2205双相不锈钢电阻点焊接头组织与性能研究

Study on microstructure and properties of resistance spot welded joint of 2205 duplex stainless steel

采用光学显微镜等方法对2205双相不锈钢电阻点焊接头显微组织和硬度进行了观察、测试,并对比了接头和母材在酸性、中性和碱性环境中的耐腐蚀性能。结果表明:接头各区域组织均为奥氏体和铁素体,其中焊核为柱状铁素体和晶界呈条带、晶内为块状分布的奥氏体;熔合区内铁素体则为等轴晶,奥氏体以晶界呈带状分布为主;而在热影响区内的奥氏体含量与母材的相比,明显降低。硬度测试发现热影响区达到HV405左右,为接头硬度值最高区域。电化学测试表明,在酸性、中性和碱性3种环境中接头的耐蚀性均弱于母材的,其中接头在酸性环境中的耐蚀性最差,表现为其腐蚀电流密度比在碱性和中性环境中高2个数量级。接头在中性和碱性环境的耐蚀性与母材的相当。

In this paper,the microstructure and hardness of resistance spot welded joint of 2205 duplex stainless steel were investigated by OM and other technologies,the corrosion resistance of the joint and based metal in acid,neutral and alkaline solutions were also studied.The results showed that the microstructure of joint was consisted of austenite and ferrite.However,there were differences on the morphology of austenite and ferrite in different zone of joint.The microstructure of welding was consisted of columnar grain and austenite whose morphology were strip along grain boundary or intragranular blocky.The ferrite in fusion zone was equiaxed and the austenite was zonal in grain boundary.Comparing with based metal,the austenite content in HAZ was significant reduction.The maximum microhardness values in HAZ was about HV405.The electrochemical tests indicated that the corrosion resistance of joint in three environments of acid,neutral and alkaline were worse than those of based matel.And the corrosion resistance of joint in acid solution was the worst,which were observed the corrosion current density and corrosion rate were higher than those of in alkaline and neutral environment.However,there was little difference between corrosion resistance of the joint and based metal in alkaline and neutral environment.