Effect of thermal cycles on ferrite content of austenitic stainless steel

The properties of austenitic stainless steel weld metals are strongly influ enced by the duplex structure of austenite and ferrite. The objective of th e present study was to investigate the effect of thermal cycles on the ferr ite content in austenitic stainless steel weld metal, and to explore the fe rrite-austenite solid state transformation of austenitic stainless steel we ld metal. The results indicate that the peak temperature, cooling rate, and number of thermal cycles have a significant effect on ferrite content in t he austenitic stainless steel weld. As the cooling rate increases, or the n umber of thermal cycles decreases, the amount of retained ferrite is increa sed at room temperature. New delta ferrite phase can be formed if the rehea ting peak temperature is above the optimum gamma solvus temperature of aust enitic stainless steel, nod this new delta ferrite can be retained under ra pid cooling conditions.