WorldWideScience
1

Design, fabrication and performance analysis of a planetary roll mill for fine grinding  

Directory of Open Access Journals (Sweden)

Full Text Available Reducing milling cost in mineral processing is a problem that has defiled all serious attempts while milling still takes up to 60% of comminution cost. The planetary roll mill is a new innovation for faster and finer grinding. It is designed and fabricated with grinding rolls rotating in a number of arms inside a grinding sphere. A test run of the complete machine with crushed granite and sandstone shows that the machine grinds to fine consistency within a short period of time. A comparison of the products of the machine with that of a standard Denver Laboratory Ball Mill shows that the machine is about 30% more efficient than the ball mill in terms of duration of grinding to a particular size consistency. One advantage of the planetary roll mill is that is can be used as a ball mill if the need arises. It is therefore recommended that this mill be developed for both research and industrial uses.

Ajaka E. O.

2011-04-01

2

Rheology of coal-water slurries prepared by the high-pressure roll mill grinding of coal. Final report  

Energy Technology Data Exchange (ETDEWEB)

The preparation of coal water slurries to replace fuel oil for direct combustion has become an important field in modem coal technology. The U.S. Department of Energy has planned or has underway several demonstration projects to burn coal-water slurries to replace fuel oil is attractive not only because there is an assured domestic supply of coal, but also on various technoeconomic grounds. Coal-water slurries combine the handling flexibility of fuel oil in power plants and various other industrial applications. This report discusses the rheology of coal-water slurries and the correlation to the coal preparation by grinding with a choke-fed high pressure roll mill. Performance of the roll mills and energy consumption are described.

Fuerstenau, D.W.; De, A.

1996-08-01

3

Stress and accidental defect detection on rolling mill rolls  

International Nuclear Information System (INIS)

During the rolling mill process, rolls are submitted to high pressures that can lead to local decohesion or metallurgical changes. Both these cracks or softened areas must be detected as soon as they appear because of the risk of spalling, marks on the product, and mill wreck. These defects can be detected using the eddy current method, and particularly sensors specially developed for micro-defects detection. These sensors must be adapted to the environment of a roll grinding machine on which they must be installed. Users' schedule of conditions also require them to be attached to a wide range of eddy current generator and automatic computerized interpretation. Mill requirements for new high tech roll grades and quality lead to continuous development and improvement of the tools that will provide immediate 'go - no go' information. This paper is an update of these developments. (author)

4

Bimetal rolling in dissimilar diameter mill rolls  

International Nuclear Information System (INIS)

Cold working conditions in St3-Kh18N10T steel bimetal sheet rolling were calculated aimed to prevent delamination. It states that in cold rolling in a mill stand with dissimilar diameter rolls the ratio of roll diameters should be close to that of layer thickness to decrease stresses at the bimetal interface

5

Continuous grinding mill simulation using Austin's model  

Directory of Open Access Journals (Sweden)

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.

Andr\\u00E9 Carlos Silva

2012-01-01

6

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.)

7

Evaluation of Recycle Grinding Performance in Flour Milling  

OpenAIRE

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 ...

Siti Mazlina Mustapa Kamal; Colin Webb

2007-01-01

8

Numerical analysis of grinding power consumption of a vertical planetary mill  

Energy Technology Data Exchange (ETDEWEB)

Planetary wheel rolling on a coal-bed was simplified as rigid wheel rolling on the coal-bed with a rigid base when a vertical planetary mill (VPM) is running. Based on this analysis, it is concluded that the Bekker formulation for computing rolling resistance is not applicable to calculate directly the rolling resistance of the wheel. According to the principle of the Bekker apparatus, pressure-sinkage curves were obtained by tests on a piece of mono-axial consolidation apparatus used in soil-mechanics. The deformation modulus of the coal-bed was calculated using elastic mechanics. A finite element model of the planetary wheel coal-bed was built up by the use of a rigid and a Drucker-Prager material model in LS-DYNA. According to the simulation results, the wheel rolling resistance, the grinding power consumption and the motor power of the mill were calculated and the mistake in the initial design of the mill was modified. The simulation results agree well with the results of the semi-industrial tests. 14 refs., 9 figs., 1 tab.

Xue-di Hao; Dong-mei Zhu; Zhi-rui Bian; Xin Wang [University of Science and Technology Beijing, Beijing (China). School of Mechanical Engineering

2008-06-15

9

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)

10

Evaluation of Recycle Grinding Performance in Flour Milling  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Siti Mazlina Mustapa Kamal

2007-01-01

11

Evaluation of Recycle Grinding Performance in Flour Milling  

Science.gov (United States)

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.

Mazlina Mustapa Kamal, Siti; Webb, Colin

12

[Dehulling of sorghum in grinding mills].  

Science.gov (United States)

The efficiency of the dehulling process of sorghum grain was studied in a laboratory abrasive stone mill. Residual tannins as tannic acid and cathequin equivalent, as well as color measurements of the product were determined as control parameters of the procedure. Besides, fiber, ash and fat contents as well as other variables were evaluated. Assays were performed at three stone speeds and at different operation times. According to the results obtained, a stone speed of 1,700 rpm and a 12-minute period, are the best operating conditions, while measurements of color of the product constitute the best method for controlling the dehulling process. PMID:3435218

Corimayo, J R; Gutiérrez, R R; Gómez, M H

1986-12-01

13

Metallurgical analysis of spalled work roll of hot strip mill  

International Nuclear Information System (INIS)

In this study failure analysis of four work roll of the Hot Strip Mill is carried out. The microstructure is correlated with the chemical composition of shell and roll-life. It was concluded that for the longer service of the roll, cementite, graphite and martensite should be balanced (as per working requirement of the mill). (author)

14

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

OpenAIRE

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.

Łysiak G.; Laskowski J.

1997-01-01

15

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

Science.gov (United States)

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, D50and 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

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

2015-01-01

16

Structural causes of defects in a cast iron mill roll  

OpenAIRE

This paper describes an analysis of a defective microstructure of a mill roll. For this purpose, a piece of a broken roll was collected. That roll was made of mottled cast iron. Its microstructure consisted of modular graphite, transformed ledeburite and a matrix composed of bainite and martensite. Metallographic investigations were performed nearby the fracture in the roll. Observations were conducted on polished sections, first not etched, and then etched, which allowed us to trace carefull...

Krawczyk, J.

2008-01-01

17

Analysis of roll stack deflection in a hot strip mill  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

2007-09-01

18

Technological design for rolling uranium rod by Y-type rolling mill with three rollers  

International Nuclear Information System (INIS)

The fundamental characteristics of Y-type rolling mill with three rollers and the methods for designing and calculating the grooves are described. The feasibility of producing metallic uranium rod is substantiated by the experiment in continuous rolling. The advantage of this process in rolling metallic uranium rod is analysed

19

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...

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

21

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

CERN Document Server

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.

Angleys, M

2003-01-01

22

Corrosion of Cast Iron Mill Plates in Wet Grinding  

OpenAIRE

Corrosion studies were carried out on two different maize grinding plates. Maize was soaked in water for three days and the water decanted and used as electrolyte. Mass loss and pH measurements were carried out every 3 days for 15-day period. Results show that, for each plate, mass loss and pH increased with exposure time. Corrosion rates determined from mass loss data was found to be strongly dependent on pH. The observed behaviour may be explained in terms of the chemical composition and/or...

Andrews, Anthony; Kwofie, Samuel

2010-01-01

23

Corrosion of Cast Iron Mill Plates in Wet Grinding  

Directory of Open Access Journals (Sweden)

Full Text Available Corrosion studies were carried out on two different maize grinding plates. Maize was soaked in water for three days and the water decanted and used as electrolyte. Mass loss and pH measurements were carried out every 3 days for 15-day period. Results show that, for each plate, mass loss and pH increased with exposure time. Corrosion rates determined from mass loss data was found to be strongly dependent on pH. The observed behaviour may be explained in terms of the chemical composition and/or microstructures of the plates. Results are briefly discussed in terms of the contribution of corrosion to wear.

Anthony ANDREWS

2010-12-01

24

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

Scientific Electronic Library Online (English)

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.

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

2010-06-01

25

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

Directory of Open Access Journals (Sweden)

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.

Farley Santos Ribeiro

2010-06-01

26

Grinding energy and physical properties of chopped and hammer-milled barley, wheat, oat, and canola straws  

Energy Technology Data Exchange (ETDEWEB)

In the present study, specific energy for grinding and physical properties of wheat, canola, oat and barley straw grinds were investigated. The initial moisture content of the straw was about 0.13–0.15 (fraction total mass basis). Particle size reduction experiments were conducted in two stages: (1) a chopper without a screen, and (2) a hammer mill using three screen sizes (19.05, 25.4, and 31.75 mm). The lowest grinding energy (1.96 and 2.91 kWh t-1) was recorded for canola straw using a chopper and hammer mill with 19.05-mm screen size, whereas the highest (3.15 and 8.05 kWh t-1) was recorded for barley and oat straws. The physical properties (geometric mean particle diameter, bulk, tapped and particle density, and porosity) of the chopped and hammer-milled wheat, barley, canola, and oat straw grinds measured were in the range of 0.98–4.22 mm, 36–80 kg m-3, 49–119 kg m-3, 600–1220 kg m-3, and 0.9–0.96, respectively. The average mean particle diameter was highest for the chopped wheat straw (4.22-mm) and lowest for the canola grind (0.98-mm). The canola grinds produced using the hammer mill (19.05-mm screen size) had the highest bulk and tapped density of about 80 and 119 kg m-3; whereas, the wheat and oat grinds had the lowest of about 58 and 88–90 kg m-3. The results indicate that the bulk and tapped densities are inversely proportional to the particle size of the grinds. The flow properties of the grinds calculated are better for chopped straws compared to hammer milled using smaller screen size (19.05 mm).

J.S. Tumuluru; L.G. Tabil; Y. Song; K.L. Iroba; V. Meda

2014-01-01

27

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

28

Work Roll Materials For Hot Strip Milling and Casting Methods of Rolling Roll  

Directory of Open Access Journals (Sweden)

Full Text Available The selection of materials for rolling, which is one of the powerful manufacturing process and the influence of these materials on the roll properties is an important factor. Also, the use of suitable material and various manufacturing technologies affect these characteristics. To understand that which roll grade is needed for which application, the rolling conditions, the roll grades and their properties should be known. In this work the evolution of roll materials from classical materials up to recently developed materials are presented and bimetallic roll technologies are investigated. Furthermore, experimentally cast pearlitic and martensitic roll microstructures were examined. The influence of microstructural phases on the roll properties were analyzed with the results of mechanical and microstructural observations.

?adi KARAGÖZ

2009-03-01

29

Inprovement in rolling procedure and steel plates finishing on the rolling mill 2800  

International Nuclear Information System (INIS)

Technology directed towards the increase of metal output and quality of production in the process of rolling and finishing of steel plates on the rolling mill 2800 has been elaborated. The slab end deformation in vertical stand with angular gauge of 60 deg has been applied. Minimal uneven gauge is established by work roll contouring. Special cuts of optimal form on the surface of roller breaking-down stand are used for removal of mill scale together with hydrocleaning at increasing pressure. Methods of line slitting of sheet edges are analyzed. The sheets of all types of steel with the thickness up to 40 mm may be successfully cut in plastic state at 600-900 deg C

30

Development of rolling mill for rectangular orthodontic wires production  

OpenAIRE

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...

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

2007-01-01

31

Development of rolling mill for rectangular orthodontic wires production  

Directory of Open Access Journals (Sweden)

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.

G.E. Totten

2007-09-01

32

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

Science.gov (United States)

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.

Rashidi Dashtbayaz, Samira

33

Rolling mill optimization using an accurate and rapid new model for mill deflection and strip thickness profile  

Science.gov (United States)

This work presents improved technology for attaining high-quality rolled metal strip. The new technology is based on an innovative method to model both the static and dynamic characteristics of rolling mill deflection, and it applies equally to both cluster-type and non cluster-type rolling mill configurations. By effectively combining numerical Finite Element Analysis (FEA) with analytical solid mechanics, the devised approach delivers a rapid, accurate, flexible, high-fidelity model useful for optimizing many important rolling parameters. The associated static deflection model enables computation of the thickness profile and corresponding flatness of the rolled strip. Accurate methods of predicting the strip thickness profile and strip flatness are important in rolling mill design, rolling schedule set-up, control of mill flatness actuators, and optimization of ground roll profiles. The corresponding dynamic deflection model enables solution of the standard eigenvalue problem to determine natural frequencies and modes of vibration. The presented method for solving the roll-stack deflection problem offers several important advantages over traditional methods. In particular, it includes continuity of elastic foundations, non-iterative solution when using pre-determined elastic foundation moduli, continuous third-order displacement fields, simple stress-field determination, the ability to calculate dynamic characteristics, and a comparatively faster solution time. Consistent with the most advanced existing methods, the presented method accommodates loading conditions that represent roll crowning, roll bending, roll shifting, and roll crossing mechanisms. Validation of the static model is provided by comparing results and solution time with large-scale, commercial finite element simulations. In addition to examples with the common 4-high vertical stand rolling mill, application of the presented method to the most complex of rolling mill configurations is demonstrated with an optimization example involving the 20-high Sendzimir mill.

Malik, Arif Sultan

34

Physical metallurgy of a HSS material for hot rolling mill rolls  

OpenAIRE

High Speed Steel (HSS) cast rolls are used in front finishing stands of hot strip mills. Good wear resistance and hardness at high temperatures, are defining features of HSS. Many types of carbides are present in these alloys, each having different effect upon their final properties. As a result, nature, morphology and amount of these carbides are factors of important concern. Identification and characterisation of carbides were realised. MC, M2C, M7C3 carbides were found. Some relation...

Lecomte-beckers, Jacqueline; Tchoufang Tchuindjang, Je?ro?me; Pirard, Eric; Breyer, Jean-pierre

2002-01-01

35

Slip Line Field Solution for Second Pass in Lubricated 4-High Reversing Cold Rolling Sheet Mill  

OpenAIRE

The development of a possible slip line field (slf) for theoretical calculations of the deforming pressure (load) in a second pass of a lubricated cold rolling sheet mill and validation using values from an aluminium sheet rolling mill was done in this work. This will be relevant in the manufacturing industries providing an easy method for determining necessary applied rolling load. Experimental rolling was carried out to observe the shear lines in the deformation field. Construction of possi...

Oluwole, Oluleke O.; Olayinka Olaogun

2011-01-01

36

Modelling and control of a hot rolling mill  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english In this paper, a real application of optimal control of a hot rolling mill is presented. It is used the state space model formulation in the minimization of the strip thickness variations. It is presented the simulation results of the control model, which is compared with industrial real data from p [...] rocess controled by traditional techniques. The results of the simulations lead to a less output thickness variations compared with the real industrial data.

F. G., Rossomando; J., Denti Filho.

2006-07-01

37

Bayesian model mixing for cold rolling mills: Test results.  

Czech Academy of Sciences Publication Activity Database

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

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

38

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

OpenAIRE

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...

Krawczyk, J.; Pacyna, J.

2010-01-01

39

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

Directory of Open Access Journals (Sweden)

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

Amelia Amelia

2000-01-01

40

Optimization of a Heavy Continuous Rolling Mill System Via Simulation  

Directory of Open Access Journals (Sweden)

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.

Ali Azadeh

2006-01-01

41

Crush Grinding  

Energy Technology Data Exchange (ETDEWEB)

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.

T. Q. Nguyen

2005-04-01

42

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.

43

Reducing the number of size classes in a cumulative rates model used for process control of a grinding mill circuit  

OpenAIRE

The number of size classes in a cumulative rates model of a grinding mill circuit is reduced to determine the minimum number required to provide a reasonably accurate model of the circuit for process control. Each reduced size class set is used to create a non-linear cumulative rates model which is linearised to design a linear model predictive controller. The accuracy of a model is determined by the ability of the corresponding model predictive controller to control important pro...

Le Roux, Johan Derik; Craig, Ian K.

2013-01-01

44

Milling of rice grains. The degradation on three structural levels of starch in rice flour can be independently controlled during grinding.  

Science.gov (United States)

Whole polished rice grains were ground using cryogenic and hammer milling to understand the mechanisms of degradation of starch granule structure, whole (branched) molecular structure, and individual branches of the molecules during particle size reduction (grinding). Hammer milling caused greater degradation to starch granules than cryogenic milling when the grains were ground to a similar volume-median diameter. Molecular degradation of starch was not evident in the cryogenically milled flours, but it was observed in the hammer-milled flours with preferential cleavage of longer (amylose) branches. This can be attributed to the increased grain brittleness and fracturability at cryogenic temperatures, reducing the mechanical energy required to diminish the grain size and thus reducing the probability of chain scission. The results indicate, for the first time, that branching, whole molecule, and granule structures of starch can be independently altered by varying grinding conditions, such as grinding force and temperature. PMID:21384921

Tran, Thuy T B; Shelat, Kinnari J; Tang, Daniel; Li, Enpeng; Gilbert, Robert G; Hasjim, Jovin

2011-04-27

45

Slip Line Field Solution for Second Pass in Lubricated 4-High Reversing Cold Rolling Sheet Mill  

Directory of Open Access Journals (Sweden)

Full Text Available The development of a possible slip line field (slf for theoretical calculations of the deforming pressure (load in a second pass of a lubricated cold rolling sheet mill and validation using values from an aluminium sheet rolling mill was done in this work. This will be relevant in the manufacturing industries providing an easy method for determining necessary applied rolling load. Experimental rolling was carried out to observe the shear lines in the deformation field. Construction of possible slip line field model was developed adhering strictly to assumptions of rigid plastic model. Calculation of the deforming force/load was achieved using Hencky’s equation. Results showed that the load calculations for constructed slip line field using aluminium sheet rolling as an example tallied with values obtained from Tower Aluminium rolling mill. Slip line fields constructed for the second pass described adequately the rolling pressure in the cold rolling process, giving a valid solution of the exact load estimates on comparison with the industrial load values. Roll pressure along the arc of contact rose fairly linearly from the entrance to a maximum at the exit point. This work showed that slf for the first pass in a cold rolling mill cannot be used for subsequent passes; it requires construction of slfs for each pass in the cold rolling process.

Oluleke O. Oluwole

2011-12-01

46

Sequential supervisory control, modelling and simulation of a multipass experimental rolling mill  

International Nuclear Information System (INIS)

This paper presents a Grafcet Model to control a laboratory-scale rolling mill and describes the design of a hybrid modelling and simulation strategy, its implementation in the G2 Real-time Expert System, and its application to the rolling mill. The rolling mill with its process variables and datalogging system is described. Grafcet is briefly overviewed, together with the implementation of the model on the rolling mill. The hybrid model base for the mill is designed from a combination of Object-Orientation, Rule-based Programming, GRAFCET, Equations, and procedures. The strategy, implemented in the real-time expert system, G2, involves the concurrent execution of three simulators: a continuous simulator, a GRAFCET simulator, and a heuristic simulator. (author)

47

Drop deformation in two-roll mills considering wall effects  

Science.gov (United States)

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.

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

2015-01-01

48

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.

49

Predictive 3D roll grinding method for reducing paper quality variations in coating machines  

OpenAIRE

The predominant trend in paper machines is towards an increased running speed. At the same time, the paper produced must have a higher and more even quality. In printing papers the main end-use properties and quality components are runnability, printability, and print quality. These coexistent requirements create new demands for the behaviour of rolls under production conditions. High quality printing paper grades are coated. In blade coating the thickness of the coating film on the paper sur...

Kuosmanen, Petri

2004-01-01

50

PVD Coated Mill Rolls for Cold Rolling of Stainless Steel Strips: Tribological and Mechanical Laboratory Tests  

OpenAIRE

The cost of rolling is determined in particular by productivity (i.e. reduction per pass and speed) and lifetime of rolls before regrinding. Adhesive wear of the sheet gives rise to transfer on the roll surface (called "roll-coating" or "pick-up"). Its occurrence depends on rolling conditions (load, speed, temperature, lubrication) and is one of the determining factors of the maximal reduction for a given rolling speed. Abrasive wear of the roll is the second factor for roll lifetime. Both ph...

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

2012-01-01

51

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.

52

Rolling of nickel base hardly deformable alloys in four-roller mills  

International Nuclear Information System (INIS)

Results are presented of the optimization procedure relating to a new rod rolling technology in the case of hard-to-deform nickel alloys of the type EhP220VD and some others on four-high mills. The rods 22, 16 and 12 mm in diameter being rolled on the mills MK-165 and MK-200 show an adequate surface quality, high mechanical and heat-resistance properties. The main principles of the rolling technology as applied to the treatment of hard-to-deform nickel alloys developed

53

Novel ultra-cryo milling and co-grinding technique in liquid nitrogen to produce dissolution-enhanced nanoparticles for poorly water-soluble drugs.  

Science.gov (United States)

A novel ultra-cryo milling micronization technique for pharmaceutical powders using liquid nitrogen (LN2 milling) was used to grind phenytoin, a poorly water-soluble drug, to improve its dissolution rate. LN2 milling produced particles that were much finer and more uniform in size and shape than particles produced by jet milling. However, the dissolution rate of LN2-milled phenytoin was the same as that of unground phenytoin due to agglomeration of the submicron particles. To overcome this, phenytoin was co-ground with polyvinylpyrrolidone (PVP). The dissolution rate of co-ground phenytoin was much higher than that of original phenytoin, single-ground phenytoin, a physical mixture of phenytoin and PVP, or jet-milled phenytoin. X-Ray diffraction showed that the crystalline state of mixtures co-ground by LN2 milling remained unchanged. The equivalent improvement in dissolution, whether phenytoin was co-ground or separately ground and then mixed with PVP, suggested that even when co-ground, the grinding of PVP and phenytoin occurs essentially independently. Mixing original PVP with ground phenytoin provided a slight improvement in dissolution, indicating that the particle size of PVP is important for improving dissolution. When mixed with ground phenytoin, PVP ground by LN2 milling aided the wettability and dispersion of phenytoin, enhancing utilization of the large surface area of ground phenytoin. Co-grinding phenytoin with other excipients such as Eudragit L100, hypromellose, hypromellose acetate-succinate, microcrystalline cellulose, hydroxypropylcellulose and carboxymethyl cellulose also improved the dissolution profile, indicating an ultra-cryo milling and co-grinding technique in liquid nitrogen has a broad applicability of the dissolution enhancement of phenytoin. PMID:22382412

Sugimoto, Shohei; Niwa, Toshiyuki; Nakanishi, Yasuo; Danjo, Kazumi

2012-01-01

54

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

Scientific Electronic Library Online (English)

Full Text Available 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 t [...] he 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 outstanding results. It is shown that the neural network based predictive control permits to overcome the existing time delays in the system dynamics. The proposed scheme implements a virtual thickness sensor, which releases an accurate estimate of the actual output thickness. It is shown that the dynamic response of the rolling mill system can be substantially improved by using the proposed controller. Simulation results are presented to illustrate the controller performance.

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

2003-03-01

55

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 outstanding results. It is shown that the neural network based predictive control permits to overcome the existing time delays in the system dynamics. The proposed scheme implements a virtual thickness sensor, which releases an accurate estimate of the actual output thickness. It is shown that the dynamic response of the rolling mill system can be substantially improved by using the proposed controller. Simulation results are presented to illustrate the controller performance.

J. M. Gálvez

2003-03-01

56

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

OpenAIRE

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...

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

2003-01-01

57

The effect of ZrO2 grinding media on the attrition milling of FeAl with Y2O3  

International Nuclear Information System (INIS)

Attrition milling of water and gas atomized FeAl was carried out with Y2O3, where ZrO2 was used as a grinding media in place of stainless steel balls to avoid contamination with Cr and C. Consolidation of the milled powders produced complex FeAl phases containing Zr which doubled the hardness and significantly improved the creep resistance as compared to that of unmilled and consolidated FeAl

58

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

59

Research upon the quality assurance of the rolling-mill rolls and the variation boundaries of the chemical composition  

Directory of Open Access Journals (Sweden)

Full Text Available The cast-iron rolls must present higher hardness at the rolling surface and lower in the core and the necks, adequate with mechanical resistance and in the high work temperature. If in the zone of the rolling surface, the hardness is guarantied by the irons structure, through the cementite quantities, the core of rolls must contain graphite, to assure this property. Starting from the lamination equipments aspects, from the form of rolls, of the technological interest zones and the structure, which assures the exploitation property, it was establish, through modeling, to the mathematical description of a direct influences, and in final, through successive determinations, to an optimum. One of the parameters, which are determined the structure of the irons destined for rolls casting, is the chemical composition, which guaranties the exploitation properties of the each roll in the stand of rolling mill. The realization of optimum chemical compositions of the cast-iron can constitute a technical efficient way to assure the exploitation properties, the material from which the rolling mills rolls are manufactured having an important role in this sense. Although the manufacture of rolls is in continuously perfecting, the requirements for superior quality rolls are not yet completely satisfied, in many cases, the absence of quality rolls preventing the realization of quality laminates or the realization of productivities of which rolling mills are capable. This paper presents an analysis of the main alloying elements from chemical composition, the influences upon the mechanical properties of the cast-iron rolls, and presents also some graphical addenda. Using the Matlab calculation and graphical programs we determinate some correlations between the hardness (on the working surface and on necks and the chemical composition. Using the double and triple correlations is really helpful in the foundry practice, as it allows us to determine variation boundaries for the chemical composition, in view the obtaining the desired and optimal values of the hardness of this very important metallurgical equipments. The enunciation of some mathematically modeling results, described through a number of multi-component equations determined for the spaces with 3 the and 4 dimensions, as well as the generation of some regression surfaces, of some curves of levels and volumes of variation, can be represented and interpreted by technologists and can be considerate diagrams of correlation between the analyzed variables. From this point of view the research is inscribes in context of scientific capitalization of the process and the industrial technologies optimizations, on the way of the analysis and the mathematical experiment.

Los cilindros o rodillos de laminación de función deben presentar una dureza más alta en su superficie y menor en el núcleo y el cuello del cilindro, adecuados a la resistencia mecánica y a la alta temperatura de trabajo. Si en la zona de la superficie de rodillo, la dureza se garantiza por las cementita existente en la estructura, el núcleo del cilindro debe tener grafito para asegurar la característica deseada. A partir de consideraciones sobre los equipos de la laminación, forma de los cilindros de laminación, zonas tecnológicas del interés y de la estructura, que asegura la característica de la explotación, se estableció un modelo que da una descripción matemática de las influencias directas y, finalmente, mediante determinaciones sucesivas, permite establecer un óptimo. Uno de los parámetros, que determinan la estructura del material de los cilindros de laminación es su composición química, que garantiza las características de la explotación de cada cilindro en el laminador. El empleo de las composiciones químicas de colada, óptimas, puede ser una manera técnicamente eficiente de asegurar las características de la explotación; el material de fabricación de los cilindros juega un papel importante. Aunque la fabricación de cilindros es objeto de una mejora c

Kiss, I.

2008-08-01

60

Rapid coal analysis. Part I: Particle size effects in slurry methods based on flame AA and swing-mill grinding  

Energy Technology Data Exchange (ETDEWEB)

Laser diffraction particle size measurements are used to study aerodynamic mass transport losses of a finely ground aqueous coal slurry aerosol in the spray chamber of a conventional atomic absorption spectrometer. A swing mill used to grind the coal produces many particles small enough to transport efficiently in the aerosol stream, but some are too large and can settle out in the spray chamber. This effect is reduced but not eliminated if one passes the grindings through a 325-mesh sieve prior to weighing and direct analysis. In spite of the partial ''leveling effect'' produced by the sieve, the residual mass transport loss in the spray chamber for direct coal slurry analysis by flame AA is about 51% (relative to aqueous standard transport). This accounts for part of the five-fold decrease in absorbance previously reported for finely ground coal slurries as compared with aqueous solutions. The remainder of the decrease is due to incomplete combustion and vaporization of coal particles in the nitrous-oxide/ acetylene flame.

Mohamed, N.; McCurdy, D.L.; Wichman, M.D.; Fry, R.C.; O' Reilly, J.E.

1985-11-01

61

Rolling process simulation of a pair-crossed hot strip mill  

International Nuclear Information System (INIS)

Process simulation can help optimize the operating parameters aiming to improve the quality of rolled products. In this paper, software in Visual Basic language is developed to simulate the hot rolling process of a pair-crossed mill. The strip temperature is calculated by considering air cooling, water cooling, heat generation and conduction.The production parameters including rolling speeds, resistance to deformation, rolling forces, drive torques and powers are evaluated by mathematical models and their parameter identification support tools. The deformation of roll stack is calculated by influential function method. The roll temperature and expansion are calculated by finite differential method, and the roll wear is described by empirical formula. Based on these calculations as well as the effect of heredity is taken into account, the strip crown and flatness then can be obtained. The results show that the simulation software has friendly user interface, high accuracy and practicability. It can be served as a basis for the mill design and optimization of process parameters to acquire high quality of hot rolled strip. (author)

62

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

63

Production of sponge iron powder by reduction of rolling mill scale  

OpenAIRE

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...

