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Sample records for roll mill grinding

  1. The implementation of HPGR mills in existing grinding circuits

    Energy Technology Data Exchange (ETDEWEB)

    Patzelt, N.; Knecht, J.; Longhurst, D. [Krupp Polysius AG, Beckum (Germany)

    1996-12-31

    High pressure grinding mills have been successfully introduced in the industry. They offer the possibilities for capacity increase of existing plants and reduction of operating costs. The plants in operation are running in different applications and modes of operation. They can be installed in a combination with SAG and ball mills or in a stand-alone mode. In combination with other grinding mills, it has to be investigated how the HPGR can be installed to reach the full efficiency. This paper describes the possibilities of implementing high pressure grinding rolls and shows by case studies the potential of savings which could be reached.

  2. Cost optimization of stirred ball mill grinding

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, C.W.; Mehta, R.K. [Alabama Univ., University, AL (United States). Mineral Resources Inst.

    1991-12-31

    On going research at the University of Alabama has shown that stirred ball mill grinding is the highest cost unit operation in the beneficiation of Eastern Oil Shales. Minimization of that cost is critical if oils derived by beneficiation and hydroretorting of Eastern shales are to become an economic alternative to conventional crude oils. Cost optimization of stirred ball milling is a substantially different problem than optimizing a conventional (tumbling) mill operation. For conventional mills minimum cost is virtually synonymous with minimum energy consumption. Because the technology is mature and well understood, the operator can predictably optimize within a very narrow range of operating conditions. In contrast, stirred ball milling offers the operator several more ``degrees of freedom`` in selecting operating conditions. An example is the selection of rotor speed. In general, lower speeds result in lower energy consumption per ton of material ground but at the cost of reduced mill capacity per unit volume. Because stirred ball mills have a high capital cost per unit volume the trade off between energy consumption and capacity becomes critical. This paper presents a generalized total cost mode for stirred ball milling and examines data generated in the grinding of oil shales in terms of the model. The paper also discuss the role of the cost model in guiding future research in grinding circuit optimization.

  3. Cost optimization of stirred ball mill grinding

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, C.W.; Mehta, R.K. (Alabama Univ., University, AL (United States). Mineral Resources Inst.)

    1991-01-01

    On going research at the University of Alabama has shown that stirred ball mill grinding is the highest cost unit operation in the beneficiation of Eastern Oil Shales. Minimization of that cost is critical if oils derived by beneficiation and hydroretorting of Eastern shales are to become an economic alternative to conventional crude oils. Cost optimization of stirred ball milling is a substantially different problem than optimizing a conventional (tumbling) mill operation. For conventional mills minimum cost is virtually synonymous with minimum energy consumption. Because the technology is mature and well understood, the operator can predictably optimize within a very narrow range of operating conditions. In contrast, stirred ball milling offers the operator several more degrees of freedom'' in selecting operating conditions. An example is the selection of rotor speed. In general, lower speeds result in lower energy consumption per ton of material ground but at the cost of reduced mill capacity per unit volume. Because stirred ball mills have a high capital cost per unit volume the trade off between energy consumption and capacity becomes critical. This paper presents a generalized total cost mode for stirred ball milling and examines data generated in the grinding of oil shales in terms of the model. The paper also discuss the role of the cost model in guiding future research in grinding circuit optimization.

  4. Continuous grinding mill simulation using Austin's model

    Directory of Open Access Journals (Sweden)

    Andr\\u00E9 Carlos Silva

    2012-01-01

    Full Text Available Comminution is a frequently-required step in mineral processing and is responsible for almost 90% of all energy consumption in a mineral processing plant. Tumbling mill design has been studied since the middle of the XIX century. There are many comminution models in the literature, with preponderance, however, of Austin’s model (2002 for mineral impact breakage. In this paper, Austin’s model was applied to tubular tumbling mills. Once Austin's model was proposed for batch processing of narrowly-distributed fraction sizes, an artifice has allowed it to be used in continuous grinding mill processes with widely-distributed fraction sizes. Interesting results were obtained with errors less than 0.005 for mills with sharp residence time distributions.

  5. Residence time distribution in a vibrating grinding mill

    International Nuclear Information System (INIS)

    In order to determine the values that are characteristic of the continuous conveying process within a vibration grinding mill measurements of the residence time by radioactive marking using Au-198 have been carried out. For evaluating the results the dispersion model was made use of. When grinding an organic product in a Palla-50-U-vibration mill, with or without retaining weir, the volumetric grinding stock filling ratio was found to range between 30 and 35 per cent for the different test runs. The calculated dispersion coefficients range between 200 and 300 cm2/min and are proportional to the axial velocity of transport. (orig.)

  6. High pressure grinding rolls (HPGR) applications in the cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Aydogan, N.A.; Ergun, L.; Benzer, H. [Hacettepe University, Ankara (Turkey). Mining Engineering Dept.

    2006-02-15

    In this study, the performance evaluation studies in five cement grinding circuits, in which HPGR is used in various configurations, were presented. Sampling surveys were performed around the circuits followed by the determination of the size distribution of the samples down to 1.8 {mu}m using a combination of sieving and laser sizing methods. The results showed that the specific energy consumption of the circuit decreases as the size reduction achieved by the HPGR increases. As given in the case studies when the size reduction ratio (F{sub 80}/P{sub 80}) changed from 308.2 to 4.4, the specific energy consumption of the HPGR was 8.02 and 4.05 kWh/ton, respectively. Since various configurations offer rather different ball mill feeds, the best usage of HPGR could be attained by optimization of operating parameters of both ball mills and air classifiers. (author)

  7. Evaluation of Recycle Grinding Performance in Flour Milling

    Science.gov (United States)

    Mazlina Mustapa Kamal, Siti; Webb, Colin

    A typical flour milling process is a very linear operation that is almost entirely void of recycled streams where separate fractions from each operation go ahead as new streams to the next operation. In some cases, there are opportunities for combining some streams, for recycling particles that have been insufficiently broken to go back to the same roller mill. This study introduces this recycle concept in flour milling process at second break system. The recycle grinding assessment was made using a Satake STR-100 test roller mill. The recycle process was started after the second break system and the number of recycle grinding was up to 7 regrinds. The particle size distribution and ash analysis were produced to describe the behaviour of the recycle grinding performance. The material release was sifted on a range of sieves and the ash content was analysed using a laboratory furnace. The performance for each recycle stage was investigated. It was determined that it is possible for some coarse particles that contain only bran to keep being recycled in the recycle circuit. A purging operation was recommended to be included in the recycle system, to separate the unwanted particles.

  8. Research on roll wear of 2050mm hot strip finishing train (CVC Mill) of Baosteel

    International Nuclear Information System (INIS)

    In this paper, the general characteristics and affecting factors of work and backup rolls wear of finishing train were analyzed. Taking the CVC finishing mills of 2050mm hot strip mill of Baosteel as an example, the roll wear magnitude and contour were calculated in theory, and measured by the present grinding machine in experiment. The calculated results agree well with the measured data in distribution, and also in general characteristics. Based on the calculated and measured results, an on-line prediction model by which the roll wear distribution characteristics of a CVC mill can be revealed more accurately was proposed. (author)

  9. Fine grinding of brittle minerals and materials by jet mill

    Directory of Open Access Journals (Sweden)

    Lek Sikong

    2008-05-01

    Full Text Available Various variables affecting grinding, such as air pressure, minerals or materials hardness, feed size were investigated.The limitations of grinding of gypsum, barite, ilmenite, quartz and ferrosilicon were also elucidated by means of particlefineness size distribution and morphology of ground products. It was found that:1 The density of particles, which are in the grinding zone affects the product fineness, i.e. higher feed rate resultsin a larger product size. The appropriate feed rate is suggested to be 0.2~0.5 g/s. Moreover, the density and hardness ofminerals or materials tend to have an effect on the product fineness. Heavy minerals, such as barite or ilmenite, exhibit afiner product size than lighter minerals, like quartz. However, for quartz, the higher hardness also results in a larger d50.2 Air pressure is the most vital variable which affects the grinding by a jet mill. The d50 seems to relate to theapplied air pressure as a power law equation expressed as following:d50 = aP b ; as P 0The a-value and b-value have been found to correlate to the feed size. The higher the air pressure applied the finerthe product size attained. Moreover, air pressure has a greater effect on hard minerals than on softer ones.3 Feed size seems to have a small effect on ground the product fineness of soft materials, such as gypsum andbarite, but a significant effect on that of hard materials, such as ferrosilicon and quartz, in particularly by milling at low airpressures of 2~3 kg/cm2.4 For the breakage behavior and morphology of ground materials, it was also found that the minerals having cleavages,such as gypsum and barite, tend to be broken along their cleavage planes. Thus, the particle size distribution of theseproducts becomes narrower. While quartz, ilmenite, and ferrosilicon have shattering and chipping breakage mechanisms,grinding results in angular shapes of the ground products and a wider size distribution. Blocks or platelets and agglomerationsmay occur during grinding of soft minerals, like gypsum, especially at lower and higher air pressures, respectively.

  10. The effect of grinding media performance on milling and operational behaviour

    Scientific Electronic Library Online (English)

    U., Weber; D., Langlois.

    2010-03-01

    Full Text Available The effect of grinding media performance on milling and operational behaviour was demonstrated under different selected conditions of calcium carbonate slurry milling. A variety of grinding media materials and bead sizes, along with two different stirrer tip speeds, were used in the grinding process [...] to generate a particle size reduction of the calcium carbonate (CaCO3). To determine the optimum milling parameters the collected test data were used to calculate and evaluate specific energy as well as stress intensity under different milling conditions.

  11. Relationships between resistance characteristics of barley kernels and energy consumption during grinding on hammer mill

    OpenAIRE

    Łysiak G.; Laskowski J.

    1997-01-01

    The present study undertakes evaluation of the influence of dimensional and resistance characteristics of barley kernels on the energy consumption during grinding. Resistance characteristics of barley kernels was determined using the uniaxial compression test carried out on an universal Instron tester. Studies on the grinding process were conducted with the use of a hammer mill. Study results were presented in the form of regression equations.

  12. Investigation of the milling capabilities of the F10 Fine Grind mill using Box-Behnken designs.

    Science.gov (United States)

    Tan, Bernice Mei Jin; Tay, Justin Yong Soon; Wong, Poh Mun; Chan, Lai Wah; Heng, Paul Wan Sia

    2015-01-01

    Size reduction or milling of the active is often the first processing step in the design of a dosage form. The ability of a mill to convert coarse crystals into the target size and size distribution efficiently is highly desirable as the quality of the final pharmaceutical product after processing is often still dependent on the dimensional attributes of its component constituents. The F10 Fine Grind mill is a mechanical impact mill designed to produce unimodal mid-size particles by utilizing a single-pass two-stage size reduction process for fine grinding of raw materials needed in secondary processing. Box-Behnken designs were used to investigate the effects of various mill variables (impeller, blower and feeder speeds and screen aperture size) on the milling of coarse crystals. Response variables included the particle size parameters (D10, D50 and D90), span and milling rate. Milled particles in the size range of 5-200 ?m, with D50 ranging from 15 to 60 ?m, were produced. The impeller and feeder speeds were the most critical factors influencing the particle size and milling rate, respectively. Size distributions of milled particles were better described by their goodness-of-fit to a log-normal distribution (i.e. unimodality) rather than span. Milled particles with symmetrical unimodal distributions were obtained when the screen aperture size was close to the median diameter of coarse particles employed. The capacity for high throughput milling of particles to a mid-size range, which is intermediate between conventional mechanical impact mills and air jet mills, was demonstrated in the F10 mill. Prediction models from the Box-Behnken designs will aid in providing a better guide to the milling process and milled product characteristics. PMID:25497486

  13. Fine grinding of coal with a stirred ball mill; Baitai kakuhan mill ni yoru sekitan no bifunsai

    Energy Technology Data Exchange (ETDEWEB)

    Hirajima, T.; Tsunekawa, M.; Yoneda, T. [Hokkaido University, Sapporo (Japan). Faculty of Engineering

    1997-08-25

    In production of super-clean coal by any physical coal-cleaning process, the feed coal must be micronized to liberate finely disseminated mineral matter. One of the most efficient devices for micronizing coal is a stirred ball mill. Using the laboratory mill with a relatively high media loading (80 % filling), small grinding media (less than 1 mm diameter), and three coals, effects of some parameters such as media size, stirring speed, and pulp density on the grinding of coals have been studied. The product with a median size of 2{mu}m was obtained at a suitable operating conditions with a mean residence time of 6 min. The wear loss of the grinding media and vessel depended strongly on the amount of the hard minerals disseminated in coal, such as quartz, pyrite and iron oxide. 12 refs., 13 figs., 5 tabs.

  14. Grinding and cooking dry-mill germ to optimize aqueous enzymatic oil extraction

    Science.gov (United States)

    The many recent dry grind plants that convert corn to ethanol are potential sources of substantial amounts of corn oil. This report describes an aqueous enzymatic extraction (AEE) method to separate oil from dry-mill corn germ (DMG). The method is an extension of AEE previously developed for wet...

  15. Study on ultra-fine grinding method by mechanical force (2nd report). Development of stirred suspension mill and study of its fine grinding mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Okuda, Satoshi

    1988-03-01

    Possibility of ultra-fine grinding with a stirred suspension mill in place of stirred ball mill, and the relationship between flowing pattern of particles in a chamber and grindablity were examined. The stirred suspension mill in which fed raw particles are suspended and mixed by stirring was developed and fine grinding experiment was carried out using limestone as a sample under different stirring and grinding conditions. Following parameters were used for this experiments: batch or semibatch operation; grinding period; rotating velocity of propeller type mixing wing; sample particle size; sample concentration; position of wing(wing height). The total amount and size distribution of prepared fine particles were examined and the flow pattern of particles in the grinding chamber was observed. The experimental results indicated that this mill could prepare the ultra-fine product; that semi-batch system was better than the batch system and that the most important parameter was flow pattern of particles in the grinding chamber. (10 figs, 2 refs)

  16. Application of multi regressive linear model and neural network for wear prediction of grinding mill liners

    Directory of Open Access Journals (Sweden)

    Farzaneh Ahmadzadeh

    2013-06-01

    Full Text Available The liner of an ore grinding mill is a critical component in the grinding process, necessary for both high metal recovery and shell protection. From an economic point of view, it is important to keep mill liners in operation as long as possible, minimising the downtime for maintenance or repair. Therefore, predicting their wear is crucial. This paper tests different methods of predicting wear in the context of remaining height and remaining life of the liners. The key concern is to make decisions on replacement and maintenance without stopping the mill for extra inspection as this leads to financial savings. The paper applies linear multiple regression and artificial neural networks (ANN techniques to determine the most suitable methodology for predicting wear. The advantages of the ANN model over the traditional approach of multiple regression analysis include its high accuracy.

  17. Effect of operating parameters in stirred ball mill grinding of coal

    Energy Technology Data Exchange (ETDEWEB)

    Mankosa, M.J.; Adel, G.T.; Yoon, R.H. (Virginia Polytechnic Inst. and State Univ., Blacksburg (USA). Dept. of Mining and Minerals Engineering)

    1989-12-01

    For any physical separation process to work efficiently, a high degree of liberation must first be achieved. In the case of coal, a mean particle size as fine as 5 mum may be necessary when deep cleaning is required. One of the most energy-efficient devices for producing micronized coal is the stirred ball mill. In the present work, various operating parameters such as stirring speed, pulp density and the use of grinding aids have been studied using a laboratory stirred ball mill. It has been found that the mill operates most efficiently at low stirring speeds and high pulp densities, as long as the viscosity is controlled within limits. The use of grinding aids reduced the energy consumption significantly, which may be attributed to a reduction in slurry viscosity. (orig.).

  18. ALSTOM Schusselmuhle fur die feinvermahlung von anhydrit ALSTOM bowl mill for anhydrite fine grinding

    CERN Document Server

    Angleys, M

    2003-01-01

    After the ALSTOM bowl mill had proved a success during numerous laboratory tests using different industrial minerals, for the first time a mill, type SM 20/12 was commissioned for ATLAS s.c. at Lodz /Poland for anhydrite grinding. Based on corresponding laboratory tests with anhydrite, it was possible to adapt the equipment to the requirements of the material with modified properties. Due to the project preparation together with the customer, the mill could be installed and commissioned according to schedule by a joint team of engineers for erection and commissioning.

  19. Analysis of roll stack deflection in a hot strip mill

    Scientific Electronic Library Online (English)

    Sudipta, Sikdar; Shylu, John; Ashwin, Pandit; Raju, Dasu.

    2007-09-01

    Full Text Available Predictive models are required to provide the bending set point for bending for the flatness control devices at rolling stands of finishing mill of Hot Strip Mill (HSM). A simple model for roll stack deflection at the finishing mill has been illustrated where a modified Misaka’s equation has been us [...] ed to obtain mean flow-stress. Investigation has been performed to understand the effect of width of roll on roll stack deflection. The bending on the deflection has been found to have a positive effect to reduce the amount of the stack deflection. The results from the sensitivity analysis of the roll width on roll deflection are also described.

  20. Investigation of unbalanced mass of a work roll in a cold rolling mill

    International Nuclear Information System (INIS)

    An abrasion due to continuous friction between a work roll and strip causes the mass of the work roll to be unbalanced in the rolling process. We developed a mathematical model for the rolling mill considering the unbalanced mass and verified the model experimentally. The work roll was approximated as a rigid rotor with eccentricity, and the effect of the unbalanced mass on chatter vibration was investigated. The joint forces computed by quasistatic analysis were applied to the work roll in the rolling mill. Transient responses were obtained, and frequency analysis was performed by solving equations of motion using a direct integration method. Horizontal vibrations were more strongly affected by eccentricity than vertical vibrations. In the horizontal direction, a small eccentricity of 1% of the work roll radius considerably increased the amplitude of the chatter frequency

  1. Particle Characterisation and Grinding Behaviour of Gamma-Alumina Slurries Prepared in a Stirred Media Mill

    OpenAIRE

    Stephen Adegbite

    2012-01-01

    This paper investigates gamma-alumina slurry preparation in a stirred media mill to develop protocols for the characterisation of slurries for coating onto monolithic catalyst supports. The relationship between the pH and the zeta potential of particles is determined. The gamma–alumina particles are found to be optimally stabilised at a pH of 4 and zeta potential of +41 mV. The grinding behaviour of gamma-alumina particles inside the mill is determined in terms of the number of stress events...

  2. Effect of media size in stirred ball mill grinding of coal

    Energy Technology Data Exchange (ETDEWEB)

    Mankosa, M.J.; Adel, G.T.; Yoon, R.H.

    1986-12-01

    As a prerequisite to producing super-clean coal with any physical coal-cleaning process, such as microbubble flotation, the feed coal must be micronized to liberate finely disseminated mineral matter. The stirred ball mill is regarded as one of the most efficient devices for micronizing coal. Using a 13.4 cm batch mill, the optimum operating conditions have been determined in terms of media size, feed size and media type. The rate of breakage determined with monosized feeds are compared on the basis of specific energy consumption. It has been found that a 20:1 ball size/particle size ratio gives optimum grinding conditions.

  3. Particle Characterisation and Grinding Behaviour of Gamma-Alumina Slurries Prepared in a Stirred Media Mill

    Directory of Open Access Journals (Sweden)

    Stephen Adegbite

    2012-10-01

    Full Text Available This paper investigates gamma-alumina slurry preparation in a stirred media mill to develop protocols for the characterisation of slurries for coating onto monolithic catalyst supports. The relationship between the pH and the zeta potential of particles is determined. The gamma–alumina particles are found to be optimally stabilised at a pH of 4 and zeta potential of +41 mV. The grinding behaviour of gamma-alumina particles inside the mill is determined in terms of the number of stress events (SN, stress energy (SE and the specific energy (Em,p. The visualisation of the particles at different stages of milling is done by scanning electron microscope (SEM. The results show that finer particles are produced by increasing milling duration from 0 – 240 min due to an increase in SN and that the use of smaller grinding media inside the mill produced finer particles due to an efficient consumption of Em,p.

  4. Aplicação de prensas de rolos em minério de ferro High pressure grinding rolls for iron ore

    Directory of Open Access Journals (Sweden)

    Farley Santos Ribeiro

    2010-06-01

    Full Text Available O Projeto Minas-Rio, de propriedade da Anglo Ferrous Brazil, prevê a utilização de prensa de rolos para cominuição do undersize do peneiramento (-25,4 mm. Esta é uma aplicação que se torna cada dia mais comum, porém relativamente nova em minério de ferro. Foram realizados estudos no Centro de Pesquisa da Krupp/Polysius na Alemanha, com o objetivo de validar a aplicação de prensa de rolos para minério de ferro, de determinar os principais parâmetros usados no dimensionamento e de avaliar o impacto do aumento da umidade da alimentação na capacidade específica e na distribuição granulométrica do produto. Os excelentes resultados obtidos, nos ensaios em escala-piloto, somados aos ganhos financeiros da aquisição e operação, à maior estabilidade do processo diante variações de w i (work index e à distribuição granulométrica da alimentação, contribuíram para aprovar, de forma irrestrita, a aplicação de prensa de rolos para cominuição de minério de ferro no Projeto Minas-Rio.The Minas-Rio Project that is being implemented by Anglo Ferrous Brazil, foresees the use of HPGR (High Pressure Grinding Rolls to grind the undersize from screening at (-25.4 mm. This application is recent for iron ore comminuting. The study described herein, took place at the Krupp/Polysius Research Center, in Germany, aiming to validate the HPGR application for iron ore, as well as to determine the main parameters used in equipment sizing. The study also aimed to assesses the impact of moisture variation on ore feed in respect to specific grinding capacity and product size distribution. The great results obtained from the sample tests that demonstrated more process stability for the work index (w i and granulometric feed distribution variations, together with the possible financial gains from the HPGR implementation, contributed to the unrestricted approval of the HPGR application for iron ore comminuting in the Minas-Rio Project.

  5. Aplicação de prensas de rolos em minério de ferro / High pressure grinding rolls for iron ore

    Scientific Electronic Library Online (English)

    Farley Santos, Ribeiro; José Francisco Cabello, Russo; Thiago, Costa.

    2010-06-01

    Full Text Available O Projeto Minas-Rio, de propriedade da Anglo Ferrous Brazil, prevê a utilização de prensa de rolos para cominuição do undersize do peneiramento (-25,4 mm). Esta é uma aplicação que se torna cada dia mais comum, porém relativamente nova em minério de ferro. Foram realizados estudos no Centro de Pesqu [...] isa da Krupp/Polysius na Alemanha, com o objetivo de validar a aplicação de prensa de rolos para minério de ferro, de determinar os principais parâmetros usados no dimensionamento e de avaliar o impacto do aumento da umidade da alimentação na capacidade específica e na distribuição granulométrica do produto. Os excelentes resultados obtidos, nos ensaios em escala-piloto, somados aos ganhos financeiros da aquisição e operação, à maior estabilidade do processo diante variações de w i (work index) e à distribuição granulométrica da alimentação, contribuíram para aprovar, de forma irrestrita, a aplicação de prensa de rolos para cominuição de minério de ferro no Projeto Minas-Rio. Abstract in english The Minas-Rio Project that is being implemented by Anglo Ferrous Brazil, foresees the use of HPGR (High Pressure Grinding Rolls) to grind the undersize from screening at (-25.4 mm). This application is recent for iron ore comminuting. The study described herein, took place at the Krupp/Polysius Rese [...] arch Center, in Germany, aiming to validate the HPGR application for iron ore, as well as to determine the main parameters used in equipment sizing. The study also aimed to assesses the impact of moisture variation on ore feed in respect to specific grinding capacity and product size distribution. The great results obtained from the sample tests that demonstrated more process stability for the work index (w i) and granulometric feed distribution variations, together with the possible financial gains from the HPGR implementation, contributed to the unrestricted approval of the HPGR application for iron ore comminuting in the Minas-Rio Project.

  6. The investigation of grinding kinetics of power plant solid fossil fuel in ball mill

    Energy Technology Data Exchange (ETDEWEB)

    S. Samanli; D. Cuhadaroglu; H. Ipek; Y. Ucbas [Zonguldak Karaelmas University, Zonguldak (Turkey). Mining Engineering Department

    2010-03-15

    The kinetics of batch dry grinding of power plant solid fossil fuel, from the feeds of sieve sizes -3.350 + 2.360, -2.360 + 1.700, -1.180 + 0.850, -0.425 + 0.300 and -0.212 + 0.150 mm have been determined using a Bond ball mill with a mixture of five ball sizes. The mill used has a diameter of 30.5 cm, length of 30.5 cm, providing a total mill volume of 22.272 cm{sup 3} with a total mass of 20.125 g steel ball mixtures of 38.10, 31.75, 25.40, 19.05 and 12.70 mm diameters. The balls occupied 22% of mill volume. The speed of rotation of the mill was chosen as 70 rpm. The specific rates of breakage (Si) and primary breakage distribution (B{sub i,j}) values, called as grinding breakage parameters, were determined for those feed size fractions to simulate the product size distributions for comparison to the experimentally obtained data. As the feed sizes increase, the Si values also increase, that is, faster breakage values from higher to lower values were in the order of solid fossil fuel by comparing to its {alpha} values. Breakage distribution functions were found non-normalizable. It is dependent upon the initial feed particle sizes. In other words, the simulations of product size distributions for fossil fuels were in good agreement with the experimental data using a ball mill simulation program, called JKSimMet. 17 refs., 5 figs., 2 tabs.

  7. Circuit high pressure grinding rolls (HPGR) in a cement grinding plant. Pt. 1. Evaluation of overall performance

    Energy Technology Data Exchange (ETDEWEB)

    Aydogan, Namik A.; Ergun, Levent [Hacettepe Univ., Ankara (Turkey). Mining Engineering Dept.

    2010-07-01

    In this paper, the performance of a closed circuit HPGR operation was evaluated by the data obtained from six measurements in a cement grinding circuit operating in Turkey. Flowrates of the streams and classifier performance were evaluated after mass balancing. The average specific energy consumption of the HPGR for six measurements was 9.62 kWh/t for grinding from 17.9 mm to 57 {mu}m (80 % passing size). Reduction ratio increased with the increase in specific energy consumption. Although cut point and the bypass of the classifier varied in a rather wide range, reduced efficiency curve and imperfection values indicated that the sharpness of separation remained the same. (orig.)

  8. Grinding efficiency of a newly developed continuous annular-stirred bead mill. Part 1; Shisakushita renzoku anyura gata shisshiki baitai kakuhan miru no funsai seino. 1

    Energy Technology Data Exchange (ETDEWEB)

    Kamiwano, M.; Kaminoyama, M.; Arai, K. [Yokohama National Univ. (Japan). Faculty of Engineering; Inoue, Y.; Hase, K. [Inoue Mfg. Inc., Kanagawa (Japan)

    1993-09-20

    Commonly, in ink, coating or the fields of chemical, medical, food, electric industries, as a dispersing purpose of grinding the solid particles and making the agglutinating particles into one-time particles, various stirred bead mills are widely used. In this paper, for the purpose of developing a grinding machine of which the grinding of feed through a mill was uniform and its product is fine and has a narrow particle size distribution, a continuous annular-stirred bead mill, which a cylindrical rotor with regularly arranged geometric protuberances on surface was installed in a cylinder with water jacket, was produced for trial and the grinding efficiency of this mill was investigated. Then, the shape of the protuberances on the surface and the grinding effect were investigated. Its results were shown that a rotor with protuberance, the side of which is vertical to the rotational direction of a rotor, has the highest grinding efficiency. 13 refs., 11 figs.

  9. Digital technology for radiometric thickness gages in rolling mills

    International Nuclear Information System (INIS)

    In this paper a nuclear (Am-241, Sr-90) computer-controlled thicknessgerge is described, utilizing the digital technologies additionally for transmission and filtration of signals of the receiver for automatic computation of the calibration curves, automatic standardization over the gauge range and on-line digital diagnosis. This device works without contact and can be used in cold and hot rolling mills. (orig.)

  10. Grinding efficiency of a newly developed continuous annular-stirred bead mill. Part 2.; Effect of various grinding factors on grinding efficiency; Shisakushita renzoku anyura gata shisshiki baitai kakuhan miru no funsai seino. 2.; Funsai seino ni oyobosu shuju no funsai inshi no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kamiwano, M.; Kaminoyama, M.; Arai, K. [Yokohama National Univ. (Japan). Faculty of Engineering; Inoue, Y.; Hase, K. [Inoue Mfg. Inc., Kanagawa (Japan)

    1993-09-20

    Recently, the stirred bead mills have many kinds and types, and their applications become wider. In this paper, effects of various factors on the grinding efficiency in a newly developed spike mill and the disk-stirred bead mill were investigated, a grinding equation can be obtained based on the power law. Also, effects of each factor on the grinding efficiency in the spike mill and in the disk-stirred bead mill were compared quantitatively. As a result, it was found that since the filled grinding medium was ground uniformly and effectively by a rotor in the spike mill, effect of the filled ratio of the grinding medium on the grinding efficiency was remarkable compared to that in the disk-stirred bead mill. It was also shown that the grinding feed through the spike mill was compared with that through the disk-stirred bead mill in the same case of the filled ratio of the grinding medium mentioned above, effect of the apparent residence time was remarkably found. 7 refs., 6 figs., 2 tabs.

  11. Service behaviour of high speed steel rolling rolls used in hot strip mills

    International Nuclear Information System (INIS)

    Work rolls used in hot strip mills may be able to carry out severe actions: very high thermal stresses and wear, along with mechanical stresses due to normal rolling loads, which develop in the presence of cracks, produced by the former actions. The microstructure and the mechanical behaviour (strength and toughness) of high speed steels, which recently have been introduced in this applications, were studied in this work in comparison with high chromium cast irons. (Author) 7 refs

  12. A study of energy-size relationship and wear rate in a lab-scale high pressure grinding rolls unit

    Science.gov (United States)

    Rashidi Dashtbayaz, Samira

    This study is focused on two independent topics of energy-size relationship and wear-rate measurements on a lab-scale high pressure grinding rolls (HPGR). The first part of this study has been aimed to investigate the influence of the operating parameters and the feed characteristics on the particle-bed breakage using four different ore samples in a 200 mm x 100 mm lab-scale HPGR. Additionally, multistage grinding, scale-up from a lab-scale HPGR, and prediction of the particle size distributions have been studied in detail. The results obtained from energy-size relationship studies help with better understanding of the factors contributing to more energy-efficient grinding. It will be shown that the energy efficiency of the two configurations of locked-cycle and open multipass is completely dependent on the ore properties. A test procedure to produce the scale-up data is presented. The comparison of the scale-up factors between the data obtained on the University of Utah lab-scale HPGR and the industrial machine at the Newmont Boddington plant confirmed the applicability of lab-scale machines for trade-off studies. The population balance model for the simulation of product size distributions has shown to work well with the breakage function estimated through tests performed on the HPGR at high rotational speed. Selection function has been estimated by back calculation of population balance model with the help of the experimental data. This is considered to be a major step towards advancing current research on the simulation of particle size distribution by using the HPGR machine for determining the breakage function. Developing a technique/setup to measure the wear rate of the HPGR rolls' surface is the objective of the second topic of this dissertation. A mockup was initially designed to assess the application of the linear displacement sensors for measuring the rolls' weight loss. Upon the analysis of that technique and considering the corresponding sources of errors, the application of the 2D distance measurement sensors was studied to directly determine the wear rate on the lab-sale HPGR roll. Results obtained from various grinding tests revealed that the operating variations were beyond the expected wear rate. Based on the valuable outcomes from the two mentioned experimental designs, a cup-disc arrangement similar to piston-die apparatus was developed to indirectly measure the wear rate on the HPGR roll. The preliminary outputs proved to be promising for further investigation into the development of this method in order to relate the measured data on the cup-disc apparatus to the actual wear rate on the HPGR rolls.

  13. Development of rolling mill for rectangular orthodontic wires production

    OpenAIRE

    Totten, G. E.; Filho, A. I.; Gouve?a, C. A. R.; Neto, A.; Casteletti, L. C.

    2007-01-01

    Purpose: In orthodontic treatments, wires of different metallic alloys are used for alignment, leveling, correction of the molar position, space closing, finish and retention. The purpose of the paper is the characteristics of austenitic stainless steel wires, with a square traverse section, which were produced using a rolling mill built for this purpose, are presented hereDesign/methodology/approach: With respect to finish and retention, these wires are responsible for adequate positioning o...

  14. Optimization of a Heavy Continuous Rolling Mill System Via Simulation

    OpenAIRE

    Ali Azadeh; Farid Ghaderi

    2006-01-01

    The objective of this study was to develop an integrated simulation model, which generates a set of optimizing alternatives for a heavy continuous rolling mill system in a full-scale steelmaking factory. The simulation approach enabled us to evaluate the performance of the existing system and pinpointed existing bottlenecks in workstations and production flow. Consequently, it generated a set of optimum production alternatives. Data related to process and operation times, repairs, maintenance...

  15. Development of rolling mill for rectangular orthodontic wires production

    Directory of Open Access Journals (Sweden)

    G.E. Totten

    2007-09-01

    Full Text Available Purpose: In orthodontic treatments, wires of different metallic alloys are used for alignment, leveling, correction of the molar position, space closing, finish and retention. The purpose of the paper is the characteristics of austenitic stainless steel wires, with a square traverse section, which were produced using a rolling mill built for this purpose, are presented hereDesign/methodology/approach: With respect to finish and retention, these wires are responsible for adequate positioning of the upper teeth on the lower teeth. Wires that are subjected to incisor torque require high resistance and stiffness. For this, wires of rectangular austenitic stainless steel are used due to high modulus of elasticity and good corrosion resistance in the oral environment. Because of the rectangular geometry, wire production requires process development suitable for industrial scale manufacture with geometric characteristics and mechanical properties better adapted to the use conditions.Findings: To obtain wires with such characteristics, a rolling mill was developed for the production of rectangular wires by a rolling process with the objective of reducing cost of the cold drawing process that is currently used which utilize complex and expensive wire-drawing dies. In addition to the rolling process itself, wire deformation, microhardness, tension and bend tests were also performed.Research limitations/implications: A rolling-mill was built that successfully produced dental wires within acceptable tolerances and physical/mechanical properties.These wires exhibited excellent hardness and tensile strength, although slightly less than analogous commercial wires. It is expected that this problem are corrected by using initial wires with a higher hardness, since this property is directly related with the tensile strength.Originality/value: In these tests, wire geometry, surface finish and mechanical properties were successfully adapted for use in orthodontic treatments.

  16. Differential speed two roll mill pretreatment of cellulosic materials for enzymatic hydrolysis.

    Science.gov (United States)

    Tassinari, T; Macy, C

    1977-09-01

    Differential speed two roll milling is an effective pretreatment for increasing the susceptibility of cellulose to enzymatic hydrolysis. Using mills with three, six, and ten in. diam rolls and processing times of 10 min or less results in the following percent increases in susceptibility over untreated controls: cotton, 1100; maple chips, 1600; white pine chips, 600; newspaper, 125. In comparison, ball milling of newspaper for 24 hr gives only a 62% increase. A further advantage of the roll mill is the increased wet density of the product permitting higher slurry concentrations during hydrolysis. Important parameters of mill effectiveness are roll clearance and processing time PMID:890083

  17. Crush Grinding

    International Nuclear Information System (INIS)

    Crush Grinding is a special process used at the Kansas City Plant to finish stem sections of reservoir products. In this process, a precise profile of the desired product is formed on a tungsten carbide roll. This roll slowly transfers a mirror image of the profile onto the grinding surface of a wheel. The transfer rate of the profile is between 0.001 and 0.010 inches per minute. Crush grinding is desirable since it provides consistent surface finishes and thin walls at a high production rate. In addition, it generates very sharp fillet radii. However, crush grinding is a complex process since many variables affect the final product. Therefore, the process requires more attention and knowledge beyond basic metal removal practices. While the Kansas City Plant began using these machines in 1995, a formal study regarding crush grinding has not been conducted there. In addition, very little literature is available in the grinding industry regarding this process. As a result, new engineers at the Kansas City Plant must learn the process through trial and error. The purpose of this document is to address this literature deficit while specifically promoting a better understanding of the stem crush grinding process at the Kansas City Plant.

  18. PENELITIAN OPTIMASI TEMPERATUR YANG MEMPENGARUHI KEKERASAN PADA PEMBUATAN GRINDING BALL DENGAN CARA HOT ROLLING

    Directory of Open Access Journals (Sweden)

    Amelia Amelia

    2000-01-01

    Full Text Available Hardness is one of the mechanical properties needed in a grinding ball. The hardness of grinding ball produced up to now is gained by trial and error to those parameters which are presumed influencing the hardness. Research is done to get parameter influence the hardness of grinding ball and optimum level. Three parameters presumed influencing the hardness are temperature of raw material (Tm, the initial temperature of quenching (Tq, and the final temperature of quenching (Tt. Design of experiment is used to analysis which parameter influence the hardness. A 23 factorial design is chosen, each parameter has two level. According to experiment and data analysis, the influencing parameter are Tq, Tt and interaction between Tq and Tt. The optimum value of Tq and Tt are 905 ± 10°C and 133 ± 3°C, value of Tm is 1110 ± 10°C. Abstract in Bahasa Indonesia : Kekerasan merupakan salah satu sifat yang dibutuhkan oleh grinding ball. Untuk mendapatkan sifat tersebut hingga saat ini masih dilakukan dengan cara trial and error sehingga sangatlah tidak efektif. Maka dari itu dilakukan suatu penelitian untuk mengetahui parameter-parameter yang mempengaruhi kekerasan grinding ball dan level yang optimal. Ada tiga parameter yang diduga mempengaruhi kekerasan grinding ball, yaitu temperatur raw material (Tm, temperatur awal proses quenching (Tq dan temperatur akhir proses quenching (Tt. Untuk menganalisa parameter-parameter yang berpengaruh digunakan desain eksperimen. Desain eksperimen yang digunakan adalah rancangan faktorial 23, masing-masing terdiri atas 2 level. Dari percobaan dan analisa data, tampak bahwa parameter yang berpengaruh adalah Tq, Tt serta interaksi antara Tq dan Tt. Nilai Tq dan Tt yang optimum adalah 905 ± 10°C dan 133 ± 3°C, sedang nilai Tm yang dianjurkan 1110 ± 10°C. Kata kunci: Desain eksperimen, grinding ball, temperatur quenching

  19. 119Sn Moessbauer spectroscopy in nanocrystalline alumina-tin composites synthesized by direct grinding and reactive ball milling

    International Nuclear Information System (INIS)

    Alumina-tin nanocomposites have been synthesized by direct grinding of ?-Al2O3-?-Sn powder mixtures, as well as by reactive milling of Al-SnO2 mixtures. According to the preparation method used, the composites differ from one another mainly in the amount of a disordered SnOx (x ? 1.1) phase and in the structural characteristics of alumina. (orig.)

  20. Influence of a matrix on properties of mottled cast iron applied for mill rolls

    OpenAIRE

    Krawczyk, J.; Pacyna, J.

    2010-01-01

    Mill rolls are ones of the most expensive tools applied in plastic working processes and have to satisfy several criteria, which allow them to be used. Cast iron mill rolls, due to their fracture toughness and tribological properties, are the most often applied at hot-rolling in the last rolling stands. This results from the smallest dynamic loads of such rolling stands and the decisive influence of the surface quality of these tools on the surface quality of the rolled product. An improper m...

  1. Mixing models to improve gauge prediction for cold rolling mills.

    Czech Academy of Sciences Publication Activity Database

    Ettler, P.; Andrýsek, Josef

    Québec City : Université Laval, 2007, s. 443-447. [MMM 2007 - 12th IFAC Symposium on Automation in Mining, Mineral and. Québec City (CA), 21.09.2007-23.09.2007] R&D Projects: GA AV ?R 1ET100750401; GA MŠk 1M0572 Institutional research plan: CEZ:AV0Z10750506 Keywords : rolling mill * prediction * industrial control * feedback control Subject RIV: BB - Applied Statistics, Operational Research http://as.utia.cz/publications/2007/EttAnd_07.pdf

  2. Bayesian model mixing for cold rolling mills: Test results.

    Czech Academy of Sciences Publication Activity Database

    Ettler, P.; Puchr, I.; Dedecius, Kamil

    Slovensko : Slovak University of Technology, 2013, s. 359-364. ISBN 978-1-4799-0926-1. [19th International Conference on Process Control. Štrbské Pleso (SK), 18.06.2013-21.06.2013] R&D Projects: GA MŠk(CZ) 7D09008; GA MŠk 7D12004 Keywords : Bayesian statistics * model mixing * process control Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/2013/AS/dedecius-bayesian model mixing for cold rolling mills test results.pdf

  3. Optimize cold sector material flow of a steel rolling mill

    OpenAIRE

    Baudet, Alvaro

    2010-01-01

    The steel production is a highly capital and energy intensive industry that due to recent raw materials’ price increase and lowered demand, it has been squeezed and forced to look more deeply on how to add value to the customer at lower operative costs. The project was carried out on site at the ArcelorMittal’s millin Esch-Belval, Luxembourg which comprises an integrated melt shop, continuous casting plant and the rolling mill with the objectives of proposing optimization rules for the co...

  4. Optimization of a Heavy Continuous Rolling Mill System Via Simulation

    Directory of Open Access Journals (Sweden)

    Ali Azadeh

    2006-01-01

    Full Text Available The objective of this study was to develop an integrated simulation model, which generates a set of optimizing alternatives for a heavy continuous rolling mill system in a full-scale steelmaking factory. The simulation approach enabled us to evaluate the performance of the existing system and pinpointed existing bottlenecks in workstations and production flow. Consequently, it generated a set of optimum production alternatives. Data related to process and operation times, repairs, maintenance and quality control were collected and analyzed systematically. The simulation model was modeled by Visual SLAM and Awesim simulation language. The results and structure of the computer simulation model were validated and verified against the actual system. Also, the results of the models were discussed and approved by the production managers. The distinct feature of the simulation model is three fold. First, it is integrated and considers detailed operations and activities of the Rolling Mill system. Furthermore, it is designed to be integrated with other workshops of the factory. Second, it locates the optimum solutions by a rule-based methodology. Finally, the model considers the Just-in-Time configuration of the line and is capable of answering all production and inventory issues.

  5. Grinding Wear Behaviour of Stepped Austempered Ductile Iron as Media Material During Comminution of Iron Ore in Ball Mills

    International Nuclear Information System (INIS)

    An attempt has been made to evaluate the suitability of austempered ductile iron (ADI) as media material for grinding iron ore in a ball mill. Spheroidal graphite (S.G) iron balls are austenitised at 900 deg. C for 60 minutes and given stepped austempering treatment at 280 deg. C for 30 minutes and 60 minutes followed by 380 deg. C for 60 minutes in each case. These materials are characterised by measuring hardness, analysing X-ray diffraction (X-RD), studying microstructure using optical and scanning electron microscope (SEM). Grinding wear behaviour of these materials was assessed for wear loss in wet condition at different pH value of the mineral slurry and found that the wear rate of grinding media material decreases with increase in pH of the slurry. The wear resistance of ADI balls were compared with forged En31 steel balls and found that the stepped austempered ductile iron is superior to forged En31 steel balls.

  6. INVESTIGATION OF THE MAINTENANCE ORGANISATION FOR HOT ROLLING MILLS

    Directory of Open Access Journals (Sweden)

    P.K. Pretorius

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Production systems have undergone dramatic changes in recent years. Many companies have implemented new technologies such as flexible manufacturing systems. There is therefore a shift in focus to maintenance and the effective management thereof. Maintenance is a dynamic activity and is comprised of a large number of interacting variables. An effective maintenance organisation is required to control these variables .
    This paper discusses the building of a maintenance organisation and the aspects that should be considered during the design. The way in which five companies that operate hot rolling mills apptoached the problem of building an effective maintenance organisation was investigated.

    AFRIKAANSE OPSOMMING: y eryaardigingstelsels het drastiese veranderinge ondergaan die afgelope aantal jaar. Verskeie Il1~atskappyemaak nou gebruik van nuwe tegnologiee, soas byvoorbeeld aanpasbare vervaardigingstelsels. Daar is gevolglik 'n verskuiwing in fokus na instandhouding en die effektiewe bestuur daarvan. lnstandhouding is 'n dinamiese aktiwiteit en behels 'n groot aantal ' gekoppelde veranderlikes. 'n Effektiewe instandhoudingsorganisasie word benodig om hierdie v'eranderlikes te beheer.
    Hierdie artikel bespreek die daarstelling van die instandhoudingsorganisasie en die parameters V~toorweeg moet word tydens die ontwerp. Die wyse waarop vyf maatskappye wat }V~rIl1walse bedryf die ontwikkeling van 'neffektiewe organisasie vir instandhouding benader hc(is ondersoek .

  7. Drop deformation in two-roll mills considering wall effects

    Science.gov (United States)

    Escalante-Velázquez, C. A.; Huesca-Reyes, M. A.; Yescas Rosas, I.; Geffroy, E.

    2015-01-01

    Experimental, theoretical and numerical results of dynamics of drop deformation in strong flows generated by a co-rotating two-roll mill and considering the influence of near rigid walls are presented. The drop dynamics is altered, with respect to a drop free of wall effects, by the proximity of the rigid boundaries as well as caused by a non-linear and non-uniform flow due to gradients of flow-type parameter and shear rate. Simulations were carried out using the Boundary Element Method (BEM). Since the inclusion of the whole boundaries (drop and rollers surfaces) is not an easy and trivial task, bi-dimensional numerical simulations was performed as a first approach. The experimental and numerical results were obtained for a flow type of ? = 0.03 and two values of viscosity ratio ? = 0.012 and 16. In general, numerical results for the stationary deformation parameters, up to intermediate confinements, are in agreement with the experiments, with and without wall effects. Since the case of drops with a high viscosity ratio did not match existing theoretical models, the wall-effect theory of Shapira and Haber was modified, considering Cox's second-order theory as the converging theory without wall effects. From low to intermediate confinements, the new Cox-Shapira-Haber model fitted the observed experimental deformations.

  8. Premature failure analysis of forged cold back-up roll in a continuous tandem mill

    International Nuclear Information System (INIS)

    Highlights: ? Metal wrapping and strip welding in work/back-up rolls contact zone caused spalling. ? MnS inclusion and pore initiated crack which propagated in milling led to spalling. ? Retained austenite conversion to ?'-martensite accelerated spalling failure. ? Needle shaped carbide (Fe,Mo,Cr)7C3, may cause poor service life of back-up roll. -- Abstract: In this paper, premature failure of a forged back-up roll from a continuous tandem mill was investigated. Microstructural evolutions of the spalled specimen and surface of the roll were characterized by optical microscopy, X-ray diffraction, scanning electron microscopy and ferritscopy, while hardness value of the specimen was measured by Vickers hardness testing. The results revealed that the presence of pore and MnS inclusion with spherical and oval morphologies were the main contributing factors responsible for the poor life of the back-up roll. In addition, metal pick up and subsequently strip welding on the surface of the work roll were found as the major causes of failure in work roll which led to spalling occurrence in the back-up roll. Furthermore, relatively high percentage of retained austenite, say 9%, in outer surface of the back-up roll contributed spalling due to conversion of this meta-stable phase to martensite and creation of volume expansion on the outer surface through work hardening during mill campaign.

  9. Mass exchange dynamic in the system layer on the surface of grinding body-charge powder at mechanical alloyuing and vibrating mill

    International Nuclear Information System (INIS)

    The role of layers-scrabs in the mechanism of secondary particle formation under grinded polydeformational aggregation (GPDA) of nickel and copper alloys in vibrational mill is revealed. It is shown that in the course of grinded polydeformational aggregation (mechanical alloying) dynamic exchange between the processed material, moving freely inside the mill volume and the material, bonded during the earlier processes on the grinded body surface takes place; and the exchange character is close to dynamic equilibrium with the rate of material receipt and shipment making up 0.5-1% of the charge mass per hour. It is shown, that accelerated layer distruction may occur in the end of the process: in this case the upper layer sections are the first to be separated and then - the deeper layer sectios

  10. A model-based predictive control scheme for steal rolling mills using neural networks

    OpenAIRE

    Gálvez J. M.; Zárate Luis E.; Helman H.

    2003-01-01

    A capital issue in roll-gap control for rolling mill plants is the difficulty to measure the output thickness without including time delays in the control loop. Time delays are a consequence of the possible locations for the output thickness sensor, which usually is located some distance away from the roll gap. In this work, a new model-based predictive control law is proposed. The new scheme is a neural network based predictive control structure which is applied to roll-gap control with outs...

  11. Advanced Soft Sensor Technology to be Used for Cold Rolling Mills.

    Czech Academy of Sciences Publication Activity Database

    Ettler, P.; Dedecius, Kamil; Juri?i?, D.; Preglej, A.

    Toulouse : IEEE, 2011, s. 1-4. ISBN 978-1-4577-0016-3. [16th IEEE International Conference on Emerging Technologies and Factory Automation ETFA'2011. Toulouse (FR), 05.09.2011-09.09.2011] R&D Projects: GA MŠk(CZ) 7D09008 Institutional research plan: CEZ:AV0Z10750506 Keywords : soft sensor * rolling mill Subject RIV: IN - Informatics, Computer Science http://library.utia.cas.cz/separaty/2011/AS/dedecius-advanced soft sensor technology to be used for cold rolling mills.pdf

  12. Extended Kalman Filter Based Neural Networks Controller For Hot Strip Rolling mill

    International Nuclear Information System (INIS)

    The present paper deals with the application of an Extended Kalman filter based adaptive Neural-Network control scheme to improve the performance of a hot strip rolling mill. The suggested Neural Network model was implemented using Bayesian Evidence based training algorithm. The control input was estimated iteratively by an on-line extended Kalman filter updating scheme basing on the inversion of the learned neural networks model. The performance of the controller is evaluated using an accurate model estimated from real rolling mill input/output data, and the usefulness of the suggested method is proved

  13. High Temperature Thermal Expansion and Elastic Modulus of Steels Used in Mill Rolls

    Science.gov (United States)

    Laptev, Alexander; Baufeld, Bernd; Swarnakar, Akhilesh Kumar; Zakharchuk, Stanislav; van der Biest, Omer

    2012-02-01

    The high temperature thermal expansion coefficient (TEC) and elastic modulus of five steels used in mill rolls production were investigated by dilatometer and impulse excitation techniques (IET). The measurements were provided at heating from room temperature till temperatures of about 1000 °C and subsequent cooling. The obtained data were attributed to the properties of predominating phases (austenite, martensite, pearlite, and bainite). The TEC and elastic modulus of corresponding phases were similar for all investigated steels despite the difference in their chemical composition. The steels with a chromium content of 2.95 wt.% and more show enhanced ability to quench hardening. This is an important prerequisite for production of high quality mill rolls.

  14. Production of sponge iron powder by reduction of rolling mill scale

    OpenAIRE

    Marti?n Herna?ndez, Mari?a Isabel; Lo?pez Go?mez, Fe?lix Antonio; Torralba Castello?, Jose? Manuel

    2012-01-01

    Rolling mill scale is a solid by-product of the steelmaking industry that contains metallic iron (Fe) and three types of iron oxides: wustite (FeO), hematite (?-Fe2O3) and magnetite (Fe3O4). It also contains traces of non-ferrous metals, alkaline compounds and oils from the rolling process. A study is made of the reduction of mill scale to sponge iron using coke at different temperatures and times. The reduced samples are studied by X-ray diffraction (XRD) and scanning electron microscopy (S...

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

    International Nuclear Information System (INIS)

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

  16. Force prediction in cold rolling mills by polynomial methods

    Directory of Open Access Journals (Sweden)

    Nicu ROMAN

    2007-12-01

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

  17. Control method for steel strip roughness in Two-stand temper mill rolling

    Science.gov (United States)

    Li, Rui; Zhang, Qingdong; Zhang, Xiaofeng; Yu, Meng; Wang, Bo

    2015-05-01

    How to control surface roughness of steel strip in a narrow range for a long time has become an important question because surface roughness would significantly influence the appearance of the products. However, there are few effective solutions to solve the problem currently. In this paper, considering both asperities of work roll pressing in and squeezing the steel strip, two asperity contact models including squeezing model and pressing in model in a two-stand temper mill rolling are established by using finite element method (FEM). The simulation investigates the influences of multiple process parameters, such as work roll surface roughness, roll radius and roll force on the surface roughness of steel strip. The simulation results indicate that work rolls surface roughness and roll force play important roles in the products; furthermore, the effect of roll force in the first stand is opposite to the second. According to the analysis, a control method for steel strip surface roughness in a narrow range for a long time is proposed, which applies higher work roll roughness in the first stand and lower roll roughness in the second to make the steel strip roughness in a required narrow range. In the later stage of the production, decreasing the roll force in the first stand and increasing the roll force in the second stand guarantee the steel strip roughness relatively stable in a long time. The following experimental measurements on the surface topography and roughness of the steel strips during the whole process are also conducted. The results validate the simulation conclusions and prove the effect of the control method. The application of the proposed method in the steel strip production shows excellent performance including long service life of work roll and high finished product rate.

  18. Fuzzy-Neural Control of Hot-Rolling Mill

    Directory of Open Access Journals (Sweden)

    Khearia Mohamad

    2010-12-01

    Full Text Available This paper deals with the application of Fuzzy-Neural Networks (FNNs in multi-machine system control applied on hot steel rolling. The electrical drives that used in rolling system are a set of three-phase induction motors (IM controlled by indirect field-oriented control (IFO. The fundamental goal of this type of control is to eliminate the coupling influence though the coordinate transformation in order to make the AC motor behaves like a separately excited DC motor. Then use Fuzzy-Neural Network in control the IM speed and the rolling plant. In this work MATLAB/SIMULINK models are proposed and implemented for the entire structures. Simulation results are presented to verify the effectiveness of the proposed control schemes. It is found that the proposed system is robust in that it eliminates the disturbances considerably.

  19. Regulated rolling of thick-sheet steel using 2800 mill

    International Nuclear Information System (INIS)

    A study was made on possibility of thermal strengthening of sheet low-alloy steel of up to 16 mm thickness, using heat of rolling heat and cooling in the system of automatic controlling temperature of rolling termination (SACTRT). It was recommended to produce 10KhSND steel sheets of 14 mm and less thickness with 0.46 and more factor of chemical composition according to the following technology: to terminate rolling in finishing stand at 870...900 deg.C and then to cool them in SACT RT down to 650...750 deg.C. The developed technology provides the complex of mechanical properties in accordance with requirements of 19282-73 All Union State Standard for 90% of metal. Sheets with unsatisfactory properties are subjected to heat treatment, beginning from special heating

  20. Method of expressing and evaluating the grinding proceedings of fine particles ground with continuous annular-stirred bead mill; Renzoku anyuragata shisshiki baitai kakuhan miru ni okeru biryushi no bunsai shinko jokyo no hyoji to hyokaho

    Energy Technology Data Exchange (ETDEWEB)

    Kamiwano, M.; Kaminoyama, M.; Nishi, K. [Yokohama National Univ., Yokohama (Japan). Dept. of Material Sciences and Chemical Engineering; Inoue, Y.; Suzuki, T. [Inoue MFG., Inc., Kanagawa (Japan)

    1999-09-10

    We propose indices of sharpness, S{sub s}{sup *} and representative diameter, D{sub s}{sup *}, for evaluation of grinding proceeding, both of which are defined through an integrated area along cumulative frequency curves undersize of a particle diameter distribution. We investigate dynamic changes of particle diameter distribution with these indices. It was found that these indices, S{sub s}{sup *} and D{sub s}{sup *} can express more accurately the subtle characteristics of the grinding process, which can not be described sufficiently with the grinding indices, S{sub s} and D{sub s}, defined through the Rosin-Rammler approximation. Subsequently, we evaluate the grinding proceedings for various kinds of rotor types and grinding media for the continuously stirred bead mill, with S{sub s}{sup *} and D{sub s}{sup *}. It was found from the evaluation that the continuous annular-stirred mill, on the Spike mil, can even grind talc particles, but the cumulative diameter distribution becomes broader. S{sub s}{sup *} and D{sub s}{sup *} can express more accurately that the Spike mill, with the narrower clearance between rotor and mill vessel wall, using smaller zirconia beads con grind calcium carbonate particles most satisfactorily. (author)

  1. Soft Starting Arrangements Availables for Hot Rolling Mills for Energy Conservation

    Science.gov (United States)

    Bisen, A. M.; Bapat, P. M.; Gagnuly, S. K.

    2012-07-01

    The conventional rolling mills in India are producing a major part of structural steel requirement of the country. The energy conservation in these rolling mills can be achieved mainly by reducing the size of the prime mover i.e. main electric motor. The power consumption per ton can be considerably decreased through proper selection of electric motor since it has been an observation by many surveyors[1] that the selection of electric motor of the rolling mill has been almost five to ten times on the higher side which can be easily verified from the power consumption and motor working data.Flywheel is a mechanical storage device. Largest size of flywheels are frequently recommended for smooth running of rolling mills. The main difficulty encountered in selecting large capacity flywheel or flywheel gear box system is the starting of the mill with smaller capacity electric motor. The starting characteristic of electric motor is not suitable for starting such rolling mill with very high inertia flywheel. In such condition it becomes very essential to introduce the soft starting arrangement for the electric motor so that considerably small size motor can start the flywheel effectively.Soft starters are used for the smooth start-up control of three-phase induction motors. The soft starter is functionally located between the Flywheel and the electric motor. In selecting the correct soft starter to suit the application the peculiarities of the soft start should be considered. In the prevailing conditions we use the motor of high horse power due to the fact that the flywheel requires high torque to be driven initially. For the same reason the efficiency of the flywheel is very low initially. Once the flywheel stores sufficient power which is required at the start up, the flywheel then requires less power than given initially. If we somehow are able to increase the efficiency of the flywheel using a flexible electrical, mechanical, hydraulic or flexible drives with different combinations (Electrical, Mechanical, Hydraulic) then the motor of less horse power can thus be installed to run the flywheel.This paper gives an idea of available type of the soft starting arrangement for a rolling mill so that horse power of motor can be reduced without affecting the working of the mill. Hence optimum selection of the soft starting arrangement is to be done so that initial and billing cost will be less.

