某300 MW循环流化床4号机组高温再热器异种钢接头泄漏原因分析  

Leakage of Dissimilar Steel Joints in a High Temperature Reheater of a 300 MW Circulating Fluidized Bed

作　　者：裴利霞[1] Pei Lixia(Shanxi Polytechnic College,Taiyuan Shanxi 030006)

机构地区：[1]山西职业技术学院

出　　处：《现代工业经济和信息化》2019年第12期144-146,共3页Modern Industrial Economy and Informationization

摘　　要：某300 MW循环流化床4号机组高再异种钢(T91+TP321H)接头打水压时,发生开裂泄露。分别从未开裂和开裂部分的焊接接头处取样,采用宏观分析、力学性能试验、金相显微镜等对焊接接头试样进行检测和对比研究,分析其开裂原因。结果表明:焊接、焊后热处理工艺不当导致T91侧热影响区位置在整个焊接接头区域脆性较大,且T91侧熔合线碳化物析出和白色块状铁素体形成异质薄弱界面;在结构拘束应力、焊接残余应力、熔合线应力集中和振动交变应力叠加作用下导致裂纹从此处萌生和扩展,最终导致该异种钢焊接接头开裂早期失效。When a 300 MW circulating fluidized bed 4# unit high re-dissimilar steel(T91+TP321H) joint is subjected to water pressure, cracking and leakage occur. Sampling from the welded joints without cracking and cracking,respectively, using macroscopic analysis, mechanical properties test, metallographic microscope, microhardness tester,etc. The reason for its cracking is analyzed. The results show that the improper welding and post-weld heat treatment process results in the brittleness of the heat-affected zone on the T91 side in the whole welded joint region, and the carbide precipitation of the T91 side fusion line and the white bulk ferrite form a heterogeneous weak interface;stress,welding residual stress, fusion line stress concentration and vibration alternating stress cause the crack to sprout and expand from here, which eventually leads to the early failure of the dissimilar steel welded joint cracking.

关 键 词：高温再热器 异种钢接头 开裂泄漏 

分 类 号：TM621[电气工程—电力系统及自动化]