H. Dyja

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.

The influence of the thickness of a bimetallic layer (18G2A + 0H18N10T) on the distribution of the relative flow rate in asymmetrical rolling

Abstract Numerical analyses for asymmetrical rolling of bimetallic plates have been performed in this work. The Forge 2D programme based on the finite element method has been applied in the computer simulations. The material used for considerations was 18G2A+0H18N10T (according to Polish Standards). The research was carried out for three various bimetallic layers thickness HT/HM=6/22, 10/18 and 14/14. The simulations for rolling of bimetallic plates were carried out for 10, 20 and 25% relative reduction. The optimal value of asymmetry ratio of the rolls speed was investigated. The ratio of rotational speed of the rolls that allows the obtaining of a straight band is known as the optimal. This is connected with a linear distribution of relative flow rate at the exit from the roll gap. The uniform flow of the bimetallic layers gives the possibility of obtaining a straight band.

Theoretical and experimental analysis of plates asymmetric rolling

Abstract A bending of a front end of a plate in a process of rolling in a reversing finishing mill has been analyzed in the work. An asymmetric process of rolling has been investigated by application of finite element method. An effect of a plate entry angle and other process parameters for curvature of a rolled plate has been described. Results of investigations of the asymmetric process of a plate rolling in a quarto stand of a rolling plant of Czestochowa Steel Work are presented. An implementation of the asymmetric proces in industrial conditions has alowed for getting the higher quality of the final product, the output increase and high economical effects.

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.

Theoretical Modelling of Metallurgical Defect Closing-Up Processes During Forming a Forging

Computer modeling using an FEM-based program, i. e. Forge 2008, was carried out. Laboratory modelling of the process of free hot forging in shaped anvils was conducted to close up metalurgical defects. Results obtained fromthe simulation modeling were processed by using a commercial statistical package, i.e. Statistica 6.0 PL The influence of the anvil shape and main parameters of the forging process on closing up metalurgical defects were determined. On the basis of the investigation carried out, the optimal values of main forging technological parameters and suitable groups of anvils to be used in particular forging stages are proposed for the elimination of metalurgical defects.

Determination Of Slitting Criterion Parameter During The Multi Slit Rolling Process

The rolling of rods with slitting of the strip calls for the use of special mathematical models that would allow for the separating of metal. A theoretical analysis of the effect of the gap of slitting rollers on the process of band slitting during the rolling of 20 mm and 16 mm‐diameter ribbed rods rolled according to the two‐strand technology was carried out within this study. For the numerical modeling of strip slitting the Forge3® computer program was applied. The strip slitting in the simulation is implemented by the algorithm of removing elements in which the critical value of the normalized Cockroft ‐ Latham criterion has been exceeded. To determine the value of the criterion the inverse method was applied. Distance between a point, where crack begins, and point of contact metal with the slitting rollers was the parameter for analysis. Power and rolling torque during slit rolling were presented. Distribution and change of the stress in strand while slitting were presented.

Application of the three-high skew rolling to magnesium rods production

Abstract The main purpose of this paper was the theoretical and laboratory analysis of 20 mm AZ31 magnesium alloy rods rolled in the three-high skew rolling mill process. For this, the numerical analysis was carried out by using Forge2011® computer program. Based on the theoretical results, the distributions of stress, strain and temperature were determined. It turned out that rolling on the three-high skew rolling mill allows the rolling process to be run with high elongation factors in a single pass, which makes the skew rolling more economical and reduces the losses for roll mechanical working. After the rolling in three-high skew rolling mill, the rods of 20 mm diameter were straight, without surface defects and a low ovality.

Analysis of the Aluminum Bars in Three-High Skew Rolling Mill Rolling Process

One of the modern methods of production of round bars is the process of rolling in three-high skew rolling mill. This method enables the production of bars with both standard materials as well as hard deformation materials. In this paper, the results of theoretical and laboratory research of the 20 mm aluminum A1050 round rods rolling in three-high skew rolling mill process are presented. The numerical analysis was carried out upon applying the Forge 2011® software package. Based on the theoretical research, the stress, strain and temperature distribution during the rolling process were determined. In order to verify the numerical results, rolling aluminum rods were explored in laboratory conditions.

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.