Metallurgist (v.52, #9-10)
Operating a sheet-rolling complex to minimize energy costs by R. L. Shatalov; A. L. Genkin (485-490).
This article analyzes methods that minimize the use of energy resources in sheet-rolling complexes (SRCs). A metal-heating–strip-hot-rolling line is modeled mathematically to develop a method of redistributing energy among the different sections of a furnace–mill SRC. A two-level automated control system that optimizes the rolling regimes is proposed to implement the method for the energy-efficient operation of the furnace–mill SRC.
Keywords: sheet-rolling complex; energy conservation; automation; control
Developing and testing structural steels with superior resistance to cold and to cracking in hydrogen-sulfide-bearing media for use in the production of electric-welded (HFC) oil-field tubing by V. N. Zikeev; V. P. Kharchevnikov; N. V. Filatov; K. V. Anuchin (491-497).
New grades of steel for oil- and gas-line pipe of strength class K55 (steel 07GFB) and for pump-compressor tubing of strength class Ks (steel 18GFB) have been developed and undergone factory testing. The Cherepovets Metallurgical Combine Severstal has tested a new technology for making these experimental steels in a converter and subjecting them to controlled rolling to obtain coiled skelp on a 2000 continuous mill. The Volgorechensk Pipe Plant (owned by the company Gazpromtrubinvest) has used the steels to prepare trial batches of pipes that meet the established requirements.
Keywords: oil- and gas-line pipe and pump-compressor tubing; cold-shortness threshold; resistance to hydrogen-sulfide cracking
Using an AVS radial-forging machine to prepare the ends of tubes for drawing by A. P. Karamyshev; I. I. Nekrasov; V. S. Parshin; V. A. Systerov (498-500).
This article examines the problem of preparing the ends of tubes for drawing. The preparation process entails reducing the diameter of the tube end so that it can be fed freely into the draw plate. One of the main machines used to prepare tube ends is the AVS radial-forging machine. This machine makes it possible to give the ends (grips) a circular or irregular profile. The profile of the tube end that is engaged by the shaping tool is very important in the shaping of tubes of different types and sizes. We therefore obtained and experimentally substantiated a theoretical relation that makes it possible to reliably evaluate the probability of obtaining irregular profiles.
Keywords: radial-forging machine; forging; pressing; irregular and circular profiles for the grip end of tubes
Effective technologies and machines for obtaining cold-worked tubes and other products by V. I. Sokolovskii (501-503).
This article discusses promising methods and machines developed by Ural State Technical University for the cold rolling of tubes made of medium-carbon and corrosion-resistant steels and titanium and zirconium alloys.
Keywords: tube cold-rolling mills with helical-grooved passes; a rotating stand; longitudinal rolling of the tubes; work rolls with a belt drive; hypocycloidal feed and rotation mechanisms; plasticizing coatings
Introduction of flatness gage IP-4 on the continuous Wean-Damiron heat-treatment line at the Samara Metallurgical Plant by S. V. Trusillo; V. A. Agureev; V. Yu. Aryshenskii; A. N. Mironov; V. N. Samonin; A. V. Kuryakin (504-510).
Results are presented from the practical application of opto-electronic flatness gage IP-4 on a continuous heat-treatment line. The gage is being used to increase the flatness of aluminum alloys after their quenching and combination straightening by bending and tension. The gage allows quality adjustment of straightening machines and makes it possible to quantitatively measure flatness in real time. The machine operator can adjust the parameters of the straightening operation and significantly improve the quality of the product. When coils are being straightened, the gage makes it possible to reliably predict the flatness of the rolled product at the outlet of the machine and decide on the need for additional straightening without having to prepare samples of the metal.
Keywords: flatness gage; continuous heat-treatment line; straightening of sheets
Fine microstructure of wire rods manufactured from Sv-08G2S high-plasticity steel by A. M. Nesterenko; A. B. Sychkov; S. Yu. Zhukova; V. I. Sukhomlin (511-516).
