A. Kawałek

Theoretical analysis of the asymmetric rolling of sheets on leader and finishing stands

Abstract A theoretical analysis of the asymmetric rolling in The Plates Hot Rolling Mill of Tadeusz Sendzimir Steel Work in Cracow has been performed with finite element software Elroll with an assumed rigid–plastic model of the deformed metal. The theoretical analysis of the asymmetric rolling process, which was performed based on Elroll computer software, required the definition of the mechanical properties of the materials examined. Before making the selection of steel grades for analysis, data deriving from the system of controlling the finishing stand group at the Sendzimir Steel Works of Cracow were reviewed and steel grades defined in the system were analysed, the latter being grouped into sets, each with an assigned code of mechanical properties. Each of these groups is characterised by different coefficients of a general equation that defines the dependence of yield stress on temperature, strain rate, total rolling reduction, and the rolling stand number. On the base of the obtained results of the computer simulation the technology of the asymmetric rolling of plates in a continuous rolling mill has been elaborated. Within this framework results of the computer simulation are presented.

Application of Torsion Test for Determination of Rheological Properties of 5019 Aluminium Alloy

The paper presents the results of the study aimed at determination of plasticity of hard-deformed aluminium alloy grade 5019 in terms of parameters characteristic for the process of extrusion. The examinations were carried out in hot torsion test. Using the developed mathematical model of the analyzed alloy the mathematical modelling of torsion test was also performed.

Plastometric Testing of Rheological Properties of 5083 and 5754 Aluminium Alloy

The paper present a method for determining the real steel work-hardening curves based on the cylindrical specimen compression test. The subject of testing were 5083 and 5754 aluminium alloy. The tests were carried out using the physical simulator of metallurgical processes GLEEBLE 3800 (Figure 1a) for the temperature range of 400 ÷ 560 °C and the strain rate range of 0,1 - 1,0s-1. Based on plastic deformation parameters recorded during the experiment, mathematical processing, that is the digital filtration and approximation of the obtained testing results, will be performed. Then, using the inverse method, the actual values of the coefficients of the numerical models for the rheological properties of the tested materials will be determined.

Physical Simulations of the Controlled Rolling Process of Experimental Steels with Modified Chemical Composition Allocated to Pipelines

The research presented in the paper was carried out for the experimental steels with modified chemical composition allocated to pipelines for 760÷1180 °C range, strain rate s–1 s–1 and different distributions of particular reductions between passes were presented. Physical modeling of the rolling process was carried out upon using the GLEEBLE 3800 simulator. The research was based on the findings of the paper [1].

Plastometric Modelling of the E635M Zirconium Alloy Multistage Forging Process

The purpose of the process was to develop the guidelines for the new technological process of producing E635M zirconium alloy bars, including the conditions and schemes of deformations in individual open-die forging operations on a hydraulic press. The determined range of hot plastic deformation parameters (temperature, strain, strain rate) will contribute to the intensification of the plastic flow process in individual technological forging operations at a lower total energy consumption, with simultaneous homogenization of the structure in finished bars. Plastometric modeling of the process of hot forging square cross-section forging for industrial conditions and according to a newly developed scheme was carried out within the study. The examination was performed using the Pocket Jaw module of the plastometric device Gleeble 3800.

The Physical and Numerical Modelling of Heat Treatment of Experimental Steels for Pipelines

The paper presents the results of the physical and numerical modelling of heat treatment of experimental steels for pipelines. Simulation has been conducted at the Institute of Metal Forming and Safety Engineering of Częstochowa University of Technology. The numerical modelling of heat treatment has been carried using commercial program TTSteel. Based on the results of computer simulation, changes in steel microstructure during continuous cooling have been analysed, and the characteristics of temperature and the diagram of Continuous Cooling Transformation (CCT) have been constructed. Numerical research has been verified running the physical simulation of heat treatment of steel using dilatometer DIL805 A/D. The characteristic temperature of steel and the size of the former austenite grains have been determined. Also, the metallographic examination of the samples was conducted and Vickers hardness was tested. The obtained results have been used for building a real CCT diagram of steel.

Numerical Simulation of the Rolling Process of Pipeline Sheet

The Institute of Metal Forming and Safety Engineering has developed technology for manufacturing grade X80 pipeline plates according to European standard EN 10208-2. Experimental chemical compositions ensuring a high level of yield strength have been developed. The article describes a method for selecting chemical composition [1]. The advancement of rolling technology takes much time and many calculations. Thus, using numerical simulations provides a possibility of a theoretical analysis of the plates made from new materials [4], [5]. Preliminary studies [1] have disclosed a large volume of deformations during the rolling process, which causes the distortion of rolls and generates heavy loads. For the theoretical analysis of rolling plates, Forge 2008® was used. The paper presents the obtained results of energy analysis and strength parameters displayed in Figure 1. The article considers a total amount of pressure on metal rollers and changes in the rolling moment.

The Study of Heat Transfer Coefficient during Cooling Plates of High Strength

Nowadays methods of hot-rolled sheets should ensure high mechanical and plastic properties of sheets, in-line rolling. Such technologies require application of devices for accelerated cooling of a band after last deformation. The essential thing in this process is selection of an appropriate positioning of the cooling intensity. The paper presents results of the cooling intensity for the selected air-water nozzle. On the basis of the results, the map of distribution of heat transfer coefficient for the nozzle to the surface of the cooling was performed. These tests were carried out for different settings of water and air. The research was carried out for high-strength steel. The obtained results allow executing of computer simulation of the impact of cooling intensity on the final product’s structure.

Application of asymmetry in plate rolling on the finishing stand of a rolling mill 3600

Abstract This publication presents results of numerical simulation of the asymmetric rolling process for band shape ratio h0/D = 0.124. The study was conducted to determine the differences in the impact factor of asymmetry in the band bending after leaving the deformation zone and the power parameters of rolling process. Introduction of single asymmetry by varying the peripheral speed of the work rolls does not have an effect on reduction of force parameters values. Based on the survey, it was found that introduction of a second asymmetry by varying the diameter of the work rolls allows to lower rolling force and rolling power, it also allows to obtain a flat band after rolling process.

Physical Simulations of the Controlled Rolling Process of Plate X100 with Accelerated Cooling

The research presented in the current paper was carried out for the experimental steel designed for plate which meets the requirements for grade X100 according to API5L. Physical modeling of the rolling process was carried out using the GLEEBLE 3800 simulator. The tested steel is fine-grained constructional steel for making tubes for gas pipelines with the working pressure higher than 15 MPa. The fine-grained structure guarantees excellent plastic properties as well as high impact toughness. After rolling the steel should obtain the minimal yield point of 690 MPa and tensile strength over 760 MPa.