, the macula is significantly thicker in men than in women (P = 0.038).

  15. Brain BLAQ: Post-hoc thick-section histochemistry for localizing optogenetic constructs in neurons and their distal terminals.

    Science.gov (United States)

    Kupferschmidt, David A; Cody, Patrick A; Lovinger, David M; Davis, Margaret I

    2015-01-01

    Optogenetic constructs have revolutionized modern neuroscience, but the ability to accurately and efficiently assess their expression in the brain and associate it with prior functional measures remains a challenge. High-resolution imaging of thick, fixed brain sections would make such post-hoc assessment and association possible; however, thick sections often display autofluorescence that limits their compatibility with fluorescence microscopy. We describe and evaluate a method we call "Brain BLAQ" (Block Lipids and Aldehyde Quench) to rapidly reduce autofluorescence in thick brain sections, enabling efficient axon-level imaging of neurons and their processes in conventional tissue preparations using standard epifluorescence microscopy. Following viral-mediated transduction of optogenetic constructs and fluorescent proteins in mouse cortical pyramidal and dopaminergic neurons, we used BLAQ to assess innervation patterns in the striatum, a region in which autofluorescence often obscures the imaging of fine neural processes. After BLAQ treatment of 250-350 μm-thick brain sections, axons and puncta of labeled afferents were visible throughout the striatum using a standard epifluorescence stereomicroscope. BLAQ histochemistry confirmed that motor cortex (M1) projections preferentially innervated the matrix component of lateral striatum, whereas medial prefrontal cortex projections terminated largely in dorsal striosomes and distinct nucleus accumbens subregions. Ventral tegmental area dopaminergic projections terminated in a similarly heterogeneous pattern within nucleus accumbens and ventral striatum. Using a minimal number of easily manipulated and visualized sections, and microscopes available in most neuroscience laboratories, BLAQ enables simple, high-resolution assessment of virally transduced optogenetic construct expression, and post-hoc association of this expression with molecular markers, physiology and behavior.

  16. Instant forgedUI starter

    CERN Document Server

    Luiz, Joseandro

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks.The book is a Starter guide to learning ForgedUI. This book will start by unfolding the installation and creating a simple application using Titanium and ForgedUI, followed by taking you through the features to model an engaging UI and generate multi-platform code with Titanium, while covering the best design practice for Apple and Android application development. Last but not least, you will also come across the available resources where you can

  17. Confocal Microscopy of thick tissue sections: 3D Visualization of rat kidney glomeruli

    Science.gov (United States)

    Confocal laser scanning microscopy (CLSM) as a technique capable of generating serial sections of whole-mount tissue and then reassembling the computer-acquired images as a virtual 3-dimentional structure. In many ways CLSM offers an alternative to traditional sectioning approac...

  18. Confocal microscopy of thick tissue sections: 3D visualizaiton of rat kidney glomeruli

    Science.gov (United States)

    Confocal laser scanning microscopy (CLSM) as a technique capable of generating serial sections of whole-mount tissue and then reassembling the computer-acquired images as a virtual 3-dimentional structure. In many ways CLSM offers an alternative to traditional sectioning approac...

  19. Confocal microscopy of thick tissue sections: 3D visualizaiton of rat kidney glomeruli

    Science.gov (United States)

    Confocal laser scanning microscopy (CLSM) as a technique capable of generating serial sections of whole-mount tissue and then reassembling the computer-acquired images as a virtual 3-dimentional structure. In many ways CLSM offers an alternative to traditional sectioning approac...

  20. Confocal Microscopy of thick tissue sections: 3D Visualization of rat kidney glomeruli

    Science.gov (United States)

    Confocal laser scanning microscopy (CLSM) as a technique capable of generating serial sections of whole-mount tissue and then reassembling the computer-acquired images as a virtual 3-dimentional structure. In many ways CLSM offers an alternative to traditional sectioning approac...

  1. Dark adaptation in relation to choroidal thickness in healthy young subjects: a cross-sectional, observational study.

    Science.gov (United States)

    Munch, Inger Christine; Altuntas, Cigdem; Li, Xiao Qiang; Jackson, Gregory R; Klefter, Oliver Niels; Larsen, Michael

    2016-07-11

    Dark adaptation is an energy-requiring process in the outer retina nourished by the profusely perfused choroid. We hypothesized that variations in choroidal thickness might affect the rate of dark adaptation. Cross-sectional, observational study of 42 healthy university students (mean age 25 ± 2.0 years, 29 % men) who were examined using an abbreviated automated dark adaptometry protocol with a 2° diameter stimulus centered 5° above the point of fixation. The early, linear part of the rod-mediated dark adaptation curve was analyzed to extract the time required to reach a sensitivity of 5.0 × 10(-3) cd/m2 (time to rod intercept) and the slope (rod adaptation rate). The choroid was imaged using enhanced-depth imaging spectral-domain optical coherence tomography (EDI-OCT). The time to the rod intercept was 7.3 ± 0.94 (range 5.1 - 10.2) min. Choroidal thickness 2.5° above the fovea was 348 ± 104 (range 153-534) μm. There was no significant correlation between any of the two measures of rod-mediated dark adaptation and choroidal thickness (time to rod intercept versus choroidal thickness 0.072 (CI95 -0.23 to 0.38) min/100 μm, P = 0.64, adjusted for age and sex). There was no association between the time-to-rod-intercept or the dark adaptation rate and axial length, refraction, gender or age. Choroidal thickness, refraction and ocular axial length had no detectable effect on rod-mediated dark adaptation in healthy young subjects. Our results do not support that variations in dark adaptation can be attributed to variations in choroidal thickness.

  2. Powder Metallurgy Forged Gear Development

    Science.gov (United States)

    1985-03-01

    Unclassified) 12. PERSONAL AUTHOR(S) D. H. Ro, B. L. Ferguson, S. Pillay, D. T. Ostberg 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year, Month...Method Water Atomized SelecCion -Initial Alloy Distribution Prealloyed -Particle Size Distribution -100 Mesh kForging Quality) Uxmtpaction -Lubricant Zinc

  3. Cross-sectional nanoindentation (CSN) studies on the effect of thickness on adhesion strength of thin films

    Science.gov (United States)

    Roshanghias, A.; Khatibi, G.; Pelzer, R.; Steinbrenner, J.; Bernardi, J.

    2015-01-01

    In this study the cross-sectional nanoindentation (CSN) technique has been employed to investigate the adhesion behavior of Titanium-Tungsten (TiW) thin films in various thicknesses on silicon substrate. Furthermore, the nanoindentation-induced blister (NIB) technique has been implemented on the same samples to evaluate the adhesion energy of the films with a different approach. The adhesion energy release rate of these thin films, derived by these two techniques, revealed a good agreement. Accordingly, the results show that as the thickness of the TiW layer increases, the adhesion toughness of the film decreases. It was suggested that three factors might be responsible for the superior adhesion strength of thin films with lower thicknesses: higher surface energy due to the smaller mean grain size; higher constraint from the substrate, which causes inferior fracture toughness of the coating and facilitates crack deflection from interface to surface; and, energy dissipation due to decohesion. The thickness dependency of the transition between delamination and decohesion mechanism in thin films has also been discussed and modelled.

  4. Closed Die Hammer Forging of Inconel 718

    Directory of Open Access Journals (Sweden)

    S. Chenna Krishna

    2014-01-01

    Full Text Available A method for the production of Inconel 718 (IN-718 hemispherical domes by closed die hammer forging is proposed. Different combination of operations employed for production are as follows: (i preforging + final forging + air cooling, (ii preforging + final forging + controlled cooling, (iii direct forging + controlled cooling, and (iv direct forging + air cooling. Last three combinations yielded a crack free hemispherical dome. The forged hemispherical domes were solution annealed at 980°C for 1 h and air cooled. The grain size of the domes at all locations was finer than ASTM No 4. Mechanical properties of the forged dome in solution treated and aged condition (STA were better than feedstock used.

  5. Predicting total fat mass from skinfold thicknesses in Japanese prepubertal children: a cross-sectional and longitudinal validation.

    Science.gov (United States)

    Midorikawa, Taishi; Ohta, Megumi; Hikihara, Yuki; Torii, Suguru; Bemben, Michael G; Sakamoto, Shizuo

    2011-01-01

    The present study was performed to develop regression based prediction equations for fat mass from skinfold thickness in Japanese children, and to investigate the cross-sectional and longitudinal validity of these equations. A total of 127 healthy Japanese prepubertal children aged 6-12 years were randomly separated into two groups: the model development group (54 boys and 44 girls) and the cross-sectional validation group (18 boys and 11 girls). Fat mass was initially determined by using DXA (Hologic Delphi A-QDR whole-body scanner) to provide reference data. Then, fat thickness was measured at triceps and subscapular using an Eiken-type skinfold calipers. Multiple anthropometric and DXA measures were obtained one year later for 28 of the original 127 subjects (longitudinal validation group: 14 boys and 14 girls). Strong significant correlations were observed between total fat mass by DXA measurement and the skinfold thickness × height measures by caliper in the model development group of boys and girls (R2=0.91-0.92, pSkinfold-derived prediction equations underestimate for obese children but are generally useful for estimating total fat mass in field research.

  6. Fracture behavior of shallow cracks in full-thickness clad beams from an RPV wall section

    Science.gov (United States)

    Keeney, J. A.; Bass, B. R.; McAfee, W. J.

    A testing program is described that utilizes full-thickness clad beam specimens to quantify fracture toughness for shallow cracks in weld material for which metallurgical conditions are prototypic of those found in reactor pressure vessels (RPV's). The beam specimens are fabricated from an RPV shell segment that includes weld, plate and clad material. Metallurgical factors potentially influencing fracture toughness for shallow cracks in the beam specimens include material gradients and material inhomogeneities in welded regions. The shallow-crack clad beam specimens showed a significant loss of constraint similar to that of other shallow-crack single-edge notch bend (SENB) specimens. The stress-based Dodds-Anderson scaling model appears to be effective in adjusting the test data to account for in-plane loss of constraint for uniaxially tested beams, but cannot predict the observed effects of out-of-plane biaxial loading on shallow-crack fracture toughness. A strain-based dual-parameter fracture toughness correlation (based on plastic zone width) performed acceptably when applied to the uniaxial and biaxial shallow-crack fracture toughness data.

  7. RESEARCH ON KNOWLEDGE-BASED CAPP SYSTEM FOR ROTOR FORGING

    Institute of Scientific and Technical Information of China (English)

    Wang Leigang; Deng Dongrnei; Liu Zhubai

    2000-01-01

    Guided by developing forging technology theory,designing rules on rotor forging process are summed up.Knowledge-based CAPP system for rotor forging is created.The system gives a rational and optimum process.

  8. Measurement of the resonance shift in the radar backscattering cross section of thick stainless steel fibers at 35 GHz

    Science.gov (United States)

    Alyones, Sharhabeel; Bruce, Charles

    2007-03-01

    Measurements of the radar backscattering cross section of stainless steel fibers with low length-to-diameter ratio (thick fibers) had been done at 35 GHz. The intention was to confirm the resonance shift in length predicted by a numerical solution of the general problem of electromagnetic scattering and absorption by finite conducting wires [1]. The numerical methods solves the generalized form of the Pocklington equation, which is valid for both thin and thick fibers. Single particle radar backscattering measurement system was used and the resonance shift had been confirmed for four sets of aspect ratios. The position of the first resonance is shifted to shorter lengths in comparison with the previous analytical solution of the problem by P. Watermann and J. Pedersen [2]. [1] Sharhabeel Alyones, Charles W. Bruce, and Andrei Buin, `` Numerical methods for solving the problem of electromagnetic scattering by a finite thin conducting wire'', accepted for publication in IEEE. Trans. Antennas and Propag. [2] P. C. Waterman, ``Scattering, absorption and extinction by thin fibers,'' Accepted for publication in J. Opt. Soc. A.

  9. High-resolution ice thickness and bed topography of a land-terminating section of the Greenland Ice Sheet

    DEFF Research Database (Denmark)

    Lindbäck, K.; Pettersson, R.; Doyle, S. H.;

    2014-01-01

    . The covered area is one of the most studied regions of the Greenland Ice Sheet with studies of mass balance, dynamics, and supraglacial lakes, and our combined dataset can be valuable for detailed studies of ice sheet dynamics and hydrology. The compiled datasets of ground-based and airborne radar surveys......We present ice thickness and bed topography maps with high spatial resolution (250 to 500 m) of a and-terminating section of the Greenland Ice Sheet derived from combined ground-based and airborne radar surveys. The data have a total area of ~12000 km2 and cover the whole ablation area...... of the outlet glaciers of Isunnguata Sermia, Russell, Leverett, Ørkendalen and Isorlersuup up to the long-term mass balance equilibrium line altitude at ~1600 m above sea level. The bed topography shows highly variable subglacial trough systems, and the trough of the Isunnguata Sermia Glacier is over...

  10. High resolution ice thickness, bed topography, and roughness of a land terminating section of the western Greenland Ice Sheet

    DEFF Research Database (Denmark)

    Lindback, K.; Pettersson, R.; Doyle, S. H.

    the spectral roughness. We see a strong correlation of low roughness values with the ice flow direction; this makes it important to assess the direction of the radar profiles in relation to the flow direction when calculating effective subglacial roughness for an area. Low roughness values and high surface......We present ice thickness and bed topography maps with high spatial resolution (250-500 m) of a large land terminating section of the western Greenland Ice Sheet. The maps cover the Isunnguata Sermia, Russell, and Leverett outlet glaciers and their catchment areas up to an elevation of ~1,700 m...... above sea level. The bed topography shows an intricate subglacial trough system, resembling the landscape in the proglacial area. We also calculate the hydraulic potential to get a proxy of the subglacial routing of water in the area. To analyse the geomorphological conditions of the bed, we calculated...

  11. Assessment of experimental d-PIGE γ-ray production cross sections for 12C, 14N and 16O and comparison with absolute thick target yields

    Science.gov (United States)

    Csedreki, L.; Halász, Z.; Kiss, Á. Z.

    2016-08-01

    Measured differential cross sections for deuteron induced γ-ray emission from the reactions 12C(d,pγ)13C, (Eγ = 3089 keV), 14N(d,pγ)15N (Eγ = 8310 keV) and 16O(d,pγ)17O (Eγ = 871 keV) available in the literature were assessed. In order to cross check the assessed γ-ray production cross section data, thick target γ-yields calculated from the differential cross sections were compared with available measured thick target yields. Recommended differential cross section data for each reaction were deduced for particle induced γ-ray emission (PIGE) applications.

  12. Research on Forging Die Design Ontology

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wenlei; FAN Yushun

    2006-01-01

    Forging die design is heavily dependent on engineers' experiences. But traditional AI technologies can barely provide a standard knowledge representation style for knowledge transferring. This paper introduces ontology into forging die design. 3-layer forging die design ontology is built, which includes Meta-ontology, Domain-ontology and Bottom ontology. Further, by conceptualization, the concepts and their relations are formally addressed by primitives such as Term, Relation and Function etc, which are explicitly expressed by concept tree. Bottom ontology uses Knowledge Item and Prototype to represent and capture general knowledge for knowledge reuse and share. Forging die design ontology building approach is discussed for standard knowledge representation, knowledge mine and knowledge driven CAD design etc. And OWL language is employed for integration among different domain ontologies integration. Finally a locomotive forging die KBE system is presented to demonstrate this approach.

  13. Effect of Hot Forging on Microstructural Evolution and Impact Toughness in Ultra-high Carbon Low Alloy Steel

    Science.gov (United States)

    Kim, J. B.; Kim, J. H.; Kang, C. Y.

    2016-12-01

    The effect of a hot forging ratio on the microstructural variation and tensile properties of ultra-high carbon low alloy steel was investigated. Scanning electron microscopic analyses depict that with an increase in the hot forging ratio, the thickness of the network and acicular proeutectoid cementite decreased. Moreover, the lamella spacing and thickness of the eutectoid cementite decreased and broke up into particle shapes, which then became spheroidized as the hot forging ratio increased. Furthermore, when the forging ratio exceeded 65%, the network and acicular shape of the as-cast state disappeared. By increasing the hot forging ratio, the tensile strength and elongation remained below 50%, but they increased rapidly with an increase in the forging ratio. Strength and elongation were not affected by the thickness of the proeutectoid and eutectoid cementites, but were greatly affected by the shape of the proeutectoid cementite. Due to the decrease in the austenite grain size, as well as the spheroidization of the cementite, the tensile strength and elongation sharply increased.

  14. Mechanics and forming theory of liquid metal forging

    Institute of Scientific and Technical Information of China (English)

    罗守靖; 姜巨福; 王迎; 藤东东

    2003-01-01

    On the basis of steel liquid forging and aluminium alloy liquid forging, liquid metal forging was investigated, such as the assembly model, metal plastic flowing, the force-displacement curves, the harmonious equation, calculation of value of altitude deformation and determination of specific pressure of liquid metal forging. On the basis of the theory of metal plastic forming and the characteristics of liquid metal forging, the achievements on the mechanics and forming theory of liquid metal forging were given out by combining the theory and experiments systematically, and an important preparation for establishing liquid metal forging theory was suggested.

  15. International cooperation in cold forging technology

    DEFF Research Database (Denmark)

    Bay, Niels; Lange, K

    1992-01-01

    of the ICFG are personally elected by the Plenary as experts within the field, often representing national groups within cold forging. The main work within the ICFG is carried out in its subgroups which are established by the Plenary to collect, compile and evaluate data and eventually also produce data......International cooperation in the field of cold forging technology started in 1961 by formation of the OECD Group of Experts on Metal Forming. In 1967 this group was transformed into the International Cold Forging Group, ICFG, an independent body which has now been operative for 25 years. Members...

  16. Processing and Characterization of Sub-delta Solvus Forged Hemispherical Forgings of Inconel 718

    Science.gov (United States)

    Chenna Krishna, S.; Rao, G. Sudarasana; Singh, Satish Kumar; Narayana Murty, S. V. S.; Venkatanarayana, G.; Jha, Abhay K.; Pant, Bhanu; Venkitakrishnan, P. V.

    2016-12-01

    In this paper, microstructure and mechanical properties of 200 mm diameter Inconel 718 hemispherical domes processed at 1025 °C through closed die hammer forging have been investigated. Microstructure and mechanical properties of the forgings in radial and tangential directions were characterized using optical microscopy, scanning electron microscopy, impact testing, and tensile testing. Grain size of the forgings at three different locations was fine with an average grain size of ASTM No. 8-9. The typical tensile properties of the forgings in solution-treated and aged condition were ultimate tensile strength-1450 MPa, yield strength-1240 MPa, and ductility-25%. The fine grain size achieved in forgings has been attributed to delta phase present at grain boundaries which pinned the grains during forging and prevented grain coarsening.

  17. Carotid intima-media thickness and apolipoproteins in patients of ischemic stroke in a rural hospital setting in central India: A cross-sectional study

    OpenAIRE

    Jyoti Jain; Tejal Lathia; Om Prakash Gupta; Vishakha Jain

    2012-01-01

    Context: Carotid intima-media thickness (CIMT) and apolipoproteins have been found as a risk factor for ischemic stroke . Objective: The objective was to study the carotid intima-media thickness, apolipoproteins, and their relation in patients of ischemic stroke in central rural India. Settings and Design: A cross-sectional study was performed in a rural hospital in central India. Materials and Methods: In all patients of ischemic stroke proven by computerized tomography (CT), CIMT, apolipopr...

  18. Forging of FeAl intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Flores, O.; Juarez, J.; Campillo, B.; Martinez, L. [UNAM, Cuernavaca (Mexico). Lab. de Cuernavaca; Schneibel, J.H. [Oak Ridge National Lab., TN (United States)

    1994-09-01

    Much activity has been concentrated on the development of intermetallic compounds with the aim of improving tensile ductility, fracture toughness and high notch sensitivity in order to develop an attractive combination of properties for high and low temperature applications. This paper reports experience in processing and forging of FeAl intermetallic of B2 type. During the experiments two different temperatures were employed, and the specimens were forged after annealing in air, 10{sup {minus}2} torr vacuum and argon. From the results it was learned that annealing FeAl in argon atmosphere prior to forging resulted in better deformation behavior than for the other two environments. For the higher forging temperature used in the experiments (700C), the as-cast microstructure becomes partially recrystallized.

  19. Mechanical Testing Development for Reservoir Forgings

    Energy Technology Data Exchange (ETDEWEB)

    Wenski, E.G.

    2000-05-22

    The goal of this project was to determine the machining techniques and testing capabilities required for mechanical property evaluation of commercially procured reservoir forgings. Due to the small size of these specific forgings, specialized methods are required to adequately machine and test these sub-miniature samples in accordance with the requirements of ASTM-E8 and ASTM-E9. At the time of project initiation, no capability existed at Federal Manufacturing & Technologies (FM&T) to verify the physical properties of these reservoirs as required on the drawing specifications. The project determined the sample definitions, machining processes, and testing procedures to verify the physical properties of the reservoir forgings; specifically, tensile strength, yield strength, reduction of area, and elongation. In addition, a compression test method was also developed to minimize sample preparation time and provide a more easily machined test sample while maintaining the physical validation of the forging.

  20. Contributions towards a monograph of Phoma (Coelomycetes) — VII. Section Sclerophomella: Taxa with thick-walled pseudoparenchymatous pycnidia

    NARCIS (Netherlands)

    Boerema, G.H.; Gruyter, de J.

    1998-01-01

    This paper deals with ten species of Phoma, characterized by thick-walled pseudoparenchymatous pycnidia. They superficially resemble the thick-walled pycnidial phenotype in species of Phoma sect. Plenodomus, but scleroplectenchyma is lacking and teleomorphs belong to Didymella, not Leptosphaeria. Ke

  1. Relation between intima-media thickness and bone mineral density in postmenopausal women: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Daniela Fodor

    Full Text Available CONTEXT AND OBJECTIVES: Controversy exists regarding the relationship between atherosclerosis and osteoporosis. The aim of this study was to determine the relationship between intima-media thickness (IMT of the common carotid artery (CCA, presence of calcified atherosclerotic plaques and bone mineral density (BMD evaluated by dual energy X-ray absorptiometry (DXA, in postmenopausal women. DESIGN AND SETTING: Cross-sectional study at Second Internal Medicine Clinic, Cluj-Napoca, Romania. METHODS: We studied the IMT (left and right CCA and mean IMT and T-score (lumbar spine L2-L4, femoral neck and total hip in 100 postmenopausal women (mean age 64.5 years. The presence of calcified atherosclerotic plaque and osteoporotic vertebral fractures was also noted. RESULTS: IMT in the left and right CCA and mean IMT were significantly associated with T-score measured for the lumbar spine L2-L4, femoral neck and total hip, with lower T-score, in the osteoporotic group than in the normal and osteopenic groups (P < 0.05. IMT had a significantly negative correlation with the lumbar spine T-score and femoral neck T-score; and mean IMT with lowest T-score. Mean IMT (P < 0.001, high blood pressure (P = 0.005 and osteoporotic vertebral fractures (P = 0.048 showed statistical significance regarding the likelihood of developing atherosclerotic plaque. CONCLUSIONS: In women referred for routine osteoporosis screening, the relationship between CCA, atherosclerosis and osteoporosis can be demonstrated using either cortical or trabecular BMD. Vertebral fractures may be considered to be a likelihood factor for atherosclerotic plaque development.

  2. Influence of the Constitutive Flow Law in FEM Simulation of the Radial Forging Process

    Directory of Open Access Journals (Sweden)

    Olivier Pantalé

    2013-01-01

    Full Text Available Radial forging is a widely used forming process for manufacturing hollow products in transport industry. As the deformation of the workpiece, during the process, is a consequence of a large number of high-speed strokes, the Johnson-Cook constitutive law (taking into account the strain rate seems to be well adapted for representing the material behavior even if the process is performed under cold conditions. But numerous contributions concerning radial forging analysis, in the literature, are based on a simple elastic-plastic formulation. As far as we know, this assumption has yet not been validated for the radial forging process. Because of the importance of the flow law in the effectiveness of the model, our purpose in this paper is to analyze the influence of the use of an elastic-viscoplastic formulation instead of an elastic-plastic one for modeling the cold radial forging process. In this paper we have selected two different laws for the simulations: the Johnson-Cook and the Ludwik ones, and we have compared the results in terms of forging force, product's thickness, strains, stresses, and CPU time. For the presented study we use an AISI 4140 steel, and we denote a fairly good agreement between the results obtained using both laws.

  3. Metallurgical modelling of superalloy disc isothermal forgings

    Science.gov (United States)

    Evans, R. W.

    1988-08-01

    The metallurgical structure of superalloy aeroengine disc forgings is a complex function of the forging operation parameters and the post forging heat treatment. It is often desirable to obtain certain specific structures in parts of the disc which are, for instance, resistant to crack propagation and this has traditionally been accomplished by means of a series of production trials. This expensive and time consuming procedure can be considerably shortened if the development of microstructure during the forging can be accurately modelled by a suitable computer code. Described here is such a model and its use in the design of isothermal forged components. The model discribed is a fully thermally coupled viscoplasticity finite element algorithm. It treats nodal velocities as the basic unknowns and both the mesh geometry and the various metallurgical structural terms are updated by a single step Euler scheme. Facilities are available for ensuring that surface nodes follow die shapes after impingement, that flow is incompressible and that suitable surface friction forces are applied. Throughout the whole forging process (which may involve the re-meshing of severely distorted elements), the metallurgical history of elements is retained so that the effects of subsequent heat treatments can be assessed.

  4. Research on forging method of marine long-shaft heaving forging%船用长轴类大锻件锻造工艺方法研究

    Institute of Scientific and Technical Information of China (English)

    夏琴香; 向可; 赵学智; 李一振

    2013-01-01

    船用长轴类大锻件是船舶动力装置的重要组成部分,其质量好坏直接影响船舶的推进特性和正常航行.本文以某船用中间轴为研究对象,对普通平砧锻造法、FM锻造法和上下砧不等宽锻造方法下的压方过程进行了数值模拟,应用数值模拟软件Deform-3D建立了相应的有限元模型,对坯料温度场、应力分布、锻造力和锻造效率进行了分析.结果表明:采用平砧锻造时,锻件的锻造效率最高,所需锻造力小,且表面温度下降最慢;采用FM法锻造时能获得较理想的压应力分布状态.%As the most important components of marine power installation, the quality of the long-axis heavy forgings has a direct influence on the hydrodynamic characteristics and normal voyage of marine. The squaring process of the marine intermediate shaft forged by flat anvil, FM method and the unequal flat anvil was simulated. The finite element model was established based on numerical simulation software Deform-3D, and the temperature field, stress distribution, forging force and forging efficiency were analyzed. The results show that comparing with the FM method and unequal flat anvil forging, when forging by flat anvil, the forming efficiency is the highest, the forging force is the smallest and the deceasing speed of the surface temperature of forging billet is the slowest; when forging by FM method, the ideal compressive stress distribution state can be obtained along the billet cross section.

  5. Intelligent Control of a Novel Hydraulic Forging Manipulator

    Directory of Open Access Journals (Sweden)

    J. Wang

    2011-01-01

    Full Text Available The increased demand for large-size forgings has led to developments and innovations of heavy-duty forging manipulators. Besides the huge carrying capacity, some robot features such as force perception, delicacy and flexibility, forging manipulators should also possess. The aim of the work is to develop a heavy-duty forging manipulator with robot features by means of combination of methods in mechanical, hydraulic, and control field. In this paper, through kinematic analysis of a novel forging manipulator, control strategy of the manipulator is proposed considering the function and motion of forging manipulators. Hybrid pressure/position control of hydraulic actuators in forging manipulator is realized. The feasibility of the control method has been verified by the experiments on a real prototype of the novel hydraulic forging manipulator in our institute. The intelligent control of the forging manipulator is performed with programmable logic controller which is suitable for industrial applications.

  6. Microstructural and mechanical evolutions during the forging step of the COBAPRESS, a casting/forging process

    Science.gov (United States)

    Perrier, Frédéric; Desrayaud, Christophe; Bouvier, Véronique

    Aluminum casting/forging processes are used to produce parts for the automotive industry. In this study, we examined the influence of the forging step on the microstructure and the mechanical properties of an A356 aluminum alloy modified with strontium. Firstly, a design of samples which allows us to test mechanically the alloy before and after forging was created. A finite element analysis with the ABAQUS software predicts a maximum of strain in the core of the specimens. Observations with the EBSD technique confirm a more intense sub-structuration of the dendrite cells in this zone. Yield strength, ultimate tensile strength, elongation and fatigue lives were then improved for the casting/forging samples compared to the only cast specimens. The closure of the porosities and the improvement of the surface quality during the forging step enhance also the fatigue resistance of the samples.

  7. Monte Carlo electron-trajectory simulations in bright-field and dark-field STEM: Implications for tomography of thick biological sections

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, A.A.; Hohmann-Marriott, M.F.; Zhang, G. [Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bldg. 13, Rm. 3N17, 13 South Drive, Bethesda, MD 20892-5766 (United States); Leapman, R.D. [Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bldg. 13, Rm. 3N17, 13 South Drive, Bethesda, MD 20892-5766 (United States)], E-mail: leapmanr@mail.nih.gov

    2009-02-15

    A Monte Carlo electron-trajectory calculation has been implemented to assess the optimal detector configuration for scanning transmission electron microscopy (STEM) tomography of thick biological sections. By modeling specimens containing 2 and 3 at% osmium in a carbon matrix, it was found that for 1-{mu}m-thick samples the bright-field (BF) and annular dark-field (ADF) signals give similar contrast and signal-to-noise ratio provided the ADF inner angle and BF outer angle are chosen optimally. Spatial resolution in STEM imaging of thick sections is compromised by multiple elastic scattering which results in a spread of scattering angles and thus a spread in lateral distances of the electrons leaving the bottom surface. However, the simulations reveal that a large fraction of these multiply scattered electrons are excluded from the BF detector, which results in higher spatial resolution in BF than in high-angle ADF images for objects situated towards the bottom of the sample. The calculations imply that STEM electron tomography of thick sections should be performed using a BF rather than an ADF detector. This advantage was verified by recording simultaneous BF and high-angle ADF STEM tomographic tilt series from a stained 600-nm-thick section of C. elegans. It was found that loss of spatial resolution occurred markedly at the bottom surface of the specimen in the ADF STEM but significantly less in the BF STEM tomographic reconstruction. Our results indicate that it might be feasible to use BF STEM tomography to determine the 3D structure of whole eukaryotic microorganisms prepared by freeze-substitution, embedding, and sectioning.

  8. A Knowledge base model for complex forging die machining

    OpenAIRE

    Mawussi, Kwamiwi; Tapie, Laurent

    2011-01-01

    International audience; Recent evolutions on forging process induce more complex shape on forging die. These evolutions, combined with High Speed Machining (HSM) process of forging die lead to important increase in time for machining preparation. In this context, an original approach for generating machining process based on machining knowledge is proposed in this paper. The core of this approach is to decompose a CAD model of complex forging die in geometric features. Technological data and ...

  9. 论最小锻比%Statement of the Minimum Forging Ratio

    Institute of Scientific and Technical Information of China (English)

    任猛; 钱莉丽; 杜锦; 江盛龙

    2015-01-01

    The forging ratio is just a macro indicator and only shows the shape change of the forging cross section. The determinant parameters such as the anvil width ratio and reduction which influence on the inner deformation will be controlled and the acceptable products will be obtained with minimum forging ratio.%锻比作为一个宏观指标,只代表锻件所经历的截面形状变化。合理控制砧宽比、压下量等对内部变形起决定性作用的参数,可以在小锻比条件下生产合格产品。

  10. Near-Net Forging Technology Demonstration Program

    Science.gov (United States)

    Hall, I. Keith

    1996-01-01

    Significant advantages in specific mechanical properties, when compared to conventional aluminum (Al) alloys, make aluminum-lithium (Al-Li) alloys attractive candidate materials for use in cryogenic propellant tanks and dry bay structures. However, the cost of Al-Li alloys is typically five times that of 2219 aluminum. If conventional fabrication processes are employed to fabricate launch vehicle structure, the material costs will restrict their utilization. In order to fully exploit the potential cost and performance benefits of Al-Li alloys, it is necessary that near-net manufacturing methods be developed to off-set or reduce raw material costs. Near-net forging is an advanced manufacturing method that uses elevated temperature metal movement (forging) to fabricate a single piece, near-net shape, structure. This process is termed 'near-net' because only a minimal amount of post-forge machining is required. The near-net forging process was developed to reduce the material scrap rate (buy-to-fly ratio) and fabrication costs associated with conventional manufacturing methods. The goal for the near-net forging process, when mature, is to achieve an overall cost reduction of approximately 50 percent compared with conventional manufacturing options for producing structures fabricated from Al-Li alloys. This NASA Marshall Space Flight Center (MSFC) sponsored program has been a part of a unique government / industry partnership, coordinated to develop and demonstrate near-net forging technology. The objective of this program was to demonstrate scale-up of the near-net forging process. This objective was successfully achieved by fabricating four integrally stiffened, 170- inch diameter by 20-inch tall, Al-Li alloy 2195, Y-ring adapters. Initially, two 2195 Al-Li ingots were converted and back extruded to produce four cylindrical blockers. Conventional ring rolling of the blockers was performed to produce ring preforms, which were then contour ring rolled to produce

  11. Dynamic Recrystallization Behavior of Microalloyed Forged Steel

    Institute of Scientific and Technical Information of China (English)

    WANG Jin; CHEN Jun; ZHAO Zhen; RUAN Xue-yu

    2008-01-01

    The dynamic recrystallization behavior of microalloyed forged steel was investigated with a compression test in the temperature range of 1 223--1 473 K and a strain rate of 0. 01--5 s-1. Activation energy was calculated to be 305. 9 kJ/mol by regression analysis. Modeling equations were developed to represent the dynamic reerystalliza-tion volume fraction and grain size. Parameters of the modeling equations were determined as a function of the Zener-Hollomon parameter. The developed modeling equation will be combined with finite element modeling to prediet microstructural change during the hot forging processing.

  12. Rotational Augmentation on a 2.3 MW Rotor Blade with Thick Flatback Airfoil Cross-Sections: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Schreck, S.; Fingersh, L.; Siegel, K.; Singh, M.; Medina, P.

    2013-01-01

    Rotational augmentation was analyzed for a 2.3 MW wind turbine, which was equipped with thick flatback airfoils at inboard radial locations and extensively instrumented for acquisition of time varying surface pressures. Mean aerodynamic force and surface pressure data were extracted from an extensive field test database, subject to stringent criteria for wind inflow and turbine operating conditions. Analyses of these data showed pronounced amplification of aerodynamic forces and significant enhancements to surface pressures in response to rotational influences, relative to two-dimensional, stationary conditions. Rotational augmentation occurrence and intensity in the current effort was found to be consistent with that observed in previous research. Notably, elevated airfoil thickness and flatback design did not impede rotational augmentation.

  13. Die forging of the alloys Az80 and Zk60

    NARCIS (Netherlands)

    Kurz, G.; Clauw, B.; Sillekens, W.H.; Letzig, D.

    2009-01-01

    Overall goal of the MagForge project is to provide tailored and cost-effective technologies for the industrial manufacturing of magnesium forged components. Scientific and technological aspects are new alloys/feedstock materials with improved performance, forging process modeling and design tools wi

  14. The Effect of Blade-Section Thickness Ratio on the Aerodynamic Characteristics of Related Full-Scale Propellers at Mach Numbers up to 0.65

    Science.gov (United States)

    Maynard, Julian D; Steinberg, Seymour

    1953-01-01

    The results of an investigation of two 10-foot-diameter, two-blade NACA propellers are presented for a range of blade angles from 20 degrees to 55 degrees at airspeeds up to 500 miles per hour. These results are compared with those from previous investigations of five related NACA propellers in order to evaluate the effects of blade-section thickness ratios on propeller aerodynamic characteristics.

  15. A method for combining RNAscope in situ hybridization with immunohistochemistry in thick free-floating brain sections and primary neuronal cultures.

    Science.gov (United States)

    Grabinski, Tessa M; Kneynsberg, Andrew; Manfredsson, Fredric P; Kanaan, Nicholas M

    2015-01-01

    In situ hybridization (ISH) is an extremely useful tool for localizing gene expression and changes in expression to specific cell populations in tissue samples across numerous research fields. Typically, a research group will put forth significant effort to design, generate, validate and then utilize in situ probes in thin or ultrathin paraffin embedded tissue sections. While combining ISH and IHC is an established technique, the combination of RNAscope ISH, a commercially available ISH assay with single transcript sensitivity, and IHC in thick free-floating tissue sections has not been described. Here, we provide a protocol that combines RNAscope ISH with IHC in thick free-floating tissue sections from the brain and allows simultaneous co-localization of genes and proteins in individual cells. This approach works well with a number of ISH probes (e.g. small proline-rich repeat 1a, βIII-tubulin, tau, and β-actin) and IHC antibody stains (e.g. tyrosine hydroxylase, βIII-tubulin, NeuN, and glial fibrillary acidic protein) in rat brain sections. In addition, we provide examples of combining ISH-IHC dual staining in primary neuron cultures and double-ISH labeling in thick free-floating tissue sections from the brain. Finally, we highlight the ability of RNAscope to detect ectopic DNA in neurons transduced with viral vectors. RNAscope ISH is a commercially available technology that utilizes a branched or "tree" in situ method to obtain ultrasensitive, single transcript detection. Immunohistochemistry is a tried and true method for identifying specific protein in cell populations. The combination of a sensitive and versatile oligonucleotide detection method with an established and versatile protein assay is a significant advancement in studies using free-floating tissue sections.

  16. Forging Collaborative Partnerships: The Waterloo Neighborhood Project.

    Science.gov (United States)

    Gruenewald, Anne

    The Forging Collaborative Partnerships Project in Waterloo, Iowa is a collaborative venture to assist voluntary agencies in developing tools and strategies to strengthen collaborative relationships among public and nonprofit child welfare agencies and other key stakeholders as they adopt a family-focused philosophy. This monograph details how the…

  17. Modelling and Testing of Friction in Forging

    DEFF Research Database (Denmark)

    Bay, Niels

    2007-01-01

    Knowledge about friction is still limited in forging. The theoretical models applied presently for process analysis are not satisfactory compared to the advanced and detailed studies possible to carry out by plastic FEM analyses and more refined models have to be based on experimental testing...

  18. 29 CFR 1910.218 - Forging machines.

    Science.gov (United States)

    2010-07-01

    ... a man to reach the full length of the die without placing his hand or arm between the dies. (vii... specifications or dimensions shown in Table O-11. (2) Hydraulic forging presses. When dies are being changed or maintenance is being performed on the press, the following shall be accomplished: (i) The hydraulic pumps and...

  19. Carotid intima-media thickness and apolipoproteins in patients of ischemic stroke in a rural hospital setting in central India: A cross-sectional study.

    Science.gov (United States)

    Jain, Jyoti; Lathia, Tejal; Gupta, Om Prakash; Jain, Vishakha

    2012-01-01

    Carotid intima-media thickness (CIMT) and apolipoproteins have been found as a risk factor for ischemic stroke The objective was to study the carotid intima-media thickness, apolipoproteins, and their relation in patients of ischemic stroke in central rural India. A cross-sectional study was performed in a rural hospital in central India. In all patients of ischemic stroke proven by computerized tomography (CT), CIMT, apolipoprotein A-I (ApoA-I), and apolipoprotein B(ApoB) were measured. We used Student's t-test to compare means, a chi-square test to compare proportions, and a Mann-Whitney test to compare medians. A P value 90 mg/dl with CIMT > 0.7 mm was statistically significant with P 0.7 mm was also statistically significant.

  20. Carotid intima-media thickness and apolipoproteins in patients of ischemic stroke in a rural hospital setting- in central India: A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Jyoti Jain

    2012-01-01

    Full Text Available Context: Carotid intima-media thickness (CIMT and apolipoproteins have been found as a risk factor for ischemic stroke . Objective: The objective was to study the carotid intima-media thickness, apolipoproteins, and their relation in patients of ischemic stroke in central rural India. Settings and Design: A cross-sectional study was performed in a rural hospital in central India. Materials and Methods: In all patients of ischemic stroke proven by computerized tomography (CT, CIMT, apolipoprotein A-I (ApoA-I, and apolipoprotein B(ApoB were measured. Statistical Analysis Used: We used Student′s t-test to compare means, a chi-square test to compare proportions, and a Mann-Whitney test to compare medians. A P value 90 mg/dl with CIMT > 0.7 mm was statistically significant with P 0.7 mm was also statistically significant.

  1. 2014 Accomplishments-Tritium aging studies on stainless steel: Fracture toughness properties of forged stainless steels-Effect of hydrogen, forging strain rate, and forging temperature

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-02-01

    Forged stainless steels are used as the materials of construction for tritium reservoirs. During service, tritium diffuses into the reservoir walls and radioactively decays to helium-3. Tritium and decay helium cause a higher propensity for cracking which could lead to a tritium leak or delayed failure of a tritium reservoir. The factors that affect the tendency for crack formation and propagation include: Environment; steel type and microstructure; and, vessel configuration (geometry, pressure, residual stress). Fracture toughness properties are needed for evaluating the long-term effects of tritium on their structural properties. Until now, these effects have been characterized by measuring the effects of tritium on the tensile and fracture toughness properties of specimens fabricated from experimental forgings in the form of forward-extruded cylinders. A key result of those studies is that the long-term cracking resistance of stainless steels in tritium service depends greatly on the interaction between decay helium and the steels’ forged microstructure. New experimental research programs are underway and are designed to measure tritium and decay helium effects on the cracking properties of stainless steels using actual tritium reservoir forgings instead of the experimental forgings of past programs. The properties measured should be more representative of actual reservoir properties because the microstructure of the specimens tested will be more like that of the tritium reservoirs. The programs are designed to measure the effects of key forging variables on tritium compatibility and include three stainless steels, multiple yield strengths, and four different forging processes. The effects on fracture toughness of hydrogen and crack orientation were measured for type 316L forgings. In addition, hydrogen effects on toughness were measured for Type 304L block forgings having two different yield strengths. Finally, fracture toughness properties of type 304L

  2. Fatigue experience from tests carried out with forged beam and frame structures in the development of the Saab aircraft Viggen

    Science.gov (United States)

    Larsson, S. E.

    1972-01-01

    A part of the lower side of the main wing at the joint of the main spar with the fuselage frame was investigated. This wing beam area was simulated by a test specimen consisting of a spar boom of AZ 74 forging (7075 aluminum alloy modified with 0.3 percent Ag) and a portion of a honeycomb sandwich panel attached to the boom flange with steel bolts. The cross section was reduced to half scale. However, the flange thickness, the panel height, and the bolt size were full scale. Further, left and right portions of the fuselage frame intended to carry over the bending moment of the main wing were tested. Each of these frame halves consisted of a forward and a rear forging (7079 aluminum alloy, overaged) connected by an outer and inner skin (Alclad 7075) creating a box beam. These test specimens were full scale and were constructed principally of ordinary aircraft components. The test load spectrum was common to both types of specimens with regard to percentage levels. It consisted of maneuver and gust loads, touchdown loads, and loads due to ground roughness. A load history of 200 hours of flight with 15,000 load cycles was punched on a tape. The loads were randomized in groups according to the flight-by-flight principle. The highest positive load level was 90 percent of limit load and the largest negative load was -27 percent. A total of 20 load levels were used. Both types of specimens were provided with strain gages and had a nominal stress of about 300 MN/sq m in some local areas. As a result of the tests, steps were taken to reduce the risk of fatigue damage in aircraft. Thus stress levels were lowered, radii were increased, and demands on surface finish were sharpened.

  3. Modelling of defects in ingot forging

    DEFF Research Database (Denmark)

    Christiansen, Peter

    experimentally by utilizing downscaled lead model ingots (billets) being compressed by a tool with different lower die angles. Centreline defects, occurring due to the ingot casting processes, are modelled by drilling holes through the centreline of the cast billets. The experiments showed a marked influence...... are in closer agreement with the general understanding of the ingot forging process. Therefore porous metal plasticity should not be used solely when evaluating the soundness of the final, forged ingot based on FEM simulations. Based on an analysis of forming fracture limit diagrams combined with uncoupled...... ductile damage criteria, it is found that the normalized Cockcroft & Latham criterion is most suited for modelling damage in bulk metal forming, if the forming fracture limit diagram can be described by a straight line having a slope of -1/2. A damage criterion independent of slope is presented. Often...

  4. Decomposition of forging dies for machining planning

    CERN Document Server

    Tapie, Laurent; Anselmetti, Bernard

    2009-01-01

    This paper will provide a method to decompose forging dies for machining planning in the case of high speed machining finishing operations. This method lies on a machining feature approach model presented in the following paper. The two main decomposition phases, called Basic Machining Features Extraction and Process Planning Generation, are presented. These two decomposition phases integrates machining resources models and expert machining knowledge to provide an outstanding process planning.

  5. Decomposition of forging dies for machining planning

    OpenAIRE

    Tapie, Laurent; Mawussi, Kwamiwi; Anselmetti, Bernard

    2009-01-01

    International audience; This paper will provide a method to decompose forging dies for machining planning in the case of high speed machining finishing operations. This method lies on a machining feature approach model presented in the following paper. The two main decomposition phases, called Basic Machining Features Extraction and Process Planning Generation, are presented. These two decomposition phases integrates machining resources models and expert machining knowledge to provide an outs...

  6. Improvements in the process of boss bar upset forging into a horizontal forging machine with the aim of joint knuckle forging quality improvement

    Science.gov (United States)

    Pankratov, D. L.; Nizamov, R. S.; Kharisov, I. Zh

    2016-06-01

    A new technique for tapered composing transition shaping has been put forward in the process of upset forging with the use of an experimental tool. The results of the upset forging process with the use of a new composing transition has been computer simulated.

  7. Ventrogluteal versus dorsogluteal site selection: A cross-sectional study of muscle and subcutaneous fat thicknesses and an algorithm incorporating demographic and anthropometric data to predict injection outcome.

    Science.gov (United States)

    Larkin, Theresa A; Ashcroft, Elfriede; Elgellaie, Asmahan; Hickey, Blake A

    2017-06-01

    The dorsogluteal and ventrogluteal intramuscular injection sites both have their use in clinical practice; however, it has not been established in whom one or the other should be preferentially targeted or avoided. There is a need for an evidence-based approach towards site selection for a successful intramuscular injection outcome and to avoid unwanted injection outcomes of inadvertent subcutaneous injection or bone contact. Injection outcome is dependent on injection site subcutaneous fat thickness and muscle thickness; these are likely influenced by gender and anthropometry. To determine whether subcutaneous fat, muscle, and total tissue thicknesses differ between the dorsogluteal and ventrogluteal sites, and whether theoretical injection outcome (intramuscular, subcutaneous, or bone contact) can be predicted by demographic and anthropometric data and described by an algorithm. Cross-sectional study design. University in Australia. 145 volunteers (57% female) of at least 18 years of age recruited through the university community. Anthropometric data was collected and subcutaneous fat and muscle thicknesses were quantified by ultrasonography. Anthropometric differences between theoretical injection outcome groups (bone contact versus intramuscular versus subcutaneous at the ventrogluteal and dorsogluteal sites) was determined for each gender (ANOVA). Multiple regression analysis was conducted to determine the influence of demographic and anthropometric data on theoretical intramuscular injection outcome. An algorithm to guide site selection was developed for each gender, based on the anthropometric measures that best discriminated between injection outcomes. Subcutaneous fat, muscle and total tissue were significantly thicker at the dorsogluteal site than the ventrogluteal site, and subcutaneous fat was significantly thicker in females than males at both sites (all psubcutaneous fat thickness at both sites; male gender was a significant predictor of dorsogluteal

  8. Intra-rater and Inter-rater Reliability of Rehabilitative Ultrasound Imaging of Multifidus Muscle Thickness, Cross Section Area and Bladder Wall Displacement in Multiparous Women

    Directory of Open Access Journals (Sweden)

    Zahra Teymuri

    2016-03-01

    Full Text Available Background. Pregnancy related changes can affect the role of multifidus (MF and pelvic floor muscles (PFM in the spinal stability and load transfer mechanism. Rehabilitative ultrasound imaging (RUSI is a powerful tool that provides unavailable information about the myofascial system. Objective. This study aimed to determine intra-rater and inter-rater reliability of ultrasound imaging in the measurement of MF thickness, cross section area (CSA and bladder wall displacement as a reflection of PFM action in multiparous healthy women. Design.A single-group repeated measures reliability study was conducted. Methods. Ten healthy multiparous women (mean age=35.36 SD=7.71 participated in this study. Bladder wall displacement in the transverse plan through trans-abdominal (TA approach, MF muscle thickness at rest and during contralateral arm lift (CAL and MF muscle CSA were obtained by using RUSI. Infraclass correlation coefficient (ICC with 95% confidence interval (CI, standard error of measurement (SEM and minimal detectable change (MDC were calculated for all variables. Results: ICC values with 95% CI showed that bladder wall displacement has high intra-rater (ICC: 0.91-0.99 and high inter-rater reliability (ICC: 0.93-0.96, MF muscle thickness has good to high intra-rater (ICC: ranged from 0.85 to 0.98 and good to high inter-rater reliability (ICC ranged from0.73 to 0.98 and MF muscle CSA has good to high intra-rater (ICC: 0.78-0.86 and fair inter-rater reliability (ICC: 0.54-0.61. SEMs ranged from 0.69 to 3.98 mm and MDCs ranged from 1.92 to 11.03 mm. Limitation.The number of delivery was not equal between subjects. Conclusions. RUSI is a reliable method in measurement of bladder wall displacement, MF muscle thickness and CSA in multiparous women.

  9. A Knowledge base model for complex forging die machining

    CERN Document Server

    Mawussi, Kwamiwi; 10.1016/j.cie.2011.02.016

    2011-01-01

    Recent evolutions on forging process induce more complex shape on forging die. These evolutions, combined with High Speed Machining (HSM) process of forging die lead to important increase in time for machining preparation. In this context, an original approach for generating machining process based on machining knowledge is proposed in this paper. The core of this approach is to decompose a CAD model of complex forging die in geometric features. Technological data and topological relations are aggregated to a geometric feature in order to create machining features. Technological data, such as material, surface roughness and form tolerance are defined during forging process and dies design. These data are used to choose cutting tools and machining strategies. Topological relations define relative positions between the surfaces of the die CAD model. After machining features identification cutting tools and machining strategies currently used in HSM of forging die, are associated to them in order to generate mac...

  10. Influence of Forging on Static Pricing Scheme for Priority Services

    Institute of Scientific and Technical Information of China (English)

    LIU Ji-cheng; SHI Bing-xin; YANG Xue-nan; LI Bo

    2005-01-01

    The influence of ISP's ( internet service provider) forging on static pricing scheme for priority services is analyzed. If ISP is honest, besides the price, after users enter the network market, it can't affect the market; if it forges, it can change its utility. The economical analysis proves that forging is possible, when ISP gains more than its loss, ISP will take the action. In response to forging, users may adapt their traffic allocation vectors to maximize their net benefit. If users will submit more traffic or in higher priority service class, ISP gains from the behavior, if users will submit less traffic or even exits the market, ISP 's utility decrease. The market is completely different from before, forging changes the market. Several examples are presented to illustrate the results. At the same time, how the utility function and the willingness to pay affect forging is discussed.

  11. Enhancement of Aluminum Alloy Forgings through Rapid Billet Heating

    Energy Technology Data Exchange (ETDEWEB)

    Kervick, R.; Blue, C. A.; Kadolkar, P. B.; Ando, T.; Lu, H.; Nakazawa, K.; Mayer, H.; Mochnal, G.

    2006-06-01

    Forging is a manufacturing process in which metal is pressed, pounded or squeezed under great pressure and, often, under high strain rates into high-strength parts known as forgings. The process is typically performed hot by preheating the metal to a desired temperature before it is worked. The forging process can create parts that are stronger than those manufactured by any other metal working process. Forgings are almost always used where reliability and human safety are critical. Forgings are normally component parts contained inside assembled items such airplanes, automobiles, tractors, ships, oil drilling equipment, engines missiles, and all kinds of capital equipment Forgings are stronger than castings and surpass them in predictable strength properties, producing superior strength that is assured, part to part.

  12. An empirical model for friction in cold forging

    DEFF Research Database (Denmark)

    Bay, Niels; Eriksen, Morten; Tan, Xincai

    2002-01-01

    With a system of simulative tribology tests for cold forging the friction stress for aluminum, steel and stainless steel provided with typical lubricants for cold forging has been determined for varying normal pressure, surface expansion, sliding length and tool/work piece interface temperature...... of normal pressure and tool/work piece interface temperature. The model is verified by process testing measuring friction at varying reductions in cold forward rod extrusion. KEY WORDS: empirical friction model, cold forging, simulative friction tests....

  13. Numerical modelling of the forging process of rolls for rolling mills

    OpenAIRE

    Charles, J F; Castagne, S.; Zhang, Lihong; Habraken, Anne; Cescotto, Serge

    2000-01-01

    This article presents comparisons of forging processes between two flat tools, between two round tools, and at different forging temperatures. Simulation results help to recover and better understa,d long practice in the forging industry. Peer reviewed

  14. Effect of Forging Allowance Value on the Power Consumption of Machining Process

    Directory of Open Access Journals (Sweden)

    L. D. Mal'kova

    2015-01-01

    Full Text Available The paper aim is to develop and study possible energy-efficiency measures for machined forgings drawing on analysis of the impact of the allowance for machining and its scatter.The most sophisticated option to take into consideration the effect of the cut depth is the work-piece machining in which the forging allowance value results from the blank production.Research of power consumption was conducted for turning the cylindrical surface of 144 mm length and  1,5 33 0,5   diameter on forgings of the work-pieces "screw of steering control" made from steel 60PP. A radial dimension allowance at said cylindrical surface at six points of the five sections was sized to assess the allowance value dispersion. The size of the sample measurements at the control points was n = 600. Statistic processing has shown normal law of distribution and sample homogeneity.To analyze the results of experiments was calculated a range of allowances for this workpiece. Calculated minimum and maximum allowance per one side for rough lathing were, respectively, 0.905 mm and 1.905mm. It was found that 77% points under control lie in calculated range of allowance values. And there are no points out of the range on lesser side that proves a lack of rejects; but there are points out of the range on the bigger side, that will require additional costs for machining the specified surface, including the cost of electricity.There were three power consumption calculations based on factory- recommended duty: for processing the entire sample of forgings with an average allowance, for machining forgings allowances of which are within the recommended design range of allowance, and for processing the entire sample of forgings with a minimum value of allowance.It was found that elimination of allowance values which are outside the recommended range enables to reduce the power consumption, at least, by 6%, and the overall power consumption for processing the measured forgings

  15. European Community research on forging of magnesium alloys (MagForge): state of affairs

    NARCIS (Netherlands)

    Sillekens, W.H.; Chevaleyre, F.; Gantar, G.

    2009-01-01

    While the interest in wrought magnesium applications is growing, forging of magnesium alloys in Europe and beyond is still restricted to a few specialized companies that operate for niche markets. Technical matters that relate to this are underdeveloped mechanical properties of available feedstock m

  16. European Community research on forging of magnesium alloys (MagForge): state of affairs

    NARCIS (Netherlands)

    Sillekens, W.H.; Chevaleyre, F.; Gantar, G.

    2009-01-01

    While the interest in wrought magnesium applications is growing, forging of magnesium alloys in Europe and beyond is still restricted to a few specialized companies that operate for niche markets. Technical matters that relate to this are underdeveloped mechanical properties of available feedstock

  17. Examples on cold forged aluminium components in automotive industry

    DEFF Research Database (Denmark)

    Bay, Niels; Kolsgaard, A.

    2000-01-01

    The present paper describes the possibilites of applying cold forging for manufacturing of light weight components in aluminium. A short description of the basic cold forming processes forms the basis for describing the great variety in design of cold forged components. Examples are mainly taken ...

  18. Kinematics at the Main Mechanism of a Railbound Forging Manipulator

    Directory of Open Access Journals (Sweden)

    Florian Ion Tiberiu Petrescu

    2015-09-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Heavy payload forging manipulators are mainly characterized by large load output and large capacitive load input. The relationship between outputs and inputs will greatly influence the control and the reliability. Forging manipulators have become more prevalent in the industry today. They are used to manipulate objects to be forged. The most common forging manipulators are moving on a railway to have a greater precision and stability. They have been called the railbound forging manipulators. In this paper we analyze the general kinematics of the main mechanism from a such manipulator. Kinematic scheme shows a typical forging manipulator, with the basic motions in operation process: walking, motion of the tong and buffering. The lifting mechanism consists of several parts including linkages, hydraulic drives and motion pairs. The principle of type design from the viewpoints of the relationship between output characteristics and actuator inputs is discussed. An idea of establishing the incidence relationship between output characteristics and actuator inputs is proposed. These novel forging manipulators which satisfy certain functional requirements provide an effective help for the design of forging manipulators.

  19. Numerical Analysis on Rotary Forging Mechanism of a Flange

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A numerical simulation on the rotary forging process of a flange is conducted by three-dimensional rigid-plastic finite element method. The states of stress and strain rate in the workpiece are analyzed and the forging mechanism of the flange is revealed. Moreover, the influence of the die configuration on the material flow is also analyzed.

  20. Examples on cold forged aluminium components in automotive industry

    DEFF Research Database (Denmark)

    Bay, Niels; Kolsgaard, A.

    2000-01-01

    The present paper describes the possibilites of applying cold forging for manufacturing of light weight components in aluminium. A short description of the basic cold forming processes forms the basis for describing the great variety in design of cold forged components. Examples are mainly taken ...... from automotive industry but in a few cases also from other industrial sectors to show the possibilities....

  1. 31 CFR 370.40 - Can I be held accountable if my negligence contributes to a forged signature?

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Can I be held accountable if my negligence contributes to a forged signature? 370.40 Section 370.40 Money and Finance: Treasury Regulations... Submission of Transaction Requests Through the Bureau of the Public Debt § 370.40 Can I be held...

