经济型铁素体不锈钢焊接接头组织与耐蚀性能

Microstructure and corrosion resistance of welding joints of economic ferritic stainless steel

采用ER-309焊丝焊接了TCS345,T4003,Nirosta 4003,JFE410RW四种铁素体不锈钢,用金相方法分析了四种母材、接头的显微组织,通过电化学极化曲线测量,对母材和焊接接头的耐腐蚀性能进行了评价.结果表明,TCS345和T4003铁素体不锈钢与Nirosta 4003和JFE410RW铁素体不锈钢的主要区别是钛和锰含量偏低,尤其是钛含量少,导致TCS345和T4003铁素体不锈钢的晶粒长大倾向较Nirosta 4003和JFE410RW铁素体不锈钢的明显.铁素体不锈钢焊接接头存在较大的热影响区,热影响区的组织与母材晶粒相比,其晶粒明显粗大;TCS345铁素体不锈钢的晶粒长大严重,Nirosta 4003和JFE410RW铁素体不锈钢的铁素体晶粒尺寸比TCS345略小,晶粒长大不明显.在1mol/L Na2SO4溶液中,TCS345和JFE410RW不锈钢母材的腐蚀性能优于T4003和Nirosta 4003.

TCS345,T4003,Nirosta 4003 and JFE410RW ferritic stainless steels were welded by ER-309 welding wire in this paper.The microstructure of their base metal and joint were analyzed by metallographic approach,and the corrosion resistance of base metal and joints was evaluated by electrochemical corrosion tests.The experimental results demonstrated that,compared with that of Nirosta 4003 and JFE410RW,low content of Ti and Mn elements were found in TCS345 and T4003 ferritic stainless steels,especially the low content of Ti,which resulted in the obvious grain growth of TCS345 and T4003 ferritic stainless steels.Moreover,the welding joints of ferritic stainless steels exhibited big heat affected zone(HAZ).Compared with the microstructure of base metal,the HAZ area showed obvious large grains.As far as TCS345 is concerned,obvious grain growth is observed.In the case of Nirosta 4003 and JFE410RW,they exhibited smaller size of grain than TCS345.In 1mol/L Na2SO4 solution,the corrosion resistance of TCS345 and JFE410RW is better than that of T4003 and Nirosta 4003.