FRACTURE ANALYSIS OF HYDROGEN-INDUCED CRACKING FOR STEEL 12Ni3CrMoV

A fracture analysis on an implant made of steel 12Ni3CrMoV containing 6ppm B was carried out of the dependence of the fracture morphology of hydrogen-induced cracking upon the hydrogen content in HAZ and upon the stress applied.It was shown that its fracture is of the quasi-cleavage(QC)crack of hydrogenembrittlement Its QC region on the fracture surface may be broadened ornarrowed with the increasing of the hydrogen content or the applied stressrespectively.The crystallographic orientation of the QC cracking in HAZ wasverified to be{110}plane by means of the etch-pit method.