  2. Carotid intima-media thickness and apolipoproteins in patients of ischemic stroke in a rural hospital setting in central India: A cross-sectional study

    National Research Council Canada - National Science Library

    Jain, Jyoti; Lathia, Tejal; Gupta, Om Prakash; Jain, Vishakha

    2012-01-01

    Carotid intima-media thickness (CIMT) and apolipoproteins have been found as a risk factor for ischemic stroke The objective was to study the carotid intima-media thickness, apolipoproteins, and their relation in patients of ischemic...

  3. 冷弯厚壁矩形型钢管冷弯效应%Strain hardening of thick-walled cold formed steel rectangular hollow section

    Institute of Scientific and Technical Information of China (English)

    胡盛德; 李立新; 周家林

    2011-01-01

    针对断面规格为口200×300×9.2的冷弯厚壁矩形型钢管,进行了平板、弯角、相应母材和短柱试件的力学性能试验.结合冷弯生产工艺,分析了平板、弯角试件力学性能随冷弯道次的变化规律,并与相关厚壁型钢冷作硬化效应作了比较.运用国内外冷弯型钢设计规范和相关文献中的修正公式,对该厚壁冷弯方形型钢全截面强度进行了设计和对比分析.结果表明:国内薄壁和国外厚壁公式都不可直接用于本冷弯厚壁矩形型钢强度设计,国外公式更偏于危险;魏氏体组织是造成带焊缝板件强度高而塑性差的主要原因;焊接热使板件受到低温"退火"而强度降低,从而导致两竖直侧平板件强度甚至低于母材.%Tests on mechanical characteristics of the flat portion, corner portion, virgin steel and full section stub column were conducted for the thick-walled cold formed steel tube with sectional dimension of 200mm × 300mm × 9.2mm.Variation in mechnical properties of the flat and corner portion with passes were analyzed according to the cold forming technology.Strain hardening of thick-walled steel was compared with that in reference [7].The increase of yield strength resulted from the cold-forming work were calculated based on the specifications in North America, China and reference[7]respectively.The results show that both of the first two specifications don't fit for the thick-walled cold formed steel.The specification abroad for prediction of thick-wall cold formed steel stub column is more dangerous than Chinese specification.Widmanstatten microstructure formed in material is the ultimate cause of high strength and low plasticity of the flat portion specimens with welding line.The sweating heat reduces the strength of plate specimens and even results in that the strength of the flat portion bilateral is lower than that of the virgin steel.

  4. Top coal flows in an excavation disturbed zone of high section top coal caving of an extremely steep and thick seam

    Institute of Scientific and Technical Information of China (English)

    Miao Shengjuna; Lai Xingping; Cui Feng

    2011-01-01

    Compared with gentle dip long-wall caving, the length of a working face in fully-mechanized top-coal caving for extremely steep and thick seams is short, while its horizontal section is high with increasing production. But the caving ratio is low, which might result in some disasters, such as roof falls, induced by local and large area collapse of the top coal in a working face and dangers induced by gas accumulation. After the development of cracks and weakening of the coal body, the tall, broken section of the top coal (a granular medium) of an extremely steep seam (over 60°) shows clear characteristics of nonlinear movement, We have thoroughly analyzed the geological environment and mining conditions of an excavation disturbed zone. Based on the results from a physical experiment of large-scale 3D modeling and coupling simulation of top coal-water-gas, we conclude that the weakened top coal can be regarded as a non-continuous medium. We used a particle flow code program to compare and analyze migration processes and the movements of a 30 m high section top coal over time before and after weakening of an extremely steep seam in the Weihuliang coal mine. The results of our simulation,experiment and monitoring show that pre-injection of water and pre-splitting blasting improve caving ability and symmetrical caving, relieve space for large area dynamic collapse of top coal, prolong migration time of noxious gases and release them from the mined out area and so achieve safety in mining.

  5. Initial billet and forging dies shape optimization: Application on an axisymetrical forging with a hammer

    Science.gov (United States)

    Meng, Fanjuan; Labergere, Carl; Lafon, Pascal

    2011-05-01

    In metal forming process, the forging die design is the most important step for products quality control. Reasonable dies shape can not only reduce raw material cost but also improving material flow and eliminating defects. The main objective of this paper is to obtain some optimal parameters of the initial billet and forging dies shape according to the simulation results of a two-step metal forming process (platting step and forging step). To develop this metal forming process optimization system several numerical tools are required: geometric modelling (CATIA V5™), FEM analysis (ABAQUS®), work-flow control and optimization computation (MODEFRONTIER®). This study is done in three stages: simulating the two-step metal forming process, building surrogate meta-models to relate response and variables and optimizing the process by using advanced optimization algorithms. In this paper, a two-step axisymmetric metal forming project was studied as an example. By using our simulation model, we get 581 correct real simulation results totally. According to all these real values, we build the surrogate meta-models and obtain Pareto points for a two-objective optimization process. The choice of a solution in all Pareto points will be done by the engineer who can choose his best values according to their criterions of project.

  6. Evaluation of computational models and cross sections used by MCNP6 for simulation of characteristic X-ray emission from thick targets bombarded by kiloelectronvolt electrons

    Science.gov (United States)

    Poškus, A.

    2016-09-01

    This paper evaluates the accuracy of the single-event (SE) and condensed-history (CH) models of electron transport in MCNP6.1 when simulating characteristic Kα, total K (=Kα + Kβ) and Lα X-ray emission from thick targets bombarded by electrons with energies from 5 keV to 30 keV. It is shown that the MCNP6.1 implementation of the CH model for the K-shell impact ionization leads to underestimation of the K yield by 40% or more for the elements with atomic numbers Z 25. The Lα yields are underestimated by more than an order of magnitude in CH mode, because MCNP6.1 neglects X-ray emission caused by electron-impact ionization of L, M and higher shells in CH mode (the Lα yields calculated in CH mode reflect only X-ray fluorescence, which is mainly caused by photoelectric absorption of bremsstrahlung photons). The X-ray yields calculated by MCNP6.1 in SE mode (using ENDF/B-VII.1 library data) are more accurate: the differences of the calculated and experimental K yields are within the experimental uncertainties for the elements C, Al and Si, and the calculated Kα yields are typically underestimated by (20-30)% for the elements with Z > 25, whereas the Lα yields are underestimated by (60-70)% for the elements with Z > 49. It is also shown that agreement of the experimental X-ray yields with those calculated in SE mode is additionally improved by replacing the ENDF/B inner-shell electron-impact ionization cross sections with the set of cross sections obtained from the distorted-wave Born approximation (DWBA), which are also used in the PENELOPE code system. The latter replacement causes a decrease of the average relative difference of the experimental X-ray yields and the simulation results obtained in SE mode to approximately 10%, which is similar to accuracy achieved with PENELOPE. This confirms that the DWBA inner-shell impact ionization cross sections are significantly more accurate than the corresponding ENDF/B cross sections when energy of incident electrons

  7. Study on the isothermal forging process of MB26 magnesium alloy adaptor

    Directory of Open Access Journals (Sweden)

    Xu Wenchen

    2015-01-01

    Full Text Available The isothermal forging process is an effective method to manufacture complex-shaped components of hard-to-work materials, such as magnesium alloys. This study investigates the isothermal forging process of an MB26 magnesium alloy adaptor with three branches. The results show that two-step forging process is appropriate to form the adaptor forging, which not only improves the filling quality but also reduces the forging load compared with one-step forging process. Moreover, the flow line is distributed along the contour of the complex-shaped adaptor forging.

  8. Medium carbon vanadium micro alloyed steels for drop forging

    Energy Technology Data Exchange (ETDEWEB)

    Jeszensky, Gabor; Plaut, Ronald Lesley

    1992-12-31

    Growing competitiveness of alternative manufacturing routes requires cost minimization in the production of drop forged components. The authors analyse the potential of medium carbon, vanadium microalloyed steels for drop forging. Laboratory and industrial experiments have been carried out emphasizing deformation and temperature cycles, strain rates and dwell times showing a typical processing path, associated mechanical properties and corresponding microstructures. The steels the required levels of mechanical properties on cooling after forging, eliminating subsequent heat treatment. The machinability of V-microalloyed steels is also improved when compared with plain medium carbon steels. (author) 17 refs., 19 figs., 5 tabs.

  9. Critical current densities in Bi-2223 sinter forgings.

    Energy Technology Data Exchange (ETDEWEB)

    Balachandran, U.; Fisher, B. L.; Goretta, K. C.; Harris, N. C.; Murayama, N.

    1999-07-23

    (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) bars, prepared by sinter forging, exhibited good phase purity and strong textures with the c axes of the Bi-2223 grains parallel to the forging direction. The initial zero-field critical current density (J{sub c}) of the bars was 10{sup 3} A/cm{sup 2}, but because the forged bars were uncoated, this value decreased with repeated thermal cycling. J{sub c} as a function of applied magnetic field magnitude and direction roughly followed the dependencies exhibited by Ag-sheathed Bi-2223 tapes, but the forged bars were more strongly dependent on field strength and less strongly dependent on field angle.

  10. Valley Forge National Historical Park Tract and Boundary Data

    Data.gov (United States)

    National Park Service, Department of the Interior — This is an ESRI polygon shapefile of tracts for Valley Forge NHP (VAFO). Tracts shown on inset maps A, B, and C were spatially adjusted (i.e., rubbersheeted) to...

  11. Total quality management of forged products through finite element simulation

    Science.gov (United States)

    Chandra, U.; Rachakonda, S.; Chandrasekharan, S.

    The paper reviews the entire thermo-mechanical history experienced by a complex shaped, high strength forged part during all stages of its manufacturing process, i.e. forging, heat treatment, and machining. It examines the current practice of selecting the process parameters using finite element simulation of forging and quenching operations on an individual basis. Some recent work related to the simulation of aging and machining operations is summarized. The capabilities of several well-known finite element codes for these individual simulations are compared. Then, an integrated simulation approach is presented which will permit the optimization of process parameters for all operations, as opposed to a single operation. This approach will ensure a total quality management of forged products by avoiding costly problems which, under the current practice, are detected only at the end of the manufacturing cycle, i.e. after final machining.

  12. Microstructure optimization design methods of the forging process and applications

    Institute of Scientific and Technical Information of China (English)

    WANG Guangchun; ZHAO Guoqun; GUAN Jing

    2007-01-01

    A microstructure optimization design method of the forging process is proposed. The optimization goal is the fine grain size and homogeneous grain distribution. The optimization object is the forging process parameters and the shape of the preform die. The grain size sub-objective function, the forgings shape sub-objective function and the whole objective function including the shape and the grain size are established, espectively. The detailed optimization steps are given. The microstructure optimization program is developed using the micro-genetic algorithm and the finite element method. Then, the upsetting process of the cylindrical billet is analyzed using a self-developed program. The forging parameters and the shape of preform die of the upsetting process are optimized respectively. The fine size and homogenous distribution of the grain can be achieved by controlling the shape of the preform die and improving the friction condition.

  13. Cross-sectional reference values for mid-upper arm circumference, triceps skinfold thickness and arm fat area of Turkish children and adolescents.

    Science.gov (United States)

    Ozturk, Ahmet; Budak, Nurten; Cicek, Betul; Mazicioglu, M Mumtaz; Bayram, Fahri; Kurtoglu, Selim

    2009-06-01

    The aim of the study was to establish cross-sectional reference values for the mid-upper arm circumference (MUAC), triceps skinfold thickness (TSF) and arm fat area (AFA) of Turkish children and adolescents. In total 5,553 students aged between 6 and 17 years were selected by a multistage sampling method from schools representing city centre, rural and urban areas of Kayseri, Central Anatolia. The MUAC and TSF were measured, and the arm muscle area, arm area, AFA and fat percentage (%) were calculated. The LMS method was employed to calculate the MUAC, TSF and AFA curve parameters. The MUAC, TSF, AFA and fat percentage in each age group were significantly higher in girls than in boys. In boys, the TSF 50th percentile ranged from 7.6 mm at 17 years to 9.0 mm at 11 years; whereas in girls this ranged from 9.4 mm at 6 years to 14.6 mm at 17 years. The MUAC 50th percentile ranged from 17.0 to 23.6 cm in boys, and from 15.6 cm to 20.9 cm in girls. The AFA 50th percentile measurements ranged from 4.5 cm at 6 years to 5.8 cm at 12-14 years in boys; and ranged from 7.2 cm at 6 years to 14.8 cm at 17 years in girls. The percentile distribution was more disperse towards higher TSF and AFA values in boys than in girls.

  14. Characterization of residual stresses in heat treated Ti-6Al-4V forgings by machining induced distortion

    Science.gov (United States)

    Regener, B.; Krempaszky, C.; Werner, E.

    2010-06-01

    To provide a solid base for improved material exploitation in dimensioning calculations it is necessary to determine the stress state in the part prior to service loading. In order to achieve higher material strength at elevated temperatures, the surface temperature gradient with respect to time has to be sufficiently high during heat treatment. This results in non-negligable residual stresses that can reduce the allowable load level upon which yielding occurs. For titanium alloys there are two common heat treatments, namely solution treatment and mill annealing. The latter one is the method of choice within the presented project. Mill annealing is utilized in order to significantly reduce the residual stresses in the parts without loosing much of the improved strength at elevated temperatures. Quantification of residual stresses is done by solving an inverse problem. From the measurement of distortion, induced by dividing the investigated part, the residual stress state can be calculated via analytical modeling or correlation with finite element models. To assure a minimum perturbation of the residual stress state during specimen production, dividing of the part is accomplished by electric discharge machining. The parts of interest are v-shaped prisms with a length of approximatly 450 mm and a thickness in the cross sectional area from about 20 mm to 45 mm. Figure 1(a) shows the forged part and 1(b) the dimensions of the cross section in millimeters as well as the material properties considered in the finite element model. The heat exchange between the part and the environment is modelled as heat transfer by convection superimposed with heat radiation. Since the parts are exposed to air during forging and heat treatment, the surface develops a strongly adhesive oxide layer, the so called alpha-case. After forging the parts are cooled in air and heat treated at a temperature of 720° C for a duration of 120 min. Subsequent air cooling and removing the alpha-case by

  15. Characterization of residual stresses in heat treated Ti-6Al-4V forgings by machining induced distortion

    Directory of Open Access Journals (Sweden)

    Werner E.

    2010-06-01

    Full Text Available To provide a solid base for improved material exploitation in dimensioning calculations it is necessary to determine the stress state in the part prior to service loading. In order to achieve higher material strength at elevated temperatures, the surface temperature gradient with respect to time has to be sufficiently high during heat treatment. This results in non-negligable residual stresses that can reduce the allowable load level upon which yielding occurs. For titanium alloys there are two common heat treatments, namely solution treatment and mill annealing. The latter one is the method of choice within the presented project. Mill annealing is utilized in order to significantly reduce the residual stresses in the parts without loosing much of the improved strength at elevated temperatures. Quantification of residual stresses is done by solving an inverse problem. From the measurement of distortion, induced by dividing the investigated part, the residual stress state can be calculated via analytical modeling or correlation with finite element models. To assure a minimum perturbation of the residual stress state during specimen production, dividing of the part is accomplished by electric discharge machining. The parts of interest are v-shaped prisms with a length of approximatly 450 mm and a thickness in the cross sectional area from about 20 mm to 45 mm. Figure 1(a shows the forged part and 1(b the dimensions of the cross section in millimeters as well as the material properties considered in the finite element model. The heat exchange between the part and the environment is modelled as heat transfer by convection superimposed with heat radiation. Since the parts are exposed to air during forging and heat treatment, the surface develops a strongly adhesive oxide layer, the so called alpha-case. After forging the parts are cooled in air and heat treated at a temperature of 720° C for a duration of 120 min. Subsequent air cooling and

  16. Mechanical properties of the as-forged and the forged-and-milled steels for reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bong Sang; Yoon, Ji Hyun; Kim, Joo Hak; Oh, Yong Jun; Hong, Jun Hwa [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-04-01

    The mechanical properties of the as-forged and the forged and milled SA508-Gr.3 reactor pressure vessel steels were evaluated. The full Charpy impact curves obtained for four different locations in test materials. The various data including yield strengths, tensile strengths, elongations were obtained from the tensile strengths, elongations were obtained from the tensile test results for two locations in test materials. The detailed test results were integrated and analysed in this report. 6 refs., 7 figs., 5 tabs. (Author)

  17. Finite element simulation on press forging of magnesium alloy AZ31 sheets

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Press forging of rectangular box of magnesium alloy AZ31 sheets was investigated at elevated temperatures.The characteristics of metal flow were analyzed on the basis of finite element method(FEM)and experiments.Effects of friction factor and sidewall thickness on metal flow and boss forming were investigated by FEM.The results indicate that the bosses and the sidewall of the rectangular box are formed unevenly due to the uneven flow of the metal.The increase in friction factor at die/sheet interface improves the metal flow pattem and the efficiency of boss forming,but reduces the sidewall uniformity.Decrease in sidewall thickness enhances boss forming efficiency,whereas the punch load increases in this case.The present work can provide rcasonable parameters and design guideline for the practical press foxing process of magnesium alloy sheets.

  18. RIGID-PLASTIC MECHANICAL MODEL FOR THE FORGING METHOD WITH HORIZONTAL V-SHAPED ANVIL

    Institute of Scientific and Technical Information of China (English)

    LIU Zhubai; NI Liyong; LIU Guohui; ZHANG Yongjun; ZHU Wenbo

    2006-01-01

    In order to decrease the anisotropy of mechanical properties, the rigid-plastic mechanical model for the forging method with horizontal V-shaped anvil is presented. The forging method,through the change of anvils shape, is able to control fibrous tissue direction, to improve the anisotropy of mechanical properties of axial forgings, to realize uniform forging. Therefore, the forging method can overcome the defect that conventional forging methods produce. The mechanism of the forging method with horizontal V-shaped anvil and the process of metal deformation are analyzed. The agreement of theoretical analysis with experimental study verifies the fact that the forging method with horizontal V-shaped anvil can control effectively the mechanical properties of axial forgings.

  19. Subclinical hypothyroidism is associated with higher carotid intima-media thickness in cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

    Science.gov (United States)

    Peixoto de Miranda, É J F; Bittencourt, M S; Pereira, A C; Goulart, A C; Santos, I S; Lotufo, P A; Bensenor, I M

    2016-10-01

    Although subclinical hypothyroidism (SCH) is associated with cardiovascular risk, there is scarce data about subclinical atherosclerosis in subjects with SCH. We aimed to analyze the association between SCH and carotid intima-media thickness (IMT) using baseline data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). We included subjects with normal thyroid function (TSH: 0.4-4.0 mIU/l, and normal free thyroxine (FT4): 0.8-1.9 ng/dl) and SCH (TSH ≥ 4.0 mIU/l and normal FT4) evaluated for IMT in a cross-sectional analysis. We excluded individuals using medications that affect thyroid function and those with a history of cardiovascular disease. We performed logistic and linear regression models to evaluate the association with IMT (mean values and categorized at the 75th percentile) as a dependent variable and SCH as an independent variable, adjusted for other cardiovascular risk factors. From 8623 subjects (median age of 50 years; interquartile range: 44-57), 4624 (53.6%) were women, 8095 (93.9%) were euthyroid, and 528 (6.1%) had SCH. Groups varied in age, body mass index, Framingham risk score, Homeostasis Model Assessment for Insulin Resistance (HOMA-IR), C-reactive protein, as well as, IMT, that were all higher in SCH compared to euthyroid participants. SCH is associated with IMT as a continuous variable (β = 0.010, P = 0.036) and IMT >75th percentile: OR = 1.30 (95% CI = 1.06-1.59) in logistic models. Individuals with SCH presented higher IMT compared with euthyroid subjects, even after adjustment for potential confounders. IMT was independently associated with SCH in the baseline of the ELSA-Brasil study. Copyright © 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

  20. 准等壁厚螺杆钻具马达断面型线设计%Section Line Designing of Screw Drill Motor with Quasi Thickness Rubber Bush

    Institute of Scientific and Technical Information of China (English)

    李增亮; 姜明云; 禹超; 盛文慧

    2014-01-01

    分析了等壁厚螺杆钻具马达的性能优点和马达金属外壳的加工方法。针对等壁厚螺杆钻具马达金属外壳内表面存在的加工难题,提出了准等壁厚螺杆钻具马达的设计思路。阐述了准等壁厚螺杆钻具马达金属外壳断面型线的绘制方法,并给出了设计实例。试验分析了准等壁厚和等壁厚螺杆钻具马达的性能。结果表明:准等壁厚螺杆钻具马达不仅具有等壁厚螺杆钻具马达的性能优点,还解决了等壁厚螺杆钻具马达金属外壳电解加工的难题。%The performance benefits of the screw drill motor with the uniform thickness rubber bush and the processing methods of the motor metal shell were analyzed.The screw drill motor with quasi thickness rubber bush was proposed to solve the problems of processing the inner sur-face of the metal shell of the screw drill motor with the uniform thickness rubber bush.The draw-ing method of the metal shell cross section type line of the screw drill motor with quasi thickness rubber bush was elaborated and the section line designing of the screw drill motor with quasi thickness rubber bush was given.Finally,the properties of the screw drill motor with quasi thick-ness rubber bush and the screw drill motor with the uniform thickness rubber bush were analy zed.The result shows that the screw drill motor with quasi thickness rubber bush not only has the same performance advantages with the screw drill motor with the uniform thickness rubber bush but also solves the problems of the electrochemical machining of metal shell of the screw drill mo-tor with the uniform thickness rubber bush.

  1. Mannes of Forging and Perspectives of Knuckle Joint Presses Modernization

    Directory of Open Access Journals (Sweden)

    A. A. Antsifirov

    2014-01-01

    Full Text Available The article raises an issue to enhance technological forging capabilities on the known knuckle joint presses. It provides an illustrated overview of main design types of presses with crank-knuckle, toggle-knuckle, and knuckle joint mechanisms. The article also shows the advantages of the modernization way and improvement just of the active press equipment in terms of quality-to-price ratio, for example, as compared to the similar new foreign press equipment.It gives an overview of features, which provide forging processes owing to kinetic energy accumulated with the moving parts of the known designs of the knuckle joint presses depending on the drive actuating mechanism. Focused attention is drawn to forging on the knuckle joint presses for a time of contact with a work piece to be comparable with the duration of the work piece deformation process on hydraulic forging hammers. This allows us to forge thin-wall products with process automation compared to the forging hammers.Analysis of accumulating processes of kinetic energy by the moving parts of the knuckle joint presses has shown that presses driven by hydraulic cylinders or two screw hydraulic cylinder are the most optimal for technological operations as evidenced by references to domestic and foreign invention certificates and patents. The article presents disadvantages of forging on presses with hydraulic or pneumatic drive. It is a dependence of the deformation force, caused, mainly, by a force of the drive cylinder. The article gives linear movement rate quantities of press moving members depending on the drives of the actuating mechanism. Based on the above analysis of the features to manufacture work pieces on the knuckle joint presses, the article gives the rationale for the relevance of forging in a short period of time, provided that the moving parts of the press accumulate the required kinetic energy. This can be achieved only through modernization and improvement of forging

  2. Forces at the Main Mechanism of a Railbound Forging Manipulator

    Directory of Open Access Journals (Sweden)

    Florian Ion Tiberiu Petrescu

    2015-12-01

    Full Text Available Forging manipulators have become more prevalent in the industry today. They are used to manipulate objects to be forged. The most common forging manipulators are moving on a railway to have a greater precision and stability. They have been called the railbound forging manipulators. In this paper we determine the driving forces of the main mechanism from such manipulator. Forces diagram shows a typical forging manipulator, with the basic motions in operation process: walking, motion of the tong and buffering. The lifting mechanism consists of several parts including linkages, hydraulic drives and motion pairs. Hydraulic drives are with the lifting hydraulic cylinder, the buffer hydraulic cylinder and the leaning hydraulic cylinder, which are individually denoted by c1, c2 and c3. In this work considering that the kinematics is being solved it determines the forces of the mechanism. In the first place shall be calculated all external forces from the mechanism (The inertia forces, gravitational forces and the force of the weight of the cast part. Is then calculated all the forces from couplers. 

  3. Defect analysis of complex-shape aluminum alloy forging

    Institute of Scientific and Technical Information of China (English)

    SHAN De-bin; ZHANG Yan-qiu; WANG Yong; XU Fu-chang; XU Wen-chen; L(U) Yan

    2006-01-01

    The isothermal precision forging was applied for the purpose of forming aluminum alloy with complex shape. The complexity of forging is easy to lead to the occurrence of the defects, such as underfilling, folding, metal flow lines disturbance and fibre breaking. The reasons for the defects were analyzed on the basis of experiments and finite element method(FEM). The results show that the size of flash gutter bridge, the lubricating condition and the deformation process are the main factors influencing the filling qualities of complex-shape aluminum alloy forging. The folding defect is mainly caused by different velocities of filling cavities, fast flow of much metal in one direction and confluence of two or multi metal strands. Improper metal distribution in different regions can cause the flow lines disturbance and fast metal flow in one direction is also a cause of the flow lines disturbance According to the reasons, some measures were taken to improve the quality of the forged parts. These studies can contribute to offering some experiences in making process project and optimizing the process parameters for forging complex-shape aviation products.

  4. Diameters and bone thickness at the margin of the foramen magnum in dry skulls from pediatric population: a cross-sectional anatomical study.

    Science.gov (United States)

    Raguz, Marina; Hrabac, Pero; Sedmak, Dora; Gjurasin, Miroslav; Kovacic, Natasa

    2017-05-01

    The purpose of the study was to estimate the size and bone thickness at the margin of the foramen magnum in a pediatric population. Sixty occipital bone specimens from the collection of macerated skulls at the Department of Anatomy, University of Zagreb, were examined and measured using a vernier scale/caliper. For the purpose of analysis, specimens were divided into two age groups: 1-6 years and 7-18 years of age (before and after the fusion of ossification centers in the occipital bone). We measured the following: antero-posterior and transverse diameters of the foramen magnum, bone thicknesses at the basion, opisthion, two paramedial points on the anterior and posterior margins, and at the occipito-squamous junction. Data presented in this study show that diameters of the foramen magnum increase with age, whereas bone thickness shows variable behavior depending on the measured area. Increases in diameters in specimens from the younger age group and their absence in specimens from older subjects reflect the growth pattern of the basilar part of occipital bone. Variability of bone thickness at the margin of the foramen magnum and lack of its association with age of the subjects may be attributed to various factors and may potentially affect the clinical presentation of compression syndromes at the level of foramen magnum.

  5. Basic rules for rheologic forging process of semisolid alloy

    Institute of Scientific and Technical Information of China (English)

    Shuming Xing; Lizhong Zhang; Jianbo Tan; Chuanlin Zheng; Hanwu Liu; Peng Zhang; Yunhui Du

    2004-01-01

    Semisolid mold forging is a major type of semisolid processing, which is different from neither traditional mold forging nor traditional permanent casting. However, processing defects are often seen in work pieces because of lacking available rules for the process design and control. Some basic rules for the process design and control, simply named the shortest flowing length, pressure filling and the minimum uplifting mold pressure, are advanced in the paper based on amount of researches and experiments. The equations to determine the major process parameters are given out such as the filling pressure, forming pressure and locking mold pressure for the process design and control. The rules and equations are experimentally proved available and applicable by several actual work pieces produced by the semisolid forging process.

  6. Precision forging technologies for magnesium alloy bracket and wheel

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Fundamental investigations on precision forging technology of magnesium alloys were studied. As-cast billet prestraining and a new concept of hollow billet were proposed in order to reduce the maximum forming load. A scheme of isothermal forming and the use of combined female dies were adopted, which can improve the die filling capacity and ensure the manufacture of high quality forgings. By means of the developed technique, AZ80 alloy wheel and AZ31 alloy bracket were produced successfully at suitable process parameters and applied in the automotive industries. The results show that the hot compression of AZ80 magnesium alloy has the peak flow stresses of pre-strained alloy with finer grain, which are lower by 20% than those of as-cast alloy under the same deformation conditions. The forming load is related to contact area and average positive stress on interface during forging process.

  7. Isothermal forging of γ-TiAl based alloys

    Institute of Scientific and Technical Information of China (English)

    黄朝晖

    2003-01-01

    The true stress-strain curves and processing window of Ti-47Al-2Cr-1Nb were set up through thermal physical simulation.A method for refinement of the as-cast+ HIPped structure was submitted,which included twostep deformation with a short intermediate heat-treatment between double deformations.The break-down operation of the canned ingot was performed by the isothermal forging processing mentioned above.The refining mechanism is characterized as breaking and bending of the as-cast+HIPped lamellae,dynamic recrystallization,and static globularization.Thus,a uniform and refined billet microstructure is obtained for the final component by forging operation.The deformation of a model disc is accomplished by the subsequent single-step isothermal forging at 1 100-1 150℃ using a closed compression die.

  8. Investigation of the influence of hybrid layers on the life time of hot forging dies

    OpenAIRE

    Legutko, S.; Meller, A.; Gajek, M.

    2013-01-01

    The paper deals with the issues related in the process of drop forging with special attention paid to the durability of forging tools. It presents the results of industrial investigation of the influence of hybrid layers on hot forging dies. The effectiveness of hybrid layers type nitrided layer/PVD coating applied for extending the life of forging tools whose working surfaces are exposed to such complex exploitation conditions as, among others, cyclically varying high thermal and mechanical ...

  9. New low-carbon steel for hot, warm, or cold forging

    Energy Technology Data Exchange (ETDEWEB)

    Ollilainen, V.; Hocksell, E. [Imatra Steel Oy Ab, Imatra Steelworks (Finland)

    2000-05-01

    The development of a new high-strength steel started from the needs of cold forging and continued into hot- and warm-forging areas. The steel has a very low carbon content (<0.1% C) and chromium-boron alloying. Its hardening is simple: just water quenching without tempering. Hot forgings of this steel are directly quenched from forging temperature, resulting in process cost savings and weight reduction. (orig.)

  10. Research on Integrated Casting and Forging Process of Aluminum Automobile Wheel

    OpenAIRE

    Zhang, Qi; Cao, Miao; ZHANG, DAWEI; Zhang, Shuai; Sun, Jue

    2014-01-01

    Integrated casting and forging process (ICFP) is a new manufacturing method combining the advantages of both casting and forging. Aluminum structure parts, such as aluminum alloy automobile wheel, with complex shape and excellent mechanical properties can be produced by this process. The effects of different process parameters on the ICFP of the automobile wheel were simulated by Forge software. Microstructure of forging region and the nonforging region were studied by experiment. The results...

  11. Mechanical properties of forgings depending on the changes in shape and chemical composition of inclusions

    Directory of Open Access Journals (Sweden)

    O. Híreš

    2010-10-01

    Full Text Available The article deals with mechanical properties of forgings used for special technology in cannon barrels production. The forgings are treated by elctroslag remelting technology (ESR to enhance its plastic properties and yield point. Described experiments are focused on mechanical properties and metallurgical quality (microstructure of steels from which are the forgings made. The article includes microstructure photographs and description of inclusions located in examined steels. Experimental results compare forgings treated by ESR and next ones without ESR.

  12. Fatigue in cold-forging dies: Tool life analysis

    DEFF Research Database (Denmark)

    Skov-Hansen, P.; Bay, Niels; Grønbæk, J.;

    1999-01-01

    In the present investigation it is shown how the tool life of heavily loaded cold-forging dies can be predicted. Low-cycle fatigue and fatigue crack growth testing of the tool materials are used in combination with finite element modelling to obtain predictions of tool lives. In the models...... the number of forming cycles is calculated first to crack initiation and then during crack growth to fatal failure. An investigation of a critical die insert in an industrial cold-forging tool as regards the influence of notch radius, the amount and method of pre-stressing and the selected tool material...

  13. Improving durability of hot forging tools by applying hybrid layers

    Directory of Open Access Journals (Sweden)

    Z. Gronostajski

    2015-10-01

    Full Text Available This paper deals with problems relating to the durability of the dies used for the hot forging of spur gears. The results of industrial tests carried out on dies with a hybrid layer (a nitrided layer (PN + physical vapor deposition (PVD coating applied to improve their durability are presented. Two types of hybrid layers, differing in their PVD coating, were evaluated with regard to their durability improvement effectiveness. The tests have shown that by applying hybrid layers of the nitrided layer/PVD coating type one can effectively increase the durability of hot forging tools.

  14. Fractography analysis of tool samples used for cold forging

    DEFF Research Database (Denmark)

    Dahl, K.V.

    2002-01-01

    Three fractured tool dies used for industrial cold forging have been investigated using light optical microscopy and scanning electron microscopy. Two of the specimens were produced using the traditional Böhler P/M steel grade s790, while the lastspecimen was a third generation P/M steel produced...... using new technology developed by Böhler. All three steels have the same nominal composition of alloying elements. The failure in both types of material occurs as a crack formation at a notch inside ofthe tool. Generally the cold forging dies constructed in third generation steels have a longer lifetime...

  15. 77 FR 14445 - Application for a License To Export Steel Forging

    Science.gov (United States)

    2012-03-09

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Application for a License To Export Steel Forging Pursuant to 10 CFR 110.70(b) ``Public Notice of... Spain. December 15, 2011 head steel head steel February 7, 2012 forging. forging will be XR175...

  16. The prediction of the evolution of grain size of land-gear forging during the die-forging process

    Directory of Open Access Journals (Sweden)

    Lin Gao

    2015-01-01

    Full Text Available The land-gear forgings are the most important structure parts, made of high strength steel 300M. Because of the bad service environment, the microstructure and performance of the part are very strict requirements. In this article the evolution of grain size during the die-forging process is predicted, the volume fraction of dynamic recrystallization, grain refinement and development of grain size in-homogeneity, and the affection of billet shape on the grain size distribution are analyzed. The simulated results show that the grain size differences on the different billet positions are very large at the deformation beginning. But in final forging stage, the difference of the average grain size is smaller. At some center zones of the part the maximum difference of grain size is bigger than 100 μm.

  17. Numerical modelling of damage evolution in ingot forging

    DEFF Research Database (Denmark)

    Christiansen, Peter; Martins, Paulo A.F.; Bay, Niels Oluf;

    2015-01-01

    The ingot forging process is numerically simulated applying both the Shima-Oyane porous plasticity model as a coupled damage model and the uncoupled normalized Cockcroft & Latham criterion. Four different cases including two different lower die angles (120º and 180º) and two different sizes of fe...

  18. Vienna-Rotterdam: Forging the Future Urban strategies compared

    NARCIS (Netherlands)

    Rosemann, J.; Wigmans, G.

    1996-01-01

    De rol van de publieke planning en de mogelijkheid (en ook de wenselijkheid) om de stedelijke ontwikkeling in het postindustriële tijdperk te sturen zijn de centrale thema's van de conferentie "Vienna - Rotterdam: Forging the Future". De conferentie wordt georganiseerd door de bouwkundefaculteiten v

  19. Developments of New Lubricants for Cold Forging of Stainless Steel

    DEFF Research Database (Denmark)

    Steenberg, Thomas; Christensen, Erik; Olesen, P.

    1997-01-01

    Two new lubricant systems for cold forging of stainless steel have been developed. The main component of these systems are FeCl3 and ZnCa2(PO4)2, respectively. Both lubricant systems have been tested using a backward extrusion test. The results show excellent lubricating properties with respect...

  20. 76 FR 168 - Heavy Forged Hand Tools From China

    Science.gov (United States)

    2011-01-03

    ... following classes or kinds of heavy forged hand tools from China: (1) Axes and adzes, (2) bars and wedges... four Domestic Like Products: (1) Axes, adzes, and hewing tools, other than machetes, with or without... Industries: (1) Domestic producers of axes, adzes and hewing tools, other than machetes, with or...

  1. Hot Forging of Nitrogen Alloyed Duplex Stainless Steels

    Institute of Scientific and Technical Information of China (English)

    P.Chandramohan; S.S. Mohamed Nazirudeen; S.S. Ramakrishnan

    2007-01-01

    Duplex stainless steels are gaining global importance because of the need for a high strength corrosion resistant material. Three compositions of this group were selected with three different nitrogen contents viz, 0.15 wt pct (alloy 1), 0.23 wt pct (alloy 2) and 0.32 wt pct (alloy 3). The steels were melted in a high frequency induction furnace and hot forged to various reductions from 16% to 62%. In this work, the effect of hot forging on the ferrite content, hardness, yield strength, impact strength and grain orientation (texture) were studied. Fracture analysis on all the forged specimens using SEM reveals that a size reduction of 48% results in maximum ductility and impact strength as well as minimal ferrite content and grain size. Thus the mechanical properties are found to have a direct correlation to ferrite content and grain size. The highest impact strength was observed in specimens with the smallest grain size, which was observed in specimens forged to 48% reduction in size.

  2. Gao Qingmin:Forging a Legend Back to Life

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    SWORD-MAKER Gao Qingmin first dreamt of making swords when standing by his father at the furnace. As a teenager, he was apprenticed to his blacksmith father Gao Xikun, and schooled in stories of master ironsmiths Ou Yezi and Gan Jiang,both famous for forging highquality Tangxi swords.

  3. Parallelisation of seismic algorithms using PVM and FORGE

    NARCIS (Netherlands)

    Wedemeijer, H.; Cox, H.L.H.; Verschuur, D.J.; Ritsema, I.L.

    1996-01-01

    The processing of seismic data, for the imaging of the earth's subsurface, is pushing current computational possibilities to the limit. In this paper results are presented obtained by optimisation and parallelisation of two innovative seismic algorithms with the use of PVM and FORGE. It shows that w

  4. strength and ductility of forged 1200 aluminum alloy reinforced with ...

    African Journals Online (AJOL)

    eobe

    Results show that forged composites with 106μm had a tensile strength .... W. Ag. Sn. Co. % Composition 0.243 0.004 0.005 0.08 0.01. Element. Ni. Cr. Mo. % Composition .... parameters on the porosity content in Al(Mg)-Al2O3 cast particulate ...

  5. FEM simulation for cold press forging forming of the round-fin heat sink

    Science.gov (United States)

    Wang, Kesheng; Han, Yu; Zhang, Haiyan; Zhang, Lihan

    2013-05-01

    In this paper, the finite element method is used to investigate the forming process of cold press forging for the round-fin heat sink in the automotive lighting. A series of simulations on the round-fin heat sink forming using the program DEFORM were carried out. The blank thickness and friction coefficient on the formation of round-fin were studied, and the tooling structure with counterpressure on the heat sink formation was also investigated. The results show that the blank thickness is very good for the round-fin formation, and the thicker the blank is, the better the round-fin can be formed; and also When both the punch-blank interface and the die-blank interface have the same value of friction factor, the larger value of friction factor is in favor of round-fin forming, the further investigation reveals that the friction at the punch-blank interface has more significant effect on preventing the initiation of flow-through compared with the friction at the die-blank interface, which implies that the punch-blank interface has more significant effect on the material flow in the formation of round-fin. Meanwhile, The tooling structure with counterpressure is helpful to the formation of round-fin heat sink, which not only ensures the height of each round-fin on the heat sink is uniform but also retards the initiation of flow-through on the reverse side of round-fin. In addition, the experiments of press forging process were conducted to validate the finite element analysis, and the simulation results are in good agreement with the experimental data.

  6. Occupational noise exposure in small scale hand tools manufacturing (forging) industry (SSI) in Northern India.

    Science.gov (United States)

    Singh, Lakhwinder Pal; Bhardwaj, Arvind; Deepak, K K; Bedi, Raman

    2009-08-01

    Occupational noise has been recognized as hazardous for the human beings. A high noise level in forging shops is considered to lower the labour productivity and cause illness however occupational noise is being accepted as an integral part of the job. The present study has been carried out in 5 small scale hand tool forging units (SSI) of different sizes in Northern India in Punjab. Noise levels at various sections were measured. OSHA norms for hearing conservation has been incorporated which includes an exchange rate of 5 dB (A), criterion level at 90 dB (A), criterion time of 8 h, threshold level=80 dB (A), upper limit=140 dB (A) and with F/S response rate. Equivalent sound pressure level (L(eq)) has been measured in various sections of these plants. Noise at various sections like hammer section, cutting presses, punching, grinding and barrelling process was found to be >90 dB (A), which is greater than OSHA norms. A cross-sectional study on the basis of questionnaire has been carried out. The results of which revealed that 68% of the workers are not wearing ear protective equipments out of these 50% were not provided with PPE by the company. About 95% of the workers were suffering speech interference though high noise annoyance was reported by only 20%. It has been established that the maximum noise exposure is being taken by the workers as they are working more than 8h a day for six days per week. More than 90% workers are working 12 to 24 h over time per week which lead to very high noise exposure i.e. 50 to 80% per week higher than exposure time/week in USA or European countries(15, 16)).

  7. HIV Infection Is Not Associated with Carotid Intima-Media Thickness in Brazil: A Cross-Sectional Analysis from the INI/ELSA-Brasil Study.

    Science.gov (United States)

    Pacheco, Antonio G; Grinsztejn, Beatriz; Fonseca, Maria de Jesus M da; Griep, Rosane Härter; Lotufo, Paulo; Bensenor, Isabela; Mill, José G; Moreira, Rodrigo de C; Moreira, Ronaldo I; Friedman, Ruth K; Santini-Oliveira, Marilia; Cardoso, Sandra W; Veloso, Valdiléa G; Chor, Dóra

    2016-01-01

    Carotid intima-media thickness (cIMT) has been used as an early marker of atherosclerotic disease in the general population. Recently its role among HIV-infected patients has been questioned. To date, no Brazilian study has compared cIMT in respect to HIV status. We compared data from 535 patients actively followed in a prospective cohort in Rio de Janeiro (HIV group); 88 HIV-negative individuals who were nominated by patients (friend controls-FCs); and 10,943 participants of the ELSA-Brasil study. Linear regression models were used to study associations of the 3 groups and several covariables with cIMT. Propensity scores weighting (PSW) were also employed to balance data. Median thickness in mm (IQR) were 0.54 (0.49,0.62); 0.58 (0.52,0.68); and 0.57 (0.49,0.70), HIV, FCs and ELSA-Brasil groups, respectively (p-value<0.001). The best linear model chosen did not include the group variables, after adjusting for all the variables chosen, showing no difference of cIMT across groups. Similar results were obtained with PSW. Several traditional CVD risk factors were also significantly associated with cIMT: female gender, higher education and higher HDL were negatively associated while risk factors were older age, current/former smoker, AMI/stroke family history, CVD history, hypertension, DM, higher BMI and total cholesterol. We show for the first time in a middle-income setting that cIMT, is not different in HIV-infected patients in Rio de Janeiro compared with 2 different groups of non-HIV-infected individuals. Traditional CVD risk factors are associated with this outcome. Our results point out that high standards of care and prevention for CVD risk factors should always be sought both in the HIV-infected and non-infected populations to prevent CVD-related events.

  8. HIV Infection Is Not Associated with Carotid Intima-Media Thickness in Brazil: A Cross-Sectional Analysis from the INI/ELSA-Brasil Study

    Science.gov (United States)

    Grinsztejn, Beatriz; da Fonseca, Maria de Jesus M.; Griep, Rosane Härter; Lotufo, Paulo; Bensenor, Isabela; Mill, José G.; Moreira, Rodrigo de C.; Moreira, Ronaldo I.; Friedman, Ruth K.; Santini-Oliveira, Marilia; Cardoso, Sandra W.; Veloso, Valdiléa G.; Chor, Dóra

    2016-01-01

    Background Carotid intima-media thickness (cIMT) has been used as an early marker of atherosclerotic disease in the general population. Recently its role among HIV-infected patients has been questioned. To date, no Brazilian study has compared cIMT in respect to HIV status. Methods We compared data from 535 patients actively followed in a prospective cohort in Rio de Janeiro (HIV group); 88 HIV-negative individuals who were nominated by patients (friend controls–FCs); and 10,943 participants of the ELSA-Brasil study. Linear regression models were used to study associations of the 3 groups and several covariables with cIMT. Propensity scores weighting (PSW) were also employed to balance data. Results Median thickness in mm (IQR) were 0.54 (0.49,0.62); 0.58 (0.52,0.68); and 0.57 (0.49,0.70), HIV, FCs and ELSA-Brasil groups, respectively (p-value<0.001). The best linear model chosen did not include the group variables, after adjusting for all the variables chosen, showing no difference of cIMT across groups. Similar results were obtained with PSW. Several traditional CVD risk factors were also significantly associated with cIMT: female gender, higher education and higher HDL were negatively associated while risk factors were older age, current/former smoker, AMI/stroke family history, CVD history, hypertension, DM, higher BMI and total cholesterol. Conclusions We show for the first time in a middle-income setting that cIMT, is not different in HIV-infected patients in Rio de Janeiro compared with 2 different groups of non-HIV-infected individuals. Traditional CVD risk factors are associated with this outcome. Our results point out that high standards of care and prevention for CVD risk factors should always be sought both in the HIV-infected and non-infected populations to prevent CVD-related events. PMID:27391355

  9. Thin- and thick-target cross sections for the production of sup 5 sup 3 Mn and sup 6 sup 0 Fe

    CERN Document Server

    Merchel, S; Herpers, U; Knie, K; Korschinek, G; Leya, I; Michel, R; Rugel, G; Wallner, C

    2000-01-01

    Integral cross sections of the nuclear reactions sup n sup a sup t Fe(p,x) sup 5 sup 3 Mn, sup n sup a sup t Ni(p,x) sup 5 sup 3 Mn and sup n sup a sup t Ni(p,x) sup 6 sup 0 Fe up to proton energies of 2.6 GeV were measured by means of accelerator mass spectrometry. Additionally, elemental production rates from targets placed in an isotropically irradiated iron sphere were determined. They provide the basis to calculate the corresponding neutron-induced cross sections. Both types of nuclear data are needed for the calculation of depth- and size-dependent production rates of the long-lived cosmogenic radionuclides, which gives us the possibility to discuss experimental abundances of sup 5 sup 3 Mn and sup 6 sup 0 Fe in extraterrestrial matter.

  10. Obtention of differential sections in nuclear reactions using a thick target; Obtencion de secciones diferenciales en reacciones nucleares usando un blanco grueso

    Energy Technology Data Exchange (ETDEWEB)

    Chavez R, R

    2000-07-01

    The nuclear reaction analysis (NRA) technique is used mainly for detecting the presence and concentration of light elements of great importance such as: carbon, nitrogen and oxygen. This work has the objective to obtain the differential sections of {sup 16} O and {sup 14} N starting from the irradiation with deuterons of TiSrO{sub 3} samples, of AIN and AIN{sub 2} at energies of 2000 KeV and 1800 KeV respectively. The present work have four chapters; chapter 1 is focused to the physical aspects which takes part in the NRA technique. The technical requirements as well as the necessary equipment for developing the techniques are described in the chapter 2. In chapter 3 it is described the algorithm developed for to obtain the differential sections starting from experimental data, and finally, in chapter 4 are given the results and conclusions. (Author)

  11. Insulin resistance is associated with carotid intima-media thickness in non-diabetic subjects. A cross-sectional analysis of the ELSA-Brasil cohort baseline.

    Science.gov (United States)

    Santos, Itamar S; Bittencourt, Márcio S; Goulart, Alessandra C; Schmidt, Maria Inês; Diniz, Maria de Fátima H S; Lotufo, Paulo A; Benseñor, Isabela M

    2017-05-01

    Epidemiological studies have analyzed the association between carotid intima-media thickness (CIMT) and insulin resistance, glucose levels or glycated hemoglobin with mixed results. We aimed to evaluate the association between CIMT and homeostasis model assessment - insulin resistance (HOMA-IR), fasting and post-load plasma glucose and glycated hemoglobin in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) baseline. We included 8028 participants (aged 35-74 years) without diabetes or overt cardiovascular disease who had complete CIMT data at baseline. We built crude and adjusted linear and binary logistic models to evaluate the association between CIMT and (a) HOMA-IR; (b) fasting plasma glucose; (c) post-load plasma glucose; and (d) glycated hemoglobin. We also built post-hoc models, stratified by sex. In the fully-adjusted linear models, only the association between CIMT (in mm) and HOMA-IR remained significant (β = 0.004; 95% confidence interval [95%CI]:0.001 to 0.006). Consistent with these results, only the association between the highest age- sex- and race-specific CIMT quartile and HOMA-IR was significant in the adjusted logistic model (odds ratio [OR]:1.10; 95% CI:1.04-1.17). The association between HOMA-IR and the highest CIMT quartile remained significant in sex-specific analyses (OR:1.10; 95% CI:1.02-1.20 for men and OR:1.10; 95% CI:1.02-1.20 for women). We did not find an independent association between CIMT and glucose or glycated hemoglobin. We found a direct association between HOMA-IR and CIMT in a large sample of non-diabetic participants. Mechanisms unrelated to glucose homeostasis, as a direct effect of insulin on atherosclerosis, or medial hypertrophy, may be involved. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Anxiety and depressive symptoms are associated with higher carotid intima-media thickness. Cross-sectional analysis from ELSA-Brasil baseline data.

    Science.gov (United States)

    Santos, Itamar S; Goulart, Alessandra C; Brunoni, André R; Kemp, Andrew H; Lotufo, Paulo A; Bensenor, Isabela M

    2015-06-01

    Studies focusing on the association between anxiety/depressive symptoms and accelerated subclinical atherosclerosis have yielded mixed results. Our aim is to examine associations between anxiety/depressive symptoms, common mental disorder (CMD), major depression disorder (MDD) or generalized anxiety disorder (GAD) and carotid intima-media thickness (CIMT) in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) cohort baseline. The ELSA-Brasil baseline assessment included CIMT measurements and the Clinical Interview Schedule - Revised (CIS-R), a validated questionnaire for anxiety/depressive symptoms/diagnoses. We analyzed participants without previous coronary heart disease or stroke, and with high-quality CIMT images. We built regression models to determine whether the CIS-R score, CMD, MDD or GAD were associated with maximal CIMT levels. The study sample comprised 9744 participants. We found that individuals with higher CIS-R scores (Odds ratio for one standard deviation increase [OR]:1.12; 95% confidence interval [95%CI]:1.06-1.19), CMD (OR:1.22; 95%CI:1.07-1.38) and GAD (OR:1.19; 95%CI:1.01-1.41) had significantly higher odds of being classified in the highest age, sex and race-specific CIMT quartile. In the linear models, after adjustment for traditional cardiovascular risk factors, higher CIS-R scores (β:0.005; P = 0.010) and GAD (β:0.010; P = 0.049) were independently associated with CIMT values. Individuals with more symptoms of anxiety and/or depression, or diagnoses of CMD or GAD, had higher CIMT values, compared to peers of same age, sex and race. CIS-R scores and GAD were independently associated with higher CIMT values. These results suggest an association between anxiety/depressive symptoms (and, most notably, GAD) and accelerated subclinical atherosclerosis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. Association of Cardiovascular Risk Factors with Carotid Intima Media Thickness in Patients with Rheumatoid Arthritis with Low Disease Activity Compared to Controls: A Cross-Sectional Study.

    Directory of Open Access Journals (Sweden)

    Deborah F van Breukelen-van der Stoep

    Full Text Available Rheumatoid arthritis (RA has been identified as an independent cardiovascular risk factor. The importance of risk factors such as hypertension and hyperlipidemia in the generation of atherosclerosis in RA patients is unclear. This study analyzed clinical parameters associated with carotid intima media thickness (cIMT in patients with RA.Subjects with RA and healthy controls without RA, both without known cardiovascular disease, were included. Participants underwent a standard physical examination and laboratory measurements including a lipid profile. cIMT was measured semi-automatically by ultrasound.In total 243 RA patients and 117 controls were included. The median RA disease duration was 7 years (IQR 2-14 years. The median DAS28 was 2.4 (IQR 1.6-3.2 and 114 (50.4% of the RA patients were in remission. The presence of RA and cIMT were not associated (univariate analysis. Multivariable regression analysis showed that cIMT in RA patients was associated with age (B = 0.006, P<0.001 and systolic blood pressure (B = 0.003, P = 0.003. In controls, cIMT was associated with age (B = 0.006, P<0.001 and smoking (B = 0.097, P = 0.001.cIMT values were similar between RA patients and controls. Hypertension was strongly associated with cIMT in RA patients. After adjustment, no association between cIMT and specific RA disease characteristics was found in this well treated RA cohort.

  14. Correlation of E-selectin concentrations with carotid intima-media thickness and cardio-metabolic profile of mixed ancestry South Africans: a cross-sectional study.

    Science.gov (United States)

    Zemlin, Annalise E; Matsha, Tandi E; Kengne, Andre P; Hon, Gloudina M; Erasmus, Rajiv T

    2017-01-01

    Background E-selectin, an adhesion molecule, is a specific marker of endothelial dysfunction. High concentrations have been reported in type 2 diabetes and disorders with high risk of cardiovascular disease (CVD). Measurement of carotid intima-media thickness (CIMT) is a surrogate marker of early atherosclerosis. We examined the relationship between E-selectin concentrations, CIMT and cardio-metabolic traits in normo- and hyperglycaemic mixed ancestry South Africans. Methods E-selectin concentrations were determined in 308 subjects from the Cape Town Bellville South Community-based study on a mixed ancestry population. Their correlation with CIMT and cardio-metabolic profile used robust correlations and linear regression models. Results E-selectin concentrations were significantly higher in the hyperglycaemic (median 139.8 µg/L) compared to the normoglycaemic group (median 118.8 µg/L), ( p = 0.0007). Significant differences between the two groups were found for markers of glycaemia and adiposity, but not for CIMT. Significant correlations were found between E-selectin and age, markers of glycaemia and inflammation, central obesity and lipid variables. Associations remained significant only with age, hyperglycaemia and C-reactive protein in robust linear regression models. In similar regressions models, age and gender were the main predictors of CIMT, which was not associated with E-selectin. Conclusions E-selectin concentrations in this study were associated with hyperglycaemia, possibly reflecting early endothelial damage. However, E-selectin was not useful to assess CIMT, a marker of subclinical atherosclerosis, which appeared to be determined by ageing and male gender.

  15. Performance Assessment Method for a Forged Fingerprint Detection Algorithm

    Science.gov (United States)

    Shin, Yong Nyuo; Jun, In-Kyung; Kim, Hyun; Shin, Woochang

    The threat of invasion of privacy and of the illegal appropriation of information both increase with the expansion of the biometrics service environment to open systems. However, while certificates or smart cards can easily be cancelled and reissued if found to be missing, there is no way to recover the unique biometric information of an individual following a security breach. With the recognition that this threat factor may disrupt the large-scale civil service operations approaching implementation, such as electronic ID cards and e-Government systems, many agencies and vendors around the world continue to develop forged fingerprint detection technology, but no objective performance assessment method has, to date, been reported. Therefore, in this paper, we propose a methodology designed to evaluate the objective performance of the forged fingerprint detection technology that is currently attracting a great deal of attention.

  16. Prevention of thinning at disc center during rotary forging

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Presents the simulation and analysis of the rotary forging of a disc using a finite element method, which re veals the thinning at the disc center is caused by higher radial and tangential tensile stresses resulting from the local loading of a rotary die and acting at the center of a workpiece, and proposes a new design of rotary die with a hole opened in its center to prevent the continuous occurrence of shortening in the axial direction and elongation in the tan gential and radial directions, and concludes from simulation results that the rotary die with a hole opened in its center is effective for prevention of thinning or cracking at the center of a disc during rotary forging.

  17. PTA锻焊反应器的制造%Fabrication of Forge Welding PTA Reactor

    Institute of Scientific and Technical Information of China (English)

    李艳

    2014-01-01

    The article introduces several key techniques for fabrication of large Cr-Mo steel forge welding reactor in PTA unit. The chemical composition of material should be controlled to improve the anti-tempered embrittlement ability for Cr-Mo steel; the advanced smelting process and forging technique should be used to assure the large forging quality;the cooling process of normalization for Cr-Mo steel head should be optimized to assure the material property;the reasonable welding process should be used to assure the welding quality of thick wall circumferential seam and reduce the fabrication cost;the overlay welding process should be optimized to assure the overlay welding quality in inner surface of reactor. Finally, it is very important for the Cr-Mo steel pressure vessel to use the proper heat treatment procedure.%本文对PTA装置上的大型铬钼钢锻焊反应器,在制造过程中的几个关键技术进行了介绍:控制材料的化学成分提高铬钼钢材料的抗回火脆化能力;采用先进的冶炼工艺和锻造技术保证大型锻件的质量;优化铬钼钢封头正火热处理中的冷却工艺来保证材料的性能指标;采用合理的焊接工艺,既保证了厚壁环焊缝的焊接质量,又降低了制造成本;优化堆焊工艺,保证了反应器内壁的堆焊质量;正确选择热处理规范,对铬钼钢压力容器至关重要。

  18. Forging Alliances in Interdisciplinary Rehabilitation Research (FAIRR): A Logic Model.

    Science.gov (United States)

    Gill, Simone V; Khetani, Mary A; Yinusa-Nyahkoon, Leanne; McManus, Beth; Gardiner, Paula M; Tickle-Degnen, Linda

    2017-07-01

    In a patient-centered care era, rehabilitation can benefit from researcher-clinician collaboration to effectively and efficiently produce the interdisciplinary science that is needed to improve patient-centered outcomes. The authors propose the use of the Forging Alliances in Interdisciplinary Rehabilitation Research (FAIRR) logic model to provide guidance to rehabilitation scientists and clinicians who are committed to growing their involvement in interdisciplinary rehabilitation research. We describe the importance and key characteristics of the FAIRR model for conducting interdisciplinary rehabilitation research.

  19. Forging process modeling of cone-shaped posts

    Institute of Scientific and Technical Information of China (English)

    Xuefeng Liu; Lingyun Wang; Li Zhang

    2004-01-01

    Using the rigid visco-plastic Finite Element Method (FEM), the process of forging for long cone-shaped posts made of aluminum alloys was modeled and the corresponding distributions of the field variables were obtained based on considering aberrance of grids, dynamic boundary conditions, non-stable process, coupled thermo-mechanical behavior and other special problems.The difficulties in equipment selection and die analysis caused by the long cone shape of post, as well as by pressure calculation were solved.

  20. Constitutive Equation of Superalloy In718 in Hammer Forging Process

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A constitutive equation reflecting the flow behavior ofSuperalloy In718 during the counter-blow hammer forging process was developed in terms of the relationship of flow stress and hot-deformation parameters, such as strain, strain rate, and deformation temperature. A new simplified approach for the complex multi-pass stress-strain curves has been attempted. The simulation curves calculated by constitutive equation are consistent with the experimental data.

