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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

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 o...

Ajaka E. O.; Akinbinu V. A.

2011-01-01

3

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

4

Rheology of coal-water slurries prepared by the HP roll mill grinding of coal. Quarterly technical progress report No. 6, December 1, 1993--February 28, 1994  

Energy Technology Data Exchange (ETDEWEB)

The effect of the addition of nonionic surfactants on the aggregative stability of coal-water slurries was investigated through determination of sedimentation volumes and floc size distributions. Sedimentation volume measurements for nonionic surfactants show that for Triton X-165, Triton X-305 and Triton X-405, the sedimentation volume decreases slightly with added reagent up to 0.5 wt % addition, decreasing sharply for reagent additions between 0.5 to 0.75 wt %. However, at higher additions, the sedimentation volume levels off for Triton X-165, but increases for both Triton X-305 and Triton X-405. These results are in agreement with the viscosity measurements. Because of its plastic nature, bituminous coal is readily briquetted or agglomerated by the intense localized stresses encountered during comminution in the high-pressure roll mill. The degree of briquetting depends on the nature of the coal and the compressive stresses. We have found that the briquettes can readily be deagglomerated by stirring the comminuted products in a in methanol suspension. Our results show that the amount of minus 200-mesh coal produced depends mainly on the energy invested in the high-pressure roll grinding. The percentage of fines generated increases more or less linearly with the specific grinding energy consumed in the initial stages and tends to level off at the high energy inputs higher than 3 kwh/t. Even at 3.74 kWh/t of energy input, the ground product contained only 30 percent of minus 200-mesh particles, which is much lower than 80 percent of minus 200-mesh particles required in the coalwater slurries for direct combustion in power plants. Therefore, future work will encompass grinding of the high-pressure roll milled product in ball mill or rod mill, using hygrid HP roll mill/ball mill circuit for feed preparation.

Fuerstenau, D.W.

1994-03-01

5

Influence parameters of impact grinding mills  

Science.gov (United States)

Significant parameters for impact grinding mills were investigated. Final particle size was used to evaluate grinding results. Adjustment of the parameters toward increased charge load results in improved efficiency; however, it was not possible to define a single, unified set to optimum grinding conditions.

Hoeffl, K.; Husemann, K.; Goldacker, H.

1984-01-01

6

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)

7

Grinding arrangement for ball nose milling cutters  

Science.gov (United States)

A grinding arrangement for spiral fluted ball nose end mills and like tools includes a tool holder for positioning the tool relative to a grinding wheel. The tool is mounted in a spindle within the tool holder for rotation about its centerline and the tool holder is pivotably mounted for angular movement about an axis which intersects that centerline. A follower arm of a cam follower secured to the spindle cooperates with a specially shaped cam to provide rotation of the tool during the angular movement of the tool holder during the grinding cycle, by an amount determined by the cam profile. In this way the surface of the cutting edge in contact with the grinding wheel is maintained at the same height on the grinding wheel throughout the angular movement of the tool holder during the grinding cycle.

Burch, C. F. (inventor)

1974-01-01

8

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.)

9

Specific features related to pulverizing wet coals in a roll mill  

Science.gov (United States)

Results from a calculation and experimental study of pulverizing wet brown coal in a roll mill are presented. The influence of moisture content in coal, types of grinding rollers, and effectiveness of separating the pulverization products in the separator on the mill output is estimated.

Shuvalov, S. I.; Mikheev, G. G.

2010-08-01

10

The Influence of Hammer Type Used in Grinding Mills on Grist Fineness  

Directory of Open Access Journals (Sweden)

Full Text Available Hammer mills are machines used in agriculture graded to obtain concentrated fodder mix and food industry for grinding vegetable raw materials necessary for obtaining various types of flours. The hammer mills grinding materials is produced upon impact of the hammer material and crushing plate located inside the grinding chamber. Depending on the hammers rotor assembly mode, the following types of mills can be used: - Hammer mills articulated; - Fixed Hammer mills. The objective of this paper is to study the influence of moisture during the operation of grinding wheat on hammer mills using the same sieve.

Mircea Valentin Muntean

2013-11-01

11

Fine grinding of brittle minerals and materials by jet mill  

Directory of Open Access Journals (Sweden)

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

Lek Sikong

2008-05-01

12

The specific selection function effect on clinker grinding efficiency in a dry batch ball mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dry grinding experiments on cement clinker were carried out using a laboratory batch ball mill equipped with a torque measurement. The influence of the ball size distribution on the specific selection function can be approached by laboratory runs using mono-size balls. The breakage is more efficient with maximal specific selection functions at the initial size reduction stage. But, in terms of cement finish grinding all stages of grinding are determinant for the production of a required Bl...

Touil, Djamel; Belaadi, Salah; Frances, Christine

2008-01-01

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Radiotracer Investigation of Clinker Grinding Mills for Cement Production at Ghacem  

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Full Text Available Radiotracer Residence Time Distribution (RTD method was used to investigate the process of clinker grinding in Ghana Cement Plant (GHACEM at Tema with the objective of determining hold-up and grinding efficiencies of two ball mills operating in close circuit regime. The experiment was conducted using 40Ci Au-198 radiotracer in liquid state and highly sensitive NaI detectors for radiation measurement. The experimental RTD data revealed that the Mean Residence Times (MRT of the material in the milling and separator sections of both mills were the same. It was also observed from the estimated mill efficiencies that mill 4 operated with optimal performance while the efficiency of mill 3 was far below the expected value.

Ishmael Iddisah Mumuni

2011-01-01

14

Radiotracer Investigation of Clinker Grinding Mills for Cement Production at Ghacem  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Radiotracer Residence Time Distribution (RTD ) method was used to investigate the process of clinker grinding in Ghana Cement Plant (GHACEM) at Tema with the objective of determining hold-up and grinding efficiencies of two ball mills operating in close circuit regime. The experiment was conducted using 40Ci Au-198 radiotracer in liquid state and highly sensitive NaI detectors for radiation measurement. The experimental RTD data revealed that the Mean Residence Times (MRT) of the material in ...

Ishmael Iddisah Mumuni; C P K Dagadu, K. A. Danso

2011-01-01

15

Production of a diluted solid tracer by dry co-grinding in a tumbling ball mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a study on the production by co-grinding of a diluted solid tracer, sized less than 10 mm and containing less than 2 wt. % of active product, used in the field of grounds contamination and decontamination. Co-grinding was performed in a tumbling ball mill and permits to produce easily a diluted tracer without implementing several apparatus. The two products were ground separately first and then together. The follow-up of the particles size and morphology, as...

Le Bolay, Nadine; Zapata-massot, Ce?line; Barthe, Laurie; Ahmed, Zakarya

2008-01-01

16

Classifiers for roller grinding mills - review and current state of development. Waelzmuehlensichter - Rueckblick und gegenwaertiger Entwicklungsstand  

Energy Technology Data Exchange (ETDEWEB)

A description is given of the current state of development of classifiers for roller grinding mills, starting with a historical review; the theoretical potential for changing a characteristic curve by using a classifier is discussed. More specifically, descriptions are given of the structure and function of the standard model of the static centrifugal classifier, the optimized form of the static centrifugal classifier, the dynamic screen basket classifier, the dynamic rotor classifier (bladed-rotor classifier), the high-efficiency guide-vane bladed-rotor classifier, and the high-efficiency louvre rotor classifier. The functional interaction between the roller grinding mill and the top-mounted classifier is explained. Characteristic particle size curves are then used to compare the action of a dynamic bladed rotor with that of a high-efficiency louvre rotor classifier when grinding and classifying different materials. Finally, there is a discussion of the effects on the required mill throughput. (orig.)

Brundiek, H.

1993-08-01

17

Optimum condition determination of Rirang uranium ores grinding using ball mill  

International Nuclear Information System (INIS)

The grinding experiment on Rirang Uranium ore has been carried out with the aim is to find out the optimum condition of wet grinding using ball mill to produce particle size -325, -200 and -100 mesh. This will be used for decomposition feed the test was done by examine the parameters comparison of ore's weight against ball's weight and time of grinding. The test shown that the product of particle size -325 meshes was achieved optimum condition at the comparison ore's weight: ball = 1:3, grinding time 150 minutes, % solid 60, speed rotation of ball mill 60 rpm and recovery of grinding was 93.51 % of -325 mesh. The product of particle size -200 mesh was achieved optimum condition at comparison ore's weight: ball = 1:2, time of grinding 60 minutes, the fraction of + 200 mesh was regrind, the recovery of grinding 6.82% at particle size of (-200 + 250) mesh, 5.75 % at (-250 + 325)m mesh and, 47.93 % -325 mesh. The product of particle size -100 mesh was achieved the optimum condition at comparison ore's weight: ball = 1:2, time of grinding at 30 minutes particle size +100 mesh regrinding using mortar grinder, recovery of grinding 30.10% at particle size (-100 + 150) m, 12.28 % at (-150 + 200) mesh, 15.92 % at (-200 + 250) mesh, 12.44 % at (-250 + 325) mesh and 29.26 % -325 mesh. The determination of specific gravity of Rirang uranium ore was between 4.15 - 4.55 g/cm3

18

Structural causes of defects in a cast iron mill roll  

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Full Text Available 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 carefully the propagation of the fracture. There was found a strict correlation between the microstructure of the roll and the progress occurring in the crack. It was ascertained that the basic reason for the damage to the roll was banded precipitations of ledeburitic cementite. In addition, cementite formed a continuous network. Another microstructure defects of that roll are also precipitations of secondary carbides on the boundaries of former grain of austenite as well as the occurrence of upper bainite in its matrix. The results obtained hereunder allow broadening the data base relative to the genesis of damages to mill rolls, which in future will permit one to design a proper microstructure of cast iron mill rolls. Proper microstructure of cast iron mill roll should be shaped at the stage of designing the chemical composition, conditions of crystallization or heat treatment if any.

J. Krawczyk

2008-07-01

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Wear of hot rolling mill rolls: An overview  

Science.gov (United States)

Rolling is today one of the most important industrial processes because a greater volume of material is worked by rolling than by any other technique. Roll wear is a multiplex process where mechanical and thermal fatigue combines with impact, abrasion, adhesion and corrosion, which all depend on system interactions rather than material characteristics only. The situation is more complicated in section rolling because of the intricacy of roll geometry. Wear variables and modes are reviewed along with published methods and models used in the study and testing of roll wear. This paper reviews key aspects of roll wear control - roll material properties, roll pass design, and system factors such as temperature, loads and sliding velocity. An overview of roll materials is given including adamites, high Cr materials, high speed tool steels and compound rolls. Non-uniform wear, recognized as the most detrimental phenomenon in section rolling, can be controlled by roll pass design. This can be achieved by computer-aided graphical and statistical analyses of various pass series. Preliminary results obtained from pilot tests conducted using a two-disc hot wear rig and a scratch tester are discussed.

Spuzic, S.; Strafford, K. N.; Subramanian, C.; Savage, G.

1994-08-01

20

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

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

Farzaneh Ahmadzadeh

2013-06-01

 
 
 
 
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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

Energy efficiency of cement finish grinding in a dry batch ball mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dry grinding experiments on cement clinker were carried out using a laboratory batch ball mill equipped with torque measurement. The specific energy was found to be dependent on operating parameters and clinker environment. Additional compounds such as gypsum and pozzolanic tuff improve energy efficiency. The optimal parameters allowing maximising the energy efficiency factor were determined. Energy efficiency factors were obtained both on the crude material (size minus 2.8 mm) and on a sieve...

Touil, Djamel; Belaadi, Salah; Frances, Christine

2006-01-01

23

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

24

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

25

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

Scientific Electronic Library Online (English)

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

26

Digital technology for radiometric thickness gages in rolling mills  

International Nuclear Information System (INIS)

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

27

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-03-15

28

Dimensional ranges and rolling efficiency in a tandem cold rolling mill  

Energy Technology Data Exchange (ETDEWEB)

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

Larkiola, J.

1997-12-31

29

On mill flow rate and fineness control in cement grinding circuits: instability and delayed measurements  

International Nuclear Information System (INIS)

A control structure for the mill flow rate and the product fineness is designed, with the feed flow rate and the classifier characteristic as the manipulated variables. Experimental results from a plant highlight the instability of the grinding circuit. A model previously developed by the authors stresses the major influence of the classifier nonlinearities onto this instability. A cascade control structure has been designed and implemented on site. The measurements of the product fineness, sensitive to material grindability fluctuations, are randomly time-delayed. The control structure uses a fineness estimator based on an adaptive scheme and a time delay compensator. (author)

30

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

31

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-07-01

32

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-09-20

33

Development of rolling mill for rectangular orthodontic wires production  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

34

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

35

Optimize cold sector material flow of a steel rolling mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Baudet, Alvaro

2010-01-01

36

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

37

REDESIGN OF THE LUBRICATION AND SEALING SYSTEM AT THE ROLLING MILL STAND BEARING  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thesis presents a reconstruction of the sealing and lubrication device support cylinders rolling mill aluminium foil in the company Impol d.d. The objective function is the passage of lubricating oil present in the mill and back, and only this is also eliminated. In the introduction to the description of the company Impol and the process of rolling aluminium foil. Proceed with presentation of various techniques of sealing and lubrication used on the machines, with an emphasis on rolling. ...

S?turm, Sebastijan

2012-01-01

38

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

39

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

International Nuclear Information System (INIS)

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

40

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.

 
 
 
 
41

Strip/Foil Rolling Mill Stochastic Excitation Model and Its Stability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Based on the stochastic rolling force data from aluminum hot strip tandem mill, the ARMA time series model and the stochastic excitation power spectral density (PSD) model are established, and the stochastic rolling forces excitation model is established by utilizing Levenberg-Marquardt combined with generalized global planning algorithm. A two dimensional stochastic nonlinear dynamical model of rolls is presented considering the stochastic factor of the rolling force. The Hamilton function i...

Baoyu Xu; Xudong Wang; Yilun Liu; Haichao Feng

2012-01-01

42

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

43

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

44

The new PFEIFFER roller mill MVR. Reliable grinding technology for high throughput rates; Die neue PFEIFFER-MVR-Walzenschuesselmuehle. Sichere Mahltechnik fuer grosse Durchsaetze  

Energy Technology Data Exchange (ETDEWEB)

In the cement industry, the trend is towards ever increasing grinding capacities of individual grinding plants. As a result, plant availability and optimized maintenance concepts are becoming more and more important. The newly developed MVR roller mill from Gebr. Pfeiffer AG for grinding cement raw material, cement clinker, and additives with an installed power of up to 12 000 kW does in fact fulfill these customer requirements perfectly. The modular design of the MVR mill comprising 4 to 6 grinding rollers allows the continuation of mill operation even if one roller module is not available. The same applies to the new MultiDrive {sup registered} design of the mill drive consisting of up to 6 identical drive units in the range of 2000 kW each. So mill operation may continue while maintenance work is being performed on a drive unit. Hence any unplanned downtimes are considerably reduced even in the case of an outage of the main components. (orig.)

Reichardt, York [Gebr. Pfeiffer AG, Kaiserslautern (Germany). Process Engineering Dept.

2010-07-01

45

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)

46

Rolling process simulation of a pair-crossed hot strip mill  

Energy Technology Data Exchange (ETDEWEB)

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)

Chen Shaojie; Xu Jianzhong; Liu Xianghua; Wang Guodong [Northeastern Univ., State Key Lab of Rolling and Automation, Shenyang City (China)

2000-07-01

47

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

Science.gov (United States)

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

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

2012-02-01

48

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

49

Force prediction in cold rolling mills by polynomial methods  

Directory of Open Access Journals (Sweden)

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

Nicu ROMAN

2007-12-01

50

Fine grinding of hematite for making pigment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The study of hematite dry and wet grinding by means of two different kinds of mill, i.e. Hardgrove mill and jar mill in the presence and absence of grinding additives, is presented in this paper. It was apparent that dry grinding with calcium stearate as grinding aid could improve the efficiency due to its Inbricating effect and deagglomeration of fines, while in wet process dispersant such as sodium hexametaphosphate was required to increase the grinding rate and prevent the agglomeration of...

Lek. Sikong; Thitipun Pongramun; Natsima Phunmuang

2001-01-01

51

Regulation of the Heating Furnace in Tube Rolling Mill  

Directory of Open Access Journals (Sweden)

Full Text Available The rolling of tube requires homogeneous heating along the tube. In steel work the difference along tube was sometimes 80 °C. The reasons for bad homogeneousness of heating were analyzed by a simulation model of heating furnace. Then the proposal was made for a new control system and also the proposal for reconstruction of furnace. In this contribution also a description of some ways for improvement of heating was made. The main contribution is the proposal of an adaptive system

Kostúr, K.

2006-01-01

52

Regulation of the Heating Furnace in Tube Rolling Mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rolling of tube requires homogeneous heating along the tube. In steel work the difference along tube was sometimes 80 °C. The reasons for bad homogeneousness of heating were analyzed by a simulation model of heating furnace. Then the proposal was made for a new control system and also the proposal for reconstruction of furnace. In this contribution also a description of some ways for improvement of heating was made. The main contribution is the proposal of an adaptive system

Kostu?r, K.

2006-01-01

53

Research on Single-Side Long Edge of Hot Rolled Strip Caused by Asymmetrical Stiffness of Mill Stand  

Directory of Open Access Journals (Sweden)

Full Text Available To analyze and solve the problem of single-side long edge of hot rolled strip in certain domestic factory, the asymmetrical deformation of rolls and strip in asymmetrical stiffness mill stand based on slit beam model, the strip profile and rolling force distribution at the exit of asymmetric stiffness stand mill were calculated using influence function method. Considering the character of in-site equipment and technology, a scheme of adjusting load distribution in finishing mill was made and the experiment was applied. Comparison of strip profile between new load distribution and the old one shows that the method can solve single-side long edge problem well.

Dian-Yao Gong

2011-09-01

54

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

Scientific Electronic Library Online (English)

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

Design of Rolling State Observers for Application to Control of Thickness and Tension in Rolling Mills  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study focuses on the necessity of designing state observers to be used in controller synthesis for rolling processes. This is motivated by the fact that using several kinds of sensors for measuring all of process variables is technically and economically avoided. On the other hand, using exact measurement in feedback control systems could considerably improve the quality of products. In other word, there is a trade-off between high quality and the implementation limitations, managed here...

