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Sample records for roll mill grinding

  1. The implementation of HPGR mills in existing grinding circuits

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

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

  2. Grinding arrangement for ball nose milling cutters

    Science.gov (United States)

    Burch, C. F. (inventor)

    1974-01-01

    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.

  3. Continuous grinding mill simulation using Austin's model

    Directory of Open Access Journals (Sweden)

    André Carlos Silva

    2012-01-01

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

  4. Evaluation of Recycle Grinding Performance in Flour Milling

    OpenAIRE

    Siti Mazlina Mustapa Kamal; Colin Webb

    2007-01-01

    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 ...

  5. Ultrafine grinding of muscovite in close packed media mill

    Energy Technology Data Exchange (ETDEWEB)

    Orumwense, O.A.; Forssberg, E. (Division of Mineral Processing, Luleaa University of Technology, Luleaa (SE))

    1990-01-01

    This paper presents the results of batch vibration milling of mica. Grinding time or energy input, and solid and dispersant concentrations were the variables. Product fineness is greatly influenced by energy input, solid concentration, and mill settings. Muscovite can be ground efficiently to a high degree of fineness at a relatively high energy expenditure. Particle shape is preserved or improved presumably due to the predominance of exfoliation as opposed to true fracture as the mode of particle breakage. (author).

  6. Breakage parameters for ultrafine grinding in stirred-media mills

    Energy Technology Data Exchange (ETDEWEB)

    Cho, H.; Hogg, R. [Pennsylvania State Univ., University Park, PA (United States)

    1995-12-31

    Ultrafine grinding into the micron and sub-micron size range is becoming increasingly important for a wide range of industries involving ceramics, chemicals, paints, coating, pharmaceuticals, coal and others. Investigations of long-time grinding of fine quartz (to about 80% passing 0.35 {micro}m) in a 0.6 liter stirred-media mill are described. Breakage rates and primary breakage distributions have been determined based on extensive characterization of the ground products by laser scatterings diffraction and gas adsorption. The results indicate that, while there is qualitative similarity between the breakage parameters for ultrafine and conventional (coarse) grinding, there are important, quantitative differences. In particular, it is found that primary breakage distributions become significantly narrower in the submicron sizes. The trend can be described using double-truncated log-normal distributions in which both a maximum (breaking) size and a grind limit are specified. The breakage distributions become progressively narrower as the size being broken becomes finer. Breakage rates follow a typical, consistent pattern in which the rate decreases with size according to a simple power law. Further decrease in the rates seems to occur after very long grinding times when the entire mill contents become finer than about 1 {micro}m. The effect is explained as a result of changes in the rate/size relationship in the submicron range.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-02-15

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

  9. ELECTRO-RESISTANCE METHOD OF CHECK A PROCESS GRINDING THE ROLLING BEARINGS

    Directory of Open Access Journals (Sweden)

    K. V. Podmasteryev

    2015-08-01

    Full Text Available Base a possibility of monitoring processes of grinding the rolling bearings with use electroresistance method of check. Is write of essence this method, are analyses his peculiarities, which are provide objective information on the condition a object by his grinding. Are consider the results of experimental researches the effective different diagnostically parameters, which are confirm a possibility of realization objective check of grinding the rolling bearings with use electro-resistance method.

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

    Directory of Open Access Journals (Sweden)

    Lek Sikong

    2008-05-01

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

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

    Scientific Electronic Library Online (English)

    U., Weber; D., Langlois.

    2010-03-01

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

  12. Tribology; Cold rolling mill roll; Hard chrome; Surface texturing.

    Directory of Open Access Journals (Sweden)

    Jos Lucio Gonalves Junior

    2012-12-01

    Full Text Available The present work analyzes the tribological behavior of surface modifications often used in cold rolling mill rolls. Different surface modifications were carried out on samples produced from a fragment of the rolling mill roll: i texturing; ii chromium plating; iii texturing with subsequent hard chrome plating; iv and hard chrome plating with subsequent texturing. Before the surface modifications the samples were heat treated and ground on both faces. Wear tests were performed using a reciprocating movement of a ball over flat configuration under a load of 9.8 N. It is observed that there is no significant change in the coefficient of friction as a function of surface modification. Surface texturing increases the wear of the counter body, while the hard chromium coating reduces it. The addition of hard chromium coating promotes the formation of a tribolayer on the counter body consisting of chromium and oxygen. On the other hand, for the samples without hard chrome coating, the tribolayer consists of iron and oxygen

  13. Metallurgical analysis of spalled work roll of hot strip mill

    International Nuclear Information System (INIS)

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

  14. Numerical simulation of grinding phenomena in ball media mills and its applications; Baitai mirunai no funsei gensho no suchi shimyureshon to sono oyo

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Toyokazu [Hosokawa Micron Corp., Osaka (Japan)

    1999-10-01

    For efficient grinding, it is necessary to choose appropriate mill among many types of machines according to feedstocks, their grain size and requested grain size for products. For fine grinding of high hardness ceramics, generally jet mill, roller mill and ball media mill are applied. Effects of milling machine and grinding condition on the force added to particles from media in the media mill are examined, and relationship between grinding process and grinding rate is explained. Movement simulation of ball in media mill by discrete element method, relationship among media collision, grinding rate and grinding condition, and change of media flow by setting condition were illustrated. (NEDO)

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

    OpenAIRE

    Farzaneh Ahmadzadeh; Jan.Lundberg

    2013-01-01

    The liner of an ore grinding mill is a critical component in the grinding process, necessary for both high metal recovery and shell protection. From an economic point of view, it is important to keep mill liners in operation as long as possible, minimising the downtime for maintenance or repair. Therefore, predicting their wear is crucial. This paper tests different methods of predicting wear in the context of remaining height and remaining life of the liners. The key concern is to make decis...

  16. The Adaptive Control of Accuracy at Centerless Grinding of Rolling Bearings

    Science.gov (United States)

    Yalovoy, O. A.; Zakharov, O. V.; Kochetkov, A. V.

    2015-10-01

    The method of adaptive control of accuracy at centerless grinding is developed. This method is based on statistical modeling of Monte Carlo and considers basic data of measurement of roundness of details. Results of application of the method for control of the accuracy of processing of rings of rolling bearings are given.

  17. Continuous grinding kinetics of ethenzamide particles by fluidized-bed jet-milling.

    Science.gov (United States)

    Fukunaka, T; Golman, B; Shinohara, K

    2006-03-01

    Continuous grinding kinetics of Ethenzamide powder, as a model active pharmaceutical ingredient (API) was investigated by fluidized-bed jet-milling. Because the oversize fractions after the classification were well fitted by a modified Rosin-Rammler distribution function, an equation of grade efficiency curve was obtained, which was also characteristic of API. A continuous grinding model was developed on the basis of a batch model by using 1st Kapur function relating grinding rate, the grade efficiency curve, and the overall process flow model consisting of grinding, classification, and mixing zones. The residual ratio obtained was well fitted to the experimental results except for the particle size range smaller than 4 microm and larger than 100 microm. Furthermore, because the volume of the active grinding zone adopted as the fitting parameter was found to be 5 cm3 in all experiments and the value was considered to be appropriate dimensionally, this result supports the reliability of the model. PMID:16556539

  18. Structural causes of defects in a cast iron mill roll

    Directory of Open Access Journals (Sweden)

    J. Krawczyk

    2008-07-01

    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.

  19. Influence of pin and hammer mill on grinding characteristics, thermal and antioxidant properties of coriander powder.

    Science.gov (United States)

    Barnwal, P; Singh, K K; Sharma, Alka; Choudhary, A K; Saxena, S N

    2015-12-01

    In present study, influence of grinding (hammer and pin mills) and moisture content (range: 6.4-13.6% dry basis) on the quality traits of coriander powder were investigated. These include grinding parameters, colour parameters, specific heat, thermal conductivity, thermal diffusivity, glass transition temperature, essential oil, total phenolic content, total flavonoid content and DPPH scavenging (%) of coriander powder. For coriander seed, the geometric properties such as major, medium, minor dimensions, geometric mean diameter, arithmetic mean diameter, sphericity, surface area and volume of coriander seeds increased significantly with increasing moisture (6.4-13.6% db). For coriander powder, the grinding parameters such as average particle size, volume surface mean diameter and volume mean diameter increased significantly with increasing moisture (6.4-13.6% db). With the grinding method, the colour attributes of coriander powder such as L-value, a-value, b-value, hue angle and browning index varied significantly. It was observed that the specific heat followed second order polynomial relationship with temperature and moisture whereas thermal conductivity varied linearly with temperature and moisture content. The variation of glass transition temperature with moisture can be best represented in quadratic manner. Total flavonoid content (mg QE/g crude seed extract) and DPPH scavenging % activity of coriander powder is significantly affected by grinding methods. A lower value of specific heat was observed for hammer ground coriander powder as compared to pin mill ground coriander powder. The thermal conductivity of hammer mill ground coriander powder was higher as compared to pin mill ground coriander. It was observed that hammer mill yields more fine coriander powder in comparison to pin mill. The browning index was more in hammer mill ground coriander powder. PMID:26604351

  20. Optimum condition determination of Rirang uranium ores grinding using ball mill

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Piyas Palit; Hrishikesh R. Jugade; Arvind Kumar Jha; Souvik Das; Goutam Mukhopadhyay

    2015-01-01

    In hot rolling mills, premature failure of rolls is a major concern as it adversely affects the mill operation as well as production. Analysis of failed roll materials and actual rolling conditions in service are therefore necessary to understand the roll failure mechanism and thereby improve the wear resistance and extend the service life of rolls. The hot strip mill referred here consists of six stands wherein high chromium (Hi-Cr) iron rolls and Indefinite Chilled Double Poured (ICDP) c...

  2. Corrosion of Cast Iron Mill Plates in Wet Grinding

    OpenAIRE

    Anthony ANDREWS; Samuel KWOFIE

    2010-01-01

    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...

  3. Corrosion of Cast Iron Mill Plates in Wet Grinding

    Directory of Open Access Journals (Sweden)

    Anthony ANDREWS

    2010-12-01

    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.

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

    CERN Document Server

    Angleys, M

    2003-01-01

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

  5. Grinding media wear during mechanical alloying of Ni-W alloys in a spex mill

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, T.H.; Wang, Z. (Virginia Univ., Charlottesville, VA (United States))

    1992-09-15

    Mechanical alloying (MA) is utilized for producing powdered materials having intriguing properties and structures. Some of these materials manifest extended solid solubility. Mechanical alloying has also been used to synthesize equilibrium and nonequilibrium intermediate (or intermetallic) phases, amorphous materials and inorganic nonmetallics. In their laboratory the authors have been studying the amorphization of Ni-W alloys, accomplished by extended grinding in a SPEX mill. It was brought to The authors' attention (by the reviewer of a manuscript ) that perhaps the authors ought to be paying some attention to the effect of wear debris on the tendency for, and extent of, the amorphization the authors observed. This paper reports on the contamination that accompanies SPEX milling of No-W alloys. The authors will show that wear debris, while only a small fraction of the total grinding media charge, is sufficient to alter appreciably the composition of the milled powder.

  6. Behavior of grinding media in sand mill (I)

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-04-20

    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.

  7. Dry, fine grinding of dolomite with the Sala Agitated Mill SAM 7.5 - effects of grinding media and grinding additive; Trockene Feinstmahlung von Dolomit mit der Ruehrwerkskugelmuehle SAM 7.5 - Einfluss von Mahlkoerper und Mahlhilfsmittel

    Energy Technology Data Exchange (ETDEWEB)

    Forssberg, E. [Technische Univ. Luleaa (Sweden). Inst. fuer Aufbereitung; Wang, Y. [Technische Univ. Luleaa (Sweden). Inst. fuer Aufbereitung; Persson, H. [Technische Univ. Luleaa (Sweden). Inst. fuer Aufbereitung

    1995-05-01

    The effects of grinding media and grinding additives on such a grinding process with this mill have been investigated in some detail. It was indicated that 8 mm x 8 mm cylpebs were favourable for the grinding performance, as compared with 8 mm balls. Experimental results have shown that the smaller grinding media (4 mm balls) gave the better transfer of energy from the media to the material to be ground compared to the larger 8 mm balls and 8 mm x 8 mm cylpebs. Use of amine for dry grinding of dolomite only had a significant effect when the fine fractions built up in the mill. The reduction in energy consumption by the grinding additive might be due to adsorption of amine on the fine particles by influencing the mass transport within the mill. (orig.) [Deutsch] Mit dieser Muehle wurde der Einfluss von Mahlkoerpern und Mahlhilfsmitteln bei diesem Mahlverfahren untersucht. Dabei hat sich gezeigt, dass 8 mm x 8 mm-Cylpebs guenstiger fuer das Mahlverhalten sind als 8 mm-Kugeln. Gegenueber den groesseren 8 mm-Kugeln und den 8 mm x 8 mm-Cylpebs uebertragen die kleineren Mahlkoerper (4 mm-Kugeln) die Mahlkoerperenergie besser auf das Mahlgut. Der Einsatz von Aminen zur Trockenmahlung von Dolomit hatte nur dann einen wesentlichen Einfluss, wenn sich Feinstkorn in der Muehle bildete. Die Reduzierung des Energieverbrauches durch das Mahlhilfsmittel ist eventuell eine Folge der Adsorption von Aminen auf das Feinstkorn, das den Massentransport innerhalb der Muehle beeinflusst. (orig.)

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

    OpenAIRE

    Stephen Adegbite

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-12-01

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

  10. Effect of filling degree of grinding media on motion of media particle and grinding characteristics in horizontal type sand mill; Yokogata sand mill no ryudo kyodo to funsai tokusei ni oyobosu media ryushi no jutenritsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Teshiba, T.; Takao, M.; Komori, S.; Murakami, Y. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Yoshida, H. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1996-07-10

    The effect of filled ratio on flow characteristics of grinding media was investigated for a horizontal type sand mill, in which the internal blade and external cylinder counter rotated independently. The relationship between flow characteristics anal grinding performance was discussed by carrying out grinding tests of calcium carbonate. As a result, it was found that the grinding characteristics obtained for both rotation methods can be well correlated as a function of intensity of velocity fluctuations weighted by appearance frequency and the second power of filled ratio, where the reciprocal collision probability of media particles is taken into consideration. 6 refs., 2 tabs.

  11. Theoretical And Experimental Analysis Of Aluminium Bars Rolling Process In Three-High Skew Rolling Mill

    Directory of Open Access Journals (Sweden)

    Stefanik A.

    2015-06-01

    Full Text Available Technology of round bars rolling on a three-high skew rolling mills allows rolling of standard materials such as steel and aluminum, as well as new materials, especially hard deformable materials. The paper presents the results of theoretical and experimental rolling process of aluminum bars with a diameter of 20 mm. As the stock round bars with a diameter of 25 mm made of aluminum grade 1050A and aluminum alloy grade 2017A were used. The rolling process of aluminum bars has been carried out in a single pass. The numerical analysis was carried out by using computer program Forge2011. On the basis of theoretical research it has been determined the state of deformation, stress and temperature distribution during rolling of aluminum bars. In addition, the results of theoretical research allowed to determine the schema of the metal plastic flow in the roll gap. Verification of the theoretical research was carried out during the rolling of aluminum bars on the RSP 40/14 laboratory three-high skew rolling mill. From the finished bars were taken the samples to set the shape and compared with the results of theoretical research. Finished aluminum round bars were characterized by low ovality and good surface quality.

  12. Dependence of rates of breakage on fines content in wet ball mill grinding

    Science.gov (United States)

    Bhattacharyya, Anirban

    The following research fundamentally deals with the cause and implications of nonlinearities in breakage rates of materials in wet grinding systems. The innate dependence of such nonlinearities on fines content and the milling environment during wet grinding operations is also tested and observed. Preferential breakage of coarser size fractions as compared to the finer size fractions in a particle population were observed and discussed. The classification action of the pulp was deemed to be the probable cause for such a peculiarity. Ores with varying degrees of hardness and brittleness were used for wet grinding experiments, primarily to test the variations in specific breakage rates as a function of varying hardness. For this research, limestone, quartzite, and gold ore were used. The degree of hardness is of the order of: limestone, quartzite, gold ore. Selection and breakage function parameters were determined in the course of this research. Functional forms of these expressions were used to compare experimentally derived parameter estimates. Force-fitting of parameters was not done in order to examine the realtime behavior of particle populations in wet grinding systems. Breakage functions were established as being invariant with respect to such operating variables like ball load, mill speed, particle load, and particle size distribution of the mill. It was also determined that specific selection functions were inherently dependent on the particle size distribution in wet grinding systems. Also, they were consistent with inputs of specific energy, according to grind time. Nonlinearity trends were observed for 1st order specific selection functions which illustrated variations in breakage rates with incremental inputs of grind time and specific energy. A mean particle size called the fulcrum was noted below which the nonlinearities in the breakage trends were observed. This magnitude of the fulcrum value varied with percent solids and slurry filling, indicating that breakage rates were being influenced by the milling environment as a whole. Primarily, there was always an increase in the breakage rates of coarser fractions with an increase in the amount of fines in the particle population. Consequently, the breakage rates of the finer size fractions were observed to decrease with an increase in grind time. Similar trends were noticed for 2nd order specific selection functions, where incremental inputs of specific energy were provided to observe realtime trends in the nonlinearity of breakage rates closely. Although the breakage rates for coarser size fractions increase with an increase in the amount of fines, the nature of nonlinearities varied with extended grind times. 1st order and 2nd order energy-specific breakage rates were observed to notice the variation in trends with extended grind times. Implications of such nonlinearities in specific breakage rates of various materials were tested on predictive simulation techniques, using the normalized linear population balance model and compared with an incremental methodology of specific energy input.

  13. Digital technology for radiometric thickness gages in rolling mills

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-01

    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 0.130.15 (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 0.984.22 mm, 3680 kg m-3, 49119 kg m-3, 6001220 kg m-3, and 0.90.96, 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 8890 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).

  15. Aplicao de prensas de rolos em minrio de ferro High pressure grinding rolls for iron ore

    Directory of Open Access Journals (Sweden)

    Farley Santos Ribeiro

    2010-06-01

    Full Text Available O Projeto Minas-Rio, de propriedade da Anglo Ferrous Brazil, prev a utilizao de prensa de rolos para cominuio do undersize do peneiramento (-25,4 mm. Esta uma aplicao que se torna cada dia mais comum, porm relativamente nova em minrio de ferro. Foram realizados estudos no Centro de Pesquisa da Krupp/Polysius na Alemanha, com o objetivo de validar a aplicao de prensa de rolos para minrio de ferro, de determinar os principais parmetros usados no dimensionamento e de avaliar o impacto do aumento da umidade da alimentao na capacidade especfica e na distribuio granulomtrica do produto. Os excelentes resultados obtidos, nos ensaios em escala-piloto, somados aos ganhos financeiros da aquisio e operao, maior estabilidade do processo diante variaes de w i (work index e distribuio granulomtrica da alimentao, contriburam para aprovar, de forma irrestrita, a aplicao de prensa de rolos para cominuio de minrio 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.

  16. Aplicao de prensas de rolos em minrio de ferro / High pressure grinding rolls for iron ore

    Scientific Electronic Library Online (English)

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

    2010-06-01

    Full Text Available O Projeto Minas-Rio, de propriedade da Anglo Ferrous Brazil, prev a utilizao de prensa de rolos para cominuio do undersize do peneiramento (-25,4 mm). Esta uma aplicao que se torna cada dia mais comum, porm relativamente nova em minrio de ferro. Foram realizados estudos no Centro de Pesqu [...] isa da Krupp/Polysius na Alemanha, com o objetivo de validar a aplicao de prensa de rolos para minrio de ferro, de determinar os principais parmetros usados no dimensionamento e de avaliar o impacto do aumento da umidade da alimentao na capacidade especfica e na distribuio granulomtrica do produto. Os excelentes resultados obtidos, nos ensaios em escala-piloto, somados aos ganhos financeiros da aquisio e operao, maior estabilidade do processo diante variaes de w i (work index) e distribuio granulomtrica da alimentao, contriburam para aprovar, de forma irrestrita, a aplicao de prensa de rolos para cominuio de minrio 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.

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

    International Nuclear Information System (INIS)

    Dry grinding experiments on cement clinker were carried out using a laboratory batch ball mill equipped with torque measurement. The specific energy was found to be dependent on operating parameters and clinker environment. Additional compounds such as gypsum and pozzolanic tuff improve energy efficiency. The optimal parameters allowing maximising the energy efficiency factor were determined. Energy efficiency factors were obtained both on the crude material (size minus 2.8 mm) and on a sieved fraction (1-0.71 mm). They demonstrate that a low initial rate of breakage implies higher energy efficiency. On the contrary, conditions ensuring an initial maximal rate of breakage lead to an increase of the energy consumption

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

    OpenAIRE

    Ali Azadeh; Farid Ghaderi

    2006-01-01

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

  19. Development of rolling mill for rectangular orthodontic wires production

    OpenAIRE

    Totten, G.E.; A.I. Filho; C.A.R. Gouva; Neto, A.; L.C. Casteletti

    2007-01-01

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

  20. Development of rolling mill for rectangular orthodontic wires production

    Directory of Open Access Journals (Sweden)

    G.E. Totten

    2007-09-01

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

  1. Application of mechano-chemical synthesis for protective coating on steel grinding media prior to ball milling of copper

    Indian Academy of Sciences (India)

    Indranil Lahiri; K Balasubramanian

    2007-04-01

    One of the major sources of contamination during mechanical milling/alloying is from the surface erosion of the container and the grinding medium. This can either be prevented by using grinding medium and container of same material of the milled material or by adding a coating of the milled material on them. The paper describes the observations made during a mechano-chemical reaction, being used for coating the balls and vials in a planetary ball mill. Visual observation, XRD, optical micrography and EDS analysis were used to understand the progress of the reaction. Copper was successfully coated on the steel balls and vials. The method can easily be adopted in daily production purposes, prior to mechanical milling of a Cu-based powder for prevention of Fe contamination.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

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

    OpenAIRE

    Oluleke O. Oluwole; Olayinka Olaogun

    2011-01-01

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

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

    Czech Academy of Sciences Publication Activity Database

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

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

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

    OpenAIRE

    Krawczyk, J; J. Pacyna

    2010-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ali Azadeh

    2006-01-01

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

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

    Science.gov (United States)

    Rashidi Dashtbayaz, Samira

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

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

    Science.gov (United States)

    Raghavendra, H.; Bhat, K. L.; Udupa, K. Rajendra; Hegde, M. M. Rajath

    2011-01-01

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

  9. Numerical And Experimental Study On Producing Aluminum Alloy 6061 Shafts By Cross Wedge Rolling Using A Universal Rolling Mill

    Directory of Open Access Journals (Sweden)

    Tofil A.

    2015-06-01

    Full Text Available The paper presents a selection of numerical and theoretical results of the cross wedge rolling process for producing stepped shafts made of aluminum alloy 6061. The numerical modeling was performed using the FEM-based Simufact Forming simulation software. In the simulations, we examined the kinematics of metal flow and determined the distribution patterns of effective strains, temperatures, axial stresses and the Cockroft-Latham damage criterion. Variations in the rolling forces were determined, too. The numerical results were verified experimentally using a universal rolling mill designed and constructed by the present authors. This machine can be used to perform such processes as cross wedge rolling, longitudinal rolling and round bar cropping. During the experiments, we examined process stability and finished product geometry and recorded the torques. The experimental results confirm that axisymmetric aluminum alloy shafts can be produced by cross wedge rolling with two rolls. Last but not least, the experiments served to evaluate the technological potential of the rolling mill used.

  10. IMPROVEMENT PROCESS FOR ROLLING MILL THROUGH THE DMAIC SIX SIGMA APPROACH

    Directory of Open Access Journals (Sweden)

    Kunal Ganguly

    2012-09-01

    Full Text Available This project aims to address the problems that are facing a large aluminum company in a Developing Hot Rolling Mill Capabilities for Wider Widths Hard Alloys Rolling and b Eliminate down time due to strip /coil slippage during hard alloys 5xxx rolling at Hot Mill. The challenge for the company was to cater the fast changing export demand for Flat Rolled products with its existing resources. By applying Six Sigma principles, the team identified the current situation that the rolling mills operations were in. Si x Sigma DMAIC methodologies were use d in the project to determine the project's CTQ characteristics, defining the possible causes, Identifying the variation sources, establishing variable relationships and Implementing Control Plans. The project can be useful for any company that needs to fi nd the most cost efficient way to improve and utilize its resources.

  11. A small economical rolling mill for producing foils used as nuclear targets

    Energy Technology Data Exchange (ETDEWEB)

    Greene, J.P.; Thomas, G.E.

    1996-11-01

    A small, economical rolling mill has found extensive use in the Physics Division Target Development Laboratory for producing foils used in atomic and nuclear physics experiments. This apparatus is quite versatile for its size and enables a large fraction of our target foil requirements to be realized in-house. A description of the rolling mill and some examples of targets produced will be given.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

  14. Hot sheet rolling on continuous mill under plastic fluid friction conditions

    International Nuclear Information System (INIS)

    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

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

    Scientific Electronic Library Online (English)

    J. M., Glvez; Luis E., Zrate; H., Helman.

    2003-03-01

    Full Text Available A capital issue in roll-gap control for rolling mill plants is the difficulty to measure the output thickness without including time delays in the control loop. Time delays are a consequence of the possible locations for the output thickness sensor, which usually is located some distance away from t [...] he roll gap. In this work, a new model-based predictive control law is proposed. The new scheme is a neural network based predictive control structure which is applied to roll-gap control with outstanding results. It is shown that the neural network based predictive control permits to overcome the existing time delays in the system dynamics. The proposed scheme implements a virtual thickness sensor, which releases an accurate estimate of the actual output thickness. It is shown that the dynamic response of the rolling mill system can be substantially improved by using the proposed controller. Simulation results are presented to illustrate the controller performance.

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Kuosmanen, Petri

    2004-01-01

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  19. 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)

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

    OpenAIRE

    Yan Gao; Baoquan Jin; Hongjuan Zhang

    2013-01-01

    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 m...

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

    Czech Academy of Sciences Publication Activity Database

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

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

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

    International Nuclear Information System (INIS)

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

  3. Force prediction in cold rolling mills by polynomial methods

    Directory of Open Access Journals (Sweden)

    Nicu ROMAN

    2007-12-01

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

  4. 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)

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

    1995-05-10

    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.

  5. The effect of ZrO{sub 2} grinding media on the attrition milling of FeAl with Y{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Gedevanishvili, S.; Deevi, S.C

    2004-03-25

    Attrition milling of water and gas atomized FeAl was carried out with Y{sub 2}O{sub 3}, where ZrO{sub 2} was used as a grinding media in place of stainless steel balls to avoid contamination with Cr and C. Consolidation of the milled powders produced complex FeAl phases containing Zr which doubled the hardness and significantly improved the creep resistance as compared to that of unmilled and consolidated FeAl.

