Effects of temper-embrittling heat treatment on ductile failure in high-strength low-alloy steel

Abstract

The effects of a temper-embrittling heat treatment on the ductile failure of the low-alloy steel En30A are found to be (a) a large reduction in crack initiation strain, as measured by δ_c the critical COD, (b) a smaller reduction in upper shelf energy, measured in notched-bar impact tests, and (c) a decrease in tensile ductility. This behaviour is explained in terms of the effect which the weakening of carbide/matrix interfaces by the presence of segregated impurity atoms has on the ductile fracture process in this steel.