Koofigar, Hamid R.; Shahab Amelian

2011-01-01

56

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

57

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

58

Mechanism of Oxidation of Austenitic Stainless Steels under Conditions of Hot Rolling in Steckel Mills  

Science.gov (United States)

The development of oxide scales on hot-rolled austenitic stainless steels under conditions imposed by the industrial Steckel Mill operation introduces particular characteristics that impact downstream on the surface quality of the hot-rolled strip product. In this research, the development of these particular surface structures were studied on 302 austenitic stainless steel by means of laboratory process simulation involving mechanical deformation in a multipass hot rolling schedule and long interpass time inside equalizing furnaces. Surface analysis using a set of complementary techniques that included field emission gun scanning electron microscopy (FEG-SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and glow discharge optical spectroscopy (GDOS) provided a full characterization of the resulting surface structures. These structures consisted in multiple oxide scale and metal layers that were developed after each rolling pass and heavily modified by the following rolling operation establishing a single repetitive mechanism of surface development. The mechanism of formation of these complex multilayer surface structures has been fully determined as being associated with a cyclic oxidation pattern involving successive stages of protective oxidation, chemical breakaway, and the progress of duplex oxidation.

Cobo, S. J.; Palmiere, E. J.; Rainforth, W. M.

2008-10-01

59

Bearing restoration by grinding  

Science.gov (United States)

A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

1976-01-01

60

Choice of technology for speed measurement in a cold rolling mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An often encountered problem when implementing a mass flow regulator in a rolling mill is the one with measurement of speed. The most widely used solution is to fit a pulse counter to a wheel that is in contact with the strip. Common problems with this design are for instance scratch marks on the strip and problems with the flatness measuring system.  One way of circumventing the aforementioned problems would be a non-contact measuring system. The market of today only offers systems based on...

O?ling, Martin

2013-01-01

 
 
 
 
61

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

62

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

63

Physical modelling of plastic deformation conditions for the rolling proces of AZ31 bars in a three high skew rolling mill  

Directory of Open Access Journals (Sweden)

Full Text Available The article presents results of the research concerning the physical modeling of plastic working of AZ31 magnesium alloy using two research methods. These studies were conducted using a metallurgical process simulator and torsional plastometer. The research was done for temperature range 200 ÷ 400 °C and strain rate from 0,1 to 20,0 s-1, depending on the testing method. The results allow to determine the coefficients in yield equation needed for the numerical research. Moreover the most advantageous temperature - velocity conditions to realize the process of bars rolling in three high skew rolling mill can be determined.

A. Gryc

2014-10-01

64

Validation of a 3-D, Thermo-Mechanically Coupled Model for Multi-Pass Rolling in a Reversing Mill  

Energy Technology Data Exchange (ETDEWEB)

A three dimensional numerical model simulating multi-pass, hot rolling on a reversing mill has been developed to analyze deformation patterns and shape changes of a rolled ingot. Validation simulations through 15 passes with an 86% reduction have been performed using the thermo-mechanically coupled model to track the evolution of the deformed ingot geometry. The heat transfer coefficient for thermal conduction between the rolls and slab has been estimated in accordance with experimental data, and heat transfer to the air and coolant outside of the roll bite is included. A hyperbolic sine model using the Zener-Hollomon parameter is used to capture the temperature and strain rate dependence of the aluminum alloy. A Coulomb friction model with a flow strength dependent maximum limit on the interfacial shear stress was employed between the rolls and ingot. Results of validation simulations and comparisons with experiments focusing on the ingot shape evolution are discussed.

Rhee, M; Wang, P; Li, M; Becker, R

2004-01-30

65

Finite elements method (FEM simulation based prediction of deformation and temperature at rolling of tubes on a pilgrim mill  

Directory of Open Access Journals (Sweden)

Full Text Available 3D - FEM simulation was used as an efficient tool for description of stress-deformation thermal field at rolling of tubes on a pilgrim mill. The monitored objectives comprised also behaviour of working tools at this rolling. This paper assumes rolling of already pierced thick-walled blank, which passes through the pilgrim stand at simultaneous reduction of thickness of inside and outside diameters at the expense of elongation of initial length. Main attention is focused on the mentioned parameters with respect to various conditions of rolling, such as different heat transfer, different friction or different distance of insertion of the rolled product into the gauge. The input data used at simulation were derived from real conditions of tubemaking.

R. Kocich

2009-10-01

66

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

Scientific Electronic Library Online (English)

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

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

2011-07-01

67

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

68

Set of automatic nondestructive testing means for the quality control of pipes in production line of '140' rolling mill  

International Nuclear Information System (INIS)

Devices and installations are described forming a system of subsidiary mechanical equipment and means of automatization for testing hot-rolled ferromagnetic steel pipes in the finishing line of ''140'' pipe-rolling mill. The main features of the system are as follows: it is equipped with automatic control devices which supply objective information on the quality of the pipes; the non-destructive test equipment is automatic, thus rapid and reliable; auxiliary joints and devices are unificated, so that the separate stages of control can be quickly re-organized. A computer collects and stores information on tested pipes of the rolled lot and can supply it type-written. Computer-treated results of tests during a certain period, if analysed with regard for smelting and rolling technology, may be used as technological advice on improvement of production and may probably provide for savings on steel deformation processes

69

Study on Online Analysis of Transfer Function of Variable-Speed Rolling Mill Motor with Shaft Torsional Vibration Systems  

Science.gov (United States)

The torsional vibration between metal rolling rolls and a rolling mill motor, may occur in recent days, as a result of higher speed response adjustment for variable speed rolling mill motor drive system. Issues in this paper are focused on excess acceleration value, in tangential direction of the mill motor rotor, which is caused by the motor shaft torsional resonance at the white noise signal superposition to the speed reference signal of the motor drive system for the online transfer function analysis. As a result of the acceleration analysis, the acceleration values in “G” (Relative acceleration value on the basis of Gravity) can be plotted on “Bode-Diagram”, which is namely frequency response for the speed signal amplitude transmission ratio. In addition, relation between the white noise amplitude reduction and the transfer function analysis accuracy deterioration is also examined, in this paper. As the amplitude of the white noise decreases, the analysis error increases because of the reduction in the resolution when the amplitude of the white noise signal is small.

Tamaoki, Toshifumi; Takanezawa, Makoto; Kimoto, Masanori; Morita, Noboru; Hoshino, Takeo; Hashizume, Kenji

70

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Vukmirovi? ?uro M.; Fišteš Aleksandar Z.

2009-01-01

71

STUDIES ON CONTINUOUS GRINDING PROCESS FOR DRIED WATER CHESTNUT KERNEL  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 cons...

Garg, S. K.; Lohani, U. C.; Pandey, J. P.

2010-01-01

72

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

73

Controller-optimizer of ball mill performance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work is dedicated to regulator-optimizer ball drum mills to increase energy and economic efficiency of grinding material (coal, clinker, etc.). Developed regulatory optimizer provides continuous monitoring of key parameters of milling process (ventilation, drainage and grinding performance, load, mill, etc.), and optimization of mill grinding for maximum performance.

Pistun, Ye; Zahray, V.; Fedoryshyn, R.

2011-01-01

74

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 def...

Laber, K.; Dyja, H.; Ka?amorz, M.

2015-01-01

75

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

76

Effect of rolling parameters on the properties of Al-Fe-V sheet rolled on an experimental mill  

International Nuclear Information System (INIS)

In recent years, interest in high temperature aluminum alloys has increased. However, nearly all the data available is for simple extrusions. This paper looks at the properties of sheet made from a rapidly solidified Al-10Fe-2.5V-2Si alloy. The sheet is made by direct forging followed by hot rolling, this is readily scalable, so allowing the production of large sheet. The room temperature strength and fracture toughness of the sheet are comparable to those of 2014-T6. The high temperature strength, specific stiffness and corrosion resistance are excellent. Recently, improved thermomechanical processing and new alloys have allowed higher strengths and fracture toughness values to be obtained

77

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

78

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

79

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

Scientific Electronic Library Online (English)

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

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

2013-03-01

80

Messy Grind  

Science.gov (United States)

This image shows the results of the Mars Exploration Rover Opportunity's grinding of its first target with the rock abrasion tool, located on its instrument deployment device, or 'arm.' The target, called 'McKittrick,' is located on the 'El Capitan' region of the rock outcrop at Meridiani Planum, Mars. The grinding process at 'McKittrick' has generated a significant amount of fine-grained, reddish dust. Color and spectral properties of the dust show that it may contain some fine-grained crystalline red hematite. This image is an enhanced color composite generated from three different panoramic camera filters.

2004-01-01

 
 
 
 
81

"Grinding" cavities in polyurethane foam  

Science.gov (United States)

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

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

1980-01-01

82

Grinding Parts For Automatic Welding  

Science.gov (United States)

Rollers guide grinding tool along prospective welding path. Skatelike fixture holds rotary grinder or file for machining large-diameter rings or ring segments in preparation for welding. Operator grasps handles to push rolling fixture along part. Rollers maintain precise dimensional relationship so grinding wheel cuts precise depth. Fixture-mounted grinder machines surface to quality sufficient for automatic welding; manual welding with attendant variations and distortion not necessary. Developed to enable automatic welding of parts, manual welding of which resulted in weld bead permeated with microscopic fissures.

Burley, Richard K.; Hoult, William S.

1989-01-01

83

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

Directory of Open Access Journals (Sweden)

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

Ricardo Floriano

2012-01-01

84

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

Directory of Open Access Journals (Sweden)

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

Ricardo Floriano

2013-02-01

85

Factors Affecting the Development of Oxide Scales on Austenitic Stainless Steels during Hot Rolling in Steckel Mills  

Science.gov (United States)

The hot rolling of austenitic stainless steels in Steckel Mills introduces particular characteristics to the development of oxides scales and surface structures. In this work, the formation of oxide structures during multipass hot rolling of 302 steel was studied under different sets of processing parameters in a laboratory system designed for the simulation of the Steckel process. The resulting surface structures were characterized by a set of complementary techniques involving scanning electron microscopy, energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and glow discharge optical spectroscopy (GDOS). The surface analysis revealed two alternative surface structures: one consisting in a thin protective oxide layer rich in Cr2O3 and the other consisting in thick complex structures containing several successive nonprotective oxide scale and metal layers resulting from a cyclic oxidation pattern involving stages of protective oxidation, chemical breakaway, and duplex oxidation. The critical condition that determined the activation of one mechanism or the other was identified associated with the parabolic rate constant for Cr2O3 growth and the diffusivity of Cr in the alloy. The effects of changes in temperature, deformation, and furnace atmosphere are discussed. Alternatives for controlling scale development are presented.

Cobo, S. J.; Rainforth, W. M.

2008-10-01

86

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

Scientific Electronic Library Online (English)

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

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

2013-02-01

87

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.)

88

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

89

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

Directory of Open Access Journals (Sweden)

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

Jeetendra Mohan Khare

2013-04-01

90

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

91

Tool grinding machine  

Science.gov (United States)

The present invention relates to an improved tool grinding mechanism for grinding single point diamond cutting tools to precise roundness and radius specifications. The present invention utilizes a tool holder which is longitudinally displaced with respect to the remainder of the grinding system due to contact of the tool with the grinding surface with this displacement being monitored so that any variation in the grinding of the cutting surface such as caused by crystal orientation or tool thickness may be compensated for during the grinding operation to assure the attainment of the desired cutting tool face specifications.

Dial, Sr., Charles E. (Lenoir City, TN)

1980-01-01

92

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  

Directory of Open Access Journals (Sweden)

Full Text Available 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 relation between the microstructure of the roll and the process of its tribological wear. The following was ascertained: micro-shrinkages or graphite precipitations nearby the working area cause cracks between those places and the working area; in the surface layer, cracks occur usually in the zone of ledeburitic cementite. At places of considerable precipitations of ledeburitic cementite, the tribological wear intensity of the roll is lower. A banded layout of precipitations of ledeburitic cementite facilitates a selective spalling of some parts of the roll material. The results of this study allow broadening the data base related to the effect of the microstructure on tribological wear of mill rolls, which in future will permit one to design their proper microstructure of cast iron mill rolls.

J. Krawczyk

2008-07-01

93

Thermal effects in grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The nature of grinding burn in steels and its relation to workpiece temperature has been studied in surface grinding using a new experimental approach. First, a test method called taper grinding is developed for efficiently analyzing the effects of grinding process parameters. The method is applied to study forces, residual stress, hardness, temperatures, and the onset and evolution of burn. Second, by using nano-indentation on taper-sectioned ground surfaces, an accurate assessment has been ...

Kompella, Sridhar

2002-01-01

94

Utilisation of chip thickness models in grinding  

Science.gov (United States)

Grinding is now a well established process utilised for both stock removal and finish applications. Although significant research is performed in this field, grinding still experiences problems with burn and high forces which can lead to poor quality components and damage to equipment. This generally occurs in grinding when the process deviates from its safe working conditions. In milling, chip thickness parameters are utilised to predict and maintain process outputs leading to improved control of the process. This thesis looks to further the knowledge of the relationship between chip thickness and the grinding process outputs to provide an increased predictive and maintenance modelling capability. Machining trials were undertaken using different chip thickness parameters to understand how these affect the process outputs. The chip thickness parameters were maintained at different grinding wheel diameters for a constant productivity process to determine the impact of chip thickness at a constant material removal rate.. Additional testing using a modified pin on disc test rig was performed to provide further information on process variables. The different chip thickness parameters provide control of different process outputs in the grinding process. These relationships can be described using contact layer theory and heat flux partitioning. The contact layer is defined as the immediate layer beneath the contact arc at the wheel workpiece interface. The size of the layer governs the force experienced during the process. The rate of contact layer removal directly impacts the net power required from the system. It was also found that the specific grinding energy of a process is more dependent on the productivity of a grinding process rather than the value of chip thickness. Changes in chip thickness at constant material removal rate result in microscale changes in the rate of contact layer removal when compared to changes in process productivity. This is a significant piece of information in relation to specific grinding energy where conventional theory states it is primarily dependent on chip thickness..

Singleton, Roger

95

Conduit grinding apparatus  

Science.gov (United States)

A grinding apparatus for grinding the interior portion of a valve stem receiving area of a valve. The apparatus comprises a faceplate, a plurality of cams mounted to an interior face of the faceplate, a locking bolt to lock the faceplate at a predetermined position on the valve, a movable grinder and a guide tube for positioning an optical viewer proximate the area to be grinded. The apparatus can either be rotated about the valve for grinding an area of the inner diameter of a valve stem receiving area or locked at a predetermined position to grind a specific point in the receiving area.

Nachbar, Henry D. (Ballston Lake, NY); Korytkowski, Alfred S. (Scotia, NY)

1991-01-01

96

Grinding Si3N4 Powder In Si3N4 Equipment  

Science.gov (United States)

Three methods of grinding compared. Report based on study of grinding silicon nitride powder in preparation for sintering into solid ceramic material. Attrition, vibratory, and ball mills lined with reaction-bonded silicon nitride tested. Rates of reduction of particle sizes and changes in chemical compositions of powders measured so grinding efficiences and increases in impurity contents from wear of mills and media evaluated for each technique.

Herbell, Thomas P.; Freedman, Marc R.; Kiser, James D.

1989-01-01

97

Rheology of coal-water slurries prepared by the HP roll mill grinding of coal. Quarterly technical progress report No. 3, March 1--May 31, 1993  

Energy Technology Data Exchange (ETDEWEB)

By comparing the rheological behavior of Pittsburgh No. 8 coal-water slurries obtained when using the Haake RV- 12 viscometer with both the MV-II and MV-DIN sensor systems, we found that the MV-DIN sensor system performs better than the MV-11 sensor system for slurries with high solids content. For studying the effect of chemical additives on the rheology of coal-water slurries, the Triton X series of nonionic surfactants was used. The addition of these nonionic surfactants significantly reduces the viscosity of the slurries, especially at higher reagent additions (1 wt %). Those Triton X nonionic surfactants having a larger number of ethoxy groups in the molecules are more effective for reducing the viscosity of a slurry than the surfactants with a smaller number of ethoxy groups because of the hydrophilic nature of ethoxy groups. In studying the effect of the solids content in the presence of 1 wt % Triton X-405 (dry coal basis), slurry viscosity was found to increase sharply with increasing solids content. Those slurries with high solids content (66 wt % and 67 wt %) have a significant yield stess, even at an addition of 1 wt % of Triton X-405. The maximum solids content of slurries that could be used in the presence of 1 wt % Trition X-405 is 67 percent.

Fuerstenau, D.W.

1993-06-01

98

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

99

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

100

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

 
 
 
 
101

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

102

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

Directory of Open Access Journals (Sweden)

Full Text Available Possibilities for the rationalization of the wheat flour milling process using the eightroller mill on the 1M and 2M passages of the reduction system have been investigated. At the same roll gaps and under the same sieving conditions, the lower flour yield has been obtained using an eight-roller mill compared to the conventional milling system (5-8 % followed by a higher energy requirements for grinding. By decreasing the roll gap setting and increasing the upper size limit of flour in the process with the eight-roller mill it is possible to increase flour yield and therefore decrease milling energy consumption per unit mass of flour produced without deterioration of flour quality as determined by ash content. With appropriate adjustments of the processing parameters in the eight-roller milling system it is possible to achieve similar milling results to those in the conventional system, while the overall investment, energy and maintenance costs are significantly lower.

Vukmirovi? ?uro M.

2009-01-01

103

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)

104

Grinding Away Microfissures  

Science.gov (United States)

Treatment similar to dental polishing used to remove microfissures from metal parts without reworking adjacent surfaces. Any variety of abrasive tips attached to small motor used to grind spot treated. Configuration of grinding head must be compatible with configurations of motor and workpiece. Devised to eliminate spurious marks on welded parts.

Booth, Gary N.; Malinzak, R. Michael

1990-01-01

105

Grinding Wheel System  

Science.gov (United States)

A grinding wheel system includes a grinding wheel with at least one embedded sensor. The system also includes an adapter disk containing electronics that process signals produced by each embedded sensor and that transmits sensor information to a data processing platform for further processing of the transmitted information.

Malkin, Stephen (Amherst, MA); Gao, Robert (Amherst, MA); Guo, Changsheng (South Windsor, CT); Varghese, Biju (Worthington, OH); Pathare, Sumukh (Waltham, MA)

2006-01-10

106

Dry grinding with CBN wheels, the effect of structuring  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

107

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

108

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

109

Vibration-Assisted Grinding with a Newly Developed Rotary Mechanism using Induction Motor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents the analysis of mechanisms of removal in vibration-assisted grinding process. It is known that generally for machining, application of vibration helps to increase material removal rate, reduces tool wear rate and increases depth of machining. As the failure of a component originates from the surface, effect of assisted grinding is carried out on a milling machine. The machine is equipped with a grinding wheel on which small frequency vibrations are applied. The resulta...