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

2012-01-01

64

Optimization of cold rolling procedure using reversing mill  

International Nuclear Information System (INIS)

Optimum procedures of the band cold rolling of the 12Kh18N9T steel and 7KhNM alloy are calculated according to the developed algorithm. Results of calculations of optimum procedures of rolling are given. It is shown that realization of optimum procedure will permit to produce a plotting band with minimum cross section different-thickness at simultaneous reduction of a number of gaps

65

Coupled dynamic modeling of rolls model and metal model for four high mill based on strip crown control  

Science.gov (United States)

The crown is a key quality index of strip and plate, the rolling mill system is a complex nonlinear system, the strip qualities are directly affected by the dynamic characteristics of the rolling mil. At present, the studies about the dynamic modeling of the rolling mill system mainly focus on the dynamic simulation for the strip thickness control system, the dynamic characteristics of the strip along the width direction and that of the rolls along axial direction are not considered. In order to study the dynamic changes of strip crown in the rolling process, the dynamic simulation model based on strip crown control is established. The work roll and backup roll are considered as elastic continuous bodies and the work roll and backup roll are joined by a Winkler elastic layer. The rolls are considered as double freely supported beams. The change rate of roll gap is taken into consideration in the metal deformation, based on the principle of dynamic conservation of material flow, the two dimensional dynamic model of metal is established. The model of metal deformation provides exciting force for the rolls dynamic model, and the rolls dynamic model and metal deformation model couple together. Then, based on the two models, the dynamic model of rolling mill system based on strip crown control is established. The Newmark-? method is used to solve the problem, and the dynamic changes of these parameters are obtained as follows: (1) The bending of work roll and backup roll changes with time; (2) The strip crown changes with time; (3) The distribution of rolling force changes with time. Take some cold tandem rolling mill as subject investigated, simulation results and the comparisons with experimental results show that the dynamic model built is rational and correct. The proposed research provides effective theory for optimization of device and technological parameters and development of new technology, plays an important role to improve the strip control precision and strip shape quality.

Sun, Jianliang; Peng, Yan; Liu, Hongmin

2013-01-01

66

Soft Starting Arrangements Availables for Hot Rolling Mills for Energy Conservation  

Science.gov (United States)

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.

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

2012-07-01

67

Identification of Material Properties Based on Rolling Process at 4-Stand Laboratory Mill  

Science.gov (United States)

The general objective of the work is to estimate the properties of the material in hot strip rolling process. The authors propose a modified inverse algorithm; to make direct use of the manufacturing process instead of conventional plastometric tests. This approach allows to reduce time and costs of identification. The rolling at 4-stand pilot mill at the Institute of Metal Forming, TU Bergakademie, Freiberg was selected. The material was C45 steel. The measured quantities of the process were rolling loads and torques, as well as temperatures. Numerical tests have shown that accuracy of torque predictions is low, therefore, the goal function of inverse analysis was defined as an average square root error between measured and FEM calculated rolling loads only. The first stage of the work was to develop the model of the hot strip rolling, which defines the direct model in the inverse analysis. This model is complex, it composes the whole roughing and finishing rolling. Based on the model and results of the laboratory experiment, the deformation process including the temperature field and the recrystallization up to the last finishing mill is calculated. Moreover, an application of the inverse analysis to the identification of the models of the hot strip rolling and design of the rolling parameters allows to obtain the required microstructure of final products. Inverse analysis and/or optimization of such a manufacturing chain is time-consuming. Large number of control parameters makes the time of the analysis unacceptable. Therefore, the metamodel of the hot rolling is applied to make the inverse calculations efficient. In the work the results of calculations with identified process parameters and experimental data are compared and presented. Also advantages and disadvantages are described.

Szeliga, D.; Graf, M.; Kawalla, R.; Pietrzyk, M.

2011-05-01

68

Evaluation of the fatigue damage of rolls for strip mills below the surface by x-ray diffraction method  

International Nuclear Information System (INIS)

Technique of the X-ray diffraction line profile analysis has been applied to the study of fatigue damage below the surface of the work and the backup rolls of cold strip mill and the backup rolls of hot strip mill. Half value breadth has been taken as a measure of fatiguing. Fatigued zone below the surface of rolls is well correlated with the half contact length of roll, L; 0.03 L in the work roll of cold strip mill and 0.1 L in the other rolls. Changes in the half value breadth with increase in cycles of roll contact differ in accordance with the surface hardness of the rolls: continued cycling results in decrease of the half value breadth at surface in hard rolls (H sub(s) >= 60) and increase in soft rolls (H sub(s) <= 50). The technique of X-ray study of fatigue can be extended to prediction and prevention of accidental failure of rolls due to fatigue fracture such as spalling. Furthermore the amount of surface dressing at regular maintenance of rolls can be saved significantly on the basis of accurate evaluation of the depth of fatigue damaged zone. (author)

69

Kinetic study of the removal of Cu(II) from aqueous solutions by rolling mill scale  

International Nuclear Information System (INIS)

The removal of Cu(II) from aqueous solutions by rolling mil scale occurs through a process of oxidation-reduction or cementation of Cu''2+ ions in aqueous solution onto metallic iron (Fe''0) contained in the mill scale. The kinetics of cementation of copper onto iron was evaluated over different temperatures, initial copper concentrations and solid/liquid relations. Process of copper removal by rolling mill scale obeys a first-order kinetic law. The rate constant value (k) varies with temperature and initial cation concentration in solution at low temperatures. At high temperatures the value of k remains practically constant. the solid/liquid relation value affects the rate constant value too. (Author) 19 refs

70

A Simple Method of Designing Dual loop Controller for Cold Rolling Mill  

OpenAIRE

The mathematical model (Interval Plant) of the web guide in rolling mill is controlled using PID controller. The given interval plant is approximated to first order plus time delay with integrator (FOPTDI) system. The dual loop control (DLC) method proposed by Jacob and chidambaram for design PID controllers is extended for FOPTD+I systems. The performance of the closed loop system is evaluated for both the original and the approximated model. The controllers are also tuned using Internal Mod...

S. Umamaheswari,; V.Palanisamy,; Chidambaram, M.

2010-01-01

71

A nucleonic thickness control system for a thin sheet rolling mills machine  

International Nuclear Information System (INIS)

A nuclear transmission thickness gauge and control system was developed. It was used to improve the thickness control of the thin sheet metal production in the cold rolling mills. The deviation from the nominal thickness of the sheet metal was reduced through automatic correction in continuous production process. The five main parts of the nuclear thickness gauge are : radiation source. radiation detection system, analog to digital converter, micro controller and interfaces. A thickness gauge with Am-241 of 3.7 x 109 Bq as radiation source together with a 1 x 1 inch NaI(T 1) as radiation detector was installed on an old version cold rolling mills producing brass sheets of various thickness from 0.1 to 0.5 mm with a feeding speed of 25 m/min. It was found that with nuclear thickness gauge the brass sheet thickness could be controlled with a deviation of ±0.01 mm in comparison with ±0.02 mm resulting from the previous conventional thickness control. Thus, the performance of the old version cold rolling mills can be improved through the development of an automatic nuclear electronic thickness gauging

72

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

Energy Technology Data Exchange (ETDEWEB)

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 Cr{sub 2}Nb 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.

Shukla, A.K.; Narayana Murty, S.V.S.; Suresh Kumar, R. [Materials and Metallurgy Group, Vikram Sarabhai Space Centre, Trivandrum 695 022 (India); Mondal, K., E-mail: kallol@iitk.ac.in [Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

2013-12-15

73

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

74

Simulation of the thermal conditions of rolls in a wide-strip hot-rolling mill to determine their effective cooling conditions  

Science.gov (United States)

An advanced procedure is developed for the thermal calculation of the rolls in a wide-strip hot-rolling mill (WSHRM). It combines the following two adaptive models: the thermal balance in the active surface layer in a roll per revolution and the thermal balance in the main zones of work and backup rolls with axisymmetric temperature fields with allowance for the heat exchange between a strip, rolls, the coolant, and the environment. In contrast to the well-known models, this advanced procedure calculates the bulk mean temperature and the thermal profile in a roll more accurately, since the temperature drop across the surface layer in this procedure is calculated allowing for the intensities of the contact and convective heat exchange between rolls. Data on the coefficient of heat transfer from rolls to the coolant supplied at an excess pressure of 1.0-1.5 MPa are presented for the first time. This procedure is used in a 2000 WSHRM and improves the transverse profile of hot-rolled strips due to a stabilized thermal profile in rolls.

Garber, E. A.; Khlopotin, M. V.; Traino, A. I.; Popov, E. S.; Savinykh, A. F.

2009-06-01

75

The grinding characteristics of the metal components in Printed Circuit Boards(PCBs) scrap by the swing-hammer type impact mill  

Energy Technology Data Exchange (ETDEWEB)

A study on the grinding characteristics of metal components in printed circuit boards (PCBs) scrap by a swing-hammer type impact mill was conducted. The PCBs scrap crushed to sizes less than 3 mm were pulverized to liberate metal components by the impact mill. The effect of rotation speed of hammer on the grinding characteristics was investigated. The particle size distribution and degree of liberation of metals such as copper and solder were measured. The effect of rotation speed and particle size on the shape sorting of metal particles from milled PCBs was investigated using an inclined vibrating plate. At the hammer speed of 61.3 m/s about 80% of the copper particles became larger than 297 {mu}m while 90% of solder particles was smaller than 297 {mu}m. In the shape sorting method, the recovery location becomes shorter as the rotation speed of hammer increases. The recovery location for particles larger than 297 {mu}m was shorter than for particles sized between 149 and 297 {mu}m. As the recovery location becomes shorter, KI value increases towards unity while {phi}{sub c} value decreases towards unity indicating the more roundness of mental particles. (author). 17 refs., 7 figs.

Lee, Jae-Chun; Kil, Dae-Sup; Nam, Chul-Woo [Korea Institute of Geoscience and Mineral Resources, Taejeon(Korea); Choi, Joon-Chul [Korea Computer Recycling Co., Hwasung(Korea)

2002-04-30

76

Plate Rolling Modeling at Mill 5000 of OJSC ``Magnitogorsk Iron and Steel'' for Analysis and Optimization of Temperature Rates  

Science.gov (United States)

Modeling of strip deflected mode and thermal state in rolling is an integral part of the technology and perspective rolling-mill machinery such as plate mill 5000 of the OJSC "Magnitogorsk Iron and Steel". To comprehend metal behavior in the deformation zone in the rough passes during plate rolling it is essential to assess the impact of various temperature factors on variations in field of stress and strain intensities as well as temperature fields in deformation. To do such researches in consideration of various software products and adequate results one of the most effective methods nowadays is regarded as the method of finite elements. The research shows modeling of roughing rolling of a pipe steel sheet with strength category X80 according to standard API-5L. In the research of the metal deflected mode software product DEFORM 2D has been used for the isothermal and nonisothermic process. The mathematical modeling allows revealing the impact of temperature field on the metal deflected mode in the rough passes in plate rolling. Supposedly, it is deformation heating that can have more impact on the ingot temperature profile in the finishing passes in controlled rolling of the pipe steel grades. It is defined by high percent reduction, rolling speeds; more area of heat exchange surface; less thickness and lower temperature of rolling. The results can be used to develop efficient modes of plate rolling of the pipe steels.

Salganik, V.; Shmakov, A.; Pesin, A.; Pustovoytov, D.

2010-06-01

77

INTERACTION EFFECTS OF FIVE MILLING VARIABLES ON DURUM WHEAT IN THE FIRST BREAK SYSTEM  

Science.gov (United States)

Interactions among five major milling variables (flute angle, number of corrugations, flute orientation, speed differential of the grinding rolls, and wheat moisture) were investigated from the "First Break" products of a pilot-scale durum mill. A complete factorial design was arranged for statisti...

78

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

79

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)

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.

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

2011-02-15

80

The technology of production of high-strength, cold resistant weldable steel on wide-strip rolling mill  

International Nuclear Information System (INIS)

Regularities of influence of technological rolling parameters on wide-strip rolling mill on structure and mechanical characteristics of low-carbon steel of St3sp type were established. Possibility of sufficient growth of strength and cold resistance of strips, produced by hot working, as compared to traditional technology is shown. This is achieved by grain refinement and formation of subgrain structure in ferrite

81

Steel balls forming by cross rolling with upsetting  

Directory of Open Access Journals (Sweden)

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.

Z. Pater

2013-01-01

82

Feasibility of TiBN PVD Coating for Mill Rolls - Laboratory Testing of Anti-adhesive and Fatigue Resistance Properties  

OpenAIRE

The ceramic coatings deposited by Physical Vapour Deposition (PVD) are known for their high hardness. They offer a wide variety of friction coefficients. They have been used for a number of years for the coating of cutting tools; they have shown high efficiency in this field. Considering this, some of these coatings might prove efficient in the field of metal rolling. Yet to the best of the authors' knowledge, they have never been used industrially for rolling mill rolls. TiBN is one of the P...

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

2011-01-01

83

Steel grinding media in production use  

International Nuclear Information System (INIS)

This paper reviews the types of steel being used for grinding rods and balls by the mining industry in U. S. and Canada. Results of a Dec. 1973 grinding media survey of U. S. and Canadian mills are summarized. Common alloying elements (C, Mn, Cr, Mo, Cu, etc.) are discussed. Grinding balls and rods are discussed separately; wear tests using irradiated balls are described. Finally, defects in grinding media are discussed

84

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

85

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

OpenAIRE

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 deforma...

Nilsson, Maria; Olsson, Mikael

2012-01-01

86

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

Science.gov (United States)

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

Thangavel, S; Palanisamy, V; Duraiswamy, K

2008-04-01

87

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)

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.

Behzad BahramiNejad

2015-03-01

88

MOLIENDA DE CLINKER DE CEMENTO: EVALUACIÓN DE LA INFLUENCIA DE LA VELOCIDAD DE GIRO DEL MOLINO, EL TIEMPO DE RESIDENCIA Y LA CARGA DE LOS MEDIOS DE MOLIENDA / CEMENT CLINKER GRINDING: EVALUATION OF MILL SPIN SPEED, RESIDENCE TIME AND GRINDING MEDIA LOAD  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish se evaluó la molienda de clinker en molino de bolas, variando: velocidad del molino (24 y 72 RPM), tiempo de residencia (3 y 5 horas) y carga de cuerpos moledores (30 y 40 %), mediante un modelo factorial, el objetivo fue evaluar la incidencia de estos sobre el porcentaje másico pasante 45 micras y [...] el área superficial, factores determinantes en la calidad del cemento comercial. Se determinaron propiedades fisicoquímicas, de composición, naturaleza mineralógica y distribución granulométrica del material empleando Fluorescencia de Rayos X, Análisis de Área Superficial y Análisis Granulométrico por Tamizado. Se encontró que la cantidad de masa pasante de 45 micras crece al aumentar la velocidad del molino y en menor proporción al incrementar el tiempo, y que el cambio de carga de cuerpos moledores resulta insignificante. El área superficial aumenta al incrementarse velocidad, tiempo y carga; no obstante estos últimos en proporción menor que con la velocidad. Abstract in english In this study, the milling of clinker was evaluated by varying the mill speed (24 and 72 RPM), residence time (3 and 5 hours) and grinding media load (30 and 40 %) in a ball mill. The experiment was designed as a three level factorial statistical model. The main objective was to assess the effect of [...] these parameters on cumulative passing percentage (CPP) and surface area, both of which affect the quality of commercial cement. Physico-chemical properties, composition, mineralogy and granulometric distribution were determined using X Ray Fluorescence, Surface Area Analysis and Sieving Granulometric Analysis. Results showed that that CPP through a 325 mesh increases considerably with mill spin speed, that the rate of CPP increase decreases with residence time and that grinding media load changes were not significant. The surface area increased mainly as a function of increases in mill spin speed, while residence time and grinding media load had lesser impacts.

ADRIANA, OSORIO; GLORIA, RESTREPO; JUAN, MARÍN.

2009-06-01

89

Alteration of sepiolite by dry grinding  

OpenAIRE

The study of the grinding effects on clay minerals is a subject of great interest because is a very common process in the industry and research laboratory. Very little is known of the effects of dry grinding on sepiolite, which is widely used in the industry. In this study, Vallecas sepiolite was subjected to dry grinding in a ball mill for various periods of time. Changes induced during the comminution process were examined by X-ray powder diffraction (XRD), specific surfac...

Cornejo, J.; Hermosin, M. C.

1987-01-01

90

Transverse Crack Modeling of Continuously Casted Slabs through Finite Element Method in Roughing Rolling at Wide Strip Mill  

Science.gov (United States)

In the pipe billet production at the wide strip mills of hot rolling big metal losses are caused by surface defects that affect most parts of the finished strips. The rolling surface defects are referred to the breach of steelmaking technology. Specialists mostly face defects of metal surface such as "scab" and "crack". The only area suffered from these defects is a slab edge. This area has the least surface temperature at the unbending of the continuous-casting machine, and together with deep buckles made by reciprocating motion of the crystallizer it is mostly subjected to transverse cracks that can be up to several millimeters. Each surface defect of the continuously casted slab will further turn into the surface defect of the strip bar. For some grade sets, mostly made of pipe steel grades the amount of strips with these defects can reach up to 60-70%. The area that is mostly prone to these defects is the edge of the strip. The work reveals investigation of the form change peculiarities in the transverse cracks of the continuously casted slab in roughing rolling in the horizontal rollers. The finite element method with software DEFORM 3D V6.1 has been applied in modeling. The work gives a form change mechanism of transverse cracks of slabs in deformation. Further crack growth in rolling is assessed due to Cockroft-Latham criteria.

Pesin, A.; Salganik, V.; Pustovoytov, D.

2010-06-01

91

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

92

Catalytic surface modification of roll-milled poly({epsilon}-caprolactone) biaxially stretched to ultra-thin dimension  

Energy Technology Data Exchange (ETDEWEB)

A novel roll-milling polymer processing technique along with biaxial stretching was used to fabricate 10 {mu}m thick poly({epsilon}-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 {sup o}C. 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.

Foo, H.L. [Graduate Programme in Bioengineering, National University of Singapore (Singapore); Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Taniguchi, A. [Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Yu, H. [Graduate Programme in Bioengineering, National University of Singapore (Singapore); Department of Physiology, National University of Singapore (Singapore); Okano, T. [Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Institute of Biomedical Engineering, Tokyo Women' s Medical University (Japan); Teoh, S.H. [Graduate Programme in Bioengineering, National University of Singapore (Singapore) and Department of Mechanical Engineering, National University of Singapore (Singapore)]. E-mail: mpetsh@nus.edu.sg

2007-03-15

93

The ways of increasing the socket accuracy in the course of broaching on a three-roll mill  

International Nuclear Information System (INIS)

The results are presented of experimental investigations on the wall thickness variation of sleeves broached on a three-high mill with barrel-shaped rolls. To obtain sleeves with relatively accurate geometrical dimensions it is necessary to ensure a high rigidity of alignment of the sleeve-mandrel-rod system with a 3- to 4-fold safety margin for rod resistance to longitudinal bending with a length equal to that of the sleeve. Broaching is better to accomplish at increased feed angles (14-16 deg.) with partial cooling of the billets

94

New rolling strategy for heavy plate mills. Development and installation; Nouvelle strategie de laminage pour toleries fortes. Developpement et implantation  

Energy Technology Data Exchange (ETDEWEB)

For the last few years, an evolution has been noted in the Usinor Sacilor plate mill order book going towards thinner, harder and wider products, causing a malfunction of the control system (PLATE). This problem could be solved by the development of a new strategy making it possible to exceed the flatness tolerances during the main thickness reduction phase. Installation of this new strategy in the CLI PLATE control system made it possible to increase the final temperature of the product (- 100 deg. C), to decrease the number of schema passes (up to 50 %) and thus to extend automatic rolling to finer products while guaranteeing a good final flatness. (authors)

Irastorza, L.; Dreistadt, D. [Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France); Lavolaine, P.; Dumoulin, P.; Martin, D.; Medalle, G. [Societe Creusot-Loire, 75 - Paris (France)

1996-07-01

95

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)

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.

Laerte José Fernandes

2012-01-01

96

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

97

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

OpenAIRE

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 thr...

GHEORGHE VOICU; GABRIEL-ALEXANDRU CONSTANTIN; ELENA-MADALINA STEFAN; PAULA VOICU

2013-01-01

98

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.)

99

Energy Use of Fine Grinding in Mineral Processing  

Science.gov (United States)

Fine grinding, to P80 sizes as low as 7 ?m, is becoming increasingly important as mines treat ores with smaller liberation sizes. This grinding is typically done using stirred mills such as the Isamill or Stirred Media Detritor. While fine grinding consumes less energy than primary grinding, it can still account for a substantial part of a mill's energy budget. Overall energy use and media use are strongly related to stress intensity, as well as to media size and quality. Optimization of grinding media size and quality, as well as of other operational factors, can reduce energy use by a factor of two or more. The stirred mills used to perform fine grinding have additional process benefits, such as polishing the mineral surface, which can enhance recovery.

de Bakker, Jan

2013-12-01

100

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)

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.

K. Laber

2015-04-01

101

Strip thickness estimation in rolling mills from electrical variables in AC drives  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english The large-scale utilization of steel in the modern society highlights the importance of the lamination process, and poses new demands for advanced technologies in the electromechanical equipments as well as for the control systems. Several process parameters, such as strip thickness, friction, tensi [...] on, temperature, and rolling speed have a strong influence in the quality of the final product, and strategic importance in the control system. This paper introduces a method to obtain the torque and rolling mechanical power estimates in real time, without utilization of lamination process models. In contrast to existing techniques, in this work these estimates are derived from stator electrical variables, readily available in AC drives. This work also discusses the utilization of the torque and rolling mechanical power estimates to determine input and output strip thickness, by means of a neural network. Simulation results are presented and compared to real industrial data to demonstrate the validity of the proposed technique.

N.S., Marcellos; J.F., Denti; G.C.D., Sousa.

2009-12-01

102

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

OpenAIRE

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 in...

Jeetendra Mohan Khare, Sandip Kumar Mishra

2013-01-01

103

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

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...

Tchuindjang, Je?ro?me Tchoufack; Lecomte-beckers, Jacqueline

2010-01-01

104

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  

OpenAIRE

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-se...

Rafiei Masoud; Gadgil Alaka; Ghole Vikram; Gore Sharad; Jaafarzadeh Neemat; Mirkazemi Roksana

2009-01-01

105

Effect of the microstructure on tribological phenomena occurring on the surface of a mill roll made of SA5T cast iron (GJSL-HV600 - GJSL-330NiMoCr12-8-3)  

OpenAIRE

This paper deals with the role of the microstructure in the tribological wear processes occurring in a cast iron mill roll. For this purpose, a piece of a broken roll, made in Italy, was collected. Its microstructure consisted of modular graphite, transformed ledeburite and a matrix composed of bainite and martensite. Metallographic investigations were performed on the roll working surface in conjunction with metallographic tests effected within its surface layer. There was established the re...

Krawczyk, J.

2008-01-01

106

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)

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.

Fenglan Wang

2013-06-01

107

STABLE DIAMOND GRINDING  

OpenAIRE

The paper generalizes on the one hand theory of kinematic-geometrical simulation of grinding processes by means of tools with working part as binding matrix with abrasive grains located in it in random manner, for example diamond grains, and on the other hand practical performance of combined grinding process, based on introduction of additional energy as electric discharges and called by the organization-developer (Kharkov Polytechnic Institute) «diamond-spark grinding» as applied to proc...

Yury Gutsalenko

2010-01-01

108

STUDIES ON CONTINUOUS GRINDING PROCESS FOR DRIED WATER CHESTNUT KERNEL  

Directory of Open Access Journals (Sweden)

Full Text Available Grinding is a unit operation to break big solid material into smaller pieces. As far as process of grinding is concerned, power consumption, specific energy consumption and particle size distribution and mill capacity are main considerations from engineering point of view. The experiments were conducted to study the effect of speed of mill, sieve size, feed rate and time of grinding on power consumption and average particle diameter of water chestnut in continuous grinding process. Power consumption was measured for a constant feed rate of 1 and 2 kg/h at different speed of the mill varied from 800 to 1200 rpm for the sieve openings of 0.5 mm, 1.0 mm and 2.0 mm. For all the sieve sizes and feed rates, it was observed that as the speed of the mill increases, there is an increase in power consumption and found significantly low for higher sieve size and lower feed rate. The size distribution of the water chestnut kernel for different speeds and sieve sizes at constant feed rate were obtained by sieve analysis. The milling speed has no significant effect on particle size distribution of ground product and mass fraction was minimum at lower feed rate and higher sieve size. Harris model was found best suitable to describe the size distribution in continuous grinding process. Fineness modulus decreases with increase of milling speed for experimental sieve size and feed rate.

S.K. GARG

2010-06-01

109

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)

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.

Yi-Wen Cheng; Patrick Purtscher

1999-07-30

110

Coal grinding options in pyroprocessing operations  

Energy Technology Data Exchange (ETDEWEB)

Solid fuels can be used as an alternative to oil and gas in ore dryers, fluid bed roasters and rotary kilns. This paper discussed issues related to the storage, handling, pulverization and firing of coal and petroleum cokes in mineral processing applications. Inert and non-inert grinding and firing systems were discussed. Coal grinding mills and configurations were reviewed along with issues related to deflagration prevention, containment and venting. Safety requirements for ignition sources were outlined together with various process instrumentation and control systems. It was concluded that pulverized fuel grinding and firing systems must be adequately engineered with applicable codes in order to ensure reliable and efficient operations. 1 ref., 3 tabs., 5 figs.

Hilchey, B.J.; Golebiowski, E.A. [Phoenix Process Engineering Inc., Saint Peters, MO (United States)

2009-07-01

111

Estudo de variabilidade e otimização do circuito de moagem SAG da Usina do Sossego Optimization of the Sossego SAG mill grinding circuit  

Directory of Open Access Journals (Sweden)

Full Text Available A Mina do Sossego, localizada na região sudeste do Estado do Pará, foi a primeira usina da Vale a operar um moinho SAG para processar minério de cobre e ouro. Nos primeiros três anos de operação, foram estudadas alternativas para aumento de produção, principalmente focadas em aspectos operacionais da moagem SAG. Em seguida, foram realizados estudos visando a identificar o desempenho do circuito em função dos diferentes tipos de minérios alimentados. Uma caracterização completa do minério foi realizada em conjunto com a calibração de modelos matemáticos baseados em amostragens conduzidas no circuito industrial. O simulador foi então usado para prever níveis de produção associados a cada tipo de minério, assim como determinar configurações otimizadas para o circuito. Esse artigo descreve em detalhes os principais aspectos da otimização do circuito, assim como o método para prever a produção em função das características do minério e do circuito.Sossego was the first Vale SAG mill operation to process copper-gold ore. It is located in the State of Para, southeastern Amazon region of Brazil. In the first three years of continuous operation, Vale investigated different alternatives for improving the circuit’s performance by investigating operating conditions, mainly focusing on the SAG mill. It was decided to further assess the performance of the comminution circuit as a function of ore characteristics. A comprehensive ore characterization program was then conducted, together with the calibration of mathematical models on the basis of surveys carried out at the industrial circuit. The simulator was then used to predict the throughput associated to each ore type, as well as to establish the optimized circuit configuration and tailored operating conditions. This paper describes in detail the main aspects of optimizing the industrial circuit performance, as well as the successful method for predicting the production as a function of ore characteristics and circuit configuration.

Maurício Bergerman

2009-03-01

112

Estudo de variabilidade e otimização do circuito de moagem SAG da Usina do Sossego / Optimization of the Sossego SAG mill grinding circuit  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A Mina do Sossego, localizada na região sudeste do Estado do Pará, foi a primeira usina da Vale a operar um moinho SAG para processar minério de cobre e ouro. Nos primeiros três anos de operação, foram estudadas alternativas para aumento de produção, principalmente focadas em aspectos operacionais d [...] a moagem SAG. Em seguida, foram realizados estudos visando a identificar o desempenho do circuito em função dos diferentes tipos de minérios alimentados. Uma caracterização completa do minério foi realizada em conjunto com a calibração de modelos matemáticos baseados em amostragens conduzidas no circuito industrial. O simulador foi então usado para prever níveis de produção associados a cada tipo de minério, assim como determinar configurações otimizadas para o circuito. Esse artigo descreve em detalhes os principais aspectos da otimização do circuito, assim como o método para prever a produção em função das características do minério e do circuito. Abstract in english Sossego was the first Vale SAG mill operation to process copper-gold ore. It is located in the State of Para, southeastern Amazon region of Brazil. In the first three years of continuous operation, Vale investigated different alternatives for improving the circuit’s performance by investigating oper [...] ating conditions, mainly focusing on the SAG mill. It was decided to further assess the performance of the comminution circuit as a function of ore characteristics. A comprehensive ore characterization program was then conducted, together with the calibration of mathematical models on the basis of surveys carried out at the industrial circuit. The simulator was then used to predict the throughput associated to each ore type, as well as to establish the optimized circuit configuration and tailored operating conditions. This paper describes in detail the main aspects of optimizing the industrial circuit performance, as well as the successful method for predicting the production as a function of ore characteristics and circuit configuration.

Maurício, Bergerman; Homero, Delboni; Marco, Nankran.

2009-03-01

113

Effects of grinding on certain crystalline structures  

International Nuclear Information System (INIS)

The effects of grinding on certain crystalline substances (ZnO, ZnS, Sb), have been studied using X-ray diffraction and electron microscopy. The treatments were carried out using a vibrating mill which involves a higher energy than more conventional equipment such as ball-mills. Various methods have been proposed for determining the width of the intrinsic profile (?). In the case of zinc oxide it has been shown possible to differentiate the respective contributions of the fragmentation effects and of lattice deformation effects to the overall effects of the grinding. For the two types of zinc sulfide (blend and Wurtzite) it has been shown that the blend-wurtzite) transition point is very much decreased, and that the rate of transformation of wurtzite into the stable form (blend) at room temperature is considerably increased by the grinding. In the case of antimony, the method of fragmentation shows the existence of an anisotropy which appears to be connected with easily cleavable planes. These observations show that in the case of grinding carried out with sufficient energy, the accumulation of this energy in the matter through the creation of lattice defects can accelerate the reaction rate or bring about physical transformations. (author)

114

The effects of grinding on the physicochemical characteristics of white sepiolite from Golesh  

Directory of Open Access Journals (Sweden)

Full Text Available The influence of grinding white sepiolites from the Magure-Golesh mine in Southern Serbia on their structure and on the rheological characteristics of their aqueous suspensions was investigated. Sepiolite samples of hard and soft consistency were ground in three different types of mills: a ball mill, air-stream mill, and a colloid mill. The effect of grinding on the sepiolite samples was investigated by SEM, XRD, IR, TG and BET methods and by chemical analysis. Grinding generally resulted in the separation of the sepiolite fibers, and partial amorphization. In addition, grinding produced substantial changes in the apparent viscosity and rheological characteristics of dilute aqueous suspensions of sepiolite. It is concluded that the viscosities are especially affected by the type of grinding employed.