  6. Fluid mechanics of slurry flow through the grinding media in ball mills

    Energy Technology Data Exchange (ETDEWEB)

    Songfack, P.K.; Rajamani, R.K. [Univ. of Utah, Salt Lake City, UT (United States). Comminution Center

    1995-12-31

    The slurry transport within the ball mill greatly influences the mill holdup, residence time, breakage rate, and hence the power draw and the particle size distribution of the mill product. However, residence-time distribution and holdup in industrial mills could not be predicted a priori. Indeed, it is impossible to determine the slurry loading in continuously operating mills by direct measurement, especially in industrial mills. In this paper, the slurry transport problem is solved using the principles of fluid mechanics. First, the motion of the ball charge and its expansion are predicted by a technique called discrete element method. Then the slurry flow through the porous ball charge is tackled with a fluid-flow technique called the marker and cell method. This may be the only numerical technique capable of tracking the slurry free surface as it fluctuates with the motion of the ball charge. The result is a prediction of the slurry profile in both the radial and axial directions. Hence, it leads to the detailed description of slurry mass and ball charge within the mill. The model predictions are verified with pilot-scale experimental work. This novel approach based on the physics of fluid flow is devoid of any empiricism. It is shown that the holdup of industrial mills at a given feed percent solids can be predicted successfully.

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

    International Nuclear Information System (INIS)

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

  8. FEM SIMULATION OF THE TUBE ROLLING PROCESS IN DIESCHERS MILL

    Directory of Open Access Journals (Sweden)

    Zbigniew Pater

    2014-06-01

    Full Text Available This paper deals with the issue of numerical modelling of the piercing process of a thickwalled bush in a two-rolled skew rolling mill, equipped with guiding devices of Dieschers type. After a short characteristic of the subject matter, the developed geometric model of the process was discussed, with taking kinematics of tools movement and thermal phenomena present in metal during forming into consideration. Next, the results of calculations were presented in a form of fields of strain, damage criterion and temperature. Distributions of force parameters acting on particular tools during the process of bush rolling were also given.

  9. Fuzzy-Neural Control of Hot-Rolling Mill

    Directory of Open Access Journals (Sweden)

    Khearia Mohamad

    2010-12-01

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

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

    OpenAIRE

    Graaf, A., van de

    2002-01-01

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

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

    Directory of Open Access Journals (Sweden)

    J. Krawczyk

    2010-07-01

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

  12. Strip/Foil Rolling Mill Stochastic Excitation Model and Its Stability

    Directory of Open Access Journals (Sweden)

    Baoyu Xu

    2012-06-01

    Full Text Available Based on the stochastic rolling force data from aluminum hot strip tandem mill, the ARMA time series model and the stochastic excitation power spectral density (PSD model are established, and the stochastic rolling forces excitation model is established by utilizing Levenberg-Marquardt combined with generalized global planning algorithm. A two dimensional stochastic nonlinear dynamical model of rolls is presented considering the stochastic factor of the rolling force. The Hamilton function is also described as one dimension diffusion process by using stochastic average method, the singular boundary theory was taken for analyzing the global stochastic stability of the system, and the systems stochastic stability was researched by solving the Fokker-Planck-Kolmogorov (FPK equation. The results show that the stochastic excitation model obtained has significance for analyzing and researching stochastic dynamics characteristics to the system, and also generalized energy H in the range of 0.02 to 0.4, the systems response has the minimum transition probability density, and the system state is not easy to change, therefore the system generalized energy H should be to limit in this range in the design and operation of the rolling mill.

  13. Optimized simulation of vortex jet mill in waste rubber grinding technology by LNG

    Science.gov (United States)

    Han, Yuemei

    2015-07-01

    Frozen rubber powder has excellent qualities and application value, and it can be achieved from waste rubber after being crushed at low temperature used liquefied natural gas (LNG) as cryogen. Vortex jet mill was the key equipment to further crush the rubber particles which the pressure-air was jet into in the basic LNG technological process. After confirming the structure and size of the jet nozzle, the Height (H) between the nozzle and the bottom of the mill, the incident angle ? and the initial size of the rubber particles were changed then the continuous phase and the track of single particle were optimized in order to gain more excellent crushing effect. The results showed: the jetting gas were spiral rising in the mill and the speed of it was reduced, so the particle was graded by the gas. The impact and collision could reduce the particle diameter and crush them but the result was influenced by the initial size of the particle. The size of the original rubber particles must not be more than 110?m. The simulation was helpful and leading for the experiment.

  14. Milling dynamics. I - Attritor dynamics: Results of a cinematographic study

    Science.gov (United States)

    Rydin, R. W.; Maurice, D.; Courtney, T. H.

    1993-01-01

    The motions of grinding media and powder in an attritor canister were studied by means of filming the agitated charge and frame-by-frame scrutiny of the footage. In conjunction with auxiliary experiments, this permitted semiquantitative analysis of the milling action. In particular, the mill can be divided into several regions characterized by different balances between direct impacts and rolling/sliding of the grinding media. Simple calculations suggest that impacts are more capable of effecting mechanical alloying (MA) than are rolling or sliding events in an attritor. Powder circulation within an operating mill was also investigated. Based on the results and the accompanying analysis, concepts for improved attritor design are presented.

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

    Directory of Open Access Journals (Sweden)

    Yan Gao

    2013-01-01

    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.

  16. Effect of powder milling on mechanical properties of hot-pressed and hot-rolled CuCrNb alloy

    Energy Technology Data Exchange (ETDEWEB)

    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

    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 Cu8 at% Cr4 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.

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

    Scientific Electronic Library Online (English)

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

    2011-07-01

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

  18. Customized maximal-overlap multiwavelet denoising with data-driven group threshold for condition monitoring of rolling mill drivetrain

    Science.gov (United States)

    Chen, Jinglong; Wan, Zhiguo; Pan, Jun; Zi, Yanyang; Wang, Yu; Chen, Binqiang; Sun, Hailiang; Yuan, Jing; He, Zhengjia

    2016-02-01

    Fault identification timely of rolling mill drivetrain is significant for guaranteeing product quality and realizing long-term safe operation. So, condition monitoring system of rolling mill drivetrain is designed and developed. However, because compound fault and weak fault feature information is usually sub-merged in heavy background noise, this task still faces challenge. This paper provides a possibility for fault identification of rolling mills drivetrain by proposing customized maximal-overlap multiwavelet denoising method. The effectiveness of wavelet denoising method mainly relies on the appropriate selections of wavelet base, transform strategy and threshold rule. First, in order to realize exact matching and accurate detection of fault feature, customized multiwavelet basis function is constructed via symmetric lifting scheme and then vibration signal is processed by maximal-overlap multiwavelet transform. Next, based on spatial dependency of multiwavelet transform coefficients, spatial neighboring coefficient data-driven group threshold shrinkage strategy is developed for denoising process by choosing the optimal group length and threshold via the minimum of Stein's Unbiased Risk Estimate. The effectiveness of proposed method is first demonstrated through compound fault identification of reduction gearbox on rolling mill. Then it is applied for weak fault identification of dedusting fan bearing on rolling mill and the results support its feasibility.

  19. Bearing restoration by grinding

    Science.gov (United States)

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

    1976-01-01

    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.

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

    Science.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-02-15

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

  2. 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)

    R. Kocich

    2009-10-01

    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.

  3. Steel balls forming by cross rolling with upsetting

    Directory of Open Access Journals (Sweden)

    Z. Pater

    2013-01-01

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

  4. Evaluation of Health Consequences of Air Pollution Induced by Beam Rolling Mills Factory (Iran

    Directory of Open Access Journals (Sweden)

    Rafiei Masoud

    2014-10-01

    Full Text Available The increases in air pollution over the metropolitan cities are a threat to human health and environment. An attempt has been made to evaluate the health consequences of indoor air pollution induced by Beam Rolling Mills Factory at Ahwaz (Iran. A questionnaire was prepared to obtain information on health of 481 workers, out of which 200 each were selected from exposed and non-exposed category by stratified randomized method. Fisher exact test and chi-square test were used to calculate the values. The study concludes that more than 80% of the workers have high exposure risk to diseases. Analysis of the health impacts reveals that exposed workers are more prone to various diseases as compared to the non-exposed workers. It is also observed that exposure to air pollutants might be the causative factor for various diseases among the smokers but also nonsmoking workers. The analysis also reveals that there is higher relative risk in occupational fatigue and cardio-vascular disease. Further, the study found that percentage of workers having various diseases is much higher in the indoor environment as compared to the outdoor environment

  5. Effect of blade geometry on motion of media particle and grinding characteristics in horizontal type sand mill and development of a new type of blade; Yokogata sand mill ni okeru kakuhan`yoku no kika keijo ga media ryushi no kyodo to funsai tokusei ni oyobosu eikyo to shingatayoku o kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Teshiba, T.; Takao, M.; Komori, S.; Murakami, Y. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Yoshida, H. [Mitsubishi Heavy Indutries, Ltd., Tokyo (Japan)

    1996-07-10

    The motion of grinding media was visualized on three types of blade (normal disk type, hole disk type and cross type) for a horizontal type sand mill of which internal blade and external cylinder rotate inversely and independently. As a result, the effect of blade geometry on velocity distribution, the intensity of velocity fluctuations and appearance frequency of grinding media was made clear. The relationship between these flow characteristics and grinding rate was discussed by carrying out grinding tests of calcium carbonate. As a result, it is found that the grinding characteristics obtained for each blade in both rotation methods can be well correlated with the intensity of velocity fluctuations weighted by appearance frequency. A new type of blade (cross turbine type) was produced based on the above information, and its grinding rate was investigated in connection with the motion of the grinding media. The results showed that it has a higher rate of grinding than the three tides of blades previously used. 9 refs., 11 figs.

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

    Directory of Open Access Journals (Sweden)

    Behzad BahramiNejad

    2015-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Piyas Palit

    2015-04-01

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

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

    Scientific Electronic Library Online (English)

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

    2009-06-01

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

  9. Fabrication of cold-rolled sheet using 1700 mill in Karaganda metallurgical works

    International Nuclear Information System (INIS)

    Technical specifications are presented and the operation experience is summarized of the continuous five-cage cold rolling stand 1700 KarMK put into operation in 1973. The peculiarities of the technology of fabrication of cold-rolled strips of 0.5-2.0 mm thickness are considered. The factors of rolling various thickness and manufactured strips are analyzed, the optimum cogging conditions are recommended. Data on wearing and on changing of microrelief of shaft surface are given. The equipment available and the technology adopted ensure the fabrication of cold-rolled sheet in conformity with the state standard (GOST) requirements

  10. STUDIES ON CONTINUOUS GRINDING PROCESS FOR DRIED WATER CHESTNUT KERNEL

    OpenAIRE

    S K Garg; U.C. LOHANI; PANDEY, J.P.

    2010-01-01

    Grinding is a unit operation to break big solid material into smaller pieces. As far as process of grinding is concerned, power consumption, specific energy consumption and particle size distribution and mill capacity are main considerations from engineering point of view. The experiments were conducted to study the effect of speed of mill, sieve size, feed rate and time of grinding on power consumption and average particle diameter of water chestnut in continuous grinding process. Power cons...

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

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

    International Nuclear Information System (INIS)

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

  14. Using the eight-roller mill in the purifier-less mill flow.

    Science.gov (United States)

    Fistes, Aleksandar; Raki?, Duan

    2015-07-01

    Double grinding of mill streams without intermediate sieving, i.e. the eight-roller milling system provides opportunities for significant reduction of capital cost compared to conventional wheat flour milling system. In this study the effects of using the eight-roller mill in the purifier-less mill flow were investigated. Middlings from the break system of commercial flour mill, which would be sent to the purification system, were intercepted and employed in the experiments. Milling results obtained with double grinding of middlings were compared with the results obtained by conventional system with intermediate sifting before regrinding of stock. At the same roll gap setting and under the same sieving conditions, the eight-roller system produced less flour compared to the conventional system. Results showed that the most efficient way to increase flour yield in the eight-roller milling system is to increase the upper size limit of flour by increasing the sieve aperture. This is not followed by the deterioration of flour quality as determined by ash content. Increase of the upper size limit of flour particles is followed by the decrease of the flour ash content suggesting that it is possible to implement the eight-roller mills in the purifier-less mill flow. PMID:26139941

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, V.S.; Modak, J.P

    2003-04-01

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

  17. Grain refinement of magnesium alloy sheets by ARB using high-speed rolling mill

    International Nuclear Information System (INIS)

    Applications of ARB to magnesium alloys were limited due to low deformability. The authors recently found that the rollability of the alloys is significantly improved in highspeed rolling. It is supposed that the severe plastic deformation of magnesium alloy sheets is feasible if rolling in ARB processes is conducted at high speed. In this study, AZ31B and ZK60A sheets are processed by ARB up to five cycles at 423K with a speed of 1000m/min. Vickers hardness increases with increasing number of ARB cycles, while the tensile strength shows the maximum after the second cycle. The grain size is reduced significantly at the first cycle and decreases gradually from the second cycle. The mean grain sizes after five cycles are 1.6?m for AZ31B and 1.8?m for ZK60A. It is concluded that ARB using high-speed rolling is effective for grain refinement of magnesium alloys.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-07-01

    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.

  19. Effect of rotation method of internal blade and external cylinder on media particles and grinding characteristics in horizontal type sand mill; Yokogata sand mill ni okeru uchihane to sotozutsu no kaiten hoshiki ga media ryushi nokyodo to funsai tokusei ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Teshiba, T.; Takao, M.; Komori, S.; Murakami, Y. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Yoshida, H. [Mitsubishi Heavy Indutries, Ltd., Tokyo (Japan)

    1996-05-10

    A measuring technique to visualize the motion of media particles has been developed for a horizontal type sand mill, in which internal blade and external cylinder rotate inversely and independently. Using this experimental techniques velocity distribution, intensity of velocity fluctuations and appearance frequency of grinding media in the mill chart be measured. Relating to these flow characteristics of media particles for both rotation methods, the grinding performance of calcium carbonate with alumina beads is discussed. As a result, it is found that the median diameter of ground products obtained in both rotation methods can not be correlated only with the intensity of velocity fluctuations having been used to date, but can be correlated well with the intensity of velocity fluctuations weighted by appearance frequency. 7 refs., 11 figs.

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

    Scientific Electronic Library Online (English)

    Ricardo, Floriano; Daniel Rodrigo, Leiva; Stefano, Deledda; Bjrn Christian, Hauback; Walter Jos, Botta.

    2013-02-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-05-01

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

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

    International Nuclear Information System (INIS)

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

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

    Scientific Electronic Library Online (English)

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

    2005-12-01

    Full Text Available Las chumaceras de bronce utilizadas actualmente en los molinos de caa de azcar presentan elevado desgaste debido, entre otros factores, a la materia extraa que ingresa en ella cuando el eje superior se eleva (flota) por efecto del colchn de caa que pasa entre las mazas y al sobrecalentamiento c [...] ausado por fallas en los sistemas de lubricacin y refrigeracin. Con el objetivo de solucionar estos problemas dos diseos de chumaceras fueron realizados: uno con refrigeracin en la caja y otro con refrigeracin en la teja, ambos usando un sistema de sellado. Anlisis por Elementos Finitos del comportamiento mecnico y trmico de los diseos garantiza un buen desempeo en operacin. 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.

  4. Energy Use of Fine Grinding in Mineral Processing

    Science.gov (United States)

    de Bakker, Jan

    2013-12-01

    Fine grinding, to P80 sizes as low as 7 μm, 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.

  5. Possibilities of enhancing the rolling quality in the course of deformation of high-alloy steel ingots on the roughing mill

    International Nuclear Information System (INIS)

    At the Dneprospetsstal' plant the variation in power parameters of rolling, the temperature and plasticity of the metal on deformation of ingots of stainless steels 10Kh23N18, 10Kh17N13M2T, and 12Kh18N10T have been investigated on a 950 mill. Upon combined analysis of the variations in the deformation conditions and the properties of the metal in the course of rolling, one can recommend the ways for improving the quality of the rolled stock and the mill efficiency. In the rolling of 2.8-ton (metric), 540x540 mm ingots, the lowest plasticity , nsub(k) is observed before the pass 15-16 because of the presence of a cast structure in the initial passes and the temperature drop in the subsequent ones. One must reduce compressions in these passes, and increase them in the others. It is also expedient to allow a short overheating (for 15-20 min) of the ingot surface up to 1300 deg C (30-50 deg. above the optimum)

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

    Directory of Open Access Journals (Sweden)

    Fenglan Wang

    2013-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Jeetendra Mohan Khare

    2013-04-01

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

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

    OpenAIRE

    Jeetendra Mohan Khare; Sandip Kumar Mishra; Shashank Shrivastava

    2013-01-01

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

  9. Pitt Mill Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Oder, R.R.; Borzone, L.A.

    1990-05-01

    Results of a technical and economic evaluation of application of the Pitt Mill to fine coal grinding are presented. The Pitt Mill is a vertically oriented, batch operated, intermediate energy density (0. 025 kW/lb media), stirred ball mill. The mill grinds coal from coarse sizes (typically 3/16 inch or 4 mesh topsize) to the 10 micron to 20 micron mean particle diameter size range in a single step using a shallow grinding bed containing inexpensive, readily available, course grinding media. Size reduction is efficient because of rapid product circulation through the grinding bed caused by action of a novel circulation screw mounted on the agitator shaft. When a dispersant is employed, the grinding can be carried out to 50% to 60% solids concentration. Use of coarse grinding media offers the possibility of enhanced mineral liberation because size reduction is achieved more by impact shattering than by attrition. The batch method offers the possibility of very close control over product particle size distribution without overproduction of fines. A two- phase program was carried out. In the first phase, Grinding Studies, tests were run to determine a suitable configuration of the Pitt Mill. Machine design parameters which were studied included screw configuration, media type, agitator RPM, time, media size, and slurry chamber aspect ratio. During the last part of this phase of the program, tests were carried out to compare the results of grinding Pocahontas seam, Pittsburgh {number sign}8, and East Kentucky Mingo County coals by the Pitt Mill and by a two-stage grinding process employing a Netzsch John mill to feed a high energy density (0.05 kW/Lb media) disc mill. 22 refs., 25 tabs.

  10. Longitudinal Grinding of Aspen

    OpenAIRE

    Thapa, Rinez

    2011-01-01

    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. The entire process included longitudinal grinding of aspen. There were five different points at which aspen were cut for longitudinal grinding. The points were at an angle of 00, 150,300,450 and 00 with reference of traditional grinding. For each p...

  11. 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)

    J. Krawczyk

    2008-07-01

    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.

  12. Increasing energy efficiency of grinding media through microscale comminution studies

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Y.C.; Goller, G.A. [GS Technologies/Control International Inc., Salt Lake City, UT (United States)

    1995-12-31

    Microscale studies involving an ultrafast load cell have been shown to provide direct and accurate measurements of particle strength, particle fracture energy and particle breakage functions under different loading geometry conditions. The effect of grinding media size, shape, density and surface properties on the energy efficiency can be quantitatively determined for different materials to be ground. The applications of microscale comminution studies have been demonstrated to provide good predictions of grinding mill performance with different grinding media.

  13. Process for grinding graphite

    Energy Technology Data Exchange (ETDEWEB)

    Junttila, J. D.

    1985-08-06

    Disclosed is a process for grinding graphite comprising: forming a mixture of graphite and a graphite grinding aid; grinding the mixture of graphite and graphite grinding aid to reduce the size of the graphite; forming an aqueous slurry of the graphite particles, graphite grinding aid and water; adding an amount of hydrocarbon oil to the aqueous slurry with agitation to form graphite-oil agglomerates; separating the graphite-oil agglomerates from the grinding aid and water; and removing hydrocarbon oil from the graphite-oil agglomerates to provide graphite particles reduced in size.

  14. Ultra-fine grinding and mechanical activation of mine waste rock using a high-speed stirred mill for mineral carbonation

    Science.gov (United States)

    Li, Jia-jie; Hitch, Michael

    2015-10-01

    CO2 sequestration by mineral carbonation can permanently store CO2 and mitigate climate change. However, the cost and reaction rate of mineral carbonation must be balanced to be viable for industrial applications. In this study, it was attempted to reduce the carbonation costs by using mine waste rock as a feed stock and to enhance the reaction rate using wet mechanical activation as a pre-treatment method. Slurry rheological properties, particle size distribution, specific surface area, crystallinity, and CO2 sequestration reaction efficiency of the initial and mechanically activated mine waste rock and olivine were characterized. The results show that serpentine acts as a catalyst, increasing the slurry yield stress, assisting new surface formation, and hindering the size reduction and structure amorphization. Mechanically activated mine waste rock exhibits a higher carbonation conversion than olivine with equal specific milling energy input. The use of a high-speed stirred mill may render the mineral carbonation suitable for mining industrial practice.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yi-Wen Cheng; Patrick Purtscher

    1999-07-30

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

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

    International Nuclear Information System (INIS)

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

  17. Influence of the charged amount of ball media on grinding speed in wet rotational ball milling; Sisshiki kaiten ball mill no funsai sokudo ni oyobosu ball jutenryo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, K.; Watanabe, H.; Tomino, H.; Kondo, Y. [Kagawa Industrial Tech. Center, Kagawa (Japan)

    1998-07-01

    For preparation method of the ceramics raw materials, number of new methods called build-up method were researched and developed to make possible to prepare powders with high purity and sub-micron size. However, there are a lot of raw materials for ceramics prepared by crashing raw materials synthesized by using solid phase reaction and others even at present. In order to obtain fine powder, as wet type crashing method is adopted and some methods such as vibration ball-mill using balls for crashing media, and medium stirring mill are investigated, wet type rotary ball-mill method used long years ago is adopted as a dominant method. In this research, for crashing of alumina due to the wet type rotary ball-mill method using four kinds of small diameter ball, effect of ball filling and pot rotation number on crashing speed was investigated. As a result, it could be obtained some informations such as possibility of increasing the crashing speed by selecting the ball filling and rotation number, and so forth. 7 refs., 7 figs., 1 tab.

  18. STUDIES ON CONTINUOUS GRINDING PROCESS FOR DRIED WATER CHESTNUT KERNEL

    Directory of Open Access Journals (Sweden)

    S.K. GARG

    2010-06-01

    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.

  19. Effects of grinding on certain crystalline structures

    International Nuclear Information System (INIS)

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

  20. Effect of wet grinding on structural properties of ball clay

    Science.gov (United States)

    Purohit, A.; Hameed, A.; Chander, S.; Nehra, S. P.; Singh, P.; Dhaka, M. S.

    2015-05-01

    In this paper, the effect of wet grinding on structural properties of ball clay is undertaken. The wet grinding treatment was performed employing ball and vibro mills for different time spells of 2, 4, 8 and 16 hours. The structural properties were carried out using X-ray diffraction (XRD). The structure of ground samples is found to be simple cubic. The crystallographic parameters are calculated and slight change in lattice constant, inter planner spacing and particle size is observed with grinding treatment. The results are in agreement with the available literature.

  1. Effect of particle size on performance. 3. Grinding pelleting interactions.

    Science.gov (United States)

    Nir, I; Hillel, R; Ptichi, I; Shefet, G

    1995-05-01

    Three experiments were conducted to study the effect of particle size obtained by grinding wheat and sorghum in a hammer mill (HM) or roller mill (RM) on broiler performance. Broilers were fed a mash diet or crumbles to 4 wk of age, then pellets to 7 wk of age. When fed as a mash, diets produced with RM-ground grain improved performance. The effect of grinding was additive to that of pelleting. The interactive effects observed between grinding method and the form of the feed on body weight and feed intake were explained by the higher response to pelleting when grains were ground in HM vs RM. The positive effect of grinding in RM on feed utilization was found to be additive to that of pelleting in all three experiments. The response of females to feed texture was less pronounced than that of males. In males, feeding pellets vs mash increased mortality due to ascites threefold, whereas grinding method had no effect. Females were less susceptible to ascites than males, and feed texture had no effect in this respect. The effects of grinding and pelleting on the gastrointestinal tract segments were additive. The main effects of feed texture were a significant increase in stomach weight and that of its contents following HM grinding and a decrease in these following pelleting, with no interactions between the two. PMID:7603952

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

    Scientific Electronic Library Online (English)

    P., Rosario; R., Hall.

    2010-03-01

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

  3. STABLE DIAMOND GRINDING

    Directory of Open Access Journals (Sweden)

    Yury Gutsalenko

    2010-06-01

    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.

  4. Influence of Agglomeration and Contamination in the Course of Amorphous Powder Grinding on Structure and Microstructure of Sintered Mullite

    OpenAIRE

    Stanislav KURAJICA; Tkal?ec, Emilija; Matijai?, Gordana; ?urkovi?, Lidija; Schauperl, Zdravko; IPUI?, Juraj; Mandi?, Vilko

    2011-01-01

    The process of grinding of amorphous pre-mullite powder has been investigated. The powder has been obtained by sol-gel process followed by drying, calcination and wet milling in planetary ball mill for various periods. While particle size distributions shifts to finer size distributions as the grinding time increase, the specific surface area dependence on the grinding time shows complex behavior. This was attributed to the agglomeration in the course of calcinations partially pro...

  5. Utilisation of chip thickness models in grinding

    Science.gov (United States)

    Singleton, Roger

    Grinding is now a well established process utilised for both stock removal and finish applications. Although significant research is performed in this field, grinding still experiences problems with burn and high forces which can lead to poor quality components and damage to equipment. This generally occurs in grinding when the process deviates from its safe working conditions. In milling, chip thickness parameters are utilised to predict and maintain process outputs leading to improved control of the process. This thesis looks to further the knowledge of the relationship between chip thickness and the grinding process outputs to provide an increased predictive and maintenance modelling capability. Machining trials were undertaken using different chip thickness parameters to understand how these affect the process outputs. The chip thickness parameters were maintained at different grinding wheel diameters for a constant productivity process to determine the impact of chip thickness at a constant material removal rate.. SIZE: 12pt; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-fareast-language: EN-US; mso-ansi-language: EN-GB; mso-bidi-language: AR-SA">Additional testing using a modified pin on disc test rig was performed to provide further information on process variables. The different chip thickness parameters provide control of different process outputs in the grinding process. These relationships can be described using contact layer theory and heat flux partitioning. The contact layer is defined as the immediate layer beneath the contact arc at the wheel workpiece interface. The size of the layer governs the force experienced during the process. The rate of contact layer removal directly impacts the net power required from the system. It was also found that the specific grinding energy of a process is more dependent on the productivity of a grinding process rather than the value of chip thickness. Changes in chip thickness at constant material removal rate result in microscale changes in the rate of contact layer removal when compared to changes in process productivity. This is a significant piece of information in relation to specific grinding energy where conventional theory states it is primarily dependent on chip thickness..

  6. 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)

  7. Role of abrasion and corrosion in grinding media wear. Volume 1. [Taconite; molybenite

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.J.; Iwasaki, I.

    1986-01-01

    Purpose of this project was to investigate the effect of grinding conditions, e.g., pH, P/sub O/sub 2//, grinding media composition and, in particular, size of mill on the wear rates and wear mechanism for both a molybdenite ore and a magnetic iron ore. This allowed data to be obtained on the correlation of scale-up between small diameter laboratory mills and industrial mills and provided a relatively inexpensive test method to be developed for the selection of grinding media used with different ores. Secondly, the effect of the physico-chemical properties of the slurry on wear mechanism(s) and wear rates was evaluated using various slurry media and additives. Results of this work were aimed at providing information from which a more efficient selection of grinding media and conditions may be made which will reduce the total energy consumed in the grinding of minerals.