Noel Williamson*1; Dr. Govindan P*1,

2014-01-01

110

Evaluation of ball and roller bearings restored by grinding  

Science.gov (United States)

A joint program was undertaken to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. Groups of each of these bearings were visually and dimensionally inspected for suitability for restoration. A total of 250 bearings were restored by grinding. Of this number, 30 bearings from each type were endurance tested to a TBO of 1600 hours. No bearing failures occurred related to the restoration by grinding process. The two bearing failures which occurred were due to defective rolling elements and were typical of those which may occur in new bearings. The restorable component yield to the three groups was in excess of 90 percent.

Parker, R. J.; Zaretsky, E. V.; Chen, S. M.

1976-01-01

111

Intensification of Cement Grinding with Apply Grinding Aids with Modify Effect  

Directory of Open Access Journals (Sweden)

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

Lyubov Dmitrievna Shakhova

2014-08-01

112

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

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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

113

Rolling of rods of tungsten alloyed with lanthanum  

International Nuclear Information System (INIS)

Particularities of rolling process for rods of tungsten doped alloys and the design of test-commercial rolling mill of the MK-210 type are considered. The new process using rolling mills with four-roll passes permits to manufacture products with the uniformly developed structure and high surface quality. The yield of suitable products using a wire with 1.5-2.0 mm diameter produced of rolled billets is 15% higher than that of the mill one

114

Computation of Rolling Stand Parameters by Genetic Algorithm  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

František ?urovský; Ladislav Zboray; Želmíra Ferková

2008-01-01

115

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

116

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

117

Study concerning the grinding of the glazes for porcelain obtained by fast firing  

Energy Technology Data Exchange (ETDEWEB)

In present paper there is examined the stage grinding of glazes used for glazing feldspar porcelain under conditions of advanced technology of ceramic industry. There are proposed corresponding solutions of achieving an adequate operation for each milling stage. (orig.)

Teoreanu, I. [Universitatea Politehnica, Bucharest (Romania); Dumitrache, R.L. [S.A. ARPO, Curtea de Arges (Romania)

2002-07-01

118

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%.

119

Hot rolling technology for producing high quality stainless steel at No.3 hot strip mill in Chiba works; Chiba seitetsusho daisan netsukan atsuen kojo ni okeru stainless ko no kohinshitsuka netsukan atsuen gijutsu  

Energy Technology Data Exchange (ETDEWEB)

This paper describes technologies to control cross sectional size and quality such as sheet thickness, crown and shape, and surface quality of hot rolled stainless steels, as well as the quality levels of the steels, manufactured at the No. 3 hot strip mill in Chiba Works (Chiba 3HOT) of Kawasaki Steel. The Chiba 3HOT started operation in May 1995. Dimensions, shape and quality of hot rolled stainless steel sheets produced in this mill have been improved greatly as a result of using high-accuracy response sheet thickness control, set-up control and dynamic control of high-accuracy crown and shape in a pair cross mill introduced with an on-line roll grinder, and control of flaws in edge seams. These controls have resulted in the following achievements: (1) stainless steels made of hard steel strips with high deformation and resistance were expanded of their sizes, and high-accuracy sheet thickness was achieved over the entire length of steels; (2) a high-accuracy crown and shape controlling technology for stainless steel sheets was developed to achieve low crown stably even under schedule-free operation; and (3) a technology was developed to reduce largely the edge-seam defects by using the sizing press. 10 refs., 13 figs.

Egawa, N.; Ishizuka, H.; Hiruta, T. [Kawasaki Steel Corp., Tokyo (Japan)

1998-08-01

120

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

 
 
 
 
121

Grinding kinetics and equilibrium states  

Science.gov (United States)

The temporary and permanent equilibrium occurring during the initial stage of cement grinding does not indicate the end of comminution, but rather an increased energy consumption during grinding. The constant dynamic equilibrium occurs after a long grinding period indicating the end of comminution for a given particle size. Grinding equilibrium curves can be constructed to show the stages of comminution and agglomeration for certain particle sizes.

Opoczky, L.; Farnady, F.

1984-01-01

122

Electro-chemical grinding  

Science.gov (United States)

Electro-chemical grinding technique has rotation speed control, constant feed rates, and contour control. Hypersonic engine parts of nickel alloys can be almost 100% machined, keeping tool pressure at virtual zero. Technique eliminates galling and permits constant surface finish and burr-free interrupted cutting.

Feagans, P. L.

1972-01-01

123

Grinding Wheel Profile  

Science.gov (United States)

This graphic dubbed by engineers as the 'Grinding Wheel Profile' is the detective's tool used by the Opportunity team to help them understand one of the processes that formed the interior of a rock called 'McKittrick.' Scientists are looking for clues as to how layers, grains and minerals helped create this rock, and the engineers who built the rock abrasion tool (RAT) wanted to ensure that their instrument's handiwork did not get confused with natural processes.In the original microscopic image underlaying the graphics, engineers and scientists noticed 'layers' or 'scratches' on the spherical object nicknamed 'blueberry' in the lower right part of the image. The designers of the rock abrasion tool noticed that the arc length and width of the scratches were similar to the shape and size of the rock abrasion tool's grinding wheel, which is made out of a pad of diamond teeth.The scrapes on the bottom right blueberry appear to be caused by the fact that the berry got dislodged slightly and its surface was scraped with the grinding pad. In this image, the largest yellow circle is the overall diameter of the hole ground by the rock abrasion tool and the largest yellow rectangular shape is the area of the grinding wheel bit. The smaller yellow semi-circle is the path that the center of the grinding tool follows. The orange arrow arcing around the solid yellow circle (center of grinding tool) indicates the direction that the grinding tool spins around its own center at 3,000 revolutions per minute. The tool simultaneously spins in an orbit around the center of the hole, indicated by the larger orange arrow to the left.The grinding tool is 22 millimeters (0.9 inches) in length and the actual grinding surface, which consists of the diamond pad, is 1.5 millimeters (0.06 inches) in length, indicated by the two smaller rectangles. You can see that the smaller bottom rectangle fits exactly the width of the scrape marks.The grooves on the blueberry are also the same as the curvature of the arced pathway in which the grinding tool spins.By overlaying appropriately scaled representations of the rock abrasion tool schematics, the evidence reveals a strong indication that the scrapes on the blueberry were induced by the tool, rather than caused by some natural geologic process.The two rectangular boxes in the lower left and upper middle parts of this image are 'drop outs,' where the data packets inadvertently did not make it back to Earth during the initial communications relay via the Deep Space Network antennas. The missing data packets should be resent to Earth within the next few days. Just above each of the black 'drop out' rectangles is another rectangular area filled with a cluster of smaller rectangles in different shades of gray, which are image compression artifacts.The rock abrasion tools on both Mars Exploration Rovers were supplied by Honeybee Robotics, New York, N.Y.

2004-01-01

124

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

Directory of Open Access Journals (Sweden)

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

Dragan Krasi?

1990-12-01

125

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

126

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.

2009-07-27

127

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

[EN] In the production of portland cement, grinding aids are used to improve the grinding stage and reduce the energy required to achieve the required fineness. These additives remain in the final product and they might influence the characteristics and properties of the cement, and thus, mortar and concrete. This paper presents an evaluation of two grinding-aid additives used in the production of portland cement ground in a ball mill at a laboratory stage, with suitable proportions of portla...

Ferna?ndez Luco, Luis; Dorrego, F.; Luxa?n, M. P.

2003-01-01

128

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the production of portland cement, grinding aids are used to improve the grinding stage and reduce the energy required to achieve the required fineness. These additives remain in the final product and they might influence the characteristics and properties of the cement, and thus, mortar and concrete. This paper presents an evaluation of two grinding-aid additives used in the production of portland cement ground in a ball mill at a laboratory stage, with suitable proportions of portland ce...

Ferna?ndez Luco, L.; Dorrego, F.; Luxa?n, M. P.

2003-01-01

129

Increasing efficiency of cold rolling of corrosion resistant steel at mismatching roll velocities. [12Kh18N10T steel  

Energy Technology Data Exchange (ETDEWEB)

On the example of 12Kh18N10T steel rolling it is shown that 7-10% mismatching roll velocities raise the rolling efficiency, increase productivity and technological abilities of four-high mills at production of cold-rolled sheets. Scheme of the system of roll velocities mismatching control at asymmetrical rolling is presented. The comparative conditions of symmetrical and asymmetrical rolling of 0.8 x 1030 mm sheets from 12Kh18N10T steel are given.

Agishev, L.A.; Grishkov, A.I.; Fisher, A.R.; Frolov, G.I.; Kolesnikov, N.A. (Tsentral' nyj Nauchno-Issledovatel' skij Inst. Chernoj Metallurgii, Moscow (USSR))

1983-01-01

130

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

131

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

132

Manifested flatness predictions in thin strip cold rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper deals with flatness defects prediction in thin plates which appear during rolling. Their origin is the roll stack thermo-elastic deformation. The combination of the elastic deflection, the thermal crown and the roll grinding crown results in a non-parallel bite. If the transverse roll profile is not an affinity of the incoming strip profile, differential elongation results and induces high stresses in the outgoing strip. The latter combine with the imposed strip tension force, resul...

Abdelkhalek, Sami; Montmitonnet, Pierre; Legrand, Nicolas; Buessler, Pascal

2008-01-01

133

Grinding Inside A Toroidal Cavity  

Science.gov (United States)

Weld lines ground smooth within about 0.001 in. Grinding tool for smoothing longitudinal weld lines inside toroidal cavity includes curved tunnel jig to guide grinding "mouse" along weld line. Curvature of tunnel jig matched to shape of toroid so grinding ball in mouse follows circular arc of correct radius as mouse is pushed along tunnel. Tool enables precise control of grindout shape, yet easy to use.

Mayer, Walter; Adams, James F.; Burley, Richard K.

1987-01-01

134

Analysis of the behavior of grinding wheels in surface grinding  

Science.gov (United States)

Grinding is a machining process in which metal removal takes place through the action on the workpiece of hard abrasive particles which are attached to the grinding wheel by a bond. The abrasive grains are sharp and irregular tiny particles with several cutting edges. The material removed from the workpiece has the shape of very small chips. The random nature of the distribution of cutting edges on the surface of the wheel and its changing layout produced by wear, makes it difficult to study the cutting mechanism of abrasive grains. The optimal selection of the grinding wheel, which is the cutting tool in grinding processes, improves some key aspects of the process, such as productivity, roughness, thermal damage, tool-life... The aim of this study is to determine a methodology in order to analyze and compare the performance of different grinding wheels for the same application.

Fernández, R.; Iriarte, A.; Puerto, P.; Gallego, I.; Arrazola, P. J.

2012-04-01

135

Study on Spindle System Static and Dynamic Characteristic in Grinding Head Based on Finite Element Analysis  

Directory of Open Access Journals (Sweden)

Full Text Available With the spindle system of M8400A type roll grinding machine as the object of the research. On the basis of the establishment of the three-dimensional solid model of the roll grinder grinding head spindle system, carry out finite element static analysis, with the spindle structural stress and strain diagram, study its static characteristics, carry out modal analysis in the properly simplified spindle system with the finite element method, analyze the calculated natural frequency value, study dynamic characteristics of the spindle system, lay the foundation for the realization of the dynamic design of product.

Jin-Ling Cao

2013-01-01

136

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

137

Parametric evaluation of ball milling of SiC in water  

Science.gov (United States)

A statistically designed experiment was conducted to determine optimum conditions for ball milling alpha-SiC in water. The influence of pH adjustment, volume percent solids loading, and mill rotational speed on grinding effectiveness was examined. An equation defining the effect of those milling variables on specific surface area was obtained. The volume percent solids loading of the slurry had the greatest influence on the grinding effectiveness in terms of increase in specific surface area. As grinding effectiveness improved, mill and media wear also increased. Contamination was minimized by use of sintered alpha-SiC milling hardware.

Kiser, J. D.; Herbell, T. P.; Freedman, M. R.

1985-01-01

138

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

139

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

140

THE CHARACTERIZATION OF GRINDING FORCES  

Directory of Open Access Journals (Sweden)

Full Text Available Traditionally the grinding process has been a finishing process and the operating parameters and the resuns obtained in this mode are well known. However, wHh the advent of more modern techniques in grinding, there is a need for a greater understanding of the process and in particular a need to be able to predict the forces in grinding. The work reported here is part of an overall programme to study the effects of different dress leads, wheel formulations and metal removal rates on grinding ratios, surlace finish and grinding forces. The work so far has led to the development of empirical relationships based on the various factors in the dressing and grinding operations, these empirical relationships are more easily applied than the relationships developed by other researchers that rely on measurements obtained during testing. The work is now being extended to develop a theoretical derivation on the same principles, the implications of which will be discussed in the paper.

E.F. Fielding

2012-01-01

 
 
 
 
141

Aspects in grinding of ceramics  

International Nuclear Information System (INIS)

Aspects in the grinding of ceramics have been investigated. Si3N4, ZrO2, SiC, and Al2O3 were ground with resin-bonded diamond wheels of grit numbers ranging from 80 to 800. Microstructural observations of ground surfaces show that grinding occurs predominantly by flow mode in Si3N4 and ZrO2, and by fracture and grain pullout in SiC and Al2O3. The measurement of grinding force shows that grinding resistances in Si3N4 and ZrO2 are significantly larger than those in SiC and Al2O3. As the grit number of the grinding wheel increases, maximum surface roughness significantly decreases in Si3N4, ZrO2, and SiC, but it apparently does not change in Al2O3. This unexpected result in Al2O3 is discussed in terms of the observed grinding mode and microstructure

142

MANUFACTURE AND MARKETING MILLING FROM THE TUNGSTEN CARBIDE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Company EMO-Orodjarna in which I have carried out dissertation, produce tools for the automobile industry. In 2009 company purchased the 5-axis grinding machine for sharpening of cutting tools. The dissertation is presented how to grind mills on 5-axis grinding machine from technological and economic terms. Economic evaluation shows us that the project is rational and it will be profitable for the company.

Guzelj, Igor

2010-01-01

143

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

144

30 CFR 77.401 - Stationary grinding machines; protective devices.  

Science.gov (United States)

...2010-07-01 false Stationary grinding machines; protective devices. 77...Equipment § 77.401 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit...

2010-07-01

145

30 CFR 75.1723 - Stationary grinding machines; protective devices.  

Science.gov (United States)

...2010-07-01 false Stationary grinding machines; protective devices. 75...Miscellaneous § 75.1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit...

2010-07-01

146

Spray rolling aluminum alloy strip  

Energy Technology Data Exchange (ETDEWEB)

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.

McHugh, Kevin M.; Delplanque, J.-P.; Johnson, S.B.; Lavernia, E.J.; Zhou, Y.; Lin, Y

2004-10-10

147

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

148

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

149

Energy consumption reduction in Ring Rolling processes: a FEM analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

150

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

International Nuclear Information System (INIS)

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

151

Bruxism (Teeth Grinding or Clenching) (For Parents)  

Science.gov (United States)

... Lessons? Visit KidsHealth in the Classroom What Other Parents Are Reading Keeping Portions Under Control Recipe: Fruity ... to Know Bruxism (Teeth Grinding or Clenching) KidsHealth > Parents > General Health > Your Kid's Teeth > Bruxism (Teeth Grinding ...

152

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

153

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 veloci...

Sanyal, Subrata; Yavich, Dmitry; Leal, L. Gary

2000-01-01

154

Surface Grinding Machine Stability Characteristics Limited Prediction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 th...

Yuting Yang; Jianzhong Lin; Shilong Xu

2012-01-01

155

Thermal aspects of grinding for surface integrity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermal aspects of grinding are analyzed in detail since it is argued that temperature controls the effect of grinding on workpiece surface integrity. Transient and steady state heat partition in sliding contact is discussed in detail. This leads to a complete thermal model for heat partition and temperatures in surface grinding. Numerical predictions of the model are shown to agree with experimental results available in the literature. Effects of grinding conditions including real contact ar...

Ju, Yongqing

1997-01-01

156

Ceramic-bonded abrasive grinding tools  

Science.gov (United States)

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

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

1994-01-01

157

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

158

Fused silica fine grinding with low roughness  

Science.gov (United States)

Lithography-optics is one of the most complex optical systems. The fine grinding process is the most important step before polishing. Roughness and sub-surface damage (SSD) are essential outputs of fine grinding. We demonstrate the method that use fix abrasive cup tool with CNC grinding machine to complete the fine grinding process, even instead of lapping process. And experiment sample roughness can reach 23.40nm rms and Ra 18.554nm. The SSD estimate is about 2 ?m which is also smaller than commercial lapping process. The fine grinding output can satisfy the lithography optic fabrication demands and efficiently reduce the polishing time.

Dai, Lei; Gu, Yongqiang; Wu, Di

2014-08-01

159

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

160

High-speed flute grinding machine for twist drills and similar fluted tools  

Energy Technology Data Exchange (ETDEWEB)

The manufacturing techniques of fluted machining tools currently used are either flute milling or non-cutting processes. The increasing diversity in the range of drilling tools forces the development of a new technology. The design of tools must increase their efficiency, precision and their specific application. When applying the high speed grinding technique with cutting rates of up to 100 m/s peripheral wheel speeds, a technology can be developed which exceeds the machining performance of the so far known milling process by 15 times. The target of the project is to be seen in the development of a grinding machine for flute and body clearance grinding of twist drills and similar fluted tools. With the application of the high speed grinding technique the machining time will be reduced. With the aid of a computer supported tool design, the setting data for the machine will be processed and thus the setting-up times reduced. The objective of the development work has to be seen in the realization of a flute and body clearance grinding machine offering short machning times and flexibility with regard to setting-up.

Alber, P.; Schweizer, G.; Guehring, K.; Seit, H.

