Термоупругий анализ комплекса Atmospheric Chemistry Suite орбитального зонда Trace Gas Orbiter миссии ExoMars
The results concern roll pass design for rolling a round bar of a 20mm diameter from a 55mm diameter input. Concerning materials, this roll pass design must cover a wide range of steels, from low-carbon micro-alloyed steels to stainless steels. The roll pass design proposal takes into consideration lower plasticity of certain steels. The comparison was enabled by suggesting two roll pass designs. The classical oval-round roll pass design, where the maximum extension coefficient is set to 1.55 in oval and 1.22 in round grooves. The second roll pass design uses a combination of smooth part of the roll (curves) and round roll passes. Distribution of the extension coefficient in individual passes is similar to that of oval-round series. The paper also compares values of energy-force parameters calculated analytically using the method of finite elements. If we compare the distribution of temperature, stress and size of the grain, it is proved that the oval-round roll pass designs are the best as far as the balanced distribution of the above-mentioned values is concerned. The roll pas design combining smooth part of the roll with a round part does not achieve such balance. However, its advantage lies in far lower requirement for the needed length of the working part of the roll. Five passes are carried out on the smooth part of the roll, which considerably cuts down the required length of the roll body. Therefore it is this variant that will be used in the laboratory of wire rolling created within the project RMSTC.
Hot forming behavior of high-strength automotive steel HC420LA is the main objective of this work. Uniaxial and plane strain compression tests were performed at Gleeble 3800 testing machine. A comparison of these types of tests was realized. The material constitutive constants were found as well as the dependences of peak and stady-state stresses on strain rate and temperature. It is shown that the testing technique have an impact on the stress-strain curves obtained by its implementation, this can lead to a mismatch of results of computer simulation of metal forming technologies. In order to evaluate such mismatches a finite element simulation of bar rolling process using the material properties obtained by different testing methods is considered.