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

    Directory of Open Access Journals (Sweden)

    Rafiei Masoud

    2009-01-01

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

  9. 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.

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

    CERN Document Server

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

    2000-01-01

    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...

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

    Science.gov (United States)

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

    2014-10-01

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

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

    OpenAIRE

    COSTEA Claudiu Raul; SILAGHI Helga; KOVENDI Zoltan

    2011-01-01

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

  13. ONLINE SAG MILL PULSE MEASUREMENT AND OPTIMIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Raj Rajamani; Jose Delgadillo; Vishal Duriseti

    2006-06-24

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

  14. Photoacoustic study of nanocrystalline silicon produced by mechanical grinding

    International Nuclear Information System (INIS)

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

  15. Nitramine Drying & Fine Grinding Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Nitramine Drying and Fine Grinding Facility provides TACOM-ARDEC with a state-of-the-art facility capable of drying and grinding high explosives (e.g., RDX and...

  16. 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.

  17. Electro-chemical grinding

    Science.gov (United States)

    Feagans, P. L.

    1972-01-01

    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.

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

    OpenAIRE

    Vijay Gautam

    2013-01-01

    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 equipmen...

  19. Development of database and searching system for tool grinding

    Directory of Open Access Journals (Sweden)

    J.Y. Chen

    2008-02-01

    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.

  20. High Performance Grinding and Advanced Cutting Tools

    CERN Document Server

    Jackson, Mark J

    2013-01-01

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

  1. Grind hardening process

    CERN Document Server

    Salonitis, Konstantinos

    2015-01-01

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

  2. The role of abrasion and corrosion in grinding media wear: Annual technical progress report. [Taconite; molybdenite; quartzite

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.J.; Iwasaki, I.

    1984-06-12

    Aim of this research program is to establish the effect of mill size and batch or continuous operation on the role of corrosive and abrasive wear during mineral grinding operations. Grinding ball wear tests are being conducted on the laboratory, pilot plant and industrial scale. This report gives the results of the first year's work of the two year research program and are discussed under the following headings: Wear Tests in an 8-inch Laboratory Mill (Using Three Different Ball Chemistries for Both Taconite and Molybdenite Ore); Wear Tests in a 36-inch Batch Mill (Using High Carbon Low Alloy Steel Balls with Taconite); Mechanisms of Erosive Wear in Taconite Grinding (Using Mild Steel Balls); The Effect of Slurry Rheology on Grinding Media Wear (Using Mild Steel Balls - Quartzite Combination); and Pilot Plant continuous Grinding Tests (Using High Carbon Low Alloy Steel Balls with Taconite Ore).

  3. Grinding Inside A Toroidal Cavity

    Science.gov (United States)

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

    1987-01-01

    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.

  4. Surface Fine Grinding via a Regenerative Grinding Methodology

    International Nuclear Information System (INIS)

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

  5. Role of abrasion and corrosion in grinding media wear. Volume III

    Energy Technology Data Exchange (ETDEWEB)

    Eggert, J.F.

    1985-01-01

    The relative contributions of abrasion and corrosion and the effect of scale-up on the wear rates of three different grind materials in molybdenite and taconite ore milling under three mill atmospheres was investigated. A standardized marked ball wear test was implemented to obtain reliable and reproducible results from the three mill sizes. The mechanisms responsible for wear were determined through SEM and EDX examinations.

  6. Rolling and annealing texture in twin roll cast commercial purity aluminium

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.)

  7. 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)

    Mengel, J.

    2003-12-16

    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.

  8. Computation of Rolling Stand Parameters by Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Frantiek ?urovsk

    2008-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Vijay Gautam

    2013-10-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Noel Williamson*1

    2014-04-01

    Full Text Available This paper presents the analysis of mechanisms of removal in vibration-assisted grinding process. It is known that generally for machining, application of vibration helps to increase material removal rate, reduces tool wear rate and increases depth of machining. As the failure of a component originates from the surface, effect of assisted grinding is carried out on a milling machine. The machine is equipped with a grinding wheel on which small frequency vibrations are applied. The resultant path of the tool is analytically evaluated. Longitudinal vibrations are developed by using a rotary mechanism. It was demonstrated that there are several favorable effects of vibrations in grinding process including: reduced tool forces, better surface finish and improved tool life. It is observed that the application of vibrations improve the process characteristics in grinding, to a large extent.

  11. Role of abrasion and corrosion in grinding media wear. Volume 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.J.; Iwasaki, I.

    1986-01-01

    Purpose of this project was to investigate the effect of grinding conditions, e.g., pH, P/sub O/sub 2//, grinding media composition and, in particular, size of mill on the wear rates and wear mechanism for both a molybdenite ore and a magnetic iron ore. This allowed data to be obtained on the correlation of scale-up between small diameter laboratory mills and industrial mills and provided a relatively inexpensive test method to be developed for the selection of grinding media used with different ores. Also, the effect of the physico-chemical properties of the slurry on wear mechanism(s) and wear rates was evaluated using various slurry media and additives.

  12. Rolling Stonesi kinokontsert kannab toorest rokivge / Maris Meiessaar

    Index Scriptorium Estoniae

    Meiessaar, Maris

    2009-01-01

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

  13. Milling media from zirconia ceramics

    International Nuclear Information System (INIS)

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

  14. THE CHARACTERIZATION OF GRINDING FORCES

    Directory of Open Access Journals (Sweden)

    E.F. Fielding

    2012-01-01

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

  15. TRISO-coated spent fuel processing using a Grind-Leach head-end

    International Nuclear Information System (INIS)

    Processing of TRISO-coated HTGR fuels with the grind-leach process requires that the fuel be finely pulverized for efficient and effective acid dissolution of the fuel components. Mechanical size reduction of the fuel is being investigated with jet mill technology as the final milling step. Laboratory experiments were performed with surrogates of crushed fuel compacts that indicate that milling to very small particle sizes is feasible. The size distribution of the milled product is sensitive to the solids feed rate, and the distribution may be bimodal which could support an effective solid-solid separation. (author)

  16. Spray rolling aluminum alloy strip

    International Nuclear Information System (INIS)

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

  17. 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)

  18. Role of abrasion and corrosion in grinding media wear. Volume II

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.J.; Iwasaki, I.

    1984-01-01

    The effects of slurry rheological properties on the erosive wear of grinding media and grinding efficiency (percent minus 325 mesh) have been studied in a laboratory ball mill using minus 10 mesh quartzite. A laboratory procedure was also utilized to evaluate the tendency for the slurry to coat the grinding media. Media wear decreased continuously with increasing percent solids while grinding efficiency was maximized at 60% solids. Slurry percent solids were found to be the critical factor affecting media wear in high percent solids slurries while other factors such as viscosity were more important at lower percent solids. This was demonstrated by the use of a grinding aid in a 70% solids slurry which resulted in only a small increase in wear (44 to 45.6 mg/ball) despite a significant reduction in viscosity (2359 mPa S at 75 rpm). Slurry relative viscosity was found to control the thickness of the slurry coating the balls which was in turn related in a direct linear manner to media wear. In terms of percent minus 325 mesh, the effects of viscosity and ball coating were in agreement with those presented in the literature. Scanning electron microscopic evaluation of ball surfaces and visual inspection of the movement of the ball charge both tended to support the theory of grinding in ball mills through nipping more so than attrition.

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

    OpenAIRE

    Niemczyk, Piotr; Bendtsen, Jan Dimon

    2011-01-01

    A novel controller for coal circulation and pulverized coal flow in a coal mill is proposed. The design is based on optimal control theory for bilinear systems with additional integral action. The states are estimated from the grinding power consumption and the amount of coal accumulated in the mill by employing a special variant of a Luenberger observer. The controller uses the rotating classifier to improve the dynamical performance of the overall system. The proposed controller is compared...

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

    DEFF Research Database (Denmark)

    Saleh, Suriyati Binti; Hansen, Brian Brun; Jensen, Peter Arendt; Dam-Johansen, Kim

    2013-01-01

    Combining torrefaction and grinding of biomass in one reactor may be an attractive fuel pretreatment process. A combined laboratory torrefaction and ball mill reactor has been constructed for studies of the influence of temperature and residence time on the product yields and particle size...... of straw for 90 min yielded a higher mass loss (27–60 wt %) and relative size reduction (59–95%) compared with spruce (mass loss of 10–56 wt % and size reduction of 20–60%). The two types of biomass investigated differ with respect to hemicellulose type, lignocellulosic composition, particle...... morphology, and ash composition, where straw has a higher alkali content. This and other studies indicate that the large difference in the alkali contents of the biomasses is the main cause for the observed difference in torrefaction characteristics. Experiments with separate particle heating and grinding...

  1. Online SAG Mill Pluse Measurement and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Raj Rajamani; Jose Delgadillo; Vishal Duriseti

    2007-06-30

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

  2. Optimization of Process Variables for Grinding of Ibuprofen using Response Surface Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Chol-Ho [Sangji University, Wonju (Korea, Republic of)

    2013-12-15

    Ibuprofen, non-steroidal anti-inflammatory drugs; NSAIDs, is a highly crystalline substance with the pharmaceutical properties of poor solubility and low bioavailability. The size reduction of ibuprofen is needed to improve the solubility. The objective of this study is to optimize the grinding condition of ibuprofen. Grinding of ibuprofen was carried out using a planetary mill. Grinding parameters were optimized using Box-Behnken experimental design method. The physical characteristics of ground ibuprofen were investigated for the particle size by particle size analyzer, for the crystal size by X-ray diffraction (XRD), and for the tensile strength by tensile/compression tester. The optimum conditions for the milling of ibuprofen were 290 rpm of the revolution number of mill, 24.6 g of the weight of sample, and 10minutes of grinding time. The measured value of the particle size of ground ibuprofen at these optimum conditions was 13.5 m. The results showed that the crystal size of ibuprofen was reduced by the planetary milling process. In case the relative density of the tablets formulated of ground ibuprofen was range of 0.85-0.90, the tensile strength of them was range of 12-14 Kg{sub f}/cm{sup 2}.

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

    Science.gov (United States)

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

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

    DEFF Research Database (Denmark)

    Saleh, Suriyati Binti; Hansen, Brian Brun

    2013-01-01

    Combining torrefaction and grinding of biomass in one reactor may be an attractive fuel pretreatment process. A combined laboratory torrefaction and ball mill reactor has been constructed for studies of the influence of temperature and residence time on the product yields and particle size reductions of Danish wheat straw, spruce chips, and pine chips. On the basis of initial experiments, which evaluated the influence of reactor mass loading, gas flow, and grinding ball size and material, a standard experimental procedure was developed. The particle size reduction capability of the torrefaction process has been evaluated by the relative change in d50, and this method was compared to the Hardgrove grindability index (HGI), showing reasonably similar results. Significant differences in torrefaction behavior have been observed for straw and spruce chips torrefied at 270330 C. Torrefaction of straw for 90 min yielded a higher mass loss (2760 wt %) and relative size reduction (5995%) compared with spruce (massloss of 1056 wt % and size reduction of 2060%). The two types of biomass investigated differ with respect to hemicellulose type, lignocellulosic composition, particle morphology, and ash composition, where straw has a higher alkali content. This and other studies indicate that the large difference in the alkali contents of the biomasses is the main cause for the observed difference in torrefaction characteristics. Experiments with separate particle heating and grinding showed a swift grinding of the torrefied biomass. This implies that the rate-limiting step in the laboratory reactor is the heat transfer and not the grinding process. Large pine particles (816 mm) showed a slightly higher mass loss than 48 and <4 mm particles. This could be the consequence of exothermic reactions in the particle core, which locally increase the temperature and conversion.

  5. Surface Grinding Machine Stability Characteristics Limited Prediction

    OpenAIRE

    Yuting Yang; Jianzhong Lin; Shilong Xu

    2012-01-01

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

  6. Metal rolling - Asymmetrical rolling process

    Science.gov (United States)

    Alexa, V.; Raţiu, S.; Kiss, I.

    2016-02-01

    The development of theory and practice related to the asymmetric longitudinal rolling process is based on the general theory of metalworking by pressure and symmetric rolling theory, to which a large number of scientists brought their contribution. The rolling of metal materials was a serious problem throughout history, either economically or technically, because the plating technologies enabled the consumption of raw materials (scarce and expensive) to be reduced, while improving the mechanical properties. Knowing the force parameters related to asymmetric rolling leads to the optimization of energy and raw material consumption. This paper presents data on symmetric rolling process, in order to comparatively highlight the particularities of the asymmetric process.

  7. Ceramic-bonded abrasive grinding tools

    Science.gov (United States)

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

    1994-01-01

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

  8. Grinding with classification via geometric partition models

    International Nuclear Information System (INIS)

    A grinding process with classification is considered. An integral grinding equation connecting the final particle size distribution function to the particle size distribution function before the grinding process is studied. Geometric partition models are used to obtain the breakage function. The results are compared with experimental data

  9. Ceramic-bonded abrasive grinding tools

    Science.gov (United States)

    Holcombe, C.E. Jr.; Gorin, A.H.; Seals, R.D.

    1994-11-22

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

  10. Ultrasonic precision optical grinding technology

    Science.gov (United States)

    Cahill, Michael J.; Bechtold, Michael J.; Fess, Edward; Wolfs, Frank L.; Bechtold, Rob

    2015-10-01

    As optical geometries become more precise and complex and a wider range of materials are used, the processes used for manufacturing become more critical. As the preparatory stage for polishing, this is especially true for grinding. Slow processing speeds, accelerated tool wear, and poor surface quality are often detriments in manufacturing glass and hard ceramics. The quality of the ground surface greatly influences the polishing process and the resulting finished product. Through extensive research and development, OptiPro Systems has introduced an ultrasonic assisted grinding technology, OptiSonic, which has numerous advantages over traditional grinding processes. OptiSonic utilizes a custom tool holder designed to produce oscillations in line with the rotating spindle. A newly developed software package called IntelliSonic is integral to this platform. IntelliSonic automatically characterizes the tool and continuously optimizes the output frequency for optimal cutting while in contact with the part. This helps maintain a highly consistent process under changing load conditions for a more accurate surface. Utilizing a wide variety of instruments, test have proven to show a reduction in tool wear and increase in surface quality while allowing processing speeds to be increased. OptiSonic has proven to be an enabling technology to overcome the difficulties seen in grinding of glass and hard optical ceramics. OptiSonic has demonstrated numerous advantages over the standard CNC grinding process. Advantages are evident in reduced tool wear, better surface quality, and reduced cycle times due to increased feed rates. These benefits can be seen over numerous applications within the precision optics industry.

  11. Changes in the properties of coal due to reduction in size in different grinding media. Aenderungen von Kohleneigenschaften durch Zerkleinerungsvorgaenge in unterschiedlichen Mahlmedien

    Energy Technology Data Exchange (ETDEWEB)

    Kammerich, B.

    1988-12-20

    The aim of this work was to examine to what extent the reduction in size of coal in different grinding media (surrounding gases/vapours) is connected with changes in relevant coal properties (strength/resistance to grinding, heat of wetting, saturation loading, calorific value, volatile components, swelling index, swelling etc). The experiments were carried out in a laboratory ball mill made of steel at normal pressure and ambient temperature (20/sup 0/C). The type of coal (1 anthracite, 1 coking coal, 1 gas coal, 2 gas flame coals, 1 flame coal), the grinding medium (air, nitrogen, carbon dioxide, ethanol vapour and methanol vapour) and the duration of grinding (between 15 and 90 minutes) were varied. In addition, some grinding experiments were carried out in a disk mill under an atmosphere of air. The results are discussed with regard to the processes for which the coal is used. (RB).

  12. Surface grinding of intermetallic titanium aluminides

    CERN Document Server

    Grning, Holger Andreas

    2014-01-01

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

  13. Fused silica fine grinding with low roughness

    Science.gov (United States)

    Dai, Lei; Gu, Yongqiang; Wu, Di

    2014-08-01

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

  14. Force characteristics in continuous path controlled crankpin grinding

    Science.gov (United States)

    Zhang, Manchao; Yao, Zhenqiang

    2015-03-01

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

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

    OpenAIRE

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

    2014-01-01

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

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

    International Nuclear Information System (INIS)

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

  17. Nanozeolite Produced by Wet Milling at Different Milling Time

    Science.gov (United States)

    Mukhtar, N. Z. F.; Borhan, M. Z.; Abdullah, S.; Rusop, M.

    2013-06-01

    Recently, there has been a considerable growing interest in utilizing nanozeolites due to their advantages over conventional micron sized materials. Zeolite particle may be reduced by mechanical treatment such as ball milling or grinding in order to get smaller particles. In this paper, effect of milling time on particle size and surface morphology of Zeolite were investigated by a few designed of experiments in aqueous environment. Zeta-sizer Nano series of particle sizer and Field Emission Scanning Electron Microscopy (FESEM) have been used to characterize this nanozeolite. Results shown that, there were changes of particle size and also the surface morphology of Zeolite.

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

    Science.gov (United States)

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

    2005-09-27

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

  19. Surface grinding characteristics of ferrous metals under high-speed and speed-stroke grinding conditions

    International Nuclear Information System (INIS)

    Some ferrous metals have been ground under different conditions with high-speed and speed-stroke in surface grinding operation. The paper describes experimental investigation of grinding forces in grinding some ferrous metals with the application of cutting fluids. Grinding tests have been carried out on mild steel, assab steel and stainless steel with different combinations of down feed and cross feed. The wheel speed was 27 m/sec while the table speed was maintained at the maximum possible 25 m/min. The grindability has been evaluated by measuring the grinding forces, grinding ratio, and surface finish. Grinding forces have been plotted against down feed of the grinding wheel and cross feed of the table. It has been observed that the radial and tangential grinding forces in stainless steel were higher than those in assab steel and mild steel

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

    International Nuclear Information System (INIS)

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

  1. Enhanced dissolution and bioavailability of raloxifene hydrochloride by co-grinding with different superdisintegrants.

    Science.gov (United States)

    Jagadish, Balasubramaniam; Yelchuri, Rajesh; K, Bindu; Tangi, Hemalatha; Maroju, Swetha; Rao, Vinay Umesh

    2010-03-01

    The present study investigated the effect of co-grinding raloxifene HCL (RHCL) with different superdisintegrants, namely crospovidone (CP), croscarmellose sodium (CCS) and sodium starch glycolate (SSG), using a ball mill, in order to determine the potential effect on dissolution rate and bioavailability of raloxifene hydrochloride (RHCL). The dissolution studies of the co-ground compositions and the corresponding physical mixtures were carried out in U.S. Pharmacopeia (USP) Type II apparatus. The solid state interactions of the co-ground and the physical mixtures were evaluated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The pharmacokinetics of co-ground mixture (1 : 5 RHCL : CP) and milled RHCL was evaluated following oral administration (25 mg/kg) in healthy female Sprague-Dawley rats. DSC studies showed that the crystalline nature of RHCL was reduced after co-grinding with superdisintegrants, while co-grinding with CP resulted in significant particle-size reduction of the mixture. Significant enhancement in dissolution rate was observed with co-ground mixture of RHCL with CP (1 : 5). The extent of the mean plasma exposures of RHCL was 7-fold higher in animals treated with co-ground mixture of RHCL, CP (1 : 5) compared to animals treated with milled RHCL. Co-grinding of RHCL with CP, reduced drug crystallinity, increased the rate and extent of dissolution, and improved bioavailability. PMID:20190431

  2. Spray Rolling Aluminum Strip for Transportation Applications

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-02-01

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

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

    International Nuclear Information System (INIS)

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

  4. Maximizing wear resistance of balls for grinding of coal

    Energy Technology Data Exchange (ETDEWEB)

    Eduardo Albertin; Sandra Lucia de Moraes [Technological Research Institute (IPT) of the State of Sao Paulo, Sao Paulo (Brazil)

    2007-09-15

    A Brazilian power plant consumes mineral coal with high ash contents to feed four turbines to generate 450 MW. Four ball mills, 4.2 m in diameter, are fed with crushed coal to deliver the material ground to sizes less than 0.075 {mu}m. High wear rates were observed when using forged high-carbon steel balls. A pilot-plant ball mill, with a 0.01 m{sup 3} chamber, was used to perform wear tests, comparing the original ball material and seven grades of high chromium cast irons, grinding the same coal as used in the industrial plant. Test pieces were 60-mm balls with different chemical compositions and heat treatments. Balls were weighed after 10-h grinding periods, for up to 7 periods. The mass losses were converted to equivalent diameter losses and regression straight lines were obtained, showing the wear rates of the materials. The wear rates of the cast irons with 25-30% Cr were only 10-20% of the wear rate of the forged steel. Cast irons with 15-18% Cr wore at around 50% of the rate of the steel. Analyses of the coal ashes showed around 40% of quartz as 10-20 {mu}m particles. Examination of the surface of worn balls showed that these particles caused the wear.

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

    Directory of Open Access Journals (Sweden)

    tevulov Nadeda

    2002-06-01

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

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

    Science.gov (United States)

    Nadolny, Krzysztof

    2012-09-01

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

  7. Grinding tool optimization in computer controlled grinding of SiC aspheric mirror

    Science.gov (United States)

    Song, Ci; Lu, Yi; Peng, Yanglin

    2014-11-01

    The shape, size and material of grinding tool not only affect the machining accuracy, but also the machining efficiency in the process of Computer Controlled Grinding. The hardness of the SiC aspheric mirror, the misfit of grinding tool and the work-piece also emphasize the importance of grinding tool optimization. By means of analyzing the misfit property of grinding tool and aspheric optic theoretically, as well as the wear character and the process of the grinding tool experimentally, this manuscript establishes the rule of grinding tool optimization satisfying different machining objective. Based on this, the adopted grinding tool was optimized in the grinding process of SiC off-axis aspheric (634mm560mm). The simulation provide reasonable grinding tool for the off-axis aspheric grinding, and good results (large amount material removal and edge error figuring) are obtained when the optimized grinding tool are applied. Both of the simulations and experiments demonstrate the feasibility and correctness of the grinding tool optimization method.

  8. The Effects of Wear upon the Axial Profile of a Grinding Wheel in the Construction of Innovative Grinding Wheels for Internal Cylindrical Grinding

    OpenAIRE

    B. S?owi?ski; K. Nadolny

    2011-01-01

    The article describes the effects of wear upon the axial profile of a grinding wheel in the axial cylindrical grinding processes. This mechanism was used to develop a grinding wheel with zone diversified structure made of microcrystalline sintered corundum abrasive grains and vitrifies bond. Such a grinding wheel is characterized by the conical rough grinding zone that is made by grains of a relatively large size, and a cylindrical finish grinding zone with grains of a smaller size and can be...

  9. Rolling Stonesi kinokontsert kannab toorest rokiväge / Maris Meiessaar

    Index Scriptorium Estoniae

    Meiessaar, Maris

    2009-01-01

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

  10. 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

  11. Specific grinding energy and surface roughness of nanoparticle jet minimum quantity lubrication in grinding

    Directory of Open Access Journals (Sweden)

    Zhang Dongkun

    2015-04-01

    Full Text Available Nanoparticles with the anti-wear and friction reducing features were applied as cooling lubricant in the grinding fluid. Dry grinding, flood grinding, minimal quantity of lubrication (MQL, and nanoparticle jet MQL were used in the grinding experiments. The specific grinding energy of dry grinding, flood grinding and MQL were 84, 29.8, 45.5 J/mm3, respectively. The specific grinding energy significantly decreased to 32.7 J/mm3 in nanoparticle MQL. Compared with dry grinding, the surface roughness values of flood grinding, MQL, and nanoparticle jet MQL were significantly reduced with the surface topography profile values reduced by 11%, 2.5%, and 10%, respectively, and the ten point height of microcosmic unflatness values reduced by 1.5%, 0.5%, and 1.3%, respectively. These results verified the satisfactory lubrication effects of nanoparticle MQL. MoS2, carbon nanotube (CNT, and ZrO2 nanoparticles were also added in the grinding fluid of nanoparticle jet MQL to analyze their grinding surface lubrication effects. The specific grinding energy of MoS2 nanoparticle was only 32.7 J/mm3, which was 8.22% and 10.39% lower than those of the other two nanoparticles. Moreover, the surface roughness of workpiece was also smaller with MoS2 nanoparticle, which indicated its remarkable lubrication effects. Furthermore, the role of MoS2 particles in the grinding surface lubrication at different nanoparticle volume concentrations was analyzed. MoS2 volume concentrations of 1%, 2%, and 3% were used. Experimental results revealed that the specific grinding energy and the workpiece surface roughness initially increased and then decreased as MoS2 nanoparticle volume concentration increased. Satisfactory grinding surface lubrication effects were obtained with 2% MoS2 nanoparticle volume concentration.

  12. The analysis of the asymmetric plate rolling process

    Directory of Open Access Journals (Sweden)

    A. Kawa?ek

    2007-08-01

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

  13. Analysis of the bimetallic bars rolling during a skew rolling

    Directory of Open Access Journals (Sweden)

    S. Sawicki

    2008-07-01

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

  14. Manufacturing processes 2 grinding, honing, lapping

    CERN Document Server

    Klocke, Fritz

    2009-01-01

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

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

    OpenAIRE

    Fite Aleksandar Z.; Raki? Duan Z.; Pajin Biljana S.; Doki? Ljubica P.; Nikoli? Ivana R.

    2013-01-01

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

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

    DEFF Research Database (Denmark)

    Niemczyk, Piotr; Bendtsen, Jan Dimon

    2011-01-01

    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.......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...

  17. Precision diamond grinding of ceramics and glass

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-12-01

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

  18. Diamond-Bronze Coatings for Grinding Applications

    Science.gov (United States)

    Tillmann, W.; Vogli, E.; Nebel, J.

    2008-12-01

    Grinding applications for the machining of stone and concrete require composite tools where large diamonds are perfectly embedded into a metallic matrix. With the detonation flame spraying process, it is possible to manufacture these super abrasive composites. Excellent embedment of the voluminous super abrasive particles into the matrix coating material can be realized to produce high quality composite layers for grinding applications of stone and concrete. In this paper, different diamond gradings as well as different volume contents of diamond in matrix are compared. Especially, the influence of particle size on its implantation efficiency is investigated and the influence of process and substrate temperature is analyzed. The thermal sprayed grinding tools are evaluated with respect to their microstructure as well as their grinding abilities. Compared to sintered diamond-bronze samples, the results of an adaptively designed grinding test for the machining of concrete are presented and analyzed.

