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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

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

Energy Technology Data Exchange (ETDEWEB)

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

Fuerstenau, D.W.; De, A.

1996-08-01

3

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

4

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

5

Contamination of rock samples by laboratory grinding mills  

International Nuclear Information System (INIS)

Contamination of samples of granite, quartz porphyry, greenstone and dolerite after grinding them in steel and cemented carbide grinding mills was measured. The steel mill contaminated the granite with Fe. The cemented carbide mill contaminated all samples with W and Co, and the granite and quartz porphyry with Ta. Contamination during grinding is proportional to the free quartz content of the rock and to the grinding time. (author)

2000-06-01

6

Wet Autogenous Grinding in Tumbling Mills.  

Science.gov (United States)

After a general introduction the article discusses at length the various grinding mechanisms operative in autogenous grinding. The viewpoints developed are then used for a review of the operational aspects, especially concerning process limitations, regul...

M. Digre

1969-01-01

7

Wet grinding in ball mills. Pt. 1. Power consumption and movement of grinding elements  

Energy Technology Data Exchange (ETDEWEB)

Using a direct comparison of wet and dry grinding, the effect of liquid on power consumption and movement of grinding element in a wet-operated ball mill is investigated, where the most important parameters such as RPM of mill, ball density, quantity of material being ground, quantity of liquid and the number of lift bars are largely varied systematically. The comparison of wet and dry grinding is made on the basis of two dimensionless factors, the solids volume proportion c/sub V/ and the new defined degree of pulp filling f/sub T/, which is described in detail.

Leluschko, J.; Kirchner, K.

1988-10-01

8

Control for Cold Rolling Mills  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This report contains the details in a final research thesis work done rolling mill technology. The work is carried out at Heat Transfer located at Finspång. The main objective of this work is to evaluate thickness and flatness data from the profile to give an optimal start value for the pressure and force applied on the machine and the speed as well, so that the profiles produced, have the right thickness and best possible flatness. Thickness, start value for power, the degree of bending the...

Morad, Antoni; Travancic, Faruk

2005-01-01

9

Evaluation of Recycle Grinding Performance in Flour Milling  

Directory of Open Access Journals (Sweden)

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

Siti Mazlina Mustapa Kamal

2007-01-01

10

[Dehulling of sorghum in grinding mills].  

Science.gov (United States)

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

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

1986-12-01

11

Simulation of roll grinding system dynamics with rotor equations and speed control  

Science.gov (United States)

A nonlinear dynamical model for paper machine roll grinding process is investigated through a group of delay differential equations with one constant time-delay. In this model, the time-delay effect is originated from shape error traces on the surface of the roll. The contact interaction of the roll and the grindstone is based on the wear theory, and the lateral deformations of the roll as a simply supported continuous beam element inside a rotational coordinate frame and the rotational rigid body vibration system are considered. The PD-controllers of the roll and the grindstone drives are also included. The numerical simulations for time-history responses provide a view of the stability of this grinding process for the design, analysis and verification of industrial roll grinding measurements in future.

Yuan, Lihong; Järvenpää, Veli-Matti; Keskinen, Erno; Cotsaftis, Michel

2002-09-01

12

Heavy metals adsorption on rolling mill scale  

International Nuclear Information System (INIS)

A great quantity of industries are responsible for contaminating the environment with the heavy metals which are containing in their wastewaters. The recovery of these metals is both from an environmental and economical points of view of the upmost interest. A study is made of the use of mill scale-originating in the hot rolling of steel-as an adsorbent for the removal of heavy metals from liquid effluents. The adsorption of Zn''2+, Cd''2+ y Pb''2+ on the rolling mill scale was investigated by determination of adsorption isotherms. The effect of time, equilibrium temperature and concentration of metal solution on mill scale adsorption efficiency was evaluated. The adsorption process was analysed using the theories of Langmuir and Freundlich. Desorption process of metals from loaded mill scales was also studied using several doser bent at different experimental conditions. It has been proved that the mill scale is an effective adsorbent for the cations studies in aqueous solutions within the range of the working concentrations. (Author) 32 refs

2003-01-01

13

Metallurgical analysis of spalled work roll of hot strip mill  

International Nuclear Information System (INIS)

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

1993-01-01

14

Analysis of roll stack deflection in a hot strip mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Predictive models are required to provide the bending set point for bending for the flatness control devices at rolling stands of finishing mill of Hot Strip Mill (HSM). A simple model for roll stack deflection at the finishing mill has been illustrated where a modified Misaka’s equation has been used to obtain mean flow-stress. Investigation has been performed to understand the effect of width of roll on roll stack deflection. The bending on the deflection has been found to have a positive...

Sudipta Sikdar; Shylu John; Ashwin Pandit; Raju Dasu

2007-01-01

15

Structural causes of defects in a cast iron mill roll  

Directory of Open Access Journals (Sweden)

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

16

The roller grinding mill - its history and current situation. Pt. 1. Die Waelzmuehle - Geschichte und heutiger Stand. T. 1  

Energy Technology Data Exchange (ETDEWEB)

The history of the development of the roller grinding mill from its origins to the start of its industrial use is described with examples. The types of mill now on the market, their inventors and the companies which developed them are introduced. An explanation is given of the different forms of grinding bodies and their origins, and of the particular advantages of the roller grinding mill. The article closes with an example of the design. (orig.).

Brundiek, H. (Loesche GmbH, Duesseldorf (Germany, F.R.))

1989-10-01

17

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

1997-01-01

18

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

Directory of Open Access Journals (Sweden)

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

Łysiak G.

1997-12-01

19

Weibull statistical analysis of grinding element wear in ring-and-ball mills  

Energy Technology Data Exchange (ETDEWEB)

This paper demonstrates the use of the Weibull extreme value distribution as an alternative means to that of laboratory simulation and empirical correlation, for describing wear processes, and predicting wear life from limited wear data. As such, this approach was used to examine the wear rate of grinding elements in ring-and-ball coal grinding mills. Values obtained for the Weibull parameters were interpreted in terms of the contact geometries between grinding surfaces, and in terms of a sliding wear, constant wear rate model.

Spero, C.

1990-01-01

20

Investigation on the dependence of a quern mill output on the size of grinding slot and grain moisture  

Directory of Open Access Journals (Sweden)

Full Text Available The present paper presents the results of investigations on the process of wheat grinding in a grinding machine in the aspect of a simultaneous determination of the influence of material moisture and grinding slot onto the output of the grinding machine. The model of the grinding process is described. The model allowed to develop the equation of the machine output in relation to the working slot and grain moisture content. An increase of the slot size increases also the output of the grinding process. An in- crease in material moisture level decreases the process output. Exceeding the moisture of 16% caused stucking of the mill.

Opielak M.

1999-12-01

 
 
 
 
21

Statistical model and control of a ring-and-roller type grinding mill  

Energy Technology Data Exchange (ETDEWEB)

This project explores the use of a ring-and-roller grinding mill for fine grinding or pulverizing. Since the efficiency of this system is low, small improvements in product throughput or energy consumption can result in substantial economic improvements. To better understand this system, experiments were conducted for limestone and cement clinker. From these experiments models were formulated for product throughput, energy consumption and product size distribution. A control loop was implemented to reduce the effect of non-uniform feeding. Steady-state interactions were analyzed using the Relative Gain Array (RGA) method. Next, a multi-input and multi-output (MIMO) control system was designed using the Inverse Nyquist Array (INA) method to remove variable interactions. The robustness of this controller was explored. Finally, a self-tuning PI controller was designed using the pole placement method to improve system performance. The results of this study provide models for implementation on ring-and-roller grinding mills.

Cho, S.

1992-01-01

22

Performance characteristics of mill rolls from graphite chromium cast iron  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The main requirements for the development of a new grade for the later finishing section of the mill are : good oxidation and thermal behaviour, high wear resistance, good resistance to rolling incidents. The approach of Marichal Ketin to improve the rolling performances in the last finishing stands is presented. The Hi-Cr cast iron possesses excellent wear resistance due to the presence of hard chromium carbides, but its thermal conductivity and sticking properties are fairly low. A graphite...

Lecomte-beckers, Jacqueline; Terziev, L.; Breyer, J. P.

2000-01-01

23

Corrosion of Cast Iron Mill Plates in Wet Grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Andrews, Anthony; Kwofie, Samuel

2010-01-01

24

Corrosion of Cast Iron Mill Plates in Wet Grinding  

Directory of Open Access Journals (Sweden)

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

Anthony ANDREWS

2010-12-01

25

Behavior of grinding media in sand mill (I)  

Energy Technology Data Exchange (ETDEWEB)

Crushing or dispersion by a media in a sand mill is regarded to be carried out by the collision and shearing among the media, although its mechanism has seldom been examined. In this study, a two-dimensional model of a vertical disc type mill was trial made to be equipped with a concentric disc or with an eccentric disc which were observed using a video camera to measure the flow pattern and the velocity distribution of the media as well as its self rotation. In the concentric disc, the media showed a movement and at speed roughly in the tangential direction; self rotation of the media occurred at the end of the disc and its vicinity. Direction of the self rotation was mainly in the tangential direction in the horizontal section, and in the vertical direction to it. In the case of an eccentric disc, the movement and the direction of the media were not only tangentially, but also in the radial direction. As a conclusion, the eccentric disc mill is effective for crushing, dispersion and mixing of a sand mill as it moves the media in various directions. 4 refs., 11 figs., 1 tab.

Gondo, Toyohiko; To, Michiharu; Murakami, Yasuhiro (Kurume College of Technology, Fukuoka (Japan); Kyushu Univ., Fukuoka (Japan))

1989-04-20

26

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

Directory of Open Access Journals (Sweden)

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

Stephen Adegbite

2012-10-01

27

Variable-speed drive and control systems for rolling mills; Atsuenkiyo drive seigyo system  

Energy Technology Data Exchange (ETDEWEB)

The drive systems of large rolling mills is of a cycloconverter type, a GTO (gate turn-off thyristor) type or high-voltage IGBT (insulated gate bipolar transistor) type. Drive systems for bar, rod and pipe mills use three and/or two level IGBT inverters. This paper describes recent technical trends of drives and control systems in rolling mills, including each drive application and the PLC (programmable controller) and HCI (human communication interface) controlling the total rolling mill line. (author)

Kasai, T.; Tochigi, T. [Fuji Electric Co. Ltd., Tokyo (Japan)

2000-11-10

28

Recycle of valuable products from oily cold rolling mill sludge  

Science.gov (United States)

Oily cold rolling mill (CRM) sludge contains lots of iron and alloying elements along with plenty of hazardous organic components, which makes it as an attractive secondary source and an environmental contaminant at the same time. The compound methods of "vacuum distillation + oxidizing roasting" and "vacuum distillation + hydrogen reduction" were employed for the recycle of oily cold rolling mill sludge. First, the sludge was dynamically vacuum distilled in a rotating furnace at 50 r/min and 600°C for 3 h, which removed almost hazardous organic components, obtaining 89.2wt% ferrous resultant. Then, high purity ferric oxide powders (99.2wt%) and reduced iron powders (98.9wt%) were obtained when the distillation residues were oxidized and reduced, respectively. The distillation oil can be used for fuel or chemical feedstock, and the distillation gases can be collected and reused as a fuel.

Liu, Bo; Zhang, Shen-gen; Tian, Jian-jun; Pan, De-an; Liu, Yang; Volinsky, Alex A.

2013-10-01

29

Optimization of a Heavy Continuous Rolling Mill System Via Simulation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Ali Azadeh; Farid Ghaderi

2006-01-01

30

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

31

Modelling for control of a steckel hot rolling mill  

Energy Technology Data Exchange (ETDEWEB)

In this work the derivation of a nonlinear plant simulator of a Steckel Hot Rolling Mill process is shown. The simulator reflects the thickness crown and tension behaviour of the strip, while the temperature, shape and flatness behaviour of the strip fall outside the scope of this work. Roll gap, stand, tension and hydraulic actuator models are incorporated in order to yield the simulator. The nonlinear simulator is used to identify a linear model for control system design. The linear model was identified at a certain operating point associated with a particular pass of a multiple pass rolling schedule. Step tests were applied to the manipulated variables of the simulator, and using system identification (SID) techniques a linear time invariant (LTI) multivariable input output (MIMO) transfer function model was identified. Lastly an initial control problem is formulated. (author)

Scholtz, E.

2000-10-01

32

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

Science.gov (United States)

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

Tassinari, T; Macy, C

1977-09-01

33

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

34

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.

35

Effect of hot rolling lubrication in a pilot plant mill - Second experimental report  

Energy Technology Data Exchange (ETDEWEB)

Experiments with hot rolling lubrication in a pilot plant rolling mill have been carried out at MEFOS (Foundation for metallurgical research) Metal Working Research Plant. The rolling was carried out as a controlled rolling in 930 deg C and 880 deg C and as a conventional rolling on Nb-alloyed steel billet which were flat rolled to 12 mm, 8 mm, 6 mm and 5 mm thickness. The influence of lubrication on the rolling force and torque in controlled rolling is smaller than that in conventional rolling, when the rolling product thickness is 5 mm and 6 mm. Around max. 20% rolling force decrease was achieved in conventional rolling. The effect of lubrication is related to the L/H value, but due to the scale which was formed during the holding period in controlled rolling the effect of lubrication was decreased in controlled rolling. According to the results of the test, the economic benefit is analysed when using lubricant in controlled rolling and conventional rolling. The possibility of using hot rolling lubricant in controlled rolling in a weak rolling mill is also discussed.

Jarl, M.; Li Xiaoyu

1988-09-30

36

Use of a finite element method to calculate roll profiles for broad-strip mills  

Science.gov (United States)

A model is proposed to calculate the polishing profiling of rolls in broad-strip mills using a finite element method, and it is applied to develop new roll profiles. The finite element method is used to determine the polishing profiling of a roll with a complex shape, which substantially decreases the nonuniformity of reduction and drawing over the strip width. This profiling can be executed on numerical control roll grinders.

Garber, E. A.; Bolobanova, N. L.; Traino, A. I.

2012-05-01

37

Preparation and properties of barium ferrite using hot-rolled mill scale  

Energy Technology Data Exchange (ETDEWEB)

Commercial-quality barium ferrite was made on a laboratory scale by the solid-state reaction of raw hot-rolled mill scale and barium carbonate. The processing parameters are reported. The mechanism of ferrite formation is proposed.

Chien, Y.T.; Pan, H.C.; Ko, Y.C. (China Steel Corp., Kaohsiung, Taiwan (TW))

1989-08-01

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

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

40

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

International Nuclear Information System (INIS)

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

2011-09-01

 
 
 
 
41

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

Science.gov (United States)

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

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

2011-04-27

42

Study on the improved accuracy of strip profile using numerical formula model in continuous cold rolling with 6-high mill  

International Nuclear Information System (INIS)

The quality requirements for thickness accuracy in cold rolling continue to become more stringent. In cold rolling mill, it is very important that the rolling force calculation considers rolling conditions. The rolled strip thickness was predicted using calculated rolling force. However, the prediction of strip thickness in cold rolling is very difficult; in particular, for 6-high mill with shifted intermediate roll (IMR), the accuracy of thickness is not good. In this study, to improve the accuracy of rolled strip thickness, the roll gap flattening can be given based on Hertz contact theory, with contact between rolls and the smooth cylindrical rolls for the rolling elastic deformation. Also, the distribution of the roll gap flattening may be calculated using the contact force of unit transverse length. The strip profile at the continuous cold rolling is calculated by using the numerical analysis model considering the initial strip profile before cold rolling. Hence, we propose that the numerical model can predict the rolled strip profile more quickly and accurately and be applicable to the field. The results of the proposed numerical model were verified by FE-simulation and cold rolling experiments of 6-high mill with five stands

2011-08-01

43

Study on the improved accuracy of strip profile using numerical formula model in continuous cold rolling with 6-high mill  

Energy Technology Data Exchange (ETDEWEB)

The quality requirements for thickness accuracy in cold rolling continue to become more stringent. In cold rolling mill, it is very important that the rolling force calculation considers rolling conditions. The rolled strip thickness was predicted using calculated rolling force. However, the prediction of strip thickness in cold rolling is very difficult; in particular, for 6-high mill with shifted intermediate roll (IMR), the accuracy of thickness is not good. In this study, to improve the accuracy of rolled strip thickness, the roll gap flattening can be given based on Hertz contact theory, with contact between rolls and the smooth cylindrical rolls for the rolling elastic deformation. Also, the distribution of the roll gap flattening may be calculated using the contact force of unit transverse length. The strip profile at the continuous cold rolling is calculated by using the numerical analysis model considering the initial strip profile before cold rolling. Hence, we propose that the numerical model can predict the rolled strip profile more quickly and accurately and be applicable to the field. The results of the proposed numerical model were verified by FE-simulation and cold rolling experiments of 6-high mill with five stands.

Lee, Sang Ho; Kim, Byung Min [Pusan National University, Busan (Korea, Republic of); Song, Gil Ho; Lee, Sung Jin [POSCO, Pohang (Korea, Republic of)

2011-08-15

44

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.

Gálvez J. M.

2003-01-01

45

Genera use of CBN in tool grinding: Technology and economics  

Science.gov (United States)

A long term test program in which all the grinding processes technically capable of being converted from conventional abrasives to crystalline boron nitrides (CBN) was carried out in close cooperation with an abrasives manufacturer and a tool manufacturer whose production included all types of cutters; notably, hobs, profile cutters, side melting cutters, and face milling cutters, as well as crushing rolls for profiling grinding wheels. The material mainly used was EM05C05 confirming to S 6-5-2-5.

Meyer, H. R.; Wiemann, H. J.

46

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)

2000-08-20

47

Actuator fault detection, isolation method and state estimator design for hot rolling mill monitoring  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a method for actuator fault diagnosis in a speed control loop of a hot roughing rolling mill used to carry out multi-pass forward-forward or forward-reverse rolling. The main objectives of the work is to first improve an actuator fault detection and fault magnitude estimation problem for a particular system and second to estimate non measurable variables in order to provide suitable information to the monitoring system. According to fault diagnosis theory and the specific ...

Theilliol, Didier; Mahfouf, Mahdi; Sauter, Dominique; Gama, Miguel Angel

2006-01-01

48

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

49

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

50

Merging of advices from multiple advisory systems - with evaluation on rolling mill data.  