1981-01-01

 
 
 
 
161

A study of grinding characteristic of ferrule  

International Nuclear Information System (INIS)

As recently optical communication industry is developed, request of optical communication part is increased. Ferrule is very important part which determines transmission efficiency and quality of information in the optical communication part. Most of ferrule processes are grinding which request high processing precision. Particularly, concentricity and cylindricity of inner and outer diameter is very important. The co-axle grinding process of ferrule is to make its concentricity all of uniform before centerless grinding. Surface integrity of ferrule is affected by kind of grinding wheels, grinding conditions, and characteristic of workpiece and equipment. In this study, surface integrity of workpiece according to change of grinding wheel speed, feed rate, regulating wheel speed and grinding force is investigate to improve the concentricity and roundness of ferrule from many experiments

162

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

Energy Technology Data Exchange (ETDEWEB)

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)

Karimi Taheri, A.; Serajzadeh, S. [Sharif University of Technology, Dept. of Material Science and Engineering, Tehran (Iran, Islamic Republic of); Shahriari, M.A.; Izadi, J.; Fattahi, M. [Mobarake Steel Complex, Isfehan (Iran, Islamic Republic of)

2000-07-01

163

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)

164

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

165

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

Energy Technology Data Exchange (ETDEWEB)

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.

Ryu, Jae Hwa; Ryu, Han Bin [Pohang Iron and Steel Co., Ltd., Pohang (Korea, Republic of)

1998-04-01

166

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

167

Method for grinding precision components  

Science.gov (United States)

A method for precision cylindrical grinding of hard brittle materials, such as ceramics or glass and composites comprising ceramics or glass, provides material removal rates as high as 19-380 cm.sup.3 /min/cm. The abrasive tools used in the method comprise a strong, light weight wheel core bonded to a continuous rim of abrasive segments containing superabrasive grain in a dense metal bond matrix.

Ramanath, Srinivasan (Holden, MA); Kuo, Shih Yee (Westboro, MA); Williston, William H. (Holden, MA); Buljan, Sergej-Tomislav (Acton, MA)

2000-01-01

168

Spray Rolling Aluminum Strip for Transportation Applications  

Energy Technology Data Exchange (ETDEWEB)

Spray rolling is a novel strip casting technology in which molten aluminum alloy is atomized and deposited into the roll gap of mill rolls to produce aluminum strip. A combined experimental/modeling approach has been followed in developing this technology with active participation from industry. The feasibility of this technology has been demonstrated at the laboratory scale and it is currently being scaled-up. This paper provides an overview of the process and compares the microstructure and properties of spray-rolled 2124 aluminum alloy with commercial ingot-processed material

Kevin M. McHugh; Y. Lin; Y. Zhou; E. J. Lavernia; J.-P. Delplanque; S. B. Johnson

2005-02-01

169

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

Science.gov (United States)

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

Nadolny, Krzysztof

2012-09-01

170

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 stress 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 ...

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

2002-01-01

171

High efficiency classifiers for coal mills  

Energy Technology Data Exchange (ETDEWEB)

A Spanish cement company, Cementos del Mar, has recently installed a Sturtevant high efficiency airswept air classifier within a coal grinding installation at its Alcanar works. This resulted in improved mill through-puts of at least 15 per cent. The article describes the installation of the classifier and presents results of improvements in performance in the coal mill after its operation. 4 figs., 3 tabs., 2 photos.

1992-07-01

172

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

In many industries the demand for very fine material increases. In the metallurgical industry, for example, there is increasing use of the production of high density metal elements with the use of metallurgical powder composites. The use of powder composites requires prior their grinding. Unfortunately, the very fine grinding is not an easy process. The using for this purpose fluidized-bed jet mill was proposed in the paper. The attempts of grinding of metallurgical powder were carried out in...

Urbaniak, D.; Kolmasiak, C.; Wylecia?, T.

2015-01-01

173

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

174

Process engineering with planetary ball mills.  

Science.gov (United States)

Planetary ball mills are well known and used for particle size reduction on laboratory and pilot scales for decades while during the last few years the application of planetary ball mills has extended to mechanochemical approaches. Processes inside planetary ball mills are complex and strongly depend on the processed material and synthesis and, thus, the optimum milling conditions have to be assessed for each individual system. The present review focuses on the insight into several parameters like properties of grinding balls, the filling ratio or revolution speed. It gives examples of the aspects of grinding and illustrates some general guidelines to follow for modelling processes in planetary ball mills in terms of refinement, synthesis' yield and contamination from wear. The amount of energy transferred from the milling tools to the powder is significant and hardly measurable for processes in planetary ball mills. Thus numerical simulations based on a discrete-element-method are used to describe the energy transfer to give an adequate description of the process by correlation with experiments. The simulations illustrate the effect of the geometry of planetary ball mills on the energy entry. In addition the imaging of motion patterns inside a planetary ball mill from simulations and video recordings is shown. PMID:23389051

Burmeister, Christine Friederike; Kwade, Arno

2013-09-21

175

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

176

Rolling Robot  

Science.gov (United States)

Proposed rolling robot routinely traverses rough terrain, clearing rocks as high as 1 m. Climbs steps 1 m high and spans ditches 2.3 m wide. Simple but rugged semiautonomous rover has large wheels and articulated body. With combined yaw, roll, and four-wheel drive, robot crawls slowly to pass over soft or sandy terrain. Senses terrain along corridor, chooses path to avoid insurmountable obstacles, and monitors state of vehicle for unexpected hazards.

Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.

1990-01-01

177

30 CFR 75.1723 - Stationary grinding machines; protective devices.  

Science.gov (United States)

...2010-07-01 2010-07-01 false Stationary grinding machines; protective devices...MINES Miscellaneous § 75.1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than...

2010-07-01

178

30 CFR 77.401 - Stationary grinding machines; protective devices.  

Science.gov (United States)

...2010-07-01 2010-07-01 false Stationary grinding machines; protective devices...Mechanical Equipment § 77.401 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than...

2010-07-01

179

30 CFR 57.14115 - Stationary grinding machines.  

Science.gov (United States)

... 2010-07-01 2010-07-01 false Stationary grinding machines. 57.14115 Section...and Maintenance Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit...

2010-07-01

180

30 CFR 56.14115 - Stationary grinding machines.  

Science.gov (United States)

... 2010-07-01 2010-07-01 false Stationary grinding machines. 56.14115 Section...and Maintenance Requirements § 56.14115 Stationary grinding machines. Stationary grinding machines, other than special bit...

2010-07-01

 
 
 
 
181

30 CFR 56.14115 - Stationary grinding machines.  

Science.gov (United States)

...2010-07-01 2010-07-01 false Stationary grinding machines. 56.14115 Section 56.14115 Mineral...Requirements § 56.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall...

2010-07-01

182

30 CFR 57.14115 - Stationary grinding machines.  

Science.gov (United States)

...2010-07-01 2010-07-01 false Stationary grinding machines. 57.14115 Section 57.14115 Mineral...Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall...

2010-07-01

183

Thermal modeling of grinding for process optimization and durability improvements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 triangu...

Hanna, Ihab M.

2006-01-01

184

Grinding machine: friend or foe.  

Science.gov (United States)

Few cases of traumatic loses of the external genitalia have been reported in this part of the world. In a developing country like ours, grinding machines are commonly being used by the people for domestic purposes. Children in their mid fifteens are usually employed to man and operate the machine without proper training and apprenticeship. Many of them have fallen victims of various genito-urinary injuries from grinding machine. Treating a child for complete traumatic loss of penis is rare and challenging any where in the world. A 12 years old boy presented to the emergency unit of our hospital with penile amputation 18 hours after the injury was sustained. A penile reconstruction of corporal cavernosa phalloplasty was used. This method of reconstruction may be used by clinician in our sub-region where other treatment modalities such as replantation by microvascular surgery, use of free radial fore-arm flap or sex reassignment to the female gender may not be feasible or acceptable. PMID:12665282

Adigun, I A; Kuranga, S A; Abdulrahman, L O

2002-01-01

185

Lathe converted for grinding aspheric surfaces  

Science.gov (United States)

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

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

1964-01-01

186

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

187

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

188

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

189

The effect of processing parameters on energy consumption of ball mill refiner for chocolate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A laboratory ball mill consisting of vertical cylinder, equipped with a rotating shaft with arms, and filled with steel balls as a grinding medium has been used in the experiments. The aim of the study was to examine the effect of agitator shaft speed and amount of grinding media (steel balls) on power requirements and energy consumption of a ball mill. With constant mass of the steel balls (20 kg, 30 kg and 40 kg), the agitator shaft speed was increased fr...

Fišteš Aleksandar Z.; Raki? Dušan Z.; Pajin Biljana S.; Doki? Ljubica P.; Nikoli? Ivana R.

2013-01-01

190

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

191

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

192

40 CFR 63.1341 - Definitions.  

Science.gov (United States)

...product. Finish mill means a roll crusher, ball and tube mill or other size reduction equipment used to grind...the moisture content of feed materials. Raw mill means a ball and tube mill, vertical roller mill or other size...

2010-07-01

193

Modelling the vertical spincasting of large bimettalic rolling mill rolls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to take into account the dynamic effects of molten metal during solidification, a methodology is presented to interface a metal solidification solver with a specifically developped flow dynamics solver.

Studer, Le?o; Detrembleur, Sylvain; Habraken, Anne; Pirotton, Michel; Pascon, Fre?de?ric; Dewals, Benjamin

2008-01-01

194

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

International Nuclear Information System (INIS)

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

195

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

196

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 stress 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

2002-06-01

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

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

Directory of Open Access Journals (Sweden)

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

D. Urbaniak

2015-01-01

199

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

200

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

 
 
 
 
201

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)

202

Effects of dry grinding on pyrolliphyte  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dry grinding of pyrophyllite (Hillsboro, USA) has been studied by X-ray diffraction (XRD), specific surface area measurements (BET) and scanning electron microscopy (SEM). At the beginning of the grinding process, some effects such as delamination, gliding and folding of the layers, and decrease in particle size were detected by SEM and XRD, resulting in a large increase in specific surface area, up to a maximum of ~ 60 m 2 . g-1. Marked changes in the structure take place betw...

Pe?rez Rodri?guez, Jose? Luis; Madrid, Luis; Sa?nchez-soto, Pedro Jose?

1988-01-01

203

Temperatures in high efficiency deep grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This research considers the temperatures generated in the workpiece during profile and cylindrical traverse grinding in the High Efficiency Deep Grinding (HEDG) regime. The HEDG regime takes large depths of cut at high wheel and workpiece speeds to create a highly efficient material removal process. This aggressive processing generates high temperatures in the contact zone between the wheel and workpiece. However, the beneficial contact angle and the rapid removal of the heated wheel – work...

Bell, Andrew John

2009-01-01

204

Cylindricity control in precision centerless grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A computer simulation method for investigating the form generation mechanism in the centerless grinding process is described. In this work, instantaneous change of the apparent depth of cut during grinding was modeled using absolute coordinate systems. The result of the simulation was not affected by the coordinate system (the location of the reference circle center and the radius of the reference circle). Also, analytical models of the interference phenomena at the contact points were develo...

Kim, Kang

1992-01-01

205

Critical study of high efficiency deep grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 experim...

Johnstone, Lain

2002-01-01

206

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

207

Delamination of hexagonal boron nitride in a stirred media mill  

International Nuclear Information System (INIS)

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

208

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

Science.gov (United States)

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.

He, R. Y.; Liu, J.; Yuan, Y. L.; Shao, Y. M.; Xiao, H. F.

2012-05-01

209

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.

210

Kommunikatsiooni roll kiirelt muutuvas maailmas / Susan Lilleväli, Marit Priks  

Index Scriptorium Estoniae

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

Lilleväli, Susan

2014-01-01

211

Studying possibilities to improve the functional properties of metallurgical rolls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

212

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

213

High-speed milling of light metals  

Directory of Open Access Journals (Sweden)

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

F. Cus

2007-01-01

214

Differential comminution of gypsum in cements ground in different mills  

International Nuclear Information System (INIS)

Identical mixes containing fixed amounts of ordinary Portland cement clinker and gypsum were ground in two types of industrial cement mills - viz. ball mill (BM) and vertical roller mill (VRM) - to identical Blaine fineness to examine the effect of any possible differential comminution of gypsum on cement setting times. The present investigation demonstrates that during comminution of cements, the degree of crystallinity of gypsum, as determined by X-ray diffraction (XRD), changes with used grinding mills and this causes changes in setting times of similar cements even when ground to identical Blaine fineness

215

Grinding technologies of small optical element molds  

Science.gov (United States)

The high-precision grinding technology is making contribution in every field, which is especially remarkable in the optics-related field. Lenses for digital camera and projector, which are mass-produced, for instance, are molded by the injection molding machine and glass molding-press machine. Concerning materials of high-precision molds, nickel alloy is mainly used in plastic-molding. And brittle material such as tungsten carbide and ceramic is used in glass-molding because the molding temperature is generally high. High-precision machining of nickel alloy is possible with a single-crystal diamond tool. Brittle material is ground by means of a diamond wheel, etc. Glass is being widely used for the lenses and other optical elements due to its favorable characteristics and life. As a result, needs for advancement of the high-precision grinding technology are being heightened. In grinding of small, fine and complex profiles, consideration for wheel truing and wear is a key point. Also, as many optical mold products are convex, mold profile is mainly concave. Especially, grinding of a small-aperture mold with small radius of curvature is difficult. In other words, a wheel whose diameter is larger than the radius of curvature of a mold to be ground cannot be used, and use of a small-diameter wheel is required inevitably. Influence of wheel wear and wheel diameter input errors at creation of grinding program becomes large. To eliminate such errors, a cycle of grinding, measurement and compensation grinding is normally repeated in mold machining until the target accuracy is obtained. Recently, needs for molding optical elements of small body of non-revolution such as prism and cylinder lens are on the increase, in addition to the body of revolution including lens. As one example, we introduce the compensation grinding and its results when grinding molds for an extremely small-aperture lens used for optical communication and a cylindrical lens array used for semi-conductor laser correction.

Katsuki, Masahide; Urushibata, Kazunori

2003-05-01

216

Monitoring of surface burn after grinding larger bearing rings  

Science.gov (United States)

This paper deals with detection of surface burn after grinding of larger bearing rings made of case - hardened steels. The paper reports about calibration of Barkhausen noise technique for non destructive monitoring of grinding operations for rings of diameter in the range of 600 up to 4000 mm. Properly suggested monitoring concept enables to detect thermal damage due to grinding wheel wear as well as insufficient coolant supply. Further, grinding burn associated with lack of coolant can be clearly distinguished from damage corresponding grinding wheel wear. The paper also discusses increasing magnetoelastic responses obtained after grinding rings of higher diameters.

Neslušan, M.; Mi?ietová, A.; ?illiková, M.

2014-02-01

217

Factors influencing the ball milling of Si3N4 in water  

Science.gov (United States)

A statistical study of the ball milling of Si3N4 powder in Si3N4 hardware was undertaken to understand how the resulting increase in specific surface area is related to solids loading and mill speed. An attempt was made to optimize milling conditions. The degree of communication was more dependent upon solids loading than mill speed. A practical grinding limit between 0.5 and 0.75 microns was achieved in 144 hr independent of solids loading. Ball mill wear and media wear were independent of both solids loading and mill speed.

Freedman, M. R.; Kiser, J. D.; Herbell, T. P.

1985-01-01

218

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)

219

Modeling of the process of coal grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 analy...

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

2013-01-01

220

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

 
 
 
 
221

A new sensor for the evaluation of contact stress by inverse analysis during steel strip rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Knowledge of the contact stress between roll and strip becomes a critical factor in modern, high-speed rolling mills. In this paper, an inverse analytical method is developed to determine the contact stress in the roll gap by measuring the stress tensor with fibre optics at only one point inside the roll. Unlike many inverse methods, no matrix inversion is needed because the very small contact length would lead to ill-conditioned matrices. Iterative methods are also not studied because short ...

Weisz-patrault, Daniel; Ehrlacher, Alain

2011-01-01

222

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

223

KINEMATICS OF MATERIAL REMOVAL AND FORMING OF SURFACE AT GRINDING  

Directory of Open Access Journals (Sweden)

Full Text Available The mathematical model of kinematics of material removal and a forming of surfaces isdeveloped at grinding. Conditions of increase of productivity of processing are defined and newkinematic schemes of high-performance grinding are offered

Feodor NOVIKOV

2013-05-01

224

KINEMATICS OF MATERIAL REMOVAL AND FORMING OF SURFACE AT GRINDING  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The mathematical model of kinematics of material removal and a forming of surfaces isdeveloped at grinding. Conditions of increase of productivity of processing are defined and newkinematic schemes of high-performance grinding are offered

Novikov, Feodor

2013-01-01

225

The flexible grinding technology based on the electric current control  

Science.gov (United States)

A flexible grinding technology based on the electric current control is presented to resolve the problem of low rigidity of PCB during grinding, the thickness of which varies from 0.1mm up to 3.5 mm. The comparative results between the real-time current and the setting current in the process of grinding control the frequency and the number of servo pulse, and then the servo motor adjusts the grinding depth of brushing roller at several different rotational speeds, namely, realizing the constant grinding force during grinding. The results show that the PCB can be grinded efficiently and accurately by means of the flexible grinding technology based on the electric current control.

Peng, Liwen; Yao, Bin; Li, Fei; Wang, Xiao; Yao, Boshi

2012-01-01

226

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...

227

Poplar stump grinding: analysis of work time and costs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Poplar stump grinding: analysis of work time and costs. After harvesting and extracting poplar trees, the agricultural land should be restored for further cultivation by removing the root systems. This operation is done with extraction or stumps grinding using special machines. In Italy, the stumps grinding is actually the operation more practiced. This paper deals with an analysis of work time, productivity and costs of the poplar stumps grinding, performed by two different operators. The po...

Sperandio G; Verani S

2012-01-01

228

Energy-force conditions for rolling of titanium alloys in cross-shaped tetraroll calibers  

International Nuclear Information System (INIS)

In case of rolling high-strength titanium alloys VT14, VT9, VT8 the metal pressure upon the rolls is 1.5 - 2 times more than in case of rolling VT5, OT4 alloys of a medium strength and 3-4 times more than in case of rolling VTI-0 technical titanium. The results obtained may be employed for the determination of methods of thin-wall profile rolling as well as for designing mills with multi-roll passes

229

7 CFR 58.726 - Cutting and grinding.  

Science.gov (United States)

... 2010-01-01 false Cutting and grinding. 58.726 Section 58.726 Agriculture...Procedures § 58.726 Cutting and grinding. The trimmed and cleaned cheese...handled by the grinder or shredder. The grinding and mixing of the blended lots of...

