Determination of Critical Factors Affecting on Hydrogen Induced Cracking and Type I Sulfide Stress Cracking of High Strength Linepipe Steel

摘要

The metallurgical factors affecting HIC and SOHIC of high strengthlinepipe steel are investigated and the cracking resistance is correlatedwith diffusible hydrogen. Internal cracks were initiated at elongatedMnS and TiNb(C,N) cluster regardless of the cracking mode. Increasein diffusible hydrogen content by cathodic charging or applying theexternal load makes the steel more susceptible to the cracking and itcan imply that both of critical factors, inclusion clusters as well asdiffusible hydrogen in the steel, should be carefully controlled toimprove the cracking resistance.