Czech Academy of Sciences Publication Activity Database

multiple-participant decision-makingKód oboru RIV: BC - Teorie a systémy ?ízení http://library.utia.cas.cz/separaty/2009/AS/andrysek-merging of advices from multiple advisory systems-with evaluation on rolling mill data.pdf

Ettler, P.; Andrýsek, Josef; Šmídl, Václav; Kárný, Miroslav

51

Motion of grinding media in axial direction and its effect on comminution in an agitation beads mill; Baitai kakuhangata model funsaiki ni okeru baitai no jikuhoko undo to funsai koka  

Energy Technology Data Exchange (ETDEWEB)

Grinding tests were carried out using a model agitation beads mill with a single disc. Four different discs were used to examine the effect of the motion of the grinding media in the axial direction. The median diameter of the ground products decreased with increasing movement of the grinding media in the axial direction under the same degree of filling of the grinding media and speed of rotation. Contamination in the product from the agitating element and grinding vessel increased with increasing energy input, irrespective of the shape of the agitating disc. Contamination from the grinding media increased with increase in the movement of grinding media in axial direction. The motion of grinding media in the axial direction is concluded to cause mutual collision and hence to increase abrasion of the grinding media. 8 refs., 10 figs.

Hashi, Y. [Ashizawa Ltd., Chiba (Japan); Senna, M. [Keio University, Tokyo (Japan). Faculty of Science and Technology

1995-05-10

52

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

Directory of Open Access Journals (Sweden)

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

J. Krawczyk

2010-07-01

53

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.

54

Actuator/sensor fault diagnosis for an experimental hot rolling mill - A case study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a method for actuator/sensors fault diagnosis in a speed control loop of a hot roughing rolling mill used to carry out multi-pass forward-forward or forward-reverse rolling. According to fault diagnosis theory and the specific application domain, the main objective of the work is to develop a model-based fault detection filter combined with a conventional Luenberger observer. Based on an appropriate gain, the developed technique enables to supervise the hot roughing rollin...

Theilliol, Didier; Mahfouf, Mahdi; Sauter, Dominique; Ponsart, Jean-christophe

2006-01-01

55

Heavy metals adsorption on rolling mill scale; Adsorcion de metales pesados sobre cascarill de laminacion  

Energy Technology Data Exchange (ETDEWEB)

A great quantity of industries are responsible for contaminating the environment with the heavy metals which are containing in their wastewaters. The recovery of these metals is both from an environmental and economical points of view of the upmost interest. A study is made of the use of mill scale-originating in the hot rolling of steel-as an adsorbent for the removal of heavy metals from liquid effluents. The adsorption of Zn''2+, Cd''2+ y Pb''2+ on the rolling mill scale was investigated by determination of adsorption isotherms. The effect of time, equilibrium temperature and concentration of metal solution on mill scale adsorption efficiency was evaluated. The adsorption process was analysed using the theories of Langmuir and Freundlich. Desorption process of metals from loaded mill scales was also studied using several doser bent at different experimental conditions. It has been proved that the mill scale is an effective adsorbent for the cations studies in aqueous solutions within the range of the working concentrations. (Author) 32 refs.

Lopez, F. A.; Martin, M. I.; Perez, C.; Lopez-Delgado, A.; Alguacil, E. J.

2003-07-01

56

Investigation on the dependence of a quern mill output on the size of grinding slot and grain moisture  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present paper presents the results of investigations on the process of wheat grinding in a grinding machine in the aspect of a simultaneous determination of the influence of material moisture and grinding slot onto the output of the grinding machine. The model of the grinding process is described. The model allowed to develop the equation of the machine output in relation to the working slot and grain moisture content. An increase of the slot size increases also the output of the grindin...

1999-01-01

57

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...

2001-01-01

58

Wireless Remote Monitoring System for the Agc Svibration Fault of Rolling Mill  

Directory of Open Access Journals (Sweden)

Full Text Available The rolling mill screw down AGC system sets several subsystems of machinery, electronics, hydraulics, controls in one. Under the action of responding extreme frequency or external disturbances, the non design objective coupling between the subsystems may be excited, and causing the most serious vibration, seriously impact product quality or even cause great destruction. Aiming at the defects in fault diagnosis and control system of the traditional rolling mill, the wireless remote monitoring system for the rolling mill AGC system vibration fault is designed in this paper. Using the advanced sensor technology, PLC and configuration software, GPRS network technology, the parallel distributed data acquisition and data processing for the key servo element and the hydraulic parameters which can characterize the fault characteristics of the system can be done. The monitoring software system platform on line of the hydraulic AGC system based on Kingview is set up for centralized real-time monitoring. According to the collected multidisciplinary parameter the fault identification and location is done by using the fault diagnosis expert system based on Web, thus to make the preliminary evaluation for the operation and fault of hydraulic AGC system and provide advanced prediction and exclude strategy.

Yan Gao

2013-01-01

59

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

60

Hot sheet rolling on continuous mill under plastic fluid friction conditions. [12Kh18N10T  

Energy Technology Data Exchange (ETDEWEB)

A technique for hot sheet rolling in plastic fluid friction conditions of sheets of the 12Kh18N10T and carbon 10 sp steels is developed and tested. A new lubricant ''Silicatherm'' constitutes the basis of the technique. The advantages of the given technique as compared to the rolling with liquid lubricants of mineral and vegetative origin as well as the prospects of its introduction during hot rolling on continuous mills are shown.

Kolmogorov, V.L.; Spasskii, Yu.I.; Serebryakov, A.V.; Gindin, A.Sh.; Shavkun, V.V. (Ural' skii Politekhnicheskij Inst., Sverdlovsk (USSR))

1981-01-01

 
 
 
 
61

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper investigates gamma-alumina slurry preparation in a stirred media mill to develop protocols for the characterisation of slurries for coating onto monolithic catalyst supports. The relationship between the pH and the zeta potential of particles is determined. The gamma–alumina particles are found ...

Stephen Adegbite

2012-01-01

62

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The cast-iron rolls must present higher hardness at the rolling surface and lower in the core and the necks, adequate with mechanical resistance and in the high work temperature. If in the zone of the rolling surface, the hardness is guarantied by the irons structure, through the cementite quantities, the core of rolls must contain graphite, to assure this property. Starting from the lamination equipments aspects, from the form of rolls, of the technological interest zones and the structure, ...

Kiss, I.

2008-01-01

63

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

64

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

65

Rolling of bars and sections of fire-resisting metals on mills with noulti-shaft calibers  

International Nuclear Information System (INIS)

Summarized in this paper are the results of experimental studies and rolling of rods and sections from metal-ceramic and cest molybdenum and tungsten. The technical characteristics of the new MK-200 laboratory mill are given together with the calibaration scheme of tungsten and molybdenum rods

1976-01-01

66

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

Energy Technology Data Exchange (ETDEWEB)

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.

Kaper, T.J.; Wiggins, S. (California Inst. of Tech., Pasadena, CA (USA))

1989-01-01

67

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.

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

68

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

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

Evaluation of residual uranium contamination in the dirt floor of an abandoned metal rolling mill.  

Science.gov (United States)

A single, large, bulk sample of uranium-contaminated material from the dirt floor of an abandoned metal rolling mill was separated into different types and sizes of aliquots to simulate samples that would be collected during site remediation. The facility rolled approximately 11,000 tons of hot-forged ingots of uranium metal approximately 60 y ago, and it has not been used since that time. Thirty small mass (? 0.7 g) and 15 large mass (? 70 g) samples were prepared from the heterogeneously contaminated bulk material to determine how measurements of the uranium contamination vary with sample size. Aliquots of bulk material were also resuspended in an exposure chamber to produce six samples of respirable particles that were obtained using a cascade impactor. Samples of removable surface contamination were collected by wiping 100 cm of the interior surfaces of the exposure chamber with 47-mm-diameter fiber filters. Uranium contamination in each of the samples was measured directly using high-resolution gamma ray spectrometry. As expected, results for isotopic uranium (i.e., U and U) measured with the large-mass and small-mass samples are significantly different (p 0.05) from results for the large- or small-mass samples. Large-mass samples are more reliable for characterizing heterogeneously distributed radiological contamination than small-mass samples since they exhibit the least variation compared to the mean. Thus, samples should be sufficiently large in mass to insure that the results are truly representative of the heterogeneously distributed uranium contamination present at the facility. Monitoring exposure of workers and the public as a result of uranium contamination resuspended during site remediation should be evaluated using samples of sufficient size and type to accommodate the heterogeneous distribution of uranium in the bulk material. PMID:23274821

Glassford, Eric; Spitz, Henry; Lobaugh, Megan; Spitler, Grant; Succop, Paul; Rice, Carol

2013-02-01

71

Birefringent Strands in Polymer Flows in a Co-rotating Two-Roll Mill  

Science.gov (United States)

We study flow of polymer solutions in a co-rotating two-roll mill. Polymer molecules are significantly extended downstream of an isolated stagnation point in the nip, creating a "birefringent strand" visible through optical experiments. The elastic stress created by the strand is approximated by a line of discontinuity in shear stress. Since the height of the nip is small in comparison to the radius of the rollers, the lubrication approximation is used for the flow and pressure fields. The tangential stress condition and conservation of flux across the nip are used to obtain ordinary differential equations for U(x), the velocity on the strand, p_x, the pressure gradient, and l(x), the position of the strand. Integration of the equations subject to boundary and integral conditions yields solutions for the strand position and velocity as functions of s, the ratio of roller speeds, and ?, a non-Newtonian parameter dependent on the the polymer concentration, maximum length, and the Deborah number. The numerical results compare well with experimental observations of l(x).

Lee, Isaac; Homsy, George

1999-11-01

72

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-03-15

73

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-07-01

74

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

Directory of Open Access Journals (Sweden)

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

Laerte José Fernandes

2013-03-01

75

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

Directory of Open Access Journals (Sweden)

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

Laerte José Fernandes

2012-01-01

76

Micromill designed for the measurement of the wheat kernel grinding resistance, in the grinding process  

Directory of Open Access Journals (Sweden)

Full Text Available In the era of global slowdown and recession, saving energy becomes a ”must have” characteristic of every industrial consumer. In the industrial milling process of the wheat, 60-75 % of the total specific energy consumption is used in the grinding process. The measurement of the grinding resistance of the wheat kernel can estimate the energy consumption in the grinding process and can lead to a diminution of the total energy consumption, in the milling process.

Ioan DANCIU

2010-12-01

77

Micromill designed for the measurement of the wheat kernel grinding resistance, in the grinding process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the era of global slowdown and recession, saving energy becomes a ”must have” characteristic of every industrial consumer. In the industrial milling process of the wheat, 60-75 % of the total specific energy consumption is used in the grinding process. The measurement of the grinding resistance of the wheat kernel can estimate the energy consumption in the grinding process and can lead to a diminution of the total energy consumption, in the milling process.

2010-01-01

78

Expert system for flatness control in aluminum foil rolling. Alumi haku mill keijo seigyo expert system  

Energy Technology Data Exchange (ETDEWEB)

This paper reports the application of an expert system for Automatic Flatness Control (AFC) in aluminum foil rolling. The expert system is connected with AFC, and adjusts the target shape pattern according to the material characteristics and the operating conditions. This system is developed on the UNIX work station, and consists of six units, three knowledge bases, and a working memory. It has shown the ability to improve all kinds of aluminum foil throughout an one year adaptation in the operational rolling process. By using this system, the speed of rolling was improved above 10 percent. The algorithm which maintains consistency among multiple control purposes and the adaptive inference method realized in this system proved to be useful as a paradigm of the knowledge base system for the control process. 1 ref., 6 figs.

Konishi, M.; Nose, K.; Narazaki, H.; Iwatani, T.; Oshima, H.; Kitagawa, S. (Kobe Steel, Ltd., Kobe (Japan))

1990-07-01

79

Width variation defects reducing measurements at the hot rolling mill II; Medidas tomadas para reducao do defeito variacao de largura no LTQ-II  

Energy Technology Data Exchange (ETDEWEB)

This paper shows the results of the productivity gains on the rolling mill, caused by the increase of the fine adjusting on the chair activity, as well the standardization of the lopper`s working angle. 1 ref., 12 figs., 1 tab.

Tirello, Jonas; Dornelas, Francisco C.; Brandao, Jose M.M.; Vilella, Marcelo; P. Neto, Arlindo F.; Nardeli Sobrinho, Antonio [Companhia Siderurgica Nacional, Volta Redonda, RJ (Brazil)

1991-12-31

80

Alteration of sepiolite by dry grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Cornejo, J.; Hermosin, M. C.

1987-01-01

 
 
 
 
81

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

In wheat milling, it is particularly necessary that the grist particle size-distribution entering and exiting each plansifter compartment of the wheat mill to be determined so that the appropriate geometrical characteristics of flutes, grinding rolls and their functional parameters can be chosen and the characteristics of the sieves braids to be established to optimize flour, middling, and semolina yield and quality of them. The paper presents the particle size-distribution of wheat going thr...

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

2013-01-01

82

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

Scientific Electronic Library Online (English)

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

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

83

Lipoid pneumonia caused by oil mist exposure from a steel rolling tandem mill  

Energy Technology Data Exchange (ETDEWEB)

Five of nine active tandem mill operators exposed at work to aerosolized hydrocarbon mist were referred for evaluation of respiratory complaints. The worker with the longest exposure had reduced lung volumes; he was admitted to the hospital for detailed study. Exercise studies revealed work load limited by ventilation and arterial oxygen desaturation. Flexible fiberoptic bronchoscopy with bronchoalveolar lavage and transbronchial biopsy revealed evidence of lipoid pneumonia. Assessment of the mill revealed levels of respirable oil mist by personal samplers throughout the area far below the currently accepted standard of 5 mg/M3. These findings confirm a 20-year-old hypothesis of J.G. Jones regarding the hazard of oil mist in this industrial setting.

Cullen, M.R.; Balmes, J.R.; Robins, J.M.; Smith, G.J.

1981-01-01

84

Cost efficiency of a rolling mill furnace as a function of soaking action  

Energy Technology Data Exchange (ETDEWEB)

The maximum temperature difference shortly prior to discharge from the furnace is one of the main criteria in the reheating of slabs to be rolled into sheet. Experience has shown that in contrast to slow heating and short soaking it is preferable to heat the stock rapidly to the desired surface temperature and to keep it at this value for a prolonged period if satisfactory soaking action is to be achieved. However, conditions are reversed when it comes to the cost efficiency of the furnace. The correlations between soaking action and cost efficiency are analysed.

Behrens, H.A.

1984-04-01

85

"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

86

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

Scientific Electronic Library Online (English)

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

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

87

Sheet production using powder rolling of nickel and titanium alloys  

International Nuclear Information System (INIS)

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

1975-01-01

88

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 retrospe...

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

2009-01-01

89

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

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

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.)

1983-01-01

92

Energy Use of Fine Grinding in Mineral Processing  

Science.gov (United States)

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

de Bakker, Jan

2013-12-01

93

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

94

Experiments for choosing the optimal mill type for grinding the middling product in Romania; Versuche zur Auswahl des optimalen Muehlentyps beim Mahlen von Steinkohlengemisch in Rumaenien  

Energy Technology Data Exchange (ETDEWEB)

The hard coal used in Romanian power plants is practically a middling product from the preparation of hard coal for coking. This fuel is characterized by a relatively high ash and moisture content. To be noticed is the high dispersion of the properties. The tests carried out in the test plant confirm the assumption that the different mill designs behave differently on milling various solid fuels. Such a test plant therefore proved to be useful at the operator of roller mills - especially as no experience in the field of selection and operation of such mills is available. (orig.) [German] Bei der in den rumaenischen Kraftwerken eingesetzten Steinkohle handelt es sich praktisch um ein Mittelprodukt aus der Aufbereitung von Rohsteinkohle zur Verkokung. Dieser Brennstoff ist durch einen realtiv hohen Asche- und Feuchtegehalt gekennzeichnet. Beachtenswert ist die grosse Streuung der Kennwerte dieses Brennstoffes. Die in der Versuchsanlage durchgefuehrten Versuche bestaetigten die Annahme, dass sich verschiedene bautechnische Muehlenkonfigurationen beim Mahlen verschiedener Festbrennstoffe verschieden verhalten. Aus diesem Grund erwies sich eine solche Versuchsanlage beim Betreiber der Walzenmuehlen als nuetzlich - insbesondere bei fehlenden Erfahrungen auf dem Gebiet der Auswahl und des Betriebs solcher Muehlen. (orig.)

Chercea, G.; Mangu-Totolo, C.; Ispas, C.; Belausov, G. [RENEL-GSCI-ICEMENERG, Bukarest (Romania); Radulescu, M. [TERMICO GmbH, Bukarest (Romania)

1999-07-01

95

Ultrafine grinding. Chobifunsai gijutsu ni tsuite  

Energy Technology Data Exchange (ETDEWEB)

The progress of fine ceramics and other leading technology is accelerating the heightening in importance of ultrafine particulate production technology. Then, two to three new types of ultrafine grinder were developed with experimentation to effectively produce submicron particulate. One of them is an inclined ball mill, effectively utilizing three-dimensional space, or that which is further improved as a two-axis or three-axis inclined ball mill, excellent in mechanical balance. By being provided with a reciprocating movement in the direction of cylinder shaft in the grinding chamber as well as the movement in the rotating direction of mill, it became able to produce submicron particulate with grinding medium, made quick in movement. Particularly for the three-axis inclined ball mill, the fact, among others, that movement, at 30 to 60% of critical number of rotations, is appropriate with lowering in number of rotations of mill was elucidated. While, as an experimental result of developed disk mill, it was confirmed to have a possibility to become an ultrafine grinder, with heightening in number of rotations, able to shorten the grinding time. 29 refs., 19 figs., 1 tab.

Oya, Hitoshi; Yamamoto, Mitsuru; Sakamoto, Hiroshi (National Reseach Inst. for Pollution-and Resources, Tsukuba (Japan))

1989-12-25

96

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

97

An investigation of rolling pressure on metallic uranium rod  

Energy Technology Data Exchange (ETDEWEB)

An investigation of rolling pressure on metallic uranium rod was made. The behavior of uranium metal in rolling mills was considered as a viscous flow. Then the differential equation for rolling pressure was established. The calculation formula for rolling pressure was derived from the equation and theoretical calculation method for rolling pressure was given. Values of rolling pressure were calculated according to the calculation formula. Values of rolling pressure, coefficient of contact friction and lateral expansion of uranium rod were measured in rolling mills. The calculated rolling pressure was compared with that measured in rolling mills.

Meng, Z.

1984-01-01

98

Investigation of rolling pressure on metallic uranium rod  

Energy Technology Data Exchange (ETDEWEB)

The rolling pressure on metallic uranium rod was investigated. By considering the behavior of the uranium metal in a rolling mill as a viscous flow, the differential equation for the rolling pressure was established. A formula for calculating the rolling pressure was derived and the theoretical calculation method was given. The rolling pressure, the coefficient of contact friction, and the lateral expansion of uranium rod were measured. The measured rolling pressure was compared to the calculated value. Rolling is an important forming technique for uranium. A study of the rolling parameters of uranium serves as a basis for rolling mill design, engineering calculation, and rolling mill strength calibration.

Zhang, M.

