电化学充氢条件下夹杂物对管线钢氢致开裂敏感性的影响

Effect of Inclusions on Hydrogen Induced Cracking Susceptibility of Pipeline Steels under Electrochemical Hydrogen-Charging Condition

摘要: 对X52、20、X70管线钢在0.5 mol·L-1 H2SO4 溶液中进行电化学充氢试验, 研究了钢中夹杂物形态、大小、数量、分布对管线钢氢致开裂(HIC)的影响。结果表明: X52钢的HIC敏感性远小于20钢和X70钢的; 20钢中的MnS夹杂物并不是氢致裂纹的必然形核位置, 而Al2O3、复合氧化物/铁的碳化物、硅夹杂物则是更为有害的氢致裂纹源; X70钢中以Al2O3、铁的碳化物造成的氢致开裂危害最大; 相邻夹杂物形成的裂纹源不断扩展并合成了更大的裂纹。

Abstract: Effect of morphology, size, quantity and distribution of inclusions on hydrogen induced cracking (HIC) of pipeline steels X52, 20 and X70 were studied in 0.5 mol·L-1 H2SO4 solution. The results show that the HIC sensitivity of X52 pipeline was much less than that of 20 steel and X70 steel. MnS inclusion in 20 steel was no inevitable location for hydrogen induced cracks, and Al2O3, composite oxides/Fe-C and silicon carbide inclusion were more harmful hydrogen induced crack sources. In X70 steel, the harmfulness of HIC induced by Al2O3 and Fe-C inclusion was the most, large cracks formed due to the growth and merging of the crack source at the positions of adjacent inclusions.