Andrzej Stefanik

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.

Formability of Explosive Welded Mg/Al Bimetallic Bar

The paper presents the results of physical modelling of the plastic deformation of the Mg/Al bimetallic specimens using the Gleeble 3800 simulator. The plastic deformation of Mg/Al bimetal specimens characterized by the diameter to thickness ratio equal to 1 was tested in compression tests. The aim of this work was determination of the range of parameters as temperature and strain rate that mainly influence on the plastic deformation of Mg/Al bars during metal forming processes. The tests were carried out for temperature range from 300 to 400°C for different strain rate values. The stock was round 22.5 mm-diameter with an Al layer share of 28% Mg/Al bars that had been produced using the explosive welding method. Based on the analysis of the obtained testing results it has been found that one of the main process parameters influencing the plastic deformation the bimetal components is the initial stock temperature and strain rate values.

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.

Application Of Numerical Modelling To Ribbed Wire Rod Dimensions Precision Increase

The paper presents the results of theoretical and experimental investigations of the process of rolling square ribbed wire rod designed for concrete reinforcement. Numerical modelling of the process of rolling in the finishing and pre‐finishing grooves was carried out using the Forge2005® software. In the investigation, particular consideration was given to the analysis of the effect of pre‐finished band shape on the formation of ribs on the finished wire rod in the finishing groove. The results of theoretical studies were verified in experimental tests, which were carried out in a wire rolling mill.

Influence of the Deformation Method on the Microstructure Changes in AZ31 Magnesium Alloy Round Rods Obtained by the Rolling Process

This paper presents the research results of the microstructure changes of the round rods of AZ31 magnesium alloy in the hot rolling processes. The rolling was conducted in duo mill and a three-high skew rolling mill. Numerical modelling of the AZ31 magnesium alloy round rods rolling process was conducted using a computer program Forge 2011®. The verification of the results of numerical modelling was carried out during laboratory tests in a two-high rolling mill D150 and a three-high skew rolling mill RSP 40/14. Distributions of the total effective strain and temperature during AZ31 rods rolling process were determined on the basis of the theoretical analysis. Microstructure and texture changes during both analysed processes were studied.

The Influence of the Interstand Tension of the Band on Roll Wear during the Continuous Groove-Rolling Process

Numerical modelling of the round bar rolling process, while considering the wear of passes depending on their shape, was carried out within the present work. The analysis of the rolling process was conducted thus analysing the influence of interstand tension on roll wear. For the theoretical study of the rolling process, Forge2011® was employed, which is finite element method-relying software that enables the thermo-mechanical simulation of rolling processes in a triaxial state of strain. The wear model implemented in Forge2011® permits no quantitative evaluation, but only a comparative analysis of the wear of rolls. In order to use the results of simulation employing the simplified Archard model for the quantitative evaluation of roll wear, it is necessary to define the factor of wear and the hardness of the tool as a function of temperature.

Rolling of Al-Cu Bimetallic Bars in Modified Elongating Grooves

In order to enhance the uniformity of cladding copper layer distribution over the bimetallic bar perimeter and length, the shape of the classical horizontal and vertical oval passes were modified. The rolling was carried out in the designed modified elongating grooves. The round Al-Cu bimetallic bars with an outer diameter of 22 mm and a copper layer share of 15 and 30%, after explosive cladding, were rolled on a D150 two-high shape mill. As a result of rolling in 4 passes, bars of a diameter of about 16.0 mm were obtained. By applying the modified grooves to the rolling of Al-Cu bimetallic bars, the stability of the rolling process was improved, whereby, finished bars with a uniform and tight cladding layer distribution over the core and small diameter dimensional deviations was obtained.

Numerical Modelling of Ploughshares Rolling Process from Scrapped Railway Rail

In this work, a rolling schedule has been developed, which allows the scrapped S60 railway rail to be used for further processing into semi-finished or finished products. The main purpose of the investigations was to develop the shape and dimensions the rolling grooves and to select the strains in various passes in the ploughshare rolling process. The main problem during roll pass design was the ploughshare shape which is asymmetric and has a varying thickness along the width. The developed roll pass design consist of five passes: one open shape pass, one edging pass and three closed shape passes. The first open shape pass is characterized by an unusual shape which tends to reduce the band asymmetricality in the horizontal axis in such a manner as to prevent the formation of lapping in the sharp corner areas resulting from cutting. Based on the numerical modelling it has been found that the developed roll pass design allows the production of a ploughshare of dimensions conforming to the dimensional assumptions. For the numerical modelling of the rolling process, the Forge2008® computer program was employed.

Microstructure Numerical Modelling Change during the Round Bars Rolling

In this work result of the theoretical analyses, witch the main purpose was modelling of the microstructure change during round bars rolling was presented. To determination of the austenite diameter during numerical modelling of the rolling process it is necessary to assign mathematical models of the microstructure change, relationship making the value of yield stress dependent on deformation parameters, temperature and strain range. Theoretical analysis was made in computer program Forge2008®, based on the finite-element method. An analysis was made for two cases: traditional - without accelerated cooling during rolling process and normalizing with one section of the accelerated cooling during rolling process for the ø26 mm round bars. Modification of the ø26 mm round bars rolling technology with accelerated cooling, affect the reduction of average austenite diameter, which cause improving impact resistance of the final product. Results of the theoretical analysis were verified in industrial conditions, in one of polish steelwork.