  2. Calculation and experimental technique of determination of rolling procedure for cold-rolling tube mills

    International Nuclear Information System (INIS)

    Calculation and experimental technique of determination of tube cold rolling procedure has been developed. Rolling procedure based on the usage of regression equation epsilon=1.24 psi, where psi is the relative reduction of area, delta-permissible reduction during rolling, has been tested on 08Kh18N10T steel. The effect of tube geometry, tool calibration parameters, lubrication conditions etc. on metal deformability in taking into account experimentally. The use of the technique proposed has allowed to shorten the time of mastering of the production of tubes from different steels

  3. Influence of a matrix on properties of mottled cast iron applied for mill rolls

    Directory of Open Access Journals (Sweden)

    J. Krawczyk

    2010-07-01

    Full Text Available Mill rolls are ones of the most expensive tools applied in plastic working processes and have to satisfy several criteria, which allow them to be used. Cast iron mill rolls, due to their fracture toughness and tribological properties, are the most often applied at hot-rolling in the last rolling stands. This results from the smallest dynamic loads of such rolling stands and the decisive influence of the surface quality of these tools on the surface quality of the rolled product. An improper microstructure of rolls can lead to their premature wearing, e.g. broken flanges, pivots twisting off etc. By means of the heat treatment the matrix microstructure and morphology of carbide precipitationscan be modified and this in-turn can influence cast iron properties.Determination of the influence of microstructure changes, caused by the heat treatment, on the properties of EN-GJN-HV300 low-alloycast iron, after its modification and spheroidization – is the aim of the present paper. Those changes are based on the formation pearlitic or bainitic matrices at the similar morphology of graphite and ledeburitic cementite precipitations. The performed investigations should enable designing the heat treatment of cast iron metallurgical rolls in such a way as to obtain the optimal microstructures for functional parameters of these type of tools. The influence of changing the pearlitic matrix into the bainitic one on such properties as: hardness, impact strength, tensile strength, creep limit, bending strength and a stress intensity factor KIc was investigated in this study. Samples for testing, the listed above mechanical properties, were taken from an industrial casting with care to have pieces of very similar crystallization conditions.

  4. Lubricant for clean rolling: Escapee oil particles keep cold rolling steel mills lubricated:

    OpenAIRE

    Graaf, A.

    2002-01-01

    One of the unique selling points of the Corus steel mills at IJmuiden is the quality of the steel they produce. The lubrication used during the last production stage is one of the factors that determine how clean and smooth the steel will emerge from the mill. The usual lubricant consists of an emulsion of oil in water. Until recently, little was known about the physical principles underlying the action of lubricant emulsions in steel mills. The only way to test new lubricants was by...

  5. Preparation Model Based Control System For Hot Steel Strip Rolling Mill Stands

    Science.gov (United States)

    Bouazza, S. E.; Abbassi, H. A.; Moussaoui, A. K.

    2008-06-01

    As part of a research project on El-hadjar Hot Steel Rolling Mill Plant Annaba Algeria a new Model based control system is suggested to improve the performance of the hot strip rolling mill process. In this paper off-line model based controllers and a process simulator are described. The process models are based on the laws of physics. these models can predict the future behavior and the stability of the controlled process very reliably. The control scheme consists of a control algorithm. This Model based Control system is evaluated on a simulation model that represents accurately the dynamic of the process. Finally the usefulness to the Steel Industry of the suggested method is highlighted.

  6. Online Prediction under Model Uncertainty Via Dynamic Model Averaging: Application to a Cold Rolling Mill.

    Czech Academy of Sciences Publication Activity Database

    Raftery, A. E.; Kárný, Miroslav; Ettler, P.

    Volume 52, Number 1 (2010), s. 52-66. ISSN 0040-1706 R&D Projects: GA MŠk 1M0572; GA MŠk(CZ) 7D09008 Institutional research plan: CEZ:AV0Z10750506 Keywords : prediction * rolling mills * Bayesian Dynamic Averaging Subject RIV: BC - Control Systems Theory Impact factor: 1.560, year: 2010 http://library.utia.cas.cz/separaty/2010/AS/karny-0342595.pdf

  7. Effect of powder milling on mechanical properties of hot-pressed and hot-rolled Cu–Cr–Nb alloy

    International Nuclear Information System (INIS)

    Highlights: •Milled powder enhances sintering and mechanical properties after hot pressing. •Hot-rolling of hot-pressed samples made from milled powder enhances ductility. •Pore size and number of pores decreases after hot-rolling. -- Abstract: The present study is on the effect of mechanical milling of gas-atomized powders on mechanical properties of the hot-pressed and subsequently hot-rolled Cu–8 at% Cr–4 at% Nb alloy with a microstructure consisting of pure copper matrix hardened by intermetallic Cr2Nb precipitates. The mechanically milled powders result in lower sintering temperature during hot pressing compared to the atomized powders. The hot-pressed samples made from the milled powder exhibit significantly higher hardness and tensile strength, but lower ductility and electrical conductivity compared to that made from the un-milled gas-atomized powders. The hot rolling results in marginal increase in strength, but significant increase in ductility compared to the hot-pressed alloy for both the milled and atomized powders and it is attributed to the decrease in size of the pores and amount of porosities after hot rolling

  8. A comparison of the results obtained from grinding in a stirred media mill lignite coal samples treated with microwave and untreated samples

    Energy Technology Data Exchange (ETDEWEB)

    S. Samanli [Zonguldak Karaelmas University, Zonguldak (Turkey). Mining Engineering Department

    2011-02-15

    Various studies have been carried out on the effect of microwave-treatment on grinding different types of coal. However, the effect of microwave treatment on grinding coal samples -3.35 mm in size which can be considered to be fine is still under investigation. The purpose of this paper is to make contributions to these studies conducted. In the study, lignite coal samples with pyritic sulphur and 25% structural moisture were crushed below -3.35 mm particle size using jaw and cone crushers and then classified into three different mono size groups by Russel sieve. For a complete removal of the structural moisture from the lignite coal, a microwave application with 600 W needs approximately 35% more energy consumption than that with 850 W. The untreated coal samples and the ones treated with microwave at 850 W were ground for 5, 15, 30, 60, 120 s in a stirred media mill. The breakage rates of microwave-treated coal increased and accordingly the ground products of microwave-treated coal yielded finer particles than -106 {mu}m as compared to untreated coals. The untreated and microwave-treated feed coals of -3350 {mu}m and -1180 {mu}m particle sizes were ground for 2 min in the stirred media mill. It was found that the increases in the rate of weight percentages for -106 {mu}m particle size fraction after 2 min of grinding of untreated and microwave-treated feed coals of -3350 {mu}m and -1180 {mu}m were found to be 15.81% and 2.69%, respectively. Moreover, Hardgrove Index (HGI) test results of lignite coal showed that the HGI index value increased by approximately 23% after microwave treatment with 850 W. 37 refs., 11 figs., 4 tabs.

  9. Neural compensation and modelling of a hot strip rolling mill using radial basis function

    Scientific Electronic Library Online (English)

    F.G., Rossomando; J., Denti F; A., Vigliocco.

    2011-07-01

    Full Text Available In this paper a Neural Compensation Strategy for a hot rolling mill process is proposed. The target of this work is to built a RBF-NN compensation approximation for the classical force feed forward and speed controller. A strategy based on neural networks is proposed here, because they are capable o [...] f modelling many nonlinear systems and their neural control via RBF-NN approximation. Simulations demonstrate that the proposed solution deals with disturbances and modeling errors in a better way than classic solutions do. The analysis of the RBF-NN approximation error on the control errors is included, and control system performance is verified through simulations.

  10. Simulation of accelerated strip cooling on the hot rolling mill run-out roller table

    International Nuclear Information System (INIS)

    Full text: A mathematical model of the thermal state of the metal on the run-out roller table of a continuous wide hot-strip mill is presented. The mathematical model takes into account the heat generation during the polymorphic ? ? ? transformation of super cooled austenite phase and the influence of chemical composition on the physical properties of the steel. The model allows the calculation of modes of accelerated cooling of strips on the run-out roller table of a continuous wide hot strip mill. Winding temperature calculation error does not exceed 20 °C for 98.5 % of the strips from low-carbon and low-alloyed steels. key words: hot rolled, wide-strip, accelerated cooling, run-out roller table, polymorphic transformation, mathematical modeling

  11. Steel balls forming by cross rolling with upsetting

    Directory of Open Access Journals (Sweden)

    Z. Pater

    2013-01-01

    Full Text Available The paper describes a process of forming four balls with a diameter of 22 mm by means of cross rolling with upsetting. The paper also presents the tool used to form semi-finished balls. Owing to the application of the finite element method (FEM, the course of the rolling process as well as temperature and strain distributions in the obtained balls could be presented. The rolling tests conducted in laboratory conditions at the Lublin University of Technology have proved that the balls produced with the developed rolling method meet the demands for grinding media used in ball mills.

  12. Power quality at Gerdau MRM Steel : a rolling mill`s perspective

    Energy Technology Data Exchange (ETDEWEB)

    Shymanski, W.T. [Gerdau MRM Steel, Selkirk, MB (Canada)

    1998-12-31

    Power quality issues facing Gerdau MRM Steel, a steel mill operation in Selkirk, Manitoba were discussed. It was noted that power interruptions in various process equipment result in production loss, but the effects of harmonics and surges are harder to quantify. Some equipment, such as DC drives, variable-speed AC drives, computers and solid state equipment are sensitive to short term drop-outs and harmonic distortion. This type of equipment can also cause harmonic distortion. Some causes of sags, drop-outs and interruptions such as weather, switching, faults, accidents and human error were also reviewed. It was concluded that power quality problems at the plant can be resolved with support from the electric utility as well as from plant operations.

  13. Transport, mixing and stretching in a chaotic Stokes flow: The two-roll mill

    International Nuclear Information System (INIS)

    We present the outline and preliminary results of an analytical and numerical study of transport, mixing, and stretching in a chaotic Stokes' flow in a two-roll mill apparatus. We use the theory of dynamical systems to describe the rich behavior and structure exhibited by these flows. The main features are the homoclinic tangle which functions as the backbone of the chaotic mixing region, the Smale horseshoe, and the island chains. We then use our detailed knowledge of these structures to develop a theory of transport and stretching of fluid in the chaotic regime. In particular, we show how a specific set of tools for adiabatic chaos- the adiabatic Melnikov function lobe area and flux computations and the adiabatic switching method is ideally suited to develop this theory of transport, mixing and stretching in time-dependent two-dimensional Stokes' flows. 19 refs., 8 figs

  14. Reduction of wheat middlings using a conventional and eight-roller milling systems

    OpenAIRE

    Vukmirovi? ?uro M.; Fišteš Aleksandar Z.

    2009-01-01

    Possibilities for the rationalization of the wheat flour milling process using the eightroller mill on the 1M and 2M passages of the reduction system have been investigated. At the same roll gaps and under the same sieving conditions, the lower flour yield has been obtained using an eight-roller mill compared to the conventional milling system (5-8 %) followed by a higher energy requirements for grinding. By decreasing the roll gap setting and increasing the upper size limit of flour in the p...

  15. An investigation of worn work roll materials used in the finishing stands of the hot strip mill for steel rolling

    OpenAIRE

    Nilsson, Maria; Olsson, Mikael

    2012-01-01

    The surface failure characteristics of different work roll materials, i.e. high speedsteel, high chromium iron and indefinite chill iron, used in the finishing stands of a hot stripmill have been investigated using stereomicroscopy, three-dimensional optical profilometry, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results show that the surface failure mechanisms of work rolls for hot rolling are very complex, involving plastic deformation, abrasive wear, adhesi...

  16. Internal grinding of high-speed steels: Shorter processing times with boron nitride grinding tools

    Science.gov (United States)

    Borse, D.

    Boron nitride grinding tools can be used to advantage for the grinding of high speed steel (HSS) with a high vanadium content. the abrasives available to date are of limited value because the HSS materials contain very hard carbides, grinding of which, and of vanadium carbide in particular, results in very rapid wear in silicon carbide or corundum grinding wheels. The hardness of these steels is usually 62 RC to 70 RC. Boron nitride grinding tools are advantageous for internal grinding of workpieces made of high speed steel for example, sockets, milling tool bores, cutting wheels and crushing rollers. To date, boron nitride grinding wheels or pencil grinders were bonded with synthetic resin. Consequently internal grinding is usually carried out as wet grinding. In the meantime grinding tools bonded with electrodeposited metal bonds (GSS) were developed and proved to be successful for internal grinding. The abrasive grains which are arranged in a single layer protrude freely from the electrobond. During grinding very little heat is generated, so that dry grinding is possible.

  17. The Physical Flow of Materials and the Associated Costs in the Production Process of a Rolling Mill

    OpenAIRE

    Holisz-Burzy?ska, J.; Staniewska, E.; Budzik, R.

    2007-01-01

    Efficiency of resources use is, in a large extent, determined by the organization of production flow and the way of their control. The optimization of materials flow in the production process requires the identification of physical flows of goods and it cost. In the article the physical flow process of materials stream in the production process in one of Polish rolling mill and also its logistics analysis and cost analysis are presented.

  18. Genetic based sensorless hybrid intelligent controller for strip loop formation control between inter-stands in hot steel rolling mills.

    Science.gov (United States)

    Thangavel, S; Palanisamy, V; Duraiswamy, K

    2008-04-01

    Safe operating environment is essential for all complex industrial processes. The safety issues in steel rolling mill when the hot strip passes through consecutive mill stands have been considered in this paper. Formation of sag in strip is a common problem in the rolling process. The excessive sag can lead to scrap runs and damage to machinery. Conventional controllers for mill actuation system are based on a rolling model. The factors like rise in temperature, aging, wear and tear are not taken into account while designing a conventional controller. Therefore, the conventional controller cannot yield a requisite controlled output. In this paper, a new Genetic-neuro-fuzzy hybrid controller without tension sensor has been proposed to optimize the quantum of excessive sag and reduce it. The performance of the proposed controller has been compared with the performance of fuzzy logic controller, Neuro-fuzzy controller and conventional controller with the help of data collected from the plant. The simulation results depict that the proposed controller has superior performance than the other controllers. PMID:18093589

  19. "Grinding" cavities in polyurethane foam

    Science.gov (United States)

    Brower, J. R.; Davey, R. E.; Dixon, W. F.; Robb, P. H.; Zebus, P. P.

    1980-01-01

    Grinding tool installed on conventional milling machine cuts precise cavities in foam blocks. Method is well suited for prototype or midsize production runs and can be adapted to computer control for mass production. Method saves time and materials compared to bonding or hot wire techniques.

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

    Directory of Open Access Journals (Sweden)

    Behzad BahramiNejad

    2015-03-01

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

  1. Failure analysis of work rolls of a thin hot strip mill

    Directory of Open Access Journals (Sweden)

    Piyas Palit

    2015-04-01

    Destructive testing (including metallography and chemical analysis was carried out on the failed roll samples in the first case and gross abnormality in microstructure was observed. Some foreign particle/entrapment was observed after dressing of the working surface of roll at 566 mm diameter (initial diameter of roll was 620 mm and scrap diameter was projected to be 540 mm. The chemical composition of the particle was analyzed by a portable X-Ray Fluorescence (XRF alloy analyzer and it was confirmed that the particle is basically a ferroalloy which was entrapped in the shell of the roll, probably during casting/manufacturing of roll.

  2. Influence of structure and properties of tubular billets of the 12 Kh 18N10T steel on deformability of tubes at cold-rolling mills

    International Nuclear Information System (INIS)

    Metallographic analysis of the defects of the ''oblique cracks'' type on the surface of hot-rolled tubes of the 12Kh18N10T steel has been carried out. Recommended is the complex of mechanical properties and the structure factors (grain size) of conversion hot-rolled tubes, providing the combination of ductility and high rapture strength during rolling at pilger mills. At a grain size not coarser than number 5, a billet must have ?sub(T) 5>=40 %. Hot-rolled coarse-grained billet is not recommended for warm rolng because of high strain hardening

  3. Catalytic surface modification of roll-milled poly(?-caprolactone) biaxially stretched to ultra-thin dimension

    International Nuclear Information System (INIS)

    A novel roll-milling polymer processing technique along with biaxial stretching was used to fabricate 10 ?m thick poly(?-caprolactone) films. A less invasive collagen surface modification was used, involving a reaction between corona-preactivated membranes and ferrous-containing acrylic acid solution at the low temperature of 42 oC. Successful modified films were characterized by Toluidine Blue O assay and X-ray photoelectron spectroscopy. Human umbilical vein endothelial cells also showed both higher proliferation rate and differentiated cobblestone morphology on these collagen-immobilized substrates

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

    OpenAIRE

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

    2013-01-01

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

  5. Wear testing of fine ceramic grinding bodies by tracer techniques

    International Nuclear Information System (INIS)

    According to the gamma spectra, the lanthanum content of neutron-activated fine ceramic grinding bodies seems to be a suitable tracer for the wear testing of grinding mills. The method is based on the post-activation analysis of the grist samples taken from the mill. Experimental data prove that the lanthanum-free sand grist is proportional to the wear of the ginding bodies, i.e. the wear can be calculated in case the weights of the grist as well as the grinding bodies are known. The advantage of the method is that the wear can be determined at any time, without taking the grinding bodies out of the mill and cleaning them. In addition, after a long grinding period, a uniform material distribution from the grinding bodies has been found. (A.L.)

  6. Planejamento e controle da produção de cilindros para laminação: um estudo de caso quantitativo / Production management of rolling mill rolls: a quantitative study case

    Scientific Electronic Library Online (English)

    Laerte José, Fernandes; Luis Alberto Osés, Rodriguez; Anderson Ribeiro, Correia; Fernando Augusto Silva, Marins.

    2013-03-01

    Full Text Available Este trabalho apresenta um modelo de otimização-simulação aplicado em um estudo de caso real no setor de cilindros para laminação de uma siderúrgica, buscando melhorar o gerenciamento da área/equipamento gargalo da linha de produção. A simulação atuou em conjunto com um modelo de otimização da progr [...] amação linear inteira (PLI) para melhorar o atendimento de prazo junto aos clientes em uma produção não seriada. Como resultado deste procedimento combinado da PLI e simulação, o processo produtivo foi otimizado e as filas de espera e o lead-time foram reduzidos, melhorando o atendimento aos clientes. Abstract in english This article presents a simulation-optimization model application for a real case study in the rolling mill roll sector of a steel plant. The purpose of this study was to get a better area/equipment bottleneck management in the production line. The simulation was used together with an ILP (Integer L [...] inear Programming) optimization model, in order to improve customer service in a made-to-order production. As a result of this ILP and Simulation combined approach, the productive process was optimized and both queues and lead-time were reduced, improving customer service.

  7. Planejamento e controle da produção de cilindros para laminação: um estudo de caso quantitativo Production management of rolling mill rolls: a quantitative study case

    Directory of Open Access Journals (Sweden)

    Laerte José Fernandes

    2013-03-01

    Full Text Available Este trabalho apresenta um modelo de otimização-simulação aplicado em um estudo de caso real no setor de cilindros para laminação de uma siderúrgica, buscando melhorar o gerenciamento da área/equipamento gargalo da linha de produção. A simulação atuou em conjunto com um modelo de otimização da programação linear inteira (PLI para melhorar o atendimento de prazo junto aos clientes em uma produção não seriada. Como resultado deste procedimento combinado da PLI e simulação, o processo produtivo foi otimizado e as filas de espera e o lead-time foram reduzidos, melhorando o atendimento aos clientes.This article presents a simulation-optimization model application for a real case study in the rolling mill roll sector of a steel plant. The purpose of this study was to get a better area/equipment bottleneck management in the production line. The simulation was used together with an ILP (Integer Linear Programming optimization model, in order to improve customer service in a made-to-order production. As a result of this ILP and Simulation combined approach, the productive process was optimized and both queues and lead-time were reduced, improving customer service.

  8. Preparation of super-clean coal. Effect of media size in stirred ball mill grinding. Technical progress report for the ninth and tenth quarters, September 15, 1985-March 14, 1986

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, R.H.; Adel, G.T.; Mankosa, M.J.

    1986-05-01

    As a prerequisite to producing super-clean coal with any physical coal cleaning process, such as microbubble flotation, the feed coal must be micronized to liberate finely disseminated mineral matter. The stirred ball mill is regarded as one of the most efficient devices for micronizing coal. Using a five-inch batch mill, the optimum operating conditions have been determined in terms of media size, the optimum operating conditions have been determined in terms of media size and media type. The rates of breakage determined with monosized feeds are compared on the basis of specific energy consumption. It has been found that a 20:1 ball size/particle size ratio gives optimum grinding conditions. 10 refs., 10 figs.

  9. Maintenance strategy for tilting table of rolling mill based on reliability considerations

    International Nuclear Information System (INIS)

    Reliability centred maintenance (RCM) is a new strategic framework for ensuring that any asset continues to perform, as its users want it to perform. RCM is a process used to determine the maintenance requirement of any physical asset in its operating context. RCM process entails asking seven questions about each of the selected assets. It makes use of two documents namely, RCM information worksheet and RCM decision worksheet. RCM decision diagram integrates all the decision processes into a single strategic framework. RCM concept developed by US commercial airlines industry has been successfully implemented by Military, Navy, Nuclear power plants, electric power generation and distribution undertakings and several other sectors. These projects have been carried out in the United Kingdom, The Republic of Ireland, the United States, Hong Kong, Australia, Spain and Singapore. The fact that people has enthusiastically received RCM at all levels and has enabled users to achieve some remarkable successes in all of these countries, suggests that it can be universally employed. Literature review indicates that RCM approach is not conventionally applied in process industries in India. Presently, predictive maintenance (PDM) approach along with conventional preventive maintenance is used in continuous/process industries. This approach if implemented in totality will increase the production cost to a large degree and make the production uneconomical. Similarly breakdown mainten uneconomical. Similarly breakdown maintenance (BDM) approach cannot be applied in such industries as each breakdown involves huge costs. RCM approach is a compromise between PDM and BDM approach for optimising the cost and ensuring the availability of machine. The RCM approach has been applied to the tilting table system of rolling mill for the research work reported in this paper. In the present study, preventive maintenance tasks suggested for power transmission subsystem, guiding and transportation subsystem and hydraulic subsystem in tilting tables are 14 scheduled on-condition tasks, 10 scheduled on-restoration tasks, seven scheduled discard task. Whereas for 14 failure modes no scheduled maintenance has been proposed. Existing maintenance schedule for tilting tables indicates the maintenance action as and when required. Hence RCM based schedule specifies that additional preventive maintenance tasks need to be executed as compared to none initially. Cost incurred for this can be offset from the savings accrued from reduction in loss of production due to repetitive breakdowns. The methodology of RCM adopted in western industries cannot be applied as it is to Indian industries because of labour oriented nature, partially computerised information systems, non-availability of the information about cost of loss of production due to breakdown and age-reliability pattern of equipment, insufficient maintenance database. These problems can be overcome by development of sound MMIS, formulation of RCM review group and imparting suitable training to acquire the relevant skills in RCM. Thus RCM methodology can be applied to Indian industry for reduction of breakdowns as well as optimisation of preventive maintenance cost. This can further boost up the prospects of Indian industry to offer the products at globally competitive prices

  10. Sheet production using powder rolling of nickel and titanium alloys

    International Nuclear Information System (INIS)

    Based on information contained in literature, patents and catalogs a review is presented of powder-rolling metallurgy abroad. Statistics are given on the output of powder metallurgy in several countries. In the USA both the dense type of rolled metal for manufacturing various machine parts and the porous variety for making filters are produced. Four main types of technological processes are analysed: the usual flow chart for cold rolling, rolling of preheated powder, rolling in free-flowing state, and rolling with heated rollers. Of these four processes the first is most widely used. Fowders consisting of spherical particles (heat-stable alloys from nickel or high titanium alloys), which are difficult to work with, have not yet found wide practical application in powder metallurgy abroad. Literature data show that granulated heat-resistant alloys can be cold-treated under pressure only after they are powdered. The best methods for pulverizing are: cold-stream granulation and grinding with the aid of vibrational mills. Vacuum rolling of powders and rolling with electrically preheated rollers are especially promising in rolling powders that are difficult to deform

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

    Scientific Electronic Library Online (English)

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

    2013-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Ricardo Floriano

    2013-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Ricardo Floriano

    2012-01-01

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

  14. Analysis of the technology of rolling 5,5 mm-diameter wire rod of cold upsetting steel in the morgan block mill

    Directory of Open Access Journals (Sweden)

    K. Laber

    2015-04-01

    Full Text Available The commercial technology of rolling 5,5 mm-diameter wire rod in Poland’s most modern rolling line has been examined within the study. The material used for the investigation was the 20MnB4 steel intended for subsequent cold working. From the performed analysis of the investigation results it has been found that the technology of rolling wire rod of cold upsetting steel, which is used currently in the Rolling Mill under examination, allows the production of finished products that can be deformed with a relative reduction of about 33 %. At larger plastic deformations,cracks occur in the material, which disqualifies it from further cold working.

  15. Finite element analysis of edge fracture of electrical steel strip in reversible cold rolling mill

    Energy Technology Data Exchange (ETDEWEB)

    Byon, Sang Min [Dong A Univ., Busan (Korea, Republic of)

    2012-12-15

    An electrical steel strip is commonly used as a core material in all types of electric transformers and motors. It is produced by a cold rolling process. In this paper, a damage mechanics based approach that predicts the edge fracture of an electrical steel strip during cold rolling is presented. We adopted the normal tensile stress criterion and the fracture energy method as a damage initiation criterion and a damage evolution scheme, respectively. We employed finite element analysis (FEA) to simulate crack initiation and propagation at the initial notch located at the edges of the strip. The material constants required in FEA were experimentally obtained by tensile tests using a standard and a notched sheet type specimen. The results reveal that the edge crack was initiated at the entrance of the roll bite and that it rapidly evolved at the exit. The evolution length of the edge crack increased as the length of the initial notch as well as front tension reel force of the strip increased.

  16. Comparison between a high chromium steel and a semi HSS grades used as work rolls in the roughing stands of a hot strip mill

    OpenAIRE

    Tchuindjang, Jérôme Tchoufack; Lecomte-Beckers, Jacqueline

    2010-01-01

    Two alloys grades for work rolls used in the roughing stand of Hot Strip Mill (HSM) were compared. The first grade known as High Chromium Steel (HCS) is actually the alloy widely used for such an application, while the second one known as semi-High Speed Steel (semi-HSS) is the new grade developed to improve overall properties of the work roll in the roughing stands of the HSM. In the present work, the new semi-HSS grade is studied starting from 3 chemical compositions closed one to anoth...

  17. Design of two bearings with sealing system for the top roll shaft of sugar cane mill

    Scientific Electronic Library Online (English)

    Walter, Mora Perdomo; John Sandro, Rivas Murillo; John Jairo, Coronado Marín.

    2005-12-01

    Full Text Available Las chumaceras de bronce utilizadas actualmente en los molinos de caña de azúcar presentan elevado desgaste debido, entre otros factores, a la materia extraña que ingresa en ella cuando el eje superior se eleva (flota) por efecto del colchón de caña que pasa entre las mazas y al sobrecalentamiento c [...] ausado por fallas en los sistemas de lubricación y refrigeración. Con el objetivo de solucionar estos problemas dos diseños de chumaceras fueron realizados: uno con refrigeración en la caja y otro con refrigeración en la teja, ambos usando un sistema de sellado. Análisis por Elementos Finitos del comportamiento mecánico y térmico de los diseños garantiza un buen desempeño en operación. Abstract in english The bronze bearings currently used in sugar cane mills undergo an excessive wear due to both, the extraneous matter entering in the bearing gap when the shaft lift by effect of cane passing through the mill and heating caused by failures in both the lubrication and the refrigeration systems. In orde [...] r to solve this problems two bearing were designed: one cooled in the box and other cooled in the roofing tile, both using a sealing system. Finite Elements Analysis of the designs showed that they will have a good mechanical and thermal performance.

  18. Using Variable Perturbation Method to Study the Stability of Torsional Self-Excited Vibration in Main Drive System of Rolling Mill

    Directory of Open Access Journals (Sweden)

    Fenglan Wang

    2013-06-01

    Full Text Available The self-excited vibration of blooming mill is a kind of torsional vibration, which occurs only when the rolling machine slips under appropriate conditions. Once in place, this may cause the larger peak pressure of each component in the main drive system; reduce the service life of the components, cause components? damage directly. A large number of studies have shown that, at present there are not effective methods for diagnosis, monitoring of slipping and take proper measures in time to stop slipping so as to avoid the occurrence of malignant accidents. In this paper, author set out from another angle, take the main drive system of rolling mill as an example, to study stability of self-excited vibration. The conditions of the stable vibration are gained. By combining with the actual working conditions of blooming mill, author has put forward some effective measures to meet the stable conditions in order to make the blooming mill work in the stable state. Practice research has proved that the effective measures can contribute to reduce structural damage directly caused by the torsional vibration when “slipping” phenomenon occurred and to extend the service life of the components.

  19. Improving Thermal Efficiency Of Push Type Furnace In A Hot Re-Rolling Steel Mill By Direct Method : Case Study

    Directory of Open Access Journals (Sweden)

    Jeetendra Mohan Khare

    2013-04-01

    Full Text Available Rolling is the process of reducing the thickness or changing the cross-section of a long work-piece by compressive forces applied through a set of rolls. Rolling accounts for about 90% of all metals produced by metalworking processes. The purpose of Rolling is to convert larger sections into smaller sections, which can be used directly in as rolled state or as stock for working through other processes. As a result of rolling, the coarse structure of cast ingot is converted into a fine grained structure

  20. Dry grinding with CBN wheels, the effect of structuring

    OpenAIRE

    Rabiey, Mohammad

    2011-01-01

    Although some of the machining processes with defined cutting edges like milling and turn-ing could be recently applied without coolant, the realization of the processes with undefined cutting edges like grinding is still a challenge for researches and a very interesting target for industry. Grinding involves high specific energy compared to other machining processes due to the stochastic nature of the grain distribution and negative rake angle of grains. A major part of this energy is conver...

  1. AISI/DOE Advanced Process Control Program Vol. 3 of 6: MICROSTRUCTURAL ENGINEERING IN HOT-STRIP MILLS Part 2 of 2: Constitutive Behavior Modeling of Steels Under Hot-Rolling Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yi-Wen Cheng; Patrick Purtscher

    1999-07-30

    This report describes the development of models for predicting (1) constitutive behaviors and (2) mechanical properties of hot-rolled steels as functions of chemical composition, microstructural features, and processing variables. The study includes the following eight steels: A36, DQSK, HSLA-V, HSLA-Nb, HSLA-50/Ti-Nb, and two interstitial-free (IF) grades. These developed models have been integrated into the Hot-Strip Mill Model (HSMM), which simulates the hot strip rolling mills and predicts the mechanical properties of hot-rolled products. The HSMM model has been developed by the University of British Columbia-Canada as a part of project on the microstructural engineering in hot-strip mills.

  2. Applications of High-Efficiency Abrasive Process with CBN Grinding Wheel

    OpenAIRE

    Yan Zhou; Changhe Li; Yali Hou

    2010-01-01

    High-efficiency abrasive process with CBN grinding wheel is one of the important techniques of advanced manufacture. Combined with raw and finishing machining, it can attain high material removal rate like turning, milling and planning. The difficult-to-grinding materials can also be ground by means of this method with high performance. In the present paper, development status and latest progresses on high-efficiency abrasive machining technologies with CBN grinding wheel relate to high speed...

  3. Intensification of Cement Grinding with Apply Grinding Aids with Modify Effect

    Directory of Open Access Journals (Sweden)

    Lyubov Dmitrievna Shakhova

    2014-08-01

    Full Text Available For over 60 years technological additives used in process of grinding cement. Application of cement grinding aids can improve performance of ball mills, reduce specific energy consumption, and increase fluidity of cement during transportation and processing. Construction practice is characterized currently emergence and increasing use of so-called high-tech (effective a new generation of concrete, suggesting the use of high quality cement. In work presents results of impact intensifiers on the grindability of cement based on different mineralogical composition of clinker. Offers original methodology for assessing of indicators intensifiers action on grinding process and qualitative characteristics of cement. Knowing positive and negative sides of each constituent component it is possible to try selection of compositions intensifiers with synergies effect considering mineralogical composition of clinker and material composition of cement. The presence of modifying component allows not only render intensifying effect in milling process, but to increase both early and late strength due to the formation of more dense and homogeneous structure of cement stone. It is shown that intensifiers with modifying additives allow not only affect on grinding process, but also on the process of hydration and morphology crystal hydrates, strength characteristics. In process of work we had determined, that among researched additives for two different cements, which differ from each other mineralogical composition, best results were obtained with used AI8 intensifier.

  4. Effects of High Pressure ORE Grinding on the Efficiency of Flotation Operations

    Science.gov (United States)

    Saramak, Daniel; Krawczykowska, Aldona; M?ynarczykowska, Anna

    2014-10-01

    This article discusses issues related to the impact of the high pressure comminution process on the efficiency of the copper ore flotation operations. HPGR technology improves the efficiency of mineral resource enrichment through a better liberation of useful components from waste rock as well as more efficient comminution of the material. Research programme included the run of a laboratory flotation process for HPGR crushing products at different levels of operating pressures and moisture content. The test results showed that products of the high-pressure grinding rolls achieved better recoveries in flotation processes and showed a higher grade of useful components in the flotation concentrate, in comparison to the ball mill products. Upgrading curves have also been marked in the following arrangement: the content of useful component in concentrate the floatation recovery. All upgrading curves for HPGR products had a more favourable course in comparison to the curves of conventionally grinded ore. The results also indicate that various values of flotation recoveries have been obtained depending on the machine operating parameters (i.e. the operating pressure), and selected feed properties (moisture).

  5. Outogenius! The testing of autogenous grinding in laboratory and pilot scale, and the design of full scale comminution circuits

    International Nuclear Information System (INIS)

    The design of autogeneous grinding mills is difficult because of the variability of their grinding media; when steel balls or rods are used as in SAG or non-autogenous machines, calculations can be much more reliable because--obviously--the characteristics of the media are constant, or predictable. But when the grinding medium and the feed material are one and the same thing, the variations in the physical characteristics of the feed multiply the design problems, especially in the case of autogenous primary mills. Now, however, researchers from Outokumpu, Finland, working backwards after years of studying full scale autogenous production mills, are developing a special laboratory method to test the suitability of ores for Outogenius comminution, Outokumpu's own autogenous grinding process. This paper discusses the results of these new grinding machines which use ores to grind ores. The specifications of the machinery are provided along with the performance on various types of ores

  6. A structured approach to the evaluation of the energy requirements of HPGR and SAG mill circuits in hard ore applications

    Scientific Electronic Library Online (English)

    P., Rosario; R., Hall.

    2010-03-01

    Full Text Available The application of high pressure grinding rolls (HPGR) has been growing in the mining industry for the last 10 to 15 years. The major benefits supporting this trend are better energy efficiency, improved grinding capacity, and higher metal recovery in downstream processes such as heap leaching and f [...] lotation. In general there is limited quantitative knowledge on the true benefits of HPGRs relative to SAG mills in comminution, and about which situations one deals with better than the other. This paper will present a structure for comparison of the energy requirements for HPGR versus SAG mill considering complete circuits for comminution of precious and base metals hard ores. The work presented is from the design of four complete circuits based on ore data from two sites.

  7. Mechanical activation of ultrafine cordierite: Effect of grinding time

    International Nuclear Information System (INIS)

    In these studies, cordierite was mechanically synthesized after a sol-gel process. The effect of milling time of cordierite was investigated. Aluminium nitrate nonahydrate, magnesium nitrate hexahydrate and tetraethyl orthosilicate (TEOS) were used as starting materials. Gels obtained were mechanically activated in planetary ball mill by at 300 rpm grinding speed and grinding time (15 min, 30 min, 45 min and 60 min). Powders produced were characterized by X-ray Diffraction (XRD) and Field Emission Scanning Microscope (FESEM) and Energy Dispersive X-ray (EDX). EDX analysis proved that ?-cordierite was formed at lower temperature (1200 degree Celsius) as compliment to without grinding, whereby it is formed at 1300 degree Celsius. FESEM analysis shows the size of the cordierite were in submicron scale. EDX analysis proved that magnesium, aluminium, silicon and oxygen are elements existed in cordierite. (author)

  8. Improving energy efficiency of reheating furnace of sheet ingot plant and rolling mill Calibers of Gecamines / Lubumbashi by the recovery of waste heat of smoke

    International Nuclear Information System (INIS)

    The economic management of energy is an important topic in industrial processes to the extent that it ensures the competitiveness of any firm and ensures its survival. Within this framework we plan to improve the energy efficiency of the powerful furnace for reheating lingots Rolling Mills and Cable Factory (of which the fuel is diesel) where we propose to install a head recovery exchanger between the hot fumes out of the oven (60 C) and combustion air taken initially at room temperature (250C). Without recovery the oven consumes on the average 101 liters of diesel per hour for its operation and yields a thermal efficiency of 68,6%. Whereas with recovery, it can reach a thermal efficiency of 86% on one of recoverers that we have proposed, and save up to 15,8 liters of diesel on its hourly consumption

  9. Stokes flow in a two-dimensional micro-device combined by a cross-slot and a microfluidic four-roll mill

    Science.gov (United States)

    Guan, Jing; Liu, Jinxia; Li, Xiaoduan; Tao, Jun; Wang, Jingtao

    2015-02-01

    The flow structures in a novel microfluidics device (CS-MFRM) combining a cross-slot (CS) and a microfluidics four-roll mill (MFRM) have been investigated through a two-dimensional boundary element method. By changing the volume flow rates at various inlets of a CS-MFRM, diverse flow structures can be generated. Some of them are proposed to be employed to achieve some functions in the fabrication process of anisotropic particles. The stagnant points and eddies in those flows are particularly discussed since they are critical to trap and/or rotate droplets. Energy consumption of eddies generated in branches in some flow structures is also investigated in this paper.

  10. Photoacoustic study of nanocrystalline silicon produced by mechanical grinding

    International Nuclear Information System (INIS)

    Mechanical grinding (MG) was used to produce nanocrystalline silicon and its thermal and transport properties were investigated by photoacoustic absorption spectroscopy (PAS). The experimental results suggest that in as-milled nanocrystalline silicon for 10 h the heat transfer through the crystalline and interfacial components is similar, and after annealed at 470 oC the heat transfer is controlled by crystalline component.

  11. High Performance Grinding and Advanced Cutting Tools

    CERN Document Server

    Jackson, Mark J

    2013-01-01

    High Performance Grinding and Advanced Cutting Tools discusses the fundamentals and advances in high performance grinding processes, and provides a complete overview of newly-developing areas in the field. Topics covered are grinding tool formulation and structure, grinding wheel design and conditioning and applications using high performance grinding wheels. Also included are heat treatment strategies for grinding tools, using grinding tools for high speed applications, laser-based and diamond dressing techniques, high-efficiency deep grinding, VIPER grinding, and new grinding wheels.

  12. THE INFLUENCE OF DIAGENETIC AND TECTONIC PROCESSES IN DOLOMITES ON THE GRINDING

    Directory of Open Access Journals (Sweden)

    Dragan Krasi?

    1990-12-01

    Full Text Available Origin and occurence of dolomites are important for the physical and mechanical properties, especially grinding. The influence of diagenetic and tectonic processes in dolomites on the grinding of rocks was investigated in samples from two diag-netically different deposit types, and that separately from the compact and tectonized part of the rock masses. The grinding tests were carried out in a ball mill. By petrographic and granulometric analysis as well as by determination of the grinding rate and Bond's Working Index it was found that the state of rock fissures influences the crushability down to grain sizes even of 1...2 mm, and that the grinding rate is lower for rocks of higher crystal lattice order and a higher content of small crystals. Also, samples with clean regular crystals, formed by recrystallization, manifest a stronger resistance to grinding.

  13. Grind hardening process

    CERN Document Server

    Salonitis, Konstantinos

    2015-01-01

    This book presents the grind-hardening process and the main studies published since it was introduced in 1990s.  The modelling of the various aspects of the process, such as the process forces, temperature profile developed, hardness profiles, residual stresses etc. are described in detail. The book is of interest to the research community working with mathematical modeling and optimization of manufacturing processes.

  14. Silicon Ingot Rod Grinding

    Science.gov (United States)

    This Quicktime animation shows the second main step in the silicon wafer development process after the ingots are cooled. This animation shows the process of grinding silicon ingots to the proper diameter. This happens before the wafers are cut into slices.The previous animation showing silicon crystal pulling can be seen here.The next animation in this sequence about wafer cutting can be seen here.

  15. Diretrizes para a construção de um moinho de bolas para a moagem de sólidos em laboratórios / Guidelines for the construction of a ball mill for grinding solids in the laboratory

    Scientific Electronic Library Online (English)

    Lucas F. de, Paula; Alberth C., Alves; Heden C. S., Alves; Edimar A., Ribeiro; Ana G. B., Madurro; João M., Madurro.

    Full Text Available [...] Abstract in english In this paper, we show the construction of a low-cost, high-quality ball mill for obtaining finely divided powders, with the goal of presenting guidelines for achieving the best results for the milling process. This equipment allows for the adjustment of the size of the mill in order to process diff [...] erent quantities of material. The construction of mechanical and electrical components that provide increased efficiency, the choice of milling medium, and frequent problems experienced with homemade ball mills are discussed.

  16. Application research of ferrous matrix composites in roller ring used in high-speed wire/bar rolling mill

    International Nuclear Information System (INIS)

    Research highlights: ? A composite structure roller rings was fabricated by centrifugal casting. ? The roller rings consisted of outer WCP/Fe-C composites layer and inner Fe-C alloy matrix. ? Hardness attained to HRA80-85 in the composites layer, and HRA73-76 in inner Fe-C alloy matrix where the toughness was over 8 J/cm2. ? The wear resistance of the roller rings excelled that of high-speed steel, and approached to that of the WC hard alloy roll. ? The production cost of the WCP/Fe-C composites roller ring decreased by 50%. - Abstract: Tungsten carbide particle (WCP) reinforced ferrous matrix composites roller rings were fabricated by centrifugal casting. The microstructures, properties and application effect of the composites roller rings were investigated by SEM, TEM and various property testers. The experimental results show that the WCP were uniformly distributed in outer reinforced-layer (working-layer) of 20-50 mm in thickness and their volume fraction reached 60-80 vol.%; there was a good interface bonding between WCP and Fe-C alloy without any reaction products; hardness attained to HRA80-85 in working-layer, and HRA73-76 in inner ferrous matrix where the toughness was over 8 J/cm2; the wear resistance of the composites roller rings excels that of high-speed steel; service life of the composites parts approached to that of the WC hard alloy roll when the same WCP-volume-fraction in woub>P-volume-fraction in working-layer were obtained for both of them, but the production cost of the WCP/Fe-C composites roller ring decreased by 50%.

  17. ONLINE SAG MILL PULSE MEASUREMENT AND OPTIMIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Raj Rajamani; Jose Delgadillo; Vishal Duriseti

    2006-06-24

    The grinding efficiency of semi autogenous milling or ball milling depends on the tumbling motion of the total charge within the mill. Utilization of this tumbling motion for efficient breakage of particles depends on the conditions inside the mill. However, any kind of monitoring device to measure the conditions inside the mill shell during operation is virtually impossible due to the severe environment presented by the tumbling charge. An instrumented grinding ball, which is capable of surviving a few hours and transmitting the impacts it experiences, is proposed here. The spectrum of impacts collected over 100 revolutions of the mills presents the signature of the grinding environment inside mill. This signature could be effectively used to optimize the milling performance by investigating this signature's relation to mill product size, mill throughput, make-up ball size, mill speed, liner profile and ball addition rates. At the same time, it can also be used to design balls and liner systems that can survive longer in the mill. The technological advances made in electronics and communication makes this leap in instrumentation certainly viable. Hence, the instrumented grinding ball offers the ability to qualitatively observe and optimize the milling environment.

  18. Assessment of air pollution and its effects on the health status of the workers in beam rolling mills factory (Iran National Steel Industrial Group from Ahvaz-Iran

    Directory of Open Access Journals (Sweden)

    Rafiei Masoud

    2009-01-01

    Full Text Available Background: Air pollutants of iron- and steel-making operations have historically been an environmental and health hazard. These pollutants include gaseous substances such as sulfur oxide, nitrogen dioxide, and carbon monoxide. The Iran National Steel Industrial Group beam rolling mills factory has two production lines viz. line 630 and line 650, with different beam production capabilities and is capable of producing different types of beams. Materials and Methods: A retrospective cross-sectional study on 400 workers in different exposure levels to environmental pollution was performed during 2005 to determine the mean value of respirable particulate matter (RPM concentrations and its effects on the health status of workers. To elicit information regarding the health status of the worker, the National Institute for Occupational Safety and Health standard questionnaire was used. Fisher?s exact test was performed to assess the relative risk (RR of exposure to air pollution on cardiovascular diseases, chest tightness, cough, difficulty in retention, i.e. loss of memory, tension, occupational fatigue, and occupational stress in exposed workers. Results: There was significant difference in RPM pollution level between two product lines. The RR of exposure to air pollution on cardiovascular diseases, chest tightness, cough, difficulty in retention, i.e. loss of memory, tension, occupational fatigue, and occupational stress in exposed workers were 2.78, 2.44, 2.15, 1.92, 1.57, 3.90, and 2.09, respectively.

  19. PARTICLE SIZE DISTRIBUTION OF WHEAT GRIST FRACTIONS IN PLANSIFTER COMPARTMENTS OF A FIVE BREAKS ROLLER MILL SYSTEM

    Directory of Open Access Journals (Sweden)

    GHEORGHE VOICU

    2013-06-01

    Full Text Available In wheat milling, it is particularly necessary that the grist particle size-distribution entering and exiting each plansifter compartment of the wheat mill to be determined so that the appropriate geometrical characteristics of flutes, grinding rolls and their functional parameters can be chosen and the characteristics of the sieves braids to be established to optimize flour, middling, and semolina yield and quality of them. The paper presents the particle size-distribution of wheat going through each break, in a five-break roller mill system with a capacity of 4.2 t/h and equipped with a semolina sorting compartment (divisor. The particle size distribution data where fit to the Rosin-Rammler distribution equation.

  20. Tensile mechanical behavior and fracture toughness of MWCNT and DWCNT modified vinyl-ester/polyester hybrid nanocomposites produced by 3-roll milling

    International Nuclear Information System (INIS)

    This study aims to investigate the tensile mechanical behavior and fracture toughness of vinyl-ester/polyester hybrid nanocomposites containing various types of nanofillers, including multi- and double-walled carbon nanotubes with and without amine functional groups (MWCNTs, DWCNTs, MWCNT-NH2 and DWCNT-NH2). To prepare the resin suspensions, very low contents (0.05, 0.1 and 0.3 wt.%) of carbon nanotubes (CNTs) were dispersed within a specially synthesized styrene-free polyester resin, conducting 3-roll milling technique. The collected resin stuff was subsequently blended with vinyl-ester via mechanical stirring to achieve final suspensions prior to polymerization. Nanocomposites containing MWCNTs and MWCNT-NH2 were found to exhibit higher tensile strength and modulus as well as larger fracture toughness and fracture energy compared to neat hybrid polymer. However, incorporation of similar contents of DWCNTs and DWCNT-NH2 into the hybrid resin did not reflect the same improvement in the corresponding mechanical properties. Furthermore, experimentally measured elastic moduli of the nanocomposites containing DWCNTs, DWCNT-NH2, MWCNTs and MWCNT-NH2 were fitted to Halphin-Tsai model. Regardless of amine functional groups or content of carbon nanotubes, MWCNT modified nanocomposites exhibited better agreement between the predicted and the measured elastic moduli values compared to nanocomposites with DWCNTs. s compared to nanocomposites with DWCNTs. Furthermore, Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used to reveal dispersion state of the carbon nanotubes within the hybrid polymer and to examine the CNT induced failure modes that occurred under mechanical loading, respectively. Based on the experimental findings obtained, it was emphasized that the types of CNTs and presence of amine functional groups on the surface of CNTs affects substantially the chemical interactions at the interface, thus tuning the ultimate mechanical performance of the resulting nanocomposites.

  1. Chiral Crystal Growth under Grinding

    OpenAIRE

    Saito, Yukio; Hyuga, Hiroyuki

    2008-01-01

    To study the establishment of homochirality observed in the crystal growth experiment of chiral molecules from a solution under grinding, we extend the lattice gas model of crystal growth as follows. A lattice site can be occupied by a chiral molecule in R or S form, or can be empty. Molecules form homoclusters by nearest neighbor bonds. They change their chirality if they are isolated monomers in the solution. Grinding is incorporated by cutting and shafling the system rand...

  2. Modeling of interferences during thread milling operation

    OpenAIRE

    Fromentin, Guillaume; Poulachon, Gérard

    2010-01-01

    Thread milling is becoming more and more employed as a technique for producing thread, due to its advantages for industrial manufacturing sectors, such as the aeronautics, aerospace, and energy industries. The thread milling operation is atypical and several aspects have to be taken into account to perform it in good conditions. As for milling or grinding worms, grooves, thread or others sculptured surfaces, in thread milling, there exists a geometrical interference between the tool and the n...

  3. Design of the Soymilk Mill based on TRIZ Theory

    Directory of Open Access Journals (Sweden)

    Jiang Fan

    2013-05-01

    Full Text Available The soymilk mill is an important food machine, but its volume is too large to be suitable for house using. This study first analyzes some problems in the soymilk mill miniaturization. For these problems, the thinking tools, evolutionary tools and contradiction solving tool of TRIZ theory are used to resolve the conflict in the integration of grinding and boiling and in the keep grinding effect, to tackle the optimization problem in the grinding stria structure and mill plate speed, then the Dwarfs method and substance-field analysis model is used in solving the interference and the conditions water supply problems which are encountered in the design of the global structure and a micro soymilk mill is designed. Finally, the mechanical analysis model about soy granules, soymilk particles in the grinding zone and the computational model of motor starting torque are obtained; they provide the reference data for application of soymilk mill.

  4. Computation of Rolling Stand Parameters by Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    František ?urovský

    2008-05-01

    Full Text Available Mathematical model of rolling process is used at cold mill rolling on tandemmills in metallurgy. The model goal is to analyse rolling process according to process datameasured on the mill and get immeasurable variables necessary for rolling control andoptimal mill pre-set for next rolled coil. The values obtained by model are used asreferences for superimposed technology controllers (thickness, speed, tension, etc. as well.Considering wide steel strip assortment (different initial and final thickness, differenthardness, and fluctuation of tandem mill parameters (change of friction coefficient, workrolls abrasion, temperature fluctuation, etc. the exact analysis of tandem is complicated.The paper deals with an identification of friction coefficient on a single rolling mill standby a genetic algorithm. Mathematical description of tandem mill stand is based on themodified Bland-Ford model. Results are presented in graphical form.

  5. Kinetics of Grinding of Secondary Serpentine Raw Material at Cascade Operating Mode

    Directory of Open Access Journals (Sweden)

    Marek Matik

    2004-12-01

    Full Text Available The paper deals with the grinding of secondary serpentine material from the Dob?iná´s heap in a ball ceramic mill. The raw material was pre-sieved to prepare fraction of +250 ?1,000 µm that was fed to the mill. During batch experiment an amount of oversize on the screen with a mesh size of 200 µm was observed as a function of time. Two speed modes were tested. Firstly, it was the mode designed by mill producer implicit from the structure of milling stand equipped by electromotor, friction gear onto driving shaft with given diameter. The speed of this original alignment attains 40 rmp. Secondly, it was cascade speed mode according to the Haase´s equation, namely 53 rmp, achieved by enlargement of driving shaft diameter. As to winning of required final product 90 % ?200 µm, increased speed resulted in the shortening of grinding time from 17.5 to15.7 hour.

  6. Surface Grinding Machine Stability Characteristics Limited Prediction

    OpenAIRE

    Yuting Yang; Jianzhong Lin; Shilong Xu

    2012-01-01

    The chatter in the grinding process has a great influence in improving work piece surface quality and production efficiency. The formula of flutter system limit grinding depth and the rotating speed of the grinding wheel are induced based on the chatter theory and the chatter dynamitic model of the grinding system. The computer modeling and simulation are carried out to get flutter stability predicted picture. Finally the reliability and validity of the predicted picture are verified by the e...

  7. Efficient Fuel Pretreatment: Simultaneous Torrefaction and Grinding of Biomass

    DEFF Research Database (Denmark)

    Saleh, Suriyati Binti; Hansen, Brian Brun

    2013-01-01

    Combining torrefaction and grinding of biomass in one reactor may be an attractive fuel pretreatment process. A combined laboratory torrefaction and ball mill reactor has been constructed for studies of the influence of temperature and residence time on the product yields and particle size reductions of Danish wheat straw, spruce chips, and pine chips. On the basis of initial experiments, which evaluated the influence of reactor mass loading, gas flow, and grinding ball size and material, a standard experimental procedure was developed. The particle size reduction capability of the torrefaction process has been evaluated by the relative change in d50, and this method was compared to the Hardgrove grindability index (HGI), showing reasonably similar results. Significant differences in torrefaction behavior have been observed for straw and spruce chips torrefied at 270–330 °C. Torrefaction of straw for 90 min yielded a higher mass loss (27–60 wt %) and relative size reduction (59–95%) compared with spruce (massloss of 10–56 wt % and size reduction of 20–60%). The two types of biomass investigated differ with respect to hemicellulose type, lignocellulosic composition, particle morphology, and ash composition, where straw has a higher alkali content. This and other studies indicate that the large difference in the alkali contents of the biomasses is the main cause for the observed difference in torrefaction characteristics. Experiments with separate particle heating and grinding showed a swift grinding of the torrefied biomass. This implies that the rate-limiting step in the laboratory reactor is the heat transfer and not the grinding process. Large pine particles (8–16 mm) showed a slightly higher mass loss than 4–8 and <4 mm particles. This could be the consequence of exothermic reactions in the particle core, which locally increase the temperature and conversion.

  8. Ceramic-bonded abrasive grinding tools

    Science.gov (United States)

    Holcombe, Jr., Cressie E. (Farragut, TN); Gorin, Andrew H. (Knoxville, TN); Seals, Roland D. (Oak Ridge, TN)

    1994-01-01

    Abrasive grains such as boron carbide, silicon carbide, alumina, diamond, cubic boron nitride, and mullite are combined with a cement primarily comprised of zinc oxide and a reactive liquid setting agent and solidified into abrasive grinding tools. Such grinding tools are particularly suitable for grinding and polishing stone, such as marble and granite.

  9. APPLICATION OF HACCP TO CONTROL MYCOTOXINS IN DRY GRIND ETHANOL BYPRODUCT PRODUCTION

    Science.gov (United States)

    Ethanol has been used as a fuel source in the United States since the early 1900’s and is seeing a renewed and increased interest as an alternative to petroleum. Today most fuel ethanol is produced by the dry grind mill process creating a valuable co-product, distillers dried grain with solubles (D...

  10. APPLICATION OF HACCP TO CONTROL MYCOTOXINS IN THE DRY GRIND ETHANOL PROCESS

    Science.gov (United States)

    Ethanol has been used as a fuel source in the United States since the early 1900’s and is receiving a renewed and increased interest as an alternative to petroleum. Today most fuel ethanol is produced by the dry grind mill process creating a valuable co-product, namely distillers dried grain with s...

  11. Photoisomerisation behaviour of azobenzene crystals hybridised with silica nanoparticles by dry grinding.

    Science.gov (United States)

    Ichimura, Kunihiro

    2010-05-21

    The dry grinding of azobenzene crystals with silica nanoparticles gave nanohybrids, which exhibited reversible photoisomerisation in water through linearly consecutive processes. The hybrids mill-dispersed in an aqueous PVA solution displayed different spectral changes due to the partial dissolution of azobenzene in PVA coils in water. PMID:20442891

  12. Roll-to-Roll production of carbon nanotubes based supercapacitors

    Science.gov (United States)

    Zhu, Jingyi; Childress, Anthony; Karakaya, Mehmet; Roberts, Mark; Arcilla-Velez, Margarita; Podila, Ramakrishna; Rao, Apparao

    2014-03-01

    Carbon nanomaterials provide an excellent platform for electrochemical double layer capacitors (EDLCs). However, current industrial methods for producing carbon nanotubes are expensive and thereby increase the costs of energy storage to more than 10 Wh/kg. In this regard, we developed a facile roll-to-roll production technology for scalable manufacturing of multi-walled carbon nanotubes (MWNTs) with variable density on run-of-the-mill kitchen Al foils. Our method produces MWNTs with diameter (heights) between 50-100 nm (10-100 ?m), and a specific capacitance as high as ~ 100 F/g in non-aqueous electrolytes. In this talk, the fundamental challenges involved in EDLC-suitable MWNT growth, roll-to-roll production, and device manufacturing will be discussed along with electrochemical characteristics of roll-to-roll MWNTs. Research supported by NSF CMMI Grant1246800.