2010-01-01

230

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

231

Automated Inspection And Precise Grinding Of Gears  

Science.gov (United States)

Method of precise grinding of spiral bevel gears involves automated inspection of gear-tooth surfaces followed by adjustments of machine-tool settings to minimize differences between actual and nominal surfaces. Similar to method described in "Computerized Inspection of Gear-Tooth Surfaces" (LEW-15736). Yields gears of higher quality, with significant reduction in manufacturing and inspection time.

Frint, Harold; Glasow, Warren

1995-01-01

232

Carving up Word Meaning: Portioning and Grinding  

Science.gov (United States)

Two eye-tracking experiments investigated the processing of mass nouns used as count nouns and count nouns used as mass nouns. Following Copestake and Briscoe (1995), the basic or underived sense of a word was treated as the input to a derivational rule (''grinding'' or ''portioning'') which produced the derived sense as output. It was…

Frisson, S.; Frazier, L.

2005-01-01

233

Precision replenishable grinding tool and manufacturing process  

Science.gov (United States)

A reusable grinding tool consisting of a replaceable single layer of abrasive particles intimately bonded to a precisely configured tool substrate, and a process for manufacturing the grinding tool. The tool substrate may be ceramic or metal and the abrasive particles are preferably diamond, but may be cubic boron nitride. The manufacturing process involves: coating a configured tool substrate with layers of metals, such as titanium, copper and titanium, by physical vapor deposition (PVD); applying the abrasive particles to the coated surface by a slurry technique; and brazing the abrasive particles to the tool substrate by alloying the metal layers. The precision control of the composition and thickness of the metal layers enables the bonding of a single layer or several layers of micron size abrasive particles to the tool surface. By the incorporation of an easily dissolved metal layer in the composition such allows the removal and replacement of the abrasive particles, thereby providing a process for replenishing a precisely machined grinding tool with fine abrasive particles, thus greatly reducing costs as compared to replacing expensive grinding tools.

Makowiecki, Daniel M. (Livermore, CA); Kerns, John A. (Livermore, CA); Blaedel, Kenneth L. (Livermore, CA); Colella, Nicholas J. (Livermore, CA); Davis, Pete J. (Pleasanton, CA); Juntz, Robert S. (Hayward, CA)

1998-01-01

234

Grinding Glass Disks On A Belt Sander  

Science.gov (United States)

Small machine attached to table-top belt sander makes possible to use belt sander to grind glass disk quickly to specified diameter within tolerance of about plus or minus 0.002 in. Intended to be used in place of production-shop glass grinder. Held on driveshaft by vacuum, glass disk rotated while periphery ground by continuous sanding belt.

Lyons, James J., III

1995-01-01

235

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

236

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

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english 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

237

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

238

Cross Shear Roll Bonding  

DEFF Research Database (Denmark)

The present paper describes an investigation of roll bonding an AlZn alloy to mild steel. Application of cross shear roll bonding, where the two equal sized rolls run with different peripheral speed, is shown to give better bond strength than conventional roll bonding. Improvements of up to 20-23% in bond strength are found and full bond strength is obtained at a reduction of 50% whereas 65% is required in case of conventional roll bonding. Pseudo cross shear roll bonding, where the cross shear effect is obtained by running two equal sized rolls with different speed, gives the same results.

Bay, Niels; Bjerregaard, Henrik

1994-01-01

239

Mathematical Aspect for Worm Grinding Using a Toroidal Tool  

Directory of Open Access Journals (Sweden)

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

Tareq A. Abu Shreehah

2004-01-01

240

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

 
 
 
 
241

Controlled rolling of profiles  

International Nuclear Information System (INIS)

The effect is investigated of various temperatures and deformation rates in the course of rolling of steels, of the 40Kh steel in particular, upon the power rating and the energy requirements, the roll wear and mechanical properties of finished rolled stock. It is found that a lowering of the rolling temperature to 950-850 deg C has improved the properties of the finished rolled stock (greater strength without reducing the plasticity)

242

Functionalization of glassy carbon spheres by ball milling of aryl diazonium salts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Solvent free derivatization has been achieved by a simple ball mill grinding procedure to functionalize glassy carbon spheres with anthraquinonyl and nitrophenyl groups using aryl diazonium salts. Grinding facilitates the mechanical activation of the carbon substrate material with the creation of active centres and may induce the decomposition of the diazonium salt. The functionalized glassy carbon spheres were characterized electrochemically by studying their cyclic voltammetry. These modifi...

Pandurangappa, M.; Ramakrishnappa, T.; Compton, Rg

2009-01-01

243

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)

244

Dressing of fine grained diamond grinding wheels for ultra precision grinding of structured molds in brittle hard materials  

Science.gov (United States)

The manufacturing of structured molds calls for alternatives in terms of grinding wheel geometry and dressing. To manufacture geometric features in the micron range on molds, sharp edged fine grained grinding wheels can be used. A dressing procedure with metal alloy blocks is used to create sharp edged grinding wheels. This paper presents results and achieved tip radii of dressed resin bonded and metal bonded grinding wheels. Furthermore, a grinding test on a tungsten carbide mold is carried out to create a diffractive structure and the achieved form accuracy and surface roughness are presented.

Bletek, Thomas; Klocke, Fritz; Hünten, Martin; Dambon, Olaf

2013-09-01

245

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

246

Development of dissimilar metal transition joint by hot bond rolling  

International Nuclear Information System (INIS)

Metallurgically bonded transition joints which enable to connect reprocessing equipments made of superior corrosion resistant valve metals (Ti-5Ta, Zr or Ti) to stainless steel piping are required for nuclear fuel reprocessing plants. The authors have developed dissimilar transition joints made of stainless steel and Ti-5Ta, Zr or Ti with an insert metal of Ta by the hot bond rolling process of clad bars and clad pipes, using a newly developed mill called 'rotary reduction mill'. This report presents the manufacturing process of dissimilar transition joints produced from the clad pipe with three layers by the hot bond rolling. First, the method of hot bond rolling of clad pipe is proposed. Then, the mechanical and corrosion properties of the dissimilar transition joints are evaluated in detail by carrying out various tests. Finally, the rolling properties in the clad pipe method are discussed. (author)

247

First Grinding of a Rock on Mars  

Science.gov (United States)

The round, shallow depression in this image resulted from history's first grinding of a rock on Mars. The rock abrasion tool on NASA's Spirit rover ground off the surface of a patch 45.5 millimeters (1.8 inches) in diameter on a rock called Adirondack during Spirit's 34th sol on Mars, Feb. 6, 2004. The hole is 2.65 millimeters (0.1 inch) deep, exposing fresh interior material of the rock for close inspection with the rover's microscopic imager and two spectrometers on the robotic arm. This image was taken by Spirit's panoramic camera, providing a quick visual check of the success of the grinding. The rock abrasion tools on both Mars Exploration Rovers were supplied by Honeybee Robotics, New York, N.Y.

2004-01-01

248

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

249

Grinding Characteristics of Reaction Bonded Silicon Carbide  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Yao Wang, Zhang Yu-min

2012-01-01

250

Intelligent modeling and optimization of grinding processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this study is to develop and implement a methodology for modeling complex grinding processes and finding optimal process conditions to meet a general class of process requirements. In order to achieve these goals, novel modeling schemes and optimization methods based on fuzzy logic, neural networks, and evolutionary algorithms (EA) are developed. ^ A hierarchical structure which consists of radial basis function networks (RBFN), fuzzy basis function networks (FBFN), and ana...

Lee, Cheol Won

2000-01-01

251

Vibration syndrome and vibration in pedestal grinding.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1983-01-01

252

Precision grinding of micro-aspherical surface  

Science.gov (United States)

Recently, micro aspherical glass lenses are required for electric devices, optical devices and advanced optical fiber transmission equipments. The glass lenses are manufactured with glass molding method by using ceramics dies such as tungsten carbide and therefore molding dies are most important. The ceramics molding dies must be ground ultra-precisely with micro diamond wheel. In this report, our developed micro grinding methods/systems are discussed according to a variety of the workpiece shapes.

Suzuki, Hirofumi; Shibutani, Hideo; Higuchi, Toshiro; Horiuchi, Osamu

2003-05-01

253

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

254

The formation of edge cracks during rolling of metal sheet  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Many metals tend to develop edge cracks during hot and cold rolling. Edge cracks need to be removed by a trimming operation, and they may cause rupture of the sheet in the rolling mill. Hence, there is a strong motivation to understand the mechanisms of edge crack formation and to develop predictive tools for controlling the phenomenon. The present work explores the applicability of damage mechanics models to this problem. In conjunction with a plausible failure criterion the Gologanu-Leblond...

Riede, H.; Andrieux, F.; Walde, T.; Karhausen, K. -f

2007-01-01

255

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)

256

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

257

Coal cleaning in a Mag-Mill  

Energy Technology Data Exchange (ETDEWEB)

Preliminary results obtained in earlier studies have established the technical feasibility of preparing low ash and low sulfur coals by employing dry magnetic separation to treat the internal circulation of air-swept pulverizers preparing pc grind coal for direct firing. The authors now report results of more recent experiments which extend the earlier work. The new studies have tested the effects of treating more of the mill`s internal circulation than was previously possible. The ParaTrap magnetic separator can be retrofitted to existing pulverizers keeping capital costs low. A preliminary engineering evaluation indicates that a 1,600 MW{sub e} power plant burning washed coal from Northern Appalachia can save as much as $4,000,000 per year by procuring raw coals and cleaning them in the Mag-Mill.

Oder, R.R.; Jamison, R.E.; Reichner, T.W. [EXPORTech Co., Inc., New Kensington, PA (United States); Davis, J.R. [Bradley Pulverizer Co., Allentown, PA (United States)

1995-12-31

258

Effect of Home Grinding on Properties of Brewed Coffee  

Directory of Open Access Journals (Sweden)

Full Text Available We present measurements of particle size distribution, density, loss of coffee on brewing and caffeine content in brewed coffee (as measured using Fourier Transform Infrared Spectroscopy as a function of grinding time using a blade-type grinder. In general, there is not a lack of correlation between coffee properties and grinding for grinding times in excess of 42 s, but mass loss on brewing and caffeine content are both increased with grinding times between 0 and 42 s. In addition, we present evidence that this dependence of the composition of brewed coffee on grinding time is a function of increased coffee particle surface area that results from grinding, rather than increased loss of grounds into the brewed beverage or increased percolation time. Finally, we present a general recommendation for determining equivalency between small amounts of finely ground coffee and larger amounts of coarser-ground coffee.

Christopher Murray

2014-10-01

259

Facial lesions in piglets with intact or grinded teeth  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Piglets are born with eight sharp teeth that during nursing can cause facial lesions on littermates and teat lesions on the sow. Teeth grinding in piglets is therefore often practiced to reduce these lesions. The aim of this study was to assess the consequences of grinding piglet teeth in regard to the occurrence of lesions. In this study the piglets' teeth were grinded in 28 litters, and in 36 litters the piglets' teeth were kept intact. Twice, one...

Hansson Monica; Lundeheim Nils

2012-01-01

260

CALCULATION OF SURFACE ROUGHNESS PARAMETERS FOR EXTERNAL CYLINDRICAL GRINDING  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The method of calculating the surface roughness parameters for an external cylindrical grinding is considered. The offered calculation relations are taken account of production mode parameters, the grain size of the grinding wheel and the change of state of the tool working surface during machining. This allows to assess the impact of multipass grinding process and to predict the kinetics of changes in surface roughness.

Bogutsky, Vladimir; Gutsalenko, Yury; Bratan, Sergey; Novoselov, Yuri

2013-01-01

 
 
 
 
261

REVIEW OF DRESSING AND TRUING OPERATIONS FOR GRINDING WHEELS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Grinding is an operation applied in almost every type of manufacturing process. It aims to produce high surface finish and to maintain close tolerances in the manufactured product. To make the grinding operation more productive and efficient, dressing and truing operations are performed on the grinding wheels. Various techniques are available and are used for the same. Since many permutations and combinations exists among the factors like economics, efficiency, accuracy, complexity, etc. of t...

UJJAWAL MAYANK SRIVASTAVA

2013-01-01

262

Fundamentals of grinding : surface conditions of ground materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis describes the research on the fundamental and physical aspects of the grinding process of hard and brittle materials. The objective of this research is to develop a physical model in order to explain and predict the change in functional properties. Besides that, such a model can be used to optimise the grinding process. Two different materials, cemented carbide and MnZn ferrite, were used in order to verify the grinding model. ... Zie: Summary

Hegeman, Johannes Bernardus Jan-willem

2000-01-01

263

In-process grinding monitoring through acoustic emission  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 syst...

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

2006-01-01

264

Global analysis of aerodynamics deflectors efficiency in the grinding process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The conventional grinding methods in some cases are not very efficient because the arising of thermal damages in the pieces is very common. Optimization methods of cutting fluid application in the grinding zone are essential to prevent thermal problems from interaction of the wheel grains with the workpiece surface. The optimization can happen through the correct selection of the cut parameters and development of devices that eliminate air layer effects generated around the grinding wheel. Th...

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

2006-01-01

265

Grinding processes and their effects on surface integrity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The introduction of high performance grinding machines in combination with the latest superabrasive technology has the potential to impact significantly on existing process chains. The aim of the research was to look at both the high and low rate removal grinding processes and their effects on the surface integrity, as a means to exploit the above technologies. A major objective was to determine the feasibility of High Efficiency Deep Grinding (HEDG) in cylindrical plunge gr...

Comley, Paul

2005-01-01

266

Development of database and searching system for tool grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 t...

Chen, J. Y.; Lin, W. Y.; Lee, B. Y.; Chen, C. H.

2008-01-01

267

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

268

Mathematical Aspect for Worm Grinding Using a Toroidal Tool  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Abu Shreehah, Tareq A.; Abdullah, Rasheed A.

2004-01-01

269

Grinding tool for making hemispherical bores in hard materials  

Science.gov (United States)

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

Duran, E.L.

1985-04-03

270

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

271

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)

272

Learning Activity Packets for Grinding Machines. Unit II--Surface Grinding.  

Science.gov (United States)

This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the second unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

273

Learning Activity Packets for Grinding Machines. Unit I--Grinding Machines.  

Science.gov (United States)

This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the first unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

274

Learning Activity Packets for Grinding Machines. Unit III--Cylindrical Grinding.  

Science.gov (United States)

This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the third unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

275

Impact resistance of guards on grinding machines.  

Science.gov (United States)

Guards on machine tools are meant to protect persons from injuries caused by parts ejected with high kinetic energy from the machine's working zone. With respect to stationary grinding machines, Standard No. EN 13218:2002, therefore, specifies minimum wall thicknesses for guards. These values are mainly based on estimations and experience instead of systematic experimental investigations. This paper shows to what extent simple impact tests with standardizable projectiles can be used as basis for the evaluation of the impact resistance of guards, provided that not only the kinetic energy of the projectiles used but also, among others, their geometry corresponds to the abrasive product fragments to be expected. PMID:22152506

Mewes, Detlef; Mewes, Olaf; Herbst, Peter

2011-01-01

276

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

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of this work was to verify the usefulness of high-energy milling, using electromagnetic mill, as a method for obtaining tetragonal (red form of PbO, alternative to standard methods.Design/methodology/approach: Experiments were held to compare samples of the yellow form of PbO after milling in electromagnetic mill with the ones milled in high-energy planetary ball mill as a function of grinding medium (sticks or balls to powder mass ratio, milling duration and instrumental conditions.Findings: Quantitative X-ray diffraction and analysis of granulation of mill products were applied. The characteristics of structural transitions of studied powder depending on milling conditions were defined.Practical implications: Utilization of electromagnetic mills was found to be suitable for milling of PbO. The speed and unit price of this process assure competitiveness of the method to standard methods. Tested method of high-energy milling assures possibility to supply, in certain conditions, good product. Obtained product may be used for manufacturing of minium.Originality/value: Optimum conditions of milling process and milling limitations were determined. Suggestions regarding optimization of mill construction were presented.

M. Staszewski

2012-05-01

277

30 CFR 56.15014 - Eye protection when operating grinding wheels.  

Science.gov (United States)

...false Eye protection when operating grinding wheels. 56.15014 Section 56...15014 Eye protection when operating grinding wheels. Face shields or goggles in...condition shall be worn when operating a grinding wheel. [53 FR 32526, Aug....

2010-07-01

278

30 CFR 57.15014 - Eye protection when operating grinding wheels.  

Science.gov (United States)

...false Eye protection when operating grinding wheels. 57.15014 Section 57...15014 Eye protection when operating grinding wheels. Face shields or goggles in...condition shall be worn when operating a grinding wheel. [53 FR 32533, Aug....

2010-07-01

279

Development of Roller Ends Forced-Contact Model and Cambering Technology for UCM Temper Mill (II)——Development of cambering technology for UCM temper mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 resea...

Zhenhua Bai; Xiaodong Shi; Hongxin Si; Linfang Han; Ruibing Long; Shoumin Wu; Xiujun Li; Dongdong Zhang

2011-01-01

280

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

 
 
 
 
281

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.

282

Converting the Key Lake mill process for McArthur River ore  

International Nuclear Information System (INIS)

The Key Lake mill was commissioned in 1983 to process the two Key Lake ore deposits. With the depletion of these ore bodies in 1999, the plant was converted to mill the exceptionally rich McArthur River deposit located seventy eight kilometers northeast of the Key Lake mine site. This paper describes in detail the Key Lake milling process. The mill consists of a grinding circuit, a leach/counter current decantation circuit, a solvent extraction circuit, a yellowcake precipitation/calciner circuit, an ammonium sulphate crystallization circuit, and a waste treatment circuit. The paper also describes process changes to handle McArthur River ore, including the ore receiving station. (author)

283

Photothermal characterization of grind-hardened steel  

Science.gov (United States)

Grind hardening is a promising production process which combines grinding and hardening within one step. Due to the fact that many material and process parameters partially influence the properties of the workpieces in a nonlinear way, it is difficult to predict for instance the surface hardness and hardness penetration depth. In this study, photothermal radiometry is used as an approach to determine the hardness penetration depth. Photothermal phase signals have been measured as a function of frequency. First measurements showed a strong influence of surface roughness, causing phase signal maxima at unexpected high frequencies (f>60 Hz). After finishing of the surfaces, the maxima of phase signals shifted toward lower frequencies (f<10 Hz). In an attempt to extract a preliminary calibration curve, the measured phase values of each sample were added and correlated to the hardness penetration depth. The resulting curve reveals a good correlation between phase sum and the hardness penetration depth. Further research is necessary to collect more experimental data and to support the current results by theoretical models.

