The rolling consists in billet compressing between the rotating rolls. The billet retracts between the rollers by friction forces, and the pressure forces reduce the transverse billet dimensions. The pressure forces are normal to the rolls surface. There are three main types of rolling: longitudinal, transverse and cross- helical. The longitudinal rolling. The billet deformed between two rolls rotating in different directions, and moves perpendicular to the rolls axes. The flat billet produces this way. The transverse rolling. The rolls rotate in the same direction and impart the billet rotation. The billet moving along to the rolls axis and deforms. In this rolling way obtains the billet in the form of revolution body. The cross-helical rolling. The rolls located at an angle and report to the billet the rotational and translational motion during it deformation. In this rolling way obtains the billet with complex shapes. The rolling product profile is the shape of its cross-section. The profiles set of different sizes called a range. The rolling profiles range divided into 4 main groups: long products, sheets, pipes and special types of rolled metal. Long products profiles divided into simple shapes and complex shapes. Simple shapes are square, circle, hexahedron and […]
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The metals treatment by pressure based on their ability to plastically deform under certain conditions, as a result of external forces influencing on deformed body (billet). The metals treatment processes divided into two types by appointment: Type for billet production of constant cross-section by length (bars, wires, tapes, sheets) used in building structures or for the subsequent details manufacture. Treatment performs by cutting or by preliminary plastic shaping. The main types of such processes are rolling, pressing and dragging. Type for obtain parts or billets (semi-finished products) having approximately shapes and dimensions the finished details. They require treatment by cutting only to give them final dimensions and the set quality surface. Forging and stamping are the main varieties of such processes. The rolling The rolling consists in billet compressing between the rotating rolls. The billet retracts between the rollers by friction forces, and the pressure forces reduce the transverse billet dimensions. The pressure forces are normal to the rolls surface. The pressing The pressing consists in billet pressing at closed form through the matrix hole. A cross section shapes and dimensions of the billet pressed segment, correspond to the matrix hole shapes and dimensions. The dragging (drawing) The dragging […]
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As we have written it before, there are two methods for determining the grinding balls bulk weight in a mill: Method with complete grinding media discharge from the mill inner drum. Method without unloading grinding balls. In the previous article we considered the 1-st method for determining the bulk weight of grinding media. This article analyzes the second method. The 2-nd method is less labor-intensive, but has a small error, because the sampling is no more than 5% of total volume the grinding media in the mill. Unloaded grinding balls sorted by classes – gradation by diameters. The gradation scale selected in steps of 10 mm. Each class (diameter) is weighing after sorting. Next, determines the average grinding balls diameter in the mill by the weighted average value. The formula for calculating the average grinding balls diameter in the mill ∅ср – the average grinding balls diameter, mm; ∅i – the maximum grinding ball diameter in each class, mm; mi – the grinding ball mass of each class, kg. Then, selected samples placed in a container and re-weighed. Capacity should have no flaws (“waves”, protrusions, holes, etc.) and container form must be of the correct geometric shape (cube or parallelepiped). […]
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In the previous article we considered the method for determining the bulk weigh of new grinding media. Determination the grinding balls bulk weigh directly operating in a ball mill becomes necessary on practice. It is done in order to accurately definition the grinding ball mass during measuring in a ball mill and exclude the mill overloading with grinding balls possibility There are two methods for determining the grinding balls bulk weight in a mill: Method with complete grinding media discharge from the mill inner drum. Method without unloading grinding balls. Calculations by the first method are most accurate, but require a lot of labor costs and time. In this article, we will consider the technique for determining the grinding balls bulk weight in fully unloaded mill. This method used in the mills repair (armor plates replacement). The grinding balls unload from the mill into a special pit (needs to open hatches and pour the grinding balls from the drum during mill scroll). Then, need to definition maximum and minimum grinding balls diameter located in the mill. Unloaded grinding balls sorted by classes – gradation by diameters. The gradation scale selected in steps of 10 mm. Sorting can be done manually […]