  13. Rolling Stonesi kinokontsert kannab toorest rokiväge / Maris Meiessaar

    Index Scriptorium Estoniae

    Meiessaar, Maris

    2009-01-01

    Martin Scorsese muusikalisest dokumentaalfilmist "Shine a Light - Valgus peale" (USA-Suurbritannia, 2008), mille keskmes on 2006. a. New Yorgi Beaconi teatris toimunud briti ansambli Rolling Stones kontsert

  14. Surface grinding of intermetallic titanium aluminides

    CERN Document Server

    Gröning, Holger Andreas

    2014-01-01

    A deductive kinematic model of creep-feed and speed-stroke grinding processes is developed to identify possibilities to reduce the energy introduced into the workpiece. By computer tomography analysis and tactile measurements of the grinding wheel the pore volume and the static cutting edge number are determined and included in the model. Based on the kinematic model and the grinding wheel characteristics an analytical evaluation of the specific grinding energy for speed-stroke and creep-feed grinding is carried out. The deducted process design is evaluated in experimental investigations. The

  15. Production of grinding wheels with high grinding force ratio and high efficiency for glassy materials

    International Nuclear Information System (INIS)

    A new method to produce grinding wheels for glass materials is discussed. The production method maker uses pulsed electric current sintering (PECS). The new grinding wheels were evaluated by influencing factors, such as porosity, grinding forces, grinding pressure, and removal rate. A quick evaluation method of 'reciprocal grinding tests' is developed to estimate grinding ratio. In the reciprocal grinding test, porosity of around 30 % shows the higher grinding force ratio. Apart of cost considerations, to obtain a high grinding ratio with grain size of 12-15 ? m and particle size of cast-iron of 11 ? m, the 30 % grain fraction is better than the 1.5 % and 7.5 % grain fraction. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  16. Contamination introduced during rock sample powdering. Effects from different mill materials on trace element contamination

    International Nuclear Information System (INIS)

    We examined blanks during powdering processes for thirty-three trace elements using ICP-MS (inductively coupled plasma mass spectrometry). Quartz sand was used as target of powdering with grinding mills of several kinds: an agate hand mill, agate ball mill, Fe hand mill, alumina ceramic hand mill and artificial crystalline quartz hand mill. The results show that the artificial crystalline quartz hand mill is the purest grinder among the analyzed ones. This grinder is suitable for soft rock samples such as limestone. The alumina ceramic hand mill can reduce contamination, except for Cs, W and Pb. The agate hand mill and the agate ball mill introduce contamination whose level is depending on the individual device due to heterogeneity of the natural agate. The Fe hand mill introduces contamination of some si-derophile elements such as Mo and W. The results of this study emphasize careful choice of a grinding mill for sample pulverizing. (author)

  17. The method of assessment of the grinding wheel cutting ability in the plunge grinding

    Science.gov (United States)

    Nadolny, Krzysztof

    2012-09-01

    This article presents the method of comparative assessment of the grinding wheel cutting ability in the plunge grinding kinematics. A new method has been developed to facilitate multicriterial assessment of the working conditions of the abrasive grains and the bond bridges, as well as the wear mechanisms of the GWAS, which occur during the grinding process, with simultaneous limitation of the workshop tests range. The work hereby describes the methodology of assessment of the grinding wheel cutting ability in a short grinding test that lasts for 3 seconds, for example, with a specially shaped grinding wheel, in plunge grinding. The grinding wheel macrogeometry modification applied in the developed method consists in forming a cone or a few zones of various diameters on its surface in the dressing cut. It presents an exemplary application of two variants of the method in the internal cylindrical plunge grinding, in 100Cr6 steel. Grinding wheels with microcrystalline corundum grains and ceramic bond underwent assessment. Analysis of the registered machining results showed greater efficacy of the method of cutting using a grinding wheel with zones of various diameters. The method allows for comparative tests upon different grinding wheels, with various grinding parameters and different machined materials.

  18. [Investigations on the shape and size of bone-chips produced during boring and grinding (author's transl)].

    Science.gov (United States)

    Paulsen, K

    1975-10-01

    Examinations of the shape and size of chips produced during boring and grinding of dry macerated and fresh temporal bone by various drills and grinders at different revolutions show that rose trepans mainly scrape fresh bone, producing large rolled-up chips, but knock off dry macerated bone, producing more compact chips of bizarre shape. In either case the chip waste also contains plenty of fine and finest compact chips which are broken off and splinter during the removal or knocking-off of the chips from solid bone. The size of the chip depends on the size of the drill head. Diamond cutting heads produce fine and finest compact bone chips. Bone milling produces plenty of scrapes even from dry macerated temporal bone. The rate of revolutions (10,000-80,000 per min) had no influence on the shape and size of chips. Clinically the scraped chip seems to be the most favourable in the drilling of bone because it causes least damage. The use of a drill head with sharp-edged, intact cutting surfaces seems important for this, with continuous rinsing during the boring process to prevent soiling of the interspaces between the cutters and to ensure full performance in accordance with their construction. PMID:129601

  19. VOLATILIZED LUBRICANT EMISSIONS FROM STEEL ROLLING OPERATIONS

    Science.gov (United States)

    The report gives results of a study of the volatilization of lubricants used in steel rolling. Data from nine steel mills were used to: define the volatilized portion of lubricants used in rolling; and prepare total oil, grease, and hydraulic material balances for actual and typi...

  20. Online SAG Mill Pluse Measurement and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Raj Rajamani; Jose Delgadillo; Vishal Duriseti

    2007-06-30

    The grinding efficiency of semi autogenous milling or ball milling depends on the tumbling motion of the total charge within the mill. Utilization of this tumbling motion for efficient breakage of particles depends on the conditions inside the mill. However, any kind of monitoring device to measure the conditions inside the mill shell during operation is virtually impossible due to the severe environment presented by the tumbling charge. An instrumented grinding ball, which is capable of surviving a few hours and transmitting the impacts it experiences, is proposed here. The spectrum of impacts collected over 100 revolutions of the mills presents the signature of the grinding environment inside mill. This signature could be effectively used to optimize the milling performance by investigating this signature's relation to mill product size, mill throughput, make-up ball size, mill speed, liner profile and ball addition rates. At the same time, it can also be used to design balls and liner systems that can survive longer in the mill. The technological advances made in electronics and communication makes this leap in instrumentation certainly viable. Hence, the instrumented grinding ball offers the ability to qualitatively observe and optimize the milling environment. An instrumented load cell package that can measure the force of impacts inside the grinding chamber of a mill is developed here. The signal from the instrumented load cell package is interpreted in terms of a histogram termed as an impact spectrum which is a plot of the number of impacts at a specific energy level against the energy. It reflects on the average force regime of the mill. The instrumented load cell package was calibrated against the ultra fast load cell which has been unanimously accepted as a standard to measure single breakage events. The load cell package was successfully used to produce impact spectra in an 8.5 inch lab scale mill. The mill speed and the ball size were varied to study their effect on the impact spectra. A good correlation was found between the process variables and the impact spectra. The load cell package was then used in a 16 inch pilot scale mill. The mill speed, ball size, and mill filling were varied here and a consistent trend between these variables and impact spectra was observed. With a better understanding developed from the initial tests, the design of the load cell package was significantly changed to eliminate noise. With the new design, the impact spectra were re-determined in the 16 inch pilot mill varying the process variables - ball size, mill speed, and mill filling. Finally, it is successfully shown that a change in the operating variables of a mill can be seen in the impact spectra and that this concept can be successfully developed to monitor the grinding operation of industrial mills. To adapt it to industrial level it is mandatory to make the load cell package wireless. A design of a wireless circuit that is capable of transferring data at the required speed of 1000 kbps was also developed and tested at Cortez Gold Mines (CGM), Nevada.

  1. Manufacturing processes 2 grinding, honing, lapping

    CERN Document Server

    Klocke, Fritz

    2009-01-01

    Presents a view of the most common machining and non-machining manufacturing processes. This volume describes the characteristics of abrasive tools, their design and manufacturing, followed by the fundamentals of grinding fluids. It also discusses grinding of different materials (steel, cast iron, hard and brittle materials, nickel and titanium).

  2. Theoretical considerations of machining with grinding wheels

    Directory of Open Access Journals (Sweden)

    Andrew Oyakhobo Odior

    2013-03-01

    Full Text Available Grinding is one of the most versatile methods of removing material from machine parts by the cutting action of the countless hard and sharp abrasive particles of a revolving grinding wheel. It works by forcing the abrasive grains into the surface of the workpiece so that each grain cuts away a small bit of material in the form of chips. Abrasive grinding wheel is an expendable wheel that carries an abrasive compound on its periphery. They are made of small, sharp and very hard natural or synthetic abrasive minerals, bonded together in a matrix to form a wheel. The paper presents a review of some of the characteristics as well as theoretical considerations of operations of abrasive grinding wheel. The relationships among the various grinding parameters; the radial force f, the force on individual grit of grinding wheel F, velocity of grinding wheelg Vg, velocity of work piecew Vw, the wheel diameterg Dg, and the diameter of the work piece Dw were established for given grinding operations.

  3. Lathe converted for grinding aspheric surfaces

    Science.gov (United States)

    Larmer, J. W.; Levinsohn, M.; Mc Craw, D.; Pessagno, E. H.; Taub, F. J.

    1964-01-01

    A standard overarm tracing lathe converted by the addition of an independently driven diamond grinding wheel is used for grinding aspheric surfaces. The motion of the wheel is controlled by the lathe air tracer following the template which produces the desired aspheric profile.

  4. Stirred media mills: Dynamics, performance, and physio-chemical aspects

    Science.gov (United States)

    Zheng, Jie

    While applications of stirred media mills for fine particle production have continued to grow, there is a lack of understanding of power requirements, optimum operating conditions and powder (product) characteristics underlying stirred media milling processes. To develop a physical understanding of stirred mill dynamics and scale-up principles, and to identify conditions and mechanisms for effective use of energy in fine grinding, the results of analysis of the literature and of tests in laboratory stirred media mills with media, limestone, and the effect of chemical additives as grinding aids are presented, and mill dynamics, performance and physico-chemical aspects are discussed. Four operational regions marked by sharp transitions are described: transition from static to dynamic friction; channeling; dispersion; and centrifugation. Equations, including power and modified Reynolds number, have been established for relating relevant operating and geometrical variables. Scale-up guidelines with respect to power consumption are also proposed. The best operating conditions for grinding limestone have been identified. The effect of additives on the grinding efficiency and the properties of ground product is discussed using the example of ultra fine grinding of limestone, in which more than a 100% increase in specific surface area and energy efficiency can be obtained. As solid concentration increases, media/pulp flow patterns pass through four regimes: vortex flow, rotating flow, layer formation above the impeller pins, and layer formation adjacent to the tank wall. Use of polyacrylic acid as an additive caused the media/pulp flow to move toward lower solid concentration situation, thus improving grinding conditions and resulting in better grinding. Fragmentation of the polymer molecules was found to occur during long term grinding and this was beneficial for ultrafine grinding. In summary, the research has led to the development of a physical understanding of mill dynamics, performance and physico-chemical effects in stirred media mills. The scale-up principles established, the optimum operating conditions identified and the mechanisms revealed in the use of grinding aids have pointed the way towards more efficient energy utilization during fine grinding in stirred media mills.

  5. Precision diamond grinding of ceramics and glass

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.; Paul, H.; Scattergood, R.O.

    1988-12-01

    A new research initiative will be undertaken to investigate the effect of machine parameters and material properties on precision diamond grinding of ceramics and glass. The critical grinding depth to initiate the plastic flow-to-brittle fracture regime will be directly measured using plunge-grind tests. This information will be correlated with machine parameters such as wheel bonding and diamond grain size. Multiaxis grinding tests will then be made to provide data more closely coupled with production technology. One important aspect of the material property studies involves measuring fracture toughness at the very short crack sizes commensurate with grinding damage. Short crack toughness value`s can be much less than the long-crack toughness values measured in conventional fracture tests.

  6. Spatial distribution studies of milling particles, milling charge and grist

    International Nuclear Information System (INIS)

    Applications of the narrow-beam?-ray method for dry grinding power technology are discussed. In a model of a vertically agitated ball-mill, the spatial distribution of model milling charge with and without model grist and the spatial distribution of the grist were investigated. The model volume was 10 litres. Polystyrene balls (diameter 4.5 mm) were used as a model of the milling charge and limestone -CaC03 of diameter 0.04-0.1 mm as a model of the grist. A system of mixing discs (10 rev s-1) on a coaxial shaft kept the mill-charge in vibrational motion. The results are presented in the form of graphs of the bulk density of the mill balls or the bulk density of the grist plotted against the height or distance from the stirred axis. The radionuclides 241Am and 137Cs were used as radiation sources. (author)

  7. Investigation of breakage behavior of coal in a laboratory-scale stirred media mill

    Energy Technology Data Exchange (ETDEWEB)

    Samanli, S.; Cuhadaroglu, D.; Ucbas, Y.; Ipek, H. [Zonguldak Karaelmas University, Zonguldak (Turkey). Mining Engineering Department

    2010-07-01

    Coal obtained from the Catalagzi thermal power station was prepared into a -2360 +1700 {mu}m mono size fraction and ground for different times in a laboratory-scale stirred media mill. The breakage behavior was investigated and an attempt was made to determine optimum grinding conditions. Three stirring rates (1440, 720, and 360rpm) and three ball sizes (6, 4, 2.36mm) were utilized in the grinding studies. It was determined that for effective grinding not only the mill's mechanical properties but also the material properties have to be taken into consideration in order to determine breakage functions more accurately. At longer grind times, oversize material mainly composed of shale, which is comparatively difficult to grind. As a result of this, breakage rate slows down and a deviation from first-order breakage behavior occurs in the grinding stage.

  8. Improved coal grinding and fuel flow control in thermal power plants

    DEFF Research Database (Denmark)

    Niemczyk, Piotr; Bendtsen, Jan Dimon

    2011-01-01

    A novel controller for coal circulation and pulverized coal flow in a coal mill is proposed. The design is based on optimal control theory for bilinear systems with additional integral action. The states are estimated from the grinding power consumption and the amount of coal accumulated in the mill by employing a special variant of a Luenberger observer. The controller uses the rotating classifier to improve the dynamical performance of the overall system. The proposed controller is compared with a PID-type controller with available pulverized coal flow measurements under nominal conditions as well as when parameter uncertainties and noise are present. The proposed controller lowers the grinding power consumption while in most cases exhibiting superior performance in comparison with the PID controller.

  9. Prediction of work-roll temperature distribution in continuous hot strip rolling process

    International Nuclear Information System (INIS)

    Prediction of temperature distribution within the work-rolls during the hot slab rolling process is of great importance to mill designers. This is because, not only the temperature distribution in rolling material and the dimensional accuracy are depended on work-roll temperature but also the roll life is a function of its temperature distribution. In this paper using the heat transfer equations for moving media and a two dimensional finite element method, the work-roll temperature distribution during continuous hot strip rolling process is predicted. To achieve an accurate temperature field the effects of various factors including the rolling speed, interface heat transfer coefficient, and the amount of slab thickness reduction at each deformation pass are taken into account. Comparison between the predicted and experimental published results depicts the validity of the mathematical model. (author)

  10. Grinding induced martensite on the surface of rails

    DEFF Research Database (Denmark)

    Rasmussen, C.J.; Zhang, Xiaodan

    2014-01-01

    Rolling contact fatigue (RCF) is causing crack initiation and crack propagation in rails. Some types of RCF cracks are found to be associated with a white etching layer (WEL). A metallurgical investigation was carried out on a worn rail and the amounts of WEL at different positions on the rail were determined. Two different rail types R260 and R350HT that both had been ground by a grinding train were investigated. The rail sections, studied using optical and scanning electron microscopy, showed that the surface of both types of rails is covered with WELs. The hardness of the WEL is increased compared to the base material and the microstructural investigations reveal that a martensitic structure is present at the surface.

  11. Progress in abrasive and grinding technology

    CERN Document Server

    Xu, Xipeng

    2009-01-01

    The grinding and abrasive processing of materials are machining techniques which use bonded or loose abrasives to remove material from workpieces. Due to the well-known advantages of grinding and abrasive processes, advances in abrasive and grinding technology are always of great import in enhancing both productivity and component quality. In order to highlight the recent progress made in this field, the editor invited 21 world-wide contributions with the aim of gathering together all of the achievements of leading researchers into a single publication. The authors of the 21 invited papers, of

  12. Theoretical considerations of machining with grinding wheels

    OpenAIRE

    Andrew Oyakhobo Odior; Oyawale, Festus A.; Oyedepo, Sunday O.; Aasa, Samson A.

    2013-01-01

    Grinding is one of the most versatile methods of removing material from machine parts by the cutting action of the countless hard and sharp abrasive particles of a revolving grinding wheel. It works by forcing the abrasive grains into the surface of the workpiece so that each grain cuts away a small bit of material in the form of chips. Abrasive grinding wheel is an expendable wheel that carries an abrasive compound on its periphery. They are made of small, sharp and very hard natural or synt...

  13. Rolling Reloaded

    Science.gov (United States)

    Jones, Simon A.; Nieminen, John M.

    2008-01-01

    Not so long ago a new observation about rolling motion was described: for a rolling wheel, there is a set of points with instantaneous velocities directed at or away from the centre of the wheel; these points form a circle whose diameter connects the centre of the wheel to the wheel's point of contact with the ground (Sharma 1996 "Eur. J. Phys."…

  14. Failure Analysis of Rollers in mill stand using Failure mode Effect Analysis

    OpenAIRE

    Tadisetti Premsai; Anga Kiran Vikram; Varma, S.Sivarajan

    2014-01-01

    Rolling is an important steel production process. Productivity and quality improvements in metal rolling are possible by paying a detailed attention to the various roll failure modes.A proper understanding of the causes of roll failure modes is usually complex and depends on the metallurgical quality of rolls, improper mill usage practices and abnormal rolling conditions. The work rolls operate under severe condition and should posses excellent wear resistance and very little ...

  15. Influence of the charge properties on the milling tools wear during intensive milling in liquid environment

    Directory of Open Access Journals (Sweden)

    Števulová Nadežda

    2002-06-01

    Full Text Available Grinding belongs to the basic technological operations in the treatment and processing of minerals. The method of the intensive grinding in a liquid environment has become attractive for the preparation of technologically advanced materials of the high fineness. Its choice was motivated by the intensification of dispersion and by the protection of ground powder against oxidation. The result of energy and material interactions among the grinding media and grinding environment is the wear of the grinding media and contamination of the ground material. The hardness of the particles has an important influence on the rate of wear. Particles with hardness lower than that of the surface of milling tools cause much less wear than harder particles. The wear rate becomes much more sensitive to the ratio of the abrasive hardness Ha to the surface hardness Hs when Ha/Hs <¡­1.The paper deals with the influence of four minerals with various microhardness (corundum, quartz, silicon and magnesite on the steel milling tools wear during intensive milling.. Experiments were performed in a vibration mill in methanol under same conditions. The grinding time was changed in a geometric sequence from 0,125 to 4 hours. The newly created surface area providesa basic information on grinding. The specific surface area was determined by the standard Brunauer-Emmett-Teller (BET method using the appratus Gemini 2360 (Sylab, Austria. The concentration of iron was determined by AAS (SpectrAA-30, Varian, Australia. It was confirmed that the rate of ball wear depends on the hardness of feed materials. It was found that the relation between the contamination of the ground powders by wear and the specific surface area increment is linear and the slope depends on the microhardness of the ground material.

  16. The analysis of the asymmetric plate rolling process

    OpenAIRE

    Kawa?ek, A.

    2007-01-01

    Purpose: The analysis of asymmetric band rolling in the finishing stand of a plate rolling mill has been carried out within the present study with the aim of establishing the effect of the speed asymmetry factor, av, on band bending during the rolling process and determining the strain velocity distributions of the rolled material in the roll bite region.Design/methodology/approach: The simulation of metal flow in the asymmetric roll bite region was performed using the program FORGE 2D. The d...

  17. Uranium milling at Bear Creek

    International Nuclear Information System (INIS)

    The Bear Creek uranium project is located in the southern Powder River basin in Wyoming. The mine is an open pit; the ore occurs in poorly consolidated sandstone that is typically coarse- to fine-grained. The ore minerals are mainly uraninite and coffinite. The current mill sustains feed rates of 2400 tpd with plant availability of 98 percent and recovery rates of 97 percent. Processing includes grinding, leaching, washing (treating sands and slimes separately), clarification, solvent extraction, precipitation, and drying

  18. Impact pressure of water in hydraulic descaling during hot strip mill rolling. Netsukan atsuen ni okeru koatsusui datsu scale ji no shototsu atsu

    Energy Technology Data Exchange (ETDEWEB)

    Wada, T.; Oshimi, M. (Nippon Steel Corp., Tokyo (Japan)); Ueda, M. (Hotani Co. Ltd., Osaka (Japan))

    1991-09-01

    Using white Plasticine which shows plastic deformation similar to that of high temperature steel materials, the decrease in the thickness by high pressure water is measured, and impact pressure of water at the time of high pressure water injection is measured with a pressure converter to formulate the relationship with various factors. The thickness loss of Plasticine at the time of high pressure injection is closely correlated with 4 parameters, i.e. water consumption, water pressure, rolling speed, and vertical distance. The thickness loss and impact pressure by hydraulic descaling can be expressed by empirical formulas of {Delta}t = 2000 PV (vH{sup 2}) (cm, correlation coefficient: 0.94) and p = 5.64 PV H{sup 2} (MPa). The impact pressure equation is simple and practical, and agrees well with the result obtained by the equation of Hojas et al. The impact pressure required to remove the primary scale is much higher than that required for the secondary scale, and a careful set up of the conditions is essential to complete the descaling. 13 refs., 7 figs., 7 tabs.

  19. The grinding of uranium dioxide from fluidized beds

    International Nuclear Information System (INIS)

    This work deals with the UO2 vibratory grinding, the UO2 obtained from fluidized beds. In this study the grinding time has been correlated with surface area, stoichiometry, granulometry and grinded product contamination. The efficiency losses in the grinding of moisten UO2 are outlined. Finally it is made a brief study of the granulate obtained from the grinded UO2 as well as the green pellets resulting from it, taking into consideration the dispersion of its density and height. (Author)

  20. Tallinnas on kõne all spordi muutuv roll kõrghariduses / Raivo Russmann, Malle Jürves

    Index Scriptorium Estoniae

    Russmann, Raivo

    2006-01-01

    Tallinna Tehnikakõrgkooli korraldusel toimub 8.-12. novembrini Tallinnas 9. üle-euroopalise kõrgkoolide spordikeskuste assotsiatsiooni ENAS konverents, mille teemaks on spordi muutuv roll kõrghariduses

  1. Modelling of dynamic contact length in rail grinding process

    Science.gov (United States)

    Zhi, Shaodan; Li, Jianyong; Zarembski, A. M.

    2014-09-01

    Rails endure frequent dynamic loads from the passing trains for supporting trains and guiding wheels. The accumulated stress concentrations will cause the plastic deformation of rail towards generating corrugations, contact fatigue cracks and also other defects, resulting in more dangerous status even the derailment risks. So the rail grinding technology has been invented with rotating grinding stones pressed on the rail with defects removal. Such rail grinding works are directed by experiences rather than scientifically guidance, lacking of flexible and scientific operating methods. With grinding control unit holding the grinding stones, the rail grinding process has the characteristics not only the surface grinding but also the running railway vehicles. First of all, it's important to analyze the contact length between the grinding stone and the rail, because the contact length is a critical parameter to measure the grinding capabilities of stones. Moreover, it's needed to build up models of railway vehicle unit bonded with the grinding stone to represent the rail grinding car. Therefore the theoretical model for contact length is developed based on the geometrical analysis. And the calculating models are improved considering the grinding car's dynamic behaviors during the grinding process. Eventually, results are obtained based on the models by taking both the operation parameters and the structure parameters into the calculation, which are suitable for revealing the process of rail grinding by combining the grinding mechanism and the railway vehicle systems.

  2. The analysis of the asymmetric plate rolling process

    Directory of Open Access Journals (Sweden)

    A. Kawa?ek

    2007-08-01

    Full Text Available Purpose: The analysis of asymmetric band rolling in the finishing stand of a plate rolling mill has been carried out within the present study with the aim of establishing the effect of the speed asymmetry factor, av, on band bending during the rolling process and determining the strain velocity distributions of the rolled material in the roll bite region.Design/methodology/approach: The simulation of metal flow in the asymmetric roll bite region was performed using the program FORGE 2D. The development of numerous branches of the steelmaking industry imposes increasingly high demands on steel product manufacturers, which can only be met by products manufactured according to the state-of-the-art plastic working technologies. One of the major plastic working technologies is asymmetric rolling.Findings: The analysis shows that the band bends most often toward the lower-speed roll. Increasing the value of the speed asymmetry factor causes an increase in the advance, while the force parameters decrease with increasing asymmetry factor av.Practical implications: Asymmetric rolling is achieved by differentiating working roll diameters, roll rotational speeds, or roll surface roughness. In industrial practice, one or a combination of the above-mentioned parameters is used.Originality/value: In order to improve the asymmetric plate rolling process, the analysis of the following parameters must be carried out: band temperature, the magnitude of rolling reduction, the magnitude of yield stress for particular steel grades, roll rotational speeds and roll diameters.

  3. Preparation and Characterization of Co-Grinded Mixtures of Aceclofenac and Neusilin US2 for Dissolution Enhancement of Aceclofenac

    OpenAIRE

    Vadher, Ambarish H.; Parikh, Jolly R.; Parikh, Rajesh H.; Solanki, Ajay B.

    2009-01-01

    The present study was carried out with a view to enhance the dissolution of poorly water-soluble BCS-class II drug aceclofenac by co-grinding with novel porous carrier Neusilin US2. (amorphous microporous granules of magnesium aluminosilicate, Fuji Chemical Industry, Toyama, Japan). Neusilin US2 has been used as an important pharmaceutical excipient for solubility enhancement. Co-grinding of aceclofenac with Neusilin US2 in a ratio of 1:5 was carried out by ball milling for 20 h. Samples of ...

  4. Mechanical alloying and reactive milling in a high energy planetary mill

    International Nuclear Information System (INIS)

    Powder refinement in a planetary mill (Retsch PM 400-MA) is investigated experimentally and analyzed using discrete element modeling (DEM). Refinement is defined as the average size of the individual components in a composite powder. The specific milling dose, defined as the product of charge ratio and milling time, is used as an experimental parameter tracking the progress of the material refinement. This parameter is determined experimentally for milling of boron and titanium powders, for which the time of initiation of a self-sustained reaction is measured under different milling conditions. It is assumed that the reaction becomes self-sustaining when the same powder refinement is achieved. The DEM calculations established that the milling balls primarily roll along the milling container's perimeter. The inverse of the rate of energy dissipation resulting from this rolling motion is used as the DEM analog of the specific milling dose. The results correlate well with experimental observations.

  5. The significance of grinding environment on the flotation of UG2 ores

    Scientific Electronic Library Online (English)

    C.J., Greet.

    2009-01-01

    Full Text Available A large body of work exists discussing the impact of grinding media on mineral flotation. Generally, the work indicates that a change to a less electrochemically active grinding environment has positive benefits on downstream processing. There is a fear, however, that these benefits may not be reali [...] zed when treating low sulphide containing ores, typified by UG2 style deposits. A series of experiments was developed to test the flotation response of UG2 ores using the Magotteaux Mill® to determine if measurable differences in the pulp chemistry could be discerned using a range of grinding media types. Further, the flotation responses of the contained sulphides (chalcopyrite, pentlandite and pyrrhotite) were determined. The data collected provided strong evidence that the grinding environment can significantly influence the pulp chemistry and flotation characteristics of all sulphide minerals, even when the ore contains less than 0.5 per cent total sulphide. The results show that the change to an inert media type produced a substantial improvement in the flotation rate of all sulphide minerals, as well as the PGMs.

  6. Using of fluidized-bed jet mill to a super fine comminution of steel composite

    Directory of Open Access Journals (Sweden)

    D. Urbaniak

    2015-01-01

    Full Text Available In many industries the demand for very fine material increases. In the metallurgical industry, for example, there is increasing use of the production of high density metal elements with the use of metallurgical powder composites. The use of powder composites requires prior their grinding. Unfortunately, the very fine grinding is not an easy process. The using for this purpose fluidized-bed jet mill was proposed in the paper. The attempts of grinding of metallurgical powder were carried out in the fluidized-bed jet mill. After the experiment analyses of particle size distribution of grinding products were performed. The results are presented in graphs. Analyses of the obtained results concluded that the grinding of very fine metallurgical composite is possible and produces positive results.

  7. Effect of ball milling materials and methods on powder processing of Bi2223 superconductors

    International Nuclear Information System (INIS)

    Various milling systems consisting of agate and polypropylene grinding containers, agate and YSZ balls, and dry and wet milling were used in planetary ball-milling and YSZ balls and YSZ container were used in wet and dry attrition milling. The differently milled powders were then evaluated by measurements of particle size, surface area, porosity, size distribution and chemical analysis of the Si, Zr and C contents. The results show that dry milling is much more efficient for particle size reduction in planetary milling than wet milling, whereas wet milling and dry milling gave quite similar results in attrition milling. Meanwhile SiO2 contamination was found in powder milled with an agate container with agate balls. Some C contamination from the polypropylene container was detected after milling, but negligible Zr from YSZ balls and C from the grinding carrier (hexane). It was found that after 1 h milling in the planetary mill fracture mechanisms transform from the elastic to the plastic region. Therefore, further milling is not very effective. It was also shown that the Bi2212 phase decomposes into several non-superconducting oxides such as Ca2PbO4, (Sr, Ca)2CuO3, CuO and a main amorphous phase after extensive dry milling. (author)

  8. High-energy milling as a method for obtaining tetragonal form of PbO

    OpenAIRE

    M. Staszewski; Z. Myczkowski; K. Bilewska; R. Sosi?ski; Lis, M.; M. Czepelak; D. Ko?acz

    2012-01-01

    Purpose: The aim of this work was to verify the usefulness of high-energy milling, using electromagnetic mill, as a method for obtaining tetragonal (red) form of PbO, alternative to standard methods.Design/methodology/approach: Experiments were held to compare samples of the yellow form of PbO after milling in electromagnetic mill with the ones milled in high-energy planetary ball mill as a function of grinding medium (sticks or balls) to powder mass ratio, milling duration and instrumental c...

  9. Modeling of the process of coal grinding

    OpenAIRE

    T. Wylecia?; H. Radomiak; D. Urbaniak

    2013-01-01

    The use of coal in the steel industry, similarly as in the whole national economy, is often preceded by its pre-treatment. Coal is mined in the form of big solids, but, being in such a form, it can’t be combusted, sintered, or gasified. Therefore, it needs to be appropriately grinding. In the paper results of the numerical prediction of the grain size distribution of the grinding coals are presented. The numerical computations were performed and then they were compared with grain size analysi...

  10. Modeling of the process of coal grinding

    Directory of Open Access Journals (Sweden)

    T. Wylecia?

    2013-04-01

    Full Text Available The use of coal in the steel industry, similarly as in the whole national economy, is often preceded by its pre-treatment. Coal is mined in the form of big solids, but, being in such a form, it can’t be combusted, sintered, or gasified. Therefore, it needs to be appropriately grinding. In the paper results of the numerical prediction of the grain size distribution of the grinding coals are presented. The numerical computations were performed and then they were compared with grain size analysis results.

  11. Mill’s Perfectionism

    Directory of Open Access Journals (Sweden)

    PIERGIORGIO DONATELLI

    2006-12-01

    Full Text Available J. S. Mill lays great emphasis on the importance of the notion of theindividual as a progressive being. The idea that we need to conceive the self as an object of cultivation and perfection runs through Mill’s writings on various topics, and has played a certain role in recent interpretations. In this paper I propose a specific interpretation of Mill’s understanding of the self, along the lines of what Stanley Cavell identifies as a “perfectionist” concern for the self. Various texts by Mill, ranging from the Logic to On Liberty, show an understanding of the self in which both the theoretical and the practical domain are presented as being internally connected to the transformation of the self. Mill elaborates a criticism of a notion of truth articulated by doctrines having a life independent of the self, as well as a notion of choice which is not the expression of one’s inner self. This internal relation of truth and choice to the self generates a special dialectic within the self, which Mill explores in On Liberty’s second and third chapters by means of several contrasts, such as passive vs. active knowledge, living vs. dead beliefs, or being oneself vs. liking and choosing in crowds.

  12. Delamination of hexagonal boron nitride in a stirred media mill

    Energy Technology Data Exchange (ETDEWEB)

    Damm, C., E-mail: cornelia.damm@fau.de; Koerner, J.; Peukert, W., E-mail: Wolfgang.Peukert@lfg.fau.de [University Erlangen-Nuremberg, Institute of Particle Technology (Germany)

    2013-04-15

    A scalable process for delamination of hexagonal boron nitride in an aqueous solution of the non-ionic surfactant TWEEN85 using a stirred media mill is presented. The size of the ZrO{sub 2} beads used as grinding media governs the dimensions of the ground boron nitride particles as atomic force microscopic investigations (AFM) reveal: the mean flakes thickness decreases from 3.5 to 1.5 nm and the ratio between mean flake area and mean flake thickness increases from 2,200 to 5,800 nm if the grinding media size is reduced from 0.8 to 0.1 mm. This result shows that a high number of stress events in combination with low stress energy (small grinding media) facilitate delamination of the layered material whereas at high stress energies in combination with a low number of stress events (large grinding media) breakage of the layers dominates over delamination. The results of particle height analyses by AFM show that few-layer structures have been formed by stirred media milling. This result is in agreement with the layer thickness dependence of the delamination energy for hexagonal boron nitride. The concentration of nanoparticles remaining dispersed after centrifugation of the ground suspension increases with grinding time and with decreasing grinding media size. After 5 h of grinding using 0.1 mm ZrO{sub 2} grinding media the yield of nanoparticle formation is about 5 wt%. The nanoparticles exhibit the typical Raman peak for hexagonal boron nitride at 1,366 cm{sup -1} showing that the in-plane order in the milled platelets is remained.

  13. Delamination of hexagonal boron nitride in a stirred media mill

    International Nuclear Information System (INIS)

    A scalable process for delamination of hexagonal boron nitride in an aqueous solution of the non-ionic surfactant TWEEN85 using a stirred media mill is presented. The size of the ZrO2 beads used as grinding media governs the dimensions of the ground boron nitride particles as atomic force microscopic investigations (AFM) reveal: the mean flakes thickness decreases from 3.5 to 1.5 nm and the ratio between mean flake area and mean flake thickness increases from 2,200 to 5,800 nm if the grinding media size is reduced from 0.8 to 0.1 mm. This result shows that a high number of stress events in combination with low stress energy (small grinding media) facilitate delamination of the layered material whereas at high stress energies in combination with a low number of stress events (large grinding media) breakage of the layers dominates over delamination. The results of particle height analyses by AFM show that few-layer structures have been formed by stirred media milling. This result is in agreement with the layer thickness dependence of the delamination energy for hexagonal boron nitride. The concentration of nanoparticles remaining dispersed after centrifugation of the ground suspension increases with grinding time and with decreasing grinding media size. After 5 h of grinding using 0.1 mm ZrO2 grinding media the yield of nanoparticle formation is about 5 wt%. The nanoparticles exhibit the typical Raman peak for hexagonal boron nitride at 1,366 cm?1 showing that the in-plane order in the milled platelets is remained.

  14. Rolling Returns

    Science.gov (United States)

    Fresno Community Science Workshop

    2012-01-01

    In this activity, learners build a special rolling can that returns back to you when you push it forward. Use this activity to demonstrate the transfer of energy between kinetic and potential energy. Note: a drill is used in this activity, and is not included in the cost of materials.

  15. Critical review of Nanofluid Minimum Quantity Lubrication for Grinding application

    Directory of Open Access Journals (Sweden)

    Mr. Prashant J. Patil,

    2014-08-01

    Full Text Available In recent years, the environment has become one of the most important subject. Emulsion-based cooling fluids are used in grinding for a variety of reasons such as improving surface finish, wheel life, flushing away chips, reducing workpiece thermal deformation. Due to large fluid delivery an extensive amount of mist is generated during grinding process. The workers who breathe in this hazardous mist is having health hazard. There are two alternative for large cutting fluids. One is dry grinding and another is near dry grinding also known as minimum quantity lubrication. MQL grinding refers to the delivery of minute quantity of fluid via an aerosol to the grinding zone. The typical flow rate of grinding fluid for MQL fluid consumption is generally 20-100 ml/hour. Although numerous advantages were found for MQL grinding compared with the conventional technique and dry grinding. The cooling and lubrication performance of the grinding fluid is the key technical area for the success application of MQL grinding process. Nanofluid has emerged as a promising solution to this problem. Nanofluid is a new class of fluids engineered by dispersing nanometer-size solid particles into base fluids such as water, lubrication oils. The excellent properties of the nanofluid makes very attractive in cooling and lubricating application in manufacturing. . This study provides a review of research in this field with focus on use of nanofluids in grinding applications.

  16. Quality assessment of rolled strip produced by compact versus conventional rolling

    International Nuclear Information System (INIS)

    In continuous casting and rolling, the major factors that influence the quality are frequently interrelated and dependent on each other, with complex confluent relationships. When one of these factors changes, e.g. the temperature, not only is the rolling force affected, but the torque and surface properties, as kinematic boundary conditions, changes as well. The same is valid for the geometric quality parameters, consisting of thickness, profile, flatness, width and wedge, as well as for surface roughness. In order to be able to predict and improve the expected quality of the rolled sheet, detailed analysis of all these factors is necessary. The steel quality-producing of the new compact strip production technique as compared to as an integrated mill is studied by using modern data mining tools, primarily the Self-Organizing Map (SOM) approach. The data are gathered at several steel mills. In this paper data from two mills is analyzed using a bench marking approach. (author)

  17. Rolls-Royce implementing new production system

    Science.gov (United States)

    1982-05-01

    An advanced, integrated manufacturing systems system is being implemented in Rolls-Royce production facilities in order to cut unit production costs by reducing lead times, manning levels and inventories. The topics discussed include the program outline, planned subcontracting, the machining operation that includes isothermal forming of wide-chord hollow blades, carbon fiber production of subsystems including thrust reversers, continuous dress creep feed grinding, the directionally solidified casting facility that can produce single-crystal blades without modification to the casting furnaces, and a robot machining line.

  18. Mathematical Aspect for Worm Grinding Using a Toroidal Tool

    Directory of Open Access Journals (Sweden)

    Tareq A. Abu Shreehah

    2004-01-01

    Full Text Available This paper is an attempt to improve the accuracy of the worm gearings with concave profile of the worm thread by using a new generating surface of grinding wheel to eliminate the lacks of the popular worm gearings and extensioning the field of investigation. The present study propose grind concave profile worms by means of toroidal tool - grinding wheel which section in the axial plane is an arc of parabola. The generating equation of the grinding wheel surface and the arrangement of this wheel with respect to the worm during grinding of its thread was determined.

  19. The Effect of Cutting Speed in Metallic Glass Grinding

    International Nuclear Information System (INIS)

    In this paper, the effects of the cutting speed in metallic glass grinding were investigated in dry conditions. The results showed that grinding forces decrease as grinding energy increase with the increasing cutting speeds. The present investigations on ground surface and grinding chips morphologies -shows that material removal and surface formation of the BMG are mainly due to the ductile chip deformation and ploughing as well as brittle fracture of some particles from the edges of the tracks. The roughness values obtained with the Cubic Boron Nitride wheels are acceptable for the grinding operation.

  20. Kommunikatsiooni roll kiirelt muutuvas maailmas / Susan Lilleväli, Marit Priks

    Index Scriptorium Estoniae

    Lilleväli, Susan

    2014-01-01

    Tartu Ülikooli akadeemilise kommunikatsiooni klubi kolmandast kohtumisest, mille teemaks oli "Kuidas hallata komplekssust?". Tartu Ülikooli doktorant Regina Salmu tutvustas oma uurimistööd, mille keskmes on innovaatiliste teenuste arendusprotsessid ning kommunikatsiooni roll selles. Teises töörühmas arutati erinevatest kanalitest sissetuleva info kvaliteedi ja publitseeritavuse üle otsustamisest ajakirjandusväljaannete toimetuste töös

  1. High pressure grinding moving ahead in copper, iron, and gold processing

    Scientific Electronic Library Online (English)

    F.P., van der Meer; W., Maphosa.

    2012-07-01

    Full Text Available High pressure grinding roll (HPGR) technology is used in an increasingly diverse range of applications, predominantly iron ore , gold and diamonds. KHD Humboldt Wedag HPGRs are applied world-wide, and consistently prove to be well designed and reliable operating units, with their performance meeting [...] the pre-set standards. This publication summarizes some of the features and experiences for recent applications in treatment of copper ore, coarse iron ore, and gold ore. Summary data of roll surface wear life and operating data are given, together with operational observations. In addition, effects of feed segregation and truncated feed are discussed, as well as the implications of a product recycle flow sheet.

  2. Studying possibilities to improve the functional properties of metallurgical rolls

    OpenAIRE

    Z. Stradomski; A. Pirek; S. Stachura

    2008-01-01

    Thc paper prcscnts rcsults nT invcst igations and at~thors' opinion on improving functional propcrtics of mciall urgicnl rolls cast fromGZOOCrMoNi 4-9-3 cast wccl. onc nf most oftcn ilscd lor rolls in scction mills. Thcsc mills Icn~urcq uickcr than flat rolls wear or 1001'spass. whar rcquircs morc Crcqocnt rcpcncr;lt ion. 'Thc machining rcquircs n rclat ivcly low hardness, which is cnsurcd hy ~ h pcc arliiic matrixof casr steel strldid. 7 % ~au thors silggcst 10 achicvc thc optimisntion o f t...

  3. Optimal sizing, scheduling and shift policy of the grinding section of a ceramic tile plant

    OpenAIRE

    Duarte, Belmiro P. M.; Santos, Lino O.; Mariano, Jorge S.

    2008-01-01

    This paper addresses the optimal design of the grinding section of a ceramic tile plant operating in a cyclic mode with the units (mills) following a batch sequence. The optimal design problem of this single product plant is formulated with a fixed time horizon of one week, corresponding to one cycle of production, and using a discrete-time resource task network (RTN) process representation. The size of the individual units is restricted to discrete values, and the plant operates with a set o...

  4. Optimisation of grinding parameters for preparation of coal-water mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Besra, L.; Panda, D.; Parida, A. [Regional Research Laboratory, Bhubaneswar (India)

    1995-12-31

    Coal-water mixture (CWM) has attracted attention as a substitute for fuel oil and as a more convenient and economical form of coal for transportation and end use. In the present investigation studies on grinding characteristics of a high ash content coal has been carried out in a laboratory ball mill to ascertain breakage parameters. The rheological tests have been conducted in a Haake viscometer and it is found that both pseudoplastic and Bingham behaviour is observed depending on coal types and concentrations. The breakage at low solid concentration is usually first order, but slowing down of breakage occurs with increase in solid concentration. 4 refs., 7 figs., 2 tabs.

  5. Grinding behavior of silicon wafer and sintered Al2O3 by constant-force-feeding grinding system

    International Nuclear Information System (INIS)

    Excessive forces acting on grinding surfaces cause defects on specimen during grinding. Removal depth and table feeding rate are the only controlling factors for a conventional grinding system. A new grinding system is proposed modifying the feeding process to maintain feeding force constant instead of feeding rate. Forces of a grinding wheel on a specimen are easily controlled by the present method. We used 4 inch Si wafer and sintered Al2O3 (25 mm X 50 mm) to evaluate grinding forces, table-feeding rate for a given feeding force and ground defects. We found that the forces to grind sintered Al2O3 and Si wafers behave in different way. The table-feeding rate decreases as feeding depth increases. Estimating the energy required to remove a given volume of specimen, i. e., specific grinding energy, shows a constant curve for any given feeding depth. Surface roughness was evaluated by confocal laser microscopy, and did not change for different amounts of feeding depth from 1 ?m to 50 ?m. Finally, we could grind the silicon wafer from 0.5 mm thickness to 40 ?m and the sintered-Al2O3 from 1 mm thickness to 40 ?m by only one-step of grinding in less than 50 min. We found that the constant grinding force system allow to minimize defects. Copyright (2003) AD-TECH - International Foundation for the Advancement of Technology Ltd

  6. Non Circular Arc Temper Rolling Model Considering Radial And Circumferential Work Roll Displacements

    Science.gov (United States)

    Krimpelstätter, Konrad; Zeman, Klaus; Kainz, Alexander

    2004-06-01

    Compared to usual cold rolling conditions the length of contact between work roll and strip is very short in case of temper rolling. As a consequence, work roll flattening becomes critical even for small contact pressures, and the simplifying assumption of a "circular arc" contour of the deformed work roll cannot be justified anymore. A new temper rolling model is presented applying a non circular arc theory using a semi-analytical procedure for the calculation of the elastic work roll deformations based on numerical superposition of influence functions. In addition to the radial displacements of the work roll, also the circumferential displacements, generated mainly by the shear stresses acting on the work roll surface, are taken into account. The circumferential displacements heavily affect the relative speed (slip speed) between the surfaces of work roll and strip, this speed being a crucial input parameter for any friction law. Hence, the evolution of the shear stresses in the roll gap is re-affected by these circumferential displacements. Their influence is increasing with decreasing temper degrees and cannot be neglected in such cases. The formation of a neutral zone instead of a neutral point is a natural consequence of this approach. The model for the strip is based on Karman's theory. In addition to the elastic compression-, elastic recovery- and plastic zone, also elastic regions are allowed to arise between plastic zones (Internal Elastic Zones). The consequence is that the case of contained plastic flow will appear automatically without additional simplifying assumptions. Simulation results from the new model are presented and discussed. Their comparison with results from FE-simulations shows very good agreement. The model was calibrated against practical data from an existing temper rolling mill. For this purpose extensive temper rolling tests were performed.

  7. A reliability analysis for the grinding process

    OpenAIRE

    Tolvanen, Pekka

    2011-01-01

    This Bachelor’s thesis was made in collaboration with the Service Product Center Espoo of Outotec (Finland) Oy during the spring semester 2011. The main objectives of this thesis were to create a reliability analysis of the mineral enrichment process grinding circuit and to examine the possibilities for the analysis as a company’s new service product. The scope for this thesis was limited by the mandator. As the machinery of the process industry is getting older, the role of maintenance ...

  8. Vibration syndrome and vibration in pedestal grinding.

    OpenAIRE

    Starck, J.; Fa?rkkila?, M.; Aatola, S.; Pyykko?, I.; Korhonen, O.

    1983-01-01

    At one Finnish foundry all the workers had typical symptoms of vibration induced white finger (VWF) after they began using a new type of pedestal grinding machine. The objectives of this study were to establish the severity of the symptoms and the difference in vibration exposure between the new and the old machines. Vibration detection thresholds and grip forces were measured, as well as the vibration in the casting and in the wrist simultaneously. The mean latency for VWF among the grinders...

  9. Production of talc nano sheets via fine grinding and sonication processes

    International Nuclear Information System (INIS)

    Fine grinding of high purity talc in jet mill at low grinding pressure was carried out by varying the feed rate and classifier rotational speed. These ground particles were sonicated in laboratory ultrasonic bath by varying the soniction period at five levels. The ground and sonicated particles were characterized in terms of particle size and particle size distribution. Mechanochemical and sonochemical effect of talc was determine via X-ray diffraction. Particle shape and surface texture of the ground and sonicated product was determined via scanning electron microscope and transmission electron microscope. The ground particle size exhibited particle size below 10 ?m with narrow size distribution. The reduction of peak intensity in (002) plane indicated the layered structure has been distorted. The sonicated talc shows that the thickness of the talc particles after the sonication process is 20 nm but the lateral particle size still remains in micron range. The reduction of the XRD peak intensity for (002) plane and thickness of sonicated talc as shown in SEM and TEM micrographs proves that fine grinding and sonication process produces talc nano sheets. (author)

  10. Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material

    OpenAIRE

    M. Drobne; Vuherer, T.; I. Samardži?; S Glodež

    2014-01-01

    Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for roll’s shell material. To obtain corresponding parameters, a rectangular single edge notched bend specimens – SENB, according to standard BS 7448, were used. The fatigue crack growth analysis was done on a resonant testing machine with use of special crack gauges, while for fracture...

  11. Evaluation of temperature field and heat flux by inverse analysis during steel strip rolling

    OpenAIRE

    Weisz-patrault, Daniel; Ehrlacher, Alain; Legrand, Nicolas

    2012-01-01

    Knowledge of the temperature field in the roll is a critical factor of modern, high-speed rolling mills. In this paper, an inverse analytical method is developed to determine the temperature field and especially the temperature (and heat flux) at the surface of the roll by measuring the temperature with a thermocouple (fully embedded) at only one point inside the roll. Iterative methods are not studied because short computation times are desired. Some assumptions are done to resolve analytica...

  12. Study of texture, microstructure and mechanical properties of asymmetrically rolled aluminium

    Science.gov (United States)

    Wronski, M.; Wierzbanowski, K.; Wronski, S.; Bacroix, B.; Wróbel, M.; Uniwersa?, A.

    2015-04-01

    Asymmetric rolling is a promising forming technique offering numerous possibilities of material properties modification and the improvement of technological process parameters. This geometry of deformation is relatively easy to implement on existing industrial rolling mills. Moreover, it can provide large volume of a material with modified properties. The study of microstructure, crystallographic texture and mechanical properties of asymmetrically rolled aluminium is presented in this work. The above characteristics were examined using EBSD technique and X-ray diffraction. The rolling asymmetry was realized using two identical rolls, driven by independent motors, rotating with different angular velocities. It was found that asymmetric rolling leads to microstructure refinement, texture homogenization and decreasing of residual stress.

  13. Energy requirement for fine grinding of torrefied wood

    OpenAIRE

    Repellin, Vincent; Govin, Alexandre; Rolland, Mathieu; Guyonnet, René

    2010-01-01

    The purpose of this study is to investigate the influence of torrefaction on wood grinding energy. Wood chips were torrefied at different temperatures and durations. The energy required to obtain fine powder was measured. Particle size analyses were carried out on each powder sample. It is showed that torrefaction decreases both grinding energy and particle size distribution. A criterion to compare grindability of natural and torrefied wood is proposed. It takes into account both grinding ene...

  14. The effect of dry grinding on antigorite from Mulhacen, Spain

    OpenAIRE

    Drief, A.; Nieto, F.

    1999-01-01

    Alteration of the crystal structure of Mulhacén antigorite caused by dry, vibration grinding was investigated by X-ray diffraction (XRD), infrared spectroscopy (IR), thermal analyses (TG), grainsize distribution, and transmission and analytical electron microscopy (TEM, AEM). Grinding for 1 min reduces particles to a size ideal for IR and TG. With prolonged grinding, XRD and electron diffraction patterns showed that the crystal structure was affected mainly along the c axis, caus...

  15. Grinding tool for making hemispherical bores in hard materials

    Science.gov (United States)

    Duran, E.L.

    1985-04-03

    A grinding tool for forming hemispherical bores in hard materials such as boron carbide. The tool comprises a hemicircular grinding bit, formed of a metal bond diamond matrix, which is mounted transversely on one end of a tubular tool shaft. The bit includes a spherically curved outer edge surface which is the active grinding surface of the tool. Two coolant fluid ports on opposite sides of the bit enable introduction of coolant fluid through the bore of the tool shaft so as to be emitted adjacent the opposite sides of the grinding bit, thereby providing optimum cooling of both the workpiece and the bit.

  16. a Traffic-Dependent Acoustical Grinding Criterion

    Science.gov (United States)

    DINGS, P.; VERHEIJEN, E.; KOOTWIJK-DAMMAN, C.

    2000-03-01

    On most lines of the Dutch railway network, where a substantial amount of block-braked trains have rough wheels, the average wheel roughness dominates over the rail roughness. Therefore, reducing wheel roughness is top priority in the Netherlands. However, for the situations where rail roughness exceeds wheel roughness, this roughness can be lowered at acceptable cost. The high rail roughness is often due to rail corrugation which can be removed by grinding. A method has been developed to assess periodically the rail roughness on each railway line of the network, to compare it with the average wheel roughness for that line and to determine whether a noise reduction can be achieved by grinding the rail. Roughness measurements can be carried out with an instrumented coach. The two axle-boxes of a measurement wheelset are equipped with accelerometers. Together with the train speed and the right frequency filter, the accelerometer signal is used to produce a wavelength spectrum of the rail roughness. To determine the average wheel roughness on a given line, the so-called Acoustical Timetable can be used. This database comprises train types, train intensities and train speeds for each track section in the Netherlands. An average wheel roughness spectrum is known for each type of braking system. The number of trains of each type passing by on a certain track section determine the average roughness. Analysis of the data shows on which track sections the rail roughness exceeds the wheel roughness by a specified level difference. If this track section lies in a residential area, the decision can be made to grind this piece of track to reduce the noise production locally. Using this methodology, the noise production can be kept to a minimum, determined by the local average wheel roughness.

  17. Quantifying texture evolution during hot rolling of AZ31 Twin Roll Cast strip

    Science.gov (United States)

    Gorelova, S.; Schaeben, H.

    2015-04-01

    Multi-pass rolling experiments with an AZ31 Twin Roll Cast (TRC) alloy were performed on an industrial scaled four-high rolling mill. Within the rolling with an intermediate annealing the evolution of texture was investigated. To quantify the extent of preferred crystallographic orientation experimental X-ray pole figures were measured after different process steps and analyzed using the free and open Matlab® toolbox MTEX for texture analysis. The development of the fiber texture was observed and analyzed in dependence on rolling conditions. In the initial state the specimen exhibits a texture composed of a weak basal texture and a cast texture with {0001}-planes oriented across the rolling direction. During the following rolling process a fiber texture was developed. The expected strength increment of the fiber texture was quantitatively confirmed in terms of volume portions of the orientation density function around the fiber and in terms of the canonical parameters of fitted pseudo Bingham distributions. On the results of this work a model for prediction of the texture evolution during the strip rolling of magnesium in the examined parameter range was developed.

  18. NORMAL PRESSURE AND FRICTION STRESS MEASUREMENT IN ROLLING PROCESSES

    DEFF Research Database (Denmark)

    Henningsen, Poul; Arentoft, Mogens

    2005-01-01

    A load transducer has been developed to measure the contact forces in the deformation zone during rolling. The transducer consists of a strain gauge equipped insert, embedded in the surface of the roll. The length of the insert exceeds the contact length between material and roll. By analyzing the output from the transducer, the friction stress and normal pressure in the contact zone can be determined. The new concept differs from existing pin designs by a lower disturbance of lubricant film and material flow and limited penetration of material between transducer and roll. Aluminum, cupper and steel strips with a width of 40 mm was rolled with reduction varying from 2.7% to 29%, in a pilot mill. For evaluating the transducer, the measured contact forces are compared with external measurements of roll separating forces and torque. The determined friction coefficients are compared with values found by forward slip measurements.

  19. Rolling Process Modeling Report: Finite-Element Model Validation and Parametric Study on Various Rolling Process Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Soulami, Ayoub; Lavender, Curt A.; Paxton, Dean M.; Burkes, Douglas

    2015-06-15

    Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum alloy plate-type fuel for high-performance research reactors in the United States. This work supports the U.S. Department of Energy National Nuclear Security Administration’s Office of Material Management and Minimization Reactor Conversion Program. This report documents modeling results of PNNL’s efforts to perform finite-element simulations to predict roll-separating forces for various rolling mill geometries for PNNL, Babcock & Wilcox Co., Y-12 National Security Complex, Los Alamos National Laboratory, and Idaho National Laboratory. The model developed and presented in a previous report has been subjected to further validation study using new sets of experimental data generated from a rolling mill at PNNL. Simulation results of both hot rolling and cold rolling of uranium-10% molybdenum coupons have been compared with experimental results. The model was used to predict roll-separating forces at different temperatures and reductions for five rolling mills within the National Nuclear Security Administration Fuel Fabrication Capability project. This report also presents initial results of a finite-element model microstructure-based approach to study the surface roughness at the interface between zirconium and uranium-10% molybdenum.

  20. Conformational polymorphism on imatinib mesylate: grinding effects.

    Science.gov (United States)

    Grillo, Damián; Polla, Griselda; Vega, Daniel

    2012-02-01

    Crystal structures of polymorphs ? and ? of imatinib mesylate were obtained. Thermal behavior and grinding effects were studied by X-ray powder diffraction and differential scanning calorimetry techniques. Molecules in forms ? and ? exhibit significant conformational differences due to dissimilar intramolecular interactions, which stabilize their molecular conformations. In spite of that, both crystal structures present a dimer-chain arrangement. Dimers are mainly determined by hydrogen bonding interactions and some weak ?-? interactions. Connections between dimers are provided by mesylate ions to determine chains of dimers. Neighboring chains are linked by very weak interactions: C-H···? interactions in form ? and ?-? interactions in form ?. At room temperature, thermal disorder was observed in the mesylate ion in form ?, which could be removed at low temperatures (-123°C). Form ? was found to be the more stable form at room temperature. Both polymorphs exhibit a tendency to generate amorphous material by grinding, which can be converted to a crystalline phase by either temperature or aging. When amorphous crystallization is kinetically studied at room temperature, form ? is obtained after a week. Conversely, when the crystallization is activated by temperature, the final obtained crystal form depends on the starting material, proving the importance of seeding. PMID:21975944

  1. Stirred milling - new comminution technology in the PGM industry

    Scientific Electronic Library Online (English)

    C.M., Rule.

    Full Text Available Stirred milling using either horizontal or vertical mills has made a rapid entrance into PGM ore and tailings concentrator flow sheets. Currently there are in excess of 40 units installed in either mainstream, 'MIG' or intermediate concentrate regrind, 'UFG', applications in PGM, primary ore treatme [...] nt plants or in tailings scavenging and reclamation treatment plants. This represents a total of approximately 70 MW of installed fine grinding equipment. This paper outlines the reasons why the technology take-up has been rapid and illustrates the advantages of this technology over conventional milling.

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

    DEFF Research Database (Denmark)

    Lagergren, Jonas; Wanheim, Tarras

    2005-01-01

    Background/purpose The only way to establish the true rolling pressure and the true friction condition in cold rolling is to conduct measurements in the roll bite. A new transducer design is therefore proposed, this to overcome problems in previous measurements in the past 70 years. Method The new idea is to increase the contact surface of the transducer, to be larger than the arc of contact. This is in the opposite way, compared to the smaller and smaller contact pin design that has been prevailing. Results The measurements where conducted during cold dry rolling of both copper strips and stainless steel strips in a pilot mill. The recordings were selected from a steady state with no disturbance from the material flow. The transducer was able to simultaneously measure both the normal pressure and the friction stress. An estimation of the coefficient of friction was accordingly performed. Conclusions The new transducer works very well, it was seen to be robust and able to avoid signal disturbance. The pressure and friction stress distribution results was as expected by the authors and a good reproducibility, together with a proven agreement between recorded signals and signals simulated. Keywords Friction stress, normal pressure distribution, roll bite measurements, cold flat rolling of metals

  3. Three-dimensional measurement and characterization of grinding tool topography

    Science.gov (United States)

    Cui, Changcai; Blunt, Liam; Jiang, Xiangqian; Xu, Xipeng; Huang, Hui; Ye, Ruifang

    2013-01-01

    A comprehensive 3-dimensional measurement and characterization method for grinding tool topography was developed. A stylus instrument (SOMICRONIC, France) was used to measure the surface of a metal-bonded diamond grinding tool. The sampled data was input the software SurfStand developed by Centre for Precision Technology (CPT) for reconstruction and further characterization of the surface. Roughness parameters pertaining to the general surface and specific feature parameters relating to the grinding grits, such as height and angle peak curvature have been calculated. The methodology of measurement has been compared with that using an optical microscope. The comparison shows that the three-dimensional characterization has distinct advantages for grinding tool topography assessment. It is precise, convenient and comprehensive so it is suitable for precision measurement and analysis where an understanding of the grinding tool and its cutting ability are required.