  19. A study of ball milling of powdered nuclear oxides

    International Nuclear Information System (INIS)

    The nuclear fuel named MOX, Mixed Oxide Fuels, composed of about 3% to 10% of plutonium oxide in uranium allows to recycle plutonium in Pressurized Water Reactors Fuel performances and recycling are strongly connected with the homogeneity of the (U, Pu)O2 solid solution. Because of the low U and Pu cations interdiffusion during sintering, the quality of the mixing of the uranium and plutonium oxides powders obtained by dry ball milling conditions the homogeneity of the MOX fuel. This study contributes to a better understanding of this key step of the fuel fabrication process. The first part of this work deals with the objectives of the study, that is the maximum PuO2 and UO2 particles sizes that are acceptable after the milling operation as far as they will be resorbed by sintering. The second part investigates the micronizing of powders. The grinding mechanisms involved in the ball mill and their effect on the fragmentation of each single powder are analyzed. The third part concludes with the examination of the grinding/mixing of UO2 + CeO2 powders (cerium oxide powder simulates plutonium oxide) with the adjustment of a characterization technique on green pellets of the co-milled mix. This technique allows to evaluate the efficiency of the grinding/mixing by quantifying CeO2 particles size and their distribution in the mix as a function of grinding time, media size and rotational speed on the ball mill. Even with the most severe grinding conditions (increase of rotational speed or decrease of media size), a number of UO2 particles of size larger than the critical size acceptable after the grinding operation still persists. In contrast, from 2 h of grinding, the corresponding fraction associated with CeO2 particles does not exist. Therefore the penalizing parameter for the homogenization is not the PuO2 (CeO2) particles size, but rather that of UO2 aggregates. (author)

  20. Grinding induced martensite on the surface of rails

    DEFF Research Database (Denmark)

    Rasmussen, C.J.; Zhang, Xiaodan

    2014-01-01

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

  1. En route to a multi-model scheme for clinker comminution with chemical grinding aids

    CERN Document Server

    Mishra, R K; Carmona, H A; Wittel, F K; Sawley, M L; Weibel, M; Gallucci, E; Herrmann, H J; Heinz, H; Flatt, R J

    2015-01-01

    We present a multi-model simulation approach, targeted at understanding the behavior of comminution and the effect of grinding aids (GAs) in industrial cement mills. On the atomistic scale we use Molecular Dynamics (MD) simulations with validated force field models to quantify elastic and structural properties, cleavage energies as well as the organic interactions with mineral surfaces. Simulations based on the Discrete Element Method (DEM) are used to integrate the information gained from MD simulations into the clinker particle behavior at larger scales. Computed impact energy distributions from DEM mill simulations can serve as a link between large-scale industrial and laboratory sized mills. They also provide the required input for particle impact fragmentation models. Such a multi-scale, multi-model methodology paves the way for a structured approach to the design of chemical additives aimed at improving mill performance.

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

    International Nuclear Information System (INIS)

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

  3. Progress in abrasive and grinding technology

    CERN Document Server

    Xu, Xipeng

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    D. Urbaniak

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Silva Eraldo Jannone da

    2002-01-01

    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.

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

    Scientific Electronic Library Online (English)

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

    2002-06-01

    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 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.

  7. 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.

  8. High-speed milling of light metals

    Directory of Open Access Journals (Sweden)

    F. Cus

    2007-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ronaldo Yoshinobu Fusse

    2004-09-01

    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.

  10. Separation of P Phase and Fe Phase in High Phosphorus Oolitic Iron Ore by Ultrafine Grinding and Gaseous Reduction in a Rotary Furnace

    Science.gov (United States)

    Gao, Jintao; Guo, Lei; Guo, Zhancheng

    2015-10-01

    Due to the oolitic structure of the high phosphorus iron ore and the closely wrapping of apatite and hematite phases, an approach using jet mill was utilized to grind the ore to ultrafine 0.01 to 0.001 mm, which realizes the dissociation of apatite phase and hematite phase. Then in a laboratory scale rotary furnace, high phosphorus ores of different sizes were reduced by reducing gas at sub-melting point temperatures (973 to 1173 K [700 to 900 C]). In the rotating inclined reactor, the ore particles reacted with the reducing gas coming from the opposite direction in a rolling and discrete state, which greatly improved the kinetic conditions. In this study, the reaction rate increases significantly with the decrease of particle size. For the ultrafine high phosphorus iron ores, the metallization ratio can reach 83.91 to 97.32 pct, but only 33.24 to 40.22 pct for powders with the size of 0.13 to 0.15 mm. The reduced particles maintained their original sizes, without the presence of sintering phenomenon or iron whisker. Hence, two kinds of products were easily obtained by magnetic separation: the iron product with 91.42 wt pct of Fe and 0.19 wt pct of P, and the gangue product with 13.77 wt pct of Fe and 2.32 wt pct of P.

  11. Effects of dry grinding on pyrolliphyte

    OpenAIRE

    Prez Rodrguez, Jos Luis; Madrid, Luis; Snchez-Soto, Pedro Jos

    1988-01-01

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

  12. 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)

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

    Scientific Electronic Library Online (English)

    C.J., Greet.

    2009-01-01

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

  14. DRY AND WET GRINDING KINETICS OF CHROMIUM ORE AND EFFECT OF PULP DENSITY

    Directory of Open Access Journals (Sweden)

    Alper ZKAN

    2006-01-01

    Full Text Available In this study, the kinetics of dry and wet grinding of various feed sizes of chromium ore has been determined using a laboratory scale ceramic ball mill. In addition, the effect of pulp density on the spesific rate of breakage (Si and net production rate to finer than specified size were investigated. The dry and wet grinding of all the size intervals of chromium ore followed the first-order breakage law, and the Si values increased as the feed sizes became coarser. Moreover, the wet grinding of these various feed sizes gave higher Si values by a factor of 2.0 to 2.6 comparing to the dry Si values. From the experimental studies performed on the effect of pulp density on the grinding process, the highest Si value was obtained at a pulp density of 45 % solids by volume. At the same pulp density value, the rate of net production of -75 m particle size also reached the highest value.

  15. 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)

  16. Kinematics of rolling-cutter bit with offset rolling-cutter axes

    Energy Technology Data Exchange (ETDEWEB)

    Abdullin, M.M.; Trushkin, B.N.; Spivak, A.I.

    1981-11-01

    Results of test-bench investigations of kinematic parameters of operation of the equipment of the serially produced rolling-cutter bit, Sh215 9S-GV, are presented. They made it possible to record the mean and ''instantaneous'' frequencies of rotation of milling cutters for any frequency of rotation of the bit. The effect of the bit load on the mean gear ratios of the rolling cutters is established. The degree of nonuniformity of rotation of rolling cutters is shown and a relation is found between the position of teeth of the peripheral rolling cutter rings with respect to the bottom hole and the character of variation of the ''instantaneous'' rolling-cutter gear ratios.

  17. Transverse cylindrical grinding of a eutectic alloy

    Scientific Electronic Library Online (English)

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

    2003-03-01

    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, 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.

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

    OpenAIRE

    ROMAN, N.; E. Ceanga; BIVOL, I.; CARAMAN, S.

    2010-01-01

    The paper tackles with thickness control structure of the cold rolled strips. This structure is based on the rolls position control of a reversible quarto rolling mill. The main feature of the system proposed in the paper consists in the compensation of the errors introduced by the deficient dynamics of the hydraulic servo-system used for the rolls positioning, by means of a dynamic compensator that approximates the inverse system of the servo-system. Because the servo-system is considered va...

  19. Microwave-assisted grinding of metallurgical coke

    International Nuclear Information System (INIS)

    Metallurgical cokes are composed of graphitic carbon (s2p2) and different inorganic compounds with very different capacities to absorb microwave radiation. Moreover, due to the electric conductivity shown by the metallurgical cokes, microwave radiation produces electric arcs or microplasmas, which gives rise to hot spots. Therefore, when these cokes are irradiated with microwaves some parts of the particle experiment a rapid heating, while some others do not heat at all. As a result of the different expansion and stress caused by thermal the shock, small cracks and micro-fissures are produced in the particle. The weakening of the coke particles, and therefore an improvement of its grind ability, is produced. This paper studies the microwave-assisted grinding of metallurgical coke and evaluates the grinding improvement and energy saving. (Author)

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

    OpenAIRE

    M. Drobne; Vuherer, T.; I. Samardi?; S Glode

    2014-01-01

    Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for rolls 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...

  1. Twyman effect mechanics in grinding and microgrinding.

    Science.gov (United States)

    Lambropoulos, J C; Xu, S; Fang, T; Golini, D

    1996-10-01

    In the Twyman effect (1905), when one side of a thin plate with both sides polished is ground, the plate bends: The ground side becomes convex and is in a state of compressive residual stress, described in terms of force per unit length (Newtons per meter) induced by grinding, the stress (Newtons per square meter) induced by grinding, and the depth of the compressive layer (micrometers). We describe and correlate experiments on optical glasses from the literature in conditions of loose abrasive grinding (lapping at fixed nominal pressure, with abrasives 4-400 ?m in size) and deterministic microgrinding experiments (at a fixed infeed rate) conducted at the Center for Optics Manufacturing with bound diamond abrasive tools (with a diamond size of 3-40 ?m, embedded in metallic bond) and loose abrasive microgrinding (abrasives of less than 3 ?m in size). In brittle grinding conditions, the grinding force and the depth of the compressive layer correlate well with glass mechanical properties describing the fracture process, such as indentation crack size. The maximum surface residual compressive stress decreases, and the depth of the compressive layer increases with increasing abrasive size. In lapping conditions the depth of the abrasive grain penetration into the glass surface scales with the surface roughness, and both are determined primarily by glass hardness and secondarily by Young's modulus for various abrasive sizes and coolants. In the limit of small abrasive size (ductile-mode grinding), the maximum surface compressive stress achieved is near the yield stress of the glass, in agreement with finite-element simulations of indentation in elastic-plastic solids. PMID:21127579

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

    Science.gov (United States)

    Wagener, Philipp; Lau, Marcus; Breitung-Faes, Sandra; Kwade, Arno; Barcikowski, Stephan

    2012-09-01

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

  3. MECHANICAL DISINTEGRATION OF WHEAT STRAW BY ROLLER-PLATE GRIND SYSTEM WITH SHARP-EDGED SEGMENTS

    Directory of Open Access Journals (Sweden)

    Lukas Kratky

    2015-04-01

    Full Text Available Colloid mills and extruders are widely used for disintegrating wet fibrous biomass. However, their main disadvantages are a high energy requirement in the range of hundreds or thousands of kWh per ton of material, and the fact that they grind in process cycles. Efforts have therefore been made to design a new type of continuously operated grinder. Its disintegration principle uses a roller-plate grinding system with sharp-edged segments, where the compressive and shear forces combine to comminute the particles. Test experiments verified that the grinder disintegrates wet untreated straw to particles below 10mm in an effective manner in a single pass, with an energy requirement of 50 kWht?1 TS. A 23% increase in biogas yield was achieved, leading to a net gain in electric energy of310 kWht?1 TS.

  4. Analysis on the grinding quality of palm oil fibers by using combined grinding equipment

    Science.gov (United States)

    Gan, H. L.; Gan, L. M.; Law, H. C.

    2015-12-01

    As known, Malaysia is the second largest palm oil producer worldwide after Indonesia, therefore indicating the abundance of its wastes within the country. The plantation would be seen to increase to at least 5.2 million ha by 2020, and the waste generation would be 50-70 times the plantation. However, the efficiency of bulk density is reduced. This is one of the main reasons of the initiation of this size reduction/ grinding research. With appropriate parameters, grinding will be seen to be helping in enhancing the inter-particle bindings, subsequently increasing the quality of final products. This paper focuses on the grinding quality involving palm oil wastes by using the Scanning Electron Microscope (SEM). The samples would first be ground to powder at varying grinding speed and finally got the randomly chosen particles measured to obtain the size range. The grinding speed was manipulated from 15 Hz to 40 Hz. From the data obtained, it was found the particles fineness increased with increasing grinding speed. In general, the size ranged from 45 μm to about 600 μm, where the finest was recorded at the speed of 40 Hz. It was also found that the binding was not so encouraging at very low speeds. Therefore, the optimum grinding speed for oil palm residues lied in the range of 25 Hz to 30 Hz. However, there were still limitations to be overcome if the accuracy of the image clarity is to be enhanced.

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

    Science.gov (United States)

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

    2013-12-01

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

  6. Surface integrity of GH4169 affected by cantilever finish grinding and the application in aero-engine blades

    Directory of Open Access Journals (Sweden)

    Li Xun

    2015-10-01

    Full Text Available GH4169 is the main material for aero-engine blades and integrated blisks. Because GH4169 has a poor milling performance, the profile precision and surface integrity of blades and integrated blisks are difficult to be met by utilizing the conventional milling process, which directly influence the global performance and reliability of aero-engines. Through grinding experiments on parameters and surface integrity optimization, the helical cantilever grinding process utilizing a 300# CBN RB wheel is presented and applied in finish machining of GH4169 blades. The profile errors of the blade surface are within 0.01mm, the roughness is less than 0.4?m, the residual compressive stresses and the hardening rate are appropriate, there are no phenomena of burr and smearing with the grinding chips, and the leading/trailing edge can be smoothly connected with the suction/pressure surface. All the experimental results indicate that this grinding process is greatly suitable for the profile finish machining of GH4169 blades.

  7. The flexible grinding technology based on the electric current control

    Science.gov (United States)

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

    2012-01-01

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

  8. Energy requirement for fine grinding of torrefied wood

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-15

    The purpose of this study is to investigate the influence of torrefaction on wood grinding energy. Wood chips were torrefied at different temperatures and durations. The energy required to obtain fine powder was measured. Particle size analyses were carried out on each powder sample. It is showed that torrefaction decreases both grinding energy and particle size distribution. A criterion to compare grindability of natural and torrefied wood is proposed. It takes into account both grinding energy and particle size distribution. It accounts the energy required for grinding particles to sizes inferior to 200 {mu}m, for given grinding conditions. Torrefaction is characterised by the anhydrous weight loss (AWL) of wood. For AWL inferior to around 8%, grinding energy decreases fast. Over 8%, grinding energy decreases at a slow rate. Particle size distribution decreases linearly as the AWL increases. Both for spruce and beech, the grinding criterion is decreased of 93% when the AWL is around 28%. (author)

  9. KINEMATICS OF MATERIAL REMOVAL AND FORMING OF SURFACE AT GRINDING

    Directory of Open Access Journals (Sweden)

    Feodor NOVIKOV

    2013-05-01

    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

  10. Bruxism (Teeth Grinding or Clenching) (For Parents)

    Science.gov (United States)

    ... teacher). Even arguing with parents and siblings can cause enough stress to prompt teeth grinding or jaw clenching. Some kids who are hyperactive also have bruxism. And sometimes kids with other medical conditions (such as cerebral palsy) or who take certain medicines can develop bruxism. ...

  11. Physicochemical and grinding characteristics of dragonhead seeds

    Science.gov (United States)

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

    2013-12-01

    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.

  12. Precision replenishable grinding tool and manufacturing process

    Science.gov (United States)

    Makowiecki, D.M.; Kerns, J.A.; Blaedel, K.L.; Colella, N.J.; Davis, P.J.; Juntz, R.S.

    1998-06-09

    A reusable grinding tool consisting of a replaceable single layer of abrasive particles intimately bonded to a precisely configured tool substrate, and a process for manufacturing the grinding tool are disclosed. The tool substrate may be ceramic or metal and the abrasive particles are preferably diamond, but may be cubic boron nitride. The manufacturing process involves: coating a configured tool substrate with layers of metals, such as titanium, copper and titanium, by physical vapor deposition (PVD); applying the abrasive particles to the coated surface by a slurry technique; and brazing the abrasive particles to the tool substrate by alloying the metal layers. The precision control of the composition and thickness of the metal layers enables the bonding of a single layer or several layers of micron size abrasive particles to the tool surface. By the incorporation of an easily dissolved metal layer in the composition such allows the removal and replacement of the abrasive particles, thereby providing a process for replenishing a precisely machined grinding tool with fine abrasive particles, thus greatly reducing costs as compared to replacing expensive grinding tools. 11 figs.

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

    Science.gov (United States)

    Gorelova, S.; Schaeben, H.

    2015-04-01

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

  14. GEOMETRICAL CHARACTERIZATION OF MICRO END MILLING TOOLS

    DEFF Research Database (Denmark)

    Borsetto, Francesca; Bariani, Paolo

    2004-01-01

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

  15. 30 CFR 57.14115 - Stationary grinding machines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines. 57.14115 Section... and Equipment Safety Devices and Maintenance Requirements 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with (a) Peripheral...

  16. 30 CFR 75.1723 - Stationary grinding machines; protective devices.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines; protective devices. 75.1723 Section 75.1723 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF....1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other...

  17. 30 CFR 77.401 - Stationary grinding machines; protective devices.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines; protective... OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment 77.401 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit grinders shall be equipped...

  18. Rolling-Element Bearings

    Science.gov (United States)

    Hamrock, B. J.; Anderson, W. J.

    1983-01-01

    Rolling element bearings are a precision, yet simple, machine element of great utility. A brief history of rolling element bearings is reviewed and the type of rolling element bearings, their geometry and kinematics, as well as the materials they are made from and the manufacturing processes they involve are described. Unloaded and unlubricated rolling element bearings, loaded but unlubricated rolling element bearings and loaded and lubricated rolling element bearings are considered. The recognition and understanding of elastohydrodynamic lubrication covered, represents one of the major development in rolling element bearings.

  19. Research on high precision centering assembly method of roll edge optical elements

    Science.gov (United States)

    Liu, Hua; Liu, Xiaomei

    2015-08-01

    In order to improve the imaging quality of target imaging optical system, in the special environment of large temperature difference, the centering assembly precision of roll edge optical elements was studied. According to the hole-axis coordinate error theory of mechanics, by analyzing the factors affected the precision of mechanical heating surface, combining with the existing method to eliminate error and centering assembly process, a new kind of high precision centering assembly method was put forward. Using additional grinding device to grinding roll edge of optical element, eliminate the machining error on the surface of the mechanical hot working, thus improve the centering assembly precision between the roll edge optical element and lens tube. The result of experiment shows that the centering precision can reach less than 3?m when assembled optical element after roll edge using new centering assembly method, and improved by 25% compared to the traditional method of roll edge optical elements are assembled directly after hot working. New assembly method with additional grinding device can improve the centering assembly precision of roll edge optical elements, and greatly reduce the difficulty of optical design of such optical imaging system using in large temperature difference environment, when meet the same image quality.

  20. NORMAL PRESSURE AND FRICTION STRESS MEASUREMENT IN ROLLING PROCESSES

    DEFF Research Database (Denmark)

    Henningsen, Poul; Arentoft, Mogens; Lagergren, Jonas; Jonsson, Nils-Gran; Presz, W.

    2005-01-01

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

  1. Rolling Process Modeling Report. Finite-Element Model Validation and Parametric Study on various Rolling Process parameters

    International Nuclear Information System (INIS)

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

  2. Rolling Process Modeling Report. Finite-Element Model Validation and Parametric Study on various Rolling Process parameters

    Energy Technology Data Exchange (ETDEWEB)

    Soulami, Ayoub [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Paxton, Dean M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burkes, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-06-15

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

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

    Scientific Electronic Library Online (English)

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

    2012-07-01

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

  4. Mathematical Aspect for Worm Grinding Using a Toroidal Tool

    Directory of Open Access Journals (Sweden)

    Tareq A. Abu Shreehah

    2004-01-01

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

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

    DEFF Research Database (Denmark)

    Lagergren, J.; Wanheim, Tarras; Precz, W.; Henningsen, Poul; Arentoft, Mogens; Jonsson, N.G.

    2006-01-01

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

  6. Development of dissimilar metal transition joint by hot bond rolling

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

    Lagergren, Jonas; Wanheim, Tarras; Presz, W.; Henningsen, Poul; Arentoft, Mogens; Jonsson, Nils-Gran

    2005-01-01

    Background/purpose The only way to establish the true rolling pressure and the true friction condition in cold rolling is to conduct measurements in the roll bite. A new transducer design is therefore proposed, this to overcome problems in previous measurements in the past 70 years. Method The new...... stainless steel strips in a pilot mill. The recordings were selected from a steady state with no disturbance from the material flow. The transducer was able to simultaneously measure both the normal pressure and the friction stress. An estimation of the coefficient of friction was accordingly performed....... Conclusions The new transducer works very well, it was seen to be robust and able to avoid signal disturbance. The pressure and friction stress distribution results was as expected by the authors and a good reproducibility, together with a proven agreement between recorded signals and signals simulated...

  8. Mechanochemical Effect in ZnTe Powder Associated with Grinding

    Science.gov (United States)

    Takeuchi, Manabu

    1983-03-01

    Single crystalline ZnTe powder was mechanically ground in air using an agate mortar and pestle, and changes in the structural and photoconductive properties were studied. The mean particle size was reduced to about 5 ?m in the early stage of grinding. In the X-ray diffraction patterns, Te and ZnO lines appeared as 5 h and 8 h grindings, respectively. However, all the diffraction lines disappeared after 50 h grinding. Dark current in the ground ZnTe powder becomes maximum around 8 h grinding. This can be explained by the separation of Te associated with grinding. The original ZnTe powder showed photoconductive sensitivity to visible light. The sensitivity increased slightly in the early stage of grinding and then decreased with further grinding. Temperature dependences of the dark currents were measured in the temperature range of 170-370 K.

  9. Generation of wear during the production of drug nanosuspensions by wet media milling.

    Science.gov (United States)

    Juhnke, Michael; Mrtin, Dirk; John, Edgar

    2012-05-01

    Wet media milling is an established technique for the commercialized top-down production of nanoparticulate drug suspensions. These drug nanosuspensions can be transferred into the related drug products, like capsules, tablets and injectables. The generation of wear during stirred media milling of a drug compound was investigated for grinding media made from yttrium stabilized zirconia. Drug compound and drug nanosuspension were characterized initially by their mechanical and rheological properties. The generation of wear from grinding media has been investigated simultaneously with the reduction of drug particle size by evaluating several grinding media supplier and diameter as well as process parameters stirrer tip speed and specific energy input. Grinding media quality and process parameters were identified with strong impact on the amount of generated wear and on drug particle size distribution. Wear from grinding media characterized by elemental zirconium and yttrium could be significantly minimized by operating with the favored grinding media quality and with optimal stirrer tip speed and specific energy input. Wear debris, respectively wear particles from grinding media, were identified with respect to morphology and particle size. Finally, the overall contamination by raw materials and by wear during processing characterized by elemental iron, silicium, yttrium and zirconium as well as the mean size of contamination particles are presented for selected drug nanosuspensions. PMID:22269938

  10. Microstructure Characterization of Mechanically Activated Talc in Jet Mill Using XRD Line Broadening Technique

    Science.gov (United States)

    Palaniandy, S.; Azizli, K. A. M.

    2010-03-01

    Fine grinding process of talc was carried out in jet mill by varying the operational parameter such as feed rate, classifier frequency and grinding pressure. The size reduction and mechanochemical effect of talc take place simultaneously as jet mill is an energy intensive grinding mill. The minimum particle size obtained was 4.28 ?m with span value of 1.30. The crystallinity values of ground product ranging from 71% to 91%. The crystallite size of the ground silica is ranging from 147.69 nm to 353.72 nm whilst the lattice strain was ranging from 0.08 to 0.20. After sonication process in ulrea sonic bath, the ground talc were in nano sheet where its thickness was around 20 nm.

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

    CERN Document Server

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

    2011-01-01

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

  12. Multi-stage FE simulation of hot ring rolling

    Science.gov (United States)

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

    2013-05-01

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

  13. High-speed milling of light metals

    Directory of Open Access Journals (Sweden)

    F. Cus

    2007-09-01

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

  14. 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)

  15. Quenching simulation of steel grinding balls

    OpenAIRE

    Zapata-Hernndez, Oscar; Reyes, Luis A.; Camurri, Carlos; Carrasco, Claudia; Garza-Montes-de-Oca, Nelson F.; Cols, Rafael

    2015-01-01

    The phase transformations of high carbon steel during quenching and equalizing were modelled using commercial computer packages based on the finite element method and the kinetic transformation of steel. The model was used to predict the temperature and microstructural changes taking place within balls of two different sizes that are used for grinding mineral ores. A good correlation between the temperatures measured by inserted thermocouples and those predicted by the model was obtained afte...

  16. Vibration syndrome and vibration in pedestal grinding.

    OpenAIRE

    Starck, J; Frkkil, M; Aatola, S; Pyykk, I; Korhonen, O

    1983-01-01

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

  17. A reliability analysis for the grinding process

    OpenAIRE

    Tolvanen, Pekka

    2011-01-01

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

  18. Freeform grinding and polishing with PROSurf

    Science.gov (United States)

    Wolfs, Franciscus; Fess, Edward; DeFisher, Scott; Torres, Josh; Ross, James

    2015-10-01

    Recently, the desire to use freeform optics has been increasing, including shapes such as torics and anamorphic aspheres. Freeform optics can be used to expand capabilities of optical systems. They can compensate for limitations in rotationally symmetric optics. These same traits that give freeform optics the ability to improve optical systems also makes them more challenging to manufacture. This holds true for grinding, polishing, and metrology. As freeform optics become more prevalent in the industry, tolerances will become more stringent, requiring deterministic manufacturing processes. To generate freeforms, it is crucial to have control over all aspects of the process. Controlling the surface definition is important for achieving a better surface finish during processing. Metrology will be required to adjust tool paths at various stages in manufacturing. During grinding, metrology will be used to adjust tool positions relative to the nominal tool path to compensate for repeatable machine and tooling error. For polishing, metrology will be used to deterministically adjust dwell relative to the amount of the error in different surface locations, allowing for convergence towards the desired surface at a uniform rate. OptiPro has developed PROSurf, a CAM software package for creating freeform tool paths and applying metrology-based corrections. The software can be used for both grinding and polishing freeform optics. The software has flexibility to allow for different methods of modelling the surface: mathematical equations, solid models, and point clouds. The software is designed to make it easier to manufacture and polish complex freeform optics.

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

    International Nuclear Information System (INIS)

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

  20. 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

  1. Recent developments in semiprocessed cold rolled magnetic lamination steel

    International Nuclear Information System (INIS)

    Over the past 10 years the magnetic property performance of semi-processed cold rolled magnetic lamination steels in North America have approached those of nonoriented, semi-processed silicon steel. This improvement was accomplished via higher alloy levels in conjunction with hot band annealing. New temper rolling strategies can produce weakly oriented steels tailored to specific applications, such as small transformers used in fluorescent lighting ballasts. Recently, production trials for 0.0138 in product cold rolled on tin mills has been undertaken. Efforts to further improve properties through a better understanding of texture control and via implementation of new production processes, such as thin slab or strip casting, continue

  2. Performance of Disk Mill Type Mechanical Grinder for Size Reducing Process of Robusta Roasted Beans

    Directory of Open Access Journals (Sweden)

    Sri Mulato

    2006-12-01

    Full Text Available One of improtant steps in secondary coffee processing that influence on final product quality such as consistency and uniformity is milling process. Usually, Indonesian smallholder used "lumpang" for milling coffee roasted beans to coffee powder product which caused the final product not uniformed and consistent, and low productivity. Milling process of coffee roasted beans can be done by disk mill type mechanical grinder which is used by smallholder for milling several cereals. Indonesian Coffee and Cocoa Research Institute have developed disk mill type grinding machine for milling coffee roasted beans. Objective of this research is to find performance of disk mill type grinding machine for size reducing process of Robusta roasted beans from several size dried beans and roasting level treatments. Robusta dried beans which are taken from dry processing method have 1314% moisture content (wet basis, 680685 kg/m3 density, and classified in 3 sizes level. The result showed that the disk mill type of grinding machine could be used for milling Robusta roasted beans. Machine hascapacity 3154 kg/h on 5,3105,610 rpm axle rotation and depend on roasting level. Other technical parameters were 9198% process efficientcy, 1931 ml/ kg fuel consumption, 0.31% slips, 5055% particles had diameter less than 230 mesh and 3844% particles had diameter bigger than 100 mesh, 3238% lightness was increased, 0.612.6% density was decreased, and solubility of coffee powder between 2830%. Cost milling process per kilogram of Robusta roasted beans which light roast on capacity 30 kg/hour was Rp362.9. Key words : Coffee roasted, Robusta, disk mill, mechanical grinder, size reduction.

