焊接工艺对双金属复合管对接焊缝晶间腐蚀的影响

为了保证双金属复合管对接焊焊缝的耐腐蚀性能，结合双金属复合管对接焊的特点与特殊要求，从焊材的选取和焊接工艺参数的设计出发，验证了不同焊接工艺对复合管对接焊焊缝晶间腐蚀的影响。结果显示，实芯焊材正常焊接工艺下，焊缝的晶粒度与母材相当，没有出现腐蚀坑和晶间腐蚀弯曲开裂现象；药芯焊材及大热输入焊接工艺下，焊缝均出现不同程度的腐蚀。试验结果表明，双金属复合管在对接焊时最好选择与覆层材质相当的实芯耐蚀合金焊材，同时，要注意焊接热输入量的控制和内部惰性气体的保护。

Influence of Different Welding Processes on Intergranular Corrosion ofBimetal-lined Pipe Butt Weld

In order to ensure the corrosion resistance of bimetal-lined pipe butt weld，combined with the characteristics and special requirements of bimetal-lined pipe butt welding，based on selection of welding material and design of welding parameter，the influences of different welding processes on intergranular corrosion of bimetal-lined pipe butt weld were verified. The results showed that grain size of solid wire under normal welding process was equivalent to the base metal’s without etch pit and intergranular corrosion bending and cracking；under flux-cored wire with great heat input welding process，the different degree of weld corrosion was occurred. The test results indicated that corrosion resistant alloy solid wire，which was similar to coating material，was the best choice for bimetal-lined pipe butt welding，and the control of welding heat input and internal inert gas protection should be paid attention.