国产X70管线钢的硫化氢应力腐蚀性能及其焊接性

Sulfide stress corrosion cracking and weldability of domestic X70 pipeline steels

摘要: 针对在含H₂S的介质中,不同成分条件的国产管线钢H₂S应力腐蚀开裂(Sulfide stress corrosion cracking,SSCC)性能、焊接性分别采用恒载荷法及插销试验法进行了研究;对插销试样断口进行了电子显微镜分析。试验结果表明,不同C、Mn、P含量的国产X70管线钢在相同的试验条件下具有不同的SSCC断裂时间与断裂应力。其原因主要是由于它们的Mn、P元素含量的不同引起的,而不是C元素;采用LINCOLNE6010焊条,预热70℃时的临界应力σ_cr=630 MPa,不预热时的σ_cr=610 MPa,即预热可以使国产X70管线钢的临界应力明显提高;插销试样的断口形貌是由解理断裂、准解理断裂和韧窝断裂构成的混合型断口。

Abstract: Constant load test and implant test were utilized to study the sulfide stress corrosion cracking (SSCC) in the sulfide solution and weldability of domestic X70 pipeline steels. Electronic microscopic testing was used to analysis the fracture morphology in implant tests. The results suggested that it is element Mn, P, not element C that lead to domestic X70 pipeline steels with different chemical compositions have different resistance to SSCC. The σ_cr (critieal stress) of the joint produced by LINCOLN E6010 welding rod is 630 MPa, 610 MPa with preheating(70℃) or without preheating respectively. The appearance of implant fracture is charaterized by civility, permit cleavage and cleavage.