  1. A Short Study of Large Rotary Forged Cylinders

    Science.gov (United States)

    1979-06-01

    Bottom) 7 Microstructure at mid-wall of reheat treated rotary 25 forged cylinders - Martensite- Bainite 8 Martensitic microstructure of (a) normalized...also was unsatisfactory (Table 2). The microstructure at the mid-wall of both the top and bottom showed evidence of ferrite and bainite (Figs. 1 and...austenitized, and of bainite , showing that the material transformed to austenite had been in- adequately quenched, since martensite is the desired product

  2. Effects of can parameters on canned-forging process of TiAl base alloy(Ⅱ)--Mechanical behavior

    Institute of Scientific and Technical Information of China (English)

    刘咏; 何双珍; 黄伯云; 韦伟峰; 贺跃辉; 周科朝

    2002-01-01

    By using thermal simulation technique and computer simulation, the conventional canned-forging process of TiAl base alloy was studied. The effect of can parame ters on the mechanical behavior of TiAl alloys with diffe rent H/D ratios was analyzed in this process. The results show that, the pea k stress of TiAl base alloy without canning is far higher than that with canning. Compared with the samples with the same H/D ratio, the peak stress decreases with increa sing can thickness; while compared with the samples with the same can thickness , the peak stress decreases with increasing H/D ratio. The decrease of t he true stress of TiAl base alloy with canning were analyzed according to the theory of plastic deformation and results of computer simulation.

  3. Hot-forging Die Cavity Surface Layer Temperature Gradient Distribution and Determinant

    Institute of Scientific and Technical Information of China (English)

    WANG Huachang; WANG Guan; XIAO Han; WANG Hongfu

    2011-01-01

    Based on the car front-wheel-hub forging forming process of numerical simulation,the temperature gradient expression of forging model cavity near the surface layer was got ten,which illustrates that the forging temperature gradient is related to forging die materials thermal conductivity,specific heat and impact speed,and the correlation coefficient is 0.97.Under the different thermal conductivity,heat capacity and forging speed,the temperature gradient was compared with each other.The paper obtained the relevant laws,which illustrates the temperature gradient relates to these three parameters in a sequence of thermal conductivity > impact speed> specific heat capacity.To reduce thermal stress in the near-surface layer of hot forging cavity,the material with greater thermal conductivity coefficient and specific heat capacity should be used.

  4. Investigation of the influence of hybrid layers on the life time of hot forging dies

    Directory of Open Access Journals (Sweden)

    S. Legutko

    2013-04-01

    Full Text Available The paper deals with the issues related in the process of drop forging with special attention paid to the durability of forging tools. It presents the results of industrial investigation of the influence of hybrid layers on hot forging dies. The effectiveness of hybrid layers type nitrided layer/PVD coating applied for extending the life of forging tools whose working surfaces are exposed to such complex exploitation conditions as, among others, cyclically varying high thermal and mechanical loads, as well as intensive abrasion at raised temperature. The examination has been performed on a set of forging tools made of Unimax steel and intended for forging steel rings of gear box synchronizer in the factory FAS in Swarzedz (Poland.

  5. Influence of Processing Parameters on Grain Size Evolution of a Forged Superalloy

    Science.gov (United States)

    Reyes, L. A.; Páramo, P.; Salas Zamarripa, A.; de la Garza, M.; Guerrero-Mata, M. P.

    2016-01-01

    The microstructure evolution of nickel-based superalloys has a great influence on the mechanical behavior during service conditions. Microstructure modification and the effect of process variables such as forging temperature, die-speed, and tool heating were evaluated after hot die forging of a heat-resistant nickel-based alloy. Forging sequences in a temperature range from 1253 to 1323 K were considered through experimental trials. An Avrami model was applied using finite element data to evaluate the average grain size and recrystallization at different evolution zones. It was observed that sequential forging at final temperatures below 1273 K provided greater grain refinement through time-dependent recrystallization phenomena. This investigation was aim to explore the influence of forging parameters on grain size evolution in order to design a fully homogenous and refined microstructure after hot die forging.

  6. Numerical simulation on forging process of TC4 alloy mounting parts

    Institute of Scientific and Technical Information of China (English)

    L(U) Cheng; ZHANG Li-wen

    2006-01-01

    In order to eliminate forging defects appearing in production, based on the rigid-viscoplastic FEM principle, the DEFORM3D software package was employed to simulate the forming process of TC4 alloy mounting part and to optimize the process parameters. In this simulation, the temperature dependency of the thermal and mechanical properties of material was considered. Based on the simulation, the metal flow and thermomechanical field variables such as stress and damage are obtained.The simulation results show that the forging defects are caused by improper die dimension and the optimized die dimension was proposed. To verify the validity of simulation results, forging experiments were also carried out in a forging plant. The forging experiments show that the optimized die dimension can ensure the quality of forging part, and it can provide reference to improve and optimize die design process.

  7. Effect of Laser Preheating AISI 4140 Specimens for Micro-Forging

    Directory of Open Access Journals (Sweden)

    Jung C.

    2017-06-01

    Full Text Available Many high performance and permanent service parts require suitable material characteristics-high fatigue strength is one of the most important characteristics. For this reason, surface treatment processes are essential to increase the material performance and avoid the use of costly ineffective material. There exist various surface treatment processes for various applications. Each process has advantages and disadvantages and hybridization can solve various problems. The micro-forging process delivers a controlled and uniform surface hardness, but the depth of the forged surface is limited. On the other hand, laser heat treatment can increase the hardness drastically, but the surface may become brittle, which reduces the fatigue life. Laser-assisted micro-forging is a novel hybrid process of laser heat treatment and micro-forging that has the potential to increase the forging depth and relax the stress caused by the high temperature of the forging process.

  8. Research on Integrated Casting and Forging Process of Aluminum Automobile Wheel

    Directory of Open Access Journals (Sweden)

    Qi Zhang

    2014-07-01

    Full Text Available Integrated casting and forging process (ICFP is a new manufacturing method combining the advantages of both casting and forging. Aluminum structure parts, such as aluminum alloy automobile wheel, with complex shape and excellent mechanical properties can be produced by this process. The effects of different process parameters on the ICFP of the automobile wheel were simulated by Forge software. Microstructure of forging region and the nonforging region were studied by experiment. The results show that die temperature, static pressure of the injection piston, forging speed, and material flow have significant influences on the process. Compared with nonforging region, the microstructure of forging region becomes finer, more uniform, and denser. Meanwhile, the casting defects can be removed and mechanical properties improved.

  9. Groping for Quantitative Digital 3-D Image Analysis: An Approach to Quantitative Fluorescence In Situ Hybridization in Thick Tissue Sections of Prostate Carcinoma

    Directory of Open Access Journals (Sweden)

    Karsten Rodenacker

    1997-01-01

    Full Text Available In molecular pathology numerical chromosome aberrations have been found to be decisive for the prognosis of malignancy in tumours. The existence of such aberrations can be detected by interphase fluorescence in situ hybridization (FISH. The gain or loss of certain base sequences in the desoxyribonucleic acid (DNA can be estimated by counting the number of FISH signals per cell nucleus. The quantitative evaluation of such events is a necessary condition for a prospective use in diagnostic pathology. To avoid occlusions of signals, the cell nucleus has to be analyzed in three dimensions. Confocal laser scanning microscopy is the means to obtain series of optical thin sections from fluorescence stained or marked material to fulfill the conditions mentioned above. A graphical user interface (GUI to a software package for display, inspection, count and (semi‐automatic analysis of 3‐D images for pathologists is outlined including the underlying methods of 3‐D image interaction and segmentation developed. The preparative methods are briefly described. Main emphasis is given to the methodical questions of computer‐aided analysis of large 3‐D image data sets for pathologists. Several automated analysis steps can be performed for segmentation and succeeding quantification. However tumour material is in contrast to isolated or cultured cells even for visual inspection, a difficult material. For the present a fully automated digital image analysis of 3‐D data is not in sight. A semi‐automatic segmentation method is thus presented here.

  10. The Effect of Corner Radii and Part Orientation on Stress Distribution of Cold Forging Die

    OpenAIRE

    Ahmad B.  Abdullah; Kam S. Ling; Zahurin Samad

    2008-01-01

    One of the most critical problems in cold forging is the huge stresses generated from the deformation of metal leads to die failure. The distribution of stresses mainly depends on geometry of the die. An approach to optimal design in cold forging die geometry and orientation are presented in this paper. The impression cold forging dies of the Universal joint was generated using three-dimensional CAD modeling software, SolidWorks. This CAD modeling software coupled with FEA tools, COSMOSWorks....

  11. Measurement and Analysis on Hardness and Residual Stress of Heavy Forging after Heat Treatment

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The hardness and residual stress in the forging for cold roller during low temperature tempering, and the relationship of residual stress and cooling temperature of high temperature tempering for heavy forgings were studied. The stress relaxation constant at low temperature tempering and the elasto-plastisity inversion temperature at high temperature tempering were found. The results are of great importance to determine rational tempering cooling process of heavy forgings.

  12. Cross dies forging: A new method to reduce forging force & price up to 80% thanks to FEM method

    Directory of Open Access Journals (Sweden)

    Mansouri Hamid

    2016-01-01

    Full Text Available Purpose of this article was to introduce a new method of forging which is called “Cross Die Forging”. In this method, the required force (load is reduced to the greatest possible degree through elimination of flash channel; however, this would also decrease the positive effect of flash channel, namely filling the gaps and pores within the mold. Cross die forging procedure provides a way for providing a better preform design which ensures that the mold is filled without allowing the material to enter the flash channel. This method has been invented based on the need to decrease the production costs and to use lower tonnage pressing devices for production of heavy parts. This method is an economical method only for parts that: A Has at least one plane of symmetry and the two ends that are perpendicular to the symmetry plane are flat; B Has a weight that makes it impossible to be manufactured by rolling or roll forging processes. Examples of such parts are valve’s body, T-junctions, etc.

  13. Residual Stresses in 21-6-9 Stainless Steel Warm Forgings

    Energy Technology Data Exchange (ETDEWEB)

    Everhart, Wesley A.; Lee, Jordan D.; Broecker, Daniel J.; Bartow, John P.; McQueen, Jamie M.; Switzner, Nathan T.; Neidt, Tod M.; Sisneros, Thomas A.; Brown, Donald W.

    2012-11-14

    Forging residual stresses are detrimental to the production and performance of derived machined parts due to machining distortions, corrosion drivers and fatigue crack drivers. Residual strains in a 21-6-9 stainless steel warm High Energy Rate Forging (HERF) were measured via neutron diffraction. The finite element analysis (FEA) method was used to predict the residual stresses that occur during forging and water quenching. The experimentally measured residual strains were used to calibrate simulations of the three-dimensional residual stress state of the forging. ABAQUS simulation tools predicted residual strains that tend to match with experimental results when varying yield strength is considered.

  14. ... ALICE forges ahead with further detectors

    CERN Multimedia

    2006-01-01

    Following the installation of the HMPID, the project has progressed swiftly with further detectors being lowered into the ALICE cavern. The first supermodule of the ALICE transition radiation detector was successfully installed on 10 October. The TRD collaborators from Germany standing next to the supermodule mounted in a rotating frame (bottom left corner) in the ALICE cavern. In the final configuration, 18 supermodules that make up the transition radiation detector will cylindrically surround the large time projection chamber in the central barrel of the ALICE experiment. Each supermodule is about 7 metre long and consists of 30 drift chambers in six layers. The construction of the modules is a collaboration between five institutes in Germany (Universities of Frankfurt and Heidelberg and Gesellschaft fuer Schwerionenforschung mbH in Darmstadt), Romania (NIPNE Bucharest) and Russia (JINR Dubna) with radiators (See 'Did you know?' section) produced at the University of Muenster, Germany. During the summer, ...

  15. 基于数值模拟的前轴辊锻件精确成形的研究与应用%Research and application of front-axle forging precision forming based on numerical simulation

    Institute of Scientific and Technical Information of China (English)

    魏科; 王高潮; 王志录; 陈小杰; 徐学春

    2012-01-01

    根据辊锻设计要求,论述了汽车前轴辊锻件的弹簧座截面、工字型截面、两端拳头截面各道次变化规律;在各道次变化过程中,依据各截面的尺寸参数变化对辊锻模具进行精确设计并选择合理的坯料,以保证坯料能够充满模具型槽.应用Deform-3D软件对辊锻模具模型进行模拟分析,模拟结果与实际生产结果相吻合,进一步验证了辊锻模具设计的准确性和可靠性.该文的论述对前轴辊锻模具的精确设计及辊锻件的生产提供了理论参考依据.%According to the roll-forging design requirements, the changing rule of roll-foging's spring section, H-shaped cross section and fist section ends was discussed. In each step change process, according to the cross-section's parameters, the roll forging die could be precisely designed, meanwhile, the reasonable billet was selected to ensure that the die cavity could be fully filled. Then, Deform-3D finite element simulation software was used to analyze the roll forging process. The simulation results coincided with the actual production results, which further validate the accuracy and reliability of the roll forging die design. The results provide theoretical guidance on the front axle roll forging die and roll forging precision design.

  16. Methodology for calculating the thickness free of sigma phase in duplex stainless steels large section parts during hiperquenching; Metodologia para el calculo de espesores limite libres de fase sigma durante el hipertemple en piezas de aceros duplex de gran seccion

    Energy Technology Data Exchange (ETDEWEB)

    Jimbert, P.; Guraya, T.; Torregary, A.; Bravo, P.

    2013-06-01

    To achieve the mechanical properties and corrosion resistance desired by duplex stainless steels used by the petrochemical and nuclear industry, parts are subjected to a hiperquenching heat treatment from about 1050 degree centigrade. This avoids the risk of intermetallic precipitation which drastically reduces the properties of these materials. However with increasing depth to which the deposits are present, the thicknesses for such pipes have been increased, resulting in higher levels of demand on all its manufacturing process, including the heat treatment. To avoid the precipitation of intermetallic phases such as sigma phase it is necessary to know the cooling profile in the center of the work piece and for this purpose to know the value of the Surface Heat Transfer Coefficient (h) is essential. This coefficient changes during the hiperquenching and its value is determined experimentally as it depends on several process parameters. Studies reveal that its value is stabilized within a few seconds. We can then assume that to know the cooling profile in the center of large sections it is only necessary to know the stabilized value of h. However, all the studies found in the literature are referred to diameters smaller than 100 mm. This paper has developed a methodology to predict the precipitation of intermetallic phases in duplex stainless steel parts with large thicknesses in industrial facilities from the calculation of h. This methodology allows us to calculate the cooling profiles without wasting any work piece using one or more sensorized patterns with thermocouples and a subsequent simulation with ANSYS. (Author)

  17. A new Friction and Lubrication Test for Cold Forging

    DEFF Research Database (Denmark)

    Bay, Niels; Wibom, Ole; Aalborg Nielsen, J

    1995-01-01

    This paper presents a new friction and lubrication test for cold forging. The test allows controlled variation of the surface expansion in the range 0-2000%, the tool temperature in the range 20-270°C and the sliding length between 0 and infinite. Friction is decreasing with increasing temperature...... in the range 30-150°C. Above this temperature range friction increases. As regards lubricant performance Lubrication Limit Curves (LLC) are plotted in a sliding length-surface enlargement diagram with the tool temperature as a parameter. Larger tool temperature implies lower acceptable surface expansion...

  18. Environmentally Benign Lubricant Systems For Cold, Warm And Hot Forging

    DEFF Research Database (Denmark)

    Bay, Niels

    2010-01-01

    The growing awareness of environmental issues and the requirements to establish solutions diminishing the impact on working environment as well as external environment has initiated ever increasing efforts to develop new, environmentally benign tribological systems for metal forming. The present...... paper gives an overview of these efforts substituting environmentally hazardous lubricants in cold, warm and hot forging. The paper is an extract of the keynote paper [3] written by the author together with eight co-authors referring to collected papers and other information from more than 30 different...

  19. Manufacturing involving forging of multiple objects in contact

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Zhang, W.; Martins, P.A.F.

    Finite element modeling of multi-object manufacturing processes is presented with supporting experiments. The underlying finite element implementation is based on the flow formulation and further coupled with thermal and electrical models to accomplish electro-thermo-mechanical simulation. All...... and dissimilar materials. While being plastically deformed against each other under increasing forging load, the parts dynamically develop their mutual contact interfaces. Comparisons of the final geometry as well as force-displacement curves are evaluated. The potential of simulated applications are discussed...

  20. Modeling Cavitation in ICE Pistons Made with Isothermal Forging

    Directory of Open Access Journals (Sweden)

    V.V. Astanin

    2014-07-01

    Full Text Available Possible causes for cavitations in parts made with an Al-Si eutectic alloy AK12D (AlSi12 were explored with mathematical and physical modeling with involved acoustic emission. Pores were formed from micro-cracks, which appear during the early stages of a deformation process, with the help of micro-stresses appearing at phase boundaries (Al/Si interface due to thermal expansion. At the design stage of isothermal forgings of such products it is recommended to provide a scheme of the deformed shape, which is under uniform compression, to compensate for the inter-phase stresses.

  1. Influence of local mechanical properties of high strength steel from large size forged ingot on ultrasonic wave velocities

    Science.gov (United States)

    Dupont-Marillia, Frederic; Jahazi, Mohamad; Lafreniere, Serge; Belanger, Pierre

    2017-02-01

    In the metallurgical industry, ultrasonic inspection is routinely used for the detection of defects. For the non-destructive inspection of small high strength steel parts, the material can be considered isotropic. However, when the size of the parts under inspection is large, the isotropic material hypothesis does not necessarily hold. The aim of this study is to investigate the effect of the variation in mechanical properties such as grain size, Young's modulus, Poissons ratio, chemical composition on longitudinal and transversal ultrasonic wave velocities. A 2 cm thick slice cut from a 40-ton bainitic steel ingot that was forged and heat treated was divided into 875 parallelepiped samples of 2x4x7 cm3. A metallurgical study has been performed to identify the phase and measure the grain size. Ultrasonic velocity measurements at 2.25 MHz for longitudinal and transversal waves were performed. The original location of the parallelepiped samples in the large forged ingot, and the measured velocities were used to produce an ultrasonic velocity map. Using a local isotropy assumption as well as the local density of the parallelepiped samples calculated from the chemical composition of the ingot provided by a previously published study, Youngs modulus and Poissons ratio were calculated from the longitudinal and transversal wave velocities. Micro-tensile test was used to validate Youngs modulus obtained by the ultrasonic wave velocity and an excellent agreement was observed.

  2. 大锻件 KD 压实锻造工艺模拟研究%Simulation Research of Compaction Forging Process for Large Forgings with KD Method

    Institute of Scientific and Technical Information of China (English)

    徐明昊; 王敬禹; 刘建红

    2013-01-01

      利用数值模拟方法对锻造过程中的锻造温度场、V型砧砧宽和布砧方式等工艺参数对锻件心部质量的影响进行了研究。结果表明,温度梯度、宽大V型砧和交替布砧的方式能够有效地提高锻件心部的压实效果。%The influence of the technological parameters during forging , such as forging temperature field, V shaped anvil width and anvil distribution mode on the quality of forging core is researched by numerical simulation .The result shows that the temperature gradient , V shaped wide anvil and alternating anvil distribution can effectively im-prove the compaction effect of forging core .

  3. 75 FR 67110 - Forged Stainless Steel Flanges From India and Taiwan

    Science.gov (United States)

    2010-11-01

    ... COMMISSION Forged Stainless Steel Flanges From India and Taiwan AGENCY: United States International Trade... stainless steel flanges from India and Taiwan. SUMMARY: The Commission hereby gives notice that it has... determine whether revocation of the antidumping duty orders on forged stainless steel flanges from India...

  4. Forging; Heat Treating and Testing; Technically Oriented Industrial Materials and Process 1: 5898.05.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    The course provides students with advanced and exploratory experience in the area of plastic deformation of metals and in the changing of the physical characteristics of metals by the controlled application and timed removal of heat. Course content includes goals, specific objectives, safety in forge work, forging tools and equipment, industrial…

  5. [Research on the inner wall condition monitoring method of ring forgings based on infrared spectra].

    Science.gov (United States)

    Fu, Xian-bin; Liu, Bin; Wei, Bin; Zhang, Yu-cun; Liu, Zhao-lun

    2015-01-01

    In order to grasp the inner wall condition of ring forgings, an inner wall condition monitoring method based on infrared spectra for ring forgings is proposed in the present paper. Firstly, using infrared spectroscopy the forgings temperature measurement system was built based on the three-level FP-cavity LCTF. The two single radiation spectra from the forgings' surface were got using the three-level FP-cavity LCTF. And the temperature measuring of the surface forgings was achieved according to the infrared double-color temperature measuring principle. The measuring accuracy can be greatly improved by this temperature measurement method. Secondly, on the basis of the Laplace heat conduction differential equation the inner wall condition monitoring model was established by the method of separating variables. The inner wall condition monitoring of ring forgings was realized via combining the temperature data and the forgings own parameter information. Finally, this method is feasible according to the simulation experiment. The inner wall condition monitoring method can provide the theoretical basis for the normal operating of the ring forgings.

  6. Microstructure Modeling of a Ni-Fe-Based Superalloy During the Rotary Forging Process

    Science.gov (United States)

    Loyda, A.; Hernández-Muñoz, G. M.; Reyes, L. A.; Zambrano-Robledo, P.

    2016-06-01

    The microstructure evolution of Ni-Fe superalloys has a great influence on the mechanical behavior during service conditions. The rotary forging process offers an alternative to conventional bulk forming processes where the parts can be rotary forged with a fraction of the force commonly needed by conventional forging techniques. In this investigation, a numerical modeling of microstructure evolution for design and optimization of the hot forging operations has been used to manufacture a heat-resistant nickel-based superalloy. An Avrami model was implemented into finite element commercial platform DEFORM 3D to evaluate the average grain size and recrystallization during the rotary forging process. The simulations were carried out considering three initial temperatures, 980, 1000, and 1050 °C, to obtain the microstructure behavior after rotary forging. The final average grain size of one case was validated by comparing with results of previous experimental work of disk forging operation. This investigation was aimed to explore the influence of the rotary forging process on microstructure evolution in order to obtain a homogenous and refined grain size in the final component.

  7. MM 99.58 Physical modelling of Hammerhead forging, Vertical and Lateral load history

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Eriksen, Morten; Wanheim, Tarras

    1999-01-01

    The present report presents a laboratory setup with hammerhead forging, where the vertical and lateral force history is obtained under different process conditions......The present report presents a laboratory setup with hammerhead forging, where the vertical and lateral force history is obtained under different process conditions...

  8. Winter Weather at Valley Forge 1777-1778: A Lesson in Climatic Reconstruction.

    Science.gov (United States)

    Ansley, Mary Jane; Pritchard, Sandra F.

    1987-01-01

    Notes that the story of George Washington's encampment at Valley Forge is seldom told without reference to the bitter cold winter Washington and his troops endured. Shows how to use historical reports of weather information to allow students to judge for themselves whether the winter at Valley Forge then was harsher than winters in the same area…

  9. RESEARCH ON THE WARM FORGING OF ALUMINUM ALLOYS:DEVELOPMENT OF A FORMULA TO DESCRIBE THE SOFTENING BEHAVIOR OF A2011 IN FORGING PROCESS

    Institute of Scientific and Technical Information of China (English)

    X.H. Zhang, K. Osakada; X. Y. Ruan

    2003-01-01

    To understand the forming behaviour of aluminum alloys, the upsetting test of alu-minum alloys at evaluated temperature is conducted. Because in warm forging theflow stress decreases with increasing straining, which is so-called work softening, noappropriate material formulation is available. For the evaluation of flow stress ofaluminum alloys in warm forging processes, in this paper, a formula is derived byanalyzing the stress data measured at various temperatures. It is demonstrated thatthe formula fits the flow stress obtained from experiment.

  10. 长轴类大锻件自由锻造工艺研究%Research on free-forging process of long-shaft heavy forging

    Institute of Scientific and Technical Information of China (English)

    张鹏; 夏琴香; 李哲林; 谢合清; 潘勇

    2011-01-01

    The traditional forging technology was studied and improved. The 7. 8 t propeller-shaft heavy forging was forged through the 4 t electrohydraulic hammer using the reasonable steel ingot and by squaring with 300 mm width flat anvil, stretching, chamfering and rolling processes. Experimental result shows that the defects, such as the shrinkage cavity, porosity, etc., can be clogged by the reasonable forging process. High mechanical properties of the propeller shaft heavy forgings were obtained after quenching and tempering. The characteristics of simple tool, broad universal and large flexible of free forging were fully utilized in this research. The free-forging of long-shaft heavy forging was realized.%对传统的锻造工艺进行了研究和改进,通过合理选用钢锭及采用宽300 mm平砧压方、拔长、倒棱滚圆等工序,实现用4 t电液锤锻造7.8 t螺旋桨轴大锻件.试验结果证明,合理的锻造工艺路线锻合了钢锭内部的缩孔、疏松等缺陷,所获得的螺旋桨轴大锻件经过锻后调质热处理能得到较好的综合力学性能.项目的研究充分发挥了自由锻造工具简单、通用性强、灵活性大的特点,实现了长轴类大锻件的自由锻造.

  11. The development and production of thermo-mechanically forged tool steel spur gears

    Science.gov (United States)

    Bamberger, E. N.

    1973-01-01

    A development program to establish the feasibility and applicability of high energy rate forging procedures to tool steel spur gears was performed. Included in the study were relatively standard forging procedures as well as a thermo-mechanical process termed ausforming. The subject gear configuration utilized was essentially a standard spur gear having 28 teeth, a pitch diameter of 3.5 inches and a diametral pitch of 8. Initially it had been planned to use a high contact ratio gear design, however, a comprehensive evaluation indicated that severe forging problems would be encountered as a result of the extremely small teeth required by this type of design. The forging studies were successful in achieving gear blanks having integrally formed teeth using both standard and thermo-mechanical forging procedures.

  12. RESEARCH ON INFLUENCE OF TEMPERATURE ON A PRECISION FORGING PROCESS OF BLADE WITH A TENON

    Institute of Scientific and Technical Information of China (English)

    Y.L. Liu; H. Yang; T. Gao; M. Zhan; W. Cai

    2005-01-01

    The blade precision forging process is a forming process with high temperature and large plastic deformation. Interaction of deformation and heat conduction leads to large uneven distribution of temperature. The unevenness of temperature distribution has a great effect on mechanical properties and the microstructure of materials. So it is necessary to consider the influence of temperature on the precision forging process of blades. Taking a blade with a tenon into consideration, a 3D mechanical model in precision forging is built up. The distribution laws of temperature field and the influence of the temperature on the equivalent stress in the process are obtained by using 3-D coupled thermo-mechanical FEM code developed by the authors. The results obtained illustrate that the influence of the temperature field on the blade forging process is considerable. The achievements of predicting microstructure and mechanical properties for forged blades is significant.

  13. HYDROGEN-ASSISTED FRACTURE IN FORGED TYPE 304L AUSTENITIC STAINLESS STEEL

    Energy Technology Data Exchange (ETDEWEB)

    Switzner, Nathan; Neidt, Ted; Hollenbeck, John; Knutson, J.; Everhart, Wes; Hanlin, R. [University of Missouri-Kansas City; Bergen, R. [Precision Metal Products; Balch, D. K. [Sandia Natl Laboratory

    2012-09-06

    Austenitic stainless steels generally have good resistance to hydrogen-assisted fracture; however, structural designs for high-pressure gaseous hydrogen are constrained by the low strength of this class of material. Forging is used to increase the low strength of austenitic stainless steels, thus improving the efficiency of structural designs. Hydrogen-assisted racture, however, depends on microstructural details associated with manufacturing. In this study, hydrogen-assisted fracture of forged type 304L austenitic stainless steel is investigated. Microstructural variation in multi-step forged 304L was achieved by forging at different rates and temperatures, and by process annealing. High internal hydrogen content in forged type 304L austenitic stainless steel is achieved by thermal precharging in gaseous hydrogen and results in as much as 50% reduction of tensile ductility.

  14. Characterization of a Viking Blade Fabricated by Traditional Forging Techniques

    Science.gov (United States)

    Vo, H.; Frazer, D.; Bailey, N.; Traylor, R.; Austin, J.; Pringle, J.; Bickel, J.; Connick, R.; Connick, W.; Hosemann, P.

    2016-12-01

    A team of students from the University of California, Berkeley, participated in a blade-smithing competition hosted by the Minerals, Metals, and Materials Society at the TMS 2015 144th annual meeting and exhibition. Motivated by ancient forging methods, the UC Berkeley team chose to fabricate our blade from historical smithing techniques utilizing naturally-occurring deposits of iron ore. This approach resulted in receiving the "Best Example of a Traditional Blade Process/Ore Smelting Technique" award for our blade named "Berkelium." First, iron-enriched sand was collected from local beaches. Magnetite (Fe3O4) was then extracted from the sand and smelted into individual high- and low-carbon steel ingots. Layers of high- and low-carbon steels were forge-welded together, predominantly by hand, to form a composite material. Optical microscopy, energy dispersive spectroscopy, and Vickers hardness mechanical testing were conducted at different stages throughout the blade-making process to evaluate the microstructure and hardness evolution during formation. It was found that the pre-heat-treated blade microstructure was composed of ferrite and pearlite, and contained many nonmetallic inclusions. A final heat treatment was performed, which caused the average hardness of the blade edge to increase by more than a factor of two, indicating a martensitic transformation.

  15. Characterization of a Viking Blade Fabricated by Traditional Forging Techniques

    Science.gov (United States)

    Vo, H.; Frazer, D.; Bailey, N.; Traylor, R.; Austin, J.; Pringle, J.; Bickel, J.; Connick, R.; Connick, W.; Hosemann, P.

    2016-09-01

    A team of students from the University of California, Berkeley, participated in a blade-smithing competition hosted by the Minerals, Metals, and Materials Society at the TMS 2015 144th annual meeting and exhibition. Motivated by ancient forging methods, the UC Berkeley team chose to fabricate our blade from historical smithing techniques utilizing naturally-occurring deposits of iron ore. This approach resulted in receiving the "Best Example of a Traditional Blade Process/Ore Smelting Technique" award for our blade named "Berkelium." First, iron-enriched sand was collected from local beaches. Magnetite (Fe3O4) was then extracted from the sand and smelted into individual high- and low-carbon steel ingots. Layers of high- and low-carbon steels were forge-welded together, predominantly by hand, to form a composite material. Optical microscopy, energy dispersive spectroscopy, and Vickers hardness mechanical testing were conducted at different stages throughout the blade-making process to evaluate the microstructure and hardness evolution during formation. It was found that the pre-heat-treated blade microstructure was composed of ferrite and pearlite, and contained many nonmetallic inclusions. A final heat treatment was performed, which caused the average hardness of the blade edge to increase by more than a factor of two, indicating a martensitic transformation.

  16. Effect of Homogenization &Quenching Media on the Mechanical Properties of Sintered Hot Forged AISI 9250 P/MSteel Preforms

    Directory of Open Access Journals (Sweden)

    S. Aamani

    2014-10-01

    Full Text Available Present investigation is an attempt to generate experimental data in order to establish the influence of homogenization and cooling media on the mechanical properties of hot forged AISI 9250 sintered P/M steel to square cross-section bars produced using elemental powders. The elemental powders corresponding to final AISI 9250 composition ofFe-0.5%C-0.75%Mn-2.0%Si were taken in an appropriate proportion and blended in a pot mill for a period of 32 hours while maintaining the powder to ball ratio by weight as 1.1:1. Compacts of 28mm diameter and 36mm height were prepared on a 1.0 MN capacity Universal Testing Machine (UTM and using suitable die, punch and bottom insert assembly in the density range of 85±1 percent of theoretical by applying the pressure in the range of 550±10 MPa and by taking pre-weighed powder blend. In all 36 compacts were prepared. These green compacts were coated using the indigenously developed ceramic coating and the same was allowed to dry under the ambient conditions for a period of 14-16 hours. These ceramic coated compacts were re-coated 90° to the previous coating and re-dried under the aforementioned conditions for the same length of time. Ceramic coated compacts were sintered in an electric muffle furnace at 1120±10°C for a period of 120 minutes and subsequently hot forged to square cross-section bars of approximate dimensions of 14mm X 14mm X 95-100mm on a friction screw press of 1.00MN capacity at the sintering temperature itself. Nine forged specimens were oil quenched and remaining 27 forged bars were homogenized at the sintering temperature for a period of 60 minutes followed by quenching nine of them in oil, nine specimens in air and remaining nine were cooled in the furnace itself. Standard tensile specimens were prepared from each set and tested for evaluation of mechanical properties followed by SEM Fractography on the fractured specimen surfaces. Tensile tests results have established that the

  17. Effects of can parameters on canned-forging process of TiAl base alloy(Ⅰ)--Microstructural analyses

    Institute of Scientific and Technical Information of China (English)

    刘咏; 韦伟峰; 黄伯云; 何双珍; 周科朝; 贺跃辉

    2002-01-01

    By using thermal simulation technique, the conventional canned-forging process of TiAl based alloy was studied. The effect of can parameters on the microstruct ures of TiAl alloy was analyzed in this process. The results show that, the defo rmation microstructure of TiAl based alloy without canning is inhomogeneous. In lateral area, crack and shearing lines can be found; while in central area, fine -grained shearing zone can be found. The effect of can is to reduce the seconda ry tensile stress. However, only when the deformation of the steel can is coinci dental with that of TiAl alloy ingot, can this effect be effective. Moreover, a thick can would enhance the microstructural homogeneity in TiAl based alloy. With the H/D ratio of the ingot increasing, the deformation of TiAl alloy would be more unsteady, therefore, a thicker can should be needed.

  18. Computer Οptimization of Geometric Form of Tool and Preform for Closed-die Forging of Compressor Blade Simulator

    Directory of Open Access Journals (Sweden)

    A. V. Botkin

    2014-07-01

    Full Text Available Using the software package DEFORM 3D when developing technology of isothermal forging workpiece blades it is possible to reduce the pre-production time, to improve the quality of forgings and increase lifetime of forging dies. Computer modeling allows to predict the formation of such defects during forging as notches and wrinkles, underfilling of die impression, to estimate tool loads. Preform shape and angular position of the blade simulator were optimized in order to minimize the lateral forces generated during the forging operation.

  19. Using of material-technological modelling for designing production of closed die forgings

    Science.gov (United States)

    Ibrahim, K.; Vorel, I.; Jeníček, Š.; Káňa, J.; Aišman, D.; Kotěšovec, V.

    2017-02-01

    Production of forgings is a complex and demanding process which consists of a number of forging operations and, in many cases, includes post-forge heat treatment. An optimized manufacturing line is a prerequisite for obtaining prime-quality products which in turn are essential to profitable operation of a forging company. Problems may, however, arise from modifications to the manufacturing route due to changing customer needs. As a result, the production may have to be suspended temporarily to enable changeover and optimization. Using material-technological modelling, the required modifications can be tested and optimized under laboratory conditions outside the plant without disrupting the production. Thanks to material-technological modelling, the process parameters can be varied rapidly in response to changes in market requirements. Outcomes of the modelling runs include optimum parameters for the forging part’s manufacturing route, values of mechanical properties, and results of microstructure analysis. This article describes the use of material-technological modelling for exploring the impact of the amount of deformation and the rate of cooling of a particular forged part from the finish-forging temperature on its microstructure and related mechanical properties.

  20. Design and Analysis of a Forging Die for Manufacturing of Multiple Connecting Rods

    Science.gov (United States)

    Megharaj, C. E.; Nagaraj, P. M.; Jeelan Pasha, K.

    2016-09-01

    This paper demonstrates to utilize the hammer capacity by modifying the die design such that forging hammer can manufacture more than one connecting rod in a given forging cycle time. To modify the die design study is carried out to understand the parameters that are required for forging die design. By considering these parameters, forging die is designed using design modelling tool solid edge. This new design now can produce two connecting rods in same capacity hammer. The new design is required to validate by verifying complete filing of metal in die cavities without any defects in it. To verify this, analysis tool DEFORM 3D is used in this project. Before start of validation process it is require to convert 3D generated models in to. STL file format to import the models into the analysis tool DEFORM 3D. After importing these designs they are analysed for material flow into the cavities and energy required to produce two connecting rods in new forging die design. It is found that the forging die design is proper without any defects and also energy graph shows that the forging energy required to produce two connecting rods is within the limit of that hammer capacity. Implementation of this project increases the production of connecting rods by 200% in less than previous cycle time.

  1. Research on Energy-Saving Production Scheduling Based on a Clustering Algorithm for a Forging Enterprise

    Directory of Open Access Journals (Sweden)

    Yifei Tong

    2016-02-01

    Full Text Available Energy efficiency is a buzzword of the 21st century. With the ever growing need for energy efficient and low-carbon production, it is a big challenge for high energy-consumption enterprises to reduce their energy consumption. To this aim, a forging enterprise, DVR (the abbreviation of a forging enterprise, is researched. Firstly, an investigation into the production processes of DVR is given as well as an analysis of forging production. Then, the energy-saving forging scheduling is decomposed into two sub-problems. One is for cutting and machining scheduling, which is similar to traditional machining scheduling. The other one is for forging and heat treatment scheduling. Thirdly, former forging production scheduling is presented and solved based on an improved genetic algorithm. Fourthly, the latter is discussed in detail, followed by proposed dynamic clustering and stacking combination optimization. The proposed stacking optimization requires making the gross weight of forgings as close to the maximum batch capacity as possible. The above research can help reduce the heating times, and increase furnace utilization with high energy efficiency and low carbon emissions.

  2. Identification of Project Risks & Risk Breakdown Structure In Manufacture of Heavy Forgings

    Directory of Open Access Journals (Sweden)

    D.K.Singh

    2014-10-01

    Full Text Available Forging companies, especially in the business of manufacture of heavy forged parts are embedded in the supply chain of critical components of capital goods across various industries. These forged parts form a significant portion of the total raw material requirement of the capital goods equipment and is generally on the critical path of project schedule.Failure to meet delivery schedule poses huge threat to the success of the customer’s project. Delivery of these forged items is delayed in an event of failure to meet customer’s quality requirements.Various other uncertainties during the project lifecyclecan also cause delayed delivery. Accordingly, risk management methodologies when employed by the forging supplier to the manufacturing project can result in successful achievement of delivery timelines. The present study is intended to identify the risks (threats to quality and delivery in manufacture of heavy forged components and create a Risk breakdown structure (RBS as a reference for further risk planning by the forging supplier.

  3. Gear hot forging process robust design based on finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Xuewen, Chen [Henan University of Science and Technology, Luoyang (China); Won, Jung Dong [Jeju National University, Jeju (Korea, Republic of)

    2008-09-15

    During the hot forging process, the shaping property and forging quality will fluctuate because of die wear, manufacturing tolerance, dimensional variation caused by temperature and the different friction conditions, etc. In order to control this variation in performance and to optimize the process parameters, a robust design method is proposed in this paper, based on the finite element method for the hot forging process. During the robust design process, the Taguchi method is the basic robust theory. The finite element analysis is incorporated in order to simulate the hot forging process. In addition, in order to calculate the objective function value, an orthogonal design method is selected to arrange experiments and collect sample points. The ANOVA method is employed to analyze the relationships of the design parameters and design objectives and to find the best parameters. Finally, a case study for the gear hot forging process is conducted. With the objective to reduce the forging force and its variation, the robust design mathematical model is established. The optimal design parameters obtained from this study indicate that the forging force has been reduced and its variation has been controlled

  4. Analysis of the thermo-mechanical deformations in a hot forging tool by numerical simulation

    Science.gov (United States)

    L-Cancelos, R.; Varas, F.; Martín, E.; Viéitez, I.

    2016-03-01

    Although programs have been developed for the design of tools for hot forging, its design is still largely based on the experience of the tool maker. This obliges to build some test matrices and correct their errors to minimize distortions in the forged piece. This phase prior to mass production consumes time and material resources, which makes the final product more expensive. The forging tools are usually constituted by various parts made of different grades of steel, which in turn have different mechanical properties and therefore suffer different degrees of strain. Furthermore, the tools used in the hot forging are exposed to a thermal field that also induces strain or stress based on the degree of confinement of the piece. Therefore, the mechanical behaviour of the assembly is determined by the contact between the different pieces. The numerical simulation allows to analyse different configurations and anticipate possible defects before tool making, thus, reducing the costs of this preliminary phase. In order to improve the dimensional quality of the manufactured parts, the work presented here focuses on the application of a numerical model to a hot forging manufacturing process in order to predict the areas of the forging die subjected to large deformations. The thermo-mechanical model developed and implemented with free software (Code-Aster) includes the strains of thermal origin, strains during forge impact and contact effects. The numerical results are validated with experimental measurements in a tooling set that produces forged crankshafts for the automotive industry. The numerical results show good agreement with the experimental tests. Thereby, a very useful tool for the design of tooling sets for hot forging is achieved.

  5. Effect of Technical Quality of Thermomechanical Die Forging of AA2099 Alloy

    Directory of Open Access Journals (Sweden)

    Łukaszek-Sołek A.

    2014-10-01

    Full Text Available The paper presents the results of investigations of a multicomponent third-generation aluminium alloy, classified as AA2099. The actual forging conditions were determined basing on the assessment of the quality of side surface of specimens subjected to compression in Gleeble 3800 simulator and on flow curves of the alloy, as well as numerical modelling of forging process performed with application of QForm 3D v.7 software. Compression tests were realized at temperatures 400-500 °C, with a strain rate of 0.001-100 s-1, up to a specified constant true strain value of 0.9. Microstructure examination in as-delivered state was performed with application of Leica DM 4000M optical microscope. The obtained results of isothermal deformation of specimens were correlated with the analysis of a characteristic layered pancake-type microstructure. The simulation of die forging of a complex-shape forging (high-current contact tip used in power engineering at the temperature 500 °C, was performed. The shape of a forging makes it possible to fully analyse the influence of thermomechanical process conditions on technical quality of a product. The simulation of forging process showed full correctness of material flow, with no signs of instability. At the same time, the analysis of investigations allowed to prepare and realize the industrial forging trials for a forging of a very complex shape, in a single step, at the temperature 500 °C, with application of thermomechanical treatment. The forging attained high quality of shape and surface. Directional specimens were taken, in order to be subjected to microstructure examination and hardness testing. The data obtained from industrial tests, combined with the results of testing using Gleeble simulator as well as from numerical modelling, make up the guidelines for mechanical processing of AA2099 alloy at the temperatures 470-500 °C.

  6. Decomposition of forging die for high speed machining

    CERN Document Server

    Tapie, Laurent

    2009-01-01

    Today's forging die manufacturing process must be adapted to several evolutions in machining process generation: CAD/CAM models, CAM software solutions and High Speed Machining (HSM). In this context, the adequacy between die shape and HSM process is in the core of machining preparation and process planning approaches. This paper deals with an original approach of machining preparation integrating this adequacy in the main tasks carried out. In this approach, the design of the machining process is based on two levels of decomposition of the geometrical model of a given die with respect to HSM cutting conditions (cutting speed and feed rate) and technological constrains (tool selection, features accessibility). This decomposition assists machining assistant to generate an HSM process. The result of this decomposition is the identification of machining features.

  7. Mechanism of Annealing Softening of Rolled or Forged Tool Steel

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In order to reduce hardness of rolled or forged steels after annealing and improve processability, the diameter and dispersity of carbides were measured by SEM and quantitative metallography. The microstructure of annealed steel was analyzed by TEM. The effects of the factors such as solute atoms, carbides, grain boundary and interphase boundary were studied. The mechanism of annealing softening of steels was analyzed on the examples of steels H13, S5, S7, X45CrNiMo4, which are treated with new technology. The results showed that the softening of H13, S7, S5 is easier obtained by isothermal or slow cooling annealing from slightly below A1, but hardness of X45CrNiMo4 after annealing is reduced effectively by obtaining coarse lamellar pearlite. Economic results can be obtained from good processability.

  8. Numerical optimization of die geometry in open die forging

    DEFF Research Database (Denmark)

    Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

    2013-01-01

    This paper deals with numerical optimization of open die forging of large metallic ingots made by casting implying risk of defects, e.g. central pores. Different material hardening properties and die geometries are combined in order to investigate, which geometry gives rise to maximum closure...... of a centreline hole in a single compression operation. Friction is also taken into account. The numerical analysis indicates that a lower die angle of approximately 140o results in the largest centreline hole closure for a wide range of material hardening. The value of optimum die angle is not influenced...... by friction, which was found only to change the degree of centreline porosity closure in case of small lower die angle....

  9. Forging of Mg-alloys AZ31 and AZ80

    Energy Technology Data Exchange (ETDEWEB)

    Viehweger, B.; Karabet, A.; Duering, M. [Brandenburg University of Technology, Interdisciplinary Research Centre for Lightweight Materials ' ' Panta Rhei' ' , Konrad-Wachsmann-Allee 17, 03046 Cottbus (Germany); Schaeffer, L. [Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil)

    2005-05-01

    Mg-wrought alloys recently became an engineer material of constantly increasing interest. The mechanical properties of extruded Mg-feedstock of the alloys AZ80 and AZ31 indicate their suitability for automotive applications in form of high-quality forgings. Therefore a detailed knowledge about the forming behaviour is of particular importance. In order to compare mechanical properties of available Mg-feedstock qualities compression tests at room temperature have been carried out by applying batches of AZ31- and AZ80-feedstock. Cylindrical specimens were made out of received continuously casted as well as extruded AZ31- and AZ80 - rods. A quantitative analysis of Mg-feedstock's microstructure has been carried out. The characterization of the deformability of applied Mg-feedstock under hot working conditions could be performed by means of uniaxial plain strain upsetting tests at temperatures between 300 and 450 C as well as logarithmic strain rates of 10{sup -1}, 1 and 10s{sup -1}. It is shown that the chosen parameter range ensures an enhanced deformability of continuously as well as extruded Mg-feedstock. The subsequently carried out determination of microstructural evolution could be related to obtained flow stress curves of applied batches of Mg-feedstock. Furthermore, FVM/FEM-systems have been employed in order to design a simplified geometry of heated forging dies suitable for forging tests. The tests have been carried out by means of a hydraulic press. During the tests their punch velocity has been varied between 1 and 40 mm/s. Hence numerically simulated results could be confirmed by practical tests. Exemplary forgings of a simplified shape were made out of all applied batches of Mg-feedstock. No remarkable failures have been detected. (Abstract Copyright [2005], Wiley Periodicals, Inc.) [German] Das Interesse an Mg-Knetlegierungen als Konstruktionswerkstoff fuer automobile Anwendung ist in juengster Zeit stark gewachsen. Daher ist eine detaillierte

  10. 基于DEFORM和正交试验法的前轴辊锻工艺优化%Research on optimization of front-axle roll forging technique based on DEFORM-3D and orthogonal experimental method

    Institute of Scientific and Technical Information of China (English)

    魏科; 王高潮; 李宁; 王志录

    2012-01-01

    正交试验主要用于解决科研和生产中多因素、多水平的问题,运用正交试验法可以在减少试验次数的情况下获得最佳的参数组合,可有效节约人力、物力和时间.在DEFORM-3D有限元数值模拟过程中应用正交试验优化设计方法,对前轴制坯辊锻模具弹簧座截面的圆角值、辊锻模具角速度、摩擦因子及坯料初始温度四因素、三水平问题,进行前轴制坯辊锻模具结构及工艺优化研究,分析影响前轴辊锻成形过程中最大成形载荷的因素,研究结果有利于前轴辊锻模具结构及工艺的优化,而且可有效提高辊锻模具的使用寿命.%The structure of front axle roll forging die and the roll forging process were optimized based on orthogonal experimental design method, using DEF0RM-3D software in finite element numerical simulation, adopting three levels and four factors, the latter including the fillet values of the spring seat section of the front axle roll forging die, the angular velocity of the roll forging die, the friction factor and the initial temperature of billets. The effecting factors of maximal forming load in the roll forging process of front axle were analyzed. The results can also increase the service life of roll forging die.

  11. Follow-up of hearing thresholds among forge hammering workers

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, A.A.; Mikael, R.A.; Faris, R. (Ain Shams Univ., Abbasia, Cairo (Egypt))

    1989-01-01

    Hearing threshold was reexamined in a group of forge hammering workers investigated 8 years ago with consideration of the age effect and of auditory symptoms. Workers were exposed to impact noise that ranged from 112 to 139 dB(A)--at an irregular rate of 20 to 50 drop/minute--and a continuous background noise that ranged from 90 to 94 dB(A). Similar to what was observed 8 years ago, the present permanent threshold shift (PTS) showed a maximum notch at the frequency of 6 kHz and considerable elevations at the frequencies of 0.25-1 kHz. The age-corrected PTS and the postexposure hearing threshold were significantly higher than the corresponding previous values at the frequencies 0.25, 0.5, 1, and 8 kHz only. The rise was more evident at the low than at the high frequencies. Temporary threshold shift (TTS) values were significantly less than those 8 years ago. Contrary to the previous TTS, the present TTS were higher at low than at high frequencies. Although progression of PTS at the frequencies 0.25 and 0.5 kHz was continuous throughout the observed durations of exposure, progression at higher frequencies occurred essentially in the first 10 to 15 years of exposure. Thereafter, it followed a much slower rate. Tinnitus was significantly associated with difficulty in hearing the human voice and with elevation of PTS at all the tested frequencies, while acoustic after-image was significantly associated with increment of PTS at the frequencies 0.25-2 kHz. No relation between PTS and smoking was found. PTS at low frequencies may provide an indication of progression of hearing damage when the sensitivity at 6 and 4 kHz diminishes after prolonged years of exposure. Tinnitus and acoustic after-image are related to the auditory effect of forge hammering noise.

  12. Hot Superplastic Powder Forging for Transparent nanocrystalline Ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, W. Roger

    2006-05-22

    The program explored a completely new, economical method of manufacturing nanocrystalline ceramics, Hot Superplastic Powder Forging (HSPF). The goal of the work was the development of nanocrystalline/low porosity optically transparent zirconia/alumina. The high optical transparency should result from lack of grain boundary scattering since grains will be smaller than one tenth the wavelength of light and from elimination of porosity. An important technological potential for this process is manufacturing of envelopes for high-pressure sodium vapor lamps. The technique for fabricating monolithic nanocrystalline material does not begin with powder whose particle diameter is <100 nm as is commonly done. Instead it begins with powder whose particle diameter is on the order of 10-100 microns but contains nanocrystalline crystallites <<100 nm. Spherical particles are quenched from a melt and heat treated to achieve the desired microstructure. Under a moderate pressure within a die or a mold at temperatures of 1100C to 1300C densification is by plastic flow of superplastic particles. A nanocrystalline microstructure results, though some features are greater than 100nm. It was found, for instance, that in the fully dense Al2O3-ZrO2 eutectic specimens that a bicontinuous microstructure exists containing <100 nm ZrO2 particles in a matrix of Al2O3 grains extending over 1-2 microns. Crystallization, growth, phase development and creep during hot pressing and forging were studied for several compositions and so provided some details on development of polycrystalline microstructure from heating quenched ceramics.

  13. Laser-dispersing of forging tools using AlN-ceramics

    Science.gov (United States)

    Noelke, C.; Luecke, M.; Kaierle, S.; Wesling, V.; Overmeyer, L.

    2014-02-01

    Forging tools for aluminum work pieces show an increased adhesive wear due to cold welding during the forging process. Laser dispersing offers at this point a great potential to fabricate protective layers or tracks with tailored properties that reduce abrasive or adhesive wear at the surface of highly stressed components. Using different process strategies, four metal ceramic compounds applied on two substrate geometries were investigated regarding their structural and mechanical properties and their performance level. The subsequent forging tests have pointed out a positive effect and less adhesive residuals on the laser dispersed tool surface.

  14. The Effect of Corner Radii and Part Orientation on Stress Distribution of Cold Forging Die

    Directory of Open Access Journals (Sweden)

    Ahmad B.  Abdullah

    2008-01-01

    Full Text Available One of the most critical problems in cold forging is the huge stresses generated from the deformation of metal leads to die failure. The distribution of stresses mainly depends on geometry of the die. An approach to optimal design in cold forging die geometry and orientation are presented in this paper. The impression cold forging dies of the Universal joint was generated using three-dimensional CAD modeling software, SolidWorks. This CAD modeling software coupled with FEA tools, COSMOSWorks. The paper emphasizes on effect of the corner radius and dies orientation on stress distribution.

  15. Forge, Arquillian, Swarm and Spring Boot: All play and no effort makes Simon a productive boy

    CERN Document Server

    CERN. Geneva

    2017-01-01

    During this live coding session, Simon will shine some light on a range productivity tools that make software development a pleasure rather than a chore. Simon will live code 2 applications; a Java EE application, with JBoss Forge which uses JPA, Bean Validation, REST and Angular. We’ll test this application using Arquillian from within JBoss Forge. We’ll also show how a Java EE microservice can be developed in Forge and run using JBoss Swarm. The second application will be developed on Spring Boot and using JRebel we’ll rapidly develop and run a Spring application. Attendees will learn how to write code productively using tools designed for developers.

  16. Microstructural evolution and mechanical properties of hypereutectic Al–Si alloy processed by liquid die forging

    Indian Academy of Sciences (India)

    F F Wu; S T Li; G A Zhang; F Jiang

    2014-08-01

    The microstructural evolution and mechanical properties of a hypereutectic Al–Si alloy processed by liquid die forging were investigated. It is found that the grain size of the primary Si was significantly reduced by liquid die forging with increased pressure. The volume fraction of eutectic silicon was decreased with increased pressure. By liquid die forging with pressure up to 180 MPa, the average size of the primary Si was reduced to about 18 m, which results in the remarkable increase in the fracture strength and hardness of the hypereutectic Al–Si alloy.

  17. Qualitative Research of AZ31 Magnesium Alloy Aircraft Brackets Produced by a New Forging Method

    Directory of Open Access Journals (Sweden)

    Dziubińska A.

    2016-06-01

    Full Text Available The paper reports a selection of numerical and experimental results of a new closed-die forging method for producing AZ31 magnesium alloy aircraft brackets with one rib. The numerical modelling of the new forming process was performed by the finite element method.The distributions of stresses, strains, temperature and forces were examined. The numerical results confirmed that the forgings produced by the new forming method are correct. For this reason, the new forming process was verified experimentally. The experimental results showed good agreement with the numerical results. The produced forgings of AZ31 magnesium alloy aircraft brackets with one rib were then subjected to qualitative tests.

  18. 径向精密锻造机V字锥形锤砧锻造分析及数值模拟%Deformation Analysis and Numerical Simulation of V-shaped Cone Anvil Forging in the Fine Forging Machine

    Institute of Scientific and Technical Information of China (English)

    王连东; 高全德; 梁晨; 刘助柏; 张健; 刘唯唯

    2011-01-01

    A new type V-shaped cone anvil is developed to improve the transverse mechanical property of axial forgings in fine forging machine. Two V-shaped cone whose opening opposite is welded by piling up on the main working inclined planes which being located both sides of the fixed diameter area of the anvil. The mobility of the metal under the V-shaped cone and the deformation on the meridian plane and the transverse section is analysed, the numerical simulation is done for common anvil forging and V-shaped cone anvil forging with the DEFORM soft, and the results is compared for the stress and strain at the typical points on the chosen five transverse sections. It is revealed that when V-shaped cone anvil is used, the transverse mobility of metal is enhanced, the equivalent stress and equivalent strain increased, the deformation diversity decreased by 30%, the stress state in the zone around the axis improved, and the axial tension stress at the central point cut down by 50%. It is revealed by the production of the mandrel forgings that the mechanical property is raised effectively.%为改善精密锻造机锻造轴类件横向性能,设计一种新型锤砧——V字锥形锤砧,即在普通锤砧定径区两侧的主工作斜面上堆焊开口相反的两个V字锥形突起.对V字锥形下端的金属流动情况及坯料子午面与横截面上的变形进行分析,运用DEFORM软件对普通锤砧锻造与V字锥形锤砧锻造进行数值模拟,比较选定的5个横截面上典型点的应力应变,结果表明:使用V字锥形锤砧锻造,增加了金属的横向流动性,变形区的等效应变等效应力增大;减小了变形差异程度,横截面上各点的变形差异程度减小30%以上;改善了轴线心部的应力状态,中心点的轴向拉应力减小50%.生产实践表明,使用V字锥形锤砧替代普通锤砧锻造芯轴,有效提高了锻件的力学性能.

  19. A pass planning method for multi-hit stretching of heavy forgings by integration of a semi-analytical technique and degrees-reduced finite element

    Science.gov (United States)

    Cui, Zhenshan; Chen, Wen; Sui, Dashan; Liu, Juan

    2013-05-01

    A pass planning method for multi-pass and multi-hit stretching of heavy forgings is proposed, which composes of a semi-analytical procedure and a degrees-reduced finite element code. The semi-analytical procedure is based on a kinematically admissible velocity and Markov variational principle, and can be applied to roughly calculate the deformed shape and working force for stretch forging process for work-piece which has vertical and lateral symmetrical lines in cross-section. Meanwhile, in order to obtain the distributions of metal flow, temperature, strain and stress in detail, a degrees-reduced thermo-mechanical coupled rigid finite element code is developed. In this code, the instantaneous deformation zone is specially extracted from the total domain and simulated for metal flow, while the total domain is used to simulate the evolution of thermal field. Taking the semi-analytical method as a solver, the pass planning procedure for stretch forging is developed, and the degrees-reduced finite element code is used as a supplement to check the rationality of the planed pass schedule. An example is implemented to demonstrate the application of the proposed technique.

  20. Theoretical and experimental research of hammer forging process of RIM from AZ31 magnesium alloy

    Directory of Open Access Journals (Sweden)

    A. Gontarz

    2014-10-01

    Full Text Available The results of theoretical analysis and experimental tests of hammer forging process of rim part from AZ31 magnesium alloy are presented in this paper. On the basis of numerical simulation results, the analysis of limiting phenomena was made. These phenomena include: possibility of overlapping presence, not filling of die impression, overheating of material and cracks. The results of theoretical analysis provided the support for planning of experimental tests in industrial conditions. Forging tests were conducted in one of Polish forming plants, applying steam-air hammer of blow energy 63 kJ. On the basis of experimental verification, it was stated that it is possible to obtain rim forging from AZ31 alloy of assumed quality in the hammer forging process.