  3. 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)

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Cavaguti, M.; Ferreira, J. V.

    2010-06-01

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

  6. 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)

  7. Energy requirement for fine grinding of torrefied wood

    OpenAIRE

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

    2010-01-01

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

  8. Grinding Surface Creation using Finite Element Method and Molecular Dynamics

    OpenAIRE

    Chen, X.; Opoz, Tahsin Tecelli; Oluwajobi, Akinjide O.

    2012-01-01

    This paper presents some research results of the application of finite element method and molecular dynamics in the simulation of grinding surface creation. The comparison of these two methods shows that both methods could illustrate the material removal phenomena and provide useful information of grinding mechanics, but they have different feasible application arranges depending on the level of size scales. The investigation demonstrated that rubbing hypothesis of grinding material removal m...

  9. Fundamentals of grinding : surface conditions of ground materials

    OpenAIRE

    Hegeman, Johannes Bernardus Jan-Willem,

    2000-01-01

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

  10. 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.

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

    Science.gov (United States)

    Pawlik, T.; Sopicka-Lizer, M.; W?odek, T.; Miku?kiewicz, M.

    2011-05-01

    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.

  12. 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

  13. CHARACTERIZATION OF THE FRICTION CONDITIONS IN THE FINISHING STANDS OF A HOT STRIP MILL

    Directory of Open Access Journals (Sweden)

    Antonio Augusto Gorni

    2012-06-01

    Full Text Available The decrease in hot strength or even rolling load as strain increases in some stands of the finishing hot strip mill with no metallurgical reasons is a relatively common event. Apparently this fact is associated with modification in the tribological conditions between rolling stock and work roll surfaces due to unexpected interactions with scale. The aim of this work is to determine the values of the friction coefficient in the several stands of the finishing hot strip mill at Usiminas-Cubato, as well to determine quantitative relationships between this coefficient and relevant process parameters, like strain degree and peripherical work roll speed.

  14. Kinetics of wet grinding of submicrone tungsten carbide powders

    International Nuclear Information System (INIS)

    The influence of temperature of ultradisperse tungsten carbidizing treatment on dispersion, fine structure and character of carbide frinding in the process of mixture preparation with 8%Co was studied. Considerable difference in grinding kinetics for submicron doped and standard tungsten carbide during wet grinding was ascertained. It is expressed in a less intensive growth of characteristics of dispersion and X-ray band width of submicron powder. It proved possible to reduce grinding time of mixtures on the basis of such powders. A change in grinding ability of finely dispersed tungsten carbide with an increase in the temperature of its production up to 1600-1700 deg C was detected

  15. Quenching simulation of steel grinding balls

    Energy Technology Data Exchange (ETDEWEB)

    Zapata-Hernandez, O.; Reyes, L. A.; Camurri, C.; Carrasco, C.; Garza-Monte-de-Oca, F.; Colas, R.

    2015-07-01

    The phase transformations of high carbon steel during quenching and equalizing were modelled using commercial computer packages based on the finite element method and the kinetic transformation of steel. The model was used to predict the temperature and microstructural changes taking place within balls of two different sizes that are used for grinding mineral ores. A good correlation between the temperatures measured by inserted thermocouples and those predicted by the model was obtained after modifying the thermal conductivity of the steel within the temperature domain at which mixed phases are present. The phase transformations predicted were confirmed by metallographic analyses. (Author)

  16. Rolling friction and bistability of rolling motion

    CERN Document Server

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

    2005-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-06-15

    The effects of grinding on certain crystalline substances (ZnO, ZnS, Sb), have been studied using X-ray diffraction and electron microscopy. The treatments were carried out using a vibrating mill which involves a higher energy than more conventional equipment such as ball-mills. Various methods have been proposed for determining the width of the intrinsic profile ({beta}). In the case of zinc oxide it has been shown possible to differentiate the respective contributions of the fragmentation effects and of lattice deformation effects to the overall effects of the grinding. For the two types of zinc sulfide (blend and Wurtzite) it has been shown that the blend-wurtzite) transition point is very much decreased, and that the rate of transformation of wurtzite into the stable form (blend) at room temperature is considerably increased by the grinding. In the case of antimony, the method of fragmentation shows the existence of an anisotropy which appears to be connected with easily cleavable planes. These observations show that in the case of grinding carried out with sufficient energy, the accumulation of this energy in the matter through the creation of lattice defects can accelerate the reaction rate or bring about physical transformations. (author) [French] Les effets du broyage sur certains corps cristallises (ZnO, ZnS, Sb) ont ete etudies a l'aide de la diffraction de rayons X et de la microscopie electronique. Les broyages ont ete effectues au moyen d'un vibro-broyeur qui met en jeu une energie superieure par rapport aux appareils plus conventionnels tels que les broyeurs a boulets. Diverses methodes concernant la determination de la largeur du profil intrinseque ({beta}) ont ete proposees. Dans le cas de l'oxyde de zinc on a montre la possibilite de differencier les contributions de l'effet de fragmentation et celui de perturbation du reseau, a l'effet total du broyage. Avec les deux varietes de sulfure de zinc (blende et Wurtzite) on a montre que le point de transformation de la blende en Wurtzite) etait fortement abaisse et que la transformation de la Wurtzite vers la forme stable (blende) a la temperature ambiante etait considerablement acceleree par le broyage. Dans le cas de l'antimoine le mode de fragmentation fait apparaitre une anisotropie qui doit etre reliee a l'existence des plans de clivage facile. Ces observations montrent que dans le cas d'un broyage effectue avec une energie suffisante, l'accumulation de cette energie dans la matiere par creation de defauts de reseau peut accelerer la vitesse de reaction ou provoquer des transformations physiques. (auteur)

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

    Science.gov (United States)

    Gomes, Marcos da Silva; Santos, Drio; Nunes, Lidiane Cristina; de Carvalho, Gabriel Gustinelli Arantes; Leme, Flvio de Oliveira; Krug, Francisco Jos

    2011-09-30

    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

  19. Model Predictive Control for an Industrial SAG Mill

    DEFF Research Database (Denmark)

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

    2012-01-01

    We discuss Model Predictive Control (MPC) based on ARX models and a simple lower order disturbance model. The advantage of this MPC formulation is that it has few tuning parameters and is based on an ARX prediction model that can readily be identied using standard technologies from system identication. When applied to MIMO systems we call this controller a MIMO-ARX based MPC. We use an industrial Semi-Autogenous Grinding (SAG) mill to illustrate the performance of this controller. SAG mills are ...

  20. Mechanical alloying of powder materials by ultrasonic milling.

    Science.gov (United States)

    Mordyuk, B N; Prokopenko, G I

    2004-04-01

    An ultrasonic grinding mill was designed. It permits to carry out simultaneously intensive ultrasonic, mechanical and cavitation treatments of powder materials that in turn leads to sharp acceleration of diffusion, mass-transfer processes and solid phase reactions due to crystallite size and structure changing. It was shown that meta-stable non-equilibrium solid solution (Cu+Ni+Fe, Fe+C), and crystalline structure transformed (Fe(4)N: fcc-hcp transformation) powders could be obtained for the much shorter time in compare with traditional mechanical alloying in planetary ball mill. PMID:15047259

  1. Ship Roll Damping Control

    DEFF Research Database (Denmark)

    Perez, Tristan; Blanke, Mogens

    2012-01-01

    The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of difficulties associated with control system designs, which have proven to be far from trivial due to fundamental performance limitations and large variations of the spectral characteristics of wave-induced roll motion. This tutorial paper presents an account of the development of various ship roll motion control systems tog...

  2. Validation of the Hot Strip Mill Model

    Energy Technology Data Exchange (ETDEWEB)

    Richard Shulkosky; David Rosberg; Jerrud Chapman

    2005-03-30

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

  3. Rolling Shutter Motion Deblurring

    KAUST Repository

    Su, Shuochen

    2015-06-07

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

  4. Effect of grinding intensity and pelleting of the diet on indoor particulate matter concentrations and growth performance of weanling pigs.

    Science.gov (United States)

    Ulens, T; Demeyer, P; Ampe, B; Van Langenhove, H; Millet, S

    2015-02-01

    This study evaluated the effect of feed form and grinding intensity of the pig diet and the interaction between both on the particulate matter (PM) concentrations inside a pig nursery and the growth performances of weanling pigs. Four diets were compared: finely ground meal, coarsely ground meal, finely ground pellets, and coarsely ground pellets. Four weaning rounds with 144 pigs per weaning round, divided over 4 identical compartments, were monitored. Within each weaning round, each compartment was randomly assigned to 1 of 4 treatments. A hammer mill with a screen of 1.5 or 6 mm was used to grind the ingredients of the finely ground and coarsely ground feeds, respectively. Indoor concentrations of the following PM fractions were measured: PM that passes through a size-selective inlet with a 50 % efficiency cutoff at 10 (PM10) , 2.5 (PM2.5), or 1 (PM1) ?m aerodynamic diameter, respectively (USEPA, 2004). Feeding pelleted diets instead of meal diets gave rise to higher PM10 (P feed form and grinding intensity was found for any of the PM fractions. Interactions (P feed form and grinding intensity on ADFI and ADG were found. Grinding intensity had an effect only on the meal diets with higher ADFI for the coarsely ground meal. Pigs fed the finely ground meal had a lower (P Feed efficiency was influenced only by the feed form (P feed gave rise to a higher G:F. In conclusion, a contradiction between environmental concerns and performance results was found. Feeding pelleted diets to the piglets improved growth performance but also increased indoor PM concentrations. PMID:25548204

  5. 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)

  6. Cocrystal Formation through Mechanochemistry: from Neat and Liquid-Assisted Grinding to Polymer-Assisted Grinding.

    Science.gov (United States)

    Hasa, Dritan; Rauber, Gabriela Schneider; Voinovich, Dario; Jones, William

    2015-06-15

    Mechanochemistry is an effective method for the preparation of multicomponent crystal systems. In the present work, we propose an alternative to the established liquid-assisted grinding (LAG) approach. Polymer-assisted grinding (POLAG) is demonstrated to provide a new class of catalysts for improving reaction rate and increasing product diversity during mechanochemical cocrystallization reactions. We demonstrate that POLAG provides advantages comparable to the conventional liquid-assisted process, whilst eliminating the risk of unwanted solvate formation as well as enabling control of resulting particle size. It represents a new approach for the development of functional materials through mechanochemistry, and possibly opens new routes toward the understanding of the mechanisms and pathways of mechanochemical cocrystal formation. PMID:25939405

  7. Grinding Characteristics of Reaction Bonded Silicon Carbide

    Directory of Open Access Journals (Sweden)

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

    2012-07-01

    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.

  8. Chirality Change by Grinding Crystals in Solution

    International Nuclear Information System (INIS)

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

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

    Scientific Electronic Library Online (English)

    Eduardo Carlos, Bianchi; Eraldo Jannone da, Silva; Vinicio Lucas, Vargas; Thiago Cardoso, Magagnin; Rodrigo Daun, Monici; Osmar, Vicari Filho; Paulo Roberto de, Aguiar.

    2002-10-01

    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 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.

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

    Directory of Open Access Journals (Sweden)

    Bianchi Eduardo Carlos

    2002-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    ROMAN, N.

    2010-02-01

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

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

    Directory of Open Access Journals (Sweden)

    M. Drobne

    2014-10-01

    Full Text Available Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for rolls 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 electromechanical testing machine was used.

  13. Effect of Mechanical Grinding and Ionic Liquid Pre-Treatment on Oil Palm Frond

    International Nuclear Information System (INIS)

    The present study was set to investigate the chemical structural group of different particle size of Oil palm frond (OPF) after mechanical and Ionic liquid (IL) pretreatment by FTIR analysis. The particle sizes range of biomass used were 0-75, 75-125, 125-180, 180-250 and 250-355 μm which were prepared through mechanical grinding process by using an analytical mill. IL used in this experiment was 1-ethyl-3-methylimidazolium chloride [EMIM][Ac] with two different concentration of 1M and 3M. Pretreatment by IL was done on BioshakeIQ for 3 hours at 800 rpm and 85 degree Celsius. The pretreated OPF was then analyzed using FTIR spectroscopy in order to evaluate the performance of mechanical grinding and IL pretreatment based on the change observed in chemical structure through functional group existed. It was found that after size reduction through grinding process, the spectra between all particle sizes obtained did not differ much except for particle size range of 75-125 μm. The particle size range showed on much characteristics of cellulose due to the broad peak within the 3600-3100 cm-1 which stand for O-H bonding. However, when the FTIR spectra were compared between before and after IL pretreatments, there were some different in peaks trend which explained there were some chemical structure changes within the OPF samples. There were some appearances and disappearances of certain peak were observed after the IL pretreatment especially the peak at band near 1700 cm-1 and 1550 cm-1. (author)

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

    Directory of Open Access Journals (Sweden)

    Tong Junfeng

    2013-04-01

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

  15. 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 (3590 nm) and equivalent size of the specific surface area (41191 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.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Lestage, R.; Pomerleau, A. [Univ. Laval, Groupe de Recherche sur les Applications de l' Informatique a l' industrie Minerale, Dept. de genie electrique et de genie informatique, Sainte-Foy, PQ (Canada)

    1999-07-01

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

  18. Cryogenic grinding technology for traditional Chinese herbal medicine

    Science.gov (United States)

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

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

  19. Methodology for automatic selection of passes in surface grinding

    Scientific Electronic Library Online (English)

    Fbio R. L., Dotto; Paulo Roberto de, Aguiar; Rogrio, Thomazella; Eduardo Carlos, Bianchi.

    2007-03-01

    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 fo [...] r automatic selection of the grinding passes, therefore, requiring the users 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.

  20. Numerical analysis of small recessed silicon carbide grinding wheels

    Directory of Open Access Journals (Sweden)

    M.J. Jackson

    2010-11-01

    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.

  1. Eco-efficiency of grinding processes and systems

    CERN Document Server

    Winter, Marius

    2016-01-01

    This research monograph aims at presenting an integrated assessment approach to describe, model, evaluate and improve the eco-efficiency of existing and new grinding processes and systems. Various combinations of grinding process parameters and system configurations can be evaluated based on the eco-efficiency. The book presents the novel concept of empirical and physical modeling of technological, economic and environmental impact indicators. This includes the integrated evaluation of different grinding process and system scenarios. The book is a valuable read for research experts and practitioners in the field of eco-efficiency of manufacturing processes but the book may also be beneficial for graduate students.

  2. MECHANICAL GRINDING OF SOLID POWDER MATERIALS

    Directory of Open Access Journals (Sweden)

    Dmitrenko D. V.

    2015-10-01

    Full Text Available The article is dedicated to the determination of conditions for solid bodies fragmentation, providing minimal size of particles by means of their mechanical dispersion through the example of powders of titanium carbide (TiC, cubic boron nitride borazon (CBN and boron carbide (B4C. The theoretical and practical aspects of the process of mechanical fragmentation of particles of solid powder materials in ball mill for their further utilization in furnace charge for high-speed gas-flame sputtering of wear-resistant composite materials are examined in the article. Methods of preliminary calculation of minimum allowable size of solid particles of powder materials during mechanical fragmentation, based upon Griffiths mechanical theory of rapture using experimental data for hardness of material and its yield are proposed and theoretically substantiated. There we have the results of experiments on mechanical fragmentation of titanium carbide in attritor, boron carbide and cubic boron nitride in centrifugal planetary mill, confirming correctness of theoretical propositions and calculations are set out. Recommendations on mechanical fragmentation of solid powder materials in ball mills are formulated as well

  3. Annular Fuel Pellet Fabrication without Surface Grinding

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Nur Rafidah Yahaya

    2012-01-01

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

  5. A critical study of high efficiency deep grinding

    CERN Document Server

    Johnstone, I

    2002-01-01

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

  6. Gemstone Grinding Process Improvement by using Impedance Force Control

    Directory of Open Access Journals (Sweden)

    Hamprommarat Chumpol

    2015-01-01

    Full Text Available Chula Automatic Faceting Machine has been developed by The Advance Manufacturing Research Lab, Chulalongkorn University to support Thailand Gems-Industry. The machine has high precision motion control by using position and force control. A contact stiffness model is used to estimate grinding force. Although polished gems from the Faceting Machine have uniform size and acceptable shape, the force of the grinding and polishing process cannot be maintain constant and has some fluctuation due to indirect force control. Therefor this research work propose a new controller for this process based on an impedance direct force control to improve the gemstone grinding performance during polishing process. The grinding force can be measured through motor current. The results show that the polished gems by using impedance direct force control can maintain uniform size as well as good shape and high quality surface.

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

    International Nuclear Information System (INIS)

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

  8. In-Process Chatter Detection in Surface Grinding

    Directory of Open Access Journals (Sweden)

    Tangjitsitcharoen Somkiat

    2015-01-01

    Full Text Available The chatter causes the poor surface finish during the surface grinding. It is therefore necessary to monitor the chatter during the process. Hence, this research has proposed the in-process chatter detection in the surface grinding process by utilizing the dynamic cutting forces. The ratios of the average variances of three dynamic cutting forces have been adopted and applied to identify the chatter during the surface grinding process to eliminate the effects of the cutting conditions. The effects of the cutting conditions on the chatter are also studied and analyzed. The algorithm has been proposed to detect the chatter regardless of the cutting conditions. The verification of the proposed system has been proved through another experiment by using the new cutting conditions. The experimental results have run satisfaction. It is understood that the chatter can be avoided during the in-process surface grinding even though the cutting conditions are changed.

  9. Dry grinding effect on pyrophyllite-quartz natural mixture and its influence on the structural alternation of pyrophyllite.

    Science.gov (United States)

    Zhang, Jian; Yan, Jun; Sheng, Jiawei

    2015-04-01

    Infrared spectroscopy (IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM) with energy dispersive X-ray analysis (EDS) were used to investigate the evolution of mechanical destruction of the pyrophyllite structure and final ground products upon grinding with a laboratory planetary ball mill. The raw ore used in this present work was mainly composed of pyrophyllite and quartz. This pyrophyllite was more resistant toward mechanical destruction, and the crystalline order of pyrophyllite was not completely destroyed until grinding for 240 min with a 20:1 of weight ratio of the balls to powder. The existing crystalline phase in the final ground product was found to be quartz, which served as the associated phase in the original pyrophyllite mineral. The rate of destruction of pyrophyllite structure depended on the types of chemical bonds. Additionally, increasing the intensity of grinding resulted in acceleration of the mechanically induced amorphization of the pyrophyllite structure, whereas the associated quartz grains contributed to the deceleration of the amorphization of pyrophyllite. PMID:25590567

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

  12. Quenching simulation of steel grinding balls

    Directory of Open Access Journals (Sweden)

    Zapata-Hernndez, Oscar

    2015-09-01

    Full Text Available The phase transformations of high carbon steel during quenching and equalizing were modelled using commercial computer packages based on the finite element method and the kinetic transformation of steel. The model was used to predict the temperature and microstructural changes taking place within balls of two different sizes that are used for grinding mineral ores. A good correlation between the temperatures measured by inserted thermocouples and those predicted by the model was obtained after modifying the thermal conductivity of the steel within the temperature domain at which mixed phases are present. The phase transformations predicted were confirmed by metallographic analyses.Las transformaciones de fase en aceros de alto carbono durante su temple y un posterior periodo de estabilizacin fueron modelizadas por medio del uso de paquetes computacionales basados en el mtodo del elemento finito y de la transformacin cintica de los aceros. El modelo se us para predecir los cambios de temperatura y microestructura que se presentan en bolas de dos diferentes tamaos empleadas en estaciones de molienda de minerales. Se encontr una buena correlacin entre las temperaturas medidas mediante la insercin de termopares y aquellas predichas por el modelo una vez que se modific la conductividad trmica del acero en el intervalo mixto de fases. La prediccin de las transformaciones de fase se confirm a travs del anlisis metalogrfico.

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

    OpenAIRE

    Mohammed, Arif

    2012-01-01

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

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

    OpenAIRE

    Daniel Véras Ribeiro; Márcio Raymundo Morelli

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-05-01

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

  16. Design and fabrication of nano-scale single crystal diamond cutting tool by focused ion beam (FIB) milling

    Science.gov (United States)

    Baek, Seung-Yub

    2015-07-01

    Micro/nanoscale diamond cutting tools used in ultra-precision machining can be fabricated by precision grinding, but it is hard to fabricate a tool with a nanometric cutting edge and complex configurations. High-precision geometry accuracy and special shapes for microcutting tools with sharp edges can be achieved by FIB milling. Because the FIB milling method induces much smaller machining stress compared with conventional precision grinding methods. In this study, the FIB milling characteristics of single-crystal diamond were investigated, along with methods for decreasing the FIB-induced damage on diamond tools. Lift-off process method and Pt(Platinum) coating process method with FIB milling were investigated to reduce the damage layer on diamond substrate and quadrilateral-shaped single-crystal diamond cutting tool with cutting edge width under 500 nm were obtained.

  17. Grinding process monitoring based on electromechanical impedance measurements

    Science.gov (United States)

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

    2015-04-01

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

  18. Grooved roll for a high speed twin roll caster

    Directory of Open Access Journals (Sweden)

    T. Haga

    2008-04-01

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

  19. Biomechanics of leukocyte rolling

    OpenAIRE

    Sundd, Prithu; POSPIESZALSKA, MARIA K.; Cheung, Luthur Siu-Lun; Konstantopoulos, Konstantinos; Ley, Klaus

    2011-01-01

    Leukocyte rolling on endothelial cells and other P-selectin substrates is mediated by P-selectin binding to P-selectin glycoprotein ligand-1 expressed on the tips of leukocyte microvilli. Leukocyte rolling is a result of rapid, yet balanced formation and dissociation of selectin-ligand bonds in the presence of hydrodynamic shear forces. The hydrodynamic forces acting on the bonds may either increase (catch bonds) or decrease (slip-bonds) their lifetimes. The force-dependent catch-slip bond ...

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

    OpenAIRE

    R. ?wi?cik

    2009-01-01

    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...

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Fernndez Luco, L.

    2003-12-01

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

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

  3. Spray Rolling Aluminum Strip

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-05-10

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

  4. The Evolution of the Surface Morphologies and Microstructures of an Unleveled Hot-Rolled Steel Strip During Cold Rolling After Hydrogen Reduction

    Science.gov (United States)

    Jing, Yu-An; Shang, Qiuyue; Zang, Xiaoming; Zhang, Lei; Peng, Xingdong; Jia, Pinfeng

    2015-10-01

    The removal of oxide scale from a hot-rolled strip surface can completely eliminate environmental pollution if performed by hydrogen-reduction descaling instead of traditional pickling descaling. However, a large number of cracks appear on the surface of a leveled hot-rolled steel strip after hydrogen reduction. This effect is likely to impede the application of reduction descaling to cold-rolled products. Nevertheless, there are almost no cracks on the surface of an unleveled hot-rolled steel strip if the hot-rolled steel strip is not subjected to repeated bending by the leveler machine. The surface quality of a reduced steel strip will be better than that of a pickled steel strip. To investigate the evolution of the surface morphologies, microstructures, and properties of an unleveled strip steel during cold rolling, unleveled strip steel samples were rolled using a four-high mill after hydrogen reduction and after pickling. The surface morphologies and cross-sectional microstructures of the samples were observed by SEM, and the surface-roughness values were measured using a TR200 profilometer before and after cold-rolling deformation. The evolution of the surface morphologies and cross-sectional microstructures of the sample after cold rolling were analyzed. The results show that the oxide scale formed on the surface turns into a metallic iron layer, and a decarburization layer appears between the metallic iron layer and the steel matrix after hydrogen reduction. Few cracks, besides pores, and bubbles, appeared on the surface of the sample after hydrogen reduction. The pores and bubbles were roll-flattened after five passes of cold rolling. The work hardening degree and mechanical properties of the reduced sample are similar to those of the pickled sample after cold rolling. Compared with the rolled sample after pickling, the surface qualities of the reduced samples are better than those of the pickled samples and better than those of the reduced samples that were subjected to leveling prior to reduction.

  5. Improved Billet Shape Modeling in Optimization of the Hot Rod and Wire Rolling Process

    OpenAIRE

    Betshammar, Jan

    2006-01-01

    The hot rod and wire rolling process is widely used to produce rolled iron alloys in different shapes and dimensions. This industry has been under a constant development during the last decades. Today, complex geometries are produced at a high speed since it is possible to use several stands in each mill at the same time. A reason for the development is rising demands from customers. The most important demands are to save energy, to get better material properties and higher dimension accuracy...

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, K.M. [Industrial Technology Department, Idaho National Laboratory, Idaho Falls, ID 83415-2050 (United States)], E-mail: kevin.mchugh@inl.gov; Lin, Y.; Zhou, Y.; Johnson, S.B.; Delplanque, J.-P.; Lavernia, E.J. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States)

    2008-03-25

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

  8. Ultraprecision grinding of optical materials for high-power lasers

    Science.gov (United States)

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

    1998-04-01

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

  9. Ductile streaks in precision grinding of hard and brittle materials

    Indian Academy of Sciences (India)

    V C Venkatesh; S Izman; S Sharif; T T Mon; M Konneh

    2003-10-01

    Ductile streaks produced during diamond grinding of hard and brittle materials have aided the subsequent process of polishing. Two novel techniques were used to study the formation of ductile mode streaks during diamond grinding (primary process) of germanium, silicon, and glass. In the first technique, aspheric surfaces were generated on Ge and Si at conventional speeds (5000 rpm). In the second technique, diamond grinding of plano surfaces on glass and Si surfaces using high speed (100,000 rpm) was carried out. Form accuracy, surface finish and ductile mode grinding streaks are discussed in this paper. It was found that resinoid diamond wheels gave more ductile streaks than metal-bonded wheels but better form accuracy was obtained with the latter. Ductile streaks were obtained more easily with pyrex rather than with BK 7 glass thus necessitating very little time for polishing. Ductile streaks appeared in abundance on germanium rather than silicon. Both the novel grinding techniques were used on CNC machining centres.

  10. Critical parameters for grinding large sapphire window panels

    Science.gov (United States)

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

    2007-04-01

    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.

  11. Development of morphology in laser dressed grinding wheels

    Directory of Open Access Journals (Sweden)

    M.J. Jackson

    2007-05-01

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

  12. Sliding and Rolling: The Physics of a Rolling Ball.

    Science.gov (United States)

    Hierrezuelo, J.; Carnero, C.

