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本文旨在研究断裂力学用于评定在中性盐溶液中高强度钢的应力腐蚀开裂抗力的应用。在综合考虑了测定腐蚀介质中静载荷下裂纹无扩展界限(K_(ISCC))时所遇到的主要困难后,研究了与试验条件和溶液的物理化学性能有关的因素对应力腐蚀开裂行为的影响。本研究指出了试样的清洁度,疲劳裂纹和试样加载方法等条件对试样的持续时间和再现性是有影响的。溶液的物理化学特性对裂纹扩展的不同阶段都有影响。盐浓度和温度对裂纹扩展速率也有影响,氧含量的增加缩短了孕育期。因此,如果不特别谨慎地应用楔开加载试验方法,在很多情况下就不可能测定出K_(ISCC)。为此,提出了两种解决方法。其中最主要的一种方法是,使用对深裂纹有效的新的函数式来计算应力强度因子K_I。
The purpose of this paper is to study the application of fracture mechanics to assess the stress corrosion cracking resistance of high strength steels in neutral salt solutions. After considering the major difficulties encountered in the determination of the crack without crack under static load in a corrosive medium (K ISCC), the effects of factors related to the test conditions and the physicochemical properties of the solution on the stress corrosion cracking behavior influences. This study points out that the cleanliness of the sample, the fatigue crack and the loading method of the sample have influence on the duration and reproducibility of the sample. The physicochemical properties of the solution have an effect on the different stages of crack propagation. Salt concentration and temperature also have an effect on the crack growth rate, and the increase of oxygen content shortens the incubation period. Therefore, it is not possible to determine K_ (ISCC) in many cases unless the wedge loading test is applied with particular caution. To this end, proposed two solutions. One of the most important of these is to calculate the stress intensity factor K_I using a new function that is valid for deep cracks.