Influence of thermal and mechanical processing on room temperature mechanical properties of nickel free high nitrogen austenitic stainless steels

Nickel free high nitrogen austenitic stainless steels with a base compositi on around 18%Cr-18%Mn and varying in C and N contents and processing condit ions were evaluated for their mechanical behaviour. A range of mechanical p roperties from high strengths to ultra high strength levels could be obtain ed. The steels develop ultra high strength levels in the as-hot worked cond ition, hot work+cold work condition and solution treated+cold worked condit ions. They show high strength levels with very good ductility and impact ro ughness levels in the solution annealed condition. The Hall-Fetch parameter s and DBTT obtained in the solution annealed condition were found to be inf luenced by the carbon content of the steel. The work hardening behaviour of the steels have been examined at various processing conditions. Nitrogen s teels with high carbon content show good mechanical properties in the solut ion treated and subsequently cold rolled conditions. In the as-formed condi tion, the high carbon steels show inferior ductility due to grain boundary lamellar nitride precipitation.