MILAN MITROVIC

2002-03-01

115

Dry grinding with CBN wheels, the effect of structuring  

OpenAIRE

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...

Rabiey, Mohammad

2011-01-01

116

STABLE DIAMOND GRINDING  

Directory of Open Access Journals (Sweden)

Full Text Available The paper generalizes on the one hand theory of kinematic-geometrical simulation of grinding processes by means of tools with working part as binding matrix with abrasive grains located in it in random manner, for example diamond grains, and on the other hand practical performance of combined grinding process, based on introduction of additional energy as electric discharges and called by the organization-developer (Kharkov Polytechnic Institute «diamond-spark grinding» as applied to processing by means of diamond wheel. Implementation of diamond-spark grinding technologies on the basis of developed generalized theoretical approach allows to use the tool with prescribed tool-life, moreover to make the most efficient use of it up to full exhausting of tool-life, determined by diamond-bearing thickness. Development is directed forward computer-aided manufacturing.

Yury Gutsalenko

2010-06-01

117

Thermal characteristics of grinding fluids  

OpenAIRE

High Efficiency Deep Grinding (HEDG) combines high depths of cut, high grinding wheel speeds with high work piece feed rates to deliver a very high stock removal process that can produce components free of surface damage. High contact temperatures are a characteristic of the process and this produces a mass of hot grinding sparks being ejected from the grinding zone. Neat oil cutting fluids are typically used in HEDG due to their excellent lubricity, but the high grinding wh...

Massam, Mark

2008-01-01

118

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

119

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

Science.gov (United States)

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.

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

2015-02-01

120

Work index and grinding energy assessment of Dilband iron ore Pakistan  

International Nuclear Information System (INIS)

Importance of comminution in mineral processing sector is highly acknowledged from energy perspective. In present study an attempt was made to understand the commuting behavior of Dilband iron ore and to compute the grinding energy requirement for production of ultra fine particles up to mesh of liberation. In this regard standard grind ability tests developed by the Chair of Mineral Processing Leoben Austria was used for calculating work index of Dilband iron ore. The grinding tests were conducted in rod and ball mills. The work index value of two feed size fractions with 80% passing at 3800 macro m and 5200 macro m was noted to be 11.85 kwh/t and 9.3 kwh/ton respectively. Ball mill grinding test indicates that dry grinding in open circuit is not efficient and consumes more energy of 88.48kwh/t of ore for grinding 1000/40 macro to 80% <40 macro m size. (author)

121

Design of the Soymilk Mill based on TRIZ Theory  

OpenAIRE

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 D...

Jiang Fan; Wang Yijun; Xiang Jianhua; Huang Chunman

2013-01-01

122

The Influence of Ball Charge and Media Size Distribution in Grinding Plant  

OpenAIRE

This paper presents an analysis of theperformances of an mill grinding circuits. This studyrelieve fineness of cement for certain condition, suchare: ball size distribution, charge of grinding media,weight for all balls from the same category. Becausethe size of media has to match the size of materialbeing ground, it is necessary an analysis of these.Finally, some simulation results are shown.

Costea, Claudiu Raul; Silaghi, Helga; Kovendi, Zoltan

2011-01-01

123

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

Science.gov (United States)

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).

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

2014-10-01

124

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

125

Term Paper Mills Continue to Grind.  

Science.gov (United States)

Cheating by students in academic assignments, especially term papers, cheating on tests, and altering or forging a university document are discussed. Efforts of the University of Maryland to crack down on cheating and to produce a workable code of student conduct are described. (MLW)

Connell, Christopher

1981-01-01

126

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%.

127

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

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} A composite structure roller rings was fabricated by centrifugal casting. {yields} The roller rings consisted of outer WCP/Fe-C composites layer and inner Fe-C alloy matrix. {yields} 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/cm{sup 2}. {yields} The wear resistance of the roller rings excelled that of high-speed steel, and approached to that of the WC hard alloy roll. {yields} The production cost of the WCP/Fe-C composites roller ring decreased by 50%. - Abstract: Tungsten carbide particle (WC{sub P}) 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 WC{sub P} 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 WC{sub P} 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/cm{sup 2}; 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 WC{sub P}-volume-fraction in working-layer were obtained for both of them, but the production cost of the WC{sub P}/Fe-C composites roller ring decreased by 50%.

Song Yanpei, E-mail: sypei@mail.haust.edu.cn [School of Material Science and Engineering, Henan University of Science and Technology, No 48 Xiyuan Road, Luoyang 471003 (China); Li Xiuqing; Bi Shuangxu [School of Material Science and Engineering, Henan University of Science and Technology, No 48 Xiyuan Road, Luoyang 471003 (China)

2010-09-15

128

Development of database and searching system for tool grinding  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: For achieving the goal of saving time on the tool grinding and design, an efficient method of developing the data management and searching system for the standard cutting tools is proposed in this study.Design/methodology/approach: At first the tool grinding software with open architecture was employed to design and plan grinding processes for seven types of tools. According to the characteristics of tools (e.g. types, diameter, radius and so on, 4802 tool data were established in the relational database. Then, the SQL syntax was utilized to write the searching algorithms, and the human machine interfaces of the searching system for the tool database were developed by C++ Builder.Findings: For grinding a square end mill with two-flute, a half of time on the tool design and the change of production line for grinding other types of tools can be saved by means of our system. More specifically, the efficiency in terms of the approach and retract time was improved up to 40%, and an improvement of approximately 10.6% in the overall machining time can be achieved.Research limitations/implications: In fact, the used tool database in this study only includes some specific tools such as the square end mill. The step drill, taper tools, and special tools can also be taken into account in the database for future research.Practical implications: The most commercial tool grinding software is the modular-based design and use tool shapes to construct the CAM interface. Some limitations on the tool design are undesirable for customers. On the contrary, employing not only the grinding processes to construct the grinding path of tools but the searching system combined with the grinding software, it gives more flexible for one to design new tools.Originality/value: A novel tool database and searching system is presented for tool grinding. Using this system can save time and provide more convenience on designing tools and grinding. In other words, the company productivity can be improved.

J.Y. Chen

2008-02-01

129

High Performance Grinding and Advanced Cutting Tools  

CERN Document Server

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.

Jackson, Mark J

2013-01-01

130

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] 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.

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

131

Adsorption of single-strand alkylammonium salts on bentonite, surface properties of the modified clay and polymer nanocomposites formation by a two-roll mill  

International Nuclear Information System (INIS)

The adsorption of tallow alkylammonium salts onto bentonite from the Lopburi province in Thailand, and the effect of surface wettability on the formation of polymer-clay nanocomposites are reported. We looked specifically at octadecyltrimethyl ammonium chloride (S18), a popular member of the tallow alkylammonium salt family. The adsorption of S18 onto the bentonite interlayer can be divided into three distinct stages depending upon the initial concentration of S18. These stages are (a) monolayer formation, (b) intermediate state of double layer formation and (c) double layer formation. A decrease in surface energy driven by drops in the values of the polar and dispersive components was observed as the amount of surfactant surface coverage increased. Using thermal gravimetric analysis (TGA), the critical surface energy (CSE) of organoclay was found to decrease as the amount of absorbed S18 increased. S18 organoclay with different degrees of surface coverage was used in a two-roll mill to prepare high-density polyetheylene (HDPE)-clay nanocomposites. The oxidized polyethylene wax (OWax) was used as a dispersing agent to promote the delamination of the organoclay platelets. The results from X-ray diffraction (XRD) and transmission electron microscope (TEM) indicated a difference in the dispersing capability of the organoclay.

132

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)

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.

Rafiei Masoud

2009-01-01

133

Dynamics of Entangled Polymeric Fluids in Two-roll Mill studied via Dynamic Light Scattering and Two-color flow Birefringence; 1, Steady flow  

CERN Document Server

We present the experimental results on a series of high molecular weight, entangled polystyrene solutions subjected to a ``mixed'' shear and elongational flow-type generated in a co-rotating two-roll mill. For steady-flows as well as for start-up of flows from rest, we used two different optical methods to study the dynamics of entangled polymeric fluids: two-color flow birefringence (TCFB) and dynamic light scattering (DLS). Using the TCFB method, we measured the birefringence, $\\Delta n$, and the orientation angle, $\\chi$, of the optic axes in the solution and thereby the generalized viscosity function, $\\eta$ (with the use of stress-optical relations). The DLS method was applied to measure the velocity-gradient, \\gdot, and the flow-type parameter $\\lambda$ for the polymer solutions under flow conditions identical to the TCFB measurements. For low deformation rates the symmetry of the flow-field was reduced with the use of polymeric fluids compared to that seen with a Newtonian fluid. A molecular constituti...

Sanyal, S; Leal, L C; Sanyal, Subrata; Yavich, Dmitry

2000-01-01

134

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.

135

Applications of High-Efficiency Abrasive Process with CBN Grinding Wheel  

Directory of Open Access Journals (Sweden)

Full Text Available 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 and super-high speed grinding, quick point-grinding, high efficiency deep-cut grinding, creep feed deep grinding, heavy-duty snagging and abrasive belt grinding were summarized. The efficiency and parameters range of these abrasive machining processes were compared. The key technologies of high efficiency abrasive machining, including grinding wheel, spindle and bearing, grinder, coolant supplying, installation and orientation of wheel and workpiece and safety defended, as well as intelligent monitor and NC grinding were investigated. It is concluded that high efficiency abrasive machining is a promising technology in the future.

Yan Zhou

2010-04-01

136

Surface Fine Grinding via a Regenerative Grinding Methodology  

International Nuclear Information System (INIS)

This paper presents a regenerative surface fine grinding methodology to remove grinding defects of traditional operations and to improve the quality of surface flatness. All possible surface defects produced by traditional and creep-feed grinding operations are carefully reviewed and circumvented. These defects include non -uniform traces, pitting spots, scratches, burnouts, and quenching breakage. To alleviate these traditional grinding defects, the paper presents a new approach by designing and constructing a regenerative surface fine grinding system that includes a mechanism that carries the submerged workpart in an oil-contained open box. The fine grinding tool held by the spindle-chuck unit of the CNC machine is moved in relative to the workpart surfaces by a combined trajectory of a cycloid path, a linear feed and a lateral travel. Some numerical simulations for selecting appropriate grinding trajectories are presented and simulated. The trajectory is selected based upon the resulting quality of contact uniformity and homogeneity as expressed in terms of contact frequency to each point on the workpart surface. The simulation model is then used to characterize appropriate working range of each grinding parameter. Different grinding paths are thus generated and superposed. A working machine is designed and built based upon the simulation results. Several experiments are carried out on the constructed grinding system with the grinding tool mounted to the spindle-chhe grinding tool mounted to the spindle-chuck unit of the CNC machine. The surface quality of the ground workpart is measured. Tests on different system parameters demonstrate the importance of choosing the correct grinding wheel and grit size and an illustration of the proper selection of process and system parameters are presented. The experimental results are compared with those of analytical solutions. Good agreement between them is observed. In ninety minutes fine-grinding operations using the proposed method, the workpart surfaces generally possess no damage and surface roughness is reduced to the range of 0.02?0.04?m in Ra. To verify the effectiveness of the proposed method, the results of fine grinding operations using various process parameters are measured and recorded. The effects of various combinations of process parameters including trajectory density, uniformity and grinding efficiency on the effect of surface flatness enhancement are carefully examined and concluded

137

Surface Fine Grinding via a Regenerative Grinding Methodology  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a regenerative surface fine grinding methodology to remove grinding defects of traditional operations and to improve the quality of surface flatness. All possible surface defects produced by traditional and creep-feed grinding operations are carefully reviewed and circumvented. These defects include non -uniform traces, pitting spots, scratches, burnouts, and quenching breakage. To alleviate these traditional grinding defects, the paper presents a new approach by designing and constructing a regenerative surface fine grinding system that includes a mechanism that carries the submerged workpart in an oil-contained open box. The fine grinding tool held by the spindle-chuck unit of the CNC machine is moved in relative to the workpart surfaces by a combined trajectory of a cycloid path, a linear feed and a lateral travel. Some numerical simulations for selecting appropriate grinding trajectories are presented and simulated. The trajectory is selected based upon the resulting quality of contact uniformity and homogeneity as expressed in terms of contact frequency to each point on the workpart surface. The simulation model is then used to characterize appropriate working range of each grinding parameter. Different grinding paths are thus generated and superposed. A working machine is designed and built based upon the simulation results. Several experiments are carried out on the constructed grinding system with the grinding tool mounted to the spindle-chuck unit of the CNC machine. The surface quality of the ground workpart is measured. Tests on different system parameters demonstrate the importance of choosing the correct grinding wheel and grit size and an illustration of the proper selection of process and system parameters are presented. The experimental results are compared with those of analytical solutions. Good agreement between them is observed. In ninety minutes fine-grinding operations using the proposed method, the workpart surfaces generally possess no damage and surface roughness is reduced to the range of 0.02{approx}0.04{mu}m in Ra. To verify the effectiveness of the proposed method, the results of fine grinding operations using various process parameters are measured and recorded. The effects of various combinations of process parameters including trajectory density, uniformity and grinding efficiency on the effect of surface flatness enhancement are carefully examined and concluded.

Lai, H-Y [Institute of Mechanical and Electromechanical Systems National Formosa University, Huwei, Taiwan (China); Chen, C-K [Department of Mechanical Engineering National Cheng-Kung University, Tainan, Taiwan (China)

2006-10-15

138

Surface Fine Grinding via a Regenerative Grinding Methodology  

Science.gov (United States)

This paper presents a regenerative surface fine grinding methodology to remove grinding defects of traditional operations and to improve the quality of surface flatness. All possible surface defects produced by traditional and creep-feed grinding operations are carefully reviewed and circumvented. These defects include non -uniform traces, pitting spots, scratches, burnouts, and quenching breakage. To alleviate these traditional grinding defects, the paper presents a new approach by designing and constructing a regenerative surface fine grinding system that includes a mechanism that carries the submerged workpart in an oil-contained open box. The fine grinding tool held by the spindle-chuck unit of the CNC machine is moved in relative to the workpart surfaces by a combined trajectory of a cycloid path, a linear feed and a lateral travel. Some numerical simulations for selecting appropriate grinding trajectories are presented and simulated. The trajectory is selected based upon the resulting quality of contact uniformity and homogeneity as expressed in terms of contact frequency to each point on the workpart surface. The simulation model is then used to characterize appropriate working range of each grinding parameter. Different grinding paths are thus generated and superposed. A working machine is designed and built based upon the simulation results. Several experiments are carried out on the constructed grinding system with the grinding tool mounted to the spindle-chuck unit of the CNC machine. The surface quality of the ground workpart is measured. Tests on different system parameters demonstrate the importance of choosing the correct grinding wheel and grit size and an illustration of the proper selection of process and system parameters are presented. The experimental results are compared with those of analytical solutions. Good agreement between them is observed. In ninety minutes fine-grinding operations using the proposed method, the workpart surfaces generally possess no damage and surface roughness is reduced to the range of 0.02~0.04?m in Ra. To verify the effectiveness of the proposed method, the results of fine grinding operations using various process parameters are measured and recorded. The effects of various combinations of process parameters including trajectory density, uniformity and grinding efficiency on the effect of surface flatness enhancement are carefully examined and concluded.

Lai, Hsin-Yi; Chen, Chao'-Kuang

2006-10-01

139

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.

140

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

Directory of Open Access Journals (Sweden)

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.

GHEORGHE VOICU

2013-06-01

141

Gravity flow operated small electricity generator retrofit kit to flour mill industry  

OpenAIRE

Flour milling is a grinding process to produce flour from wheat through comprehensive stages of grinding and separation. The primary energy is required to provide power used in grinding of wheat. In wheat milling, tempering is the process of adding water to wheat before milling to toughen the bran and mellow the endosperm. Gravity flow of the wheat is utilized to rotate the dampener wheel with cups to add water. Low cost gravity flow operated small electricity generator retrofit kit for dampe...

Shekara, Prithivi; Kumar V, Pavan; Hosamane, Gangadharappa Gundabhakthara

2011-01-01

142

Finite element analysis of deflection of rolls and its correction by providing camber on rolls  

Directory of Open Access Journals (Sweden)

Full Text Available Rolling process is a key step in the production of flat steel products. Because of automation commonly implemented in flat product rolling mills, the products should meet the requirements of tight tolerances. one of the major defects observed in the rolling process is flatness and lack of attainment of the desired surface profile due to deflection of the rolls. The spatial shape and dimensions of the roll gap are influenced by the elastic deformation of all parts of the rolling stand equipment affected by the roll pressure. The current study aims to determine the variation of the deflection in rolls in a two high mill with varying percentage reduction of the sheet i.e, 20%, 25% and 30% on annealed and non-annealed IF steel sheet and analyzing possible solutions to reduce the elastic deflection of rolls with special emphasis on cambering and modelling of the same in Abaqus CAE.

Vijay Gautam

2013-10-01

143

Computation of Rolling Stand Parameters by Genetic Algorithm  

Directory of Open Access Journals (Sweden)

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.

František ?urovský

2008-05-01

144

Compliant meso-scale grinding of silicon  

Science.gov (United States)

In this research, the need to create complex three-dimensional free-form shapes in silicon wafers for MEMS applications has been identified. Meso-scale grinding was chosen to perform the three-dimensional machining of silicon, among several other machining methods. Traditionally, ultra-rigid ultra-precision machines are used to machine silicon wafers in order to achieve ductile material removal mode to minimize grinding induced surface and subsurface defects. In this research, however, a compliant grinding methodology has been proposed to realize ductile regime material removal and to reduce grinding induced subsurface defects. A compliant meso-scale grinding apparatus, equipped with computer-controlled 3-axis movement, backlash-free flexure feeding and force monitoring, was developed to perform compliant silicon grinding experiments. Contour grinding, traverse grinding and plunge grinding experiments were carried out on the compliant grinding apparatus. These grinding experiments demonstrate that compliant grinding is capable of achieving good form accuracy and mirror surface finish. Further studies on grinding ductility, grinding induced subsurface defects indicate that compliant grinding can increase silicon ductility by 240.7%, reduce subsurface defects by 55.7% when compared with rigid grinding experiments. Based on off-line force analysis both in time domain and frequency domain, a first-cut detection algorithm was developed to detect wheel/workpiece contact in real-time. The algorithm is capable of adjusting to different motor vibrations and environmental noise levels by self-learning. The first-cut detection algorithm was tested successfully in real-time. To further improve form accuracy obtained on the compliant grinding apparatus, a normal grinding force model and a depth of cut model were developed to account for the large compliance in the grinding system. Numerical simulation was performed to predict actual depths of cut and the results were within 6% of the measured/actual depths.

Jiang, Bo

145

Design of the Soymilk Mill based on TRIZ Theory  

Directory of Open Access Journals (Sweden)

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.

Jiang Fan

2013-05-01

146

Large-scale Evaluation of Nickel Aluminide Rolls in a Heat-Treat Furnace at Bethelehem Steel's (Now ISG) Burns Harbor Plate Mill  

Energy Technology Data Exchange (ETDEWEB)

At Bethlehem Steel Burns Harbor Plate Division (now ISG Burns Harbor Plate Inc.)'s annealing furnace, new nickel aluminide intermetallic alloy rolls provide greater high-temperature strength and wear resistance compared to the conventional H series cast austenitic alloys currently used in the industry. Oak Ridge National Laboratory and Bethlehem (ISG) partnered under a U.S. Department of Energy, Office of Industrial Technology's Emerging Technology Deployment Program to demonstrate and evaluate the nickel aluminide intermetallic alloy rolls as part of an updated energy efficient large commercial annealing furnace system. Many challenges were involved in this project, including developing welding procedures for joining nickel aluminide intermetallic alloys with H-series austenitic alloys, developing commercial cast roll manufacturing specifications, working with several commercial suppliers to produce a quantity of high quality, reproducible nickel aluminide rolls for a large steel industrial annealing furnace, installing and demonstrating the capability of the rolls in this furnace, performing processing trials to evaluate the benefits of new equipment and processes, and documenting the findings. Updated furnace equipment including twenty-five new automated furnace control dampers have been installed replacing older design, less effective units. These dampers, along with upgraded flame-safety control equipment and new AC motors and roll-speed control equipment, are providing improved furnace control and additional energy efficiency. Energy data shows up to a 34% energy reduction from baseline after the installation of upgraded furnace damper controls along with up to a 34% reduction in greenhouse gases, potential for an additional 3 to 6% energy reduction per campaign of light-up and shutdown, and a 46% energy reduction from baseline for limited trials of a combination of improved damper control and straight-through plate processing. The straight-through processing is now possible because of the nickel aluminide rolls which also provided plate product surface quality improvement that will allow the additional processing of surface critical material. Benefits also include associated large reductions in maintenance, reduction in spare rolls and associated component costs, and potential for greater through-put and productivity. Estimated project fuel cost reductions alone for processing 100,000 tons/yr through this furnace are almost $0.5 million/yr with the new dampers, and more than $600,000/yr with straight-through processing and new damper control, assuming natural gas prices of $6.00/MMBtu. The nickel aluminide rolls are competitively priced with conventional H series alloy rolls.

Mengel, J.

2003-12-16

147

Rolling Stonesi kinokontsert kannab toorest rokiväge / Maris Meiessaar  

Index Scriptorium Estoniae

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

Meiessaar, Maris

2009-01-01

148

Action of grinding additives on the efficiency of the grinding workshop in a cement factory; Action des agents de mouture sur l`efficacite de l`atelier de broyage  

Energy Technology Data Exchange (ETDEWEB)

Today`s modern grinding additives are the result of 50 years of continual research and development activity combined with detailed analysis of their influence on the cement production process and on cement quality. The action of grinding additives on the efficiency of a grinding workshop can largely be explained by: the prevention of agglomeration and coating of the mill internals; the reduction of time the material stays in the mills; the improved separator efficiency. As a summary the principal advantage of the successful application of a grinding additive concerns the reduction in energy consumption (kWh/tonne) brought about by the enhanced grinding efficiency, the possibility to reduce the target efficiency, the possibility to reduce the target fineness where properties are improved as a result of a narrower particle size distribution and improved hydration characteristics, as well as: the increase in production rate of the mill which is typically of the other order of 10 to 20 %; the ability to maximize the use of the efficient mill system and thereby reduce the need to operate older less efficient grinding systems; the reduction in run time for a given annual capacity that can provide further benefits such as maximizing low cost electricity usage and permitting reduced repair and maintenance costs; the improved flowability that can also provide significant benefits such as an increased rate of loading and unloading operations and during cement storage and transport; last but not least, additives can provide more appropriate cement performance characteristics to meet the local cement market requirements

Anon.

1997-06-01

149

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

Directory of Open Access Journals (Sweden)

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.

Marek Matik

2004-12-01

150

Milling media from zirconia ceramics  

International Nuclear Information System (INIS)

Zirconia ceramics has found applications in various important fields. Oxygen sensors, heating elements, solid electrolytes, cutting tools, high temperature insulation, metal casting dies and nozzles are some of the areas of applications. Milling of zirconia compositions should preferably be done with ZrO2 milling media. Moreover, higher density of ZrO2 (5.5-5.7 gm/cc.) compared to alumina (3.4-3.7 gm/cc) results in faster grinding by zirconia balls. Wear of the grinding jar is also less compared to alumina balls. In the present work grinding balls have been prepared from zirconia, Y2O3, CaO-TiO2 stabilizing agents. (author). 6 refs., 2 figs., 1 tab

151

Analysis of the bimetallic bars rolling during a skew rolling  

OpenAIRE

Purpose: Bimetallic bars which possess higher corrosion resistance and mechanical properties, it is the newkind of bimetallic bars which are better than standard bars. The bimetallic bars are more often applied in concreteconstruction. There are few methods which ensure a good strength of bimetallic layer bond. Hydrostatic extrusion,rotary rolling and explosive cladding are most often used methods.Design/methodology/approach: The simulations of the bar rolling in a three-high skew mill were c...

Sawicki, S.; Szota, P.; Dyja, H.

2008-01-01

152

Developments in precision optical grinding technology  

Science.gov (United States)

Optical systems that utilize complex optical geometries such as aspheres and freeform optics require precise control through the manufacturing process. As the preparatory stage for polishing, this is especially true for grinding. The quality of the grinding process can greatly influence the polishing process and the resultant finished product. OptiPro has performed extensive development work in evaluating components of a precision grinding machine to determine how they influence the overall manufacturing process. For example, spindle technology has a strong effect on how a grinding machine will perform. Through metrology techniques that measure the vibration characteristics of a machine and measurements of grinding forces with a dynamometer, OptiPro has also developed a detailed knowledge of how the machine can influence the grinding process. One of the outcomes of this work has led OptiPro to develop an ultrasonic head for their grinding platform to aid in reducing grinding forces. Initial results show a reduction in force by ~50%.

Fess, Edward; Bechtold, Mike; Wolfs, Frank; Bechtold, Rob

2013-09-01

153

Spray rolling aluminum alloy strip  

International Nuclear Information System (INIS)

Spray rolling combines spray forming with twin-roll casting to process metal flat products. It consists of atomizing molten metal with a high velocity inert gas, cooling the resultant droplets in flight and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets teams with conductive cooling at the rolls to rapidly remove the alloy's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly solidified product. While similar in some ways to twin-roll casting, spray rolling has the advantage of being able to process alloys with broad freezing ranges at high production rates. This paper describes the process and summarizes microstructure and tensile properties of spray-rolled 2124 and 7050 aluminum alloy strips. A Lagrangian/Eulerian poly-dispersed spray flight and deposition model is described that provides some insight into the development of the spray rolling process. This spray model follows droplets during flight toward the rolls, through impact and spreading, and includes oxide film formation and breakup when relevant

154

Efficient Fuel Pretreatment: Simultaneous Torrefaction and Grinding of Biomass  

DEFF Research Database (Denmark)

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.

Saleh, Suriyati Binti; Hansen, Brian Brun

2013-01-01

155

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...

156

Research on grinding block wear in grinding of SiC  

Science.gov (United States)

Silicon carbide is being the main ceramics material to make aspherical optical reflectors because of its good physical and chemical performance. But, because of the particularity of wheel structure, wheel wear form and wear loss is changing with time going, which limits the wheel wear researchment. In order to make a better research to wheel grinding, the author experimented many researches on diamond grinding blocks in grinding of SiC in the surface grinding machine, finding the relationship between diamond grinding block wear form and wear loss and grinding force, surface quality and surface precision of workpiece, including the principle of diamond grinding block wear form and wear loss changing with time going, the influencing law of surface quality and surface accuracy because of wheel wear. By changing some grinding parameters in the grinding experiments, the author gets the order of the influencing factors of grinding parameters to wheel wear by orthogonal test.

Zhang, Feihu; Lu, Guodong; Liu, Minhui; Luan, Dianrong

2014-09-01

157

Automatic programming of grinding robot  

Directory of Open Access Journals (Sweden)

Full Text Available A new programming method is developed for grinding robots. Instead of using the conventional jog-and-teach method, the workpiecc geometry is automatically scanned by a contour tracking system. During tracking of the workpiece contour, the robot position is continuously logged. Finally a robot program is automatically generated.

Trygve Thomessen

1993-04-01

158

Automatic programming of grinding robot  

OpenAIRE

A new programming method is developed for grinding robots. Instead of using the conventional jog-and-teach method, the workpiecc geometry is automatically scanned by a contour tracking system. During tracking of the workpiece contour, the robot position is continuously logged. Finally a robot program is automatically generated.

Trygve Thomessen; Elle, Ole J.; Jon Lund Larsen; Torgrim Andersen; Pedersen, Jahn E.; Lien, Terje K.

1993-01-01

159

Energy consumption reduction in Ring Rolling processes: a FEM analysis  

OpenAIRE

Ring Rolling is a very high energy consuming hot forming process used for the production of shaped ring, seamless and axis symmetrical workpieces. Different production steps (Upsetting, Piercing, Ring Rolling) are involved in generating the desired ring shape. In particular the Upsetting and Piercing steps generate a hollow circular preform that will be subsequently enlarged by the rolling mills (Driver, Idle and Axial Rolls) during the Ring Rolling step. In order to reduce the energy and the...

Giorleo, Luca; Ceretti, Elisabetta; Giardini, Claudio

2013-01-01

160

Thermal study of complex formation of triamterene with ?-cyclodextrin by spray-drying and co-grinding  

OpenAIRE

The formation of crystalline inclusion complex of triamterene with ?-cyclodextrin (?-CD) was studied, evaluating the thermal behaviour and dispersion state of this drug in different types of binary systems. Spray-drying and co-grinding (oscillating mill) mixtures of triameterene with ?-CD were prepared in 1:1 molar ratio. The changes of crystalline properties of original (untreated) triamterene, ?-CD, and composites obtained by co-grinding and spray-drying were investigated in comparison ...

