超超临界锅炉末级过热器异种钢焊接接头断裂原因分析与预防  

Fracture Analysis and Prevention of Dissimilar Steel Welded Jointof Last Stage Superheater of USC Boiler

作　　者：林琳[1] 唐勇 殷尊[1] 孟永乐[1] 李生文[1] LIN Lin;TANG Yong;YIN Zun;MENG Yongle;LI Shengwen(Xi'an Thermal Power Research Institute Co.,Ltd.,Xi'an 710054 China;China Resources Power(Wenzhou)Co.Ltd.,Longgang 325800,China)

机构地区：[1]西安热工研究院有限公司,陕西西安710054 [2]华润电力(温州)有限公司,浙江龙港325800

出　　处：《热加工工艺》2023年第7期142-145,共4页Hot Working Technology

摘　　要：对某电厂开裂的超超临界锅炉末级过热器F91/TP310HNbN异种钢焊接接头进行分析,包括宏观形貌检查、几何尺寸测量、金相组织检验、扫描电镜断口形貌分析和维氏硬度试验。结果表明:异种钢焊接接头开裂是焊缝的化学成分、组织、力学性能和物理性能与不锈钢侧母材差异较小,而与F91侧母材差异较大,导致F91侧焊缝熔合线附近成为整个接头的薄弱环节,再加上多种应力作用共同造成的。预防异种钢焊接接头早期失效应选用更为合适的焊材进行焊接,并在机组停机时加强金属监督检验。By means of macroscopic examination,geometric measurement,OM analysis,fracture morphology analysis,Vickers hardness test,the cracked F91/TP310HNbN welded joints of last stage superheater of USC boiler in a power plant was investigated.The results show that the chemical composition,microstructure,mechanical properties and physical properties of the weld have no big difference from those of the stainless steel base metal but have big difference from those of the F91 base metal,as a result,the F91 side weld fusion line becomes the weak link of the whole joint,under a variety of stress concentration,the cracking of the welded joint occurs.In order to prevent the early failure of dissimilar steel welded joints,more suitable welding materials should be selected,and metal supervision and inspection should be strengthened when the unit is shut down.

关 键 词：超超临界锅炉 异种钢焊接接头 开裂 早期失效 

分 类 号：TG441.7[金属学及工艺—焊接]