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本文用断裂力学的方法对30CrMnSiA结构钢在盐雾介质和室温空气下的疲劳裂纹扩展特性进行了初步研究。 用紧凑拉伸试样,在应力强度因子△K=70～200kg/mm~3/~2范围内,其试验结果表明:试验初期,盐雾介质中的裂纹扩展速率比室温空气中的要高,并随着试验频率的降低而急剧增加,这种情况通常是氢脆机制造成的。当盐雾介质中的试验进行到20～40小时以后,由于裂纹表面腐蚀产物的堆积,裂纹扩展速率逐渐减缓,甚至低于室温空气下的da/dN曲线。在试验的最后阶段,由于应力强度因子幅值的增大,上述两种介质中的裂纹扩展速率趋于接近。
In this paper, the fatigue crack propagation properties of 30CrMnSiA structural steels under salt spray medium and room temperature air are studied by means of fracture mechanics. The test results show that the crack propagation rate in salt fog medium is higher than that in room temperature air at the beginning of the test in the range of stress intensity factor △ K = 70 ~ 200kg / mm ~ 3 / ~ 2. , And increased sharply with decreasing test frequency, a condition usually caused by a hydrogen embrittlement mechanism. When the test in salt spray medium was carried out for 20 to 40 hours, the crack growth rate gradually slowed down due to the accumulation of corrosion products on the crack surface, even lower than the da / dN curve under room temperature in air. In the final stage of the experiment, the crack growth rates in the two media tended to approach due to the increase in the magnitude of the stress intensity factor.