海洋用结构钢在NaCl溶液中疲劳短裂纹的扩展

本文用海洋平台结构钢A537CL1的单边裂纹样品,在空气和3.5％ NaCl水溶液中进行了腐蚀疲劳短裂纹扩展实验,比较不同裂纹长度及环境介质对疲劳短裂纹扩展行为的影响。结果表明,在门槛值附近,对于相同的应力强度因子范围,短裂纹扩展速率比长裂纹扩展快。短裂纹扩展的门槛值随裂纹长度的减小而减小。与空气介质相比较,盐水对疲劳短裂纹扩展加速的程度远大于长裂纹。

GROWTH OF SHORT CRACKS OF A537CL1 STEEL UNDER FATIGUE LOADING IN 3.5% NaCl SOLUTICN

The effects of environmental media, both in atmosphere and in 3.5% NaCl aqueous solution, on the growth of short cracks in comparison with the long ones have been investigated under fatigue loading on the specimens of single- edge crack about 0.05--0.15 mm for A537CL 1 steel. The growth rate of short cracks is faster than those of long ones around the threshold stress intensity. The thresh- old stress intensity for short crack growth decreases with decreasing crack length. The acceleration effect of the salt water, as compared with atmosphere environ- ment, on the growth of short cracks under fatigue is much greater than that on the growth of long cracks.