长时运行T91/G102焊接接头组织性能分析

对长时运行前后T91/G102异种钢焊接接头的显微组织及显微硬度进行了研究.结果表明,长时运行对T91侧的显微组织影响不大,而对焊缝、G102侧的热影响区及母材的显微组织有明显的影响.焊后G102侧正火区形成的细小的粒状贝氏体组织经长时运行后有大量细小的片形M6C型碳化物析出.G102母材典型的板条状贝氏体组织经长时运行后则转变成了无明显贝氏体板条特征的回火贝氏体组织并伴有链状碳化物出现.显微硬度分析表明,运行后其T91侧显微硬度同运行前基本相当,焊缝及G102侧母材的显微硬度低于运行前,而G102侧热影响区的显微硬度却高于运行前的状况.

Microstructure and property of long-time run T91/G102 dissimilar steel welded joint

The microstructure and micro-hardness have been studied on the T91/G102 dissimilar steel welded joints before and after a long-time run.The results showed that the long-time run had little effect on the T91 HAZ microstructure,but had a definite effect on weld and the G102 HAZ microstructure.After the long-time run,the fine particle bainite in the welding normalized zone kept its fine microstructure and at the same time precipitated lots of fine chip-like carbides,which was proved to be M6C carbide by TEM analyses.The lath bainite in the original matrix was transformed into tempered bainite without remaining any lath feature and precipitated lots of the block ferrite grains and chain-shape carbides instead.The results also showed that the micro-hardness on the T91 HAZ almost kept the same after its long-time run and the micro-hardness on the weld and G102 matrix dropped down.However,the micro-hardness in the heat affect zone of G102 went up unexpectedly.