  1. Sensitivity Analysis Based Multiple Objective Preform Die Shape Optimal Design in Metal Forging

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The multiple objective preform design optimization was put forward. The final forging's shape and deformation uniformity were considered in the multiple objective. The objective is to optimize the shape and the deformation uniformity of the final forging at the same time so that a more high integrate quality of the final forging can be obtained. The total objective was assembled by the shape and uniformity objective using the weight adding method. The preform die shape is presented by cubic B-spline curves. The control points of B-spline curves are used as the design variables. The forms of the total objective function, shape and uniformity sub-objective function are given. The sensitivities of the total objective function and the sub-objective functions with respect to the design variables are developed. Using this method, the preform die shape of an H-shaped forging process is optimally designed. The optimization results are very satisfactory.

  2. Spatial Vegetation Data for Valley Forge National Historical Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The vegetation and landcover of Valley Forge National Historical Park (VAFO) were mapped to the association level of the National Vegetation Classification System...

  3. Color Orthorectified Photomosaic for Valley Forge National Historical Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Orthorectified color infrared Imagine image of Valley Forge NHP. Produced from 49 color infrared photos taken September 1999. Orthorectification accomplished with...

  4. Simulation and Analysis of Microstructure Evolution of IN718 in Rotary Forgings by FEM

    Institute of Scientific and Technical Information of China (English)

    YU Zhong-qi; MA Qiu; LIN Zhong-qin

    2008-01-01

    A numerical analysis was performed to study the influence of process parameters on the microstructure evolution of IN718 alloy in rotary forging using the finite element method (FEM).For this purpose,a constitutive equation considering the effects of strain hardening and dynamic softening of IN718 alloy was built.The constitutive equation and microstructure models were implemented into the finite element code to investigate the microstructure evolution during rotary forging subject to large deformations.The simulations were carried out in the ratio of initial height to diameter range 0.2-0.8,the angle of the rocker 3°-7° and the relative feed per revolution range 0.01-0.1 r-1.The research results revealed the deformation mechanism and the correlation of process parameters with the grain size evolution of IN718 alloy during rotary forging.These provide evidence for the selection of rotary forging parameters.

  5. Field Plot Points Modified for Valley Forge National Historical Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This shapefile includes the locations of vegetation classification sampling plots used to develop an association-level vegetation classification of Valley Forge...

  6. Numerical analysis of rheological and tribological behavior influence on 16MnCr5 forging fibering

    Science.gov (United States)

    Gavrus, A.; Pintilie, D.; Nedelcu, R.

    2016-10-01

    The present research work is focus on the influence of the rheological constitutive equation and friction law formulation on 16MnCr5 forging fibering. Numerical analysis using FE Forge® and Abaqus code show the importance of the rheological softening terms on the metals fibers morphology and position coordinate. Calibration of friction law and sensitivity of softening parameters corresponding to a Hansel-Spittel rheological equation have been studied.

  7. Establishment of a Process for Creep Forging Aluminum Alloy Weapon Components

    Science.gov (United States)

    1978-04-01

    the important powder particle character- istics are mean particle size and size distribution, dendritic cell size and pattern, internal voids , and...Geometry Forging No. 26 (Fig. 53) showed excellent die filling except for a slight underfill at the tallest rib. Minor cracking also occurred over a small...Much cracking and underfill In rib detal1. 0.2 750 400 1 Some cracking Trimmed weight, 3.0 lb. 0.1 830 150 - Forged

  8. Development of strategies for saving energy by temperature reduction in warm forging processes

    Science.gov (United States)

    Varela, Sonia; Santos, Maite; Vadillo, Leire; Idoyaga, Zuriñe; Valbuena, Óscar

    2016-10-01

    This paper is associated to the European policy of increasing efficiency in raw material and energy usage. This policy becomes even more important in sectors consuming high amount of resources, like hot forging industry, where material costs sums up to 50% of component price and energy ones are continuously raising. The warm forging shows a clear potential of raw material reduction (near-net-shape components) and also of energy saving (forging temperature under 1000°C). However and due to the increment of the energy costs, new solutions are required by the forging sector in order to reduce the temperature below 900°C. The reported research is based on several approaches to reduce the forging temperature applied to a flanged shaft of the automotive sector as demonstration case. The developed investigations have included several aspects: raw material, process parameters, tools and dies behavior during forging process and also metallographic evaluation of the forged parts. This paper summarizes analysis of the ductility and the admissible forces of the flanged shaft material Ck45 in as-supplied state (as-rolled) and also in two additional heat treated states. Hot compression and tensile tests using a GLEEBLE 3800C Thermo mechanical simulator have been performed pursuing this target. In the same way, a coupled numerical model based on Finite Element Method (FEM) has been developed to predict the material flow, the forging loads and the stresses on the tools at lower temperature with the new heat treatments of the raw material. In order to validate the previous development, experimental trials at 850 °C and 750 °C were carried out in a mechanical press and the results were very promising.

  9. FEM Analysis and Experimental Verification of the Integral Forging Process for AP1000 Primary Coolant Pipe

    Science.gov (United States)

    Wang, Shenglong; Yu, Xiaoyi; Yang, Bin; Zhang, Mingxian; Wu, Huanchun

    2016-10-01

    AP1000 primary coolant pipes must be manufactured by integral forging technology according to the designer—Westinghouse Electric Co. The characteristics of these large, special-shaped pipes create nonuniform temperatures, effective stress, and effective strain during shaping of the pipes. This paper presents a three-dimensional finite element simulation (3D FEM) of the integral forging process, and qualitatively evaluates the likelihood of forging defects. By analyzing the evolution histories of the three field variables, we concluded that the initial forging temperature should be strictly controlled within the interval 1123 K to 1423 K (850 °C to 1150 °C) to avoid second-phase precipitation. In the hard deformation zones, small strains do not contribute to recrystallization resulting in coarse grains. Conversely, in the free deformation zone, the large strains can contribute to the dynamic recrystallization, favoring grain refinement and closure of voids. Cracks are likely to appear, however, on the workpiece surface when forging leads to large deformations. Based on the simulation results, an eligible workpiece with good mechanical properties, few macroscopic defects, and favorable grain size has been successfully forged by experiments at an industrial scale, which validates the FEM simulation.

  10. Deformation, recrystallization, strength, and fracture of press-forged ceramic crystals.

    Science.gov (United States)

    Rice, R. W.

    1972-01-01

    Sapphire and ruby were very difficult to press-forge because they deformed without cracking only in a limited temperature range before they melted. Spinel crystals were somewhat easier and MgO, CaO, and TiC crystals much easier to forge. The degree of recrystallization that occurred during forging (which was related to the ease and type of slip intersections) varied from essentially zero in Al2O3 to complete (i.e., random polycrystalline bodies were produced) in CaO. Forging of bi- and polycrystalline bodies produced incoherent bodies as a result of grain-boundary sliding. Strengths of the forged crystals were comparable to those of dense polycrystalline bodies of similar grain size. However, forged and recrystallized CaO crystals were ductile at lower temperatures than dense hot-pressed CaO. This behavior is attributed to reduced grain-boundary impurities and porosity. Fracture origins could be located, indicating that fracture in the CaO occurs internally as a result of surface work hardening caused by machining.-

  11. Thermomechanical Response of the Rotary Forged Wha Over a Wide Range of Strain Rates and Temperatures

    Science.gov (United States)

    Guo, W. G.; Qu, C.; Liu, F. L.

    This paper is to understand and model the thermomechanical response of the rotary forged WHA, uniaxial compression and tension tests are performed on cylindrical samples, using a material testing machines and the split Hopkinson bar technique. True strains exceeding 40% are achieved in these tests over the range of strain rates from 0.001/s to about 7,000/s, and at initial temperatures from 77K to 1,073K. The results show: 1) the WHA displays a pronounced changing orientation due to mechanical processing, that is, the material is inhomogeneous along the section; 2) the dynamic strain aging occurs at temperatures over 700K and in a strain rate of 10-3 1/s; 3) failure strains decrease with increasing strain rate under uniaxial tension, it is about 1.2% at a strain rate of 1,000 1/s; and 4) flow stress of WHA strongly depends on temperatures and strain rates. Finally, based on the mechanism of dislocation motion, the parameters of a physically-based model are estimated by the experimental results. A good agreement between the modeling prediction and experiments was obtained.

  12. Movement Synchrony Forges Social Bonds Across Group Divides

    Directory of Open Access Journals (Sweden)

    Bahar eTuncgenc

    2016-05-01

    Full Text Available Group dynamics play an important role in the social interactions of both children and adults. A large amount of research has shown that merely being allocated to arbitrarily defined groups can evoke disproportionately positive attitudes toward one’s in-group and negative attitudes toward out-groups, and that these biases emerge in early childhood. This prompts important empirical questions with far-reaching theoretical and applied significance. How robust are these inter-group biases? Can biases be mitigated by behaviors known to bond individuals and groups together? How can bonds be forged across existing group divides? To explore these questions, we examined the bonding effects of interpersonal synchrony on minimally constructed groups in a controlled experiment. In-group and out-group bonding were assessed using questionnaires administered before and after a task in which groups performed movements either synchronously or non-synchronously in a between-participants design. We also developed an implicit behavioral measure, the Island Game, in which physical proximity was used as an indirect measure of interpersonal closeness. Self-report and behavioral measures showed increased bonding between groups after synchronous movement. Bonding with the out-group was significantly higher in the condition in which movements were performed synchronously than when movements were performed non-synchronously between groups. The findings are discussed in terms of their importance for the developmental social psychology of group dynamics as well as their implications for applied intervention programs.

  13. Forged seal detection based on the seal overlay metric.

    Science.gov (United States)

    Lee, Joong; Kong, Seong G; Lee, Young-Soo; Moon, Ki-Woong; Jeon, Oc-Yeub; Han, Jong Hyun; Lee, Bong-Woo; Seo, Joong-Suk

    2012-01-10

    This paper describes a method for verifying the authenticity of a seal impression imprinted on a document based on the seal overlay metric, which refers to the ratio of an effective seal impression pattern and the noise in the neighborhood of the reference impression region. A reference seal pattern is obtained by taking the average of a number of high-quality impressions of a genuine seal. A target seal impression to be examined, often on paper with some background texts and lines, is segmented out from the background by an adaptive threshold applied to the histogram of color components. The segmented target seal impression is then spatially aligned with the reference by maximizing the count of matching pixels. Then the seal overlay metric is computed for the reference and the target. If the overlay metric of a target seal is below a predetermined limit for the similarity to the genuine, then the target is classified as a forged seal. To further reduce the misclassification rate, the seal overlay metric is adjusted by the filling rate, which reflects the quality of inked pattern of the target seal. Experiment results demonstrate that the proposed method can detect elaborate seal impressions created by advanced forgery techniques such as lithography and computer-aided manufacturing. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  14. An Analysis Of The Industrial Forging Process Of Flange In Order To Reduce The Weight Of The Input Material

    Directory of Open Access Journals (Sweden)

    Gronostajski Z.

    2015-06-01

    Full Text Available This paper presents an analysis of the industrial process of hot forging a flange. The authors developed several thermomechanical models of the forging process for which they carried out computer simulations using the MSC.Marc 2013 software. In the Jawor Forge flanges with a neck are manufactured by hot forging in crank presses with a maximum load of 25 MN. The input material, in the form of a square bar, is heated up to a temperature of 1150°C and then formed in three operations: upsetting, preliminary die forging and finishing die forging. The main aim of the studies and the numerical analyses, in which the geometry of the tools would be modified, was to maximally reduce the amount of the input material taking into account the capabilities of the Jawor Forge, and consequently to significantly reduce the production costs. Besides the Forge’s equipment resources, the main constraint for modifications was the flange-with-neck forging standard which explicitely defines the tolerances for this element. The studies, which included numerical modelling, infrared measurements and technological tests, consisted in changing the geometry of the tools and that of the forging preform. As a result, the optimum direction for modifications aimed at reducing the mass of the input material was determined. The best of the solutions, making it possible to produce a correct forging in the Jawor Forge operating conditions, were adopted whereby the weight of the preform was reduced by 6.11%. Currently research is underway aimed at the application of the proposed and verified modifications to other flange forgings.

  15. An Analysis Of The Industrial Forging Process Of Flange In Order To Reduce The Weight Of The Input Material

    OpenAIRE

    Gronostajski Z.; Hawryluk M.; Kaszuba M.; Misiun G.; Niechajowicz A.; Polak S.; Pawełczyk M.

    2015-01-01

    This paper presents an analysis of the industrial process of hot forging a flange. The authors developed several thermomechanical models of the forging process for which they carried out computer simulations using the MSC.Marc 2013 software. In the Jawor Forge flanges with a neck are manufactured by hot forging in crank presses with a maximum load of 25 MN. The input material, in the form of a square bar, is heated up to a temperature of 1150°C and then formed in three operations: upsetting, ...

  16. In a dynamic lifting task, the relationship between cross-sectional abdominal muscle thickness and the corresponding muscle activity is affected by the combined use of a weightlifting belt and the Valsalva maneuver.

    Science.gov (United States)

    Blanchard, Trevor W; Smith, Camille; Grenier, Sylvain G

    2016-06-01

    It has been shown that under isometric conditions, as the activity of the abdominal muscles increases, the thicknesses of the muscles also increase. The purpose of this experiment was to determine whether change in muscle thickness could be used as a measure of muscle activity during a deadlift as well as determining the effect of a weightlifting belt and/or the Valsalva maneuver on the muscle thicknesses. The Transversus Abdominis (TrA) and Internal Obliques (IO) muscles were analyzed at rest and during a deadlift. Muscle thickness was measured using ultrasound imaging and muscle activity was simultaneously recorded using electromyography. Each subject performed deadlift under normal conditions, while performing the Valsalva maneuver, while wearing a weightlifting belt and while both utilizing the belt and the Valsalva maneuver. There was no relationship between change in muscle thickness and muscle activity for both the TrA and IO (R(2)abdominal muscle thickness whereas the belt limited muscle expansion; each with an increase in activity. These results indicate that ultrasound cannot be used to measure muscle activity for a deadlift and that the belt affects how the IO and TrA function together.

  17. Strain-induced grain growth of cryomilled nanocrystalline Al in trimodal composites during forging

    Energy Technology Data Exchange (ETDEWEB)

    Yao, B. [Advanced Materials Processing and Analysis Center, and Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States); Simkin, B.; Majumdar, B. [Materials and Metallurgical Engineering Department, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Smith, C.; Bergh, M. van den [DWA Aluminum Composites, Chatsworth, CA 91311 (United States); Cho, K. [Weapons and Materials Research Directorate, U.S. Army Research Laboratory, Aberdeen Proving Ground, MD 21005 (United States); Sohn, Y.H., E-mail: Yongho.Sohn@ucf.edu [Advanced Materials Processing and Analysis Center, and Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States)

    2012-02-28

    Highlights: Black-Right-Pointing-Pointer Grain growth of cryomilled nanocrystalline aluminum during hot forging. Black-Right-Pointing-Pointer Use of hollow cone dark field imaging technique in TEM for grain size measurement. Black-Right-Pointing-Pointer Grain growth model of strain, strain rate and temperature for forging optimization. - Abstract: Grain growth of nanocrystalline aluminum ({sup nc}Al) in trimodal Al metal-matrix-composites (MMCs) during hot forging was investigated. The {sup nc}Al phase formed through cryomilling of inert gas-atomized powders in liquid nitrogen has an average grain size down to 21 nm, exhibits excellent thermal stability. However, substantial grain growth of {sup nc}Al up to 63 nm was observed when the Al MMCs were thermo-mechanically processed even at relatively low temperatures. Grain growth of the cryomilled {sup nc}Al phase in trimodal Al MMCs after hot forging was documented with respect to temperature ranging from 175 Degree-Sign C to 287 Degree-Sign C, true strain ranging from 0.4 to 1.35 and strain rate ranging from 0.1 to 0.5 s{sup -1}. Hollow cone dark field imaging technique was employed to provide statistically confident measurements of {sup nc}Al grain size that ranged from 21 to 63 nm. An increase in forging temperature and an increase in true strain were correlated with an increase in grain size of {sup nc}Al. Results were correlated to devise a phenomenological grain growth model for forging that takes strain, strain rate and temperature into consideration. Activation energy for the grain growth during thermo-mechanical hot-forging was determined to be 35 kJ/mol, approximately a quarter of activation energy for bulk diffusion of Al and a half of activation energy for static recrystallization.

  18. Optimization and Mechanical Accuracy Reliability of a New Type of Forging Manipulator

    Institute of Scientific and Technical Information of China (English)

    CHEN Kang; MA Chunxiang; ZHENG Maoqi; GAO Feng

    2015-01-01

    Researches on forging manipulator have enormous influence on the development of the forging industry and national economy. Clamp device and lifting mechanism are the core parts of forging manipulator, and have been studied for longer time. However, the optimization and mechanical accuracy reliability of them are less analyzed. Based on General Function(GF) set and parallel mechanism theory, proper configuration of 10t forging manipulator is selected firstly. A new type of forging manipulator driven by cylinders is proposed. After solved mechanical analysis of manipulator’s core mechanisms, expressions of force of cylinders are carried out. In order to achieve smaller force afforded by cylinders and better mechanical characteristics, some particular sizes of core mechanisms are optimized intuitively through the combined use of the genetic algorithms(GA) and GUI interface in MATLAB. Comparing with the original mechanisms, optimized clamp saves at least 8 percent efforts and optimized lifting mechanism 20 percent under maximum working condition. Finally, considering the existed manufacture error of components, mechanical accuracy reliability of optimized clamp, lifting mechanism and whole manipulator are demonstrated respectively based on fuzzy reliability theory. Obtained results show that the accuracy reliability of optimized clamp is bigger than 0.991 and that of optimized lifting mechanism is 0.995. To the whole manipulator under maximum working condition, that value exceeds 0.986 4, which means that optimized manipulator has high motion accuracy and is reliable. A new intuitive method is created to optimize forging manipulator sizes efficiently and more practical theory is utilized to analyze mechanical accuracy reliability of forging manipulator precisely.

  19. Making randomised trials more efficient: report of the first meeting to discuss the Trial Forge platform.

    Science.gov (United States)

    Treweek, Shaun; Altman, Doug G; Bower, Peter; Campbell, Marion; Chalmers, Iain; Cotton, Seonaidh; Craig, Peter; Crosby, David; Davidson, Peter; Devane, Declan; Duley, Lelia; Dunn, Janet; Elbourne, Diana; Farrell, Barbara; Gamble, Carrol; Gillies, Katie; Hood, Kerry; Lang, Trudie; Littleford, Roberta; Loudon, Kirsty; McDonald, Alison; McPherson, Gladys; Nelson, Annmarie; Norrie, John; Ramsay, Craig; Sandercock, Peter; Shanahan, Daniel R; Summerskill, William; Sydes, Matt; Williamson, Paula; Clarke, Mike

    2015-06-05

    Randomised trials are at the heart of evidence-based healthcare, but the methods and infrastructure for conducting these sometimes complex studies are largely evidence free. Trial Forge ( www.trialforge.org ) is an initiative that aims to increase the evidence base for trial decision making and, in doing so, to improve trial efficiency.This paper summarises a one-day workshop held in Edinburgh on 10 July 2014 to discuss Trial Forge and how to advance this initiative. We first outline the problem of inefficiency in randomised trials and go on to describe Trial Forge. We present participants' views on the processes in the life of a randomised trial that should be covered by Trial Forge.General support existed at the workshop for the Trial Forge approach to increase the evidence base for making randomised trial decisions and for improving trial efficiency. Agreed upon key processes included choosing the right research question; logistical planning for delivery, training of staff, recruitment, and retention; data management and dissemination; and close down. The process of linking to existing initiatives where possible was considered crucial. Trial Forge will not be a guideline or a checklist but a 'go to' website for research on randomised trials methods, with a linked programme of applied methodology research, coupled to an effective evidence-dissemination process. Moreover, it will support an informal network of interested trialists who meet virtually (online) and occasionally in person to build capacity and knowledge in the design and conduct of efficient randomised trials.Some of the resources invested in randomised trials are wasted because of limited evidence upon which to base many aspects of design, conduct, analysis, and reporting of clinical trials. Trial Forge will help to address this lack of evidence.

  20. The estimated GFR, but not the stage of diabetic nephropathy graded by the urinary albumin excretion, is associated with the carotid intima-media thickness in patients with type 2 diabetes mellitus: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Ishida Hidenori

    2010-05-01

    Full Text Available Abstract Background To study the relationship between the intima-media thickness (IMT of the carotid artery and the stage of chronic kidney disease (CKD based on the estimated glomerular filtration rate (eGFR and diabetic nephropathy graded by the urinary albumin excretion (UAE in the patients with type 2 diabetes mellitus. Methods A cross-sectional study was performed in 338 patients with type 2 diabetes mellitus. The carotid IMT was measured using an ultrasonographic examination. Results The mean carotid IMT was 1.06 ± 0.27 mm, and 42% of the subjects showed IMT thickening (≥ 1.1 mm. Cerebrovascular disease and coronary heart disease were frequent in the patients with IMT thickening. The carotid IMT elevated significantly with the stage progression of CKD (0.87 ± 0.19 mm in stage 1, 1.02 ± 0.26 mm in stage 2, 1.11 ± 0.26 mm in stage 3, and 1.11 ± 0.27 mm in stage 4+5. However, the IMT was not significantly different among the various stages of diabetic nephropathy. The IMT was significantly greater in the diabetic patients with hypertension compared to those without hypertension. The IMT positively correlated with the age, the duration of diabetes mellitus, and the brachial-ankle pulse wave velocities (baPWV, and negatively correlated with the eGFR. In a stepwise multivariate regression analysis, the eGFR and the baPWV were independently associated with the carotid IMT. Conclusions Our study is the first report showing a relationship between the carotid IMT and the renal parameters including eGFR and the stages of diabetic nephropathy with a confirmed association between the IMT and diabetic macroangiopathy. Our study further confirms the importance of intensive examinations for the early detection of atherosclerosis and positive treatments for hypertension, dyslipidaemia, obesity, as well as hyperglycaemia are necessary when a reduced eGFR is found in diabetic patients.

  1. Tensile test of dumbbell-shaped specimen in thickness direction

    Science.gov (United States)

    Iizuka, Takashi

    2016-10-01

    Sheet metal forming is widely used in manufacturing shops, and evaluation of forming limit for sheet metal is important. However, specimen shape influences on the fracture of the sheet metal. As one of methods to decrease these effects, an uniaxial tensile test using specimen dumbbell-shaped in thickness direction had been examined using FEM analysis. In this study, actually specimen dumbbell-shaped in thickness direction was fabricated using a new incremental sheet forging method, and uniaxial tensile test was conducted. Load-stroke diagram, fracture morphologies, stress-strain curves and shape after fracture were investigated, and effects of specimen shape were considered. Elongation was larger as using specimen dumbbell-shaped in the width direction. Stress-strain curves until necking occurred were less influenced by specimen shape. However, yield stress decreased and local elongation increased as using specimen dumbbell-shaped in the width direction. The reasons why these tendencies showed were considered in the view of specimen shapes.

  2. Correlations between the cross-sectional area and moment arm length of the erector spinae muscle and the thickness of the psoas major muscle as measured by MRI and the body mass index in lumbar degenerative kyphosis patients

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun; Lee, Sang Jin; Lee, Sang Ho [Busan Wooridul Hospital, Busan (Korea, Republic of)

    2006-03-15

    Lumbar degenerative kyphosis (LDK) is a subgroup of the flatback syndrome, which is a condition caused by spinal degeneration. LDK is reported to be the most frequent cause of lumbar spine deformity in the farming districts of the 'oriental' countries. We investigated the relationship between the cross-sectional area (CSA) and the moment arm length (MAL) of the erector spinae muscle and the thickness of the psoas major muscle (PT) and the body mass index (BMI) by performing statistical analysis, and we tried to show the crucial role of these variables for diagnosing LDK. From July 2004 to April 2005, we retrospectively reviewed 17 LDK patients who had undergone anterior lumbar interbody fusion (ALIF) with posterior stabilization. We measured both the CSA and MAL on the transverse cross-sectional MR image of the trunk at the fourth to fifth vertebrae (L4/5). The MAL was defined as the anterior-posterior distance between the center of the erector spinae muscle and that of the vertebral body. A comparative study was undertaken between the LDK group and the matched (according to age and gender) control group with regard to the CSA, MAL, PT and BMI. The 17 LDK patients were all females [age: 62.5 {+-} 4.93 years, height: 157 {+-} 6.19 cm, weight: 55.59 {+-} 4.7 kg, and BMI: 22.58 {+-} 2.08 kg/m{sup 2}]. The control group patients were all female [age: 63.6 {+-} 2.27 years, height: 156 {+-} 5.05 cm, weight: 59.65 {+-} 7.39 kg and BMI: 24.38 {+-} 2.94 kg/m{sup 2}]. Spearman's rho indicated a positive association between the CSA and BMI (rho = 0.49, {rho} = 0.046), between the MAL and BMI (rho = 0.808, {rho} = 0.000) and between the CSA and PT (rho = 0.566, {rho} = 0.018) in the LDK patients. In terms of the CSA versus MAL, there was a positive association in both groups (rho = 0.67, {rho} = 0.000, MAL = 0.023CSA + 5.454 in the LDK group; rho = 0.564, {rho} 0.018, MAL = 0.02CSA + 5.832 in the control group with using linear regression analysis). Independent

  3. Structural changes of radial forging die surface during service under thermo-mechanical fatigue

    Energy Technology Data Exchange (ETDEWEB)

    Nematzadeh, Fardin [Materials and Energy Research Center, Tehran (Iran, Islamic Republic of); Akbarpour, Mohammad Reza, E-mail: mreza.akbarpour@gmail.com [Materials and Energy Research Center, Tehran (Iran, Islamic Republic of); Kokabi, Amir Hosein; Sadrnezhaad, Seyed Khatiboleslam [Department of Materials Science and Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2009-12-15

    Radial forging is one of the modern open die forging techniques and has a wide application in producing machine parts. During operation at high temperatures, severe temperature change associated with mechanical loads and the resultant wearing of the die surface lead to intense variation in strain on the die surface. Therefore, under this operating condition, thermo-mechanical fatigue (TMF) occurs on the surface of the radial forging die. TMF decreases the life of the die severely. In the present research, different layers were deposited on a 1.2714 steel die by SMAW and GTAW, with a weld wire of UDIMET 520. The microstructure of the radial forging die surface was investigated during welding and service using an optical microscope and scanning electron microscope. The results revealed that, after welding, the structure of the radial forging die surface includes the {gamma} matrix with a homogeneous distribution of fine semi-spherical carbides. The weld structure consisted mostly of columnar dendrites with low grain boundaries. Also, microstructural investigation of the die surface during operation showed that the weld structure of the die surface has remained without any considerable change. Only dendrites were deformed and broken. Moreover, grain boundaries of the dendrites were revealed during service.

  4. New design of process for cold forging to improve multi-stage gas fitting

    Directory of Open Access Journals (Sweden)

    Han-Sung Huang

    2016-04-01

    Full Text Available This work develops a process that solves the problem of the formation of cracks inside forged gas fittings in the cold forging process that arises from poor forging process design. DEFORM-3D forming software was utilized, and macroscopic experiments with optical microscopy and scanning electron microscopy were conducted to investigate the processed structures and the distribution therein of metal flow lines, and to find the internal micro-cracks to determine whether the cold forging process is reasonable. Analytical results herein demonstrate that the stress and strain inside the gas fitting can be elucidated using metal forming software. Together with experimental results, they demonstrate that a concentration of stress damages the workpiece in the forming process. Moreover, as metal flow lines become narrower, the workpiece becomes more easily damaged. Consequently, the improved cold forging process that is described in this work should be utilized to reduce the occurrence of fine cracks and defects. Planning for proper die design and production, increasing the quality of products, and reducing the number of defective products promote industrial competitiveness.

  5. Non-isothermal FEM analyses of large-strain back extrusion forging

    Energy Technology Data Exchange (ETDEWEB)

    Flower, E.C.; Hallquist, J.O.; Shapiro, A.B.

    1986-06-19

    Back extrusion forging is a complex metal forming operation dominated by large-strain, non-isothermal deformation. NIKE2D, a fully vectorized implicit finite-element program developed at Lawrence Livermore National Laboratory, was applied to a two-stage isothermal back extrusion forging process. Modeling of the forging process required special features in the FEM code such as friction and interactive rezoning that allows for remeshing of the distorted mesh while maintaining a complete history of all the state variables. To model conditions of the non-isothermal forging process required implementing TOPAZ2D, our LLNL-developed two-dimensional implicit finite element code for heat conduction analysis, as a subroutine into NIKE2D. The fully coupled version maintains all the original features of both codes and can account for the contribution of heat generation during plastic deformation. NIKE/TOPAZ-2D was applied to the piercing operation of the back extrusion forging process. The thermal deformation history of the die, punch, and workpiece and the effective plastic strains were calculated.

  6. Microstructure Evolution of Multi-Heat Forging and Numerical Simulation for 316LN Steel

    Directory of Open Access Journals (Sweden)

    Duan Xing-Wang

    2014-02-01

    Full Text Available Microstructure evolution has been studied by multi-heat forging experiments and numerical simulation in order to determine the reasonable forging technology of 316 LN steel. The microstructure evolution models were obtained by hot compressive tests and heat treatment tests of 316 LN steels. The one-heat and three-heat upsetting experiments were carried on. Meanwhile, the corresponding numerical simulations were performed. The results show that, the grain uniformity of three-heat upsetting is much better that of one-heat upsetting. The average grain size of three-heat upsetting is smaller than that of one-heat upsetting. So, the forging technology of multi-heat and little deformation should be adopted for 316 LN steel forging. By comparing experimental average grain sizes with simulated average grain sizes for three-heat upsetting, it is found that the simulated values are in agreement with experimental values, which shows that the numerical simulation can be employed to predict the forging microstructure evolution of 316 LN steel.

  7. Manufacturing of Nanostructured Rings from Previously ECAE-Processed AA5083 Alloy by Isothermal Forging

    Directory of Open Access Journals (Sweden)

    C. J. Luis

    2013-01-01

    Full Text Available The manufacturing of a functional hollow mechanical element or ring of the AA5083 alloy previously equal channel angular extrusion (ECAE processed, which presents a submicrometric microstructure, is dealt with. For this purpose, the design of two isothermal forging dies (preform and final shape is carried out using the design of experiments (DOE methodology. Moreover, after manufacturing the dies and carrying out tests so as to achieve real rings, the mechanical properties of these rings are analysed as well as their microstructure. Furthermore, a comparison between the different forged rings is made from ECAE-processed material subjected to different heat treatments, previous to the forging stage. On the other hand, the ring forging process is modelled through the use of finite element simulation in order to improve the die design and to study the force required for the isothermal forging, the damage value, and the strain the material predeformed by ECAE has undergone. With this present research work, it is intended to improve the knowledge about the mechanical properties of nanostructured material and the applicability of this material to industrial processes that allow the manufacturing of functional parts.

  8. Modeling microstructure evolution in the delta process forging of superalloy IN718 turbine discs

    Science.gov (United States)

    Zhang, Haiyan; Zhang, Shihong; Cheng, Ming; Zhao, Zhong

    2013-05-01

    The microstructure development in the Delta Process (DP) forging of Superalloy IN718 turbine discs were predicted using the combined approach of axisymmetric finite element simulation and modeling for the dynamic recrystallization and grain growth. In order to establish the deformation constitutive equation and dynamic recrystallization models for the DP process of Superalloy IN718, the isothermal compression tests were carried out in the temperature range 950 to 1010 °C and strain rates range 0.001 to0.1s-1. Moreover, the isothermal heat treatment tests after hot deformation were conducted in the temperature range 950 to 1040°C to generate the grain growth model. The experimental results indicated the existence of the δ phase could make the activation energy of deformation increase. Furthermore, the existence of the δ phase could stimulate the occurrence of dynamic recrystallization, and the grain growth was restrained due to the pinning effect of δ phase. The predicted grain size and its distribution in the DP forging of Superalloy IN718 turbine discs were compared with the actual microstructures deformed by the hot die forging. It was found that the forging with uniform fine grains could be obtained by the application of DP process to the forging of the turbine disk, in which the alloy was pre-precipitated δ phase after the baiting in the original process.

  9. Forging of Naval Brass (ASTM B16) - Finite Element Analysis using Ls Dyna

    Science.gov (United States)

    Subha Sankari, T.; Sangavi, S.; Paneerselvam, T.; Venkatraman, R.; Venkatesan, M.

    2016-09-01

    Forging is one of the important manufacturing process in which products like connecting rod, transmission shaft, clutch hubs and gears are produced. Finite element analysis (FEA) in forming techniques is of recent interest for the optimal design and determination of right manufacturing forming process. The data from the numerical results can help in providing the information for selecting the ideal process conditions. Thus aside from experimental values, simulation by the finite element analysis software's such as LS DYNA can be used for the analysis of strain distribution in forging processes. In the present work, Finite element simulation of open die forging of naval brass (ASTM B16) is done at an optimal temperature. An advanced multi physics simulation software package by the Livermore software technology cooperation LSTC - LS DYNA is utilized for the simulation of forging process. For the forging validation, experiment is conducted with a cylindrical billet having height 45 mm and diameter of 40mm. The numerical results are compared with that of experimental results carried out at the same temperature and dimensions for validation. The distribution of strain is analyzed. Energy analysis due to impact load is detailed. The simulation results are found to be in good agreement with the experimental results.

  10. Filling Rules of Bevel Gears in the Closed-die Cold Forging

    Institute of Scientific and Technical Information of China (English)

    Huamin LIU; Liangju HUANG; Shenhua YANG; Shihong ZHANG

    2005-01-01

    The closed-died cold forging technology of the bevel gears used in Jada car was investigated. With the analysis of the strain field and velocity field of the plastic deformation and the endured forces of the dies, the filling rules forthe metal were analyzed by the elastic-plastic finite element method (FEM). The results show that there is a great difference among closed-die cold forging, extrusion and forging, as far as the metal flowing is concerned. The outer addendum cannot be filled completely in the closed-die cold forging of the bevel gears, and the round angle will be formed. But it does not influence the application of the bevel gears. At the beginning, the rigid area is formed in the cavity of the lower die. And then it will move upwards to supply the metal for the gear filling. For the closed-die cold forging of the bevel gears, the force acting on the upper die and the lower die is significantly different.

  11. Effect of Forging on Microstructure, Texture, and Uniaxial Properties of Cast AZ31B Alloy

    Science.gov (United States)

    Toscano, D.; Shaha, S. K.; Behravesh, B.; Jahed, H.; Williams, B.

    2017-07-01

    The effect of open-die hot forging on cast AZ31B magnesium alloy was investigated in terms of the evolution of microstructure, texture, and mechanical properties. A refined microstructure with strong basal texture was developed in forged material. A significant increase in tensile yield and ultimate strengths by 143 and 23%, respectively, was determined as well. When tested in compression at room temperature, the forged alloy displayed significant in-plane asymmetry and unchanged yield strength compared to the cast alloy owing to the activation of 10\\bar{1}2} Microstructure and texture analysis of the fracture samples confirmed that the deformation of the forged samples was dominated by slip during tension and twin in compression. In comparison, both slip and twin were observed in the cast samples for similar testing conditions. The increase in strength of forging was attributed to the refinement of grains and the formation of strong basal texture, which activated the non-basal slip on the prismatic and pyramidal slip systems instead of extension twin.

  12. 基于Forge2D/3D的阀体胎模锻模拟分析%Simulation of Die-forging for Valve Based on Forge 2D/3D

    Institute of Scientific and Technical Information of China (English)

    康海鹏

    2012-01-01

    采用Forge 2D/3D有限元分析模拟软件,设计阀体胎模和坯料;经过模拟分析了成型过程中坯料的温度变化、整体的应力、应变、金属的流动趋势和流线分布等;通过生产验证了胎模和坯料设计的合理性和工艺的可行性.%The die and billet of a valve was designed by Forge 2D/3D software. The temperature, stress, strain, and metal flow trend of billet during the simulation was analyzed; the rationality of die, billet design and feasibility of process was validated by production.

  13. B超检测子宫下段厚度对剖宫产术后患者再妊娠阴道分娩的意义%Significance of B ultrasound measurement of lower uterine segment thickness in vaginal birth after cesarean section

    Institute of Scientific and Technical Information of China (English)

    梅琳琳; 王雅莉; 张国梅; 刘文枝; 田晓娜

    2011-01-01

    Objective To investigate the the significance of B ultrasound measurement of the lower uterine segment(LUS) thickness in vaginal birth after cesarean section(VBAC). Methods Using B ultrasound measure the LUS thickness in 88 women with previous caesarean section, the outcome is contrasted with delivery and operation. Results A sonographic LUS thickness of ≥2mm was allowed to vaginal birth. Conclusions With B ultrasound measurement of the LUS thickness, women with previous caesarean section can get favorable guidance, also can predict aura uterine rupture.%目的 探讨应用B超检测妊娠晚期子宫下段厚度对剖宫产术后阴道分娩的指导意义.方法 应用B超检测88例有剖宫产史孕妇的子宫下段厚度,并与分娩及手术结果对比.结果 B超检测妊娠晚期子宫下段厚度≥2mm者可行阴道试产.结论 应用B超检测子宫下段厚度对剖宫产术后妊娠患者分娩方式的选择提供有利的指导,并能预测先兆子宫破裂的发生.

  14. Three-Dimensional Reconstruction Method of Large Axisymmetric Forge Workpieces%大型回转类锻件的三维重建方法

    Institute of Scientific and Technical Information of China (English)

    林洪彬; 刘彬; 张玉存

    2011-01-01

    A single-image-based three-dimensional (3D) reconstruction method of an axisymmetric forge piece is proposed. The imaged circular points are solved from two paralell cross sections extracted from the image. Combining with the epipolar constraint, the 3-parameter constraint equations of the imaged absolute conic are established and the intrinsic parameters are solved. The imaged meridian and latitude of the surface of the axisymmetric forge piece are extracted based on the planner projection characteristics between two paralell cross sections. Then 3D shape of the axisymmetric forge piece is reconstructed based on the corrected imaged meridian. The visible region of the cross section is computed based on Laguerre formula, and an equal-arc sampling strategy is proposed based on the extracted imaged meridian, solving the inconsistent resolution problem of conventional texture extraction algorithm. Experimental results indicate that the large axisymmetric forge piece can be reconstructed with its own geometrical constraint from sinlge image without any auxiliary calibration equipment and the reconstructed shape and effective texture can be obtained.%提出一种基于单幅图像的回转类锻件三维重建方法.利用图像中提取的锻件截面椭圆求解圆环点图像,并结合极线约束建立绝对二次曲线像的三参数约束方程,进而求取相机的内参数矩阵.利用平行截面椭圆间的平面投影特性,进行回转体表面经线和纬线的求解,进而通过对经线进行校正实现被测锻件形状的三维重建.利用拉盖尔(Laguerre)公式进行截面椭圆可见区域求解,提出了一种等弧长纹理采样方法,解决了传统纹理提取中纹理分辨率不一致的问题.实验结果表明,在只利用被测对象自身几何约束,不借助辅助标定设备条件下,形状重建及纹理映射结果较为有效.

  15. Comparison between hobbed and precision forged helical gears for automobile manual transaxle - on the prospect of form, precision, material specification and production cost

    Energy Technology Data Exchange (ETDEWEB)

    Ooka, M.; Kawasaki, Y.; Hoguchi, T.; Tsujimoto, H.; Yamazaki, S.; Yoshinaga, M. [O-oka Co., Toyota (Japan); Moriwaki, I. [Kyoto Inst. of Tech. (Japan); Kagaya, C. [Chubu Univ., Kasugai (Japan)

    2005-07-01

    This paper describes the comparison between hobbed and forged helical gears in terms of precision, deformation of heat-treatment, material specification and production cost. With the results the forged ones are superior to hobbed ones. (orig.)

  16. Numerical simulation of the dynamic recrystallization behaviour in hot precision forging helical gears

    Directory of Open Access Journals (Sweden)

    Feng Wei

    2015-01-01

    Full Text Available In hot precision forging helical gears, the dynamic recrystallization phenomena will occur, which affect the microstructure of the formed part and in turn decide their mechanical properties. To investigate the effect of deformation temperature on the dynamic recrystallization in hot precision forging helical gears, a three dimensional (3D finite element (FE model was created by coupling the thermo-mechanical model with the microstructure evolution model developed based on the hot compressive experimental data of 20CrMnTiH steel. The hot precision forging process was simulated and the effect laws of the deformation temperature on the microstructure evolution the formed part were investigated. The results show that the dynamic recrystallization volume fraction and the average grain sizes increased with the increasing deformation temperature and the higher deformation temperature is beneficial to dynamic recrystallization and grain refinement.

  17. Modelling the void deformation and closure by hot forging of ingot castings

    DEFF Research Database (Denmark)

    Christiansen, Peter; Hattel, Jesper Henri; Kotas, Petr;

    2012-01-01

    After solidification and cooling cast ingots contain voids due to improper feeding and volume shrinkage. Such voids are normally unwanted, so besides of forming the ingot to the desired shape, one of the purposes of the post processing of the ingot by hot forging is to close such voids by mechani......After solidification and cooling cast ingots contain voids due to improper feeding and volume shrinkage. Such voids are normally unwanted, so besides of forming the ingot to the desired shape, one of the purposes of the post processing of the ingot by hot forging is to close such voids...... and focuses on how the voids deform depending on their size and distribution in the ingot as well ashow the forging forces are applied....

  18. Analysis Of Potentiometric Methods Used For Crack Detection In Forging Tools

    Science.gov (United States)

    Pilc, Jozef; Drbúl, Mário; Stančeková, Dana; Varga, Daniel; Martinček, Juraj; Kuždák, Viktor

    2015-12-01

    Increased use of forging tools in mass production causes their increased wear and creates pressure to design more efficient renovation process. Renovation is complicated because of the identification of cracks expanding from the surface to the core material. Given that the production of forging tools is expensive, caused by the cost of tool steels and the thermo-chemical treatment, it is important to design forging tool with its easy renovation in mind. It is important to choose the right renovation technology, which will be able to restore the instrument to its original state while maintaining financial rentability. Choosing the right technology is difficult because of nitrided and heat-treated surface for high hardness and wear resistance. Article discusses the use of non-destructive method of detecting cracks taking into account the size of the cracks formed during working process.

  19. Application of geometric midline yield criterion to analysis of three-dimensional forging

    Institute of Scientific and Technical Information of China (English)

    ZHAO De-wen; WANG Gen-ji; LIU Xiang-hua; WANG Guo-dong

    2008-01-01

    A kinematically admissible continuous velocity field was proposed for the analysis of three-dimensional forging. The linear yield criterion expressed by geometric midline of error triangle between Tresca and Twin shear stress yield loci on the π-plane, called GM yield criterion for short, was firstly applied to analysis of the velocity field for the forging. The analytical solution of the forging force with the effects of external zone and bulging parameter is obtained by strain rate inner product. Compression tests of pure lead are performed to compare the calculated results with the measured ones. The results show that the calculated total pressures are higher than the measured ones whilst the relative error is no more than 9.5%. It is implied that the velocity field is reasonable and the geometric midline yield criterion is available. The solution is still an upper-bound one.

  20. Design of relief-cavity in closed-precision forging of gears

    Institute of Scientific and Technical Information of China (English)

    左斌; 王宝雨; 李智; 郑明男; 朱小星

    2015-01-01

    To reduce the difficulty of material filling into the top region of tooth in hot precision forging of gears using the alternative die designs, relief-cavity designs in different sizes were performed on the top of die tooth. The influences of the conventional process and relief-cavity designs on corner filling, workpiece stress, die stress, forming load and material utilization were examined. Finite element simulation for tooth forming, die stress and forming load using the four designs was performed. The material utilization was further considered, and the optimal design was determined. The tooth form and forming load in forging trials ensured the validity of FE simulation. Tooth accuracy was inspected by video measuring machine (VMM), which shows the hot forged accuracy achieves the level of rough machining of gear teeth. The effects of friction on mode of metal flow and strain distribution were also discussed.

  1. A two-step superplastic forging forming of semi-continuously cast AZ70 magnesium alloy

    Directory of Open Access Journals (Sweden)

    Pan Wang

    2015-03-01

    Full Text Available A two-step technology combined forging with superplastic forming has been developed to enhance the forgeability of semi-continuously cast AZ70 magnesium alloy and realize the application of the as-cast magnesium alloy in large deformation bullet shell. In the first step, fine-grained microstructure preforms that are suitable for superplastic forming were obtained by reasonably designing the size of the initial blanks with the specific height-to-diameter ratio, upsetting the blanks and subsequent annealing. In the second step, the heat treated preforms were forged into the end products at the superplastic conditions. The end products exhibit high quality surface and satisfied microstructure. Consequently, this forming technology that not only avoids complicating the material preparation but also utilizes higher strain rate superplastic provides a near net-shaped novel method on magnesium forging forming technology using as-cast billet.

  2. Large size austenitic stainless steel forgings for nuclear and cryogenic application - development, manufacturing and properties

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, Keizo; Suzuki, Komei; Sato, Ikuo; Murai, Etuso (Japan Steel Works Ltd., Muroran Plant, Hokkaido (Japan))

    1992-01-01

    The high quality one-piece large austenetic stainless steel forgings are required in the several components such as nuclear reactors and run tanks for rocket engine test stand in order to assure the structural integrity and to make it easy to fabricate and inspect the components. When the austenitic stainless steel forgings are increased in size, various problems must be overcome to assure the high quality forgings. The ingot making and hot working play an important role in determining the quality of the products. In such points, the lastest manufacturing techniques such as steel making of large size ingot and hot working to get uniform and fine grains are discussed together with the fundamental data of the material properties. (orig.).

  3. The Simulation and Analysis of the Closed Die Hot Forging Process by A Computer Simulation Method

    Directory of Open Access Journals (Sweden)

    Dipakkumar Gohil

    2012-06-01

    Full Text Available The objective of this research work is to study the variation of various parameters such as stress, strain, temperature, force, etc. during the closed die hot forging process. A computer simulation modeling approach has been adopted to transform the theoretical aspects in to a computer algorithm which would be used to simulate and analyze the closed die hot forging process. For the purpose of process study, the entire deformation process has been divided in to finite number of steps appropriately and then the output values have been computed at each deformation step. The results of simulation have been graphically represented and suitable corrective measures are also recommended, if the simulation results do not agree with the theoretical values. This computer simulation approach would significantly improve the productivity and reduce the energy consumption of the overall process for the components which are manufactured by the closed die forging process and contribute towards the efforts in reducing the global warming.

  4. The effects of thermomechanical history on the microstructure of a nickel-base superalloy during forging

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, S., E-mail: 485354@swansea.ac.uk [College of Engineering, Bay Campus, Swansea University, Swansea SA1 8EN (United Kingdom); Li, W. [Rolls-Royce plc, PO Box 31, Derby DE24 8BJ (United Kingdom); Coleman, M. [College of Engineering, Bay Campus, Swansea University, Swansea SA1 8EN (United Kingdom); Johnston, R., E-mail: r.johnston@swansea.ac.uk [College of Engineering, Bay Campus, Swansea University, Swansea SA1 8EN (United Kingdom)

    2016-06-21

    The effect of thermo-mechanical history on hot compression behaviour and resulting microstructures of a nickel base superalloy is presented. Hot compression tests were carried out on HAYNES® 282® specimens to varying strains from 0.1 to 0.8. Both single pass and multi-pass tests were completed. 60 min inter-pass times were utilized to accurately replicate industrial forging practices. The effect of dynamic, metadynamic and static recrystallization during inter-pass times on flow stress was investigated. The resulting microstructures were analysed using scanning electron, optical microscopy and EBSD to relate grain size and homogeneity with flow stress data. The study showed a negligible difference between multi-pass and single pass tests for strain increments above 0.2. Therefore, when modelling similar low strain and strain rate forging processes in HAYNES® 282®, previous forging steps can be ignored.

  5. Finite element simulation of stretch forging using a mesh condensation method

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In order to reduce the computation time of finite element simulations of stretch forging process,a mesh condensation method is presented and applied to a three-dimensional rigid-viscoplastic finite element program.In this method,a conventional mesh for the whole zone of a workpiece is condensed to a computational mesh for the active deformation zone.Two vital problems are solved,which are automatic construction of the computational mesh and treatment of interfaces between the deformation zone and the rigid zone.The mesh condensation method is compared with conventional finite element method by simulations of a six-bite stretch forging process.Some simulation results including forging load,temperature distribution and effective strain distribution are illustrated.The efficiency and accuracy of this method are verified.

  6. Heuristic algorithm for planning and scheduling of forged pieces heat treatment

    Directory of Open Access Journals (Sweden)

    R. Lenort

    2012-04-01

    Full Text Available The paper presents a heuristic algorithm for planning and scheduling of forged pieces heat treatment which allows maximizing the capacity exploitation of the heat treatment process and the entire forging process. Five Focusing Steps continuous improvement process was selected as a methodological basis for the algorithm design. Its application was supported by simulation experiments performed on a dynamic computer model of the researched process. The experimental work has made it possible to elicit the general rules for planning and scheduling of the heat treatment process of forged pieces which reduce losses caused by equipment conversion and setup times, and which increase the throughput of this process. The HIPO diagram was used to design the algorithm.

  7. Design of Controlled Processing Conditions for Drop Forgings Made of Microalloy Steel Grades for Mining Industry

    Directory of Open Access Journals (Sweden)

    Skubisz P.

    2015-04-01

    Full Text Available Effect of plastic processing and controlled cooling on microstructure and mechanical properties of experimental steel grades with microalloyed with Ti, V and/or Nb, varying in the content of Mo is presented as an offer for mining industry for replacement traditionally heat-treatable hardenability grades. The goal of the work is producing microstructure condition, which after controlled hot forging and direct heat treatment, involving quenching and self-tempering, are meant to provide good combination of mechanical properties, such as TYS 800 MPa, UTS 1050 MPa, elongation to fracture at least A5 15% and/or impact strength at room temperature KCV 60 J/cm2. Hardenability assessment and dilatometric examination allowed formulation of direct heat treatment guidelines, taking into consideration fields of temperature and strain in a typical hot forging process, estimated numerically, with the use of plastometric tests results, as well as the use of unique cooling cycles after forging.

  8. The Investigations of Friction under Die Surface Vibration in Cold Forging Process

    DEFF Research Database (Denmark)

    Jinming, Sha

    is undergoing vibration. In the experiments, die surface orientation, frequency and amplitude of vibration, vibrating wave form and the direction of vibration has been taken into account as the parameters which influence friction behaviour in forging process. The results reveal that friction could be reduced up......The objective of this thesis is to fundamentally study the influence of die surface vibration on friction under low frequency in metal forging processes. The research includes vibrating tool system design for metal forming, theoretical and experimental investigations, and finite element simulations...... on die surface vibration in forging process. After a general introduction to friction mechanisms and friction test techniques in metal forming, the application of ultrasonic vibration in metal forming, the influence of sliding velocity on friction is described. Some earlier investigations...

  9. Development of a 3D Finite Element code for Forging - An overview of the Brite/Euram project EFFORTS

    DEFF Research Database (Denmark)

    Bay, Niels; Andreasen, Jan Lasson; Olsson, David Dam

    2001-01-01

    equations for flow stress in cold as well as hot forging, determination of interface conditions, i.e. friction and heat transfer in cold and hot forging. The developments are validated by physical and numerical modeling and finally verified by analysis of some complex industrial examples....

  10. Multi-objective optimization of gear forging process based on adaptive surrogate meta-models

    Science.gov (United States)

    Meng, Fanjuan; Labergere, Carl; Lafon, Pascal; Daniel, Laurent

    2013-05-01

    In forging industry, net shape or near net shape forging of gears has been the subject of considerable research effort in the last few decades. So in this paper, a multi-objective optimization methodology of net shape gear forging process design has been discussed. The study is mainly done in four parts: building parametric CAD geometry model, simulating the forging process, fitting surrogate meta-models and optimizing the process by using an advanced algorithm. In order to maximally appropriate meta-models of the real response, an adaptive meta-model based design strategy has been applied. This is a continuous process: first, bui Id a preliminary version of the meta-models after the initial simulated calculations; second, improve the accuracy and update the meta-models by adding some new representative samplings. By using this iterative strategy, the number of the initial sample points for real numerical simulations is greatly decreased and the time for the forged gear design is significantly shortened. Finally, an optimal design for an industrial application of a 27-teeth gear forging process was introduced, which includes three optimization variables and two objective functions. A 3D FE nu merical simulation model is used to realize the process and an advanced thermo-elasto-visco-plastic constitutive equation is considered to represent the material behavior. The meta-model applied for this example is kriging and the optimization algorithm is NSGA-II. At last, a relatively better Pareto optimal front (POF) is gotten with gradually improving the obtained surrogate meta-models.

  11. 搅拌摩擦焊中锻压效应的强化与作用%Effect and enhancement of forging action during friction stir welding

    Institute of Scientific and Technical Information of China (English)

    张贵锋; 苏伟; 张军; 张建勋

    2011-01-01

    To visualize the fact that the forging effect can be enhanced by tilting tool during friction stir welding,a novel experimental way,in which a backing plate with predrilled hole was used, was proposed and expected result was obtained. Using a tool without pin and a backing plate with a predrilled hole(Φ4 mm) the friction lap welding of 2 mm thick aluminum sheet was performed under the conditions of tilting tool(3°) and not tilting tool(0°).The length of plasticized aluminum extnlded into predrilled hole within backing plate was 5.3 mm and 2.6 mm at different tilting angle of 3° and 0° ,respectively.The result indicated that the forging effect can be enhanced by tilting tool,the primary loaded body of forging effect should be plasticized material at trading edge of pin (but beneath shoulder) , and the primary loading body of forging effect should be shoulder especially when using smooth pin without thread. Based on the above result,a mathematical relationship between axial forging pressure and tilt angle was proposed. It was derived from the mathematical relationship and comparative result of defect in the two kinds of welds with and without tilt angle that he forging effect has significant contribution to eliminating void defect behind pin due to the enhancement of plastic flow in multi-directions,especially in axial direction of tool.%为直观证明倾斜工具能强化搅拌搭接摩擦焊中的锻压效应之事实,提出了一种新的实验方案(采用预先开有小孔的垫板)并获得了预期效果.采用无针柱状搅拌头与预先开有φ4mm小孔的垫板,分别在有/无倾角的两种情况下进行了2 mm厚薄铝板的搭接搅拌摩擦焊.结果表明,在倾角为3°情况下被挤入垫板小孔内的塑化金属的长度(5.3 mm)远大于无倾角情况下的相应值(2.6 mm).可见,工具的倾斜可导入并强化焊缝中心区的锻压效应;锻压效应的受力体是针后高温软化金属;锻压效应的主要施力体应是肩,

  12. The Development of a Ceramic Mold for Hot-Forging of Micro-Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Christenson, Todd; Garino, Terry

    1999-06-25

    A new mold material has been developed for use in making rare-earth permanent magnet components with precise dimensions in the 10 to 1000 µm range by hot-forging. These molds are made from molds poly(methyl)methacrylate (PMMA) made by deep x-ray lithography (DXRL). An alumina bonded with colloidal silica has been developed for use in these molds. This material can be heated to 950°C without changing dimensions where it develops the strength needed to withstand the hot-fmging conditions (750°C, 100 MPa). In addition, it disintegrates in HF so that parts can be easily removed after forging.

  13. Simulative Testing of Friction and Lubrication in Cold Forging of Steel and Aluminum

    DEFF Research Database (Denmark)

    Ceron, Ermanno; Bay, Niels; Aida, Tetsuo

    2012-01-01

    A new, simulative test of friction and lubrication in cold forging is developed by the authors. The test is based on a backward can extrusion process in which the workpiece rotates relatively to the conical punch. An analytical model is presented determining the friction stress from the measured ...... coating plus MoS2 and single bathe lubrication with PULS and aluminum provided with 6 different lubricant systems. The new test is so severe, that it is possible to break down the best lubrication systems for cold forging of steel and aluminum....

  14. An upper bound solution for closed die sinter forging of hexagonal shapes

    Indian Academy of Sciences (India)

    R K Ranjan; S Kumar

    2004-06-01

    The paper reports on an investigation into the various aspects of closed die cold forging of hexagonal powder preforms, which have been compacted and sintered from atomized powder. It is found that for certain dimensional ratios of the preform, the die pressure is minimum. An attempt has been made determine the die pressures developed during the closed die forging of the hexagonal powder preform by using an upper bound approach. The results so obtained are discussed critically to illustrate the interaction of various process parameters involved and are presented graphically.

  15. Theoretical study on Cold Open Die Forging Process Optimization for Multipass Workability

    Directory of Open Access Journals (Sweden)

    Gaikwad Ajitkumar

    2016-01-01

    Full Text Available Cold Workability limits strength enhancement of austenitic materials through cold deformation. The intrinsic workability is the material characteristic whereas state-of-stress workability is governed by nature of applied stress, strain rate and geometry of deformation zone. For Cold Open Die Forging (CODF, multipass workability is essential. In this work, FEM tool FORGE-3 is used to optimize CODF on hydraulic press by analysis of stress-strain profiles and use of Latham-Cockroft damage criterion. Study recommends optimized process parameters, die combinations and pass-schedules.

