Continuous Rolling Mill Research Articles

Study of Deformation's Indexes of Rolls of Different Designs

The elastic deformation of rolls influences the final thickness, thickness variations of strip and distribution of contact stresses. Prospective direction to address the problem of ArcelorMittal Temirtau JSC is the use of new roll materials. Calculating of elastic deformation of four-roll unit of continuous wide-strip hot rolling mill 1700 at ArcelorMittal Temirtau JSC for the actual profile of rolls of the "old", "modern" and "up-to-date" designs. Calculations have showed that during the use of rolls of "up-to-date" design AS1180HH in stands 6-8 bend deflection is reduced by 35-36.8%, and the design of rolls HVS80 in stands 9-12 by 54.5-56.1% that will allow the minimization of strip defect non-flatness at rolling of both narrow and wide strips.

Genetic Algorithm Rolling Mill Layout Optimization

Štore Steel Ltd. is a small flexible steel plant in Slovenia. In 2010, the new continuous rolling mill, which has a technical capacity of 250,000 tons per year, was installed. The new continuous rolling mill, which entailed a corresponding reduction in space, required an urgent relocation of machinery. The genetic algorithm was used for the optimal rearranging of the machinery. Two-dimensional or three-dimensional representation of the machines without any kind of geometrical restrictions can be used in the proposed genetic algorithm. The layout efficiency after machinery relocation could be increased by 58.1%, but due to spatial, financial, and practical constraints, the layout efficiency is only 13.58% higher.

Celebrating ASM’s First 100 Years in Supporting Materials Innovation: 1913-1923

Abstract In recognition of ASM International's 100-year anniversary, AM&P highlights historic events and technological advancements that occurred over the course of those years. This issue covers the first decade, from 1913 to 1933, which includes the awarding of a patent for the nitriding process, the invention of the Rockwell hardness tester, the commissioning of "Big Bertha" in WWI, the inaugural edition of the ASM Handbook, and the start-up of America's first continuous hot rolling mill in Ashland, Ky.

An investigative study on the performance of twist roll machine in a continuous cold strip rolling mill

In many modern continuous production lines of steel sheets, a twist roll machine is used to change the strip direction for shortening the production line. A twist roll machine typically consists of a cylindrical body on which some guide rollers are mounted in rows to gradually change the traveling direction of the strip when passes over the guide rollers. In this article, quality of the sheets after exiting an industrial twist roll machine is first investigated. The amount and distribution of wear on the guide rollers are also assessed by measuring and comparing diameter at different sections of selected worn and new guide rollers. The specific wear rate as well as friction coefficient for guide rollers made of two different popular polymers is measured by pin-on-disk wear tests. Details of the strip path on the twist roll machine as well as contact between the strip and all the guide rollers are specified, and stress distribution in strip and the guide rollers is studied by finite element analysis. Effects of the guide rollers material and arrangement, the bridle rolls tension, and width and thickness of the strip on the amount and distribution of wear on the guide rollers as well as the elasto-plastic response of the strip are studied. The results are utilized to propose techniques for reducing defects on the sheet and the guide rollers, and finite element simulations show the effectiveness of these techniques.

Influence of Non-Uniform Temperature Distribution on Metallic Charge Length on Energy and Force Parameters During Groove-Rolling

Change in the temperature of band over its length, associated with the stock being non-uniformly heated in the furnace, influences the variations in the magnitudes of energy-force parameters. Using the FEM (Finite Element Model) programs for the computation of the values of the energy-force parameters can take into account the distribution of temperature over the band length. The mathematical model of the computer program Forge2008 was used to theoretically examine the energy-force parameters and plastic metal flow in the roughing stands of the continuous rolling mill. The results of experimental investigation of influence of the non-uniform temperature distribution were presented on the metallic charge length on the energy and force parameters and dimensions of the band during round bars rolling. Thermovision monitoring energy and force parameters monitoring were carried out in continuous rolling mill D350 in one of the Polish industrial plants. On the basis of obtained results, it could be stated that non-uniform distribution of temperatures along the charge length causes local increase of energy and force parameters values and also such distribution affects the local increase of the width of rolled band. The rolling process of charge with nonuniform distribution of temperature could lead to exceeding required dimensional tolerances of the final products.

