A unified methodology for determination of the formability characteristics by plastometric torsion test

The paper presents a unified procedure for determining the characteristics of technological plasticity of materials in a torsion test, ensuring repeatability and reproducibility of experimental results.The description of the procedure is preceded by an analysis of research results obtained independently at two research centers: TU Bergakademie Freiberg and Silesian University of Technology.The experiments were conducted on specimens made of austenitic steel 0H18N9 (1.4301), maintaining identical test parameters, namely strain rate and temperature.The remaining test conditions reflected the specific characteristics of the equipment and specimen geometries used at each research center.The analysis of plastometric test results indicates that at a temperature of 900 °C, the maximum flow stress values were obtained at the Silesian University of Technology.In the remaining temperature range, from 1000 °C to 1150 °C, the highest flow stress values (σp) were recorded at TU Bergakademie Freiberg.The highest values of limiting strains (εg and εp), across the entire temperature range, were obtained from the experiments conducted at the Silesian University of Technology.The obtained experimental results and the comparative analysis performed confirm the validity of developing a unified methodology for determining the characteristics of technological plasticity in torsion tests.The proposed methodology systematizes the experimental procedure, from the selection of specimen geometry to the acquisition of test results and the method of converting recorded measurement data.The paper presents a unified procedure for determination of the formability characteristics, which ensures good repeatability and reproducibility of results.A methodology for performing the experiment as well as a method for converting experimental data into the flow stress -strain relationship are suggested.