1Cr18Ni9Ti+Q235复合钢板对接焊缝组织和抗腐蚀性能分析

针对内复合不锈钢焊管制造,采用4种焊接工艺对厚度为3mm+10mm的1Cr18Ni9Ti+Q235复合钢板对接焊缝进行了自动焊接,对焊接接头进行显微组织分析、拉伸、内外弯曲、冲击试验、电化学和晶间腐蚀试验.结果表明,采用TIG焊焊接复层,复层焊缝显微组织为奥氏体加少量铁素体,在1moL/L的盐酸溶液中进行电化学腐蚀试验,其抗电化学腐蚀性能与母材复层相近,无晶间腐蚀现象.基体采用TIG焊的焊接接头,基体焊缝组织为较高强韧性的板条状马氏体,满足力学性能要求.而基体采用SAW焊的焊接接头,基体焊缝力学性能和复层焊缝抗腐蚀性能均不能满足要求.

Microstructure and corrosion resistance of butt joint of 1Cr18Ni9Ti+Q235 composite plate

Four different automatic welding techniques were applied for butt welding of the composite pipe that has a clad layer of 1Cr18Ni9Ti with a thickness of 3 mm and a substrate layer of Q235 with a thickness of 10 mm. The properties of the joint,including microstructure,tensile strength,bend strength,impact toughness,electrochemical and intergranular corrosion resistance,were evaluated. The results indicate that the phase of the clad layer welded by tungsten inert gas welding (TIG) is austenite with a little ferrite. The electrochemical corrosion resistance of the joint is similar to that of the base metal in hydrochloric acid of 1 mol/L and no intergranular corrosion is observed. The phase of the TIG welded joint of the substrate layer is martensite laths that have high strength and excellent toughness. But both the joints of the substrate layer and the clad layer welded by submerged arc welding have poorer mechanical properties and corrosion resistance,respectively.