    1995-01-01

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

  13. Ship Roll Motion Control

    DEFF Research Database (Denmark)

    Perez, Tristan; Blanke, Mogens

    2010-01-01

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

  14. Texture comparison between cold rolled and cryogenically rolled pure copper

    Science.gov (United States)

    Lapeire, L.; Sidor, J.; Martinez Lombardia, E.; Verbeken, K.; De Graeve, I.; Terryn, H.; Kestens, L. A. I.

    2015-04-01

    Nowadays, there is a considerable scientific interest in bulk ultrafine grained materials, due to their potential for superior mechanical properties. One of the possible formation methods of nano-grained materials is cryogenic rolling. The influence of rolling at cryogenic temperatures has been investigated. Significant differences in the textures and the microstructures can be observed between the cryogenically rolled copper and conventionally cold rolled copper, reduced to the same thickness.

  15. EVOLUTION OF THE AUSTENITE GRAIN SIZE DURING HOT STRIP ROLLING OF NIOBIUM MICROALLOYED STEELS

    OpenAIRE

    Antonio Augusto Gorni; Marcos Roberto Soares da Silva

    2015-01-01

    The occurrence of dynamic recrystallization in the intermediate stands of the Finishing Mill of a Hot Strip Mill promotes substantial softening of the rolling stock, a situation that can cause operational problems and even scrapping of the strip. The aim of this work was to identify the specific process conditions that can lead to this situation, which was carried out through the application of a microstructural evolution model. It was verified, for the specific conditions of the ...

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

    Directory of Open Access Journals (Sweden)

    Wjcik R.

    2014-10-01

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

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

    Scientific Electronic Library Online (English)

    Walter Lindolfo, Weingaertner; Adriano, Boaron.

    2012-03-01

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

  18. In-process grinding monitoring through acoustic emission

    Scientific Electronic Library Online (English)

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

    2006-03-01

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

  19. Characterization of grinding wheels: An annotated Bibliography. Final report

    Energy Technology Data Exchange (ETDEWEB)

    McClung, R.W.

    1995-12-01

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

  20. 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.

  1. Research on Grinding and Polishing Force Control of Compliant Flange

    Directory of Open Access Journals (Sweden)

    Li Chuang

    2015-01-01

    Full Text Available The automation of the grinding and polishing process is important to improve the production efficiency of the part surfaces. In this paper, a new compliant flange mounted on the end of the industrial robots for the robotic grinding and polishing force control is developed. With regard to the non-linear and time-varying problem of the contact force, the mathematical model of the new force control system was presented and the fuzzy PID control strategy was used to drive the proposed system. Especially, the air spring and electric proportional valve is studied to establish the model. The simulation results show that the selected control strategy has quick response and good robustness, which satisfies the real-time requirements of the grinding and polishing force control in processing.

  2. 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.)

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

    Directory of Open Access Journals (Sweden)

    A. Stefanik

    2008-03-01

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

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

    Scientific Electronic Library Online (English)

    Daniel Vras, Ribeiro; Mrcio Raymundo, Morelli.

    2009-03-01

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

  5. 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.)

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

    OpenAIRE

    A. Pribulov; Baricov, D.; P. Futa; P. Genge?

    2010-01-01

    Foundry dust can be divided into three groups: metallic dust with Fe content over 70%, mixed dust with Fe or SiO2 content between 10 70% and sand wastes with minimum content of SiO2 about 70%. Dust from castings grinding with high Fe content (87.9%) is still landfillin Slovakia. The aim of experiments with dust from grinding has been to find the cheapest way of dust agglomeration with minimumamount of binder because of melting in the electric induction furnace. The dust was pelletized and br...

  7. Study of thresholds to burning in surface grinding process

    Scientific Electronic Library Online (English)

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

    2005-06-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-04-15

    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.)

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

    Directory of Open Access Journals (Sweden)

    Daniel Véras Ribeiro

    2009-03-01

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

  10. Person og Rolle

    DEFF Research Database (Denmark)

    Szatkowski, Janek

    2011-01-01

    Distinktionen mellem person og rolle forsls som grundlag for et prcist og anlytisk anvendeligt begreb om performativitet. Begrebet tager sigte p at beskrive enkeltindividers og gruppers kommunikation med henblik p hvordan kommunikation etableres. Performativitet gr det muligt at iagttage den strukturelle kobling mellem psykiske stystemers bevidsthed og sociale systemers kommunikation, og derved bne for en diskussion af hvordan vrdier fungerer i en sdan kommunikation.

  11. Lokalpolitikeres rolle og rderum

    DEFF Research Database (Denmark)

    Holm Pedersen, Lene; Houlberg, Kurt

    2013-01-01

    I en ny og omfattende undersgelse fra KORA og CBS er alle landets lokalpolitikere blevet spurgt om, hvordan de oplever deres rolle og rderum. Undersgelsen belyser blandt andet, hvordan arbejdsvilkr og indflydelsesmuligheder er i dag, og hvordan vilkr og muligheder er blevet ndret de senere r.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-03-01

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

  13. Design and experimental study of a micro-groove grinding wheel with spray cooling effect

    Directory of Open Access Journals (Sweden)

    Shi Chaofeng

    2014-04-01

    Full Text Available The effectiveness of grinding fluid supply has a crucial impact on grinding quality and efficiency in high speed grinding. In order to improve the cooling and lubrication, through in-depth research of self-inhaling internal cooling method and intermittent grinding mechanism, a new spray cooling method used in high speed grinding is proposed. By referring to the structure of bowl-shaped dispersion disk, the grinding wheel matrix with atomization ability is designed; through studying heat transfer of droplet collision and the influence of micro-groove on the boiling heat transfer, grinding segment with micro-groove is designed to enhance the heat flux of coolant and achieve maximum heat transfer between droplets and grinding contact zone. High-speed grinding experiments on GH4169 with the developed grinding wheel are carried out. The results show that with the micro-groove grinding wheel just 5.4% of pump outlet flow rate and 0.5% of spindle energy is needed to reduce the grinding temperature to 200C, which means the developed grinding wheel makes cooling high efficient and low energy consuming.

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

    DEFF Research Database (Denmark)

    Laugier, Maxime; Boman, Romain

    2014-01-01

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

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

    Scientific Electronic Library Online (English)

    Pricles Guedes, Alves; Jos Adilson de, Castro; Luciano Pessanha, Moreira; Elder Moreira, Hemerly.

    2012-12-01

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

  16. Effect of pass schedule and groove design on the metal deformation of 38MnVS6 in the initial passes of hot rolling

    Indian Academy of Sciences (India)

    R S Nalawade; V R Marje; G Balachandran; V Balasubramanian

    2016-01-01

    The deformation behaviour of a hot rolled micro-alloyed steel bar of grade 38MnVS6 was examined using an FEM model during the initial passes in a blooming mill, as a function of three different pass schedules,roll groove depth, collar taper angle and corner radius. The simulations predicted the effective strain penetration,load, torque, fish tail billet end shapes, and metal flow behaviour at a chosen temperature, mill rpm and draft. The model predictions were validated for typical groove geometry and a typical pass schedule. Lower collar taper angle, lower corner radius and higher depth of groove in hot rolling enabled achievement of higher strain penetration, higher mill load and lower fish tail formation. The present study establishes the capability of the model to improve the internal quality of the rolled billet as measured by effective strain which was corroborated to the rolled bar macrostructure and microstructure. The model enables yield improvement by the choice of draft to minimise fish tail losses. The surface quality is improved by the ability to avoid fin formation that occurs at certain conditions of rolling. Thus, the groove geometry, roll pass schedule and rolling mill parameters and temperature can be optimised for best product quality and yield.

  17. Microstructure Evolution During Spray Rolling and Heat Treatment of 2124 Al

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-09-01

    Spray rolling is a strip casting technology that combines elements of spray forming and twin-roll casting. It consists of atomizing molten metal with a high velocity inert gas, quenching the resultant droplets in flight, and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets and conduction heat transfer at the rolls rapidly move an alloys latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly-solidified product. While similar in many ways to twin-roll casting, spray rolling is able to process a broader range of alloys and operates at a higher production rate. A laboratory-scale strip caster has been constructed at INL and used to evaluate the interplay of processing parameters and strip quality while producing strips up to 200 mm wide and 1.6 6.4 mm thick. Plans are underway to scale to 600 mm width and demonstrate steady-state operation. As-spray-rolled strip is characterized by a flat, uniformly thick profile with minimal porosity or segregation. This paper examines how processing parameters influence the microstructure transformations that take place during spray rolling and post-deposition heat treatment of 2124 Al.

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

    OpenAIRE

    Martin Novk; Nataa Nprstkov; Jerzy Jzwik

    2015-01-01

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

  19. Evaluation of superalloy heavy-duty grinding based on multivariate tests

    OpenAIRE

    Liu, Qiang; Chen, Xun; Gindy, Nabil

    2007-01-01

    The quality and economy of grinding depend on proper selection of grinding conditions for the materials to be ground. In order to evaluate the effect of heavy-duty grinding, a new performance index, which includes specific material removal rate, size accuracy, and grinding forces, was proposed. Robust design of experiment, including orthogonal arrays, the signal-to-noise ratio (SNR) method, and analysis of variance (ANOVA) for multivariate data, was employed to estimate the effect of uniform ...

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

    Directory of Open Access Journals (Sweden)

    Michelle K. McGinn

    2010-05-01

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

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

    OpenAIRE

    Annabelle L. Grundy; Michelle K. McGinn

    2010-01-01

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

  2. GRINDING OF SHAPED TOOLS ON CNC TOOL GRINDER

    Directory of Open Access Journals (Sweden)

    Jn Kr?

    2013-03-01

    Full Text Available Worm gears are special gears consisting of a worm wheel and a worm. Worm gears can be produced in different ways, depending on the size of the transmission, the number of courses, the pitch angle of worm profile, the number of units produced, the purpose of application, etc. As cylindrical worm gears we consider the cylindrical worms with globoid gears, globoid worm with globoid worm gear and globoid worm with cylindrical worm gearing. This paper deals with the evolvent worm whose curve of the tooth side in the front plane is evolvent. The production of worm with an optimal profile for optimal meshing conditions is an increasingly frequent focus of worm gear manufacturers. The problem of designing the tool cutting edge can be divided into several steps. This article deals with the problems of optimum design of a tool shape for the production of worms; and the problems of calculating the coordinates of the transition cutting edge shape, and thus the path of grinding wheel for sharpening the tool cutting edge shape are solved. By grinding tool of grinding machine we can complete the worm shape and also sharpen the cutting edges of tools for production of worm surface. The problems of calculation of the coordinates are solved with regard to the functioning of the KON 250 CNC grinding machine logic.

  3. Computer numerical control grinding of spiral bevel gears

    Science.gov (United States)

    Scott, H. Wayne

    1991-01-01

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

  4. 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

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

    Scientific Electronic Library Online (English)

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

    2006-06-01

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

  6. Facial lesions in piglets with intact or grinded teeth

    Directory of Open Access Journals (Sweden)

    Hansson Monica

    2012-04-01

    Full Text Available Abstract Background Piglets are born with eight sharp teeth that during nursing can cause facial lesions on littermates and teat lesions on the sow. Teeth grinding in piglets is therefore often practiced to reduce these lesions. The aim of this study was to assess the consequences of grinding piglet teeth in regard to the occurrence of lesions. In this study the piglets' teeth were grinded in 28 litters, and in 36 litters the piglets' teeth were kept intact. Twice, one time during the first week and one time during the second week after birth facial lesions of the piglets were scored and the teats of the sows were examined for lesions. The facial lesion score accounted for the amount and severity of lesions. The individual observations on piglets in the litter were synthesized in a litter facial lesion score. Findings 69.8% and 43.5% of the piglets had facial lesions in week 1 and week 2 respectively. The effect of treatment was not significant on litter facial lesion score. The litter facial lesion score was higher in week 1 than in week 2 (p p = 0.003 than in small litters. Mortality between week 1 and week 2 was higher in litters with intact teeth (p = 0.02. Sow teat lesions only occurred if litters had intact teeth. Conclusions According to our results teeth grinding is only justifiable in large litters.

  7. 30 CFR 56.14115 - Stationary grinding machines.

    Science.gov (United States)

    2010-07-01

    ... 56.14115 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Machinery and Equipment Safety Devices and Maintenance Requirements 56.14115 Stationary grinding machines....

  8. Contact and Non-contact Measurements of Grinding Pins

    Directory of Open Access Journals (Sweden)

    Magdziak Marek

    2015-01-01

    Full Text Available The paper presents the results of contact and non-contact measurements of external profiles of selected grinding pins. The measurements were conducted in order to choose the appropriate measuring technique in the case of the considered measurement task. In the case of contact measurements the coordinate measuring machine ACCURA II was applied. The used coordinate measuring machine was equipped with the contact scanning probe VAST XT and the Calypso inspection software. Contact coordinate measurements were performed by using of different measurement strategies. The applied strategies included different scanning velocities and distances between measured points. Non-contact measurements were conducted by means of the tool presetter produced by the Mahr company. On the basis of gained results the guidelines concerning measurements of grinding pins were formulated. The measurements of analyzed grinding pins performed by means of the non-contact measuring system are characterized by higher reproducibility than the contact measurements. The low reproducibility of contact measurements may be connected with the inaccuracy of the selected coordinate measuring machine and the measuring probe, the measurement parameters and environmental conditions in the laboratory where the coordinate measuring machine is located. Moreover, the paper presents the possible application of results of conducted investigations. The results of non-contact measurements can be used in the simulation studies of grinding processes. The simulations may reduce the costs of machining processes.

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

    Science.gov (United States)

    Farzanegan, A.; Ghalaei, A. Ebtedaei

    2015-03-01

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

  10. Walk and roll robot

    Science.gov (United States)

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

    2011-01-01

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

  11. Tenascin Supports Lymphocyte Rolling

    OpenAIRE

    Clark, Rachael A; Erickson, Harold P.; Springer, Timothy A

    1997-01-01

    Tenascin is a large extracellular matrix molecule expressed at specific sites in the adult, including immune system tissues such as the bone marrow, thymus, spleen, and T cell areas of lymph nodes. Tenascin has been reported to have both adhesive and anti-adhesive effects in static assays. We report here that tenascin supports the tethering and rolling of lymphocytes and lymphoblastic cell lines under flow conditions. Binding was calcium dependent and was not inhibited by treatment of ly...

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

    OpenAIRE

    Lszl Forr; Richard Gaal; Claudio Grimaldi; Marijana Mioni?; Primo Rebernik Ribi?; Rita Smajda; Arnaud Magrez

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Hameedur Rehman Khan

    2014-07-01

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

  14. Microstructural Characterization of Calcite-Based Powder Materials Prepared by Planetary Ball Milling

    OpenAIRE

    Wen-Tien Tsai

    2013-01-01

    In this work, a planetary ball milling was used to modify the surface properties of calcite-based material from waste oyster shell under the rotational speed of 200600 rpm, grinding time of 5180 min and sample mass of 110 g. The milling significantly changed the microstructural properties of the calcite-based minerals (i.e., surface area, pore volume, true density, and porosity). The surface characterization of the resulting powder should be macroporous and/or nonporous based on the nitrog...

  15. 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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan Province 410082 (China); College of Mechanical and Vehicle Engineering, Hunan University, Changsha, Hunan Province 410082 (China); Fang, Qihong, E-mail: fangqh1327@hnu.edu.cn [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan Province 410082 (China); College of Mechanical and Vehicle Engineering, Hunan University, Changsha, Hunan Province 410082 (China); Zhang, Liangchi [School of Mechanical and Manufacturing Engineering, The University of New South Wales, NSW 2052 (Australia); Liu, Youwen [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan Province 410082 (China); College of Mechanical and Vehicle Engineering, Hunan University, Changsha, Hunan Province 410082 (China)

    2015-01-01

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

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

    Scientific Electronic Library Online (English)

    B., Clermont; B., de Haas.

    2010-03-01

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

  19. Chatter Prediction in End Milling by FNN Model with Pruning

    Science.gov (United States)

    Hino, Junichi; Okubo, Seiichi; Yoshimura, Toshio

    This paper is concerned with a study of chatter prediction in high-speed end milling operations. Chatter vibration occurring in mechanical machining gives rise to poor surface finish and dimensional inaccuracy in machined parts, reduction of tool life, and even damages machine tools. Various studies of its prediction and avoidance have been carried out over the last several decades. The purpose of this study is to develop an expert system for predicting chatter vibrations in high-speed end milling using wavelet transform and fuzzy neural network models with pruning. The FNN model employed here uses a pruning process which reduces a neural network to its most effective size. The amount of learning for convergence of a pruned network is reduced in comparison with an initial network. The proposed method is applied to a jig grinding machine, and the results demonstrate the effectiveness of the chatter prediction procedure.

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

    Science.gov (United States)

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

    2013-10-01

    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 5.1W and 4.9W respectively at wheat flow rate of 1.6Kg/s and dampener wheel rotational velocity of 4.4rad/s. PMID:24426010

  1. Microstructural Characterization of Calcite-Based Powder Materials Prepared by Planetary Ball Milling

    Directory of Open Access Journals (Sweden)

    Wen-Tien Tsai

    2013-08-01

    Full Text Available In this work, a planetary ball milling was used to modify the surface properties of calcite-based material from waste oyster shell under the rotational speed of 200600 rpm, grinding time of 5180 min and sample mass of 110 g. The milling significantly changed the microstructural properties of the calcite-based minerals (i.e., surface area, pore volume, true density, and porosity. The surface characterization of the resulting powder should be macroporous and/or nonporous based on the nitrogen adsorption/desorption isotherms. Under the optimal conditions at the rotational speed of 400 rpm, grinding time of 30 min and sample mass of 5 g, the resulting calcite-based powder had larger specific surface area (i.e., 10.64 m2g?1 than the starting material (i.e., 4.05 m2g?1. This finding was also consistent with the measurement of laser-diffraction (i.e., 9.7 vs. 15.0 ?m of mean diameter. In addition, the results from the scanning electron microscope (SEM observation indicated that surface roughness can be enhanced as particle size decreases as a result of particle-particle attrition. Thus, grinding the aquacultural bioresource by a high-energy ball milling can create the fine materials, which may be applied in the fields of inorganic minerals like aggregate and construction material.

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

    Directory of Open Access Journals (Sweden)

    R. ?wi?cik

    2009-12-01

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

  3. Research on automatic loading & unloading technology for vertical hot ring rolling process

    Directory of Open Access Journals (Sweden)

    Xiaokai Wang

    2015-01-01

    Full Text Available The automatic loading & unloading technology is the key to the automatic ring production line. In this paper, the automatic vertical hot ring rolling (VHRR process is taken as the target, the method of the loading & unloading for VHRR is proposed, and the mechanical structure of loading & unloading system is designed, The virtual prototype model of VHRR mill and loading & unloading mechanism is established, and the coordinated control method of VHRR mill and loading & unloading auxiliaries is studied, the movement trace and dynamic characteristic of the critical components are obtained. Finally, a series of hot ring rolling tests are conducted on the VHRR mill, and the production rhythm and the formed rings' geometric precision are analysed. The tests results show that the loading & unloading technology can meet the high quality and high efficiency ring production requirement. The research conclusions have practical significance for the large-scale automatic ring production.

  4. Rolling motion in moving droplets

    Indian Academy of Sciences (India)

    Sumesh P Thampi; Rama Govindarajan

    2015-03-01

    Drops moving on a substrate under the action of gravity display both rolling and sliding motions. The two limits of a thin sheet-like drop in sliding motion on a surface, and a spherical drop in roll, have been extensively studied. We are interested in intermediate shapes. We quantify the contribution of rolling motion for any intermediate shape, and recently obtained a universal curve for the amount of roll as a function of a shape parameter using hybrid lattice Boltzmann simulations. In this paper, we discuss the linear relationship which is expected between the Capillary and Bond numbers, and provide detailed confirmation by simulations. We also show that the viscosity of the surrounding medium can qualitatively affect dynamics. Our results provide an answer to a natural question of whether drops roll or slide on a surface and carry implications for various applications where rolling motion may or may not be preferred.

  5. FM Interviews: Stephanie Mills

    OpenAIRE

    Valauskas, Edward

    2002-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-08-01

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

  7. Characterization of the grinding behaviour in a single particle impact device: studies on pharmaceutical powders.

    Science.gov (United States)

    Meier, Matthias; John, Edgar; Wieckhusen, Dierk; Wirth, Wolfgang; Peukert, Wolfgang

    2008-05-10

    The grinding behaviour of different materials can be described by the two material parameters fMat and Wm,min [Vogel, L., Peukert, W., 2003. Breakage behaviour of different materials-construction of a mastercurve for the breakage probability. Powder Technol. 129, 101-110]. fMat describes the resistance of particulate material against fracture in impact comminution, Wm,min characterizes the specific energy which a particle can take up without comminution. The material parameters are determined experimentally by single particle impact tests. This concept is also applicable to pharmaceutical powders, as will be shown in this work. A device is presented for the characterization of particles with sizes down to a few 10 microm. Particles are dispersed and accelerated in an air stream which is flowing against an impact plate. The impact velocity is controlled by the air flow. An LDA system enables the measurement of particle velocities. The results obtained with this jet mill are in accordance to those obtained from another single particle impact device used by Vogel and Peukert, in which the influence of fluid flow is completely avoided. Since the new device is especially designed for finer powders, it will allow a more detailed analysis of the material parameters at smaller particle sizes. Additionally, a new analysis method has been developed in order to determine the breakage probability not from sieve analysis but from laser light diffraction (LLD) data by using a population balance. PMID:18400475

  8. Twin roll casting of magnesium alloys with high aluminum contents

    Directory of Open Access Journals (Sweden)

    H. Watari

    2006-08-01

    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 sheets 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 15C and 30C. Thecast strips should be hot rolled at 300C.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.

  9. Rolling Cylinder Phase 1

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Taraborrelli, Valeria Taraborrelli

    This report has been prepared under the contract agreement between Aalborg Universitet and Storper Innovation ApS. The report has been written by Lucia Margheritini (lm@civil.aau.dk ) who is also responsible for the data analysis. Laboratory tests in regular waves have been run by Lucia...... Margheritini and Valeria Taraborrelli(valeria.taraborrelli@hotmail.it) with a total of 3 day visit from the developers. Laboratory tests in irregular waves will be performed by Lucia Margheritini. The report is aimed at the first stage testing of the Rolling Cylinder wave energy device. This phase includes...... tests in regular waves and irregular waves, realized in two different set of tests....

  10. Evolution of topography and material removal during nanoscale grinding

    Science.gov (United States)

    Eder, S. J.; Cihak-Bayr, U.; Vernes, A.; Betz, G.

    2015-11-01

    In this work we perform molecular dynamics simulations to quantify and parametrize the evolution of a bcc Fe work piece topography during nanometric grinding with multiple hard abrasive particles. The final surface quality depends on both the normal pressure and the abrasive geometry. We fit the time development of the substrates root mean squared roughness to an exponential function, allowing the definition of a run-in regime, during which the surface forgets about its initial state, and a steady-state regime where the roughness no longer changes. The time constants associated with smoothing and material removal are almost inversely proportional to each other, highlighting the distinctiveness of these two simultaneously occurring processes. We also describe an attempt to reduce the time required to achieve the smoothest possible surface finish by periodically re-adjusting the normal pressure during the grinding process.

  11. Developments in Electrical Discharge Grinding process: A review

    Directory of Open Access Journals (Sweden)

    Dr. Govindan P*1,

    2014-04-01

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

  12. Results of the propagation behaviour and of grain analysis of machining residues when grinding materials of nuclear power station components

    International Nuclear Information System (INIS)

    Machining residues are formed during grinding on the grinding body/plant surface. These residues must be removed for reasons of activation, of keeping the plant clean and due to clogging up the structure and therefore negative grinding results. The results of investigations introduced are an important basis for possible removal variants directly at the plant surface/grinding body. (orig.)

  13. Control of Grinding Temperature by High Speed Air Jets

    OpenAIRE

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

    2004-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Yury GUTSALENKO

    2012-05-01

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

  15. Physical characterization of coffee after roasting and grinding

    Directory of Open Access Journals (Sweden)

    Gabriel Henrique Horta de Oliveira

    2014-09-01

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

  16. Rotary ultrasonic machining of CFRP: A comparison with grinding.

    Science.gov (United States)

    Ning, F D; Cong, W L; Pei, Z J; Treadwell, C

    2016-03-01

    Carbon fiber reinforced plastic (CFRP) composites have been intensively used in various industries due to their superior properties. In aircraft and aerospace industry, a large number of holes are required to be drilled into CFRP components at final stage for aircraft assembling. There are two major types of methods for hole making of CFRP composites in industry, twist drilling and its derived multi-points machining methods, and grinding and its related methods. The first type of methods are commonly used in hole making of CFRP composites. However, in recent years, rotary ultrasonic machining (RUM), a hybrid machining process combining ultrasonic machining and grinding, has also been successfully used in drilling of CFRP composites. It has been shown that RUM is superior to twist drilling in many aspects. However, there are no reported investigations on comparisons between RUM and grinding in drilling of CFRP. In this paper, these two drilling methods are compared in five aspects, including cutting force, torque, surface roughness, hole diameter, and material removal rate. PMID:26614168

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

    Directory of Open Access Journals (Sweden)

    A. Pribulov

    2010-04-01

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

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

    Directory of Open Access Journals (Sweden)

    H. Dyja

    2014-10-01

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

  19. Textures of molybdenum monocrystal deformation in rolling in profiled rolls

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    The rolling rolls quality has been enhanced mainly due to the improvements of the chemical compositions of rolls materials. The realization of an optimal chemical composition can constitute a technical efficient mode to assure the exploitation properties, the material from which the rolling mills rolls are manufactured having a higher importance in this sense. This paper continues to present the scientifically results of our experimental research in the area of the rolling rolls. The basic research contains concrete elements of immediate practical utilities in the metallurgical enterprises, for the quality improvements of rolls, having in last as the aim the durability growth and the safety in exploitation. This paper presents an analysis of the chemical composition, the influences upon the mechanical properties of the indefinite cast iron rolls. We present some mathematical correlations and graphical interpretations between the hardness (on the working surface and on necks) and the chemical composition. Using the double and triple correlations which is really helpful in the foundry practice, as it allows us to determine variation boundaries for the chemical composition, in view the obtaining the optimal values of the hardness. We suggest a mathematical interpretation of the influence of the chemical composition over the hardness of these indefinite rolling rolls. In this sense we use the multiple regression analysis which can be an important statistical tool for the 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.

  1. Compound taper milling machine

    Science.gov (United States)

    Campbell, N. R.

    1969-01-01

    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.

  2. Bay Mills' Bold Approach

    Science.gov (United States)

    Freedman, Eric

    2011-01-01

    It's a long, long way from Bay Mills Community College, near the shores of frigid Lake Superior, to Detroit. But distance, time and demographics aside, the school and the city are united by Bay Mills' status as the nation's only tribally controlled college that authorizes quasi-public schools, known officially as public school academies. And it's

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

    Science.gov (United States)

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

    2013-10-01

    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.

  4. Relationships of damaged starch granules and particle size distribution with pasting and thermal profiles of milled MR263 rice flour.

