【摘要】 对失效接头、保护侧、非阴极保护侧管体进行宏观形貌、组织形貌、腐蚀产物及力学性能进行了研究,结果表明:非保护侧管体内壁腐蚀严重,存在大量腐蚀凹坑;保护侧及非保护侧组织相同,均为铁素体+珠光体。保护侧及非保护侧试样力学性能符合标准,绝缘接头处样品抗拉强度略低于标准上限,不符合设计要求。通过腐蚀产物分析可知,绝缘接头失效主要是由于非保护侧发生二氧化碳局部腐蚀,在管体薄弱焊接处尤为严重,腐蚀由内壁发生、发展,最终形成刺漏,导致绝缘接头失效。更多还原

【Abstract】 The research results of the macro morphology, microstructure morphology, corrosion products and mechanical properties of the failed joint and the protection side and non-cathode protection side of pipe show that the inner wall of the unprotected side pipe is severely corroded, and there are a lot of corrosion pits. The tissues on the protected side and the non-protected side are the same, both are ferrite + pearlite. The mechanical properties of the samples on the protected and non-protected sides meet the standard. The tensile strength of the sample at the insulation joint is slightly lower than the upper limit of the standard, which does not meet the design requirements. The analysis of corrosion products shows that the failure of insulated joint is mainly due to the local corrosion of carbon dioxide on the unprotected side, especially in the weak welding part of the pipe body. Corrosion occurs and develops from the inner wall,and finally forms penetration and leakage, which leads to the failure of insulation joint.更多还原