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Technological process control of forged steel grinding balls production carried out by the shift supervisor and testing laboratory assistant in accordance with the technological control scheme shown in Table. 1 Table 1. Technological control scheme on ball-rolling complex SHPK 25-120 Technological operation Control location Controlled parameter Inspection method Control periodicity Responsible person for control 1 2 3 4 5 6 Billets acceptance: Conformity check information about incoming billet. Conformity check incoming billet to requirements of normative technical documentation and technological documentation Billets warehouse Melting number (batch number), Steel grade, Chemical composition, Batch weight Visually Constantly Shift supervisor, Laboratory assistant Loading billet into the furnace Billets warehouse, Boot device Nominating Rolgang Steel grade, dimensions, curvature, surface condition of the billet Billet displacement value Visually Visually Constantly Constantly Loading desk operator Melting stream Nominating and furnace Rolgang Different billet brands separation Visually Constantly Billet heating Heating regime Furnace Furnace temperature Metal temperature before rolling Control measuring instruments, VisuallyControl measuring instruments Constantly Periodically Constantly Operator, Laboratory assistant Acceptance of rolling rolls Billets warehouse Roll shop […]
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Metrological assurance the technological production process and quality control of steel grinding balls should comply with Table. 1. Table.1. Metrological assurance the technological production process and quality control of the grinding balls Technological operation Controlled parameter Measurement units Measuring tools Measurement range Accuracy class, graduation value Measuring tool error 1 2 3 4 5 6 7 Loading billet into the furnace Billet diameter Billet length Billet curvature mm mm mm Slide Calipers GOST 166 Measuring roulette GOST 7502 Measuring ruler GOST 427 0-300 0-10000 0-150 2class, 0,1 3 class, 1,0 1,0 ± 0,5 Billet heating at induction furnace Billet temperature at the furnace exit 0С Photo Pyrometer «Quartz-M» 0-1300 ± 1 Acceptance of rolling rolls Caliber dimensions in the calibration section – Cake Size Patterns ± 0,5 Rolling rolls setting Rolling rolls inclination angle 0С Arrowhead with a degree scale 0,5 The rolling: – Rolling temperature regime – Rolling control process Metal temperature before rolling Grinding balls diameter 0С mm Photo Pyrometer «Quartz-M» Slide Calipers GOST 166 0-1300 0-250 2 class, […]
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The quality control the grinding balls hardness and surface checked every hour of the mill’s work, as well as new steel grade rolling in the beginning. Quality control the grinding balls surface, dimensions and hardness carried out by a shift master or laboratory assistant in accordance with the requirements to current regulatory documentation. The grinding balls hardness control carried out in accordance with DSTU 3499-97. Ten grinding balls select from five different batch locations to check the dimensions, quality and surface hardness. If surface hardness control results are unsatisfactory, this indicator checked again on a doubled grinding balls quantity selected from the same batch. If more than two grinding balls don’t meet the requirements during the second test then batch transferred to a lower hardness group. Three balls select from three different locations in each 20-th batch for hardness control of grinding balls the 4th group on 0.5 R depth. If surface hardness control results are unsatisfactory at least for one grinding ball then provide test again on a doubled grinding balls quantity selected from the same batch. If repeated measurements show unsatisfactory results, then needs to perform tests on two consecutive batches until acceptable results. Requirements to normative documentation […]
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Grinding balls produced of steel round billets (according to DSTU 3499-97, DSTU 8538: 2015 or GOST 7524-2015 and TU U 27.1-26524137-1376: 2008). Received billet in the workshop must comply with the requirements to GOST 2590-2006 and regulatory documentation and it should comply to DSTU 3499-97 in terms of the carbon mass fraction and the carbon equivalent value (Table. 1). Table. 1. Ø Hardness group Carbon, % Equivalent, % 15-55 1,2 0,40 0,50 3 0,60 0,70 4,5 0,75 60-70 1,2 0,50 0,70 3,4 0,60 0,75 5 0,80 80-120 1,2 0,50 0,70 3,4 0,60 0,75 5 0,85 The 20mm, 25mm and 120mm grinding balls rolled by billet with a length from 3200 to 4000 mm on a ball rolling mill SHPK 20-120. The 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm and 100 mm grinding balls rolled by billet with a length from 4000 to 6000 mm on the ball rolling mill SHPK 20-120. Limit deviations by billet diameter and length must not exceed the values indicated in Table. 2 Table. 2. Nominal billet diameter, mm Limit deviations of the billet diameter, mm Limit deviations of the billet length, mm Weight 1m of the billet length, kg 30 + 0,3 – 0,7 +50 […]