Prekel, H.; Ament, Ch.; Goch, G.

2003-01-01

284

Effects of grinding on certain crystalline structures; Influence de broyage sur quelques structures cristallines  

Energy Technology Data Exchange (ETDEWEB)

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 ({beta}). 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) [French] Les effets du broyage sur certains corps cristallises (ZnO, ZnS, Sb) ont ete etudies a l'aide de la diffraction de rayons X et de la microscopie electronique. Les broyages ont ete effectues au moyen d'un vibro-broyeur qui met en jeu une energie superieure par rapport aux appareils plus conventionnels tels que les broyeurs a boulets. Diverses methodes concernant la determination de la largeur du profil intrinseque ({beta}) ont ete proposees. Dans le cas de l'oxyde de zinc on a montre la possibilite de differencier les contributions de l'effet de fragmentation et celui de perturbation du reseau, a l'effet total du broyage. Avec les deux varietes de sulfure de zinc (blende et Wurtzite) on a montre que le point de transformation de la blende en Wurtzite) etait fortement abaisse et que la transformation de la Wurtzite vers la forme stable (blende) a la temperature ambiante etait considerablement acceleree par le broyage. Dans le cas de l'antimoine le mode de fragmentation fait apparaitre une anisotropie qui doit etre reliee a l'existence des plans de clivage facile. Ces observations montrent que dans le cas d'un broyage effectue avec une energie suffisante, l'accumulation de cette energie dans la matiere par creation de defauts de reseau peut accelerer la vitesse de reaction ou provoquer des transformations physiques. (auteur)

Tekiz, Y. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-06-15

285

Microsurface finishing of borosilicate glass with magnetic fluid grinding  

Science.gov (United States)

A new microsurface finishing method of local area using magnetic fluid, abrasive grains and magnet is proposed. The profile of grinding surface of borosilicate glass is observed as a function of grinding time and magnetic fluid strength. Magnetic fluid and magnetic field can provide efficient and uniform finishing in a local area.

Umehara, N.; Mizuguchi, S.; Kato, K.; Nakamara, S.

1993-04-01

286

Numerical simulation in roll pass design for bar rolling  

Directory of Open Access Journals (Sweden)

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

S. A. Aksenov

2015-01-01

287

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

Directory of Open Access Journals (Sweden)

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

Isarawit Chaopanich

2010-07-01

288

Texture of yttrium rolling  

International Nuclear Information System (INIS)

Textures appearing in yttrium after rolling are studied. It is shown that the yttrium rolling textures are characterized by the prevailing location of basic planes in a parallel to the sheet plane. The increase of deformation degree and yttrium rolling temperature is accompanied by the increase of the sheet basic texture. The deformation and texture formation during yttrium rolling occur at the expense of slip concurrence in two main systems (prismatic and basic). The value of contribution of one or the other system depends on the deformation temperature, which is conditioned by the change of the ratio between critical shift stresses tausub(1010) and tausub(0001)

289

Further study on coal mill modelling for on-line implementation  

Energy Technology Data Exchange (ETDEWEB)

A mathematical model of a vertical spindle coal mill to represent a complete mill process has been developed in the authors' previous work. The paper is to investigate if there is an alternative parameter identification method suitable for on-line implementation. Particle Swarm Optimisation method has been studied and applied to coal mill model parameter identification. The coal mill model can represent the coal mill normal grinding process, which consists of 9 equations and 16 unknown coefficients in total to be identified. Employing the Particle Swarm Optimization method, the 16 coefficients are identified. The paper describes the detail coal mill model process, and simulation study has been conducted. The simulation results are presented. Although the work is still in its early stage, it has shown a potential to a fast algorithm for on-line updating mill coefficients. 20 refs., 6 figs., 1 tab.

J.L. Wei; P. Zachariades; J. Wang [University of Birmingham, Birmingham (United Kingdom). Department of Electronic, Electrical and Computer Engineering

2007-07-01

290

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)

291

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

292

Chirality Change by Grinding Crystals in Solution  

International Nuclear Information System (INIS)

One of the greatest unsolved problems in chemistry is the origin of homochirality in the biosphere, that is, the fact that l-amino acids and d-sugars dominate in biology, while laboratory experiments with stereoselective reactions only produce racemic mixtures. Several models have been proposed to address the question of how enantiomerically pure solutions or crystalline phases could have emerged from a presumably racemic prebiotic world. Here we show that two populations of amino acid crystals of 'left' and 'right' hand cannot coexist in solution: one of the chiral populations disappears in an irreversible autocatalytic process that nurtures the other one. Final and complete chiral purity seems to be an inexorable fate in our systems, under grinding, in the course of the common process of growth-dissolution. This unexpected chiral symmetry breaking has become firmly established but the underlying mechanism is being debated and we have no definitive answer.

293

The Grinding Wheel Performance in the Transverse Cylindrical Grinding of an Eutetic Alloy  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a research in which the performance of two different grinding wheels (a conventional and a CBN wheel was evaluated in a transverse cylindrical grinding of a eutectic alloy. Three cutting conditions were tested: rough, semi-finishing and finishing. As evaluating parameters, the cutting force, the roughness and the wheel wear were measured. As a result, the best values of the cutting force and the roughness were obtained when grinding with the conventional wheel, due to the best dressing operation performed, for all the cutting conditions. The CBN presented the best G ratio values. Although, the G ratio values observed for the CBN wheel were lower than the expected one due to the non-effective dressing operation applied. In the conditions tested, in terms of cutting force and roughness, the conventional wheel is the best choice. In terms of G ratio, a cost analysis is crucial to determine if the differences observed among the wheels can justify the use of the CBN wheel. In a positive case, the dressing operation must be improved.

Bianchi Eduardo Carlos

2002-01-01

294

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

295

Oil separation from foam fractions of enzymatically treated wet milled corn germ dispersions  

Science.gov (United States)

The many recent dry grind plants that convert corn to ethanol are potential sources of substantial amounts of corn oil, if an economical method of separating it can be developed. Oil was separated from corn germ by aqueous enzymatic extraction (AEE). Batches of wet- milled corn germ in water were...

296

Development of Roller Ends Forced-Contact Model and Cambering Technology for UCM Temper Mill (II——Development of cambering technology 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.

Zhenhua Bai

2011-07-01

297

Process monitoring in high efficiency deep grinding- HEDG  

International Nuclear Information System (INIS)

High Efficiency Deep Grinding (HEDG) is an emerging technology that allows grinding to be undertaken at high wheelspeeds (up to 250 m/s), relatively large depth of cut (1 to 25 mm or more) and extremely high workspeeds up to 1000 mm/s. However, this new technology is not fully understood, thus it needs further investigation into machining requirements in order to develop adequate strategies to control the process. Various sensors are used to monitor the process performance in grinding. Thermocouple technique is commonly used and has advantages of low-cost, ease of use and direct surface temperature measurement. Temperature measurement is particularly challenging in deep grinding with cuts that may exceed 5 mm and high workspeeds approaching 1 m/s. Grinding coolant and electrical noise cause further challenges for achieving accurate and reliable temperature measurement. A single-pole thermocouple technique that provides reliable measurements is presented. This paper presents various grinding force measurement techniques and the thermal modelling that has been used to predict temperature in the HEDG process as a function of cutting parameters. Results obtained for in-process monitoring of the high efficiency deep grinding using the power and temperature measurements are presents

298

Ultraprecision, high stiffness CNC grinding machines for ductile mode grinding of brittle materials  

Science.gov (United States)

Under certain controlled conditions it is now possible to machine brittle materials such as glasses and ceramics using single or multi-point diamond tools (grinding), so that material is removed by plastic flow, leaving crack-free surfaces. This process is called 'shear' or 'ductile' mode grinding. It represents a major breakthrough in modern manufacturing engineering since it promises to enable: - complex optical components, both transmission and reflecting to be generated by advanced CNC machines with very little (or even zero) subsequent polishing. - complex shaped components such as turbine blades, nozzle guide vanes, etc. to be finish machined after near net shape forming, to high precision in advanced ceramics such as silicon nitride, without inducing micro-cracking and thus lowering ultimate rupture strength and fatigue life. Ductile mode "damage free" grinding occurs when the volume of materials stressed by each grit of the grinding wheel is small enough to yield rather than exhibit brittle fracture, i.e. cracking. In practice, this means maintaining the undeformed chip thickness to below the ductile-brittle transition value; this varies from material to material but is generally in the order of 0.1 pm or 100 nm, (hence the term "nanogrinding" is sometimes used) . Thus the critical factors for operating successfully in the ductile regime are machine system accuracy and dynamic stiffness between each grit and the workpiece. In detail this means: (i) High precision 'truing' of the diamond grits, together with dressing of the wheel bond to ensure adequate ' openness'; (ii) Design and build of the grinding wheel spindle with very high dynamic stiffness; error motions, radial and axial, must be considerably less than 100 nfl. (iii) Design and build of the workpiece carriage motion system with very high dynamic stiffness; error motions, linear or rotary, must be well within 100 nm. (iv) Smooth, rumble-free, high-stiffness servo-drives controlling the motions which form the chip. In general, and as a rule of thumb, a machine "loop-stiffness" (between tool and workpiece) not less than 300 N,4im (static) is necessary.

McKeown, Patrick A.; Carlisle, Keith; Shore, Paul; Read, R. F.

1990-10-01

299

Parametric Roll Instability of Ships  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Parametric roll may be defined as the spontaneous rolling motion of the ship moving in head or following seas that comes about as a result of the dynamic instability of motion. The development of the parametric roll occurs under the conditions that the encounter angular frequency is approximately twice the roll angular frequency, the wavelength is equal to the ship length and the roll damping is insufficient to dissipate the parametric roll energy. In this Thesis t...

Sheikh, Irfan Ahmad

2008-01-01

300

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

 
 
 
 
301

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

International Nuclear Information System (INIS)

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

302

The thermal and metallurgical state of steel strip during hot rolling: Part I. Characterization of heat transfer  

Science.gov (United States)

A technique using intrinsic thermocouples was developed to monitor the thermal response of steel samples during hot rolling. A series of hot-rolling tests was conducted with the thermocoupleinstrumented samples on CANME’s pilot mill to simulate individual stands of Stelco’s Lake Erie Works hot-strip mill. A mathematical model of heat transfer in the roll bite has been employed to back calculate the roll/strip interface heat-transfer coefficients for lubricated and unlubricated conditions. The influence of reduction, rolling speed, and prerolling on roll-strip heat transfer has also been examined. For unlubricated rolling tests, the heat-transfer coefficient in the roll bite increased with time, reaching a steady-state value of 57 kW/m2 °C. The corresponding number for the lubricated tests was 31 kW/m2 °C. The observed variation in the interface heat-transfer coefficient with increasing strain and interface pressure points to a strong dependence on the real area of contact between the strip and rolls. Therefore, it appears that heat transfer between the two surfaces occurs primarily by conduction across asperity contacts. The high heat-transfer coefficients attained at the roll/strip interface promote chilling of the strip to a depth of approximately one-eighth of the thickness. To validate the overall heattransfer model, predicted surface temperatures of the strip have been compared with interstand temperature measurements obtained on the industrial mill using pyrometers.

Devadas, C.; Samarasekera, I. V.; Hawbolt, E. B.

1991-02-01

303

The effects of the fine grinding on the physicochemical properties and thermal behavior of bentonite clay  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, the results obtained by the mechanical treatment of bentonite clay Zavidinci, Serbia in a laboratory vibration mill with rings for different periods of time are presented. The successive structural changes of the minerals were studied by X-ray diffraction analysis, DTA analysis, IR spectroscopy and particle size distribution. The reactivity changes were controlled by CEC. The starting material and the material mechanically treated for 30 min were sintered at several temperature and for different time periods examined by X-ray diffraction. Mechanical treatment by fine grinding of bentonite clay produces structural changes of the powdered material and influences its behavior in further processing steps in particular after thermal treatment.

STANKA ERIC-ANTONI

2002-11-01

304

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

305

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

Directory of Open Access Journals (Sweden)

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

Nur Rafidah Yahaya

2012-01-01

306

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

307

A critical study of high efficiency deep grinding  

CERN Document Server

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

Johnstone, I

2002-01-01

308

Transformations during grinding of ceria-stabilized tetragonal zirconia polycrystals  

International Nuclear Information System (INIS)

This paper reports that Ce-TZP is reported to exhibit cyclic transformation during machine grinding. Previous conclusions were based on the results obtained by grinding Ce-TZP at a single speed and depth of cut. In the present work, grinding parameters were carefully chosen to induce varied stresses. Results show that Ce-TZP exhibits cyclic transformation, not always, but only under certain favorable grinding conditions. Results are supported by XRD, optical microscopy, and dynamometric observations. Three stages of transformation, namely, a mechanical-stress-induced t to m, a frictional-heat-driven m to t, and a thermal-quenching-stress-induced t to m, in sequence, are clearly identified

309

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)

310

Experimental investigation of abrasive electrodischarge grinding of Ti6Al4V titanium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: This work is focused on determination of effects of grinding conditions on effectiveness of abrasive electrodischarge grinding (AEDG) process applied for removal of machining allowance and forming of surface geometrical texture (SGT). These results were compared with one obtained for conventional grinding.Design/methodology/approach: The experimental investigations of deep-seated surface grinding of Ti6Al4V titanium alloy using CBN grinding wheel with metal bond were the ground for t...

S?wie?cik, R.

2009-01-01

311

Critical review of Nanofluid Minimum Quantity Lubrication for Grinding application  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

312

Prediction of residual stresses due to grinding with phase transformation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Shah, Syed Mushtaq Ahmed

2011-01-01

313

Methodology for automatic selection of passes in surface grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 for 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, th...

Dotto, Fa?bio R. L.; Paulo Roberto Aguiar; Rogério Thomazella; Eduardo Carlos Bianchi

2007-01-01

314

Applying laser irradiation and intelligent concepts to identify grinding phenomena  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Mohammed, Arif

2012-01-01

315

Dry-grinded ultrafine cements hydration. physicochemical and microstructural characterization  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 cements 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 finene...

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

2013-01-01

316

Performance analysis of magnesium phosphate cement mortar containing grinding dust  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Daniel Véras Ribeiro; Márcio Raymundo Morelli

2009-01-01

317

7.SP Rolling Dice  

Science.gov (United States)

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

318

Quantum dice rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A coin is just a two sided dice. Recently, Mochon proved that quantum weak coin flipping with an arbitrarily small bias is possible. However, the use of quantum resources to allow N remote distrustful parties to roll an N-sided dice has yet to be addressed. In this paper we show that contrary to the classical case, N-sided dice rolling with arbitrarily small bias is possible for any N. In addition, we present a six-round three-sided dice rolling protocol, achieving a bias of...

Aharon, N.; Silman, J.

2009-01-01

319

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

320

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.

 
 
 
 
321

A method to determinate the thickness control parameters in cold rolling process through predictive model via neural networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The single stand rolling mill governing equation is a non-linear function on several parameters (input thickness, front and back tensions, yield stress and friction coefficient among others). Any alteration in one of them will cause alterations on the rolling load and, consequently, on the outgoing thickness. This paper presents a method to determinate the appropriate adjustment for thickness control considering three possible control parameters: roll gap, front and back tensions. The method ...

Za?rate, L. E.

2005-01-01

322

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

323

29 CFR 1910.216 - Mills and calenders in the rubber and plastics industries.  

Science.gov (United States)

...or around to come in contact with the roll bite or...part of a mill, safety control devices listed in paragraph...or around to come in contact with the roll bite or...of a calender, safety control devices listed in paragraph...arrangement (individually or group-driven) shall...

2010-07-01

324

The effect of processing parameters on energy consumption of ball mill refiner for chocolate  

Directory of Open Access Journals (Sweden)

Full Text Available A laboratory ball mill consisting of vertical cylinder, equipped with a rotating shaft with arms, and filled with steel balls as a grinding medium has been used in the experiments. The aim of the study was to examine the effect of agitator shaft speed and amount of grinding media (steel balls on power requirements and energy consumption of a ball mill. With constant mass of the steel balls (20 kg, 30 kg and 40 kg, the agitator shaft speed was increased from 10% to 100% of the maximum speed which corresponds to a speed of 50 rpm. The power consumption (W was recorded upon which milling energy consumption (J/kg has been calculated. The results were statistically analyzed using ANOVA. The increase of the agitator shaft speed, in steps of 10% to the maximum speed of 50 rpm, led to a statistically significant increase in milling energy consumption. At low agitator shaft speed (10%, increase in the mass of the steel balls had no influence on the power requirements. Power requirements for the grinding runs using 30 kg and 40 kg are similar and higher compared to power requirement in trial with 20 kg, as agitator shaft speed increases from 20% to 70%. At high agitator shaft speeds (?80%, increase in steel balls mass led to the significant increase in power requirements of the ball mill.

Fišteš Aleksandar Z.

2013-01-01

325

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

Directory of Open Access Journals (Sweden)

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

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

Fernández Luco, L.

2003-12-01

326

Ship Roll Motion Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 performanc...

Perez, Tristan; Blanke, Mogens

2010-01-01

327

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

328

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

DEFF Research Database (Denmark)

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

Lagergren, J.; Wanheim, Tarras

2006-01-01

329

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 resea...

Zhenhua Bai; Hongxin Si; Xiaodong Shi; Linfang Han; Ruibing Long; Shoumin Wu; Xiujun Li; Dongdong Zhang

2011-01-01

330

Spray Rolling Aluminum Strip  

Energy Technology Data Exchange (ETDEWEB)

Spray forming is a competitive low-cost alternative to ingot metallurgy for manufacturing ferrous and non-ferrous alloy shapes. It produces materials with a reduced number of processing steps, while maintaining materials properties, with the possibility of near-net-shape manufacturing. However, there are several hurdles to large-scale commercial adoption of spray forming: 1) ensuring strip is consistently flat, 2) eliminating porosity, particularly at the deposit/substrate interface, and 3) improving material yield. Through this program, a new strip/sheet casting process, termed spray rolling, has been developed, which is an innovative manufacturing technique to produce aluminum net-shape products. Spray rolling combines the benefits of twin-roll casting and conventional spray forming, showing a promising potential to overcome the above hurdles associated with spray forming. Spray rolling requires less energy and generates less scrap than conventional processes and, consequently, enables the development of materials with lower environmental impacts in both processing and final products. Spray Rolling was developed as a collaborative project between the University of California-Davis, the Colorado School of Mines, the Idaho National Engineering and Environmental Laboratory, and an industry team. The following objectives of this project were achieved: (1) Demonstration of the feasibility of the spray rolling process at the bench-scale level and evaluation of the materials properties of spray rolled aluminum strip alloys; and (2) Demonstration of 2X scalability of the process and documentation of technical hurdles to further scale up and initiate technology transfer to industry for eventual commercialization of the process.