  4. Development of a rolling technology for twin-roll cast magnesium strips

    Directory of Open Access Journals (Sweden)

    M. Ullmann

    2015-10-01

    Full Text Available With the best lightweight potential of all metallic construction materials, magnesium primarily helps to increase energy efficiency over the lifecycle of automotive and non-automotive industrial products. Yet to assess overall energy efficiency, the production process must also be taken into account. This paper provides an insight into the energy-efficient production of magnesium strips up to 0,8 mm in thickness based on twin-roll casting and strip rolling on an industrial scale, as developed at the Institute of Metal Forming at the Technical University Bergakademie Freiberg (Germany in cooperation with MgF Magnesium Flachprodukte GmbH (Germ any. The technology of twin-roll casting and strip rolling on a four-high reversing mill is described.

  5. GEOMETRICAL CHARACTERIZATION OF MICRO END MILLING TOOLS

    DEFF Research Database (Denmark)

    Borsetto, Francesca; Bariani, Paolo

    2004-01-01

    The milling process is one of the most common metal removal operation used in industry. This machining process is well known since the beginning of last century and has experienced, along the years, many improvements of the basic technology, as concerns tools, machine tools, coolants/lubricants, milling strategies and controls. Moreover the accuracy of tool geometry directly affects the performance of the milling process influencing the dimensional tolerances of the machined part, the surface topography, the chip formation, the cutting forces and the tool-life. The dimensions of certain geometrical details, as for instance the cutting edge radius, are determined by characteristics of the manufacturing process, tool material, coating etc. While for conventional size end mills the basic tool manufacturing process is well established, the reduction of the size of the tools required for the manufacturing of miniature parts by micro milling puts further challenges on to the manufacturing process. The whole geometry of the tools cannot be directly downscaled with the tool diameter. Besides the physical limit in the reduction of the cutting edge radius constituted by the grain size of sintered carbides the error motion during the grinding wheels do not allow using identical paths for tools having differences in diameter of more than one order of magnitude. Thus grinding paths for micro and mills are simplified in comparison to those for larger tools of similar shape. [1] The aim of the present report is to develop procedures for the geometrical characterization of micro end milling tools in order to define a method suitable for the quality assurance in the micro cutting field.

  6. Investigations of spherical grinding parameters on circularity error, finished diameter, and grinding forces for porous polyurethane foam

    Directory of Open Access Journals (Sweden)

    Isarawit Chaopanich

    2010-07-01

    Full Text Available The aim of this study was to examine the effect of grinding variables on the circularity error, finished diameter, andgrinding forces of porous polyurethane foam (PPUF. A cube of PPUF having the size of 21 mm was transformed into a roundshape using a vertical wheel grinding with the circular groove pad developed. The grinding speed (Vs of the wheel wasvaried between 1.41 and 5.18 m/s. The cross head speed of the circular groove pad (f was controlled at 1, 3, 5 mm/min. Theabrasive grit size (A of 20 and 53 ?m made of silicon carbide were applied. Two replications of experiment were randomlyperformed. Diameter and circularity error of the ground specimen were determined by vision measuring machine. The tangentialand normal forces of grinding were obtained using a dynamometer. The experimental data were statistically analyzed. The study found that (1 the grinding speed could remarkably affect the circularity error, finished diameter, and grinding forces,(2 the grinding speed ranged between 2.83 and 3.77 m/s could contribute to sphere shape specimens, and (3 the grinding speed of 3.30 m/s, cross head speed of 1 mm/min, and abrasive grit size of 20 ?m provided the least circularity error.

  7. Multi-stage FE simulation of hot ring rolling

    Science.gov (United States)

    Wang, C.; Geijselaers, H. J. M.; van den Boogaard, A. H.

    2013-05-01

    As a unique and important member of the metal forming family, ring rolling provides a cost effective process route to manufacture seamless rings. Applications of ring rolling cover a wide range of products in aerospace, automotive and civil engineering industries [1]. Above the recrystallization temperature of the material, hot ring rolling begins with the upsetting of the billet cut from raw stock. Next a punch pierces the hot upset billet to form a hole through the billet. This billet, referred to as preform, is then rolled by the ring rolling mill. For an accurate simulation of hot ring rolling, it is crucial to include the deformations, stresses and strains from the upsetting and piercing process as initial conditions for the rolling stage. In this work, multi-stage FE simulations of hot ring rolling process were performed by mapping the local deformation state of the workpiece from one step to the next one. The simulations of upsetting and piercing stages were carried out by 2D axisymmetric models using adaptive remeshing and element erosion. The workpiece for the ring rolling stage was subsequently obtained after performing a 2D to 3D mapping. The commercial FE package LS-DYNA was used for the study and user defined subroutines were implemented to complete the control algorithm. The simulation results were analyzed and also compared with those from the single-stage FE model of hot ring rolling.

  8. Off-line calculation of pass schedule for hot rolling stainless steel strip and establishment of model parameters for on-line set up calculation

    International Nuclear Information System (INIS)

    In this paper, the method to calculate the roughing and finishing rolling forces is described. The way to establish the model parameters for on-line process set up calculation during developing hot rolling stainless steel strip in 2050mm hot rolling mill of Baosteel, is also introduced. Rolling test shows that the rolling forces calculated by on-line process set up model agree well with measured data. (author)

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

    International Nuclear Information System (INIS)

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

  10. Tandem strip mill's multi-parameter coupling dynamic modeling based on the thickness control

    Science.gov (United States)

    Peng, Yan; Zhang, Yang; Sun, Jianliang; Zang, Yong

    2015-03-01

    The rolling process is determined by the interaction of a number of different movements, during which the relative movement occurs between the vibrating roll system and the rolled piece, and the roll system's vibration interacts with the strip's deformation and rigid movement. So many parameters being involved leads to a complex mechanism of this coupling effect. Through testing and analyzing the vibration signals of the mill in the rolling process, the rolling mill's coupled model is established with comprehensive consideration of the coupling interaction between the mill's vertical vibration, its torsional vibration and the working roll's horizontal vibration, and vibration characteristics of different forms of rolling mill's vibration are analyzed under the coupling effect. With comprehensive attention to the relationship between the roll system, the moving strip and the rolling parameters' dynamic properties, and also from the strip thickness control point of view, further research is done on the coupling mechanism between the roll system's movement and the moving strip's characteristics in the rolling process. As a result, the law of inertial coupling and the stiffness coupling effect caused by different forms of the roll system's vibration is determined and the existence of nonlinear characteristics caused by the elastic deformation of moving strip is also found. Furthermore, a multi-parameter coupling-dynamic model is established which takes the tandem strip mill as its research object by making a detailed kinematics analysis of the roll system and using the principle of virtual work. The coupling-dynamic model proposes the instruction to describe the roll system's movement, and analyzes its dynamic response and working stability, and provides a theoretical basis for the realization of the strip thickness' dynamic control.

  11. Calucaltion of waste heat from hot rolled steel coils at SSAB and its recovery

    OpenAIRE

    Yousaf, Naeem

    2009-01-01

    Hot rolling process is heat input process. The heat energy in hot rolled steel coils can be utilized. At SSAB Strip Product Borlänge when the hot rolled steel coils came out of the hot rolling mill they are at the temperature range of 500°C to 800°C. Heat energy contained by the one hot rolled steel coil is about 1981Kwh whereas the total heat energy for the year 2008 is 230 GWh/year.The potential of heat is too much but the heat dissipation rate is too slow. Different factors on which heat ...

  12. Development of a modified grind-leach process for processing Triso-coated reactor fuel

    International Nuclear Information System (INIS)

    An advanced or modified grind-leach process has been under development as a head-end treatment to separate the fuel components from spent tri-structural-isotropic (TRISO)-coated fuel and to prepare the fuel for separations in a standard aqueous processing plant. Conceptually, the process involves removing the fuel compacts from the graphite fuel element, grinding the compacts to expose the fuel kernel, optionally separating the lighter carbon particles from the heaver fuel particles and leaching or dissolving the fuel components from the remaining carbon and silicon carbide fines. The nitric acid leaching step may be directly interfaced with conventional aqueous solvent extraction processes. The finely divided carbon waste may be reformed into a compact and durable waste form. Laboratory studies of the key process steps have been performed using surrogates because irradiated fuels were not available. The fuel compacts may be removed from the graphite block to eliminate nearly all the block-graphite and thus the primary source of organic by-products in the leaching step. Tests have been recently completed to study the milling process. Using commercially available laboratory-scale jet mills, tests with surrogate fuel particles, including TRISO-coated zirconia and hafnia, showed that the friable coatings could be stripped from the relatively tough kernels. The coating fragments were very small, whereas the kernel fragments were larger. Similar results were obtained with arger. Similar results were obtained with unirradiated coated urania kernels. Because the coating layers were milled to very small particle sizes, it was anticipated that acids would have good access to the fuel components. This mitigates losses of fuel materials embedded in the coatings. With the coatings breached or removed, the kernels would tend to dissolve completely. These tests strongly indicate that jet milling produces a product conducive to acid leaching. Proof-of-principle tests using simulated crushed TRISO-coated fuel have indicated little, if any, production of soluble organic species in the leaching process. Nitric acid leaching of milled surrogate TRISO-coated fuel followed by filtering produced a clear yellow solution. This solution was used in shake-out tests with uranium extraction solvent (tri-n-butyl phosphate in n-dodecane diluent). No physical process problems such as foaming, formation of emulsions, or failure to achieve clean phase separation were observed. Negligible effects on the solvent extraction process were evidenced by measured distribution ratios close to expected values. These initial studies indicate that the modified crush-leach process is suitable for processing of TRISO-coated fuels. Further studies using irradiated fuels are recommended. Processes to fabricate a carbon waste form should also be tested. (authors)

  13. Model Predictive Control for an Industrial SAG Mill

    DEFF Research Database (Denmark)

    Ohan, Valeriu; Steinke, Florian

    2012-01-01

    We discuss Model Predictive Control (MPC) based on ARX models and a simple lower order disturbance model. The advantage of this MPC formulation is that it has few tuning parameters and is based on an ARX prediction model that can readily be identied using standard technologies from system identication. When applied to MIMO systems we call this controller a MIMO-ARX based MPC. We use an industrial Semi-Autogenous Grinding (SAG) mill to illustrate the performance of this controller. SAG mills are the primary units in a grinding chain and also the most power consuming units. Therefore, improved control of SAG mills has the potential to signicantly improve eciency and reduce the specic energy consumption for mineral processes. Grinding circuits involving SAG mills are multivariate processes. Commissioning of a control system based on a classical single-loop controllers with logic is time consuming, while MPC has the potential to both improve the control performance and the commissioning time and expertise required. The simulation results demonstrate that the MPC based on a MIMO-ARX model is able to provide nice control performance measured by its ability to track an output reference and reject unknown disturbances. Furthermore, the method used to design the controller represents a systematic method that can be automatized for wide-spread deployment in industrial environments.

  14. High-speed milling of light metals

    Directory of Open Access Journals (Sweden)

    F. Cus

    2007-09-01

    Full Text Available Purpose: of this paper: Introduction applicability of high-speed cutting of light metals is presented in this paper.Design/methodology/approach: HSC is the result of numerous technical advances ensuring that milling has become faster than conventional milling and has gained importance as a cutting process. The advantages of the HSC milling are higher productivity owing to the reduction of machining times increase of the flow time of production, reduction of the number of technological operations, increase of the surface quality and longer service life of tools. The machining conditions for execution of the HSC (36000min-1 and feeding 20m/min require modernly built machine tools to meet those machining conditions.Findings: Continuous development of new materials is more and more dynamical, particularly, in the automobile, aircraft and electronic industry and in the manufacture of various mechanical parts. Also the achievements in the area of building of machines and tools, ensuring high cutting speeds (highly efficient machining have contributed to development of the process.Research limitations/implications: High quality of the surfaces, the quality of this so-called HSC milling can be compared to grinding.Practical implications: High-speed milling of light metals from aluminium and magnesium is more and more frequently used in practice. This result is high quality of the surface and shorter machining times. In some cases when machining by grinding is specified, the latter is omitted.Originality/value: The applicability of high-speed milling has proved to be successful, when aluminum and magnesium alloying materials are machined.

  15. Rescheduling a three shift system at a steel rolling mill: effects of a one hour delay of shift starting times on sleep and alertness in younger and older workers.

    OpenAIRE

    Rosa, R. R.; Ha?rma?, M.; Pulli, K.; Mulder, M.; Na?sman, O.

    1996-01-01

    OBJECTIVE: To evaluate a new work schedule at a Finnish steel mill with special attention to effects on older workers. The schedule was designed to improve sleep before the morning shift, and alertness during the morning shift, by delaying shift start and end times. METHODS: Evaluation was by a shiftwork health and safety questionnaire, recordings of work-rest-sleep cycles with activity monitors worn on the wrist, daily diaries, and on site computerised testing of fatigue and alertness by the...

  16. Production of scallop shell nanoparticles by mechanical grinding as a formaldehyde adsorbent

    International Nuclear Information System (INIS)

    Scallop shells, which are a waste product in the seafood industry, are disposed more than 200,000 ton per year in Hokkaido, Japan. We report effective uses and simple application for discarded shells as a formaldehyde adsorbent. The adsorption performance of scallop shells to remove formaldehyde vapor is investigated. Planetary ball milling under dry conditions and subsequent water addition realize shells with a crystallite size (35–90 nm) and equivalent size of the specific surface area (41–191 nm) in the nanometer range. The comminution properties of the scallop shells, especially the grinding limit, are estimated via a semi-theoretical consideration for the grinding limit. Additionally, the adsorbed amount of gaseous formaldehyde using a self-designed adsorption line is estimated. The nanosized scallop shells exhibit an excellent adsorption performance rather than the feed shell, and the adsorbed amount is positively correlated with the specific surface area of the shell. Hence, scallop shells have potential to adsorb volatile organic compounds.

  17. Innovative grinding wheel design for cost-effective machining of advanced ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Licht, R.H.; Kuo, P.; Liu, S.; Murphy, D.; Picone, J.W.; Ramanath, S.

    2000-05-01

    This Final Report covers the Phase II Innovative Grinding Wheel (IGW) program in which Norton Company successfully developed a novel grinding wheel for cost-effective cylindrical grinding of advanced ceramics. In 1995, Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics using small prototype wheels. The Phase II program was initiated to scale-up the new superabrasive wheel specification to larger diameters, 305-mm to 406-mm, required for most production grinding of cylindrical ceramic parts, and to perform in-house and independent validation grinding tests.

  18. Minimizing the edge buckling of the cold roll-forming process

    International Nuclear Information System (INIS)

    In this work, the cold roll-forming process was numerically simulated by MSC SuperForm 2002 software based on finite element method. The strips were modelled with U-profile and a pre-punched hole located at the web zone was introduced. Two different configurations of the roll-forming mills were simulated, named as the Conventional and Curved. The conventional roll-forming mill was obtained by using the same diameters of the bottom rolls. The downhill roll-forming mill was achieved by increasing the diameters of the bottom rolls. This study investigated the occurrence of edge buckling in the hole lateral edge of the pre-punched sheet during the forming process. It could be concluded that, during the cold roll-forming process, reducing or even eliminating the compression stress in the web zone by the downhill roll-forming mill is possible to minimize occurrence of the edge buckling in the hole lateral edge of the pre-punched sheet during the forming process.

  19. Pole-placement optimizing controller and application to a simulated autogeneous grinding circuit

    International Nuclear Information System (INIS)

    An optimizing controller is developed in order to operate the process at its optimum according to an unconstrained criterion despite disturbances. The gradient of the criterion is taken as the controlled variable and a null set point is used in order to maximize the criterion. A local dynamic moving average model is identified and its gain is calculated to evaluate the gradient on-line. A low-forgetting factor in conjunction with a fixed low-pass filter is used in order to fix the dynamic response of the measured gradient. A multivariable controller using a pole cancellation method is used to achieve zero gradient set point. The method is applied to the optimization of the power drawn by a simulated autogeneous grinding mill. (author)

  20. Effect of grinding on thermal reactivity of ceramic clay minerals.

    Czech Academy of Sciences Publication Activity Database

    Balek, Vladimír; Perez-Magueda, L. A.; Poyato, J.; ?erný, Zbyn?k

    2007-01-01

    Ro?. 88, ?. 1 (2007), s. 87-91. ISSN 1388-6150 Institutional research plan: CEZ:AV0Z40320502 Keywords : DTA * emanation thermal analysis * grinding Subject RIV: CA - Inorganic Chemistry Impact factor: 1.483, year: 2007

  1. Surface topography of parallel grinding process for nonaxisymmetric aspheric lens

    International Nuclear Information System (INIS)

    Workpiece surface profile, texture and roughness can be predicted by modeling the topography of wheel surface and modeling kinematics of grinding process, which compose an important part of precision grinding process theory. Parallel grinding technology is an important method for nonaxisymmetric aspheric lens machining, but there is few report on relevant simulation. In this paper, a simulation method based on parallel grinding for precision machining of aspheric lens is proposed. The method combines modeling the random surface of wheel and modeling the single grain track based on arc wheel contact points. Then, a mathematical algorithm for surface topography is proposed and applied in conditions of different machining parameters. The consistence between the results of simulation and test proves that the algorithm is correct and efficient. (authors)

  2. A critical study of high efficiency deep grinding

    CERN Document Server

    Johnstone, I

    2002-01-01

    The recent years, the aerospace industry in particular has embraced and actively pursued the development of stronger high performance materials, namely nickel based superalloys and hardwearing steels. This has resulted in a need for a more efficient method of machining, and this need was answered with the advent of High Efficiency Deep Grinding (HEDG). This relatively new process using Cubic Boron Nitride (CBN) electroplated grinding wheels has been investigated through experimental and theoretical means applied to two widely used materials, M50 bearing steel and IN718 nickel based superalloy. It has been shown that this grinding method using a stiff grinding centre such as the Edgetek 5-axis machine is a viable process. Using a number of experimental designs, produced results which were analysed using a variety of methods including visual assessment, sub-surface microscopy and surface analysis using a Scanning Electron Microscope (SEM), residual stress measurement using X-Ray Diffraction (XRD) techniques, Ba...

  3. Uranium milling

    International Nuclear Information System (INIS)

    The historical development of the U milling industry is described. Flowsheets showing the material flow in U mills are included. The general drop in ore grade with time and the need for preconcentration are pointed out. Recent developments include thickeners, continuous ion exchange, U recovery from copper leaching operations and gold ore, resin in pulp recovery, etc

  4. Critical review of Nanofluid Minimum Quantity Lubrication for Grinding application

    OpenAIRE

    Mr. Prashant J. Patil,; Dr. CHANDRAKANT R. PATIL

    2014-01-01

    In recent years, the environment has become one of the most important subject. Emulsion-based cooling fluids are used in grinding for a variety of reasons such as improving surface finish, wheel life, flushing away chips, reducing workpiece thermal deformation. Due to large fluid delivery an extensive amount of mist is generated during grinding process. The workers who breathe in this hazardous mist is having health hazard. There are two alternative for large cutting fluids. O...

  5. Performance analysis of magnesium phosphate cement mortar containing grinding dust

    OpenAIRE

    Daniel Véras Ribeiro; Márcio Raymundo Morelli

    2009-01-01

    Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP), which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0 to 30% weight) of grinding dust were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the mortars in t...

  6. Development of morphology in laser dressed grinding wheels

    OpenAIRE

    Jackson, M. J.; G.M. Robinson

    2007-01-01

    Purpose: The paper describes the development of faceted morphology in laser dressed grinding wheels.Design/methodology/approach: The approach used in the paper is based on locally melting a vitrified grinding wheel and measuring features such as grain size, cooling rate and melt depth as a function of laser fluence and relating these measures to the morphology shown in the microstructures presented in the paper.Findings: The findings of this course of research lead the authors to believe that...

  7. Applying laser irradiation and intelligent concepts to identify grinding phenomena

    OpenAIRE

    Mohammed, Arif

    2012-01-01

    The research discussed in this thesis explores a new method for the detection of grinding burn temperature using a laser irradiation acoustic emission (AE) sensing technique. This method is applicable for the grinding process monitoring system, providing an early warning for burn detection on metal alloy based materials (specifically nickel alloy based materials: Inconel718 and MarM002). The novelty in this research is the laser irradiation induced thermal AE signal that represents the grindi...

  8. Prediction of residual stresses due to grinding with phase transformation

    OpenAIRE

    Shah, Syed Mushtaq Ahmed

    2011-01-01

    Grinding is a commonly used finishing process to produce components of desired shape, size and dimensional accuracy. The ultimate goal is to have the maximum workpiece quality, minimum machining time and high economic efficiency by making a selective adaptation of the possible process strategy and chosen parameter selection. The focus of this study arose from a limitation that challenges the grinding industry. The production rate of the ground parts is generally constrained by surface topogra...

  9. Teeth Grinding: Is Emotional Stability related to Bruxism?

    OpenAIRE

    Sutin, Angelina R.; Terracciano, Antonio; Ferrucci, Luigi; Costa, Paul T.

    2010-01-01

    This study examines the association between personality traits and bruxism, the repetitive grinding or clenching of teeth. Community-dwelling participants (N = 470) had a comprehensive oral examination by a dentist and completed a dental history and personality questionnaires. Consistent with the literature on state anxiety and depression as antecedents of bruxism, Neuroticism-related traits were associated with self-reported teeth grinding. These traits were also associated with other oral c...

  10. Environmental Impact of Electricity Consumption in Crushing and Grinding Processes of Traditional and Urban Gold Mining by Using Life Cycle Assessment (LCA

    Directory of Open Access Journals (Sweden)

    Nur Rafidah Yahaya

    2012-01-01

    Full Text Available Mining is not only an essential component of social and economic development since prehistoric time, but it also gives a large impact on our civilization. Gold is a noble metal that is highly valued. The extraction of minerals from earth is known as traditional mining. Gold also can be extracted from electronic waste or e-waste, and this new concept is called urban mining. There are many stages in traditional and urban mining process. However, in this study, the focus was on crushing and grinding processes to produce 1 kg of gold. Crushing and grinding are processes in the milling stage. This research evaluates and compares the environmental impacts of crushing and grinding processes, based on electricity consumption. About 50 to 65% of total electricity in milling was used for crushing and grinding processes. Life Cycle Assessment (LCA methodology was used as a tool to evaluate the environmental burdens of electricity usage in converting ore and electronic waste to gold bars. The Life Cycle Impact Assessment (LCIA of this process was interpreted by using Eco-indicator 99 assessment methods in SimaPro software. The impact categories included in this study were carcinogens, respiratory organics, respiratory inorganics, radiation, climate change, ozone layer, ecotoxicity, acidification or eutrophication, land use and minerals. The results showed that crushing and grinding from traditional mining gave the largest impact to the environment with single score of 399 Pt compared to the urban mining with only 1.81 Pt score. The highest impact in both types of mining is to human health.

  11. Amorphization of NiZr2 under ball-milling: validation of the milling intensity

    International Nuclear Information System (INIS)

    Studies of amorphization of NiZr2 compound have been carried out in a magneto ball-mill capable to operate in two milling mode, depending of the direction of the applied magnetic field. The first mode favours ball impacts and the second one cold rolling. We show that much in the same way as in a vertical frame grinder, the compound reaches a two phase (amorphous plus crystalline) steady structure and that the volume fraction of amorphous phase depends at given milling temperature on the milling intensity. The milling intensity is as defined by Chen, the momentum transferred per unit mass of powder per unit time : the higher the milling intensity, the higher the fraction of amorphous phase. However the intensity required to reach a given fraction of amorphous phase in the magneto ball-mill seems to be much lower than in the vertical frame grinder. The rolling mode is found to be more efficient than the impact mode at equivalent milling temperature for promoting amorphization. (orig.)

  12. Grinding process monitoring based on electromechanical impedance measurements

    Science.gov (United States)

    Marchi, Marcelo; Guimarães Baptista, Fabricio; de Aguiar, Paulo Roberto; Bianchi, Eduardo Carlos

    2015-04-01

    Grinding is considered one of the last processes in precision parts manufacturing, which makes it indispensable to have a reliable monitoring system to evaluate workpiece surface integrity. This paper proposes the use of the electromechanical impedance (EMI) method to monitor the surface grinding operation in real time, particularly the surface integrity of the ground workpiece. The EMI method stands out for its simplicity and for using low-cost components such as PZT (lead zirconate titanate) piezoelectric transducers. In order to assess the feasibility of applying the EMI method to the grinding process, experimental tests were performed on a surface grinder using a CBN grinding wheel and a SAE 1020 steel workpiece, with PZT transducers mounted on the workpiece and its holder. During the grinding process, the electrical impedance of the transducers was measured and damage indices conventionally used in the EMI method were calculated and compared with workpiece wear, indicating the surface condition of the workpiece. The experimental results indicate that the EMI method can be an efficient and cost-effective alternative for monitoring precision workpieces during the surface grinding process.

  13. Understanding and improving electroluminescence in mill-ground ZnS : Cu,Cl phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Medling, S; France, C; Balaban, B; Kozina, M; Jiang, Y; Bridges, F; Carter, S A, E-mail: smedling@ucsc.edu [Physics Department, University of California, Santa Cruz, CA 95064 (United States)

    2011-05-25

    We demonstrate that lightly milled ZnS : Cu,Cl phosphors produce AC electroluminescence (EL) emission in devices half as thick and produce up to 5 times the light output as the thinnest devices made with unground phosphors. We also establish minimum and maximum bounds on micro-milling conditions for producing powders that are still viable for AC EL. To understand the cause of the minimum size, we report extended x-ray absorption fine structure (EXAFS) measurements on phosphors sorted by particle size. The EXAFS data show that grinding preferentially damages the initially embedded CuS nano-precipitate. This suggests that grinding cleaves the ZnS : Cu through the embedded CuS nano-precipitates, leaving the CuS nano-precipitates on the surface to be further broken apart by continued grinding, eventually reducing the effectiveness of the CuS-induced electric field enhancement.

  14. Modeling and Optimization of Face Milling Operation Based on Response Surface Methodology and Genetic Algorithm

    OpenAIRE

    Kannan S; Baskar. N

    2013-01-01

    Materials are manufactured from casting, forging and extrusion processes have higher typical dimension tolerences due to its producing ability. So machining processes were introduced for close tolerence asssembly and improve the product working efficiencies. In response, now a day’s lot of machining processes are available such as turning, milling, drilling and grinding to overcome these problems. Milling operation is playing vital role on making the components with high accuracy and higher ...

  15. Numerical simulation in roll pass design for bar rolling

    Directory of Open Access Journals (Sweden)

    S. A. Aksenov

    2015-01-01

    Full Text Available The application of finite element simulation to the problem of roll pass design for round bar rolling is considered. Two roll pass sequences were developed by analytical methods and then optimized using 2.5D Finite Element Method (FEM. The first one is a classical oval-round roll pass design. The second one is a combination of flat rolls and round roll passes. Relying on the simulation data obtained by FEM, the roll gaps were adjusted to achieve the required bar shape and the uniform distribution of rolling force between the passes. Advantages and disadvantages of each roll pass design were considered.

  16. Influence of clinker grinding-aids on the intrinsic characteristics of cements and on the behaviour of mortars

    Directory of Open Access Journals (Sweden)

    Fernández Luco, L.

    2003-12-01

    Full Text Available In the production of portland cement, grinding aids are used to improve the grinding stage and reduce the energy required to achieve the required fineness. These additives remain in the final product and they might influence the characteristics and properties of the cement, and thus, mortar and concrete. This paper presents an evaluation of two grinding-aid additives used in the production of portland cement ground in a ball mill at a laboratory stage, with suitable proportions of portland cement clinker and gypsum. A control cement mix was also produced without using any admixture and the results are shown on a comparative basis. Conclusions indicate that grinding-aids additives have some influence on the characteristics of portland cement produced, increasing their specific surface and modifying microstructure and its packing ability. Mortars and concretes made with cements ground with the addition of gringing-aids exhibit higher strength at any age and a reduced water demand. Special attention should be taken to consider any interaction with water-reducing admixture in concretes and mortars.

    En la fabricación de cemento portland es una práctica creciente la utilización de aditivos para optimizar el proceso de molienda; éstos quedan incorporados en el producto final y pueden influir sobre las características y propiedades del cemento, morteros y hormigones. En este trabajo se presenta la evaluación de dos aditivos comerciales en la molienda conjunta de clínker de cemento portland y yeso comercial, tratados en un molino a bolas a escala de laboratorio, en forma comparativa con un cemento sin aditivo producido en forma equivalente. Las conclusiones indican que los aditivos de molienda tienen influencia en las características del cemento resultante, incrementando su superficie y modificando su microestructura y estado de agregación; los morteros mejoran sus prestaciones mecánicas a todas las edades y se reduce la demanda de agua, aunque debe prestarse cuidado a las posibles interacciones con aditivos reductores de agua de hormigones.

  17. Aplicação de prensas de rolos em minério de ferro High pressure grinding rolls for iron ore

    OpenAIRE

    Farley Santos Ribeiro; José Francisco Cabello Russo; Thiago Costa

    2010-01-01

    O Projeto Minas-Rio, de propriedade da Anglo Ferrous Brazil, prevê a utilização de prensa de rolos para cominuição do undersize do peneiramento (-25,4 mm). Esta é uma aplicação que se torna cada dia mais comum, porém relativamente nova em minério de ferro. Foram realizados estudos no Centro de Pesquisa da Krupp/Polysius na Alemanha, com o objetivo de validar a aplicação de prensa de rolos para minério de ferro, de determinar os principais parâmetros usados no dimensionamento e de avaliar o im...

  18. Preparation and characterization of co-grinded mixtures of aceclofenac and neusilin US2 for dissolution enhancement of aceclofenac.

    Science.gov (United States)

    Vadher, Ambarish H; Parikh, Jolly R; Parikh, Rajesh H; Solanki, Ajay B

    2009-01-01

    The present study was carried out with a view to enhance the dissolution of poorly water-soluble BCS-class II drug aceclofenac by co-grinding with novel porous carrier Neusilin US(2.) (amorphous microporous granules of magnesium aluminosilicate, Fuji Chemical Industry, Toyama, Japan). Neusilin US(2) has been used as an important pharmaceutical excipient for solubility enhancement. Co-grinding of aceclofenac with Neusilin US(2) in a ratio of 1:5 was carried out by ball milling for 20 h. Samples of co-ground mixtures were withdrawn at the end of every 5 h. and characterized for X-ray powder diffraction, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The analysis revealed the conversion of crystalline aceclofenac to its amorphous form upon milling with Neusilin US(2). Further, in vitro dissolution rate of aceclofenac from co-ground mixture was significantly higher compared to pure aceclofenac. The accelerated stability study of co-ground mixture was carried out at 40 degrees C/75%RH for 4 weeks, and it showed that there was no reversion from amorphous to crystalline form. Thus, it is advantageous to use a porous carrier like Neusilin US(2) in improvement of dissolution of poorly soluble drugs. PMID:19444620

  19. Rolling Shutter Motion Deblurring

    KAUST Repository

    Su, Shuochen

    2015-06-07

    Although motion blur and rolling shutter deformations are closely coupled artifacts in images taken with CMOS image sensors, the two phenomena have so far mostly been treated separately, with deblurring algorithms being unable to handle rolling shutter wobble, and rolling shutter algo- rithms being incapable of dealing with motion blur. We propose an approach that delivers sharp and undis torted output given a single rolling shutter motion blurred image. The key to achieving this is a global modeling of the camera motion trajectory, which enables each scanline of the image to be deblurred with the corresponding motion segment. We show the results of the proposed framework through experiments on synthetic and real data.

  20. Development of morphology in laser dressed grinding wheels

    Directory of Open Access Journals (Sweden)

    M.J. Jackson

    2007-05-01

    Full Text Available Purpose: The paper describes the development of faceted morphology in laser dressed grinding wheels.Design/methodology/approach: The approach used in the paper is based on locally melting a vitrified grinding wheel and measuring features such as grain size, cooling rate and melt depth as a function of laser fluence and relating these measures to the morphology shown in the microstructures presented in the paper.Findings: The findings of this course of research lead the authors to believe that a specific morphology is dependent upon cooling rate and laser fluence.Research limitations/implications: The findings show that further research is required to fully understand how certain morphologies form as a function of cooling rate and laser fluence. It should be noted that morphologies observed in laser processed grinding wheels include cellular and fully dendritic morphologies in addition to faceted vertices.Practical implications: The results imply that laser dressed grinding wheels can be used for machining different materials at different grinding speeds. The paper also shows that much development is needed to identify laser processing conditions that are appropriate for different workpiece materials.Originality/value: The paper shows that different morphologies can be used to machine workpiece materials under different conditions. The originality in the paper is focused on the formation on minute cutting points using increasing laser fluences.

  1. Fatigue Tests on Welded Joints Improved by Grinding

    DEFF Research Database (Denmark)

    Agerskov, Henning; BjØrnbak-Hansen, JØrgen

    2003-01-01

    The present project is a part of an investigation on the fatigue life of the welded structure of large two-stroke diesel engines. Of special interest has been a study of the improvement in fatigue life, due to grinding of the weld toes. The test series carried through showed a significant increase in fatigue life due to the grinding, ranging from a factor of approx. 2.8 to infinity, depending on the load level. With the limited number of tests carried out, S-N lines have not been determined. However, the results obtained indicate a change in slope of the S-N line from approx. 3.0 for the test series without grinding to approx. 6.4 for the test series with grinding. In one of the test series (No. 7), the crack initiation in most tests moved from the weld toe to the non-ground surface between the ground areas at the weld toes, due to the grinding.

  2. Effect of Carbon Content in Stainless Steels on Quantity of Grinding Energy

    Directory of Open Access Journals (Sweden)

    Wójcik R.

    2014-10-01

    Full Text Available The paper presents a study of the process of grinding stainless steels with different carbon contents. Verified the size and scope of the energy which is introduced in the surface layers for different types of abrasive grains and binders. The influence of parameters in plunge grinding process was considered in studies. The energy ratio was used for this purpose, which was calculated by multiplying energy and time of grinding wheel contact with the workpiece. To investigate influence of different carbon content on the level of energy density generated during grinding process special parameter Bp have been evaluated. The grinding tests were conducted in dry grinding technique.

  3. Determination of the relative position between grinding wheel and a cylindrical workpiece on a 7 axis grinding machine by acoustic emission

    Scientific Electronic Library Online (English)

    Walter Lindolfo, Weingaertner; Adriano, Boaron.

    2012-03-01

    Full Text Available The contact between grinding wheel and workpiece in the grinding process is recognized by acoustic emission (AE). Two acoustic emission monitoring systems (MS) were integrated into a 3 axis CNC grinding machine. A laptop allows the signal acquisition and visualization. The acquired AE RMS signals fr [...] om the contact between tool and workpiece are analyzed permitting to establish the most suitable AE monitoring system to recognize the contact in a particular grinding machine. In a second experimental setup the selected MS was installed on a 7 axis tool grinding machine at an industrial partner. At this partner, the relative position between grinding wheel and workpiece was previously determined manually. This procedure has a direct influence on the results depending on the technical skills of the operator. The automation of this activity supported by acoustic emission has led to satisfactory results regarding the relative position between grinding wheel and workpiece and contributed to the setup time reduction.

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

    Directory of Open Access Journals (Sweden)

    ROMAN, N.

    2010-02-01

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

  5. Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material

    Directory of Open Access Journals (Sweden)

    M. Drobne

    2014-10-01

    Full Text Available Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for roll’s shell material. To obtain corresponding parameters, a rectangular single edge notched bend specimens – SENB, according to standard BS 7448, were used. The fatigue crack growth analysis was done on a resonant testing machine with use of special crack gauges, while for fracture mechanics parameters the electro–mechanical testing machine was used.

  6. In-process grinding monitoring through acoustic emission

    Scientific Electronic Library Online (English)

    Paulo R., Aguiar; Paulo J. A., Serni; Fábio R. L., Dotto; Eduardo C., Bianchi.

    2006-03-01

    Full Text Available This work aims to investigate the efficiency of digital signal processing tools of acoustic emission signals in order to detect thermal damages in grinding processes. To accomplish such a goal, an experimental work was carried out for 15 runs in a surface grinding machine operating with an aluminum [...] oxide grinding wheel and ABNT 1045 Steel as work material. The acoustic emission signals were acquired from a fixed sensor placed on the workpiece holder. A high sampling rate data acquisition system working at 2.5 MHz was used to collect the raw acoustic emission instead of the root mean square value usually employed. Many statistical analyses have shown to be effective to detect burn, such as the root mean square (RMS), correlation of the AE, constant false alarm rate (CFAR), ratio of power (ROP) and mean-value deviance (MVD). However, the CFAR, ROP, Kurtosis and correlation of the AE have been presented more sensitive than the RMS.

  7. Potential release of carbon nanotubes from their composites during grinding

    Science.gov (United States)

    Ogura, I.; Kotake, M.; Shigeta, M.; Uejima, M.; Saito, K.; Hashimoto, N.; Kishimoto, A.

    2013-04-01

    We investigated the particle release caused by the grinding of polystyrene-based composites with and without single-wall carbon nanotubes (CNTs). In the results of real-time aerosol monitoring, considerable increases in the number concentration of nano-sized aerosol particles were observed during the grinding of both CNT-containing and CNT-free polystyrene. When a thermodenuder was used, the number of released nanoparticles was reduced by over 99.9%, indicating that the nanoparticles were presumably volatile particles released by the friction heat produced by grinding the composite. In an electron microscopic analysis of the aerosol particles, micron-sized particles with protruding fibers (probably CNTs) were observed, whereas free-standing CNTs were not observed.

  8. Performance analysis of magnesium phosphate cement mortar containing grinding dust

    Scientific Electronic Library Online (English)

    Daniel Véras, Ribeiro; Márcio Raymundo, Morelli.

    2009-03-01

    Full Text Available Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP), which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate ce [...] ment were molded and varying amounts (0 to 30% weight) of grinding dust were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the mortars in terms of microstructure (SEM), mechanical strength and capillary water absorption was verified. The results obtained proved very satisfactory for the use of this waste as an additive in magnesium phosphate mortars.

  9. Analysis of cement superplasticizers and grinding aids a literature survey

    International Nuclear Information System (INIS)

    This literature survey reviews the methods for analysis of cement plasticizers and organic grounding aids in cement solutions in preparation of grouts/concrete and methods for determination of plasticizers and grinding aids in groundwater conditions. The survey focuses on three different types of superplasticizers: sulphonated naphthalene condensates, sulphonated melamine condensates and polycarboxylates. There are various organic grinding aids, such as alkanolamines, glycols or phenolic compounds, used in the cement industry. This review is concerned with the following compounds: triethylenetetramine, tetraethylenepentamine, diethanolamine, triethanolamine, triisopropanolamine, ethyleneglycol, diethyleneglycol, aminoethylethanolamine, hydroxyethyl diethylenetriamine and phenol. (orig.)

  10. IMPROVING ENERGY EFFICIENCY VIA OPTIMIZED CHARGE MOTION AND SLURRY FLOW IN PLANT SCALE SAG MILLS

    Energy Technology Data Exchange (ETDEWEB)

    Raj K. Rajamani; Sanjeeva Latchireddi; Sravan K. Prathy; Trilokyanath Patra

    2005-12-01

    The U.S. mining industry operates approximately 80 semi-autogenesis grinding mills (SAG) throughout the United States. Depending on the mill size the SAG mills draws between 2 MW and 17 MW. The product from the SAG mill is further reduced in size using pebble crushers and ball mills. Hence, typical gold or copper ore requires between 2.0 and 7.5 kWh per ton of energy to reduce the particle size. Considering a typical mining operation processes 10,000 to 100,000 tons per day the energy expenditure in grinding is 50 percent of the cost of production of the metal. A research team from the University of Utah is working to make inroads into saving energy in these SAG mills. In 2003, Industries of the Future Program of the Department of Energy tasked the University of Utah team to build a partnership between the University and the mining industry for the specific purpose of reducing energy consumption in SAG mills. A partnership was formed with Cortez Gold Mines, Kennecott Utah Copper Corporation, Process Engineering Resources Inc. and others. In the current project, Cortez Gold Mines played a key role in facilitating the 26-ft SAG mill at Cortez as a test mill for this study. According to plant personnel, there were a number of unscheduled shut downs to repair broken liners and the mill throughput fluctuated depending on ore type. The University team had two softwares, Millsoft and FlowMod to tackle the problem. Millsoft is capable of simulating the motion of charge in the mill. FlowMod calculates the slurry flow through the grate and pulp lifters. Based on this data the two models were fine-tuned to fit the Cortez SAG will. In the summer of 2004 a new design of shell lifters were presented to Cortez and in September 2004 these lifters were installed in the SAG mill. By December 2004 Cortez Mines realized that the SAG mill is drawing approximately 236-kW less power than before while maintaining the same level of production. In the first month there was extreme cycling and operators had to learn more. Now the power consumption is 0.3-1.3 kWh/ton lower than before. The actual SAG mill power draw is 230-370 kW lower. Mill runs 1 rpm lesser in speed on the average. The re-circulation to the cone crusher is reduced by 1-10%, which means more efficient grinding of critical size material is taking place in the mill. All of the savings have resulted in reduction of operating cost be about $0.023-$0.048/ ton.

  11. Process parameter dependent growth phenomena of naproxen nanosuspension manufactured by wet media milling.

    Science.gov (United States)

    Bitterlich, A; Laabs, C; Krautstrunk, I; Dengler, M; Juhnke, M; Grandeury, A; Bunjes, H; Kwade, A

    2015-05-01

    The production of nanosuspensions has proved to be an effective method for overcoming bioavailability challenges of poorly water soluble drugs. Wet milling in stirred media mills and planetary ball mills has become an established top-down-method for producing such drug nanosuspensions. The quality of the resulting nanosuspension is determined by the stability against agglomeration on the one hand, and the process parameters of the mill on the other hand. In order to understand the occurring dependencies, a detailed screening study, not only on adequate stabilizers, but also on their optimum concentration was carried out for the active pharmaceutical ingredient (API) naproxen in a planetary ball mill. The type and concentration of the stabilizer had a pronounced influence on the minimum particle size obtained. With the best formulation the influence of the relevant process parameters on product quality was investigated to determine the grinding limit of naproxen. Besides the well known phenomenon of particle agglomeration, actual naproxen crystal growth and morphology alterations occurred during the process which has not been observed before. It was shown that, by adjusting the process parameters, those effects could be reduced or eliminated. Thus, besides real grinding and agglomeration a process parameter dependent ripening of the naproxen particles was identified to be a concurrent effect during the naproxen fine grinding process. PMID:25766272

  12. Roll force prediction of high strength steel using foil rolling theory in cold skin pass rolling

    Energy Technology Data Exchange (ETDEWEB)

    Song, Gil Ho; Jung, Jae Chook [Rolling and Measurement Research Group of Posco Technical Research Laboratory, Pohang (Korea, Republic of)

    2013-02-15

    Skin pass rolling is a very important process for applying a certain elongation to a strip in the cold rolling and annealing processes, which play an important role in preventing the stretching of the yield point when the material is processed. The exact prediction of the rolling force is essential for obtaining a given elongation with the steel grade and strip size. Unlike hot rolling and cold rolling, skin pass rolling is used to apply an elongation of within 2% to the strip. Under a small reduction, it is difficult to predict the rolling force because the elastic deformation behavior of the rolls is complicated and a model for predicting the rolling force has not yet been established. Nevertheless, the exact prediction of the rolling force in skin pass rolling has gained increasing importance in recent times with the rapid development of high strength steels for use in automobiles. In this study, the possibility of predicting the rolling force in skin pass rolling for producing various steel grades was examined using foil rolling theory, which is known to have similar elastic deformation behavior of rolls in the roll bite. It was found that a noncircular arc model is more accurate than a circular model in predicting the roll force of high strength steel below TS 980 MPa in skin pass rolling.

  13. CISM Course on Rolling Contact Phenomena

    CERN Document Server

    Kalker, Joost

    2000-01-01

    Preface.- Rolling Contact Phenomena - Linear Elasticity.- Finite Element Methods for Rolling Contact.- Plastic Deformation in Rolling Contact.- Non-Steady State Rolling Contact and Corrugations.- Modelling of Tyre Force and Moment Generation.- Rolling Noise.- Lubrication

  14. Study on the influence of shear and impact forces on the phase transformations of materials for mechanical treatment in a planetary ball mill

    International Nuclear Information System (INIS)

    The influence of milling on the transformations of the calcium carbonate phase has been studied using a laboratory centrifuge mill as well as a high energy planetary mill for grinding. The second one was fitted with two motors for freely selecting the translation and rotation movements of the grinding jars and therefore to vary the relative contribution of the shear and impact forces. The transformation phase of the calcite and aragonite has been observed although it is not thermodynamically aided. This transformation is helped by the application of shear forces more than by the energy released by the impact of the balls against the grinding material. A mechanism is proposed that explains this behavior (CW)

  15. The Ball Mill Driving Device Fault and the Main Bearing Lubrication Analysis

    Directory of Open Access Journals (Sweden)

    Tong Junfeng

    2013-04-01

    Full Text Available This article from the analysis of the power consumption of the ball mill and the work characteristic of the motor, analyzes the fault reason of ball mill transmission equipment. The paper mainly deals with a side-transmission ball mill. The main fault is about the breakdown in the elastic rubber coupling of the transmission system. It is found from the analysis of the real cases and data that the actual power consumption is increased and it is caused by the overload. The main parameters which influence the ball mill power consumption are load of the mill, feed material mass, ball mill rotational speed and friction. The main part of power consumption for ball mill is used to elevating grinding body and material, a portion is used to overcome the friction force between the main bearing. Under the conditions in which the load of the mill and feed material mass are kept the same, the parameters which influence the ball mill power consumption are rotational speed and friction status. When the ball mill voltage decreased, according to the motor characteristics, its rotation speed will decrease, which will disrupt the hydrodynamic lubrication state of the hollow shaft and spherical surface, so that the power consumption of the ball mill increase. The larger power leads to the transmission fault. This paper also put forward to make sure kept the ball mill main bearing lubrication status.

  16. Numerical simulation in roll pass design for bar rolling

    OpenAIRE

    S. A. Aksenov; E. N. Chumachenko; I. V. Logashina; T. Kubina

    2015-01-01

    The application of finite element simulation to the problem of roll pass design for round bar rolling is considered. Two roll pass sequences were developed by analytical methods and then optimized using 2.5D Finite Element Method (FEM). The first one is a classical oval-round roll pass design. The second one is a combination of flat rolls and round roll passes. Relying on the simulation data obtained by FEM, the roll gaps were adjusted to achieve the required bar shape and the uniform distrib...

  17. Effect of Roll Material on Surface Quality of Rolled Aluminum

    Science.gov (United States)

    Zhao, Qi

    The surface defects of aluminum alloys that have undergone hot rolling were studied. The effects of different roll materials, of the number of rolling passes and of lubrication on surface defects of hot rolled aluminum alloys were investigated by laboratory hot rolling. Two different aluminum alloys, Al-Mn and Al-Mg, were each rolled against three different steel alloy rolls, AISI 52100, AISI 440C and AISI D2. The results showed that different roll materials do affect the morphology of the mating aluminum alloy surface with apparent surface defects, which included magnesium and oxygen rich dark regions on both alloys. The carbide protrusions in 440C and D2 steel rolls are confirmed to be responsible for the dark, rich magnesium and oxygen regions on both the rolled Al-Mn and Al-Mg alloy surfaces. As the number of passes increases, Mg and O deposit in the form of patches and grain boundaries near the surface area.

  18. 7.SP Rolling Dice

    Science.gov (United States)

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Roll two dice 10 times. After each roll, note whether any sixes were observed and record your results in the table below. RollAny Sixes?(Y/N) 1 2 3 4 5...

  19. The Graduate Grind: A Critical Look at Graduate Education

    Directory of Open Access Journals (Sweden)

    Annabelle L. Grundy

    2003-07-01

    Full Text Available Abandonment, abuse, anxiety, betrayal, bitterness, breaking point, burnout, collapse, danger, death, desperation, discouragement, divorce, exhaustion, frustration, grind, hardships, hazing, hurdles, ignorance, impossible dream, isolation, killing the spirit, leaving, loneliness, murder, neglect, peril, ridicule, ritual, self-protection, sexual harassment, shock, snobbery, strain, strangulation, stress, suffering, suicide, survival of the fittest, trauma, and violence.

  20. The Graduate Grind: A Critical Look at Graduate Education

    OpenAIRE

    Annabelle L. Grundy; McGinn, Michelle K.

    2010-01-01

    Abandonment, abuse, anxiety, betrayal, bitterness, breaking point, burnout, collapse, danger, death, desperation, discouragement, divorce, exhaustion, frustration, grind, hardships, hazing, hurdles, ignorance, impossible dream, isolation, killing the spirit, leaving, loneliness, murder, neglect, peril, ridicule, ritual, self-protection, sexual harassment, shock, snobbery, strain, strangulation, stress, suffering, suicide, survival of the fittest, trauma, and violence.

  1. Global analysis of aerodynamics deflectors efficiency in the grinding process

    Scientific Electronic Library Online (English)

    Rodrigo E., Catai; Eduardo C., Bianchi; Felipe M., Zilio; Ivan de D., Valarelli; Manoel C. de S., Alves; Leonardo R., Silva; Paulo R. de, Aguiar.

    2006-06-01

    Full Text Available The conventional grinding methods in some cases are not very efficient because the arising of thermal damages in the pieces is very common. Optimization methods of cutting fluid application in the grinding zone are essential to prevent thermal problems from interaction of the wheel grains with the w [...] orkpiece surface. The optimization can happen through the correct selection of the cut parameters and development of devices that eliminate air layer effects generated around the grinding wheel. This article will collaborate with the development of an experimentation methodology which allows evaluating, comparatively, the performance of the deflectors in the cutting region to minimize the air layer effect of the high speed of the grinding wheel. The air layers make the cutting fluid jet to dissipate in the machine. An optimized nozzle was used in order to compare the results with the conventional method (without baffles or deflectors) of cutting fluid application. The results showed the high eficciency of the deflectors or baffles in the finish results.

  2. Grinding performance of pellet prepared using nanosize ceria particles

    International Nuclear Information System (INIS)

    The cerium oxide particles of single crystal were obtained only by the combination of precipitation method and hydrothermal treatment at lower temperature than 200 deg. C. The particles showed plate-like shape even in the particle size of about 4 nm, and the plate-like plane was identified to be (1 1 1) from the observation of lattice images. By heating at 100-700 deg. C in air, the particle size was increased from about 4 to 60 nm maintaining the plate-like shape with elevating the temperature. These cerium oxide particles were applied as a fine abrasive grain for mirror grinding. We manufactured a grinding pellet, consisting of the plate-like cerium oxide particles, using electrophoretic deposition (EPD) phenomenon. It is called 'ceria EPD pellet'. As a result of grinding of quartz-crystal wafer using the ceria EPD pellet, fine mirror surface with roughness less than 1 nmRy was realized. Grinding efficiency of the ceria EPD pellet was fourth time as high as a silica EPD pellet

  3. Chemical pretreatment of coal in a stirred ball mill: Fossil Energy quarterly report, April 1, 1987-June 30, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Birlingmair, D.; Burkhart, L.; Firth, G.; Pollard, J.; Clements, J.

    1987-08-01

    Coal was chemically pretreated in a stirred ball mill to demonstrate the effects of pre-conditioning of coal surfaces during comminution to ultrafine sizes prior to separation. The physical cleaning technique chosen for this test was microbubble flotation. The introduction of a collector before or after grinding in alkaline, neutral, or acidic media was compared. Observations made with different grinding times showed that froths with smaller bubbles are more effective in separating finer particle sizes. Limestone was also used as an additive in the stirred ball mill to act both as a grinding aid and as a sulfur scavenger during combustion. The results of simulating combustion under conditions similar to those found in fluidized bed combustors indicated that 50 to 60% of the sulfur in the coal can be reacted and removed with the ash. 5 refs., 4 figs., 9 tabs.

  4. Hydrogenation of nanostructured graphite by mechanical grinding under hydrogen atmosphere

    International Nuclear Information System (INIS)

    Orimo et al. reported that nanostructured graphite, prepared by using the mechanical grinding under hydrogen atmosphere, contained more than 7 mass% of hydrogen whose thermal desorption spectrum (TDS) showed characteristic two peaks; one is at around 700 K and the other around 1000 K [Appl. Phys. Lett. 75 (1999) 3093; Appl. Phys. A72 (2001) 167; J. Appl. Phys. 90 (2001) 1545]. We confirmed this claim; namely, c.a. 4.5 mass% of hydrogen was detected by TDS in the desorbed gas from graphite powder mechanically ground under hydrogen in a Cr/Ni steel mortar. Yet the mechanism of hydrogenation and the physico-chemical state of adsorbed hydrogen are not known well. We found that the amount of contained hydrogen depends significantly on the grinding mortar. When a Cr steel mortar was used, we obtained 2 mass%; and when an agate mortar was used, only a trace amount of hydrogen was detected. The transmission electron microscopy and the X-ray powder diffractometry indicated that the nanostructured graphite ground in steel mortars contained a large quantity of cementite, Fe3C, to which the iron element was supplied by wearing out of mortar walls during the grinding. We examined the influence of metal particles by intentionally adding iron and nickel powder into graphite during the grinding in the metal-free agate mortar. Although in the agate mortar with metallic additives the hydrogenation did not proceed as much as in the steel mortar, the TDS spectrum showed characeel mortar, the TDS spectrum showed characteristic features. The presence of catalytic metal particles seems to be a prerequisite for the hydrogenation of graphite under hydrogen by mechanical grinding

  5. Grooved roll for a high speed twin roll caster

    Directory of Open Access Journals (Sweden)

    T. Haga

    2008-04-01

    Full Text Available Purpose: Purpose of this paper is investigation of the effect of roll-surface on the strip-surface. Improvement ofsmall cracks on the strip-surface was tried and effect of groove at the roll surface on the strip surface was shown.Design/methodology/approach: Method used in the present study was high speed twin roll caster withgrooved roll. Two kinds of grooves were used: one was parallel groove and the other was cross groove machinedby knurling and bite attached to a lathe.Findings: Findings of this research are that grooved roll was effective to eliminate the small cracks on the stripsurface. The contact condition between the roll and the melt became uniform by the small groove on the rollsurface. Contact area became small, and heat transfer between the melt and roll became small, too. As the result,chill structure did not become columnar, and crack did not occur. Groove pattern on the strip surface could beerased by the cold rolling.Research limitations/implications: Research limitation is that groove life could not be investigated.Practical implications: Practical implications are as below. The roll load was small and strip was not hot-rolledin a high speed twin roll caster. The grooved roll made strip-surface sound. Grooved 600mm width roll was tested,and usefulness of the grooved roll was shown.Originality/value: In the present study effect of the grooved roll on a high speed twin roll caster was investigated.

  6. Characterization of coal-water slurries produced in a high-speed stirred-ball mill

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, R.K.

    1987-01-01

    A comparison of energy requirements and rheological properties has been carried out for grinding of coal/water slurries produced in high-speed stirred and conventional ball mills. In each case, a linear population balance model using specific energy input as a reduced time variable resulted in a satisfactory description of the size distributions. The effect of stirrer speeds and fractional media filling on the energy efficiency has been studied. The pin device stirred mill was found to out perform the disc device stirred mill for this application. An approach of response surface methodology has been used to evaluate the optimal conditions of grinding. The operating variables examined were percent solids, ball size, dispersant dosage and mill speed. The results of grinding experiments based on central composite design have been evaluated in terms of slurry rheology and desired distribution modulus. Comparison of conventional and stirred milling tests showed that the energy reduction which is possible with the stirred ball mill increases linearly with the percent of material passing 325 mesh up to 90% and beyond this point energy reduction is even higher. Coal/Water slurries were found to behave as pseudoplastic fluids and data fitted to a power law type of relationship. Slurries produced to a fineness of 80% passing 250 mesh in conventional and stirred mills showed that the slurry prepared in a stirred mill was more viscous at low shear rates (<30(1/sec)) and less viscous at high shear rates. The rheological results and explained in terms of characteristic shape of the size distributions and shape of particles produced in each device. A comparison of pumping power requirements to transport these slurries produced in each device has been carried out based on rheological data.

  7. High coercivity induced by mechanical milling in cobalt ferrite powders

    International Nuclear Information System (INIS)

    In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe2O4 treated by mechanical milling with different grinding balls. The cobalt ferrite nanoparticles were prepared using a simple hydrothermal method and annealed at 500 °C. The non-milled sample presented coercivity of about 1.9 kOe, saturation magnetization of 69.5 emu/g, and a remanence ratio of 0.42. After milling, two samples attained coercivity of 4.2 and 4.1 kOe, and saturation magnetization of 67.0 and 71.4 emu/g respectively. The remanence ratio MR/MS for these samples increase to 0.49 and 0.51, respectively. To investigate the influence of the microstructure on the magnetic behavior of these samples, we used X-ray powder diffraction (XPD), transmission electron microscopy, and vibrating sample magnetometry. The XPD analysis by the Williamson–Hall plot was used to estimate the average crystallite size and strain induced by mechanical milling in the samples. - Highlights: • Magnetic behavior of milled CoFe2O4 is studied. • The coercivity is increase of about 150%. • The remanence ratio are increase to all milled samples. • The strain and pinning effects are observed in milled samples

  8. High coercivity induced by mechanical milling in cobalt ferrite powders

    Energy Technology Data Exchange (ETDEWEB)

    Ponce, A.S. [Instituto de Física, Universidade Federal de Mato Grosso, 78060-900, Cuiabá, MT (Brazil); Chagas, E.F., E-mail: efchagas@fisica.ufmt.br [Instituto de Física, Universidade Federal de Mato Grosso, 78060-900, Cuiabá, MT (Brazil); Prado, R.J. [Instituto de Física, Universidade Federal de Mato Grosso, 78060-900, Cuiabá, MT (Brazil); Fernandes, C.H.M.; Terezo, A.J. [Departamento de Química, Universidade Federal do Mato Grosso, 78060-900, Cuiabá, MT (Brazil); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150 Urca. Rio de Janeiro (Brazil)

    2013-10-15

    In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe{sub 2}O{sub 4} treated by mechanical milling with different grinding balls. The cobalt ferrite nanoparticles were prepared using a simple hydrothermal method and annealed at 500 °C. The non-milled sample presented coercivity of about 1.9 kOe, saturation magnetization of 69.5 emu/g, and a remanence ratio of 0.42. After milling, two samples attained coercivity of 4.2 and 4.1 kOe, and saturation magnetization of 67.0 and 71.4 emu/g respectively. The remanence ratio M{sub R}/M{sub S} for these samples increase to 0.49 and 0.51, respectively. To investigate the influence of the microstructure on the magnetic behavior of these samples, we used X-ray powder diffraction (XPD), transmission electron microscopy, and vibrating sample magnetometry. The XPD analysis by the Williamson–Hall plot was used to estimate the average crystallite size and strain induced by mechanical milling in the samples. - Highlights: • Magnetic behavior of milled CoFe{sub 2}O{sub 4} is studied. • The coercivity is increase of about 150%. • The remanence ratio are increase to all milled samples. • The strain and pinning effects are observed in milled samples.

