论文部分内容阅读
通过宏观检查、金相组织检验、硬度检验、化学成分检验和力学性能测试,对某火电厂1Cr18Ni9Ti不锈钢高温再热器管进行了失效分析。结果表明:开裂管子内壁存在大量大小和深浅不一的凹坑类原始加工缺陷,而无缺陷位置管子组织和室温力学性能正常,化学成分符合标准要求。管子内壁大量凹坑导致应力集中,并使管子剩余壁厚小于最小需要壁厚,这样管子强度不足。在管子弯制过程中,凹坑底部形成微裂纹,裂纹不断扩展,最终导致管子在最薄弱的弯头外弧面发生脆性开裂。
The failure analysis of 1Cr18Ni9Ti stainless steel high temperature reheater tube in a thermal power plant was carried out by macroscopic examination, microstructure test, hardness test, chemical composition test and mechanical property test. The results show that there are a large number of original defects in the inner wall of the cracked tube with different sizes and depths, and the tube structure and room temperature mechanical properties without defects are normal. The chemical composition meets the standard requirements. A large number of pits on the inner wall of the pipe lead to stress concentration, and the remaining wall thickness of the pipe is smaller than the minimum required wall thickness so that the pipe strength is insufficient. During tube bending, microcracks form at the bottom of the dimples and the cracks continue to expand, ultimately resulting in brittle cracking of the tube at the outermost arc of the weakest elbow.