| The excellent corrosion resistance of Duplex stainless steel attracts more and more people's attention, however, due to the welding process of duplex stainless steel, the base matel is subjected to a series of thermal cycling effects, which occur complicated phase transition behavior, not only affects change of microstructure and the phase balance of duplex stainless steel, and it may bring the disadvantage of welded joints about corrosion resistance. Appropriate heat treatment after welding can restore equilibrium phase ratio effectively and make Cr,Mo and other alloy elements restore distribution betweenγandα, and making the harmful precipitates dissolved. To this end, it is great significance to study on microstructure and properties of duplex stainless steel welded joints and influence of corrosion resistance of the joint by heat treatment after welding.In this paper, through use Gas Tungsten Arc Welding (GTAW) and shielded metal arc welding (SMAW) welding 2205 duplex stainless steel docking, preparation of two joints, and at different temperature aging treatment and solution treatment for GTAW joints, research on the influence of microtructure and corrosion resistance in different welding processes and heat treatment on the 2205 duplex stainless steel joints. From the calculation proportion and observation microstructure, there are onlyαandγphase in the microstructure, and both twoαphase ratio is 40～60%, and harmful phase precipitation was not observed, indicating that the development of the welding process is suitable. The phase ratio show that the phase ratio and microstructure of GTAW joints is better than SMAW, corrosion test results also confirmed that, GTAW joint anti-pitting is better than SMAW, but their intergranular corrosion properties is nearly. By use of aging treatment on 750℃,850℃,950℃for GTAW welded joints, found that weld zone and HAZ and base matel all precipitateσphase, where precipitated the main location inα/γgrain boundary orα/αgrain boundary, with the aging time increasing,σ-phase content increasing and grow to the internal ofαphase, the corrosion resistance of samples decreases. By comparison with 750℃and 950℃, hardness of 850℃aging samples is the highest and rate of pitting is the fastest. Sample with 850℃, 60min aging and then solution heat treatment at different temperatures showed that the content ofα-phase in weld up to 40~60% again, sample corrosion resistance also increase, with suitable solution treatment for the improvement of the microstructure and improvement of corrosion resistance is significant effect.
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