1984-06-01

99

Development of the speed control unit of the hot rolling mill of the brazilian National Steel Company; Desenvolvimento do controle de correcao de velocidade do acabamento do LTQ-2 da CSN  

Energy Technology Data Exchange (ETDEWEB)

This work shows the development of a control system to correct the speed of the tandem hot rolling mill, by utilization of a mathematical model. A more reliable operational performance was reached with the application of this model at a computer set-up level. 4 figs.

Silveira, Aquiles A. da; Dornelas, Francisco C.; Ferreira, Emerson R.; Alves, Sergio C.; Miguez, Antonio C.P.; Brandao, Jose M.M.; Tirello, Jonas [Companhia Siderurgica Nacional, Volta Redonda, RJ (Brazil)

1991-12-31

100

Chloride and sulphate determination in the cold rolling mill emulsion. Iron and Steel Company of Sao Paulo State, Brazil; Determinacao de sulfato e cloreto na emulsao do laminador de tiras a frio Companhia Siderurugica Paulista (COSIPA), SP, Brazil  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the aqueous layer determination of the sulphate and chloride ions in the cold rolling mill emulsion. The results show that this method is reliable up 5,0 mg l for sulphate and 2,0 mg l for chloride. The method performance is very simple and it is been used from routine analysis. 7 tabs., 2 refs.

Aufiero, Alice A.M.; Peters, Patricia S.; Caires, Analia C.P.; Reinoldes, Joao [Associacao Brasileira de Metais (ABM), Sao Paulo, SP (Brazil)

1990-12-31

 
 
 
 
101

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

2010-12-01

102

Longitudinal Grinding of Aspen  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this thesis work was to find out the paper properties obtained from longitudinal grinding of aspen. Mechanical Pulping, longitudinal grinding and short description of studied paper properties were introduced in the theoretical part.

2011-01-01

103

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ra...

1990-01-01

104

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

105

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

106

Conduit grinding apparatus  

Energy Technology Data Exchange (ETDEWEB)

A grinding apparatus is disclosed 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. 2 figures.

Nachbar, H.D.; Korytkowski, A.S.

1991-06-11

107

Conduit grinding apparatus  

Energy Technology Data Exchange (ETDEWEB)

This invention is comprised of 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, H.D.; Korytkowski, A.S.

1990-01-01

108

Conduit grinding apparatus  

Energy Technology Data Exchange (ETDEWEB)

This invention is comprised of 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, H.D.; Korytkowski, A.S.

1990-12-31

109

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

110

One-touch cage mill  

Energy Technology Data Exchange (ETDEWEB)

Explanations and accompanying diagrams are given of the functions and construction of a 'one-touch' cage mill. Maintenance of the mill is very easy; the cage and liner can be easily replaced and inspection of the inside of the grinding compartment is simple. Detailed descriptions are given of the various features of the mill, including the power mechanism for opening the grinding compartment, the excellent wear resistance and grinding power of the cage, the grinding of high moisture content materials, the wide range of product particle sizes obtainable, and the compact construction and anti-dust design. The use of the mill is explained. High moisture content materials can be simultaneously mixed and pulverized.

Tazaki, M.

1983-01-01

111

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 working-layer were obtained for both of them, but the production cost of the WCP/Fe-C composites roller ring decreased by 50%.

2010-09-15

112

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

113

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

Directory of Open Access Journals (Sweden)

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

MILAN MITROVIC

2002-03-01

114

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  

Science.gov (United States)

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; Gadgil, Alaka S.; Ghole, Vikram. S.; Gore, Sharad D.; Jaafarzadeh, Neemat; Mirkazemi, Roksana

2009-01-01

115

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

116

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

CERN Multimedia

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

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

2000-01-01

117

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

International Nuclear Information System (INIS)

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

2010-10-01

118

Study on anaerobic treatment of hazardous steel-mill waste rolling oil (SmWRO) for multi-benefit disposal route.  

Science.gov (United States)

Steel-mill waste rolling oil (SmWRO) is considered as hazardous substance with high treatment and disposal fees. Anaerobic process could not only transform the hazardous substance into activated sludge, but also generate valuable biogas. This study aimed at studying the biochemical methane potential of SmWRO under inoculum to substrate VS ratios (ISRs) of 0.25, 0.5, 1, 1.5, 2 and 3 using septic tank sludge as inoculum in mesophilic and thermophilic conditions, with blank tests for control. Specific biogas yield (mL/g VS(added)), net biogas yield (mL/g VS(removed)) and VS removal were analyzed. The ANOVA results indicated great influence of ISR and temperature on studied parameters. ISR of 1.5 at 55°C and ISR of 1.5 and 2 at 35°C were suggested with the highest specific biogas yield (262-265 and 303mL/g VS(added)). Kinetic analysis showed that Gompertz model fit the experimental data best with the least RMSE and largest R(2). PMID:24212130

Ma, Huanhuan; Li, Zifu; Yin, Fubin; Kao, William; Yin, Yi; Bai, Xiaofeng

2014-01-01

119

Method and equipment for the grinding of material difficult to be ground, especially wet coal or coke. Verfahren und Vorrichtung zur Mahlung von schwermahlbarem Gut, insbesondere von feuchter Kohle oder Koks  

Energy Technology Data Exchange (ETDEWEB)

The grinding, according to the invention, takes place in a material bed on a grinding track by using a high specific pressure; the material to be ground is run over and carried away by grinding rolls between concentric, cylindrical grinding tracks one of which, preferably the inner one, is driven rotationally. (orig./RB).

Unger, G.

1985-11-07

120

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...

2011-01-01

 
 
 
 
121

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 turning 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 convert...

Rabiey, Mohammad

2011-01-01

122

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

123

Work index and grinding energy assessment of Dilband iron ore Pakistan  

International Nuclear Information System (INIS)

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

2011-01-01

124

ONLINE SAG MILL PULSE MEASUREMENT AND OPTIMIZATION  

Energy Technology Data Exchange (ETDEWEB)

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

Raj Rajamani; Jose Delgadillo; Vishal Duriseti

2006-06-24

125

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

International Nuclear Information System (INIS)

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

2009-10-15

126

Applications of High-Efficiency Abrasive Process with CBN Grinding Wheel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2010-01-01

127

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

128

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

129

Potentiality of Heat-Treated Balls in the Grinding of Gold Ores.  

Science.gov (United States)

A major investigation was made of the life and performance of heat-treated grinding balls in the 9 by 10 ft No. 1 ball mill at Libanon Gold Mine. The standard 100 mm cast semi-steel balls commonly used to grind gold ores are not suited to heat treatment. ...

D. D. Howat G. J. Wright

1983-01-01

130

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

Scientific Electronic Library Online (English)

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

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

131

Grinding and friction investigations about the hydrogen embrittlement of iron  

Energy Technology Data Exchange (ETDEWEB)

The crushing behavior of in H/sub 2/ tempered (between 773 K and 1173 K) and untempered iron and iron rich solid solutions are investigated in ball mills. Up to 773 K the solubility of H/sub 2/ in iron is retarded by an oxid-scale formation. Between 773 K and 1173 K the solving of H/sub 2/ is an exothermic reaction. The higher grinding speed shows that the diffusing H/sub 2/ embrittles the iron. When the grinding runs in an H/sub 2/-atmosphere additional H/sub 2/ diffuses into the ruptured crystals. As a consequence the embrittlement and the grinding speed is increasing. Theoretical reflection show that the high local temperature (ca. 1773 K) during the grinding process (friction heating) is responsible for the high H/sub 2/-solubility. The rewelding of the crushed material is retarded by adding Octan and Xylol.

Gidarakos, E.

1980-05-23

132

Industrial application of HCX-MILL to hot strip mills; Netsukan`yo HCX-MILL no jikki tokusei  

Energy Technology Data Exchange (ETDEWEB)

Hot-rolled steel is increasingly becoming harder and thinner. As a result, the first stand of a finishing mill is required to have expanded control capacity for fabrication of plate crowns, because control functions of the last stand are preferentially allocated to shaping. Hitachi Ltd. has been pursuing 4-stage high crown mill functions to meet the above requirement, and developed a new mill named HCX-MILL of high controlling capacity for plate crowns, in which only working rolls are crossed. Described herein are outline of the development of the mill and its functions. Crossing of working rolls alone is difficult for the conventional crown mill, because of an excessive thrust resulting from relative motion between the working and auxiliary rolls. A new inter-roll lubrication techniques have been developed to solve the above problem and realize crossing of the working rolls alone. The first commercial system has been exhibiting good plate crown controllability. 2 refs., 13 figs., 2 tabs.

Ono, H.; Watanabe, T. [Nisshin Steel Co. Ltd., Tokyo (Japan); Yoshimoto, K.; Kaga, S. [Hitachi, Ltd., Tokyo (Japan)

1996-06-01

133

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

134

CKP high capacity-up pre-grinding system and integral finish grinding system; CKP kozosan yofunsai system narabini zanfunsai system  

Energy Technology Data Exchange (ETDEWEB)

A CKP high capacity-up pre-grinding system for cement that is characterized by energy saving, night power application, and high capacity was developed. The fluidized separator used as a classifier that enables high-capacity processing and energy saving is incorporated into the system. The separator improves the grinding efficiency of a tube mill and classifies the fine particles to suppress the vibration of a CKP mill. This system is characterized by an increase in grinding capability, power saving, high-quality products, and high operation stability. To improve the quality of cement products and reduce the power of an exhaust fan, the integral finish grinding system was established using an existing roller mill plant. A closed circuit was formed using the external separator, CKP mill, and circulating transportation to reduce the fan power. The pulverized products in a CKP mill are not classified using a separator and partially returned to the CKP mill. Moreover, the particle size distribution of products can be adjusted by increasing the fine grinding in the pulverized products. As a result, the quality is improved. 4 figs., 2 tabs.

NONE

1996-07-20

135

Improved Jet-Mill Silicon Grinder  

Science.gov (United States)

Proposed refinement in jet-mill grinding of silicon reduces proportion of unusable, overly ground particles. Particles serve as seeds for growth of silicon from vapor. In new grinding apparatus, particle separator distinct from collision chamber. Particle collides only once before sorted for size. If proper size, extracted; if not, returned to chamber for another collision.

Collins, Earl R., Jr.

1986-01-01

136

Burrs produced by grinding  

Energy Technology Data Exchange (ETDEWEB)

An investigation was conducted to determine the influence of variables in controlling the size and repeatability of grinding burrs to minimize burr-removal costs and improve the quality and reliability of parts for small precision mechanisms. Each of the three types of burrs produced by surface-grinding a rectangular block responds differently to changes in cutting conditions. Reducing the downfeed rate generally produces shorter burrs. Although the size of the abrasive grain affected the thickness of one of the burrs, thickness was relatively unaffected by the variables studied. The thickest burrs occurred on low-carbon steel.

Gillespie, L.K.

1976-08-01

137

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

138

Impact grinding of damp materials ?????????? ??????? ?????????? ??????  

Digital Repository Infrastructure Vision for European Research (DRIVER)

According to the authors of the article, it has been proven that dry and damp materials crushed in grinders of the shock type demonstrate different grinding patterns. Therefore, there is a need to explore the influence of the moisture content produced on the efficiency of grinding. The most efficient grinding mode is the one that assures maximal probability of destruction. Centrifugal grinders were used to analyze the grinding process. The experimental data have proven that the probability of...

Ladaev Nikolay Mikhaylovich; Guyumdzhyan Perch Pogosovich; Zhbanova Elena Valentinovna

2012-01-01

139

Rolling and annealing texture in twin roll cast commercial purity aluminium  

Energy Technology Data Exchange (ETDEWEB)

The development of cold rolling and annealing texture in twin roll cast commercial aluminium has been studied, varying rolling conditions such as lubricant and rolling speed in laboratory rolling and by comparing laboratory rolled sheets to that from a commercial mill. The tendency to formation of shear texture in the surface of laboratory rolled sheets was promoted by high surface friction and low rolling speeds, while well lubricated rolls and high speeds resulted in a plane strain type texture also in the sheet surface. The latter was also typical of industrial rolling. The effect of the surface deformation mode and texture on the grain structure resulting from the subsequent annealing has also been studied. The shear texture in laboratory rolled sheets were associated with a smaller grain size than industrially rolled sheets. (orig.)

Benum, S. (SINTEF, Div. of Metallurgy, Trondheim (Norway)); Engler, O. (Inst. fuer Metallkunde und Metallphysik, RWTH Aachen (Germany)); Nes, E. (Norwegian Inst. of Tech., Dept. of Metallurgy, Trondheim (Norway))

1994-01-01

140

Stochastic Models of Solid Particles Grinding  

Directory of Open Access Journals (Sweden)

Full Text Available Solid particle grinding is considered as a Markov process. Mathematical models of disintegration kinetics are classified on the basis of the class of Markov process that they belong to. A mathematical description of the disintegration kinetics of polydisperse particles by milling in a shock-loading grinder is proposed on the basis of the theory of Markov processes taking into account the operational conditions in the device. The proposed stochastic model calculates the particle size distribution of the material at any instant in any place in the grinder. The experimental data is in accordance with the predicted values according to the proposed model.

G. A. Zueva

2010-01-01

 
 
 
 
141

Development of database and searching system for tool grinding  

Directory of Open Access Journals (Sweden)

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

J.Y. Chen

2008-02-01

142

Upgrading of cement grinding plants; Modernisation d'un atelier de broyage  

Energy Technology Data Exchange (ETDEWEB)

In cement manufacture, the cost of electricity is one of the highest cost items, typically 60% or more of the power is utilized for grinding. Ball or tube mills are still the most widely installed grinding equipment to be found in cement plants. They are extensively used for comminution of raw materials and coal and almost exclusively in finish grinding for cement. The efficiency of ball mills is low, only 3 to 6% of the power input is actually used for size reduction; the balance is simply wasted as heat, wear, vibration and noise. However, ball mills are simple to operate and maintain and have a high availability of 90 % or even more. The possibilities of optimising and upgrading bal mill grinding circuits have received considerable attention, especially during the last years. This has led to the development of high performance separators with integrated cement cooling, more advanced mill internals as well as pre-crushing equipment. This paper examines the factors affecting grinding performance and suggests a stepwise approach to optimise and upgrade existing cement grinding circuits by CPB technology. (authors)

Pichlmaier, E. [Christian Pfeiffer Maschinenfabrik GmbH (Germany)

2000-06-01

143

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

144

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

145

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

146

Low-Rank Coal Grinding Performance Versus Power Plant Performance  

Energy Technology Data Exchange (ETDEWEB)

The intent of this project was to demonstrate that Alaskan low-rank coal, which is high in volatile content, need not be ground as fine as bituminous coal (typically low in volatile content) for optimum combustion in power plants. The grind or particle size distribution (PSD), which is quantified by percentage of pulverized coal passing 74 microns (200 mesh), affects the pulverizer throughput in power plants. The finer the grind, the lower the throughput. For a power plant to maintain combustion levels, throughput needs to be high. The problem of particle size is compounded for Alaskan coal since it has a low Hardgrove grindability index (HGI); that is, it is difficult to grind. If the thesis of this project is demonstrated, then Alaskan coal need not be ground to the industry standard, thereby alleviating somewhat the low HGI issue (and, hopefully, furthering the salability of Alaskan coal). This project studied the relationship between PSD and power plant efficiency, emissions, and mill power consumption for low-rank high-volatile-content Alaskan coal. The emissions studied were CO, CO{sub 2}, NO{sub x}, SO{sub 2}, and Hg (only two tests). The tested PSD range was 42 to 81 percent passing 76 microns. Within the tested range, there was very little correlation between PSD and power plant efficiency, CO, NO{sub x}, and SO{sub 2}. Hg emissions were very low and, therefore, did not allow comparison between grind sizes. Mill power consumption was lower for coarser grinds.

Rajive Ganguli; Sukumar Bandopadhyay

2008-12-31

147

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

148

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

149

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

150

Applications of High-Efficiency Abrasive Process with CBN Grinding Wheel  

Directory of Open Access Journals (Sweden)

Full Text Available High-efficiency abrasive process with CBN grinding wheel is one of the important techniques of advanced manufacture. Combined with raw and finishing machining, it can attain high material removal rate like turning, milling and planning. The difficult-to-grinding materials can also be ground by means of this method with high performance. In the present paper, development status and latest progresses on high-efficiency abrasive machining technologies with CBN grinding wheel relate to high speed and super-high speed grinding, quick point-grinding, high efficiency deep-cut grinding, creep feed deep grinding, heavy-duty snagging and abrasive belt grinding were summarized. The efficiency and parameters range of these abrasive machining processes were compared. The key technologies of high efficiency abrasive machining, including grinding wheel, spindle and bearing, grinder, coolant supplying, installation and orientation of wheel and workpiece and safety defended, as well as intelligent monitor and NC grinding were investigated. It is concluded that high efficiency abrasive machining is a promising technology in the future.

Yan Zhou

2010-04-01

151

Slave to the grind  

Digital Repository Infrastructure Vision for European Research (DRIVER)

1. Monkey business / Bolan - Snake + 2. Slave to the grind / Bach - Bolan - Snake + 3. The threat / Bolan - Snake + 4. Quicksand Jesus / Bolan - Snake + 5. Psycho love / Bolan + 6. Get the fuck out / Bolan - Snake + 7. Livin' on a chain gang / Bolan - Snake + 8. Creepshow / Affuso - Bolan - Snake + 9. In a darkened room / Bach - Bolan - Snake + 10. Riot act / Bolan - Snake + 11. Mudkicker / Bach - Bolan - Hill + 12. Wasted time / Bach - Bolan - Snake

1991-01-01

152

A Tough Grind  

Science.gov (United States)

NASA's Mars Exploration Rover Spirit took the four images that make up this mosaic with its microscopic imager on sol 82. The mosaic reveals the drilled surface of the target called 'New York' on the rock dubbed 'Mazatzal.' The rock abrasion tool ground for 3 hours and 45 minutes to create this 3.8 millimeter-deep (0.15 inch) hole. The exposed area is 4.5 centimeters (1.8 inches) in diameter. Mazatzal was an interesting rock to grind because it has a lighter tone than the previously ground rocks 'Adirondack' and 'Humphrey,' and because it looks different from its surrounding environment. Scientists hypothesized that Mazatzal's surface might be covered with a rind of weathered material. They drilled through this very top layer to reveal the underlying rock. Because Mazatzal's surface was not even, the left half of the rock was penetrated more deeply than the right. As can be seen in this image, the right, darker portion of the rock is still covered by the rind material. Spirit completed a second grind at this location at a different angle to remove the remaining veneer from the right side and create an even deeper hole. Images of this second grind will be sent back to Earth in the next sol or two. After the Final Grind The image was acquired on sol 85 after the rover drilled into New York a second time with its rock abrasion tool. Remnants of the dark grey coating that covers Mazatzal's interior can be seen at the right side of the hole. The crack in the rock may have once contained fluids out of which minerals precipitated. Each image making up this mosaic is 3 centimeters (1.2 inches) across.

