X90管线钢的抗氢致开裂性能

Microstructure and Resistance against Hydrogen Induced Cracking of X90 Pipeline Steel

目前有关X90管线钢抗H2S性能的研究报道较少。为此,采用NACE TM 0284-2003方法对X90和X80管线钢进行氢致开裂(HIC)试验以对比研究其抗HIC性能,论述了氢致开裂的机理,并分析了X90管线钢的微观组织和化学成分对氢致开裂的影响。结果表明:X90管线钢的抗HIC性能较X80管线钢差,X90钢的热影响区与焊缝区的抗HIC性能比母材好;X90钢易产生Mn的偏析,且C会加剧其偏析,同时Cr的碳化物析出使氢鼓泡易在此处产生,2种因素均导致X90钢的抗HIC性能降低;适当控制微观组织比例,降低C含量,在保证提高X90管线钢强度的同时,严格控制Mn和Cr的含量,可以提高其抗HIC性能。

Hydrogen induced cracking(HIC) tests of X90 and X80 pipeline steels were conducted according to standard method of NACE TM 0284- 2003.The resistance of the two kinds of pipeline steels against HIC was compared,and their HIC mechanisms were discussed.Moreover,the effect of microstructure and chemical composition of X90 steel on the HIC behavior was investigated.Results showed that X90 pipeline steel exhibited poorer anti-HIC ability than X80 pipeline steel,and the heat- affected zone and welding joint of the X90 pipeline were superior to the steel bulk in terms of the anti-HIC ability.X90 steel was liable to Mn segregation,while C enhanced its segregation and chromium carbide precipitation resulted in hydrogen blistering.The anti-HIC ability of the X90 steel,fortunately.could be improved by properly adjusting its microstructure and C content in association with the strict control of its Mn and Cr content thereby guaranteeing its strength.