Influence of Temperature Change on the Energy Parameters during Round Bars Rolling Process

The paper presents results of experimental studies on the effect of non-uniform temperature distribution over the metallic charge length on the energy parameters change during round bars rolling process. Experimental tests were conducted on the D370 Continuous Shape Mill in industrial works. From the tests carried out, it has been found that the main cause of occurrence of the non-uniform distribution of temperature over the charge length is the process of heating the metallic charge in the walking beam furnace. During rolling of bars from metallic charge with non-uniform temperature distribution over its length, changes in friction conditions in the zone of contact between the band and the rolls and in the plastic properties of steel being rolled occur. For decrease temperature during metallic charge rolling process about 100 °C (Fig. 2) in walking beam furnace, increase of rolling torque and total rolling power about 30% during rolling process metallic charge in first continuous shape mill stand was observed.

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.

Metallographic Analysis of Bimetallic Ribbed Bars Produced from Feedstock Mill of the Surfacing Method TIG and of the Method ESS LM Received

A considerable increase in interest in using corrosion resistant steel clad ribbed bars in the construction industry has been observed in recent years. This is owing to the particular properties of these bars, namely high durability and rigidity, good mechanical properties, and high corrosion resistance. Bimetallic ribbed bars can be manufactured in medium-size and small shape mills from previously produced bimetallic feedstock. The manufacture of ribbed bars with an outer layer of corrosion-resistant steel is a complicated process that involves numerous technological problems. The most important of which include the obtaining of bimetallic feedstock with the adequate strength of the bond in the region of junction between the core and the clad layer, and assuring the even plastic flow of both bimetallic layers during the process of rolling in the elongating and forming passes in the shape Mill. Failure to meet these conditions may result in a delamination of the bimetallic band during rolling or the formation of other defects, which will disqualify the finished bimetallic bar [1÷4]. In the paper the metallographic analysis of bimetallic ribbed bars steel-steel resistant to corrosion produced from bimetallic feedstock mill of the surfacing method TIG and of the method ESS LM received. Surfacing method TIG and ESS LM method are the affirmed processes the receipt the bars plated is characterizing the large strength of bond two different metals. Moreover, in this study, the authors present the bond strength of interface of bimetallic joint of the cross section on the test bar. The core was of the constructional carbon steel C45E and the clad layer was made of the corrosion resistant steel X2CrNi18-10. Plastometric tests were performed on a Gleeble 3800 plastometer owned by the Institute of Modelling and Automation of Plastic Working Processes, using strain rates of 0.1 s-1, 1.0 s-1 and 10 s-1 respectively [1÷3, 7].

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.