2004-01-01

153

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

154

Rolling Stonesi kinokontsert kannab toorest rokiväge / Maris Meiessaar  

Index Scriptorium Estoniae

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

Meiessaar, Maris

2009-01-01

155

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

156

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

157

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

158

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

159

Effects of pulpstone grits in wood grinding.  

Science.gov (United States)

Interest in grinding has increased in recent years as the demand for mechanical pulps has grown. The grinding process has been improved but little attention has been given to developing the pulpstones. Pressurized grinding and the need of energy preservat...

E. Sandaas

1991-01-01

160

Grinding mechanism of zirconia toughened alumina  

International Nuclear Information System (INIS)

In the grinding process, physical properties of ceramics affect both grinding mechanism and quality of ground surface. In this study we focused on fracture toughness of ceramics and the effect on grinding. A grinding test was carried out by single point grinding for ten different zirconia toughened alumina ceramics with different monoclinic zirconia contents. Effects of zirconia contents on the grinding mechanism and crack initiation were discussed. Copyright (1998) AD-TECH - International Foundation for the Advancement of Technology Ltd

1997-09-16

 
 
 
 
161

Longitudinal grinding of Norway spruce  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this bachelor’s thesis was to analyze the paper properties of Norway spruce (softwood) pulp which was made in two grinding ways and different longitudinal grinding angle for the paper making process. In the theoretical part, the fundamentals of mechanical pulping and the properties of Norway Spruce was introduced by Saimaa University of Applied Sciences, Imatra.

2011-01-01

162

VOLATILIZED LUBRICANT EMISSIONS FROM STEEL ROLLING OPERATIONS  

Science.gov (United States)

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

163

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)

2009-01-01

164

Online SAG Mill Pluse Measurement and Optimization  

Energy Technology Data Exchange (ETDEWEB)

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

Raj Rajamani; Jose Delgadillo; Vishal Duriseti

2007-06-30

165

New Technology in Metalworking Fluids and Grinding Wheels Achieves Tenfold Improvements in Grinding Performance.  

Science.gov (United States)

Metal manufacturing industries have a growing interest in finding economical ways to improve grinding productivity, part quality, and production cost. Our study extensively investigated the effects of the types of grinding wheels, grinding fluids, and the...

M. K. Kruegar S. C. Yoou D. Gong S. B. McSpadden L. J. Ourke R. J. Parten

2000-01-01

166

Electromechanical autogenous grinding of hard ferrites. Elektromechanische Autogenmahlung von Hartferriten  

Energy Technology Data Exchange (ETDEWEB)

Initial investigations on electromechanical autogenous milling show that the pulverization of ferrites in an EMAA is possible. Compared to conventional procedures, there is the advantage of performing grinding in one single step and without any working media. The analyses concerning the electromechanical autogenous hard ferrite milling in a laboratory setup have yielded slurries with a degree of dispersion of about 1.5 [mu]m. Here a throughput of 128 kg/h was able to be obtained at an energy consumption of 56 kWh/t. Thus the amount of energy consumed is only up to about 1/10 of the amount consumed by the procedures currently employed for the crushing of ferrites. Furthermore, the crushed ferrites can already be separated during the milling process. Another advantage is that the EMAA seems to be capable of being incorporated into the manufacturing technology without any substantial modifications. (orig.)

Halbedel, B. (Fakultaet Maschinenbau, Inst. Glas-/Keramik-Technik, Technische Univ. Ilmenau (Germany)); Killat, U.K. (Fakultaet Maschinenbau, Inst. Glas-/Keramik-Technik, Technische Univ. Ilmenau (Germany))

1993-10-01

167

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

168

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

1998-04-01

169

Two component grinding and liberation model and experimental studies of Cryogenic Tar Sand Separation  

Energy Technology Data Exchange (ETDEWEB)

Cryogenic Tar Sand Separation is a novel technique to access the vast energy potential of the Alberta Tar Sands. In this process tar sand is ground at about -50/sup 0/C. At this temperature the tar is more brittle and weaker than the sand. Thus, the tar is liberated from the sand and ground to fine particles, which can be separated from the sand. The technical performance of this process was studied, and a general grinding and liberation model was developed, which simulates this and two other component grinding processes. Four grinding/separation techniques were studied: Fluidized Bed Grinder (a stirred fluidized bed with steel balls) and Spouted Bed grinding combined with tar entrainment, and High Speed Impeller and Ball Mill grinding combined with sieving. The spouted bed gave the highest quality of separation, with a tar purity of 84%, at a tar recovery of 90%. The ball mill gave the lowest separation quality with a tar purity of 60% at 80% tar recovery, and 35% of 90% recovery. A maximum tar recovery of 94%, at a tar purity of 65%, was obtained in the fluidized bed grinder. The spouted bed gave the lowest rate of separation, with a typical processing time of 14 hours to obtain 90% tar recovery, versus 2-7 hours for the other mills. However, proposed modifications should increase this rate substantially.

Welmers, A.

1983-01-01

170

Improved coal grinding and fuel flow control in thermal power plants  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2011-01-01

171

Effect of TiC and TaC powder grinding on their structure  

International Nuclear Information System (INIS)

TiCsub(0.96) and TaCsub(0.98) carbides were subjects of investigation. Powders were grinded in a ball vibrating mill in ethanol under normal conditions during 3 h. Average size of particles was determined from anti Lsub(L) frequency and anti Lsub(V) volume distributions. It was shown that to characterise powder polydispersion, the distribution of particle size in anti Lsub(V) volume, and not in frequency, should be used; mean value of anti Lsub(V) reflects more completely the change of particle size of TiC and TaC during grinding. The deformation process during grinding depends on the aggregation degree of powder particles. Fine-structural properties of fine and coarse fractions of grinded material differ significantly

1982-10-01

172

Quality Improvement in the Production Process of Grinding Balls.  

Directory of Open Access Journals (Sweden)

Full Text Available The paper outlines how experiments were carried out to determine the optimum chromium/carbon (Cr/C ratio that brings the required hardness of 65HRC and to establish a quenching technique for the grinding balls. Matlab was also used to develop a mathematical model for the ball wear rate and its cost effectiveness basing on surface theory and volume theory. From the experimental results, the Cr/C ratio in the chemical composition 18:2 gave the required hardness. Also water quenched grinding balls gave the required hardness. The mathematical model was validated for both volume and surface theories using correlations of coefficients. The correlations of coefficients for both volume and surface theorems were 0.9994 and 0.9985 respectively and are all close to unity, which shows that both theories provide good descriptions of the way in which the masses of the balls decrease as a function of the amount of material milled.

Andrew Muzinda

2013-09-01

173

A grinding and drying installation  

Energy Technology Data Exchange (ETDEWEB)

A layout is proposed for a grinding and drying installation (PSU), which contains a feeder, a mixing heater for the recirculating drying agent, a fuel drying device, a ventable separator grinder with a cyclone dust trap, whose spout is connected with a dust hopper, linked by a moisture pump off pipeline with the grinder fan. The grinding and drying installation is distinguished by the fact that the dust spout from the cyclone to the hopper is equipped with a mixer with a branchpipe for feeding atmospheric air whose entry makes it possible to reduce the moisture content of the drying agent in the hopper. As a result of this it is possible to increase the maximal moisture level of the initial fuel from 10 to 15 percent without moisture formation in either the hopper or in other elements of the grinding and drying installation.

Antonenko, N.I.

1982-01-01

174

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1995-01-01

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 reloaded  

International Nuclear Information System (INIS)

Not so long ago a new observation about rolling motion was described: for a rolling wheel, there is a set of points with instantaneous velocities directed at or away from the centre of the wheel; these points form a circle whose diameter connects the centre of the wheel to the wheel's point of contact with the ground (Sharma 1996 Eur. J. Phys. 17 353-6). We provide a detailed experimental verification of this observation, collecting 3D data from a rolling wheel with a commercially available optical tracking system. We also extend the observation to a generalized form: for a rolling wheel, there is a set of points with instantaneous velocities directed at or away from any point P; these points form a circle whose diameter connects the point P to the wheel's point of contact with the ground. This generalization is also verified experimentally

2008-03-01

177

Particle size reduction of Si3N4 with Si3N4 milling hardware  

Science.gov (United States)

The grinding of Si3N4 powder using reaction bonded Si3N4 attrition, vibratory, and ball mills with Si3N4 media was examined. The rate of particle size reduction and the change in the chemical composition of the powder were determined in order to compare the grinding efficiency and the increase in impurity content resulting from mill and media wear for each technique. Attrition and vibratory milling exhibited rates of specific surface area increase that were approximately eight times that observed in ball milling. Vibratory milling introduced the greatest impurity pickup.

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

1986-01-01

178

Bruxism (Teeth Grinding or Clenching) (For Parents)  

Science.gov (United States)

... Parents > General Health > Your Kid's Teeth > Bruxism (Teeth Grinding or Clenching) Print A A A Text Size ... parents hear the harsher sounds of gnashing and grinding teeth, called bruxism , which is common in kids. ...

179

Mill’s Perfectionism  

Directory of Open Access Journals (Sweden)

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

PIERGIORGIO DONATELLI

2006-12-01

180

Automatic programming of grinding robot  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

1993-01-01

 
 
 
 
181

Impact grinding of damp materials ?????????? ??????? ?????????? ??????  

Directory of Open Access Journals (Sweden)

Full Text Available According to the authors of the article, it has been proven that dry and damp materials crushed in grinders of the shock type demonstrate different grinding patterns. Therefore, there is a need to explore the influence of the moisture content produced on the efficiency of grinding. The most efficient grinding mode is the one that assures maximal probability of destruction. Centrifugal grinders were used to analyze the grinding process. The experimental data have proven that the probability of destruction of damp samples is a lot higher than the one of dry samples, given the same initial dimensions of particles and the loading intensity. The rise in the probability of destruction is stipulated by the fact that that the grinder speed at which crushing is triggered is lower in case of damp samples than in case of dry ones. Expressions for speed that describes destruction initiation and the probability of destruction depending on the type of materials, the moisture content and the loading intensity have been derived.?????????? ???????????? ????????, ??? ??????????? ?????????? ???????? ????????? ????, ??? ??????. ?????????? ??????????? ?????????? ??????? ???, ??? ???????? ?????? ?????????? ??????? ?????????? ????????? ?? ????????? ? ??????.

Ladaev Nikolay Mikhaylovich

2012-06-01

182

Ultra-thin hot rolled strip; Gokuhaku atsukan atsuen kohan  

Energy Technology Data Exchange (ETDEWEB)

Kawasaki Steel has been making efforts to develop new hot-rolled steel products by using fully continuous rolling technology, so-called 'endless rolling', at No.3 hot strip mill of Chiba Works. Stable rolling technology of ultra-thin hot rolled strips such as 1.0 mm and 0.9 mm in thickness has been established, and the conventional minimum gauge of hot rolled strips (1.2 nn) has been lowered. The ultra-thin hot rolled strips have been provided to the market with a bland name 'RTHC' (river thin hot coil commercial grade) since 1997. The ultra-thin hot rolled strips have excellent quality in dimensional accuracy and mechanical properties. In addition, the ultra-thin hot rolled strips meet current needs of energy saving and reducing CO{sub 2}. New market and more demands for the newly developed product strips are expected. (author)

Yamada, N.; Kitahama, M.; Nikaido, H. [Kawasaki Steel Corp., Tokyo (Japan)

1999-09-01

183

Roll Call  

Science.gov (United States)

Roll Call is "The Newspaper of Capitol Hill since 1955", that covers the people, process and politics of Capitol Hill. The website has many multimedia features, including videos, an interactive timeline, podcasts, photo galleries, and political cartoons. Some of the sections of the online version of the paper include "News", "Opinion", "Politics", "Vested Interests", "Around the Hill", and "Investigations". To watch videos on various topics, or listen to Roll Call podcasts, visitors should click on "More Video", in the box entitled Roll Call Video, which resides in the middle of the page. The link provides recent videos, Roll Call on C-SPAN, Roll Call TV (CN8), podcasts, and a photo gallery of photos of the day. At the top of the homepage, visitors can find the latest news from Congress and the judiciary under the "Congress Now" tab. For policy intelligence on many issues, the "Briefing Room" tab allows visitors to explore the latest issues, divided into the topics of "Budget and Appropriations", "Defense", "Energy and Environment", "Foreign Policy and Trade", "Health", and "Homeland Security".

184

Utilization of radioactive tracers for modelling ore mills  

International Nuclear Information System (INIS)

Applications of radiotracer techniques to obtain residence time distribution functions of water and ore in primary mill (open-circuit) and secondary mill (close-circuit) are presented. Cr51 (EDTA) and irradiated ore were used as tracers. A kinetic model of grinding and the experimental methods to obtain kinetic parameters are described. Results obtained in industrial ball mill operating with feed of ore between 60 to 200 ton/hr are discussed. (Author)

1984-01-01

185

Method for grinding precision components  

Energy Technology Data Exchange (ETDEWEB)

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

186

THE MEANING OF “TOYOTARYZM” IN IMPROVING OF THE HOT-ROLLED PLATES PRODUCTION PROCESS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Steel mill and metal plants in Poland are struggling with a crisis in the global market. Option for metal plants in Poland may be methods of organizing production using methods of the Japanese production companies This chapter presents the concepts of "Toyotaryzm" and suggestions improvement of the mill hot-rolled plates by using asymmetric rolling process.

Szklarzyk, Pawe?; Klimecka-tatar, Dorota; Sygut, Piotr

2013-01-01

187

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

188

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)

1998-10-01

189

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2002-01-01

190

Transverse cylindrical grinding of a eutectic alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report herein on a comparison of the performance of two different grinding wheels (conventional and CBN) in the transverse cylindrical grinding of a eutectic alloy. Three cutting conditions were tested: rough, semi-finishing and finishing. The parameters of evaluation were the cutting force, roughness and wheel wear. The optimal cutting force and roughness values were obtained when grinding with the conventional wheel, due to the superior dressing operation performed under every cutting co...

2003-01-01

191

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 ...

2002-01-01

192

Internal Grinding of High-Speed Steels: Shorter Processing Times with Boron Nitride Grinding Tools.  

Science.gov (United States)

Boron nitride grinding tools can be used to advantage for the grinding of high speed steel (HSS) with a high vanadium content. the abrasives available to date are of limited value because the HSS materials contain very hard carbides, grinding of which, an...

D. Borse

1983-01-01

193

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

194

30 CFR 57.14115 - Stationary grinding machines.  

Science.gov (United States)

...2009-07-01 2009-07-01 false Stationary grinding machines. 57.14115 Section 57.14115...Maintenance Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders,...

2009-07-01

195

30 CFR 56.14115 - Stationary grinding machines.  

Science.gov (United States)

...2009-07-01 2009-07-01 false Stationary grinding machines. 56.14115 Section 56.14115...Maintenance Requirements § 56.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders,...

2009-07-01

196

30 CFR 75.1723 - Stationary grinding machines; protective devices.  

Science.gov (United States)

... 2009-07-01 false Stationary grinding machines; protective devices. 75...Miscellaneous § 75.1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit...

2009-07-01

197

30 CFR 77.401 - Stationary grinding machines; protective devices.  

Science.gov (United States)

... 2009-07-01 false Stationary grinding machines; protective devices. 77...Mechanical Equipment § 77.401 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit...

2009-07-01

198

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

199

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

200

'Diamond Jenness': A Tough Grind  

Science.gov (United States)

This microscopic imager mosaic of the target area called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time. Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer. On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed. The image mosaic is about 6 centimeters (2.4 inches) across.

2004-01-01

 
 
 
 
201

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...

2006-01-01

202

Precision grinding process development for brittle materials  

International Nuclear Information System (INIS)

High performance, brittle materials are the materials of choice for many of today's engineering applications. This paper describes three separate precision grinding processes developed at Lawrence Liver-more National Laboratory to machine precision ceramic components. Included in the discussion of the precision processes is a variety of grinding wheel dressing, truing and profiling techniques

1999-01-01

203

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

204

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

205

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.

2013-04-01

206

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

207

Surface Grinding Machine Stability Characteristics Limited Prediction  

Directory of Open Access Journals (Sweden)

Full Text Available The chatter in the grinding process has a great influence in improving work piece surface quality and production efficiency. The formula of flutter system limit grinding depth and the rotating speed of the grinding wheel are induced based on the chatter theory and the chatter dynamitic model of the grinding system. The computer modeling and simulation are carried out to get flutter stability predicted picture. Finally the reliability and validity of the predicted picture are verified by the experiments. Flutter stability prediction method provides a theoretical basis in selecting the grinding process parameters for the machine processing operators and it also has an important meaning to the work piece surface quality and processing efficiency.

Yuting Yang

2012-07-01

208

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

2003-07-01

209

Rolls-Royce implementing new production system  

Science.gov (United States)

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

1982-05-01

210

Mathematical modeling of deformation during hot rolling  

Energy Technology Data Exchange (ETDEWEB)

The deformation that occurs in the roll bite during the hot rolling of steel, particularly the strain-rate and strain distribution, has been mathematically modeled using finite-element analysis. In this paper three different finite-element models are compared with one another and with industrial measurements. The first model is an Eulerian analysis based on the flow formulation method, while the second utilizes an Updated Lagrangian approach. The third model is based on a commercially available program DEFORM which also utilizes a Lagrangian reference frame. Model predictions of strain and strain-rate distribution, particularly near the surface of the slab, are strongly influenced by the treatment of friction at the boundary and the magnitude of the friction coefficient or shear factor. Roll forces predicted by the model have been compared with industrial rolling loads from a seven-stand hot-strip mill.

Jin, D.; Stachowiak, R.G.; Samarasekera, I.V.; Brimacombe, J.K. [Univ. of British Columbia, Vancouver, British Columbia (Canada). Centre for Metallurgical Processing Engineering

1994-12-31

211

Measurement and analysis of forces in grinding of silicon nitride  

Energy Technology Data Exchange (ETDEWEB)

Using an instrumented surface grinder, the two components of grinding forces (normal and tangential) were measured for different types of silicon nitride ceramics. The influences of grinding parameters, such as down feed and table speed, and grinding fluids on forces were determined. In addition to these measurements, the specific grinding energy defined as the energy per unit volume of removed material was calculated. This parameter and the measured forces were then analyzed to determine possible correlations with mechanical properties of the silicon nitrides. It was found that, in general, the grinding forces and the specific grinding energy increase with the hardness. Both the grinding forces and the specific grinding energy were influenced by the grinding fluid and the grinding parameters. The implication of these results on the mechanisms of material removal in grinding of silicon nitride and the possible tribological effects are discussed.