Gine?s, J. M.; Arias Blanco, M. J.; Nova?k, C.; Sa?nchez-soto, Pedro Jose?; Ruiz Conde, Antonio; Morillo Gonza?lez, Esmeralda

1995-01-01

161

Surface grinding of intermetallic titanium aluminides  

CERN Document Server

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

Gröning, Holger Andreas

2014-01-01

162

Force characteristics in continuous path controlled crankpin grinding  

Science.gov (United States)

Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions. Unlike in conventional external cylindrical plunge grinding, the conditions between the grinding wheel and the crankpin change periodically in path controlled grinding because of the eccentricity of the crankpin and the constant rotational speed of the crankshaft. The objective of this study is to investigate the effects of various grinding conditions on the characteristics of the grinding force during continuous path controlled grinding. Path controlled plunge grinding is conducted at a constant rotational speed using a cubic boron nitride (CBN) wheel. The grinding force is determined by measuring the torque. The experimental results show that the force and torque vary sinusoidally during dry grinding and load grinding. The variations in the results reveal that the resultant grinding force and torque decrease with higher grinding speeds and increase with higher peripheral speeds of the pin and higher grinding depths. In path controlled grinding, unlike in conventional external cylindrical plunge grinding, the axial grinding force cannot be disregarded. The speeds and speed ratios of the workpiece and wheel are also analyzed, and the analysis results show that up-grinding and down-grinding occur during the grinding process. This paper proposes a method for describing the force behavior under varied process conditions during continuous path controlled grinding, which provides a beneficial reference for describing the material removal mechanism and for optimizing continuous controlled crankpin grinding.

Zhang, Manchao; Yao, Zhenqiang

2015-03-01

163

Rolling of very thin sheets  

Energy Technology Data Exchange (ETDEWEB)

Thin strip specimens were reduced to foil by passing them repeatedly between the rolls of a two-high mill at low speeds. Narrow specimens were tested to avoid complications caused by roll bending. Factors governing the rate of reduction were examined, these being roll preload value and roll surface finish for low carbon strips as well as material strength, hardness, and anisotropy for aluminum and copper. No minimum thickness was found for the steel specimens; for aluminum and copper limiting thickness values were obtained based on the onset of edge cracking and longitudinal fracture. Thickness values and total number of passes were found to be inversely related. Roll surface finish and preload value affected the rate of reduction in a significant manner; hardness and developing anisotropy did not. 20 refs.

Scrutton, R.F.; Lenard, J.G.

1982-01-01

164

Modulus Proposal for a Multi Axes Grinding of Sculptured Surfaces  

Science.gov (United States)

This paper presents the use of the CAD/CAM system Cimatron for free programming of NC grinding machines. NC technology use, first of all in milling, turning and drilling operations, is widely dispersed at present. Development of these technologies depends to some extent on the cutting tools which are to be produced and sharpened to a high quality. Usable properties of the cutting tools, e.g. the shape accuracy, the quality of function surfaces, etc., are inspired by the production technology used. This technology plays a main role in production and sharpening of powerful and complex shaped cutting tools.

Jande?ka, Karel

2009-11-01

165

Grinding assembly, grinding apparatus, weld joint defect repair system, and methods  

Science.gov (United States)

A grinding assembly for grinding a weld joint of a workpiece includes a grinder apparatus, a grinder apparatus includes a grinding wheel configured to grind the weld joint, a member configured to receive the grinding wheel, the member being configured to be removably attached to the grinder apparatus, and a sensor assembly configured to detect a contact between the grinding wheel and the workpiece. The grinding assembly also includes a processing circuitry in communication with the grinder apparatus and configured to control operations of the grinder apparatus, the processing circuitry configured to receive weld defect information of the weld joint from an inspection assembly to create a contour grinding profile to grind the weld joint in a predetermined shape based on the received weld defect information, and a manipulator having an end configured to carry the grinder apparatus, the manipulator further configured to operate in multiple dimensions.

Larsen, Eric D.; Watkins, Arthur D.; Bitsoi, Rodney J.; Pace, David P.

2005-09-27

166

The effects of pf grind quality on coal burnout in a 1 MW combustion test facility  

Energy Technology Data Exchange (ETDEWEB)

A study was carried out to determine the effect of pf particle size distribution on coal burnout propensity in a 1 MW pulverised fuel burner. The specific aim of the work was to assess the improvement in combustion performance achievable by retrofitting commercially available high performance static or dynamic classifiers to existing plants. Two coals were used and were selected as representative of extremes in fuel characteristics experienced by coal importing utilities in Europe. Each coal was fired in the unit at a range of grind sizes to determine the overall impact of a variable performance from a mill. The levels of unburnt carbon in the resultant flyashes for the two coals showed significantly different behaviour. For the higher volatile coal, the unburnt carbon was found to be insensitive to grind quality. However, the coarser grinds of the other coal produced significantly lower unburnt carbon than expected when compared with the finest grinds. Generally the results indicate that the installation of improved classification technology, leading to a finer product, will help to lower unburnt carbon levels. Nevertheless, further work will be necessary to establish the levels of diminishing returns for grind size, burnout performance and grind costs. 21 refs., 4 figs., 4 tabs.

Richelieu Barranco; Michael Colechin; Michael Cloke; Will Gibb; Edward Lester [University of Nottingham, Nottingham (United Kingdom). School of Chemical, Environmental and Mining Engineering, Nottingham Fuel and Energy Centre

2006-05-15

167

Simulation analysis of grinding wheel motion trajectory on SiC ceramics aspheric surface grinding  

Science.gov (United States)

In grinding process of SiC ceramics aspheric surface, the motion trajectory of grinding wheel has great influence on the surface forming. The paper provides mathematical models of grinding wheel movements; analytical simulation was done to describe the trajectories of the grinding wheel in manufacturing an aspherical workpiece. The effect of grinding parameters (including the rotation speed of the workpiece, the feed rate of grinding wheel etc.) on the aspheric surface coverage rate was conducted and discussed in detail. An experimental study was done according to the simulation results and an aspheric surface with form error less than 10?m was gained.

Zhang, Feihu; Liu, Lifei; Li, Chunhui

2014-08-01

168

Online SAG Mill Pluse Measurement and Optimization  

Energy Technology Data Exchange (ETDEWEB)

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.

Raj Rajamani; Jose Delgadillo; Vishal Duriseti

2007-06-30

169

Effect of plate asymmetric rolling parameters on the change of the total unit pressure of roll  

OpenAIRE

This work shows the results of theoretical analysis of asymmetric rolling process of plates in the finishing mill of plate rolling. Its aim was to determine the influence of asymmetry velocity of working rolls on decrease of unit pressure of metal on the rolls. The lower value of the unit pressure will reduce the elastic deflection of the finishing stand and improve the cross-section shape of plate. Three-dimensional simulation of asymmetric hot rolling of S355J2G3 steel plates was done with ...

Kawalek, A.; Dyja, H.; Mroz, S.; Knapinski, M.

2011-01-01

170

Prevention of rolled-in defects in cold-rolled ultra-low carbon steels  

International Nuclear Information System (INIS)

The cause of the surface defect in the cold-rolled ultra-low carbon steel was investigated through the analyses of the chemical composition and the size of the defect itself and of the correlation between the defect and the surface deterioration of the finishing work roll in the hot strip mill. It was found that the surface defect was originated from the surface peeling of the fourth finishing work roll, which was related to the severe thermal fatigue damage due to higher hot-rolling temperature. The amount of the defective strips was considerably decreased by intermediate change of the fourth work roll and by increasing the roll coolant and the lubricant. The defect was also decreased by reducing the number of the ultra-low carbon steel coils in one rolling campaign. Complete prevention was achieved by changing the roll material from nickel-grain cast iron to high-chromium cast iron with the superior thermal fatigue property

171

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)

172

Wedge - rolls rolling of hollowed parts  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Presentation of the possibilities of application of a new manufacturing method, called wedge rollsrolling (WRR in forming of axi – symmetrical hollowed parts.Design/methodology/approach: The research work was done in a specially designed laboratory rolling millLUW-2. During the research, hollowed parts from steel were rolled in hot forming conditions. Basic kinematicaland force parameters of the process were noticed during rolling.Findings: On the basis of the conducted research it was stated that the WRR method could be used for formingof hollowed parts with the precision compared with the precision obtained in the typical cross wedge rollingprocesses (CWR. At the same time, it was proved that this method could be used for rolling from billets withthe wall thinner than the wall given in the CWR.Research limitations/implications: The research were limited to the wedges with spreading angles withinrange of ? = (5° ÷ 9°, with the constant values of forming angle ? = 30° and relative reduction ratio ? = 1.45.In the future, it is planned to analyse the influence of changes of angle ? and relative reduction ratio ? on theWRR process.Practical implications: The conducted research can be used for designing of a new industrial method of metalforming of hollowed parts.Originality/value: The innovation of this solution is based on the application of only one wedge for forming.Because of that, the WRR method is cheaper for implementation than used so far CWR processes. This methodcan be applied mainly in automotive and aviation industries.

Z. Pater

2006-08-01

173

Dynamics of Entangled Polymeric Fluids in Two-roll Mill studied via Dynamic Light Scattering and Two-color flow Birefringence. II. Transient flow  

CERN Document Server

We present an extensive experimental study of birefringence and velocity-gradient components for a series of high molecular weight, flexible, entangled polystyrene solutions subjected to transient start-up flows in a co-rotating two-mill to several Weissenberg numbers. The time-dependent changes in the polymer microstructure, as measured by a two-color flow birefringence technique, is shown to be very distinctly coupled with the transient response of the corresponding velocity-field, measured by a dynamic light scattering technique. As expected, polymer deformations induce substantial modifications from the Newtonian flow-field. As a result, measured values of both velocity-gradient components as well as flow-type parameter reduce, thereby drastically decreasing the extensional strength or measured Weissenberg number at the stagnation-point relative to the velocity-field for a Newtonian fluid. Although the impact of the dynamics of both polymer on flow and flow on polymer are very complicated, their individua...

Sanyal, S; Leal, L C; Sanyal, Subrata; Yavich, Dmitry

2000-01-01

174

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

OpenAIRE

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 ...

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

2014-01-01

175

Manufacturing processes 2 grinding, honing, lapping  

CERN Document Server

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).

Klocke, Fritz

2009-01-01

176

Effect of reactive mechanical grinding on chemical and hydrogen sorption properties of the Mg+10 wt.% Co mixture.  

OpenAIRE

Reactive mechanical grinding (MG under H2) of magnesium powder improves the hydrogen sorption properties. The hydrogenation of Mg starts in situ during the milling process that allows suppressing the activation procedure generally requested for Mg. The addition of Co, which acts as a catalyst for the dissociation of H2, also leads to an improvement of the hydrogen sorption properties (but a strong dependence upon the milling time is reported). The hydriding is determined to be a two-step proc...

Bobet, Jean-louis; Chevalier, Bernard; Darriet, Jacques

2002-01-01

177

Surface Grinding Machine Stability Characteristics Limited Prediction  

Directory of Open Access Journals (Sweden)

Full Text Available 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 experiments. Flutter stability prediction method provides a theoretical basis in selecting the grinding process parameters for the machine processing operators and it also has an important meaning to the work piece surface quality and processing efficiency.

Yuting Yang

2012-07-01

178

Precision diamond grinding of ceramics and glass  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1988-12-01

179

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

Directory of Open Access Journals (Sweden)

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.

Števulová Nadežda

2002-06-01

180

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

Index Scriptorium Estoniae

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

Russmann, Raivo

2006-01-01

181

Improved coal grinding and fuel flow control in thermal power plants  

DEFF Research Database (Denmark)

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.

Niemczyk, Piotr; Bendtsen, Jan Dimon

2011-01-01

182

Crystalline silica dust and respirable particulate matter during indoor concrete grinding - wet grinding and ventilated grinding compared with uncontrolled conventional grinding.  

Science.gov (United States)

The effectiveness of wet grinding (wet dust reduction method) and ventilated grinding (local exhaust ventilation method, LEV) in reducing the levels of respirable crystalline silica dust (quartz) and respirable suspended particulate matter (RSP) were compared with that of uncontrolled (no dust reduction method) conventional grinding. A field laboratory was set up to simulate concrete surface grinding using hand-held angle grinders in an enclosed workplace. A total of 34 personal samples (16 pairs side-by-side and 2 singles) and 5 background air samples were collected during 18 concrete grinding sessions ranging from 15-93 min. General ventilation had no statistically significant effect on operator's exposure to dust. Overall, the arithmetic mean concentrations of respirable crystalline silica dust and RSP in personal air samples during: (i) five sessions of uncontrolled conventional grinding were respectively 61.7 and 611 mg/m(3) (ii) seven sessions of wet grinding were 0.896 and 11.9 mg/m(3) and (iii) six sessions of LEV grinding were 0.155 and 1.99 mg/m(3). Uncontrolled conventional grinding generated relatively high levels of respirable silica dust and proportionally high levels of RSP. Wet grinding was effective in reducing the geometric mean concentrations of respirable silica dust 98.2% and RSP 97.6%. LEV grinding was even more effective and reduced the geometric mean concentrations of respirable silica dust 99.7% and RSP 99.6%. Nevertheless, the average level of respirable silica dust (i) during wet grinding was 0.959 mg/m(3) (38 times the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit value [TLV] of 0.025 mg/m(3)) and (ii) during LEV grinding was 0.155 mg/m(3) (6 times the ACGIH TLV). Further studies are needed to examine the effectiveness of a greater variety of models, types, and sizes of grinders on different types of cement in different positions and also to test the simulated field lab experimentation in the field. PMID:17763068

Akbar-Khanzadeh, Farhang; Milz, Sheryl; Ames, April; Susi, Pamela P; Bisesi, Michael; Khuder, Sadik A; Akbar-Khanzadeh, Mahboubeh

2007-10-01

183

Grinding induced martensite on the surface of rails  

DEFF Research Database (Denmark)

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.

Rasmussen, C.J.; Zhang, Xiaodan

2014-01-01

184

Effects of grinding environment on the flotation of Rosh Pinah complex Pb/Zn ore  

OpenAIRE

The Rosh Pinah orebody is a complex lead–zinc sulphide system with pyrite gangue and minor amounts of copper. Laboratory scale milling and flotation testing of ore samples taken from this operation was performed. Different grinding media and conditions were used, including ceramic, stainless steel and steel. Flotation tests used a sequential recovery protocol for selective flotation of first the lead and thereafter the zinc. The presence of species of oxidation products on the ore after mil...

Wei, Y.; Sandenbergh, R. F.

2007-01-01

185

The analysis of the asymmetric plate rolling process  

Directory of Open Access Journals (Sweden)

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.

A. Kawa?ek

2007-08-01

186

Progress in abrasive and grinding technology  

CERN Document Server

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

Xu, Xipeng

2009-01-01

187

Analysis of the bimetallic bars rolling during a skew rolling  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Bimetallic bars which possess higher corrosion resistance and mechanical properties, it is the newkind of bimetallic bars which are better than standard bars. The bimetallic bars are more often applied in concreteconstruction. There are few methods which ensure a good strength of bimetallic layer bond. Hydrostatic extrusion,rotary rolling and explosive cladding are most often used methods.Design/methodology/approach: The simulations of the bar rolling in a three-high skew mill were carriedout using the Forge2005® commercial program.Findings: The higher value of yield stress of the cladding layer does not produce the effect of “flowing down” ofthis layer over the core surface and it’s folding between the rolls. The use of non-corrosive steel on plating layerassures receipt on a high durability and esthetics bimetallic bars.Practical implications: Bimetallic bars are chiefly used in the building industry at production of concreteconstructions, and as working elements in bridge building in aggressive environment.Originality/value: Production of bimetallic bars is very difficult. One from many problems during productionbimetallic bars is assurance good strength of bimetallic layer bond. A theoretical analysis of bimetallic bar rollingin a three-high skew mill is presented in the paper and the distributions of stress and strain intensities in thebimetallic bar during skew rolling are shown.

S. Sawicki

2008-07-01

188

Shear-mode grinding force criteria of Zerodur and Pyrex  

Science.gov (United States)

Experimental grinding of Zerodur and Pyrex demonstrated shear-mode grinding criteria (SM' GFC), which is a repeatable deterministic function of grinding conditions including materials and grinding wheels. Both criteria as with BK7 glass previously reported, are found to be the logarithmic function of removal rate.

Hashimoto, Hiroshi; Imai, Kenichiro

1995-08-01

189

Demand side management of a run-of-mine ore milling circuit  

OpenAIRE

Increasing electricity costs coupled with lower prices for some metals such as platinum group metals require a reevaluation of the operation of grinding processes. Demand side management (DSM) has received increasing attention in the field of industrial control as an opportunity to reduce operating costs. DSM through grinding mill power load shifting is presented in this paper using model predictive control and a real-time optimizer. Simulation results indicate that mill power load shifting c...

Matthews, B.; Craig, Ian K.

2013-01-01

190

Reaction of niobium with hexane and methanol by mechanical grinding  

International Nuclear Information System (INIS)

In mechanical alloying (MA) processing, alcohol, acetone and other organic solvents are often added as dispersants in order that powders will not stick to a vessel. It has been however considered that these organic solvents are simply additives. Enough attention has not been paid to the role or reaction of these dispersants. Recently, it was found that these organic solvents could react with some metals. For example, the authors reported that NbC is obtained by a reaction between Nb and methanol in the preparation of Al3Nb intermetallics by the MA method. Niobium hydrides are obtained by milling of Nb powders in hydrocarbon. In this paper, the authors discuss the reaction between Nb powder and hexane (C6H14) or methanol (CH3OH) during mechanical grinding (MG) processing

191

Analysis of the cutting fluid influence on the deep grinding process with a CBN grinding wheel  

Directory of Open Access Journals (Sweden)

Full Text Available The application of cutting fluid in a deep grinding process is becoming more and more important, mainly where the cutting fluids are used as an "external" agent to the grinding conditions. The role of the fluid in grinding operations is in refrigeration of the workpiece, removal of the shavings, lubrication of the grinding zone, and refrigeration and cleaning of the wheel. The efficiency of a cutting fluid will depend mainly of the type of fluid that will be used. In this work, the influences of the type of cutting fluid used in a deep grinding process of the steel VC131 using CBN grinding wheel are analyzed. Three different types of cutting fluids were used: a vegetable emulsion, a synthetic solution and a integral oil. The variables analyzed during and after the grinding process were the grinding force, the superficial roughness, the acoustic emission (EA, the temperature of the piece and the G ratio (relationship between the volume of material removed from the piece and the volume worn off the grinding wheel. The integral oil showed the best performance relative to the following output variables: EA, cutting force and G ratio. The vegetal emulsion was the fluid that best dissipated heat from the cutting region.

Ronaldo Yoshinobu Fusse

2004-09-01

192

Analysis of the cutting fluid influence on the deep grinding process with a CBN grinding wheel  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The application of cutting fluid in a deep grinding process is becoming more and more important, mainly where the cutting fluids are used as an "external" agent to the grinding conditions. The role of the fluid in grinding operations is in refrigeration of the workpiece, removal of the shavings, lub [...] rication of the grinding zone, and refrigeration and cleaning of the wheel. The efficiency of a cutting fluid will depend mainly of the type of fluid that will be used. In this work, the influences of the type of cutting fluid used in a deep grinding process of the steel VC131 using CBN grinding wheel are analyzed. Three different types of cutting fluids were used: a vegetable emulsion, a synthetic solution and a integral oil. The variables analyzed during and after the grinding process were the grinding force, the superficial roughness, the acoustic emission (EA), the temperature of the piece and the G ratio (relationship between the volume of material removed from the piece and the volume worn off the grinding wheel). The integral oil showed the best performance relative to the following output variables: EA, cutting force and G ratio. The vegetal emulsion was the fluid that best dissipated heat from the cutting region.

Ronaldo Yoshinobu, Fusse; Thiago Valle, França; Rodrigo Eduardo, Catai; Leonardo Roberto da, Silva; Paulo Roberto de, Aguiar; Eduardo Carlos, Bianchi.

2004-09-01

193

Mill’s Perfectionism  

Directory of Open Access Journals (Sweden)

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.

PIERGIORGIO DONATELLI

2006-12-01

194

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)

195

Modelling of dynamic contact length in rail grinding process  

Science.gov (United States)

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.

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

2014-09-01

196

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

OpenAIRE

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 ...

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

2009-01-01

197

Effect of plate asymmetric rolling parameters on the change of the total unit pressure of roll  

Directory of Open Access Journals (Sweden)

Full Text Available This work shows the results of theoretical analysis of asymmetric rolling process of plates in the finishing mill of plate rolling. Its aim was to determine the influence of asymmetry velocity of working rolls on decrease of unit pressure of metal on the rolls. The lower value of the unit pressure will reduce the elastic deflection of the finishing stand and improve the cross-section shape of plate. Three-dimensional simulation of asymmetric hot rolling of S355J2G3 steel plates was done with the aid of FORGE 2008® software. The tensor polynomial interpolation was used for comparing the values of the unit pressure obtaining from symmetric and asymmetric rolling.

A. Kawalek

2011-07-01

198

Theoretical and experimental investigation of grinding marks in sphere NC grinding process  

Science.gov (United States)

Sphere ultra-precision NC grinding process with diamond cup wheel is widely used as an indispensable working procedure for manufacturing spherical, most aspherical, and some freeform surfaces. This paper presents a mathematic model of sphere grinding with cup diamond wheel based on homogeneous transformation method to simulate grinding marks. Different kinds of grinding marks are obtained by changing the geometrical parameters including the shift in axis X and Y axis and inclination angle deviation. Form accuracy and dimensional errors caused by geometrical parameters are also analyzed, and hence a three-step method utilizing grinding marks is proposed to correct these errors. A series of experiments are conducted and the results show that the proposed method is very efficient and effective in actual spherical surface generating process.

Wang, Peng; Zhang, Hao; Hui, Changshun

2014-08-01

199

Mechanical of beryllium deformation and hardening at cold rolling  

International Nuclear Information System (INIS)

Beryllium rolling has been made on DUO-80 mills and quarto 15-35 with reductions of 0.2-1.0% for the run. A mechanism of beryllium deformation at cold rolling is determined by dislocations interaction with additive inclusions. The fracture of inclusion with microcracks formations is possible during deformation. At cold rolling of beryllium it is necessary to control the value of tensile stress in the metal to prevent the propagation of microcracks formed during inclusons cutting

200

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)

201

Delamination of hexagonal boron nitride in a stirred media mill  

Energy Technology Data Exchange (ETDEWEB)

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.

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

202

Optimal Control of Cylindrical Plunge Grinding Using Dynamic Programming  

Science.gov (United States)

An optimal grinding control scheme for cylindrical plunge grinding is proposed in this paper. The proposed grinding control scheme provides the optimal dressing and grinding parameters for batch production. The proposed control scheme consists of a G.A. (Genetic Algorithm) and dynamic programming. The optimized grinding parameters, in accordance with the state variable per cycle, are determined by the G.A. and dynamic programming is applied to ascertain the optimal grinding and dressing parameters for the overall batch. To evaluate the performance of the proposed scheme, off-line simulations based on the experimental data are conducted.

Choi, Jeongju

203

Vibration characteristics analysis of a 20-high Sendzimir mill with localized defect on the working roller  

International Nuclear Information System (INIS)

The working roller associating with local defect of the twenty-high roll mill not only significantly affects the mill performance, but also reduces surface quality of the strip steel. In this paper, the roll mill model with local defect on the working roller is established. The dynamic rolling process is simulated using the Finite Element Analysis. Effects of the local defect on the vibration characteristics of the roll mill and the surface quality of the strip steel are presented. The calculated results are validated using experimental data.

204

Microwave-assisted grinding of metallurgical coke  

International Nuclear Information System (INIS)

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)

205

Studying possibilities to improve the functional properties of metallurgical rolls  

OpenAIRE

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...

Stradomski, Z.; Pirek, A.; Stachura, S.

2008-01-01

206

Effect of deep cryogenic treatment on the microstructure and wear performance of Cr-Mn-Cu white cast iron grinding media  

Science.gov (United States)

The phase transformation and grinding wear behavior of Cr-Mn-Cu white cast irons subjected to destabilization treatment followed by air cooling or deep cryogenic treatment were studied as a part of the development program of substitute alloys for existing costly wear resistant alloys. The microstructural evolution during heat treatment and the consequent improvement in grinding wear performance were evaluated with optical and scanning electron microscopy, X-ray diffraction analysis, bulk hardness, impact toughness and corrosion rate measurements, laboratory ball mill grinding wear test etc. The deep cryogenic treatment has a significant effect in minimizing the retained austenite content and converts it to martensite embedded with fine M7C3 alloy carbides. The cumulative wear losses in cryotreated alloys are lesser than those with conventionally destabilized alloys followed by air cooling both in wet and dry grinding conditions. The cryotreated Cr-Mn-Cu irons exhibit comparable wear performance to high chromium irons.

Vidyarthi, M. K.; Ghose, A. K.; Chakrabarty, I.

2013-12-01

207

Modeling of the process of coal grinding  

Directory of Open Access Journals (Sweden)

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.

T. Wylecia?

2013-04-01

208

Physical fabrication of colloidal ZnO nanoparticles combining wet-grinding and laser fragmentation  

Energy Technology Data Exchange (ETDEWEB)

Combination of wet-grinding and laser fragmentation is a promising approach to advance both methods: Laser fragmentation will be more efficient when combined with mechanical treatment and wet-grinding may take advance of the abrasion-free laser process to achieve fabrication of smaller particles. By mechanical pre-treatment of zinc oxide microparticles in a stirred-media mill, the starting material is activated by generation of crystallographic defects, which strongly enhance the efficiency of subsequent laser fragmentation. Picosecond-laser irradiation of mechanically treated and untreated microparticles suspended in water yielded in colloidal zinc oxide nanoparticles. Furthermore, nanoparticle productivity and properties can be controlled by variation of anionic surfactant concentration. (orig.)

Wagener, Philipp; Lau, Marcus; Barcikowski, Stephan [University of Duisburg-Essen, Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CeNIDE), Essen (Germany); Breitung-Faes, Sandra; Kwade, Arno [Technische Universitaet Braunschweig, Institute for Particle Technology, Braunschweig (Germany)

2012-09-15

209

Energy requirement for fine grinding of torrefied wood  

Energy Technology Data Exchange (ETDEWEB)

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 energy and particle size distribution. It accounts the energy required for grinding particles to sizes inferior to 200 {mu}m, for given grinding conditions. Torrefaction is characterised by the anhydrous weight loss (AWL) of wood. For AWL inferior to around 8%, grinding energy decreases fast. Over 8%, grinding energy decreases at a slow rate. Particle size distribution decreases linearly as the AWL increases. Both for spruce and beech, the grinding criterion is decreased of 93% when the AWL is around 28%. (author)

Repellin, Vincent; Govin, Alexandre; Guyonnet, Rene [Department of Powder and Multi-Components Materials (PMMC), SPIN Research Center, Ecole des Mines de Saint Etienne (EMSE), 158 Cours Fauriel, F-42023 Saint-Etienne (France); Rolland, Matthieu [Process Developments and Engineering Division, Chemical Engineering Department, Institut Francais du Petrole (IFP-Lyon), F-69390 Vernaison (France)

2010-07-15

210

Critical review of Nanofluid Minimum Quantity Lubrication for Grinding application  

Directory of Open Access Journals (Sweden)

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.

Mr. Prashant J. Patil,

2014-08-01

211

Effect of high-pressure coolant Jet on grinding temperature, chip and surface roughness in grinding AISI-1040 Steel  

OpenAIRE

Grinding can be described as a multi-tooth metal cutting operation in which material is generally removed by shearing and ploughing in the form of micro sized chips by the abrasive grits of the grinding wheel. As a result, high temperature is produced in the grinding zone due to large negative rake and high cutting speed of the grinding wheel. Suitable cutting fluid is employed to reduce the temperature through cooling and lubrication in the cutting zone. As conventionally applied cutting flu...

Siddiqui, A. T.; Dhar, N. R.; Rashid, M. H.

2006-01-01

212

The Inlet Engine Valves Grinding Using Different Types of Cutting Fluids and Grinding Wheels  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english In this paper an experimental research is presented in which different types of cutting fluids (a cutting oil and three different types of soluble oils) and grinding wheels (alumina and vitrified CBN) were tested in the inlet engine valves grinding. As evaluation parameters the workpiece residual st [...] ress and the grinding wheel wear were analyzed. The cutting fluid and the grinding wheel types adopted resulted in changes in all the parameters, due to the different lubricant abilities among the fluids and due to the differences in the mechanical and thermal properties among the abrasives tested. For grinding this steel, the CBN wheel is the best choice, mainly due to compressive residual stress results obtained for all cutting fluids tested. The cutting oil is the most adequate cutting fluid to be used, due to its higher lubricity and ability in keeping the wheel sharp for longer periods of time, reducing the overall grinding energy and the thermal damage.

Eraldo Jannone da, Silva; Eduardo Carlos, Bianchi; João Fernando Gomes de, Oliveira; Paulo Roberto de, Aguiar.

2002-06-01

213

Adaptive Automatic Gauge Control of a Cold Strip Rolling Process  

OpenAIRE

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 va...

Roman, N.; Ceanga, E.; Bivol, I.; Caraman, S.

2010-01-01

214

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

Scientific Electronic Library Online (English)

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.

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

2012-07-01

215

Evaluation of roll compaction as a preparation method for hydroxypropyl cellulose-based matrix tablets  

OpenAIRE

Roll compaction was applied for the preparation of hydroxypropyl cellulose (HPC)-based sustained-release matrix tablets. Matrix tablets made via roll compaction exhibited higher dosage uniformity and faster drug release than direct-compacted tablets. HPC viscosity grade, roll pressure, and milling speed affected tablet properties significantly. Roll compaction seems to be an adequate granulation method for the preparation of HPC-based matrix tablets due to the simplicity of the process, less ...