  9. Experimental investigation of abrasive electrodischarge grinding of Ti6Al4V titanium alloy

    Directory of Open Access Journals (Sweden)

    R. ?wi?cik

    2009-12-01

    Full Text Available Purpose: This work is focused on determination of effects of grinding conditions on effectiveness of abrasive electrodischarge grinding (AEDG process applied for removal of machining allowance and forming of surface geometrical texture (SGT. These results were compared with one obtained for conventional grinding.Design/methodology/approach: The experimental investigations of deep-seated surface grinding of Ti6Al4V titanium alloy using CBN grinding wheel with metal bond were the ground for this elaboration. The effectiveness of AEDG process was assessed based on specific tangential grinding force and energy of spark electric discharge and machining results were estimated on geometrical structure parameters.Findings: The effectiveness of machining allowance removal depended on conditions of AEDG process. Significant differences in SGT formed by AEDG process and conventional grinding were revealed.Practical implications: Abrasive electrodischarge grinding is useful to be particularly suitable for efficient and effective grinding of very hard structural materials such as high-alloy steel, sintered carbides, metal-based composite materials etc.Originality/value: AEDG experiments were carried out using the typical surface finishing grinder and especially adapted generator of spark discharge pulses. The majority of such experiments in the world were performed with the electrodischarge machine tool equipped with extra grinding wheel mounted on the grinding pin and functioning as one of the electrodes put into operation via pneumatic drive.

  10. Performing in-feed type centerless grinding process on a surface grinder

    International Nuclear Information System (INIS)

    In our previous study, a new centerless grinding method using surface grinder was proposed. In this method, centerless grinding operations are performed by installing a compact centerless grinding unit, consisting mainly of an ultrasonic elliptic-vibration shoe, a blade and their respective holders, on the worktable of a surface grinder. During grinding, the cylindrical workpiece is held on the ultrasonic shoe and the blade, and its rotational motion is controlled by the elliptic motion of the shoe end-face. An actual unit had been produced and its performance in tangential-feed type centerless grinding using a surface grinder had been confirmed in the previous workd. In this paper, the performance of the grinding unit in in-feed centerless grinding operation was confirmed, and the effects of the main process parameter, i.e., eccentric angle, on the workpiece roundness was investigated experimentally. The obtained results showed that: (1) the centerless grinding unit performed well in in-feed type centerless grinding; (2) the eccentric angle affects roundness significantly, and its optimal angle is 6 deg.; (3) the workpiece roundness can be further improved by varying the eccentric angle during grinding, and the final roundness reached 0.65 ?m after grinding as the eccentric angle varied from 9 deg. to 6 deg. and to 3 deg.

  11. Uranium milling

    International Nuclear Information System (INIS)

    After a brief description of the broad categories and specific examples of uranium deposits around the world, the authors discuss the processes currently used in uranium ore milling. These include the preconcentration and comminution of ores, ore leaching at atmospheric and elevated pressures, the use of oxidants in leaching, alkaline leaching, solid-liquid separation using thickeners or filters, solution clarification, uranium recovery and purification processes, precipitation, product drying and packaging, and tailings disposal

  12. Effects of wet ball milling on lead stabilization and particle size variation in municipal solid waste incinerator fly ash.

    Science.gov (United States)

    Li, Ming-Guo; Sun, Chang-Jung; Gau, Sue-Huai; Chuang, Chia-Jung

    2010-02-15

    Water-extracted municipal solid waste incinerator (MSWI) fly ash was treated by a process of wet ball milling, using desalinated water as the milling solution. We investigated the influence of the milling process on the partitioning and leaching characteristics of lead (Pb) and the particle size distribution. The results show that 93.11% of the Pb was partitioned into the milled ash, 2.60% to the milling balls, and 0.17% to the inner surface of the milling jar, while amounts lower than the detection limit remained in the milled solution. As tested by the toxicity characteristic leaching procedure (TCLP), the leaching of Pb was inhibited after short-term grinding (from 5.2 to 1.2mg/L after 1h of milling), and further reduced by about 96% after 96h of ball milling. The mobility of the heavy metal was analyzed after a sequential extraction procedure. The results also show that Pb tended to become more stable after milling. The size distribution of particles was analyzed by a laser particle diameter analyzer and their morphology during grinding was observed using scanning electron microscopy. The median size of the fly ash decreased significantly from 36 to 5 microm after 0.5h of milling, but then only slightly, from 5 to 2 microm, with further milling from 0.5 to 96 h, due to the concurrent actions of fragmentation and/or agglomeration. The reason for the stabilization of Pb by ball milling was probably that Pb was sealed in the milled fly ash during the fragmentation and agglomeration of particles. PMID:19828240

  13. Effects of wet ball milling on lead stabilization and particle size variation in municipal solid waste incinerator fly ash

    International Nuclear Information System (INIS)

    Water-extracted municipal solid waste incinerator (MSWI) fly ash was treated by a process of wet ball milling, using desalinated water as the milling solution. We investigated the influence of the milling process on the partitioning and leaching characteristics of lead (Pb) and the particle size distribution. The results show that 93.11% of the Pb was partitioned into the milled ash, 2.60% to the milling balls, and 0.17% to the inner surface of the milling jar, while amounts lower than the detection limit remained in the milled solution. As tested by the toxicity characteristic leaching procedure (TCLP), the leaching of Pb was inhibited after short-term grinding (from 5.2 to 1.2 mg/L after 1 h of milling), and further reduced by about 96% after 96 h of ball milling. The mobility of the heavy metal was analyzed after a sequential extraction procedure. The results also show that Pb tended to become more stable after milling. The size distribution of particles was analyzed by a laser particle diameter analyzer and their morphology during grinding was observed using scanning electron microscopy. The median size of the fly ash decreased significantly from 36 to 5 ?m after 0.5 h of milling, but then only slightly, from 5 to 2 ?m, with further milling from 0.5 to 96 h, due to the concurrent actions of fragmentation and/or agglomeration. The reason for the stabilization of Pb by ball milling was probably that Pb was sealed in the milled fly ash during the fragmentation and ed fly ash during the fragmentation and agglomeration of particles.

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

    DEFF Research Database (Denmark)

    Lagergren, J.; Wanheim, Tarras

    2006-01-01

    The only way to establish the true rolling pressure and the true friction condition in cold rolling is to conduct measurements in the roll bite. A new transducer design is therefore proposed, in order to overcome problems in previous measurements in the past 70 years. The new idea is to increase the contact surface of the transducer, to be larger than the arc of contact. This is in contrast to the smaller and smaller contact pin design that has been prevailing. The measurements were conducted during cold dry rolling of both copper strips and stainless steel strips in a pilot mill. The recordings were selected from a steady state with no disturbance from the material flow. The transducer was able to simultaneously measure both the normal pressure and the friction stress. An estimation of the coefficient of friction was accordingly performed. The new transducer works very well, it was seen to be robust and able to avoid signal disturbance. The pressure and friction stress distribution results was as expected bythe authors and showed good reproducibility, together with a proven agreement between recorded and simulated signals.

  15. Simulation-Assisted Evaluation of Grinding Circuit Flowsheet Design Alternatives: Aghdarreh Gold Ore Processing Plant / Ocena Alternatywnych Schematów Technologicznych Procesu Rozdrabniania W Zak?adach Przeróbki Rud Z?ota W Aghdarreh, Z Wykorzystaniem Metod Symulacji

    Science.gov (United States)

    Farzanegan, A.; Ghalaei, A. Ebtedaei

    2015-03-01

    The run of mine ore from Aghdarreh gold mine must be comminuted to achieve the desired degree of liberation of gold particles. Currently, comminution circuits include a single-stage crushing using a jaw crusher and a single-stage grinding using a Semi-Autogenous Grinding (SAG) mill in closed circuit with a hydrocyclone package. The gold extraction is done by leaching process using cyanidation method through a series of stirred tanks. In this research, an optimization study of Aghdarreh plant grinding circuit performance was done to lower the product particle size (P80) from 70 ?m to approximately 40 ?m by maintaining current throughput using modeling and simulation approach. After two sampling campaigns from grinding circuit, particle size distribution data were balanced using NorBal software. The first and second data sets obtained from the two sampling campaigns were used to calibrate necessary models and validate them prior to performing simulation trials using MODSIM software. Computer simulations were performed to assess performance of two proposed new circuit flowsheets. The first proposed flowsheet consists of existing SAG mill circuit and a new proposed ball mill in closed circuit with a new second hydrocyclone package. The second proposed flowsheet consists of existing SAG mill circuit followed by a new proposed ball mill in closed circuit with the existing hydrocyclone package. In all simulations, SAGT, CYCL and MILL models were selected to simulate SAG mill, Hydrocyclone packages and ball mill units. SAGT and MILL models both are based on population balance model of grinding process. CYCL model is based on Plitt's empirical model of classification process in hydrocyclone units. It was shown that P80 can be reduced to about 40 ?m and 42 ?m for the first and second proposed circuits, respectively. Based on capital and operational costs, it can be concluded that the second proposed circuit is a more suitable option for plant grinding flowsheet modification. Surowy urobek z kopalni rud z?ota Aghdarreh musi najpierw zosta? poddany rozdrobnieniu, aby zapewni? efektywniejsze uwalnianie cz?steczek z?ota. W chwili obecnej obiegi rozdrabniania obejmuj? kruszenie jednostopniowe z wykorzystaniem kruszarek szcz?kowych oraz kruszenie jednostopniowe z u?yciem kruszarek pó?automatycznych w obiegu zamkni?tym z hydrocyklonem. Odzysk z?ota odbywa si? przy zastosowaniu procesu ?ugowania, z zastosowaniem metody cyjankowej w szeregu mieszalników. W pracy tej przeprowadzono optymalizacj? procesu rozdrabniania rud w zak?adach przeróbczych Aghdarreh prowadzonego w celu zmniejszenia rozmiarów uzyskiwanych cz?steczek z?ota (Ps0) z 70 ?m do ok. 40 ?m poprzez zapewnienie ci?g?o?ci procesu, z wykorzystaniem metod modelowania i symulacji. Na podstawie dwóch zestawów próbek z ci?gu technologicznego rozdrabniania, rozk?ady wielko?ci cz?stek zosta?y statystycznie zrównowa?one z wykorzystaniem oprogramowania NorBal. Pierwszy i drugi zbiór danych otrzymanych na podstawie dwóch zestawów próbek wykorzystany zosta? do kalibracji i walidacji modeli, przed przyst?pieniem do w?a?ciwych bada? symulacyjnych z u?yciem oprogramowania MODSIM. Symulacje komputerowe przeprowadzono w celu oceny wydajno?ci dwóch proponowanych ci?gów technologicznych. Pierwszy ci?g obejmuje istniej?ce kruszarki pó?automatyczne i nowo proponowan? kruszark? kulow? pracuj?c? w obiegu zamkni?tym z hydrocyklonem. Drugi rozwa?any ci?g stanowi istniej?ca kruszarka pó?automatyczna, nast?pnie proponowana kruszarka kulowa pracuj?ca w obiegu zamkni?tym z istniej?cym hydrocyklonem. We wszystkich symulacjach bazowano na modelach SAGT, CYCL i MILL do symulacji pracy kruszarek pó?automatycznych, pakietu hydrocyklonu oraz pojedynczych kruszarek. Modele SAGT i MILL oparte s? na modelu zrównowa?onej populacji w procesie rozdrabniania. Model CYCL opiera si? na empirycznym modelu klasyfikacji Plitta zastosowanym do hydrocyklonów. Wykazano, ?e rozmiar cz?stek zmniejszony zosta

  16. Rolling element fatigue testing of gear materials

    Science.gov (United States)

    Nahm, A. H.

    1978-01-01

    Rolling element fatigue lives of nine alloys were evaluated in Rolling Contact (RC) rigs. Test conditions included a Hertzian stress at 4,826 MPa (700 ksi), a rolling speed of 6.23 m/sec (245 in/sec.). Tests were run with a Type I oil (MIL-L-7808G) at room temperature. B-10 lives (10% failure rate) of alloys were compared versus reference alloys, VIM-VAR AISI M-50 and VAR AISI 9310. Six case carburizing alloys (AISI 9310, CBS600, CBS1000M, EX00014, Vasco X-2 and EX00053) and three through-hardening alloys (AISI M-50, VascoMax 350 and Vasco Matrix 2 evaluated, showed RCF performance inferior or equivalent to that of AISI 9310 and AISI M-50. It was also found that the effects of vacuum melting processes, different tempering temperatures, freezing cycle during heat treating, shot peening, gold plating and chrome plating employed in the present investigation did not significantly affect RCF life.

  17. Microstructure evolution during spray rolling and heat treatment of 2124 Al

    International Nuclear Information System (INIS)

    Spray rolling is a strip-casting technology that combines elements of spray forming and twin-roll casting. It consists of atomizing molten metal with a high velocity inert gas, quenching the resultant droplets in flight, and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets and conduction heat transfer at the rolls rapidly remove the metal's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly-solidified strip. Spray rolling operates at a higher solidification rate than conventional twin-roll casting and is able to process a broader range of alloys at high production rates. A laboratory-scale strip caster was constructed and used to evaluate the interplay of processing parameters and strip quality for strips up to 200 mm wide and 1.6-6.4 mm thick. This paper examines microstructure evolution during spray rolling and explores how gas-to-metal mass flow ratio influences the microstructure and mechanical properties of spray-rolled 2124 Al. The influences of solution heat treatment and cold rolling on grain structure and constituent particle spheroidization are also examined

  18. Calculation and Analysis of Temperature Distribution in Hot Rolling Strip

    OpenAIRE

    Kaixiang Peng

    2013-01-01

    Modern steel grades require constant and reproducible production conditions both in the hot strip mill and in the cooling section to achieve constant material properties along the entire strip length and from strip to strip. Calculation of the temperature in final rolling process always utilizes factors such as the work piece's inner organizational structure, plastic deformation, and it's variations of properties and so on, also as well as the physical parameters such as gauge, shape, etc. In...

  19. Developments in Electrical Discharge Grinding process: A review

    Directory of Open Access Journals (Sweden)

    Dr. Govindan P*1,

    2014-04-01

    Full Text Available Electrical discharge grinding (EDG is a hybrid process involving energy of sparking as well as mechanical grinding. The machining of thin and fragile material is very difficult for manufacturing industries and rapid demand of requirement could not be achieved. Electrical discharge machining is more acceptable machine tool for machining hard and brittle electrically conductive materials but its productivity is very low. In past decade, researchers have focused on EDG for machining these materials because there is no mechanical forces exerted on work piece during machining and it gives better performances than EDM due to the rotating speed of wheel. Therefore, the objective of this paper is to review the array of research works carried out on EDG process. It also focuses on recent developments for practical applications.

  20. FRACTURE FEATURES OF METAL BINDING WHEN DIAMOND-SPARK GRINDING

    Directory of Open Access Journals (Sweden)

    Yury GUTSALENKO

    2012-05-01

    Full Text Available The hypothesis of the influence of binding energy of metal on the processes of destruction and mass transfer at high-speed machining is considered. Some nonconventional processes of cleaning of intergranularity spaces from waste products at diamond-spark grinding are explained, the approach to assessment of metal resistance in these processes is proposed and eo ipso modern conception of processes in chip formation zone under condition of electric discharge effect is supplemented

  1. Control of Grinding Temperature by High Speed Air Jets

    OpenAIRE

    TORRANCE, ARCHIBALD ANDREW; MURRAY, DARINA BRIDGET; BABIC, DARKO M.

    2004-01-01

    Grinding, like other abrasive processes, may generate high local temperatures along the arc of cut. These can cause various forms of surface damage in the most sensitive finishing phase of the manufacturing cycle. Traditional cooling methods based on large amounts of water-oil emulsions can be both ineffective and environmentally unacceptable. A new approach to this problem has been devised utilizing the high penetrative power of fast air jets combined with a water/soap mist to greatly improv...

  2. Precision Grinding for Rapid Manufacturing of Large Optics

    OpenAIRE

    Tonnellier, Xavier

    2009-01-01

    Large scale nuclear fusion and astronomy scientific programmes have increased the demand for large freeform mirrors and lenses. Thousands of one metre class, high quality aspherical optical components are required within the next five to ten years. Current manufacturing process chains production time need to be reduced from hundred hours to ten hours. As part of a new process chain for making large optics, an efficient low damage precision grinding process has been proposed....

  3. A Novel and More Efficient Way to Grind Punching Tools

    OpenAIRE

    Krajnik, Peter; Drazumeric, Radovan; Badger, Jeffrey; Nicolescu, Mihai; Kopac, Janez

    2011-01-01

    A simulation model of punch grinding has been developed which calculates the instantaneous material-removal rate, arc length of contact and temperature based on the kinematic relationships between wheel and workiece and determines the optimum machine parameters to reduce cycle time and achieve a constant-temperature no-burn situation. Two basic outputs of the simulation model include arc length of contact and specific material-removal rate. A thermal model is included in the simulation to cal...

  4. Flow Stress Evaluation in Hot Rolling of Steel

    Science.gov (United States)

    Aghasafari, P.; Salimi, M.; Daraei, A.

    2014-08-01

    In this paper, an inverse analysis technique is used to obtain the flow curve of materials in a hot rolling finishing mill. This technique is based on minimization of the differences between the experimental and computed values. The flow curves and the friction coefficients at roll/work-piece interface are derived from two different models. Model I is based on simple slab method of analysis. Model II is based on a modified slab method in which the effect of shear stress in calculating the rolling force and torque is taken into account. It is shown that the developed inverse analysis technique is reliable and can simultaneously determine a more accurate flow stress for the material as well as a better estimation for the interface friction factors.

  5. The Effect of Moisture Content on Determining Corn Hardness from Grinding Time and Grinding Energy, and Hardness Prediction Using Near-Infrared Spectroscopy

    Science.gov (United States)

    The Stenvert hardness test was used to determine the energy-to-grind (ETG) and time-to-grind (TTG) of 107 food-grade corn hybrids at different moisture content (MC) levels. ETG and TTG were significantly affected by moisture content. Across hybrids, ETG displayed the most consistent response to MC...

  6. Possibilities of Pelletizing and Briquetting of Dusts from Castings Grinding

    Directory of Open Access Journals (Sweden)

    A. Pribulová

    2010-04-01

    Full Text Available Foundry dust can be divided into three groups: metallic dust with Fe content over 70%, mixed dust with Fe or SiO2 content between 10 –70% and sand wastes with minimum content of SiO2 about 70%. Dust from castings grinding with high Fe content (87.9% is still landfillin Slovakia. The aim of experiments with dust from grinding has been to find the cheapest way of dust agglomeration with minimumamount of binder because of melting in the electric induction furnace. The dust was pelletized and briquetted and as binders bentonite, water glass and cement were used. Briquettes made from dust from grinding with addition of water glass got compression strength after three months on the air about 82 kPa. Briquettes with addition of water glass were melted together with cast iron in electric induction furnace. Yield of metal from briquettes was around 80% and slag quantity around 4% (without briquettes the slag quantity was 1.4%.

  7. Measurement of drill grinding parameters using laser sensor

    Science.gov (United States)

    Yanping, Peng; Kumehara, Hiroyuki; Wei, Zhang; Nomura, Takashi

    2005-12-01

    To measure the grinding parameters and geometry parameters accurately for a drill point is essential to its design and reconditioning. In recent years, a number of non-contact coordinate measuring apparatuses, using CCD camera or laser sensors, are developed. But, a lot work is to be done for further improvement. This paper reports another kind of laser coordinate meter. As an example of its application, the method for geometry inspection of the drill flank surface is detailed. Measured data from laser scanning on the flank surface around some points with several 2-dimensional curves are analyzed with mathematical procedure. If one of these curves turns to be a straight line, it must be the generatrix of the grinding cone. Thus, the grinding parameters are determined by a set of three generatrices. Then, the measurement method and data processing procedure are proposed. Its validity is assessed by measuring a sample with given parameters. The point geometry measured agrees well with the known values. In comparison with other methods in the published literature, it is simpler in computation and more accurate in results.

  8. Control system for the surface quality of hot-rolled metal

    International Nuclear Information System (INIS)

    Full text: The modern ideas about quality of products are based on the principle of absolute satisfaction of the requirements and recommendations of the buyer. The presence of surface defects of steel-smelting and rolling origin is characteristic for the production of hot-rolling mill. The automatic surface inspection system (ASIS) includes two digital line video cameras for the filming of the upper and lower surface of the flat bar, a block for illumination of the upper and lower surface of the flat bar and a computer equipment. A system which secures 100 % control of the upper and lower surface of the rolled metal, detects automatically and classifies the sheet defects in the real time mode, was mounted 2003 for the first time in the domestic practice at the hot rolling mill 2000 JSC «Novolipetsk Iron & Steel Corporation» (NISC). The whole assortment of the mill 2000 was divided into five groups according to the outward appearance of the surface. The work on identifying the defects of hot-rolled metal and on widening the data base of knowledge of ASIS was continued after the guarantee tests. More than ten thousand images of defects were added to the data base during the year. key words: hot-rolling sheet, surface quality control, data base of defects

  9. Fast-roll inflation

    CERN Document Server

    Motohashi, Hayato; Yokoyama, Jun'ichi

    2014-01-01

    A novel class of exact solutions of inflationary dynamics with a specific form of a scalar potential is given based on a "fast-roll" ansatz, where the even-order slow-roll parameters approach to a nonnegligible constants while the odd ones are asymptotically vanishing in the quasi-de Sitter regime. Due to the rapid evolution of the background dynamics, the would-be decaying mode of the linear curvature perturbation may behave as a growing mode depending on the value of the model parameter, while the other mode remains constant. For the parameters giving a slightly red-tilted primordial power spectrum, the unwanted anomalous growth of the curvature perturbation is inevitable, which is similar to the case of the so-called ultra-slow-roll inflation.

  10. Roll over test.

    Science.gov (United States)

    Kassar, N S; Aldridge, J; Quirk, B

    1980-04-01

    Eighty-eight primigravidas underwent a roll over test performed according to the method suggested by Gant. A single individual performed the tests, and the results were withheld from the physician taking care of the patient. After delivery, 14 cases were excluded for various reasons, and, of the remaining 74 patients, 27 had negative results. Of these, 19 (70.4%) results were true negative and 8 (29.6%) were false negative. Forty-seven patients had a positive roll over test, of whom 35 (74.5%) did not develop hypertension in pregnancy and 12 (25.5%) did. The authors' results did not confirm the reliable predictive ability of the roll over test as reported by Gant and other investigators. PMID:7366894

  11. Uranium milling costs

    International Nuclear Information System (INIS)

    Basic process flowsheets are reviewed for conventional milling of US ores. Capital costs are presented for various mill capacities for one of the basic processes. Operating costs are shown for various mill capacities for all of the basic process flowsheets. The number of mills using, or planning to use, a particular process is reviewed. A summary of the estimated average milling costs for all operating US mills is shown

  12. Improving the Wear Behavior of WC-CoCr-based HVOF Coating by Surface Grinding

    Science.gov (United States)

    Maiti, A. K.; Mukhopadhyay, N.; Raman, R.

    2009-11-01

    WC-CoCr-based high velocity oxy fuel (HVOF) coatings are being used for several components which are prone to severe erosion or abrasion. In this study, the HVOF coating was applied by liquid fuel-based equipment. These coated samples were subjected to surface grinding of various depths (100, 200, and 300 ?m). Hardness test after surface grinding showed that the coating hardness increased by 33% after grinding to a depth of 200 ?m (1472 Hv). The residual stress after different depths of grinding was measured using x-ray diffraction. It showed that the compressive residual stress of coating increased with grinding. Increase in hardness of the coating (after grinding) is believed to be due to the increase in compressive residual stress. The abrasive wear resistance increased after grinding to a depth of 100 ?m thickness and remained constant during successive grinding. In contrast, the erosive wear resistance increased the most when the grinding thickness was 200 ?m. It is concluded that the surface grinding of coatings helps in increasing abrasive and erosive wear resistance. The increase in microhardness of the coating is believed to be the reason for high wear resistance. SEM studies of worn out surface show carbide grain pull out due to removal of softer phase, i.e. cobalt and chromium, and is followed by tungsten carbide grain pull out.

  13. Rolling Through a Vacuum

    CERN Document Server

    van der Schaar, Jan Pieter

    2013-01-01

    We clarify under what conditions slow-roll inflation can continue almost undisturbed, while briefly evolving through a (semi-classically) metastable false vacuum. Furthermore, we look at potential signatures in the primordial power spectrum that could point towards the existence of traversed metastable false vacua. Interestingly, the theoretical constraints for the existence of traversable metastable vacua imply that Planck should be able to detect the resulting features in the primordial power spectrum. In other words, if Planck does not see features this immediately implies the non-existence of metastable false vacua rolled through during the inflationary epoch.

  14. Ship Roll Motion Control

    DEFF Research Database (Denmark)

    Perez, Tristan University of Newcastle

    2010-01-01

    The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of deciencies in control system designs, which have proven to be far from trivial due to fundamental performance limitations. This tutorial paper presents an account of the development of various ship roll motion control systems and the challenges associated with their design. The paper discusses how to assess performance, the applicability of dierent models, and control methods that have been applied in the past.

  15. Slitting criterion for various rolling speeds in MSR rolling process

    Directory of Open Access Journals (Sweden)

    A. Stefanik

    2008-03-01

    Full Text Available Purpose: The main idea of MSR technology is the capability of producing two, three, four and even five rods simultaneously from a single strip in a hot rolling process. Correctly separation of the joined strips is the one of the mainly problem in MSR process. Changing the rolling speed may causes easier of the strand division. In this paper results of the computer simulation of the double slitting rolling process were presented.Design/methodology/approach: For numerical modelling of the multi rolling process a computer program Forge 2005, based by the finished element method was used. As a slitting criterion normalised Cockroft – Latham criterion was used.Findings: For the analysis performed in this study, it was found that increasing of the rolling speed causes of increasing the normalized Cockroft – Latham criterion. For the small values of rolling velocity the strip separation was easier.Research limitations/implications: Multi Slit Rolling process is applied in ribbed rods rolling. Adjusting of the rolling speed in multi slit rolling process could improve of the slitting band to the separated strips.Originality/value: Incorrect construction or bad gap matching could cause lack of separation propelled slitting rolls. The separation of the band is effected by means of separating rollers, which shape must be properly designed to suit to the slitting pass. Changing of the rolling speed could improve of the separation to the single strips.

  16. Surface integrity on grinding of gamma titanium aluminide intermetallic compounds

    Science.gov (United States)

    Murtagian, Gregorio Roberto

    Gamma-TiAl is an ordered intermetallic compound characterized by high strength to density ratio, good oxidation resistance, and good creep properties at elevated temperatures. However, it is intrinsically brittle at room temperature. This thesis investigates the potential for the use of grinding to process TiAl into useful shapes. Grinding is far from completely understood, and many aspects of the individual mechanical interactions of the abrasive grit with the material and their effect on surface integrity are unknown. The development of new synthetic diamond superabrasives in which shape and size can be controlled raises the question of the influence of those variables on the surface integrity. The goal of this work is to better understand the fundamentals of the abrasive grit/material interaction in grinding operations. Experimental, analytical, and numerical work was done to characterize and predict the resultant deformation and surface integrity on ground lamellar gamma-TiAl. Grinding tests were carried out, by analyzing the effects of grit size and shape, workpiece speed, wheel depth of cut, and wear on the subsurface plastic deformation depth (PDD). A practical method to assess the PDD is introduced based on the measurement of the lateral material flow by 3D non-contact surface profilometry. This method combines the quantitative capabilities of the microhardness measurement with the sensitivity of Nomarski microscopy. The scope and limitations of this technique are analyzed. Mechanical properties were obtained by quasi-static and split Hopkinson bar compression tests. Residual stress plots were obtained by x-ray, and surface roughness and cracking were evaluated. The abrasive grit/material interaction was accounted by modeling the force per abrasive grit for different grinding conditions, and studying its correlation to the PDD. Numerical models of this interaction were used to analyze boundary conditions, and abrasive size effects on the PDD. An explicit 2D triple planar slip crystal plasticity model of single point scratching was used to analyze the effects of lamellae orientation, material anisotropy, and grain boundaries on the deformation.

  17. Investigation into the causes of cracking of 2024 aluminium alloy during rolling operation

    International Nuclear Information System (INIS)

    Aluminium alloy 2024 bars cracked during cold rolling to produce strips conforming to T-3 temper designation. The specimens had reduced to 10 mm X 10 mm size by hot rolling rectangular ingots of size 25 mm X 25 mm in 3 passes using the rolling mill. Microscopic studies of the cracked specimens revealed the presence of inclusions on the grain boundaries and in the fracture valleys. Energy dispersive X-ray analysis (EDAX) indicated that inclusions were rich in iron. Fractrogapy of fracture specimens were carried out using both optical scanning electron microscopy which indicated brittle fracture due to the presence of iron inclusions. (author)

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

    DEFF Research Database (Denmark)

    Laugier, Maxime; Boman, Romain

    2014-01-01

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

  19. Development of Roller Ends Forced-Contact Model and Cambering Technology for UCM Temper Mill (I——Development of Roller Ends Forced-Contact Model and the Computational Model of Flatness for UCM temper mill

    Directory of Open Access Journals (Sweden)

    Zhenhua Bai

    2011-07-01

    Full Text Available Roller ends forced-contact and overmuch roll consumption are the widespread problems in temper rolling process of thin strip for two-stand UCM temper mill. Fully thinking the equipment and technology characteristics of UCM temper mill, we took the newly-built 1220 UCM temper mill of Baosteel as the research object in this paper. A model of roller ends forced-contact and a calculation model of flatness for UCM temper mill are established after a great deal of site tracing and theoretical researches. On this basis, an optimal mathematical model of roll shape which is suited for UCM temper mill is developed. Working roll curve is the combination of cosine curve and high order curve. The cosine subentry is used to control edge wave, the high order curve subentry is used to control roller ends forced-contact. Furthermore, the chamfering curve of middle roller end is optimized. Those are the innovations. Through the above-mentioned technology, pressure distribution between rollers caused by the shift of middle roll becomes more homogeneous, pressure peak disappeared, working life of roll is improved effectively as well. Relevant technologies have been used to the practice of 1220 UCM temper mill of Baosteel and have achieved good use effects, which is of further extending application value [1].

  20. / Analysis of the performance of superabrasive and alumina grinding wheels with different bonds and machining conditions

    Scientific Electronic Library Online (English)

    Eduardo Carlos, Bianchi; Paulo Roberto de, Aguiar; Rodrigo Daun, Monici; Luiz, Daré Neto; Leonardo Roberto da, Silva.

    2003-06-01

    Full Text Available This paper presents a review of researches on CBN (cubic boron nitride) grinding wheels with the purpose of identifying the state of art in abrasive machining and serving as the basis for future researches and laboratory tests. The scientific studies investigated here report on interesting results i [...] nvolving grinding, published by Brazilian and foreign authors. The methods and the results are presented and discussed. In addition, a grinding setup is presented which provides more reliable experimental results about the surface integrity of fragile materials. This setup was obtained for grinding tests in several grinding conditions during the wheel service life, using alumina and vitrified and resin bond CBN grinding wheels. Results of cutting force, surface roughness and G ratio are also presented and discussed. They confirm the excellent machining capacity of the CBN wheel, with stable behavior in cutting force and roughness results during the tests. The G ratio values are in agreement with the results found by other researchers.

  1. Isoflavone profile in soymilk as affected by soybean variety, grinding, and heat-processing methods.

    Science.gov (United States)

    Zhang, Yan; Chang, Sam K C; Liu, Zhisheng

    2015-05-01

    Isoflavones impart health benefits and their overall content and profile in foods are greatly influenced at each step during processing. In this study, 2 soybean varieties (Prosoy and black soybean) were processed with 3 different grinding (ambient, cold, and hot grinding) and heating methods (traditional stove cooking, 1-phase UHT, and 2-phase UHT) for soymilk making. The results showed after cold, ambient, and hot grinding, the total isoflavones were 3917, 5013, and 5949 nmol/g for Prosoy; the total isoflavones were 4073, 3966, and 4284 nmol/g for black soybean. Grinding could significantly increase isoflavone extraction. The grinding process had a destructive effect on isoflavones and this effect varied with grinding temperature. Different heating methods had different effects on different isoflavone forms. Two soybean varieties showed distinct patterns with respect to the change of isoflavone profile during processing. PMID:25827234

  2. Cylindrical grinding of SiC particles reinforced aluminium metal matrix composites

    Directory of Open Access Journals (Sweden)

    C. Thiagarajan

    2011-01-01

    Full Text Available This paper deals with an experimental study on the grindability of Al/SiC metal matrix composites in cylindrical grinding. Machining of metal matrix composites (MMCs is an area to be focused and finishing processes such as grinding to obtain a good surface finish and damage-free surfaces are crucial for the application of these materials. Nevertheless, grinding of MMCs has received little attention so far, thereby a detailed study on that has been carried out. In the present work, experiments are carried out to study the effect of grinding parameters; wheel velocity, work piece velocity, feed and depth of cut and SiC volume fraction percentage on the responses; grinding force, surface roughness and grinding temperature. Surface integrity of the ground surfaces is assessed using a scanning electron microscope (SEM. There are no cracks and defects found on the cylindrical ground surfaces at high wheel and work piece velocities, low feed and depth of cut.

  3. Investigation of possibility for rolled sheet steel production with improved mechanical properties

    International Nuclear Information System (INIS)

    Full text: In this research the technology process of obtaining a low -carbon hot rolled steel plates of structural steel S355J2+N was investigated. The normalization during rolling is the advantage of the process mentioned above. Due to this operation thermal treatment was avoided, the intended properties were achieved and the production efficiency was increased with preserving the quality of the final products. A deformation-speed regime of rolling was researched in details. On the base of that research an improved deformation speed regime was offered which allows improving of the mechanical properties of the material. key words: low -carbon hot rolled steel, deformation-speed regime, rolling mill, mechanical properties of the material

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

    Scientific Electronic Library Online (English)

    Péricles Guedes, Alves; José Adilson de, Castro; Luciano Pessanha, Moreira; Elder Moreira, Hemerly.

    2012-12-01

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

  5. Rolling Into Radians

    Science.gov (United States)

    2010-12-16

    This algebra lesson from Illuminations has students collect data for rolling objects of differing sizes in order to further understand periodic phenomena. They will then create two sinusoidal graphs of the data. Activity sheets and student questions are included. This material is intended for grades 9-12 and should require 1 class period to complete.

  6. Microstructure and properties of hot roll bonding layer of dissimilar metals. 2. Bonding interface microstructure of Zr/stainless steel by hot roll bonding and its controlling

    International Nuclear Information System (INIS)

    The hot roll bonding of zirconium and stainless steel inserted with tantalium was investigated using the newly developed rolling mill. The effect of hot rolling temperatures of zirconium/stainless steel joints on bonding interface structure was evaluated. Intermetallic compound layer containing cracks was observed at the bonding interface between stainless steel and tantalium when the rolling temperature was above 1373K. The hardness of the bonding layer of zirconium and tantalium bonded above 1273K was higher than tantalium or zirconium base metal in spite of absence of intermetallic compound. The growth of reaction layer at the stainless steel and tantalium interface and at the tantalium and zirconium interface was conforming a parabolic low when that was isothermally heated after hot roll bonding, and the growth rate was almost same as that of static diffusion bonding without using hot roll bonding process. It is estimated that the strain caused by hot roll bonding gives no effect on the growth of reaction layer. It was confirmed that the dissimilar joint of zirconium and stainless steel with insert of tantalium having the sound bonding interface were obtained at the suitable bonding temperature of 1173K by the usage of the newly developed hot roll bonding process. (author)

  7. Precision grinding of microarray lens molding die with 4-axes controlled microwheel

    OpenAIRE

    Yuji Yamamoto, Hirofumi Suzuki, Takashi Onishi1, Tadashi Okino and Toshimichi Moriwaki

    2007-01-01

    This paper deals with precision grinding of microarray lens (fly eye) molding die by using a resinoid bonded diamond wheel. An ultra-precision grinding system of microarray lens molding die and new truing method of resinoid bonded diamond wheel were developed. In this system, a grinding wheel was four-dimensionally controlled with 1 nm resolution by linear scale feedback system and scanned on the workpiece surface. New truing method by using a vanadium alloy tool was developed and its perform...

  8. Effect of Cooling Environment on Grinding Performance of Nickel Based Superalloy Inconel 718

    OpenAIRE

    Pawade, Raju S.; Arvind Chavan; Pankaj Chitalkar; Sandeep Huddedar

    2012-01-01

    The study presents the experimental investigation of surface grinding of superalloy Inconel 718. The grinding performance in terms of grinding force, surface roughness and surface topography were examined by conducting statistical experiments. The parameters that have been chosen as control factors are: table speed, infeed, grit size and the type of lubricant. An L27 orthogonal array experiments were conducted. The results show that the grit size and infeed are the most significant para...

  9. The use of cylindrical grinding to produce a martensitic structure on the surface of 4340 Steel

    OpenAIRE

    André Lima; Luiz Sérgio Gâmbaro; Milton Vieira Junior; Elesandro Antonio Baptista

    2011-01-01

    Grinding is one of the most widely used manufacturing processes and, in the last few decades, has developed considerably. An example of these developments is hardening by grinding, an operation that is being studied to provide an option to the conventional hardening processes. This study presents the use of a cylindrical grinding process to produce a martensitic structure on the surface of SAE 4340 steel workpieces, and aims at adjusting the parameters of this process. To do much, a set of ex...

  10. Modelling of fracture wear in vitrified cBN grinding wheels

    OpenAIRE

    Jackson, M. J.

    2007-01-01

    Purpose: The paper describes modelling of fracture wear in vitrified cBN grinding wheels.Design/methodology/approach: The approach used in the paper is based on using finite elements to model fracture wear processes in vitrified cBN grinding wheels. The approach used models fracture wear processes and ignores abrasive wear of the abrasive grains.Findings: The findings show that during grinding the grain is subjected to forces that create fracture initiation zones in the sharp abrasive grains...

  11. ANALYSIS OF THE SURFACE PROFILE AND ITS MATERIAL SHARE DURING THE GRINDING INCONEL 718 ALLOY

    Directory of Open Access Journals (Sweden)

    Martin Novák

    2015-05-01

    Full Text Available Grinding is still an important method for surface finishing. At FPTM JEPU research, which deals with this issue is conducted. Experiments are carried out with grinding various materials under different conditions and then selected components of the surface integrity are evaluated. They include roughness Ra, Rm and Rz, Material ratio curve (Abbott Firestone curve and also the obtained roundness. This article deals with grinding nickel Inconel 718 alloy, when selected cutting grinding conditions were used and subsequently the surface profile and the material ratio curve were measured and evaluated.

  12. Research on Optimization of Plunge Centerless Grinding Process using Genetic Algorithm and Response Surface Method

    Directory of Open Access Journals (Sweden)

    Phan Bui Khoi

    2015-03-01

    Full Text Available This paper presents the research on optimization of plunge centerless grinding process when grind 20X – carbon infiltration steel (?OCT standard - Russia to achieve minimum of roundness error value. The input parameters are center height angle of the workpiece ( ? , longitudinal grinding wheel dressing feed-rate ( Ssd , plunge feed-rate ( k S and control wheel velocity ( dd v . Using the result of 29 runs in Central Composite Design matrix to given the second order roundness error model. Genetic algorithm and Response surface method were used to focus on determination of optimum centerless grinding above parameters for minimization of roundness error for each methods.

  13. Hot rolling of intermetallics FeAl phase based alloys

    Directory of Open Access Journals (Sweden)

    G. Niewielski

    2008-02-01

    Full Text Available Purpose: The one of major problem restricting universal employment of intermetallic phase base alloy istheir low plasticity which leads to hampering their development as construction materials. The following workconcentrates on possibilities to form through rolling process the alloys with various aluminium content.Design/methodology/approach: After casting and annealing, alloy specimens were subjected to axialsymmetriccompression at temperatures ranging from 900 to 1200°C at 10 s-1 strain rates. In order to analyse theprocesses which take place during deformation, the specimens after deformation were intensely cooled with water.Structural examination was carried out using light microscopy. The process was conducted on the K -350 quartorolling mill used for hot rolling of flat products. The process was conducted in some stages in at temperaturesranging from 1200-900°C:Findings: The research carried out enabled the understanding of the phenomena taking place during hot rolling ofthe investigated alloy. An alloy with 38%at. aluminium concentration can be plastically formed at a temperature of upto 900°C, which has been also confirmed in plastometric studies conducted in the form of hot compression tests.Research limitations/implications:Practical implications: The obtained sheets can be used as constructional elements working in complex stressfields, at a high temperature and corrosive environmentsOriginality/value: The tests have shown that it is possible to form the investigated alloys through rolling processingonly where shields are applied. Rolling of the alloys without shields led to the occurrence of a grid of cracks.

  14. Tuning the length dispersion of multi-walled carbon nanotubes by ball milling

    OpenAIRE

    László Forró; Richard Gaal; Claudio Grimaldi; Marijana Mioni?; Primož Rebernik Ribi?; Rita Smajda; Arnaud Magrez

    2013-01-01

    The statistical analysis of the length distribution of catalytic chemical vapour deposition synthesized multi-walled carbon nanotubes cut by planetary ball milling is reported. The nanotube lengths follow a log-normal distribution in a broad range of grinding time and rotational speed. We show that the scale parameter of the distribution, which equals the mean of the natural logarithm of the tube lengths, decreases linearly with the product of the duration time and the rotational speed. This ...

  15. Investigation of the maintenance organisation for hot rolling mills

    OpenAIRE

    Pretorius, P. K.; Visser, J. K.

    2001-01-01

    ENGLISH ABSTRACT: Production systems have undergone dramatic changes in recent years. Many companies have implemented new technologies such as flexible manufacturing systems. There is therefore a shift in focus to maintenance and the effective management thereof. Maintenance is a dynamic activity and is comprised of a large number of interacting variables. An effective maintenance organisation is required to control these variables .
    This paper discusses the building of a ...

  16. GRCop-84 Rolling Parameter Study

    Science.gov (United States)

    Loewenthal, William S.; Ellis, David L.

    2008-01-01

    This report is a section of the final report on the GRCop-84 task of the Constellation Program and incorporates the results obtained between October 2000 and September 2005, when the program ended. NASA Glenn Research Center (GRC) has developed a new copper alloy, GRCop-84 (Cu-8 at.% Cr-4 at.% Nb), for rocket engine main combustion chamber components that will improve rocket engine life and performance. This work examines the sensitivity of GRCop-84 mechanical properties to rolling parameters as a means to better define rolling parameters for commercial warm rolling. Experiment variables studied were total reduction, rolling temperature, rolling speed, and post rolling annealing heat treatment. The responses were tensile properties measured at 23 and 500 C, hardness, and creep at three stress-temperature combinations. Understanding these relationships will better define boundaries for a robust commercial warm rolling process. The four processing parameters were varied within limits consistent with typical commercial production processes. Testing revealed that the rolling-related variables selected have a minimal influence on tensile, hardness, and creep properties over the range of values tested. Annealing had the expected result of lowering room temperature hardness and strength while increasing room temperature elongations with 600 C (1112 F) having the most effect. These results indicate that the process conditions to warm roll plate and sheet for these variables can range over wide levels without negatively impacting mechanical properties. Incorporating broader process ranges in future rolling campaigns should lower commercial rolling costs through increased productivity.

  17. Deaths and tumors among workers grinding stainless steel.

    Science.gov (United States)

    Svensson, B G; Englander, V; Akesson, B; Attewell, R; Skerfving, S; Ericson, A; Möller, T

    1989-01-01

    This study examined a cohort of 1,164 males who, during the period 1927-1981, had been employed for 3 months or more in an industry that produced objects from stainless steel. These workers were exposed to the dust of grinding materials, grinding agents, and stainless steel. From 1975 to 1980, measurements of the total dust in the workroom air have shown levels of about one mg/m3 (consisting of chromium at about 0.1 mg/m3 and nickel at about 0.05 mg/m3) during grinding and several mg/m3 (chromium at about 0.01 mg/m3 and nickel at about 0.005 mg/m3) during polishing. Before 1950, the concentrations were probably considerably higher. Compared to a local reference population, a decrease in mortality (63 observed deaths, standardized mortality (SMR) = 0.79, 95% confidence limits CL = 0.61, 1.01) took place during the 1951-1983 observation period among 318 subjects who had been employed for at least five years, allowing a latency period of at least 20 years. Mortality from cancer of the colon/rectum increased (observed deaths = 6, SMR = 2.47, CL = 0.97, 5.58). The mortality from nonmalignant pulmonary disease did not increase (SMR = 0.29, CL = 0.01, 1.81). During the observation period (1958-1983), there was no significant overall excess of tumors (observed cases = 33, standardized morbidity [SMR] = 1.09, CL = 0.76, 1.54). However, tumor morbidity of the colon/rectum (observed 11, SMR = 2.83, CL = 1.47, 5.19) significantly increased. There were no cases of respiratory cancer (expected 4.7, CL = 0, 0.21). Thus, the results indicate an increased risk of intestinal cancer.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2929608

  18. Application of cryogenic grinding to achieve homogenization of transuranic wastes

    International Nuclear Information System (INIS)

    This paper describes work done at Los Alamos National Laboratory (LANL) in collaboration with the Department of Energy Rocky Flats Field Office (DOE/RFFO) and with the National Institute of Standards and Technology (NIST), Boulder, Colorado. Researchers on this project have developed a method for cryogenic grinding of mixed wastes to homogenize and, thereby, to acquire a representative sample of the materials. There are approximately 220,000 waste drums owned by the Rocky Flats Environmental Technology Site (RFETS)-50,000 at RFETS and 170,000 at the Idaho National Engineering Laboratory. The cost of sampling the heterogeneous distribution of waste in each drum is prohibitive. In an attempt to produce a homogeneous mixture of waste that would reduce greatly the cost of sampling, researchers at NIST and RFETS are developing a cryogenic grinder. The Los Alamos work herein described addresses the implementation issues of the task. The first issue was to ascertain whether samples of the open-quotes small particleclose quotes mixtures of materials present in the waste drums at RFETS were representative of actual drum contents. Second, it was necessary to determine at what temperature the grinding operation must be performed in order to minimize or to eliminate the release of volatile organic compounds present in the waste. Last, it was essential to evaluate any effect the liquid cryogen might have on the structural integrity and ventilation capacity of the glovebox system. Results of this study showed that representative samples could be and had been obtained, that some release of organics occurred below freezing because of sublimation, and that operation of the cryogenic grinding equipment inside the glovebox was feasible

  19. In-process EDM truing to generate complex contours on metal-bond, superabrasive grinding wheels for precision grinding structural ceramics

    International Nuclear Information System (INIS)

    The demand and use of precision grinding of structural ceramics continue to increase as the worldwide advanced ceramic industry surpasses $20 billion is sales. Included in this industry are engineering structural ceramics, electronic ceramics, bioceramics and others. These materials are used in applications such as engine components, casting and extrusion dies, bearings, medical implants, nozzles, thermal insulators, and more. Along with the variety of ceramic applications comes a broad range of precision requirements, which in turn leads to various required processes to accommodate a spectrum of specifications. A process for grinding ceramic components to micrometer tolerances was employed and further developed at Lawrence Livermore National Laboratory for two separate grinding projects

  20. The Influence of the Shape of Grooves on the Intensity of Closing Axial Material Discontinuities During Rolling

    Directory of Open Access Journals (Sweden)

    Sobczak K.

    2015-04-01

    Full Text Available The article discusses the influence of rolling in the newly designed slitting-bending grooves on closing internal material discontinuities in continuous ingots. The defects located in the axial area of a strand, i.e. axial porosity and contraction cavity, were analysed. Numerical and experimental studies of the rolling process of flat bars for feedstock with marked materials discontinuities simulating actual defects occurring in an ingot were conducted. For comparison purposes, rolling of feedstock with discontinuities in traditional grooves was conducted. The numerical simulations were carried out using the Forge 2008¯software programme. The experimental studies were conducted in a D150 laboratory rolling mill. In the research, the S355J2G3 structural steel and lead were used. Distributions of temperature, intensity of deformation and stress in a cross-section of strands after rolling were analysed. Changes in the surface areas of the discontinuities in feedstock after rolling in shape and traditional grooves were examined.

  1. Walk and roll robot

    Science.gov (United States)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2011-01-01

    A mobile robotic unit features a main body, a plurality of legs for supporting the main body on and moving the main body in forward and reverse directions about a base surface, and a drive assembly. According to an exemplary embodiment each leg includes a respective pivotal hip joint, a pivotal knee joint, and a wheeled foot adapted to roll along the base surface. Also according to an exemplary embodiments the drive assembly includes a motor operatively associated with the hip and knee joints and the wheeled foot for independently driving pivotal movement of the hip joint and the knee joint and rolling motion of the wheeled foot. The hip joint may include a ball-and-socket-type joint interconnecting top portion of the leg to the main body, such that the hip joint is adapted to pivot said leg in a direction transverse to a forward-and-reverse direction.

  2. Optimization of mill performance by using online ball and pulp measurements

    Scientific Electronic Library Online (English)

    B., Clermont; B., de Haas.

    2010-03-01

    Full Text Available Ball mills are usually the largest consumers of energy within a mineral concentrator. Comminution is responsible for 50% of the total mineral processing cost. In today's global markets, expanding mining groups are trying to optimize mill performances. Since comminution is concerned with liberating v [...] aluable minerals for recovery in the separation process, it is crucial to run the mills at the best operating conditions which lead to good liberation at competitive throughputs with minimum costs (energy and wear). The high availability of the equipment is also essential to maximize production and profit. To reach this key objective, continuous and reliable information about the mill operation is vital. An innovative tool which can deliver information about in-mill dynamics has been developed by Magotteaux. It can provide online and accurate measurements of the degree of grinding ball fill and pulp position for timely decision making and actions. This tool could be used on its own or linked to an automatic grinding ball loading system named Magoload . Therefore, ball load could be kept constant by using direct measurement. This article describes the Sensomag and presents some of the major improvements that can be achieved with it. Some other promising avenues are still to be explored.

  3. Analysis on Large Deformation Compensation Method for Grinding Machine

    Directory of Open Access Journals (Sweden)

    Wang Ya-jie

    2013-08-01

    Full Text Available The positioning accuracy of computer numerical control machines tools and manufacturing systems is affected by structural deformations, especially for large sized systems. Structural deformations of the machine body are difficult to model and to predict. Researchs for the direct measurement of the amount of deformation and its compensation are farly limited in domestic and overseas,not involved to calculate the amount of deformation compensation. A new method to compensate large deformation caused by self-weight was presented in the paper. First of all, the compensation method is summarized; Then,static force analysis was taken on the large grinding machine through APDL(ANSYS Parameter Design Language. It could automatic extract results and form data files, getting the N points displacement in the working stroke of mechanical arm. Then, the mathematical model and corresponding flat rectangular function were established. The conclusion that the new compensation method is feasible was obtained through the analysis of displacement of N points. Finally, the MATLAB as a tool is used to calculate compensate amount and the accuracy of the proposed method is proved. Practice shows that the error caused by large deformatiion compensation method can meet the requirements of grinding.  

  4. Effects of imbalance and geometric error on precision grinding machines

    Energy Technology Data Exchange (ETDEWEB)

    Bibler, J.E.

    1997-06-01

    To study balancing in grinding, a simple mechanical system was examined. It was essential to study such a well-defined system, as opposed to a large, complex system such as a machining center. The use of a compact, well-defined system enabled easy quantification of the imbalance force input, its phase angle to any geometric decentering, and good understanding of the machine mode shapes. It is important to understand a simple system such as the one I examined given that imbalance is so intimately coupled to machine dynamics. It is possible to extend the results presented here to industrial machines, although that is not part of this work. In addition to the empirical testing, a simple mechanical system to look at how mode shapes, balance, and geometric error interplay to yield spindle error motion was modelled. The results of this model will be presented along with the results from a more global grinding model. The global model, presented at ASPE in November 1996, allows one to examine the effects of changing global machine parameters like stiffness and damping. This geometrically abstract, one-dimensional model will be presented to demonstrate the usefulness of an abstract approach for first-order understanding but it will not be the main focus of this thesis. 19 refs., 36 figs., 10 tables.

  5. Microstructural and reliability in grinding of silicon nitride

    International Nuclear Information System (INIS)

    A sintered Si3N4 matrix has been characterized by TEM. The film thickness distribution of Si3N4 was measured by high resolution transmission electron microscopy (HREM). Surface grinding is performed on two table speeds of 0.08 and 0.25 m s-1 with different depth of cut. The ground surfaces were observed with scanning electron microscopy (SEM). The surface texture was found to have greater dependence on depth of cut and table speed. The surface roughness is improved after smaller depth of cut. The flexural strength of ground specimens were measured by four-point flexure tests. The effect of depth of cut during grinding on the flexural strength and reliability of silicon nitride is investigated. The large depth of cut of 30 ?m/pass resulted in a further decreased in strength of 540 MPa and a Weibull modulus of 7.5. When the depth of cut of 5 ?m/pass were subjected to the ground specimens, the average strength was increased to 670 MPa and Weibull modulus to 9.1

  6. Dry-grinded ultrafine cements hydration. physicochemical and microstructural characterization

    Scientific Electronic Library Online (English)

    Foteini, Kontoleontos; Petros, Tsakiridis; Apostolos, Marinos; Nikolaos, Katsiotis; Vasileios, Kaloidas; Margarita, Katsioti.

    2013-04-01

    Full Text Available The aim of the present research work was the evaluation of the physicochemical and microstructural properties of two ultrafine cements, produced by dry grinding of a commercial CEM I 42.5N cement. The effect of grinding on particle size distribution was determined by laser scattering analyzer. All c [...] ements were tested for initial and final setting times, consistency of standard paste, soundness, flow of normal mortar and compressive strengths after 1, 2, 7 and 28 days. The effect of the fineness on the heat of hydration was also investigated. The hydration products were determined by X-ray diffraction analysis and by Fourier transform infrared spectroscopy, at 1, 2, 7 and 28 days. The microstructure of the hardened cement pastes and their morphological characteristics were examined by scanning electron microscopy. Porosity and pore size distribution were evaluated by mercury intrusion porosimetry. The effects of greater fineness on compressive strengths were evident principally at early ages. After the first 24 hours of hydration, the compressive strength of the finest cements was about 3 times higher (over 48 MPa) than the corresponding of CEM I 42.5N (15.1 MPa).

  7. Speed roll laws influence in a Ring Rolling process

    OpenAIRE

    Giorleo, Luca; Ceretti, Elisabetta; Giardini, Claudio

    2013-01-01

    Ring Rolling is a complex hot forming process used for the production of shaped rings, seamless and axis symmetrical workpieces. The main advantage of workpieces produced by ring rolling, compared to other technological processes, is given by the size and orientation of grains, especially on the worked surface which give to the final product excellent mechanical properties. In this process different rolls (Idle, Axial, Guide and Driver) are involved in generating the desired ring shape. Becau...

  8. Grooved roll for a high speed twin roll caster

    OpenAIRE

    T. Haga; Hirooka, K; Watari, H; S. Kumai

    2008-01-01

    Purpose: Purpose of this paper is investigation of the effect of roll-surface on the strip-surface. Improvement ofsmall cracks on the strip-surface was tried and effect of groove at the roll surface on the strip surface was shown.Design/methodology/approach: Method used in the present study was high speed twin roll caster withgrooved roll. Two kinds of grooves were used: one was parallel groove and the other was cross groove machinedby knurling and bite attached to a lathe.Findings: Findings ...

  9. The effect of grinding on magnetic properties of agglomereted MnFe2O4 nanoparticles

    International Nuclear Information System (INIS)

    The effects of grinding on interparticle magnetic interactions for an ensemble of agglomerated MnFe2O4 nanoparticles have been studied. Structural analyses showed that by grinding the samples, a small variation in size of crystallites and lattice strain will occur. ac Magnetic susceptibility measurements under different conditions and spin dynamics analysis suggest that freezing temperature is frequency dependent and it is in good agreement with critical slowing down model. This is an indication that these nanoparticles have superspin glass behavior. The estimated z? and ?0 parameters using critical slowing down model show that by increasing the grinding time the interaction between nanoparticles decreases. ac Susceptibility measurements in cooling and heating process show a thermal hysteresis. The thermal hysteresis decreased by increasing the grinding time. Also, the thermal hysteresis is frequency dependent and it increased as frequency decreased. These results showed that interparticle interactions such as dipole-dipole and exchange interactions between nanoparticles become weaker by grinding. - Highlights: ? We studied the effects of grinding on interparticle interactions of MnFe2O4 nanoparticles. ? Critical slowing model used to estimate the interparticle interaction strength. ? The results showed interparticle interactions become weaker by grinding. ? Ac Susceptibility shows the irreversibility ofity shows the irreversibility of spins decreased by grinding.