Jahanmir, S.; Hwang, T.; Whitenton, E.P.; Job, L.S.; Evans, C.J. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1995-12-31

212

Thermal aspects of grinding for surface integrity  

Science.gov (United States)

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 area ratio, thermal properties, feeds and speeds, and type of cut (down or up grinding) on heat partition and workpiece temperature are studied systematically. It is shown that the presence of the fluid inside the grinding zone can reduce the heat flux into the workpiece and workpiece temperature significantly. It is also found that some ratios of workpiece velocity to wheel velocity result in high temperatures and therefore should be avoided. This result provides a basis for the difference between conventional and creep-feed grinding regions. After obtaining temperature, an efficient and robust FFT approach is developed to obtain the thermal stress field induced by moving heat sources. Study of the 'hot spot' problem shows that the effect of hot spots on surface displacement and stress is small suggesting that grinding thermal stress is induced by the global temperature while local temperature controls metallurgical phase transformations. It is also shown that thermal stress is dominant on the global scale while the global scale mechanical stress is insignificant. Thus, the superior thermal properties of CBN compared to Alsb2Osb3 leads to low temperature and less deleterious residual stresses. Finally, spectral analysis is performed to evaluate contact behavior of the finished surface. This analysis shows that a good grinding process improves not only the magnitude of the surface roughness but the frequency content as well.

Ju, Yongqing

213

Theoretical considerations of machining with grinding wheels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2013-01-01

214

Chatter in a transverse grinding process  

Science.gov (United States)

In transverse grinding, the wheel moves along the workpiece, which induces unique grinding dynamics. To understand these dynamic phenomena, specifically the grinding chatter, a new dynamical model of the process is proposed, in which the wheel position is assumed to be quasi-static since the transverse wheel velocity is small. From the stability and bifurcation analyses of the chatter vibration, it appears that the dynamics of the process is governed by the quasi-static interactions. Moreover, the obtained results also show that the wheel and workpiece chatters are quite different, having continuous and intermittent characters respectively.

Yan, Yao; Xu, Jian; Wiercigroch, Marian

2014-02-01

215

Milling effects on magnetic properties of melt spun Fe-Nb-B alloy  

Science.gov (United States)

Fe75Nb10B15 amorphous ribbons were grinded via ball milling to produce powder samples preserving the amorphous microstructure. A continuous increase of the Curie temperature with the milling time is observed as well as an enhancement of spontaneous magnetization, average hyperfine field, and magnetocaloric effect. This enhancement in the magnetic character of the samples as milling progresses is ascribed to an increase of the Fe-Fe distance. However, the peak entropy change reduces after grinding the ribbon sample. This effect could be related to a broader distribution of Curie temperatures in powdered samples.

Ipus, J. J.; Blázquez, J. S.; Franco, V.; Stoica, M.; Conde, A.

2014-05-01

216

Underground milling of uranium ores  

International Nuclear Information System (INIS)

Full text: This paper presents and analyzes the new concept of underground milling of high-grade uranium ore. Compared to conventional milling on surface, the underground milling scheme appears to offer significant cost savings and a lower environmental impact. The paper describes the underground milling scheme, presents process flowsheets and plant layouts, and provides an assessment of potential benefits from underground milling. In response to the current supply/demand situation for uranium, there has been, for the past few years, a 'uranium rush' in many parts of the world, including the resource-rich Athabasca basin situated in northern Saskatchewan. In a recent count, there were over forty uranium companies looking for uranium in this region. Positive results from any of these exploration activities could, depending on their location, potentially provide a source of additional feedstock for any of the existing milling centres in northern Saskatchewan and/or result in the establishment of additional new milling capacity. Underground milling would be considered in the latter instance. The above flowsheet shows the basics of the proposed underground milling scheme, which assumes the existence of a high-grade underground uranium mine, similar to the current McArthur River mine or the planned Cigar Lake mine. Grinding, leaching, solid/liquid separation and tailings deposition are all carried out underground. Leach liquor is pumped to surface for impurity removal, precipitation and drying. The impurities, removed as chemical precipitates, are moved back underground for disposal. Expected environmental benefits are significant and include reduction of surface visual impact, leach residues remain underground, and no tailings management facility on surface. Indeed the process residue is arguably more isolated from the environment than was the ore before mining. Contaminant transport from the stored tailings to surface waters is extremely slow. Application of membrane technology to water treatment for the underground milling scheme is expected to provide an aqueous effluent with minimal loading to the environment. In addition to these substantial environmental benefits, underground milling is expected to give a capital cost saving on the order of 35% and an operating cost saving on the order of 30% relative to conventional mining and milling. (author)

2009-06-22

217

Evaluation of Grinding Wheel Surface by Means of Grinding Sound Discrimination  

Science.gov (United States)

In this study, a new technique of in-process evaluation of a grinding wheel surface is proposed. Some specific wheel surfaces are prepared as references by the appropriate truing and/or dressing procedure, and grinding sounds generated by these wheels are discriminated by analyzing the dynamic frequency spectrum by a neural network technique. In the case of a conventional vitrified-bonded alumina wheel, the grinding sound can be identified in the optimum network configuration. Therefore, this system can instantaneously recognize differences in the wheel surface with a good degree of accuracy insofar as the wheel conditions are relatively widely changed. In addition, the network can perceive wheel wear because the grain tips are flattened as grinding proceeds and the grinding sound becomes similar to that of a wheel generated with lower dressing feed. The resinoid-bonded cubic boron nitride (CBN) wheel is also discriminable when a grinding sound in a higher frequency range is analyzed.

Hosokawa, Akira; Mashimo, Kazufumi; Yamada, Keiji; Ueda, Takashi

218

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

219

Automatic grinding apparatus to control uniform specimen thicknesses  

Science.gov (United States)

This invention is directed to a new and improved grinding apparatus comprising (1) a movable grinding surface, (2) a specimen holder, (3) a displacing device for moving the holder and/or grinding surface toward one another, and (4) at least three devices for limiting displacement of the holder to the grinding surface.

Bryner, Joseph S. (Pittsburgh, PA)

1982-01-01

220

Finishing of disk tools for rolling spiral fins on tubes  

Energy Technology Data Exchange (ETDEWEB)

At the All-Union Scientific-Research and Design Institute for Chemical and Petroleum Apparatus Building Technology, Volgograd, a special machine has been designed and built and investigations have been made to provide tool working surfaces with high quality. Finds that the increase in surface quality of the rolling tools as a result of abrasive grinding with a belt on the special machine makes it possible to reduce external friction in the rolling zone, as a result of which there is an improvement in the conditions of radial flow of the tube metal. Savings are obtained as a result of a decrease in the power required by the electric motors for rolling of finned tubes. This is an indication of a reduction in the forces of friction in the source of change in form of the fins and approximately doubles the life of the rolling tool. The production operation of grinding the parts of the rolling tool with an abrasive belt and a special machine has been introduced into the Lauristin Tallin Machine Building Plant.

Sultanov, T.A.; Buneev, B.G.; Yurova, T.I.

1982-09-01

 
 
 
 
221

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2002-01-01

222

Evolution of artificial defects during shape rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Very often defects are present in rolled products. For wire rods, defects are very deleterious since the wire rods are generally used directly in various applications. For this reason, the market nowadays requires wire rods to be completely defect-free. Any wire with defects must be rejected as scrap which is very costly for the production mill. Thus, it is very important to study the formation and evolution of defects during wire rod rolling in order to better understand and minimize the pro...

2007-01-01

223

Practice of Improving Roll Deformation Theory in Strip Rolling Process Based on Boundary Integral Equation Method  

Science.gov (United States)

Precise strip-shape control theory is significant to improve rolled strip quality, and roll flattening theory is a primary part of the strip-shape theory. To improve the accuracy of roll flattening calculation based on semi-infinite body model, a new and more accurate roll flattening model is proposed in this paper, which is derived based on boundary integral equation method. The displacement fields of the finite length semi-infinite body on left and right sides are simulated by using finite element method (FEM) and displacement decay functions on left and right sides are established. Based on the new roll flattening model, a new 4Hi mill deformation model is established and verified by FEM. The new model is compared with Foppl formula and semi-infinite body model in different strip width, roll shifting value and bending force. The results show that the pressure and flattening between rolls calculated by the new model are more precise than other two models, especially near the two roll barrel edges.

Yuan, Zhengwen; Xiao, Hong; Xie, Hongbiao

2014-02-01

224

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.

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

225

Low specific-grinding energy machining of ceramics by a laser dressed diamond grinding stone  

International Nuclear Information System (INIS)

A laser dressing is an effective dressing method to accomplish efficient ceramic grinding. Since laser dressing achieves protrusion heights of abrasive-grains without grain dislodgment, the number of abrasive-grains in a laser dressed grinding stone (LGS) is higher than that in a mechanically dressed grinding stone (MGS), remaining the initial grain distribution. Thus, the LGS contains higher number of effective cutting edges, and forms higher number of ground grooves on a ground surface than the MGS. Consequently, the LGS can achieve lower specific grinding energy than the MGS. Copyright (2003) AD-TECH - International Foundation for the Advancement of Technology Ltd

2003-01-01

226

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.

Fusse Ronaldo Yoshinobu

2004-01-01

227

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 in...

2004-01-01

228

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)

1974-01-01

229

Burn threshold prediction for high efficiency deep grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Burn threshold diagrams are useful for the prediction of thermally induced grinding damage and were originally developed to describe the conventional shallow cut grinding regime. With the development of new high stock removal grinding processes such as High Efficiency Deep Grinding (HEDG), the prevention of thermal damage to the workpiece is of particular concern. The principle of HEDG is based around the change in thermal characteristics of the grinding process at high Peclet numbers, whereb...

2006-01-01

230

Heat distribution when nickel alloy grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Heat distribution in machining is one of the phenomenological characteristics of this process because it significantly influences functional properties of machined surfaces. This paper deals with heat distribution during grinding of Ni alloy and its relationship to the quality of ground parts in terms of residual stresses. The analysis of the heat distribution is based on measurement of the temperature in the contact of the grinding wheel and the workpiece, and the tangential component of cut...

Neslus?an, Miroslav; Mrkvica, Ivan; C?ep, Robert; Raos, Pero

2012-01-01

231

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

232

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

233

Research on the processing speed of cam grinding  

Science.gov (United States)

Cam Grinding is a special kind of non-circular machining. The processing speed of cam grinding has a major influence on cam machining precision. In this paper, decomposed the X-axis feed speed and C-axis velocity by the tangential speed and normal speed in accordance with the curvature circle at the point of cam profile grinding. Proposed the cam grinding processing speed model and linear velocity calculation formula, the processing experiment on the CNC camshaft grinding machine results show that the cam grinding speed model is correct. Constant angular speed grinding and constant linear speed grinding are analyzed respectively, which provides a theoretical basis for cam grinding processing speed optimization.

Peng, Baoying; Han, Qiushi

2010-12-01

234

Mill machines  

Energy Technology Data Exchange (ETDEWEB)

The paper looks at the application of hammer mills for lignite fragmentation. The Aubema hammer mill is being tested at a pilot drying plant in Germany. It has a rotor diameter of 2m and rotor width of 2.5 m. A second will can be connected in series to reduce grain size down to below 1 mm. 2 photos.

Goetz, B. [Aubema Maschinenfabrik GmbH (Germany)

2003-08-01

235

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

236

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1996-01-01

237

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

238

Cryogenic grinding: an efficient method for recycling scrap rubber  

Energy Technology Data Exchange (ETDEWEB)

Cryogenic grinding represents an opportunity for expanding recycling capabilities to a broad range of compounds. Many materials that can be reduced to a powder by conventional coarse grinding can be reduced more efficiently by using a super-cold agent such as liquid nitrogen at -320/sup 0/F to embrittle plastic or rubber polymers before grinding. In addition, cryogenic grinding makes possible the size reduction of many materials that cannot be ground by conventional ambient grinding methods. Some experiences of cryogenic grinding in practice at United Tire and Rubber company, Limited, headquartered in Rexdale, Ontario, are noted. A schematic of such a system is shown.

1980-06-01

239

Transverse cylindrical grinding of a eutectic alloy  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english We report herein on a comparison of the performance of two different grinding wheels (conventional and CBN) in the transverse cylindrical grinding of a eutectic alloy. Three cutting conditions were tested: rough, semi-finishing and finishing. The parameters of evaluation were the cutting force, roug [...] hness and wheel wear. The optimal cutting force and roughness values were obtained when grinding with the conventional wheel, due to the superior dressing operation performed under every cutting condition tested. Although the CBN wheel presented the best G ratio values, they were lower than expected owing to the inappropriate dressing operation applied. Excessive wheel corner wear was detected in both wheels, caused by the grinding kinematics (transverse grinding) employed. In terms of cutting force and roughness, the conventional wheel proved to be the better choice under the conditions tested. However, in terms of the G ratio, a cost analysis is crucial to determine whether the differences between the wheels justify the use of the CBN wheel, in which case the dressing operation requires improvement.

Bianchi, E. C.; Vargas, V. L.; Magagnin, T. C.; Monici, R. D.; Vicari Filho, O.; Aguiar, P. R. de; Silva, E. Jannone da.

240

Transverse cylindrical grinding of a eutectic alloy  

Directory of Open Access Journals (Sweden)

Full Text Available We report herein on a comparison of the performance of two different grinding wheels (conventional and CBN in the transverse cylindrical grinding of a eutectic alloy. Three cutting conditions were tested: rough, semi-finishing and finishing. The parameters of evaluation were the cutting force, roughness and wheel wear. The optimal cutting force and roughness values were obtained when grinding with the conventional wheel, due to the superior dressing operation performed under every cutting condition tested. Although the CBN wheel presented the best G ratio values, they were lower than expected owing to the inappropriate dressing operation applied. Excessive wheel corner wear was detected in both wheels, caused by the grinding kinematics (transverse grinding employed. In terms of cutting force and roughness, the conventional wheel proved to be the better choice under the conditions tested. However, in terms of the G ratio, a cost analysis is crucial to determine whether the differences between the wheels justify the use of the CBN wheel, in which case the dressing operation requires improvement.

E. C. Bianchi

2003-03-01

 
 
 
 
241

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 R

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

2011-01-01

242

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

International Nuclear Information System (INIS)

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

2007-04-07

243

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

Science.gov (United States)

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

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

2007-12-26

244

A method for selective grinding of coal  

Energy Technology Data Exchange (ETDEWEB)

The method of selective grinding of coal is patented here and is based on the fact that coal is subjected to the effect of low molecular organic liquids or their vapors, and afterwards, it is selectively ground and separated into specific classes. In order to improve the interaction of low molecular organic liquids from the surface of the coal, they are subjected to pressure directly on the surface of the coal or after the preliminary elimination of air from it. Such a processing of the surface of the coal before its grinding makes it possible to produce a separate kernel fraction with low contents of slime, concentrated in petrographic difference, such as vitrinite, exinite, applied in industrial shops. In the testing of a coal specimen, containing 60% vitrinite and 12% exitite, after a two hour processing with methanol, grinding, and classification, 90% of the virtrinite and exinite was produced in the kernel fraction of 5 to 0.2 millimeters.

Blaszczynski, S.; Nawrocki, J.; Olas, A.; Steinhoff, J.

1980-11-29

245

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Yousaf, Naeem

2009-01-01

246

Amorphization of NiZr{sub 2} under ball-milling: validation of the milling intensity  

Energy Technology Data Exchange (ETDEWEB)

Studies of amorphization of NiZr{sub 2} compound have been carried out in a magneto ball-mill capable to operate in two milling mode, depending of the direction of the applied magnetic field. The first mode favours ball impacts and the second one cold rolling. We show that much in the same way as in a vertical frame grinder, the compound reaches a two phase (amorphous plus crystalline) steady structure and that the volume fraction of amorphous phase depends at given milling temperature on the milling intensity. The milling intensity is as defined by Chen, the momentum transferred per unit mass of powder per unit time : the higher the milling intensity, the higher the fraction of amorphous phase. However the intensity required to reach a given fraction of amorphous phase in the magneto ball-mill seems to be much lower than in the vertical frame grinder. The rolling mode is found to be more efficient than the impact mode at equivalent milling temperature for promoting amorphization. (orig.)

Chaffron, L. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Section de Recherches de Metallurgie Physique; Poissonnet, S. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Section de Recherches de Metallurgie Physique

1996-12-31

247

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

International Nuclear Information System (INIS)

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

1996-01-01

248

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

249

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.

250

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

2013-01-01

251

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

252

A contribution to scale growth during hot rolling of steel  

Energy Technology Data Exchange (ETDEWEB)

This work was carried out in context with the development of strip casting by the single-belt process. In this new process the casting is directly connected with hot rolling which must be carried out at lower speed than in conventional hot rolling, to match the casting rate. It is of interest to theoretically study the effect of low rolling speed on operational parameters and materials behaviour, among them scale formation. In the present investigation it is demonstrated that, under the conditions of hot rolling, the oxidation of iron in air is governed by a mixed mechanism involving diffusion in the oxide and transport of molecular oxygen in the gaseous boundary layer. An algorithm has been formulated for the description of the deformation behaviour of the scale in the roll bite. Scale formation was computed for conventional finishing rolling with a seven stand mill and for in-line hot rolling of strip produced by the single-belt process. It is found that the final scale thickness in the single-belt casting/in-line hot rolling process is about twice that in conventional hot rolling, for the same strip thickness behind the last stand. (orig.)

Schwerdtfeger, K.; Zhou, S. [Inst. fuer Metallurgie, Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany)

2003-09-01

253

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2008-01-01

254

Development of an 'intelligent grinding wheel' for in-process monitoring of ceramic grinding. Semi-annual report no. 1.  

Science.gov (United States)

The overall objective of this project is to develop sensor-integrated 'intelligent' diamond wheels for grinding of ceramics. Such wheels will be 'smart' enough to monitor and supervise both the wheel preparation and grinding processes without the need to ...

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

1997-01-01

255

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

256

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

257

Physicochemical and grinding characteristics of dragonhead seeds  

Science.gov (United States)

The results of investigations on the physicochemical and grinding characteristics of Moldavian dragonhead seeds are presented. The data obtained showed that the physical properties (average size, sphericity, surface area, 1 000 seed mass, dynamic angle of repose, coefficient of static friction, and bulk and true densities) of the white and blue form of dragonhead seeds were not significantly different. Both forms of dragonhead showed similar levels of protein (average of 21%), whereas the blue form of dragonhead had a lower fat content (average of 23.1%) and higher mucilage content (13.35%) in comparison to the blue form of seed (24.6 and 9.95%, respectively). Antioxidant capacity of dragonhead seeds was comparable for both forms and averaged about 40%, which corresponded to EC50 values of 0.12 and 0.13 mgml-1 for the white and blue forms, respectively. The grinding material showed similar particle size distribution of ground material for both forms of dragonhead seeds. The lowest values of specific grinding energy were obtained for the white form of dragonhead seeds, those for the blue form were significantly higher. Grinding of dragonhead seeds using a screen 2.0 mm mesh size caused screen hole clogging. This problem did not occur when dragonhead seeds were mixed with wheat grain.