    Science.gov (United States)

    Asmeda, R; Noorlaila, A; Norziah, M H

    2016-01-15

    This research was conducted to investigate the effects of different grinding techniques (dry, semi-wet and wet) of milled rice grains on the damaged starch and particle size distribution of flour produced from a new variety, MR263, specifically related to the pasting and thermal profiles. The results indicated that grinding techniques significantly (psize distribution of rice flour. Wet grinding process yields flour with lowest percentage of starch damage (7.37%) and finest average particle size (8.52?m). Pasting and gelatinization temperature was found in the range of 84.45-89.63C and 59.86-75.31C, respectively. Dry ground flour attained the lowest pasting and gelatinization temperature as shown by the thermal and pasting profiles. Correlation analysis revealed that percentage of damaged starch granules had a significant, negative relationship with pasting temperature while average particle size distribution had a significant, strong negative relationship with gelatinization temperature. PMID:26258700

  5. 9 CFR 381.159 - Poultry rolls.

    Science.gov (United States)

    2010-01-01

    ...INSPECTION AND CERTIFICATION POULTRY PRODUCTS INSPECTION REGULATIONS...Composition 381.159 Poultry rolls. (a) Binders...permitted for use as binders in poultry rolls: transglutaminase enzyme...the product; e.g., Turkey Roll-Gelatin Added....

  6. Roll bonding of strained aluminium

    DEFF Research Database (Denmark)

    Staun, Jakob M.

    2003-01-01

    cross rolled volume fraction is found. To further asses this effect, and the anisotropy, it is necessary to acquire knowledge about both texture and microstructure, e.g. by TEM. Roll bonding of pre-strained aluminium is found to be a possible alternative to ARB in the quest for ultra-fine grained...

  7. Rolling friction of adhesive microspheres

    International Nuclear Information System (INIS)

    The rolling friction of adhesive microspheres is an important quantity as it determines the strength and stability of larger aggregates. Current models predict rolling forces that are 1 to 2 orders of magnitude smaller than observed experimentally. Starting from the well-known JohnsonKendallRoberts (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 0.1ms?1 and 110ms?1, respectively. (paper)

  8. Direct measures of mechanical energy for knife mill size reduction

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Tadisetti Premsai

    2014-07-01

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

  10. Rotordynamic Influence on Rolling ELement Bearing Selection and Operation

    Science.gov (United States)

    Queitzsch, Gilbert K., Jr.; Fleming, David P.

    2001-01-01

    Three case studies are presented that illustrate the importance of dynamic considerations in the design of machinery supported by rolling element bearings. The first case concerns a milling spindle that experienced internal rubs and high bearing loads, and required retrofit of an additional . damped bearing. The second case deals with a small high-speed generator that suffered high vibration due to flexible mounting. The third case is a propulsion fan simulator rig whose bearings failed catastrophically due to improper bearing installation (which resulted in inadequate dynamic bearing stiffness) and lack of health monitoring instrumentation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Eduardo Carlos Bianchi

    2003-06-01

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

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

    Scientific Electronic Library Online (English)

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

    2003-06-01

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

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

    Science.gov (United States)

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

    2013-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

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

    OpenAIRE

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

    2003-01-01

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

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

    OpenAIRE

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

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

    Rehder, Snke; Klukkert, Marten; Lbmann, Korbinian A. M.; Strachan, Clare J.; Sakmann, Albrecht; Gordon, Keith; Rades, Thomas; Leopold, Claudia S.

    2011-01-01

    Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e.,piracetam-citric acid and piracetam-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to prog...

  20. SYNTHESIS OF MODEL THE LUENBERGER OBSERVER FOR EXTERNAL CYLINDRICAL GRINDING PROCESS

    Directory of Open Access Journals (Sweden)

    Sergey BRATAN

    2013-05-01

    Full Text Available The problem of diagnosing the actual depth of cut at cylindrical grinding is considered.A mathematical model of the behavior of the grinding wheel and the workpiece during processingis worked out. According to this model it is produced a synthesis the model of the Luenbergerobserver with the Kalman filter to control the process of external cylindrical grinding. Thedeveloped approach is to improve the accuracy of control and the related with them computationalprocedures of assessment and management

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Phan Bui Khoi

    2015-03-01

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

  4. Effect of fiber orientations on surface grinding process of unidirectional C/SiC composites

    Science.gov (United States)

    Zhang, Lifeng; Ren, Chengzu; Ji, Chunhui; Wang, Zhiqiang; Chen, Guang

    2016-03-01

    The machining mechanism of woven ceramic matrix composites is one of the most challenging problems in composite application. To elucidate the grinding mechanism of the woven ceramic matrix composites, a new model material consisting of unidirectional CVI-C/SiC was prepared and ground. The composite was ground in three typical directions and the experimental investigation of the surface grinding process for this composite is described. In addition, the micro structural characteristics and grinding mechanism of the composite were analyzed. The result shows that brittle fracture is the dominant removal mechanism for grinding of the C/SiC composites, and the destroy form of the composites is mainly the syntheses of the matrix cracking, fiber fracture, and interfacial debonding. The grinding force follows the order: Normal > Longitudinal > Transverse, and the surface roughness follows: Longitudinal > Normal > Transverse. The grinding parameters (feed speed, cut depth, grinding speed) have great influence on the grinding force and surface roughness. Based on the findings, the grinding force and surface integrity of the woven ceramic matrix composites can be predicted. Furthermore, it is expected to provide a useful guideline for the design, evaluation and optimal application of the C/SiC composites.

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

    Directory of Open Access Journals (Sweden)

    Martin Novk

    2015-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Ondrej Jusko

    2012-01-01

    Full Text Available This paper focuses on the influence of various types of abrasive grains on cutting properties during the grinding process for bearing steel. In this experiment, not only conventional super-hard abrasive materials but also a new type of abrasive material were employed in grinding wheels. The measurement results were compared, and an evaluation was made of the cutting properties of the new abrasive material. The options were then evaluated for their practical applicability. The measurement results indicated that a grinding wheel with Abral and SG grains is the most suitable for grinding hardened bearing steel in order to achieve the best roughness and geometrical accuracy.

  7. Nano finish grinding of brittle materials using electrolytic in-process dressing (ELID) technique

    Indian Academy of Sciences (India)

    M Rahman; A Senthil Kumar; H S Lim; K Fatima

    2003-10-01

    Recent developments in grinding have opened up new avenues for finishing of hard and brittle materials with nano-surface finish, high tolerance and accuracy. Grinding with superabrasive wheels is an excellent way to produce ultraprecision surface finish. However, superabrasive diamond grits need higher bonding strength while grinding, which metal-bonded grinding wheels can offer. Truing and dressing of the wheels are major problems and they tend to glaze because of wheel loading. When grinding with superabrasive wheels, wheel loading can be avoided by dressing periodically to obtain continuous grinding. Electrolytic inprocess dressing (ELID) is the most suitable process for dressing metal-bonded grinding wheels during the grinding process. Nano-surface finish can be achieved only when chip removal is done at the atomic level. Recent developments of ductile mode machining of hard and brittle materials show that plastically deformed chip removal minimizes the subsurface damage of the workpiece. When chip deformation takes place in the ductile regime, a defect-free nano-surface is possible and it completely eliminates the polishing process. ELID is one of the processes used for atomic level metal removal and nano-surface finish. However, no proper and detailed studies have been carried out to clarify the fundamental characteristics for making this process a robust one. Consequently, an attempt has been made in this study to understand the fundamental characteristics of ELID grinding and their influence on surface finish.

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

    Science.gov (United States)

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

    2013-06-01

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

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

    Directory of Open Access Journals (Sweden)

    GHEORGHE VLAICU

    2010-06-01

    Full Text Available During the heating for rolling, ingots and billets are affected by the chemical action of the heating atmosphere. Between the heating environment elements and steel components there are taking place chemical reactions initiated at the separation surface that may affect a layer in metal of about a few microns to a few millimeters. The thickness of the affected layer is a function of the environment nature, heated material composition, chemical reactions 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.

  10. Mathematical models of homochiralisation by grinding of crystals

    CERN Document Server

    Wattis, Jonathan AD

    2010-01-01

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

  11. Mathematical models of the homochiralisation of crystals by grinding.

    Science.gov (United States)

    Wattis, Jonathan A D

    2011-04-01

    We review the existing mathematical models which describe physicochemical mechanisms capable of producing a symmetry-breaking transition to a state in which one chirality dominates the other. A new model is proposed, with the aim of elucidating the fundamental processes at work in the crystal grinding systems of Viedma (Phys Rev Lett 94:065504, 2005) and Noorduin (J Am Chem Soc 130:1158-1159, 2008). We simplify the model as far as possible to uncover the fundamental competitive process which causes the symmetry-breaking, and analyse other simplifications which might be expected to show symmetry-breaking. PMID:20683773

  12. Roll Control in Fruit Flies

    CERN Document Server

    Beatus, Tsevi; Cohen, Itai

    2014-01-01

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

  13. Rolling of tungsten base cermet in four-roll grooves

    International Nuclear Information System (INIS)

    The sintered cermet pieces 30 mm in diameter were used to roll square bars sized 32, 16 and 12 mm (the one-pass reduction ratio in the range 1.25-1.80). Studies were made of the contact stresses and energy parameters in the rolling of tungsten bars. The results obtained can be useful in the the design of new equipment and development of industrial technology

  14. Ball milling pretreatment of corn stover for enhancing the efficiency of enzymatic hydrolysis.

    Science.gov (United States)

    Lin, Zengxiang; Huang, He; Zhang, Hongman; Zhang, Lin; Yan, Lishi; Chen, Jingwen

    2010-11-01

    Ethanol can be produced from lignocellulosic biomass with the usage of ball milling pretreatment followed by enzymatic hydrolysis and fermentation. The sugar yields from lignocellulosic feed stocks are critical parameters for ethanol production process. The research results from this paper indicated that the yields of glucose and xylose were improved by adding any of the following dilute chemical reagents: H(2)SO(4), HCl, HNO(3), CH(3)COOH, HCOOH, H(3)PO(4), and NaOH, KOH, Ca(OH)(2), NH(3)H(2)O in the ball milling pretreatment of corn stover. The optimal enzymatic hydrolysis efficiencies were obtained under the conditions of ball milling in the alkali medium that was due to delignification. The data also demonstrated that ball milling pretreatment was a robust process. From the microscope image of ball milling-pretreated corn stover, it could be observed that the particle size of material was decreased and the fiber structure was more loosely organized. Meanwhile, the results indicate that the treatment effect of wet milling is better than that of dry milling. The optimum parameters for the milling process were ball speed of 350r/min, solid/liquid ratio of 1:10, raw material particle size with 0.5mm, and number of balls of 20 (steel ball, ??=?10mm), grinding for 30min. In comparison with water milling process, alkaline milling treatment could increase the enzymatic hydrolysis efficiency of corn stover by 110%; and through the digestion process with the combination of xylanase and cellulase mixture, the hydrolysis efficiency could increase by 160%. PMID:20593309

  15. Ion Milling of Sapphire

    Science.gov (United States)

    Gregory, Don A.; Herren, Kenneth A.

    2004-01-01

    The ion milling of sapphire is a complicated operation due to several characteristics of the material itself. It is a relatively hard transparent nonconductive crystalline material that does not transfer heat nearly as well as metals that have been successfully ion milled in the past. This investigation involved designing an experimental arrangement, using existing ion milling equipment, as the precursor to figuring the surface of sapphire and other insulating optical materials. The experimental arrangement employs a laser probe beam to constantly monitor the stresses being induced in the material, as it is being ion milled. The goal is to determine if the technique proposed would indeed indicate the stress being induced in the material so that these stresses can be managed to prevent failure of the optic.

  16. Optimization of hammer mills

    International Nuclear Information System (INIS)

    A simple mathematical model is proposed for the residence time distribution of crushed grain in hammer mills. The residence time distribution of the crushed grain, product quality, and the total energy consumption under various operation conditions (number of hammer rows, number of hammers in a row, mesh size of screen, velocity and output of the mill has been used as variables) was studied on a pilot hammer mill. The radiotracer was used for the experimental verification of the model and for the determination of a holdup (the magnitude of the rotating grist layer) on the pilot scale and partly also on the full-scale mills. The impulse responses were influenced by transport processes behind the screen. This effect had to be taken into account during the analysis of experimental data. The method of a non-linear regression analysis was applied for the evaluation of parameters of the mathematical model. (author)

  17. Manufacturing Demonstration Facility: Roll-to-Roll Processing

    Energy Technology Data Exchange (ETDEWEB)

    Datskos, Panos G [ORNL; Joshi, Pooran C [ORNL; List III, Frederick Alyious [ORNL; Duty, Chad E [ORNL; Armstrong, Beth L [ORNL; Ivanov, Ilia N [ORNL; Jacobs, Christopher B [ORNL; Graham, David E [ORNL; Moon, Ji Won [ORNL

    2015-08-01

    This Manufacturing Demonstration Facility (MDF)e roll-to-roll processing effort described in this report provided an excellent opportunity to investigate a number of advanced manufacturing approaches to achieve a path for low cost devices and sensors. Critical to this effort is the ability to deposit thin films at low temperatures using nanomaterials derived from nanofermentation. The overarching goal of this project was to develop roll-to-roll manufacturing processes of thin film deposition on low-cost flexible substrates for electronics and sensor applications. This project utilized ORNL s unique Pulse Thermal Processing (PTP) technologies coupled with non-vacuum low temperature deposition techniques, ORNL s clean room facility, slot dye coating, drop casting, spin coating, screen printing and several other equipment including a Dimatix ink jet printer and a large-scale Kyocera ink jet printer. The roll-to-roll processing project had three main tasks: 1) develop and demonstrate zinc-Zn based opto-electronic sensors using low cost nanoparticulate structures manufactured in a related MDF Project using nanofermentation techniques, 2) evaluate the use of silver based conductive inks developed by project partner NovaCentrix for electronic device fabrication, and 3) demonstrate a suite of low cost printed sensors developed using non-vacuum deposition techniques which involved the integration of metal and semiconductor layers to establish a diverse sensor platform technology.

  18. Preparation of magnesium ferrite nanoparticles by ultrasonic wave-assisted aqueous solution ball milling.

    Science.gov (United States)

    Chen, Ding; Li, Dian-yi; Zhang, Ying-zhe; Kang, Zhi-tao

    2013-11-01

    Magnesium ferrite, MgFe2O4 nanoparticles with high saturation magnetization were successfully synthesized using ultrasonic wave-assisted ball milling. In this study, the raw materials were 4MgCO3Mg(OH)25H2O and Fe2O3 powders and the grinding media was stainless steel ball. The average particle diameter of the product MgFe2O4 powders was 20 nm and the saturation magnetization of them reached 54.8 emu/g. The different results of aqueous solution ball milling with and without ultrasonic wave revealed that it was the coupling effect of ultrasonic wave and mechanical force that played an important role during the synthesis of MgFe2O4. In addition, the effect of the frequency of the ultrasonic wave on the ball milling process was investigated. PMID:23622867

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

    Energy Technology Data Exchange (ETDEWEB)

    Raj K. Rajamani

    2006-07-21

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Soulami, Ayoub [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Paxton, Dean M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burkes, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-04-23

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

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

    Scientific Electronic Library Online (English)

    Andreia Carolina, Rosa; Homero, Delboni Jr.

    2014-06-01

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

  2. petaja muutuv roll / Anneli Kannus

    Index Scriptorium Estoniae

    Kannus, Anneli

    2003-01-01

    Eesti Kutsehariduse Edendamise hingu ja haridusministeeriumi koosts toimus 2003.a. jaanuaris Phajrvel kutsehariduse talveseminar. hes trhmas arutleti teemal "petaja muutuv roll ja lesanded" ning tdeti, et kutsepetaja ettevalmistus ei vasta koolide ootustele.

  3. Frontal Impact of Rolling Spheres.

    Science.gov (United States)

    Domenech, A.; Casasus, E.

    1991-01-01

    A model of the inelastic collision between two spheres rolling along a horizontal track is presented, taking into account the effects of frictional forces at impact. This experiment makes possible direct estimates of the coefficients of restitution and friction. (Author)

  4. Rolling Resistance Measurement and Model Development

    DEFF Research Database (Denmark)

    Andersen, Lasse Grinderslev; Larsen, Jesper; Fraser, Elsje Sophia; Schmidt, Bjarne; Dyre, J. C.

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Bibler, J.E.

    1997-06-01

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

  6. Analysis on Large Deformation Compensation Method for Grinding Machine

    Directory of Open Access Journals (Sweden)

    Wang Ya-jie

    2013-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Foteini Kontoleontos

    2013-04-01

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

  8. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  9. Fundamentals of Rolling Contact Fatigue:

    OpenAIRE

    Grabulov, A.

    2010-01-01

    In the mechanical industry there is a need for continuous development towards increasing performance of various types of machinery. Critical components in such machines are exposed to gradually harsher operating environments involving higher cyclic stresses and operating temperatures. Examples of such fatigue-exposed components are gears, camshafts and rolling element bearings in engines and gearboxes. The components in the bearing industry are always subject to the high cycle rolling contact...

  10. Effects of high energy grinding under different atmospheres on the solubility of lithium in copper an pure copper

    International Nuclear Information System (INIS)

    The mechanical alloying process (MA) has successfully obtained supersaturated solid solutions in a great many binary systems. Increased solubility of over 90% compared to the maximum in equilibrium for the solutes Ag and Co and increases greater than 50% for Cr and Fe have been reported after using MA for the production of copper-based alloys. This has led to the development of much research to determine the maximum solubilities in solid state that can be reached with this process and for different solutes. Lithium is one of the elements investigated. Unlike other metallic elements, lithium has had, comparatively speaking, a recent introduction in the area of investigation of structural materials. The reason is simple, none of lithium's properties had been fundamental in this field until a little more than three decades ago. Lithium is an element with exceptional chemical and physical properties but due to its high reactivity, obtaining it complicates the operating conditions under which it is processed. The formation of a copper-based alloy with lithium has major theoretical advantages particularly relative to reducing the density of the copper-based alloy. However, these elements have other physical and chemical properties that complicate this development when using conventional alloying production processes, particularly those involving a fusion stage, so the use of mechanical alloying as an alternative process has been proposed. Besides developing in solid state, MA has proven to be particularly efficient in obtaining solid solutions of elements that, under conditions of equilibrium, show very limited or even no solubility. This work has studied the effects of two control atmospheres on the high energy grinding of Cu and Li and pure copper, as well as the effect of milling time for both atmospheres. The milling for this study was carried out in a SPEX 8000D mill using a balls to powder ratio of 10:1, with steel containers and balls. The milling times varied from 3 to 30 hours and the control atmospheres used were argon and nitrogen. The microstructural changes of the powders as a function of the variables studied, were analyzed with scanning electron microscopy on a Philips XL-30 SFEG. The phases present in the samples were analyzed using X-ray diffraction on a Siemens 5000 diffractometer. The iron quantities in the samples after milling, were determined with atomic adsorption spectroscopy in a GBS 905 spectrometer and the oxygen contents were determined with infrared spectroscopy on a LECO TC-436 DR. Results show a marked effect of the control atmosphere on the microstructural characteristics and chemical composition of the copper and on the chemical composition in the case of the Cu-Li alloys (cw)

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

    International Nuclear Information System (INIS)

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

  12. Approximate creep feed grinding of austempared ductile cast iron; Osutenpa kyujo kokuen chutetsu no kin`i kuripu fido kensaku

    Energy Technology Data Exchange (ETDEWEB)

    Nakamitsu, K.; Shimizu, K. [Oita National College of Technology, Oita (Japan)

    1996-10-01

    Austempered ductile cast iron (ADI) was subjected to approximate creep feed grinding to measure and observe the grinding ratio, hardness of ground surface, grinding resistance, production of burrs, roughness of ground surface, and grinding burn to investigate the best abrasive grains and grinding conditions. The grinding ratio of SiC grains was far better than that of Al2O3 grains, being about 10 times or more. Surface hardness of ADI ground by SiC grains changed little, but that ground by Al2O3 grains increased. As regards grinding resistance, that of Al2O3 grains have less slope and tangential component forces, but that of SiC grains increased with the increase in the ground volume. While burrs produced in grinding with SiC grains are secondary burrs, those produced in grinding with Al2O3 grains are primary burrs. In comparison with the normal grinding, grinding burn was produced on the ground surface, complicate striped patterns and grinding burns were produced by chattering particularly in grinding with Al2O3 grains. 10 refs., 11 figs., 2 tabs.

  13. A new model-based approach for power plant Tube-ball mill condition monitoring and fault detection

    International Nuclear Information System (INIS)

    Highlights: • This is the first mathematical model of power plant Tube-ball mills to cover the whole milling process. • A novel on-line model based power plant condition monitoring method is reported. • The online implementation of the model is achieved and the model was verified through online test. • The model parameters can be on-line updated/optimised using Genetic Algorithms. - Abstract: With the fast growth in intermittent renewable power generation, unprecedented demands for power plant operation flexibility have posed new challenges to the ageing conventional power plants in the UK. Adding biomass to coal for co-fired power generation has become widely implemented practices in order to meet the emission regulation targets. These have impacted the coal mill and power plant operation safety and reliability. The Vertical Spindle mill model was developed through the authors’ work before 2007. From then, the new research progress has been made in modelling and condition monitoring for Tube-ball mills and is reported in the paper. A mathematical model for Tube-ball milling process is developed by applying engineering principles combined with model unknown parameter identifications using a computational intelligent algorithm. The model describes the whole milling process from the mill idle status, start-up to normal grinding and shut-down. The model is verified using on-site measurement data and on-line test. The on-line model is used for mill condition monitoring in two ways: (i) to compare the predicted and measured mill output pressure and temperatures and to raise alarms if there are big discrepancies; and (ii) to monitor the mill model parameter variation patterns which detect the potential faults and mill malfunctions

  14. An investigation of the degradation products of coals with different degrees of grinding by mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zuhravlev, V.I.; Bychev, M.I.; Glushchenko, I.M.; Malevich, V.K.

    1983-01-01

    Investigations of the group chemical composition of the products of mechanodestruction liberated into the vapor phase from coals of various degrees of grinding have been made by the mass-spectrometric method. Some relationships have been found between the chemical composition of the volatile products liberated from the coals and the degrees of grinding of these coals.

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

    International Nuclear Information System (INIS)

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

  16. Thermal model to investigate the temperature in bone grinding for skull base neurosurgery.

    Science.gov (United States)

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

    2013-10-01

    This study develops a thermal model utilizing the inverse heat transfer method (IHTM) to investigate the bone grinding temperature created by a spherical diamond tool used for skull base neurosurgery. Bone grinding is a critical procedure in the expanded endonasal approach to remove the cranial bone and access to the skull base tumor via nasal corridor. The heat is generated during grinding and could damage the nerve or coagulate the blood in the carotid artery adjacent to the bone. The finite element analysis is adopted to investigate the grinding-induced bone temperature rise. The heat source distribution is defined by the thermal model, and the temperature distribution is solved using the IHTM with experimental inputs. Grinding experiments were conducted on a bovine cortical bone with embedded thermocouples. Results show significant temperature rise in bone grinding. Using 50C as the threshold, the thermal injury can propagate about 3mm in the traverse direction, and 3mm below the ground surface under the dry grinding condition. The presented methodology demonstrated the capability of being a thermal analysis tool for bone grinding study. PMID:23683875

  17. Thermal stabilization of uranium mill tailings

    International Nuclear Information System (INIS)

    The treatment of uranium mill tailings by high-temperature sintering (>10500C) has been investigated as a means of controlling the release of 222Rn and leachable contaminants. Thermal stabilization in laboratory trials at 12000C reduced the radon emanation of various tailings by factors ranging from 37 to 1400 depending on the mineralogy of the tailings. The leachability of most contaminants (e.g., Al, Cd, Mn, Pb, U, and Zn) was substantially reduced. The weathering of thermally stabilized tailings was simulated by grinding and leaching and appears dependent on the gypsum content and particle size distribution of the original tailings as well as the amount of amorphous material produced during thermal treatment. Pilot-scale thermal stabilization tests verified the technical feasibility of this conditioning process. A conceptual engineering design of a thermal stabilization operation has been developed around the use of coal-fired rotary cement kilns; economic analysis of remedial action alternatives at several inactive uranium processing sites indicates that the cost of thermal stabilization is comparable to relocating the tailings piles

  18. EVOLUTION OF THE AUSTENITE GRAIN SIZE DURING HOT STRIP ROLLING OF NIOBIUM MICROALLOYED STEELS

    Directory of Open Access Journals (Sweden)

    Antonio Augusto Gorni

    2015-06-01

    Full Text Available The occurrence of dynamic recrystallization in the intermediate stands of the Finishing Mill of a Hot Strip Mill promotes substantial softening of the rolling stock, a situation that can cause operational problems and even scrapping of the strip. The aim of this work was to identify the specific process conditions that can lead to this situation, which was carried out through the application of a microstructural evolution model. It was verified, for the specific conditions of the Cubatão Works of Usiminas, that this problem generally occurs during the processing of thin hot coils, with a relatively low Nb content and under rolling temperatures slightly lower than the normal range.

  19. Preparation of glibenclamide nanocrystals by a simple laboratory scale ultra cryo-milling

    International Nuclear Information System (INIS)

    The objective of this study is to evaluate the ability to reduce the particle size of glibenclamide (GBC) to the nanometric scale through a very simple and well-known laboratory scale method, the laboratory scale ultra cryo-milling. The effect of milling on GBC crystalline properties and dissolution behaviour was deliberately evaluated in the absence of any surfactants as stabilizers. The milling procedure consisted in adding particles to liquid nitrogen and milling them by hand in a mortar with a pestle for different time intervals (15, 30, 40 min). For comparison, the same milling procedure was also applied without liquid nitrogen. The particle size reduction was evaluated for the coarsest samples (>3 ?m) by measuring the particle Ferrets diameter through scanning electron microscopy, while for the smallest one (<3 ?m) by dynamic light scattering. A time grinding of 40 min in the presence of liquid nitrogen was revealed highly efficacious to obtain particles of nanodimensions, with a geometric mean particle size of 0.55 0.23 ?m and more than the 80 % of particles lower than 1,000 nm. Interestingly, non-agglomerated particles were obtained. Differential scanning calorimetry and X-ray powder diffractometry allowed to assess that under mechanical treatment no polymorphic transitions were observed, while a decrease in crystallinity degree occurred depending on the milling procedure (presence or absence of liquid nitrogen) and the milling time (crystallinity decreases at increasing milling time from 15 to 40 min). A comparison of the intrinsic dissolution rate and the dissolution from particles revealed an interesting improvement of particle dissolution particularly for particles milled in the presence of liquid nitrogen due to an increase in particle surface area and concentration gradient, according to the NoyesWhitney equation.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e.,piracetam-citric acid and piracetam......-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to progress via an amorphous intermediate stage, which was more evident for the piracetam-citric acid than for...... the piracetam-tartaric acid cocrystal. It was shown that liquid-assisted grinding led to faster cocrystal formation than dry grinding, which may be explained by the higher transformation rate due to the presence of liquid. The cocrystal formation rate did not depend on the applied polymorphic form of...

