摘要
为提高电站锅炉过热器铁素体－奥氏体异种钢焊接接头的高温蠕变断裂强度和延长服役寿命，设计了用专用镍基填充材料焊接的不锈钢－镍基焊缝－耐热钢三元组合接头。通过对不同焊缝接头的高温持久性能试验及用ＳＥＭ和ＥＰＭＡ对焊缝界面组织变化的对比分析，认为在高温低应力条件下接头早期失效的主要原因是熔合区及热影响区碳、铬等元素迁移和碳化物聚集所引起的蠕变断裂。组合接头的设计方案对改善接头应力分布。
A special nickel based weld transition joint has been designed for raising the creep strength and service life of the ferritic austenitic dissimilar metal joints,which have been used in the superheaters of power plant boilers.The interface carbon diffusion,mechanical properties of joints and thermal stress on the interface area have been investigated by means of creep rupture tests,EPMA analysis.It is concluded that in the conditions of relevant temperature and low stress,carbon migration and precipitate in the fusion line and close to the area are important factors affecting creep rupture,and the nickle based weld metal transition joint can contribute to lower thermal stress and higher creep strength.
基金
省电力局94(2)技术攻关资助项目