Jeon, Imjak; Gilli, Tiziana; Betz, Gabriele

2011-01-01

216

Progressive hull removal from barley using the Fitzpatrick comminuting mill  

Science.gov (United States)

The objective of the study was to explore an alternative use of the Fitzpatrick Comminuting Machine: to use it to remove the hull from hulled barley while keeping the barley kernel intact. Traditionally, this mill is used to grind material, but we have recently discovered that it also has the abili...

217

Observed Binary Fraction Sets Limits on the Extent of Collisional Grinding in the Kuiper Belt  

CERN Document Server

The size distribution in the cold classical Kuiper belt can be approximated by two idealized power laws: one with steep slope for radii R>R* and one with shallow slope for Rroll-over at R* can be the result of extensive collisional grinding in the Kuiper belt that led to the catastrophic disruption of most bodies with Rroll-over could indeed be explained by collisional grinding provided that the initial mass in large bodies was much larger than the one in the present Kuiper belt, and was dynamically depleted. In addition to the size distribution changes, our code also tracks the effects of collisions on binary systems. We find that it is generally easier to dissolve wide binary systems, such as the ones existing in the cold Kuiper belt today, than to catastrophically disrupt objects with R~R*. Thus, the binary survival sets important lim...

Nesvorny, David; Bottke, William F; Noll, Keith; Levison, Harold F

2011-01-01

218

Preparation of high concentration coal-water slurry fuel by single-step wet grinding  

Energy Technology Data Exchange (ETDEWEB)

This paper reports the results of the study carried out with the coals from north - eastern region of the country (Challenging from Meghalaya and Ledo from Makum field in Assam) on the preparation of HCCS by a single - step wet grinding process. The single - step wet grinding process gives a distinct advantage over dry grinding in respect of milling time and slurry viscosity which are reduced by 20-25% and 25-30% respectively. The shelf-life of such slurry improves from 7 to 20 days. A linear relationship of the slurry viscosity with respect to the coal loading (in the range of 65-70%) and coal characteristics in terms of ash, hygroscopic moisture, maximum moisture and oxygen contents is obtained with a correlation coefficient of 0.99. The slurry was burnt successfully in a 30 kg/h test rig. The results indicate that low ash coals of north-eastern region can be effectively utilised for providing HCCS as a fuel oil substitute.

Prasad, M.; Mall, B.K.; Basu, S.K. [Central Fuel Research Inst., Dhanbad (India)] [and others

1997-07-01

219

Dressing of diamond grinding wheels by abrasive water jet for freeform optical surface grinding  

Science.gov (United States)

During the ultra-precision grinding of a large aperture mirror made of RB-SiC, the grinding wheel becomes dull rapidly, which will lead to an increase of grinding force and a decrease of grinding ratio. In this paper, diamond grinding sticks were dressed with micro SiC abrasive water jet and water jet. Through single factorial experiments, the influence of jet pressure on the dressing performance was investigated. To analyze and evaluate the effect of dressing quantitatively, the 3D roughness and the wheel topography were measured and compared with laser scanning confocal microscope before and after dressing. The experimental results show that the abrasive grains are well protruded from binder and the distribution of the abrasive grains becomes uniform after dressing by abrasive water jet when the dressing parameters are properly selected. The dressing performance of abrasive water jet is much better than water jet. For dressing ultra-fine grit size wheels, the abrasive size of the jet should be smaller than the wheel grit size to achieve a better result. The jet pressure is an obvious influence factor of the surface topography.

Wang, Wei; Yao, Peng; Li, Chengwu; Huang, Chuanzhen; Wang, Jun; Zhu, Hongtao; Liu, Zengwen

2014-08-01

220

Development of concrete floor grinding machine  

International Nuclear Information System (INIS)

In order to provide a flat concrete floor, we have developed a new concrete grinding machine, which is equipped with a rotating diamond wheel, mounted on XYZ translator controlled by PLC digital program controller. By measuring the surface level for several points on work area, and set the target level by external reference, then start machine grinding according to programmed data. It typically takes a few hours to complete one working area of 1 m x 1 m square for 5 mm grind. Current machine is capable to finish levelling within 50 ?m for 1 m span, and surface roughness rms 20 ?m for 1 m, and 10 ?m for 0.1 m. Once we have a flat floor, we may locate hardware component directly on it, without using base plate and level adjustment screws, thus the connection between the component and the concrete floor becomes tight, which provides a very large equivalent mass on the component (a part of the ground becomes linked virtual mass to the component), which drastically reduces the mechanical vibration. This type of technique will be also applicable to industrial use, such as, setting a fine mechanical machining tool or process equipments which require quiet environment. (author)

221

NORMAL PRESSURE AND FRICTION STRESS MEASUREMENT IN ROLLING PROCESSES  

DEFF Research Database (Denmark)

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.

Henningsen, Poul; Arentoft, Mogens

2005-01-01

222

OPTIMISE - Deliverable D4.1, Deliver preliminary samples made by two axis rolling to UNIVERSITY OF TWENTE, month 6  

DEFF Research Database (Denmark)

This report describes the preliminary samples that were delivered to University of Twente (UT). It was decided not to deliver samples made by two axis rolling but instead deliverer samples which were reduce by square drawing and flat rolled in a standard rolling mill. The reason for that will be explained before the results from the actual deliverables will be described.

Eriksen, Morten

2002-01-01

223

An FE Based On-line Model for the Prediction of Work Roll Thermal Profile in Hot Strip Rolling  

Science.gov (United States)

Prediction and control of the thermal deformation of the work roll is vital for enhancing product quality in hot strip and plate rolling. In this paper, we present an on-line model for the prediction of the work roll thermal profile. The model is developed on the basis of an integrated finite element model for the coupled analysis of heat transfer and deformation occurring at the bite zone, to rigorously take into account the effect of various rolling parameters on the thermal behavior of the work roll. The validity of the model is demonstrated through comparison with measurements made in an industrial hot strip mill. Also, an emphasis is given to the examination the effect of some selected rolling parameters in an actual production environment.

Choi, Ji Won; Lee, Jung Hyeung; Sun, Cheng Gang; Hwang, Sang Moo

2010-06-01

224

Effects of hot-rolling temperature and reduction ratio on edge cracking of hot-rolled boron-stainless steel  

International Nuclear Information System (INIS)

The effects of hot-rolling temperature and reduction ratio on edge cracking in hot-rolled stainless steel containing 1.1% boron were investigated by using a hot-mill simulator. The main results are as follows: (1) The temperature at the side of hot-rolled steel sheets (Ts) during hot-rolling was significantly lower than at the center of hot-rolled steel sheets (Tp) just before hot rolling. (2) Ts at the start of edge cracking was not constant and increased with increasing reduction per pass. (3) The total reduction until the start of edge cracking was constant and was not dependent on Ts or the reduction per pass. (4) It is concluded that total reduction is the main factor in edge cracking due to rapid work hardening of the matrix (?phase), and owing to cavities occurring at the interface of the matrix and boride under constant strain conditions. (author)

225

Effects of hot-rolling temperature and reduction ratio on edge cracking of hot-rolled boron-stainless steel  

Energy Technology Data Exchange (ETDEWEB)

The effects of hot-rolling temperature and reduction ratio on edge cracking in hot-rolled stainless steel containing 1.1% boron were investigated by using a hot-mill simulator. The main results are as follows: (1) The temperature at the side of hot-rolled steel sheets (Ts) during hot-rolling was significantly lower than at the center of hot-rolled steel sheets (Tp) just before hot rolling. (2) Ts at the start of edge cracking was not constant and increased with increasing reduction per pass. (3) The total reduction until the start of edge cracking was constant and was not dependent on Ts or the reduction per pass. (4) It is concluded that total reduction is the main factor in edge cracking due to rapid work hardening of the matrix ({gamma}phase), and owing to cavities occurring at the interface of the matrix and boride under constant strain conditions. (author)

Morikawa, Hiroshi; Yamamoto, Osamu; Takemoto, Toshihiko [Nisshin Steel Co. Ltd., Tokyo (Japan)

1998-04-01

226

Remote-controlled grinding robot system for repair work  

Energy Technology Data Exchange (ETDEWEB)

A new teleoperated grinding robot has been developed which can safely and efficiently carry out grinding tasks in hostile environments using remote control and automatic control. This robot system incorporates a new method for the measurement of grinding force, in which the grinding force is measured from a moment about the grinder head's center of gravity. The influence of inertial forces caused by translational motion is removed, so that high stability is achieved. Furthermore, this robot can change the grinder's orientation to follow the surface of an object automatically, and can also grind the surface of an object into a desired shape. The new robot is expected to be applied to various types of grinding work in hostile environments. (author).

Yoshimi, Takashi; Jinno, Makoto (Toshiba Corp., Kawasaki, Kanagawa (Japan). Research and Development Center); Abe, Akira

1991-07-01

227

Remote-controlled grinding robot system for repair work  

International Nuclear Information System (INIS)

A new teleoperated grinding robot has been developed which can safely and efficiently carry out grinding tasks in hostile environments using remote control and automatic control. This robot system incorporates a new method for the measurement of grinding force, in which the grinding force is measured from a moment about the grinder head's center of gravity. The influence of inertial forces caused by translational motion is removed, so that high stability is achieved. Furthermore, this robot can change the grinder's orientation to follow the surface of an object automatically, and can also grind the surface of an object into a desired shape. The new robot is expected to be applied to various types of grinding work in hostile environments. (author)

228

The effect of dry grinding on antigorite from Mulhacen, Spain  

OpenAIRE

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...

Drief, A.; Nieto, F.

1999-01-01

229

High coercivity induced by mechanical milling in cobalt ferrite powders  

OpenAIRE

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 500oC. 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 magnetizatio...

Ponce, A. S.; Chagas, E. F.; Prado, R. J.; Fernandes, C. H. M.; Terezo, A. J.; Baggio-saitovitch, E.

2013-01-01

230

Modeling recrystallization kinetics during strip rolling  

Energy Technology Data Exchange (ETDEWEB)

In order to simulate the microstructural evolution during hot strip rolling, double-hit compression tests have been carried out on plain carbon steels. Using the softening data obtained by these tests, mathematical models were developed to predict the overall kinetics of static recrystallization under roughing and finishing mill conditions. These models include the effects of deformation temperature, applied strain, strain rate and initial austenite grain size. Predictions based on these models are in reasonable agreement with the present experimental results.

Sun, W.P.; Hawbolt, E.B.; Meadowcroft, T.R. [Univ. of British Columbia, Vancouver (Canada). The Centre for Metallurgical Process Engineering

1995-01-01

231

Multi-stage FE simulation of hot ring rolling  

Science.gov (United States)

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.

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

2013-05-01

232

Corroborative study on maize quality, dry-milling and wet-milling properties of selected maize hybrids.  

Science.gov (United States)

A corroborative study was conducted on the maize quality properties of test weight, pycnometer density, tangential abrasive dehulling device (TADD), time-to-grind on the Stenvert hardness tester (SHT), 100-kernel weight, kernel size distribution, and proximate composition as well as maize dry- and wet-millability by six participating laboratories. Suggested operating procedures were given to compare their measurements and provide the variance structure within and between laboratories and hybrids. Partial correlation coefficient among maize quality properties varied among laboratories. The repeatability and reproducibility precision values were acceptably low for the physical quality tests, except for TADD and SHT time-to-grind measurements. The yields of dry- and wet-milled products and their correlation with maize quality properties were dependent on the collaborating laboratory. This paper highlights the importance of laboratory variation when considering which maize hybrids are best suited for dry-milling and wet-milling. PMID:18020414

Lee, Kyung-Min; Herrman, Timothy J; Rooney, Lloyd; Jackson, David S; Lingenfelser, Jane; Rausch, Kent D; McKinney, John; Iiams, Chris; Byrum, Linda; Hurburgh, Charles R; Johnson, Lawrence A; Fox, Steven R

2007-12-26

233

GEOMETRICAL CHARACTERIZATION OF MICRO END MILLING TOOLS  

DEFF Research Database (Denmark)

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.

Borsetto, Francesca; Bariani, Paolo

2004-01-01

234

Development of grinding robot. Kensaku robotto no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

The grinding robot was developed to be adapted to diverse shapes. This robot was composed of 6 axes which can make 3 dimensional grinding and adopted Motoman-K30S which can operate the gringing along with the signal receiving. Of the grinding head, fixed side of sliding mechaism is fitted to the robot wrist and the electronic grinder is fitted to the movable side to contact and pressurize the grinding wheel to surface to be ground. Since the correlation between ground amount per unit time and motor current exists for the electronic grinder, the grinding amount is retained constant by controlling the current to constant value through lowing the slide mechanism, even if the detected current becomes lower than the set value. Therfore, a special sensor is not necessary. When the grinding wheel wears, the grinder follows to the ground surface, so that the grinding can stably be controlled from light gringing to heavy grinding. Since following and driving part is light and moves linearly, the robot is followable at high speed. The main body of the robot on which the grinding head is mounted, is not required to add a special function to control itself, enabling cheaper delivery. 9 figs., 2 tabs.

Tazaki, Taketoshi; Yokoo, Takashi

1989-12-01

235

Experimental study of interfacial heat flux and surface temperature by inverse analysis with thermocouple (fully embedded) during hot steel strip rolling  

OpenAIRE

Knowledge of temperature distribution in the roll is fundamental aspect in cold rolling. An inverse analytical method has been previously developed to determine interfacial heat flux and surface temperature by measuring the temperature with a thermocouple (fully embedded) at only one point inside the roll. On this basis some pilot mill tests have been performed. The temperature sensor, the calibration procedure and rolling tests at different strip rolling conditions (5%, 10%, 15% and 20%) are...

Weisz-patrault, Daniel; Ehrlacher, Alain; Legrand, Nicolas; Labbe, Nathalie; Horsky, Jaroslav; Luks, Tomas

2012-01-01

236

Measurement of the wear rate of cast grinding balls using radioactive tracers  

International Nuclear Information System (INIS)

The wear rate of grinding balls used in ball mills is usually hard to determine under operational conditions and little is known-about the factors determining ball life. Radioactive tracers have been used successfully to mark cast steel balls to obtain information on their life under various operating conditions for comparison with balls of different type or composition. A batch of marked steel balls has been followed through a milling operation over several weeks and statistics on wear and loss of weight have been obtained. In the test runs cobalt-60 was added to the molten metal before casting and the balls were then observed in use at an iron mine. The radioactive batch was added to a ball mill with a normal charge of about 75 tons and the mill charge was sampled at weekly intervals to pick out active balls. These balls were inspected and weighed, and the wear rate has been calculated. This procedure has proved to be a practical way of investigating wear properties under plant operating conditions. (author)

237

Strip shape analysis in unsymmetrical rolling; Sayu hitaisho atsuen no keijo seigyo kaiseki  

Energy Technology Data Exchange (ETDEWEB)

Model for analyzing unsymmetrical rolling based on a matrix model is built for a 6-stage rolling mill (UC mill) known for its excellent performance in correcting unsymmetrical shapes. The shape controlling properties of the UC mill in unsymmetrical rolling are examined by use of this analysis model. An experiment of unsymmetrical rolling is conducted in which the differentiated loads and the intermediate roll shift are changed, and it is found that there is good agreement between the calculated values and the values obtained from the experiment and that this analysis model works accurately in the analysis of unsymmetrical rolling. There holds a linear relationship between the unsymmetrical component involving the plate edge and quarter section inlet side plate crown and the unsymmetrical component involving the outlet side plate shape, and the effect of the inlet side plate crown can be quantified. When the work roll diameter is large, the scope of unsymmetrical shape control application is small because the controlling properties of the unsymmetrical shape controlling means are alike. When the work roll diameter is small, however, the unsymmetrical shape may be effectively controlled because the controlling properties are greatly dependent on the combination of the unsymmetrical intermediate roll shift with differentiated loads or with the unsymmetrical intermediate roll bender. 5 refs., 14 figs., 4 tabs.

Aizawa, A.; Hara, K.; Nakamoto, K. [Nippon Seiko K.K., Tokyo (Japan)

1997-09-30

238

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

Science.gov (United States)

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.

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

2015-03-01

239

New profilable bond system for diamond and CBN grinding wheels  

Science.gov (United States)

Attempts to use diamond or CBN grinding wheels for full cut or deep cutting processes in the machining of hard materials, were initially limited to grinding wheels coated by electrodeposition. The tool body was provided with the required profile and the diamond or CBN coating was electrodeposited in accordance with known methods. Success could be achieved with these grinding wheels in certain cases. The greater projection of abrasive grit obtained with electrodeposited coatings as opposed to impregnated coatings was removed by subsequent profiling with diamond profile grinding wheels, so that accurate tolerances for workpieces could be achieved up to a certain limit. The grain wear of the engaged tools is uneven and commences in those areas that are subjected to the greatest load such as at the edges or the projected radii so that recoating usually becomes necessary when the coating has worn away at only one point. For all practical purposes this amounts to a new coating. Efforts were therefore directed towards adapting the conventional grinding technique, involving the crushing of a profile onto the wheel periphery with the aid of a crushing device mounted on a grinding machine, to diamond and CBN grinding wheels. A prerequisite for this was to develop a bonding material which could be profiled by crushing. This method opened up new possibilities, particularly for deep and full cut grinding.

Macina, R.

240

High-speed milling of light metals  

Directory of Open Access Journals (Sweden)

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.

F. Cus

2007-09-01

241

Evaluation of grinding methods for pellets preparation aiming at the analysis of plant materials by laser induced breakdown spectrometry.  

Science.gov (United States)

It has been demonstrated that laser induced breakdown spectrometry (LIBS) can be used as an alternative method for the determination of macro (P, K, Ca, Mg) and micronutrients (B, Fe, Cu, Mn, Zn) in pellets of plant materials. However, information is required regarding the sample preparation for plant analysis by LIBS. In this work, methods involving cryogenic grinding and planetary ball milling were evaluated for leaves comminution before pellets preparation. The particle sizes were associated to chemical sample properties such as fiber and cellulose contents, as well as to pellets porosity and density. The pellets were ablated at 30 different sites by applying 25 laser pulses per site (Nd:YAG@1064 nm, 5 ns, 10 Hz, 25J cm(-2)). The plasma emission collected by lenses was directed through an optical fiber towards a high resolution echelle spectrometer equipped with an ICCD. Delay time and integration time gate were fixed at 2.0 and 4.5 ?s, respectively. Experiments carried out with pellets of sugarcane, orange tree and soy leaves showed a significant effect of the plant species for choosing the most appropriate grinding conditions. By using ball milling with agate materials, 20 min grinding for orange tree and soy, and 60 min for sugarcane leaves led to particle size distributions generally lower than 75 ?m. Cryogenic grinding yielded similar particle size distributions after 10 min for orange tree, 20 min for soy and 30 min for sugarcane leaves. There was up to 50% emission signal enhancement on LIBS measurements for most elements by improving particle size distribution and consequently the pellet porosity. PMID:21872013

Gomes, Marcos da Silva; Santos, Dário; Nunes, Lidiane Cristina; de Carvalho, Gabriel Gustinelli Arantes; Leme, Flávio de Oliveira; Krug, Francisco José

2011-09-30

242

Model Predictive Control for an Industrial SAG Mill  

DEFF Research Database (Denmark)

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.

Ohan, Valeriu; Steinke, Florian

2012-01-01

243

Thermal modeling of grinding for process optimization and durability improvements  

Science.gov (United States)

Both thermal and mechanical aspects of the grinding process are investigated in detail in an effort to predict grinding induced residual stresses. An existing thermal model is used as a foundation for computing heat partitions and temperatures in surface grinding. By numerically processing data from IR temperature measurements of the grinding zone; characterizations are made of the grinding zone heat flux. It is concluded that the typical heat flux profile in the grinding zone is triangular in shape, supporting this often used assumption found in the literature. Further analyses of the computed heat flux profiles has revealed that actual grinding zone contact lengths exceed geometric contact lengths by an average of 57% for the cases considered. By integrating the resulting heat flux profiles; workpiece energy partitions are computed for several cases of dry conventional grinding of hardened steel. The average workpiece energy partition for the cases considered was 37%. In an effort to more accurately predict grinding zone temperatures and heat fluxes, refinements are made to the existing thermal model. These include consideration of contact length extensions due to local elastic deformations, variations of the assumed contact area ratio as a function of grinding process parameters, consideration of coolant latent heat of vaporization and its effect on heat transfer beyond the coolant boiling point, and incorporation of coolant-workpiece convective heat flux effects outside the grinding zone. The result of the model refinements accounting for contact length extensions and process-dependant contact area ratios is excellent agreement with IR temperature measurements over a wide range of grinding conditions. By accounting for latent heat of vaporization effects, grinding zone temperature profiles are shown to be capable of reproducing measured profiles found in the literature for cases on the verge of thermal surge conditions. Computed peak grinding zone temperatures for the aggressive grinding examples given are 30--50% lower than those computed using the existing thermal model formulation. By accounting for convective heat transfer effects outside the grinding zone, it is shown that while surface temperatures in the wake of the grinding zone may be significantly affected under highly convective conditions, computed residual stresses are less sensitive to such conditions. Numerical models are used to evaluate both thermally and mechanically induced stress fields in an elastic workpiece, while finite element modeling is used to evaluate residual stresses for workpieces with elastic-plastic material properties. Modeling of mechanical interactions at the local grit-workpiece length scale is used to create the often measured effect of compressive surface residual stress followed by a subsurface tensile peak. The model is shown to be capable of reproducing trends found in the literature of surface residual stresses which are compressive for low temperature grinding conditions, with surface stresses increasing linearly and becoming tensile with increasing temperatures. Further modifications to the finite element model are made to allow for transiently varying inputs for more complicated grinding processes of industrial components such as automotive cam lobes.

Hanna, Ihab M.

244

Rolling friction and bistability of rolling motion  

CERN Document Server

The rolling motion of a rigid cylinder on an inclined flat viscous surface is investigated and the nonlinear resistance force against rolling, $F_R(v)$, is derived. For small velocities $F_R(v)$ increases with velocity due to increasing deformation rate of the surface material. For larger velocity it decreases with velocity due to decreasing contact area between the rolling cylinder and the deformed surface. The cylinder is, moreover, subjected to a viscous drag force and stochastic fluctuations due to a surrounding medium (air). For this system, in a wide range of parameters we observe bistability of the rolling motion. Depending on the material parameters, increasing the noise level may lead to increasing or decreasing average velocity.

Pöschel, T; Brilliantov, N; Zaikin, A; Poeschel, Thorsten; Schwager, Thomas; Brilliantov, Nikolai; Zaikin, Alexei

2005-01-01

245

Grinding Characteristics of Reaction Bonded Silicon Carbide  

Directory of Open Access Journals (Sweden)

Full Text Available Surface topography, surface residual stress and bending strength of RBSiC ground using diamond wheel were studied. Grinding RBSiC is removed mainly by brittle fracture and lightly by ductile cutting. With the increase of down feed, surface roughness Ra increases. Burnishing with no down feed can improve the Ra in some way. With increasing down feed, the compressive residual stress decreases because of an inadequately cooling effect. Compare with the specimens grounded using 0.9 ?m/s, those using down feed of 1.35 ?m/s have worse surface quality. Considering both the processing efficiency and the surface quality, the optimum parameters are as follow: 0.9?m/s down feed, 2.1 r/min work table rotational speed and 1 min burnishing.

YAO Wang, ZHANG Yu-Min, HAN Jie-Cai, ZHOU Yu-Feng

2012-07-01

246

Grinding-induced homochirality in crystal growth  

Science.gov (United States)

When two enantiomeric chiral crystals are ground in the solution, one enantiomer dominates the other and eventually homochirality is accomplished. To elucidate this homochirality in crystal growth, we performed kinetic Monte Carlo (KMC) simulations of two models; an ARS model where achiral monomer A crystallizes in R or S type crystal clusters, and a RS model where chiral molecules R and S convert their chirality in a monomer state prior to the formation of conglomerate. KMC simulation of both models reproduces chiral symmetry breaking when crystal is grown under grinding. Time-evolution of the number densities of R and S molecules is well-explained by rate equations with antagonistic and cooperative nonlinear terms.

Saito, Yukio; Hyuga, Hiroyuki

2011-03-01

247

Performance of Metal Cutting on Endmills Manufactured by Cooling-Air and Minimum Quantity Lubrication Grinding  

Science.gov (United States)

Grinding fluids have been commonly used during the grinding of tools for their cooling and lubricating effect since the hard, robust materials used for cutting tools are difficult to grind. Grinding fluids help prevent a drop in hardness due to burning of the cutting edge and keep chipping to an absolute minimum. However, there is a heightened awareness of the need to improve the work environment and protect the global environment. Thus, the present study is aimed at applying dry grinding, cooling-air grinding, cooling-air grinding with minimum quantity lubrication (MQL), and oil-based fluid grinding to manufacturing actual endmills (HSS-Co). Cutting tests were performed by a vertical machining center. The results indicated that the lowest surface inclination values and longest tool life were obtained by cooling-air grinding with MQL. Thus, cooling-air grinding with MQL has been demonstrated to be at least as effective as oil-based fluid grinding.

Inoue, Shigeru; Aoyama, Tojiro

248

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)

249

Influence of planetary milling parameters on the properties of the activated silicon and aluminium nitride powders  

Energy Technology Data Exchange (ETDEWEB)

Mechanochemical processing of the silicon nitride based powders by high energy milling in a planetary mill is reported. The particle size distribution, specific surface area and their morphology after milling were studied after a period of a short (30 min) or long (up to 360 min) grinding. It has been shown that mechanochemical processing with the high energy led to the considerable destruction of the component crystal lattice apart from particles diminution, and moreover, to decomposition of the applied surfactant. As a result, significant agglomeration of powder particles occurred after the given milling time.

Pawlik, T; Sopicka-Lizer, M; Mikuskiewicz, M [Department of Materials Science, Silesian University of Technology, Krasinskiego 8. 40-019 Katowice (Poland); Wlodek, T, E-mail: tomasz.pawlik@polsl.pl, E-mail: malgorzata.sopicka-lizer@polsl.pl, E-mail: marta.mikuskiewicz@polsl.pl [Zetom, ks. Bp. Herberta Bednorza 17, Katowice (Poland)

2011-05-15

250

Influence of planetary milling parameters on the properties of the activated silicon and aluminium nitride powders  

International Nuclear Information System (INIS)

Mechanochemical processing of the silicon nitride based powders by high energy milling in a planetary mill is reported. The particle size distribution, specific surface area and their morphology after milling were studied after a period of a short (30 min) or long (up to 360 min) grinding. It has been shown that mechanochemical processing with the high energy led to the considerable destruction of the component crystal lattice apart from particles diminution, and moreover, to decomposition of the applied surfactant. As a result, significant agglomeration of powder particles occurred after the given milling time.

251

Acoustic emission monitoring of high speed grinding of silicon nitride  

Science.gov (United States)

Acoustic emission (AE) monitoring of a machining process offers real-time sensory input which could provide tool condition and part quality information that is critical to effective process control. However, the choice of sensor, its placement, and how to process the data and extract useful information are challenging application-specific questions which researchers must consider. Here we report an effort to resolve these questions for the case of high speed grinding of silicon nitride using an electroplated single-layered diamond wheel. A grinding experiment was conducted at a wheel speed of 149 m s-1 and continued until the end of the useful wheel life. AE signal data were then collected for each complete pass at given grinding times throughout the useful wheel life. We found that the amplitude of the AE signal monotonically increases with wheel wear, as do grinding forces and energy. Furthermore, the signal power contained in the AE signal proportionally increases with the associated grinding power, which suggests that the AE signal could provide quantitative information of wheel wear in high-speed grinding, and could also be used to determine when the grinding wheel needs replacement. PMID:10829737

Hwang; Whitenton; Hsu; Blessing; Evans

2000-03-01

252

A critical study of high efficiency deep grinding  

International Nuclear Information System (INIS)

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, Barkhausen Noise Amplitude (BNA) measurements, surface roughness and Vickers micro-hardness appraisal. It has been shown that the fundamentals of the HEDG process have been understood through experimental as well as theoretical means and that through the various thermal models used, grinding temperatures can be predicted to give more control over this dynamic process. The main contributions to knowledge are made up of a number of elements within the grinding environer of elements within the grinding environment, the most important being the demonstration of the HEDG effect, explanation of the phenomenon and the ability to model the process. It has also been shown that grinding is a dynamic process and factors such as wheel wear will result in a continuous change in the optimum grinding conditions for a given material and wheel combination. With the significance of these factors recognised, they can be accounted for within an industrial adaptive control scenario with the process engineer confident of a more efficient use of time and materials to produce a higher quality product at lower cost. (author)

253

Numerical analysis of small recessed silicon carbide grinding wheels  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Silicon carbide grinding wheels are tools used in manufacturing industry to form precision componentsand continue to be used to increase production rates due to their ability to remove high volumes of material athigh speeds. There is a demand to increase the speed of rotation of the grinding wheel in order to achieve highremoval rates. The increase in speed creates a situation where the grinding machine and the operator are subjectedto a possible catastrophic failure of the wheel due to the stresses generated in the coarse brittle structure of thevitrified grinding wheel. The study focused on building and analyzing computer models of grinding wheels withrecessed features spinning at different rotational speeds. By employing a computational approach, it was possibleto determine the maximum principal stresses in the wheel together with the location of the stresses. The geometryof vitrified wheels considered included a plain-sided rotating wheel and a recessed rotating wheel.Design/methodology/approach: The paper shows how stresses and factors of safety are calculated in order topredict the bursting speeds of small recessed SiC grinding wheels. The main methods used include finite elementanalysis and mechanical testing of abrasive materials. The approach of the paper is to integrate the use of numericalanalysis techniques and experimental techniques to predict the safe operating conditions of SiC abrasive products.Findings: Calculations were conducted to determine maximum stress in parallel-sided and recessed cup wheels.Relevant factors of safety and bursting speed were also calculated and compared with experimental data. Thepaper proves the usefulness and applicability of a method developed for taking account of stress concentrationsat the recess of small cup-shaped silicon carbide grinding wheels.Research limitations/implications: The paper is limited to analyzing small recessed SiC grinding wheels.Further work should focus on large recessed wheels and wheels made with different abrasive grains and bondingmaterials. The type of porosity distribution should also be investigated.Practical implications: The paper shows how numerical methods are used to design safe operating conditionsfor brittle grinding wheels. The methods used show that numerical techniques are suitable for calculating themeasures of safety that are an important consideration when designing high speed rotating grinding wheels thatcan be devastating if allowed to fail in service.Originality/value: The originality in the paper is revealed owing to the fact that fracture mechanics principlesare applied to the prediction of failure of rotating grinding wheels. The paper is of practical importance tomechanical designers who are responsible for the safe design of grinding wheels.