Study on Cooling Process of Hot Rolled Wire Rod with Dual Phase Microstructure

In the present paper effect of post deformation cooling rates on microstructure of ER70S-6 steel was investigated by using Gleeble1500 simulator. From the results, a controlling cooling process for obtaining dual phase (DP) microstructure was designed to produce hot rolled wire rod with a diameter of 6.5mm in a continuous no-twist and high-speed wire rolling mill, and the microstructures and the tensile properties of the wire rod were analyzed. The results showed that ER70S-6 steel deformed at 845°C and cooled at a rate of faster than 10°C/s had a DP microstructure with grain size of less than 8.3μm and martensitic volume fraction of 9-11%. The hot rolled wire rod cooled by blowing air had a DP microstructure with a grain size of 8.2μm and martensitic volume fraction of 11.5%. The present wire rod was superior to that of the same steel with ferrite plus pearlite microstructure in tensile properties, with yield strength level of 335-345MPa, ultimate tensile strength level of 600-620MPa, plastic elongation of 26.5-31.5% and strain hardening exponent of 0.221, respectively. ER70S-6 steel wire rod with DP microstructure showed promise of meeting the requirements for grade 8.8 fastener.,In the present paper steel wire rod with DP microstructure showed promise of meeting the requirements for grade 8.8 fastener.

Study on the Dynamics Performance of the Drive Train of Flying Shear Machine

Flying shear machine is widely used in continuous rolling mill production line, and its performance is largely depended on the transmission system. Here a model is established with multiple backlashes, time-varying mesh stiffness and error excitation to investigate the dynamics performance of the transmission system during the process. Also, effects of parameters are discussed. It’s believed that it will be helpful for the design of the flying shear machine

Eliminating surface defects in rolled sheet due to vibration of the working cells

Surface defects of cold-rolled sheet in the form of transverse ribbing and cold-hardening bands are due to vibration in the working cells of the continuous rolling mill. The vibration is excited by impact of the working-roller supports on the frame’s supporting plane during reverse motion within the available gap. Means of eliminating these defects are developed on the basis of new approaches to cold-rolling theory.

Machinery-electric-hydraulic Coupling Vibration Control of Hot Continuous Rolling Mills

Thin slab continuous-casting and continuous-rolling mill appear different degree of serious vibration phenomenon when rolling thin strip in the world.The vibration phenomenon lead the strip and rolls to generate obvious stripe,which affects product quality and enterprise external image and economic benefits.Using self-made comprehensive telemetry system test the rolling mills vibration parameters,force and energy parameters,electric parameters and technological parameters in the site.Analysing the test signal in the time and frequency domain,characteristics and rules of vibration can be obtain.Through the theoretical and simulation research,it is found that rolling mill do exist vertical-twist coupling vibration,electro-mechanical coupling vibration and liquid-mechanical coupling vibration phenomenon.So confirming the nature of the rolling mill vibration is mechanical-electrical-liquid coupling vibration.Based on modification and optimization of the electric drive control system and AGC system,applying the designing second order torsional vibration observer in the main drive control system and optimizing AGC parameters,the main drive system of the second order torsional vibration is restrained effectively.By site assessment,the roll system vibration is reduced obviously,and it is inhibited rolling mill mechanical-electronic-liquid coupling vibration phenomenon,so it has obtained the remarkable economic and social benefits.

The Effect of the Normalizing Rolling of S355J2G3 Steel Round Bars on the Selected Mechanical Properties of Finished Product

The paper presents investigation results related to the effect of application of round plain bar normalizing rolling on the selected mechanical properties of finished product. The research was carried out for the process of rolling 38 mm-diameter plain round bars made of constructional steel S355J2G3, based on actual specifications used in industrial conditions in a continuous bar rolling mill. In the course of investigation the yield stress, YS, and the tensile strength, TS, were determined. With the aim of evaluating the effect of controlled (normalizing) rolling on the mechanical properties of the considered steel grade, Zwick Z/100 testing machine was employed and analytical relationships were used. On the basis of performed research work it was established that enhancement of mechanical properties of the considered steel can be obtained as a result of application of the normalizing rolling process.