  16. Trial Production of Drum Forgings%鼓轮锻件的生产试制

    Institute of Scientific and Technical Information of China (English)

    张广森; 张成霞; 陈国红; 黄冬凤; 刘垒; 丁宝平

    2013-01-01

    The abnormity cylinder forgings with big taper and small height is produced successfully by blanking with top flat anvil and bottom V shaped anvil , which lays the foundation to manufacture nuclear power tapered cylinder forgings.%采用上平、下V型砧制坯,成功生产了锥度大、高度小的异形筒体锻件,为公司在核电锥形筒体锻件生产方面打下了基础。

  17. THE FORMING OF MAGNESIUM ALLOY FORGINGS FOR AIRCRAFT AND AUTOMOTIVE APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Anna Dziubińska

    2016-09-01

    Full Text Available The paper presents the theoretical and technological aspects of forming magnesium alloy parts for aircraft and automotive applications. The main applications of magnesium alloys in the aircraft and automotive industries are discussed. In addition, the forging technology for magnesium alloys is generally described, with a particular emphasis on wrought alloys. A brief outline of the state of the art in the forging of magnesium alloys is given based on a survey of the specialist literature and the results of previous research by the authors.

  18. High speed forging of solid powder discs of large slenderness ratio

    Indian Academy of Sciences (India)

    R K Ranjan; S Kumar

    2004-10-01

    The paper reports an investigation into the forging of a solid powder circular disc with large slenderness ratio (L/D) between two flat dies at high speed. The deformation pattern during the operation is influenced by many factors, which interact with one another in a complex manner. The decisive factors are the interfacial conditions, initial relative density of the preform and the geometry of the preform. An attempt has been made to determine the die pressures developed during such forging, using an upper bound approach. The results so obtained are presented graphically and discussed critically to illustrate the interaction of various process parameters involved.

  19. 超大筒节锻造工艺的优化%Optimization of Forging Process for Large Shell Ring

    Institute of Scientific and Technical Information of China (English)

    施熔刚; 张强升; 姜述杰; 张丽丹

    2013-01-01

    通过设计辅助工具方法及简化锻造工序对原有超大筒节锻件工艺进行改进,将原来锻造6火次出成品的锻造工艺改为4火次出成品,在确保产品质量的同时,有效的降低锻造生产成本,提高锻造生产效率.%The original forging process for large shell ring forging was improved through the methods of designing aid tools and simplifying forging process,that is,the original forging process of 6 fire times was instead of that of 4 fire times.The improved forging process can ensure product quality,reduce production costs and improve production efficiency.

  20. The thickness of glaciers

    Science.gov (United States)

    Faraoni, Valerio; Vokey, Marshall W.

    2015-09-01

    Basic formulae and results of glacier physics appearing in glaciology textbooks can be derived from first principles introduced in algebra-based first year physics courses. We discuss the maximum thickness of alpine glaciers and ice sheets and the relation between maximum thickness and length of an ice sheet. Knowledge of ordinary differential equations allows one to derive also the local ice thickness.

  1. Design and optimization of I-beam precision roll forging process for heavy truck front axle%某重卡前轴工字梁辊锻成形工艺设计及优化

    Institute of Scientific and Technical Information of China (English)

    张黎; 文琍; 夏江梅

    2012-01-01

    The under-filling defect of the I-beam, one of the typical defects on a heavy truck front axle in the precision roll forging process and die forging process was studied Firstly, the design of the precision roll forging process for the I-beam of the front axle was described. Then, the finite element numerical simulation analysis model was established with Deform-3D, and the influence of the thickness on the I-beam in the third step and the friction factor in the third and fourth step on filling percent of the die cavity was analyzed. Lastly, optimization for the precision roll forging process of the heavy truck front axle was finished. The optimized simulation results show that the I-beam forms well and can be filled fully to meet the requirements of design drawings.%针对某重卡前轴成形辊锻-模锻复合工艺中的典型缺陷——工字梁部位充不满展开研究.介绍了重卡前轴工字梁在辊锻成形工艺中各道次的孔型设计,通过Defoem-3D建立了有限元数值模拟分析模型,研究了第3道次预辊锻成形中工字梁壁厚和第3、4道次中摩擦因子对模具型腔填充率的影响规律,最后完成了重卡前轴工字梁在辊锻成形中的优化设计.优化后的模拟结果表明,工字梁成形良好、填充饱满,满足图纸设计要求.

  2. Characterization of Cracking and Crack Growth Properties of the C5A Aircraft Tie-Box Forging

    Science.gov (United States)

    Piascik, Robert S.; Smith, Stephen W.; Newman, John A.; Willard, Scott A.

    2003-01-01

    Detailed destructive examinations were conducted to characterize the integrity and material properties of two aluminum alloy (7075-T6) horizontal stabilizer tie box forgings removed.from US. Air Force C5A and C5B transport aircraft. The C5B tie box forging was,found to contain no evidence of cracking. Thirteen cracks were found in the CSA,forging. All but one of the cracks observed in the C5A component were located along the top cap region (one crack was located in the bottom cap region). The cracks in the C5A component initiated at fastener holes and propagated along a highly tunneled intergranular crack path. The tunneled crack growth configuration is a likelv result of surface compressive stress produced during peening of the .forging suijace. The tie box forging ,fatigue crack growth, fracture and stress corrosion cracking (SCC) properties were characterized. Reported herein are the results of laboratory air ,fatigue crack growth tests and 95% relative humidity SCC tests conducted using specimens machined from the C5A ,forging. SCC test results revealed that the C5A ,forging material was susceptible to intergranular environmental assisted cracking: the C5A forging material exhibited a SCC crack-tip stress-intensity factor threshold of less than 6 MPadn. Fracture toughness tests revealed that the C5A forging material exhibited a fracture toughness that was 25% less than the C5B forging. The C5A forging exhibited rapid laboratory air fatigue crack growth rates having a threshold crack-tip stress-intensity factor range of less than 0.8 MPa sup m. Detailed fractographic examinations revealed that the ,fatigue crack intergranular growth crack path was similar to the cracking observed in the C5A tie box forging. Because both fatigue crack propagation and SCC exhibit similar intergranular crack path behavior, the damage mechanism resulting in multi-site cracking of tie box forgings cannot be determined unless local cyclic stresses can be quantified.

  3. Altered spatial arrangement of layer V pyramidal cells in the mouse brain following prenatal low-dose X-irradiation. A stereological study using a novel three-dimensional analysis method to estimate the nearest neighbor distance distributions of cells in thick sections.

    Science.gov (United States)

    Schmitz, Christoph; Grolms, Norman; Hof, Patrick R; Boehringer, Robert; Glaser, Jacob; Korr, Hubert

    2002-09-01

    Prenatal X-irradiation, even at doses <1 Gy, can induce spatial disarray of neurons in the brains of offspring, possibly due to disturbed neuronal migration. Here we analyze the effects of prenatal low-dose X-irradiation using a novel stereological method designed to investigate the three-dimensional (3D) spatial arrangement of neurons in thick sections. Pregnant mice were X-irradiated with 50 cGy on embryonic day 13 or were sham-irradiated. The right brain halves of their 180-day-old offspring were dissected into entire series of 150 microm thick frontal cryostat sections and stained with gallocyanin. Approximately 700 layer V pyramidal cells per animal were sampled in a systematic-random manner in the middle of the section's thickness. The x-y-z coordinates of these 'parent neurons' were recorded, as well as of all neighboring (up to 10) 'offspring neurons' close to each 'parent neuron'. From these data, the nearest neighbor distance (NND) distributions for layer V pyramidal cells were calculated. Using this novel 3D analysis method, we found that, in comparison to controls, prenatal X-irradiation had no effect on the total neuron number, but did cause a reduction in the mean volume of layer V by 26.5% and a more dispersed spatial arrangement of these neurons. Considering the recent literature, it seems reasonable to consider abnormal neuronal migration as the potential basic cause of this finding.

  4. The Ties That Bind: How Social Capital Is Forged and Forfeited in Teacher Communities

    Science.gov (United States)

    Bridwell-Mitchell, E. N.; Cooc, North

    2016-01-01

    The effects of social capital on school improvement make it important to understand how teachers forge, maintain, or forfeit collegial relationships. Two common explanations focused on formal organizational features and individual characteristics do not address how social capital accrues from informal dynamics of teachers' interactions in…

  5. 76 FR 8773 - Forged Stainless Steel Flanges From India and Taiwan

    Science.gov (United States)

    2011-02-15

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Forged Stainless Steel Flanges From India and Taiwan AGENCY: United States International Trade... steel flanges from India and Taiwan would be likely to lead to continuation or recurrence of...

  6. Fabrication Improvement of Cold Forging Hexagonal Nuts by Computational Analysis and Experiment Verification

    Directory of Open Access Journals (Sweden)

    Shao-Yi Hsia

    2015-01-01

    Full Text Available Cold forging has played a critical role in fasteners and has been applied to the automobile industry, construction industry, aerospace industry, and living products so that cold forging presents the opportunities for manufacturing more products. By using computer simulation, this study attempts to analyze the process of creating machine parts, such as hexagonal nuts. The DEFORM-3D forming software is applied to analyze the process at various stages in the computer simulation, and the compression test is also used for the flow stress equation in order to compare the differences between the experimental results and the equation that is built into the computer simulation software. At the same time, the metallography and hardness of experiments are utilized to understand the cold forging characteristics of hexagonal nuts. The research results would benefit machinery businesses to realize the forging load and forming conditions at various stages before the fastener formation. In addition to planning proper die design and production, the quality of the produced hexagonal nuts would be more stable to promote industrial competitiveness.

  7. Fatigue properties of high-strength materials used in cold-forging tools

    DEFF Research Database (Denmark)

    Brøndsted, P.; Skov-Hansen, P.

    1998-01-01

    In the present work classical analytical models are used to describe the static stress–strain curves, low-cycle fatigue properties and fatigue crack growth behaviour of high-strength materials for use in tools for metal-forming processes such as cold forging and extrusion. The paper describes...

  8. Numerical modeling of axi-symmetrical cold forging process by ``Pseudo Inverse Approach''

    Science.gov (United States)

    Halouani, A.; Li, Y. M.; Abbes, B.; Guo, Y. Q.

    2011-05-01

    The incremental approach is widely used for the forging process modeling, it gives good strain and stress estimation, but it is time consuming. A fast Inverse Approach (IA) has been developed for the axi-symmetric cold forging modeling [1-2]. This approach exploits maximum the knowledge of the final part's shape and the assumptions of proportional loading and simplified tool actions make the IA simulation very fast. The IA is proved very useful for the tool design and optimization because of its rapidity and good strain estimation. However, the assumptions mentioned above cannot provide good stress estimation because of neglecting the loading history. A new approach called "Pseudo Inverse Approach" (PIA) was proposed by Batoz, Guo et al.. [3] for the sheet forming modeling, which keeps the IA's advantages but gives good stress estimation by taking into consideration the loading history. Our aim is to adapt the PIA for the cold forging modeling in this paper. The main developments in PIA are resumed as follows: A few intermediate configurations are generated for the given tools' positions to consider the deformation history; the strain increment is calculated by the inverse method between the previous and actual configurations. An incremental algorithm of the plastic integration is used in PIA instead of the total constitutive law used in the IA. An example is used to show the effectiveness and limitations of the PIA for the cold forging process modeling.

  9. Tribo-thermal fatigue of the steel used for the forging die construction

    Science.gov (United States)

    Drumeanu, A. C.

    2017-02-01

    Frequently the durability of the forging dies is firstly determined by the non-isothermal fatigue wear, which causes the cracks appearance on their internal surfaces, much more before their abrasion wear to reach the limit value. In these conditions it is necessary to design the forging dies firstly by the point of view of the non-isothermal fatigue wear. For a correctly choosing and using of metallic material, it is necessary to determine their intrinsic characteristics regarding its cyclic non-isothermal stresses durability. The experimental determination of these characteristics implies a lot of experiments, which are done in specific conditions, different from those used for isothermal mechanical fatigue durability determination. The paper presents the experimental results concerning intrinsic characteristic determination of the forging dies steel. Based on these results there were determined specific equations which characterize this kind of stresses, and the diagrams that represent their graphic image. These data can be used both in designing and exploitation of the forging dies.

  10. Effect of key factors on cold orbital forging of a spur bevel gear

    Institute of Scientific and Technical Information of China (English)

    庄武豪; 董丽颖

    2016-01-01

    Cold orbital forging is an advanced spur bevel gear forming technology. Generally, the spur bevel gear in the cold orbital forging process is formed by two steps: the preforming step and the final step. Due to the great importance of the final step to gear forming and its complication with interactive factors, this work aims at examining the influence of key factors on the final step in cold orbital forging of a spur bevel gear. Using the finite element (FE) method and control variate method, the influence rules of four key factors, rotation velocity of the upper tool,n, feeding velocity of the lower tool,v, tilted angle of the upper tool,γ, friction factor between the tools and the billet,m, on the geometry and the deformation inhomogeneity of the cold orbital forged gear are thoroughly clarified. The research results show that the flash becomes more homogeneous with increasingv, increasingm, decreasing n or decreasingγ. And the deformation of the gear becomes more homogeneous with increasingv, decreasingn or decreasingγ. Finally, a corresponding experiment is conducted, which verifies the accuracy of FE simulation conclusions.

  11. Jernberg Industries, Inc: Forging Facility Uses Plant-Wide Assessment to Aid Conversion to Lean Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-10-01

    Jernberg Industries conducted a plant-wide assessment while converting to lean manufacturing at a forging plant. Seven projects were identified that could yield annual savings of $791,000, 64,000 MMBtu in fuel and 6 million kWh.

  12. Influence of the hydrostatic stress component on critical surface expansion in forging compound products

    DEFF Research Database (Denmark)

    Vorm, T; Bay, Niels; Wanheim, Tarras

    1974-01-01

    of a superimposed hydrostatic pressure on the critical surface expansion during a forging process. The critical surface expansion appears to decrease with increasing hydrostatic pressure. This may be due to the fact that the close contact between the materials necessary to obtain bonding is created by a micro...

  13. Hot Cutting of Real-Time Cast-Forged GS Ductile Iron for Automotive Rods

    Science.gov (United States)

    Fouilland, Laurence; Mansori, Mohamed El

    2011-01-01

    In the global economy context, automotive industry suppliers have to keep a constant advance on products design and manufacturing process. Concerning automotive rods, the substitution of forged steel by spherical graphite iron (SG iron) with high mechanical properties constitutes a valid economic alternative. Such rods are produced using a complex coupled process: casting and forging followed by an austempered heat treatment. The forging operation is capable to shape the cast rod which introduces hot deformation to increase mechanical properties of net-shape SG iron rod. However, the intermediate re-heating between casting and forging must be avoided to keep competitive manufacturing costs. A major concern of this new process development is the cracks produced in rod's surface which are consecutive to hot spruing involved after casting operations. This issue is addressed in this paper which discusses the physical mechanisms involved in the hot ductile damage of SG iron. Hot cutting tests were performed to simulate the spruing operation which shows the close interactions between microstructure, machining parameters and resulting damages. The damage mechanisms in terms of crack initiation and its growth have been studied with respect to the constituent phases (austenite+graphite nodules), the cut surface morphology and the hot cutting performance.

  14. Social Work and Engineering Collaboration: Forging Innovative Global Community Development Education

    Science.gov (United States)

    Gilbert, Dorie J.

    2014-01-01

    Interdisciplinary programs in schools of social work are growing in scope and number. This article reports on collaboration between a school of social work and a school of engineering, which is forging a new area of interdisciplinary education. The program engages social work students working alongside engineering students in a team approach to…

  15. HaploForge: A Comprehensive Pedigree Drawing and Haplotype Visualisation Web Application.

    Science.gov (United States)

    Tekman, Mehmet; Medlar, Alan; Mozere, Monika; Kleta, Robert; Stanescu, Horia

    2017-08-14

    Haplotype reconstruction is an important tool for understanding the aetiology of human disease. Haplotyping infers the most likely phase of observed genotypes conditional on constraints imposed by the genotypes of other pedigree members. The results of haplotype reconstruction, when visualised appropriately, show which alleles are identical by descent despite the presence of untyped individuals. When used in concert with linkage analysis, haplotyping can help delineate a locus of interest and provide a succinct explanation for the transmission of the trait locus. Unfortunately, the design choices made by existing haplotype visualisation programs do not scale to large numbers of markers. Indeed, following haplotypes from generation to generation requires excessive scrolling back and forth. In addition, the most widely-used program for haplotype visualisation produces inconsistent recombination artefacts for the X chromosome. To resolve these issues, we developed HaploForge, a novel web application for haplotype visualisation and pedigree drawing. HaploForge takes advantage of HTML5 to be fast, portable and avoid the need for local installation. It can accurately visualise autosomal and X-linked haplotypes from both outbred and consanguineous pedigrees. Haplotypes are coloured based on identity by descent using a novel A* search algorithm and we provide a flexible viewing mode to aid visual inspection. HaploForge can currently process haplotype reconstruction output from Allegro, GeneHunter, Merlin and Simwalk. HaploForge is licensed under GPLv3 and is hosted and maintained via GitHub. Supplementary data is available from Bioinformatics online.

  16. eFORGE : A Tool for Identifying Cell Type-Specific Signal in Epigenomic Data

    NARCIS (Netherlands)

    Breeze, Charles E.; Paul, Dirk S.; van Dongen, Jenny; Butcher, Lee M.; Ambrose, John C.; Barrett, James E.; Lowe, Robert; Rakyan, Vardhman K.; Iotchkova, Valentina; Frontini, Mattia; Downes, Kate; Ouwehand, Willem H.; Laperle, Jonathan; Jacques, Pierre-ETienne; Bourque, Guillaume; Bergmann, Anke K.; Siebert, Reiner; Vellenga, Edo; Saeed, Sadia; Matarese, Filomena; Martens, Joost H. A.; Stunnenberg, Hendrik G.; Teschendorff, Andrew E.; Herrero, Javier; Birney, Ewan; Dunham, Ian; Beck, Stephan

    2016-01-01

    Epigenome-wide association studies (EWAS) provide an alternative approach for studying human disease through consideration of non-genetic variants such as altered DNA methylation. To advance the complex interpretation of EWAS, we developed eFORGE (http://eforge.cs.ucl.ac.uk/), a new stand-alone and

  17. Evaluation of Subsequent Heat Treatment Routes for Near-β Forged TA15 Ti-Alloy

    Directory of Open Access Journals (Sweden)

    Zhichao Sun

    2016-10-01

    Full Text Available TA15 Ti-alloy is widely used to form key load-bearing components in the aerospace field, where excellent service performance is needed. Near-β forging technology provides an attractive way to form these complicated Ti-alloy components but subsequent heat treatment has a great impact on the final microstructure and mechanical properties. Therefore evaluation and determination of the heat treatment route is of particular significance. In this paper, for the near-β forged TA15 alloy, the formation and evolution of microstructures under different subsequent heat treatment routes (annealing, solution and aging, toughening and strengthening were studied and the cooling mode after forging was also considered. Then, the type and characteristics of the obtained microstructures were discussed through quantitative metallographic analysis. The corresponding mechanical properties (tensile, impact toughness, and fracture toughness and effects of microstructural characteristics were investigated. Finally, for a required microstructure and performance a reasonable heat treatment route was recommended. The work is of importance for the application and development of near-β forging technology.

  18. Effects of Different Forging Processes on Microstructure Evolution for 316LN Austenitic Stainless Steel

    Science.gov (United States)

    Sui, Dashan; Zhu, Lingling; Wang, Tao; Zhang, Peipei; Cui, Zhenshan

    2017-07-01

    Forging experiments were designed and carried out on a 3150 kN hydraulic press to investigate the effects of different processes on the microstructure evolution for 316LN steel. The forging processes included single-pass (upsetting) and multipass (stretching) deformations, and the experimental results indicated that the average grain size varied with forging processes. Moreover, the size had distinct differences at different positions in the workpiece. Meanwhile, numerical simulations were implemented to study the influence of temperature, strain, and strain rate on microstructure evolution. The results of experiments and simulations comprehensively demonstrated that dynamic, static, and meta-dynamic recrystallization could coexist in the hot forging process and that the recrystallization process could easily occur under the conditions of higher temperature, larger strain, and higher strain rate. Moreover, the temperature had more significant influence on both recrystallization and grain growth. A higher temperature could not only promote the recrystallization but also speed up the grain growth. Therefore, a lower temperature is beneficial to obtain refinement grains on the premise that the recrystallization can occur completely.

  19. Physical modeling and numerical simulation of V-die forging ingot with central void

    DEFF Research Database (Denmark)

    Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

    2014-01-01

    Numerical simulation and physical modeling performed on small-scale ingots made from pure lead, having a hole drilled through their centerline to mimic porosity, are utilized to characterize the deformation mechanics of a single open die forging compression stage and to identify the influence...

  20. Preform design optimization for forging process based on the topological approach

    Science.gov (United States)

    Shao, Yong; Lu, Bin; Ou, Hengan; Cui, Zhenshan

    2013-05-01

    Preform design plays an important role in forging design especially for parts with complex shapes. In this paper, an attempt was made to develop a topological approach in the preform design of bulk metal forming processes based on the Bi-direction evolutionary structural optimization (BESO) strategy. In this approach, a new element addition and removal criteria based on the equivalent strain have been proposed for evaluating and optimizing the material flow in the forging process. To obtain a smooth preform boundary, a closed B-spline curve based on the least square approximation algorithm is employed to approximate the uneven surface of updated preform. An inhouse developed C♯ program has been employed to integrate the FE simluation, shape optimsation and surface approximation process. A 2D blade forging perform design problem are evaluate using the developed method. The results suggest that the optimized preform has shown better performance in improving the material flow and deformation uniformity during the forging. The results also demonstrate the robustness and efficiency of the developed preform design optimization method.

  1. Influence of forming velocity on the uniformity of microstructure of semisolid die forging 7075 alloy

    Directory of Open Access Journals (Sweden)

    Jianbo TAN

    2016-12-01

    Full Text Available Liquid phase segregation frequently occurs in the process of semi solid die forging, which makes the parts appear "weak point" or "weak region", and usually, the "weak point" or "weak area" is the reason of crack and service condition failure. In order to analyze the influence factors of the liquid phase segregation of the semi solid die forging, DEFORM-3D is used for the numerical simulation of semi-solid die forging forming process of 7075 aluminum alloy, to study the influence rule of forming velocity on the forming process of cup part. Based on the simulation results, the rheological die forging forming of 7075 aluminum alloythe part is conducted to research the influence of forming velocity on the uniformity of microstructure by means of press machine and cup mould. The simulation and experimental results show that as the filling velocity is faster, the forming process is more unstable; under the condition of head temperature of 400 ℃, the forming pressure of 50 MPa, and the alloy temperature 628 ℃, as the forming velocity increases, the liquid phase segregation degree of cup part increases, and the microstructure is far from uniformity. The segregation degree is up to 18.2% as the forming velocity is 5 mm/s.

  2. Education and "Thick" Epistemology

    Science.gov (United States)

    Kotzee, Ben

    2011-01-01

    In this essay Ben Kotzee addresses the implications of Bernard Williams's distinction between "thick" and "thin" concepts in ethics for epistemology and for education. Kotzee holds that, as in the case of ethics, one may distinguish between "thick" and "thin" concepts of epistemology and, further, that this distinction points to the importance of…

  3. Thick film hydrogen sensor

    Science.gov (United States)

    Hoffheins, Barbara S.; Lauf, Robert J.

    1995-01-01

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

  4. Forming of Hollow Shaft Forging From Titanium Alloy Ti6Al4V by Means of Rotary Compression

    Directory of Open Access Journals (Sweden)

    Tomczak J.

    2015-04-01

    Full Text Available This paper presents chosen results of theoretical-experimental works concerning forming of hollow shafts forgings from titanium alloys, which are applied in aviation industry. At the first stage of conducted analysis, the forging forming process was modeled by means of finite element method. Calculations were made using software Simufact Forming. On the basis of performed simulations optimal parameters of rotary compression process were determined. Next, experimental tests of forging forming in laboratory conditions were made. For the research needs, a forging aggregate, designed by the Authors, was used. Conducted research works confirmed the possibility of metal forming (by means of rotary compression of hollow shafts from hard workable titanium alloys. Numerous advantages of rotary compression process, make it attractive both for low series production (aircraft industry and for mass production (automotive industry.

  5. Effects of Cryogenic Forging and Anodization on the Mechanical Properties of AA 7075-T73 Aluminum Alloys

    Science.gov (United States)

    Shih, Teng-Shih; Liao, Tien-Wei; Hsu, Wen-Nong

    2016-03-01

    In this study, high-strength AA7075 alloy samples were cryogenically forged after annealing and then subjected to solution and aging treatments. The cryogenically forged 7075-T73 alloy samples displayed equiaxed fine grains associated with abundant fine precipitates in their matrix. Compared with conventional 7075-T73 alloy samples, the cryogenically forged samples exhibited an 8-12% reduction in tensile strength and an increased fatigue strength and higher corrosion resistance. The fatigue strength measured at 107 cycles was 225 MPa in the bare samples; the strength was increased to 250 MPa in the cryogenically forged samples. The effect of anodization on the corrosion resistance of the bare samples was improved from (E corr) -0.80 to -0.61 V.

  6. Fabrication and densification enhancement of SiC-particulate-reinforced copper matrix composites prepared via the sinter-forging process

    Institute of Scientific and Technical Information of China (English)

    Mohammadmehdi Shabani; Mohammad Hossein Paydar; Mohammad Mohsen Moshksar

    2014-01-01

    The fabrication of copper (Cu) and copper matrix silicon carbide (Cu/SiCp) particulate composites via the sinter-forging process was investigated. Sintering and sinter-forging processes were performed under an inert Ar atmosphere. The influence of sinter-forging time, tempera-ture, and compressive stress on the relative density and hardness of the prepared samples was systematically investigated and subsequently com-pared with that of the samples prepared by the conventional sintering process. The relative density and hardness of the composites were enhanced when they were prepared by the sinter-forging process. The relative density values of all Cu/SiCp composite samples were observed to decrease with the increase in SiC content.

  7. A friction model for cold forging of aluminum, steel and stainless steel provided with conversion coating and solid film lubricant

    DEFF Research Database (Denmark)

    Bay, Niels; Eriksen, Morten; Tan, Xincai

    2011-01-01

    Adopting a simulative tribology test system for cold forging the friction stress for aluminum, steel and stainless steel provided with typical lubricants for cold forging has been determined for varying normal pressure, surface expansion, sliding length and tool/work piece interface temperature...... of normal pressure and tool/work piece interface temperature. The model is verified by process testing measuring friction at varying reduction in cold forward rod extrusion....

  8. Construction of a visual determination method on the thickness and surface of APA Microcapsules by optica microscopy with frozen section and the ice emission scanning electron microscopy%采用冰冻切片和冷场发射电镜构建APA微囊的膜厚度及膜表面测定的方法研究

    Institute of Scientific and Technical Information of China (English)

    傅红兴; 李慧; 朱雁林; 赵应征; 吴岚岚; 江玲

    2013-01-01

    目的:建立一种APA微囊的膜厚度以及表面结构的检测方法,并测定微囊在湿状态的膜厚度和干燥后的膜表面结构.方法:采用亚甲蓝染色、冰冻切片结合光学显微镜观察微囊的膜厚度,并将囊膜在37℃孵育30 d后再次观察厚度的变化;对微囊进行冷冻干燥和冷场发射观察囊膜表面和断面结构.结果:APA-Ca和APA-Ba微囊的囊膜厚度并不均匀,孵育1个月后囊膜厚度变化差异无统计学意义(P>0.05);冷场发射扫描电镜下显示,两种微囊表面均光滑、致密;冻干后APA-Ca囊膜厚度达450 ~690 nm,而APA-Ba的囊膜厚度约为350 nm.结论:建立了一种简单、可靠的微囊膜厚度和表面检测方法,为进一步研究APA微囊的质量奠定了基础.%Objective: To explore a visual methold of the membrane thickness of APA microcapsules and their surface structures, and determinate the film thickness and surface characteristics. Methods: We use methyl-ene blue to dye the film of microcapsules, then within frozen section and optical microscope the the thickness of microcapsule were observed; and the thickness of microcapsules hatched in 37 ℃ for a month were also assayed. The surface of membrane were studied by ice emission scanning electron microscopy after lyophilization. Results: The member thickness of each APA microencapsules is not uniform. After incubated for 30 d in 37 ℃, there is no obviously difference in the thichness than befor (P>0.05). Surfaces of two microencapsules are smooth and compact under the scanning electron microscopy. The thickness of APA-Ca microcapsules are 450-690 nm, which of APA-Ba are about 350 nm. Conclusion: The essay provided a simple method on how to determine the membrane thickness and surface, which would be an important reference to expound the APA microcapsules.

  9. Effects of Process Parameters on Deformation and Temperature Uniformity of Forged Ti-6Al-4V Turbine Blade

    Science.gov (United States)

    Luo, Shiyuan; Zhu, Dahu; Hua, Lin; Qian, Dongsheng; Yan, Sijie; Yu, Fengping

    2016-11-01

    This work is motivated by the frequent occurrence of macro- and microdefects within forged Ti-6Al-4V turbine blades due to the severely nonuniform strain and temperature distributions. To overcome the problem of nonuniformity during the blade forging operation, firstly, a 2D coupled thermo-mechanical finite element approach using the strain-compensated Arrhenius-type constitutive model is employed to simulate the real movements and processing conditions, and its reliability is verified experimentally. Secondly, two evaluation indexes, standard deviation of equivalent plastic strain and standard deviation of temperature, are proposed to evaluate the uniformity characteristics within the forged blade, and the effects of four process parameters including the forging velocity, friction factor, initial workpiece temperature and dwell time on the uniformity of strain and temperature distributions are carefully studied. Finally, the numerically optimized combination of process parameters is validated by the application in a practical process. The parametric study reveals that a reasonable combination of process parameters considering the flow resistance, flow localization and the effects of deformation and friction heating is crucial for the titanium alloy blade forging with uniformity. This work can provide a significant guidance for the design and optimization of blade forging processes.

  10. Numerical simulation and experimental study for the die forging process of a high-speed railway brake disc hub

    Science.gov (United States)

    Sun, Mingyue; Xu, Bin; Zhang, Long; LI, Dianzhong

    2013-05-01

    With the aim of manufacturing a near-net shape forging product of a brake disk hub for the high-speed railway, the die forging process was designed and optimized in this study. Firstly, based on the measured stress-strain curves at different strain rates and the thermal-physical parameters of 40Cr A steel, a finite element model for the forging process of a high-speed railway brake disc hub was established. Then, the temperature, stress and strain fields were studied and analyzed at the pre-forging and the finial-forging stages. Besides, in order to trace the stress and strain evolution, five points at different positions were chosen on the billet, and the comparison of the state conditions was made among these points. The results have demonstrated that the product can be well formed by an elaborately designed three-stage forging process, which may reduce the metal machine allowance and the producing cost effectively. Finally, an industrial trial was made and a machined product with sound quality was obtained.

  11. Ocean Sediment Thickness Contours

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ocean sediment thickness contours in 200 meter intervals for water depths ranging from 0 - 18,000 meters. These contours were derived from a global sediment...

  12. Origami of thick panels

    Science.gov (United States)

    Chen, Yan; Peng, Rui; You, Zhong

    2015-07-01

    Origami patterns, including the rigid origami patterns in which flat inflexible sheets are joined by creases, are primarily created for zero-thickness sheets. In order to apply them to fold structures such as roofs, solar panels, and space mirrors, for which thickness cannot be disregarded, various methods have been suggested. However, they generally involve adding materials to or offsetting panels away from the idealized sheet without altering the kinematic model used to simulate folding. We develop a comprehensive kinematic synthesis for rigid origami of thick panels that differs from the existing kinematic model but is capable of reproducing motions identical to that of zero-thickness origami. The approach, proven to be effective for typical origami, can be readily applied to fold real engineering structures.

  13. Backward can extrusion with conical,rotating punch as a cold forging tribology test

    DEFF Research Database (Denmark)

    Ceron, Ermanno; Bay, Niels; Tetsuo, A.

    2011-01-01

    A new, simulative test of friction and lubrication in cold forging is developed by the authors. The test is based on a backward can extrusion process in which the workpiece rotates. An analytical model is presented determining the friction stress from the measured torque during testing combined...... with an analysis of the sliding velocity distribution along the punch nose. The latter is determined by FE analysis of the test. Results show friction stress for unalloyed low C-steel provided with different types of lubricants, e.g. phosphate coating plus soap, phosphate coating plus MoS2 and single bathe...... lubrication with PULS. The new test is so severe, that it is possible to break down the best lubrication systems for cold forging, such as phosphate coating plus soap and MoS2....

  14. MODELING OF MICROSTRUCTURAL EVOLUTION IN MICROALLOYED STEEL DURING HOT FORGING PROCESS

    Institute of Scientific and Technical Information of China (English)

    J. Wang; J. Chen; Z. Zhao; X.Y. Ruan

    2006-01-01

    The microstructural evolution of microalloyed steel during hot forging process was investigated using physical simulation experiments. The dynamic recrystallized fraction was described by modifying Avrami's equation, the parameters of which were determined by single hit compression tests. Double hit compression tests were performed to model the equation describing the static recrystallized fraction, and the obtained predicted values were in good agreement with the measured values. Austenitic grain growth was modeled as: Dinc5=D05 +1.6×1032t·exp(-716870/RT) using isothermal tests. Furthermore, an equation describing the dynamic recrystallized grain size was given as Ddyn=3771·Z-0.2.The models of microstructural evolution could be applied to the numerical simulation of hot forging.

  15. Application of multi-grid method on the simulation of incremental forging processes

    Science.gov (United States)

    Ramadan, Mohamad; Khaled, Mahmoud; Fourment, Lionel

    2016-10-01

    Numerical simulation becomes essential in manufacturing large part by incremental forging processes. It is a splendid tool allowing to show physical phenomena however behind the scenes, an expensive bill should be paid, that is the computational time. That is why many techniques are developed to decrease the computational time of numerical simulation. Multi-Grid method is a numerical procedure that permits to reduce computational time of numerical calculation by performing the resolution of the system of equations on several mesh of decreasing size which allows to smooth faster the low frequency of the solution as well as its high frequency. In this paper a Multi-Grid method is applied to cogging process in the software Forge 3. The study is carried out using increasing number of degrees of freedom. The results shows that calculation time is divide by two for a mesh of 39,000 nodes. The method is promising especially if coupled with Multi-Mesh method.

  16. Volume calculation of the spur gear billet for cold precision forging with average circle method

    Institute of Scientific and Technical Information of China (English)

    Wangjun Cheng; Chengzhong Chi; Yongzhen Wang; Peng Lin; Wei Liang; Chen Li

    2014-01-01

    Forging spur gears are widely used in the driving system of mining machinery and equipment due to their higher strength and dimensional accuracy. For the purpose of precisely calculating the volume of cylindrical spur gear billet in cold precision forging, a new theoretical method named average circle method was put forward. With this method, a series of gear billet volumes were calculated. Comparing with the accurate three-dimensional modeling method, the accuracy of average circle method by theoretical calculation was estimated and the maximum relative error of average circle method was less than 1.5%, which was in good agreement with the experimental results. Relative errors of the calculated and the experimental for obtaining the gear billet volumes with reference circle method are larger than those of the average circle method. It shows that average circle method possesses a higher calculation accuracy than reference circle method (traditional method), which should be worth popularizing widely in calculation of spur gear billet volume.

  17. Fatigue life on a full scale test rig: Forged versus cast wind turbine rotor shafts

    Science.gov (United States)

    Herrmann, J.; Rauert, T.; Dalhoff, P.; Sander, M.

    2016-09-01

    To reduce uncertainties associated with the fatigue life of the highly safety relevant rotor shaft and also to review today's design practice, the fatigue behaviour will be tested on a full scale test rig. Until now tests on full scale wind turbine parts are not common. Therefore, a general lack of experience on how to perform accelerated life time tests for those components exists. To clarify how to transfer real conditions to the test environment, the arrangements and deviations for the upcoming experimental test are discussed in detail. In order to complete investigations of weight saving potentials, next to getting a better comprehension of the fatigue behaviour by executing a full scale test, a further outcome are suggestions for the usage of cast and forged materials regarding the fatigue and the remaining life of the rotor shaft. It is shown, that it is worthwhile to think about a material exchange for the forged rotor shaft.

  18. Study of Dynamic Characteristics for Hydraulic System on 300MN Die-forging Press

    Science.gov (United States)

    Chen, Guoqiang; Tan, Jianping

    2017-06-01

    The faults such as seal breakdown and pressure sensor damage occur in 300MN Die-forging press frequently. First, the fault phenomenon and harm of the hydraulic system was compiled statistics, the theoretical analysis of the hydraulic impact of hydraulic system are carried out based on the momentum theorem; Then, the co-simulation model of hydraulic system was established by AMESim and Simulink software and the correctness was verified. Finally, the dynamic characteristics of hydraulic system for the key working condition “forging stroke changing to mold collision” was analyzed, the influences rules of system parameters such as the leak gap of valve, diameter of water way pipeline, emulsion temperature and air contain act on hydraulic system are obtained. This conclusions have a theoretical guiding significance to the improvement and maintains of high pressure and large flow hydraulic system.

  19. Effect of multiaxial forging on microstructure and mechanical properties of Mg-o.8Ca alloy

    Science.gov (United States)

    Yurchenko, N. Yu; Stepanov, N. D.; Salishchev, G. A.; Rokhlin, L. L.; Dobatkin, S. V.

    2014-08-01

    It was shown that multiaxial forging with continuous decrease of temperature from 450°C to 250°C turns coarse structure of the Mg-0.8Ca alloy in homogenized state with grain size of several hundreeds gm into fine structure with average grain size of about 2.1 gm. Refinement of structure is accompanied by drastic increase of mechanical properties: tensile yield strength increases from 50 MPa to 193 MPa, ultimate tensile strength increases from 78 to 308 MPa and elongation to fracture increases from 3.0% to 7.2%. The microstructural evolution during multiaxial forging is studied using optical microscopy, scanning electron microscopy and EBSD analysis. The mechanisms responsible for refinement of microstructure are discussed

  20. Qualification of laser based additive production for manufacturing of forging Tools

    Directory of Open Access Journals (Sweden)

    Junker Daniel

    2015-01-01

    Full Text Available Mass customization leads to very short product life cycles, so the costs of a tool have to be amortized with a low number of workpieces. Especially for highly loaded tools, like those for forging, that leads to expensive products. Therefore more economical production processes for tool manufacturing have to be investigated. As laser additive manufacturing is already used for the production of moulds for injection moulding, this technology maybe could also improve the forging tool production. Within this paper laser metal deposition, which is industrially used for tool repair, will be investigated for the use in tool manufacturing. Therefore a mechanical characterization of parts built with different laser process parameters out of the hot work tool steel 1.2709 is made by upsetting tests and hardness measurements. So the influence of the additive manufacturing process on the hardness distribution is analysed.

  1. Effect of interfacial friction during forging of solid powder discs of large slenderness ratio

    Indian Academy of Sciences (India)

    R K Ranjan; S Kumar

    2004-10-01

    The paper reports an investigation into the effect of interfacial friction law during the forging of a powder circular disc with large slenderness ratio (L/D) between two flat dies. The deformation pattern during the operation is influenced by many factors, which interact with each other in a complex manner. The relative velocity between the work piece material and the die surface, together with high interfacial pressure and/or deformation modes, creates the conditions essential for adhesion in addition to sliding. The decisive factors are the interfacial conditions, initial relative density of the preform and geometry of the preform. An attempt has been made to determine the most realistic interfacial friction law and die pressures developed during such forging using an upper bound approach. The results so obtained are presented graphically and discussed critically to illustrate the interaction of various interfacial friction laws involved.

  2. Evolution of the Ultrasonic Inspection of Heavy Rotor Forgings Over the Last Decades

    Science.gov (United States)

    Zimmer, A.; Vrana, J.; Meiser, J.; Maximini, W.; Blaes, N.

    2010-02-01

    All types of heavy forgings that are used in energy machine industry, rotor shafts as well as discs, retaining rings or tie bolts are subject to extensive nondestructive inspections before they are delivered to the customer. Due to the availability of the parts in simple shapes, these forgings are very well suited for full volmetric inspections using ultrasound. In the beginning, these inspections were carried out manually, using straight beam probes and analogue equipment. Higher requirements in reliability, efficiency, safety and power output in the machines have lead to higher requirements for the ultrasonic inspection in the form of more scanning directions, higher sensitivity demands and improved documentation means. This and the increasing use of high alloy materials for ever growing parts, increase the need for more and more sophisticated methods for testing the forgings. Angle scans and sizing technologies like DGS have been implemented, and for more than 15 years now, mechanized and automated inspections have gained importance since they allow better documentation as well as easier evaluation of the recorded data using different views (B- C- or D-Scans), projections or tomography views. The latest major development has been the availability of phased array probes to increase the flexibility of the inspection systems. Many results of the ongoing research in ultrasonic's have not been implemented yet. Today's availability of fast computers, large and fast data storages allows saving RF inspection data and applying sophisticated signal processing methods. For example linear diffraction tomography methods like SAFT offer tools for 3D reconstruction of inspection data, simplifying sizing and locating of defects as well as for improving signal to noise ratios. While such methods are already applied in medical ultrasonic's, they are still to be implemented in the steel industry. This paper describes the development of the ultrasonic inspection of heavy forgings

  3. Determination and Analysis of Hardenability for Hot-Forging Die Steels with Deep-Hardening

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    ERH end-quenching method was us ed to determine the hardenability of four kinds hot-forging die steels with dee p-hardening and hence the order of their hardenability was given. The tempering hardness of the steels was measured and the tempering resistance was studied. It was approved that ERH method is effective for the determination of hardenability of deep-hardening steel and the beginning of hardness drop in the ERH specimen is caused by bainite occurring.

  4. DYNAMIC SIMULATION OF MICROSTRUCTURE EVOLUTION DURING HOT FORGING FOR ENGINE STIGMATA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Incorporated with constitutive relationship established by artificial neural networks (ANN), a coupled theroviscoplastic finite element procedure is developed for predicting the microstructure evolution in the hot forging process, considering the factors such as dynamic recrystallization, static recrystallization and grain growth etc. This software system is applied to predict the distributions of the grain size over the crosssection of stigmata, which is found to be in good agreement with the experimental results. The software can provide a fundament for optimizing technological parameters.

  5. Die Motions of New Forging Process Using IntermediateDie Assembly

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The die motions of a new forging process for automation with an intermediate die assembly called hamburger were analyzed through high-speed video pictures. The results showed that the upper die that is assembled in the hamburger and retained over the lower die collides few times with the ram and workpiece, but sound products can be obtained with less sticking in spite of the lowered impacts of hit.

  6. Wear Improvement of Tools in the Cold Forging Process for Long Hex Flange Nuts.

    Science.gov (United States)

    Hsia, Shao-Yi; Shih, Po-Yueh

    2015-09-25

    Cold forging has played a critical role in fasteners and has been widely used in automotive production, manufacturing, aviation and 3C (Computer, Communication, and Consumer electronics). Despite its extensive use in fastener forming and die design, operator experience and trial and error make it subjective and unreliable owing to the difficulty of controlling the development schedule. This study used finite element analysis to establish and simulate wear in automotive repair fastener manufacturing dies based on actual process conditions. The places on a die that wore most quickly were forecast, with the stress levels obtained being substituted into the Archard equation to calculate die wear. A 19.87% improvement in wear optimization occurred by applying the Taguchi quality method to the new design. Additionally, a comparison of actual manufacturing data to simulations revealed a nut forging size error within 2%, thereby demonstrating the accuracy of this theoretical analysis. Finally, SEM micrographs of the worn surfaces on the upper punch indicate that the primary wear mechanism on the cold forging die for long hex flange nuts was adhesive wear. The results can simplify the development schedule, reduce the number of trials and further enhance production quality and die life.

  7. Non-destructive Testing of Forged Metallic Materials by Active Infrared Thermography

    Science.gov (United States)

    Maillard, S.; Cadith, J.; Bouteille, P.; Legros, G.; Bodnar, J. L.; Detalle, V.

    2012-11-01

    Nowadays, infrared thermography is considered as the reference method in many applications such as safety, the inspection of electric installations, or the inspection of buildings' heat insulation. In recent years, the evolution of both material and data-processing tools also allows the development of thermography as a real non-destructive testing method. Thus, by subjecting the element to be inspected to an external excitation and by analyzing the propagation of heat in the examined zone, it is possible to highlight surface or subsurface defects such as cracks, delaminations, or corrosion. One speaks then about active infrared thermography. In this study, some results obtained during the collective studies carried out by CETIM and the University of Reims for the forging industry are presented. Various experimental possibilities offered by active thermography are presented and the interest in this method in comparison with the traditional non-destructive testing methods (penetrant testing and magnetic particle inspection) is discussed. For example, comparative results on a forged cracked hub, a steering joint, and a threaded rod are presented. They highlight the interest of infrared thermography stimulated by induction for forged parts.

  8. Wear Improvement of Tools in the Cold Forging Process for Long Hex Flange Nuts

    Directory of Open Access Journals (Sweden)

    Shao-Yi Hsia

    2015-09-01

    Full Text Available Cold forging has played a critical role in fasteners and has been widely used in automotive production, manufacturing, aviation and 3C (Computer, Communication, and Consumer electronics. Despite its extensive use in fastener forming and die design, operator experience and trial and error make it subjective and unreliable owing to the difficulty of controlling the development schedule. This study used finite element analysis to establish and simulate wear in automotive repair fastener manufacturing dies based on actual process conditions. The places on a die that wore most quickly were forecast, with the stress levels obtained being substituted into the Archard equation to calculate die wear. A 19.87% improvement in wear optimization occurred by applying the Taguchi quality method to the new design. Additionally, a comparison of actual manufacturing data to simulations revealed a nut forging size error within 2%, thereby demonstrating the accuracy of this theoretical analysis. Finally, SEM micrographs of the worn surfaces on the upper punch indicate that the primary wear mechanism on the cold forging die for long hex flange nuts was adhesive wear. The results can simplify the development schedule, reduce the number of trials and further enhance production quality and die life.

  9. FEA Based Tool Life Quantity Estimation of Hot Forging Dies Under Cyclic Thermo-Mechanical Loads

    Science.gov (United States)

    Behrens, B.-A.; Bouguecha, A.; Schäfer, F.; Hadifi, T.

    2011-01-01

    Hot forging dies are exposed during service to a combination of cyclic thermo-mechanical, tribological and chemical loads. Besides abrasive and adhesive wear on the die surface, fatigue crack initiation with subsequent fracture is one of the most frequent causes of failure. In order to extend the tool life, the finite element analysis (FEA) may serve as a means for process design and process optimisation. So far the FEA based estimation of the production cycles until initial cracking is limited as tool material behaviour due to repeated loading is not captured with the required accuracy. Material models which are able to account for cyclic effects are not verified for the fatigue life predictions of forging dies. Furthermore fatigue properties from strain controlled fatigue tests of relevant hot work steels are to date not available to allow for a close-to-reality fatigue life prediction. Two industrial forging processes, where clear fatigue crack initiation has been observed are considered for a fatigue analysis. For this purpose the relevant tool components are modelled with elasto-plastic material behaviour. The predicted sites, where crack initiation occurs, agree with the ones observed on the real die component.

  10. Multipass forging of Inconel 718 in the delta-Supersolvus domain: assessing and modeling microstructure evolution

    Directory of Open Access Journals (Sweden)

    Zouari Meriem

    2014-01-01

    Full Text Available This work is focused on the evolution of the microstructure of Inconel 718 during multi-pass forging processes. During the forming process, the material is subjected to several physical phenomena such as work-hardening, recovery, recrystallization and grain growth. In this work, transformation kinetics are modeled in the δ-Supersolvus domain (T>Tsolvus where the alloy is single-phase, all the alloying elements being dissolved into the FCC matrix. Torsion tests were used to simulate the forging process and recrystallization kinetics was modeled using a discontinuous dynamic recrystallization (DDRX two-site mean field model. The microstructure evolution under hot forging conditions is predicted in both dynamic and post-dynamic regimes based on the initial distribution of grain size and the evolution of dislocation density distribution during each step of the process. The model predicts recrystallization kinetics, recrystallized grain size distribution and stress–strain curve for different thermo-mechanical conditions and makes the connection between dynamic and post-dynamic regimes.

  11. Forming limit prediction of powder forging process by the energy-based elastoplastic damage model

    Science.gov (United States)

    Yeh, Hung-Yang; Cheng, Jung-Ho; Huang, Cheng-Chao

    2004-06-01

    An energy-based elastoplastic damage model is developed and then applied to predict the deformation and fracture initiation in powder forging processes. The fracture mechanism is investigated by the newly proposed damage model, which is based on the plastic energy dissipation. The developed formulations are implemented into finite element program ABAQUS in order to simulate the complex loading conditions. The forming limits of sintered porous metals under various operational conditions are explored by comparing the relevant experiments with the finite element analyses. The sintered iron-powder preforms of various initial relative densities (RDs) and aspect ratios are compressed until crack initiates. The deformation level of the bulged billets at fracture stroke obtained from compressive fracture tests is utilized to validate the finite element model and then the forming limit diagrams are constructed with the validated model. This model is further verified by the gear blank forging. The fracture site and corresponding deformation level are predicted by the finite element simulations. Meanwhile, the gear forging experiment is performed on the sintered preforms. The predicted results agree well with the experimental observations.

  12. Effect of Alloying Elements on Thermal Wear of Cast Hot-Forging Die Steels

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-qi; CHEN Kang-min; CUI Xiang-hong; JIANG Qi-chuan; HONG Bian

    2006-01-01

    The effect of main alloying elements on thermal wear of cast hot-forging die steels was studied. The wear mechanism was discussed. The results show that alloying elements have significant influences on the thermal wear of cast hot-forging die steels. The wear rates decrease with an increase in chromium content from 3% to 4% and molybdenum content from 2% to 3%, respectively. With further increase of chromium and molybdenum contents, chromium slightly reduces the wear resistance and molybdenum severely deteriorates the wear resistance with high wear rate. Lower vanadium/carbon ratio (1.5-2.5) leads to a lower wear resistance with higher wear rate. With an increase in vanadium/carbon ratio, the wear resistance of the cast steel substantially increases. When vanadium/carbon ratio is 3, the wear rate reaches the lowest value. The predominant mechanism of thermal wear of cast hot-forging die steels are oxidation wear and fatigue delamination. The Fe2O3 and Fe3O4 or lumps of brittle wear debris are formed on the wear surface.

  13. The coarsening effect of SA508-3 steel used as heavy forgings material

    Directory of Open Access Journals (Sweden)

    Dingqian Dong

    2015-01-01

    Full Text Available SA508Gr.3 steel is popularly used to produce core unit of nuclear power reactors due to its outstanding ability of anti-neutron irradiation and good fracture toughness. The forging process takes important role in manufacturing to refine the grain size and improve the material properties. But due to their huge size, heavy forgings cannot be cooled down quickly, and the refined grains usually have long time to grow in high temperature conditions. If the forging process is not adequately scheduled or implemented, very large grains up to millimetres in size may be found in this steel and cannot be eliminated in the subsequent heat treatment. To fix the condition which may causes the coarsening of the steel, hot upsetting experiments in the industrial production environment were performed under different working conditions and the corresponding grain sizes were measured and analysed. The observation showed that the grain will abnormally grow if the deformation is less than a critical value. The strain energy takes a critical role in the grain evolution. If dynamic recrystallization consumes the strain energy as much as possible, the normal grains will be obtained. While if not, the stored strain energy will promote abnormal growth of the grains.

  14. Computer-assisted Rheo-forging Processing of A356 Aluminum Alloys

    Science.gov (United States)

    Kim, H. H.; Kang, C. G.

    2010-06-01

    Die casting process has been used widely for complex automotive products such as the knuckle, arm and etc. Generally, a part fabricated by casting has limited strength due to manufacturing defects by origin such as the dendrite structure and segregation. As an attempt to offer a solution to these problems, forging has been used as an alternative process. However, the forging process provides limited formability for complex shape products. Rheo-forging of metal offers not only superior mechanical strength but also requires significantly lower machine loads than solid forming processes. In order to produce semi-solid materials of the desired microstructure, a stirring process is applied during solidification of A356 aluminum molten state. This paper presents the results of an A356 aluminum alloy sample, which were obtained by experiment and by simulation using DEFORM 3D V6.1. Samples of metal parts were subsequently fabricated by using hydraulic press machinery. In order to compare the influence of loading method, two types of samples were fabricated: (1) samples fabricated under direct loading die sets (2) those fabricated under indirect loading die sets. The formability and defects, which were predicted by FEM simulation, were similar to those of samples used in practice.

  15. 2016 Accomplishments. Tritium aging studies on stainless steel. Forging process effects on the fracture toughness properties of tritium-precharged stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-01-01

    Forged austenitic stainless steels are used as the materials of construction for pressure vessels designed to contain tritium at high pressure. These steels are highly resistant to tritium-assisted fracture but their resistance can depend on the details of the forging microstructure. During FY16, the effects of forging strain rate and deformation temperature on the fracture toughness properties of tritium-exposed-and-aged Type 304L stainless steel were studied. Forgings were produced from a single heat of steel using four types of production forging equipment – hydraulic press, mechanical press, screw press, and high-energy-rate forging (HERF). Each machine imparted a different nominal strain rate during the deformation. The objective of the study was to characterize the J-Integral fracture toughness properties as a function of the industrial strain rate and temperature. The second objective was to measure the effects of tritium and decay helium on toughness. Tritium and decay helium effects were measured by thermally precharging the as-forged specimens with tritium gas at 34.5 MPa and 350°C and aging for up to five years at -80°C to build-in decay helium prior to testing. The results of this study show that the fracture toughness properties of the as-forged steels vary with forging strain rate and forging temperature. The effect is largely due to yield strength as the higher-strength forgings had the lower toughness values. For non-charged specimens, fracture toughness properties were improved by forging at 871°C versus 816°C and Screw-Press forgings tended to have lower fracture toughness values than the other forgings. Tritium exposures reduced the fracture toughness values remarkably to fracture toughness values averaging 10-20% of as-forged values. However, forging strain rate and temperature had little or no effect on the fracture toughness after tritium precharging and aging. The result was confirmed by fractography which indicated that fracture modes

  16. Choroidal thickness profile in healthy Indian children.

    Science.gov (United States)

    Chhablani, Jay Kumar; Deshpande, Riddhima; Sachdeva, Virender; Vidya, Sagar; Rao, P Srinivasa; Panigati, Anand; Mahat, Birendra; Pappuru, Rajeev Reddy; Pehere, Niranjan; Pathengay, Avinash

    2015-06-01

    The purpose was to study choroidal thickness and its profile based on location in healthy Indian children using enhanced depth spectral-domain-optical coherence tomography (SD-OCT). In this cross-sectional observational study 255 eyes of 136 children with no retinal or choroidal disease were consecutively scanned using enhanced depth SD-OCT. Eyes with any ocular disease or axial length (AXL) >25 mm or choroidal thickness from the posterior edge of the retinal pigment epithelium to the choroid/sclera junction at 500-microns intervals up to 2500 microns temporal and nasal to the fovea. Generalized estimating equations were used to evaluate the correlation between choroidal thickness at various locations and age, AXL, gender and spherical equivalent (SEq). Mean age of the subjects was 11.9 ± 3.4 years (range: 5-18 years). There were 62 Females and 74 males. The mean AXL was 23.55 ± 0.74 mm. Mean subfoveal choroidal thickness was 312.1 ± 45.40 μm. Choroid was found to be thickest subfoveally, then temporally. Age, AXL and SEq showed a significant correlation with choroidal thickness, whereas gender did not affect choroidal thickness. Our study provides a valid normative database of choroidal thickness in healthy Indian children. This database could be useful for further studies evaluating choroidal changes in various chorioretinal disorders. Age and AXL are critical factors, which negatively correlated with choroidal thickness.

  17. Roadway support technique with large section and composite roof in thick coal seam%特厚煤层大断面复合顶板煤巷支护技术

    Institute of Scientific and Technical Information of China (English)

    袁胜军; 李二鹏; 郑阳; 龚爽; 王金光; 李世俊

    2015-01-01

    针对某矿辅助运输大巷变形严重、返修量大的支护难题,对巷道顶板复合结构变形机制进行了力学分析,揭示出巷道顶部锚固层厚度、顶板软弱夹层与锚固区相对位置及锚杆(索)预应力是影响此类巷道稳定的重要因素;运用FLAC3D数值模拟软件对不同支护参数的控制效果进行了研究,结合现场生产地质条件综合确定了“高强高预应力锚杆(索)+金属网+W型钢带+喷射混凝土”联合支护方案。现场实践表明,巷道顶底板移近量以及两帮移近量明显减少,围岩变形得到了有效的控制。%In order to solve the support problems of the auxiliary haulage roadway ,such as large deformation and frequent rework ,we revealed the roadway stability influence factors that are anchored thickness ,relative positional relation of weak interlayer and anchorage area and anchor cable pre‐stress by means of the mechanical stability analysis of deformation mechanism in the composite structure above roof . Furthermore ,we researched the control effect with different parameters aided by FLAC3D .In addition , combined with field production and geological conditions ,we finally proposed the collaborative support program consists of high strength and high pre‐stressed anchor (cable) ,metal mesh ,W steel trips and concrete injection .The field practice shows that deformation amount of roof ,floor and two sides in roadway obviously decreased ,which indicates the effective control of the roadway surrounding rock deformation .

  18. Common carotid intima media thickness and ankle-brachial pressure index correlate with local but not global atheroma burden: a cross sectional study using whole body magnetic resonance angiography.