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In the grinding material process at ball mills becomes necessary to calculate the bulk weigh of used grinding media. The bulk weigh of the grinding balls is necessary to understand the grinding balls mass in the cube, the grinding balls mass loaded into the mill, the prevention of mill overloading with grinding balls, etc. These data often used in operational management of grinding process. Consider a definition technique the bulk weight of new grinding balls. Methodological tables in specialized handbooks indicated the bulk weight of grinding balls different sizes. The indicators were calculated more than 20 years ago. Currently, these data can give an error more than 10%. This is a big error in production operational management. This error is caused by the fact that in the modern grinding balls production apply many materials (different grades of steel, “white” and “gray” cast iron) in contrast to past years. Besides, the actual diameter (size) and shape of grinding media affect the bulk weigh value. Experts of “Energosteel” company have developed a common methodology together with technical specialists of Ukrainian and CIS countries mining & processing enterprises. This methodology allows to accurately determining a bulk weigh of grinding balls. Below, we give […]
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The company “Energosteel” produced an experimental batch (110 tn) the 40mm grinding balls of high carbon steel alloyed by Chromium in January 2017. The batch showed highest hardness values throughout cross section of grinding ball with a surface hardness 65-69HRC and volumetric hardness – 64-66 HRC. Thus, these products comply with the fifth group of hardness (according to both DSTU 3499-97 and DSTU 8538: 2015). Grinding balls have been successfully tested for the impact resistance. 100 balls have been selected from a batch for the experiment. Each selected ball sustained the total impact energy of 64 312 J without destruction. At hardness check of batch grinding balls we have faced with the problem of surface preparation for measurement. Polishing surface by fine-grained stone with coolant even with a minimum machine infeed gave a “tan” on the surface and polishing micro-cracks which distort hardness result of grinding balls to 3-5 HRC measured on a stationary hardness tester. The problem was solved by ultrasonic hardness tester T-UD2 for measuring hardness. Using a suitable method, we achieved increase measurement accuracy, increase productivity control and ensure a high results reliability.
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The main technological process in steel grinding balls production is a hot rolling in helical calibers (see Picture 1) by two rolling rollers (1) deployed on feed angle and rotating in the same direction. Rulers (3) hold billet (2) and grinding balls on the rolling axis. Helical streams (4) are cut into rolling rolls. Helical streams formed by helical flanges (5). The height and width of the helical springs increases during rolling. The round billet is material for grinding balls rolling and has diameter slightly smaller than rolling ball. The rolling performed following way: the flange (5) grip the billet then rotated it and moved it along the rolling rolls gradually compressing the web (6) and formed the grinding ball (7). Grinding ball separates from the billet in end of forming section and protrudes from the calibrated gauge. Picture1. The rolling rollers scheme Streams and flanges hardness of the rolling rolls very important in grinding balls production and affects on products quality, so it must be controlled. Rolling rolls hardness control performed by combined hardness tester T-UD2. For normal rolling rolls operation the streams and flanges hardness should be 50-55HRC – for large diameters and 55-65HRC – for small diameters. […]
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The company “Energosteel” produced an experimental batch the 20mm grinding balls of high carbon alloy steel in the end of December 2016. The batch showed higher hardness values throughout cross section of grinding ball with a surface hardness 61-63HRC and volumetric hardness – 59-61 HRC. According to old national quality standard (DSTU 3499-97) current grinding balls correspond to the 4-th hardness group and according to the new national quality standard (DSTU 8538: 2015) they correspond to the 5-th hardness group. Grinding balls have been successfully tested for the impact resistance. Thirty balls have been selected from a batch for the experiment. Each selected ball sustained the total impact energy of 64 312 J without destruction. This batch of grinding balls was successfully shipped for export.
