Effect of reversion heat treatment on the mechanical properties of thermally embrittled UNS S32760 duplex stainless steel

Abstract

Duplex Stainless Steels contain very high chromium contents (19-30% by weight) and exhibit excellent corrosion resistance and extremely good mechanical properties. Embrittlement of duplex stainless steels due to precipitation of αʹ upon prolonged exposure in the temperature range of 280°C to 500°C has been a serious limiting factor for its long term usage in the nuclear industry, where the operating temperatures of cooling pipes is around 300°C. In this investigation, the effect of reversion heat treatment on the mechanical properties of a thermally embrittled duplex stainless steel has been studied. The specimens were solutionized, aged and then reversion treated for varying periods. The aged specimens showed significant increase in tensile strength and decrease in ductility in comparison to the ones in solutionized condition. The specimens which were reversion treated showed marginal decrease in tensile strength and significant increase in ductility after 5 minutes of holding time. As the holding time increased, the tensile strength rapidly decreased and ductility increased initially up to 30 minutes of reversion, after which there was no significant change in strength and ductility. © (2015) Trans Tech Publications, Switzerland.