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.
Materials Science and Engineering A, A339: 133-135