P11耐热钢窄间隙焊接接头组织分布特征与性能分析

针对P11耐热钢采用钨极氩弧自动焊进行多层单道窄间隙焊接，对接头进行金相试验和力学性能测试，重点探讨并总结了窄间隙钨极氩弧多层单道焊接接头组织的分布特征及与硬度的对应关系。测试结果表明：接头中的填充焊道组织为铁素体和屈氏体，粗、细晶区呈交互层叠状分布，组织较母材细小，硬度高于母材；盖面焊道组织以回火马氏体和粒状贝氏体为主，组织粗大且出现了网状屈氏体，硬度较填充焊道组织高；焊接热影响区中铁素体+珠光体组织呈条带状分布，与焊缝内组织相近。接头拉伸试验结果表明接头各区域抗拉强度较为均匀，与组织分析结果相吻合。冲击试验结果表明接头各区域冲击吸收能量均满足设计要求。

Microstructure Distribution Characteristic and Property Analysisof Narrow Gap Welded Joint of P11 Heat Resistant Steel

The P11 heat resistant steel was welded by the narrow gap automatic TIG method,and the bead was filled using multi-layer single pass technology.Then the metallographic structures were observed and mechanical properties were tested,and the relationship between microstructure distribution characteristic and micro-hardness was particular searched.The results show that the filling bead consists of ferrite and troostite,and the coarse and fine grained regions are appeared alternately.When compared with base metal,the microstructure is finer and micro-hardness is higher.The cosmetic bead is mainly composed of coarse lath martensite and granular bainite while reticular troostite emerged,and the micro-hardness is higher than that of filling bead.In heat affected zone (HAZ) of filling bead,ferrite and pearlite with a banding distribution are observed,which is similar with the filling bead.In the thickness direction,the ultimate tensile strengths of top and bottom are almost the same,which is corresponding with microstructure distribution characteristic.And the impact tests show that absorption energy can meet all the requirements.