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采用CO₂保护低合金钢焊丝焊接C4镍基合金/X60钢异种金属.并研究了焊缝的组织与耐蚀性.结果表明:靠近C4镍基合金熔合线附近出现含有奥氏体组织的未混合区，X60钢熔合区组织无明显未混合区出现;在C4镍基合金未混合区内Cr、Ni元素含量较高，从焊缝中央到X60钢熔合线，Cr元素含量明显减少，Ni元素含量增加;C4镍基合金熔合区和X60钢熔合区的耐蚀性优于焊缝区；形成腐蚀膜对基体保护作用也比焊缝区好

This work is with regard to the weld of dissimilar metallic materials C4 alloy and X60 steel by means of CO₂ shielded welding and with filler of a low alloy steel.Microstructure in the fused zones in the two matrixes just adjacent to the joint lines (F_C4for C4 side and F_X60 for X60 side)and weld joint(W_j)it self was observed by OM.The distribution of Cr and Ni element was analyzed by EDS in the weld joint.The corrosion behavior of the above three zones was examined in a CO₂ containing solution by PARSTAT 2273.The obtained results showed that the zone F_C4of 350 μm wide was consisted of double phases of austenite and ferrite/austenite,where rich in Cr and Ni.On the contrary,there is no obvious change in phase constituent in the zone F_X60.From the center of weld joint to the joint line adjacent to X60,the Cr content decreased,but the Ni content increased.The polarization resistance of the Wj is lower than that of F_C4 and F_X60. However the difference of corrosion densities at the three zones is few.Slower polarization reaction in low frequencies indicated the scales on zones of F_C4 and F_X60,as well as the relevant matrixes provided a better protection than that on zone W_j.