固溶处理对2205双相不锈钢FCAW接头组织及力学性能的影响

Effect of solution treatment on microstructure and mechanical properties of 2205 duplex stainless steels joint by FCAW

利用气体保护药芯焊丝焊接2205双相不锈钢,并对焊接接头进行固溶处理。采用金相显微镜、扫描电子显微镜和能谱仪对焊接接头的显微组织和断口形貌进行了观察与分析,并测试了焊接接头的冲击韧性和显微硬度。结果表明,未经处理的焊接接头熔合区较宽,主要为基体铁素体组织,并且晶粒粗大。热影响区的铁素体和奥氏体边界有少量析出相χ相,铁素体内部有颗粒物析出;焊缝区铁素体内部有σ相和γ2相析出。1 050℃固溶处理后焊接接头析出相和颗粒物消失,奥氏体组织含量提高,冲击断口等轴韧窝增多,韧性增加,硬度值降低。

2205 duplex stainless steels( DSS) were welded by gas-shielded flux-cored wire,and the welded joints are conducted by solution treatment. The microstructures and fracture morphology of weldied joints were analyzed by means of OM,SEM and EDS. The impact toughness and microhardness of welded joints were tested and analyzed systematically. The results show that the fusion zone of untreated welded joint represents a large width,and the organization is mainly composed of ferrite with coarse grains. Few of χ phases precipitate at ferrite-austenite grain boundaries and some carbide appears inside ferrite in heat affected zone( HAZ).σ phase and γ2 phase precipitate inside ferrite in weld.After 1 050 ℃ solid solution treatment,precipitated phase and carbide disappear and the proportion of austenite is higher,which results in high impact toughness and low microhardness,and the number of equiaxed dimples increase in the impact fracture surface.