The Effect of Prior-Austenite Grain-Size on the Stress-Corrosion Cracking Susceptibility of A.I.S.I. 4340 Steel

摘要

Using both conventional heat-treatments and repeated rapid austenitising and quenching heat-treatments, a series of AISI 4340 steels with prior-austenite grain-sizes covering the range ASTM 7-12 were developed. The stress-corrosion cracking susceptibility of the steels in a 3.5% aqueous solution of NaCl was investigated using fatigue-precracked, plane-strain cantilever-beam specimens. The results of an electron fractographic investigation of the stress-corrosion fracture surfaces are described; the experimental results are interpreted in terms of a hydrogen-embrittlement mechanism of slow crack growth. (Author)