Lavernia, E.J.; Delplanque, J-P; McHugh, K.M.

2006-05-10

331

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)

332

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.

333

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

Directory of Open Access Journals (Sweden)

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

Wójcik R.

2014-10-01

334

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

International Nuclear Information System (INIS)

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

335

Fatigue Tests on Welded Joints Improved by Grinding  

DEFF Research Database (Denmark)

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

Agerskov, Henning; BjØrnbak-Hansen, JØrgen

2003-01-01

336

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

Directory of Open Access Journals (Sweden)

Full Text Available The contact between grinding wheel and workpiece in the grinding process is recognized by acoustic emission (AE. Two acoustic emission monitoring systems (MS were integrated into a 3 axis CNC grinding machine. A laptop allows the signal acquisition and visualization. The acquired AE RMS signals from 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

2012-03-01

337

Uranium milling operations at McClean Lake  

International Nuclear Information System (INIS)

The McClean Lake mill commenced operations in June 1999, with a design production capacity of 6 million pounds of U3O8 per year. The grinding circuit consists of a SAG mill and a ball mill in closed circuit with cyclones. The cyclone overflow is fed to a two-stage leaching circuit, which uses hydrogen peroxide as the oxidizing agent. A six-stage counter-current decantation circuit minimizes soluble losses to tailings. Solvent extraction uses tertiary amine as the extractant and ammonium sulphate as the stripping agent. The unit process consists of extraction, water wash, stripping and regeneration stages. Anhydrous ammonia is added to precipitate the uranium. The precipitate is then calcined to yield a high purity uranium oxide product. The process is described in detail, and operating data is presented. (author)

338

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

339

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

340

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.)

 
 
 
 
341

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

342

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

343

Offensive Rolling in Sambo  

Directory of Open Access Journals (Sweden)

Full Text Available In recent years the Soviet born martial art of sambo has become increasingly well known in martial art circles. This is largely due to the success of sambo fighters in various mixed martial art venues. Offered here is a brief description of sambo’s development as well as a delineation of one of sambo’s hallmark strategies: offensive rolling. Examples of proper forward rolling and three related offensive techniques are presented. This paper provides a brief introduction to sambo’s history and one of its key tactical philosophies.

Stephen Koepfer

2012-07-01

344

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

345

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

346

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

347

Determining the onset of grinding burn using Magnetic Barkhausen Noise  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A study of the quick non-destructive technique of Magnetic Barkhausen Noise (MBN) in detecting the onset of grinding burn in the absence of any microstructural changes during grinding has been undertaken. 51CrV4 Steel is a used in industry for manufacturing automotive parts (Nissan). Uniaxial tensile tests using a coarse surface whilst taking in situ MBN measurements were used to calibrate MBN to residual stress for hard and soft samples of 51CrV4. X-ray diffraction tests of...

Opoku, Kevin S.

2005-01-01

348

Possibilities of Pelletizing and Briquetting of Dusts from Castings Grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

349

Poplar stump grinding: analysis of work time and costs  

Directory of Open Access Journals (Sweden)

Full Text Available Poplar stump grinding: analysis of work time and costs. After harvesting and extracting poplar trees, the agricultural land should be restored for further cultivation by removing the root systems. This operation is done with extraction or stumps grinding using special machines. In Italy, the stumps grinding is actually the operation more practiced. This paper deals with an analysis of work time, productivity and costs of the poplar stumps grinding, performed by two different operators. The poplar plantation was established with Neva (Populus x euramericana clone and was harvested in march 2012. The plantation was located in Monterotondo (Rome, inside the farm of the Agricultural Engineering Research Unit (CRA-ING. Inside of two experimental plots, of the unit surface area of 0.66 ha, the diameters of all the stumps (220 has been measured in order to establish a correlation between the gross grinding time and the diameter of the grinded stump. The influence of diameter of stump on the grinding cycle time was assessed by a regression of the type T = A + Bx, where T is the gross time of grinding, A and B coefficients to be determined and x is the diameter of the stump. The resulted regressions were subjected to ANOVA test. The results showed an average work productivity of 111 stumps h-1, with significant differences between operators that underlines the importance of experience and competence of the operator. The productivity obtained on stumps with small diameters (23 cm can reach 157 stumps h-1 for the expert operator, against 106 stumps h-1 of a less expert operator. The economic analysis was assessed on a cost per stump and per hectare. In referring to the average of the stumps diameters in the experimental plots (30 cm, an average cost of 1.57 € stump-1 was calculated, corresponding to 522 € ha-1, with a lower cost for expert operator corresponding to 424 € ha-1 (1.27 € stump-1, and a higher cost for the other operator of € 620 ha-1 (1.86 € stump-1.

Sperandio G

2012-12-01

350

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

351

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.)

352

Graphic presentation of information of acoustic monitoring of stream grinding process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The theoretical and experimental mechanisms of thin grinding the loose materials are analyzed. The relation of the density function of acoustic signal amplitudes of grinding process to the degree of loading the jets by material is established.

Pryadko, N. S.; Bulanaya, T. M.; Shegeda, K. V.

2012-01-01

353

Graphic presentation of information of acoustic monitoring of stream grinding process  

Directory of Open Access Journals (Sweden)

Full Text Available The theoretical and experimental mechanisms of thin grinding the loose materials are analyzed. The relation of the density function of acoustic signal amplitudes of grinding process to the degree of loading the jets by material is established.

N.S. Pryadko

2012-04-01

354

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

355

Exact Solution for the Time-Dependent Temperature Field in Dry Grinding: Application to Segmental Wheels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a closed analytical solution for the time evolution of the temperature field in dry grinding for any time-dependent friction profile between the grinding wheel and the workpiece. We base our solution in the framework of the Samara-Valencia model Skuratov et al., 2007, solving the integral equation posed for the case of dry grinding. We apply our solution to segmental wheels that produce an intermittent friction over the workpiece surface. For the same grinding parameters, we plot t...

Isidro, J. M.; Placeres, J. M. Vald Amp S.; Gonz Amp Lez-santander, J. L.

2011-01-01

356

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work aims to develop an intelligent system for detecting the workpiece burn in the surface grinding process by utilizing a multi-perceptron neural network trained to generalize the process and, in turn, obtnaing the burning threshold. In general, the burning occurrence in grinding process can be detected by the DPO and FKS parameters. However, these ones were not efficient at the grinding conditions used in this work. Acoustic emission and electric power of the grinding wheel drive motor...

Fábio Romano Lofrano Dotto; Paulo Roberto Aguiar; Eduardo Carlos Bianchi; Rogério Andrade Flauzino; Gustavo de Oliveira Castelhano; Landry Pansanato

2003-01-01

357

A study of the convection heat transfer coefficients of grinding fluids  

Digital Repository Infrastructure Vision for European Research (DRIVER)

By using hydrodynamic and thermal modelling, the variation of the convection heat transfer coefficient (CHTC) of the process fluids within the grinding zone has been investigated. Experimental measurements of CHTC for different grinding fluids have been undertaken and show that the CHTC depends on the grinding wheel speed and the fluid film thickness within the contact zone. The film thickness is determined by grinding wheel speed, porosity, grain size, fluid type, flow rate...

Jin, T.; Stephenson, David J.

2008-01-01

358

Hot strip mill as an experimental tool (review)  

Energy Technology Data Exchange (ETDEWEB)

The occurrence of carbonitride precipitation during the short interpass times associated with hot strip rolling is considered, together with the interaction between precipitation and static recrystallization under these conditions. The characteristics of work hardening and of strain accumulation at the high temperatures (850 to 1,050 degree C) involved in strip rolling are described. Expressions are introduced that specify the kinetics of softening (by static or metadynamic recrystallization) during the interpass interval in various grades of steel. Using these kinetics in an appropriate mill model, the mean flow stresses pertaining to various mill stands are predicted. These values are compared with the measured ones derived directly from mill logs. It is shown how discrepancies between the predicted and measured values can be used to improve the accuracy of the expressions for the kinetics. This is one way in which a hot strip mitt can be used as an 'experimental tool'. (author)

Jonas, J.J.

2000-08-01

359

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

360

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

 
 
 
 
361

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

362

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

363

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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; José Adilson de, Castro; Luciano Pessanha, Moreira; Elder Moreira, Hemerly.

2012-12-01

364

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

365

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

366

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

367

Global analysis of aerodynamics deflectors efficiency in the grinding process  

Scientific Electronic Library Online (English)

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

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

2006-06-01

368

Microstructure Evolution During Spray Rolling and Heat Treatment of 2124 Al  

Energy Technology Data Exchange (ETDEWEB)

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 move an alloy’s latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly-solidified product. While similar in many ways to twin-roll casting, spray rolling is able to process a broader range of alloys and operates at a higher production rate. A laboratory-scale strip caster has been constructed at INL and used to evaluate the interplay of processing parameters and strip quality while producing strips up to 200 mm wide and 1.6 – 6.4 mm thick. Plans are underway to scale to 600 mm width and demonstrate steady-state operation. As-spray-rolled strip is characterized by a flat, uniformly thick profile with minimal porosity or segregation. This paper examines how processing parameters influence the microstructure transformations that take place during spray rolling and post-deposition heat treatment of 2124 Al.

K.M. McHugh; Y. Lin; Y. Zhou; S.B. Johnson; J.P. Delplanque; E.J. Lavernia

2006-09-01

369

Hydrogenation of nanostructured graphite by mechanical grinding under hydrogen atmosphere  

International Nuclear Information System (INIS)

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

370

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

371

Effects of grinding on properties of Mg-PSZ ceramics prepared by the surface enrichment of zirconia powders  

International Nuclear Information System (INIS)

Commercial grade zirconia powders of mean particle size of 3.21 microns were super-ground in wet condition in alcoholic medium in a Planetary Ball-Mill for 12-hours using a zirconia pot as well as balls, in order to avoid contaminations from the grinding media. Sedigraph analysis data show the mean particle sizes within the range of 0.4 to 0.2 micron. The super-ground zirconia powders were then treated with appropriate acid and alkali solutions in order to enrich the surfaces of zirconia powders. The chemical analysis reports depict the enrichment phenomena of the processed zirconia powders. Magnesium oxide of different mole percentages (3 to 9%) have been incorporated to the above super-ground and enriched zirconia powder and green specimens were prepared by pressing with a suitable pressure of 200 MPa to yield the green compaction density of 3.06 gm/cm3. The compacted green specimens were sintered without pressure at 1,480 C in air followed by normal cooling. X-ray diffraction patterns of the above sintered and cooled specimens have confirmed the formation of Mg-PSZ ceramics with 40% tetragonal phase. The sintered PSZ-products have shown very good surface properties but at the cost of transverse rupture strength. The effects of grinding were observed on the above Mg-PSZ ceramics which exhibit very little change in the tetragonal phase even after 30-minutes of grinding with a 60-mesh diamond wheel at a normal pressure of 4 kg/cm2ure of 4 kg/cm2

372

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

373

Modernitetens Rolle Under Holocaust  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Projektet søger, ved hjælp af Zygmunt Baumans modernitetsteori, at afklare hvilken rolle moderniteten spillede i tilblivelsen af Holocaust. Propagandaen var en markant del af det nazistiske bureaukratiske styre, men da Bauman ikke udførligt diskuterer dette, er det et emne, vi ønsker at belyse nærmere. Dette gøres ved at analysere de to nazistiske propagandafilm, Der Ewige Jude og Jud Süss. Moderniteten indeholder faktorer, som kan være behjælpelige til en forståelse af,...

Jespersen, Simon M.

2012-01-01

374

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

International Nuclear Information System (INIS)

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

375

Experimental investigation of abrasive electrodischarge grinding of Ti6Al4V titanium alloy  

Directory of Open Access Journals (Sweden)

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

R. ?wi?cik

2009-12-01

376

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

Science.gov (United States)

Abstract 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

2014-11-01

377

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

378

Speed roll laws influence in a Ring Rolling process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

379

Development of recycling technique of mill reject products using triboelectrostatic separation  

Energy Technology Data Exchange (ETDEWEB)

This study was to develop the triboelectrostatic separation technique to recycle the coal from about 20% of mill reject products remained by grinding process in the coal thermoelectric power plant. In this study, we get a test results that can product the cleaned coal of 15% ash content and 66.23% recovery from mill reject of 47% ash content. And then, from the result of the releases analysis, we proved the excellence of treatment method, after showing the treatment processing which is able to get 80% of recovery of coal from 20% of ash content demanded in the power plant. (author). 8 refs., 2 tabs., 11 figs.

Jeon, Ho-Seok; Shin, Shun-Myung [Korea Institute of Geoscience and Mineral Resources, Taejeon(Korea); Han, Oh-Hyung [Chosun University, Kwangju(Korea); Yoon, Roe-Hoan [Virginia Polytechnic Institute and State University, Blacksburg, VA(United States)

2002-04-30

380

Spirit's First Grinding of a Rock on Mars  

Science.gov (United States)

The round, shallow depression in this image resulted from history's first grinding of a rock on Mars. The rock abrasion tool on NASA's Spirit rover ground off the surface of a patch 45.5 millimeters (1.8 inches) in diameter on a rock called Adirondack. The hole is 2.65 millimeters (0.1 inch) deep, exposing fresh interior material of the rock for close inspection with the rover's microscopic imager and two spectrometers on the robotic arm. This image was taken by Spirit's panoramic camera, providing a quick visual check of the success of the grinding. The rock abrasion tools on both Mars Exploration Rovers were supplied by Honeybee Robotics, New York, N.Y.

2004-01-01

 
 
 
 
381

Grinding Machine Noise Spectra in Kaduna Metropolis, Nigeria  

Directory of Open Access Journals (Sweden)

Full Text Available When we are exposed to intense noise levels some or all of the hair cells in the organ of corti may be damaged temporarily or permanently. Exposure to excessive noise for a short period of time may produce a loss of heavy sensitivity. Continuous noise exposure over a long period of time (years is more damaging than interrupted exposure to noise, which permits the ear to have a rest and possible recovery period. The presence of low frequency noise in the noise generated by grinding machines in Kaduna metropolis can have adverse effect on concentration and memory.Thus, this study was carried out to assess the grinding machine noice spectra in Kaduna Metropolis using sound level meter (Digital, Testo 816 and Digital Hand Data Logger (DB-525.

Ali Haruna

2011-04-01

382

Performance analysis of magnesium phosphate cement mortar containing grinding dust  

Scientific Electronic Library Online (English)

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

Daniel Véras, Ribeiro; Márcio Raymundo, Morelli.

2009-03-01

383

DEFECTS SIMULATION OF ROLLING STRIP  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The defects in the continuous casting slabs can be developed or kept down in principle by rolling technology, especially depend to sort, size and distribution of primary defects, as well as used of rolling parameters. Scope of the article is on observation behavior artificial surface and undersurface defects (scores) without filler (surface defects) and filling by oxides and casting powder (subsurface defects). First phase of hot rolling process have been done by software simulation DEFORM 3D...

Rudolf Miši?ko; Tibor Kva?kaj; Martin Vlado; Lucia Gulová; Miloslav Lupták; Jana Bidulská

2009-01-01

384

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

385

Investigation of glycerol polymerization in the clinker grinding process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Concrete production is a large scale process that involves high energy consumption. In order to increase the sustainability of this process, the reduction of energy input is necessary. Bio-glycerol was demonstrated to be a highly efficient renewable-based additive in the grinding process for concrete production and helped reduce energy costs and improve the quality of the resulting product. In order to understand its excellent aiding properties, the interaction of glycerol with cement clinker...

Parvulescu, A. N.; Rossi, M.; Della Pina, C.; Ciriminna, R.; Pagliaro, M.

2011-01-01

386

Study of thresholds to burning in surface grinding process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2005-01-01

387

Adaptive control of the grinding of large gas turbine blades  

Energy Technology Data Exchange (ETDEWEB)

A fully automated process for the dimensional grinding of large gas turbine blades has been developed, with the shaping of the blades controlled adaptively based on deformations in excess of the allowance and based on allowance fluctuations. Formulas are presented for determining and predicting deformations from the cutting forces. A model is developed and used in a series of simulations aimed at the evaluation and optimization of different system operation modes.

Moiseeva, L.T.; Iunusov, F.S.; Lunev, A.N.

1988-01-01

388

Production of Near-Mirror Surface Quality by Precision Grinding  

Science.gov (United States)

Mechanical components such as gears and bearings operate with the working surfaces in intimate contact with a mating part. The performance of such components will be influenced by the quality of the working surface. In general, a smoother surface will perform better than a rougher surface since the lubrication conditions are improved. For example, surfaces with a special near-mirror quality finish of low roughness performed better than ground surfaces when tested using a block-on-ring arrangement. Bearings with near-mirror quality have been tested and analyzed; lower running torques were measured and improved fatigue life was anticipated. Experiments have been done to evaluate the performance of gears with improved, low roughness surface finishing. The measured performance improvements include an increased scuffing (scoring) load capacity by a factor of 1.6, a 30-percent reduction of gear tooth running friction, and longer fatigue lives by a factor of about four. One can also anticipate that near-mirror quality surface finishing could improve the performance of other mechanical components such as mechanical seals and heavily loaded journal bearings. Given these demonstrated benefits, capable and economical methods for the production of mechanical components with near-mirror quality surfaces are desired. One could propose the production of near-mirror quality surfaces by several methods such as abrasive polishing, chemical assisted polishing, or grinding. Production of the surfaces by grinding offers the possibility to control the macro-geometry (form), waviness, and surface texture with one process. The present study was carried out to investigate the possibility of producing near-mirror quality surfaces by grinding. The present study makes use of a specially designed grinding machine spindle to improve the surface quality relative to the quality produced when using a spindle of conventional design.

