采用二氧化碳气体保护焊进行对接焊得到SMA490BW/Q345E异种钢T型接头，并进行590℃×3 h退火，对比研究了退火前后的组织、硬度和耐腐蚀性能。结果表明：退火前后接头均存在明显的熔合线，焊缝组织均由先共析条状铁素体、珠光体和粒状贝氏体组成；退火前，从表面向内部，焊缝组织由粗大柱状晶转变为交替出现的柱状晶和等轴晶，硬度差异较大；退火后，不同焊层的组织无明显差异，硬度分布变得均匀；退火后焊缝的腐蚀倾向减小，耐腐蚀性能提高；在NaCl溶液中周期浸润腐蚀时，退火前后焊缝表面均发生点蚀，在腐蚀后期（100 h）出现锈层龟裂现象，退火后的锈层更加致密。

Butt welding was carried out on the T-joint of SMA490BW/Q345E dissimilar steels by CO₂ shielded arc welding, and then the joint was annealed at 590 ℃ for 3 h. The microstructures, hardnesses and corrosion resistance before and after annealing were compared. The results show that before and after annealing, the weld interface was obvious in the joint, and the microstructures of the weld consisted of proeutectoid strip ferrite, pearlite and granular bainite. Before annealing, from surface to inner, the microstructure of the weld changed from coarse columnar grains to alternating columnar grains and equiaxed grains, and the hardness difference was large. After annealing, the microstructures of different layers had little difference, and the hardness distribution became uniform. The corrosion tendency of the annealed weld was reduced and the corrosion resistance was improved. During wet/dry cyclic exposure in NaCl solution, pitting corrosion occurred on the surface of non-annealed and annealed weld and the rust layer cracked in the latter stage of corrosion (100 h). The rust layer was denser after annealing.