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We have written about correct definition the hardness group of grinding balls in the article. Here, we would like to pay your attention for nuances in hardness measurement of grinding balls with high volumetric hardness. For conformity grinding ball to the fifth hardness group needs to prepare a flat surface platform by removing metal from grinding ball to R (radius) depth on the one side and to a 0.5 R depth on the other side (Picture 1). Picture 1. Platform preparation for hardness measuring of Ø40mm grinding ball on R depth Hardness measuring all radius parts of grinding ball carried out in accordance with Picture 2. Picture 2. Performance scheme of hardness measurement on a grinding ball platform (depth R) Volumetric Hardness (VH) determined as sum of grinding ball measured values on surface hardness (Тsurf); hardness at 0,25 R (Т0,25); hardness at 0,5R (Т0,5); hardness at 0,75 R (Т0,75) and hardness in the center(Тc). Volumetric hardness (VH) calculated by formula: VH= 0,289 Тsurf+ 0,436 Т0,25 + 0,203Т0,5 + 0,063Т0,75 + 0,009 Тc
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Ukrainian cement industry is the key link of country building complex and completely covers interior demand for cement. 12 large enterprises represent Ukrainian cement industry. It should be noted, just only one plant belongs to Ukrainian equity. Main enterprises of Ukrainian cement industry: Podilsky Cement PJSC Mykolaivсement PJSC Cement LLC (Odessa cement plant) PC “Ivano-Frankivskcement” Dyckerhoff Ukraine PJSC “Volyn – Cement” PJSC “Yugcement” JSC Balcem Pushka Kramatorsk Cement Plant Kryvyi Rih cement plant Amvrosiyivka Cement Plant Dniprodzerzhynsk cement plant In the cement industry used different grinding schemes of raw materials involving milling equipment various sizes. Pipe ball mills used basically. Their ratio of length to diameter is 3:1. Grinding distinguish by: closed cycle grinding (with using sorting machines) or open cycle grinding; the wet or dry grinding process; grinding with simultaneous drying material in the mill. Pipe mills use for clinker grinding in cement production. These mills consist of one camera. The 90mm, 80mm, 70mm, 60mm and 40mm steel grinding balls with third or fourth hardness group (DSTU 3499-97) use as grinding media. The grinding balls assembly depends on size and hardness (mineral composition) of raw material and requirements to the crushed parts size for cement mills. Very often, waste grinding […]
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Today Ukrainian industrial capacity remains at a high level despite the stagnation of its economy. Ukrainian mining, energy and construction industries, where the grinding media used, reduced their production volumes, but still are the flagships of the Ukrainian industry. Ukrainian grinding media producers ensure the company’s needs of these industries. A large part of produced grinding media are grinding balls, but also produce grinding cylpebs. The volume of Ukrainian grinding media market is about 180-200 thousand tons. Requirement partially closed by import equal about 2%. Ukrainian enterprises produce other 98%. Currently, about five Ukrainian grinding media producers can be called active market players. Grinding media production of Ukrainian producers divided into two groups, depending on the material for manufacturing: Production of cast iron grinding media (unalloyed or medium alloyed cast iron balls and cylpebs with low chromium and other alloying elements that provide a hardness). This type of grinding media produced by casting. The range presented on the Ukrainian market includes 60mm, 100mm, 120mm balls and cylpebs. All cast iron grinding media have hardness less than 50HRC. It should be noted, there are no Ukrainian state standards that regulate requirements to cast iron grinding media. That’s why, all manufacturers produce […]