Dziki, D.; Mi?, A.; G?adyszewska, B.; Laskowski, J.; Kwiatkowski, S.; Gawlik-Dziki, U.

2013-12-01

258

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

259

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...

2006-01-01

260

Test research on sticking mechanism during hot rolling of SUS 430 ferritic stainless steel  

Science.gov (United States)

The sticking phenomenon during hot rolling of SUS 430 ferritic stainless steel was investigated by means of a two-disc type high-temperature wear tester. The test results indicate that sticking particles on the surfaces of high chromium steel (HiCr) and high-speed steel (HSS) rolls undergo nucleation, growth, and saturation stages. Grooves on the roll surface generated by grinding provide nucleation sites for sticking particles. The number of sticking particles on the HiCr roll surface is greater than that on the HSS roll surface. The average surface roughnesses ( R a) of HiCr and HSS rolls change from 0.502 and 0.493 ?m at the initial stage to 0.837 and 0.530 ?m at the saturation stage, respectively. The test further proves that the sticking behavior is strongly dependent on roll materials, and the HSS roll is more beneficial to prevent particles sticking compared with the HiCr roll under the same hot-rolling conditions.

Liu, Jun-Xian; Zhang, Yong-Jun; Han, Jing-Tao

2010-10-01

 
 
 
 
261

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.

262

Power and operating behavior in stirred media mills  

Energy Technology Data Exchange (ETDEWEB)

It has been estimated that 1.3% of Us electrical power production is consumed for comminution, particularly by fine grinding. Stirred media mills have especially attracted attention because of the reported high energy efficiency, ability for grinding into the micron and sub-micron range, and reduced contamination. Stirred media mills have been applied for fine particle production in many industries such as mineral, ceramic, metallurgical, electronic, pigments, paint and lacquer, chemical, bio-technology, rubber, agricultural, pharmaceutical, photographic, coal and energy. While applications of stirred media mills for fine particle production have continued to increase, there is a lack of understanding of operating behavior and power requirement. Investigations in laboratory stirred media mills have been carried out with grinding media, limestone and yttria stabilized zirconia. The torque required to rotate impellers immersed in dense particulate media with supernatant versus impeller rotational speed displays four regions marked by sharp transitions: transition from static to dynamic friction; channeling; dispersing; and centrifuging. Equations, including dimensionless group correlations of power and modified Reynolds number, for relating power, speed, impeller and tank dimensions and design, media size and density, solid concentration, and other relevant variables have been established. Scale-up guidelines with respect to power consumption are also proposed.

Zheng, J.; Harris, C.C. [Columbia Univ., New York, NY (United States). Henry Krumb School of Mines

1995-12-31

263

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.

Jørgensen, John Bagterp

2012-01-01

264

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

265

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-07-01

266

Effect of grinding on photostimuable phosphors for x-ray screens  

International Nuclear Information System (INIS)

Luminescence efficiency of a phosphor can be improved by minimizing the energy losses during excitation. The loss of excitation energy in the case of powdered samples is mainly due to scattering of incident radiation by the particles of phosphor. Thus, while considering the industrial applications of polycrystalline phosphors in lamps, screens, paints, etc., the effect of particle size on the light output has to be specially studied. It is very well established that the radiographic imaging with photostimuable (PS) phosphors has many advantages over conventional photographic film screens. In the new type of computer radiography, PS phosphors are to be used as memory materials for temporary storage of the x-ray image. Eu(2+) doped barium fluorohalide phosphors are most suitable for this purpose. The spatial resolution from the image plate can be improved to a certain extent with phosphors comprising fine particles. The fineness of the particles can be achieved by various means such as grinding, fast cooling after firing or incorporation of some flux materials during the firing processes. But the efficiency of the phosphor deteriorates with grinding. Fast cooling is a complicated process in the case of Eu(2+) doped phosphors. Incorporation of flux materials may change the characteristics of phosphor materials. In the present investigation, effect of grinding (ball milling) on particle size distribution, shape of the particles and luminescent properties of BaFCl phosphors have been studied

1988-10-09

267

Production of talc nano sheets via fine grinding and sonication processes  

International Nuclear Information System (INIS)

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

2009-01-01

268

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-05-15

269

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.

2011-05-01

270

Converting the Key Lake mill process for McArthur River ore  

Energy Technology Data Exchange (ETDEWEB)

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)

Rodgers, C. [McArthur River Operation, Cameco Corporation, Saskatoon, Saskatchewan (Canada)

2000-07-01

271

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)

2000-09-09

272

Evaluation on some important force models for cold strip rolling  

Energy Technology Data Exchange (ETDEWEB)

To improve the accuracy of rolling force prediction, some important force models were evaluated through applied computation for cold rolling of low carbon steel and aluminum alloy according to measured data on lab mill. The effects of model structure and three important variables - flow stress, contact length and friction coefficient - on the precision of computed force were quantitatively studied. Flow stress was measured with plane-strain compression test, contact length was based on elastic flattening of work-roll by Hitchcock, and friction-coefficient was determined by rolling strain and numerical iteration. In steel rolling Bland and Ford integration model and Bryant and Osborn algebraic equation are better in accuracy than Ekelund and Parkins. In aluminum rolling all the models produce large deviations {delta}F{sub R} = 10-20% if flow stress, contact length and friction coefficient are determined with the same method as steel rolling. The elastic deformation of aluminum strip is now taken into account for its low elastic modulus. An effective method to determine plastic and elastic contact has been developed in this investigation. The accuracy of force computation is obviously improved for aluminum rolling. (orig.)

Li Guangying; Lagergren, J. [Royal Inst. of Tech. (KTH), Stockholm (Sweden). Dept. of Material Processing

2000-11-01

273

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

274

Process for grinding geologically young peat, lignine, soft brown coal and energetic coals, as well as preparing them for pulverized-coal combustion  

Energy Technology Data Exchange (ETDEWEB)

A process for grinding and drying geologically young peat, lignine, soft brown coal and energetic brown coals, and preparing them for pulverized-coal combustion, wherein raw fuel and a drying and carrier gas are led into a ventilator-mill operated at high speed, and wherein in the ventilator-mill the fuel is pre-comminuted and dried, the coarse fraction is led out from a classifier, e.g. an air-separator, and ground to the desired fineness in a roller mill, the grist leaving the roller mill is recycled to the ventilator mill and from there the final fine fraction ready to be combusted is passed to the place of application, e.g. burners.

Bodi, B.; Gruber, K.; Iring, R.; Markovics, J.; Nagy, L.; Pal, S.; Ruttkay, Z.

1990-06-06

275

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

276

Grinding steel and iron materials with Cu-Sn-Co bonded CBN grinding wheels  

Energy Technology Data Exchange (ETDEWEB)

CBN(Cubic Boron Nitride) unlikely to diamond has a slightest chemical wear on grinding iron family materials. This merit brings CBN grinding wheel to widely use referring to grinding iron and steel parts. however, the performance of CBN grinding wheels depends on bonding materials which are bonded to CBN abrasives. Out of widely used bonding materials today, tin bronze alloy has limit to wear resistance. In order to increase the wear resistance of tin bronze, Co is added in matrix of which composition results in Cu-Sn-Co. In addition to this matrix, Co coated CBN abrasive are used to increase the wettability with metal components. When 20 wt% Co is added on tin bronze matrix, the effect of self dressing becomes active the increasing the brittleness. Because {delta}Phase having the brittleness was formed between Co and tin bronze of {alpha}phase. The highest grinding ration is shown when Cu-15 wt%Sn, Cu-33 wt%Sn and Co are mixed with ratio of 40:40:20. (author). 12 refs., 13 figs. 1 tab.

Choi, Sung Kook; Choe, Jeong Cheol [Ajou University, Suwon (Korea, Republic of)

1995-06-01

277

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)

2005-07-01

278

Adaptive Automatic Gauge Control of a Cold Strip Rolling Process  

Directory of Open Access Journals (Sweden)

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

ROMAN, N.

2010-02-01

279

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)

1962-01-01

280

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...

2008-01-01

 
 
 
 
281

Improvement of hydrogen-storage properties of Mg by reactive mechanical grinding with Fe2O3  

International Nuclear Information System (INIS)

We tried to improve the H2-sorption properties of Mg by mechanical grinding under H2 (reactive mechanical grinding) with Fe2O3 under various milling conditions. The sample Mg-10 wt.%Fe2O3 prepared by milling at a revolution speed of 250 rpm for 24 h has the best hydrogen-storage properties. It absorbs 5.05 wt.% hydrogen at 593 K under 12 bar H2 for 60 min at the first cycle. Its activation is accomplished after three hydriding-dehydriding cycles. The activated sample absorbs 4.22 wt.% hydrogen at 593 K, 12 bar H2 for 10 min. The reactive grinding of Mg with Fe2O3 increases the H2-sorption rates by facilitating nucleation (by creating defects on the surface of the Mg particles and by the additive), by making cracks on the surface of Mg particles and reducing the particle size of Mg and thus by shortening the diffusion distances of hydrogen atoms. Hydriding-dehydriding cycling also increases the H2-sorption rates by creating defects on the surface of the Mg particles, and by making cracks on the surface of Mg particles and reducing the particle size of Mg

2005-06-21

282

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

283

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

Directory of Open Access Journals (Sweden)

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

M. Drobne

2014-10-01

284

Remote-controlled grinding robot system for repair work  

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-07-01

285

Remote-controlled grinding robot system for repair work  

International Nuclear Information System (INIS)

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

1991-01-01

286

In-Orbit Construction with a Helical Seam Pipe Mill  

Science.gov (United States)

The challenges of building large structures in space, and in particular a torus habitat, require novel processes. One potential method is to manufacture helical seam (also called spiral) pipe in orbit using a pipe mill. These machines turn rolls of steel or alloy into fully formed, welded and inspected pipe, pressure vessels and silos of various diameters. Pipe mills are highly automated and efficient in a factory environment and are increasingly being used for in-situ repair. By constructing in-orbit (on-orbit assembly) the launch vehicle can supply full payloads of compact, robust rolls of material; and the installation design is less restricted by fairing constraints and modular limitations. The use of a pipe mill is discussed as a possible construction method, for comparison an example design envelope is shown and further pipe mill products are considered.

Gilhooley, N.

287

Wear of grinding wheels - software for their selection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An existing model of the grinding process has been upgraded to predict grinding wheel wear as G ratios. It has been successfully benchmarked against experimental results for several combinations of coolant wheel and workpiece. As a Windows-based application, it offers a rapid and versatile way of assessing the performance of grinding wheels and processes in a realistic way. For the best results, it should be benchmarked before use against appropriate experimental results.

Torrance, Archibald Andrew

2004-01-01

288

CALCULATION OF SURFACE ROUGHNESS PARAMETERS FOR EXTERNAL CYLINDRICAL GRINDING  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Vladimir BOGUTSKY

2013-05-01

289

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. ...

Hegeman, Johannes Bernardus Jan-willem

2000-01-01

290

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.

2013-01-01

291

Milling of Si3N4 with Si3N4 Hardware.  

Science.gov (United States)

The grinding of Si3N4 powder using reaction bonded Si3N4 attrition, vibratory, and ball mills with Si3N4 media was examined. The rate of particle size reduction and the change in the chemical composition of the powder were determined in order to compare t...

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

1984-01-01

292

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

International Nuclear Information System (INIS)

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

2013-02-01

293

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-02-15

294

Monte Carlo simulation of particle breakage process during grinding  

Energy Technology Data Exchange (ETDEWEB)

The Monte Carlo method is quite useful in the modeling of particulate systems. It is used here to simulate the particle brekage process during grinding that can be represented by a population balance equation. The simulation technique is free from discretization of time or size. The results of simulation under restricted conditions of grinding compare very well with the available analytical solution of the population balance equation. The procedure is extended to simulate the grinding process in its entirety. This method provides an alternative to the modeling of the grinding process where the governing population balance equation cannot be readily solved. copyright 2000 Elsevier Science S.A. All rights reserved. (orig.)

Mishra, B.K. [Dept. of Materials and Metallurgical Engineering, Indian Inst. of Tech., Kanpur (India)

2000-06-12

295

Recordkeeping practices of beef grinding activities at retail establishments.  

Science.gov (United States)

Ground beef has been implicated as a transmission vehicle in foodborne outbreaks of infection with pathogens such as Escherichia coli O157:H7 and Salmonella. During outbreak investigations, traceback of contaminated beef to the producing facility is often unsuccessful because of inadequate recordkeeping at retail establishments that grind beef products. We conducted a survey in three states participating in the Environmental Health Specialists Network to describe beef grinding and recordkeeping practices at retail establishments. In each establishment that maintained grinding logs, three randomly selected records were reviewed to determine whether important data elements for traceback investigations were recorded. One hundred twenty-five stores were surveyed, of which 60 (49%) kept grinding logs, including 54 (74%) of 73 chain stores and 6 (12%) of 51 independent stores. One hundred seventy-six grinding records from 61 stores were reviewed. Seventy-three percent of the records included the establishment code of the source beef, 72% included the grind date and time, and 59% included the lot number of the source beef. Seventy-five percent of records noted whether trimmings were included in grinds, and 57% documented cleanup activities. Only 39 (22%) records had all of these variables completed. Of stores that did not keep grinding logs, 40% were unaware of their purpose. To facilitate effective and efficient traceback investigations by regulatory agencies, retail establishments should maintain records more detailed and complete of all grinding activities. PMID:21669085

Gould, L Hannah; Seys, Scott; Everstine, Karen; Norton, Dawn; Ripley, Danny; Reimann, David; Dreyfuss, Moshe; Chen, Wu San; Selman, Carol A

2011-06-01

296

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...

2004-01-01

297

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

298

Development of grinding robot. Kensaku robotto no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

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

Tazaki, Taketoshi; Yokoo, Takashi

1989-12-01

299

Observations on the grinding of alumina with variations in belt speed, load, sample rotation, and grinding fluids  

Energy Technology Data Exchange (ETDEWEB)

The volume of material removed in the grinding of alumina on a diamond-impregnated grinding belt was studied. Four grinding process parameters were tested: belt speed, normal load at the pin's contact surface, sample rotation during grinding, and grinding fluid. The results showed that at low loads the belts speed did not have a significant effect on material removal rates; however, the material removal rate decreased at higher loads combined with higher speeds. It decreased, in particular, when the sample was also rotated. Of the fluids used, the 50% ethylene glycol--50% water mixture produced the highest material removal rates while the lowest were produced by biodegradable soybean oil. The test conditions that produced high temperatures at the contact surface contributed to plowing as opposed to cutting and resulted in reduced material removal rates. The reasons for these variations were investigated by scanning electron microscopy of the surfaces, which revealed evidence of plastic deformation and temperature rise during grinding.

Schwartz, C.J.; Bahadur, S.

1998-07-01

300

CISM Course on Rolling Contact Phenomena  

CERN Document Server

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

Kalker, Joost

2000-01-01

 
 
 
 
301

Study of flow through a bowl mill model  

Energy Technology Data Exchange (ETDEWEB)

Bowl Mills are used in Thermal Power plants for pulverizing the raw coal, while drying, to the required fineness and achieve the desired combustion efficiency in the boiler. The Indian coals contain high ash content (some times as high as 60%) and as such the primary air has to handle media of different density namely the coal and the quartz. In this context, the distribution of air in the mill plays a significant role in the lifting of particles from the mill. The wear on the rotating components is increased through repetitive grinding because of improper distribution of air within the mill. Reduction of wear and enhancement of life of mill internals including the rotating components is a continuing goal and few more studies have been carried out in this direction. One such study is the replacement of rotating vane wheel and deflector in the separator body with an air guide ring and air diversion plate. Model studies have been carried out by traversing a five hole prove at different locations within the mill to study the distribution of flow as a result of this modification. The variation of absolute velocity and the associated flow direction has been calculated to describe the flow structure within the mill. The results are presented in non dimensional form to draw suitable conclusions. The present study indicated the possibility of improvement in the distribution of flow within the mill with increased magnitude of velocity at different locations.

Murty, G.V.R.; Babu, U.S.

1998-07-01

302

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.

303

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.

304

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.

305

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

Science.gov (United States)

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

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

2011-09-30

306

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

307

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

308

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

Science.gov (United States)

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 equip...

J. A. Kovach S. Malkin

1995-01-01

309

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

310

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

311

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

312

Conformational polymorphism on imatinib mesylate: grinding effects.  

Science.gov (United States)

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

Grillo, Damián; Polla, Griselda; Vega, Daniel

2012-02-01

313

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 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)

2007-01-01

314

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

315

Corrosion behavior of steel plates with mill scale. Mill scale fuchaku kohan no fushoku kyodo  

Energy Technology Data Exchange (ETDEWEB)

The corrosion behavior of hot rolled steel plates with mill scale for ships was examined by immersion tests and intermittent immersion tests in sea water and tap water. In the immersion tests and intermittent immersion tests in tap water, severe pitting corrosion was found on specimens with mill scale in descending order of 40 {degree} C sea water, ordinary temperature sea water and 40 {degree} C tap water, however, the deepest pit was found in the immersion test in tap water. In the intermittent immersion tests in sea water, deeper pits were found on machined specimens than on mill scaled ones. The severest corrosion was also found on the bare specimen coupled with a mill scaled one where the area ratio of bare one to mill scaled one was 1:630. Such complicated corrosion behavior was conceivable to be caused by the interaction among the acceleration of corrosion with mill scale, the anode area increased by removal of mill scale, and the growth and reduction of corrosion products. 9 refs., 6 figs., 3 tabs.

Zama, M.; Ueda, K.; Mori, T. (Mitsubishi Heavy Industries, Ltd., Tokyo, (Japan))

1990-03-15

316

Thermal modeling of grinding for process optimization and durability improvements  

Science.gov (United States)

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

Hanna, Ihab M.

317

Managing and recycling hydraulic and process oils at a cold mill  

Energy Technology Data Exchange (ETDEWEB)

Stelco has a plan in place to reduce environmental liability and cost at its Hilton Works Cold Rolling Mill. The plan emphasizes a multilevel team approach in order to achieve success in four major areas. The development of an alkali recycling process was the first breakthrough accomplished under the plan. Subsequent work produced an innovative method of treating solutions used in cold rolling which promises to extend rolling solution life. The work has since produced a proprietary method of recycling hydraulic fluids from mill sumps to be reused as prime product. Experimentation is underway to develop recycling methods for other mineral- and animal fat-based oils. This paper reviews the company`s program, particularly the rejuvenation of hydraulic and other waste fluids that are by-products of steel plant cold rolling mills. The management of the collection process and the economics of the recycling technology will be described.