Dimofte, Florin; Krantz, Timothy

2003-01-01

389

Coiling Temperature Control in Hot Strip Mill  

Science.gov (United States)

Coiling temperature is one of the most significant factors in products of hot strip mill to determine material properties such as strength, toughness of steel, so it is very important to achieve accurate coiling temperature control (CTC). Usually there are a few pyrometers on the run out table in hot strip mill, therefore temperature model and its adapting system have large influences on the accuracy of CTC. Also unscheduled change of rolling speed has a bad effect to keep coiling temperature as its target. Newly developed CTC system is able to get very accurate coiling temperature against uncertain factors and disturbances by adopting easily identified temperature model, learning method and dynamic set up function. The features of the CTC system are discussed with actual data, and the effectiveness of the system is shown by actual control results.

Imanari, Hiroyuki; Fujiyama, Hiroaki

390

Twin roll casting of magnesium alloys with high aluminum contents  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The purpose of the work is to establish a manufacturing process and technology to facilitate theeconomical manufacture of high-quality magnesium sheet alloys with high aluminum contents, such as AZ61and AZ91. The aim of the work is to establish a twin roll casting technology to facilitate the manufacture ofAZ61 and AZ91 magnesium sheet alloys economically whilst maintaining high quality.Design/methodology/approach: A horizontal type twin roll caster was used to manufacture thin magnesium alloysheets of AZ61 and AZ91. Pair of copper alloy roll and pure copper roll was used for the horizontal type twin roll caster.A closed type tundish was set to the roll caster to keep stable contact of molten magnesium with upper and lower rolls.Findings: The experiment results clarified that AZ61 and AZ91 sheets can be manufactured by twin roll castingprocess. The product sheet thickness in the present experiment is 2.0 to 4.5 mm for AZ91, 2.5 to 5.0mm forAZ61. Mill stiffness and a method of predicting the cast sheet’s thickness were investigated to determine theappropriate manufacturing conditions. The microstructure of AZ61 cast strips was equiaxed structure and thecrystal sizes are different depending on cross section observed. The dendric and equiaxed microstructure wereseen in the microstructure of AZ91 cross section. The intermetllic Mg17Al12 was seen in the grain boundary inAZ91 when roll speed was very slow. The grain size of the manufactured wrought magnesium alloys sheet wasless than 10 micrometers. The obtained magnesium alloy sheet exhibited an equivalent limiting drawing ratio ina warm-drawing test. The limiting drawing ratio of AZ61 was 2.6 and 2.4 for AZ91.Research limitations/implications: The suitable roll speed was from 9m/min to 15m/min in manufacturingAZ91 and AZ61 strip using copper alloy rolls. When in use of pure copper roll, strips were cast between 6m/minand 20m/min for manufacturing AZ61 and AZ91. The superheats in the experiment were 15ºC and 30ºC. Thecast strips should be hot rolled at 300ºC.Originality/value: value In this experiment, it is clarified that AZ61, AZ91 sheets can be manufactured by twinroll casting. These cast sheet can be hot rolled and the manufacturing process by twin roll casting enable tomanufacure thin magnesium sheet alloys with high aluminum contents. It has been found that the manufacturedcast AZ61 and AZ91 have good formability by a warm deep drawing test.

H. Watari

2006-08-01

391

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...

392

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

393

STS-49 Roll Out  

Science.gov (United States)

One step closer to its maiden voyage, the Space Shuttle Orbiter Endeavour rolls out of the Vehicle Assembly Building, headed to Launch Pad 39B. Launched on May 7th 1992, the STS-49 mission was the first U.S. orbital flight to feature 4 extravehicular activities (EVAs), and the first flight to involve 3 crew members working simultaneously outside of the spacecraft. The primary objective was the capture and redeployment of the INTELSAT VI (F-3) which was stranded in an unusable orbit since its launch aboard the Titan rocket in March 1990.

1992-01-01

394

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

395

In-process grinding monitoring through acoustic emission  

Scientific Electronic Library Online (English)

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

396

Possibilities of Pelletizing and Briquetting of Dusts from Castings Grinding  

Directory of Open Access Journals (Sweden)

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

A. Pribulová

2010-04-01

397

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

398

The influence of the shape of grooves on the behavior of internal material discontinuities in continuous S355J2G3 steel strands during rolling  

Directory of Open Access Journals (Sweden)

Full Text Available The article discusses problems related to the influence of rolling processes on the process of closing of internal discontinuities in continuous castings during rolling in shape grooves. Numerical modelling of the process of rolling 160 × 160 mm continuous S355J2G3 steel strands was carried out using the Forge 2008R software program. The experimental studies were conducted in a D150 laboratory rolling mill. Holes simulating material discontinuities were examined. In numerical and experimental studies, in steel samples after rolling in the third rolling stand, the defects were closing in 100 % on average. It was stated that the speed of closing of material discontinuities in feedstock is strongly influenced by the shape of the rolling groove.

H. Dyja

2014-10-01

399

Textures of molybdenum monocrystal deformation in rolling in profiled rolls  

International Nuclear Information System (INIS)

The texture of molybdenum monocrystals rolled in profiled rolls with epsilon=6-90% cogging is studied by the method of reverse pole figures in Mo Ksub(?) radiation. The crystallographic directions of and were oriented in the deformation direction. At different orientation of the monocrystal in the rolling plane after epsilon=25-27% in the rolling direction (RD) different crystallographic orientations were formed which is caused by pointing accuracy of the monocrystal in the deformation plane. Rolling of a monocrystal with long RD orientation provokes RD reorientation and formation of the (111) [011] texture at high deformation degree. At average cogging degrees (epsilon=35-60%) the total axial texture long RD is formed transforming into a limited axial one and then into an axial one with the deformation degree increase

400

Surface integrity on grinding of gamma titanium aluminide intermetallic compounds  

Science.gov (United States)

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

Murtagian, Gregorio Roberto

 
 
 
 
401

Milling of agglomerates in an impact mill.  

Science.gov (United States)

Milling of agglomerates is one of the common unit operations during preparation of oral dosage forms like capsules and tablets. In literature the breakage of granules is mostly determined after single impact at an ideally formed granule or of single particles. In this paper the breakage behavior of agglomerates after milling with multiple impacts has been studied. It investigates the effects of the formulation and the influences of the mill settings. With respect to the formulation it has been found that both the size of the particles before granulation and the amount of binder used determine the breakage behavior. Both parameters have an influence on the strength of the granule to be milled, where initial particle size has the largest effect. A relation has been found between the strength of granules and the degree of size reduction. Regarding the mill settings, there are no mill parameters which influence the formation of fines independently. Formation of fines is always the result of the total degree of size reduction. It is not possible to achieve a large degree of size reduction without intensive fines formation. The results indicate that it is possible to achieve every desired average particle size. However, when formation of dust has to be reduced, multiple milling steps with separation of in-size particles is necessary. PMID:15158958

Verheezen, Joost J A M; van der Voort Maarschalk, Kees; Faassen, Fried; Vromans, Herman

2004-06-18

402

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.

403

Advanced Modeling and Materials in Kraft Pulp Mills  

Energy Technology Data Exchange (ETDEWEB)

This CRADA provided technical support to the Weyerhaeuser Company on a number of issues related to the performance and/or selection of materials at a number of locations in a pulp and paper mill. The studies related primarily to components for black liquor recovery boilers, but some effort was directed toward black liquor gasifiers and rolls for paper machines. The purpose of this CRADA was to assist Weyerhaeuser in the evaluation of materials exposed in various paper mill environments and to provide direction in the selection of alternate materials, when appropriate.

Keiser, J.R.; Gorog, J.P.

2002-05-15

404

Influence of cryogenic cooling on surface grinding of stainless steel 316  

Science.gov (United States)

The objective of the present investigation is to evaluate the improvements in the grinding force and surface roughness by the application of LN2 (liquid nitrogen) as a coolant in the cryogenic grinding process. Cryogenic machining is an environment concerned green manufacturing process. The grinding experiments were conducted on stainless steel 316 in three environments, namely, dry, wet and cryogenic cooling. The experimental results show that a reduction in the grinding zone temperature leads to excellent benefits in the machining performance. The cryogenic coolant offers 37% and 13% reduction in the grinding forces compared to dry and wet cooling. The surface roughness under cryogenic cooling is found to produce 59% and 32% lesser values and fewer defects, compared to surfaces ground with dry and wet cooling. The enhancements realized by the delivery pressure of the cryogen, with respect to the grinding forces, and surface roughness were also studied.

Manimaran, G.; Pradeep kumar, M.; Venkatasamy, R.

2014-01-01

405

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

406

Rolling friction of adhesive microspheres  

Science.gov (United States)

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

Krijt, S.; Dominik, C.; Tielens, A. G. G. M.

2014-04-01

407

Slipping and Rolling Wheel Model  

Science.gov (United States)

The EJS Slipping and Rolling Wheel Model shows the motion of a wheel rolling on a floor subject to friction. The simulation allows the user to change the initial translational and rotational velocities of the wheel, v and ?, the mass, radius, and mass distribution, R, m, and C of the wheel. By controlling these variables, the dynamics of the wheel can be changed to show the sliding, then rolling without slipping, of the wheel. The Slipping and Rolling Wheel Model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_mech_newton_SlippingRollingWheel.jar file will run the program if Java is installed. The user can modify this simulation if EJS is installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item.

Christian, Wolfgang; Belloni, Mario

2009-02-26

408

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

409

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a review of researches on CBN (cubic boron nitride) grinding wheels with the purpose of identifying the state of art in abrasive machining and serving as the basis for future researches and laboratory tests. The scientific studies investigated here report on interesting results involving grinding, published by Brazilian and foreign authors. The methods and the results are presented and discussed. In addition, a grinding setup is presented which provides more reliable exper...

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

2003-01-01

410

Cylindrical grinding of SiC particles reinforced aluminium metal matrix composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

411

Thermal Model to Investigate the Temperature in Bone Grinding for Skull Base Neurosurgery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study develops a thermal model utilizing the inverse heat transfer method (IHTM) to investigate the bone grinding temperature created by a spherical diamond tool used for skull base neurosurgery. Bone grinding is a critical procedure in the expanded endonasal approach to remove the cranial bone and access to the skull base tumor via nasal corridor. The heat is generated during grinding and could damage the nerve or coagulate the blood in the carotid artery adjacent to the bone. The finit...

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

2013-01-01

412

Surface quality of a 1m Zerodur part using an effective grinding mode  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new ultra precision large optics grinding machine, BoX(R), has been developed at Cranfield University. This machine is located at the UK's Ultra Precision Surfaces laboratory at the OpTIC Technium, North Wales. This machine offers a rapid and economic solution for grinding large off-axis aspherical and free-form optical components. This paper presents an analysis of surface and subsurface damage assessments of Zerodur(R) ground using diamond resin bonded grinding wheels. Z...

Tonnellier, Xavier; Shore, Paul; Morantz, Paul; Orton, D.

2012-01-01

413

Investigation of the Formation Process of Two Piracetam Cocrystals during Grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 p...

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

2011-01-01

414

Investigation of the Formation Process of Two Piracetam Cocrystals during Grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

415

Virtual Sensors for On-line Wheel Wear and Part Roughness Measurement in the Grinding Process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Grinding is an advanced machining process for the manufacturing of valuable complex and accurate parts for high added value sectors such as aerospace, wind generation, etc. Due to the extremely severe conditions inside grinding machines, critical process variables such as part surface finish or grinding wheel wear cannot be easily and cheaply measured on-line. In this paper a virtual sensor for on-line monitoring of those variables is presented. The sensor is based on the modelling ability of...

Ander Arriandiaga; Eva Portillo; Sa?nchez, Jose A.; Itziar Cabanes; Iñigo Pombo

2014-01-01

416

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Yuji Yamamoto, Hirofumi Suzuki

2007-01-01

417

Phase transformation of single crystal silicon induced by grinding with ultrafine diamond grits  

International Nuclear Information System (INIS)

Phase transformation of single crystal silicon (Si) was investigated under various grinding conditions using high-resolution transmission electron microscopy. Nanocrystals with sizes ranging from 6 to 20 nm of diamond cubic silicon (Si-I) and high-pressure phase (Si-III) were observed in the grinding-induced amorphous Si layers. The phase transformation pattern was found to be influenced by the thermal status involved in the grinding processes.

418

Relations between subsurface damage depth and surface roughness of grinded fused silica.  

Science.gov (United States)

Relationships between subsurface damage (SSD) depth and peak to valley surface roughness (Rt) have been widely studied and present a major interest for an easy assessment of the SSD depth. We look at the relation between SSD depth and other surface roughness parameters using the Abbott-Firestone curve on a large campaign of grinding tests (with different abrasive grain size, grinding speed and grinding mode). The results reveal that Abbott-Firestone parameters are better for an assessment of SSD depth and that relationships between SSD depth and surface roughness are not universal but depend on the grinding process. PMID:24514620

Blaineau, P; Laheurte, R; Darnis, P; Darbois, N; Cahuc, O; Neauport, J

2013-12-16

419

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

420

Research on Static and Dynamic Performance of Spindle System of the Grinding Head  

Directory of Open Access Journals (Sweden)

Full Text Available The article studied the vibration resistance of spindle system in grinding head of roller grinding machine by means of harmonic response and modal analysis, the system modal analysis use the method of the transfer matrix, obtained the first five orders of the natural frequency of spindle system, calculated the natural frequency of spindle system by the displacement-frequency curve of the spindle system harmonic response. By studying the M84100A type spindle system in grinding head of roller grinding machine, obtained the conclusion that the natural frequency was far from the work frequency, so laid a foundation of the spindle system dynamic design.

Jin-Ling Cao

2013-01-01

 
 
 
 
421

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)

422

Rolling Stone Radio  

Science.gov (United States)

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

423

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

424

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

425

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

426

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

427

Mathematical models of homochiralisation by grinding of crystals  

CERN Document Server

We review the existing mathematical models which describe physicochemical mechanisms capable of producing a symmetry-breaking transition to a state in which one chirality dominates the other. A new model is proposed, with the aim of elucidating the fundamental processes at work in the crystal grinding systems of Viedma [Phys Rev Lett 94, 065504, (2005)] and Noorduin [J Am Chem Soc 130, 1158, (2008)]. We simplify the model as far as possible to uncover the fundamental competitive process which causes the symmetry-breaking, and analyse other simplifications which might be expected to show symmetry-breaking.

Wattis, Jonathan AD

2010-01-01

428

Grinding Machine Noise Spectra in Kaduna Metropolis, Nigeria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

When we are exposed to intense noise levels some or all of the hair cells in the organ of corti may be damaged temporarily or permanently. Exposure to excessive noise for a short period of time may produce a loss of heavy sensitivity. Continuous noise exposure over a long period of time (years) is more damaging than interrupted exposure to noise, which permits the ear to have a rest and possible recovery period. The presence of low frequency noise in the noise generated by grinding machines i...

Ali Haruna; Agu, M. N.

2011-01-01

429

FM Interviews: Stephanie Mills  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

430

Roll Control in Fruit Flies  

CERN Document Server

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

Beatus, Tsevi; Cohen, Itai

2014-01-01

431

Nonlinear Observers for Parametric Roll  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

432

Numerical simulation of shape rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Riljak, Stanislav

2006-01-01

433

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

434

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

435

Use of a fluidized bed hammer mill for size reduction and classification: effects of process variables and starting materials on the particle size distribution of milled lactose batches.  

Science.gov (United States)

The process capability of a fluidized bed hammer mill was investigated with respect to four process variables, namely, rotational speeds of beater system and classifier wheel, airflow rates and length of grinding zones, as well as the particle size and flow property of the starting materials. The size distributions of all the milled lactose batches could be fitted to the Rosin Rammler distribution (RRD) function. The characteristic particle size (De) and uniform coefficient (n), which were derived from the RRD function, complemented the size at the 99th percentile of the cumulative undersize distribution (D99) to characterize the lactose batches. Lower De and D99 values indicate a finer powder while a higher n value indicates a narrower size distribution. The beater speed played a critical role. Increasing the beater speed from 12000 to 21000 rpm generally resulted in an increase in n and a decrease in D99 values due to the greater amount of milling energy supplied. The particle size and flow property of the starting material also played an important role at beater speed of 12000 rpm, where the lowest amount of milling energy was supplied. When a higher amount of milling energy was provided, the effect of particle size of the starting material was less significant. The other process variables exerted varying effects. Increasing the classifier wheel speed from 5000 to 15000 rpm decreased the De and D99 and increased the n values of the milled lactose batches, provided sufficient milling energy was supplied to the lactose particles. Changing airflow rates from 80 to 90 m3/h generally resulted in larger De and D99 values and lower n values as the higher airflow rate provided greater airflow-induced kinetic energy that facilitated the passage of lactose through the classifier wheel. However, changing the long grinding zone to a short one did not significantly affect the De, D99 and n values of the milled lactose batches produced. Small lactose particles of narrow size distribution could be obtained using the fluidized bed hammer mill upon gaining a better understanding of the milling process. PMID:14601967

Lee, C C; Chan, L W; Heng, Paul W S

2003-01-01

436

Sharpening ball-nose mill cutters  

Science.gov (United States)

Economical attachment allows faster, more precise grinding. Vibrationless and rigid relation between grinding wheel and cutter allows for extremely high finish and accurate grinding. Leveling device levels flutes with respect to toolholder rotation that generates ball-nose radius. Constant relief around entire profile of cutting edge produces longer tool life.

Burch, C. F.

1977-01-01

437

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

438

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

439

Body roll in swimming: a review.  

Science.gov (United States)

In this article, we present a critical review of the swimming literature on body roll, for the purposes of summarizing and highlighting existing knowledge, identifying the gaps and limitations, and stimulating further research. The main research findings can be summarized as follows: swimmers roll their shoulders significantly more than their hips; swimmers increase hip roll but maintain shoulder roll when fatigued; faster swimmers roll their shoulders less than slower swimmers during a 200-m swim; roll asymmetries, temporal differences in shoulder roll and hip roll, and shoulder roll side dominance exist in front crawl swimming, but there is no evidence to suggest that they affect swimming performance; and buoyancy contributes strongly to generating body roll in front crawl swimming. Based on and stimulated by current knowledge, future research should focus on the following areas: calculation of body roll for female swimmers and for backstroke swimming; differences in body roll between breathing and non-breathing cycles; causes of body roll asymmetries and their relation to motor laterality; body roll analysis across a wide range of velocities and swimming distances; exploration of the association between body roll and the magnitude and direction of propulsive/resistive forces developed during the stroke cycle; and the influence of kicking actions on the generation of body roll. PMID:20131140

Psycharakis, Stelios G; Sanders, Ross H

2010-02-01

440

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

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