Determination of destruction cause of experimental mill roll of stand roughing group of mill 150.

High quality of purchased resources plays a critical role under the conditions of severe international competition. Raw materials, materials and components are purchase for product production and their quality is an essential part in the production of steel at OJSC “BSW – Management Company of the Holding “BMC” holding». The problem of excessively high level of dynamic loads is especially acute for roughing stands. The main reasons for dynamic overloads are intense transient processes occurring in the rolling cycle, the presence of elastic constraints and gaps in the system, imperfection of electric drive system and errors made during development. Therefore, there is a need for selection of material and manufacturing technology for mill rolls capable to withstand such loads for a sufficiently long period. Investigations of destruction causes of experimental mill roll of stand roughing group of mill 150 of section rolling shop at OJSC “BSW – Management Company of the Holding “BMC” holding were carried out. Main classification features are established based on the analysis of the fracture. The results of metallographic studies of microstructure and chemical composition of central and subsurface zone roll fragments are presented. The reason of destruction of experimental mill roll was discovered – nonconformance of roll material grade with the requirements of technological instructions and normative documentation for rough group of stands No. 1–3

Modeling and Research of the Deformation Treatment Process of 585 Gold Fineness Alloys for Obtaining Wire for Jewelry Purpose

The results of studies of the process of obtaining wire for the manufacture of jewelry chains from new nickel-free 585 gold fineness alloys are presented.New 585 gold fineness alloys, alloyed with palladium, silver and other elements, and as modifiers - with rhodium and ruthenium in the stated quantities have been proposed.By modeling the process of section rolling of rods in octagonal calibers using the variation method of minimum total power, the broadening of the metal and the energy-power parameters of rolling rods from the investigated alloys have been determined. The regularities of their change have been found. Software has been developed for designing processes for the production of longish deformed semi-finished products and technological modes of rolling and drawing of new gold alloys.With the help of experimental studies, the adequacy of the results of calculations and modeling was checked and new data were obtained on the mechanical properties of the metal and its structure.It has been found that the proposed alloys and the modes of their processing using the processes of section rolling and drawing make it possible in industrial conditions to obtain jewelry wire with a diameter of up to 0.25 mm with the level of mechanical and operational properties required for chain tying.

Estimation of the resource of sliding bearings of roll reinforcement in section rolling mills

A new bearing unit is developed for the input roll reinforcement of the stands of 170 ПАО MMK section mill. A model of wear of sliding bearings is considered, which establishes the influence of the design parameters of the bearing, the frictional characteristics of materials and the conditions of surface treatment on the resource, friction force and contour pressure. Keywords: section rolling mill, hot rolling, roll reinforcement, sliding bearings, wear model, resource. [email protected]

Mechanics of the H-Beam Rolling in the Universal Beam Groove

The formulation and solution of the problem of double-T section rolling in universal groove using the variational principle of minimum total power with aim to determine integral forming and energy-power parameters are presented. Geometrical model of the deformation zone and the kinematically admissible velocity field were constructed accurate within two unknowns: forward slip coefficient ν, flange spread (pulling-down) . The comparison of the calculated values with the experimental data obtained on a laboratory mill 200 confirmed that the variational principle of minimum total power has sufficient accuracy for analysis of double-T section rolling in universal groove. The mean statistical error of torque calculation is 12.3 % while load calculation is 18.7 %.

Determination of Contact Pressure during Double-T Section Rolling in Universal Beam Groove

Based on application the physical constraint equations of state of stress and strain of the metal for the isotropic medium, we get expressions for components of stress tensor. The new theoretical method for calculation of contact pressures and rolling force during rolling of double-T section in a universal beam groove was developed. Reliability of the method is confirmed by the results of experimental verification for conditions of rolling of H-beam No 35B1, 40K2 and 45B2 from steel 15CrSiNiCu on the universal beam mill of "NTMK". The average calculation error is 6.4%. The new method is recommended for calculation pass design and technological modes of H-beam rolling on rail-beam and section mills, equipped with universal stands.

Optimization of Technologies of Section Rolling By the Conditions of Saving Energy Resources using the Expert System

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Study Structure and Properties of Reinforcing Rolled Coils by V-Alloyed C – Mn – Si - Steel with Dual- and Multi-Phase Microstructures

Thermo-mechanical controlled rolling (TMCR) schedules have been studied on the wire line of 400/200 section rolling mill to manufacture 6.0 – mm - diameter reinforcing wire in coils by V-alloyed C – Mn – Si - steel that has dual-phase (DP - ferrite-martensite (bainite)) and multi-phase (MP - ferrite-martensite (bainite) - pearlite) microstructures.It has been established that high tensile strength and plasticity values were achieved in this 6.0 – mm wire in coils (YS0.2= 530-550 MPa; TS= 785 – 885 MPa; El5 = 15.0 – 29.0 %) which were in full compliance with national standard specifications such as ASТM A 615 (USA), JIS G 3112 (Japan) and KSD 3504 (the Republic of Korea)), when the TMCR schedules involving laying head temperatures ТLH from 1024 ºС to 1063 ºС were employed ensuring formation of MP microstructure.

Analysis of Efficiency of Roll Pass Design Options for Roughing Stands of Section Rolling Mill

The analysis of two roll pass design options of ten roughing stands atOJSC “MMK” 370 rolling mill has been performed. The usage of a new form of the roll grooves will allow achieving higher durability of the rolls. Lesser rolls consumption will allow saving up to 800K rubles annually. More uniform load distribution by the stands will reduce the possibility of main mill lines equipment breakdowns due to the jumps of rolling torque in the most loaded non-equiaxial stands. Better contact conditions and higher billet stability at the input into equiaxial grooves will reduce the amount of metal clogging. Moreover, a changed strain diagram – with higher roll pass design efficiency factor – will increase the roll out of foundry production defects.

Simulation of Thermal Conditions during Rolling of I-Beams at Modern Rail and Structural Steel Mill

Based on the application of variational principle of minimum total power and statistical generalization production experience procedure for the calculation of roll pass design and process-dependent parameters of double-T section rolling on universal rail-beam mill was developed.With the procedure developed, a computer simulation of rolling of the I-beam 35B2 was performed. It has been shown that the proposed procedure for calculating the calibrations rolls for the I-beam rolling in universal calibers ensures that the effective strain of the profile elements is distributed evenly.The study was made within the project, part of state job in the field of scientific activity No 11.1369.2014/K dated 18.07.2014 (State registration number: 114122470051).