M.J. Jackson

2010-11-01

254

Cryogenic grinding technology for traditional Chinese herbal medicine  

Science.gov (United States)

The fundamental principle of cryogenic grinding (cryogrinding) for Chinese herbal medicine is similar to that of grinding methods for conventional materials, but the compositions are very complex, containing aromatics of high volatility, oils and fats, which are easily oxidized. Using liquid nitrogen or liquid air as the cryogen, all of these thermosensitive Chinese herbal medicines can be ground below their brittle temperature. The colour and other properties of the products of cryo-grinding will not be changed and the flavour and nutrition of the medicines will not be lost.

Li, Shimo; Ge, Shuangyan; Huang, Zhongping; Wang, Qun; Zhao, Haoping; Pan, Huaiyu

255

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

Energy Technology Data Exchange (ETDEWEB)

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.

Yamanaka, Shinya, E-mail: syama@mmm.muroran-it.ac.jp [Muroran Institute of Technology, College of Environmental Technology (Japan); Suzuma, Akifumi [Muroran Institute of Technology, Division of Applied Sciences (Japan); Fujimoto, Toshiyuki; Kuga, Yoshikazu [Muroran Institute of Technology, College of Environmental Technology (Japan)

2013-04-15

256

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

OpenAIRE

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 highe...

Kannan S; Baskar. N

2013-01-01

257

Fractional order and BICO disturbance observers for a run-of-mine ore milling circuit  

OpenAIRE

Grinding mill circuits are hard to control due to poor plant models, large external disturbances, uncertainties from internal couplings, and process variables that are difficult to measure. This paper proposes a novel fractional order disturbance observer (FO-DOB) for a run-of-mine (ROM) ore milling circuit. A fractional order low pass filter (Q-filer) is used in the DOB to offer an additional degree of freedom in tuning for set-point tracking performance and disturbance rejection performance...

Olivier, Laurentz E.; Craig, Ian K.; Chen, Y. Q.

2011-01-01

258

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

Science.gov (United States)

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.

Medling, S.; France, C.; Balaban, B.; Kozina, M.; Jiang, Y.; Bridges, F.; Carter, S. A.

2011-05-01

259

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

International Nuclear Information System (INIS)

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.

260

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2000-05-01

261

Model Predictive Control for an Industrial SAG Mill  

OpenAIRE

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 contr...

Ohan, Valeriu; Steinke, Florian; Metzger, Michael; Runkler, Thomas; Jørgensen, John Bagterp

2012-01-01

262

Annular Fuel Pellet Fabrication without Surface Grinding  

International Nuclear Information System (INIS)

In order to increase the power density of a Pressurized Water Reactor fuel assembly, a dual cooled annular fuel has been seriously considered as a favorable option. A configurationally inherent merit of an annular fuel such as an increased heat transfer area and a thin pellet thickness results in a lot of advantages from the point of a fuel safety and its economy. Annular pellet with precisely controlled diametric tolerance is an essential element to actualize the dual cooled fuel. An hour-glassing usually occurs in a sintered cylindrical PWR fuel pellet fabricated by a conventional double-acting press due to an inhomogeneous green density distribution in a powder compact. An inhomogeneous green density distribution in a powder compact is attributed to granule-granule frictions and granule to pressing mold wall frictions. Frictions result in an irregular pressing load distribution in a powder compact. Thus, a sintered pellet undergoes a centerless grinding process in order to secure diametric tolerance specifications. In the case of an annular pellet fabrication using a conventional double-acting press, the same hour-glass shape would probably occur. The green density gradient in a powder compact depends on the pressing direction and the amount of the sintering deformation is inversely proportional to the initial green density. In case of a double-acting pressing, the middle portion of the green pellet has a lower green density than those of the top and the bottom pory than those of the top and the bottom portions of the green pellet. However, the top or the bottom portion which is far from the acting punch surface has the lowest green density in a single-acting pressing. In the present study, we are trying to find a way to minimize the diametric tolerance of the sintered annular pellet without surface grinding. Annular compacting mold with inclined inner and outer surfaces was designed by considering a difference in the diametric changes depending on the pellet height during sintering. By using a compacting mold with inclined surfaces and a single-acting press, an annular pellet can be fabricated successfully with a tolerance of less than ± 13 ?m which is the diametric tolerance specification of a conventional PWR fuel pellet

263

Understanding of Ultrasonic Assisted Machining with Diamond Grinding Tool  

Directory of Open Access Journals (Sweden)

Full Text Available In this work, machining test was carried out in various machining conditions using ultrasonic vibration capable CNC machine. For work material, alumina ceramic (Al2O3 was used while for tool material diamond electroplated grinding wheel was used. To evaluate ultrasonic vibration effect, grinding test was performed with and without ultrasonic vibration in same machining condition. In ultrasonic mode, ultrasonic vibration of 20 kHz was generated by HSK 63 ultrasonic actuator. On the other hand, grinding forces were measured by KISTLER dynamometer. And an optimal sampling rate for grinding force measurement was obtained by a signal processing and frequency analysis. The surface roughness of the ceramic was also measured by using stylus type surface roughness instrument and atomic force microscope (AFM. Besides, the scanning electron microscope (SEM was used for observation of surface integrality.

Kyung-Hee Park

2013-12-01

264

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)

265

Teeth Grinding: Is Emotional Stability related to Bruxism?  

OpenAIRE

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...

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

2010-01-01

266

Critical review of Nanofluid Minimum Quantity Lubrication for Grinding application  

OpenAIRE

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...

Mr. Prashant J. Patil,; Patil, Dr Chandrakant R.

2014-01-01

267

Effect of attrition milling on the reaction sintering of silicon nitride  

Science.gov (United States)

Silicon powder was ground in a steel attrition mill under nitrogen. Air-exposed powder was compacted, prefired in helium, and reaction-sintered in nitrogen-4 v/o hydrogen. For longer grinding times, oxygen content, surface area and compactability of the powder increased; and both alpha/beta ratio and degree of nitridation during sintering increased. Iron content remained constant.

Herbell, T. P.; Glasgow, T. K.; Yeh, H. C.

1978-01-01

268

Grinding process monitoring based on electromechanical impedance measurements  

Science.gov (United States)

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.

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

2015-04-01

269

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

Directory of Open Access Journals (Sweden)

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.

M. Drobne

2014-10-01

270

Effect of high-pressure coolant Jet on grinding temperature, chip and surface roughness in grinding AISI-1040 Steel  

Directory of Open Access Journals (Sweden)

Full Text Available Grinding can be described as a multi-tooth metal cutting operation in which material is generally removed by shearing and ploughing in the form of micro sized chips by the abrasive grits of the grinding wheel. As a result, high temperature is produced in the grinding zone due to large negative rake and high cutting speed of the grinding wheel. Suitable cutting fluid is employed to reduce the temperature through cooling and lubrication in the cutting zone. As conventionally applied cutting fluid is unable to enter into the chip tool interface, the interface temperature is reduced to some extent. However, high-pressure coolant (HPC jet effectively reduces cutting zone temperature entering into chip tool interface maintaining a good surface integrity. The present work investigates the role of high-pressure coolant jet on chip formation, grinding zone temperature and surface roughness in grinding AISI-1040 steel. The experimental results indicate significant reduction in cutting temperature on application of high-pressure coolant, which enables favorable chip formation and a better surface integrity for the finished work piece.

A.T. Siddiqui

2006-12-01

271

Quadropol RD. The world's first vertical roller mill with driven rollers; Quadropol RD. Weltweit erste Vertikalrollenmuehle mit angetriebenen Rollen  

Energy Technology Data Exchange (ETDEWEB)

The cement industry increasingly requires energy-efficient grinding systems for the production of ultra-fine cements. The vertical mill with driven rollers meets this requirement thanks to the innovative design of its drive system. Although no CO{sub 2} emissions are released in the mill itself, the mill contributes to reducing specific CO{sub 2} emissions in the production of ultra-fine composite cements. (orig.)

Schmitz, Thomas [ThyssenKrupp Resource Technologies GmbH, Neubeckum (Germany). Enginering Cement Production; Berger, Markus [ThyssenKrupp Resource Technologies GmbH, Neubeckum (Germany). R and D Automation; Fornefeld, Heiko [ThyssenKrupp Resource Technologies GmbH, Neubeckum (Germany). Engineering Design Roller Mills; Kimmeyer, Ludger [ThyssenKrupp Resource Technologies GmbH, Neubeckum (Germany). R and D Communication Technology

2013-11-01

272

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

International Nuclear Information System (INIS)

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

273

Effect of calcination temperature of yttrium oxalate on grinding, pressability and sintering of Y2O3  

International Nuclear Information System (INIS)

The effect of the yttrium oxalate calcination temperature on the press ability and sintering of Y2O3 has been studied. After roasting at 1650 dec C the most dense are the samples of Y2O3 produced by the pyrolysis of yttrium oxalate at 800 to 900 deg C. After roasting at 1750 deg C the sample density practically does not depend on the yttrium oxalate calcination temperature (within a certain region) or on the method of Y2O3 grinding. Using a half-dry pressing method at comparatively low pressures it is possible to manufacture products of Y2O3 produced by calcination of yttrium oxalate either at temperatures of 1000 to 1200 dec C without a subsequent crushing, or at temperatures of 1100 to 1400 dec C with a consecutive dry grinding in a planetary mill, and roast them at 1750 deg C. The shrinkage in these cases makes up: for the samples of calcinated and solid powder approximately 19%, for those of calcinated and crushed in a planetary mill - approximately 12 to 13%

274

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

Science.gov (United States)

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

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

2009-01-01

275

CISM Course on Rolling Contact Phenomena  

CERN Document Server

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

Kalker, Joost

2000-01-01

276

Validation of the Hot Strip Mill Model  

Energy Technology Data Exchange (ETDEWEB)

The Hot Strip Mill Model (HSMM) is an off-line, PC based software originally developed by the University of British Columbia (UBC) and the National Institute of Standards and Technology (NIST) under the AISI/DOE Advanced Process Control Program. The HSMM was developed to predict the temperatures, deformations, microstructure evolution and mechanical properties of steel strip or plate rolled in a hot mill. INTEG process group inc. undertook the current task of enhancing and validating the technology. With the support of 5 North American steel producers, INTEG process group tested and validated the model using actual operating data from the steel plants and enhanced the model to improve prediction results.

Richard Shulkosky; David Rosberg; Jerrud Chapman

2005-03-30

277

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2005-12-01

278

Real-time pressure monitoring for dynamic control during paper mill operation using fiber optic pressure sensors  

Science.gov (United States)

Fiber optic pressure sensors were integrated into the grinding plates of an operational paper pulp mill for real-time monitoring of the pulp grinding process. On-line system monitoring will allow smart, active control of the grinding plates thereby improving the quality and consistency of the pulp produced. Sensors were constructed and calibrated for use in the harsh environment of an operating paper pulp grinder. The sensors were 1.65mm in diameter including titanium housing, and were installed directly into the grooves of the grinding plates. The sensing elements were flush-mounted with the wall and exposed to the wood pulp slurry. Nine sensors were calibrated up to 1000psi. During operation, pressure was sampled at 1.0MHz, and pressure spikes up to 175psi were observed. Pressure pulses measured are due to the relative motion between the grooves and channels on two pulp grinding plates. The consistency, size distribution, and quality of paper pulp exiting from the grinder are directly related to the distance between the channels on the two rotating elements. The pressure pulses produced are also proportional to the distance between channels. Therefore, by monitoring pressure fluctuations, grinding elements can be dynamically controlled thereby producing a "smart mill."

Fielder, Robert S.; Boyd, Clark; Palmer, Matthew; Eriksen, Oddbjørn

2006-03-01

279

Long ball-milling of bcc-FeCr at different injected powers: Amorphization and partial crystallization  

International Nuclear Information System (INIS)

The structural changes induced by long ball-milling of the ?-FeCr bcc phase in vacuum in a vibratory Fritsch P0 mill at two different amplitudes, were studied by Moessbauer spectroscopy and X-ray diffraction. In previous studies we showed that amorphization is an intrinsic phenomenon which occurs when grinding alpha and sigma phases of near-equiatomic FeCr alloys. With long periods of milling at different injected powers, we observe a phenomenon of amorphization-partial crystallization-amorphization which is reminiscent of the cyclic amorphization-crystallization phenomenon that takes place in various ball-milled alloys.

280

Ultraprecision grinding of optical materials for high-power lasers  

Science.gov (United States)

Grinding is considered to be a rough machining process in the field of optics; a polishing process must follow the grinding process for getting optical-quality surfaces. An ultraprecision surface grinder with hydrostatic oil bearings and a glass-ceramic spindle of extremely low thermal expansion was developed to get smooth optical surfaces without any polishing process. Various optical materials such as NbF1, BK7, LHG08 fused silica, KTP, KDP and CLBO were ground into optical surfaces after empirically determining the conditions required to attain ductile-mode grinding. An extremely smooth surface less than 0.1 nm rms was obtained on BK7 glass by the ultraprecision grinding process. The laser-induced damage threshold was measured on variously finished LHG-8 laser glass at (lambda) equals 1.053 micrometers and 1-ns pulse width. The damage threshold was measured at 22.2 J/cm2 on a ground surface with the polarization parallel to the grinding direction. This number is higher than that obtained by optical polish. The damage threshold of 293 J/cm2 was also obtained on a ground LHG-8 glass surface at (lambda) equals 1.053 micrometers and 30-ns pulse width.

Namba, Yoshiharu; Yoshida, Kunio; Yoshida, Hidetsugu; Nakai, Sadao

1998-04-01

281

Grooved roll for a high speed twin roll caster  

Directory of Open Access Journals (Sweden)

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.

T. Haga

2008-04-01

282

Uranium metal oxidation, grinding, and encapsulation in BorobondR: TRU waste management - 59279  

International Nuclear Information System (INIS)

Hydrogen generation mitigation for K Basin sludge was examined by encapsulation of uranium metal in BoroBondR, pre-oxidation of uranium metal with Fenton's reagent and grinding of Densalloy SD170, an irradiated uranium metal surrogate. Encapsulation in BoroBondR resulted in pressure increase rates at 60 deg. C ranging from 0.116 torr/h to 0.186 torr/h compared to 0.240 torr/h for a uranium metal in water standard. Samples cast with higher water content led to increased rates. A Fenton's reagent system consisting of a simple reagent mix of FeSO4.7H2O, H2O2 and HCl effectively oxidized 1/4'' cubes of uranium metal in under four days at room temperature. Increased peroxide addition rate, increased FeSO4.7H2O concentration and low pH all increase the corrosion rate. Densalloy SD170 with an average particle size of 581 ?m with 7.63 % of particles less than 90 ?m was milled so that over 90 % of the Densalloy mass measured less than 90 ?m in 6 hours of milling. Acceptable wear rates were seen on wear components that were from standard materials (Nitronic SS and 440SS). (authors)

283

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

Directory of Open Access Journals (Sweden)

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.

Tong Junfeng

2013-04-01

284

Sensitivity of stress corrosion cracking of stainless steel to surface machining and grinding procedure  

International Nuclear Information System (INIS)

Highlights: ? Pits were more likely to be associated with surface defects induced by machining but tendency was not overwhelming. ? Stress corrosion cracks developed from pits, with cracks emerging both at the surface and within the pit. ? Stress corrosion cracking was attributed to a combination of high tensile residual stress and nanocrystalline layer. ? Stress corrosion cracking was also observed where net stress was compressive; a novel peeling stress effect is proposed. - Abstract: An investigation has been undertaken to establish the effect of surface preparation method on the susceptibility of a 304 stainless steel to stress corrosion cracking under simulated atmospheric corrosion conditions. MgCl2 was deposited onto four-point bend specimens, which were then placed in a chamber with a relative humidity of 45% and temperature of 60 deg. C. These test conditions were designed to reflect external exposure of stainless steel components in industrial plant, including nuclear reactor components, situated in a coastal region, but with the severity of the exposure conditions enhanced to allow discrimination of the effect of surface preparation in a short timescale (up to 1500 h). Four surface preparation methods were evaluated: transverse grinding, longitudinal grinding, transverse dressing using an abrasive flap wheel, and transverse milling. For each case, surface topography, surface defect mapping, near-surface microhardness mapping, residual stricrohardness mapping, residual stress and electron back-scattered diffraction measurements were undertaken. Stress corrosion cracks were observed for the ground and milled specimens but not for the dressed specimens, with cracks apparently originating at corrosion pits. The density of cracks increased in the order: transverse ground, milled and longitudinal ground, with the cracks notably much smaller in length for the transverse ground condition. The propensity for cracking could be linked to the high residual stress and apparent nanocrystalline microstructure at the surface. There was a greater propensity for pitting to initiate at local defect sites on the surface (laps, deeper grooves). However, the tendency was not overwhelming, suggesting that other factors such as more general roughness or the distribution of MnS inclusions had an influence, perhaps reflecting the severity of the environment.

285

In-process grinding monitoring through acoustic emission  

Directory of Open Access Journals (Sweden)

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.

Paulo R. Aguiar

2006-03-01

286

In-process grinding monitoring through acoustic emission  

Scientific Electronic Library Online (English)

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.

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

2006-03-01

287

Characterization of grinding wheels: An annotated Bibliography. Final report  

Energy Technology Data Exchange (ETDEWEB)

The characteristics of grinding wheels, after both fabrication and periods of operation, have a significant effect on the processed surface and the mechanical properties of advanced ceramics. An extensive literature survey and review has been conducted to determine and catalogue the various characterization methods that have been investigated and reported. Although many of the references have addressed the grinding of metals, the historical and technical merit justify their inclusion in this bibliography. For convenience, the references have been subdivided into nine subheadings: Nondestructive examination; elasticity and stiffness; wheel hardness; topography and profilometry; observation of texture of wheel surfaces wheel wear; in process monitoring of grinding, acoustic emission, other; characteristics of ground surfaces; and miscellaneous.

McClung, R.W.

1995-12-01

288

Methodology for automatic selection of passes in surface grinding  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The main purpose of this work is the development of computational tools in order to assist the on-line automatic detection of burn in the surface grinding process. Most of the parameters currently employed in the burning recognition (DPO, FKS, DPKS, DIFP, among others) do not incorporate routines fo [...] r automatic selection of the grinding passes, therefore, requiring the user’s interference for the choice of the active region. Several methods were employed in the passes extraction; however, those with the best results are presented in this article. Tests carried out in a surface-grinding machine have shown the success of the algorithms developed for pass extraction.

Fábio R. L., Dotto; Paulo Roberto de, Aguiar; Rogério, Thomazella; Eduardo Carlos, Bianchi.

2007-03-01

289

Quantitative control and optimization of grinding and polishing processes  

International Nuclear Information System (INIS)

The possibilities for the control and optimization of preparation processes and for the quantitative description of the quality of polished specimens are discussed using sintered aluminium oxide bodies as an example. A microscopic photometer and a TV image analyser were used in addition to the reflected light and scanning electron microscopes to control the grinding, lapping, and polishing processes. The photometer gave a very sensitive record of the nature of the surface from the grinding and lapping processes as well as from the first polishing step, whereas the fraction of regions that had not been levelled (pores and popouts) during polishing could be determined with an image analyser. Photographic documentation of the various stages of grinding, lapping, and polishing proved to be useful in selecting the most suitable method of preparation from the series of photographs. (orig.)

290

Single Grit Grinding Simulation by Using Finite Element Analysis  

Science.gov (United States)

In this research, basic material removal characteristics in a single grit grinding have been investigated by using Finite Element Analysis (FEA). ABAQUS/Standard is used as a computational environment. The influences of both friction and undeformed chip thickness are considered in the analyses of the grit ploughing, stress distribution and total force variation. Remeshing strategy is performed in the simulation to produce very fine meshes in the contact area to mitigate the material distortion due to large plastic deformation. The results show that the increase of undeformed chip thickness and frictional coefficient would increase ploughing action and grinding stress magnitude. Moreover, friction would cause the stress distribution circle on grit inclined backwards. Finally, FEM analysis can be considered as a strong tool for the single grit simulation of grinding process.

Öpöz, Tahsin Tecelli; Chen, Xun

2011-01-01

291

Shape-Grinding by Direct Position/Force Control  

Science.gov (United States)

Based on the analysis of the interaction between a manipulator's hand and a working object, a model representing the constrained dynamics of the robot is first discussed. The constrained forces are expressed by an algebraic function of states, input generalized forces, and the constraint condition, and then a direct position/force controller without force sensor is proposed based on the algebraic relation. To give a grinding system the ability to adapt to any object shape being changed by the grinding, we add a function estimating the constraint condition in real time for the adaptive position/force control. Evaluations through simulations, by fitting the changing constraint surface with spline functions, indicate that reliable position/force control and shape-grinding can be achieved by the proposed controller.

Chen, Guanghua; Xu, Weiwei; Minami, Mamoru

292

Roughness Generation In Precision Grinding Of Small Optical Surfaces  

Science.gov (United States)

Small steel moulds for injection moulding of polymer lenses are precision ground at Philips Research Laboratories. As part of a broader research program the relations between the process parameters and the generated surface roughness are investigated. A computer simulation technique used to investigate these relations is described. This technique allows us to investigate the effects of grinding wheel and workpiece geometries and of grain size, distribution and concentration. Process parameters such as depth of cut, infeed, and angular velocities can be chosen. The effects of initial workpiece roughness and of multiple passes of the grinding wheel over the surface can be investigated. Unbalance of the grinding wheel can also be taken into account. A simple geometrical model is used to calculate the shape of the scratches made by grains engaging the workpiece. The wear behaviour of grains can be taken into account assuming a simplified wear law. Some results of these simulations are presented. Predicted trends are compared with experimental results.

Franse, J.; de Jong, G. J.

1987-01-01

293

Potential release of carbon nanotubes from their composites during grinding  

Science.gov (United States)

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.

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

2013-04-01

294

High-speed, low-damage grinding of advanced ceramics Phase 1. Final report  

Energy Technology Data Exchange (ETDEWEB)

In manufacture of structural ceramic components, grinding costs can comprise up to 80% of the entire manufacturing cost. Most of these costs arise from the conventional multi-step grinding process with numerous grinding wheels and additional capital equipment, perishable dressing tools, and labor. In an attempt to reduce structural ceramic grinding costs, a feasibility investigation was undertaken to develop a single step, roughing-finishing process suitable for producing high-quality silicon nitride ceramic parts at high material removal rates at lower cost than traditional, multi-stage grinding. This feasibility study employed combined use of laboratory grinding tests, mathematical grinding models, and characterization of resultant material surface condition. More specifically, this Phase 1 final report provides a technical overview of High-Speed, Low-Damage (HSLD) ceramic grinding and the conditions necessary to achieve the small grain depths of cut necessary for low damage grinding while operating at relatively high material removal rates. Particular issues addressed include determining effects of wheel speed and material removal rate on resulting mode of material removal (ductile or brittle fracture), limiting grinding forces, calculation of approximate grinding zone temperatures developed during HSLD grinding, and developing the experimental systems necessary for determining HSLD grinding energy partition relationships. In addition, practical considerations for production utilization of the HSLD process are also discussed.

Kovach, J.A. [Eaton Corp., Willoughby Hills, OH (United States). Mfg. Technologies Center; Malkin, S. [Univ. of Massachusetts (United States)

1995-03-01

295

Performance analysis of magnesium phosphate cement mortar containing grinding dust  

Directory of Open Access Journals (Sweden)

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 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 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.

Daniel Véras Ribeiro

2009-03-01

296

Analysis of cement superplasticizers and grinding aids a literature survey  

Energy Technology Data Exchange (ETDEWEB)

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.)

Ervanne, H.; Hakanen, M. [Helsinki Univ. (Finland). Lab. of Radiochemistry

2007-04-15

297

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.)

298

Possibilities of Pelletizing and Briquetting of Dusts from Castings Grinding  

OpenAIRE

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 ...

Pribulova?, A.; Baricova?, D.; Futas?, P.; Gengel?, P.

2010-01-01

299

Dry recycling of grinding sludge in MOX fuel fabrication  

International Nuclear Information System (INIS)

Advanced Fuel Fabrication Facility (AFFF) is manufacturing MOX (U,Pu)O2 fuel on regular basis for TAPS reactor. Fuel pellet fabrication is done by powder metallurgy route involving cold compaction and sintering. In order to get diametrical specification the sintered pellets are centerless ground using diamond grind wheel in presence of liquid coolant which generates grinding sludge. The sludge contains uranium and plutonium with some amount of impurities. An attempt has been made to study recycling of this sludge (dirty reject oxide) by dry recycling route. This paper discusses the process developed at AFFF. (author)

300

Stability analysis of doubly regenerative cylindrical grinding process  

Science.gov (United States)

In this paper, we investigate the stability properties of a cylindrical grinding process. The dynamical model of the process includes two inherent delayed forcing terms, one from workpiece regeneration and the other from grinding wheel regeneration. The prediction of chatter onset is carried out by computing the spectrum of the doubly delayed differential equations for any set of physical and operational parameters. Stability diagrams are plotted in parameter space. The stability behavior obtained from this analysis is verified to be consistent with direct simulation results. A sensitivity analysis approach is also proposed, and can be used to lead an unstable process to a stable state by optimally varying one of the operational parameters.

Liu, Zhaoheng; Payre, Guy

2007-04-01

301

Analysis of fine-grinding techniques in terms of achievable surface qualities  

Science.gov (United States)

Shaping processes, e.g. cnc grinding, loose abrasive grinding and fluid jet polishing have been investigated experimentally for the level of sub-surface damage caused analyzing different process characteristics.

Fähnle, O.; Hauser, K.

2011-09-01

302

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

303

High coercivity induced by mechanical milling in cobalt ferrite powders  

Energy Technology Data Exchange (ETDEWEB)

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.

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

304

Temperature Prediction in High Speed Bone Grinding using Motor PWM Signal  

OpenAIRE

This research explores the feasibility of using motor electrical feedback to estimate temperature rise during a surgical bone grinding procedure. High-speed bone grinding is often used during skull base neurosurgery to remove cranial bone and approach skull base tumors through the nasal corridor. Grinding-induced heat could propagate and potentially injure surrounding nerves and arteries, and therefore, predicting the temperature in the grinding region would benefit neurosurgeons during the o...

Tai, Bruce L.; Zhang, Lihui; Wang, Anthony C.; Sullivan, Stephen; Wang, Guangjun; Shih, Albert J.

2013-01-01

305

Real-Time Simulation of Robot Controlled Belt Grinding Processes of Sculptured Surfaces  

OpenAIRE

Industrial robots are introduced to belt grinding processes of free-formed surface with elastic wheel nowadays in order to obtain high quality product and high efficiency. However, it is a laborious task to plan grinding paths and write programs for the robot. To release people from it partially, it is necessary to simulate the belt grinding processes which are useful for path generating and dynamic robot control. In this paper, we present a framework of the robot controlled belt grinding sim...

Malik Cabaravdic; Xiang Zhang; Klaus Kneupner; Bernd Kuhlenkoetter

2008-01-01

306

Calculation and Analysis of Temperature Distribution in Hot Rolling Strip  

OpenAIRE

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...

Kaixiang Peng

2013-01-01

307

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

308

Ship Roll Damping Control  

DEFF Research Database (Denmark)

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 difficulties associated with control system designs, which have proven to be far from trivial due to fundamental performance limitations and large variations of the spectral characteristics of wave-induced roll motion. This tutorial paper presents an account of the development of various ship roll motion control systems together with the challenges associated with their design. It discusses the assessment of performance and the applicability of different mathematical models, and it surveys the control methods that have been implemented and validated with full scale experiments. The paper also presents an outlook on what are believed to be potential areas of research within this topic.

Perez, Tristan; Blanke, Mogens

2012-01-01

309

Fast-roll inflation  

CERN Document Server

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.

Motohashi, Hayato; Yokoyama, Jun'ichi

2014-01-01

310

Sliding and Rolling: The Physics of a Rolling Ball.  

Science.gov (United States)

Presents an approach that provides a simple and adequate procedure for introducing the concept of rolling friction. Discusses some aspects related to rolling motion that are the source of students' misconceptions. Presents several didactic suggestions. (JRH)

Hierrezuelo, J.; Carnero, C.

1995-01-01

311

Recovery of titanium values from titanium grinding swarf by electric furnace smelting  

Science.gov (United States)

A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

Gerdemann, Stephen J. (Albany, OR); White, Jack C. (Albany, OR)

1999-01-01

312

Research of the residual stress in grinding surface of glass-ceramics  

Science.gov (United States)

We simulated the process of grinding glass-ceramics with the finite element simulation method. During the simulation, we considered the impact of changes in various process parameters on the grinding and analysis the simulation results of the residual stress at last. The target of this research is to provide some basic reference for the choice of the glass-ceramics grinding process parameters.