This paper presents the results of transmission-electron-microscope and scanning-electron-microscope studies of the fine structure of wire rod made from Sv-08G2S silicon-manganese welding steel, including electron microscope images used to identify the structural components of the wire-rod metal and determine the dislocation density. The wire-rod microstructure was compared against that obtained when a new, optimized process was developed for heat-treatment of the wire rod in a Stelmor line. We show that the wire rod has the highest ductility when the production flow includes long-term holding of the wire-rod coils under quasi-isothermal conditions (under insulated hoods with a cooling rate 0.2–0.3°C/sec) in such a way as to minimize the number of bainite-martensite areas when the structureless martensite (hardenite) content does not exceed 5%. The resulting process and optimized microstructure enabled us to achieve a relative deformation of 98% when direct-drawing wire rod from Sv-08G2S alloy steel.
Keywords: welding rod; steel microstructure; heat-treatment modes; highly drawable metal
Modern rolls for the 2000 mills at the Cherepovets and Magnitogorsk metallurgical combines by K. Gostev (517-523).
Highly-productive bimetallic cast backup rolls of grade AST70X have been proposed for use on continuous wide-strip hot-rolling mills. Use of these rolls presents new possibilities for improving the quality of the rolled products and mastering the production of new types of products while simultaneously lowering production costs.
Keywords: hot-rolling mills; backup and work rolls; improvement in the quality of rolled products; reduction in production costs.
Damping capacity of the roller-type hinges of spindles in the drive rolls of rolling mills by V. I. Bobukh; G. S. Sukov; I. A. Bobukh; A. V. Satonin (524-529).
The damping capacity of universal roller spindles is determined for roll guides operating under different types of conditions.
Keywords: roller-type hinge; damping capacity; rolling-mill drives; corrected stiffness
Improving the tribological characteristics of powder steel parts via multicomponent diffusion saturation of working surfaces by A. B. Korostelev; D. A. Chumak-Zhun (530-532).
This paper discusses a new method for chemical heat treatment – multicomponent diffusion saturation of the surface of powder-steel products with chromium, silicon, and manganese in order to improve product performance, especially with respect to tribological properties. The samples to be saturated were fabricated from powdered iron, and powdered 40, 60, and 40N2M steel. The control samples consisted of hot-stamped and improved 40p steel and U8 compact steel heat treated to hardness 58–62 HRCe. Chromium-, silicon-, and manganese-saturated samples and samples not saturated with these elements were tested to determine their tribological properties. The tests were performed using a tribometer. The results obtained suggest that this three-component (chromium, silicon, and manganese) diffusion saturation technique is promising and of current importance for production of materials meeting certain specifications.
Keywords: powder steel; surface; multicomponent diffusion saturation; wear resistance; wear; coefficient of friction; friction path; wear spot; strength
Blast furnace no. 6 at the Novolipetsk Metallurgical Combine – the best Russian design by I. F. Kurunov; S. S. Lyapin; V. L. Emel’yanov; V. N. Titov; D. D. Ivanov (535-543).
This article examines the successes and difficulties encountered in the operation of blast furnace No. 6 at the Novolipetsk Metallurgical Combine over its 30-year history.
Keywords: blast furnace; blow-in; furnace operation; main technological parameters
Use of mathematical models to optimize process parameters in the sintering of Mikhailovskii and Lebedinskii concentrates by A. A. Panychev; A. P. Nikonova (544-551).
Formulas are presented to describe the mathematical relationships between the parameters that govern the sintering of iron-ore concentrates on belt-type sintering machines. Use of the formulas makes it possible to optimize the process and automate it through computer programming. Experimental data are used to solve the equations and construct mathematical models for the agglomeration of a charge composed primarily of a mixture of Mikhailovskii and Lebedinskii concentrates. The models are of practical value for sintering such mixtures and can be used to construct similar models for the sintering of charges of other compositions.
Keywords: charge agglomeration; automation of the sintering process; mathematical models
Monitoring and selection of optimum production parameters for metallurgical-grade lime to be used in ferrous metallurgy by V. O. Golubev; V. E. Nikol’skii; B. S. Abezgauz; Ya. E. Shklyarskii; E. A. Zagrivnyi; I. N. Beloglazov (552-560).