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In Ukraine located about 20% world reserves of iron ore – 80 industrial fields. Domestic mining sector consists of 26 companies. These companies produce the whole range of iron ore resources: an ore, a concentrate, ovoids and agglomerates. Ukraine is the sixth largest iron ore producer. Kryvbas is one of the largest iron ore basin in the world. It includes a series of fields in length over 100 km through Dnipropetrovsk, Kirovohrad and Mykolayiv region. Iron ore with high metal content occur in Kremenchug (Poltava region) and Belozersk (Zaporizhia region) iron ore districts. In the above areas there are six major mining and processing enterprises. They form the majority in Ukrainian production of concentrate, ovoids and agglomerate: Ferrexpo Poltava GOK; Northern Iron Ore Enrichment Works; Central Iron Ore Enrichment Works; Yuzhny Mining and Enrichment Plant; ArcelorMittal Kryvyi Rih; Ingulets Iron Ore Enrichment Works; Ore milling happens in drum mills and steel grinding balls used as milling media. Each of the enterprises has its own specificity in grinding technology, depending on the physical chemical properties of the enriched ores in this enterprise. All enterprises use a classic scheme of raw material grinding and it consists of 3 steps. We consider each […]
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Energosteel Company is Ukrainian manufacturer of forged steel grinding balls. Our products are designed for grinding of raw materials at ore mining and industrial processing facilities, energy generating companies, cement plants. Capacity of Energosteel Company is 60 000 steel grinding balls per year. We are produce grinding balls with a diameter by 20mm to 125mm with high carbon content and the volumetric hardness from 60 to 65 HRC. Despite of the crisis state the Ukrainian economy Energosteel Company has improved indicators of 2015. Compared to 2015 the volume of production and sales of grinding balls increased by 8.6%. It has been achieved thanks to a high performance properties of grinding balls, which highly appreciated by our partners from around the world. Exports increased by 44% and amounted 27% of sales. This became possible thanks to consumption growth in already developed markets of Energosteel Company and through developing new markets, including the MENA and Scandinavian markets. In 2016 marked a significant increase in production (by 22.3%) of grinding balls with the fifth group of hardness in comparison with 2015. In general, the production of grinding balls with the fifth group of hardness and high volumetric hardness was 15.2% of the annual […]
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The operating principle of the ball mill consists of following steps. In a continuously operating ball mill, feed material fed through the central hole one of the caps into the drum and moves therealong, being exposed by grinding media. The material grinding occurs during impact falling grinding balls and abrasion the particles between the balls. Then, discharge of ground material performed through the central hole in the discharge cap or through the grid (mills with center unloading the milled product and mills with unloading the milled product through the grid). In filling mill by grinding balls on 40 – 50% and non-smooth liner, the outer layers slip is virtually absent, but the sliding of the inner layers one on another observed in various modes of operation mill. In a monolayer filling mill by grinding media, they rotate around their axis parallel to the drum axis of rotation. Grinding media are not subjected to a circular motion by a smooth lining, even at high speeds. In a multilayer filling mill by grinding media, depending on the rotational speed, there is possible one of the following modes the grinding media motion: Cascade mode motion – speed mode with a rolling of grinding […]
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Participation of company representatives in the largest specialized exhibition «Mining Turkey Fair 2016». Delegation of of Energosteel company together with official representative on the Turkish market – the company “Process”, attended the 7th International Exhibition «Mining Turkey Fair 2016″ held on the 24-th – 27-th November in Istanbul at the International Exhibition Center «Tüyap Fair Convention and Congress Center». «Mining Turkey Fair 2016″ is the most significant mining exhibition in the area and important marketplace to show, sell and buy the latest mining technologies, equipment and services. This year event hosted 9 472 visitors including 563 foreign visitors from 47 countries. Leading mining companies, suppliers of equipment and materials, investors and key solution providers to build sustainable relationships in Turkish mining industry, attended the fair. As part of «Mining Turkey Fair 2016″, representatives of both companies held business meetings with partners and customers, carried out negotiations with the leading consumers of grinding balls, that allowed to develop a strategy aimed at increasing sales of Energosteel grinding balls in the region.
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