Effect of the Tempering Temperature on the Structure and the Mechanical Behavior of VNS9-Sh TRIP Steel with a High Martensite Content

The phase composition and the mechanical properties of a 0.35-mm-thick strip made of austenitic–martensitic VNS9-Sh (23Kh15N5AM3-Sh) TRIP steel are studied after tempering at 450–900°C. The surface layer in the steel in the initial state contains almost 100% strain-induced martensite. Tempering at a temperature above 450°C is shown to cause the reverse martensitic transformation and a significant decrease in the strength properties.