Role of retained ferrite on the thermal fatigue cracking resistance in martensitic stainless steel weldment

This paper is aimed at the investigation of the role of retained ferrite within the martensitic matrix on thermal fatigue crack tendency. The experimental results show that a linear relationship does not exist between the retained ferrite content and thermal fatigue crack tendency. Based on the experimental observations, a critical ferrite content of about 31.5 vol.% is found. Retained ferrite is a beneficial factor for crack resistance when the retained ferrite is less than 31.5 vol.%. The retained ferrite becomes a harmful factor when the retained ferrite is more than this critical content.