CORROSION FATIGUE CRACK PROPAGATION OF MARTENSITIC AND BAINITIC GC-4 ULTRA-HIGH STRENGTH STEEL
马氏体与贝氏体组织GC—4超高强度钢的腐蚀疲劳裂纹扩展

The property and mechanism of corrosion fatigue (CF) crack propagation ofmartensitic and bainitic 40CrMnSiMoVA (GC-4) ultra-high strength steel was investigated.There is a platform region on CF crack propagation curve of the GC-4 steel with differentmicrostructure in 3.5% NaCl solution, which is similar to its stress corrosion crackingbehaviour. The CF crack propagation rate (in platform region) of martensitic GC-4 steel ismuch higher than that of bainitic one. Through fracture surface examination and theoreticalanalysis, it is revealed that hydrogen embrittlement plays an important role in the CF pro-cess of GC-4 steel.