    Directory of Open Access Journals (Sweden)

    Jonathan R Weir-McCall

    Full Text Available Common carotid intima media thickness (CIMT and ankle brachial pressure index (ABPI are used as surrogate marker of atherosclerosis, and have been shown to correlate with arterial stiffness, however their correlation with global atherosclerotic burden has not been previously assessed. We compare CIMT and ABPI with atheroma burden as measured by whole body magnetic resonance angiography (WB-MRA.50 patients with symptomatic peripheral arterial disease were recruited. CIMT was measured using ultrasound while rest and exercise ABPI were performed. WB-MRA was performed in a 1.5T MRI scanner using 4 volume acquisitions with a divided dose of intravenous gadolinium gadoterate meglumine (Dotarem, Guerbet, FR. The WB-MRA data was divided into 31 anatomical arterial segments with each scored according to degree of luminal narrowing: 0 = normal, 1 = <50%, 2 = 50-70%, 3 = 70-99%, 4 = vessel occlusion. The segment scores were summed and from this a standardized atheroma score was calculated.The atherosclerotic burden was high with a standardised atheroma score of 39.5±11. Common CIMT showed a positive correlation with the whole body atheroma score (β 0.32, p = 0.045, however this was due to its strong correlation with the neck and thoracic segments (β 0.42 p = 0.01 with no correlation with the rest of the body. ABPI correlated with the whole body atheroma score (β -0.39, p = 0.012, which was due to a strong correlation with the ilio-femoral vessels with no correlation with the thoracic or neck vessels. On multiple linear regression, no correlation between CIMT and global atheroma burden was present (β 0.13 p = 0.45, while the correlation between ABPI and atheroma burden persisted (β -0.45 p = 0.005.ABPI but not CIMT correlates with global atheroma burden as measured by whole body contrast enhanced magnetic resonance angiography in a population with symptomatic peripheral arterial disease. However this is

  19. Design and Improve Forging Mould of Squareness Bol%方头螺栓的锻造模具的设计与改进

    Institute of Scientific and Technical Information of China (English)

    连厚富; 齐永丰

    2014-01-01

    通过对方头螺栓胎模锻与自由锻优点的比较,介绍了通过充分利用胎模来生产锻件,可达到不断降低锻件毛坯重量,减少加工工时目的。设计合理的锻膜结构和不断改进锻模结构,是该工艺的关键。%By comparing the advantages between loose tooling forging with the free forging on forging square-head bolt , it is introduced that by utilizing membranes to produce forging can achieve forging blank to decrease weight and reduce the processing time . Reasonable design of forging die structure , mem-brane structure and the continuous improvement is the key to this process .

  20. Influence on the quality of forgings long-axis heavy forgings in squaring process%压方圆角对长轴类大锻件质量影响研究

    Institute of Scientific and Technical Information of China (English)

    李光喜; 吴玉忠; 郭扬

    2015-01-01

    According to the characteristics of long-axis heavy forgings.The whole forging process of longaxis heavy forging was divided into three steps,including squaring,stretching and chamfering rounding.Researches of forging process are now focused on the optimization of stretching,but hardly on forging process optimization.By means of DEFORM-3D software,edge radius of V-shaped anvil were simulated and optimized from aspects of internal stress state,stress and the damage factor in squaring process.Results of Simulation show that appropriate edge radius of V-shaped anvil can prevent forging cracks and improve the quality of forgings.%长轴类大锻件的锻造过程一般分为压方、拔长和倒棱滚圆三大步骤,目前对锻造工艺研究较多的是拔长和倒棱滚圆的优化,很少有对压方工艺优化的研究。本文从V型砧边缘的圆角半径的大小来对长轴类大锻件的压方过程进行模拟优化,从锻件内部应力、应变及破坏因子三个方面进行对比分析。结果表明,适当增大V型砧边缘的圆角半径可以有效防止锻件裂纹的产生,为锻件的质量提高和结构设计提供一种有效、可靠的分析方法。

  1. 平锻机锻件缺陷分析及对策%Failure analysis and solution of forging parts manufactured by horizontal forging machine

    Institute of Scientific and Technical Information of China (English)

    张国杰

    2013-01-01

    Taking the 1250T horizontal forging machine as an example, the process characteristics of this machine have been introduced in the text. The failures like poor straightness of rod, pad injury, folding and mismatch of tool in the daily production have been analyzed and the solution has been put forward.%结合公司1250t平锻机,介绍此种设备生产锻件工艺特点,并对日常生产中遇到的杆部直线度超差、垫伤、折叠及错模等锻件缺陷进行分析并提出解决办法.

  2. Forging the link between nuclear reactions and nuclear structure.

    Science.gov (United States)

    Mahzoon, M H; Charity, R J; Dickhoff, W H; Dussan, H; Waldecker, S J

    2014-04-25

    A comprehensive description of all single-particle properties associated with the nucleus Ca40 is generated by employing a nonlocal dispersive optical potential capable of simultaneously reproducing all relevant data above and below the Fermi energy. The introduction of nonlocality in the absorptive potentials yields equivalent elastic differential cross sections as compared to local versions but changes the absorption profile as a function of angular momentum suggesting important consequences for the analysis of nuclear reactions. Below the Fermi energy, nonlocality is essential to allow for an accurate representation of particle number and the nuclear charge density. Spectral properties implied by (e, e'p) and (p, 2p) reactions are correctly incorporated, including the energy distribution of about 10% high-momentum nucleons, as experimentally determined by data from Jefferson Lab. These high-momentum nucleons provide a substantial contribution to the energy of the ground state, indicating a residual attractive contribution from higher-body interactions for Ca40 of about 0.64  MeV/A.

  3. Effect of forging parameters on low cycle fatigue behaviour of Al/basalt short fiber metal matrix composites.

    Science.gov (United States)

    Karthigeyan, R; Ranganath, G

    2013-01-01

    This paper deals with metal matrix composites (MMCs) of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10) basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0 wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10 weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface.

  4. Computer-Aided Design of Manufacturing Chain Based on Closed Die Forging for Hardly Deformable Cu-Based Alloys

    Science.gov (United States)

    Pietrzyk, Maciej; Kuziak, Roman; Pidvysots'kyy, Valeriy; Nowak, Jarosław; Węglarczyk, Stanisław; Drozdowski, Krzysztof

    2013-07-01

    Two copper-based alloys were considered, Cu-1 pct Cr and Cu-0.7 pct Cr-1 pct Si-2 pct Ni. The thermal, electrical, and mechanical properties of these alloys are given in the paper and compared to pure copper and steel. The role of aging and precipitation kinetics in hardening of the alloys is discussed based upon the developed model. Results of plastometric tests performed at various temperatures and various strain rates are presented. The effect of the initial microstructure on the flow stress was investigated. Rheologic models for the alloys were developed. A finite element (FE) model based on the Norton-Hoff visco-plastic flow rule was applied to the simulation of forging of the alloys. Analysis of the die wear for various processes of hot and cold forging is presented as well. A microstructure evolution model was implemented into the FE code, and the microstructure and mechanical properties of final products were predicted. Various variants of the manufacturing cycles were considered. These include different preheating schedules, hot forging, cold forging, and aging. All variants were simulated using the FE method and loads, die filling, tool wear, and mechanical properties of products were predicted. Three variants giving the best combination of forging parameters were selected and industrial trials were performed. The best manufacturing technology for the copper-based alloys is proposed.

  5. Influence of die geometry and material selection on the behavior of protective die covers in closed-die forging

    Science.gov (United States)

    Yu, Yingyan; Rosenstock, Dirk; Wolfgarten, Martin; Hirt, Gerhard

    2016-10-01

    Due to the fact that tooling costs make up to 30% of total costs of the final forged part, the tool life is always one main research topic in closed-die forging [1]. To improve the wear resistance of forging dies, many methods like nitriding and deposition of ceramic layers have been used. However, all these methods will lose its effect after a certain time, then tool repair or exchange is needed, which requires additional time and costs. A new method, which applies an inexpensive and changeable sheet metal on the forging die to protect it from abrasive wear, was firstly proposed in [2]. According to the first investigation, the die cover is effective for decreasing thermal and mechanical loads, but there are still several challenges to overcome in this concept, like wrinkling and thinning of the die cover. Therefore, an experimental study using different geometries and die cover materials is presented within this work. The results indicate the existence of feasible application cases of this concept, since conditions are found under which a die cover made of 22MnB5 still keeps its original shape even after 7 forging cycles.

  6. Production of A356 aluminum alloy wheels by thixo-forging combined with a low superheat casting process

    Directory of Open Access Journals (Sweden)

    Wang Shuncheng

    2013-09-01

    Full Text Available The A356 aluminum alloy wheels were produced by thixo-forging combined with a low superheat casting process. The as-cast microstructure, microstructure evolution during reheating and the mechanical properties of thixo-forged wheels made from the A356 aluminum alloy were studied. The results show that the A356 aluminum alloy round billet with fine, uniform and non-dendritic grains can be obtained when the melt is cast at 635 篊. When the round billet is reheated at 600 篊 for 60 min, the non-dendritic grains are changed into spherical ones and the round billet can be easily thixo-forged into wheels. The tensile strength, yield strength and elongation of the thixo-forged wheels with T6 heat treatment are 327.6 MPa, 228.3 MPa and 7.8%, respectively, which are higher than those of a cast wheel. It is suggested that the thixo-forging combined with the low superheat casting process is an effective technique to produce aluminum alloy wheels with high mechanical properties.

  7. Effects of Low Temperature on Hydrogen-Assisted Crack Growth in Forged 304L Austenitic Stainless Steel

    Science.gov (United States)

    Jackson, Heather; San Marchi, Chris; Balch, Dorian; Somerday, Brian; Michael, Joseph

    2016-08-01

    The objective of this study was to evaluate effects of low temperature on hydrogen-assisted crack propagation in forged 304L austenitic stainless steel. Fracture initiation toughness and crack-growth resistance curves were measured using fracture mechanics specimens that were thermally precharged with 140 wppm hydrogen and tested at 293 K or 223 K (20 °C or -50 °C). Fracture initiation toughness for hydrogen-precharged forgings decreased by at least 50 to 80 pct relative to non-charged forgings. With hydrogen, low-temperature fracture initiation toughness decreased by 35 to 50 pct relative to room-temperature toughness. Crack growth without hydrogen at both temperatures was microstructure-independent and indistinguishable from blunting, while with hydrogen microcracks formed by growth and coalescence of microvoids. Initiation of microvoids in the presence of hydrogen occurred where localized deformation bands intersected grain boundaries and other deformation bands. Low temperature additionally promoted fracture initiation at annealing twin boundaries in the presence of hydrogen, which competed with deformation band intersections and grain boundaries as sites of microvoid formation and fracture initiation. A common ingredient for fracture initiation was stress concentration that arose from the intersection of deformation bands with these microstructural obstacles. The localized deformation responsible for producing stress concentrations at obstacles was intensified by low temperature and hydrogen. Crack orientation and forging strength were found to have a minor effect on fracture initiation toughness of hydrogen-supersaturated 304L forgings.

  8. Forging the link between nuclear reactions and nuclear structure

    Science.gov (United States)

    Dickhoff, W. H.

    2016-06-01

    A review of the recent applications of the dispersive optical model (DOM) is presented. Emphasis is on the nonlocal implementation of the DOM that is capable of describing ground-state properties accurately when data like the nuclear charge density are available. The present understanding of the role of short- and long-range physics in determining proton properties near the Fermi energy for stable closed-shell nuclei has relied mostly on data from the (e, e' p) reaction. Hadronic tools to extract such spectroscopic information have been hampered by the lack of a consistent reaction description that provides unambiguous and undisputed results. The DOM, conceived by Claude Mahaux, provides a unified description of both elastic nucleon scattering and structure information related to single-particle properties below the Fermi energy. We have recently introduced a nonlocal dispersive optical potential for both the real and imaginary part. Nonlocal absorptive potentials yield equivalent elastic differential cross sections for 40Ca as compared to local ones but change the l-dependent absorption profile suggesting important consequences for the analysis of nuclear reactions. Below the Fermi energy, nonlocality is essential for an accurate representation of particle number and the nuclear charge density. Spectral properties implied by (e, e' p) and (p, 2p) reactions are correctly described, including the energy distribution of about 10% high-momentum protons obtained at Jefferson Lab. The nonlocal DOM allows a complete description of experimental data both above (up to 200 MeV) and below the Fermi energy in 40Ca. It is further demonstrated that elastic nucleon-nucleus scattering data constrain the spectral strength in the continuum of orbits that are nominally bound in the independent-particle model. Extension of this analysis to 48Ca allows a prediction of the neutron skin of this nucleus that is larger than most predictions made so far.

  9. Forging the link between nuclear reactions and nuclear structure

    Directory of Open Access Journals (Sweden)

    Dickhoff W. H.

    2016-01-01

    Full Text Available A review of the recent applications of the dispersive optical model (DOM is presented. Emphasis is on the nonlocal implementation of the DOM that is capable of describing ground-state properties accurately when data like the nuclear charge density are available. The present understanding of the role of short- and long-range physics in determining proton properties near the Fermi energy for stable closed-shell nuclei has relied mostly on data from the (e, e′ p reaction. Hadronic tools to extract such spectroscopic information have been hampered by the lack of a consistent reaction description that provides unambiguous and undisputed results. The DOM, conceived by Claude Mahaux, provides a unified description of both elastic nucleon scattering and structure information related to single-particle properties below the Fermi energy. We have recently introduced a nonlocal dispersive optical potential for both the real and imaginary part. Nonlocal absorptive potentials yield equivalent elastic differential cross sections for 40Ca as compared to local ones but change the l-dependent absorption profile suggesting important consequences for the analysis of nuclear reactions. Below the Fermi energy, nonlocality is essential for an accurate representation of particle number and the nuclear charge density. Spectral properties implied by (e, e′ p and (p, 2p reactions are correctly described, including the energy distribution of about 10% high-momentum protons obtained at Jefferson Lab. The nonlocal DOM allows a complete description of experimental data both above (up to 200 MeV and below the Fermi energy in 40Ca. It is further demonstrated that elastic nucleon-nucleus scattering data constrain the spectral strength in the continuum of orbits that are nominally bound in the independent-particle model. Extension of this analysis to 48Ca allows a prediction of the neutron skin of this nucleus that is larger than most predictions made so far.

  10. B-test in late pregnancy on the thickness of the lower uterine segment cesarean section scar significance%B超检测妊娠晚期子宫下段瘢痕厚度对再次剖宫产的意义

    Institute of Scientific and Technical Information of China (English)

    张春风

    2014-01-01

    Objective To investigate the B-test trimester uterine segment cesarean section scar vicious value again. Methods In accordance with scar thickness is<3mm, 94 cases of cesarean section will be divided into maternal<3mm group and ≥ 3mm each group 47 cases. Comparison of two blood loss, the number of cases of postpartum hemorrhage and oxytocin usage to re-evaluation of the value of B-test cesarean scar thickness. Results <3mm group blood loss was 336.9 ± 118.4mL, the number of cases of postpartum hemorrhage in 9 cases (19.15%), oxytocin usage was 90.1±18.7 U, significantly higher than the index≥3mm group(P<0.05). Conclusion B-test scar thickness can effectively guide cesarean section has important clinical significance.%目的:探讨B超检测妊娠晚期子宫下段瘢痕厚度对再次剖宫产的价值。方法将94例再次剖宫产孕产妇按照子宫下段瘢痕厚度分为<3 mm组和≥3 mm组各47例,比较2组术中出血量、产后出血例数和缩宫素使用量,以评价B超检测瘢痕厚度对再次剖宫产的价值。结果<3 mm组术中出血量为(336.9±118.4)mL,产后出血例数有9例(19.15%),缩宫素使用量为(90.1±18.7)U,均明显高于≥3 mm组(P<0.01)。结论通过B超检测子宫瘢痕厚度可以有效地指导再次剖宫产,具有重要的临床意义。

  11. 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.

  12. Derivation of uranium residual radioactive material guidelines for the Aliquippa Forge site

    Energy Technology Data Exchange (ETDEWEB)

    Monette, F.; Jones, L.; Yu, C.

    1992-09-01

    Residual radioactive material guidelines for uranium were derived for the Aliquippa Forge site in Aliquippa, Pennsylvania. This site has been identified for remedial action under the Formerly Utilized Sites Remedial Action Program (FUSRAP) of the US Department of Energy (DOE). The uranium guidelines were derived on the basis of the requirement that the 50-year committed effective dose equivalent to a hypothetical individual who lives or works in the immediate vicinity of the Aliquippa Forge site should not exceed a dose of 100 mrem/yr following decontamination. The DOE residual radioactive material guideline computer code, RESRAD, which implements the methodology described in the DOE manual for implementing residual radioactive material guidelines, was used in this evaluation. Four potential scenarios were considered for the site; the scenarios vary with regard to time spent at the site, sources of water used, and sources of food consumed. The results of the evaluation indicate that the basic dose limit of 100 mrem/yr will not be exceeded for uranium within 1,000 years, provided that the soil concentration of combined uranium (uranium-234, uranium-235, and uranium-238) at the Aliquippa Forge site does not exceed the following levels: 1,700 pCi/g for Scenario A (industrial worker: the expected scenario); 3,900 pCi/g for Scenario B (recreationist: a plausible scenario); 20 pCi/g for Scenario C (resident farmer using well water as the only water source: a possible but unlikely scenario), and 530 pCi/g for Scenario D (resident farmer using a distant water source not affected by site conditions as the only water source: a possible but unlikely scenario). The uranium guidelines derived in this report apply to the combined activity concentration of uranium-234, uranium-235, and uranium-238 and were calculated on the basis of a dose of 100 mrem/yr.

  13. Energy-efficiency in inductive heating of forging ingots; Energieeffizienz bei der induktiven Erwaermung von Schmiedebloecken

    Energy Technology Data Exchange (ETDEWEB)

    Padberg, Michael; Doetsch, Erwin [ABP Induction Systems, Dortmund (Germany)

    2012-03-15

    The continuously increasing importance of the CO{sub 2} balance and of conservation of resources is resulting in ever greater demands for high energy-efficiency in the process used for heating of forging ingots. Plant and process engineering play roles of parallel significance in the fulfillment of these requirements, and this article focuses on both in equal degree. The shares of the individual components in the overall energy consumption of an induction heating installation are therefore firstly determined, and their respective potentials for optimization then discussed. The quality of the heating process itself, and its optimum design for reduction of energy consumption, are then examined. (orig.)

  14. Influence of the milling strategy on the durability of forging tools

    OpenAIRE

    Ficko, Mirko; Balič, Jože; Gotlih, Karl; Pahole, Ivo; Studenčnik, Dejan

    2015-01-01

    The quality of a tool's surface has a direct influence on the number of well-produced parts. For the machining of an active tool surface, two technological processes are used: electrical discharge machining and high-speed milling. These two processes are used when machining new tools and for the repairing of used forging tools. In both cases, the material has already been thermally treated, so it has to be used for hard milling. Practical experience shows that the milling strategy has a big i...

  15. Forging partnerships between rural women with chronic conditions and their health care providers.

    Science.gov (United States)

    Cudney, Shirley; Weinert, Clarann; Kinion, Elizabeth

    2011-03-01

    Successful adaptation to chronic illness is enhanced by active client-health care provider partnerships. The purposes of this article are to (a) examine the health care partnership needs of western rural women with chronic illness who participated in a computer-based support and education project, (b) describe how the role of the women in the partnership can be maximized by the use of a personal health record and improving health literacy, and (c) discuss ways health care providers can enhance their role in the partnership by careful listening and creating environments conducive to forging productive client-provider partnerships.

  16. The Development Of Heating Curves For Open Die Forging Of Heavy Parts

    Directory of Open Access Journals (Sweden)

    Gołdasz A.

    2015-09-01

    Full Text Available The study presents the findings of research on developing heating curves of heavy parts for the open die forging process. Hot ingots are heated in a chamber furnace. The heating process of 10, 30, 50 Mg ingots was analyzed. In addition, bearing in mind their high susceptibility to fracture, the ingots were sorted into 3 heating groups, for which the initial furnace temperature was specified. The calculations were performed with self developed software Wlewek utilizing the finite element method for the temperature, stress and strain field computations.

  17. New lubricant systems for cold and warm forging – advantages and limitations

    DEFF Research Database (Denmark)

    Bay, Niels

    2011-01-01

    The increasing focus on environmental issues and the requirements to establish solutions diminishing the impact on working environment as well as external environment has strongly motivated the efforts to develop new, environmentally friendly tribological systems for metal forming production....... The present paper gives an overview of these efforts substituting environmentally hazardous lubricants in cold, warm and hot forging by new, more harmless lubricants. Introduction of these new lubricants, however, has some drawbacks due to lower limits of lubrication leading to risk of pick-up, poor product...

  18. Consolidation of nanostructured metal powders by rapid forging: Processing, modeling, and subsequent mechanical behavior

    Science.gov (United States)

    Shaik, G. R.; Milligan, W. W.

    1997-03-01

    Fe-10Cu powders containing 20-nm grains were produced by attritor milling of elemental powders in argon. A rapid powder forging technique was developed to consolidate the powders into fully dense compacts while maintaining nanoscale grain sizes. Grain growth during the consolidation was controlled by reducing the time of exposure at elevated temperature to a few minutes or less, a technique which is applicable to all materials and does not necessitate the addition of dispersoids. This was achieved by heating green compacts quickly using an induction heater, and then forging and rapidly cooling them back to room temperature. Forging was conducted in a protective argon atmosphere to limit contamination. Fully dense compacts were produced at relatively low temperatures, mainly due to the accelerated creep rates exhibited by the nanostructures. Transmission electron microscopy and X-ray diffraction analysis found an average grain size of 45 nm in the fully dense samples forged at 530°C. Indications are that finer grain sizes should be attainable by using slightly lower temperatures and higher pressures. The success of the technique (compared to hot-isostatic pressing (“hipping”)) is due to both reducing time at elevated temperatures and applying relatively high pressures. Microhardness tests revealed a significant strengthening effect due to grain size refinement, following a Hall-Petch relation. Compression testing at room temperature showed no strain hardening during plastic deformation, which occurred by shear banding. High strengths, up to 1800 MPa, were obtained at room temperature. Compression testing at 575°C revealed a significant strain rate dependence of mechanical behavior and also the possibility of superplastic behavior. Power-law creep was observed at 575°C, with very high steady-state creep rates on the order of 50 pct/s at 230 MPa. The consolidation process was successfully modeled by slightly modifying and applying the Arzt, Ashby, and

  19. Open die forging of large shafts with porosity defects – physical and numerical modelling

    DEFF Research Database (Denmark)

    Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

    2013-01-01

    The aim and scope of this paper is centered to analyze the influence of the geometry of V-shaped dies on the closure of internal centerline porosity defects in ingots during multistep open-die forging. The investigation is performed with small scale physical models made from lead using V-shaped d...... conditions. The presentation is supported by finite element modelling using an in-house developed computer program and the overall investigation shows that better results in closure of centerline defects are obtained with a V-shaped die with 120º die angle....

  20. Tribological Investigations of Hard-Faced Layers and Base Materials of Forging Dies with Different Kinds of Lubricants Applied

    Directory of Open Access Journals (Sweden)

    V. Lazić

    2010-12-01

    Full Text Available This paper gives a procedure for choosing the right technology for reparative hard facing of damaged forging dies. Since they are subject to impact loads and cyclic temperature elevations, forging dies should be made of steel that is able to withstand great impact loads, maintain good mechanical properties at elevated temperatures and that is resistant to wear and thermal fatigue. For these reasons, forging dies are made of conditionally weldable alloy tool steels; however it makes hard facing of damaged tools even more difficult. In this paper, wear resistance of base materials, hard-faced layers and heat-affected zones are tribologically investigated when two different lubricants - pure synthetical oil LM 76 and LM 76 with 6% molybdenum disulfide (MoS2 are applied. Tribological investigations have shown that the wear resistance of the hard faced layers is considerably greater than the wear resistance of the base material. However, the base material has better properties concerning friction.

  1. Investigations into Deformation Characteristics during Open-Die Forging of SiCp Reinforced Aluminium Metal Matrix Composites

    Directory of Open Access Journals (Sweden)

    Deep Verma

    2013-01-01

    Full Text Available The deformation characteristics during open-die forging of silicon carbide particulate reinforced aluminium metal matrix composites (SiCp AMC at cold conditions are investigated. The material was fabricated by liquid stir casting method in which preheated SiC particles were mixed with molten LM6 aluminium casting alloy and casted in the silicon mould. Finally, preforms obtained were machined in required dimensions. Two separate cases of deformation, that is, open-die forging of solid disc and solid rectangular preforms, were considered. Both upper bound theoretical analysis and experimental investigations were performed followed by finite element simulation using DEFORM, considering composite interfacial friction law, barreling of preform vertical sides, and inertia effects, that is, effect of die velocity on various deformation characteristics like effective stress, strain, strain rate, forging load, energy dissipations, and height reduction. Results have been presented graphically and critically investigated to evaluate the concurrence among theoretical, experimental, and finite element based computational findings.

  2. Effects of boron additions and solutionizing treatments on microstructures and ductility of forged Ti–6Al–4V alloys

    Energy Technology Data Exchange (ETDEWEB)

    Luan, J.H.; Jiao, Z.B. [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, College of Science and Engineering, City University of Hong Kong, Hong Kong (China); Chen, G. [Engineering Research Center of Materials Behavior and Design, Ministry of Education, Nanjing University of Science and Technology, Nanjing 210094 (China); Liu, C.T., E-mail: chainliu@cityu.edu.hk [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, College of Science and Engineering, City University of Hong Kong, Hong Kong (China)

    2015-03-05

    Highlights: • Proper boron additions and heat-treatments improve the ductility of Ti64 alloys. • Coarse TiB precipitates embrittle the Ti64 alloys causing ductility loss. • Modified Ti64 forged alloys with high strength and high ductility are developed. - Abstract: The effects of boron additions on the microstructure and mechanical properties of forged Ti–6Al–4V alloys in different heat-treatment conditions have been characterized by both experimental studies and thermodynamic calculations. The results indicate a combination of proper post-forging treatments and B additions are helpful for control of the prior-β grain size and the volume fraction of α phase, thereby tuning the ductility of the forged Ti–6Al–4V alloys. However, the B-containing alloys exhibit a significant drop in ductility if the solutionizing temperature is too high, and this embrittlement is mainly due to the coarsening of brittle TiB borides. The mechanism in this case is due to the cleavage fracture of TiB rather than its debonding with the matrix, as indicated by the observation of the aligned TiB borides on the matching areas of both halves of the fracture surfaces. Thus, the TiB size and orientation, the prior-β grain size, and the volume fraction of the α phase all play important roles in controlling the mechanical properties of the forged Ti–6Al–4V alloys. The current findings shed light on the composition–microstructure–ductility relationship in the forged Ti–6Al–4V alloys.

  3. STEM tomography for thick biological specimens

    Energy Technology Data Exchange (ETDEWEB)

    Aoyama, Kazuhiro [FEI Company Japan Ltd., Application Laboratory, NSS-II Building, 2-13-34 Kohnan, Minato-ku, Tokyo 108-0075 (Japan)], E-mail: kazuhiro.aoyama@fei.com; Takagi, Tomoko [FEI Company Japan Ltd., Application Laboratory, NSS-II Building, 2-13-34 Kohnan, Minato-ku, Tokyo 108-0075 (Japan); Laboratory of Electron Microscopy, Japan Women' s University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681 (Japan); Hirase, Ai; Miyazawa, Atsuo [Bio-multisome Research Team, RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); CREST, JST (Japan)

    2008-12-15

    Scanning transmission electron microscopy (STEM) tomography was applied to biological specimens such as yeast cells, HEK293 cells and primary culture neurons. These cells, which were embedded in a resin, were cut into 1-{mu}m-thick sections. STEM tomography offers several important advantages including: (1) it is effective even for thick specimens, (2) 'dynamic focusing', (3) ease of using an annular dark field (ADF) mode and (4) linear contrasts. It has become evident that STEM tomography offers significant advantages for the observation of thick specimens. By employing STEM tomography, even a 1-{mu}m-thick specimen (which is difficult to observe by conventional transmission electron microscopy (TEM)) was successfully analyzed in three dimensions. The specimen was tilted up to 73 deg. during data acquisition. At a large tilt angle, the specimen thicknesses increase dramatically. In order to observe such thick specimens, we introduced a special small condenser aperture that reduces the collection angle of the STEM probe. The specimen damage caused by the convergent electron beam was expected to be the most serious problem; however, the damage in STEM was actually smaller than that in TEM. In this study, the irradiation damage caused by TEM- and STEM-tomography in biological specimens was quantitatively compared.

  4. Cesarean Sections

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Cesarean Sections (C-Sections) KidsHealth > For Parents > Cesarean Sections (C-Sections) A A A What's in this ... babies in the United States are delivered via cesarean section (C-section). Even if you're envisioning a ...

  5. Selection of the optimal hard facing (HF technology of damaged forging dies based on cooling time t8/5

    Directory of Open Access Journals (Sweden)

    D. Arsić

    2016-01-01

    Full Text Available In exploitation, the forging dies are exposed to heating up to very high temperatures, variable loads: compressive, impact and shear. In this paper, the reparatory hard facing of the damaged forging dies is considered. The objective was to establish the optimal reparatory technology based on cooling time t8/5 . The verification of the adopted technology was done by investigation of the hard faced layers microstructure and measurements of hardness within the welded layers’ characteristic zones. Cooling time was determined theoretically, numerically and experimentally.

  6. Experimental Research on the SizeMeasurement of the High Temperature ForgingBased on Multicolor CCD Technology

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    In order to determine the size measurement accuracy of the high temperature forging's multicolor CCD image by using computerprograms, this paper obtained the high temperature forging's CCD image by multicolor CCD camera and its fact size by thevernier caliper on the forging field, and then measured the size of the high temperature forging from its CCD image, compared thesize from the CCD image and the size from the vernier caliper, the result shows that the measurement accuracy satisfied theindustrial production.

  7. Choroidal thickness profile in healthy Indian children

    Directory of Open Access Journals (Sweden)

    Jay Kumar Chhablani

    2015-01-01

    Full Text Available Purpose: The purpose was to study choroidal thickness and its profile based on location in healthy Indian children using enhanced depth spectral-domain-optical coherence tomography (SD-OCT. Methods: In this cross-sectional observational study 255 eyes of 136 children with no retinal or choroidal disease were consecutively scanned using enhanced depth SD-OCT. Eyes with any ocular disease or axial length (AXL >25 mm or < 20 mm were excluded. A single observer measured choroidal thickness from the posterior edge of the retinal pigment epithelium to the choroid/sclera junction at 500-microns intervals up to 2500 microns temporal and nasal to the fovea. Generalized estimating equations were used to evaluate the correlation between choroidal thickness at various locations and age, AXL, gender and spherical equivalent (SEq. Results: Mean age of the subjects was 11.9 ± 3.4 years (range: 5-18 years. There were 62 Females and 74 males. The mean AXL was 23.55 ± 0.74 mm. Mean subfoveal choroidal thickness was 312.1 ± 45.40 μm. Choroid was found to be thickest subfoveally, then temporally. Age, AXL and SEq showed a significant correlation with choroidal thickness, whereas gender did not affect choroidal thickness. Conclusion: Our study provides a valid normative database of choroidal thickness in healthy Indian children. This database could be useful for further studies evaluating choroidal changes in various chorioretinal disorders. Age and AXL are critical factors, which negatively correlated with choroidal thickness.

  8. Study on Pot Forming of Induction Heater Type Rice Cookers by Forging Cast Process

    Science.gov (United States)

    Ohnishi, Masayuki; Yamaguchi, Mitsugi; Ohashi, Osamu

    This paper describes a study result on pot fabrication by the forging cast process of stainless steel with aluminum. Rice cooked with the new bowl-shaped pot for the induction heater type rice cookers is better tasting than rice cooked with the conventional cylindrical one, due to the achievement of better heat conduction and convection. The conventional pot is made of the clad sheet, consisting of stainless steel and aluminum. However, it is rather difficult to form a bowl shape from the clad sheet, primarily due to the problem of a material spring back. The fabrication of a new type of a pot was made possible by means of the adoption of a forging cast process instead of the clad sheet. In this process, iron powder is inserted between stainless steel and aluminum in order to alleviate the large difference on the coefficient of expansion between each material. It was made clear that the application of two kinds of iron particle, namely 10 μm size powder on the stainless steel side and 44 μm on the aluminum side, enables the joints to become strong enough. The joint strength of the new pot by this fabrication process was confirmed by the tests of the shear strength and the fatigue tests together with the stress analysis.

  9. Forging tool shape optimization using pseudo inverse approach and adaptive incremental approach

    Science.gov (United States)

    Halouani, A.; Meng, F. J.; Li, Y. M.; Labergère, C.; Abbès, B.; Lafon, P.; Guo, Y. Q.

    2013-05-01

    This paper presents a simplified finite element method called "Pseudo Inverse Approach" (PIA) for tool shape design and optimization in multi-step cold forging processes. The approach is based on the knowledge of the final part shape. Some intermediate configurations are introduced and corrected by using a free surface method to consider the deformation paths without contact treatment. A robust direct algorithm of plasticity is implemented by using the equivalent stress notion and tensile curve. Numerical tests have shown that the PIA is very fast compared to the incremental approach. The PIA is used in an optimization procedure to automatically design the shapes of the preform tools. Our objective is to find the optimal preforms which minimize the equivalent plastic strain and punch force. The preform shapes are defined by B-Spline curves. A simulated annealing algorithm is adopted for the optimization procedure. The forging results obtained by the PIA are compared to those obtained by the incremental approach to show the efficiency and accuracy of the PIA.

  10. A Study On The Fabrication Of Iron Powder From Forging Scale Using Hydrogen

    Directory of Open Access Journals (Sweden)

    Shin S.M.

    2015-06-01

    Full Text Available This study was conducted to investigate the effect of hydrogen content, temperature, reaction time for the reduction of forging scale which is mainly composed of hematite (Fe2O3. All reductive reactions were performed over the temperature range of 700 to 1200°C as well as 0.1 to 1 atm of hydrogen partial pressures. The results showed that the mechanism for the reduction of iron oxides using hydrogen gas was not a simple process, but proceeded in multiple reduction stages thermodynamically. The iron oxide was almost completely reduced to metallic iron powder with 91 wt.% of iron content in the forging scale at 0.1 atm of hydrogen partial pressure. The content of iron was however found to be increased with increasing hydrogen partial pressure from 0.1 to 1 atm with regardless of temperatures. The metallic iron powder was obtained with the mean size of 100 μm and more porous structure was observed.

  11. Standard method of macroetch testing steel bars, billets, blooms, and forgings

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 Macroetching, which is the etching of specimens for macrostructural examination at low magnifications, is a frequently used technique for evaluating steel products such as bars, billets, blooms, and forgings. 1.2 Included in this method is a procedure for rating steel specimens by a graded series of photographs showing the incidence of certain conditions. The method is limited in application to bars, billets, blooms, and forgings of carbon and low alloy steels. 1.3 A number of different etching reagents may be used depending upon the type of examination to be made. Steels react differently to etching reagents because of variations in chemical composition, method of manufacture, heat treatment and many other variables. Establishment of general standards for acceptance or rejection for all conditions is impractical as some conditions must be considered relative to the part in which it occurs. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is ...

  12. A Method For Producing Hollow Shafts By Rotary Compression Using A Specially Designed Forging Machine

    Directory of Open Access Journals (Sweden)

    Tomczak J.

    2015-09-01

    Full Text Available The paper presents a new method for manufacturing hollow shafts, where tubes are used as billet. First, the design of a specially designed forging machine for rotary compression is described. The machine is then numerically tested with regard to its strength, and the effect of elastic strains of the roll system on the quality of produced parts is determined. The machine’s strength is calculated by the finite element method using the NX Nastran program. Technological capabilities of the machine are determined, too. Next, the results of the modeling of the rotary compression process for a hollow stepped shafts by the finite element method are given. The process for manufacturing hollow shafts was modeled using the Simufact.Forming simulation program. The FEM results are then verified experimentally in the designed forging machine for rotary compression. The experimental results confirm that axisymmetric hollow shafts can be produced by the rotary compression method. It is also confirmed that numerical methods are suitable for investigating both machine design and metal forming processes.

  13. Advanced numerical models for the thermo-mechanical-metallurgical analysis in hot forging processes

    Science.gov (United States)

    Ducato, Antonino; Fratini, Livan; Micari, Fabrizio

    2013-05-01

    In the paper a literature review of the numerical modeling of thermo-mechanical-metallurgical evolutions of a metal in hot forging operations is presented. In particular models of multiaxial loading tests are considered for carbon steels. The collected examples from literature regard phases transformations, also martensitic transformations, morphologies evolutions and transformation plasticity phenomena. The purpose of the tests is to show the correlation between the mechanical and the metallurgical behavior of a carbon steel during a combination of several types of loads. In particular a few mechanical tests with heat treatment are analyzed. Furthermore, Ti-6Al-4V titanium alloy is considered. Such material is a multi-phasic alloy, at room temperature made of two main different phases, namely Alpha and Beta, which evolve during both cooling and heating stages. Several numerical applications, conducted using a commercial implicit lagrangian FEM code are presented too. This code can conduct tri-coupled thermo-mechanical-metallurgical simulations of forming processes. The numerical model has been used to carry out a 3D simulation of a forging process of a complex shape part. The model is able to take into account the effects of all the phenomena resulting from the coupling of thermal, mechanical and metallurgical events. As simulation results strongly depend on the accuracy of input data, physical simulation experiments on real-material samples are carried out to characterize material behavior during phase transformation.

  14. FORGE Canada Consortium: outcomes of a 2-year national rare-disease gene-discovery project.

    Science.gov (United States)

    Beaulieu, Chandree L; Majewski, Jacek; Schwartzentruber, Jeremy; Samuels, Mark E; Fernandez, Bridget A; Bernier, Francois P; Brudno, Michael; Knoppers, Bartha; Marcadier, Janet; Dyment, David; Adam, Shelin; Bulman, Dennis E; Jones, Steve J M; Avard, Denise; Nguyen, Minh Thu; Rousseau, Francois; Marshall, Christian; Wintle, Richard F; Shen, Yaoqing; Scherer, Stephen W; Friedman, Jan M; Michaud, Jacques L; Boycott, Kym M

    2014-06-01

    Inherited monogenic disease has an enormous impact on the well-being of children and their families. Over half of the children living with one of these conditions are without a molecular diagnosis because of the rarity of the disease, the marked clinical heterogeneity, and the reality that there are thousands of rare diseases for which causative mutations have yet to be identified. It is in this context that in 2010 a Canadian consortium was formed to rapidly identify mutations causing a wide spectrum of pediatric-onset rare diseases by using whole-exome sequencing. The FORGE (Finding of Rare Disease Genes) Canada Consortium brought together clinicians and scientists from 21 genetics centers and three science and technology innovation centers from across Canada. From nation-wide requests for proposals, 264 disorders were selected for study from the 371 submitted; disease-causing variants (including in 67 genes not previously associated with human disease; 41 of these have been genetically or functionally validated, and 26 are currently under study) were identified for 146 disorders over a 2-year period. Here, we present our experience with four strategies employed for gene discovery and discuss FORGE's impact in a number of realms, from clinical diagnostics to the broadening of the phenotypic spectrum of many diseases to the biological insight gained into both disease states and normal human development. Lastly, on the basis of this experience, we discuss the way forward for rare-disease genetic discovery both in Canada and internationally.

  15. Nearshore sediment thickness, Fire Island, New York

    Science.gov (United States)

    Locker, Stanley D.; Miselis, Jennifer L.; Buster, Noreen A.; Hapke, Cheryl J.; Wadman, Heidi M.; McNinch, Jesse E.; Forde, Arnell S.; Stalk, Chelsea A.

    2017-04-03

    Investigations of coastal change at Fire Island, New York (N.Y.), sought to characterize sediment budgets and determine geologic framework controls on coastal processes. Nearshore sediment thickness is critical for assessing coastal system sediment availability, but it is largely unquantified due to the difficulty of conducting geological or geophysical surveys across the nearshore. This study used an amphibious vessel to acquire chirp subbottom profiles. These profiles were used to characterize nearshore geology and provide an assessment of nearshore sediment volume. Two resulting sediment-thickness maps are provided: total Holocene sediment thickness and the thickness of the active shoreface. The Holocene sediment section represents deposition above the maximum flooding surface that is related to the most recent marine transgression. The active shoreface section is the uppermost Holocene sediment, which is interpreted to represent the portion of the shoreface thought to contribute to present and future coastal behavior. The sediment distribution patterns correspond to previously defined zones of erosion, accretion, and stability along the island, demonstrating the importance of sediment availability in the coastal response to storms and seasonal variability. The eastern zone has a thin nearshore sediment thickness, except for an ebb-tidal deposit at the wilderness breach caused by Hurricane Sandy. Thicker sediment is found along a central zone that includes shoreface-attached sand ridges, which is consistent with a stable or accretional coastline in this area. The thickest overall Holocene section is found in the western zone of the study, where a thicker lower section of Holocene sediment appears related to the westward migration of Fire Island Inlet over several hundred years.

  16. Forging Ahead

    Science.gov (United States)

    Finkel, Ed

    2017-01-01

    Community colleges always have played an integral role in training workers for infrastructure- and transportation-related fields like truck driving, construction, welding and electrical work. If the $1 trillion infrastructure package proposed by President Donald Trump comes to pass, these fields will grow significantly, at least for a while, which…

  17. How thick is the lithosphere?

    Science.gov (United States)

    Kanamori, H; Press, F

    1970-04-25

    A rapid decrease in shear velocity in the suboceanic mantle is used to infer the thickness of the lithosphere. It is proposed that new and highly precise group velocity data constrain the solutions and imply a thickness near 70 km.

  18. Thick-Big Descriptions

    DEFF Research Database (Denmark)

    Lai, Signe Sophus

    The paper discusses the rewards and challenges of employing commercial audience measurements data – gathered by media industries for profitmaking purposes – in ethnographic research on the Internet in everyday life. It questions claims to the objectivity of big data (Anderson 2008), the assumption...... communication systems, language and behavior appear as texts, outputs, and discourses (data to be ‘found’) – big data then documents things that in earlier research required interviews and observations (data to be ‘made’) (Jensen 2014). However, web-measurement enterprises build audiences according...... to a commercial logic (boyd & Crawford 2011) and is as such directed by motives that call for specific types of sellable user data and specific segmentation strategies. In combining big data and ‘thick descriptions’ (Geertz 1973) scholars need to question how ethnographic fieldwork might map the ‘data not seen...

  19. Optimization of Forging Process of Intermediate Shaft%中间轴锻造工艺优化

    Institute of Scientific and Technical Information of China (English)

    胡晓琦; 李晓峰; 曹志远

    2013-01-01

    When producing the large asymmetrical flange etc hollow shaft parts with the conventional open die forging process, the flange side of hollow shaft part is very likely irregular offset and concave in center hole, which may affect the size of final forging and reduces the utilization rate of ingot. In this paper, a new forging process of intermediate shaft based on existing auxiliary tools is described and the confining of flange side center, end face deflection and offset irregularity of flange side were effectively improved and forging part with good size was obtained finally.%针对传统自由锻造工艺生产中间轴等非对称大法兰空心轴类件时,容易在法兰侧出现较为严重的偏摆和内孔凹心现象,影响最终锻件尺寸,坯料利用率低的缺点。介绍一种改进锻造工艺,在利用现有附具基础上,可有效克服中间轴锻件两端面内孔凹心、法兰长短面及其端面偏摆等技术难点,最终得到满足尺寸要求的锻件。

  20. Automated Determination of the Power Required and Selection of Electric Motors for Forging Fly-Press Mechanisms

    Directory of Open Access Journals (Sweden)

    K. Karakoulidis

    2015-06-01

    Full Text Available The current work deals with appropriate selection of electric motors for forging fly-press machines. To solve the equation of motion of the electric drive of these mechanisms characterized by impact (pulsating load and presence of flywheel, numerical methods (calculus have been used.

  1. Dynamic strain aging precipitation of Mg17Al12 in AZ80 magnesium alloy during multi-directional forging process

    Science.gov (United States)

    Zhu, Q. F.; Wang, G. S.; Wang, X. J.; Liu, F. Z.; Ban, C. Y.; Cui, J. Z.

    2017-05-01

    Dynamic aging precipitation of Mg17Al12 phases in AZ80 magnesium alloy was studied by multi-directional forging (MDF) with decreasing temperatures from 410 to 300 °C. The results show that the morphology of the dynamically precipitated β-Mg17Al12 phases (formed during forging process) exhibited granular shape. During the multi-directional forging process, the inhomogeneous dynamic precipitation of the β-Mg17Al12 phases result in the coexistence of the fine grains (with many granular Mg17Al12 phases) and coarse grains (without Mg17Al12 phases) in the samples. The fine grains (with many granular Mg17Al12 phases) area expands with the decreasing of final forging temperature. The inhomogenous Al content distribution in the Mg matrix leads to the non-uniform dynamic precipitation of the Mg17Al12 phase. These Mg17Al12 phase retards the growth of the DRX grains, which in turns results in the formation fine grains area during the during the MDF process with temperature decreasing.

  2. Forging New Cocoa Keys: The Impact of Unlocking the Cocoa Bean’s Genome on Pre-harvest Food Safety

    Science.gov (United States)

    Forging New Cocoa Keys: The Impact of Unlocking the Cocoa Bean’s Genome on Pre-harvest Food Safety David N. Kuhn, USDA ARS SHRS, Miami FL Sometimes it's hard to see the value and application of genomics to real world problems. How will sequencing the cacao genome affect West African farmers? Thi...

  3. Taking the Lead in Science Education: Forging Next-Generation Science Standards. International Science Benchmarking Report. Appendix

    Science.gov (United States)

    Achieve, Inc., 2010

    2010-01-01

    This appendix accompanies the report "Taking the Lead in Science Education: Forging Next-Generation Science Standards. International Science Benchmarking Report," a study conducted by Achieve to compare the science standards of 10 countries. This appendix includes the following: (1) PISA and TIMSS Assessment Rankings; (2) Courses and…

  4. Disentangling The Thick Concept Argument

    DEFF Research Database (Denmark)

    Blomberg, Olle

    2007-01-01

    Critics argue that non-cognitivism cannot adequately account for the existence and nature of some thick moral concepts. They use the existence of thick concepts as a lever in an argument against non-cognitivism, here called the Thick Concept Argument (TCA). While TCA is frequently invoked...

  5. Disentangling The Thick Concept Argument

    DEFF Research Database (Denmark)

    Blomberg, Olle

    2007-01-01

    Critics argue that non-cognitivism cannot adequately account for the existence and nature of some thick moral concepts. They use the existence of thick concepts as a lever in an argument against non-cognitivism, here called the Thick Concept Argument (TCA). While TCA is frequently invoked...

  6. Effects of Neutron Skin Thickness in Peripheral Nuclear Reactions

    Institute of Scientific and Technical Information of China (English)

    FANG De-Qing; MA Yu-Gang; CAI Xiang-Zhou; TIAN Wen-Dong; WANG Hong-Wei

    2011-01-01

    Effects of neutron skin thickness in peripheral nuclear collisions are investigated using the statistical abrasion ablation (SAA) model. The reaction cross section, neutron (proton) removal cross section, one-neutron (proton) removal cross section as well as their ratios for nuclei with different neutron skin thickness are studied. It is demonstrated that there are good linear correlations between these observables and the neutron skin thickness for neutron-rich nuclei. The ratio between the (one-)neutron and proton removal cross section is found to be the most sensitive observable of neutron skin thickness. Analysis shows that the relative increase of this ratio could be used to determine the neutron skin size in neutron-rich nuclei.%Effects of neutron skin thickness in peripheral nuclear collisions are investigated using the statistical abrasion ablation (SAA ) model.The reaction cross section,neutron (proton) removal cross section,one-neutron (proton) removal cross section as well as their ratios for nuclei with different neutron skin thickness are studied.It is demonstrated that there are good linear correlations between these observables and the neutron skin thickness for neutron-rich nuclei.The ratio between the (one-)neutron and proton removal cross section is found to be the most sensitive observable of neutron skin thickness.Analysis shows that the relative increase of this ratio could be used to determine the neutron skin size in neutron-rich nuclei.Determining the size and shape of a nucleus is one of the most important subjects since the discovery of atomic nuclei.The rms radii of the neutron (rn) and proton (rp) density distributions are among the most prominent observables for this purpose.Studies for stable nuclei have shown that the nuclear radii are proportional to A1/3,with A being the nuclear mass number.Meanwhile,the density distributions of neutrons and protons in stable nuclei are very similar.

  7. Forging Operation for Super-Large Main Shaft of Water Turbines%超大型轮机主轴锻造

    Institute of Scientific and Technical Information of China (English)

    胡晓琦; 张建国; 季雪; 牛广斌

    2014-01-01

    某大型轮机主轴法兰直径φ2.65 m,总长近10 m,锻件重达150 t,其规格超出水压机车间现有附具的工作范围,很难用传统锻造方法进行整体锻造生产。为此设计出一种新的锻造方法并对现有附具进行改造,最终成功锻造出形状和尺寸合格的大型轮机主轴锻件。%The main shaft of a large water turbine has a flange diameter ofφ2.65 m and is 10 m long. The weight of the main shaft forging is 150 t. Such large forging can not be made with the operational tools of the forging workshop and the monobloc forging is difficult to make with conventional forging operation. For this reason, a new forging process is designed and the operational tools are modified. With this effort, the large main shaft forging that has acceptable shape and dimensions is made successfully.

  8. Investigation of influencing factors on friction during ring test in hot forging using FEM simulation

    Science.gov (United States)

    Sethy, Ritanjali; Galdos, Lander; Mendiguren, Joseba; Sáenz de Argandoña, Eneko

    2016-10-01

    Few studies have been undertaken to understand the friction in hot forming, especially when addressing the issue of varying input parameters. Better understanding of their role is therefore needed in order to obtain accurate results in numerical simulations. This paper numerically investigates the high temperature ring compression test to evaluate how frictional behaviour is affected by variations of input parameters (i.e. press velocity, Heat Transfer Coefficient (HTC), processing time, mesh size, material and tool temperature). The high temperature ring-compression process was simulated by means of Finite Element Modelling (FEM) using FORGE-3D software with the ring made of AISI 304L having ratio of outer diameter, inner diameter and height of 30:15:10. According to the results, the HTC and the press velocity have most significant effects on frictional behavior and the calibration curves needed to calculate the friction coefficients after experimental testing.

  9. A Simplified Inverse Approach for the Simulation of Axi-Symmetrical Cold Forging Process

    Science.gov (United States)

    Halouani, A.; Li, Y. M.; Abbès, B.; Guo, Y. Q.

    2011-01-01

    This paper presents the formulation of an axi-symmetric element based on an efficient method called "Inverse Approach" (I.A.) for the numerical modeling of cold forging process. In contrast to the classical incremental methods, the Inverse Approach exploits the known shape of the final part and executes the calculation from the final part to the initial billet. The assumptions of the proportional loading and the simplified tool actions make the I.A. calculation very fast. The metal's incompressibility is ensured by the penalty method. The comparison with ABAQUS® and FORGE® shows the efficiency and limitations of the I.A. This simplified method will be a good tool for the preliminary preform design.

  10. Inner-product of strain rate vector through direction cosine in coordinates for disk forging

    Institute of Scientific and Technical Information of China (English)

    ZHAO De-wen; JIN Wen-zhong; WANG Lei; LIU Xiang-hua

    2006-01-01

    A new linear integration for plastic power was proposed. The effective strain rate for disk forging with bulge was expressed in terms of two-dimensional strain rate vector, and then its direction cosines were determined by the ratio of coordinate increments. Furthermore, inner-product of the vector for plastic power was term integrated by term and summed. Thereafter, through a formula for determination of bulge an analytical solution of stress effective factor was obtained. Finally, through compression tests, the calculated results of above formula were compared with those of Avitzur's approximate solution and total indicator readings of the testing machine. It is indicated that the calculated compression forces are basically in agreement with the measured ones if the pass reduction is less than 13.35%.However, when the reduction gets up to 25.34% and 33.12%, the corresponding errors between the calculated and measured results also get up to 6% and 13.5%, respectively.

  11. Grain size and texture changes of magnesium alloy AZ31 during multi-directional forging

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Grain size and texture changes of magnesium alloy AZ31 were studied in multidirectional forging(MDF) under decreasing temperature conditions. MDF was carried out up to large cumulative strains of 4.8 with changing the loading direction during decrease in temperature from pass to pass. MDF can accelerate the uniform development of fine-grained structures and increase the plastic workability at low temperatures. As a result, the MDFed alloy shows excellent higher strength as well as moderate ductility at room temperature even at the grain size below 1 μm. Superplastic flow takes place at 423 K and depends on the anisotropy of MDFed samples. The mechanisms of strain-induced free-grained structure development and of the plastic deformation were discussed in detail.

  12. Development of Iron-based Closed-Cell Foams by Powder Forging and Rolling

    Science.gov (United States)

    Paswan, Dayanand; Mistry, Dhananjay; Sahoo, K. L.; Srivastava, V. C.

    2013-08-01

    In the present investigation, an attempt has been made to develop in situ sandwich Fe-based foams using powder forging and rolling. Several metal carbonates are first studied by thermo gravimetric analysis to find out their suitability to be used as foaming agent for iron-based foams. Barium carbonate is found to be the most promising foaming agent among other suitable options studied such as SrCO3, CaCO3, MgCO3, etc. The effects of process parameters such as precursor composition, sintering temperature, foaming temperature and time, and content of foaming agent have been studied. The microstructural characteristics of the sintered precursor have been studied by means of optical and scanning electron microscopy. It was found that a good pore structure can be obtained using 2-3% C in Fe and 3% BaCO3 as foaming agent and by foaming at around 1350 °C for 3-6 min.

  13. Microstructural evolution of Mg-7Al-2Sn Mg alloy during multi-directional impact forging

    Directory of Open Access Journals (Sweden)

    M.G. Jiang

    2015-09-01

    Full Text Available Multi-directional impact forging (MDIF was applied to a Mg-7Al-2Sn (wt.% Mg alloy to investigate its effect on the microstructural evolution. MDIF process exhibited high grain refinement efficiency. After MDIF 200 passes, the grain size drastically decreased to 20 µm from the initial coarse grains of ~500 µm due to dynamic recrystallization (DRX. Meanwhile, original grain boundaries remained during MDIF and large numbers of fine spherical β-Mg17Al12 particles dynamically precipitated along the original grain boundaries with high Al concentration, acting as effective pinning obstacles for the suppression of DRXed grain growth. Besides, micro-cracks nucleated during MDIF and propagated along the interface between the remained globular or cubic Al-Mn particles and Mg matrix.

  14. New microalloyed steels for heavy duty forgings in cars and trucks

    Energy Technology Data Exchange (ETDEWEB)

    Arndt, J. [CDP Bharat Forge GmbH, Ennepetal (Germany)

    2005-07-01

    CDP Bharat Forge has carried out a substantial alloy and process development on microalloyed steels for controlled cooling. The main focus was put on the introduction of this development into series production of parts that were 100% heat treated before. The R+D-activities resulted in the new grades cdpSo38 and cdpSo40. For the grade cdpSo38 an impact energy of >25J (RT) and an elongation of >14% can be guaranteed for the series production of safety critical chassis parts at a yield strength of >600MPa. For the cdpSo40 a yield strength of >700MPa at 10% elongation can be guaranteed in series production. Two of the biggest truck manufacturers in the world have already changed their steering knuckles from heat treated steels 42CrMo4 and 30MnB5 to the new cdpBF-grades. (orig.)

  15. Friction and Adhesion in Dry Warm Forging of Magnesium Alloy with Coated Tools

    Science.gov (United States)

    Matsumoto, Ryo; Kawashima, Hiroaki; Osakada, Kozo

    In order to develop forging process of magnesium alloys without lubrication, frictional behavior of magnesium alloy AZ31B (Mg-3%Al-1%Zn) is evaluated by a tapered plug penetration test under dry condition. The cemented tungsten carbide (WC) plugs polished to be a mirror-like surface are coated with diamond-like carbon (DLC) and TiAlN by physical vapor deposition (PVD). The cylindrical hollow billets of AZ31B are penetrated by the tapered plugs at a temperature of 200°C. The surface roughness of the hole of the billet, the adhesion length of AZ31B on the plug surface and the penetration load are measured. Compared with WC and TiAlN coating, it is found that DLC coating is effective in preventing AZ31B from adhering to the tool surface and reducing the penetration load.

  16. Olivier Caïra, Jeux de rôle. Les forges de la fiction

    Directory of Open Access Journals (Sweden)

    Antoine Dauphragne

    2010-06-01

    Full Text Available Les forges de la fiction, d’Olivier Caïra, est à ranger parmi les rares ouvrages francophones en sciences humaines s’attachant au jeu de rôles. L’ouvrage en propose une analyse fine et dynamique centrée sur la pratique des joueurs. La démarche annoncée, qui entend proposer un texte accessible aussi bien aux rôlistes qu’aux universitaires, semble renvoyer autant à un souci de clarté qu’au profil de l’auteur. Olivier Caïra est sociologue ; ses travaux portent sur l’industrie du divertissement e...

  17. Development of Replacements for Phoscoating Used in Forging, Extrusion and Metal Forming Processes

    Energy Technology Data Exchange (ETDEWEB)

    Kerry Barnett

    2003-03-01

    Many forging, extrusion, heading and other metal forming processes use graphite-based lubricants, phosphate coatings, and other potentially hazardous or harmful substances to improve the tribology of the metal forming process. The application of phosphate-based coatings has long been studied to determine if other synthetic ''clean'' lubricants could provide the same degree of protection afforded by phoscoatings and its formulations. So far, none meets the cost and performance objectives provided by phoscoatings as a general aid to the metal forming industry. In as much as phoscoatings and graphite have replaced lead-based lubricants, the metal forming industry has had previous experience with a legislated requirement to change processes. However, without a proactive approach to phoscoating replacement, many metal forming processes could find themselves without a cost effective tribology material necessary for the metal forming process

  18. Essaying the mechanical hypothesis: Descartes, La Forge, and Malebranche on the formation of birthmarks.

    Science.gov (United States)

    Wilkin, Rebecca M

    2008-01-01

    This essay examines the determination by Cartesians to explain the maternal imagination's alleged role in the formation of birthmarks and the changing notion of monstrosity. Cartesians saw the formation of birthmarks as a challenge through which to demonstrate the heuristic capacity of mechanism. Descartes claimed to be able to explain the transmission of a perception from the mother's imagination to the fetus' skin without having recourse to the little pictures postulated by his contemporaries. La Forge offered a detailed account stating that the failure to explain the maternal imagination's impressions would cast doubt on mechanism. Whereas both characterized the birthmark as a deformation or monstrosity in miniature, Malebranche attributed a role to the maternal imagination in fashioning family likenesses. However, he also charged the mother's imagination with the transmission of original sin.

