The Effect of delta-ferrite on Fatigue Cracks in 304L Steels

Abstract

Continuous low-cycle fatigue tests of 304L stainless steel at 300 and 600 degrees C and Delta epsilon(t)=+/- 2.0% in an air environment were conducted, and the effects of the amount and direction of delta-ferrite stringers on fatigue crack initiation and fatigue life were investigated. Fatigue crack initiation was observed at the interface between delta-ferrite and a particulate matrix. The effect of delta-ferrite in 304L stainless steel on fatigue life in low-cycle fatigue was investigated. 304L stainless steel with delta-ferrite perpendicular to the loading axis has a much shorter fatigue life than that with delta-ferrite parallel to the stress axis. These phenomena are thought to be caused by the strain incompatibility at the interface between delta-ferrite and the matrix. (C) 2000 Published by Elsevier Science.