药芯焊丝CO2气体保护焊接2205不锈钢焊缝的组织与耐腐蚀性能

选取一组优化的焊接参数对2205双相不锈钢板进行药芯焊丝CO2气体保护焊,对比研究了焊缝和母材的显微组织和耐腐蚀性能。结果表明:焊缝与母材均由铁素体和奥氏体两相组织组成,且铁素体体积分数相近,分别为42.4%,49.5%;在FeCl3溶液中浸泡腐蚀时,随着FeCl3溶液浓度的增大和温度的升高,焊缝及母材的点腐蚀速率均增大,且焊缝的点腐蚀速率高于母材的,说明焊缝的耐点腐蚀性能更差;焊缝的自腐蚀电位、容抗弧半径、钝化膜电阻均低于母材的,说明焊缝的耐电化学腐蚀性能更差,但焊缝腐蚀时形核阻力较大,腐蚀坑不易扩展。

Microstructure and Corrosion Resistance of 2205 Stainless Steel Weld by CO2 Gas-Shielded Arc Welding with Flux-Cored Wire

The CO2 gas-shielded arc welding with a flux-cored wire was carried out on 2205 duplex stainless steel plate with a set of optimized welding parameters.The microstructure and corrosion resistance of the weld and the base metal were studied.The results show that the weld and the base metal were both composed of a duplex microstructure of ferrite and austenite,and had similar volume fractions of ferrite,which was 42.4%and 49.5%,respectively.The pitting corrosion rates of the weld and the base metal increased with the rise of FeCl3 solution concentration and temperature during immersion corrosion in FeCl3 solutions.The weld had higher pitting corrosion rates than the base metal,indicating the weld had poorer corrosion resistance.The free corrosion potential,capacitive radius and passive film resistance of the weld were all lower than those of the base metal,indicating the corrosion resistance of the weld was lower.However,the nucleation resistance of the weld during corrosion was large,leading to an uneasy extension of the corrosion pit.