  1. Study on grinding of free-form optics surface in three-axis CNC machine

    Science.gov (United States)

    Yang, Haicheng; Zhang, Yun-long; Zhang, Feng; Wang, Zhibin; Bao, Long-xiang; Su, Ying; Guo, Rui; Liu, Xuan-min

    2014-08-01

    Due to the glass is a type of brittle material, so the high-precision free-form optics of glass material is usually machined by the technical of grinding. In this paper, for the characteristics of the diamond grinding wheel, analyzing the grinding path of free-form optics and mathematical model of the path is established based on the three-axis CNC grinding device. Moreover, the cause of the interference in the process of grinding is analyzed and the methods of avoiding. Finally, based on the above analysis results, through the experiment, the free-form optics surface accuracy was reached to 3.6um, realize the machining of the free-form optics.

  2. Chemistry and structure of coals: Effects of grinding media on a subbituminous coal

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, E.L. Jr.

    1990-01-01

    Coal preparation techniques used to provide feedstocks for direct utilization in combustion facilities require extensive grinding. Separation of noxious elements (mineral matter, sulfur, nitrogen, etc.) is facilitated by grinding. Current and future needs for clean air require that more complete separation be carried out. Chemical cleaning processes can be combined and carried out simultaneously by incorporation of chemicals in the grinding media. This work has shown that the argillic mineral matter hydrolyzes in aqueous grinding media and the hydrolysis is markedly enhanced in alkaline media. Direct incorporation of carbon dioxide is accomplished in the alkaline media to form ketone and acid salt groups on the surface of subbituminous coal particles. Diffuse reflectance infrared spectroscopy has been shown to be an excellent aid in defining the chemical and physical changes induced in the grinding process. 8 refs., 12 figs.

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

    Directory of Open Access Journals (Sweden)

    Keith Gordon

    2011-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Raju S. Pawade

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Grdulska A.

    2014-10-01

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

  6. Vertical multi-plane grinding machine SAR60; Tatejiku tamen kensakuban SAR60

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-04-20

    This is a small and highly accurate machine of the vertical spindle multi-plane grinding machine SAR series. The purpose of the machine is to grind with ultra-accuracy inner/outer/end faces of ceramics, new materials, etc. The main specifications are as follows. Maximum grinding outer diameter: 600mm. Maximum processing height: 400mm. Grinding wheel spindle drive use motor: AC5.5/7.5kW. NC controller: FANUC 18i-T. The features are as follows. (1) The setting of a grinding head up/down and right/left cancels errors of accuracy such as thermal displacement by the scale feedback control. (2) The automatic exchange of grinder made the automatic operation from rough processing to finish processing possible. (3) The dressing of diamond wheel on the machine was made possible by rotary dresser. (translated by NEDO)

  7. The effect of roll gap geometry on microstructure in cold-rolled aluminum

    DEFF Research Database (Denmark)

    Mishin, Oleg; Bay, B.; Winther, G.; Juul Jensen, D.

    2004-01-01

    Microstructure and texture are analyzed through the thickness of two aluminum plates cold-rolled 40% with different roll gap geometries. It is found that both texture and microstructure are strongly affected by the rolling geometry. After rolling with intermediate-size draughts a rolling-type texture is developed throughout the plate thickness. In this case, grains are subdivided by extended planar dislocation boundaries preferentially aligned at an angle of 40 +/- 15degrees to the rolling direc...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-02-01

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

  9. High-precision thickness setting models for titanium alloy plate cold rolling without tension

    Science.gov (United States)

    Wang, Xiaochen; Yang, Quan; He, Fei; Sun, Youzhao; Xiao, Huifang

    2015-03-01

    Due to its highly favorable physical and chemical properties, titanium and titanium alloy are widely used in a variety of industries. Because of the low output of a single batch, plate cold rolling without tension is the most common rolling production method for titanium alloy. This method is lack of on-line thickness closed-loop control, with carefully thickness setting models for precision. A set of high-precision thickness setting models are proposed to suit the production method. Because of frequent variations in rolling specification, a model structural for the combination of analytical models and statistical models is adopted to replace the traditional self-learning method. The deformation resistance and friction factor, the primary factors which affect model precision, are considered as the objectives of statistical modeling. Firstly, the coefficient fitting of deformation resistance analytical model based on over-determined equations set is adopted. Additionally, a support vector machine(SVM) is applied to the modeling of the deformation resistance and friction factor. The setting models are applied to a 1450 plate-coiling mill for titanium alloy plate rolling, and then thickness precision is found consistently to be within 3%, exceeding the precision of traditional setting models with a self-learning method based on a large number of stable rolling data. Excellent application performance is obtained. The proposed research provides a set of high-precision thickness setting models which are well adapted to the characteristics of titanium alloy plate cold rolling without tension.

  10. Mathematical simulation of controlled cooling for high speed rolled wire in Stelmor process

    International Nuclear Information System (INIS)

    Mathematical models have been developed to predict the temperature distribution and austenite - pearlite transformation kinetics during the processing of high carbon steel wire in a stelmor machine. For a given rod radius there are three critical fans whose mechanical efficiency should be periodically reviewed to maintain constant cooling condition. These models are currently being applied for rod production control at the transformation at the conveyor of Tangshan Iron and Steel Co. Ltd., High Speed Wire Rod Rolling Mill, China. (author)

  11. [Reduction of dust during manual grinding of cast iron].

    Science.gov (United States)

    Gli?ski, Maciej

    2002-01-01

    The method for determining the emission of dust and the effectiveness of dust removal from machines and devices by local exhaust ventilation to the workplace air is presented. This method consists in determining concentrations of air pollution in the measuring duct through which it is sucked off from the chambers with tested devices. At the same time the volume of air flow rate is measured. A laser dust analyzer is used to measure dust concentrations in the air. Air is sampled with isokinetic sampling heads. It was shown that dust emission at different kinds of manual grinding of cast iron without ventilation was between 24 mg/min and 8131 mg/min, whereas with the use of local exhaust ventilation it decreased below 35 mg/min. The efficiency of the exhaust elements was over 95% at optimum use of local ventilation. PMID:12051159

  12. Pyrolysis of a waste from the grinding of scrap tyres.

    Science.gov (United States)

    Fernndez, A M; Barriocanal, C; Alvarez, R

    2012-02-15

    The fibres that are used to reinforce tyres can be recovered as a waste in the process of grinding of scrap tyres. In this paper beneficiation through pyrolysis is studied since the fibres are made up of polymers with a small amount of rubber because the latter is difficult to separate. The experiments were performed at three temperatures (400, 550 and 900C) in a horizontal oven. The three products - gas, oil and char - obtained from the pyrolysis were investigated. The composition of the gas was analyzed by means of gas chromatography. The oil was studied by gas chromatography and infrared spectroscopy. The char porous structure was determined by N(2) adsorption. In addition, the topography of the chars was studied by means of scanning electron microscopy (SEM). The products resulting from the pyrolysis of the fibres were compared with those obtained from scrap rubber. PMID:22204837

  13. Nano surface generation of grinding process using carbon nano tubes

    Indian Academy of Sciences (India)

    S Prabhu; B K Vinayagam

    2010-12-01

    Nano surface finish has become an important parameter in the semiconductor, optical, electrical and mechanical industries. The materials used in these industries are classified as difficult to machine materials such as ceramics, glasses and silicon wafers. Machining of these materials up to nano accuracy is a great challenge in the manufacturing industry. Finishing of micro components such as micro-moulds, micro-lenses and micro-holes need different processing techniques. Conventional finishing methods used so far become almost impossible or cumbersome. In this paper, a nano material especially multi wall carbon nano tube is used in the machining process like grinding to improve the surface characteristics from micro to nano level.

  14. Ambient roll-to-roll fabrication of flexible solar cells based on small molecules

    DEFF Research Database (Denmark)

    Lin, Yuze; Dam, Henrik Friis; Andersen, Thomas Rieks; Bundgaard, Eva; Fu, Weifei; Chen, Hongzheng; Krebs, Frederik C; Zhan, Xiaowei

    2013-01-01

    All solution-processed roll-to-roll flexible solar cells based on a starshaped small molecule donor and PCBMacceptor were fabricated by slot-die coating, as the first successful example reported for small molecule roll-to-roll flexible solar cells.......All solution-processed roll-to-roll flexible solar cells based on a starshaped small molecule donor and PCBMacceptor were fabricated by slot-die coating, as the first successful example reported for small molecule roll-to-roll flexible solar cells....

  15. Diseo y Evaluacin Energtica de dos Circuitos de Molienda y Clasificacin para un Clinker de Cemento a Escala Piloto Design and Energy Evaluation of two Grinding and Classifier Circuits of a Pilot Scale Cement Clinker

    Directory of Open Access Journals (Sweden)

    Adriana M Osorio

    2013-01-01

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

  16. Diseo y Evaluacin Energtica de dos Circuitos de Molienda y Clasificacin para un Clinker de Cemento a Escala Piloto / Design and Energy Evaluation of two Grinding and Classifier Circuits of a Pilot Scale Cement Clinker

    Scientific Electronic Library Online (English)

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

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

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

    Science.gov (United States)

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2013-09-01

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

  20. Online monitoring and control of particle size in the grinding process using least square support vector regression and resilient back propagation neural network.

    Science.gov (United States)

    Pani, Ajaya Kumar; Mohanta, Hare Krishna

    2015-05-01

    Particle size soft sensing in cement mills will be largely helpful in maintaining desired cement fineness or Blaine. Despite the growing use of vertical roller mills (VRM) for clinker grinding, very few research work is available on VRM modeling. This article reports the design of three types of feed forward neural network models and least square support vector regression (LS-SVR) model of a VRM for online monitoring of cement fineness based on mill data collected from a cement plant. In the data pre-processing step, a comparative study of the various outlier detection algorithms has been performed. Subsequently, for model development, the advantage of algorithm based data splitting over random selection is presented. The training data set obtained by use of Kennard-Stone maximal intra distance criterion (CADEX algorithm) was used for development of LS-SVR, back propagation neural network, radial basis function neural network and generalized regression neural network models. Simulation results show that resilient back propagation model performs better than RBF network, regression network and LS-SVR model. Model implementation has been done in SIMULINK platform showing the online detection of abnormal data and real time estimation of cement Blaine from the knowledge of the input variables. Finally, closed loop study shows how the model can be effectively utilized for maintaining cement fineness at desired value. PMID:25528293

  1. Effect of feed grinding methods with and without expansion on prececal and total tract mineral digestibility as well as on interior and exterior egg quality in laying hens.

    Science.gov (United States)

    Hafeez, A; Mader, A; Ruhnke, I; Mnner, K; Zentek, J

    2016-01-01

    The grinding of cereals by various milling methods as well as thermal treatment of feed may influence mineral digestibility and egg quality. The present study investigated the effect of feed produced by disc mill (D) and wedge-shaped disc mill (WSD), as mash (M) or expandate (E) on apparent ileal absorption (AIA) and apparent total digestibility (ATD) of calcium, phosphorus, magnesium, zinc, manganese, copper and iron, as well as on egg quality in laying hens. A total of 192 hens (Lohmann Brown) aged 19 wk, were assigned using a randomized design with a 2 2 factorial arrangement. Four experimental diets were offered ad libitum. Eggs were analyzed for weight, shape index, area, shell weight per unit surface area, yolk color, air cell, blood spot, Haugh unit, albumen and yolk measures (index, weight, height, width and length), shell measures (surface area, stability, density, thickness and membrane weight), as well as percent contents of albumen, yolk, shell, and shell membrane. The ATD for phosphorus, manganese, and copper was higher in WSD compared with D treatment (P = 0.028, P = 0.028 and P = 0.016, respectively). The interaction between milling methods and thermal treatment influenced ATD of copper (P = 0.033), which was higher in WSD+M group (41.0 20.2) compared with D+E group (-3.21 25.1), whereas no differences were observed for D+M (1.90 37.8) and WSD+E (8.02 36.2) groups. Egg stability tended to be higher in E compared with M treatment (P = 0.055). Albumen weight, percentage albumen weight, and albumen: yolk were higher and percentage yolk weight was lower in D compared with WSD treatment (P = 0.043, P = 0.027, P = 0.024, and P = 0.041, respectively). Number of blood spots was higher in E than M treatment (P = 0.053). In conclusion, use of a wedge-shaped disc mill resulted in higher ATD for phosphorus, manganese, and copper than use of a disc mill; however, digestibility for majority of minerals as well as egg quality parameters was comparable. Therefore, feed produced by either disc mill or wedge-shaped disc mill as mash or expandate may be used for laying hens without negative effects on egg quality. PMID:26574028

  2. The effects of particle size, milling method, and thermal treatment of feed on performance, apparent ileal digestibility, and pH of the digesta in laying hens.

    Science.gov (United States)

    Ruhnke, Isabelle; Rhe, Ilen; Krmer, Carolin; Goodarzi Boroojeni, Farshad; Knorr, Fanny; Mader, Anneluise; Schulze, Erin; Hafeez, Abdul; Neumann, Konrad; Lwe, Rainer; Zentek, Jrgen

    2015-04-01

    Various milling methods result in different particle size distributions and, in combination with mash and thermal treatment (expandate) of the feed, may have an impact on nutrient digestibility, pH of the digesta and subsequently the performance of an animal. Since this aspect has not been widely considered in laying hens, the objective of the present study was to investigate the effects of milling method, expansion, and particle size of feed on performance, apparent ileal nutrient digestibility, and pH of digesta in laying hens. Twelve variants of the same diet were produced. Four different milling techniques (hammer mill, roller mill, disc mill, and wedge-shaped disc mill) were used to grind the feed cereals. Coarse feed was obtained from all four mills. Additionally, fine feed was obtained from the hammer mill and the roller mill. Each of the six feed variants was offered as mash or expandate, resulting in a total of 12 treatments. The duration of the experimental period was 21 days. A total of 576 layers, each 19 weeks of age, were used in eight replicates. The statistical analysis for the four milling methods and two thermal treatments was performed using a 42 factorial arrangement. The effect of particle size was investigated using a 222 factorial arrangement including the coarse and fine particle sizes that were produced with the hammer mill and the roller mill as well as the mash and expandate. The animal performance and the pH of the digesta were not affected by the treatments. Ileal digestibility of starch was significantly improved by feeding mash compared to expandate (P=0.013) and by feeding coarse compared to fine feed (P=0.028). Based on this study, the tested milling methods can be used for the production of feed for laying hens without affecting performance and digestibility of nutrients. PMID:25717083

  3. Hot rolling of thick uranium molybdenum alloys

    Energy Technology Data Exchange (ETDEWEB)

    DeMint, Amy L.; Gooch, Jack G.

    2015-11-17

    Disclosed herein are processes for hot rolling billets of uranium that have been alloyed with about ten weight percent molybdenum to produce cold-rollable sheets that are about one hundred mils thick. In certain embodiments, the billets have a thickness of about 7/8 inch or greater. Disclosed processes typically involve a rolling schedule that includes a light rolling pass and at least one medium rolling pass. Processes may also include reheating the rolling stock and using one or more heavy rolling passes, and may include an annealing step.

  4. Yang-Mills and Beyond

    OpenAIRE

    Marateck, Samuel

    2011-01-01

    In their 1954 paper, Yang and Mills invented the non-Abelian field strength to satisfy certain criteria but didn't explain how it could be derived. In the penultimate section we show how the Yang-Mills field strength derives from Yang's gauge transformation. The preceding sections place Yang-Mills theory in historical perspective and cover material relating to the field strength. The final section shows how Yang-Mills theory was combined with spontaneous symmetry breaking, t...

  5. Evaluating the mechanical behavior of hot rolled Al/alumina composite strips using shear punch test

    International Nuclear Information System (INIS)

    The evaluation of mechanical properties, like yield and ultimate shear strengths from shear punch tests, is important when availability of material, is limited. A shear punch test setup was built, and the mechanical properties of different strips of hot rolled pure aluminum, post-rolling annealed pure aluminum, as-milled pure aluminum, and 4 wt% Al2O3 were investigated. The materials were first manufactured using powder metallurgy and then processed by hot rolling procedure. Microstructures of the samples were investigated by optical and scanning electron microscopes. It was found that by increasing alumina content in the matrix, shear strength and hardness were increased; also, the percentage of shear elongation was decreased. The results, also, indicated that by applying mechanical milling on pure aluminum powders before the hot rolling process, shear strength and hardness increased more than other samples. Moreover, shear strength was increased by increasing the amount of alumina particles in composite strips. SEM observations demonstrated that the amount of flat surface in shear failure micrographs increased by increasing the amount of shear strength and hardness

  6. Influence of nanomechanical crystal properties on the comminution process of particulate solids in spiral jet mills.

    Science.gov (United States)

    Zgner, Sascha; Marquardt, Karin; Zimmermann, Ingfried

    2006-02-01

    Elastic-plastic properties of single crystals are supposed to influence the size reduction process of bulk materials during jet milling. According to Pahl [M.H. Pahl, Zerkleinerungstechnik 2. Auflage. Fachbuchverlag, Leipzig (1993)] and H. Rumpf: [Prinzipien der Prallzerkleinerung und ihre Anwendung bei der Strahlmahlung. Chem. Ing. Tech., 3(1960) 129-135.] fracture toughness, maximum strain or work of fracture for example are strongly dependent on mechanical parameters like hardness (H) and young's modulus of elasticity (E). In addition the dwell time of particles in a spiral jet mill proved to correlate with the hardness of the feed material [F. Rief: Ph. D. Thesis, University of Wrzburg (2001)]. Therefore 'near-surface' properties have a direct influence on the effectiveness of the comminution process. The mean particle diameter as well as the size distribution of the ground product may vary significantly with the nanomechanical response of the material. Thus accurate measurement of crystals' hardness and modulus is essential to determine the ideal operational micronisation conditions of the spiral jet mill. The recently developed nanoindentation technique is applied to examine subsurface properties of pharmaceutical bulk materials, namely calcite, sodium ascorbate, lactose and sodium chloride. Pressing a small sized tip into the material while continuously recording load and displacement, characteristic diagrams are derived. The mathematical evaluation of the force-displacement-data allows for calculation of the hardness and the elastic modulus of the investigated material at penetration depths between 50-300 nm. Grinding experiments performed with a modified spiral jet mill (Type Fryma JMRS 80) indicate the strong impact of the elastic-plastic properties of a given substance on its breaking behaviour. The fineness of milled products produced at constant grinding conditions but with different crystalline powders varies significantly as it is dependent on the nanohardness and the elasticity of the feed material. The analysis of this correlation gives new insights into the size reduction process. PMID:16202574

  7. Controlled wear of vitrified abrasive materials for precision grinding applications

    Indian Academy of Sciences (India)

    M J Jackson; B Mills; M P Hitchiner

    2003-10-01

    The study of bonding hard materials such as aluminium oxide and cubic boron nitride (BN) and the nature of interfacial cohesion between these materials and glass is very important from the perspective of high precision grinding. Vitrified grinding wheels are typically used to remove large volumes of metal and to produce components with very high tolerances. It is expected that the same grinding wheel is used for both rough and finish machining operations. Therefore, the grinding wheel, and in particular its bonding system, is expected to react differently to a variety of machining operations. In order to maintain the integrity of the grinding wheel, the bonding system that is used to hold abrasive grains in place reacts differently to forces that are placed on individual bonding bridges. This paper examines the role of vitrification heat treatment on the development of strength between abrasive grains and bonding bridges, and the nature of fracture and wear in vitrified grinding wheels that are used for precision grinding applications.

  8. Modelling of fracture wear in vitrified cBN grinding wheels

    Directory of Open Access Journals (Sweden)

    M.J. Jackson

    2007-09-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  10. Effect of surface shear on cube texture formation in heavy cold-rolled Cu-45 at%Ni alloy substrates

    DEFF Research Database (Denmark)

    Tian, Hui; Suo, Hongli

    2015-01-01

    Two types of Cu-45 at%Ni alloy thin tapes with and without surface shear were obtained by different heavy cold rolling processes. The deformation and recrystallization textures of the two tapes were thoroughly investigated by electron back scattering diffraction technique. The results showed that a shear texture mainly covered the surface of the heavy deformed tapes because of the fraction between the surface of rolling mills and the thin tapes when the rolling force strongly reduced at high strain, which significantly reduced the fraction of rolling texture on the surface of the Cu-45at %Ni alloy thin tapes, retarded the cube grain growth during recrystallization and affected the strong cube texture formation after high temperature annealing.

  11. Interim report on task 1.2: near equilibrium processing requirements - attrition milling part 1 of 2 to Lawrence Livermore National for contract b345772

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, M W A; Vance, E R; Day, R A; Eddowes, T; Moricca, S

    2000-04-30

    The objective of Task 1.2 has only partly been achieved as the work on Pu/U-formulations and to a significant degree on Th/U-formulations has been performed under grinding/blending conditions that did not replicate plant-like fabrication processes, particularly in the case with the small glovebox attritor. Nevertheless the results do show that actinide-rich particles, not present in specimens made via the alkoxide-route (equilibrium conditions), occur when the grinding process is not efficient enough to ensure that high-fired PuO{sub 2}, ThO{sub 2} and UO{sub 2} particles are below a critical size. Our current perception is that the critical size for specimens sintered at 1350 C for 4 hours is about 5 {micro}m in diameter. The critical size is difficult to estimate, as it is equal to the starting diameter of actinide oxides just visible within brannerite regions. Our larger scale attritor experiments as well as experience with wet and dry ball milling suggests that acceptable mineralogy and microstructure can be obtained by dry milling via attritor and ball mills. This is provided that appropriate attention is paid to the size and density of the grinding media, grinding additives that reduce caking of the powder, and in the case of attritors the grinding speed and pot setup. The ideal products for sintering are free flowing granules of {approx} 100 {micro}m containing constituents ground to about 1 {micro}m to ensure homogeneity and equilibrium mineralogy.

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

    Science.gov (United States)

    Miho, Otoaki; Sato, Toru; Matsukubo, Takashi

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Lszl Forr

    2013-09-01

    Full Text Available The statistical analysis of the length distribution of catalytic chemical vapour deposition synthesized multi-walled carbon nanotubes cut by planetary ball milling is reported. The nanotube lengths follow a log-normal distribution in a broad range of grinding time and rotational speed. We show that the scale parameter of the distribution, which equals the mean of the natural logarithm of the tube lengths, decreases linearly with the product of the duration time and the rotational speed. This relation can be used for tailoring nanotube lengths by a suitable choice of process parameters for a wide range of applications.

  14. Cell sorting by deterministic cell rolling

    OpenAIRE

    Choi, Sungyoung; Karp, Jeffrey M.; Karnik, Rohit

    2012-01-01

    This communication presents the concept of deterministic cell rolling, which leverages transient cell-surface molecular interactions that mediate cell rolling to sort cells with high purity and efficiency in a single step.

  15. Effect of bead milling on chemical and physical characteristics of activated carbons pulverized to superfine sizes.

    Science.gov (United States)

    Partlan, Erin; Davis, Kathleen; Ren, Yiran; Apul, Onur Guven; Mefford, O Thompson; Karanfil, Tanju; Ladner, David A

    2016-02-01

    Superfine powdered activated carbon (S-PAC) is an adsorbent material with particle size between roughly 0.1-1?m. This is about an order of magnitude smaller than conventional powdered activated carbon (PAC), typically 10-50?m. S-PAC has been shown to outperform PAC for adsorption of various drinking water contaminants. However, variation in S-PAC production methods and limited material characterization in prior studies lead to questions of how S-PAC characteristics deviate from that of its parent PAC. In this study, a wet mill filled with 0.3-0.5mm yttrium-stabilized zirconium oxide grinding beads was used to produce S-PAC from seven commercially available activated carbons of various source materials, including two coal types, coconut shell, and wood. Particle sizes were varied by changing the milling time, keeping mill power, batch volume, and recirculation rate constant. As expected, mean particle size decreased with longer milling. A lignite coal-based carbon had the smallest mean particle diameter at 169nm, while the wood-based carbon had the largest at 440nm. The wood and coconut-shell based carbons had the highest resistance to milling. Specific surface area and pore volume distributions were generally unchanged with increased milling time. Changes in the point of zero charge (pHPZC) and oxygen content of the milled carbons were found to correlate with an increasing specific external surface area. However, the isoelectric point (pHIEP), which measures only external surfaces, was unchanged with milling and also much lower in value than pHPZC. It is likely that the outer surface is easily oxidized while internal surfaces remain largely unchanged, which results in a lower average pH as measured by pHPZC. PMID:26657354

  16. Microstructure and martensitic transformation in Si-coated TiNi powders prepared by ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-hyun; Cho, Gyu-bong; Im, Yeon-min [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Chun, Byong-sun [ReSEAT Program, KISTI, Daejeon 305-806 (Korea, Republic of); Kim, Yeon-wook [Department of Advanced Materials Engineering, Keimyung University, 1000 Shindang-dong, Dalseo-gu, Daegu 704-701 (Korea, Republic of); Nam, Tae-hyun, E-mail: tahynam@gnu.ac.kr [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of)

    2013-12-15

    Graphical abstract: - Highlights: Amorphous Si-coated TiNi powders were prepared successfully by ball milling. Ti{sub 4}Ni{sub 4}Si{sub 7} was formed at the interface between Si and TiNi after annealing. Si-coated TiNi powders displayed the R phase after annealing. - Abstract: Si was coated on the surface of Ti49Ni (at%) alloy powders by ball milling in order to improve the electrochemical properties of the Si electrodes of secondary Li ion batteries and then the microstructure and martensitic transformation behavior were investigated by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). TiNi powders coated with Si were fabricated successfully by ball milling. As-milled powders consisted of highly deformed TiNi powders with the B2 phase and amorphous Si layers. The thickness of the Si layer coated on the surface of the TiNi powders increased from 35 ?m to 1015 ?m by extending the milling time from 3 h to 48 h. However, severe contamination from the grinding media, ZrO{sub 2} occurred when the ball milling time was as long as 48 h. By heating as-milled powders to various temperatures in the range of 673873 K, the highly deformed TiNi powders were recovered and Ti{sub 4}Ni{sub 4}Si{sub 7} was formed. Two-stage B2RB19? transformation occurred when as-milled Si-coated Ti49Ni alloy powders were heated to temperatures below 873 K, above this temperature one-stage B2B19? transformation occurred.

  17. Effect of milling temperature and post-milling cooling procedures on rice milling quality appraisals

    Science.gov (United States)

    The objective of this research was to study the effects of different milling conditions and post-milling handling procedures on appraised milling quality of rough rice. Samples of medium grain rough rice (M202) with moisture content (MC) of 11.50.2% were used for this study. To create different mil...

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

    Directory of Open Access Journals (Sweden)

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

    2009-03-01

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

  19. Optimization of Metal Removal Rateon Cylindrical Grinding For Is 319 Brass Using Taguchi Method

    Directory of Open Access Journals (Sweden)

    Gaurav Upadhyay

    2015-06-01

    Full Text Available Cylindrical grinding is one of the most important metal cutting processes used extensively in the Metal finishing operations. Metal removal rate and surface finish are the important output responses in the production with respect to quantity and quality respectively. The objective of this paper is to arrive at the optimal grinding conditions that will maximize metal removal rate when grinding IS 319 brass. Empirical models were developed using design of experiments by Taguchi L9 Orthogonal Array and the adequacy of the developed model is tested with ANOVA.

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

    OpenAIRE

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

    1999-01-01

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