The Influence of Rolling Temperature on the Energy and Force Parameters during Normalizing Rolling of Plain Round Bars

The paper presents results of theoretical and experimental studies on the influence of strip temperature reduction at the final stage of the normalizing rolling process in a continuous bar rolling mill on the energy and force parameters. The studies were carried out for 38 mm-diameter round bars of constructional steel S355J2G3 (St52-3 acc. to DIN). At the first stage, numerical modelling of the rolling process was performed for the conditions of the currently used rolling technology. The aim of this stage of the work was to determine the distribution of strip temperature during the rolling process and of strip temperature after the rolling process. The obtained computation results were compared with the measurement results recorded during the actual rolling process using a thermovision camera. A computer program designed for three-dimensional modelling of metal flow during rolling in passes was used for the determination of the distribution of strip temperature during rolling. The second stage of the studies included modelling of the bar rolling technology modified by applying normalizing rolling after introducing accelerated strip cooling at the final stage of rolling. The aim of this stage of the work was to establish the influence of reduced strip temperature on the change in the values of the energy and force parameters of the process. By comparing the computed values of rolling power with those of the permissible power it was found that these values were lower than the permissible power of the rolling machine’s main drives installed in the Rolling Mill under analysis. Thus, it was demonstrated that it was possible to implement the process of normalizing rolling in the conditions of the Shape Mill under study.

Continuous profiling of welded pipe in an automatic line

9 In the theory of weldedpipe production in auto� mated lines, calculation of the energy parameters is of great importance. The tractional and vertical forces within the con� tinuous rolling mill are fundamental to the design of the working tool, to selection of the mill configura� tion, to determination of the possibility of manufac� turing the required pipe range using specific equip� ment, and to the development of technological pro� cesses. The stability of the process is ensured by the specified distribution of forces, which, in turn, affects the formation of satisfactory welded profile in the mill. Various methods exist for determining the energy parameters of the equipment in formulating the geo� metric dimensions of the initial blank. These methods have particular advantages and disadvantages. For example, a method for calculating the param� eters of the roller strand, the forces, and the deforma� tion of the blank was proposed in (1). However, this method ignores the contact area of the tool and the blank and hence cannot determine the relation between the energy parameters of the process and the tool dimensions (the roller diameters at the bottom and at the flange). The total tractional forces required to move the blank, the length of the shaping segment, and the groove width may be calculated by the method in (2). However, the contact areas are again ignored. The cal� culated shaping forces are unrelated to the deformed state of the blank in the mill. A procedure for determining the energy parameters in strip shaping was outlined in (3). However, the deformation arising in profiling at the junction of the sides in the blank was ignored. The retarding axial force in the creep zone was also disregarded. In the present work, we propose a method for cal� culating the energy parameters in profiling round welded blank in fourroller grooves of a pipe mill, with uniform decrease in curvature of the sides over the external surface and decrease in the reduction over the cells (4).

Open versus closed innovation: development of the wide strip mill for steel in the United States during the 1920s

A paired comparison is made between rival attempts to develop the first continuous rolling mill for wide strip in the USA during the 1920?s. One firm was secretive, the other relied upon collaboration. Development of the wide strip mill is a natural experiment comparing closed and open innovation since two firms were competing for the same target using different institutional arrangements for their R&D. Wide strip rolling technology was developed by rival teams in the USA during the mid-1920?s. The less successful team at Armco, Ashland, Kentucky was closed to outside influences. Breakthroughs came from Columbia Steel at Butler, Pennsylvania which pursued an open pattern of cooperation with equipment suppliers. Columbia Steel?s collaboration with machinery suppliers, use of independent advice on bearing technology and willingness to learn from precursors in copper rolling enabled them to build a successful wide strip mill complex, commissioned in 1926. Butler established the dominant design for the next 80 years. The leading equipment supplier at Butler, the United Engineering and Foundry Co., led global sales of the technology for four decades. It is not clear how far this example of successful open innovation in the US inter-war economy is typical. Historical studies of the management of R&D focus on formal, science based research in large corporate labs rather than engineering development.

Analysis of rolling force model in cold rolling mill

A rolling force model of continuous cold rolling mill based on elastic and plastic mechanics was developed and successfully applied in the control system of a 1420 mm cold rolling mill in Baosteel. Considering simplicity and practicability of calculation, stress of elastic zone and plastic zone during the cold rolling process was calculated and analyzed by incorporated simple finite element method and recursive calculating method. Compared with the measured rolling force, the results of the rolling force model are beyond 96.5%. A method for optimizing rolling force by improving reduction, dimension, coefficient of friction, deformation and tension is put forward.

