摘要
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。
Through macroscopic examination, metallographic examination, hardness test, chemical composition test and mechanical property test, the failure analysis of iCrl 8Ni9Ti stainless steel high temperature heater tube in a thermal power plant was carded out. The results show that there are a large number of original pits processing defects with different sizes and depths in the inner wall of cracking tube. The pipe microstructure and room temperature mechanical properties are normal, and the chemical composition meets the requirements of the standard. Large number of pits in the inner wall of tube leads to stress concentration, and the residual wall thickness of the pipe wall thickness is less than the minimum required wall thickness, so the strength of the tube is insufficient. Micro-cracks form at the bottom of the pit during the process of tube bending and the cracks gradually expand, which eventually leads to the brittle cracking in extrados of the weakest elbow.
出处
《热加工工艺》
CSCD
北大核心
2017年第7期254-257,共4页
Hot Working Technology