Bowering, R.E.; Davis, C.T. [Stelco Hilton Works, Hamilton, Ontario (Canada); Braniff, D.P. [Forsythe Lubrication Associates Ltd., Hamilton, Ontario (Canada)

1997-07-01

318

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

Science.gov (United States)

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

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

2006-04-01

319

Innovative technologies for improved management of chemicals and oils at Stelco`s Hilton Works cold mill  

Energy Technology Data Exchange (ETDEWEB)

Stelco`s Hilton Works has in place a 3-year plan to reduce environmental liability and cost at its cold mill. A blueprint of all liquid wastes generated in the cold mill identified alkali cleaners as a prime candidate for recycling. A novel alkali recycling process has been developed and is now operating at two cleaning lines. Similarly, a proprietary method of recycling hydraulic oils from mill pits for reuse as prime product has been developed. Further studies are under way to recycle tandem rolling mill detergents. Innovative technologies are also being applied to the removal of particulates (irons, wood chips and mill dirt) from tandem mill rolling solutions and detergents. These processes show promise of being much less expensive than current technologies. The philosophy and economics behind the cold mill environmental improvement plan and the successes achieved so far will be reviewed.

Bowering, R.E.; Dowdy, R.C.; Heikoop, M.W.; Roeder, G.A. [Stelco Inc., Hamilton, Ontario (Canada). Hilton Works

1995-07-01

320

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

 
 
 
 
321

An operational fluid for grinding optical lenses  

Energy Technology Data Exchange (ETDEWEB)

An operational fluid (Rzh) is proposed, which is used for polishing lenses. The operational fluid is an aqueous solution of at least one of the following compounds: sodium alginate, KMTs sodium, soidum polyacrylate, salt of polyacrylamide, SPL of maleic acid, hydrochloric acid of polythiourea, polyvinylbenzoltrimethylammonium chloride, hydrochloric salt of polyvinylpyridine, starch, polyacrylamide or polyoxyethylene. These substance are used in a volume of 0.5 to 100 grams per liter of water. During grinding and sharpening of lenses on a diamond disk in order to mount them in a frame, the operational fluid is atomized, preventing overheating and removal from the surface (Pv) of the lens the waste glass dust. When a lens of synthetic resin is being sharpened, then the operational fluid prevents foam formation and the waste, dust like resin is easily settled. The operational fluid is easily removed from the waste glass or synthetic resin and may be used over for processing lenses.

Koide, S.; Fukudzava, Y.; Nodzava, Y.

1982-06-18

322

A Robust Roll Damping Controller  

DEFF Research Database (Denmark)

The effectiveness of rudder roll damping is sensitive to ship dynamic parameters. A recent model of a containership in waves include a nonlinear model and wave response operators. The vessel is sensitive in roll and has a low metacentric height, with a long natural roll period of 25 s. It was therefore interesting to investigate whether rudder roll damping was feasible. In this paper an Hâ?? controller is designed to optimise rudder roll damping. Steering and roll damping are hierarchical loops. Sea-way simulation results show that a successful controller design can be made

Yang, Chengen; Blanke, Mogens

1999-01-01

323

Multi-scale modelling of hot rolled dual-phase steels for process design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis investigates and models the austenite to ferrite transformation in the hot rolling of two different dual phase steels. The investigation has been carried out in a deformation dilatometer as well as a 4-stand pilot rolling mill. Three different modelling approaches were employed to give different aspects of information and for different applications. Macroscopic kinetics model base on JMAK rate form gives simple overall kinetics information and indicates the appropriate process win...

Suwanpinij, Piyada

2012-01-01

324

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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 c [...] utting 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; Silva, Eraldo Jannone da; Vargas, Vinicio Lucas; Magagnin, Thiago Cardoso; Monici, Rodrigo Daun; Vicari Filho, Osmar; Aguiar, Paulo Roberto de.

325

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

326

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 diculties 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 dierent 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

327

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

328

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.

2013-04-01

329

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 agglomeration of particles.

2010-02-15

330

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

2007-07-01

331

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 School of Engineering,, The University of Newcastle

2010-01-01

332

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

333

Uranium milling operations at McClean Lake  

Energy Technology Data Exchange (ETDEWEB)

The McClean Lake mill commenced operations in June 1999, with a design production capacity of 6 million pounds of U{sub 3}O{sub 8} 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)

Badea, A.L.; Schwartz, L. [COGEMA Resources Inc., Saskatoon, Saskatchewan (Canada)

2000-07-01

334

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)

2000-09-09

335

Development of hot-rolled steel sheet with a high r-value by rolling in ferrite region with lubrication; Onkan junkatsu atsuen ni yoru ko r chi netsuen koban no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

For hot rolling with lubrication-annealing process possible to eliminate cold rolling process, study was made on the effect of lubrication characteristics on high r-value hot-rolled steel sheets. For production of hot-rolled steel sheets with a specially high r-value equivalent to cold- rolled steel sheets, lubrication in {alpha} region (ferrite) rolling, control of shear aggregate texture formed in steel sheet surface layers, and large reduction of solute carbon during pre-process of rolling are important. The r-value of nearly 1.5 was obtained by hot rolling with lubrication below 5% in forward slip rate using 1% synthetic ester emulsion as lubricant in a laboratory. For realizing these conditions, solution of the following issues is indispensable: development of a lubricant possible to achieve a high lubrication performance in real continuous hot rolling mills, establishment of rolling technology using such a lubricant, and development of a component design method and process for controlling and reducing solute carbon in {alpha} region rolling for compact rolling. 12 refs., 10 figs., 2 tabs.

Hashimoto, S.; Tsukatani, I.; Kashima, T.; Miyoshi, T. [Kobe Steel, Ltd., Kobe (Japan)

1998-04-01

336

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

337

Numerical analysis of small recessed silicon carbide grinding wheels  

Directory of Open Access Journals (Sweden)

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

M.J. Jackson

2010-11-01

338

Methodology for automatic selection of passes in surface grinding  

Directory of Open Access Journals (Sweden)

Full Text Available 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, those with the best results are presented in this article. Tests carried out in a surface-grinding machine have shown the success of the algorithms developed for pass extraction.

Fábio R. L. Dotto

2007-03-01

339

Grinding of coals in an impact reflecting grinder for the metallurgical combine im. K. Gottval'de  

Energy Technology Data Exchange (ETDEWEB)

Comparative tests are conducted of an impact reflecting grinder of the PS 1165-61 type of the Prsherovsk machine building factory and an improved hammer mill 1600X1600 during grinding of coal for coking. The criteria of effectiveness of the mechanisms during the grinding of coals and the conditions for producing the required granulometric composition of the ground coal are examined. The results of long term tests of the grinder are cited. The required output of fine fractions for coking with stoking of a charge is produced only for easily ground coking coals. For fatty and gaseous coals, as well as for coking with packing of the charge, the required fineness of grinding is not achieved. Considering that with a comparatively high productivity (200 t/h), the impact reflecting grinders PS 1165-61 have low specific expenditure of electric energy (1.7 kWt per h/t), it is recommended to refine these grinders for the possibility of their use in the coke chemical factories of Czechoslovakia.

Mohyla, J.; Stuchlik, V.; Zidek, J.

1981-01-01

340

Inflation Without Slow Roll.  

Science.gov (United States)

We draw attention to the possibility that inflation (i.e. accelerated expansion) might continue after the end of slow roll, during a period of fast oscillations of the inflation field Mu. This phenomenon takes place when a mild non-convexity inequality is...

T. Damour V. F. Mukhanov

1997-01-01

 
 
 
 
341

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.

Bech, Jakob Ilsted

2014-01-01

342

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

International Nuclear Information System (INIS)

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

1993-01-01

343

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2010-01-01

344

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

345

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...

2009-01-01

346

Teeth Grinding: Is Emotional Stability related to Bruxism?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

347

Investigation of Precision Grinding Process for Production of Silicon Diaphragms  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The application of precision grinding for the formation of a silicon diaphragm is investigated. The test structures involved 2–6 mm diam diaphragms with thicknesses in the range of 25–150 mm. When grinding is performed without supporting the diaphragm, bending occurs due to nonuniform removal of the silicon material over the diaphragm region. The magnitude of bending depends on the final thickness of the diaphragm. The results demonstrate that the use of a porous silicon...

Perova, Tania

2002-01-01

348

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

349

Optimizing the Grinding Process for Ceramic Materials; TOPICAL  

International Nuclear Information System (INIS)

There is probably no such thing as an optimized grinding process that stays optimized, but we should still strive for one. There is a strong need for standardized test methodologies that can be conducted in a production environment at reasonable costs and without sophisticated instrumentation. There is a need for better analytical models whose results closely match real-world grinding processes. Accurate measurement of wheel performance and wheel wear is a key enabling technology that needs further work and standardization

2001-01-01

350

Grinding media of Zr O2-Y2 O3  

International Nuclear Information System (INIS)

This paper describes an experiment carried out to test Yttria 3 mol% stabilized zirconia as a grinding media. The Powders were produced in experimental operations of a wet chemical coprecipitation process at the Zirconium Pilot Plant in IPEN. The stabilised zirconia powders obtained were cold pressed in to cylindrical shapes and sintered at 15000 C for hour. The ceramics produced presented good wear resistance and were found to be efficient as zirconia powders grinding media. (author)

1994-06-18

351

Influence of different grinding processes on residual stress  

International Nuclear Information System (INIS)

This investigation was made in order to find out a distribution of residual stress on the surfaces ground under various grinding conditions obtained by changing an actual depth of cut, number of grinding and a grinding process under a constant state of a chip cross sectional area. The surfaces of the specimens were ground by only up cut, only down cut and both up and down cut, respectively. The experimental data were analyzed by using both the Doelle-Hauk method and the integral method which takes into account of the stress gradient. As a result, the residual stress on the surface of one pass grinding showed higher tensile stress when a larger actual depth of cut took place. And the residual stress of down cut grinding was higher than that of up cut. By repeating another re-grinding on the same surface, the residual stress translated into a compressive stress and then converged into a certain level. On the contrary, the stress gradient changed to positive side in such case. (author)

1985-01-01

352

Use of In-Process EDM Truing to Generate Complex Contours on Metal-Bond, Superabrasive Grinding Wheels for Precision Grinding Structural Ceramics.  

Science.gov (United States)

This paper presents recent work performed at Lawrence Livermore National Laboratory to develop cost-effective, versatile and robust manufacturing methods for grinding precision features in structural ceramics using metal-bond, superabrasive grinding wheel...

M. A. Piscotty P. J. Davis T. T. Saito K. L. Blaedel L. Griffith

1997-01-01

353

Dynamic model of a grinding fan  

Energy Technology Data Exchange (ETDEWEB)

Explains that a model representing the dynamic characteristics of the MV 3300/800/490 grinding fan (which is used in the Primorsk power plant to prepare brown coal from the Bikin deposit) must be sufficiently compact to use with existing technology but must also be accurate. The model produced is based on a simplifed structural diagram and certain variables are treated as invariables (e.g. fuel density and moisture content, fuel layer thickness). Uses a system of differential equations (material balance equation, thermal balance equation, etc.) to describe various functions, e.g. drying the fuel, blending the fuel entering the grinder, the grinder-separator system and various input operations, such as a gradual change in the fuel flow rate equal to 10% of its rated value (these input operations are listed in tabular form). Explains that the model is considerably more accurate if real data are used rather than design values to describe parameters such as dust concentration in the air flow, temperature distribution etc., as they may deviate considerably from the specified values. 7 refs.

Zhitkevich, I.V.

1988-01-01

354

Forecasting the Reliability of Automated Grinding Systems on the Basis of Young’s Modulus of Grinding Wheels  

Science.gov (United States)

The paper presents the model of procedure and the results of forecasting the operational reliability of conventional grinding wheels applied to automated production systems. The forecasting was issued on the basis of Young’s modulus of these tools obtained from preoperational acceptance inspection. The model was verified during the process of internal grinding of bearing rings. Investigations were applied to 100 ceramic grinding wheels with the same characteristics. As a criterion for operational reliability were assumed: the grinding wheels radial wear ?rs, the maximum spindle power demand Pc and the arithmetical mean deviation of the roughness profile Ra. It was demonstrated that the operational reliability of tools under investigations was strictly interrelated the modulus E. Therefore; it can be used as a prognostic criterion for reliability of the system including these tools.

SŁOWIŃSKI, Bronisław

355

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 experime...

2012-01-01

356

Nondestructive evaluation of martensite content in the microstructure of rolled steel wire  

International Nuclear Information System (INIS)

In the microstructure of carbon steel wires, produced on wire rolling mills with controlled cooling, martensite in a certain amount can be formed. Martensite lowers the ductility of the material. An electromagnetic method for nondestructive evaluation of this martensite content had been developed for an in mill quality check. With this method the influence of microstructural stresses on relative permeability is measured. Under in mill conditions, a rejection level for the martensite content of 1.5% abs. can be granted. The use of this new method saves about 60% of the expenses for metallographic examinations. (orig.)

1984-07-01

357

Nondestructive evaluation of martensite content in the microstructure of rolled steel wire  

Energy Technology Data Exchange (ETDEWEB)

In the microstructure of carbon steel wires, produced on wire rolling mills with controlled cooling, martensite in a certain amount can be formed. Martensite lowers the ductility of the material. An electromagnetic method for nondestructive evaluation of this martensite content had been developed for an in mill quality check. With this method the influence of microstructural stresses on relative permeability is measured. Under in mill conditions, a rejection level for the martensite content of 1.5% abs. can be granted. The use of this new method saves about 60% of the expenses for metallographic examinations.

Polanschuetz, W.

1984-07-01

358

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

Directory of Open Access Journals (Sweden)

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

A.T. Siddiqui

2006-12-01

359

Studying possibilities to improve the functional properties of metallurgical rolls  

Directory of Open Access Journals (Sweden)

Full Text Available Thc paper prcscnts rcsults nT invcst igations and at~thors' opinion on improving functional propcrtics of mciall urgicnl rolls cast fromGZOOCrMoNi 4-9-3 cast wccl. onc nf most oftcn ilscd lor rolls in scction mills. Thcsc mills Icn~urcq uickcr than flat rolls wear or 1001'spass. whar rcquircs morc Crcqocnt rcpcncr;lt ion. 'Thc machining rcquircs n rclat ivcly low hardness, which is cnsurcd hy ~ h pcc arliiic matrixof casr steel strldid. 7 % ~au thors silggcst 10 achicvc thc optimisntion o f tribologicnl propcnics through adji~stmcno~r ~ h cch cinicalcompsizion odand modificat ioll of rhc hcat trcatmcnt. In thc study prcscntcd only t hc carbon comcnt was sliyhtly incrcascd (havingciirhiclc-forming clcmcnts in Y icw rcst~ltingi n thc incrcnse in lcdcburitic carbides. Il owcvcr, !his most nhvious way or improving thcahrasivc wcar rcsisrnncc incrcascs rhc ~brcaot f rolls cracking and ~hcrcforcrc quircs verification using ttlc iracii~rc~ ncchanicsm cthod.Szaziaical analysis of random1 y sclcctcd fcw dozens of rolls havc shown Tor this gradc or cast stccl a trcnd to rcducc thc carbon contcnzby ~ h ~cn :~nurihcturcmr. ilintilining ir at thc lowcr rangc of limirs spccificd by thc standard and not to incrcasc i t . Thc analysis or thc wcnrmcchmism or suriaccs or worn out mlls madc of G2OOCrMoNi 4-3-3 cast stecl allows making suggestions on thc possihilit ics of hcatrrcarmcnt changes, what aEso has hccn prcscnrcd in ~ h pc a p .

Z. Stradomski

2008-03-01

360

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

1978-01-01

 
 
 
 
361

Mechanical properties of chromium steels for back up rolling rolls  

International Nuclear Information System (INIS)

Back up rolling rolls are very large mechanical components which have to be designed to withstand very high contact stresses produced, under the rolling load, in the region between the working and the back up rolls, along with severe wear actions. In this investigation, the thermal treatment (bainitic isotermic quenching followed by several temper treatments) of these components is described and their most characteristic properties related to the in-service behaviour of these products are determined, using hardness, compression, fracture toughness and sliding wear tests. (Author) 7 refs

2003-01-01

362

Critical parameters for grinding large sapphire window panels  

Science.gov (United States)

Advances in optical manufacturing and testing technologies for sapphire material are required to support the increasing use of large-aperture sapphire panels as windscreens for various electro-optical system applications. Single surface grinding is a crucial process step in both the figuring and finishing of optical components. Improper grinding can make subsequent polishing operations more difficult and time consuming. Poor grinding can also lead to the introduction of surface stress and sub-surface damage which can affect critical opto-mechanical performance characteristics such as strength and durability. Initial efforts have been completed at Exotic Electro-Optics under the funding of the Office of Naval Research and the Air Force Research Laboratory to investigate a number of process enhancements in the grinding of a-plane sapphire panels. The information gained from this study will ultimately provide a better understanding of the overall manufacturing process leading to optimized process time and cost. EEO has completed two sets of twelve-run Plackett-Burman designs of experiment (DOE) to study the effects of fundamental grinding parameters on sapphire panel surfaces. The relative importance of specific process parameters on window characteristics including surface roughness, stress, sub-surface damage are reported.

Bashe, Joseph R.; Dempsey, Gene; Akwani, Ikerionwu A.; Jacoby, Keith T.; Hibbard, Douglas L.

2007-05-01

363

Development of morphology in laser dressed grinding wheels  

Directory of Open Access Journals (Sweden)

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

M.J. Jackson

2007-05-01

364

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

365

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

366

Energy saving processes in the production of flat rolled steel products. Energieeinsparung bei der Herstellung von Flacherzeugnissen aus Stahl  

Energy Technology Data Exchange (ETDEWEB)

On the medium-wide strip mill of the Thyssen AG in Berlin, milling experiments were carried out with the aim to change the quality of hot-rolled steel in such a way that cold-rolled steels or flat products can be substituted. The application of this hot-rolled steel will make some of the next production and/or heat treatment steps unnecessary, so that the substitution will be connected with energy savings. Apart from low-carbon steel coils of ferritic, highly corrosion-resistant micro-alloyed structural steels and dual-phase steels were manufactured. With the successful closing of the experiments, the aim to save energy has been reached, and hot-rolled steel has been made more competitive.

Angele, B.; Maid, O.

1983-11-01

367

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

368

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...

369

Rolling G_2 Moduli  

CERN Document Server

We study the time evolution of freely rolling moduli in the context of M-theory on a G_2 manifold. This free evolution approximates the correct dynamics of the system at sufficiently large values of the moduli when effects from non-perturbative potentials and flux are negligible. Moduli fall into two classes, namely bulk moduli and blow-up moduli. We obtain a number of non-trivial solutions for the time-evolution of these moduli. As a generic feature, we find the blow-up moduli always expand asymptotically at early and late time.

