火电站用T23/TP316H异种金属焊接接头服役损伤分析

通过试验研究分析了服役后的高温蒸汽管道中T23/TP316H异种金属焊接接头的微观组织、成分和氧化情况.结果表明,在540℃/17 MPa条件下服役10万h后,TP316H钢侧虽会被氧化,但未发现明显的会导致接头早期失效的潜在危险因素;T23钢侧会出现沿焊缝/热影响区界面的氧化,并出现了沿界面的开裂.T23钢与镍基焊缝...

Damage analysis of T23/TP316H dissimilar metal weld for thermal power plant after service

The microstructure,chemical composition and oxidation of the ex-service steam tube containing T23/TP316 H dissimilar metal weld were investigated to analyze damage after service.The results show that after service for 100000 hours at 540℃/17 MPa,although the TP316 H steel side is oxidized,no potential risk that may cause early failure is found;however,the T23 steel side is oxidized along the weld/heat affected zone interface and cracks along the interface is observed.The coupling interaction between interfacial oxidation damage of weld metal,the differences in thermal expansion coefficient and creep strength on both sides of the interface,and the hardness gradient near the interface is likely to induce interfacial failure and increase the early failure risk of the welded joint.In addition,some common detrimental factors such as creep and soft zone induced by carbon migration are not found at the T23 steel side,thus interfacial oxidation damage is the main damage mode of joint studied in this paper.