Simulation of the state of stress in a strip in a deformation zone with two neutral sections during cold rolling

It is found that a deformation zone with two neutral sections can exist in a strip during cold rolling in certain working stands in continuous rolling mills. A second neutral section appears in the region of elastic recovery of part of the strip thickness at the end of the rolls. A reliable procedure has been developed to identify the type of deformation zone; it can determine the number of neutral sections in the deformation zone of each working stand in a rolling mill. A method for the calculation of the contact stresses, forward-creep coefficient, and rolling force in the deformation zone with two neutral sections is described. The application of this method decreases the error of force calculation for rolling mills.

Assessment of Best Scheduling Practice in Continuous Casting and Hot Rolling of Stainless Steel Strip by System Dynamics Simulation

A rapid flow of materials with little intermediate buffering between steel mill and hot strip mill has many benefits. One is energy savings due to raised charging temperature in the reheat furnaces of the hot strip mill. Another is that tied capital is freed up, thereby improving mill economy. Still, it is not unusual that average lead-time is in the order of days, or even weeks. The aim of the present work was to show how lead-times from casting to rolling could be improved by changes in the scheduling function. A System Dynamics model of a stainless steel strip production facility with continuous caster and hot rolling mill was created. The model was used to study the dynamics of the system in response to changes in parameters that defined the scheduling configuration. More frequent schedule updating generally resulted in less work in process (WIP) and shorter lead times from casting to rolling, with resulting higher charging temperatures. The amount of oscillation in the system was also reduced. More frequent work roll changes were required when scheduling frequency increased, resulting in an increased fraction of setup time in relation to total processing time. Therefore, a development towards increased scheduling frequency may have to be complemented by efforts to reduce changeover times. The conclusion was that dynamic scheduling routines with frequent schedule updating result in better overall performance of the system due to lower WIP and better heat utilization. Dynamic scheduling routines with frequent updates make the system respond better to changes in the system and give better overall performance. The result is lower WIP, increased energy efficiency and less oscillation in the system.

Автоматизация действующих непрерывных прокатных станов на основе компьютерных технологий

Автоматизация действующих непрерывных прокатных станов на основе компьютерных технологий

A Framework for Design of Intelligent Simulation Environment

This study describes a framework for design and development of intelligent simulation environment. The intelligent simulation environment prescribes an integrated rule-based approach to simulate and optimize a manufacturing system. An intelligent simulation model is a computer program capable of improving its performance by referring to production constraints, system's limitations and desired targets. It is a goal oriented, flexible and integrated approach and produces the optimum solution by referring to an integrated database. The properties and modules of the prescribed intelligent simulation environment are: 1) parametric modeling, 2) flexibility module, 3) integrated modeling, 4) rule-based module, 5) integrated database and 6) learning module. The design phase of the intelligent simulation environment is discussed for a large multi product assembly shop and a heavy continuous rolling mill system.

Optimization of a Heavy Continuous Rolling Mill System Via Simulation

Optimization of a Heavy Continuous Rolling Mill System Via Simulation

The theoretical and experimental analysis of the effect of asymmetrical rolling on the value of unit pressure

An analysis of asymmetrical band rolling in the last two stands of a finishing sheet hot rolling mill has been performed in the study. Investigations were carried out to determine the range of values of roll peripheral speed asymmetry ratios which would assure the permissible bending of band upon its exit from the roll gap and to reduce the value of the overall metal pressure on the rolls without causing overloading of the drives of the finishing group of the continuous sheet rolling mill. The application of asymmetrical rolling on the last two stands has made it possible to reduce deviations in band thickness, decrease the minimum thickness of finished sheet from 2.00 to 1.80 mm and increase the width of sheets produced in the thickness range from 1.80–2.00 to above 925 mm. The use of asymmetrical rolling can be compared with the use of tension and back tension with resulting reduction of the force of the overall metal pressure on the rolls. A lower value of the pressure force means a smaller elastic deflection of working stand elements and a possibility of using smaller values of working roll bending forces. There are no concrete guidelines in the literature concerning the choice of the values of roll peripheral speed asymmetry ratio for real sheet rolling mills, at which a reduction of the forces of the overall metal pressure on the rolls and either a straight band or the one with a small curvature enabling the accomplishment of the rolling process in successive rolling stands and band coiling will be obtained.