  10. Effect of Milling Time on Al-Fe-Cr-20 Wt. % Al2O3composite Prepared Through Ball Milling

    Directory of Open Access Journals (Sweden)

    Hameedur Rehman Khan

    2014-07-01

    Full Text Available One of the main challenges towards achieving a homogeneous distribution of the ceramic phase in the metal matrix composites is agglomeration of the reinforcement particles. Mechanical alloying is among the most important processing techniques used for manufacturing of metal matrix composites (MMCs.An attempt was made to synthesize Al-Fe-Cr-Al2O3composites synthesized through mechanical alloying. Al2O3 is used as reinforcement. Ethanol (5 wt. % has been used as a process control agent (PCA. Mechanical alloying is carried out in a conventional ball mill using stainless steel grinding media at 115 rpm in the argon environment for 5h, 10h and 15h. The ball to powder weight ratio was maintained at 20:1. The characterization of the ball milled powder was followed by scanning electron microscopy (SEM. Showed the formation of a homogeneous phase for all compositions after milling for 15 h. XRD patterns were recorded for the milled powders, and analyzed using Williamson–Hall method and Scherrer’s equation to determine the lattice strain and grain size.EDX is performed to check the contamination of composites during the mechanical alloying.XRD is used to study structural evolution of synthesized aluminium composite. Effect of milling time is investigated on synthesized Al-Fe-Cr-20 wt. % Al2O3 composites.

  11. Investigation of the Formation Process of Two Piracetam Cocrystals during Grinding

    Directory of Open Access Journals (Sweden)

    Keith Gordon

    2011-10-01

    Full Text Available Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e.,piracetam-citric acid and piracetam-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to progress via an amorphous intermediate stage, which was more evident for the piracetam-citric acid than for the piracetam-tartaric acid cocrystal. It was shown that liquid-assisted grinding led to faster cocrystal formation than dry grinding, which may be explained by the higher transformation rate due to the presence of liquid. The cocrystal formation rate did not depend on the applied polymorphic form of the piracetam and no polymorphic cocrystals were obtained.

  12. Investigation of the formation process of two piracetam cocrystals during grinding

    DEFF Research Database (Denmark)

    Rehder, Sönke; Klukkert, Marten

    2011-01-01

    Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e.,piracetam-citric acid and piracetam-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to progress via an amorphous intermediate stage, which was more evident for the piracetam-citric acid than for the piracetam-tartaric acid cocrystal. It was shown that liquid-assisted grinding led to faster cocrystal formation than dry grinding, which may be explained by the higher transformation rate due to the presence of liquid. The cocrystal formation rate did not depend on the applied polymorphic form of the piracetam and no polymorphic cocrystals were obtained.

  13. Effect of Cooling Environment on Grinding Performance of Nickel Based Superalloy Inconel 718

    Directory of Open Access Journals (Sweden)

    Raju S. Pawade

    2012-01-01

    Full Text Available The study presents the experimental investigation of surface grinding of superalloy Inconel 718. The grinding performance in terms of grinding force, surface roughness and surface topography were examined by conducting statistical experiments. The parameters that have been chosen as control factors are: table speed, infeed, grit size and the type of lubricant. An L27 orthogonal array experiments were conducted. The results show that the grit size and infeed are the most significant parameters on surface roughness Ra measured across the table feed direction. The interaction effect between lubricant and grit size is relatively important as compared to the individual effect of the latter variable. As far as the grinding forces are concerned, the grit size and table speed have largest contribution among the chosen parameters. SEM (Semester examination revealed the flaws such as abrasion marks, smeared layers and micro-particle deposits on the surfaces produced in grinding.

  14. Measurement of Force Components and Ra Surface Roughness Parameter During Grinding Titanium Alloy

    Directory of Open Access Journals (Sweden)

    Grdulska A.

    2014-10-01

    Full Text Available The paper deals with the measurements of selected parameters during grinding process of aerospace industry alloy. Grinding is one of the most important methods of shaping machine elements. As a result of grinding with high dimensional and shape accuracy as well as with the expected parameters describing the state of the surface layer (SL should be obtained. Grinding difficult to machine materials used in the aerospace industry is an issue currently being examined by various research centres. An excellent example is the analysis of the grinding process of titanium alloys, as these materials have very poor machinability due to the tendency to adherence to abrasive materials, low thermal conductivity, high strength and compliance at elevated temperatures, which may adversely impact on the quality of SL. A number of factors influence on shaping SL. Worth mentioning are mechanical and thermal phenomena, as well as the type of cutting fluid and abrasive materials

  15. Automatic detection of thermal damage in grinding process by artificial neural network

    Directory of Open Access Journals (Sweden)

    Dotto Fábio Romano Lofrano

    2003-01-01

    Full Text Available This work aims to develop an intelligent system for detecting the workpiece burn in the surface grinding process by utilizing a multi-perceptron neural network trained to generalize the process and, in turn, obtnaing the burning threshold. In general, the burning occurrence in grinding process can be detected by the DPO and FKS parameters. However, these ones were not efficient at the grinding conditions used in this work. Acoustic emission and electric power of the grinding wheel drive motor are the input variable and the output variable is the burning occurrence to the neural network. In the experimental work was employed one type of steel (ABNT-1045 annealed and one type of grinding wheel referred to as TARGA model ART 3TG80.3 NVHB.

  16. Analysis of the influence of infeed rate and cutting fluid on cylindrical grinding processes using a conventional wheel

    OpenAIRE

    Bianchi Eduardo Carlos; Franzo Carolina Grimm; Aguiar Paulo Roberto de; Catai Rodrigo Eduardo

    2004-01-01

    New worldwide trends such as globalization have rendered grinding processes increasingly important for industry, making it essential to perform in-depth studies of variations in grinding process parameters in the pursuit of greater cost effectiveness. This paper presents a comparative analysis of three different infeed rates, using a conventional grinding wheel on quenched and tempered D2 steel workpieces. Higher infeed rates are known to be correlated with shorter grinding times, rendering t...

  17. Performance of direct and reverse Samarco grinding circuits / Desempenho dos circuitos de moagem direto e inverso da Samarco

    Scientific Electronic Library Online (English)

    Andreia Carolina, Rosa; Homero, Delboni Jr.

    2014-06-01

    Full Text Available Os aspectos operacionais entre as configurações de circuito fechado de moagem em moinhos de bolas, quais sejam, os circuitos direto e inverso, foram analisados comparativamente. Foram realizadas amostragens no circuito industrial de moagem primária do Concentrador I de Germano, operando sob ambas as [...] configurações, além de serem analisados os dados históricos industriais dos Concentradores I e II. Por fim, foram realizados ensaios de moagem em laboratório, simulando ambas as condições. A comparação entre os históricos dos dados industriais dos Concentradores I (operando sob circuito inverso) e do Concentrador II (operando sob circuito direto) mostrou um histórico consistente em que o circuito do Concentrador II apresenta menor consumo energético por tonelada de material gerado abaixo da malha de controle do circuito. Esses resultados foram diferentes daqueles obtidos a partir das amostragens realizadas no circuito industrial da Samarco, os quais indicaram melhor desempenho do circuito inverso. A diferença foi atribuída à etapa de classificação, cujo desempenho determina a alteração ou até mesmo anula os benefícios, conforme demonstram os resultados de simulação posteriores. Abstract in english This paper compares the performance associated with both direct and reverse ball mill closed circuit configurations. Survey campaigns were carried out in both Samarco Mineração industrial plants, i.e., Concentrator I and Concentrator II. The former is equipped with a reverse-configured ball mill clo [...] sed grinding circuit, while the latter is equipped with ball mills under a direct closed circuit. The study consisted of laboratory jar tests, as well as comparisons between historical data obtained for both industrial plants. Comparisons based on historical data indicated that Concentrator II, configured in a direct mode, exhibited a better performance than that of Concentrator I. Such a conclusion is in contrast with the results obtained from survey campaigns, which indicated a better performance for the reverse configuration. Such a difference was determined by the performance of the classification stage, carried out in cyclones, as demonstrated by simulations conducted on the basis of previously calibrated models.

  18. Innovative grinding wheel design for cost-effective machining of advanced ceramics. Phase I, final report

    Energy Technology Data Exchange (ETDEWEB)

    Licht, R.H.; Ramanath, S.; Simpson, M.; Lilley, E.

    1996-02-01

    Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics. This program was a cooperative effort involving three Norton groups representing a superabrasive grinding wheel manufacturer, a diamond film manufacturing division and a ceramic research center. The program was divided into two technical tasks, Task 1, Analysis of Required Grinding Wheel Characteristics, and Task 2, Design and Prototype Development. In Task 1 we performed a parallel path approach with Superabrasive metal-bond development and the higher technical risk, CVD diamond wheel development. For the Superabrasive approach, Task 1 included bond wear and strength tests to engineer bond-wear characteristics. This task culminated in a small-wheel screening test plunge grinding sialon disks. In Task 2, an improved Superabrasive metal-bond specification for low-cost machining of ceramics in external cylindrical grinding mode was identified. The experimental wheel successfully ground three types of advanced ceramics without the need for wheel dressing. The spindle power consumed by this wheel during test grinding of NC-520 sialon is as much as to 30% lower compared to a standard resin bonded wheel with 100 diamond concentration. The wheel wear with this improved metal bond was an order of magnitude lower than the resin-bonded wheel, which would significantly reduce ceramic grinding costs through fewer wheel changes for retruing and replacements. Evaluation of ceramic specimens from both Tasks 1 and 2 tests for all three ceramic materials did not show evidence of unusual grinding damage. The novel CVD-diamond-wheel approach was incorporated in this program as part of Task 1. The important factors affecting the grinding performance of diamond wheels made by CVD coating preforms were determined.

  19. Electron spin resonance and thermoluminescence in powder form of clear fused quartz: effects of grinding

    International Nuclear Information System (INIS)

    Clear fused quartz (CFQ) tubes were powdered either manually by using a mortar and pestle (for coarse production) or mechanically, using a micronising mill (for fine production). A high and multisignal electron spin resonance (ESR) background was found in the fine powder even after annealing it at 900 deg. C for 20 min. In the case of the coarse powder, the signal (ESR background) varied inversely with particle size and was quite high for particle sizes lower than 38 ?m. In a subsidiary experiment, using fine SiO2 powder (99.8% pure, with the particle size of ?0.007 ?m), manufactured by using flame hydrolysis, only a weak background signal was found. The 60Co gamma-ray irradiated powders (?22 Gy) were subjected to ESR analysis or thermoluminescence (TL) readout. The ESR intensity of the coarse powder varied directly with particle size. Thus, the intensity for a particle size of 20-38 ?m was very low and almost the same as the unirradiated intensity. In TL readout the results were the opposite: the TL intensity of the coarse powder varied inversely with the particle size down to 38 ?m, after which it decreased with decreasing particle size of the material. The fine powder, produced by grinding the CFQ tubes, was insensitive to gamma-rays (at least at doses of up to 50 Gy); but for the flame hydrolysis SiO2 the situation was the opposite. The minimum detectable dose (MDD) for the CFQ in powder form using ESR was ?2 Gy, which isrm using ESR was ?2 Gy, which is ?2 times higher than that for the bulk form, while the MDD for the powder using TL was ?20 ?Gy, which is ?2 times lower than that for the bulk form of the material

  20. 7.SP Rolling Twice

    Science.gov (United States)

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: A fair six-sided die is rolled twice. What is the theoretical probability that the first number that comes up is greater than or equal to the second nu...

  1. Tuning Swiss roll metamaterials

    International Nuclear Information System (INIS)

    The 'Swiss roll' metamaterial is well suited to operation in the radiofrequency range because it has a low resonant frequency, a strong magnetic response and is electrically very small. However, the elements have to be individually produced, leading to significant variation in the resonant frequency. It is therefore necessary to tune the elements to a target frequency. Three methods for achieving this are described: attaching capacitatively coupled sleeves or discrete capacitors for static tuning, and using a varactor diode to provide electrically controllable tuning. In the last case, the switching time is found to be <1 ms, making dynamic tuning a real possibility.

  2. Investigations upon the indefinite rolls quality assurance in multiple regression analysis

    International Nuclear Information System (INIS)

    The rolling rolls quality has been enhanced mainly due to the improvements of the chemical compositions of rolls materials. The realization of an optimal chemical composition can constitute a technical efficient mode to assure the exploitation properties, the material from which the rolling mills rolls are manufactured having a higher importance in this sense. This paper continues to present the scientifically results of our experimental research in the area of the rolling rolls. The basic research contains concrete elements of immediate practical utilities in the metallurgical enterprises, for the quality improvements of rolls, having in last as the aim the durability growth and the safety in exploitation. This paper presents an analysis of the chemical composition, the influences upon the mechanical properties of the indefinite cast iron rolls. We present some mathematical correlations and graphical interpretations between the hardness (on the working surface and on necks) and the chemical composition. Using the double and triple correlations which is really helpful in the foundry practice, as it allows us to determine variation boundaries for the chemical composition, in view the obtaining the optimal values of the hardness. We suggest a mathematical interpretation of the influence of the chemical composition over the hardness of these indefinite rolling rolls. In this sense we use the multiple regression analysis which can be an important statistical tool for the be an important statistical tool for the investigation of relationships between variables. The enunciation of some mathematically modeling results can be described through a number of multi-component equations determined for the spaces with 3 and 4 dimensions. Also, the regression surfaces, curves of levels and volumes of variations can be represented and interpreted by technologists considering these as correlation diagrams between the analyzed variables. In this sense, these researches results can be used in the engineers collectives of the foundries and the rolling mills sectors, for quality assurances of rolls as far back as phase of production, as well as in exploitation of these, what lead to, inevitably, to the quality assurance of produced laminates. (Author) 16 refs.

  3. Investigations upon the indefinite rolls quality assurance in multiple regression analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, I.

    2012-11-01

    The rolling rolls quality has been enhanced mainly due to the improvements of the chemical compositions of rolls materials. The realization of an optimal chemical composition can constitute a technical efficient mode to assure the exploitation properties, the material from which the rolling mills rolls are manufactured having a higher importance in this sense. This paper continues to present the scientifically results of our experimental research in the area of the rolling rolls. The basic research contains concrete elements of immediate practical utilities in the metallurgical enterprises, for the quality improvements of rolls, having in last as the aim the durability growth and the safety in exploitation. This paper presents an analysis of the chemical composition, the influences upon the mechanical properties of the indefinite cast iron rolls. We present some mathematical correlations and graphical interpretations between the hardness (on the working surface and on necks) and the chemical composition. Using the double and triple correlations which is really helpful in the foundry practice, as it allows us to determine variation boundaries for the chemical composition, in view the obtaining the optimal values of the hardness. We suggest a mathematical interpretation of the influence of the chemical composition over the hardness of these indefinite rolling rolls. In this sense we use the multiple regression analysis which can be an important statistical tool for the investigation of relationships between variables. The enunciation of some mathematically modeling results can be described through a number of multi-component equations determined for the spaces with 3 and 4 dimensions. Also, the regression surfaces, curves of levels and volumes of variations can be represented and interpreted by technologists considering these as correlation diagrams between the analyzed variables. In this sense, these researches results can be used in the engineers collectives of the foundries and the rolling mills sectors, for quality assurances of rolls as far back as phase of production, as well as in exploitation of these, what lead to, inevitably, to the quality assurance of produced laminates. (Author) 16 refs.

  4. Preliminary study of sintering of metallic niobium processed for mechanical milling; Estudo preliminar da sinterizacao de niobio metalico processado por moagem de alta energia

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, H.M.; Vurobi Junior, S.; Cintho, O.M., E-mail: lenatamura@interponta.com.b [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil); Sandim, H.R.Z.; Leite, G.S. [Universidade de Sao Paulo (EEL/USP), Lorena, SP (Brazil). Escola de Engenharia

    2010-07-01

    In present study was preliminary study of mechanical milling influence on preparing of metallic niobium powder for sintering. Sample of metallic niobium in powder passing in sieve no. 635 mesh was processed by mechanical milling in SPEX mill for 8 hours using power grinding of 7:1 and a nitrogen atmosphere. The powder was annealed at different temperatures, 900 deg C, 1000 deg C, 1100 deg C and 1200 deg C for 1 hour in an atmosphere of hydrogen and argon to study their crystallization, which then were formed into blank for analysis of the curves compressibility. These samples were also subjected to x-ray diffraction in that their data were compared between the annealing temperatures. We also evaluate the compressibility curves of niobium samples with and without grinding these samples were subjected to x-ray diffraction and fluorescence. (author)

  5. Examination of cold leg roll transition zones at Ringhals 2

    International Nuclear Information System (INIS)

    Ringhals 2 is a PWR of Westinghouse design put into operation in 1974. The unit has three Westinghouse Series 51 steam generators with mill annealed Alloy 600 tubing. The unit was operated for a few months at low power with a phosphate secondary water chemistry. This was changed in September 1974 to all volatile treatment (AVT). In 1981, cracks on the primary side at roll transition zones on the hot leg side were detected. Examination of 15 tubes removed in 1983 revealed that a majority of the roll transition zones on the hot leg side have such cracks. This examination established the importance of carbide distribution and geometry of roll transitions on this type of cracking. In 1984, five tubes were removed from the cold leg side as part of a life expectancy study. Examination of these tubes revealed primary side cracks in the roll transition zone on three of the five tubes. The microstructural characterization of the tube materials established that in all five tubes the carbide distribution was intragranular. The insides of the tube walls have been examined well away from the expanded part of the tubes. Intergranular attack was found on the hot leg. This attack is about one grain diameter deep and on the cold leg side the attack is very shallow. Nevertheless, the observations show a very slow intergranular attack on the primary side of the tubes

  6. Roll Back Malaria Partnership

    Science.gov (United States)

    With all the attention paid to a wide range of diseases that affect various populations around the world, some may still be surprised to learn that relatively little money is spent researching malaria. Bill Gates recently gave $258 million to help research this disease, and in doing so, his efforts will complement the fine work being done through the Roll Back Malaria Partnership (RBM), which is an initiative of the World Health Organization, UNICEF, and the World Bank. The site is divided into four primary areas, including a publications section and information about events sponsored by the initiative. Visitors unfamiliar with the disease may want to peruse the FAQ section, as it answers some basic queries, such as â??How is it transmitted?â? and â??How can Malaria be controlled?â?. One key document that has recently been released to the site is the Roll Back Malaria Global Strategic Plan, which is available in English and French. Finally, the site also has an audio and video archive which includes a number of public service announcements and video clips that detail some of the RBMâ??s primary activities.

  7. Roll back malaria update.

    Science.gov (United States)

    1999-10-01

    This article presents the activities under WHO's Roll Back Malaria (RBM) program in Asia, particularly in Nepal, Indonesia, India, Bangladesh, Sri Lanka and the Philippines. In India, the RBM program will start in 5 districts with a major malaria problem. A national committee has been formed by researchers, which will be able to provide operational and strategic support and research expertise in relation to malaria. In Bangladesh, the RBM program was initiated in the sparsely populated hill tract areas of Banderban and Chittagong where access to health care is very poor. At the district level, effective partnerships with private practitioners, politicians, community leaders, school teachers, the press and district Ministry of Health officials are operating to plan for rolling back malaria. In Myanmar, Cambodia, Lao People's Democratic Republic, Yunnan province of China, Vietnam, and Thailand, the focus of the RBM program was to move health care closer to the malaria-infected communities. WHO¿s Global Health Leadership Fellowship Programme, supported by the UN Foundation and Rockefeller Foundation, enables potential leaders to experience the work of UN agencies and contribute to the work of the organization for 2 years. Three out of four persons appointed to the RBM program received prestigious awards: Dr. Paola Marchesini of Brazil; Dr. Tieman Diarra of Mali; and Dr. Bob Taylor of the UK. PMID:12295474

  8. Numerical simulation of CICC rolling process

    International Nuclear Information System (INIS)

    The rolling process of cable in conduit conductor (CICC) has been simulated using the explicit dynamic finite element analysis software ANSYS/LS-DYNA. The rolling forces for different rolling passes and the influence of the rolling pass on conductor shape and conductor remainder stress have been obtained. The simulated rolling force matches the reference experimental data, and therefore the study results provide an important basis for the design of rolling equipment. (authors)

  9. Rolling friction of adhesive microspheres

    International Nuclear Information System (INIS)

    The rolling friction of adhesive microspheres is an important quantity as it determines the strength and stability of larger aggregates. Current models predict rolling forces that are 1 to 2 orders of magnitude smaller than observed experimentally. Starting from the well-known Johnson–Kendall–Roberts (JKR) contact description, we derive an analytical theory for the rolling friction based on the concept of adhesion hysteresis, e.g. a difference in apparent surface energies for opening/closing cracks. We show how adhesion hysteresis causes the pressure distribution within the contact to become asymmetrical, leading to an opposing torque. Analytical expressions are derived relating the size of the hysteresis, the rolling torque, and the rolling displacement, ?. We confirm the existence of a critical rolling displacement for the onset of rolling, the size of which is set by the amount of adhesion hysteresis and the size of the contact area. We demonstrate how the developed theory is able to explain the large rolling forces and particle-size dependence observed experimentally. Good agreement with experimental results is achieved for adhesion hysteresis values of (??/?) ? 3 for polystyrene, and (??/?) ? 0.5 for silicates, at crack propagation rates of 0.1 µm s?1 and 1–10 µm s?1, respectively. (paper)

  10. Advances and patents about grinding equipments with nano-particle jet minimum quantity lubrication.

    Science.gov (United States)

    Jia, Dongzhou; Li, Changhe; Wang, Sheng; Zhang, Qiang; Hou, Yali

    2014-01-01

    In recent years, a large number of patents have been devoted to developing minimum quantity lubrication (MQL) grinding techniques that can significantly improve both environmentally conscious and energy saving and costeffective sustainable grinding fluid alternatives. Among them, one patent is about a controllable nano-fluids jet MQL grinding system based on electrostatic atomization. Using the principle of electrostatics, it can achieve the control of droplet transfer by charging the sprayed droplets. This system can improve the uniformity of the droplet spectrum, liquid deposition efficiency and effective utilization of liquid. It can also effectively control the movement patterns of the droplets, thereby reducing the pollution of the environment and providing better health protection for workers. Although researchers accomplished profound and systematic studies on MQL, especially on nano-particles jet MQL. It can solve the shortage of MQL in cooling performance, greatly improve the working environment, save energy and reduce costs to achieve a low-carbon manufacturing. The unique lubricating performance and tribological property of solid nano-particles form nano-particle shearing films at the grinding wheel/workpiece interface, which can enhance the lubricating performance of MQL grinding. Existing studies on MQL grinding equipments, however, cannot meet the needs of the technological development. Therefore, our research provided a general introduction of the latest patients and research progress of nanoparticles jet MQL grinding equipments presented by the research team from Qingdao Technological University. PMID:25336175

  11. Modelling of fracture wear in vitrified cBN grinding wheels

    Directory of Open Access Journals (Sweden)

    M.J. Jackson

    2007-09-01

    Full Text Available Purpose: The paper describes modelling of fracture wear in vitrified cBN grinding wheels.Design/methodology/approach: The approach used in the paper is based on using finite elements to model fracture wear processes in vitrified cBN grinding wheels. The approach used models fracture wear processes and ignores abrasive wear of the abrasive grains.Findings: The findings show that during grinding the grain is subjected to forces that create fracture initiation zones in the sharp abrasive grains where tensile and compressive stresses dominate in certain parts of the abrasive grains.Research limitations/implications: The findings show that further research is required that prevents the formation of crack initiation zones and considers the effects of wear flats on the magnitude of stresses in the abrasive grains.Practical implications: The results imply that abrasive fracture wear is the dominant wear mechanism when grinding with sharp vitrified cBN grinding wheels.Originality/value: The originality of this paper is reflected in the fact that this is the first time that fracture wear has been modelled in sharp vitrified cBN grinding wheels. The results presented in this paper will illuminate the need for accurate modelling of the wear of vitrified superabrasive grinding wheels.

  12. Grinding efficiency of abutment tooth with both dentin and core composite resin on axial plane.

    Science.gov (United States)

    Miho, Otoaki; Sato, Toru; Matsukubo, Takashi

    2015-01-01

    The purpose of this study was to evaluate grinding efficiency in abutment teeth comprising both dentin and core composite resin in the axial plane. Grinding was performed over 5 runs at two loads (0.5 or 0.25 N) and two feed rates (1 or 2 mm/sec). The grinding surface was observed with a 3-D laser microscope. Tomographic images of the grinding surfaces captured perpendicular to the feed direction were also analyzed. Using a non-ground surface as a reference, areas comprising only dentin, both dentin and core composite resin, or only core composite resin were analyzed to determine the angle of the grinding surface. Composite resins were subjected to the Vickers hardness test and scanning electron microscopy. Data were statistically analyzed using a one-way analysis of variance and multiple comparison tests. Multiple regression analysis was performed for load, feed rate, and Vickers hardness of the build-up material depending on number of runs. When grinding was performed at a constant load and feed rate, a greater grinding angle was observed in areas comprising both dentin and composite resin or only composite resin than in areas consisting of dentin alone. A correlation was found between machinability and load or feed rate in areas comprising both dentin and composite resin or composite resin alone, with a particularly high correlation being observed between machinability and load. These results suggest that great caution should be exercised in a clinical setting when the boundary between the dentin and composite resin is to be ground, as the angle of the grinding surface changes when the rotating diamond point begins grinding the composite resin. PMID:25765571

  13. Normalised spectra in monitoring of rolling bearing elements

    Science.gov (United States)

    Martin, K. F.; Thorpe, P.

    1992-12-01

    This paper deals in detail with the monitoring and fault diagnosis of rolling element bearings by use of the 'envelope' technique. It describes an extension of the technique by 'normalizing' the frequency spectra of the faulty bearing with respect to the healthy bearing. This is shown to give much greater sensitivity to the detection of defect frequencies. Earlier work on a test machine was first used to adequately define the envelope technique. After successful demonstration on that machine, the technology was transferred to the main spindle of a milling machine.

  14. Relationships between gluten content and grinding properties of wheat (a short communication)

    OpenAIRE

    Devaux M.F.; Laskowski J.; Le Deschault de Monredon F.

    1999-01-01

    In 14 wheat samples from mixed varieties, the wet gluten content was significantly correlated with grinding energy and particle size of flours. The particle size distributions were bimodal with a main mode between 570 and 690 mm and a second mode between 28 and 34 mm. The main mode was higher for samples with a high gluten content. Conversely, samples with a low gluten content exhibited a higher second mode. A grinding ability index calculated as the quotient of specific grinding energy to sp...

  15. Effect of Grinding Induced Damage on Bending Strength of RBSiC

    Directory of Open Access Journals (Sweden)

    YAO Wang,ZHANG Yu-Min,HAN Jie-Cai,ZHA Yan-Feng£¬ZHOU Yu-Feng,HAN Yuan-Yuan,QU Wei

    2009-03-01

    Full Text Available The effect of surface residual stress and crack on bending strength of reaction bonded silicon carbide (RBSiC after grinding was investigated. The residual stress of the ground surfaces were determined using X-ray diffraction.The sizes of strength controlling cracks were assessed using fracture mechanics approach. The investigations show that mechanical load, which has relation with grinding direction, phays a dominateve role in the grinding processes. and the measured residual stresses have a direction dependency. With increase of down feed from 0.9¦?/s to 1.35¦?/s, the bending strength is reasonably correlated with the surface residual stress and crack size.

  16. Effects of hardness of abrasive grains on surface roughness of work piece in PVA bonded grinding wheel

    International Nuclear Information System (INIS)

    The purpose of this study is to clarify relation between hardness of abrasive grains and surface roughness of work piece in the case of PVA (Polyvinyl alcohol) bonded grinding wheels. Two PVA bonded grinding wheels; with diamond or silicon carbide as abrasive grains and grinding of glass and aluminum alloy was performed. The PVA bonded grinding wheels The PVA bonded grinding wheel with silicon carbide could not grind the glass. Because insufficiency in hardness, the PVA bonded grinding wheel with the diamond abrasive grains caused deep scratch on the aluminum alloy. It was found that the final surface roughness of the work piece was not proportional to the hardness of abrasive grains. The suitable hardness of abrasive grains will be obtained by the hardness of work piece. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  17. Development of an ``intelligent grinding wheel`` for in-process monitoring of ceramic grinding. Semi-annual report {number_sign}4

    Energy Technology Data Exchange (ETDEWEB)

    Malkin, S.; Gao, R.; Guo, C.; Varghese, B.; Pathare, S.

    1998-09-30

    The overall objective of this project is to develop sensor-integrated ``intelligent`` diamond wheels for grinding of ceramics. Such wheels will be ``smart`` enough to monitor and supervise both the wheel preparation and grinding processes without the need to instrument the machine tool. Intelligent wheels will utilize re-useable cores integrated with sensors: to measure the acoustic emission (AE) and grinding force. Signals from the sensors will be transmitted from a rotating wheel to a receiver by telemetry. Wheels will be ``trained`` to recognize distinct characteristics associated with truing, dressing and grinding. This overall project is divided into six tasks as follows: (1) development of miniaturized sensors and data transmission system; (2) wheel design and sensor configuration; (3) calibration of the sensor integrated wheel; (4) training of the intelligent wheel; (5) grinding tests; and (6) prototype demonstration. The technical progress is summarized in this report according to the tasks. All activity during this period has been concerned with the first two interrelated tasks, which need to be completed before undertaking the remaining tasks.

  18. Determination of the energy and power parameters during groove-rolling

    Directory of Open Access Journals (Sweden)

    S. Mróz

    2007-06-01

    Full Text Available Purpose: In order to correctly design the process of bar rolling in grooves it is required that several limitations affecting the rolling process be considered. When developing a technology, energy and force parameters, among others, are needed to be taken into account. Therefore, it is purposeful to examine variations in the energy and force parameters during the rolling of bars.Design/methodology/approach: Using FEM-based computer programs for solving the problems of the theory of plasticity enables determining the energy and force parameters in complex plastic working processes and also accounting for a number of process specificities, which are not provided for by the empirical formula.Findings: The theoretical values of the rolling torque and power during the rolling of band in the grooves, as determined using the Forge3® software and the engineering method proposed by Chekmarev, were compared with the experimental values obtained from the measurements of current loads in a plant manufacturing bars. The current loads of the main drive of the continuous rolling mill for rolling bars were measured in one of the Polish steelworks.Practical implications: Change in the band temperature over its length influences the variations in the magnitudes of widening and advance. Its variations lead to a change in energy–force parameters.Originality/value: Using the FE programs for the computation of the values of the energy–force parameters can take into account the distribution of temperature over the band length.

  19. Rolling Stone Radio

    Science.gov (United States)

    Rolling Stone Radio is a fun and interesting site that may represent the future of Internet radio. The site provides a number of streaming audio channels that can be listened to via RealNetworks' RealPlayer G2 combined with a customized, radio-like interface to the site. Each channel features a particular genre of music, and the interface displays the artist and song title during play. The sound quality ranges from acceptable to excellent, and the sound controls and channel selectors are easy-to-use. While the site borders on the exploitative in its advertising and ability to purchase music by clicking through the interface, it does combine some of the best ideas on the Internet into a seamless entertainment package. All downloadable components of this site are free but run only on Win95/98/NT.

  20. Diseño y Evaluación Energética de dos Circuitos de Molienda y Clasificación para un Clinker de Cemento a Escala Piloto / Design and Energy Evaluation of two Grinding and Classifier Circuits of a Pilot Scale Cement Clinker

    Scientific Electronic Library Online (English)

    Adriana M, Osorio; Juan M, Marín; Gloria, Restrepo.

    Full Text Available Se presentan los resultados del diseño y evaluación de dos sistemas de molienda en circuito cerrado, para un clasificador tipo ciclón neumático y uno tipo harnero vibratorio. Se comparan las eficiencias energéticas bajo similares condiciones de granulometrías a la entrada del molino, conservando el [...] mismo tamaño de corte en el clasificador. El material se caracterizó mediante: fluorescencia de rayos X, area superficial por el método Brunauer-Emmet-Teller y análisis granulométrico por tamizado. Los resultados indican que la velocidad de giro del molino no tiene significancia estadística sobre la eficiencia mecánica de molienda. A partir de un análisis de superficies de respuestas se determinó que el ciclón favorece la eficiencia (valor óptimo 30%) comparado con el harnero (valor óptimo 18%). Los modelos encontrados para la determinación de la eficiencia mecánica del sistema molino-ciclón y molino-harnero, muestran correlaciones del 85 y 83 % respectivamente. Abstract in english The design and experimental evaluation of two grinding systems in closed circuit which use two types of classifiers, a pneumatic cyclone and a sieve vibratory, were carried out. The energetic efficiencies under similar conditions in material particle sizes at the mill entrance and keeping the same c [...] lassifier were compared. The material was characterized by: X-ray fluorescence (XRF), surface area by the method Brunauer-Emmet-Teller and granulometry analysis by sieving. Results show that the mill speed does not have statistical significance over the grinding mechanical efficiency and using a response surface analysis was determined that the cyclone favors the milling (optimum value 30%) against the sieve vibratory type (optimum 18%). Models found for mechanical efficiency determination of the systems mill-cyclone and mill-sieve vibratory, show correlations of 85 % and 83%, respectively.

  1. Synthesis of vanadium-modified rutile TiO2 nanoparticle by reactive grinding method and its photocatalytic activity under solar light at room temperature

    Science.gov (United States)

    Nguyet Tran, Thi Minh; Hoang Yen Quach, Thi; Tran, Que Chi; Nguyen, Thi Toan; Chien Nguyen, Van; Do, Hung Manh; Thanh Tran, Dang; Nhung Nguyen, Hong; Tuyen Vu, Phi; Khuong Le, Dang

    2013-09-01

    Rutile TiO2 was synthesized by sol–gel method. Vanadium-doped rutile TiO2 nanoparticle was obtained by reactive grinding method. The photocatalytic activity was evaluated by the degradation of methylene blue (MB) under solar light at room temperature. The results show that after 4 h of milling the particle size of rutile decreased from 130 to 14 nm and the Brunauer–Emmet–Teller (BET) specific surface area increased from 7.18 to 15.12 m2 g?1. The vanadium doping promoted the particle growth and the particle size of vanadium-modified rutile TiO2 obtained by 4 h of milling is about 22 nm, but the BET specific surface area increased from 15.12 m2 g?1 for TiO2 to 20.8 m2 g?1 for vanadium-doped TiO2 under the same conditions. The 5% vanadium-doped rutile possessed better absorption ability of solar light; the calculated band gap energy value is 2.7 eV. The degradation rate of MB on vanadium-doped rutile TiO2 was higher than that of pure rutile obtained after the same time of milling.

  2. Synthesis of vanadium-modified rutile TiO2 nanoparticle by reactive grinding method and its photocatalytic activity under solar light at room temperature

    International Nuclear Information System (INIS)

    Rutile TiO2 was synthesized by sol–gel method. Vanadium-doped rutile TiO2 nanoparticle was obtained by reactive grinding method. The photocatalytic activity was evaluated by the degradation of methylene blue (MB) under solar light at room temperature. The results show that after 4 h of milling the particle size of rutile decreased from 130 to 14 nm and the Brunauer–Emmet–Teller (BET) specific surface area increased from 7.18 to 15.12 m2 g?1. The vanadium doping promoted the particle growth and the particle size of vanadium-modified rutile TiO2 obtained by 4 h of milling is about 22 nm, but the BET specific surface area increased from 15.12 m2 g?1 for TiO2 to 20.8 m2 g?1 for vanadium-doped TiO2 under the same conditions. The 5% vanadium-doped rutile possessed better absorption ability of solar light; the calculated band gap energy value is 2.7 eV. The degradation rate of MB on vanadium-doped rutile TiO2 was higher than that of pure rutile obtained after the same time of milling. (paper)

  3. THE STUDY OF SCALE FORMATION ON HOT ROLLED INGOTS AND BILLETS

    Directory of Open Access Journals (Sweden)

    GHEORGHE VLAICU

    2010-06-01

    Full Text Available During the heating for rolling, ingots and billets are affected by the chemical action of the heating atmosphere. Between the heating environment elements and steel components there are taking place chemical reactions initiated at the separation surface that may affect a layer in metal of about a few microns to a few millimeters. The thickness of the affected layer is a function of the environment nature, heated material composition, chemical reaction’s type and kinetics, heating rate and temperature. The aim of this paper is to correlate the oxidation and the decarburization processes during the heating of ingots and billets for rolling. The study was made on ingots and billets rolled at the breakdown mill of the Special Steel Complex, Physics Laboratories from MECHEL Targoviste, Romania. The scope of the study is the analysis of the scale obtained from the rolling mill train in order to obtain specific information that will be used in adjusting the rolling parameters for diminishing the oxidation and decarburization and for recycling the scale in electric furnaces.

  4. Failure Analysis of Rollers in mill stand using Failure mode Effect Analysis

    Directory of Open Access Journals (Sweden)

    Tadisetti Premsai

    2014-07-01

    Full Text Available Rolling is an important steel production process. Productivity and quality improvements in metal rolling are possible by paying a detailed attention to the various roll failure modes.A proper understanding of the causes of roll failure modes is usually complex and depends on the metallurgical quality of rolls, improper mill usage practices and abnormal rolling conditions. The work rolls operate under severe condition and should posses excellent wear resistance and very little plastic deformation to withstand mechanical and thermal shocks. The objective of this study is to analyze different failures associated with rollers in the mill stand using Failure Mode Effect Analysis (FMEA. The values of severity, probability of occurrence and detection of each failure mode are taken according to the FMEA criteria and based on these values, Risk Priority Number of each failure mode is calculated. Based on the risk levels of each failure modes, remedies for the respective failure modes are presented. Thus it results in reduced risk of process failure, improved reliability and quality of the products.

  5. Grinding of AISI 4340 steel with interrupted cutting by aluminum oxide grinding wheel / Retificação do aço AISI 4340 usando corte interrompido com rebolo convencional

    Scientific Electronic Library Online (English)

    Hamilton Jose de, Mello; Diego Rafael de, Mello; Eduardo Carlos, Bianchi; Paulo Roberto de, Aguiar; Doriana M., D' Addona.

    2015-06-01

    Full Text Available Resumo No processo de retificação, muito já se avançou com o desenvolvimento de métodos de dressagem de rebolos, de lubrirefrigeração e de outros mais. Todavia, todos esses progressos foram conseguidos apenas no que diz respeito ao corte contínuo, ou seja, o perfil da peça retificada não sofre desco [...] ntinuidade alguma. Nesse sentido, torna-se necessário o estudo do processo de retificação por corte intermitente (peça com ranhuras – corte descontínuo), pois pouco ou, mesmo, nenhum conhecimento e/ou estudo foi desenvolvido com esse enfoque, visto que não é encontrado material algum na literatura formal, salvo aqueles em que o rebolo é o detentor das ranhuras. Na retificação, o calor gerado na zona de corte é extremamente elevado. Dessa forma, o uso de fluidos de corte é indispensável para que seja possível refrigerar, tanto a peça, quanto o rebolo e propiciar melhorias na operação de corte, sendo o mais comum a utilização de fluido em abundância, tendo em vista que os agentes de arrefecimento e lubrificação são capazes de proporcionar uma retificação mais eficiente. Os ensaios foram realizados com um rebolo convencional de óxido de alúmínio, retificando corpos-de-prova confeccionados com aço ABNT 4340 temperado e revenido com 2, 6 e 12 ranhuras. A operação cilíndrica utilizada foi de mergulho, ou seja, o rebolo avança sobre a peça em movimento de rotação. Esse avanço é realizado com três velocidades distintas. Dos resultados obtidos, pode-se observar que a rugosidade tendeu a aumentar, para CP's com mesmo número de ranhuras, conforme foi aumentada a velocidade de mergulho. Os erros de circularidade, assim como a rugosidade, também tenderam a aumentar com o aumento da velocidade de mergulho, para CP's com mesmo número de ranhuras. O desgaste do rebolo tendeu a aumentar conforme aumentados a velocidade de mergulho e o número de ranhuras. A potência consumida pela retificadora foi inversamente proporcional ao número de ranhuras. A microdureza subsuperficial não provocou alteração significativa. E as micrografias revelaram que a usinagem foi satisfatória, pois não houve danos significativos à superficie usinada. Abstract in english Abstract There has been a great advance in the grinding process by the development of dressing, lubri-refrigeration and other methods. Nevertheless, all of these advances were gained only for continuous cutting; in other words, the ground workpiece profile remains unchanged. Hence, it becomes necess [...] ary to study grinding process using intermittent cutting (grooved workpiece – discontinuous cutting), as little or no knowledge and studies have been developed for this purpose, since there is nothing found in formal literature, except for grooved grinding wheels. During the grinding process, heat generated in the cutting zone is extremely high. Therefore, plenty of cutting fluids are essential to cool not only the workpiece but also the grinding wheel, improving the grinding process. In this paper, grinding trials were performed using a conventional aluminum oxide grinding wheel, testing samples made of AISI 4340 steel quenched and tempered with 2, 6, and 12 grooves. The cylindrical plunge grinding was performed by rotating the workpiece on the grinding wheel. This plunge movement was made at three different speeds. From the obtained results, it can be observed that roughness tended to increase for testing sample with the same number of grooves, as rotation speed increased. Roundness error also tended to increase as the speed rotation process got higher for testing the sample with the same number of grooves. Grinding wheel wear enhanced as rotation speed and number of grooves increased. Power consumed by the grinding machine was inversely proportional to the number of grooves. Subsuperficial microhardness had no significant change. Micrographs reveal an optimal machining operation as there was no significant damage on the machined surface.

  6. 75 FR 62566 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia

    Science.gov (United States)

    2010-10-12

    ...Review)] Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia AGENCY: United...duty order on hot-rolled flat-rolled carbon-quality steel products (``hot-rolled steel'') from Brazil,...

  7. 75 FR 42782 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia

    Science.gov (United States)

    2010-07-22

    ...Review)] Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia AGENCY: United...on certain hot-rolled flat-rolled carbon-quality steel products (``hot-rolled steel'') from Brazil,...

  8. Rolling tool calibration for cold rolling of tubes

    International Nuclear Information System (INIS)

    An analysis was made of calibration methods for step-back rolling of tubes from austenitic steels to meet the order of nuclear power for tubes with a high quality of inner surfaces. On the basis of this analysis the optimization criterion chosen was the observance of the constant value of the ratio of wall thickness deformation to the deformation of tube diameter for any length of a tube. A logarithmic function was derived for the shape of the rolling pin. Operating trials showed that rolling instruments of the given design have a favourable effect on the quality of the inner surface of tubes and on the even load of the rolling system in an operating cycle. (Ha)

  9. Roll Control in Fruit Flies

    CERN Document Server

    Beatus, Tsevi; Cohen, Itai

    2014-01-01

    Due to aerodynamic instabilities, stabilizing flapping flight requires ever-present fast corrective actions. Here we investigate how flies control body roll angle, their most susceptible degree of freedom. We glue a magnet to each fly, apply a short magnetic pulse that rolls it in mid-air, and film the corrective maneuver. Flies correct perturbations of up to $100^{\\circ}$ within $30\\pm7\\mathrm{ms}$ by applying a stroke-amplitude asymmetry that is well described by a linear PI controller. The response latency is $\\sim5\\mathrm{ms}$, making the roll correction reflex one of the fastest in the animal kingdom.

  10. Numerical simulation of shape rolling

    OpenAIRE

    Riljak, Stanislav

    2006-01-01

    In the first part of this thesis, the FE program MSC.Marc is applied for coupled thermomechanical simulations of wire-rod rolling. In order to predict material behaviour of an AISI 302 stainless steel at high strain rates generated during wire-rod rolling, a material model based on dislocation density is applied. Then, the evolution of temperature, strain rate and flow stress is predicted in the first four rolling passes of a wire block. In the second part of the thesis, an alternative approa...

  11. Design and fundamental understanding of Minimum Quantity Lubrication (MQL) assisted grinding using advanced nanolubricants

    Science.gov (United States)

    Kalita, Parash

    Abrasive grinding is widely used across manufacturing industry for finishing parts and components requiring smooth superficial textures and precise dimensional tolerances and accuracy. Unlike any other machining operations, the complex thermo-mechanical processes during grinding produce excessive friction-induced energy consumption, heat, and intense contact seizures. Lubrication and cooling from grinding fluids is crucial in minimizing the deleterious effects of friction and heat to maximize the output part quality and process efficiency. The conventional flood grinding approach of an uneconomical application of large quantities of chemically active fluids has been found ineffective to provide sufficient lubrication and produces waste streams and pollutants that are hazardous to human health and environment. Application of Minimum Quantity Lubrication (MQL) that cuts the volumetric fluid consumption by 3-4 orders of magnitude have been extensively researched in grinding as a high-productivity and environmentally-sustainable alternative to the conventional flood method. However, the lubrication performance and productivity of MQL technique with current fluids has been critically challenged by the extreme thermo-mechanical conditions of abrasive grinding. In this research, an MQL system based on advanced nanolubricants has been proposed to address the current thermo-mechanical challenges of MQL grinding and improve its productivity. The nanolubricants were composed of inorganic Molybdenum Disulphide nanoparticles (? 200 nm) intercalated with organic macromolecules of EP/AW property, dispersed in straight (base) oils---mineral-based paraffin and vegetable-based soybean oil. After feasibility investigations into the grindability of cast iron using MQL with nanolubricants, this research focused on the fundamental understanding of tribological behavior and lubricating mechanisms of nanolubricants as a method to improve the productivity of MQL-assisted surface grinding of ductile iron and alloy steel. An extensive investigation on MQL-assisted grinding using vitrified aluminum oxide wheel under varied infeed and lubrication condition was carried out with the scope of documenting the process efficiency and lubrication mechanisms of the nanolubricants. Experimental results showed that MQL grinding with nanolubricants minimized the non-productive outputs of the grinding process by reducing frictional losses at the abrasive grain-workpiece interfaces, energy consumption, wheel wear, grinding zone temperatures, and friction-induced heat generation. Use of nanolubricants in MQL yielded superior productivity by producing surface roughness as low as 0.35 ?m and grinding efficiencies that were four times higher as compared to those obtained from flood grinding. Repeatable formation of tribochemical films of antifriction, antiwear, and extreme pressure chemical species in between the contact asperities of abrasive crystals and work material was identified with nanolubricants. The tribological behavior was characterized by this synergistic effect of the antiwear, antifriction, and load carrying chemical species that endured grain-workpiece seizures and reduced adhesion friction between the contact surfaces. Delivery of organic coated Molybdenum Disulphide nanoparticles by anchoring on the natural porosity of the abrasive wheel and eventually, sliding-induced interfacial deformation into tribolayers and alignment at the grinding zone were established as the lubrication mechanisms of the nanolubricants. These mechanisms were further validated from tribological evaluations of lubricated cubic boron nitride (cBN) superabrasives-1045 steel sliding pairs on a reciprocating tribotest rig resembling the tool-lubricant-workpiece interactions of MQL-assisted grinding.

  12. Optimization of Cylindrical Grinding Process Parameters on C40E Steel Using Taguchi Technique

    Directory of Open Access Journals (Sweden)

    Naresh Kumar

    2015-01-01

    Full Text Available Surface finish and dimensional accuracy play a vital role in the today’s engineering industry. There are several methods used to achieve good surface finish like burnishing, honing and lapping, and grinding. Grinding is one of these ways that improves the surface finish and dimensional accuracy simultaneously. C40E steel has good industrial application in manufacturing of shafts, axles, spindles, studs, etc. In the present work the cylindrical grinding of C40E steel is done for the optimization of grinding process parameters. During this experimental work input process parameters i.e. speed, feed, depth of cut is optimized using Taguchi L9 orthogonal array. Analysis of variance (ANOVA concluded that surface roughness is minimum at the 210 rpm, 0.11mm/rev feed, and 0.04mm depth of penetration.

  13. Mechanochemical reactions studied by in situ Raman spectroscopy: base catalysis in liquid-assisted grinding.

    Science.gov (United States)

    Tireli, Martina; Juribaši? Kulcsár, Marina; Cindro, Nikola; Gracin, Davor; Biliškov, Nikola; Borovina, Mladen; ?uri?, Manda; Halasz, Ivan; Užarevi?, Krunoslav

    2015-05-11

    In situ Raman spectroscopy was employed to study the course of a mechanochemical nucleophilic substitution on a carbonyl group. We describe evidence of base catalysis, akin to catalysis in solution, achieved by liquid-assisted grinding. PMID:25866133

  14. Effects of mechanical grinding and low temperature annealing on crystal structure of Er5Si4

    International Nuclear Information System (INIS)

    Highlights: ? Impurity phases exist in orthorhombic Er5Si4:monoclinic 5:4, 1:1 and 5:3. ? Mechanical grinding induces transition from orthorhombic 5:4 to monoclinic 5:4. ? Low temperature annealing reverses the monoclinic 5:4 to orthorhombic 5:4. -- Abstract: The effect of mechanical grinding and subsequent low temperature annealing on the orthorhombic to monoclinic structural transition in the Er5Si4 compound was studied by X-ray powder diffraction using both a conventional laboratory Cu K?1 radiation and a high-energy synchrotron source. A reversible phase transition from the orthorhombic to monoclinic structure occurs as a result of mechanical grinding. Low temperature annealing reverses the transformation and converts the formed monoclinic phase back to the orthorhombic, evidently by relieving residual stress introduced during the grinding

  15. Effect of electroerosion grinding parameters on surface quality of cylindrical pieces out of tungsten monocrystals

    International Nuclear Information System (INIS)

    Experimental data are presented on the examination of the electroerosion grinding of cylindrical parts made up of tungsten single crystals. Special attention has been paid to a comparative analysis of the influence of the electroerosion cutting out and grinding on the quality characteristics of a surface. The surface quality was assessed according to a widening of the X-ray emission line (110) by means of round diffraction patterns and by the metallographic method. It is shown that the microdistortions after the electroerosion grinding are considerably greater than those resulting from the electroerosion cutting out; however, after the electroerosion grinding the number of microcracks is considerably smaller. The experimental results obtained underwent a theoretical analysis within the framework of the Mitchell-Rockswell-Hirsch dislocation theory of failure of space-centered single crystals

  16. Robots grind rotor blades for wind power systems; Roboter schleifen Rotorblaetter fuer Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Drenkelfort, Gunnar [GDC Consulting GmbH, Guetersloh (Germany)

    2009-11-30

    An integrated concept for automatic manufacturing of wind power systems is presented for the first time. Automatic grinding of rotor blades by robots is a key element, which saves up to 70 percent of the production cost. (orig.)

  17. Preparation and characterization of nanocrystalline ZrO2-7%Y2O3 powders for thermal barrier coatings by high-energy ball milling

    Science.gov (United States)

    Bobzin, Kirsten; Zhao, Lidong; Schlaefer, Thomas; Warda, Thomas

    2011-06-01

    High-energy ball milling is an effective method to produce nanocrystalline oxides. In this study, a conventional ZrO2-7%Y2O3 spray powder was ball-milled to produce nanocrystalline powders with high levels of crystalline disorders for deposition of thermal barrier coatings. The powder was milled both with 100Cr6 steel balls and with ZrO2-3%Y2O3 ceramic balls as grinding media. The milling time was varied in order to investigate the effect of the milling time on the crystallite size. The powders were investigated in terms of their crystallite sizes and morphologies by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that under given milling conditions the powder was already nanostructured after 40 min milling. The crystallite size decreased significantly with increasing milling time within first 120 min. After that, a further increase of milling time did not lead to a significant reduction of the crystallite size. Ball-milling led to lattice microstrains. Milling with the steel balls resulted in finer nano-sized crystal grains, but caused the contamination of the powder. The nano-sized crystal grains coarsened during the heat-treatment at 1250°C.

  18. Austenitic steel rolling in the temperature range of anomalous ductility

    International Nuclear Information System (INIS)

    Investigations are carried out on the strips of the Kh14G14N3T (EhI-711), OOOKh18N12 and Kh16N16M3B (EhI-847) steels, deformed, by shot rolling with summary reductions up to 80 % under conditions close to isothermal, at the temperatures in the range of 196-400 deg C as well as on the working cones of tube rolling of the 12Kh18N10T steel using the tube-cold-rolling mill at 20, 100, 200 and 300 deg C, their heating in the deformation focus has not been hindered. Dislocation structure and phase composition of the steels have been investigated using the methods of optical and electron microscopy, X-ray (in iron Ksub(?)-irradiation) and electron diffraction. It is shown that the effect of anomalous ductility during austenitic steel rolling is manifested in the temperature range being the lower the more stable austenit is in them and reaches the maximum at higher temperature than at stretching. The nature of anomalous ductility effect is complex and the essence of it is not only in stress relaxation in the process of phase transformations. Formation of stacking faults and transverse slipping, producing effect upon dislocation structure formation of austenite during rollling, plays a very importand role. Manifestation of the anomalous ductility effect depends on deformation heating an6 produces considerable effect upon formation of technological defects (cracks, fissures and so on) upon the treatment purity of the rolled surface of sheet and tubesheet and tubes

  19. Optimal Cluster Mill Pass Scheduling With an Accurate and Rapid New Strip Crown Model

    Science.gov (United States)

    Malik, Arif S.; Grandhi, Ramana V.; Zipf, Mark E.

    2007-05-01

    Besides the requirement to roll coiled sheet at high levels of productivity, the optimal pass scheduling of cluster-type reversing cold mills presents the added challenge of assigning mill parameters that facilitate the best possible strip flatness. The pressures of intense global competition, and the requirements for increasingly thinner, higher quality specialty sheet products that are more difficult to roll, continue to force metal producers to commission innovative flatness-control technologies. This means that during the on-line computerized set-up of rolling mills, the mathematical model should not only determine the minimum total number of passes and maximum rolling speed, it should simultaneously optimize the pass-schedule so that desired flatness is assured, either by manual or automated means. In many cases today, however, on-line prediction of strip crown and corresponding flatness for the complex cluster-type rolling mills is typically addressed either by trial and error, by approximate deflection models for equivalent vertical roll-stacks, or by non-physical pattern recognition style models. The abundance of the aforementioned methods is largely due to the complexity of cluster-type mill configurations and the lack of deflection models with sufficient accuracy and speed for on-line use. Without adequate assignment of the pass-schedule set-up parameters, it may be difficult or impossible to achieve the required strip flatness. In this paper, we demonstrate optimization of cluster mill pass-schedules using a new accurate and rapid strip crown model. This pass-schedule optimization includes computations of the predicted strip thickness profile to validate mathematical constraints. In contrast to many of the existing methods for on-line prediction of strip crown and flatness on cluster mills, the demonstrated method requires minimal prior tuning and no extensive training with collected mill data. To rapidly and accurately solve the multi-contact problem and predict the strip crown, a new customized semi-analytical modeling technique that couples the Finite Element Method (FEM) with classical solid mechanics was developed to model the deflection of the rolls and strip while under load. The technique employed offers several important advantages over traditional methods to calculate strip crown, including continuity of elastic foundations, non-iterative solution when using predetermined foundation moduli, continuous third-order displacement fields, simple stress-field determination, and a comparatively faster solution time.

  20. Optimal Cluster Mill Pass Scheduling With an Accurate and Rapid New Strip Crown Model

    International Nuclear Information System (INIS)

    Besides the requirement to roll coiled sheet at high levels of productivity, the optimal pass scheduling of cluster-type reversing cold mills presents the added challenge of assigning mill parameters that facilitate the best possible strip flatness. The pressures of intense global competition, and the requirements for increasingly thinner, higher quality specialty sheet products that are more difficult to roll, continue to force metal producers to commission innovative flatness-control technologies. This means that during the on-line computerized set-up of rolling mills, the mathematical model should not only determine the minimum total number of passes and maximum rolling speed, it should simultaneously optimize the pass-schedule so that desired flatness is assured, either by manual or automated means. In many cases today, however, on-line prediction of strip crown and corresponding flatness for the complex cluster-type rolling mills is typically addressed either by trial and error, by approximate deflection models for equivalent vertical roll-stacks, or by non-physical pattern recognition style models. The abundance of the aforementioned methods is largely due to the complexity of cluster-type mill configurations and the lack of deflection models with sufficient accuracy and speed for on-line use. Without adequate assignment of the pass-schedule set-up parameters, it may be difficult or impossible to achieve the required strip flatness. In this paper, we demonstrateip flatness. In this paper, we demonstrate optimization of cluster mill pass-schedules using a new accurate and rapid strip crown model. This pass-schedule optimization includes computations of the predicted strip thickness profile to validate mathematical constraints. In contrast to many of the existing methods for on-line prediction of strip crown and flatness on cluster mills, the demonstrated method requires minimal prior tuning and no extensive training with collected mill data. To rapidly and accurately solve the multi-contact problem and predict the strip crown, a new customized semi-analytical modeling technique that couples the Finite Element Method (FEM) with classical solid mechanics was developed to model the deflection of the rolls and strip while under load. The technique employed offers several important advantages over traditional methods to calculate strip crown, including continuity of elastic foundations, non-iterative solution when using predetermined foundation moduli, continuous third-order displacement fields, simple stress-field determination, and a comparatively faster solution time

  1. Thermodynamic and kinetic characterization of polymorphic transformation of famotidine during grinding.

    Science.gov (United States)

    Lin, Shan-Yang; Cheng, Wen-Ting; Wang, Shun-Li

    2006-08-01

    Two polymorphs of famotidine were prepared by recrystallization from acetonitrile for form A and methanol for form B, respectively. The effect of grinding process on the polymorphic transformation of famotidine was investigated. Each famotidine sample ground for various grinding times in a ceramic mortar was determined by differential scanning calorimetry (DSC), conventional and thermal Fourier transform infrared (FT-IR) microspectroscopy. The results indicate that the raw material of famotidine was proved to be a form B. A unique IR absorption band at 3505 cm(-1) for famotidine form B gradually decreased its intensity with the grinding time, while two newer IR absorption bands at 3451 and 1671 cm(-1) for famotidine form A slowly appeared. The peak intensity ratio of 3451/350 5 cm(-1) was linearly (r=0.9901) increased with the grinding time, suggesting that the grinding process could induce the polymorphic transformation of famotidine from form B to form A by a zero-order process. The DSC endothermic peaks also confirmed this polymorphic transformation from famotidine form B (167 degrees C, DeltaH: 165J/g) to famotidine form A (174 degrees C, DeltaH: 148J/g) in which the values of enthalpy were linearly reduced with the increase of grinding time (r=0.9943). The phase transition temperature of the different ground famotidine samples could be easily and only evidenced by using thermal FT-IR microspectroscopy, rather than by DSC analysis. These phase transition temperatures of the famotidine form B ground for 5-20 min quickly reduced from 144 to 134 degrees C and maintained a constant at 134 degrees C even after 20-30 min grinding. The grinding process not only decreased the crystallinity of famotidine form B but also reduced the particle size of famotidine form B, resulting in easy induction of the polymorphic transformation of famotidine from form B to form A in ground famotidine sample. PMID:16647827

  2. Co-processing of Grinding Sludge as Alternative Raw Material in Portland Cement Clinker Production

    Directory of Open Access Journals (Sweden)

    M. Wecharatana

    2010-01-01

    Full Text Available This research aimed to investigate the potential of partial substitution of cement raw meal with grinding sludge as an alternative raw material in Portland cement clinker production. Cement raw mixtures with up to 3% raw mix replacement were put through a burning process in a high-temperature furnace. One reference and three modified mixtures, containing 1, 2 and 3% dry weight of grinding sludge were examined. XRF analysis results showed that CaO, SiO2, Al2O3 and Fe2O3 in ordinary cement raw meal were within typical concentration ranges. The grinding sludge had high concentrations of iron, cadmium, chromium and nickel and was consequently classified as a hazardous waste. High Fe2O3 made the grinding sludge a good candidate for alternative raw material. Higher replacement of grinding sludge was found to improve burnability, reduce formation of major of cement compositions (dicalcium silicate, C2S and tricalcium aluminate, C3A, lower in silica and alumina ratios, but promote the formation of tricalcium silicate (C3S and tetracalcium aluminateferrite (C4AF. Microstructural analysis of the synthesized Portland clinker revealed that the grinding sludge promoted formation of secondary C2S as well as caused color change of C3S. Thai regulatory leaching procedure was performed on the synthesized clinker and mortar samples. The concentrations of heavy metals in the leachate were found below the limits. Moreover, the maximum substitution of grinding sludge was found to be 2% of grinding sludge. Thus, this sludge has potential applications as an alternative raw material in cement production.