  19. Forging New, Non-traditional Partnerships Among Physicists, Teachers and Students

    Energy Technology Data Exchange (ETDEWEB)

    Bardeen, Marjorie [Fermilab; Adams, Mark [Illinois U., Chicago; Wayne, Mitchell [Notre Dame U.; Karmgard, Dan [Notre Dame U.; Goussiou, Anna [Washington U., Seattle

    2017-05-02

    The QuarkNet collaboration has forged new, nontraditional relationships among particle physicists, high school teachers and their students. QuarkNet provides professional development for teachers and creates opportunities for teachers and students to engage in particle physics data investigations and join research teams. Embedded in the U.S. particle research community, QuarkNet leverages the nature of particle physics research—the long duration of the experiments with extensive lead times, construction periods, and data collection and analysis periods. QuarkNet is patterned after the large collaborations with a central management infrastructure and a distributed workload across university- and lab-based research groups. We describe the important benefits of the QuarkNet outreach program that flow to university faculty and present successful strategies that others can adapt for use in their countries.

  20. Sinter-forged YBa sub 2 Cu sub 3 O sub 7-. delta

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Q.; Georgopoulos, P.; Johnson, D.L.; Marcy, H.O.; Kannewurf, C.R.; Hwu, S.J.; Marks, T.J.; Poeppelmeir, K.R.; Song, S.N.; Ketterson, J.B. (Northwestern Univ., Evanston, IL (USA))

    1987-07-01

    High T{sub c} ceramic superconductors, as exemplified by YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, have recently gained widespread interest in the scientific community. To date, the preparation of this and related materials in powder form has involved, with few exceptions, solid state reaction techniques. The resulting equilibrated powders, which are rather unsinterable, have typically been formed into pellets and fired for subsequent physical measurements. The densities of such pellets are considerably below the theoretical prediction, and the development of more effective sintering processes would clearly be of great importance. In this communication the authors report a technique (sinter-forging) whereby nearly theoretically dense (>95% TD) samples of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} can be produced. Physical measurements revealed strong texturing and preferred crystallite orientation as well as significant anisotropy in the charge transport.

  1. A Forging Hardness Dispersion Effect on the Energy Consumption of Machining

    Directory of Open Access Journals (Sweden)

    L. D. Mal'kova

    2015-01-01

    Full Text Available The aim of the work is to evaluate a hardness dispersion of forgings to be further machined, and analyse the impact of this dispersion on the resulting power consumption when cutting.The paper studies the hardness values of three kinds of parts for automotive manufacturing. Sample of each part was n = 100 pieces. Analysis of measurements showed that 46% - 93% of parts meet requirements for a range defined by the work-piece working drawing. It was found that hardness of one batch of forgings is under dispersion, which distribution is governed by the normal law.The work provides calculations for machining the external cylindrical surfaces of the considered parts. In the context of calculating are adopted parameters of the enterprise-processing rate. It is found that power consumption of machining because of the dispersion values of the work-piece hardness is a function of the random BH variable and it itself is a random variable. Two types of samples are considered, namely: the full sample and that of the values that meet requirements for hardness. The coefficient of variation for samples that meet the technical requirements for hardness is lower than for the full samples, so their average value is more reliable characteristic of a set. It was also found that to ensure a reliable prediction of power consumption in designing the manufacturing processes it is necessary to reduce a tolerance range of workpiece hardness to the limit.The work gives a comparative evaluation of electric power consumption per unit cylindrical surface of the parts under consideration. A relative change in the electric power consumed at the minimum and maximum levels of the hardness value was introduced as an evaluation criterion. It is found that with changing hardness of machined work-pieces within the tolerance, the change in power consumption in machining the unit surface reaches 16% while in the case its being out of the specified range it does 47%.

  2. Research of upsetting ratio in forming processes on a three – slides forging press

    Directory of Open Access Journals (Sweden)

    W.S. Weroński

    2006-04-01

    Full Text Available Purpose: The purpose of the presented in this work research was determining the limiting conditions of upsetting in three-slide forging press (TSFP. The free upsetting process and upsetting process in cylindrical impression were analyzed.Design/methodology/approach: The assumed purpose was confirmed in experimental research. For the case of upsetting in cylindrical impression, the research of limiting upsetting coefficients were made for different diameters and impression lengths. Findings: The obtained results showed large variety of limiting upsetting ratio depending on the analyzed impression geometrical parameters. It was stated, that there are 3 phenomena limiting the upsetting process in the die. The main phenomenon is the bar upsetting outside the impression. The upsetting processes in the impression are limited also by bar buckling outside the impression and overlapping inside the impressionResearch limitations/implications: The results of research allowed for stating that, besides the process geometrical parameters, friction conditions and type of the formed material influenced the limiting upsetting coefficients in the cylindrical impression. It is purposeful to make the further research determining quantitative and qualitative dependencies between these factors. Practical implications: The obtained results are the basis for designing of forming processes in TSFP in which the upsetting dominates. Especially it considers the elongated forgings and elongated preforms with thickeningsOriginality/value: The influence of the impression geometrical parameters on the limiting upsetting coefficients for the case of upsetting in cylindrical impression in TSFP has been analyzed in details. The dependencies, which should be used during designing of upsetting processes in TSFP were determined.

  3. 自由锻造液压机的技术现状及设计分析%Technique status and design analysis of free forging hydraulic press

    Institute of Scientific and Technical Information of China (English)

    谢广玉; 李秀珠; 胡海燕

    2013-01-01

    阐述了自由锻造液压机的发展过程和我国锻造压机的技术现状,对自由锻造液压机的几种结构型式和传动方式进行了比较,说明了锻造油压机的技术特点.%The developing process of free forging hydraulic press and technique status in China has been described in the text. Several structural modes and transmission modes of free forging hydraulic press have been compared, and the technical characteristics of forging hydraulic press have been introduced.

  4. Medida da espessura do segmento uterino inferior em gestantes com cesárea prévia: análise da reprodutibilidade intra- e interobservador por ultra-sonografia bi- e tridimensional Lower uterine segment thickness measurement in pregnant women with previous caesarean section: intra- and interobserver reliability analysis using bi- and tridimensional ultrasonography

    Directory of Open Access Journals (Sweden)

    Daniela de Abreu Barra

    2008-03-01

    interferir na conduta do obstetra ou antecipar o parto, foi feito por medidas bidimensionais abdominais da espessura total.PURPOSE: to compare the intra and interobserver reproducibility of the total thickness measurement of the inferior uterine segment (IUS, through the abdominal route, and of the muscle layer measurement, through the vaginal route, using bi and tridimensional ultrasonography. METHODS: the IUS thickness measurement of 30 women, between the 36th and 39th weeks of gestation with previous caesarean section, done by two observers, was studied. Abdominal ultrasonography with the patient in both supine and lithotomy position was performed. In the sagittal section, the IUS was identified and four bidimensional images and two tridimensional blocks of the total thickness were collected through the abdominal route, and the same for the muscle layer, through the vaginal route. Tridimensional acquisitions were manipulated in the multiplanar mode. The time was measured with a chronometer. Reproducibility was evaluated by the computation of the absolute difference between measurements, the ratio of differences smaller than 1 mm, the intraclass coefficient (ICC, and the Bland and Altman's concordance limits. RESULTS: the average bidimensional measurement of IUS thickness was 7.4 mm through the abdominal and 2.7 mm through the vaginal route, and the tridimensional measurement was 6.9 mm through the abdominal and 5.1 mm through the vaginal route. Intra- and interobserver reproducibility of vaginal versus abdominal route: smaller absolute difference (0.2-0.4 mm versus 0.8-1.5 mm, greater ratio of differences (85.8-97.8% versus 48.7-72,8%, with p0.05[A1] and similar lower concordance limits (-38 to 3.4 versus -3.6 to 4 mm for tridimensional ultrasonography and ICC (0.6-0.9 versus 0.7-0.9. CONCLUSIONS: from the above, we came to the conclusion that the measurement of the IUS muscle layer, through the vaginal route using tridimensional ultrasonography is more reproducible

  5. 卡贝缩宫素对妊娠疤痕子宫剖宫产术中出血量及子宫肌层厚度的影响%Effect of carbetocin on blood loss and uterine muscular layer thickness during cesarean section

    Institute of Scientific and Technical Information of China (English)

    彭艳; 李晓红; 张靖域; 丁桂凤

    2016-01-01

    Objective To explore the effect of carbetocin on operative blood loss and uterine muscular layer thickness during cesarean section, and provide theoretical basis for clinical work. Methods A total of 282 cases of preg-nant women, who admitted to Department of Gynecology and Obstetrics in our hospital from January 2012 to June 2014, were selected and randomly divided into the observation group and the control group according to the random number ta-ble, with 141 patients in each group. In cesarean section, the observation group received one-time injection of carbetocin, and the control group underwent one-time injection of oxytocin. The operation time, hospitalization time, uterine contrac-tion effect, blood loss after operation, uterine muscular layer thickness, postoperative life indications and complications of the two groups were compared. Results The operation time of the observation group (94.4 ± 11.4) min was signifi-cantly shorter than that of the control group (121.2 ± 8.3) min, P0.05). Conclusion Carbetocin can significantly reduce blood volume, improve the quality of life of pregnant women in long term, and improve the effective thickness of anterior and posterior uterine wall and pelvic floor muscular layer, which is safe and effective, and worthy of clinical application.%目的:探讨卡贝缩宫素对妊娠疤痕子宫行剖宫产手术的出血量及子宫肌层厚度的影响,以期为临床工作提供理论依据。方法将2012年1月至2014年6月于我院妇产科接受剖宫产分娩的282例孕妇纳入研究,将孕妇按照随机数表法随机分为观察组和对照组,每组141例。观察组孕妇于宫体处接受一次性注射卡贝缩宫素,对照组孕妇接受一次性注射缩宫素,比较两组孕妇的手术时间、住院时间、宫缩效果、术后出血量、子宫肌层厚度、术后生命指征以及并发症发生情况。结果观察组产妇的手术时间为(94.4±11.4) min,与对照组的(121.2±8

  6. Optimal Design of Fuel Injector Bodies Forging Die%喷油器体锻模优化设计

    Institute of Scientific and Technical Information of China (English)

    李志广; 刘碧芬; 宋伟民

    2014-01-01

    Objective This study used the fuel injector bodies die forging forming as the research object,analyzed and optimized the design of the forging die structure and size. Methods The original disadvantages of forging die design were a-voided by optimal design of forging die (especially the design optimization of the structure and size of lock, finishing im-pression, flash cave, gate and edge rolling impression, and optimization of the raw materials blanking specification accord-ing to the height of the edge rolling impression). Results The fuel injector body die forging forming process was improved, the metal difficult deformation area and deformation force were reduced, the consumption was reduced by 0. 15 kg/ piece, the rate of qualified products and the forging efficiency (the hammer speed was reduced by 3 ~ 5 times/ piece) were in-creased, the service life of die forging was at least doubled and the cost was reduced. Conclusion The fuel injector bodies forging die finally obtained had compact structure, enough strength and superior performance, which provide powerful refer-ence for the design and actual production of similar forging dies.%目的:以喷油器体模锻成形为研究对象,对锻模结构与尺寸进行分析和优化设计。方法通过优化锻模设计(尤其是优化锁扣、终锻模膛、飞边槽、钳口、滚挤模膛等结构与尺寸设计以及根据滚挤模膛高度尺寸优选原材料下料规格),克服原锻模设计的缺点。结果有效改善了喷油器体的模锻工艺性,减小了难变形区,减小了变形力,减少了原材料消耗0.15 kg /件,提高了合格品率,提高了锻造效率(减少打击次数3~5锤次/件),提高了锻模使用寿命至少1倍,以及降低了锻模与锻件成本等。结论最终获得的喷油器体锻模,结构高紧凑又强度足够,使用性能优越,可为类似锻模设计和实际生产提供了有力的参考依据。

  7. Optimum thickness of Mossbauer absorber

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    If recoilless fraction fa is available, the optimum absorber thickness dopt can be calculated by maximizing the signal to noise ratio or Q factor. In this work,an approach presented is to get experimental Qexp as a function of the thickness, and then fitting Qexp by its theoretical expression gives fa value. At last the dopt value is deduced from a maximum on the fitted curve. In such a way, thicknesses of six specimens with quadrupole or magnetic hyperfine splitting were optimized.

  8. Static and dynamic through thickness lamina properties of thick laminates

    NARCIS (Netherlands)

    Lahuerta, F.; Nijssen, R.P.L.; Van der Meer, F.P.; Sluys, L.J.

    2015-01-01

    Thick laminates are increasingly present in large composites structures such as wind turbine blades. Different factors are suspected to be involved in the decreased static and dynamic performance of thick laminates. These include the effect of self-heating, the scaling effect, and the manufacturing

  9. Surface fatigue and failure characteristics of hot forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    Science.gov (United States)

    Townsend, D. P.

    1986-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground SISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  10. Surface fatigue and failure characteristics of hot-forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    Science.gov (United States)

    Townsend, Dennis P.

    1987-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground AISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  11. Three-dimensional Numerical Simulation and Experimental Analysis of Austenite Grain Growth Behavior in Hot Forging Processes of 300M Steel Large Components

    Institute of Scientific and Technical Information of China (English)

    Jiao LUO; Ying-gang LIU; Miao-quan LI

    2016-01-01

    The microstructure models were integrated into finite element (FE)code,and a three-dimensional (3D) FE analysis on the entire hot forging processes of 300M steel large components was performed to predict the distri-butions of effective strain,temperature field and austenite grain size.The simulated results show that the finest grains distribute in the maximum effective strain region because large strain induces the occurrence of dynamic re-crystallization.However,coarse macro-grains appear in the minimum effective strain region.Then,300M steel forg-ing test was performed to validate the results of FE simulation,and microstructure observations and quantitative analysis were implemented.The average relative difference between the calculated and experimental austenite grain size is 7.5 6%,implying that the present microstructure models are reasonable and can be used to analyze the hot forging processes of 300M steel.

  12. A apropriação de imagens de arquivo na obra de Harun Farocki e Péter Forgács

    National Research Council Canada - National Science Library

    Jamer Guterres de Mello

    2012-01-01

    .... For this purpose, someaspects of the filmography of Harun Farocki and Péter Forgács will be analyzed. These twoartists have been adopting this gesture of appropriation, causing the re-signification of theoriginal meanings...

  13. Changes of epidermal thickness in vitiligo.

    Science.gov (United States)

    Jung, Soo-Eun; Kang, Hee Young; Lee, Eun-So; Kim, You Chan

    2015-04-01

    The stratum corneum and epidermal pigmentation have protective roles against ultraviolet radiation. Because vitiligo skin lacks melanocytes and has no potential to produce pigment, some studies suggested that the epidermis in vitiligo skin is thicker than in normal skin. However, only a few studies investigated epidermal thickness changes in vitiligo, and some of these had relatively small sample sizes. Thus, this study aimed to compare epidermal thickness between vitiligo skin and adjacent normal-appearing skin in a large cohort. Photos of hematoxylin and eosin–stained slides of vitiligo skin and adjacent normal-appearing skin were taken under a microscope. The thicknesses of the stratum corneum, viable epidermis, and full epidermis were then measured by a computerized image analyzer. A total of 206 patients (412 sections) were included. There were significant differences between vitiligo skin and adjacent normal-appearing skin in the thickness of the stratum corneum (P = 0.009), viable epidermis (P = 0.001), and total epidermis (P = 0.001). An analysis comparing skin biopsied from a sun-exposed area versus a sun-protected area showed that the stratum corneum, viable epidermis, and total epidermis were significantly thicker in vitiligo skin than in normal-appearing skin in sun-exposed areas (P vitiligo skin than in normal-appearing skin, especially on sun-exposed skin, and that this may represent a photoprotective role compensating for absent pigmentation.

  14. HPPMS (Cr1-xAlx)N WSy Coatings for the Application in Dry Cold Forging of Steel: Sythesis and Raman Characterization

    OpenAIRE

    Bobzin, Kirsten

    2016-01-01

    Lubricants are applied to reduce friction between workpieces and forming tools in cold forging processes. There is a strong demand to avoid lubricants due to economic, ecological and legislative aspects. PVD coatings took over the tasks of lubricants in numerous applications in the recent years. They may enormously reduce tool and workpiece wear in cold forging or deliver special functions even in the absence of lubricants. However, the abdication of lubricants goes along with the requirement...

  15. Forging Performance Comparison of New Composite Surface-anvil%新型复合曲面型砧的锻造性能比较

    Institute of Scientific and Technical Information of China (English)

    李静; 孟祥龙; 陈荣强; 于晶晶

    2011-01-01

    Taking the large-scale steel ingot forging process as study object, through theory modeling and numerical imulation, the uniformity of the heavy forging distortion was researched; through comparing the forging effect between V swage block and compound surface swage block, the forging's internal stress and strain condition was discussed. The results show that the compound surface swage block in the forging structure and property optimization has superiority, which can enable the large-scale forging core to obtain very well compactive effort, effectively eliminate the segregation, shrink and porosity flaw that appears in the steel ingot interior, also can make the large-scale forging surface's metal flow under very good control, and eliminate the difficult deformation range in the forging process.%以大型钢锭锻造过程为研究对象,通过理论建模和数值模拟,对大锻件变形的均匀性进行研究,将新型复合曲面型砧和传统V型砧的锻造结果进行比较,以求技出在用不同砧子进行锻造时,锻件内部的应力、应变状态.结果表明,复合曲面型砧在锻件组织性能优化上具有优势,其不但能使大型锻件心部得到很好的压实效果,有效地消除了钢锭内部出现的偏析、疏松及缩孔缺陷,而且大型锻件表面金属变形也能得到很好的控制,消除了锻造过程中的难变形区.

  16. Choroidal Thickness Measured by Spectral Domain Optical Coherence Tomography: Factors Affecting Thickness in Glaucoma Patients

    Science.gov (United States)

    Maul, Eugenio A.; Friedman, David S.; Chang, Dolly S.; Boland, Michael V.; Ramulu, Pradeep Y.; Jampel, Henry D.; Quigley, Harry A.

    2011-01-01

    Purpose To measure choroidal thickness and to determine parameters associated with it. Design Cross-sectional study. Participants Seventy-four glaucoma patients and glaucoma suspects. Methods Spectral domain optical coherence tomography (SDOCT) scans were obtained to estimate average choroidal thickness in a group of glaucoma suspects and glaucoma patients. Average thickness was calculated from enhanced depth SDOCT images and manually analyzed with Image J software. Open angle glaucoma, open angle glaucoma suspect, primary angle closure glaucoma, primary angle closure, and primary angle closure suspect were defined by published criteria. Glaucoma suspects had normal visual fields bilaterally. Glaucoma was defined by specific criteria for optic disc damage and visual field loss in at least one eye. The most affected eye was analyzed for comparisons across individuals, while right/left and upper half/lower half comparisons were made to compare thickness against degree of visual field damage. Main Outcome Measured Average macular and peripapillary choroidal thickness measured using SDOCT. Results The choroidal-scleral interface (CSI) was visualized in 86% and 96% of the macular and peripapillary scans, respectively. In multivariable linear regression analysis, the macular choroid was significantly thinner in association with 4 features: longer eyes (22 µm per mm longer [95% confidence Interval (CI): −33, −11]), older individuals (31 µm thinner per decade older [95% CI: −44 −17]), lower diastolic ocular perfusion pressure (26 µm thinner per 10 mmHg lower [95% CI: 8, 44]), and thicker central corneas (6 µm per 10 µm thicker cornea [95% CI: −10, 0]). The choroid was not significantly thinner in glaucoma patients than in suspects (14 µm [95% CI: −54, 26], p=0.5). Peripapillary choroidal thickness was not significantly different between glaucomaand suspect patients. Thickness was not associated with damage severity as estimated by visual field mean

  17. High-frequency ultrasonic imaging of thickly sliced specimens

    Science.gov (United States)

    Miyasaka, Chiaki; Tittmann, Bernhard R.; Chandraratna, Premindra A. N.

    2003-07-01

    It has been reported that a mechanical scanning reflection acoustic microscope (hereinafter called simply "SAM"), using high frequency ultrasonic tone-burst waves, can form a horizontal cross-sectional image (i.e., c-scan image) showing a highly resolved cellular structure of biological tissue. However, the tissue prepared for the SAM has been mostly a thinly sectioned specimen. In this study, the SAM images of specimens thickly sectioned from the tissue were analyzed. Optical and scanning acoustic microscopies were used to evaluate tissues of human small intestine and esophagus. For preparing thin specimens, the tissue was embedded in paraffin, and substantially sectioned at 5-10μm by the microtome. For optical microscopy, the tissue was stained with hematoxylin and eosin, and affixed onto glass substrates. For scanning acoustic microscopy, two types of specimens were prepared: thinly sectioned specimens affixed on the glass substrate, wherein the specimens were deparaffinized in xylene, but not stained, and thickely sectioned specimens. Images of the thick specimens obtained with frequency at 200 MHz revealed cellular structures. The morphology was very similar to that seen in the thinly sectioned specimens with optical and scanning acoustic microscopy. In addition, scanning electron microscopy was used to compare the images of biological tissue. An acoustic lens with frequency at 200 MHz permitted the imaging of surface and/or subsurface of microstructures in the thick sections of small intestine and esophagus.

  18. Defining a method of evaluating die life performance by using finite element models (FEM) and a practical open die hot forging method

    Science.gov (United States)

    Marashi, J.; Foster, J.; Zante, R.

    2016-10-01

    Die wear, which is defined as a surface damage or removal of material from one or both of two solid surfaces in a sliding, rolling or impact motion relative to one another, is considered the main cause of tool failure. Wear is responsible for 70% of tool failure and a potential source of high costs; as much as 30% per forging unit in the forging industries [1]. This paper presents a unique wear prediction and measurement method for open die forging using a modified Archard equation, 3D FE simulation (to represent the actual forging process precisely) and an industrial scale forging trial. The proposed tool and experimental design is aimed at facilitating a cost effective method of tool wear analysis and to establish a repeatable method of measurement. It creates a platform to test different type of lubricants and coatings on industrial scale environment. The forging trial was carried out using 2100T Schuler Screw press. A full factorial experiment design was used on 3D simulation to identify the process setting for creating a measurable amount of tool wear. Wear prediction of 28.5 µm based on the simulation correlated with both Infinite Focus Optical Microscope and Coordinate Measuring Machine (CMM) measurement results of the practical trial. Thermal camera reading showed temperature raise on the area with maximum wear, which suggests that increase in contact time, causes thermal softening on tool steel. The measurement showed that abrasive wear and adhesive wear are dominant failure modes on the tool under these process conditions.

  19. 轴承锻件整径工装改进%Improvement of repair diameter tooling for bearing forging

    Institute of Scientific and Technical Information of China (English)

    单晓伟; 常玉滨

    2016-01-01

    The repair diameter process for bearing forging outer ring and inner ring generally performed on different machines. For saving machines, one maching was used to repair diameter of bearing forging inner ring and outer ring, but wasting time and strength when replacement products. In view of the existing problems, the repair diameter tooling was improved to enhance production efifciency and machine utilization.%轴承锻件外圈和内圈整径工序一般在不同机床上进行。为节省机床,准备用一台机床对内、外圈整径,但换活时费时费力。针对存在的问题,改进了整径工装,提高了生产效率和机床利用率。

  20. Influence of Hot forging on Tribological behavior of Al6061-TiB2 In-situ composites

    Science.gov (United States)

    Pradeep kumar, G. S.; Keshavamurthy, R.; kuppahalli, Prabhakar; kumari, Prachi

    2016-09-01

    Al6061-TiB2 metal matrix composite was fabricated by stir casting technique via in-situ reaction, using mixture of Al6061 alloy, Potassium tetraflouroborate salt (KBF4) and tetraflourotitanate (K2TiF6). The cast composites were processed to hot forging, SEM studies; X- ray Diffraction studies (XRD), Microhardness and Dry friction and wear tests. Pin on disc type machine was used to perform tribological tests over a load range of 20-100N and sliding velocities of 0.314-1.57m/s. SEM and XRD studies confirms formation of fine in-situ TiB2 particles. Composites exhibit higher Microhardness, improved wear resistance and Lower COF with formation of TiB2 particles when compared with the unreinforced alloy. Compared to cast alloy and its Composites, forged alloy and its composites show superior Tribological behavior under similar test conditions.

  1. Studies of the quality and cost-effectiveness of a novel conceptof open-die forged powerplant main shaft

    Directory of Open Access Journals (Sweden)

    P. Skubisz

    2015-04-01

    Full Text Available An innovatory concept of open-die forging of windmill main shaft is described. Comparative study of the new technology based on the concept of cogging hollow shaft on mandrel featuring material savings and higher quality of a finished part versus traditional production chain of this component is presented, indicating benefits and technological setbacks of industrial implementation. Results of industrial sampling aided with numerical simulation form guidelines for technological realization.

  2. Simulations and Experiments of Hot Forging Design and Evaluation of the Aircraft Landing Gear Barrel Al Alloy Structure

    Science.gov (United States)

    Ram Prabhu, T.

    2016-04-01

    In the present study, the hot forging design of a typical landing gear barrel was evolved using finite element simulations and validated with experiments. A DEFORM3D software was used to evolve the forging steps to obtain the sound quality part free of defects with minimum press force requirements. The hot forging trial of a barrel structure was carried out in a 30 MN hydraulic press based on the simulation outputs. The tensile properties of the part were evaluated by taking samples from all three orientations (longitudinal, long transverse, short transverse). The hardness and microstructure of the part were also investigated. To study the soundness of the product, fluorescent penetrant inspection and ultrasonic testing were performed in order to identify any potential surface or internal defects in the part. From experiments, it was found that the part was formed successfully without any forging defects such as under filling, laps, or folds that validated the effectiveness of the process simulation. The tensile properties of the part were well above the specification limit (>10%) and the properties variation with respect to the orientation was less than 2.5%. The part has qualified the surface defects level of Mil Std 1907 Grade C and the internal defects level of AMS 2630 Class A (2 mm FBh). The microstructure shows mean grain length and width of 167 and 66 µm in the longitudinal direction. However, microstructure results revealed that the coarse grain structure was observed on the flat surface near the lug region due to the dead zone formation. An innovative and simple method of milling the surface layer after each pressing operation was applied to solve the problem of the surface coarse grain structure.

  3. Effect of molybdenum addition on the mechanical properties of sinter-forged Fe–Cu–C alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rathore, Sanjay S., E-mail: rathore.sanjaysingh@gmail.com; Salve, Milind M., E-mail: milindrowling@gmail.com; Dabhade, Vikram V., E-mail: vvdabfmt@iitr.ac.in

    2015-11-15

    Molybdenum provides solid solution strengthening, enhances hardenability and has thus been used to improve mechanical properties of ferrous alloys significantly. The present study reports the effect of molybdenum addition on the properties of sinter-forged Fe–Cu–C alloys prepared using elemental powders under various heat treatment conditions. The elemental powder mixtures were compacted at a pressure of 500 MPa followed by sintering at 1120 °C in N{sub 2}–20%H{sub 2} atmosphere. Further, the sintered compacts were immediately forged at the sintering temperature in a closed die. The sinter-forged compacts were further homogenized and then heat treated under different cooling rates. Enhancement of the mechanical properties (hardness and tensile strength) were observed with Mo addition and increase in severity of quench. Hardness of air cooled samples was slightly lower than that of the water quenched samples but comparable with oil quenched samples. However, no significant increase in hardness was observed beyond 1.5 wt% Mo addition for all cooling conditions. At higher molybdenum content ductility was retained due to stabilization of ferrite phase by molybdenum. The microstructural study showed mostly ferrite–pearlite structure in furnace cooled condition whereas a complex microstructure was observed in the faster cooling conditions. Grain refinement was also observed with molybdenum addition. - Highlights: • Mo (0.25–4.0 wt%) addition in sinter-forged Fe–2Cu–0.65C alloys was investigated. • Effect of heat treatment on mechanical properties and microstructure was discussed. • Hardness and strength increased with Mo addition at the expense of ductility. • Hardness in air cooled condition was comparable with oil/water cooled conditions.

  4. Contribution to the history of technology and weaponry: experimental forging of arrowheads using ancient iron bars

    Directory of Open Access Journals (Sweden)

    Renoux, Guillaume

    2009-12-01

    Full Text Available This study is devoted to experiments for defining the forging conditions of roman iron ingots (bars; its purpose is to obtain various arrow heads similar to those issued from the famous site of Uxellodunum (Le Puy d’Issolud, Lot, the last fight of Caesar in Gaul. The main part of work is realized with currency bars found in loads of roman shipwrecks, in Mediterranean Sea, near Les Saintes-Maries-de-la-Mer; two smaller bars are issued from the Pyrenean site of Le Couperé, near Saint-Bertrand-de-Comminges. Effects of the various parameters of forging conditions on metal are analyzed by optical microscopy; they let to reach the different typologies and microstructural features observed with antique arrow heads.

    Cette étude porte sur la recherche des conditions de forgeage optimales ayant conduit à la réalisation de pointes de flèche diverses, identiques à celles dont on dispose pour l’époque antique, parfois en grande abondance, comme cela est le cas pour le site du siège d’Uxellodunum, au Puy d’Issolud (Lot. L’expérimentation a été conduite avec le concours d’un taillandier spécialiste de la restitution d’armes anciennes. L’originalité du travail porte sur le choix du forgeage de barres archéologiques issues des épaves gisant au large des Saintes-Maries-de-la-Mer, en Méditerranée, et des fouilles du Couperé à Saint Bertrand de Comminges, dans les Pyrénées. La caractérisation métallographique préalable de ces barres nous a permis de suivre l’incidence des conditions de forgeage sur la microstructure des pointes de flèche réalisées. Les principaux faciès typologiques et microstructuraux des flèches antiques ont été reproduits, permettant ainsi d’affiner la connaissance technique du protocole de forgeage du fer, au début de notre ère.

  5. Technology of Truss Anchor Composite Support in Thick Coal Seam Super Large-Section Open-off Cut%桁架锚索复合支护技术在特大断面厚煤层切巷的应用

    Institute of Scientific and Technical Information of China (English)

    高星照

    2015-01-01

    This paper as the research object of the surrounding rock control of the open-off cut at the mine in Shanxi, it analyzed the control mechanism of truss anchor composite combined technology by classiifed surrounding rock stability of 412 open-off cut in a mine, and truss anchor composite combined technology key parameters were determined by FLAC3D numerical analysis, truss anchor combined technology was proposed in thick coal super large-section open-off cut. Engineering practice indicated that the open-off cut could realize self-stabled 24days after caving open-off cut, and the sidewall convergence was 93mm, and the maximum displacement of lfoor rock was 143mm, and the total roof separation was 9mm. So the combined truss and bolt technology had performed well in controlling the deformation of surrounding rock.%该文以山西某矿412特大断面切巷围岩控制为研究对象,分析了预应力桁架锚索控制机理,并运用FLAC3D模拟确定桁架锚索复合支护的关键参数,提出了特大断面厚煤层切巷的桁架锚索复合支护技术;实践表明,切巷自掘出后22d实现自稳,两帮移近量最大为90mm,顶板下沉量最大为142mm,顶板离层仅为8mm,围岩变形控制良好。

  6. The Influence of Temperature on the Frictional Behavior of Duplex-Coated Die Steel Rubbing Against Forging Brass

    Science.gov (United States)

    Ebrahimzadeh, I.; Ashrafizadeh, F.

    2015-01-01

    Improvement of die life under hot forging of brass alloys is considered vital from both economical and technical points of view. One of the best methods for improving die life is duplex coatings. In this research, the influence of temperature on the tribological behavior of duplex-coated die steel rubbing against forging brass was investigated. The wear tests were performed on a pin-on-disk machine from room temperature to 700 °C; the pins were made in H13 hot work tool steel treated by plasma nitriding and by PVD coatings of TiN-TiAlN-CrAlN. The disks were machined from a two-phase brass alloy too. The results revealed that the friction coefficient of this tribosystem went through a maximum at 550 °C and decreased largely at 700 °C. Furthermore, the formation of Cr2O3 caused the reduction of friction coefficient at 700 °C. PVD coatings proved their wear resistance up to 550 °C, well above the working temperature of the brass forging dies.

  7. Effect of solution treatment on the fatigue behavior of an as-forged Mg-Zn-Y-Zr alloy

    Science.gov (United States)

    Wang, S. D.; Xu, D. K.; Wang, B. J.; Han, E. H.; Dong, C.

    2016-04-01

    Through investigating and comparing the fatigue behavior of an as-forged Mg-6.7Zn-1.3Y-0.6Zr (wt.%) alloy before and after solid solution treatment (T4) in laboratory air, the effect of T4 treatment on fatigue crack initiation was disclosed. S-N curves illustrated that the fatigue strength of as-forged samples was 110 MPa, whereas the fatigue strength of T4 samples was only 80 MPa. Observations to fracture surfaces demonstrated that for as-forged samples, fatigue crack initiation sites were covered with a layer of oxide film. However, due to the coarse grain structure and the dissolution of MgZn2 precipitates, the activation and accumulation of {10–12} twins in T4 samples were much easier, resulting in the preferential fatigue crack initiation at cracked twin boundaries (TBs). Surface characterization demonstrated that TB cracking was mainly ascribed to the incompatible plastic deformation in the twinned area and nearby α-Mg matrix.

  8. An Assessment of the Ductile Fracture Behavior of Hot Isostatically Pressed and Forged 304L Stainless Steel

    Science.gov (United States)

    Cooper, A. J.; Smith, R. J.; Sherry, A. H.

    2017-02-01

    Type 300 austenitic stainless steel manufactured by hot isostatic pressing (HIP) has recently been shown to exhibit subtly different fracture behavior from that of equivalent graded forged steel, whereby the oxygen remaining in the component after HIP manifests itself in the austenite matrix as nonmetallic oxide inclusions. These inclusions facilitate fracture by acting as nucleation sites for the initiation, growth, and coalescence of microvoids in the plastically deforming austenite matrix. Here, we perform analyses based on the Rice-Tracey (RT) void growth model, supported by instrumented Charpy and J-integral fracture toughness testing at ambient temperature, to characterize the degree of void growth ahead of both a V-notch and crack in 304L stainless steel. We show that the hot isostatically pressed (HIP'd) 304L steel exhibits a lower critical void growth at the onset of fracture than that observed in forged 304L steel, which ultimately results in HIP'd steel exhibiting lower fracture toughness at initiation and impact toughness. Although the reduction in toughness of HIP'd steel is not detrimental to its use, due to the steel's sufficiently high toughness, the study does indicate that HIP'd and forged 304L steel behave as subtly different materials at a microstructural level with respect to their fracture behavior.

  9. Effect of Nano-Scale and Micro-Scale Yttria Reinforcement on Powder Forged AA-7075 Composites

    Science.gov (United States)

    Joshi, Tilak C.; Prakash, U.; Dabhade, Vikram V.

    2016-05-01

    The present investigation deals with the development of AA-7075 metal matrix composites reinforced with nano yttria particles (0.1 to 3 vol.%) and micron yttria particles (1 to 15 vol.%) by powder forging. Matrix powders (AA-7075) and reinforcement powders (yttria) were blended, cold compacted, sintered under pure nitrogen, and finally hot forged in a closed floating die. The hot forged samples were artificially age hardened at 121 °C for various time durations to determine the peak aging time. The mechanical properties in the peak-aged condition as well as density and microstructure were determined and correlated with the reinforcement size and content. The nano composites exhibited a well-densified structure as well as better hardness and tensile/compressive strength as compared to micro-scale composites. The mechanical properties in nano-scale composites peaked at 0.5 vol.% yttria addition while for micro-scale composites these properties peaked at 5 vol.% yttria addition.

  10. Experimental Investigation and Numerical Simulation of the Grain Size Evolution during Isothermal Forging of a TC6 Alloy

    Institute of Scientific and Technical Information of China (English)

    Miaoquan LI; Shankun XUE; Aiming XIONG; Shenghui CHEN

    2005-01-01

    Hot compression was conducted at a Thermecmaster-Z simulator, at deformation temperatures of 800~1040℃, with strain rates of 0.001~50 s-1 and height reduction of 50%. Grain size of the prior α phase was measured with a Leica LABOR-LUX12MFS/ST microscope to which QUANTIMET 500 software for image analysis for quantitative metallography was linked. According to the present experimental data, a constitutive relationship for a TC6 alloy and a model for grain size of the prior α phase were established based on the Arrhenius' equation and the Yada's equation,respectively. By finite element (FE) simulation, deformation distribution was determined for isothermal forging of a TC6 aerofoil blade at temperatures of 860~940℃ and hammer velocities of 9~3000.0 mm/min. Meanwhile, the grain size of the prior α phase is simulated during isothermal forging of the TC6 aerofoil blade, by combining FE outputs with the present grain size model. The present results illustrate the grain size and its distribution in the prior α phase during the isothermal forging of the TC6 aerofoil blade. The simulated results show that the height reduction, deformation temperature, and hammer velocity have significant effects on distribution of the equivalent strain and the grain size of the prior α phase.

  11. 热锻件常见缺陷及防止方法%Hot Forging Common Defects and Prevention Methods

    Institute of Scientific and Technical Information of China (English)

    曹伟; 孙福勋

    2012-01-01

    The forging quality affects directly the performance of parts and service life. The paper analyses the reason of the heating control of oxidation, improper may cause the decarburization, excessive heat or burn, internal crack, heating distributed defects, of forging process prone to filling discontent, and fold, crack defects ,points out the reasons and puts forward the concrete prevention and solutions, and has important guiding role of ensure product quality and control forgings.%锻件质量的优劣直接影响着零件的性能及使用寿命。本文对加热控制不当可能导致的氧化、脱碳、过热或过烧、内部裂纹、加热不均匀等缺陷,对锻造过程容易出现的充填不满、折叠、裂纹等缺陷进行了研究分析,指出了产生的原因,提出了具体的预防、解决方案,对保证和控制锻件产品质量具有重要的指导作用。

  12. Measurement of choroidal thickness and macular thickness during and after pregnancy

    Institute of Scientific and Technical Information of China (English)

    D?ndü; Melek; Ulusoy; Necati; Duru; Mustafa; Atas; Hasan; Altιnkaynak; Zeynep; Duru; G?khan; A?maz

    2015-01-01

    AIM: To investigate the effect of pregnancy on subfoveal choroidal thickness(SFCT) and macular thickness in both pregnant and not pregnant healthy women.METHODS: Twenty-nine healthy pregnant women in their third trimester and 36 age-matched healthy women were enrolled in a prospective, cross-sectional study.Foveal and parafoveal thickness in the four quadrants and SFCT were measured by optical coherence tomography(OCT) in the healthy pregnant women(i.e.study group) and healthy women(i.e. control group).OCT measurements were again measured 3mo after delivery in the study group.RESULTS: Mean SFCT measurements in the control group, pregnant women of the study group, and after delivery of the study group were 320.86 ±59.18 μm,387.97 ±59.91 μm, and 332.40 ±26.03 μm, respectively.There was a statistically significant difference in the mean SFCT values between pregnant women of the study group and the control group(P =0.000). Foveal and parafoveal thickness values were not statistically significant in either the study or control group.CONCLUSION: SFCT increases during pregnancy and returns to normal range in the three months after delivery. Macular thickness does not show any change during pregnancy.

  13. Macular choroidal thickness in unilateral amblyopic children.

    Science.gov (United States)

    Xu, Jinling; Zheng, Jingwei; Yu, Shujuan; Sun, Zuhua; Zheng, Weiwei; Qu, Peng; Chen, Yuanyuan; Chen, Wuhe; Yu, Xinping

    2014-10-14

    To investigate the choroidal thickness (CT) in children with amblyopia through spectral-domain optical coherence tomography (SD-OCT). Thirty-seven children with unilateral amblyopia and 22 children with normal vision participated in the study. Cross-sectional images of the choroid of evaluated eyes were obtained by SD-OCT. The choroidal thickness was measured directly below the fovea and at eight other locations: 1 and 2 mm superior, temporal, inferior, and nasal to the fovea. The researchers compared the choroidal thickness among amblyopic eyes, fellow eyes of children with amblyopia, and the eyes of children with normal vision. Age, sex, refractive error, axial length, and best-corrected visual acuity were also recorded. A paired t-test was used to compare measurements between amblyopic eyes and fellow eyes in patients with amblyopia. A generalized estimating equation (GEE) was used to compare measurements among amblyopic eyes, fellow eyes, and control eyes, adjusting for the possible effects of age, sex, and axial length on CT. The correlation between choroidal thickness and other continuous variables was determined using the Pearson correlation coefficient. The choroidal thickness at the fovea, 1 and 2 mm superior, 1 mm inferior, 1 mm nasal, and 1 mm temporal to the fovea was greater in amblyopic eyes and in fellow eyes of children with amblyopia than in the eyes of children with normal vision. The choroidal thickness at the fovea and 2 mm nasal to the fovea in amblyopic eyes was greater (P = 0.002, P = 0.043) than in the fellow eyes of the children with amblyopia. The subfoveal CT in amblyopic eyes negatively correlated with axial length (r = -0.501, P = 0.002), but did not correlate with spherical equivalent, logMAR visual acuity, or age. In the subfoveal area, the choroid was thicker in amblyopic eyes than in fellow eyes in children with amblyopia. Furthermore, differences were found in the choroidal thickness in both eyes of children with amblyopia compared

  14. Huge thick conglomerate movement induced by full thick longwall mining huge thick coal seam

    Institute of Scientific and Technical Information of China (English)

    Ma Liqiang; Qiu Xiaoxiang; Dong Tao; Zhang Jixiong; Huang Yanli

    2012-01-01

    A discrete elemental method was used to study the thickness of conglomerate layer in a full thick seam mining activities under the influence of the law,pointing out the thickness of the conglomerate at different seam mining,and during the destruction and instability of existing state of laws.At 21141 thick seam mining,the face toward the direction of separation between the thick layer of conglomerate rock and the next bit after reaching its maximum capacity due to pull from the bottom of the plastic zone,formed a stratified and hierarchical down collapse.The shape of caving area is a "triangular block",the length of the plastic zone and face advancement from the linear fit between the height of the plastic zone and the advancing face is a quadratic function of distance,while the top layer of thick gravel layer is the overall bending subsidence trend.Tilting the direction of the face,a thick gob of collapsed conglomerate layer is formed in the coal gob entity on both sides of the thick conglomerate at the top of the overall fracture morphology performance,thus forming a mutual extrusion of articulated block structure.The instability,separation and balance of the thick conglomerate layer in the hinged block stope stress leads to abnormal occurrence of rock burst induced by face as the major factor in the accident.This research reveals the form of stress distribution in the destroyed layer of the thick conglomerate rock,analyzes the stope law of coupling for the pressure burst behavior law for the mining work face,and the choice of preventive measures to provide a theoretical basis and implementation.

  15. Effects of Forged Stock and Pure Aluminum Coating on Cryogenic Performance of Heat Treated Aluminum Mirrors

    Science.gov (United States)

    Toland, Ronald; Ohl, Raymond G.; Barthelmy, Michael P.; Zewari, S. Wahid; Greenhouse, Matthew A.; MacKenty, John W.

    2003-01-01

    In spite of its baseline mechanical stress relief, aluminum 6061-T651 harbors some residual stress that may relieve and distort mirror figure to unacceptable levels at cryogenic operating temperatures unless relieved during fabrication. Cryogenic instruments using aluminum mirrors for both ground-based and space IR astronomy have employed a variety of heat treatment formulae, with mixed results. We present the results of an on-going test program designed to empirically determine the effects of different stress relief procedures for aluminum mirrors. Earlier test results identified a preferred heat treatment for flat and spherical mirrors diamond turned from blanks cut out of Al6061-T651 plate stock. Further tests have been performed on mirrors from forged stock and one set from plate stock coated with Alumiplate(TM) aluminum coating to measure the effect of these variables on cryogenic performance. The mirrors are tested for figure error and radius of curvature at room temperature and at 80 K for three thermal cycles. We correlate the results of our optical testing with heat treatment and metallographic data.

  16. DETERMINATION OF THE OPTIMAL TEMPERING TEMPERATURE IN HARD FACING OF THE FORGING DIES

    Directory of Open Access Journals (Sweden)

    Milan Mutavdžić

    2012-06-01

    Full Text Available Here is analyzed selection of the optimal technology for heat treatment during the reparation of the damaged forging dies. Those tools are manufactured from alloyed tool steels for operation at elevated temperatures. Those steels are prone to self-hardening, so in reparatory hard-facing they must be preheated, additionally heated and tempered. During the tempering, in temperature interval 500-600°C, a secondary increase of hardness and decrease of impact toughness occurs, the so-called reversible tempering brittleness. Here is shown that it can be avoided by application of metallurgical and technological measures. Metallurgical measures assume adequate selection of steels. Since the considered steels are per se prone to tempering brittleness, we conducted experimental investigations to define the technological measures to avoid it. Tests on models were conducted: tempering from different temperatures, slow heating and cooling in still air. Hardness measurements showed that at 520°C, the secondary increase of hardness occurs, with drop of the impact toughness. Additional hard-facing tests included samples tempered at various regimes. Samples were prepared for mechanical and metallographic investigations. Results presented illustrate influence of additional heat treatment on structure, hardness and mechanical properties of the hard-faced layers. This enabled establishing the possibility of avoiding the tempering brittleness through technological measures.

  17. Determination of the optimal tempering temperature in hard facing of the forging dies

    Directory of Open Access Journals (Sweden)

    Milan Mutavdžić

    2012-05-01

    Full Text Available Here is analyzed selection of the optimal technology for heat treatment during the reparation of the damaged forging dies. Those tools are manufactured from alloyed tool steels for operation at elevated temperatures. Those steels are prone to self-hardening, so in reparatory hard-facing they must be preheated, additionally heated and tempered. During the tempering, in temperature interval 500-600°C, a secondary increase of hardness and decrease of impact toughness occurs, the so-called reversible tempering brittleness. Here is shown that it can be avoided by application of metallurgical and technological measures. Metallurgical measures assume adequate selection of steels. Since the considered steels are per se prone to tempering brittleness, we conducted experimental investigations to define the technological measures to avoid it. Tests on models were conducted: tempering from different temperatures, slow heating and cooling in still air. Hardness measurements showed that at 520°C, the secondary increase of hardness occurs, with drop of the impact toughness. Additional hard-facing tests included samples tempered at various regimes. Samples were prepared for mechanical and metallographic investigations. Results presented illustrate influence of additional heat treatment on structure, hardness and mechanical properties of the hard-faced layers. This enabled establishing the possibility of avoiding the tempering brittleness through technological measures. 

  18. Characteristics comparison of weld metal zones welded to cast and forged steels for piston crown material

    Science.gov (United States)

    Moon, Kyung-Man; Kim, Yun-Hae; Lee, Myeong-Hoon; Baek, Tae-Sil

    2015-03-01

    An optimum repair welding for the piston crown which is one of the engine parts exposed to the combustion chamber is considered to be very important to prolong the engine lifetime from an economical point of view. In this study, two types of filler metals such as 1.25Cr-0.5Mo, 0.5Mo were welded with SMAW method and the other two types of filler metals such as Inconel 625 and 718 were welded with GTAW method, respectively, and the used base metals were the cast and forged steels of the piston crown material. The weld metal zones welded with Inconel 625 and 718 filler metals exhibited higher corrosion resistance compared to 1.25Cr-0.5Mo and 0.5Mo filler metals. In particular, the weld metal zone welded with Inconel 718 and 0.5Mo, filler metals indicated the best and worst corrosion resistance, respectively. Consequently, it is suggested that the corrosion resistance of the weld metal zone surely depends on the chemical components of each filler metal and welding method irrespective of the types of piston crown material.

  19. The evolving role of health educators in advancing patient safety: forging partnerships and leading change.

    Science.gov (United States)

    Mercurio, Annette

    2007-04-01

    At least 1.5 million preventable injuries because of adverse drug events occur in the United States each year, according to an Institute of Medicine report. IOM and other organizations at the forefront of health care improvement emphasize that stronger partnerships between patients, their families, and health care providers are necessary to make health care safer. Health educators possess a skill set and an ethical framework that effectively equip them to advance patient and family-centered care and contribute in other significant ways to a safer health care system. Health educators in clinical settings are playing varied and significant roles in advancing patient safety. They are removing barriers to clear communication and forging partnerships between patients, their families, and staff. Health educators are leading patient safety culture change within their institutions and contributing to the shift from provider-centric to patient-centric systems. To expand their impact in improving patient safety, health educators in clinical settings are participating in public awareness campaigns. In seeking to enhance patient safety, health educators face a number of challenges. To successfully manage those, health educators must expand their knowledge, broaden connections, and engage patients and families in meaningful ways.

  20. An investigation of deformed microstructure and mechanical properties of Zircaloy-4 processed through multiaxial forging

    Energy Technology Data Exchange (ETDEWEB)

    Fuloria, Devasri; Nageswararao, P. [Department of Metallurgical and Materials Engineering & Centre of Nanotechnology, IIT Roorkee, Roorkee 247667 (India); Jayaganthan, R., E-mail: rjayafmt@iitr.ernet.in [Department of Metallurgical and Materials Engineering & Centre of Nanotechnology, IIT Roorkee, Roorkee 247667 (India); Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036 (India); Jha, S. [Nuclear Fuel Complex Limited, Hyderabad 501301 (India); Srivastava, D. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 40085 (India)

    2016-04-15

    In the present work, the mechanical behavior of Zircaloy-4 subjected to various deformation strains by multiaxial forging (MAF) at cryogenic temperature (CT) was investigated. The alloy was strained up to different number of cycles, viz., 6 cycles, 9 cycles, and 12 cycles at cumulative strains of 2.96, 4.44, and 5.91, respectively. The mechanical properties of the alloy were investigated by performing the universal tensile test and the Vickers hardness test. Both the test showed improvement in the ultimate tensile strength and hardness value by 51% and 26%, respectively, at the highest cumulative strain of 5.91. The electron backscattered diffraction (EBSD) measurement and transmission electron microscopy (TEM) were used for analyzing the deformed microstructure. The microstructures of the alloy underwent deformation at various cumulative strains/cycles showed grain refinement with the evolution of shear and twin bands that were highest for the alloy deformed at the highest number of cycles. The effective grain refinement was due to twins formation and their intersection, which led to the improvement in mechanical properties of the MAFed alloy, as observed in the present work. - Highlights: • Zircaloy-4 was subjected to MAF at cryogenic temperature. • Microstructural evolution was studied through EBSD and TEM. • Deformed microstructure was marked with various types of twinning and shear banding. • Twins formations are responsible for effective grain refinement and enhanced mechanical properties.

  1. Quantifying performance of ultrasonic immersion inspection using phased arrays for curvilinear disc forgings

    Science.gov (United States)

    Brown, Roy H.; Dobson, Jeff; Pierce, S. Gareth; Dutton, Ben; Collison, Ian

    2017-02-01

    Use of full-matrix capture (FMC), combined with the total focusing method (TFM), has been shown to provide improvements to flaw sensitivity within components of irregular geometry. Ultrasonic immersion inspection of aerospace discs requires strict specifications to ensure full coverage - one of which is that all surfaces should be machined flat. The ability to detect defects through curved surfaces, with an equivalent sensitivity to that obtained through flat surfaces could bring many advantages. In this work, the relationship between surface curvature and sensitivity to standard defects was quantified for various front wall radii. Phased array FMC immersion inspection of curved components was simulated using finite element modelling, then visualized using surface-compensated focusing techniques. This includes the use of BRAIN software developed at the University of Bristol for production of TFM images. Modelling results were compared to experimental data from a series of test blocks with a range of curvatures, containing standard defects. The sensitivity to defects is evaluated by comparing the performance to conventional methods. Results are used to highlight the benefits and limitations of these methods relating to the application area of aerospace engine disc forgings.

  2. Texture evolution in upset-forged P/M and wrought tantalum: Experimentation and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Bingert, J.F.; Desch, P.B.; Bingert, S.R.; Maudlin, P.J.; Tome, C.N.

    1997-11-01

    Preferred orientations in polycrystalline materials can significantly affect their physical and mechanical response through the retention of anisotropic properties inherent to the single crystal. In this study the texture evolution in upset-forged PIM and wrought tantalum was measured as a function of initial texture, compressive strain, and relative position in the pressing. A <001>/<111> duplex fiber texture parallel to the compression axis was generally observed, with varying degrees of a radial component evident in the wrought material. The development of deformation textures derives from restricted crystallographic slip conditions that generate lattice rotations, and these grain reorientations can be modeled as a function of the prescribed deformation gradient. Texture development was simulated for equivalent deformations using both a modified Taylor approach and a viscoplastic self-consistent (VPSC) model. A comparison between the predicted evolution and experimental results shows a good correlation with the texture components, but an overly sharp prediction at large strains from both the Taylor and VPSC models.

  3. Seasonal food use by white-tailed deer at Valley Forge National Historical Park, Pennsylvania, USA

    Science.gov (United States)

    Cypher, Brian L.; Yahner, Richard H.; Cypher, Ellen A.

    1988-03-01

    Food habits of white-tailed deer ( Odocoileus virginianus) were examined from January to November 1984 via fecal-pellet analysis at Valley Forge National Historical Park (VFNHP), which represents an “island” habitat for deer surrounded by extensive urbanization, in southeastern Pennsylvania. In addition, use of fields by deer was compared to food habits. Herbaceous vegetation (forbs, leaves of woody plants, and conifer needles) was the predominant food type in all seasons except fall. Acorns and graminoids (grasses and sedges) were important food resources in fall and spring, respectively. Use of woody browse (twigs) was similar among seasons. Field use was relatively high during fall, winter without snow cover (food resources in fields were readily available. In contrast, use of fields was lowest in summer when preferred woodland foods were available and in winter with snow cover when food in fields was not readily accessible. Patterns of food-type use by deer at VFNHP indicate the year-round importance of nonwoody foods and field habitats to deer populations on public lands such as national parks in the northeastern United States.

  4. Microstructural, mechanical, corrosion and cytotoxicity characterization of the hot forged FeMn30(wt.%) alloy.

    Science.gov (United States)

    Čapek, Jaroslav; Kubásek, Jiří; Vojtěch, Dalibor; Jablonská, Eva; Lipov, Jan; Ruml, Tomáš

    2016-01-01

    An interest in biodegradable metallic materials has been increasing in the last two decades. Besides magnesium based materials, iron-manganese alloys have been considered as possible candidates for fabrication of biodegradable stents and orthopedic implants. In this study, we prepared a hot forged FeMn30 (wt.%) alloy and investigated its microstructural, mechanical and corrosion characteristics as well as cytotoxicity towards mouse L 929 fibroblasts. The obtained results were compared with those of iron. The FeMn30 alloy was composed of antiferromagnetic γ-austenite and ε-martensite phases and possessed better mechanical properties than iron and even that of 316 L steel. The potentiodynamic measurements in simulated body fluids showed that alloying with manganese lowered the free corrosion potential and enhanced the corrosion rate, compared to iron. On the other hand, the corrosion rate of FeMn30 obtained by a semi-static immersion test was significantly lower than that of iron, most likely due to a higher degree of alkalization in sample surrounding. The presence of manganese in the alloy slightly enhanced toxicity towards the L 929 cells; however, the toxicity did not exceed the allowed limit and FeMn30 alloy fulfilled the requirements of the ISO 10993-5 standard.

  5. Closed Die Deformation Behavior of Cylindrical Iron-Alumina Metal Matrix Composites During Cold Sinter Forging

    Science.gov (United States)

    Prasanna Kumar, Undeti Jacob; Gupta, Pallav; Jha, Arun Kant; Kumar, Devendra

    2016-10-01

    The present paper aims to study the closed die deformation behavior of cylindrical Fe-Al2O3 metal matrix composites (MMCs). Closed die was manufactured by machining the high carbon steel block followed by oil quenching and then finishing. Samples sintered at a temperature of 1100 °C for 1 h were characterized with X-ray diffraction and scanning electron microscopy, which showed the formation of Fe, Al2O3 and nano size FeAl2O4 phases respectively. Density and hardness of the composite samples were determined after sintering. Closed die deformation studies of the prepared composite samples were carried under three different interfacial frictional conditions i.e. dry, solid lubricating and liquid lubricating. Hardness, density and metallographic characterizations were also done for the deformed samples. On comparing the micrographs of the samples before and after deformation it was revealed that in deformed specimens recrystallization has taken place due to the difference in the energy between the strained iron matrix and unstrained alumina reinforcement during closed die forging process. Experimental density of the samples was also verified with the theoretical density using the standard equations. It is expected that the results of the present investigations will be helpful in developing quality MMC components for wide industrial applications.

  6. Validation of Cooper's ligament thickness in software breast phantoms

    Science.gov (United States)

    Kuperavage, Adam J.; Imran, Abdullah-Al-Zubaer; Bakic, Predrag R.; Maidment, Andrew; Pokrajac, David D.

    2017-03-01

    Anthropomorphic breast phantoms are important tools for a wide range of tasks including pre-clinical validation of novel imaging techniques. In order to improve the realism in the phantoms, assessment of simulated anatomical structures is crucial. Thickness of simulated Cooper's ligaments influences the percentage of dense tissue, as well as qualitative and quantitative properties of simulated images. We introduce three methods (2-dimensional watershed, 3-dimensional watershed, and facet counting) to assess the thickness of the simulated Cooper's ligaments in the breast phantoms. For the validation of simulated phantoms, the thickness of ligaments has been measured and compared with the input thickness values. These included a total of 64 phantoms with nominal ligament thicknesses of 200, 400, 600, and 800 μm. The 2-dimensional and 3-dimensional watershed transformations were performed to obtain the median skeleton of the ligaments. In the 2-dimensional watershed, the median skeleton was found cross-section by cross-section, while the skeleton was found for the entire 3-dimensional space in the 3-dimensional watershed. The thickness was calculated by taking the ratio of the total volume of ligaments and the volume of median skeleton. In the facet counting method, the ligament thickness was estimated as a ratio between estimated ligaments' volume and average ligaments' surface area. We demonstrated that the 2-dimensional watershed technique overestimates the ligament thickness. Good agreement was found between the facet counting technique and the 3-dimensional watershed for assessing thickness. The proposed techniques are applicable for ligaments' thickness estimation on clinical breast images, provided segmentation of Cooper's ligaments has been performed.

