Influence of tempering on microstructure and mechanical properties of Ti alloyed 13%Cr supermartensitic stainless steel

Tempering is the final heat treatment applied to martensitic steels. In conventional martensitic stainless steels or in the newly developed supermartensitic grades, the mechanical properties are strongly influenced by tempering. In the present work, several tempering treatments were performed in a Ti alloyed supermartensitic stainless steel. Tensile mechanical properties, hardness and impact toughness were measured and correlated to microstructural features. Microstructural analysis was conducted in a field emission gun scanning electron microscope and also by magnetic measurements. The ductility parameters continuously increased with tempering temperature, while yield and ultimate strength decreased. Secondary hardening and temper embrittlement were observed by hardness and low temperature impact tests respectively, while tensile tests were not sensitive to these phenomena.