  3. Next generation grinding spindle for cost-effective manufacture of advanced ceramic components

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, J.A.; Laurich, M.A.

    2000-01-01

    Finish grinding of advanced structural ceramics has generally been considered an extremely slow and costly process. Recently, however, results from the High-Speed, Low-Damage (HSLD) program have clearly demonstrated that numerous finish-process performance benefits can be realized by grinding silicon nitride at high wheel speeds. A new, single-step, roughing-process capable of producing high-quality silicon nitride parts at high material removal rates while dramatically reducing finishing costs has been developed.

  4. New Abrasive Materials and Their Influence on the Surface Quality of Bearing Steel After Grinding

    OpenAIRE

    Ondrej Jusko

    2012-01-01

    This paper focuses on the influence of various types of abrasive grains on cutting properties during the grinding process for bearing steel. In this experiment, not only conventional super-hard abrasive materials but also a new type of abrasive material were employed in grinding wheels. The measurement results were compared, and an evaluation was made of the cutting properties of the new abrasive material. The options were then evaluated for their practical applicability. The measurement resu...

  5. Influence of chemistry and hot rolling conditions on high permeability non-grain oriented silicon steel

    International Nuclear Information System (INIS)

    This paper discusses the influence of chemical composition on the final electromagnetic properties in higher permeability material. Furthermore, the effect of the hot rolling practice and the end of austenite transformation temperature range on the hot band microstructure is described. The magnetic polarization J 5000 better than 1.7 T, using hot rolling conditions 40 mm transfer bar thickness, finish mill entry temperature 1000 deg. C, and finishing temperature 800-840 deg. C and after decarburization heat treatment and grain growth treatment, was obtained

  6. Rolling Resistance Measurement and Model Development

    DEFF Research Database (Denmark)

    Andersen, Lasse Grinderslev; Larsen, Jesper

    2015-01-01

    There is an increased focus worldwide on understanding and modeling rolling resistance because reducing the rolling resistance by just a few percent will lead to substantial energy savings. This paper reviews the state of the art of rolling resistance research, focusing on measuring techniques, surface and texture modeling, contact models, tire models, and macro-modeling of rolling resistance

  7. Rolling Process Modeling Report: Finite-Element Prediction of Roll Separating Force and Rolling Defects

    Energy Technology Data Exchange (ETDEWEB)

    Soulami, Ayoub; Lavender, Curt A.; Paxton, Dean M.; Burkes, Douglas

    2014-04-23

    Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum (U-10Mo) alloy plate-type fuel for the U.S. high-performance research reactors. This work supports the Convert Program of the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA) Global Threat Reduction Initiative. This report documents modeling results of PNNL’s efforts to perform finite-element simulations to predict roll separating forces and rolling defects. Simulations were performed using a finite-element model developed using the commercial code LS-Dyna. Simulations of the hot rolling of U-10Mo coupons encapsulated in low-carbon steel have been conducted following two different schedules. Model predictions of the roll-separation force and roll-pack thicknesses at different stages of the rolling process were compared with experimental measurements. This report discusses various attributes of the rolled coupons revealed by the model (e.g., dog-boning and thickness non-uniformity).

  8. Improving Energy Efficiency Via Optimized Charge Motion and Slurry Flow in Plant Scale Sag Mills

    Energy Technology Data Exchange (ETDEWEB)

    Raj K. Rajamani

    2006-07-21

    A research team from the University of Utah is working to make inroads into saving energy in these SAG mills. In 2003, Industries of the Future Program of the Department of Energy tasked the University of Utah team to build a partnership between the University and the mining industry for the specific purpose of reducing energy consumption in SAG mills. A partnership was formed with Cortez Gold Mines, Outokumpu Technology, Kennecott Utah Copper Corporation, and Process Engineering Resources Inc. At Cortez Gold Operations the shell and pulp lifters of the semiautogenous grinding mill was redesigned. The redesigned shell lifter has been in operation for over three years and the redesigned pulp lifter has been in operation for over nine months now. This report summarizes the dramatic reductions in energy consumption. Even though the energy reductions are very large, it is safe to say that a 20% minimum reduction would be achieved in any future installations of this technology.

  9. High speed low damage grinding of advanced ceramics - Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, J.A.; Malkin, S.

    2000-02-01

    In the manufacture of structural ceramic components, grinding costs can comprise up to 80% of the entire manufacturing cost. As a result, one of the most challenging tasks faced by manufacturing process engineers is the development of a ceramic finishing process to maximize part throughput while minimizing costs and associated scrap levels. The efforts summarized in this report represent the second phase of a program whose overall objective was to develop a single-step, roughing-finishing process suitable for producing high-quality silicon nitride parts at high material removal rates and at substantially lower cost than traditional, multi-stage grinding processes. More specifically, this report provides a technical overview of High-Speed, Low-Damage (HSLD) ceramic grinding which employs elevated wheel speeds to achieve the small grain depths of cut necessary for low-damage grinding while operating at relatively high material removal rates. The study employed the combined use of laboratory grinding tests, mathematical grinding models, and characterization of the resultant surface condition. A single-step, roughing-finishing process operating at high removal rates was developed and demonstrated.

  10. Modeling and optimization of cylindrical grinding of Al/SiC composites using genetic algorithms

    Directory of Open Access Journals (Sweden)

    C. Thiagarajan

    2012-03-01

    Full Text Available The Al/SiC composites have received more commercial attention than other kinds of Metal Matrix Composites (MMCs due to their high performance. However, a continuing problem with MMCs is that they are difficult to machine, due to the hardness and abrasive nature of the SiC particles. Grinding is often the method of choice for machining Al/SiC composites to acquire high dimensional accuracy and surface finish in large scale production. Based on the full factorial design (3(4, a total of 81 experiments, each having a combination of different levels of variables, are carried out to study the effect of grinding parameters such as wheel velocity, work piece velocity, feed and depth of cut on the responses such as tangential grinding force, roughness and grinding temperature. Modeling and optimization place a vital role in controlling any process for improved product quality, high productivity and low cost. In the present work, experimental results are used to calculate the analysis of variance (ANOVA which explains the significance of the parameters on the responses. Based on the results of ANOVA, a mathematical model is formulated using multiple regression method. A genetic algorithm (GA based optimization procedure has been developed to optimize the grinding parameters for maximum material removal by imposing constraints on roughness. This methodology would be useful for identifying the optimum grinding parameters in order to achieve the required material removal rate (MRR.

  11. Improved grinding quality inspection of large bearing components using Barkhausen noise analysis

    Science.gov (United States)

    Kolarits, Francis M.

    2014-02-01

    Assuring that the finished surfaces of precision large bearing components are free from grinding injury is important due to the high initial value of these bearings, heavy application loadings and high costs associated with potential reduced service life. Inspecting bearing raceway surfaces for grind burn can be done by nital etching but this method is time consuming, involves using hazardous acids, is non-quantitative and does not provide information about residual stresses. An experimental study was performed to assess scanning Barkhausen Noise Analysis (BNA) to detect various levels of induced grind injury on four steels used in large bearing ring production. Test samples having approximately 0.25 m diameter were fabricated from bearing steels heat treated by case carburizing, induction hardening and through hardening. A series of grinding cycles was designed and subsequently the entire ground surface on each sample was tested by scanning BNA. Selected samples were then evaluated by nital etching or destructive metallurgical tests. BNA results are compared with specific grinding power, nital etch and destructive measurements to show BNA to be an effective technique for identification of grind injury on these steel materials. Similar relative trends in the BNA response are present regardless of alloy or heat treatment.

  12. Modeling and optimization of cylindrical grinding of Al/SiC composites using genetic algorithms

    Scientific Electronic Library Online (English)

    C., Thiagarajan; R., Sivaramakrishnan; S., Somasundaram.

    2012-03-01

    Full Text Available The Al/SiC composites have received more commercial attention than other kinds of Metal Matrix Composites (MMCs) due to their high performance. However, a continuing problem with MMCs is that they are difficult to machine, due to the hardness and abrasive nature of the SiC particles. Grinding is oft [...] en the method of choice for machining Al/SiC composites to acquire high dimensional accuracy and surface finish in large scale production. Based on the full factorial design (3(4)), a total of 81 experiments, each having a combination of different levels of variables, are carried out to study the effect of grinding parameters such as wheel velocity, work piece velocity, feed and depth of cut on the responses such as tangential grinding force, roughness and grinding temperature. Modeling and optimization place a vital role in controlling any process for improved product quality, high productivity and low cost. In the present work, experimental results are used to calculate the analysis of variance (ANOVA) which explains the significance of the parameters on the responses. Based on the results of ANOVA, a mathematical model is formulated using multiple regression method. A genetic algorithm (GA) based optimization procedure has been developed to optimize the grinding parameters for maximum material removal by imposing constraints on roughness. This methodology would be useful for identifying the optimum grinding parameters in order to achieve the required material removal rate (MRR).

  13. Influence of quartz particles on wear in vertical roller mills. : Part I: Quartz concentration

    DEFF Research Database (Denmark)

    Jensen, Lucas R.D.; Friis, Henrik

    2010-01-01

    The standard closed circuit comminution process commonly employed in industrial vertical roller mills has been analyzed to determine the influence of typical abrasive minerals on wear rates. With the main focus on raw mixes used in cement plants, synthetic mixtures imitating were prepared. Using statistical planning, a total of 10 tests were arried out with two different limestones and one type of quartz sand. The size distributions were kept constant and only the mixing ratios were varied. It appears from the investigation that mixtures consisting of minerals with different grindabilities result in an increased concentration of abrasive particles in the grinding bed ðR2 > 0:99Þ. The present study shows that the quartz concentration in the grinding bed is determining the wear rate.

  14. FM Interviews: Stephanie Mills

    OpenAIRE

    Valauskas, Edward

    2002-01-01

    Stephanie Mills is an author, editor, lecturer and ecological activist who has concerned herself with the fate of the earth and humanity since 1969, when her commencement address at Mills College in Oakland, Calif., drew the attention of a nation. Her speech, which the New York Times called "perhaps the most anguished statement" of the year's crop of valedictory speeches, predicted a bleak future. According to Mills, humanity was destined for suicide, the result of overpopulation and overuse ...

  15. Numerical analysis of cross shear plate rolling

    DEFF Research Database (Denmark)

    Zhang, Wenqi; Bay, Niels

    1997-01-01

    The rolling process is widely applied for industrial production of metal plates. In conventional plate rolling the two work rolls are rotating at the same peripheral speed. By introducing a specific difference in the speed of the two work rolls, cross shear rolling is introduced forming a central shear zone between the forward and backward slip zones in the deformation zone thus lowering the rolling load. A numerical analysis of the cross shear rolling process is carried out based on the slab method adopting Wanheim and Bay's general friction model. The pressure distribution along the contact are in the roll gap, the position and the size of the shear zone and the rolling load are calculated. Experimental results are presented verifying the calculations. The numerical analysis facilitates a better understanding of the mechanics in cross shear plate rolling.

  16. Pyrolysis of a waste from the grinding of scrap tyres

    International Nuclear Information System (INIS)

    Highlights: ? The pyrolysis of reinforcing fibres obtained from scrap tyres has been studied. ? The results have been compared to scrap tyre granules. ? A higher temperature is needed for the total decomposition of the fibres. ? More compounds with heteroatoms (O, N) were found in the oil from the fibres. ? Chars from the fibres exhibit lower BET surface and mesopore volume. - Abstract: The fibres that are used to reinforce tyres can be recovered as a waste in the process of grinding of scrap tyres. In this paper beneficiation through pyrolysis is studied since the fibres are made up of polymers with a small amount of rubber because the latter is difficult to separate. The experiments were performed at three temperatures (400, 550 and 900 °C) in a horizontal oven. The three products – gas, oil and char – obtained from the pyrolysis were investigated. The composition of the gas was analyzed by means of gas chromatography. The oil was studied by gas chromatography and infrared spectroscopy. The char porous structure was determined by N2 adsorption. In addition, the topography of the chars was studied by means of scanning electron microscopy (SEM). The products resulting from the pyrolysis of the fibres were compared with those obtained from scrap rubber.

  17. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  18. Constraining fast-roll inflation

    CERN Document Server

    Noller, Johannes

    2012-01-01

    We present constraints on how far single field inflation may depart from the familiar slow-roll paradigm. Considering a fast-roll regime while requiring a near-scale invariant power spectrum introduces large self-interactions for the field and consequently large and scale-dependent non-Gaussianities. Employing this signal, we use the requirement of weak-coupling together with WMAP constraints to derive bounds on generic $P(X,\\phi)$ theories of single field inflation.

  19. Fundamentals of Rolling Contact Fatigue:

    OpenAIRE

    Grabulov, A.

    2010-01-01

    In the mechanical industry there is a need for continuous development towards increasing performance of various types of machinery. Critical components in such machines are exposed to gradually harsher operating environments involving higher cyclic stresses and operating temperatures. Examples of such fatigue-exposed components are gears, camshafts and rolling element bearings in engines and gearboxes. The components in the bearing industry are always subject to the high cycle rolling contact...

  20. Preparation of glibenclamide nanocrystals by a simple laboratory scale ultra cryo-milling

    International Nuclear Information System (INIS)

    The objective of this study is to evaluate the ability to reduce the particle size of glibenclamide (GBC) to the nanometric scale through a very simple and well-known laboratory scale method, the laboratory scale ultra cryo-milling. The effect of milling on GBC crystalline properties and dissolution behaviour was deliberately evaluated in the absence of any surfactants as stabilizers. The milling procedure consisted in adding particles to liquid nitrogen and milling them by hand in a mortar with a pestle for different time intervals (15, 30, 40 min). For comparison, the same milling procedure was also applied without liquid nitrogen. The particle size reduction was evaluated for the coarsest samples (>3 ?m) by measuring the particle Ferret’s diameter through scanning electron microscopy, while for the smallest one (<3 ?m) by dynamic light scattering. A time grinding of 40 min in the presence of liquid nitrogen was revealed highly efficacious to obtain particles of nanodimensions, with a geometric mean particle size of 0.55 ± 0.23 ?m and more than the 80 % of particles lower than 1,000 nm. Interestingly, non-agglomerated particles were obtained. Differential scanning calorimetry and X-ray powder diffractometry allowed to assess that under mechanical treatment no polymorphic transitions were observed, while a decrease in crystallinity degree occurred depending on the milling procedure (presence or absence of liquid nitrogen) and the milling time (crystallinity dec the milling time (crystallinity decreases at increasing milling time from 15 to 40 min). A comparison of the intrinsic dissolution rate and the dissolution from particles revealed an interesting improvement of particle dissolution particularly for particles milled in the presence of liquid nitrogen due to an increase in particle surface area and concentration gradient, according to the Noyes–Whitney equation.

  1. Study of the Influence of Cutting Regime Parameters on Grinding Forces in Processing Tungsten Carbide Dk460uf

    Science.gov (United States)

    Vulc, Silvia

    2014-12-01

    This paper presents a study on grinding tungsten carbide DK460UF, through experimental investigation using diamond grinding wheel with 54 ?m grain size. Different sets of experiments were performed to study the effects of the independent grinding parameters such as grinding wheel speed, feed and depth of cut on cutting forces. Test results showed that the feed and depth of cut influence significantly the cutting forces. The research was lead to optimize the process parameters for reducing cutting forces. In this way, for different parameters of cutting regime, it were measured the values of the components of the grinding force, tangential component, Ft and normal component Fn. The results of the experiment showed that it is better to use great speeds and small feed rate and depth of cut in grinding tungsten carbides, such as DK460UF

  2. Using CCT Diagrams to Optimize the Composition of an As-Rolled Dual-Phase Steel

    Science.gov (United States)

    Coldren, A. Phillip; Eldis, George T.

    1980-03-01

    A continuous-cooling transformation (CCT) diagram study was conducted for the purpose of optimizing the composition of a Mn-Si-Cr-Mo as-rolled dual-phase (ARDP) steel. The individual effects of chromium, molybdenum, and silicon on the allowable cooling rates were determined. On the basis of the CCT diagram study and other available information, an optimum composition was selected. Data from recent mill trials at three steel companies, involving steels with compositions in or near the newly recommended range, are presented and compared with earlier mill trial data. The comparison shows that the optimized composition is highly effective in making the steel's properties more uniform and reproducible in the as-rolled condition.

  3. John Stuart Mill Links

    Science.gov (United States)

    Considered one of the most important philosophers of the 19th century, John Stuart Mill was born in 1806 to one James Mill, part-time philosopher and economist, and full-time official in the East India Company. Educated by both his father and the philosopher Jeremy Bentham, Mill learned Greek by age three, Latin shortly thereafter, and was a competent logician by age 12. After suffering a mental breakdown at the age of 20, Mill decided he would commit himself to persuading the general public of the need for a scientific and rational approach to understanding social, political, and economic change. Mill penned some of the most powerful statements on the behalf of utilitarianism during his life, including one of his most enduring works, Utilitarianism. This Web site (offered in numerous different languages) is a compilation of links to works by and about Mill, including full-text versions of such works as On Liberty, Principles of Political Economy, and his Autobiography. Equally compelling are the works about Mill also to be found here, most notably Isaiah Berlin's 1959 article, John Stuart Mill and the Ends of Life.

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

    Science.gov (United States)

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

    2015-03-01

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

  5. Material and process issues in electrolytic in-process dressing (ELID)-grinding

    Science.gov (United States)

    Chen, Hong

    This research covers research and development of the electrolytic in-process dressing (ELID) grinding technology, where material and process issues are systematically investigated. Experiments on anodic oxidation of cast iron and bronze were performed to determine the growth behavior of the oxides on the metals, their structures and mechanical properties. With SEM and optical microscope, a special technique to measure the oxide thickness was also developed. A series of theoretical calculations was carried out to highlight the fact that the localized dissolution of the metals around diamond particle results in exposing the cutting edge for efficient grinding and/or cutting. A model was proposed on the basis of experimental observations and theoretical calculations. It was the first quantitative model that explores the ELID mechanism and could serve guidance to optimize ELID-grinding operations for many applications. This model recognized the key feature of the oxide layer in the process, formulated the dynamic balance between its growth and wear, and emphasized the important role of its nonlinear growth. It not only brought a link between performance and process parameters, but also explained the experimental results and helped ELID-grinding practice. Grinding experiments performed on OPTICAM PM showed that with a proper selection of operation parameters from the proposed model, (1) ELID-grinding improved surface roughness (RMS) a factor of five for Zerodur; (2) Ductile grinding modes were achieved for Zerodur, BK-7 and SF-6; (3) Mirror finish (RMS saw with ELID and computer controlled data acquisition, capable of measuring the cutting depth, force and ELID current/voltage. Experiments on cutting various materials with or without ELID showed that ELID could improve cutting effectively.

  6. Statistical Modeling of Pin Gauge Dimensions of Root of Gas Turbine Blade in Creep Feed Grinding Process

    OpenAIRE

    Ahmad Reza Fazeli

    2010-01-01

    Creep feed grinding is a recently invented process of material handling. It combines high quality of the piece surface, productivity, and the possibility of automatic control. The main objectives of this research is to study the influences of major process parameters and their interactions of creep feed grinding process such as wheel speed, workpiece speed, grinding depth, and dresser speed on the pin gauge dimensions of root of gas turbine blade by design of experiments (DOE). Experimental r...

  7. The project and technical study on the track of vertical axis linkage abrasive belt grinding of turbine blade

    International Nuclear Information System (INIS)

    A method of CNC turbine blade profile abrasive belt grinding is introduced based on optimum grinding effect, where the direction of the axis of trolley wheel is consistent with that of minimum principal curvature on the contact point of turbine blade. And the cutter location path is determined, and then the NC code is derived from post-processing. A virtual machine model is built in VERICUT software to simulate actual grinding process and applied in practice, which yielded satisfactory results. (authors)

  8. A new model-based approach for power plant Tube-ball mill condition monitoring and fault detection

    International Nuclear Information System (INIS)

    Highlights: • This is the first mathematical model of power plant Tube-ball mills to cover the whole milling process. • A novel on-line model based power plant condition monitoring method is reported. • The online implementation of the model is achieved and the model was verified through online test. • The model parameters can be on-line updated/optimised using Genetic Algorithms. - Abstract: With the fast growth in intermittent renewable power generation, unprecedented demands for power plant operation flexibility have posed new challenges to the ageing conventional power plants in the UK. Adding biomass to coal for co-fired power generation has become widely implemented practices in order to meet the emission regulation targets. These have impacted the coal mill and power plant operation safety and reliability. The Vertical Spindle mill model was developed through the authors’ work before 2007. From then, the new research progress has been made in modelling and condition monitoring for Tube-ball mills and is reported in the paper. A mathematical model for Tube-ball milling process is developed by applying engineering principles combined with model unknown parameter identifications using a computational intelligent algorithm. The model describes the whole milling process from the mill idle status, start-up to normal grinding and shut-down. The model is verified using on-site measurement data and on-line test. The on-line model is used for mill condition monitoring in two ways: (i) to compare the predicted and measured mill output pressure and temperatures and to raise alarms if there are big discrepancies; and (ii) to monitor the mill model parameter variation patterns which detect the potential faults and mill malfunctions

  9. Influence of the charge properties on the milling tools wear during intensive milling in liquid environment

    OpenAIRE

    Števulová Nadežda; Aacute Lintov Aacute Magdal Eacute Na, B.

    2002-01-01

    Grinding belongs to the basic technological operations in the treatment and processing of minerals. The method of the intensive grinding in a liquid environment has become attractive for the preparation of technologically advanced materials of the high fineness. Its choice was motivated by the intensification of dispersion and by the protection of ground powder against oxidation. The result of energy and material interactions among the grinding media and grinding environment is the wear of th...

  10. Application of a good manufacturing practices checklist and enumeration of total coliform in swine feed mills

    Directory of Open Access Journals (Sweden)

    Debora da Cruz Payao Pellegrini

    2014-02-01

    Full Text Available A cross-sectional study in four swine feed mills aimed to evaluate the correlation between the score of the inspection checklist defined in the Normative Instruction 4 (IN 4/ Brazilian Ministry of Agriculture, Livestock and Food Supply, and the enumeration of total coliforms throughout the manufacturing process. The most of non-conformities was found in the physical structure of the feed mills. Feed mill B showed the lowest number of unconformities while units A and D had the largest number of nonconformities. In 38.53% (489/1269 of the samples the presence of total coliform was detected, however no significant difference in the bacterial counts was observed between sampling sites and feed mills. The logistic regression pointed higher odds ratio (OR for total coliforms isolation at dosing (OR = 9.51, 95% CI: 4.43 to 20.41, grinding (OR = 7.10, 95% CI = 3.27 to 15.40 and residues (OR = 6.21, 95% CI: 3.88 to 9.95 In spite of having the second score in the checklist inspection, feed mill C presented the highest odds for total coliforms isolation (OR= 2,43, IC 95%: 1,68-3,53. The data indicate no association between the score of checklist and the presence of hygienic indicators in feed mills.

  11. Optimal control of conditions of deformation during rolling the bar alloy from alloy steel

    International Nuclear Information System (INIS)

    A complex of programs for determining the optimal gaps between rollers during rolling of simple merchant sections of alloy steels of a wide brand assortment (12KhN3A, Kh17N2, Kh18N10T) was elaborated. Experience in calculations made according to the programs suggests advisability of their use in the automated design systems for roller calibration and for adjustment of section mills

  12. Roll-to-roll manufacturing of electronic devices

    Science.gov (United States)

    Morrison, N. A.; Stolley, T.; Hermanns, U.; Kroemer, U.; Reus, A.; Lopp, A.; Campo, M.; Landgraf, H.

    2012-03-01

    Roll-to-Roll (R2R) production of thin film based electronic devices (e.g. solar cells, activematrix TFT backplanes & touch screens) combine the advantages of the use of inexpensive, lightweight & flexible substrates with high throughput production. Significant cost reduction opportunities can also be found in terms of processing tool capital cost, utilized substrate area and process gas flow when compared with batch processing systems. Nevertheless, material handling, device patterning and yield issues have limited widespread utilization of R2R manufacturing within the electronics industry.

  13. Preparation of glibenclamide nanocrystals by a simple laboratory scale ultra cryo-milling

    Energy Technology Data Exchange (ETDEWEB)

    Martena, Valentina; Censi, Roberta [University of Camerino, School of Pharmacy (Italy); Hoti, Ela; Malaj, Ledjan [University of Tirana, Department of Pharmacy (Albania); Martino, Piera Di, E-mail: piera.dimartino@unicam.it [University of Camerino, School of Pharmacy (Italy)

    2013-06-15

    The objective of this study is to evaluate the ability to reduce the particle size of glibenclamide (GBC) to the nanometric scale through a very simple and well-known laboratory scale method, the laboratory scale ultra cryo-milling. The effect of milling on GBC crystalline properties and dissolution behaviour was deliberately evaluated in the absence of any surfactants as stabilizers. The milling procedure consisted in adding particles to liquid nitrogen and milling them by hand in a mortar with a pestle for different time intervals (15, 30, 40 min). For comparison, the same milling procedure was also applied without liquid nitrogen. The particle size reduction was evaluated for the coarsest samples (>3 {mu}m) by measuring the particle Ferret's diameter through scanning electron microscopy, while for the smallest one (<3 {mu}m) by dynamic light scattering. A time grinding of 40 min in the presence of liquid nitrogen was revealed highly efficacious to obtain particles of nanodimensions, with a geometric mean particle size of 0.55 {+-} 0.23 {mu}m and more than the 80 % of particles lower than 1,000 nm. Interestingly, non-agglomerated particles were obtained. Differential scanning calorimetry and X-ray powder diffractometry allowed to assess that under mechanical treatment no polymorphic transitions were observed, while a decrease in crystallinity degree occurred depending on the milling procedure (presence or absence of liquid nitrogen) and the milling time (crystallinity decreases at increasing milling time from 15 to 40 min). A comparison of the intrinsic dissolution rate and the dissolution from particles revealed an interesting improvement of particle dissolution particularly for particles milled in the presence of liquid nitrogen due to an increase in particle surface area and concentration gradient, according to the Noyes-Whitney equation.

  14. Development of a Shape Difficulty Factor in Shape Rolling by LS-DYNA Modeling

    Science.gov (United States)

    Lenard, John G.; Svyetlichnyy, Dmitry; Biglou, Jalal

    2004-06-01

    Calculation of power requirements is an important part of the design of new or reconstructed rolling mills. Empirical methods that estimate the power requirements have been developed in the past. The modern methods, based on the finite element method, allow for the direct, accurate and consistent modeling of the shape rolling process. However, the wide range of the variations of the parameters of the process and the long time taken by 3D FEM calculations make the modeling difficult. The manuscript presents results obtained during the modeling of shape rolling by LS-DYNA. A novel method, to determine the power via a shape difficulty coefficient, calculated through geometrical parameters of the initial metal shape and the shape of the grooves, is then presented. A comparison of the predictions of the new method with that of other techniques of calculations is also given.

  15. The use of cylindrical grinding to produce a martensitic structure on the surface of 4340 Steel

    Scientific Electronic Library Online (English)

    André de, Lima; Luiz Sérgio, Gâmbaro; Milton, Vieira Junior; Elesandro Antonio, Baptista.

    2011-03-01

    Full Text Available Grinding is one of the most widely used manufacturing processes and, in the last few decades, has developed considerably. An example of these developments is hardening by grinding, an operation that is being studied to provide an option to the conventional hardening processes. This study presents th [...] e use of a cylindrical grinding process to produce a martensitic structure on the surface of SAE 4340 steel workpieces, and aims at adjusting the parameters of this process. To do much, a set of experiments were carried out using three cycles of grinding: the first one just to obtain a workpiece with regular diameter; the second cycle is that which will provide heating and cooling of the ground workpiece; and the last cycle is to provide corrections to the dimensions and roughness. Results of the experiments showed that hardening by grinding is possible and that the workpiece achieved hardness levels compatible to those provided by the conventional hardening processes. The use of such a process for surface hardening purposes has been researched and developed with a view to increasing the productivity of the process, ensuring dimensional and surface quality, in addition to mechanical resistance.

  16. Westinghouse Modular Grinding Process - Enhancement of Volume Reduction for Hot Resin Supercompaction - 13491

    International Nuclear Information System (INIS)

    In nuclear power plants (NPP) ion exchange (IX) resins are used in several systems for water treatment. Spent resins can contain a significant amount of contaminates which makes treatment for disposal of spent resins mandatory. Several treatment processes are available such as direct immobilization with technologies like cementation, bitumisation, polymer solidification or usage of a high integrity container (HIC). These technologies usually come with a significant increase in final waste volume. The Hot Resin Supercompaction (HRSC) is a thermal treatment process which reduces the resin waste volume significantly. For a mixture of powdered and bead resins the HRSC process has demonstrated a volume reduction of up to 75 % [1]. For bead resins only the HRSC process is challenging because the bead resins compaction properties are unfavorable. The bead resin material does not form a solid block after compaction and shows a high spring back effect. The volume reduction of bead resins is not as good as for the mixture described in [1]. The compaction properties of bead resin waste can be significantly improved by grinding the beads to powder. The grinding also eliminates the need for a powder additive.Westinghouse has developed a modular grinding process to grind the bead resin to powder. The developed process requires no circulation of resins and enables a selective adjustment of particle size and distribution to achieve optimal results in the HRSC or in any other following process. A special grinding tool setup is use to minimize maintenance and radiation exposure to personnel. (authors)

  17. Comparing different plunge cylindrical grinding cycles based on workpiece roughness and process vibration

    Scientific Electronic Library Online (English)

    Wanderley Xavier, Pereira; Anselmo Eduardo, Diniz; Amauri, Hassui.

    2009-06-01

    Full Text Available Grinding is an important process used when tight dimensional accuracy and low workpiece surface roughness are demanded. Despite the fact that grinding is widely used in industry, it is not well understood. The elastic deformation, which occurs in the beginning of the cycles, makes it necessary a spa [...] rk out in the end of the cycle. An alternative to this is the use of a three-phase cycle. The main objective of this work is to compare the plunge cylindrical conventional grinding cycle (with spark out) and a three-phase one in terms of workpiece surface roughness. In order to accomplish this goal, several plunge grinding of hardened AISI 4340 steel experiments were carried out using both kinds of cycles in different grinding conditions. The vibration signal of the system was acquired in order to better understand the differences between the two kinds of cycles. The main conclusion was that conventional cycle produces lower workpiece surface roughness than the three-phase one (both with the same cycle time). It happens because the elastic deformation is better released in the conventional cycle.

  18. Techniques for chamfer and taper grinding of oxide fuel pellets (LWBR Development Program)

    International Nuclear Information System (INIS)

    Floor mounted centerless grinding machines were adapted for shaping the edges of cylindrical oxide fuel pellets for the Light Water Breeder Reactor (LWBR) by plunge grinding. Edge configurations consisted of chamfers, either 0.015 inch x 450 or 0.006 inch x 450, or tapers 0.150 inch long x .0025 inch deep. Grinding was done by plunging the pellet against a shaped grinding wheel which ground both the diameter to the required size and shaped the edges of the pellet. Two plunges per pellet were required to complete the operation. Separate wheels were needed for grinding either a chamfer or a taper, the set up was adjustable to vary the size of the chamfer or taper as needed. The set up also had the flexibility to accommodate the multiple pellet lengths and diameters required by the LWBR design. Tight manufacturing tolerances in the chamfer and taper dimensions required the use of dimensional control charts and statistical sampling plans as process controls

  19. On an Interpretation of Mill’s Qualitative Utilitarianism

    Directory of Open Access Journals (Sweden)

    CHRISTOPH SCHMIDT-PETRI

    2006-12-01

    Full Text Available This paper is a reply to Jonathan Riley’s criticism of my reading of Mill(both published in the Philosophical Quarterly 2003. I show that Riley’s interpretation has no textual support in Mill’s writing by putting the supposedly supporting quotations in their proper context. Secondly it is demonstrated how my reading is not incompatible with hedonism. Mill’s use of the concepts of ‘quality’, ‘quantity’, and ‘pleasure’ are explained and illustrated. I conclude by considering whether the possible redundancy of Mill’s quality/quantity discussion would be problematic.

  20. Robust Rudder Roll Damping Control

    DEFF Research Database (Denmark)

    Yang, C.

    1998-01-01

    The results of a systematic research to solve a specific ship motion control problem, simultaneous roll damping and course keeping using the rudder are presented in this thesis. The fundamental knowledge a priori is that rudder roll damping is highly sensitive to the model uncertainty, therefore H-infinity theory is used to deal with the problem. The necessary mathematical tools and the H-Infinity theory as the basis of controller design are presented in Chapter 2 and 3. The mu synthesis and the D-K iteration are introduced in Chapter 3. The ship dynamics and modeling technology are discussed in Chapter 4, two kinds of ship model have been obtained: linear ship model used for designing the controller and nonlinear model used for simulation. The ship model uncertainty is discussed in this chapter and so is a wave model because the ship's roll motion is caused by waves. Using an unstructured model of uncertainty, three controllers with different kind of control schemes are designed by the mixed sensitivity method in Chapter 5. Sea-way simulation results show that each of these controllers have good robust stability and performance. The roll damping reduction is above 35% for all of these controllers. Roll reduction of near 70% has been obtained by the cascade controller. Using structured model of uncertainty, a m controller is designed in Chapter 6. The good robust performance has been recognized in the simulation results. It is shown that the m controller has the best robust characteristics with respect to model uncertainty and the roll reduction is near 50% with an envelope of model perturbations.

  1. Effect of surface shear on cube texture formation in heavy cold-rolled Cu-45 at%Ni alloy substrates

    DEFF Research Database (Denmark)

    Tian, Hui; Suo, Hongli

    2015-01-01

    Two types of Cu-45 at%Ni alloy thin tapes with and without surface shear were obtained by different heavy cold rolling processes. The deformation and recrystallization textures of the two tapes were thoroughly investigated by electron back scattering diffraction technique. The results showed that a shear texture mainly covered the surface of the heavy deformed tapes because of the fraction between the surface of rolling mills and the thin tapes when the rolling force strongly reduced at high strain, which significantly reduced the fraction of rolling texture on the surface of the Cu-45at %Ni alloy thin tapes, retarded the cube grain growth during recrystallization and affected the strong cube texture formation after high temperature annealing.

  2. Research on the characterization and conditioning of uranium mill tailings. II. Thermal stabilization of uranium mill tailings: technical and economic evaluation. Volume 2

    International Nuclear Information System (INIS)

    A method of conditioning uranium mill tailings has been devised to greatly reduce radon emanation and contaminant leachability by using high-temperature treatments, i.e., thermal stabilization. The thermally stabilized products appear resistant to weathering as measured by the effects of grinding and water leaching. The technical feasibility of the process has been partially verified in pilot-scale experiments. A conceptual thermal stabilization process has been designed and the economics of the process show that the thermal stabilization of tailings can be cost competitive compared with relocation of tailings during remedial action. The alteration of morphology, structure, and composition during thermal treatment would indicate that this stabilization method may be a long-lasting solution to uranium mill tailings disposal problems

  3. Tuning the length dispersion of multi-walled carbon nanotubes by ball milling

    Directory of Open Access Journals (Sweden)

    László Forró

    2013-09-01

    Full Text Available The statistical analysis of the length distribution of catalytic chemical vapour deposition synthesized multi-walled carbon nanotubes cut by planetary ball milling is reported. The nanotube lengths follow a log-normal distribution in a broad range of grinding time and rotational speed. We show that the scale parameter of the distribution, which equals the mean of the natural logarithm of the tube lengths, decreases linearly with the product of the duration time and the rotational speed. This relation can be used for tailoring nanotube lengths by a suitable choice of process parameters for a wide range of applications.

  4. Cell sorting by deterministic cell rolling†‡

    Science.gov (United States)

    Choi, Sungyoung; Karp, Jeffrey M.; Karnik, Rohit

    2012-01-01

    This communication presents the concept of “deterministic cell rolling”, which leverages transient cell-surface molecular interactions that mediate cell rolling to sort cells with high purity and efficiency in a single step. PMID:22327803

  5. Cell sorting by deterministic cell rolling

    OpenAIRE

    Choi, Sungyoung; Karp, Jeffrey M.; Karnik, Rohit

    2011-01-01

    This communication presents the concept of “deterministic cell rolling”, which leverages transient cell-surface molecular interactions that mediate cell rolling to sort cells with high purity and efficiency in a single step.

  6. Electronic BAR Gauge: a customized optical rail profile measurement system for rail-grinding applications

    Science.gov (United States)

    Bachinsky, Gordon S.

    1995-06-01

    The dynamic interaction that occurs at the rail/wheel interface of any rail system is significantly influenced by rail and wheel profiles. In an effort to enhance this interaction, railways and transit systems often employ rail grinding as a means to maintain a defined rail profile. The cost to perform this procedure can be very high, sometimes exceeding $DLR25,000 per day for the use of a large grinding machine (with up to 128 grinding motors-each motor being 20 hp or more). Because of this, it is imperative that the work be done efficiently and accurately. In recent years there has been substantial research into the optimization of rail profiles. The National Research Council (NRC) of Canada is one research facility that has generated a unique, precise set of specified profiles for use in heavy-haul railway operations. To implement these profiles in a consistent manner, during rail grinding operations, requires some type of measurement system that provides feedback to the field staff. Up until recently, this has been accomplished with a manual BAR gauge that is fitted with a set of accurate profile templates. The BAR gauge, which initially was fitted with four specified templates, is now equipped with ten such templates. To obtain the full potential of benefits from these profiles requires more precise grinding than that which has been achieved in the past. The other problem with the current manual profile measurement (BAR) method is that it is somewhat slow and cumbersome and the differences between profiles is quite small (i.e. 0.020 inch or less). In order to enhance their rail grinding management support, ARM pursued an automated system that would optically measure rail profiles very fast and accurately from a hy-rail vehicle and compare them with the NRC profiles. Another important feature that was desired in this system was the ability to measure the relative position of one profile with respect to the other (i.e. left versus right rail). Such a system would thus be able to look at both rail profiles in one x-y plane, which is what the manual BAR gauge provides, to produce an electronic simulation of the desired templates oriented with each other in the proper manner, and compares this with the actual profiles. In order to compare actual profiles with the NRC profiles, it is necessary that both rails be looked at simultaneously in one x-y plane. This is mandatory if you want to duplicate the capabilities of the manual BAR gauge. Other parameters such as cant angle, head loss, track gauge, and section rail weight are also calculated at the same time. After evaluating various technologies, ARM selected the Electronic BAR Gauge, manufactured by Range Vision Inc. of Canada. The Electronic BAR Gauge is a second generation piece of equipment that enables you to measure rail profiles and wear within a resolution of 0.001 inch. It is utilized ahead of the grinding program to create a pre-grind survey plan and during grinding operations as a quality control device to verify desired profile installation and to monitor metal removal rates. The Electronic BAR Gauge will help ARM move towards the next generation of rail grinding strategy; namely being able to grind in a true preventive manner, whereby the work is carried out in a predictive manner with just the right amount of metal being removed from the rail in just the right places. This is referred to as the 'magic wear rate'. This paper presents the features of the Electron BAR Gauge, concentrating on how the system has been specifically designed to meet the needs of ARM for their rail grinding applications. Another section describes the accuracy requirements of the system and provides insight on the technology utilized.

  7. Microwave-assisted grinding of metallurgical coke; Molienda asistida con microondas de un coque metalurgico

    Energy Technology Data Exchange (ETDEWEB)

    Ruisanchez, E.; Juarez-Perez, E. J.; Arenillas, A.; Bermudez, J. M.; Menendez, J. A.

    2014-10-01

    Metallurgical cokes are composed of graphitic carbon (s2p2) and different inorganic compounds with very different capacities to absorb microwave radiation. Moreover, due to the electric conductivity shown by the metallurgical cokes, microwave radiation produces electric arcs or microplasmas, which gives rise to hot spots. Therefore, when these cokes are irradiated with microwaves some parts of the particle experiment a rapid heating, while some others do not heat at all. As a result of the different expansion and stress caused by thermal the shock, small cracks and micro-fissures are produced in the particle. The weakening of the coke particles, and therefore an improvement of its grind ability, is produced. This paper studies the microwave-assisted grinding of metallurgical coke and evaluates the grinding improvement and energy saving. (Author)

  8. The influence of microstructure on the mechanical properties of metallurgical rolls made of G200CrMoNi4-3-3 cast steel

    OpenAIRE

    A. Brodziak; Z. Stradomski; A. Pirek

    2009-01-01

    The subject of the study is the high-carbon tool cast steel G200CrMoNi4-3-3 used for metallurgical rolls, especially in section rolling mills. The test material was derived from a roll damaged in production; therefore, the authors had the material in a raw state at their disposal, on which they were able to carry out additional heat treatment operations. The pearlitic matrix of casting steel G200CrMoNi4-3-3 allows machining to be done to modify the pass or to remove any defects, and the prima...

  9. Ambient roll-to-roll fabrication of flexible solar cells based on small molecules

    DEFF Research Database (Denmark)

    Lin, Yuze; Dam, Henrik Friis

    2013-01-01

    All solution-processed roll-to-roll flexible solar cells based on a starshaped small molecule donor and PCBMacceptor were fabricated by slot-die coating, as the first successful example reported for small molecule roll-to-roll flexible solar cells.

  10. Application of the Minimum Quantity Lubrication (MQL) technique in the plunge cylindrical grinding operation

    Scientific Electronic Library Online (English)

    José Augusto Camargo, Alves; Ulysses de Barros, Fernandes; Carlos Elias da, Silva Júnior; Eduardo Carlos, Bianchi; Paulo Roberto de, Aguiar; Eraldo Jannone da, Silva.

    2009-03-01

    Full Text Available Precision cylindrical grinding is used extensively in the manufacture of precision components in the metal-mechanical industry in general. Modern CNC grinding machines have improved this process with respect to the positioning and rigidity of the machine-workpiece-tool system, allowing the productio [...] n of high precision parts with low dimensional tolerances. Besides the difficulties inherent to the process, awareness has grown in recent years regarding the environmental issues of cutting fluids. As a response, the industry has begun to seek alternative lubrication and cooling methods. Among the various existing techniques, Minimum Quantity Lubrication (MQL) has been considered as an alternative. This technique can be understood as a combination of conventional lubrication and cooling methods and dry machining, in which a small quantity of lubricating oil mixed with compressed air flow is delivered in the wheel-workpiece interface. The MQL technique is already widely employed in machining processes with tools of defined geometry (e.g. turning), in which produces very satisfactory results. However, the MQL technique has been little explored in grinding processes (non-defined tool geometry), in which the really effective heat removal methods are required due to the frictional heat generation in the grinding zone. Consequently, the aim of this study was to evaluate the plunge cylindrical internal grinding operation when using the MQL technique and the conventional cooling method. Roughness and roundness were the outputparameters. As a result, it was found that the best values of roughness Ra were obtained with the conventional lubrication method. The MQL technique applied as proposed was not able to flush the chips away from the grinding zone, leading to the highest Ra values. No significant differences were detected among the cooling methods when analyzing the roundness results. The workpiece fixture method selected was responsible for the overall unsatisfactory results.

  11. Application of the Minimum Quantity Lubrication (MQL technique in the plunge cylindrical grinding operation

    Directory of Open Access Journals (Sweden)

    José Augusto Camargo Alves

    2009-03-01

    Full Text Available Precision cylindrical grinding is used extensively in the manufacture of precision components in the metal-mechanical industry in general. Modern CNC grinding machines have improved this process with respect to the positioning and rigidity of the machine-workpiece-tool system, allowing the production of high precision parts with low dimensional tolerances. Besides the difficulties inherent to the process, awareness has grown in recent years regarding the environmental issues of cutting fluids. As a response, the industry has begun to seek alternative lubrication and cooling methods. Among the various existing techniques, Minimum Quantity Lubrication (MQL has been considered as an alternative. This technique can be understood as a combination of conventional lubrication and cooling methods and dry machining, in which a small quantity of lubricating oil mixed with compressed air flow is delivered in the wheel-workpiece interface. The MQL technique is already widely employed in machining processes with tools of defined geometry (e.g. turning, in which produces very satisfactory results. However, the MQL technique has been little explored in grinding processes (non-defined tool geometry, in which the really effective heat removal methods are required due to the frictional heat generation in the grinding zone. Consequently, the aim of this study was to evaluate the plunge cylindrical internal grinding operation when using the MQL technique and the conventional cooling method. Roughness and roundness were the outputparameters. As a result, it was found that the best values of roughness Ra were obtained with the conventional lubrication method. The MQL technique applied as proposed was not able to flush the chips away from the grinding zone, leading to the highest Ra values. No significant differences were detected among the cooling methods when analyzing the roundness results. The workpiece fixture method selected was responsible for the overall unsatisfactory results.

  12. Ion Milling of Sapphire

    Science.gov (United States)

    Gregory, Don A.; Herren, Kenneth A.

    2004-01-01

    The ion milling of sapphire is a complicated operation due to several characteristics of the material itself. It is a relatively hard transparent nonconductive crystalline material that does not transfer heat nearly as well as metals that have been successfully ion milled in the past. This investigation involved designing an experimental arrangement, using existing ion milling equipment, as the precursor to figuring the surface of sapphire and other insulating optical materials. The experimental arrangement employs a laser probe beam to constantly monitor the stresses being induced in the material, as it is being ion milled. The goal is to determine if the technique proposed would indeed indicate the stress being induced in the material so that these stresses can be managed to prevent failure of the optic.

  13. Research on Bamboo Charcoal Bonded Grinding Wheel and Its Mechanical Properties

    Science.gov (United States)

    Li, Wei; Xu, Minjie; Zhan, Fangyong; Jin, Mingsheng

    2014-08-01

    In this paper, a new type of grinding wheel and its manufacturing production process are introduced. The new BCB (Bamboo Charcoal Bond) grinding wheel was made of bamboo charcoal, phenolic resin and abrasive powder with higher press and temperature. To investigate its mechanical features, such as Rockwell hardness, resistance to abrasion, and resistance to pressure, some experiments on three BCB samples with different Resin weight ratios 20%, 25%, 30%, were carried out. The results showed that the BCB sample with proper moulding process and Resin weight ratio had better performance.

  14. Application and Analysis of Force Control Strategies to Deburring and Grinding

    Directory of Open Access Journals (Sweden)

    Frank Domroes

    2013-06-01

    Full Text Available This paper aims to give an insight into the development and evaluation of force controlled machining processes with a commercially available setup. We will focus on a deburring and a grinding scenario, representing the major applications in today’s robot machining. Whereas the deburring use-case implements a force dependent feed-rate control, the grinding use-case implements an orthogonal force (pressure control. Both strategies will be evaluated and the influence of general machining and robot specific parameters will be discussed.

  15. Semi-industrial simulation of hot rolling and controlled cooling of Mn-Al TRIP steel sheets

    Directory of Open Access Journals (Sweden)

    A. Grajcar

    2013-03-01

    Full Text Available Purpose: The aim of the work is a semi-industrial physical simulation of thermomechanical rolling and controlled cooling of advanced high-strength steels with increased Mn and Al content.Design/methodology/approach: Four steels of various Mn and Nb concentration were thermomechanically rolled in 3 and 5 passes using a modern LPS line for physical simulation of hot rolling at a semi-industrial scale. The hot deformation course is fully automated as well as controlled cooling applied directly after finishing rolling. Temperature-time and force-energetic parameters of hot rolling were continuously registered and assessed.Findings: The applied line consisting of two-high reversing mill, roller tables with heating panels, cooling devices and controlling-recording systems reflects industrial hot strip rolling parameters sufficiently. Reduction values and temperature-time regimes are similar to those used in industrial practice whereas strain rate is limited to about 10 s-1 what requires taking into account during comparison. All the steels investigated have high total pressure forces due to the high total content of alloying elements. The critical factor making it possible to obtain high-quality sheet samples with a thickness up to 3.3 mm is applying isothermal heating panels which decrease a cooling rate of thin sheets.Research limitations/implications: The real complete simulation of hot strip rolling requires extension of a used line with a further module for simulation of continuous finishing rolling stages. The work is in progress.Practical implications: The results can be successfully utilized in industrial hot rolling and controlled cooling practices after necessary modifications.Originality/value: The efficient semi-industrial physical simulation of hot strip thermomechanical rolling of some new model AHSS grades containing increased Mn and Al content as well as Nb microadditions was presented.

  16. Rolling Tachyon in Nonlocal Cosmology

    OpenAIRE

    Joukovskaya, L.

    2007-01-01

    Nonlocal cosmological models derived from String Field Theory are considered. A new method for constructing rolling tachyon solutions in the FRW metric in two field configuration is proposed and solutions of the Friedman equations with nonlocal operator are presented. The cosmological properties of these solutions are discussed.

  17. Roll bonding of strained aluminium

    DEFF Research Database (Denmark)

    Staun, Jakob M.

    2003-01-01

    This report investigates roll bonding of pre-strained (å ~ 4) aluminium sheets to produce high strain material from high purity aluminium (99.996%) and commercial pure aluminium (99.6%). The degree of bonding is investigated by optical microscopy and ultrasonic scanning. Under the right circumstances both materials show good bonding, but the high purity material is excluded because of recrystallisation and the resulting loss of mechanical properties. The effect of cross stacking and roll bonding pre-strained sheets of the commercial purity material is investigated and some dependence of the cross rolled volume fraction is found. To further asses this effect, and the anisotropy, it is necessary to acquire knowledge about both texture and microstructure, e.g. by TEM. Roll bonding of pre-strained aluminium is found to be a possible alternative to ARB in the quest for ultra-fine grained materials. With deeper knowledge of the parameters at play it will be possible to tailor the properties of the material produced. This combined with the potential for production of bulk material, could make the process an interesting alternative to other methods of producing high strained material.

  18. Nitrofurantoin enteric pellets with high bioavailability based on aciform crystalline formation by wet milling.

    Science.gov (United States)

    Yu, Hongxia; Pan, Lei; Li, Pucheng; Zhang, Keru; Lin, Xia; Zhang, Yu; Tang, Xing

    2015-06-01

    The aim of the present study was to grind nitrofurantoin (NF) with HPMC solution and to determine the dissolution and bioavailability of the enteric pellets prepared with the NF cogrounds and other excipients. During milling, crystalline transformation occurred - the aciform microcrystalline monohydrate II replaced the coarse crystal anhydrate ? and the particle size markedly reduced. In vitro test demonstrated that the enteric pellets prepared with NF cogrounds (4?h) revealed a faster dissolution than the commercial tablet and 50% was released within 30?min in the basic medium. Finally, an in vivo test was conducted in beagle dogs. The Cmax and AUC(0?24) of the pellets were 2.19?±?0.74??g/ml and 6.73?±?4.71??g/ml?h, respectively, while the corresponding values were 0.49?±?0.42??g/ml and 1.38?±?1.17??g/ml?h for the tablet. Thus, the bioavailability of the pellets was increased significantly. In conclusion, the wet grinding that reduced the particle size and created the microcrystalline played a major role in the acceleration of the dissolution of NF and, consequently, enhanced the bioavailability, and the wet grinding process offers an alternative approach to improve the dissolution and bioavailability of drugs with poor aqueous solubility. PMID:24467214

  19. 76 FR 34101 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia

    Science.gov (United States)

    2011-06-10

    ...Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and...rolled flat-rolled carbon-quality steel products from Russia would be likely...hot-rolled flat-rolled carbon-quality steel products from Brazil and...

  20. Laboratory simulation of seamless tube piercing and rolling using dynamic recrystallization schedules

    Science.gov (United States)

    Pussegoda, L. N.; Yue, S.; Jonas, J. J.

    1990-01-01

    A seamless tube mill rolling process was simulated with the aim of designing alloys and schedules for the production of as-hot-rolled yield strength levels which are currently attained only by quenching and tempering. Tests were performed on four candidate Ti-V-N steels with two levels each of carbon (0.10 and 0.18 wt pct) and vanadium (0.10 and 0.16 wt pct). Two different types of schedule were used: (1) a high-temperature schedule, corresponding to the production of large tube diameters, which utilizes the principles of recrystallization-controlled rolling (RCR) and (2) a second (for small tubes), which relies on dynamic recrystallization-controlled rolling (DRCR). The DRCR schedule, together with the higher cooling rate achievable on the smaller tube sizes, produces a much finer ferrite grain size than the RCR schedule. However, this is largely offset by increased strengthening in the RCR structure via precipitation hardening. As-hot-rolled yield strengths in the range of 483 to 715 MPa (70 to 104 ksi) can be achieved using either type of schedule.

  1. Application of powder metallurgy and hot rolling processes for manufacturing aluminum/alumina composite strips

    International Nuclear Information System (INIS)

    In this study, aluminum matrix composites (AMC) with 2, 4, 6 and 10 wt% alumina were produced using powder metallurgy (PM), mechanical milling (MM) and vacuum hot pressing (VHP) techniques; then, this was followed by the hot-rolling process. During hot rolling, AMCs with 6 and 10 wt% Al2O3 were fractured whereas strip composites with 2 and 4 wt% Al2O3 were produced successfully. Microstructure and mechanical properties of the samples were investigated by optical and scanning electron microscopes and tensile and hardness tests, respectively. Microscopic evaluations of the hot-rolled composites showed a uniform distribution of alumina particles in the aluminum matrix. It was found that with increasing alumina content in the matrix, tensile strength (TS) and hardness increased and the percentage of elongation also decreased. Scanning electron microscope (SEM) was used to investigate aluminum/alumina interfaces and fracture surfaces of the hot rolled specimens after tensile test. SEM observations demonstrated that the failure mode in the hot-rolled Al-2 wt% Al2O3 composite strips is a typical ductile fracture, while the failure mode was shear ductile fracture with more flat surfaces in Al-4 wt% Al2O3 strips.

  2. Roll-to-roll fabrication of polymer solar cells

    Directory of Open Access Journals (Sweden)

    Roar Søndergaard

    2012-01-01

    Full Text Available As the performance in terms of power conversion efficiency and operational stability for polymer and organic solar cells is rapidly approaching the key 10–10 targets (10 % efficiency and 10 years of stability the quest for efficient, scalable, and rational processing methods has begun. The 10–10 targets are being approached through consistent laboratory research efforts, which coupled with early commercial efforts have resulted in a fast moving research field and the dawning of a new industry. We review the roll-to-roll processing techniques required to bring the magnificent 10–10 targets into reality, using quick methods with low environmental impact and low cost. We also highlight some new targets related to processing speed, materials, and environmental impact.

  3. Almost rolling motion: An investigation of rolling grooved cylinders

    CERN Document Server

    Mead, L R; Mead, Lawrence R.; Bentrem, Frank W.

    1998-01-01

    We examine the dynamics of cylinders that are grooved to form N teeth for rolling motion down an inclined plane. The grooved cylinders are experimentally found to reach a terminal velocity. This result can be explained by the inclusion of inelastic processes which occur whenever a tooth hits the surface. The fraction of the angular velocity that is lost during an inelastic collision is phenomenologically found to be proportional to (2*sin^2*pi/N)-(alpha*sin^3*pi/N), and the method of least squares is used to find the constant alpha=0.98. The adjusted theoretical results for the time of rolling as well as for terminal velocity are found to be in good agreement with the experimental results.

  4. High speed electrical measurement for roll-to-roll nanomanufacturing

    Science.gov (United States)

    Orloff, Nathan; Long, Christian; Obrzut, Jan; Maillaud, Laurent; Mirri, Francesca; Kole, Thomas; McMichael, Robert; Pasquali, Matteo; Stranick, Stephan; Liddle, J. Alexander

    2015-03-01

    Roll-to-roll processing of nanomaterials can produce high-quality coatings and filaments continuously, enabling materials applications for electronics, fabrics, and wires. These applications often require specific electrical properties that are correlated to the material's nanostructure. While several high-throughput structural characterizations techniques exist, there are relatively few contactless options for quantifying the electrical properties of materials for nanomanufacturing. Here, we demonstrate a microwave method for measuring complex permittivity (or geometry for samples of known dielectric properties) in a millisecond. The demonstrated measurement times are suitable for current industrial needs, allowing real-time materials characterization and in-line control of processing variables without disrupting production. Address correspondence to Dr. Stephan J. Stranick, and Dr. J. Alexander Liddle.

  5. A review of roll-to-roll nanoimprint lithography

    Science.gov (United States)

    Kooy, Nazrin; Mohamed, Khairudin; Pin, Lee Tze; Guan, Ooi Su

    2014-06-01

    Since its introduction in 1995, nanoimprint lithography has been demonstrated in many researches as a simple, low-cost, and high-throughput process for replicating micro- and nanoscale patterns. Due to its advantages, the nanoimprint lithography method has been rapidly developed over the years as a promising alternative to conventional nanolithography processes to fulfill the demands generated from the recent developments in the semiconductor and flexible electronics industries, which results in variations of the process. Roll-to-roll (R2R) nanoimprint lithography (NIL) is the most demanded technique due to its high-throughput fulfilling industrial-scale application. In the present work, a general literature review on the various types of nanoimprint lithography processes especially R2R NIL and the methods commonly adapted to fabricate imprint molds are presented to provide a clear view and understanding on the nanoimprint lithography technique as well as its recent developments.

