超超临界机组高温再热器出口爆管原因分析  

Analysis of tube burst at the outlet of high temperature reheater of ultra-supercritical unit

作　　者：周亚明 汤淳坡 尹少华 周龙 许尧 孙志强[2] ZHOU Ya-ming;TANG Chun-po;YIN Shao-hua;ZHOU Long;XU Yao;SUN Zhi-qiang(CHN Energy Taizhou Power Generation Co.,Ltd.,Taizhou 225327,Jiangsu pro.,China;Suzhou Thermal Engineering Research Institution Co.,Ltd.,Suzhou 215004,Jiangsu pro.,China)

机构地区：[1]国家能源集团泰州发电有限公司,江苏泰州225327 [2]苏州热工研究院有限公司,江苏苏州215004

出　　处：《焊接技术》2020年第8期96-99,I0002,共5页Welding Technology

摘　　要：文中通过对高温再热器出口开裂及未开裂的异种钢接头进行理化检测、力学性能、扫描电镜等分析,发现T92钢侧热影响区韧性不足,脆性较大;裂纹出现在热影响区细晶区,裂纹周围较大范围内可见较多蠕变孔洞,孔洞多分布于原奥氏体晶界上,孔洞连接形成微裂纹,具有明显Ⅳ型裂纹特征,查询温度记录发现该区域存在多次超温记录。其次,对高温再热器出口开裂异种钢接头区域进行结构应力分析,发现开裂焊接接头在大小头变径区,同时异种钢焊缝承受弯曲应力较大。综上可知,异种钢焊缝结构设计不当及存在多次超温现象是导致异种钢接头出现蠕变开裂失效的主要原因。In this paper, through the physical and chemical testing, mechanical properties and SEM analysis of the cracking and uncracked dissimilar steel joints at the outlet of the high-temperature reheater, it was found that the toughness of the heat affected zone on the T92 side was insufficient and the brittleness was large. The cracks appeared in the fine grain area of the heat affected zone, and there were many creep holes around the cracks in a large range,and the holes were mostly distributed on the original austenite grain boundary, and the holes were connected to form micro cracks, with obvious Ⅳ type crack characteristics. It was found to have multiple overtemperature records in this area by querying the temperature records. Secondly, the structural stress analysis of the cracking dissimilar steel joint area at the outlet of the high temperature reheater showed that the cracking welding joint was in the large and small head reducing area, and the bending stress of dissimilar steel weld was large. In conclusion, the main reason for the creep cracking failure of dissimilar steel joints was the improper design of dissimilar steel weld structure and the existence of multiple overtemperature phenomena.

关 键 词：超超临界 T92钢 HR3C钢 异种钢接头 Ⅳ型裂纹 失效分析 

分 类 号：TG142[一般工业技术—材料科学与工程]