Pre-Heat Treatment of Stainless Steel Before Torsion Under High Pressure
The purpose of this work is to study the effect of pre-heat treatment on the microstructure and mechanical properties of stainless austenitic steel. The heat treatment was carried out under five different conditions. The first four involved heat treatment of the material at four different temperatures ranging from 750°C to 900°C in 50°C increments. The holding time is 30 minutes, cooling in water. In addition, the fifth two-stage heat treatment was carried out, which was carried out at a temperature of500°C with an exposure of 15 minutes and then heated to 800°C with an exposure of 30 minutes and followed by slow cooling of the samples in air. Two-stage heat treatment showed a microstructure with large homogeneous, equiaxed grains. Cooling in air and heating at two temperatures for a long time allowed for the diffusion and formation of a stable microstructure of austenite in accordance with the phase diagram. Based on these findings, two-stage heat treatment was chosen as the most suitable pre-heat treatment for heat treatment of rings.