  6. Methods for estimating radioactive and toxic airborne source terms for uranium milling operations

    International Nuclear Information System (INIS)

    Methods were identified and evaluated for estimating radioactive and toxic particulate and gaseous airborne releases from uranium milling operations. Such methods need to be standardized so that all uranium mills can provide adequate data for NRC evaluation of potential environmental impacts and of compliance with 10 CFR 20, 40 CFR 190, and the National Environmental Policy Act. The general method for calculating source terms is to multiply together a normalized emission rate, contaminant content, emission control factor, and processing rate for each process being evaluated. This report describes the sources of airborne releases (ore storage area, ore crushing and grinding, ore processing, yellowcake production, and tailings impoundment) and the calculational procedures for estimating radioactive and toxic source terms. Example calculations are provided. 27 refs., 4 figs., 9 tabs

  7. In-situ roundness measurement and correction for pin journals in oscillating grinding machines

    Science.gov (United States)

    Yu, Hongxiang; Xu, Mengchen; Zhao, Jie

    2015-01-01

    In the mass production of vehicle-engine crankshafts, pin chasing grinding using oscillating grinding machines is a widely accepted method to achieve flexible and efficient performance. However, the eccentric movement of pin journals makes it difficult to develop an in-process roundness measurement scheme for the improvement of contour precision. Here, a new in-situ roundness measurement strategy is proposed with high scanning speed. The measuring mechanism is composed of a V-block and an adaptive telescopic support. The swing pattern of the telescopic support and the V-block is analysed for an equal angle-interval signal sampling. Hence roundness error signal is extracted in frequency domain using a small-signal model of the V-block roundness measurement method and the Fast Fourier Transformation. To implement the roundness data in the CNC coordinate system of an oscillating grinding machine, a transformation function is derived according to the motion model of pin chasing grinding methodology. Computer simulation reveals the relationship between the rotational position of the crankshaft component and the scanning angle of the displacement probe on the V-block, as well as the influence introduced by the rotation centre drift. Prototype investigation indicates the validity of the theoretical analysis and the feasibility of the new strategy.

  8. The development of an open architecture control system for CBN high speed grinding

    Scientific Electronic Library Online (English)

    E. Jannone da, Silva; M., Biffi; J. F. G. de, Oliveira.

    2004-03-01

    Full Text Available The aim of this project is the development of an open architecture controlling (OAC) system to be applied in the high speed grinding process using CBN tools. Besides other features, the system will allow a new monitoring and controlling strategy, by the adoption of open architecture CNC combined wit [...] h multi-sensors, a PC and third-party software. The OAC system will be implemented in a high speed CBN grinding machine, which is being developed in a partnership between the University of São Paulo (USP - Manufacturing Processes Optimizing Group (OPF) - NUMA - EESC; and a traditional Brazilian grinding machine manufacturer. This new CNC generation allows the implementation of new monitoring and controlling strategies due to the two-way CNC and PC communication using a High Speed Serial Bus (HSSB). As a result, third-party software routines, such as LabVIEW VIs (Virtual Instruments), can be used to act in the CNC, interacting with HMI software, via Active X. As a result, the performance of high speed grinding can be increased by the adoption of the open architecture controlling solution combined with high performance monitoring systems.

  9. The distribution of microcomponents of organic matter in fuel shales in the grinding process

    Energy Technology Data Exchange (ETDEWEB)

    Lishtvan, I.I.; Zenkov, V.S.; Zhukov, V.K.

    1983-01-01

    It is shown that with grinding of fuel shale, a selective distribution occurs of the organic matter by granulometric fractions. A study of the latter using a thermal analysis method points to the fact that sapropel organic matter is concentrated in the large fractions, while humite and sapropel type fractions are concentrated in the finer ones.

  10. Determining the optimum process parameter for grinding operations using robust process

    Energy Technology Data Exchange (ETDEWEB)

    Neseli, Suley Man; Asilturk, Ilhan; Celik, Levent [Univ. of Selcuk, Konya (Turkmenistan)

    2012-11-15

    We applied combined response surface methodology (RSM) and Taguchi methodology (TM) to determine optimum parameters for minimum surface roughness (Ra) and vibration (Vb) in external cylindrical grinding. First, an experiment was conducted in a CNC cylindrical grinding machine. The TM using L{sup 27} orthogonal array was applied to the design of the experiment. The three input parameters were workpiece revolution, feed rate and depth of cut; the outputs were vibrations and surface roughness. Second, to minimize wheel vibration and surface roughness, two optimized models were developed using computer aided single objective optimization. The experimental and statistical results revealed that the most significant grinding parameter for surface roughness and vibration is workpiece revolution followed by the depth of cut. The predicted values and measured values were fairly close, which indicates 2 ( 94.99 R{sup 2Ra}=and 2 92.73) R{sup 2Vb}=that the developed models can be effectively used to predict surface roughness and vibration in the grinding. The established model for determination of optimal operating conditions shows that a hybrid approach can lead to success of a robust process.

  11. 13C and 15N isotopic data on grinding stones from the Guvecinkayasi site, Turkey.

    Czech Academy of Sciences Publication Activity Database

    Pavl?, Ivan; Gülçur, S.; Ja?ková, I.; Buzek, F.

    2009-01-01

    Ro?. 17, - (2009), s. 19-30. ISBN 2-906053-93-7. ISSN 1018-1946 R&D Projects: GA AV ?R IAA800020701 Institutional research plan: CEZ:AV0Z80020508 Keywords : Chalcolithic * grinding stones * Turkey Subject RIV: AC - Archeology, Anthropology, Ethnology

  12. Improving iodine homogeneity in NIST SRM 1548a Typical Diet by cryogenic grinding.

    Czech Academy of Sciences Publication Activity Database

    Ku?era, Jan; Kameník, Jan

    2015-01-01

    Ro?. 20, ?. 3 (2015), s. 189-194. ISSN 0949-1775 R&D Projects: GA ?R(CZ) GBP108/12/G108 Institutional support: RVO:61389005 Keywords : Iodine * reference material * NIST SRM 1548a * cryogenic grinding * homogeneity Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.048, year: 2013

  13. Cryogenics and its application with reference to spice grinding: a review.

    Science.gov (United States)

    Balasubramanian, S; Gupta, Manoj Kumar; Singh, K K

    2012-01-01

    Cryogenics is the study of very low temperature and its application on different materials including biological products. Cryogenics has numerous applications in space science, electronics, automobiles, the manufacturing industry, sports and musical instruments, biological science and agriculture, etc. Cryogenic freezing finds pivotal application in food, that is, spices and condiments. Although there is a wide range of cryogens to produce the desired low temperature, generally liquid nitrogen (LN?) is used in food grinding. The application of low temperature shows a promising pathway to produce higher quality end product with higher flavor and volatile oil retention. Cryogenic grinders generally consist of precoolers and grinder with the cryogen distribution system. In such grinding systems, cryogens subject the raw material up to or lower than glass transition temperature before it is ground, thus eliminating much of the material and quality hassles of traditional grinding. At present, the capital investment including cryogen and handling costs escalate the final cost of the product. Thus, for large-scale production, a proper design to optimize and make it feasible is the need of the hour and understanding the behavior of different food materials at these low temperature conditions. This article reviews the scenario and application of cryogenics in different sectors, especially to spice grinding. PMID:22698269

  14. STIMULATION OF PROCESS OF MUNERAL POWDER GRINDING THROUGH INTRODUCTION OF ADMIXTURES

    Directory of Open Access Journals (Sweden)

    Tarasov Roman Viktorovich

    2012-10-01

    Full Text Available The status of nanotechnologies in material science predetermines development of nanotechnology-intensive products that demonstrate pre-set properties of modified materials. The presence of nano-size particles of substances makes it possible to benefit from their physical and chemical potential and to overcome some negative developments that accompany the structure formation process (at interphase boundaries. The barrier properties are variable, which is quite important in terms of the increase of the asphalt concrete durability. Production of a modifier (that has nano-particles of the pre-set chemical composition to be added into asphalt concrete mixes is also of interest. The authors present their findings concerning the nano-scale modifier that has a chemically inert component and a hydraulically active substance. The method of de-aggregation is used to produce the nano-scale modifier. By-products are often welcomed as mineral components of the asphalt concrete, as they reduce its cost. The findings of the authors concerning the influence of the grinding mode on the integrated characteristics of the powder are presented in the paper. It is proven than dependence of integrated dispersion indicators is nonlinear due to processes leading to aggregation of mineral powder particles. The analysis of the experimental data collected in the course of "wet" grinding proves that surface-active substances stimulate the process of grinding. The type and concentration of an additive that improves the grinding efficiency is also identified.

  15. Two solvent grinding sonication method for the synthesis of two-dimensional tungsten disulphide flakes.

    Science.gov (United States)

    Carey, Benjamin J; Daeneke, Torben; Nguyen, Emily P; Wang, Yichao; Ou, Jian Zhen; Zhuiykov, Serge; Kalantar-zadeh, Kourosh

    2015-03-01

    Two-dimensional tungsten disulphide flakes are developed via a two solvent grinding assisted liquid phase exfoliation method. Our investigations show the distinct advantages of this approach that include reduced residues of the solvent used, high yield and creating relatively thin flakes suitable for electronic, optical, catalytic and energy storage applications. PMID:25647365

  16. Fatigue Behavior of Friction Stir-Welded Joints Repaired by Grinding

    Science.gov (United States)

    Vidal, C.; Infante, V.

    2014-04-01

    Fatigue is undoubtedly the most important design criterion in aeronautic structures. Although friction stir-welded joints are characterized by a high mechanical performance, they can enclose some defects, especially in their root. These defects along with the relatively low residual stresses of the friction stir-welding thermomechanical cycle can turn into primary sources of crack initiation. In this context, this article deals with the fatigue behavior of friction stir-welded joints subjected to surface smoothing by grinding improvement technique. The 4-mm-thick aluminum alloy 2024-T351 was used in this study. The fatigue strength of the base material, joints in the as-welded condition, and the sound and defective friction stir-welded joints improved by grinding were investigated in detail. The tests were carried out with a constant amplitude loading and with a stress ratio of R = 0. The fatigue results show that an improvement in fatigue behavior was obtained in the joints repaired by superficial grinding technique. The weld grinding technique is better especially for lower loads and increases the high cycle fatigue strength. The fatigue strength of the improved welded joints was higher than that of the base material.

  17. Challenges associated with the design of underground grinding plant at McArthur River project

    International Nuclear Information System (INIS)

    McArthur River is an unique high grade uranium underground mine. Ore grinding and thickening are part of the underground operation. The grinding circuit is designed to operate in conditions different from conventional plant environments. Design of the grinding plant was a collective effort of a multi-disciplinary engineering team closely cooperating with project operating personnel. The equipment had to be selected to reflect widely varying ore properties. A user-friendly plant layout provides access to equipment inspections, services, and the delivery of necessary components. The size of the grinding chamber was limited in order to keep the rock stress levels within allowable values. All underground equipment brought to the construction site was restricted in size and weight. Plant construction faced limited storage space underground, tight erection sequencing, and schedule. Plant ventilation is a critical design feature. It efficiently removes radioactive dust from work areas, eliminates stagnant air pockets, and separates clean air from contaminated air areas. Radiation shielding on the equipment is designed to correspond with operational and maintenance functions. Plant operation is remotely controlled and requires little attendance. Video cameras are used on critical equipment and in controlled access areas. An extensive program of preventive and predictive maintenance allows highly reliable plant operation. (author)

  18. Single Side Electrolytic In-Process Dressing (ELID) Grinding with Lapping Kinematics of Silicon Carbide

    Science.gov (United States)

    Khoshaim, Ahmed Bakr

    The demand for Silicon Carbide ceramics (SiC) has increased significantly in the last decade due to its reliable physical and chemical properties. The silicon carbide is widely used for aerospace segments in addition to many uses in the industry. Sometimes, a single side grinding is preferable than conventional grinding, for it has the ability to produce flat ceramics. However, the manufacturing cost is still high because of the high tool wear and long machining time. Part of the solution is to use electrolytic in process dressing (ELID) to reduce the processing time. The study on ELID single side grinding of ceramics has never been attempted before. The study involves four variables with three levels each. One of the variables, which is the eccentricity, is being investigated for the first time on ceramics. A full factorial design, for both the surface roughness and material removal rate, guides to calculate mathematical models that can predict future results. Three grinding wheel mesh sizes are used. An investigation of the influence of different grain size on the results can then be evaluated. The kinematics of the process was studied based on eccentricity in order to optimize the pattern of the diamond grains. The experiment is performed with the assist of the proposed specialized ELID fluid, TRIM C270E.

  19. Grinding Stones and Handstones from the Site of Guvercinkayasi (1996-2002).

    Czech Academy of Sciences Publication Activity Database

    Pavl?, Ivan

    2004-01-01

    Ro?. 25, ?. 1 (2004), s. 429-431, 434, 437. ISSN 1017-7655 R&D Projects: GA ?R GA404/03/0361 Institutional research plan: CEZ:AV0Z8002910 Keywords : grinding stones Subject RIV: AC - Archeology, Anthropology, Ethnology

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

    DEFF Research Database (Denmark)

    Mishin, Oleg; Bay, B.

    2004-01-01

    Microstructure and texture are analyzed through the thickness of two aluminum plates cold-rolled 40% with different roll gap geometries. It is found that both texture and microstructure are strongly affected by the rolling geometry. After rolling with intermediate-size draughts a rolling-type texture is developed throughout the plate thickness. In this case, grains are subdivided by extended planar dislocation boundaries preferentially aligned at an angle of 40 +/- 15degrees to the rolling direction. In the plate rolled with small draughts, shear texture components appear in the intermediate layers. In these layers, extended planar dislocation boundaries are frequently found to be inclined closely to the rolling direction. The subsurface and central layers of this plate exhibit microstructures similar to those in the plate rolled with intermediate draughts. It is suggested that the development of different textures and microstructures at different depths is related to the activation of different slip systems due to through-thickness strain gradients.

  1. Rolls-Royce go Dutch

    Energy Technology Data Exchange (ETDEWEB)

    1981-02-01

    Rolls-Royce Limited, through its industrial and Marine Division, is to supply two Olympus-powered gas-turbine generating sets to the Energy Authorities in the city of The Hague in Holland, as the power source for a combined heat-and-electricity-supply system which has the emphasis on energy conservation. When it becomes operational, the Dutch contract will have an overall efficiency of 73% making it the most-efficient system so far designed using gas turbine plant, capable of producing 77 MWe of electrical power and 60 MW of thermal power. Two gas-fueled Rolls-Royce SK 30 gas-turbine generating sets, with boilers and steam turbines, will give a 44% guaranteed efficiency. The complete unit is scheduled to begin operation by 1982 and will provide power and heat to 1500 homes, a hospital, and government buildings.

  2. Utilization of stellite registered rolls

    International Nuclear Information System (INIS)

    In the time period 2005-2006 the guidance rolls were removed from 129 used control elements of the NPP Brunsbuettel by the Gamma-Service Recycling GmbH (GSR) with the aim to recycle the material for the production of radiation sources. The authors describe the dismantling of the control elements that are made of f stellite registered with about 50% Co-59 (after irradiation Co-60). The 516 guidance rolls had a radioactive inventory of 8E14 Bq. The material was packaged and transported in underwater-boxes in MOSAIK registered /-type containers. The recycling process was performed in the hot cells of the Helmholtz Center Berlin. Rod-type radiation sources (type R38) were produced for industrial application (medical equipment sterilization, radiation-induced polymerization, food industry, etc.)

  3. Microstructural Changes upon Milling of Graphite in Water and Subsequent MWCNT Formation During High Temperature Annealing

    International Nuclear Information System (INIS)

    The method of preparing carbon nanotube (CNT) by milling of graphite particles in water followed by high temperature annealing is proposed and the mechanism discussed. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) line broadening analysis reveal that cleavage of the graphite particles occurs preferentially along the out-of-plane ? bonds. Carbon K-edge near edge X-ray absorption fine structure (NEXAFS) of the milled graphite shows an increased sp3 character of the C=C bonds, but no major bonds rupture in the graphene sheets. The annealing at 1400 deg. C for 4 h of the milled graphite in argon results in formation of multiwalled carbon nanotubes accompanied with a number of coiled and twisted stacks of graphene sheets. The increased structural disorder of the milled graphite and presence of iron contaminations facilitate the rolling up of the cleaved graphene sheets during annealing

  4. Adapting cable grinding technology to the special demands of nuclear power plant demolition

    International Nuclear Information System (INIS)

    The demolition of nuclear plants is making more and more use of cable grinding because of the specific advantages of this technique. The need for a dry dismantling technology causes vastly faster tool wear because of the lack of a matching tool system. Laboratory studies of cable grinding tools used dry on steel structures indicate that higher cutting speeds give rise to lower process forces and tool temperatures. Tool temperatures of up to 200 C were determined thermographically in tools used at cutting speeds of 11 to 33 m/s in 1.4571-type stainless steel and S 355-type structural steel for rates of metal removal of 0.050 to 0.065 m2/h. Wear at these temperatures especially of the rubber coating of the cables has a very negative impact on the attainable service life of the tools used. Studies in which variation of the feed pressure attained rates of metal removal of up to 0.117 m2/h show that the increased abrasion of material has a proportional impact on the resultant process forces and tool temperatures. However, matched cutting speeds can help reduce the thermal load on cable grinding tools. To remove part of the heat produced in the cable grinding tool in dry processing, on the one hand, and avoid recontamination, on the other hand, a novel cooling system has been developed for the cable grinding process. Laboratory studies conducted with the new cooling system prove its efficiency. Tools whose temperatures in dry working had been determineeratures in dry working had been determined to be around 140 C can be cooled down by up to 70 C by means of the cooling system. The tool temperatures achieved in this way can be considered uncritical not only for diamonds but, above all, for the rubber coating of the tool as well. (orig.)

  5. Automatic detection of thermal damage in grinding process by artificial neural network

    Scientific Electronic Library Online (English)

    Fábio Romano Lofrano, Dotto; Paulo Roberto de, Aguiar; Eduardo Carlos, Bianchi; Rogério Andrade, Flauzino; Gustavo de Oliveira, Castelhano; Landry, Pansanato.

    2003-12-01

    Full Text Available Esse trabalho tem por objetivo o desenvolvimento de um sistema inteligente para detecção da queima no processo de retificação tangencial plana através da utilização de uma rede neural perceptron multi camadas, treinada para generalizar o processo e, conseqüentemente, obter o limiar de queima. Em ger [...] al, a ocorrência da queima no processo de retificação pode ser detectada pelos parâmetros DPO e FKS. Porém esses parâmetros não são eficientes nas condições de usinagem usadas nesse trabalho. Os sinais de emissão acústica e potência elétrica do motor de acionamento do rebolo são variáveis de entrada e a variável de saída é a ocorrência da queima. No trabalho experimental, foram empregados um tipo de aço (ABNT 1045 temperado) e um tipo de rebolo denominado TARGA, modelo ART 3TG80.3 NVHB. Abstract in english This work aims to develop an intelligent system for detecting the workpiece burn in the surface grinding process by utilizing a multi-perceptron neural network trained to generalize the process and, in turn, obtnaing the burning threshold. In general, the burning occurrence in grinding process can b [...] e detected by the DPO and FKS parameters. However, these ones were not efficient at the grinding conditions used in this work. Acoustic emission and electric power of the grinding wheel drive motor are the input variable and the output variable is the burning occurrence to the neural network. In the experimental work was employed one type of steel (ABNT-1045 annealed) and one type of grinding wheel referred to as TARGA model ART 3TG80.3 NVHB.

  6. Generalized Slow Roll for Tensors

    CERN Document Server

    Hu, Wayne

    2014-01-01

    The recent BICEP2 detection of degree scale CMB B-mode polarization, coupled with a deficit of observed power in large angle temperature anisotropy, suggest that the slow-roll parameter $\\epsilon_H$, the fractional variation in the Hubble rate per efold, is both relatively large and may evolve from an even larger value on scales greater than the horizon at recombination. The relatively large tensor contribution implied also requires finite matching features in the tensor power spectrum for any scalar power spectrum feature proposed to explain anomalies in the temperature data. We extend the generalized slow-roll approach for computing power spectra, appropriate for such models where the slow-roll parameters vary, to tensor features where scalar features are large. This approach also generalizes the tensor-scalar consistency relation to be between the ratio of tensor and scalar sources and features in the two power spectra. Features in the tensor spectrum are generically suppressed by $\\epsilon_H$ relative tho...

  7. Rolling Contact Fatigue of Ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A [ORNL; Wang, W. [Bournemouth University, Bournemouth, United Kingdom; Wang, Y. [Bournemouth University, Bournemouth, United Kingdom; Hadfield, M. [Bournemouth University, Bournemouth, United Kingdom; Kanematsu, W. [National Institute of Advanced Industrial Science and Technology, Japan; Kirkland, Timothy Philip [ORNL; Jadaan, Osama M. [University of Wisconsin, Platteville

    2006-09-01

    High hardness, low coefficient of thermal expansion and high temperature capability are properties also suited to rolling element materials. Silicon nitride (Si{sub 3}N{sub 4}) has been found to have a good combination of properties suitable for these applications. However, much is still not known about rolling contact fatigue (RCF) behavior, which is fundamental information to assess the lifetime of the material. Additionally, there are several test techniques that are employed internationally whose measured RCF performances are often irreconcilable. Due to the lack of such information, some concern for the reliability of ceramic bearings still remains. This report surveys a variety of topics pertaining to RCF. Surface defects (cracks) in Si{sub 3}N{sub 4} and their propagation during RCF are discussed. Five methods to measure RCF are then briefly overviewed. Spalling, delamination, and rolling contact wear are discussed. Lastly, methods to destructively (e.g., C-sphere flexure strength testing) and non-destructively identify potential RCF-limiting flaws in Si{sub 3}N{sub 4} balls are described.

  8. Comparison between High Chromium Steel and Semi HSS used in Hot Strip Mill Roughing Stands

    OpenAIRE

    Lecomte-Beckers, Jacqueline; Sinnaeve, Mario; Tchuindjang, Jérôme Tchoufack

    2011-01-01

    Two alloys grades for work rolls used in the roughing stand of Hot Strip Mill (HSM) are compared. The first grade known as High Chromium Steel (HCS) is presently the most widely used alloy for such an application, while the second one known as semi-High Speed Steel (semi-HSS) is the new grade developed to improve the overall performance of the work roll in the roughing stands of the HSM. In the present paper, the new semi-HSS grade is studied starting from three chemical compositions closed o...

  9. Rotary ultrasonic elliptical machining for side milling of CFRP: tool performance and surface integrity.

    Science.gov (United States)

    Geng, Daxi; Zhang, Deyuan; Xu, Yonggang; He, Fengtao; Liu, Dapeng; Duan, Zuoheng

    2015-05-01

    The rotary ultrasonic elliptical machining (RUEM) has been recognized as a new effective process to machining circular holes on CFRP materials. In CFRP face machining, the application of grinding tools is restricted for the tool clogging and the machined surface integrity. In this paper, we proposed a novel approach to extend the RUEM process to side milling of CFRP for the first time, which kept the effect of elliptical vibration in RUEM. The experiment apparatus was developed, and the preliminary experiments were designed and conducted, with comparison to conventional grinding (CG). The experimental results showed that when the elliptical vibration was applied in RUEM, a superior cutting process can be obtained compared with that in CG, including providing reduced cutting forces (2-43% decrement), an extended tool life (1.98 times), and improved surface integrity due to the intermittent material removal mechanism and the excellent chip removal conditions achieved in RUEM. It was concluded that the RUEM process is suitable to mill flat surface on CFRP composites. PMID:25708349

  10. On-machine measurement of the grinding wheels' 3D surface topography using a laser displacement sensor

    Science.gov (United States)

    Pan, Yongcheng; Zhao, Qingliang; Guo, Bing

    2014-08-01

    A method of non-contact, on-machine measurement of three dimensional surface topography of grinding wheels' whole surface was developed in this paper, focusing on an electroplated coarse-grained diamond grinding wheel. The measuring system consists of a Keyence laser displacement sensor, a Keyence controller and a NI PCI-6132 data acquisition card. A resolution of 0.1?m in vertical direction and 8?m in horizontal direction could be achieved. After processing the data by LabVIEW and MATLAB, the 3D topography of the grinding wheel's whole surface could be reconstructed. When comparing the reconstructed 3D topography of the grinding wheel's marked area to its real topography captured by a high-depth-field optical digital microscope (HDF-ODM) and scanning electron microscope (SEM), they were very similar to each other, proving that this method is accurate and effective. By a subsequent data processing, the topography of every grain could be extracted and then the active grain number, the active grain volume and the active grain's bearing ration could be calculated. These three parameters could serve as the criterion to evaluate the grinding performance of coarse-grained diamond grinding wheels. Then the performance of the grinding wheel could be evaluated on-machine accurately and quantitatively.

  11. The grinding of uranium dioxide from fluidized beds; Estudio del m icronizado del UO{sub 2} procedente de lechos Fluidizados

    Energy Technology Data Exchange (ETDEWEB)

    Alonso Folgueras, J. A.

    1974-07-01

    This work deals with the UO{sub 2} vibratory grinding, the UO{sub 2} obtained from fluidized beds. In this study the grinding time has been correlated with surface area, stoichiometry, granulometry and grinded product contamination. The efficiency losses in the grinding of moisten UO{sub 2} are outlined. Finally it is made a brief study of the granulate obtained from the grinded UO{sub 2} as well as the green pellets resulting from it, taking into consideration the dispersion of its density and height. (Author)

  12. Optimizing the control system of cement milling: process modeling and controller tuning based on loop shaping procedures and process simulations

    Scientific Electronic Library Online (English)

    D. C., Tsamatsoulis.

    2014-03-01

    Full Text Available Based on a dynamical model of the grinding process in closed circuit mills, efficient efforts have been made to optimize PID controllers of cement milling. The process simulation is combined with an autoregressive model of the errors between the actual process values and the computed ones. Long term [...] industrial data have been used to determine the model parameters. The data include grinding of various cement types. The M - Constrained Integral Gain Optimization (MIGO) loop shaping method is utilized to determine PID sets satisfying a certain robustness constraint. The maximum sensitivity is considered as such a criterion. Both dynamical parameters and PID sets constitute the inputs of a detailed simulator which involves all the main process characteristics. The simulation is applied over all the PID sets aiming to find the parameter region that provides the minimum integral of absolute error, which functions as a performance criterion. For each cement type a PID set is selected and put in operation in a closed circuit cement mill. The performance of the regulation is evaluated after a sufficient time period, concluding that the developed design combining criteria of both robustness and performance leads to PID controllers of high efficiency.

  13. Recobrimentos de poli (tereftalato de etileno) depositados em aço por aspersão térmica a partir de pós obtidos em diferentes condições de moagem / Thermally sprayed coated carbon steel produced using PET powder obtained in different grinding conditions

    Scientific Electronic Library Online (English)

    Luciana Tavares, Duarte; Vanessa de Freitas Cunha, Lins; César, Mariano; José Roberto Tavares, Branco; Magno Pinto, Collares; Roberto, Galery.

    2003-07-01

    Full Text Available Neste trabalho foram analisados recobrimentos de poli(tereftalato de etileno), PET, depositados em aço carbono através da técnica de aspersão térmica à combustão, e produzidos a partir de pós oriundos de processos de moagem, em moinho de bolas e de facas, de garrafas de PET pós-consumo. Algumas cond [...] ições de moagem foram testadas, tendo-se obtido pós com diferentes características morfológicas. As características morfológicas dos pós e dos recobrimentos foram avaliadas por microscopia óptica e eletrônica, tendo-se observado que o recobrimento apresentava bolhas, provavelmente devido à degradação do polímero. Além disto, os recobrimentos produzidos, bem como as amostras de pó, foram caracterizados por espectroscopia na região do infravermelho, por calorimetria exploratória diferencial e através da determinação de viscosidade intrínseca em solução. Os resultados obtidos mostraram que é possível a produção de aço carbono recoberto com PET através da técnica de aspersão térmica, sendo que o grau de degradação, a morfologia e a distribuição granulométrica dos pós utilizados influenciaram significativamente as características e propriedades dos recobrimentos formados. Abstract in english The main purpose of this work was to study the production of a thermal spray coated poly(ethyleneterephthalate) steel. Poly(ethylene terephthalate) coatings were made of a thin grinding waste produced by a PET recycling company, and of a PET powder, which was obtained by grinding post-consumer bever [...] age bottles. Some grinding conditions, using a ceramic ball mill, were studied. Scanning Electronic Microscopy (SEM) and optical microscopy (OM) were used in the study of powder and coating morphologies, and this analysis showed that PET coating presents bubbles due to polymer degradation. PET powder and coating characteristics were investigated using Differential Scanning Calorimetry (DSC) and measurements of intrinsic viscosity. It was observed that the powder morphology and the degradation and the size distribution of the PET powder affect significantly the characteristics and properties of coatings.

  14. Recobrimentos de poli (tereftalato de etileno depositados em aço por aspersão térmica a partir de pós obtidos em diferentes condições de moagem Thermally sprayed coated carbon steel produced using PET powder obtained in different grinding conditions

    Directory of Open Access Journals (Sweden)

    Luciana Tavares Duarte

    2003-07-01

    Full Text Available Neste trabalho foram analisados recobrimentos de poli(tereftalato de etileno, PET, depositados em aço carbono através da técnica de aspersão térmica à combustão, e produzidos a partir de pós oriundos de processos de moagem, em moinho de bolas e de facas, de garrafas de PET pós-consumo. Algumas condições de moagem foram testadas, tendo-se obtido pós com diferentes características morfológicas. As características morfológicas dos pós e dos recobrimentos foram avaliadas por microscopia óptica e eletrônica, tendo-se observado que o recobrimento apresentava bolhas, provavelmente devido à degradação do polímero. Além disto, os recobrimentos produzidos, bem como as amostras de pó, foram caracterizados por espectroscopia na região do infravermelho, por calorimetria exploratória diferencial e através da determinação de viscosidade intrínseca em solução. Os resultados obtidos mostraram que é possível a produção de aço carbono recoberto com PET através da técnica de aspersão térmica, sendo que o grau de degradação, a morfologia e a distribuição granulométrica dos pós utilizados influenciaram significativamente as características e propriedades dos recobrimentos formados.The main purpose of this work was to study the production of a thermal spray coated poly(ethyleneterephthalate steel. Poly(ethylene terephthalate coatings were made of a thin grinding waste produced by a PET recycling company, and of a PET powder, which was obtained by grinding post-consumer beverage bottles. Some grinding conditions, using a ceramic ball mill, were studied. Scanning Electronic Microscopy (SEM and optical microscopy (OM were used in the study of powder and coating morphologies, and this analysis showed that PET coating presents bubbles due to polymer degradation. PET powder and coating characteristics were investigated using Differential Scanning Calorimetry (DSC and measurements of intrinsic viscosity. It was observed that the powder morphology and the degradation and the size distribution of the PET powder affect significantly the characteristics and properties of coatings.

  15. The grinding tip of the sea urchin tooth exhibits exquisite control over calcite crystal orientation and Mg distribution

    OpenAIRE

    Ma, Yurong; Aichmayer, Barbara; Paris, Oskar; Fratzl, Peter; Meibom, Anders; Metzler, Rebecca A.; Politi, Yael; Addadi, Lia; Gilbert, P. U. P. A.; Weiner, Steve

    2009-01-01

    The sea urchin tooth is a remarkable grinding tool. Even though the tooth is composed almost entirely of calcite, it is used to grind holes into a rocky substrate itself often composed of calcite. Here, we use 3 complementary high-resolution tools to probe aspects of the structure of the grinding tip: X-ray photoelectron emission spectromicroscopy (X-PEEM), X-ray microdiffraction, and NanoSIMS. We confirm that the needles and plates are aligned and show here that even the high Mg polycrystall...

  16. Focused ion beam fabrication of field-ion microscope specimens from mechanically milled pearlitic steel powder.

    Science.gov (United States)

    Ohsaki, Satoru; Hono, Kazuhiro; Hidaka, Hideyuki; Takaki, Setsuo

    2004-01-01

    Sharp needle-like specimens for atom-probe field-ion microscope (APFIM) analysis have been prepared successfully from mechanically milled pearlitic steel powders. Mechanically milled powders were packed in a stainless steel tube with carbonyl steel powders and then consolidated by sheath cold-rolling to obtain a bulk composite. A small square rod was cut out from the bulk and electropolished to a blunt needle. It was then fabricated to a nanometre-sized needle by a focused ion beam technique using an annular gallium ion beam. The tip radius of the specimen was <50 nm, which is suitable for use in APFIM. PMID:15582960

  17. Yang-Mills thermodynamics

    OpenAIRE

    Hofmann, Ralf

    2007-01-01

    We present a quantitative analysis of Yang-Mills thermodynamics in 4D flat spacetime. The focus is on the gauge group SU(2). Results for SU(3) are mentioned in passing. Although all essential arguments and results were reported elsewhere we summarize them here in a concise way and offer a number of refinements and some additions.

  18. ROLL OUT THE TALENT : Final project report

    OpenAIRE

    Eerola, Tuomas; Tuominen, Pirjo; Hakkarainen, Riitta-liisa; Laurikainen, Marja; Mero, Niina

    2014-01-01

    The ROLL OUT THE TALENT project was born out of the desire to recognise and support the strengths of vocational students and to develop new and innovative operating models. ROLL OUT THE TALENT promoted regional cooperation between institutes and companies. The project produced operating and study path models that take into consideration the individual strengths of vocational students and the principles of lifelong learning. This is the final report of the ROLL OUT THE TALENT project, and ...

  19. Angular analysis of the cyclic impacting oscillations in a robotic grinding process

    Science.gov (United States)

    Rafieian, Farzad; Girardin, François; Liu, Zhaoheng; Thomas, Marc; Hazel, Bruce

    2014-02-01

    In a robotic machining process, a light-weight cutter or grinder is usually held by an articulated robot arm. Material removal is achieved by the rotating cutting tool while the robot end effector ensures that the tool follows a programmed trajectory in order to work on complex curved surfaces or to access hard-to-reach areas. One typical application of such process is maintenance and repair work on hydropower equipment. This paper presents an experimental study of the dynamic characteristics of material removal in robotic grinding, which is unlike conventional grinding due to the lower structural stiffness of the tool-holder robot. The objective of the study is to explore the cyclic nature of this mechanical operation to provide the basis for future development of better process control strategies. Grinding tasks that minimize the number of iterations to converge to the target surface can be better planned based on a good understanding and modeling of the cyclic material removal mechanism. A single degree of freedom dynamic analysis of the process suggests that material removal is performed through high-frequency impacts that mainly last for only a small fraction of the grinding disk rotation period. To detect these discrete cutting events in practice, a grinder is equipped with a rotary encoder. The encoder's signal is acquired through the angular sampling technique. A running cyclic synchronous average is applied to the speed signal to remove its non-cyclic events. The measured instantaneous rotational frequency clearly indicates the impacting nature of the process and captures the transient response excited by these cyclic impacts. The technique also locates the angular positions of cutting impacts in revolution cycles. It is thus possible to draw conclusions about the cyclic nature of dynamic changes in impact-cutting behavior when grinding with a flexible robot. The dynamics of the impacting regime and transient responses to impact-cutting excitations captured synchronously using the angular sampling technique provide feedback that can be used to regulate the material removal process. The experimental results also make it possible to correlate the energy required to remove a chip of metal through impacting with the measured drop in angular speed during grinding.

  20. A Framework for Rolling Stock Rescheduling

    DEFF Research Database (Denmark)

    Haahr, JØrgen Thorlund; Lusby, Richard Martin

    Rolling Stock schedules are typically made months or weeks prior to the date of execution. It is, however, rare that everything goes exactly as planned due to internal and external factors on the day of operation. If the magnitude of the disturbances is small then the problems may be absorbed by network buffer times. However, if the problems are more severe, changes must be made to the rolling stock schedule. In this talk we will discuss the Rolling Stock Rescheduling problem and Disruption Management. We will present our current work and planned future work on a framework for solving the Rolling Stock in a disruption context.

  1. Europarlamendi roll põllumajanduspoliitika kujundamisel / Andres Tarand

    Index Scriptorium Estoniae

    Tarand, Andres, 1940-

    2006-01-01

    Euroopa Parlamendi roll Euroopa Liidu ühtse põllumajandus- ja energiapoliitika kujundamisel. Põllumajanduslik aspekt energeetikas: energiasektori varustamine omamaa bioenergiaga, Venemaa energeetika välispoliitika teenistuses

  2. Interactions Between Stably Rolling Leukocytes In Vivo

    CERN Document Server

    King, M R; Kim, M B; Sarelius, I H; King, Michael R.; Ruscio, Aimee D.; Kim, Michael B.; Sarelius, Ingrid H.

    2003-01-01

    We have characterized the two-dimensional spatial dependence of the hydrodynamic interactions between two adhesively rolling leukocytes in a live venule in the mouse cremaster muscle. Two rolling leukocytes were observed to slow each other down when rolling together in close proximity, due to mutual sheltering from the external blood flow in the vessel lumen. These results are in agreement with a previous study of leukocyte rolling interactions using carbohydrate-coated beads in a parallel-plate flow chamber and a detailed computer model of adhesion in a multicellular environment.

  3. Force prediction in thread milling

    OpenAIRE

    Araujo A. C.; Silveira J. L.; Kapoor S

    2004-01-01

    A mechanistic approach for modeling the thread milling process is presented. The mechanics of cutting for thread milling is analyzed as an end milling process with modified cutting edge. The geometry of threads is added to the geometry of the end milling tool to calculate the chip load area. The linear path is simulated and values of the specific energy from end milling are used to compute the cutting forces involved. A comparison between the simulation of the cutting forces for a specific to...

  4. Evaluation of End Mill Coatings

    Energy Technology Data Exchange (ETDEWEB)

    L. J. Lazarus; R. L. Hester,

    2005-08-01

    Milling tests were run on families of High Speed Steel (HSS) end mills to determine their lives while machining 304 Stainless Steel. The end mills tested were made from M7, M42 and T15-CPM High Speed Steels. The end mills were also evaluated with no coatings as well as with Titanium Nitride (TiN) and Titanium Carbo-Nitride (TiCN) coatings to determine which combination of HSS and coating provided the highest increase in end mill life while increasing the cost of the tool the least. We found end mill made from M42 gave us the largest increase in tool life with the least increase in cost. The results of this study will be used by Cutting Tool Engineering in determining which end mill descriptions will be dropped from our tool catalog.

  5. Statistical Modeling of Pin Gauge Dimensions of Root of Gas Turbine Blade in Creep Feed Grinding Process

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Fazeli

    2010-09-01

    Full Text Available Creep feed grinding is a recently invented process of material handling. It combines high quality of the piece surface, productivity, and the possibility of automatic control. The main objectives of this research is to study the influences of major process parameters and their interactions of creep feed grinding process such as wheel speed, workpiece speed, grinding depth, and dresser speed on the pin gauge dimensions of root of gas turbine blade by design of experiments (DOE. Experimental results are analyzed by analysis of variance (ANOVA and empirical models of pin gauge dimensions of root are developed. The study found that higher wheel speed along with slower workpiece speed, lower grinding depth and higher dresser speed, cause to obtain best conditions for pin gauge dimensions of root.

  6. Error Compensation of Complex Three-Dimensional Surfaces Machined on Computer-Numeric-Control Grinding Machine Tools

    Directory of Open Access Journals (Sweden)

    M. Raoufinia

    2009-01-01

    Full Text Available This study discusses the development of a method for compensating profile errors, resulting from the deviation of the actual grinding wheel radius from the calculated one. The study also elaborates on a control strategy that may be followed to minimise the profile error and allow the use of a four-axis grinding machine instead of five-axis one to perform the same machining task. This approach can be completely justified when the reduction in the machining cost is achieved as a result of grinding the gauge profile on a four-axis CNC machine tool instead of the five-axis one. When a number of five segments are chosen, the first control program is established for the first mean radius (170 mm of the first segment. When the grinding wheel radius reaches 150 mm as a result of wheel dressing, a new control program that will consider a new nominal radius of 160 mm will be activated.

  7. A new preparation scheme for a difficult-to-float coking coal by column flotation following grinding

    Scientific Electronic Library Online (English)

    Yinfei, Liaoa; Yijun, Caoa; Zhongbo, Hub; Xiuxiang, Taoc.

    2015-02-01

    Full Text Available A new preparation scheme for a difficult-to-float coking coal from the Kailuan Mine, Tangshan, China was investigated. The results showed that grinding followed by column flotation was beneficial for obtaining products with low ash content. The positive effect of grinding on the coal floatability is [...] attributed to the liberation of intergrowths and coal surface improvement. Tests indicated that 10 minutes was the optimum grinding time, and overgrinding resulted in a deterioration in flotation performance. With a grinding time of 10 minutes, conventional flotation had potential to yield a product with around 12.42% ash content and 69.15% combustible recovery. Column flotation can reduce the product ash content to 11.15% and increase combustible recovery to 74.47%. Consistently better flotation results reveal that column flotation is more efficient than conventional flotation for such fines.

  8. The Functional and Symbolic Value of Grinding Stone Tools from the Late Bandkeramik of North-Western Europe

    Directory of Open Access Journals (Sweden)

    Caroline Hamon

    2009-09-01

    Full Text Available The arrival of late LBK populations in north-western Europe (Hainaut, Hesbaye and the Paris Basin was accompanied by a change in the functional and symbolic practices related to grinding stone tools. Contrary to former LBK practices, grinding tools were by this time no longer objects of long-distance exchange or circulation. Instead, they were made quasi-systematically on local sandstones of pretty high quality or on local granites on the western or southern periphery of the sedimentary Paris Basin (Normandy, Yonne. Despite the use of these more local resources, grinding stone tools kept their symbolic value in the late LBK of western Europe. This can be seen in the manner in which individual examples were broken up, hoarded and deposited. This article locates this symbolic value in the association of grinding stones with cereal processing, with categories of people and, more broadly, with an agricultural way of life.

  9. Improving Energy Efficiency Via Optimized Charge Motion and Slurry Flow in Plant Scale Sag Mills

    Energy Technology Data Exchange (ETDEWEB)

    Raj K. Rajamani; Jose Angel Delgadillo

    2006-07-21

    A research team from the University of Utah is working to make inroads into saving energy in these SAG mills. In 2003, Industries of the Future Program of the Department of Energy tasked the University of Utah team to build a partnership between the University and the mining industry for the specific purpose of reducing energy consumption in SAG mills. A partnership was formed with Cortez Gold Mines, Kennecott Utah Copper Corporation, Process Engineering Resources Inc. and Outokumpu Technology. In the current project, Cortez Gold Mines played a key role in facilitating the 26-ft SAG mill at Cortez as a test mill for this study. According to plant personnel, there were a number of unscheduled shut downs to repair broken liners and the mill throughput fluctuated depending on ore type. The University team had two softwares, Millsoft and FlowMod to tackle the problem. Millsoft is capable of simulating the motion of charge in the mill. FlowMod calculates the slurry flow through the grate and pulp lifters. Based on this data the two models were fine-tuned to fit the Cortez SAG will. In the summer of 2004 a new design of shell lifters were presented to Cortez and in September 2004 these lifters were installed in the SAG mill. By December 2004 Cortez Mines realized that the SAG mill is drawing approximately 236-kW less power than before while maintaining the same level of production. In the first month there was extreme cycling and operators had to learn more. Now the power consumption is 0.3-1.3 kWh/ton lower than before. The actual SAG mill power draw is 230-370 kW lower. Mill runs 1 rpm lesser in speed on the average. The recirculation to the cone crusher is reduced by 1-10%, which means more efficient grinding of critical size material is taking place in the mill. All of the savings have resulted in reduction of operating cost be about $0.023-$0.048/ ton. After completing the shell lifter design, the pulp lifter design was taken up. Through a series of mill surveys and model calculations it was figured that the radial pulp lifter installed on the mill had less than optimum discharge capacity. A number of alternative designs were evaluated. The final choice was the Turbo Pulp Lifter for which Outukumpu Technology, Centennial, Colorado had filed a patent. After installation of the pulp lifter a 22% increase in throughput rate from 344 stph to 421 stph was realized. A 35% decrease in the SAG mill power draw from 3,908 HP to 2,526 HP (2,915 kW to 1,884 kW) was recorded. This equates to a 47% decrease in SAG unit energy consumption from 8.98 kWh/ton to 4.74 kWh/ton. A 11% decrease in SAG mill speed was observed indicating optimized ball strikes. Also, the ball chip generation from the SAG mill was reduced considerably. Further more, a 7% decrease in ball mill power draw from 4,843 HP to 4,491 HP (3,613 kW to 3,350 kW) was observed. This equates to a 24% decrease in ball mill unit energy consumption from 11.13 kWh/ton to 8.43 kWh/ton.

  10. Electron backscatter diffraction applied to lithium sheets prepared by broad ion beam milling.

    Science.gov (United States)

    Brodusch, Nicolas; Zaghib, Karim; Gauvin, Raynald

    2015-01-01

    Due to its very low hardness and atomic number, pure lithium cannot be prepared by conventional methods prior to scanning electron microscopy analysis. Here, we report on the characterization of pure lithium metallic sheets used as base electrodes in the lithium-ion battery technology using electron backscatter diffraction (EBSD) and X-ray microanalysis using energy dispersive spectroscopy (EDS) after the sheet surface was polished by broad argon ion milling (IM). No grinding and polishing were necessary to achieve the sufficiently damage free necessary for surface analysis. Based on EDS results the impurities could be characterized and EBSD revealed the microsctructure and microtexture of this material with accuracy. The beam damage and oxidation/hydration resulting from the intensive use of IM and the transfer of the sample into the microscope chamber was estimated to be process generates an increase of temperature at the specimen surface, it was assumed that the milling parameters were sufficient to minimize the heating effect on the surface temperature. However, a cryo-stage should be used if available during milling to guaranty a heating artefact free surface after the milling process. PMID:25280344

  11. Moagem de pós de carbeto de silício em moinho planetário / Planetary milling of silicon carbide powders

    Scientific Electronic Library Online (English)

    M. A. P. dos, Santos; C. A., Costa.

    2005-12-01

    Full Text Available Pó de alfa carbeto de silício (alfa-SiC) foi cominuído em moinho planetário durante os períodos de tempo de ½, 2, 4 e 6 h. A velocidade de rotação foi de 300 rpm, o meio de moagem foi álcool isopropílico e os corpos moedores foram esferas de zircônia estabilizada com céria. Os pós cominuídos foram c [...] aracterizados quanto ao tamanho e distribuição de tamanho de partícula, a composição química, as fases cristalinas e a morfologia. Observou-se uma grande redução no tamanho de partículas, que passaram de micrométricas para submicrométricas e até nanométricas, alteração da distribuição das mesmas de bimodal para unimodal, e a geração de aditivação secundária causada pelo meio de moagem. Abstract in english Alpha silicon carbide (alpha-SiC) powder was comminuted in planetary mill during ½, 2, 4 and 6 h. The rotation speed was 300 rpm, the medium of milling was isopropyl alcohol and the grinding bodies were spheres of ceria-stabilized zirconia. The milling powders were characterized concerning the size [...] and particle size distribution, the chemical composition, the crystalline phases, and morphology. A large reduction of the particle size, that had changed from micrometrics to submicrometrics and even nanometrics, a change of their distribution from bimodal to unimodal, and the generation of secondary aditivation caused by medium of milling were observed.

  12. Moagem de pós de carbeto de silício em moinho planetário Planetary milling of silicon carbide powders

    Directory of Open Access Journals (Sweden)

    M. A. P. dos Santos

    2005-12-01

    Full Text Available Pó de alfa carbeto de silício (alfa-SiC foi cominuído em moinho planetário durante os períodos de tempo de ½, 2, 4 e 6 h. A velocidade de rotação foi de 300 rpm, o meio de moagem foi álcool isopropílico e os corpos moedores foram esferas de zircônia estabilizada com céria. Os pós cominuídos foram caracterizados quanto ao tamanho e distribuição de tamanho de partícula, a composição química, as fases cristalinas e a morfologia. Observou-se uma grande redução no tamanho de partículas, que passaram de micrométricas para submicrométricas e até nanométricas, alteração da distribuição das mesmas de bimodal para unimodal, e a geração de aditivação secundária causada pelo meio de moagem.Alpha silicon carbide (alpha-SiC powder was comminuted in planetary mill during ½, 2, 4 and 6 h. The rotation speed was 300 rpm, the medium of milling was isopropyl alcohol and the grinding bodies were spheres of ceria-stabilized zirconia. The milling powders were characterized concerning the size and particle size distribution, the chemical composition, the crystalline phases, and morphology. A large reduction of the particle size, that had changed from micrometrics to submicrometrics and even nanometrics, a change of their distribution from bimodal to unimodal, and the generation of secondary aditivation caused by medium of milling were observed.

  13. Electrochemical corrosion of grinding media and effect of anions present in industrial waters

    International Nuclear Information System (INIS)

    The steel used in the minerals processing as grinding media (balls or bars), is an important input in terms of cost of the process. Considering the importance of the steel consumption in these processes, this work is guided to evaluate to laboratory scale the effect of the anions present in the industrial waters on the electrochemical corrosion of grinding media. Tests in electrochemical cell, were accomplished measuring potential and corrosion current to four electrodes that were manufactured using sufficiently pure sample of chalcopyrite, bornite, enargite and steel ball. The ions used in the tests were chlorides, sulfates, nitrates and carbonates in concentrations from 1 to 180 ppm in individual form or in mixtures, according to the levels measurement of these in industrial waters. (Author) 10 refs

  14. Utilization of teflon and aluminum oxide for wheel cleaning in Minimum Quantity Lubrication (MQL) grinding

    Scientific Electronic Library Online (English)

    Bianca Gomes, Barros; Tiago da, Silva; Rubens Chinali, Canarim; Paulo Roberto de, Aguiar; Eduardo Carlos, Bianchi.

    2014-02-01

    Full Text Available Researches concerning cooling-lubrication optimization in grinding have been conducted to contribute to a more sustainable process. An alternative to flood coolant is minimum quantity lubrication (MQL), which spray oil droplets in a compressed air jet. However, problems related to wheel cleaning wer [...] e reported, due to wheel loading by a mixture of chips and oil, resulting in worsening of surface quality. This work aims to evaluate the viability of Teflon and aluminum oxide for wheel cleaning, compared to MQL without cleaning and MQL with cleaning by compressed air, through the following output variables: surface roughness, roundness, wheel wear, grinding power and acoustic emission. Vickers microhardness measurements and optical microscopy were also carried out. The results showed that both materials were efficient in cleaning the wheel, compared to MQL without cleaning, but not as satisfactory as compressed air. Much work is to be done in order to select the right material for wheel cleaning.

  15. Influence of grinding procedures on the flexural strength of zirconia ceramics

    Scientific Electronic Library Online (English)

    Ufuk, & #304; & #351; er& #305; ; Zeynep, Özkurt; Ender, Kazazo& #287; lu; Davut, Küçüko& #287; lu.

    Full Text Available A superfície da zircônia pode ser danificada durante o desgaste, influenciando as propriedades mecânicas do material. O objetivo deste estudo foi comparar a resistência à flexão da zircônia após diferentes procedimentos de desgaste. Vinte amostras de zircônia em formato de barra (21x5x2mm) foram div [...] ididos em 4 grupos e desgastados usando uma peça de mão de alta velocidade e um micromotor até as barras terem sido reduzidas 1 mm usando dois tempos diferentes de desgaste: desgaste contínuo e desgaste de curta duração (n=5). Amostras de controle (sem desgaste; n=5) foram analisadas. A resistência à flexão das barras foi determinada utilizando o ensaio de flexäo em três pontos numa máquina universal de ensaios a uma velocidade cruzeta de 0,5 mm/min. A carga de fratura (N) foi registrada, e os dados foram analisados estatisticamente com o teste Kruskal-Wallis com o nível de significância de 0,05. Não houve diferenças estatisticamente significantes entre os grupos (p>0,05). Nos grupos teste, o desgaste de curta duração usando peça de mão de alta velocidade foi o mais alto (878,5 ± 194,8 MPa), e o desgaste contínuo com o micromotor apresentou o valor mais baixo (733,8 ± 94,2 MPa). O grupo controle foi o mais forte (928,4 ± 186,5 MPa). Dentro das limitações do estudo, não houve diferença na resistência à flexão das amostras da zircônia desgastadas com procedimentos diferentes. Abstract in english The surface of zirconia may be damaged during grinding, influencing the mechanical properties of the material. The purpose of this study was to compare the flexural strength of zirconia after different grinding procedures. Twenty bar-type zirconia specimens (21 x 5 x 2 mm) were divided into 4 groups [...] and ground using a high-speed handpiece or a low-speed straight handpiece until the bars were reduced 1 mm using two different grinding times: continuous grinding and short-time grinding (n=5). Control specimens (n=5) were analyzed without grinding. The flexural strengths of the bars were determined by using 3-point bending test in a universal testing machine at a crosshead speed of 0.5 mm/min. The fracture load (N) was recorded, and the data were analyzed statistically by the Kruskal Wallis test at a significance level of 0.05. In the test groups, high-speed handpiece grinding for a short time had produced the highest mean flexural strength (878.5 ± 194.8 MPa), while micromotor continuous grinding produced the lowest mean flexural strength (733.8 ± 94.2 MPa). The control group was the strongest group (928.4 ± 186.5 MPa). However, there was no statistically significant differences among the groups (p>0.05). Within the limitations of the study, there was no difference in flexural strength of zirconia specimens ground with different procedures.

  16. Fatigue life improvement factors obtained by weld reinforcement and toe grinding

    Energy Technology Data Exchange (ETDEWEB)

    Mullen, C.L.; Merwin, J.E.

    1982-01-01

    The potential of weld reinforcement and toe grinding techniques for improving the fatigue life of welded joints protected from seawater corrosion is quantified based on tests performed in air on welded plate specimens. Results are presented in terms of median fatigue life improvement factors and prediction intervals obtained by linear regression analysis. The significant improvements possible with weld reinforcement are shown to be caused partly by a slight alleviation of the stress concentration imposed by sharp angles at the weld toe. Variable improvements observed for toe ground welds are shown to be associated with the variable surface modifications which different tools impose on weld toes. Load and weld geometry are shown to be particulary important when bending stresses are applied to the weld toe, since reinforcement affects the bending moment at the toe section and toe grinding affects the conditions at the highly stressed outer fibers. 14 references.

  17. The accuracy of “subacromial grind test” in diagnosis of supraspinatus rotator cuff tears

    Science.gov (United States)

    Sawalha, Seif; Fischer, Jochen

    2015-01-01

    Purpose: The aim of this study is to assess the accuracy of a simple clinical test (subacromial grind test) in diagnosing supraspinatus tendon tears. Patients and Methods: The test is considered positive if palpable crepitus or grinding is detected on passive internal and external rotation of the shoulder while abducted in the scapular plane. Data were collected prospectively on 47 patients undergoing shoulder arthroscopy, and the results of the test and arthroscopy compared. Results: During arthroscopy, 17 patients had full thickness (FT) tears of supraspinatus tendon and 10 had partial thickness tears. For any supraspinatus tear, the sensitivity of the test was 63%, specificity 95%, positive predictive value 94%, negative predictive value 66% and overall accuracy 79%. For FT tears, the sensitivity was 82%, specificity 87%, positive predictive value 78%, negative predictive value 90% and overall accuracy 85%. Conclusion: We found that this is a useful single test for diagnosing FT supraspinatus tears. Level of Evidence: Level IV diagnostic study. PMID:25937713

  18. Contribuição ao estudo da retificação abrasiva de materiais cerâmicos / Introduction to abrasive grinding of ceramics

    Scientific Electronic Library Online (English)

    H., Fujita; E. C., Bianchi; P. R. de, Aguiar; L. E. de A., Sanchez; C. E. da, Silva Jr..

    2006-12-01

    Full Text Available Uma das principais limitações relacionadas ao processo de retificação de cerâmica é a confiabilidade do material devido aos defeitos introduzidos no processamento. A compreensão dos mecanismos envolvidos na remoção de material durante a retificação e a interação com os parâmetros de processo e micro [...] estrutura é fundamental para minimizar estes defeitos. A proposta desta revisão é apresentar os modelos de remoção de material e a forma como afetam as propriedades mecânicas da peça final. Abstract in english One of the major restrictions in grinding of ceramics is the probability of failure of material due to the damage induced during the process. The understanding of mechanisms of material removal on grinding and the interaction with the process parameters and microstructure is fundamental to minimize [...] these problems. The purpose of this review is to present the models of material removal in ceramics and the way they affect the mechanical properties of the product.

  19. Radiometric study of the flow and distribution behaviour in grinding and flotation plants

    International Nuclear Information System (INIS)

    In addition to the technological description of the process the optimization of apparatuses and plants requires a flow diagram on the basis of the residence time distribution of mass flow in grinding and flotation plants. The transport behaviour of the material in cement clinker grinding was studied in plants of semi-technical and full-technical scale (open and closed circuit) with the aid of radiotracers (24Na, 82Br, 198Au) and continuous measurement characteristic data of the diffusion model were used. On the basis of the cell model the mean residence time and the equivalent number of agitation stages were calculated. The relation to technological parameters (apparatus design, material, grain size) is discussed. (author)

  20. Mill’s Liberal Feminism: Its Legacy and Current Criticism

    Directory of Open Access Journals (Sweden)

    MARIANA SZAPUOVÁ

    2006-12-01

    Full Text Available This paper highlights John Stuart Mill’s views on the problem of gender equality as expressed in The Subjection of Women, which is commonly regarded as one of the core texts of Enlightenment liberal feminism of the 19th century. In this paper, the author outlines the historical context of both Mill’s views and his personal biography, which influenced his argumentation for the emancipation of women, and considers Mill’s utilitarianism and liberalism, as the main philosophical background for his criticism of social conditions that subordinated women. She reflects on some of the philosopher’s ideas and arguments for equality and friendship between women and men which may still be considered noteworthy and relevant. Attention is also given to the main lines of contemporary reception of Mill’s liberal feminism from the perspective of current feminist philosophy, within which certain critical views predominate. Despite some problematic points in Mill’s considerations, his essay on women’s subjection may be regarded as one of the philosophically most interesting conceptions of liberal feminist thinking.