GC-4高强钢腐蚀疲劳裂纹扩展的研究

CORROSION FATIGUE CRACK GROWTH BEHAVIOR OF GC-4 HIGH STRENGTH STEEL

本文研究了GC-4高强度钢的腐蚀疲劳裂纹扩展行为。考虑了不同热处理制度、不同环境(实验室空气、3.5%NaCl溶液、蒸馏水)和不同应力比(R=0.1,0.3)的影响。研究表明,300℃等温的疲劳及腐蚀疲劳裂纹扩展性能远优于180℃等温制度,在盐水和蒸馏水环境下裂纹扩展速率明显加快,随着应力比的提高,环境影响加剧。利用扫描电镜对试样断口形貌进行了分析并讨论了腐蚀疲劳机理。

The fatigue Crack growth rates of GC-4 high strength steel with two heat treatment processes were studied under two stress ratios (R=0.1,0.3)in laboratory air, 3.5％ sodium chloride(NaCl) Solution, and stilled water environments. The results revealed that the resistance to fatigue and corrosion fatigue crack growth rates of 300℃ isothemal-quenching heat treatment was superior to 180℃. Salt water and stilled water environments assisted crack growth significantly. The influences of aqueous environments on crack growth are enhanced by increasing stress ratio. The mechanism of corrosion fatigue was mainly investigated by the SEM cxamination of fracture surface.