K. Laber

The Analysis of Al-Cu Bimetallic Bars Bond Layers Joined by the Explosive Method

The paper presents investigation results for obtaining a semi-finished product in the form of round Al-Cu bimetallic bars by the explosion method. The systems and technological parameters of explosion welding were selected in such a manner as to obtain finished bimetallic bars of an outer diameter of approx. 22 mm and a copper area fraction of the bimetal cross-section of approx. 15 and 30%. In this work was made an analysis of microstructure changes and the microhardness distribution on the cross-sections of the stock materials. There were also made tests of layers connections quality by determining the maximum shear stress on the joint boundary. The results show that the explosive cladding method guarantee a permanent connection of copper layers and aluminum core.

Analysis of industrial conditions during multi-stage cooling of C70D high-carbon steel wire rod

Abstract An analysis of the parameters of multi-stage controlled strip cooling during the process of rolling of 5.5 mm-diameter C70D high-carbon steel wire rod has been made in this publication. Investigations included also the analysis of the flow rate of the cooling medium and its pressure in the devices for accelerated and controlled cooling of the strip directly in the rolling line, as well as in the STELMOR line. The investigations carried out within the study have determined the cooling capacity of the accelerated strip cooling devices for specific (preset) cooling conditions. The scope of the investigations also encompassed the analysis of the effect of the employed cooling conditions on the temperature distribution and on the properties and microstructure of the steel studied. Moreover, physical modeling of the currently applicable technology of rolling the investigated steel grade was also performed.

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.

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.

Theoretical and Experimental Analysis of the Cooling Ability of Device for the Plain Round Bars Accelerated Cooling Process

The paper presents the results of the numerical modelling and industrial research of the cooling ability of the device for the round plain bars accelerated cooling process. Research were carried out for one of the bar rolling mill technological conditions in a few variants. The paper purpose was determination of the cooling ability of device for accelerated cooling process to checking possibility of the using this device in the rolling line, during normalizing rolling process. Investigation results elaborated in the paper made the basis for determination of the heat exchange coefficients between cooled band and water. In the next stage of this paper numerical modeling of the normalizing rolling process with accelerated cooling of band in the final stage of the rolling process was carried out. In this investigation heat exchange coefficients between band and cooling medium (water), which were determinated with allowance of cooling possibilities of investigated device for band accelerated cooling were used. From the obtained results it was found that in the analysed bar rolling mill it is possible to decrease the band average temperature to about 900 °C, which is required during 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.

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.

Determination of the Cracking Susceptibility of Steel S355J2G3 during the Continuous Casting Process

The paper presents the results of physical modelling aimed at determining the cracking susceptibility of the selected steel grade under conditions characteristic of the continuous casting process. The material used for investigation was steel grade S355J2G3 [1]. For a study on the physical modelling of the continuous steel casting process, the GLEEBLE 3800 [2, 3], a metallurgical process simulator, was employed. The obtained results allowed establishing conditions for a continuous steel casting process that could cause cracks to form in the material being cast. Research on one of technological conditions for steelworks was carried out taking into account the problem of cracking during rolling in the initial group of the bar rolling mill.

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.

Numerical Modelling of the Cooling Ability of Device for the Plates Accelerated Cooling Process

The paper presents results of the numerical modelling of the plates accelerated cooling process after the rolling process. Research were carried out for one of the plate rolling mill technological conditions. Presented in the paper research were done for a few variants for X70 steel grade. As a result of the carried out research temperature distribution on the cross section of the cooled plates for the analyzed variants of the accelerated cooling process were obtain.