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研究了奥氏体不锈钢Ⅲ型试样的氢致开裂和应力腐蚀。结果表明,动态充氢时Ⅲ型试样也能发生氢致滞后断裂,且裂纹沿原缺口平面形核和扩展。从而可获得宏观平滑的扭转断口,但断口上存在少量沿45°面的二次裂纹,一系列实验表明动态充氢能促进奥氏体不锈钢室温蠕变,故在恒扭矩下充氢能使扭转角不断增大,直至试样被扭断。奥氏体不锈钢Ⅲ型试样在42％沸腾MgCl_2溶液中也能发生应力腐蚀开裂,且裂纹在与缺口平面成45°的平面上形核和扩展。实验表明,无论是Ⅰ型还是Ⅲ型,应力腐蚀的门槛值均比氢致滞后断裂门槛值要低,例如K_(ⅠSCC)/K_(ⅠX)=0.18,K_(ⅠH/K_(ⅠX)=0.58,K_(ⅢSCC)/K_(ⅢX)=0.13 K_(ⅢH)/K_(ⅢX)=0.62。
Hydrogen induced cracking and stress corrosion of type III austenitic stainless steel were studied. The results show that Hydrogen-induced delayed fracture can also occur on Type Ⅲ specimens during dynamic hydrogen charging, and the nucleation and propagation of cracks along the original notched plane. Thus obtaining a macroscopically smooth torsional fracture. However, there are a few secondary cracks along the 45 ° fracture surface. A series of experiments show that dynamic hydrogen charging can promote the creep of austenitic stainless steel at room temperature. Therefore, hydrogen charging under constant torque can reverse The angle continues to increase until the specimen is broken. Austenitic stainless steel type III specimens also undergo stress corrosion cracking in 42% boiling MgCl 2 solution, and the nuclei nucleate and expand in a plane at 45 ° from the notched plane. The experimental results show that the thresholds of stress corrosion are lower than those of hydrogen induced hysteresis fracture, for example, type Ⅰ or type Ⅲ, such as K Ⅰ SCC / K × I x = 0.18 and K IH / K × I x = 0.58 , K_ (ⅢSCC) / K_ (ⅢX) = 0.13 K_ (IIIH) / K_ (IIIX) = 0.62.