Thermal deformation behavior and processing maps of nickel-free high nitrogen austenitic Cr18Mn16Mo2.5N0.83Nb0.15 stainless steel

Abstract

The nickel-free high nitrogen austenitic Cr18Mn16Mo2.5N0.83Nb0.15 stainless steel was fabricated by electroslag remelting technology. The high-temperature thermal deformation behavior of as-fabricated steel was investigated using Gleeble-1500D type thermal-mechanical simulation testing machine under the condition of the temperature range from 950 °C to 1100 °C and the strain-rate range from 0.01s−1 to 1.0s−1. The constitutive equation containing polynomial of as-fabricated steel was built to describe stress function containing the variable of deformation temperature and strain-rate based on Arrhenius equation. The Q value is 448.915 kJ mol−1 by computing using the experimental data obtained from the thermal deformation tests. The thermal forging temperature should be higher than 1050 °C and the strain-rate below 1s−1 based on the thermal processing maps.