Lukas, A; Lukas, Andre; Morris, Stephen

2004-01-01

370

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

371

In-process grinding monitoring through acoustic emission  

Directory of Open Access Journals (Sweden)

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

Paulo R. Aguiar

2006-03-01

372

Potential release of carbon nanotubes from their composites during grinding  

International Nuclear Information System (INIS)

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.

2013-04-10

373

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.)

1979-08-01

374

Grinding wheel condition monitoring with boosted minimum distance classifiers  

Science.gov (United States)

Grinding wheels get dull as more material is removed. This paper presents a methodology to detect a 'dull' wheel online based on acoustic emission (AE) signals. The methodology has three major steps: preprocessing, signal analysis and feature extraction, and constructing boosted classifiers using the minimum distance classifier (MDC) as the weak learner. Two booting algorithms, i.e., AdaBoost and A-Boost, were implemented. The methodology was tested with signals obtained in grinding of two ceramic materials with a diamond wheel under different grinding conditions. The results of cross-validation tests indicate that: (i) boosting greatly improves the effectiveness of the basic MDC; (ii) over all A-Boost does not outperform AdaBoost in terms of classification accuracy; and (iii) the performance of the boosted classifiers improves as the ensemble size increases.

Liao, T. Warren; Tang, Fengming; Qu, J.; Blau, P. J.

2008-01-01

375

REVIEW OF DRESSING AND TRUING OPERATIONS FOR GRINDING WHEELS  

Directory of Open Access Journals (Sweden)

Full Text Available 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 the dressing process, so continuous efforts are made to develop or adopt a technique that gives the best result while fulfilling the maximum number of factors. This can be accomplished by comparing the present techniques on the same ground. With this aim, the unconventional techniques with in-process configuration were developed that have several advantages over theirconventional counterparts.

UJJAWAL MAYANK SRIVASTAVA

2013-01-01

376

Improved spray dry scrubbing through grinding of FGD recycle material  

Energy Technology Data Exchange (ETDEWEB)

A laboratory size spray dry scrubbing unit consisting of a spray dryer and a pulse jet baghouse was used to study the effect of grinding recycle waste on SO/sub 2/ removal across the spray dryer and on sorbent utilization. The equipment treats simulated flue gas with a dry flow rate of 1.5 m/sup 3/ h/sup -1/ (stp) and utilizes an ultrasonic nozzle for atomization. The apparatus was initially tested over a broad range of operating conditions; a close agreement in SO/sub 2/ removal was found with data from much larger units. The effect of grinding the FGD recycle material on the SO/sub 2/ removal across the spray dryer was found to be great. Grinding the recycle material can enhance the SO/sub 2/ removal efficiency to a level comparable to operation with a large excess of fresh lime. 24 refs.

Klingspor, J.S.

1987-07-01

377

Effect of stearic acid on the morphological and structural evolution of mechanically milled Nb-based powder  

Science.gov (United States)

Nb-based powder was fabricated via mechanical grinding. The influence of stearic acid on the grinding process was studied. The structural evolution and morphological evolution of the milled powder were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analysis. It is indicated that an appropriate amount of stearic acid accelerates the particle refinement process and favors the production of superfine Nb-based particles with good dispersivity and high activity. However, an inappropriate amount of stearic acid has an adverse effect on the refinement process.

Zhang, De-zhi; Qu, Xuan-hui; Qin, Ming-li; Zhang, Lin; Lu, Xin

2012-11-01

378

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

Science.gov (United States)

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

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

2009-07-01

379

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

Science.gov (United States)

Flour milling is a grinding process to produce flour from wheat through comprehensive stages of grinding and separation. The primary energy is required to provide power used in grinding of wheat. In wheat milling, tempering is the process of adding water to wheat before milling to toughen the bran and mellow the endosperm. Gravity flow of the wheat is utilized to rotate the dampener wheel with cups to add water. Low cost gravity flow operated small electricity generator retrofit kit for dampener was designed and developed to justify low cost energy production without expensive solutions. Results of statistical analysis indicated that there was significant difference in mean values for voltage, rpm and flow rate at the 95% probability level. The resulted maximum mechanical power and measured electrical power were 5.1 W and 4.9 W respectively at wheat flow rate of 1.6 Kg/s and dampener wheel rotational velocity of 4.4 rad/s. PMID:24426010

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

2013-10-01

380

Size-reduction and sorting behavior in sieve hammer mills  

Science.gov (United States)

Experiments were performed in a continuously operating sieve hammer mill to determine the duration of presence of the material to be ground in the size reduction machine. The test stand, analysis techniques, evaluation methods, and selection and production of samples are described. It is shown that the duration of presence of the material in the grinding space of the mill is approximately comparable to that in an ideal mixer. The type of sieve casing has an essential effect on the duration of presence. A combined model for the description of the size reduction and sorting behavior which allows the determination of the process coefficients (size reduction speed, sorting speed, mass transition coefficient) and their dependence on the different parameters, was developed.

Schallnus, Harald

 
 
 
 
381

Comparative Study of Grinding at Constant Force and Constant Speed Dipping . Comparaison de la Rectification a Force et a Vitesse de Plongee Constantes.  

Science.gov (United States)

The application of grinding with constant load to external grinding, a process introduced for internal grinding instead of grinding with constant descent velocity, is discussed. Geometrical precision, surface finishing, time, and costs for external grindi...

A. Decneut

1972-01-01

382

Investigations upon the indefinite rolls quality assurance in multiple regression analysis  

Energy Technology Data Exchange (ETDEWEB)

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

Kiss, I.

2012-11-01

383

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.)

2007-01-01

384

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

385

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

386

Study of thresholds to burning in surface grinding process  

Directory of Open Access Journals (Sweden)

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

P. R. de Aguiar

2005-06-01

387

Efficient grinding and polishing processes for asphere manufacturing  

Science.gov (United States)

The increasing use of aspheres in a variety of optical systems has pushed the industry to become more efficient at its manufacturing processes. Non-optimized grinding techniques can cause excessive sub-surface damage and mid-spatial frequency errors which can be both time consuming and difficult to remove during polishing. The SCGa 100 grinder and SCPa 100 polisher provide unique platforms for asphere manufacturing. The SCGa 100 uses optimized kinematics to create a stiff and rigid platform which minimizes grinding errors and artifacts. Subsequently, polishing time on the SCPa 100 is decreased reducing the risk of altering the aspheric shape. This process improves surface quality while simplifying manufacturing.

Hinn, Markus; Pisarski, Alex

2013-09-01

388

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

389

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

390

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...

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

2003-01-01

391

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...

2011-01-01

392

Solfach at Middle Mill  

Solfach at Middle Mill Last updated 21:00 on 07/04/2014 Summary The river level at Middle Mill is 0.32 metres. This measurement was recorded at 21:00 on 07/04/2014. The typical river level range for this location is between 0.15 metres and 0.51 metres. The highest river level recorded at this location… Related Searches: river level data middle mill

393

Numerical simulation of a hot rolling process  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the findings of the effects of rolling parameters on the work roll undergoing thermal cycles through numerical simulation using the finite element method. The rolling parameters investigated are the location of the spray nozzle, the coolant spray flux, and the initial work roll temperature. The findings show that the spray nozzle is best placed near the exit of the roll bite for minimum fatigue stress. Firecracking can be eliminated by providing a large cooling flux through spraying. The initial temperature of the work roll have little effect on the roll life, but does have some influence on the quality of the rolled product.

Tso, C.P.; Tan, F.L.

1999-07-01

394

Telahionnan kehittäminen  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis was done for UPM-Kymmene’s River mills during the spring of 2010. The main goal of this thesis was to improve the roll grinding in the Kaipola’s main grinding shop and to do research of the latest on-site grinding technology.

2010-01-01

395

Grinding performance of pellet prepared using nanosize ceria particles  

International Nuclear Information System (INIS)

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

2006-02-09

396

Grinding of Cast Iron with Wheels Made of Superhard Materials.  

Science.gov (United States)

Optimum grinding conditions for cast iron with wheels made of superhard materials were determined. Type PP 250 x 10 wheels made of metallized and non metallized diamond and various brands of CBN with 125/100 grains at 100 % concentration on metellic M0 16...

N. J. Korz

1982-01-01

397

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.

Michelle K. McGinn

2010-05-01

398

Automatic programming of grinding robot restoration of contours  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

1995-01-01

399

Global analysis of aerodynamics deflectors efficiency in the grinding process  

Directory of Open Access Journals (Sweden)

Full Text Available The conventional grinding methods in some cases are not very efficient because the arising of thermal damages in the pieces is very common. Optimization methods of cutting fluid application in the grinding zone are essential to prevent thermal problems from interaction of the wheel grains with the 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. 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

2006-06-01

400

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.

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

 
 
 
 
401

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/cm2

1995-05-08

402

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

403

Slow hot rolling in direct linkage with thin slab and strip continuous casting: Effect on the evolution of austenite grain  

Energy Technology Data Exchange (ETDEWEB)

This work was carried out in context with the development of strip casting with the single-belt process. In this new process the hot rolling is performed in-line with considerably lower velocity than in conventional hot rolling. It is of interest to study the effect of low rolling speed on the material properties. Based on a finite element model used to predict the thermomechanical behaviour of the strip in tandem mills, the microstructural evolution of austenite was computed. The parameter studies were carried out over a wide range of volumetric flow rate extending from that in thin slab casting to that in conventional finishing rolling. They demonstrate that the ''slow hot rolling'' can produce a fine grain of austenite. It is found that the final grain size of austenite is about the same for the two processes under the condition that strip thickness behind the last stand is the same. (orig.)

Zhou, S.; Schwerdtfeger, K. [Techn. Univ. Clausthal (Germany). Inst. fuer Metallurgie

2003-12-01

404

Controlled cooling technology for bar and rod mills -- Computer simulation and operational results  

Energy Technology Data Exchange (ETDEWEB)

The Controlled Cooling Technology (CCT) developed by SMS to simulate the rolling process and automatic control of the water cooling sections is presented. The Controlled Rolling and Cooling Technology (CRCT) model is a key part of the CCT system. It is used to simulate temperature management for the rolling stock on the computer before the actual rolling process takes place. This makes it possible to dispense with extensive rolling tests in the early stages of project planning and to greatly reduce the extent of such tests prior to the start of commercial production in a rolling mill. The CRCT model has been in use at Von Moos Stahl Ag for three years. It demonstrates that, by targeted improvement of the set-up values in both the technology and the plant, it is possible to improve microstructure quality and achieve better geometrical parameters in the rolled products. Also, the results gained with the CCT system in practical operation at the Kia Steel Bar Mill, Kunsan, Korea, are presented.

Mauk, P.J.; Kruse, M.; Plociennik, U. [SMS Schloemann-Siemag AG, Dusseldorf (Germany)

1995-09-01

405

Rolling of microalloyed magnesium sheets  

Energy Technology Data Exchange (ETDEWEB)

This paper described a rolling process for a micro-alloyed zinc-manganese (Zn-Ca-Ag-Mn) magnesium alloy. The micro-alloyed magnesium alloy L1 was investigated in order to achieve a finer grain structure and to avoid normal grain growth during rolling. Rolling parameters included billet temperature; rolls temperature and rolls radius; rolling speed; and lubrication. Standard tensile tests were conducted with the rolled alloy L1 flat specimens at room temperature with a test length of 50 mm and a test width of 12.5 mm. Specimens heat treated at 100 degrees C and 200 degrees C showed good balance of strength and elongation. Elongation increased with increasing heat treatment times. Results of the tests demonstrated that the Zn-Ca-Ag-Mn alloy L1 showed exceptionally high elongations to fracture at room temperatures. A pronounced work hardening regime was also observed. It was concluded that the grain structure of the L1 alloy was not influenced after heat treatments until temperatures reached 350 degrees C for 20 minutes. Significant grain coarsening occurred after preliminary heat treatments of 400 degrees C. 7 refs., 1 tab., 6 figs.

Sotirov, N.; Riemelmoser, F.O.; Kuhlein, M.; Kettner, M. [ARC Leichmetallkompetenzzentrum GmbH, Ranshofen (Austria); Uggowitzer, P.J. [ETH Zurich, Zurich (Switzerland). Dept. of Materials, Laboratory of Metal Physics and Technology; Spencer, K. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Materials Technology Lab

2007-07-01

406

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 characteristic features. The presence of catalytic metal particles seems to be a prerequisite for the hydrogenation of graphite under hydrogen by mechanical grinding

2004-04-25

407

Measuring the enrichment of fly-ash in cement grinding on the basis of its natural radioactivity  

International Nuclear Information System (INIS)

A method is described for measuring the fly-ash content in different products of cement grinding. This method is based on measuring the natural radioactivity concentrations of the cement components. As fly-ash - originating from coal-fired thermal power stations - contains the radioactive elements of coal in concentrated form, the radioactivity concentration of the fly-ash is higher than that of other cement additives. On the basis of the activity concentrations of cement components, the fly-ash concentrations in different areas of an operating cement ball mill were determined. It was found that the enrichment of fly-ash in the fine fraction-parallel with its impoverishment in the coarse fraction-was not as great as has been supposed because of its smaller particles. (author)

1986-01-01

408

Rolling tool calibration for cold rolling of tubes  

International Nuclear Information System (INIS)

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

1986-06-18

409

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

410

High coercivity induced by mechanical milling in cobalt ferrite powders  

Science.gov (United States)

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

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

2013-10-01

411

THE STUDY OF SCALE FORMATION ON HOT ROLLED INGOTS AND BILLETS  

Directory of Open Access Journals (Sweden)

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

GHEORGHE VLAICU

2010-06-01

412

AMAX for Flint Mill  

AMAX for Flint Mill Back to station AMAX Data for: Wharfe at Flint Mill (27002) QMED = 230.6m 3/s Note: Place the mouse cursor over a column heading to view a description of the data in that column Rank Water Year Date Time Stage Flow Rating Source Ref Available Data Comments 4 1936-37 14/12/1936 00…

413

Corn Wet Milling Lab  

Science.gov (United States)

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

Olson, Eric; Warren, Noreen

2008-10-27

414

Ratings for Loverley Mill  

Ratings for Loverley Mill Back to station Rating History for: Allen at Loverley Mill (43010) Note: Place the mouse cursor over a column heading to view a description of the data in that column Ref Limb Details Equation Start Date Max Stage End Date 4 a new 2 hatches closed Q = 3.862*(h + 0.00)^1.507…

415

Compound taper milling machine  

Science.gov (United States)

Simple, inexpensive milling machine tapers panels from a common apex to a uniform height at panel edge regardless of the panel perimeter configuration. The machine consists of an adjustable angled beam upon which the milling tool moves back and forth above a rotatable table upon which the workpiece is held.

Campbell, N. R.

1969-01-01

416

AMAX for Sprint Mill  

AMAX for Sprint Mill Back to station AMAX Data for: Sprint at Sprint Mill (73009) QMED = 42.2m 3/s Note: Place the mouse cursor over a column heading to view a description of the data in that column Rank Water Year Date Time Stage Flow Rating Source Ref Available Data Comments 8 1969-70 17/09/1970 07…

417

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

Science.gov (United States)

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

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

418

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.

2011-01-17

419

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

420

Vitreous bond CBN high speed and high material removal rate grinding of ceramics  

Energy Technology Data Exchange (ETDEWEB)

High speed (up to 127 m/s) and high material removal rate (up to 10 mm{sup 3}/s/mm) grinding experiments using a vitreous bond CBN wheel were conducted to investigate the effects of material removal rate, wheel speed, dwell time and truing speed ratio on cylindrical grinding of silicon nitride and zirconia. Experimental results show that the high grinding wheel surface speed can reduce the effective chip thickness, lower grinding forces, enable high material removal rate grinding and achieve a higher G-ratio. The radial feed rate was increased to as high as 0.34 {micro}m/s for zirconia and 0.25 {micro}m/s for silicon nitride grinding to explore the advantage of using high wheel speed for cost-effective high material removal rate grinding of ceramics.

Shih, A.J.; Grant, M.B.; Yonushonis, T.M. [Cummins Engine Co., Inc., Columbus, IN (United States); Morris, T.O.; McSpadden, S.B. [Oak Ridge National Lab., TN (United States)

1998-08-01

 
 
 
 
421

Allowable variation of cold-rolled strip transverse profiles in high tension  

Science.gov (United States)

The formation mechanism of the cold-rolled strip shape with high tension was studied. An advanced method to calculate the allowable variation of strip transverse profiles was established by the strip buckling criterion, which can be more properly used in cold rolling. With this method, the aim allowable variation of the product strip transverse profile and the required transverse profile range of incoming strips can be reached. Besides, this method has been successfully applied in a domestic tandem cold mill, and the transverse profile range of incoming strips suggested with this method is more practicable and complete. Consequently, the good performance is acquired.

Wang, Xiao-Chen; Yang, Quan; Du, Xiao-Zhong; Jiang, Zheng-Yi

2010-10-01

422

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

International Nuclear Information System (INIS)

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

2006-09-01

423

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

Science.gov (United States)

This paper discusses the influence of chemical composition on the final electromagnetic properties in higher permeability material. Furthermore, the effect of the hot rolling practice and the end of austenite transformation temperature range on the hot band microstructure is described. The magnetic polarization J5000 better than 1.7 T, using hot rolling conditions 40 mm transfer bar thickness, finish mill entry temperature 1000 °C, and finishing temperature 800-840 °C and after decarburization heat treatment and grain growth treatment, was obtained.

Hu?ady, J.; ?erník, M.; Hilinski, E. J.; Predmerský, M.; Magurová, A.

2006-09-01

424

Thermal expansion of rolled and extruded uranium  

International Nuclear Information System (INIS)

The authors report the results of their studies of the thermal expansion characteristics of hot- and warm-rolled ?-U plate and hot-extruded pipe. The hot-rolled plate had a high coefficient of thermal expansion (CTE) in the rolling direction and a low CTE in the transverse direction. This trend was reversed in both as-warm-rolled plate and plate that was both warm rolled and annealed. In pipe that was hot extruded at large reduction ratios, it was possible to correlate the CTE for the extrusion, radial and circumferential directions with the CTE for rolling, transverse and normal directions in the hot-rolled plate. (Auth.)

1983-01-01

425

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

426

Chirality in Swiss Roll metamaterials  

International Nuclear Information System (INIS)

A numerical investigation is presented for the electromagnetic behaviour of Swiss Roll metamaterials that show considerable agreement with analytical theory. Their chiral design exhibits enormous chirality, at least 100 times larger than other chiral structures previously reported in the literature. This property ensures the change of a wave polarization by 900 in less than a wavelength. Hence, chiral Swiss Rolls support a negative refractive band for one-wave polarization, which is predicted analytically and calculated numerically.

2010-07-15