We describe the specifications for production of ISO and EN-compliant metallurgical-grade lime; present analysis results and requirements regarding the chemical composition of lime; present the results of tests to determine the reactivity of lime; and propose an explanation for the essential kinetics of the dissociation process in lump lime.
Keywords: chemical and particle-size composition; kinetics of lime burning; burdening and homogenization of lime; production of calcium lime; shaft furnaces and rotary furnaces; degree of burning; reactivity of lime; metallurgical grade lime; lime standards
Effect of plasma treatment parameters on the structure and properties of type 60G steel by M. V. Il’ichev; A. S. Tyuftyaev; O. V. Livanova; G. A. Filippov (561-566).
Successful use of plasma hardening technology requires a search for optimum plasma treatment methods, especially when there is a change in the chemical composition of the metal in the products. In order to study the impact of the chemical composition of steel on the structure and properties after plasma hardening, various steel alloying options were selected with respect to concentration of major elements affecting phase transitions upon cooling. In wheel steel, these elements are carbon, manganese, chromium, and others. This paper describes the results of metallographic studies and mechanical tests.
Keywords: steel; plasma treatment; study
Procedure for determining the stress state of a work roll by the boundary-elements method by V. I. Kadoshnikov; V. M. Moskvin; E. L. Belevskaya (567-573).
This article examines a loading scheme for a sheet-mill work roll that places the roll in a plane stress state. This state is completely determined by the stresses in a ring that represents the intersection of the roll’s cross section by a plane which is perpendicular to its axis. As part of preparing data for calculation, the circumferences of the ring are divided into individual elements and the normal and shear stresses acting on these elements are calculated. Formulas are proposed for dividing the arcs that comprise the outer circumference of the ring into discrete sections and determining the average normal and shear stresses for rectilinear boundary elements. Replacing the inner and outer circumferences of the ring by polygons does not violate the conditions required for static equilibrium. An example is given to illustrate preparation of the data and its use in calculations.
Keywords: stress state; subdivision of an arc; rectilinear boundary elements
Ensuring product quality in hardware-manufacturing technologies by A. G. Korchunov (574-581).
This article attempts to solve problems related to ensuring product quality in hardware manufacturing operations by using principles from the theory of technological inheritance. Measures are proposed to eliminate undesirable technological inheritance that lowers product quality and examples are given to illustrate their practical use in hardware production.
Keywords: hardware production; quality indices; processing regimes; theory of technological inheritance
Evaluating the maximum draft and safety factor in wire-drawing by G. N. Gur’yanov (582-587).
An equation describing the exponential dependence of the yield point of metal that is to be drawn on the draft in the drawing operation is used to calculate the safety factor and the limiting and maximum drafts. The calculations are performed on the basis of simple formulas that are similar in form and are normally used to determine the axial drawing stress in the working cone of the draw plate. An increase in the strain-hardening coefficient and external friction is accompanied by an increase in the difference between the values of the safety factor and limiting and maximum drafts calculated by using different formulas for the axial drawing stress.
Keywords: drawing; safety factor; angle of the working cone of the draw plate; friction coefficient; strain-hardening coefficient
Cables with a steel core for hot-metal charging cranes by V. G. Popov; D. F. Gabtykaev (588-591).
Cables with a steel core 42 mm in diameter are used on hot-metal charging cranes. Heat is released as molten pig iron is poured into the converter, and the resulting superheated gases and flames (whose temperature sometimes reach 1300°C) act on the surrounding production equipment, building structures, and cables. An analysis of defects in the steel cables of such cranes has shown an increase in the incidence of rejection of these cables for technological and design-related reasons. The main reasons for the failure of cables in inspections are loss of cross section, extrusion of the strands, and curvature. The use of cables with a spring-type core makes it possible to lengthen their service life and make the formation of the defects just mentioned less likely. Cables of this type are more flexible, which improves their performance on blocks and drums. The spring-type core ensures that the cable will remain intact during service and that the lubricant will be evenly distributed among the strands.
Keywords: hot-metal charging cranes; cable rejection; spring-type core