Zhou, Peng; Guo, Peiji

2014-08-01

313

Computer numerical control grinding of spiral bevel gears  

Science.gov (United States)

The development of Computer Numerical Control (CNC) spiral bevel gear grinding has paved the way for major improvement in the production of precision spiral bevel gears. The object of the program was to decrease the setup, maintenance of setup, and pattern development time by 50 percent of the time required on conventional spiral bevel gear grinders. Details of the process are explained.

Scott, H. Wayne

1991-01-01

314

The Graduate Grind: A Critical Look at Graduate Education  

Directory of Open Access Journals (Sweden)

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.

Annabelle L. Grundy

2003-07-01

315

Automatic programming of grinding robot restoration of contours  

OpenAIRE

A new programming method has been developed for grinding robots. Instead of using the conventional jog-and-teach method, the workpiece contour is automatically tracked by the robot. During the tracking, the robot position is stored in the robot control system every 8th millisecond. After filtering and reducing this contour data, a robot program is automatically generated.

Are Willersrud; Fred Godtliebsen; Trygve Thomessen

1995-01-01

316

Automatic programming of grinding robot restoration of contours  

Directory of Open Access Journals (Sweden)

Full Text Available A new programming method has been developed for grinding robots. Instead of using the conventional jog-and-teach method, the workpiece contour is automatically tracked by the robot. During the tracking, the robot position is stored in the robot control system every 8th millisecond. After filtering and reducing this contour data, a robot program is automatically generated.

Are Willersrud

1995-07-01

317

Flow Stress Evaluation in Hot Rolling of Steel  

Science.gov (United States)

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.

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

2014-08-01

318

Ship Roll Motion Control  

DEFF Research Database (Denmark)

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.

Perez, Tristan University of Newcastle

2010-01-01

319

Slitting criterion for various rolling speeds in MSR rolling process  

Directory of Open Access Journals (Sweden)

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.

A. Stefanik

2008-03-01

320

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

321

Analytical inverse solution for coupled thermoelastic problem for the evaluation of contact stress during steel strip rolling  

OpenAIRE

Knowledge of the contact stress between roll and strip is a critical factor in modern, high-speed rolling mills. Previously two inverse analytical methods have been developed to determine the elastic contact stress on the one hand and the heat flux or the temperature in the whole roll (and especially at the surface) on the other hand, by measuring the stress tensor inside the roll body with fibre optics and by measuring the temperature with a thermocouple fully embedded at only one point insi...

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

2013-01-01

322

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)

323

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

DEFF Research Database (Denmark)

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.

Laugier, Maxime; Boman, Romain

2014-01-01

324

Development of ELID mirror surface grinding by cast iron bond grinding wheel. Ohkochi memorial technology prize; Chutetsu bond toishi ni yoru denkai inpurosesu doresshingu (ELID) kyomen kensakuho no kaihatsu. Okochi kinen gijutsusho jusho ni yosete  

Energy Technology Data Exchange (ETDEWEB)

Development was accomplished on the electrolytic in-process dressing (ELID) mirror surface grinding process using a cast iron bonded grinding wheel. This paper describes the history of the development, which may be summarized as follows: a study was begun on powder forging of cutting chips in 1970; a research was started on powder forging of decarburized cast iron powder; developments were made on powder metallurgy of cast irons and cast iron bonded lapping tools in 1980, and cast iron bonded diamond grinding wheels were put on the market; a high-efficiency grinding process using MC and cast iron fiber-bonded grinding wheels were developed in 1985 and the grinding wheels made therefrom were put on the market; and a study was begun on the ELID grinding in 1987, and marketing was started on power supply, grinding liquid and tools for the ELID grinding process in 1990. Discussions on converting raw materials for the powder forging into cutting chips have triggered developing the cast iron bonded grinding wheel. The cast iron bonded diamond grinding wheel improves dressability and sharpness of conventional grinding wheels. The grinding wheel is fabricated by mixing carbonyl iron powder, diamond grinding grains and cast iron powder, pressing the mixture in a die, sintering it at 1140 degC, and assembling and dressing the sinter. The grinding stone can grind high-tech materials. 4 figs.

Omori, H.; Takahashi, I. [Institute of Physical and Chemical Research, Tokyo (Japan); Nakagawa, T. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science; Hagiuda, Y.; Karikome, K. [Tokyo Metropolitan College of Aeronautical Engineering, Tokyo (Japan)

1997-08-01

325

Cryogenic Grinding: a Physical Technique to Retain Volatile Content in Natural Products  

Science.gov (United States)

Cryogenics is the study of the production of very low temperature (below -150°C, -238°F or 123K) and the behavior of materials at those temperatures. Similarly, cryogenic grinding is a term supported by the act of grinding a thing at very low temperature. This technique is generally used to grind the material, which contains heat labile constituents viz- volatile oils in seed spices. Due to high fat content in spices, heat is generated, while energy is used to fracture a particle into a smaller size in conventional grinding process. During the normal grinding process, this generated heat causes temperature rise of grinder upto 950C. The increased temperature is responsible for a loss of volatile content in the tune of about 30% and also produces dark colour powder. Generally, continuous operation is not possible in normal grinding process due to melting of fat and sticking of powder on the grinding surface. The loss of volatile content can be significantly reduced by cryogenic grinding technique using liquid nitrogen or liquid carbon dioxide that provides the refrigeration needed to pre-cool the spices and maintain the desired low temperature by absorbing the heat generated during the grinding operation. The extremely low temperature during grinder condenses the volatile matter and retains their presence in spices. The application of cryogenic technology for grinding of spices has been scientifically proved to be a suitable technique with negligible loss of volatile content and improved colour of oil and grinding operation of seeds.

Saxena, Rohit; Soni, Aditi; Saxna, S. N.; Rathore, S. S.; Barnwal, P.

326

Grinding force model of single abrasive grain based on variable friction coefficient  

Science.gov (United States)

Combined with the grinding principle, it is put forward that friction coefficient changes with the change of grinding parameter; and the grinding force model of single abrasive grain is developed based on friction coefficients of different grinding conditions. Following the theory of variable friction coefficient, the grinding force model of single abrasive grain is theoretically and experimentally researched. The research indicates that this model fully reflects the effects of grinding parameter, abrasive grains' distribution, material properties, variable friction coefficient, and etc. on grinding force of single abrasive grain, which ensure an accurately simulation of actual grinding situation. By using this model, it is predicted that grinding force of single abrasive grain in normal direction has an accuracy of about 18~36.84%; however when taking the variable friction coefficient into consideration, prediction of tangential grinding force of single abrasive grain has an accuracy of about 10~20% by using this model. Experiment proves that this study offered a new grinding force model of single abrasive grain with variable friction coefficient, which has a practical value.

Kuai, Jicai; Zhang, Huali; Zhang, Feihu

2011-05-01

327

Development of a grinding-specific performance test set-up.  

Science.gov (United States)

The aim of this study was to develop a performance test set-up for America's Cup grinders. The test set-up had to mimic the on-boat grinding activity and be capable of collecting data for analysis and evaluation of grinding performance. This study included a literature-based analysis of grinding demands and a test protocol developed to accommodate the necessary physiological loads. This study resulted in a test protocol consisting of 10 intervals of 20 revolutions each interspersed with active resting periods of 50 s. The 20 revolutions are a combination of both forward and backward grinding and an exponentially rising resistance. A custom-made grinding ergometer was developed with computer-controlled resistance and capable of collecting data during the test. The data collected can be used to find measures of grinding performance such as peak power, time to complete and the decline in repeated grinding performance. PMID:25367077

Olesen, C G; Larsen, B H; Andresen, E L; de Zee, M

2015-04-01

328

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)

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].

Zhenhua Bai

2011-07-01

329

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

Directory of Open Access Journals (Sweden)

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.

Péricles Guedes Alves

2012-12-01

330

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

331

GRCop-84 Rolling Parameter Study  

Science.gov (United States)

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.

Loewenthal, William S.; Ellis, David L.

2008-01-01

332

Hot rolling of intermetallics FeAl phase based alloys  

Directory of Open Access Journals (Sweden)

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.

G. Niewielski

2008-02-01

333

Study of thresholds to burning in surface grinding process  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english This work aims at finding out the threshold to burning in surface grinding process. Acoustic emission and electric power signals are acquired from an analog-digital converter and processed through algorithms in order to generate a control signal to inform the operator or interrupt the process in the [...] case of burning occurrence. The thresholds that dictate the situation of burn and non-burn were studied as well as a comparison between the two parameters was carried out. In the experimental work one type of steel (ABNT-1045 annealed) and one type of grinding wheel referred to as TARGA model 3TG80.3 - NV were employed.

P. R. de, Aguiar; F. R. L., Dotto; E. C., Bianchi.

2005-06-01

334

New Method of Controlling Grinding Accuracy with Dynamic Compensatory  

Science.gov (United States)

Based on time series analysis, the control technique of grinding accuracy with dynamic compensatory is proposed. In the new technique, the optimal spectrum measurement technique is used as the on-line high precision measurement of the stochastic motion error of the worktable on the guide-way grinder. Then, the mathematics model for the stochastic motion error is given here. The stochastic motion error is predicted by the adaptive predictor, and Kalman filter is used to improve the predicting accuracy. By defining a compensatory curve, real-time compensatory control is adopted to realize high grinding precision on the guide-way grinder. The results from experiments of actual measurement and system simulation show the new technique is effective.

Xu, Huibin; Tao, Jianwu; Gao, Xiang

335

Walk and roll robot  

Science.gov (United States)

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.

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

2011-01-01

336

Variability in Hand-Arm Vibration During Grinding Operations  

OpenAIRE

Background: Measurements of exposure to vibrations from hand-held tools are often conducted on a single occasion. However, repeated measurements may be crucial for estimating the actual dose with good precision. In addition, knowledge of determinants of exposure could be used to improve working conditions. The aim of this study was to assess hand–arm vibration (HAV) exposure during different grinding operations, in order to obtain estimates of the variance components and to evaluate the eff...

Liljelind, Ingrid; Wahlstro?m, Jens; Nilsson, Leif; Toomingas, Allan; Burstro?m, Lage

2011-01-01

337

Synthesis by reactive grinding of molybdenum iron bimetallic nitride  

International Nuclear Information System (INIS)

The transition metal nitride ternary show similar properties to the binary nitride and some times this behaviour are improved. In the present work, the molybdenum-iron nitride has been prepared by reactive grinding form the two metals under nitrogen atmosphere at a pressure of 11 bar. The characterization of the compounds is presented and it is also shown a study of the stability of the nitride under several atmospheres. (Author) 42 refs

338

A Novel and More Efficient Way to Grind Punching Tools  

OpenAIRE

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...

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

2011-01-01

339

Force Controlled Knife-Grinding with Industrial Robot  

OpenAIRE

This paper investigates the application of sharpening knives using a force controlled industrial robot, for an arbitrary knife shape and orientation. The problem is divided into different parts: calibration of the knife by identifying its unknown orientation, identification of the knife blade contour and estimation of its position in the robot frame through force control, and grinding of the knife, following the path defined by the earlier identified shape, while applying the desired contact ...

So?rnmo, Olof; Robertsson, Anders; Wanner, Anders

2012-01-01

340

FRACTURE FEATURES OF METAL BINDING WHEN DIAMOND-SPARK GRINDING  

Directory of Open Access Journals (Sweden)

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

Yury GUTSALENKO

2012-05-01

341

Cooking and grinding reduces the cost of meat digestion.  

Science.gov (United States)

The cooking of food is hypothesized to have played a major role in human evolution partly by providing an increase in net energy gain. For meat, cooking compromises the structural integrity of the tissue by gelatinizing the collagen. Hence, cooked meat should take less effort to digest compared to raw meat. Likewise, less energy would be expended digesting ground meat compared to intact meat. We tested these hypotheses by assessing how the cooking and/or grinding of meat influences the energy expended on its digestion, absorption, and assimilation (i.e., specific dynamic action, SDA) using the Burmese python, Python molurus. Pythons were fed one of four experimental diets each weighing 25% of the snake's body mass: intact raw beef, intact cooked beef, ground raw beef, and ground cooked beef. We measured oxygen consumption rates of snakes prior to and up to 14 days following feeding and calculated SDA from the extra oxygen consumed above standard metabolic rate. Postprandial peak in oxygen consumption, the scope of peak rates, and SDA varied significantly among meal treatments. Pythons digesting raw or intact meals exhibited significantly larger postprandial metabolic responses than snakes digesting the cooked ground meals. We found cooking to decrease SDA by 12.7%, grinding to decrease SDA by 12.4%, and the combination of the two (cooking and grinding) to have an additive effect, decreasing SDA by 23.4%. These results support the hypothesis that the consumption of cooked meat provides an energetic benefit over the consumption of raw meat. PMID:17827047

Boback, Scott M; Cox, Christian L; Ott, Brian D; Carmody, Rachel; Wrangham, Richard W; Secor, Stephen M

2007-11-01

342

Can seeds help mice with the daily grind?  

Science.gov (United States)

Some laboratory mice gnaw food pellets without ingesting much of the gnawed material, resulting in the production of waste material called 'orts'. The fact that this food grinding behavior is not seen in all individuals of a particular strain suggests that it might be abnormal, and thus indicate a welfare concern. Furthermore, the increased rate of feed consumption and cage soiling is undesirable from a husbandry perspective. To try to determine possible motivations for the behavior, and identify potential treatments, outbred Crl:CD1(Icr) mice exhibiting food grinding were selected for one of three treatments placed in the feeder: no enrichment, a chewing device, or sunflower seeds. Both enrichment groups showed a significant decrease (P food wastage after the treatment was withdrawn. A relationship between body weight and ort production was also found, in that cages with greater average body weights had lower levels of ort production. This suggests that a simple need to gnaw cannot alone explain food grinding, and that a nutritional motivation may also be involved. PMID:23760566

Pritchett-Corning, K R; Keefe, R; Garner, J P; Gaskill, B N

2013-10-01

343

Multivariable control of grinding plants: a comparative simulation study.  

Science.gov (United States)

In this paper five multivariable adaptive and classical control strategies have been studied and implemented in a simulator of the copper grinding plant of CODELCO-Andina. The strategies presented were compared and, according to theory, exhibit good behavior. The extended horizon, pole-placement and model reference multivariable adaptive control strategies were formulated in discrete-time and use a model of the plant whose parameters are updated on line using the recursive least squares method along with UD factorization of the covariance matrix and variable forgetting factor. The direct Nyquist array and sequential loop closing techniques were also studied and simulated. The two-by-two multivariable system chosen to represent the grinding plant has the percentage of solids (density) of the pulp fed to the hydrocyclones (which is highly correlated with the percentage of +65 mesh in the overflow of hydrocyclones) and the sump level as output (controlled) variables. The water flow added to the sump and the speed of the pump are its input (manipulated) variables. All the algorithms tested by simulation exhibited good performance and were able to control the grinding plant in a stable fashion. Adaptive algorithms showed better performance than classical techniques, with the extended horizon and pole-placement algorithms proving to be the best. The fact that adaptive algorithms continuously adjust their parameters renders such controllers superior to those based on fixed parameters. PMID:12014804

Duarte, Manuel; Castillo, Alejandro; Sepúlveda, Florencio; Contreras, Angel; Giménez, Patricio; Castelli, Luis

2002-01-01

344

Physical characterization of coffee after roasting and grinding  

Directory of Open Access Journals (Sweden)

Full Text Available Flowability is an important characteristic of handling process for efficiency and reliability purpose of post-harvest operations, which are governed by the physical properties of the product. Physical properties determination is an important factor for formulation of machinery projects and sizing of post-harvest operations, which may impact considerably on the products quality, influencing directly the operation cost and company profit. Thus, the objective of this work was to evaluate and determinate some physical properties (repose angle, unit and bulk density, porosity and color coordinates, particle size, moisture content, water activity, angle of internal friction and effective angle of internal friction of coffee, such as to evaluate the influence of different roast and grinding degrees over these properties. Crude grain coffee (Coffea canephora and Coffea arabica, dehulled and dried were used. These were roasted at two levels: medium light and medium-dark brown, which Agtron numbers are, respectively, SCAA#65 and SCAA#45. After roasting process, grains were grinded at three particle sizes (thin, medium and thick. Both particle size and roast degree significantly affected physical properties of coffee. Coffee samples roasted at medium dark level obtained lower values of moisture content, water activity, repose angle, bulk and real density. Coffee samples grinded at level thin presented an increase of angle of internal friction and effective angle of internal friction, repose angle, bulk and real density, porosity and decrease of water activity values.

Gabriel Henrique Horta de Oliveira

2014-09-01

345

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...

346

Subsurface damage mechanism of high speed grinding process in single crystal silicon revealed by atomistic simulations  

Science.gov (United States)

Three-dimensional molecular dynamics (MD) simulations are performed to investigate the nanoscale grinding process of single crystal silicon using diamond tool. The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation are studied. We also establish an analytical model to calculate several important stress fields including hydrostatic stress and von Mises stress for studying subsurface damage mechanism, and obtain the dislocation density on the grinding subsurface. The results show that a higher grinding velocity in machining brittle material silicon causes a larger chip and a higher temperature, and reduces subsurface damage. However, when grinding velocity is above 180 m s-1, subsurface damage thickness slightly increases because a higher grinding speed leads to the increase in grinding force and temperature, which accelerate dislocation nucleation and motion. Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle, that provides valuable reference for machining nanometer devices. The von Mises stress and the hydrostatic stress play an important role in the grinding process, and explain the subsurface damage though dislocation mechanism under high stress status. The dislocation nucleation and motion induced plastic deformation during grinding process can better reveal subsurface damage mechanism considering to stress and temperature acting on the dislocations.

Li, Jia; Fang, Qihong; Zhang, Liangchi; Liu, Youwen

2015-01-01

347

Development and investigation of industrial technique for hot rolling of small cross section rods of unyielding heat resisting alloys  

International Nuclear Information System (INIS)

A hot-rolling technology has been developed for rolling rods about 14 to 16 mm in diameter made of EI826, EI929VD, EI867VD heat-resistant nickel alloys, the rods being used for manufacturing the fastening parts and for die-forging blades. The blanks preheated up to a temperature of 1160 to 1190 deg C are rolled on ''300/450'' rolling mill in two processes according to two roll pass designs; namely, oval-round for rolling the rods 16 mm in diameter, and square-oval-round for the rods 14 mm in diameter. It is the installation of the technology of manufacturing rods of decreased diameters from the above heat-resistant alloys that yields a considerable economical effect, owing to the saving of up to 40% of an expensive metal and to the reducing of the amount of work as required for manufacturing the machine parts

348

Studying possibilities to improve the functional properties of metallurgical rolls  

Directory of Open Access Journals (Sweden)

Full Text Available 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 tribologicnl propcnics through adji~stmcno~r ~ h cch cinicalcompsizion odand modificat ioll of rhc hcat trcatmcnt. In thc study prcscntcd only t hc carbon comcnt was sliyhtly incrcascd (havingciirhiclc-forming clcmcnts in Y icw rcst~ltingi n thc incrcnse in lcdcburitic carbides. Il owcvcr, !his most nhvious way or improving thcahrasivc wcar rcsisrnncc incrcascs rhc ~brcaot f rolls cracking and ~hcrcforcrc quircs verification using ttlc iracii~rc~ ncchanicsm cthod.Szaziaical analysis of random1 y sclcctcd fcw dozens of rolls havc shown Tor this gradc or cast stccl a trcnd to rcducc thc carbon contcnzby ~ h ~cn :~nurihcturcmr. ilintilining ir at thc lowcr rangc of limirs spccificd by thc standard and not to incrcasc i t . Thc analysis or thc wcnrmcchmism or suriaccs or worn out mlls madc of G2OOCrMoNi 4-3-3 cast stecl allows making suggestions on thc possihilit ics of hcatrrcarmcnt changes, what aEso has hccn prcscnrcd in ~ h pc a p .

Z. Stradomski

2008-03-01

349

Ground versus steam-rolled barley grain for lactating cows: a clarification into conventional beliefs.  

Science.gov (United States)

Our objective was to compare the effects of grinding versus steam-rolling of barley grain at 30 or 35% of diet dry matter on feed intake, chewing behavior, rumen fermentation, and milk production in high-producing lactating cows. Eight multiparous Holstein cows (85 +/- 9 d in milk) were used in a replicated 4 x 4 Latin square design experiment with four 21-d periods. Each period included 14 d of adaptation and 7 d of sampling. Treatments included grinding (GB) or steam-rolling (SB) of barley grains at either 35 or 30% of dietary dry matter. Diets were prepared as a total mixed ration and delivered twice daily at 0730 and 1600 h. Neither processing method nor dietary barley grain inclusion rate affected dry matter intake, daily eating, ruminating and chewing times, rumen pH and major volatile fatty acid molar percentages, or milk percentages and yields of fat and protein. Energy-corrected milk yield increased for SB compared with GB at 35% but not at 30% barley grain. Feed efficiency was increased by SB, but was unaffected by dietary barley grain level. Results suggest that at 30% dietary barley grain, GB resulted in similar lactation performance as SB and that SB did not affect productivity when dietary barley grain increased from 30 to 35%. Regardless of barley grain level, grinding effectively maintained dry matter intake and rumen pH at 4 h postfeeding, whereas steam-rolling increased feed efficiency. Increasing barley grain from 30 to 35% of diet dry matter did not improve feed intake and milk production. PMID:19528607

Soltani, A; Ghorbani, G R; Alikhani, M; Samie, A; Nikkhah, A

2009-07-01

350

Speed roll laws influence in a Ring Rolling process  

OpenAIRE

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...

Giorleo, Luca; Ceretti, Elisabetta; Giardini, Claudio

2013-01-01

351

Grooved roll for a high speed twin roll caster  

OpenAIRE

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 ...

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

2008-01-01

352

Cylindrical grinding of SiC particles reinforced aluminium metal matrix composites  

Directory of Open Access Journals (Sweden)

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.

C. Thiagarajan

2011-01-01

353

G-MG Toilet Roll  

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: Picture a roll of toilet paper; assume that the paper in the roll is very tightly rolled. Assuming that the paper in the roll is very thin, find a rela...

354

Rolling cuff flexible bellows  

Science.gov (United States)

A flexible connector apparatus used to join two stiff non-deformable members, such as piping. The apparatus is provided with one or more flexible sections or assemblies each utilizing a bellows of a rolling cuff type connected between two ridge members, with the bellows being supported by a back-up ring, such that only the curved end sections of the bellows are unsupported. Thus, the bellows can be considered as being of a tube-shaped configuration and thus have high pressure resistance. The components of the flexible apparatus are sealed or welded one to another such that it is fluid tight.

Lambert, Donald R. (Livermore, CA)

1985-01-01

355

Strength and power determinants of grinding performance in America's Cup sailors.  

Science.gov (United States)

The purpose grinding is a physically demanding component of America's Cup sailing that is important to overall team performance, but little research is available on the determinants of grinding performance. We examined the relationship between various measures of muscular performance and the performance of upper-body grinding. Eleven elite male America's Cup sailors (33.9 +/- 5.5 yr, 97.8 +/- 12.5 kg, 186.0 +/- 7.1 cm) who performed grinding as part of their on-board role with extensive strength training experience participated in this study. Muscular performance testing examined the force, velocity, and power capabilities of the upper-body musculature, with upper-body push (bench press) and pull (bench pull) movements performed across loads of 10-100% of 1 repetition maximum (1RM). Functional grinding performance was examined for both forward and backward grinding and at 2 different resistances (moderate = 48 N x m, heavy = 68 N x m) using a land-based ergometer. Bench press 1RM and maximum force capability were the measures demonstrating the strongest correlation with forward grinding performance (r = 0.88-0.99 and 0.87-0.99, respectively), with the relationship increasing with grinding load. For backward grinding, there was a very strong relationship with bench pull maximum power (r = 0.85-0.98) in addition to 1RM (r = 0.90-0.95) and maximum force (r = 0.87-0.95). It appears that although maximal strength is a crucial muscular performance characteristic for grinding performance in all conditions, for backward grinding, there is the additional need to focus on the development of speed strength/power to maximize performance gains. This information was used by the Emirates Team New Zealand physical conditioner to develop a conditioning intervention to help improve grinding performance. PMID:19675468

Pearson, Simon N; Hume, Patria A; Cronin, John B; Slyfield, David

2009-09-01

356

Investigation of the Formation Process of Two Piracetam Cocrystals during Grinding  

OpenAIRE

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 ...

Keith Gordon; Thomas Rades; Leopold, Claudia S.; Strachan, Clare J.; Marten Klukkert; Albrecht Sakmann; Lo?bmann, Korbinian A. M.; Sönke Rehder

2011-01-01

357

Cylindrical grinding of SiC particles reinforced aluminium metal matrix composites  

OpenAIRE

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, experimen...

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

2011-01-01

358

Production of nanocrystalline powders by high-energy ball milling: model and experiment.  

Science.gov (United States)

A model of high-energy ball milling of powders has been proposed. It is demonstrated that part of the energy is consumed for initiation of microstrains ? during milling and, hence, the process of the powder grinding is decelerated. An analytical expression has been deduced describing the size of nanocrystalline powder particles as a function of the milling time. The model and the experiment have been compared, using a powder of tungsten carbide (WC). The average size of the particles and the value of the microstrains in the ball-milled powder were determined by an x-ray method from broadening of diffraction reflections. The size of the particles was also evaluated using scanning electron microscopy and the sedimentation method. PMID:21828678

Gusev, A I; Kurlov, A S

2008-07-01

359

Production of nanocrystalline powders by high-energy ball milling: model and experiment  

Energy Technology Data Exchange (ETDEWEB)

A model of high-energy ball milling of powders has been proposed. It is demonstrated that part of the energy is consumed for initiation of microstrains {epsilon} during milling and, hence, the process of the powder grinding is decelerated. An analytical expression has been deduced describing the size of nanocrystalline powder particles as a function of the milling time. The model and the experiment have been compared, using a powder of tungsten carbide (WC). The average size of the particles and the value of the microstrains in the ball-milled powder were determined by an x-ray method from broadening of diffraction reflections. The size of the particles was also evaluated using scanning electron microscopy and the sedimentation method.

Gusev, A I; Kurlov, A S [Institute of Solid State Chemistry, Ural Division of the Russian Academy of Sciences, Ekaterinburg 620041 (Russian Federation)], E-mail: gusev@ihim.uran.ru

2008-07-02

360

Production of nanocrystalline powders by high-energy ball milling: model and experiment  

International Nuclear Information System (INIS)

A model of high-energy ball milling of powders has been proposed. It is demonstrated that part of the energy is consumed for initiation of microstrains ? during milling and, hence, the process of the powder grinding is decelerated. An analytical expression has been deduced describing the size of nanocrystalline powder particles as a function of the milling time. The model and the experiment have been compared, using a powder of tungsten carbide (WC). The average size of the particles and the value of the microstrains in the ball-milled powder were determined by an x-ray method from broadening of diffraction reflections. The size of the particles was also evaluated using scanning electron microscopy and the sedimentation method

361

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

Directory of Open Access Journals (Sweden)

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.

Hameedur Rehman Khan

2014-07-01

362

Imaging subsurface damage of grinded fused silica optics by confocal fluorescence microscopy  

Energy Technology Data Exchange (ETDEWEB)

We report an experimental investigation of fluorescence confocal microscopy as a tool to measure subsurface damage on grinded fused silica optics. Confocal fluorescence microscopy was performed with an excitation at the wavelength of 405 nm on fixed abrasive diamond grinded fused silica samples. We detail the measured fluorescence spectrums and compare them to those of oil based coolants and grinding slurries. We evidence that oil based coolant used in diamond grinding induces a fluorescence that marks the subsurface damages and eases its observation. Such residual traces might also be involved in the laser damage process. (authors)

Neauport, J.; Cormont, P.; Destribats, J. [CESTA - CEA Centre d' Etudes Scientifiques et Techniques d' Aquitaine, 33 - Le Barp (France); Legros, P. [Univ Bordeaux 2, Plate Forme Imagerie Cellulaire Inst Neurosci, Inst Francois Magendie, F-33076 Bordeaux (France); Ambard, C. [CEA Centre d' Etudes du Ripault, 37 - Tours (France)

2009-03-15

363

Imaging subsurface damage of grinded fused silica optics by confocal fluorescence microscopy  

International Nuclear Information System (INIS)

We report an experimental investigation of fluorescence confocal microscopy as a tool to measure subsurface damage on grinded fused silica optics. Confocal fluorescence microscopy was performed with an excitation at the wavelength of 405 nm on fixed abrasive diamond grinded fused silica samples. We detail the measured fluorescence spectrums and compare them to those of oil based coolants and grinding slurries. We evidence that oil based coolant used in diamond grinding induces a fluorescence that marks the subsurface damages and eases its observation. Such residual traces might also be involved in the laser damage process. (authors)

364

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

Directory of Open Access Journals (Sweden)

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.

Phan Bui Khoi

2015-03-01

365

Evaluation of minimum quantity lubrication grinding with nano-particles and recent related patents.  

