A Study of the Effect of Local Plastic Strains on the Delayed Fracture of the Heat-Affected Zone Metal of High-Strength Low-Alloy 14KhGN2MDAFB Steel

Abstract

Local plastic strains, which develop at the initial stages of delayed fracture of the heat-affected zone of high-strength low-alloy 14KhGN2MDAFB steel with σ0.2 ≥ 700 MPa, have been investigated using x-ray diffraction analysis. It has been found that the local plastic strain values increase with time of holding under long-term loading. In this case, the maximum local plastic strain occurs in the vicinity of the fatigue crack tip. The kinetics of the local plastic strain development during thermal cycling is affected by the specimen cooling rate W6/5.