  7. Peripapillary choroidal thickness in childhood.

    Science.gov (United States)

    Read, Scott A; Alonso-Caneiro, David; Vincent, Stephen J; Collins, Michael J

    2015-06-01

    Changes in the thickness of the invivo peripapillary choroid have been documented in a range of ocular conditions in adults; however, choroidal thickness in the peripapillary region of children has not been examined in detail. This study therefore aimed to investigate the thickness of the peripapillary choroid and the overlying retinal nerve fibre layer (RNFL) in a population of normal children with a range of refractive errors. Ninety-three children (37 myopes and 56 non-myopes) aged between 11 and 16 years, had measurements of peripapillary choroidal and RNFL thickness derived from enhanced depth imaging optical coherence tomography images (EDI-OCT, Heidelberg Spectralis). The average thickness was determined in a series of five 0.25 mm width concentric annuli (each divided into 8 equal sized 45° sectors) centred on the optic nerve head boundary, accounting for individual ocular magnification factors and the disc-fovea angle. Significant variations in peripapillary choroidal thickness were found to occur with both annulus location (p choroid (mean 77 ± 16 μm) and the outermost annulus, the thickest choroid (191 ± 52 μm). The choroid was thinnest inferior to the optic nerve head (139 ± 38 μm) and was thickest in the superior temporal sector (157 ± 40 μm). Significant differences in the distribution of choroidal thickness were also associated with myopia, with myopic children having significantly thinner choroids in the inner and outer annuli of the nasal and temporal sectors respectively (p thickness also varied significantly with annulus location and sector (p thickness distribution associated with refractive error. This study establishes the normal variations in the thickness of the peripapillary choroid with radial distance and azimuthal angle from the optic nerve head boundary. A significant thinning of the peripapillary choroid associated with myopia in childhood was also observed in both nasal and temporal regions. The changes in peripapillary RNFL

  8. Backward Extrusion of Aluminum Alloy Sections Used in Aircraft Structural Components / Wyciskanie Przeciwbieżne Kształtowników Ze Stopów Aluminium Stosowanych Na Elementy Konstrukcji Lotniczych

    Directory of Open Access Journals (Sweden)

    Pawłowska B.

    2015-12-01

    Full Text Available The paper presents an analysis of selected aluminum alloys as structural materials used in production of aircraft parts as well as specification of technological parameters of Al alloys extrusion on a backward press with their effect on mechanical properties, microstructure and quality of the final product. Upsetting tests with backward extrusion complex cross-sectional profile tests were conducted on aluminum alloys 7075, 2024, 2099. Based on the results, specifications of forging in the form of unit stress - effective strain relations were determined using logarithmic deformation index, allowing proper choice of extrusion parameters. The range of temperatures for hot plastic treatment along with range of extrusion rate for the analyzed thin-walled aircraft profiles were determined. Tests were also conducted on the microstructure of Al alloys in the initial state as well as after the extrusion process had been completed. It has been proved that the proper choice of parameters in the case of a specific profile extruded from Aluminum alloys 2024, 7075, 2099, allows the manufacturing of products of complex crosssections and the quality required in aerospace industry. This has been demonstrated on the example of complex cross-sectional profiles using elements of varied wall thickness.

  9. 机械自紧厚壁圆筒塑性半径的计算%Calculation of Plastic Radius for Thick-Walled Cylinders of Mechanical Autofrettage

    Institute of Scientific and Technical Information of China (English)

    常列珍; 潘玉田; 马新谋; 潘丹阳

    2011-01-01

    机械自紧是依靠冲头同身管内径的过盈量使身管内壁产生塑性变形,提高承载能力,达到自紧的目的.准确建立冲头过盈量与塑性半径之间的关系,才能准确地预测自紧度.为此,利用合理的简化假设,通过对冲头进行弹性分析和对厚壁圆筒进行塑性分析,利用机械自紧在加载过程中冲头圆柱段和厚壁圆筒接触处径向应力相等这一边界条件,推导出了过盈量与塑性半径之间的计算公式,从该公式可直接由过盈量求出塑性半径,由塑性半径便可预测出机械自紧厚壁圆筒的自紧度.为了验证公式的正确性,对10种不同过盈量的机械自紧过程进行了数值模拟,理论计算与数值模拟的结果进行比较,发现理论计算结果与数值模拟的结果比较吻合.%The swage autofrettage barrel is formed depending on the depth of plastic deformation since the diameter of the tool is slightly larger than the barrel inner diameter. The barrel forged in this way can withstand large internal pressures. In order to calculate the degree of autofrettage, the relation between the interference and the plastic radius must be accurately investigated. In loading process, the radial stress of cylindrical section of swage and thick-walled cylinder contact section is equal. By using this boundary condition, an elastic analysis for swage and a plastic analysis for thick-walled cylinder were conducted, and formulas were obtained for calculating excess and plastic radius. Knowing interference, the plastic radius could be calculated directly and the tight tolerance could be pre-estimated by using the plastic radius. To verify the accuracy of the formula, the process of mechanical autofrettage with ten kind different interferences were simulated. Calculated plastic radius agreed well with the results of numerical simulation.

  10. Stress measurement in thick plates using nonlinear ultrasonics

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, Zeynab, E-mail: zabbas5@uic.edu, E-mail: dozevin@uic.edu; Ozevin, Didem, E-mail: zabbas5@uic.edu, E-mail: dozevin@uic.edu [University of Illinois at Chicago, Civil and Materials Engineering, 842 W Taylor Street ERF 2095, Chicago, IL 60607 (United States)

    2015-03-31

    In this paper the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded thick steel plates using fundamental theory of nonlinear ultrasonics is investigated in order to measure the stress state at a given cross section. The measurement concept is based on phased array placement of ultrasonic transmitter-receiver to scan three angles of a given cross section using Rayleigh waves. The change in the ultrasonic data in thick steel plates is influenced by normal and shear stresses; therefore, three measurements are needed to solve the equations simultaneously. Different thickness plates are studied in order to understand the interaction of Rayleigh wave penetration depth and shear stress. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The influences of plate thickness and ultrasonic frequency on the identification of stress tensor are numerically studied in 3D structural geometry and Murnaghan material model. The experimental component of this study includes uniaxial loading of the plate while measuring ultrasonic wave at three directions (perpendicular, parallel and angled to the loading direction). Instead of rotating transmitter-receiver pair for each test, a device capable of measuring the three angles is designed.

  11. Stress measurement in thick plates using nonlinear ultrasonics

    Science.gov (United States)

    Abbasi, Zeynab; Ozevin, Didem

    2015-03-01

    In this paper the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded thick steel plates using fundamental theory of nonlinear ultrasonics is investigated in order to measure the stress state at a given cross section. The measurement concept is based on phased array placement of ultrasonic transmitter-receiver to scan three angles of a given cross section using Rayleigh waves. The change in the ultrasonic data in thick steel plates is influenced by normal and shear stresses; therefore, three measurements are needed to solve the equations simultaneously. Different thickness plates are studied in order to understand the interaction of Rayleigh wave penetration depth and shear stress. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The influences of plate thickness and ultrasonic frequency on the identification of stress tensor are numerically studied in 3D structural geometry and Murnaghan material model. The experimental component of this study includes uniaxial loading of the plate while measuring ultrasonic wave at three directions (perpendicular, parallel and angled to the loading direction). Instead of rotating transmitter-receiver pair for each test, a device capable of measuring the three angles is designed.

  12. Laser cutting of thick sheet metals: Residual stress analysis

    Science.gov (United States)

    Arif, A. F. M.; Yilbas, B. S.; Aleem, B. J. Abdul

    2009-04-01

    Laser cutting of tailored blanks from a thick mild steel sheet is considered. Temperature and stress field in the cutting sections are modeled using the finite element method. The residual stress developed in the cutting section is determined using the X-ray diffraction (XRD) technique and is compared with the predictions. The structural and morphological changes in the cut section are examined using the optical microscopy and scanning electron microscopy (SEM). It is found that temperature and von Mises stress increase sharply in the cutting section, particularly in the direction normal to the cutting direction. The residual stress remains high in the region close to the cutting section.

  13. 热模锻传动轴滑动轴承承载力分析%Analysis on the Load Capacity of Slip Bearing for Cardan Shaft of Hot Die Forging Press

    Institute of Scientific and Technical Information of China (English)

    魏田华; 殷文齐; 杜建伟

    2015-01-01

    The essay introduces the Reynolds equation used to calculate the load capacity of oil film of slip bearing which is in dynamic pressure and radial type for the cardan shaft of the hot die forging press. The key dimension of the bearing is designed by Reynolds model. The finite element model is created based upon such dynamic pressure and radial slip bearing, the result of which analyse the pressure distribution on the oil film and variation of load capacity under different minimum oil film thickness. It concludes the maximum load capacity and the corresponding different minimum oil film thickness.%介绍用于动压径向滑动轴承油膜承载能力计算的雷诺方程。根据雷诺计算模型确定某热模锻压机传动轴滑动轴承的关键尺寸,并以该动压径向滑动轴承为基础,建立有限元模型,分析在不同最小油膜厚度下油膜上的压力分布和承载力变化,分析得出滑动轴承的最大承载能力及其所对应的最小油膜厚度。

  14. Application of the Manipulator in Forging Production%机械手在锻压生产中的应用研究

    Institute of Scientific and Technical Information of China (English)

    黄银花; 赵仕奇

    2013-01-01

      为了提高我国锻压生产的自动化水平,减少加工过程对操作人员的危害,实现绿色锻压,有必要根据我国锻压行业的现状,应用锻压机械手代替人工完成锻压生产过程中的上料、翻转、下料等危险性高、简单重复性、劳动强度高的工作,以提高生产自动化程度,提高生产率,提高产品一致性。在分析锻压生产现状的基础上,分析锻压过程中人工操作的动作流程,提出锻压机械手的结构形式、工作原理及运动方案,并阐述其应用的意义。%In order to improve the automation level of forging in our country,reduce harm to operators,realize green forging,it is necessary to combine the current situation of forging industry in our country,applying forging manipulator to replace the manual forging process for the production of feed,turning,cutting and other high risk,high labor intensity,simple repetitive work. This will improve the production automation level and product consistency,increase productivity. Based on the analysis of the present situation of forging production,the artificial action process of forging was analyzed. The structure,working principle and motion scheme of the applied forging manipulator were put forward,and the significance of its application was expounded.

  15. Laboratory and Performance Studies of Anti-wear Coatings Deposited on Nitrided Surfaces of Tools used in an Industrial Hot Die Forging Process

    Science.gov (United States)

    Hawryluk, Marek; Widomski, Paweł; Smolik, Jerzy; Kaszuba, Marcin; Ziemba, Jacek; Gronostajski, Zbigniew

    2017-04-01

    The paper presents the results of laboratory studies performed on produced anti-wear coatings as well as the results of performance tests conducted on tools with these coatings in industrial conditions, in the process of hot die forging. Three different coatings were selected: AlCrTiSiN, Cr/CrN and AlCrTiN, deposited by means of the vacuum-arc method on test samples as well as forging tools used in the hot forging process of a lid. The first part of the paper discusses the results of the studies performed in laboratory conditions, which included: surface morphology by means of SEM, hardness and Young modulus measurements, determination of the chemical composition by means of the EDS method, adhesion tests by means of the scratch method and tribological tests by means of the ball-on-disk method. The obtained results were correlated and applied in the analysis of the performance tests on forging punches with these coatings at an early stage of their performance (up to 4000 produced forgings), which were tested on 19 tools, of which 3 representatives were selected for each coating. A thorough analysis was performed of the wear phenomena and mechanisms and the manner of wear of hybrid layers as well as their resistance to the particular destructive mechanisms. Based on the performed laboratory and performance studies as well as their analysis, it was possible to select the optimal hybrid layer, which enables an increase in the durability of forging tools used in industrial hot die forging processes. The preliminary results showed that the best results for the whole working surface of the tool were obtained for the Cr/CrN layer, which characterizes in high adhesion as well as a lower Young modulus and hardness. In the case of high pressures and the correlated friction, better results were obtained for the AlCrTiN coating, which, besides its good adhesion properties, also exhibited the highest frictional resistance.

  16. Velocity Field and Variation of Wall Thickness During Tube Dieless Upsetting

    Institute of Scientific and Technical Information of China (English)

    王忠堂; 栾瑰馥; 张士宏

    2004-01-01

    Theoretical analyses show that the variation of wall thickness is in direct proportion to outer-diameter, inter-diameter, and (√1 + Rs) (Rs is sectional increase ratio of tube), the theoretical calculated results of wall thickness during tube dieless upsetting are very approximate to the experimental one. As the width of deformation field increases, both the variation of wall thickness and the derivative of wall thickness variation to width of deformation field (tf/to) reduce.

  17. 特大断面厚煤顶开切眼复合桁架锚索围岩控制技术%The application of pre-stress compound truss cable in set-up room with large cross section thick coal roof

    Institute of Scientific and Technical Information of China (English)

    何富连; 栗建平; 蒋红军; 许磊; 高升; 肖殿才

    2012-01-01

    针对五家沟煤矿断面达9.0m宽,3.5m高的留厚煤顶特大断面切眼支护难题,采用复合桁架锚索支护系统对该综放面切眼进行支护.结合现场实际的地质条件确定了锚索长度、锚索角度、孔口帮距等主要的支护参数,形成了最终的支护方案.运用数值模拟软件对原支护方案和现支护方案进行了数值模拟分析对比,分析得出采用预应力复合桁架锚索支护系统控制该特大端面开切眼围岩是安全可靠的.该支护方案在现场5203综放面开切眼试验取得成功,巷道断面收敛率小,为相似地质条件下的厚煤顶特大断面开切眼围岩控制提供了借鉴意义.%For the support problem of set-up room to be 9. 0m wide and 3. 5m high with thick coal roof in Wujiagou mine, the compound truss cable support system is adopted to control the set-up room surrounding rock. Combined with the flied actual geological conditions,the main support parameters such us cable length,cable angle and distance between orifice and side are determined through engineering analogy and the final support scheme is formed. The numerical simulation analysis comparison is made between the designed scheme and the original one, the application of pre-stressed compound truss cable system used to control the surrounding rock of large cross section set-up room is reliable and safe. The support scheme is successfully tested at set-up room No. 5203 in Wujiagou mine. The set-up room deformation is small,and this kind of support technology can be widely used in the similar set-up rooms.

  18. 连杆无飞边锻造工艺及模具系统研究%Flashless Forging Process and Tool System of Connecting Rod

    Institute of Scientific and Technical Information of China (English)

    刘雅辉; 刘淑梅; 何文涛; 于秋华

    2014-01-01

    目的:研究连杆无飞边锻造工艺,以及闭模锻造过程中中间工序件的设计和所需的模具系统。方法通过建立有限元模型,分析连杆的预锻和终锻过程中金属流动长度、成形载荷和模具寿命,为模具设计提供数据支持。结果数值模拟结果表明金属充模效果良好;连杆大端主要在预锻中成形,而连杆小端和杆部主要在终锻中成形;预锻和终锻的最大成形载荷分别为437 t 和850 t;连杆大端的模腔圆角为模具失效危险区。结论通过辊锻制坯、预锻分配物料和终锻精密成形,实现了连杆的无飞边锻造。%Objective To investigate the flashless forging process connecting rod, as well as the design of intermediate goods and the die system needed for closed-die forging. Methods Finite element model was estimated to analyze the metal flowing path during pre and final forging, forming load and tool life, which provided data support for the tool design. Re-sults Results of numerical simulation showed that: the metal die-filling was desired; the big end of connecting rod was mainly formed in the pre-forging, whereas small end and stem were mainly formed in the final forging; the maximum form-ing loads of pre and final forging were 437 t and 850 t, respectively; the dangerous zone of tool failure occurred at the big end of connecting rod in the cavity. Conclusion Through rolling for blank preparation, pre-forging for materials distribu-tion and final forging for precision forming, flashless precision forging for connecting rod was achieved.

  19. Tube wall thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, P.R.

    1985-06-21

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  20. Tube wall thickness measurement apparatus

    Science.gov (United States)

    Lagasse, P.R.

    1985-06-21

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  1. Tube wall thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, Paul R. (Santa Fe, NM)

    1987-01-01

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  2. Industrial Process Design for Manufacturing Inconel 718 Extremely Large Forged Rings

    Science.gov (United States)

    Ambielli, John F.

    2011-12-01

    Inconel 718 is a Ni-Fe-based superalloy that has been central to the gas turbine industry since its discovery in 1963. While much more difficult to process than carbon or stainless steels, among its superalloy peers Inconel 718 has relatively high forgeability and has been used to make discs, rings, shells, and structural components. A metal forming process design algorithm is presented to incorporate key criteria relevant to superalloy processing. This algorithm was applied to conceptual forging and heat treating extremely large rings of Inconel 718 of diameter 1956 mm (77in) and weight 3252 kg (7155 lb). A 3-stage standard thermomechanical (TMP) processing was used, where Stage 1 strain varied from 0.1190 to 0.2941, Stage 2 from 0.0208 to 0.0357 and Stage 3 from 0.0440 to 0.0940. This was followed by heat treatment of a solution anneal (954°C/1750°F for 4 hour hold), air cool, then a double aging (718°C/1325°F for 8 hour hold; furnace cool to 621°C/1150°F 56°C/100°F per hr; 18 hour total time for both steps). Preliminary mechanical testing was performed. Average yield strength of 951 MPa/138 ksi (longitudinal) and 979 MPa/142 ksi (axial) was achieved. Tensile strengths were 1276 MPa/185 ksi (longitudinal) and 1255 MPa/182 ksi (axial). Elongations and reduction of areas attained were, respectively, 18 (long) and 25 (axial) and 28 (long) and 27 (axial).

  3. FE Simulation Modelling and Exergy Analysis of Conventional Forging Deformation Behaviour of Material Processing

    Directory of Open Access Journals (Sweden)

    Santosh Sanodiya

    2017-03-01

    Full Text Available The present paper examines the deformation behaviour of geometrical specimens of an aluminium alloy undergoing axial compression in a Universal Testing Machine under dry condition. It is observed that researchers have made attempts to investigate alternate specimens for friction calibration. It is found that ring compression test is recommended as the standard test for determination of coefficient of friction, because it gives reliable results. The effect of weight percentage of silicon carbide on microstructure, hardness and upsetting load is studied. The friction factor at die metal interface is evaluated by ring compression tests and its effect on non-uniform deformation is investigated. The experimental results are finally compared with those obtained by FEA simulation and modelling. In order to validate the predictability of these specimens, real experiments on them are carried out. Rings of standard dimensional ratio 6:3:1 in the same machine. Friction predictions from both specimen are found to be in close match, proposed alternate specimen offers a powerful tool for friction prediction in the absence of ring specimen. Some aspects of Exergy calculations have been in the past repeatedly used to quantify the quality and quantity of energy used in thermal energy processes. This attempt to drive a exergy utilization and compare for the first time two entirely different manufacturing processes, material processing by a mechanical method of straining of the material and thermal processing during cold forging of the same mass of the material using exergy formulation as metric. The exergy analysis of material processing is determined by performed work and utilized heat transfer using mechanical and thermal processes

  4. Blade Forging Design Based on the Secondary Development of UG%UG二次开发在叶片锻造中的应用

    Institute of Scientific and Technical Information of China (English)

    魏科; 谢崴; 王高潮

    2011-01-01

    综合运用UG表达式法及UG二次开发工具UG/Open API,UG/Open MenuScript,UG/Open UIStyler和Visual C++ 6.0,根据叶片锻件的加工原理,开发叶片模锻参数化设计系统。在该系统中,叶片锻件和锻模造型易于设计及修改。对提高叶片模具设计的效率、缩短模具开发周期具有较强的实用价值,同时也为后期的叶片模具制造和有限元数值模拟做好了强大的铺垫。%Combined with the method of UG expression and the tools of the UG secondary development including UG/ Open MenuScript, UG/Open UIStyler, UG/Open API and Visual C++ 6.0, blade die forging parametric design system was developed based on the blade forging process theory. In this system, the blade forging and die were easily designed and modified This method brings practical values for improving efficiency of blade forging die design and shortening the die development period, meanwhile, making a strong foundation for the following blade forging die manufacture and simulation by finite element method.

  5. The role of microstructure in the modelling of plastic flow in P/M superalloys at forging temperatures and strain rate

    Science.gov (United States)

    Immarigeon, J. P.

    1984-09-01

    The application of computer aided plasticity analysis to model the deformation of alloys during forging with a view to optimizing the microstructure in forged components is presented. Finite element modelling techniques and a methodology for predicting local changes in grain size as a function of local deformation history predict the final grain sizes in the rim and the bore regions of a disc via process modelling and determines the processing conditions under which an optimum microstructure is produced. The effects of thermomechanical history on the evolution of microstructure in P/M superalloys under isothermal forging conditions and formulation of physically realistic constitutive relations for plastic flow which quantify the effects of the microstructural evolution, thereby allowing the prediction of final microstructure in forgings were studied. Using constant true strain rate uniaxial compression tests, microstructure flow property data were generated at isothermal foring temperatures and strain rates for a number of compacts. Deformation modelling for microstructural control is discussed. It is shown that the rate of change of grain size is an important parameter which governs changes in flow strength and is considered in the formulation of constitutive relations for compacts both in a coarse grained and in a fine grained superplastic condition. A deformation model for grain size and rate sensitive P/M superalloys and a methodology that can be applied to predict grain size distributions in forgings are presented.

  6. Analysis on the Phenomenon of Documentary Image Forging%纪实影像失真现象探析

    Institute of Scientific and Technical Information of China (English)

    周建青; 文倩; 涂雯丹

    2013-01-01

      真实是纪实影像的生命。但是,在纪实影像的创作中,失真现象日益严重。本文分析了当前纪实影像失真的表现及其危害,一是前期拍摄中,为影像完美而失真,违背真实原则;二是后期制作中利用数字软件篡改,纪实影像艺术化,导致诚信危机。在此基础上,提出了从纪实观念、行为、监管、处罚等方面加以强化,防止纪实影像失真泛滥,确保纪实影像真实。%  Truth is the life of documentary image.However, the phenomenon of forging is increasingly serious in the creation of documentary image.This thesis analyzes the manifestation and detriment of present documentary im-age:one is forging for perfect image in shooting and violating the principle of authenticity , and the second is falsif-ying by digital soft in post -production and resulting crisis of integrity .The author proposes that it is necessary to strengthen the documentary concept , behavior, regulation and penalty to prevent against the flood of documentary image forging and ensure the authenticity of documentary image on this basis .

  7. SIMULATION OF 3-D DEFORMATION AND MATERIAL FLOW DURING ROLL FORGING PROCESS USING SYSTEM OF OVAL-ROUND GROOVE

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Basing on the analysis of the traits of the roll forging process, a system-model of computer simulation has been established. Three-dimensional rigid-plastic FEM has been used for the simulation of the deformation process in the oval and round pass rolling, including the entering, rolling, and separating stages. The analysis was conducted using the Deform-3D ver. 5.0 code.The important information concerned with the deformation area characteristic, material fiow, and velocity field has been presented. Otherwise, the location of the neutral plane in the deformation area was shown clearly.

  8. The Effect of Forging Variables on the Supersolvus Heat-Treatment Response of Powder-Metallurgy Nickel-Base Superalloys

    Science.gov (United States)

    2014-12-01

    AFRL-RX-WP-JA-2015-0160 THE EFFECT OF FORGING VARIABLES ON THE SUPERSOLVUS HEAT-TREATMENT RESPONSE OF POWDER-METALLURGY NICKEL -BASE SUPERALLOYS...POWDER-METALLURGY NICKEL - BASE SUPERALLOYS (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR...of Powder-Metallurgy Nickel -Base Superalloys S.L. SEMIATIN, J.M. SHANK, A.R. SHIVELEY, W.M. SAURBER, E.F. GAUSSA, and A.L. PILCHAK The effect of

  9. Numerical Analysis for Precision Roll Forging of Front Axle%前轴精密辊锻成形过程的数值分析

    Institute of Scientific and Technical Information of China (English)

    郑明玉; 喻建军; 沙奔; 陈池; 陈文琳

    2012-01-01

    The three passes roll forging process was simulated for front axle by using the rigid-plastic finite element model. The transformation law of blank, the roll forging torque and the effective stress distribution were analyzed during the three passes roll forging process. The result of the simulation has important significance for guiding the practical production and improving the level of die design.%采用刚塑性有限元模型对前轴辊锻3道次进行了有限元模拟,分析了辊锻过程中坯料的变化规律、等效应力分布及辊锻力矩的变化规律.模拟结果对于指导实际生产,提高模具设计水平具有重要意义.

  10. Numerical Simulation on the Forging Process of Triple Valve%三通阀模锻成形工艺数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    孙艮芝

    2012-01-01

    采用多向模锻工艺成形三通阀,应用Deform-3D软件对多向模锻成形过程进行数值模拟,分析成形缺陷,优化成形工艺方案,为实际生产提供理论指导。%The multi-ram forging method is used to forge the triple valve. Numerical simUlation based on Deform-3D is used to analysis the multi ram forging process. Analysis of the forming defects and optimization of the forming process pro-gram provide theoretical guidance for the actual production.

  11. Eddy current thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, Gary J.; Sinclair, Frank; Soskov, Alexander; Buff, James S.

    2015-06-16

    A sheet of a material is disposed in a melt of the material. The sheet is formed using a cooling plate in one instance. An exciting coil and sensing coil are positioned downstream of the cooling plate. The exciting coil and sensing coil use eddy currents to determine a thickness of the solid sheet on top of the melt.

  12. Characteristics of shell thickness in a slab continuous casting mold

    Institute of Scientific and Technical Information of China (English)

    Di-feng Wu; Shu-sen Cheng; Zi-jian Cheng

    2009-01-01

    The key to reduce shell breakout in the continuous casting process is to control shell thickness in the mold.A numerical simulation on the turbulent flow and heat transfer coupled with solidification in the slab mold using the volume of fluid (VOF) model and the enthalpy-porosity scheme was conducted and the emphasis was put upon the flow effect on the shell thickness profiles in longitudinal and transverse directions.The results show that the jet acts a stronger impingement on the shell of narrow face,which causes a zero-increase of shell thickness in a certain range near the impingement point.The thinnest shell on the slab cross-section locates primarily in the center of the narrow face,and secondly near the comer of the wide face.Nozzle optimization can obviously increase the shell thickness and make it more uniform.

  13. Overweight is not associated with cortical thickness alterations in children

    Directory of Open Access Journals (Sweden)

    Rachel Jane Sharkey

    2015-02-01

    Full Text Available IntroductionSeveral studies report an association between body mass index (BMI and cortical thickness in adults. Some studies demonstrate diffuse cortical thinning in obesity, while others report effects in areas that are associated with self-regulation, such as lateral prefrontal cortex. MethodsThis study used multilevel modelling of data from the NIH Pediatric MRI Data Repository, a mixed longitudinal and cross-sectional database, to examine the relationship between cortical thickness and body weight in children. Cortical thickness was computed at 81,942 vertices of 716 MRI scans from 378 children aged between 4 and 18 years. Body mass index Z score for age was computed for each participant. We preformed vertex-wise statistical analysis of the relationship between cortical thickness and BMI, accounting for age and gender. In addition, cortical thickness was extracted from regions of interest in prefrontal cortex and insula.ResultsNo significant association between cortical thickness and BMI was found, either by statistical parametric mapping or by region of interest analysis. Results remained negative when the analysis was restricted to children aged 12-18.ConclusionsThe correlation between BMI and cortical thickness was not found in this large pediatric sample. The association between BMI and cortical thinning develops after adolescence. This has implications for the nature of the relationship between brain anatomy and weight gain.

  14. Facial soft tissue thickness in North Indian adult population

    Directory of Open Access Journals (Sweden)

    Tanushri Saxena

    2012-01-01

    Full Text Available Objectives: Forensic facial reconstruction is an attempt to reproduce a likeness of facial features of an individual, based on characteristics of the skull, for the purpose of individual identification - The aim of this study was to determine the soft tissue thickness values of individuals of Bareilly population, Uttar Pradesh, India and to evaluate whether these values can help in forensic identification. Study design: A total of 40 individuals (19 males, 21 females were evaluated using spiral computed tomographic (CT scan with 2 mm slice thickness in axial sections and soft tissue thicknesses were measured at seven midfacial anthropological facial landmarks. Results: It was found that facial soft tissue thickness values decreased with age. Soft tissue thickness values were less in females than in males, except at ramus region. Comparing the left and right values in individuals it was found to be not significant. Conclusion: Soft tissue thickness values are an important factor in facial reconstruction and also help in forensic identification of an individual. CT scan gives a good representation of these values and hence is considered an important tool in facial reconstruction- This study has been conducted in North Indian population and further studies with larger sample size can surely add to the data regarding soft tissue thicknesses.

  15. Tube wall thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, P.R.

    1987-01-06

    An apparatus is described for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item, the apparatus comprising: a. a base; b. a first support member having first and second ends, the first end being connected to the base, the first support member having a sufficiently small circumference that the tube can be slid over the first support member; c. a spherical element, the spherical element being connected to the second end of the first support member. The spherical element has a sufficiently small circumference at its equator that the tube can be slid over the spherical element, the spherical element having at its equator a larger circumference than the first support member; d. a second support member having first and second ends, the first end being connected to the base, the second support member being spaced apart form the first support member; e. a positioning element connected to and moveable relative to the second support member; and f. an indicator connected to the positioning element and being moveable thereby to a location proximate the spherical element. The indicator includes a contact ball for contacting the selected standard item and holding it against the spherical element, the contact ball contacting the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item, the rotatable needle being operatively connected to and responsive to the position of the contact ball.

  16. Roll forging die design based on UG secondary development%UG二次开发在辊锻模具设计中的应用

    Institute of Scientific and Technical Information of China (English)

    魏科; 王高潮; 李宁; 夏春林

    2011-01-01

    综合运用UG表达式法及UG二次开发工具UG/Open API、UG/0pen MenuScript、UG/Open UIStyler和Visual C++6.0,根据汽车前轴锻件的加工原理,开发了汽车前轴精制坯辊锻系统.在该系统中,前轴辊锻件和辊锻模参数化造型易于设计及修改,任何汽车前轴设计人员都能够方便的操作.该系统对提高汽车前轴辊锻模具设计的效率、缩短模具开发周期具有较强的实用价值,同时也为后期的辊锻模具制造和有限元模拟做好了强大的铺垫.%Combined with the method of UG expression and the tools of the UG secondary development including UG/Open MenuScript, UG/Open UIStyler, UG/Open API and Visual C+ +6.0,the roll-forging system of precision and billet on automotive front axle was developed based on the front axle forging process theory. In this system, the front axle forging and die was easily modified, and any front axle forging designer could handle it with much convenience.This method brings practical values for improving efficiency of front axle forging die design and shortening the die development period, meanwhile, making a strong fundament for the following roll-forging die production and finite element method.

  17. Research on the Improvement of Mechanical Properties of Shaft Forgings%改善轴类锻件力学性能的研究

    Institute of Scientific and Technical Information of China (English)

    安红萍; 李婷; 栗玉杰

    2015-01-01

    It is found that drawing by the new type of convex anvil can make the mechanical properties of work-piece better by comparing various mechanical properties of shafts after drawing by the new type of convex anvil and forg-ing by WHF method.%比较新型凸面砧拔长与WHF法锻造后轴类件的各项力学性能发现,采用新型凸面砧拔长能更好的改善工件力学性能。

  18. 行星齿轮精锻工艺分析与试验研究%Process analysis and experiment study on precision forging of planetary gear

    Institute of Scientific and Technical Information of China (English)

    闫红艳; 边翊; 彭冲; 刘桂华; 蒋智; 马晓晖

    2011-01-01

    According to indicator for gear accuracy testing, the questions that need pay attention to during accuracy controlling was put forward, and corresponding solution for each question was proposed. Based on systemic analysis of the problems such as elastic deformation of tooth profile, tooth surface and die life during the hot forging and cold forging process, the hot forging-cold finishing process was determined and the design of precision forging and hot forging dies were finished. The experiment study on the hot precision forging process for different blank dimensions and upsetting ratios was carried out, and the impact of blank and upsetting ratio to tooth file was analyzed. The result shows that, when billet diameter is less than the diameter at the small end of the gear and upset ratio is 1.5, the tooth profile and tooth head of the hot forging gear are filled well, and the tooth profile is full and accurate. After cleaning the iron oxide skin thoroughly, the surface quality of the forging is good.%根据齿轮精度检验的指标,提出了精度控制需要注意的问题,并针对每个问题提出解决办法.在系统分析热精锻和冷锻成形过程中齿形、齿面、弹性变形及模具寿命等问题的基础上,确定了热精锻—冷精整工艺流程,完成了精锻件及热精锻模的设计.对不同坯料尺寸和镦粗比的热精锻工艺过程进行了试验研究,分析了坯料和镦粗比对齿形充满的影响.研究结果表明,采用直径小于分锥角小端直径的坯料,选定镦粗比1.5进行热锻成形,锻造的热精锻齿轮齿形、齿顶充满效果较好,冷精整后的齿形饱满准确,在对氧化铁皮进行彻底清理后,锻件表面质量良好.

  19. 49 CFR 178.345-2 - Material and material thickness.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Material and material thickness. 178.345-2 Section 178.345-2 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SPECIFICATIONS FOR...

  20. Forging an identity: Four science doctoral students in a collaborative partnership with K--12 science teachers

    Science.gov (United States)

    Balinsky, Martin G.

    2006-12-01

    A primary conflict regarding the identity of science education is the competition between those emphasizing science aspects of science education versus those who emphasize the education. I examine a National Science Foundation funded program at "Southern State University" (pseudonym) known as the GK-12 Project that placed science doctoral students into K-12 classrooms, where they worked with practicing science teachers. My research question was: How do GK-12 Fellows forge an identity through their experiences as both teachers and doctoral students? I used the "hermeneutic dialectic circle", a process whereby I interviewed each stakeholder in turn, and conducted member checks. My primary sources were interviews, and my primary subjects were four Fellows. One of the Fellows, Jose, left the program after one year. The other three in my study, Wanda, Rebecca, and Nathan, remained for all three years. The starting point for their learning was admitting what they did not know. These three learned about science outside of their fields because they learned how to learn. They also took an interest in and enacted making connections to students. In negotiating two cultures, the Fellows achieved heightened awareness of the SSU science culture's current practices in college science teaching, particularly the problems. They noted the ineffectiveness of the didactic delivery style and the lack of formative assessment. These three Fellows manifested rational and pluralistic worldviews. Because of his frames that were derived from growing up under an authoritarian government in Cuba, Jose experienced the program differently than the other three Fellows. For Jose, his identity as a scientist and as an educator remained more static, as he identified more with the authoritarian outlook on education espoused in SSU's science departments. The science culture at SSU is centered in the authoritarian value structure sees a need for a "fixing" of education, to improve "poorly prepared

  1. 连杆锻模型槽设计及CAM%Design and CAM of Connecting Rod Forging Die

    Institute of Scientific and Technical Information of China (English)

    杨兆伟

    2011-01-01

    通过SolidWorks软件进行了连杆锻坯的建模,利用数值模拟结果指导完成了连杆锻模模具型槽的设计,确定了螺旋压力机的吨位.利用CAXAME软件的零件加工模块进行了工件的粗、精加工的设定,并且完成了刀具轨迹的加工模拟.利用软件的后置处理功能得到了NC代码,并使用高速加工技术完成了模具的高速切削加工.%The 3D modeling for connecting forging billet was set up by SolidWorks software.The design of cavity and flash groove of the forging die were completed based on the numerical simulation.The tonnage of spindle press was confirmed.The parameters for tools and cutting were set up by CAXAME software.The machining path for tooling was simulated.The NC code generated by software post-processer can be used to complete the high speed machining of mould.

  2. A Physically Based Dynamic Recrystallization Model Considering Orientation Effects for a Nitrogen Alloyed Ultralow Carbon Stainless Steel during Hot Forging

    Institute of Scientific and Technical Information of China (English)

    Gan-lin XIE; An HE; Hai-long ZHANG; Gen-qi WANG; Xi-tao WANG

    2016-01-01

    The nitrogen alloyed ultralow carbon stainless steel is a good candidate material for primary loop pipes of AP1000 nuclear power plant.These pipes are manufactured by hot forging,during which dynamic recrystallization acts as the most important microstructural evolution mechanism.A physically based model was proposed to describe and predict the microstructural evolution in the hot forging process of those pipes.In this model,the coupled effects of dislocation density change,dynamic recovery,dynamic recrystallization and grain orientation function were con-sidered.Besides,physically based simulation experiments were conducted on a Gleeble-3500 thermo-mechanical sim-ulator,and the specimens after deformation were observed by optical metallography (OM)and electron back-scat-tered diffraction (EBSD)method.The results confirm that dynamic recrystallization is easy to occur with increasing deformation temperature or strain rate.The grains become much finer after full dynamic recrystallization.The model shows a good agreement with experimental results obtained by OM and EBSD in terms of stress-strain curves,grain size,and recrystallization kinetics.Besides,this model obtains an acceptable accuracy and a wide applying scope for engineering calculation.

  3. Interface of components with large ratio of altitude to diameter formed by laminated pouring and accumulated liquid forging technology

    Institute of Scientific and Technical Information of China (English)

    姜巨福; 罗守靖; 王迎

    2003-01-01

    Based on the experiment of laminated pouring and accumulated liquid forging of 2A12 aluminum alloy,interface bonding of formed component with large altitude to dimeter ratio of altitude to diameter was investigated by means of SEM and Instron tensile tester.The results show that the method of laminated pouring and accumulated liquid forging can be used for forming components with large ratio.Pouring temperature,reheated temperature of die,pressure,pouring layers and standing time are all important technique parameters that influence the mechanical properties.When pouring temperature is 740℃,reheated temperature of die is 480℃,pressure is 500 kN,pouring layers are three and standing time is 5s,the mechanical properties of interface are the optimum ones,microstructure is equiaxed crystal and tensile fracture has character of dimple.There are three kinds of bonding,which are melting bonding,part melting bonding and mechanical bonding.And the interface of the melting bonding possesses the best mechanical properties.

  4. Waste Heat Recovery by Heat Pipe Air-Preheater to Energy Thrift from the Furnace in a Hot Forging Process

    Directory of Open Access Journals (Sweden)

    Lerchai Yodrak

    2010-01-01

    Full Text Available Problem statement: Currently, the heat pipe air-preheater has become importance equipment for energy recovery from industrial waste heat because of its low investment cost and high thermal conductivity. Approach: This purpose of the study was to design, construct and test the waste heat recovery by heat pipe air-preheater from the furnace in a hot brass forging process. The mathematical model was developed to predict heat transfer rate and applied to compute the heat pipe air-preheater in a hot brass forging process. The heat pipe air-preheater was designed, constructed and tested under medium temperature operating conditions with inlet hot gas ranging between 370-420°C using water as the working fluid with 50% filling by volume of evaporator length. Results: The experiment findings indicated that when the hot gas temperature increased, the heat transfer rate also increased. If the internal diameter increased, the heat transfer rate increased and when the tube arrangement changed from inline to staggered arrangement, the heat transfer rate increased. Conclusion/Recommendations: The heat pipe air-preheater can reduced the quantity of using gas in the furnace and achieve energy thrift effectively.

  5. Development of knowledge-based system for die forging process and tool design%基于知识的模锻工艺与模具设计系统开发

    Institute of Scientific and Technical Information of China (English)

    李世龙; 庄新村; 黄少东; 刘川林; 赵震; 陈军

    2012-01-01

    "Hot forging + machining" is an effective way to manufacture spiral bevel gear. The final product's performance depends on the quality of hot forging. The finite element software Deform-3D was used to simulate the hot forging process of spiral bevel driven gear blank. The metal flow law of forging process was studied. The results show that the stress and strain are great and the temperature is high in the ladder place because of the metal flows difficultly in the ladder place. The flow of metal can be better by improving die parameters. The relationship between initial forging temperature and forging energy consumption was studied. The results show that the forging energy consumption changes a little when the initial forging temperature is different The numerical simulation on forging technology can be applied to improve die patameters and forging process parameters.%模锻工艺与模具设计是一个经验积累和知识集成的过程.为实现优化设计的目标,利用知识工程的理论,综合开放性知识库、知识管理系统以及基于知识逻辑推理技术的支持,以Unigraphics NX为开发平台,采用混合开发模式,建立基于知识的模锻设计系统.从而有效地利用已有的知识和经验,提高设计过程的自动化程度和效率,扩展系统的应用范围与稳定性.

  6. Peripapillary choroidal thickness in healthy Turkish subjects

    Directory of Open Access Journals (Sweden)

    Erbagci H

    2015-07-01

    Full Text Available Hulya Erbagci,1 Burak Oren,2 Seydi Okumus,3 Serhat Kenan,3 Pelin Celemler,3 Ibrahim Erbagci3 1Department of Anatomy, Medical Faculty, Zirve University Emine Bahattin Nakiboglu, Gaziantep, 2Department of Ophthalmology, Kilis State Hospital, Kilis, 3Department of Ophthalmology, Faculty of Medicine, University of Gaziantep, Gaziantep, Turkey Aim: The objective of the study reported here was to investigate the normal peripapillary choroidal thickness (CT, measured by enhanced depth imaging optical coherence tomography (EDI-OCT, in healthy Turkish volunteers. Materials and methods: In this prospective cross-sectional study, 57 eyes of 57 healthy Turkish subjects were enrolled. Each participant underwent a comprehensive ophthalmic examination and peripapillary CT measurement using EDI-OCT. Results: The mean age of the 25 female and 32 male patients in the study was 30.9±10.6 years (range, 18–56 years. The mean peripapillary CT at the superior, inferior, nasal, and temporal sites was 225±57, 183±47, 220±57, and 233±59 µm, respectively. The inferior peripapillary CT value was significantly lower than the peripapillary CT values (P<0.001 for all, whereas no significant differences were found between the superior, nasal, and temporal peripapillary CT values. Conclusion: The findings of the study revealed that Turkish people had significantly lower peripapillary CT values in the inferior quadrant than in the superior, nasal, and temporal quadrants. Keywords: peripapillary choroidal thickness, enhanced depth imaging optical coherence tomography, EDI-OCT

  7. Accurate thickness measurement of graphene

    Science.gov (United States)

    Shearer, Cameron J.; Slattery, Ashley D.; Stapleton, Andrew J.; Shapter, Joseph G.; Gibson, Christopher T.

    2016-03-01

    Graphene has emerged as a material with a vast variety of applications. The electronic, optical and mechanical properties of graphene are strongly influenced by the number of layers present in a sample. As a result, the dimensional characterization of graphene films is crucial, especially with the continued development of new synthesis methods and applications. A number of techniques exist to determine the thickness of graphene films including optical contrast, Raman scattering and scanning probe microscopy techniques. Atomic force microscopy (AFM), in particular, is used extensively since it provides three-dimensional images that enable the measurement of the lateral dimensions of graphene films as well as the thickness, and by extension the number of layers present. However, in the literature AFM has proven to be inaccurate with a wide range of measured values for single layer graphene thickness reported (between 0.4 and 1.7 nm). This discrepancy has been attributed to tip-surface interactions, image feedback settings and surface chemistry. In this work, we use standard and carbon nanotube modified AFM probes and a relatively new AFM imaging mode known as PeakForce tapping mode to establish a protocol that will allow users to accurately determine the thickness of graphene films. In particular, the error in measuring the first layer is reduced from 0.1-1.3 nm to 0.1-0.3 nm. Furthermore, in the process we establish that the graphene-substrate adsorbate layer and imaging force, in particular the pressure the tip exerts on the surface, are crucial components in the accurate measurement of graphene using AFM. These findings can be applied to other 2D materials.

  8. Minimum thickness anterior porcelain restorations.

    Science.gov (United States)

    Radz, Gary M

    2011-04-01

    Porcelain laminate veneers (PLVs) provide the dentist and the patient with an opportunity to enhance the patient's smile in a minimally to virtually noninvasive manner. Today's PLV demonstrates excellent clinical performance and as materials and techniques have evolved, the PLV has become one of the most predictable, most esthetic, and least invasive modalities of treatment. This article explores the latest porcelain materials and their use in minimum thickness restoration.

  9. Accurate thickness measurement of graphene.

    Science.gov (United States)

    Shearer, Cameron J; Slattery, Ashley D; Stapleton, Andrew J; Shapter, Joseph G; Gibson, Christopher T

    2016-03-29

    Graphene has emerged as a material with a vast variety of applications. The electronic, optical and mechanical properties of graphene are strongly influenced by the number of layers present in a sample. As a result, the dimensional characterization of graphene films is crucial, especially with the continued development of new synthesis methods and applications. A number of techniques exist to determine the thickness of graphene films including optical contrast, Raman scattering and scanning probe microscopy techniques. Atomic force microscopy (AFM), in particular, is used extensively since it provides three-dimensional images that enable the measurement of the lateral dimensions of graphene films as well as the thickness, and by extension the number of layers present. However, in the literature AFM has proven to be inaccurate with a wide range of measured values for single layer graphene thickness reported (between 0.4 and 1.7 nm). This discrepancy has been attributed to tip-surface interactions, image feedback settings and surface chemistry. In this work, we use standard and carbon nanotube modified AFM probes and a relatively new AFM imaging mode known as PeakForce tapping mode to establish a protocol that will allow users to accurately determine the thickness of graphene films. In particular, the error in measuring the first layer is reduced from 0.1-1.3 nm to 0.1-0.3 nm. Furthermore, in the process we establish that the graphene-substrate adsorbate layer and imaging force, in particular the pressure the tip exerts on the surface, are crucial components in the accurate measurement of graphene using AFM. These findings can be applied to other 2D materials.

  10. Soliton models for thick branes

    Energy Technology Data Exchange (ETDEWEB)

    Peyravi, Marzieh [Ferdowsi University of Mashhad, Department of Physics, School of Sciences, Mashhad (Iran, Islamic Republic of); Riazi, Nematollah [Shahid Beheshti University, Physics Department, Tehran (Iran, Islamic Republic of); Lobo, Francisco S.N. [Faculdade de Ciencias da Universidade de Lisboa, Instituto de Astrofisica e Ciencias do Espaco, Lisbon (Portugal)

    2016-05-15

    In this work, we present new soliton solutions for thick branes in 4+1 dimensions. In particular, we consider brane models based on the sine-Gordon (SG), φ{sup 4} and φ{sup 6} scalar fields, which have broken Z{sub 2} symmetry in some cases and are responsible for supporting and stabilizing the thick branes. The origin of the symmetry breaking in these models resides in the fact that the modified scalar field potential may have non-degenerate vacua. These vacua determine the cosmological constant on both sides of the brane. We also study the geodesic equations along the fifth dimension, in order to explore the particle motion in the neighborhood of the brane. Furthermore, we examine the stability of the thick branes, by determining the sign of the w{sup 2} term in the expansion of the potential for the resulting Schroedinger-like equation, where w is the five-dimensional coordinate. It turns out that the φ{sup 4} brane is stable, while there are unstable modes for certain ranges of the model parameters in the SG and φ{sup 6} branes. (orig.)

  11. Finite Element Analysis of Width to Thickness Limitation in Racetrack Section Steel Transmission Pole Used Q460 High-strength Steel%Q460跑道型截面钢管杆宽厚比限值有限元分析

    Institute of Scientific and Technical Information of China (English)

    黎景辉; 邓洪洲

    2012-01-01

    A problem of choosing the rational width to thickness ratio is presented in this paper. The ultimate bearing capacities and failure modes of members with different width to thickness ratios can be got through the calculation and analysis by finite program. A rational width to thickness ratio is presented according to the analysis of calculation results and references, which provides a reference for application to the project.%本文提出Q460钢管杆跑道型截面合理宽厚比限值问题,利用有限元软件结合实际工程对不同宽厚比参数的构件进行非线性数值模拟,分别得到它们的极限承载力与相应破坏模式.通过结果分析并结合相关文献,提出供实际工程参考的合理宽厚比限值.

  12. Choroidal thickness in patients with diabetic retinopathy

    Directory of Open Access Journals (Sweden)

    Ünsal E

    2014-03-01

    Full Text Available Erkan Ünsal, Kadir Eltutar, Sibel Zirtiloğlu, Nurhan Dinçer, Sezin Özdoğan Erkul, Hülya GüngelDepartment of Ophthalmology, Istanbul Education and Research Hospital, Istanbul, TurkeyPurpose: The aim of the study reported here was to assess choroidal thickness (CT and central macular thickness (CMT in patients with diabetic retinopathy.Materials and methods: A total of 151 eyes from 80 patients from the retina department of Istanbul Training and Research Hospital who had type 2 diabetes mellitus with diabetic retinopathy were studied retrospectively in this cross-sectional research. Patients were divided into three groups: mild–moderate nonproliferative diabetic retinopathy without macular edema (NPDR, mild–moderate nonproliferative diabetic retinopathy with macular edema (DME, and proliferative diabetic retinopathy (PDR. In addition, 40 eyes of 20 healthy individuals comprised a control group. Choroidal thickness was measured from the posterior edge of the retinal pigment epithelium to the choroid/sclera junction at 500-µm intervals up to 1,500 µm temporal and nasal to the fovea. The CMT measurement was obtained for each eye. Serum hemoglobin A1c (HbA1c levels were measured.Results: The study included 191 eyes, comprising 151 eyes of 80 patients and 40 eyes of 20 healthy individuals. Of the 151 patient eyes, 61 had NPDR, 62 had PDR, and 28 eyes had DME. There was no statistically significant difference in age between the groups (P>0.05. In both the PDR and DME groups, the CT was statistically significantly decreased compared with the control group (P<0.001, P<0.001 for the PDR and DME groups, respectively. The mean CMT in the DME group was increased significantly compared with both the NPDR and PDR groups (P<0.001, P<0.001, respectively. In all three groups, serum HbA1c levels were found to be increased significantly compared with the control group (P=0.000. We found a statistically weak–moderate negative correlation between

  13. Friction welding of a nickel free high nitrogen steel: influence of forge force on microstructure, mechanical properties and pitting corrosion resistance

    Directory of Open Access Journals (Sweden)

    Mrityunjoy Hazra

    2014-01-01

    Full Text Available In the present work, nickel free high nitrogen austenitic stainless steel specimens were joined by continuous drive friction welding process by varying the amount of forge (upsetting force and keeping other friction welding parameters such as friction force, burn-off, upset time and speed of rotation as constant at appropriate levels. The joint characterization studies include microstructural examination and evaluation of mechanical (micro-hardness, impact toughness and tensile and pitting corrosion behaviour. The integrity of the joint, as determined by the optical microscopy was very high and no crack and area of incomplete bonding were observed. Welds exhibited poor Charpy impact toughness than the parent material. Toughness for friction weld specimens decreased with increase in forge force. The tensile properties of all the welds were almost the same (irrespective of the value of the applied forge force and inferior to those of the parent material. The joints failed in the weld region for all the weld specimens. Weldments exhibited lower pitting corrosion resistance than the parent material and the corrosion resistance of the weld specimens was found to decrease with increase in forge force.

  14. Development and outlook of free forging hydraulic press%自由锻造液压机的发展与展望

    Institute of Scientific and Technical Information of China (English)

    郭晓锋; 成先飚; 张建华

    2012-01-01

    回顾了自由锻造液压机的发展历程,详细介绍各发展阶段自由锻造液压机的类型和技术特点.比较液压油和纯水两种压机工作介质的理化特性,分析了纯水自由锻造液压机的技术优势,为自由锻造液压机的发展提供了研究方向.%The development course of the free forging hydraulic press is reviewed in the paper. The type and technical features of the free forging hydraulic press in various development stages are introduced in details. The technical advantages of pure water free forging press are systematically analyzed based on' comparison of the chemical and physical properties of two working substances ( pure water and hydraulic oil). The research directions for development of the free forging hydraulic press are recommended.

  15. Forging of cast Mg-3Sn-2Ca-0.4Al-0.4Si magnesium alloy using processing map

    Energy Technology Data Exchange (ETDEWEB)

    Rao, K. P.; Suresh, K.; Prasad, Y. V. R. K. [University of Hong Kong, Hong Kong (China); Hort, N.; Kainer, K. U. [Magnesium Innovation Centre, Geesthacht (Germany)

    2016-06-15

    Mg-3Sn-2Ca (TX32) alloy has good creep resistance but limited workability. Minor amounts of Al and Si have been added to TX32 for improving its hot workability. The processing map for the TX32-0.4Al-0.4Si alloy exhibited two workability domains in the temperature and strain rate ranges: (1) 310-415.deg.C/0.0003-0.003 s-1 and (2) 430-500.deg.C/0.003-3 s-1. The alloy exhibited flow instability at temperatures < 350.deg.C at strain rates > 0.01 s-1. The alloy has been forged to produce a cup shape component to validate these findings of processing map. Finite-element (FE) simulation has been performed for obtaining the local variations of strain and strain rate within the forging. The microstructures of the forged components under the optimal domain conditions revealed dynamically recrystallized grains, and those forged in the flow instability regime have fractured and exhibited flow localization bands and cracks. The experimental load stroke curves correlated well with those obtained by FE simulation.

  16. A Comparative Study on Wear Properties of As Cast, Cast Aged and Forge Aged A356 Alloy with Addition of Grain Refiner and/or Modifier

    Directory of Open Access Journals (Sweden)

    D.G. Mallapur

    2015-03-01

    Full Text Available In the present work, a comparative wear behavior study of three categories of materials viz, as cast, cast aged (casting followed by T6 and forge aged (forging followed by T6 has been investigated. Neither melt treatment nor solid state processing (like aging and forging seems to be altering the wear behavior of the materials drastically. Cast aged A356 materials exhibit higher wear resistance compared to as cast and forge aged A356 materials. Further, it was observed that cast aged samples register lower coefficient of friction compared to other samples. It is also noted that the difference in wear behavior is revealed only at conditions of higher load, higher speed and longer sliding distance of testing. At lower regimes the difference is marginal. Among cast aged samples, ones treated with combined addition exhibit better wear resistance compared to other materials. Samples treated with combined addition register lowest coefficient of friction followed by samples treated with Sr, those with B, those with Ti and untreated ones. Abrasive wear mechanism is found to be operative in the regime of higher loading and higher velocity of sliding. Adhesive wear mechanism seems to be dominating the wear process at the lower regime of load and velocity of sliding.

  17. Liquid film thickness measurement by two-line TDLAS

    Science.gov (United States)

    Yang, Huinan; Chen, Jun; Cai, Xiaoshu; Greszik, Daniel; Dreier, Thomas; Schulz, Christof

    2014-04-01

    A fiber-based two-line tunable diode-laser absorption sensor with two near-infrared (NIR) distributed-feedback (DFB) diode lasers at ˜1.4 μm was used for non-intrusive time-resolved liquid water film thickness measurement. When probing the liquid film at two different wavelengths with significantly different absorption cross-sections, the additional signal losses due to surface fowling, reflection and beam steering can be eliminated. In this work, the evaporation process of a liquid film on transparent quartz plate was tracked and large fluctuations of film thickness were found at the end of the evaporation.

  18. Liquid film thickness measurement by two-line TDLAS

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Huinan [School of Energy and Power Engineering, University of Shanghai for Science and Technology, 200093, Shanghai, China and IVG, University of Duisburg-Essen, 47057, Duisburg (Germany); Chen, Jun; Cai, Xiaoshu [School of Energy and Power Engineering, University of Shanghai for Science and Technology, 200093, Shanghai (China); Greszik, Daniel; Dreier, Thomas; Schulz, Christof [IVG, University of Duisburg-Essen, 47057, Duisburg (Germany)

    2014-04-11

    A fiber-based two-line tunable diode-laser absorption sensor with two near-infrared (NIR) distributed-feedback (DFB) diode lasers at ∼1.4 μm was used for non-intrusive time-resolved liquid water film thickness measurement. When probing the liquid film at two different wavelengths with significantly different absorption cross-sections, the additional signal losses due to surface fowling, reflection and beam steering can be eliminated. In this work, the evaporation process of a liquid film on transparent quartz plate was tracked and large fluctuations of film thickness were found at the end of the evaporation.

  19. Self-assembled film thickness determination by focused ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Dejeu, J. [Institut UTINAM, UMR 6213 CNRS-UFC - equipe Materiaux et Surfaces Structures, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France)], E-mail: jerome.dejeu@univ-fcomte.fr; Salut, R. [Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Centrale MIMENTO, Universite de Franche-Comte, 32 avenue de l' Observatoire - 25044 Besancon Cedex (France); Spajer, M. [Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Centrale MIMENTO, Universite de Franche-Comte, 32 avenue de l' Observatoire - 25044 Besancon Cedex (France); Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Departement d' Optique, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France); Membrey, F.; Foissy, A. [Institut UTINAM, UMR 6213 CNRS-UFC - equipe Materiaux et Surfaces Structures, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France); Charraut, D. [Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Departement d' Optique, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France)

    2008-06-30

    The thickness evolution of multilayer film is investigated by focused ion beam (FIB) in the domain of polymer multilayers. This method, currently used in the modification and the characterization of integrated circuits, proves it is possible to determine the polymer film thickness. Sample cutting and its observation of the cross-section are performed in the FIB without leaving the vacuum chamber. Two main conclusions can be drawn: (1) the roughness of the film increases with the number of layer deposit, (2) the film growth changes from nonlinear (called exponential) to linear beyond 300 nm (70 layers)

  20. Deformation behavior of A6063 tube with initial thickness deviation in free hydraulic bulging

    Institute of Scientific and Technical Information of China (English)

    YANG Lian-fa; GUO Cheng; DENG Yang

    2006-01-01

    Experiment on seamless tubes of aluminum alloy A6063 with initial thickness deviation of 0-20% was conducted through a free hydraulic bulging with tube ends free. The influence of initial thickness deviation on the cross-section profile, thickness distribution, maximum internal pressure and maximum radial expansion was investigated. FEM simulation was also performed in order to examine and help explaining the experimental results. The results indicate that the internal pressure and maximum internal pressure appear to be little influenced by the initial thickness deviation, and that the cross-section profile of the bulged tube changes diversely and can not be a perfect circle. The results also suggest that the increase in initial thickness deviation may lead to a remarkable decrease in maximum radial expansion, and a rapid increase in thickness deviation and the center eccentricity of the inner and outer profiles.