Science.gov (United States)

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 supply system for the grinding fluid in nano-particle jet MQL, which produced MQL lubricant by adding solid nano-particles in degradable grinding fluid. The MQL supply device turns the lubricant to the pulse drops with fixed pressure, unchanged pulse frequency and the same drop diameter. The drops will be produced and injected in the grinding zone in the form of jet flow under high pressure gas and air seal. As people become increasingly demanding on our environment, minimum quantity lubrication has been widely used in the grinding and processing. Yet, it presents the defect of insufficient cooling performance, which confines its development. To improve the heat transfer efficiency of MQL, nano-particles of a certain mass fraction can be added in the minimum quantity of lubricant oil, which concomitantly will improve the lubrication effects in the processing. In this study, the grinding experiment corroborated the effect of nano-particles in surface grinding. In addition, compared with other forms of lubrication, the results presented that the grinding force, the friction coefficient and specific grinding energy of MQL grinding have been significantly weakened, while G ratio greatly rose. These are attributed to the friction oil-film with excellent anti-friction and anti-wear performance, which is generated nano-particles at the wheel/workpiece interface. In this research, the cooling performance of nano-particle jet MQL was analyzed. Based on tests and experiments, the surface temperature was assayed from different methods, including flood lubricating oil, dry grinding, MQL grinding and nano-particle jet MQL grinding. Because of the outstanding heat transfer performance of nano-particles, the ratio of heat delivered by grinding media was increased, leading to lower temperature in the grinding zone. Results demonstrate that nano-particle jet MQL has satisfactory cooling performance as well as a promising future of extensive application. PMID:23763268

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

2013-06-01

366

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)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

Walter Lindolfo, Weingaertner; Adriano, Boaron.

2012-03-01

367

Deformation behavior of a slab with width reduction in a hot mill  

Science.gov (United States)

The deformation of a slab with various width reductions has been investigated using a rigid-plastic finite-element analysis. A commercial finite-element code was used to analyze a dog-bone profile, mean thickness, length of slab, and longitudinal width profile after edging and horizontal rolling. The deformation behavior of a slab in a heavy edger mill was also compared with deformation in a sizing press. It was found that the sizing press followed by horizontal rolling is more efficient in width reduction than deformation by a heavy edger mill followed by horizontal rolling. The finite-element analysis results for the deformation of a slab also show reasonable agreement with measurements from an actual mill test, and from physical modeling experiments.

Chun, Myung-Sik; Ahn, Ick-Tae; Moon, Young-Hoon

2005-06-01

368

Analysis of roll gap heat transfers in hot steel strip rolling through roll temperature sensors and heat transfer models  

OpenAIRE

This paper presents an analysis of roll bite heat transfers during pilot hot steel strip rolling. Two types of temperature sensors (drilled and slot sensors) implemented near roll surface are used with heat transfer models to identify interfacial heat flux, roll surface temperature and Heat Transfer Coefficient HTCroll-bite in the roll bite. It is shown that: - the slot type sensor is more efficient than the drilled type sensor to capture correctly fast roll temperature changes and heat fluxe...

Weisz-patrault, Daniel; Ehrlacher, Alain; Legrand, Nicolas; Labbe, Nathalie; Horsky, Jaroslav; Luks, Tomas

2012-01-01

369

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

370

Experimental and numerical investigations of hydroerosive grinding for injection components  

Energy Technology Data Exchange (ETDEWEB)

Diesel injection injectors are very complicated hydraulic systems which contain among other things small throttles and small sized blow holes in order to inject the fuel precisely into the combustion chamber. Due to the extremely strong exhaust laws, the geometrical forms and tolerances of the hydraulic components have to be maintained. The hydroerosive grinding process (HE process) is used for manufacturing of small holes using in Diesel injection components. A mixture of oil and small sized particles are used to form the final geometrical shapes of the throttles and the blow holes. Simulation models help to understand the underlying physical process and to optimize the manufacturing parameters for an efficient production process. This paper presents an Euler-Euler approach for the numerical simulation of the HE process. It describes a two-phase slurry flow consisting of a liquid and a dispersed solid phase which causes wear at walls of devices. The continuous fluid phase is solved using a finite volume scheme in which the Large Eddy Simulation (LES) model is applied to resolve large-scale turbulent structures. The solid phase is disperse and treated as a second continuum in which drag and lift forces as well as added mass, pressure and history force are taken into account. Considering particle-particle interactions, the granular model from Gidaspow is used for particle volume concentrations over 1%. Investigations of erosion processes proofed that non-spherically shaped particles as well as harder particles increase the wear on devices significantly. Consequently, non-spherical particles are utilized for the hydroerosive grinding. Their steady drag, unsteady drag and lift coefficients, depending on the particle Reynolds number, are determined by a direct numerical simulation via an in-house LES Lattice-Boltzmann solver. This Lattice-Boltzmann method was presented for laminar flows by Hoelzer. In this work, interpolating functions of these coefficients are implemented in the Euler-Euler approach which enable the simulation of non-spherical particle transports. Hydroerosive grinding experiments in three-dimensional planar geometries with an optical access are carried out to determine an erosion model depending on particle impact velocity, particle size, particle concentration and wall hardness. The implementation of a mesh-morphing algorithm combined with the Euler-Euler scheme of the commercial solver ANSYS CFX11 enables an online simulation of the hydroerosive grinding process. Additionally, the online simulation is used to validate the applied numerical methods. Very good agreements are achieved and will be presented in this paper. (orig.)

Iben, Uwe; Weickert, Mathias [Robert Bosch GmbH, Stuttgart (Germany)

2011-07-01

371

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

372

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.

373

A Control Design for Grinding Systems with Feedforward Compensation  

OpenAIRE

The object of the present study is to design acontrol system for milling systems. An analyze of thedynamic behavior is described, aimed at designing acontrol system. The control system that is presenteduses PID control with feedforward compensation.

Costea, Claudiu Raul

2012-01-01

374

Application of electrolytic in-process dressing for high-efficiency grinding of ceramic parts. Research activities 1995--96  

Energy Technology Data Exchange (ETDEWEB)

The application of Electrolytic In-Process Dressing (ELID) for highly efficient and stable grinding of ceramic parts is discussed. This research was performed at the Institute of Physical and Chemical Research (RIKEN), Tokyo, Japan, June 1995 through August 1995. Experiments were conducted using a vertical machining center. The silicon nitride work material, of Japanese manufacture and supplied in the form of a rectangular block, was clamped to a vice which was firmly fixed on the base of a strain gage dynamometer. The dynamometer was clamped on the machining center table. Reciprocating grinding was performed with a flat-faced diamond grinding wheel. The output from the dynamometer was recorded with a data acquisition system and the normal component of the force was monitored. Experiments were carried out under various cutting conditions, different ELID conditions, and various grinding wheel bonds types. Rough grinding wheels of grit sizes {number_sign}170 and {number_sign}140 were used in the experiments. Compared to conventional grinding, there was a significant reduction in grinding force with ELID grinding. Therefore, ELID grinding can be recommended for high material removal rate grinding, low rigidity machines, and low rigidity workpieces. Compared to normal grinding, a reduction in grinding ratio was observed when ELID grinding was performed. A negative aspect of the process, this reduced G-ratio derives from bond erosion and can be improved somewhat by adjustments in the ELID current. The results of this investigation are discussed in detail in this report.

Bandyopadhyay, B.P. [Univ. of North Dakota, Grand Forks, ND (United States). Dept. of Mechanical Engineering

1997-02-01

375

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

376

Analysis on Large Deformation Compensation Method for Grinding Machine  

Directory of Open Access Journals (Sweden)

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.  

Wang Ya-jie

2013-08-01

377

Dry-grinded ultrafine cements hydration. physicochemical and microstructural characterization  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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).

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

2013-04-01

378

Effects of imbalance and geometric error on precision grinding machines  

Energy Technology Data Exchange (ETDEWEB)

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.

Bibler, J.E.

1997-06-01

379

Diamond blade grinding as a means for removing surface contamination from concrete  

International Nuclear Information System (INIS)

The use of a highway grinding unit for the decontamination of a 5,000 square foot surface is described. The type of equipment presently in use is described. Performance characteristics, waste collection and water usage are commented on. Variables in blade design are discussed. Feasibility of the grinding technique for water soluble contaminants and vertical surfaces is referred to

380

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

Scientific Electronic Library Online (English)

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.

Andreia Carolina, Rosa; Homero, Delboni Jr.

2014-06-01

381

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)

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)

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

382

Production of normalized steel plate through normalizing rolling; Producao de chapas grossas normalizadas diretamente do calor de laminacao  

Energy Technology Data Exchange (ETDEWEB)

Normalized plates can be got directly from the rolling heat through the use of a normalizing rolling process. In such way, an additional step of the conventional process of production of normalized plates - the normalizing heat treatment - can be suppressed, reducing the manufacturing cost of the product and shortening its production time. This relatively new production route is being used in several steelworks all over the world for many years. This work describes the implementation trials of normalizing rolling at COSIPA`s plate mill, using an alternative process of controlled rolling called recrystallization controlled rolling. The results got with new technique were successful, as it was able to produce plates with properties very similar to the conventionally normalized material, attending the requirements of the DIN 17100 RR 52-3N standard. This is one of many standards that permit the use of this new route of normalized steel plate production. (author) 14 refs., 8 figs., 2 tabs.

Gorni, Antonio Augusto; Cavalcanti, Celso Gomes; Reis, Jackson Soares de Souza; Silveira, Jose Herbert Dolabela da [Companhia Siderurgica Paulista (COSIPA), SP (Brazil)

1997-12-31

383

Improving the quality of rolled pipe steel products by minimizing the bending of the ends of plates  

Science.gov (United States)

The causes of the vertical bending of the front ends of plates during hot rolling are revealed. A finite-element mathematical model is developed to describe the state of stress of the metal in an asymmetric deformation zone with allowance for solving a temperature problem, and the model is adapted to the conditions of the 5000 rolling mill in OAO MMK. It is found that, in rolling with mismatched work roll speeds, the direction of bending of the front strip end is determined by the strip thickness and the deformation zone shape. The main cause of the bending of the front plate end at the stage of finishing stage of rolling is shown to be the difference between the roller bed level and the rolling line. New asymmetric deformation regimes are developed with allowance for the effect of the deformation zone shape on the direction of bending of the front strip end. The developed technological regimes of asymmetric rolling make it possible to decrease the mill downtime because of the bending of the breakdown bar ends and to reduce the metal volume rejected because of violated temperature regimes of the thermomechanical treatment of plates.

Salganik, V. M.; Chikishev, D. N.; Denisov, S. V.; Stekanov, P. A.; Shmakov, A. V.; Fomichev, A. V.

2013-11-01

384

Determination of the energy and power parameters during groove-rolling  

Directory of Open Access Journals (Sweden)

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.

S. Mróz

2007-06-01

385

Investigation of the Formation Process of Two Piracetam Cocrystals during Grinding  

Directory of Open Access Journals (Sweden)

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.

Keith Gordon

2011-10-01

386

Investigation of the formation process of two piracetam cocrystals during grinding  

DEFF Research Database (Denmark)

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.

Rehder, Sönke; Klukkert, Marten

2012-01-01

387

Real-Time Simulation of Robot Controlled Belt Grinding Processes of Sculptured Surfaces  

Directory of Open Access Journals (Sweden)

Full Text Available Industrial robots are introduced to belt grinding processes of free-formed surface with elastic wheel nowadays in order to obtain high quality product and high efficiency. However, it is a laborious task to plan grinding paths and write programs for the robot. To release people from it partially, it is necessary to simulate the belt grinding processes which are useful for path generating and dynamic robot control. In this paper, we present a framework of the robot controlled belt grinding simulation system and some key issues in it. We enhance the global removal model to local process model, which can simulate the grinding process more exactly. We also point out the bottleneck of the real-time simulation and put forward a neural network based regression method to meet this difficulty. At the end of the paper, some simple simulation examples are given.

Malik Cabaravdic

2008-11-01

388

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

389

Variation in crystallinity of hydroxyapatite and the related calcium phosphates by mechanical grinding and subsequent heat treatment  

Science.gov (United States)

The crystallinity of hydroxyapatite (HAp) and the related calcium phosphates for regenerating hard tissues was controlled by the mechanical grinding (MG) method and subsequent heat treatment. The HAp, carbonate-apatite (CO3Ap), fluorapatite (FAp), and ?- and ?-tricalcium phosphates ( ?-TCP and ?-TCP, respectively) and tetracalcium diphosphate monoxide (TTCP) were used as initial materials. Variations in crystallinity and crystal structure were examined by the X-ray diffraction (XRD) method during MG and the following heat treatment. The crystallinity, based on crystallite size and crystal elastic strain, decreased with grinding time, and the decreasing rate depended on the type of calcium phosphate; crystallographic diffraction peaks disappeared more rapidly in CO3Ap than in FAp. The change in the morphology of powder during MG was influenced by the primary particle size of the first-stage product; ?-TCP, ?-TCP, and TTCP powders composed of large particles were predominantly shattered into small pieces and then gathered during MG, while the crystal strain in the HAp, CO3Ap, and FAp powders was mainly accumulated without significant refinement of crystallite size. The thermal-recovery process of crystallinity and crystal structure in the milled powders was investigated. The crystallinity of HAp, CO3Ap, and FAp powders recovered depended on annealing temperature. The novel phase of ?’-TCP with higher ordering than ?-TCP appeared during heat treatment from the amorphous state of ?-TCP or ?-TCP obtained during MG. The MG and subsequent heat treatment were, finally, concluded to be an effective process for controlling the crystallinity and changing crystal structure in calcium phosphate powders.

Nakano, Takayoshi; Umakoshi, Yukichi; Tokumura, Atsuyuki

2002-03-01

390

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)

391

Nonlinear Observers for Parametric Roll  

OpenAIRE

Parametric roll resonance is a dangerous resonance phenomenon affecting several kinds of ships, such as cruise ships, fishing vessels and container ships. In a worst case scenario parametric roll resonance may lead to roll angles of up to 50 degrees, capsizing of the vessel, or damage of goods and ship for tens of millions of dollars, citep{Ginsberg1998}.Accurate equations in the model for the ship motion are important because they are directly related to the observer design. There has been d...

Olsen, Gunnhild Konstanse Hoff

2012-01-01

392

Kinematical characteristics of two-dimensional vertical ultrasonic vibration-assisted grinding technology  

Science.gov (United States)

The ultrasonic vibration-assisted machining (UVAM) technology is increasingly attractive for the ultraprecision machining of brittle materials. But the machining mechanism for UVAM is still unknown, especially for the grinding process. In this paper, the kinematical characteristics of two-dimensional vertical ultrasonic vibration-assisted grinding (UVAG) technology are investigated. A consistent physical modeling of the grinding process with ultrasonic vibration assistance is established firstly, which is based on the interaction of individual grinding grains with the workpiece. Then the kinematical equation is deduced, and so does the velocity and acceleration of a single abrasive grit relative to the workpiece in UVAG. The kinematics of a single abrasive grit during 2D UVAG is simulated for the perpendicular vibration mode. The results show that the relation motion of an abrasive grit is altered significantly with the assistance of ultrasonic vibration, and the grinding path is elongated, which will increase the material removal rate per abrasive grit. The most interesting result is that the relative velocity of an abrasive grit in UVAG is changed slightly when compared to that without ultrasonication. While the relative acceleration in UVAG is increasing tremendously, especially for high frequency ratio (a ratio between the vibration frequency to the rotation frequency) condition. This result means that the ultrasonic vibration assistance can introduce a huge acceleration impact on the material in the machining deformation zone by the grinding grit, and may change the material removal mechanism of grinding. Thus it can do a favor to the precision machining of brittle materials. The UVAG experiment of polysilicon shows that the surface roughness is improved and the normal and tangential grinding forces decrease with the increasing of applied voltage, while the axial grinding force increases. The results indicate that the assistance of ultrasonic vibration can result the change of the grinding mechanism of brittle material.

Peng, Y.; Wu, Y.; Liang, Z.; Guo, Y.

2010-10-01

393

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

1996-02-01

394

75 FR 16504 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia  

Science.gov (United States)

...Review)] Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil...on certain hot-rolled flat-rolled carbon-quality steel products (``hot-rolled...Supply conditions to consider include technology; production methods; development...

2010-04-01

395

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

Energy Technology Data Exchange (ETDEWEB)

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).

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

2014-04-23

396

Comparison of tungsten carbide and stainless steel ball bearings for grinding single maize kernels in a reciprocating grinder  

Science.gov (United States)

Reciprocating grinders can grind single maize kernels by shaking the kernel in a vial with a ball bearing. This process results in a grind quality that is not satisfactory for many experiments. Tungesten carbide ball bearings are nearly twice as dense as steel, so we compared their grinding performa...

397

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

398

Rolling Resistance Measurement and Model Development  

DEFF Research Database (Denmark)

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

Andersen, Lasse Grinderslev; Larsen, Jesper

2015-01-01

399

Direct measures of mechanical energy for knife mill size reduction  

Energy Technology Data Exchange (ETDEWEB)

Lengthy straw/stalk of biomass may not be directly fed into grinders such as hammer mills and disc refiners. Hence, biomass needs to be preprocessed using coarse grinders like a knife mill to allow for efficient feeding in refiner mills without bridging and choking. Size reduction mechanical energy was directly measured for switchgrass (Panicum virgatum L.), wheat straw (Triticum aestivum L.), and corn stover (Zea mays L.) in an instrumented knife mill. Direct power inputs were determined for different knife mill screen openings from 12.7 to 50.8 mm, rotor speeds between 250 and 500 rpm, and mass feed rates from 1 to 11 kg/min. Overall accuracy of power measurement was calculated to be 0.003 kW. Total specific energy (kWh/Mg) was defined as size reduction energy to operate mill with biomass. Effective specific energy was defined as the energy that can be assumed to reach the biomass. The difference is parasitic or no-load energy of mill. Total specific energy for switchgrass, wheat straw, and corn stover chopping increased with knife mill speed, whereas, effective specific energy decreased marginally for switchgrass and increased for wheat straw and corn stover. Total and effective specific energy decreased with an increase in screen size for all the crops studied. Total specific energy decreased with increase in mass feed rate, but effective specific energy increased for switchgrass and wheat straw, and decreased for corn stover at increased feed rate. For knife mill screen size of 25.4 mm and optimum speed of 250 rpm, optimum feed rates were 7.6, 5.8, and 4.5 kg/min for switchgrass, wheat straw, and corn stover, respectively, and the corresponding total specific energies were 7.57, 10.53, and 8.87 kWh/Mg and effective specific energies were 1.27, 1.50, and 0.24 kWh/Mg for switchgrass, wheat straw, and corn stover, respectively. Energy utilization ratios were calculated as 16.8%, 14.3%, and 2.8% for switchgrass, wheat straw, and corn stover, respectively. These data will be useful for preparing the feed material for subsequent fine grinding operations and designing new mills.

Bitra, V.S.P. [University of Tennessee; Womac, A.R. [University of Tennessee; Igathinathane, C. [Mississippi State University (MSU); Miu, P.I [University of Tennessee; Yang, Y.T. [University of Tennessee; Smith, D.R. [University of Tennessee; Chevanan, Nehru [University of Tennessee; Sokhansanj, Shahabaddine [ORNL

2009-08-01

400

FM Interviews: Stephanie Mills  

OpenAIRE

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 ...

Valauskas, Edward

2002-01-01

401

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

402

Roll Control in Fruit Flies  

OpenAIRE

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 ...

Beatus, Tsevi; Guckenheimer, John M.; Cohen, Itai

2014-01-01

403

Grease lubrication in rolling bearings  

CERN Document Server

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

Lugt, Piet M

2012-01-01

404

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

405

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

Science.gov (United States)

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.

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

2007-05-01

406

Numerical analysis of cross shear plate rolling  

DEFF Research Database (Denmark)

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.

Zhang, Wenqi; Bay, Niels

1997-01-01

407

Milling induces disorder in crystalline griseofulvin and order in its amorphous counterpart  

Energy Technology Data Exchange (ETDEWEB)

This study investigates two apparently similar thermal signatures, shaped as bimodal exotherms, observed when either the crystalline or the amorphous from of the drug are subjected to milling. Crystalline griseofulvin was cryomilled and the (quenched-melt) amorphous form was subjected to either cryomilling or grinding. The thermal and surface properties of the resulting samples were analyzed using differential scanning calorimetry (DSC) and surface energy analysis. After milling, both the crystalline and the amorphous material revealed visually similar bimodal exothermic events when the heating rate was 20 C min{sup -1}. Under different heating rates, the pair of DSC peaks for the bimodal exotherm of each material behaved entirely different from each other. The two peaks of the bimodal event, as well as the glass transition, can be kinetically resolved for the ground amorphous form using standard mode DSC. In contrast, similar analysis was unable to resolve the bimodal exotherm or a glass transition in the case of the cryomilled crystals. Furthermore, cryomilled crystals do not exhibit a glass transition even when analyzed using modulated DSC. Synchrotron sourced X-ray analysis revealed that grinding the amorphous material results in the nucleation and growth of the crystalline form. Milling thus induces disorder in the crystals of griseofulvin but induces order in the amorphous form of the drug. The surface of the two milled systems consistently exhibited different energetics under a wide range of relative humidity conditions. These findings suggest that cryomilling induces both bulk and surface disorder, specifically, a certain level of dislocations on the crystal. In contrast, grinding the amorphous material lowers the activation energy for crystal formation, inducing nuclei formation and growth throughout the amorphous matrix.

Otte, Andrew; Zhang, Yan; Carvajal, M. Teresa; Pinal, Rodolfo (Purdue)

2012-04-02

408

Effect of the Vibration Parameters on the Ultra-Fine Particles Preparation in a Dry Roller Vibration Mill  

Science.gov (United States)

The motion equations of the filling layers are established to study the motion traces of the filler in the chamber of vibration mill. The research results indicate that the filler does the rotary motion relative to the body center on the suitable vibration intensity, in the region of the center forms a steady circle motion, but in other regions forms a cascade motion, which makes up for the lack of the energy in the chamber's center and edge. Afterward, under a specific parameters combination, the single crystalline, transparent, uniform, randomly oriented, almost equiaxed Zn nanostructures are obtained in the roller vibration mill grinded 11 h, in order to test the simulation experiment.

Xu, Bo; Wang, Shulin; Li, Laiqiang

2013-07-01

409

Analysis of grinding of superalloys and ceramics for off-line process optimization  

Science.gov (United States)

The present study has compared the performances of resinoid, vitrified, and electroplated CBN wheels in creep feed grinding of M42 and D2 tool steels. Responses such as a specific energy, normal and tangential forces, and surface roughness were used as measures of performance. It was found that creep feed grinding with resinoid, vitrified, and electroplated CBN wheels has its own advantages, but no single wheel could provide good finish, lower specific energy, and high material removal rates simultaneously. To optimize the CBN grinding with different bonded wheels, a Multiple Criteria Decision Making (MCDM) methodology was used. Creep feed grinding of superalloys, Ti-6Al-4V and Inconel 718, has been modeled by utilizing neural networks to optimize the grinding process. A parallel effort was directed at creep feed grinding of alumina ceramics with diamond wheels to investigate the influence of process variables on responses based on experimental results and statistical analysis. The conflicting influence of variables was observed. This led to the formulation of ceramic grinding process as a multi-objective nonlinear mixed integer problem.

Sathyanarayanan, G.

410

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

Science.gov (United States)

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

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

2014-01-01

411

Electrolytic in process dressing (ELID) applied to double side grinding of ceramic materials  

Science.gov (United States)

The objective of the present work is to design, optimize, and validate an electrolytic in-process dressing (ELID)-assisted double side grinding process for finishing advanced ceramic components. To attain this objective, an original ELID double side grinding system was designed, fabricated, and operated at Precision Micro-Machining Center at The University of Toledo, Ohio. The ELID technique was selected from among other options to assure the in-situ dressing of the metal-bonded superabrasive grinding wheel and to maintain its cutting ability throughout the operation, which is, otherwise, a challenging enterprise. Optimizing the ELID double side grinding process parameters is an important goal of the present study. To achieve this goal, a complex integrated model was developed and validated through extensive experimental testing. Four analytical computerized models were developed and integrated: (1) an improved kinematic model of double side grinding accounting for workpiece rotation, which is used to simulate the grinding trajectories; (2) a microscopic model of the interaction between a single diamond grit and the work surface, which is used to predict the volume of material removed; (3) a stochastic model for the topographical characterization of the superabrasive wheel, which leads to a new prediction method of depth of indentation; and (4) an electrolytic oxidation model, which explains the dynamics of the oxide layer. In order to validate the models and to confirm the optimized process, experimental tests were conducted under different conditions: with vitrified and metallic bond grinding wheels, with various average grain sizes of diamond grits, with different superabrasive concentrations, with different grinding fluids, with and without ELID assistance. Our findings show that an optimized ceramic double side grinding process using fine diamond grit is more efficient than lapping in producing very fine surfaces. The experiments confirmed the superiority of ELID-assisted DSG over the conventional operation in terms of productivity, surface finish and geometrical precision of the ground surfaces, ease of wheel maintenance, and prevalence of ductile material removal mode.

Spanu, Cristian E.

412

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)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish 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.

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

413

The disposal of solid wastes and liquid effluents from the milling of uranium ores  

International Nuclear Information System (INIS)

Current Canadian practice in the milling of uranium-bearing ores commonly involves fine grinding followed by acid leach/ion exchange. The acid leach may be followed instead by solvent extraction. Alkaline leaching has been done, and in situ bacteriological leaching is of interest. Tailings disposal operations are necessary and create environmental problems. Uranium-mill wastes are unique because of their radioactivity. Some of the radioisotopes present may require an individual control procedure. Radium-226 is particularly important because it is the most hazardous of all isotopes found in the tailings. Acid and heavy-metal removal is conventionally done by the addition of lime, but other means are available, such as with limestone, sodium hydroxide, ammonia, silicon alloys or by sulphide precipitation. Modifications to unit operations in the mill process may be required to produce more acceptable effluents. Increased water recycling may be necessary to meet regulatory standards. (author)

414

Development of roll-to-roll hot embossing system with induction heater for micro fabrication  

Science.gov (United States)

In this paper, a hot embossing heating roll with induction heater inside the roll is proposed. The induction heating coil is installed inside a roll that is used as a heating roll of a roll-to-roll (R2R) hot embossing apparatus. Using an inside installed heating coil gives the roll-to-roll hot embossing system a more even temperature distribution on the surface of the heating roll compared to that of previous systems, which used an electric wire for heating. This internal induction heating roll can keep the working environment much cleaner because there is no oil leakage compared to the oiled heating roll. This paper describes the principles and provides an analysis of this proposed system; some evaluation has also been performed for the system. A real R2R hot embossing heating roll system was fabricated and some experiments on micro-pattering have been performed. After that, evaluation has been performed on the results.

Yun, Dongwon; Son, Youngsu; Kyung, Jinho; Park, Heechang; Park, Chanhun; Lee, Sunghee; Kim, Byungin

2012-01-01

415

Effect of Superfine Grinding on Antidiabetic Activity of Bitter Melon Powder  

OpenAIRE

The antidiabetic activities of bitter melon powders produced with lyophilization/superfine grinding and hot air drying/normal grinding were investigated in vivo for selecting a suitable bitter melon processing procedure. After a five-week treatment, bitter melon lyophilized superfine grinding powder (BLSP) had a higher antidiabetic activity with reducing fasting blood glucose levels from 21.40 to 12.54 mmol/L, the serum insulin levels from 40.93 to 30.74 mIU/L, and restoring activities of SOD...

Zhiyu Xiong; Yi Zhang; De Yun Wang; Xinghua Zhou; Qin Guo; Xiwen Qian; Fengjie Cui; Ying Dong; Ying Zhu

2012-01-01

416

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

OpenAIRE

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...

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

1999-01-01

417

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 specific surface was highly correlated with the gluten content (r=0.90.

Devaux M.F.

1999-09-01

418

Effect of Grinding Induced Damage on Bending Strength of RBSiC  

Directory of Open Access Journals (Sweden)

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.

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

2009-03-01

419

Simulation and analysis of grinding wheel based on Gaussian mixture model  

Science.gov (United States)

This article presents an application of numerical simulation technique for the generation and analysis of the grinding wheel surface topographies. The ZETA 20 imaging and metrology microscope is employed to measure the surface topographies. The Gaussian mixture model (GMM) is used to transform the measured non-Gaussian field to Gaussian fields, and the simulated topographies are generated. Some numerical examples are used to illustrate the viability of the method. It shows that the simulated grinding wheel topographies are similar with the measured and can be effective used to study the abrasive grains and grinding mechanism.

Chi, Yulun; Li, Haolin

2012-12-01

420

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.

421

Corn Wet Milling Lab  

Science.gov (United States)

Description: Wet Corn Milling is an industrial process that that converts corn to a wide variety of by-products. The wet milling industry is the largest non-feed user of corn, using approximately 1 billion bushels annually. This lab looks at the separation steps in the industrial processing of corn.

Olson, Eric

422

Development of CRE (Cross Roll Edge-bend) method for ERW pipe forming; Denho kokan seikei ni okeru CRE (Cross Roll Edge-bend) ho no kaihatsu (koseido, kohinshitsu edge bend gijutsu no kaihatsu)  

Energy Technology Data Exchange (ETDEWEB)

The new CRE (Cross Roll Edge-bend) method was developed for ERW piping mills forming various thin and thick ERW pipes which is featured by high roll compatibility and edge formability possible to cope with change in outside diameter and wall thickness, and keep a stable product quality. The CRE method adjusts the gap profile composed by crossing upper and lower rolls so as to meet the proper bending curvature and wall thickness. The forming test result on a prototype testing stand and numerical analysis result clarified the following effects. The compatibility of rolls by swing of rolls was proved in a bending curvature range within 1.5 times. By crossing upper and lower rolls in a direction that the surface track of an upper roll shifts from the edge portion to center portion of formed materials, bending moment effectively served to improve the edge formability. By giving the suitable swing angle of an upper roll according to the wall thickness of pipes, the high-precision edge formability with less impression defects was achieved. 2 refs., 15 figs., 3 tabs.

Hada, K.; Osawa, T.;