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本文研究了纯奥氏体焊缝和奥氏体-铁素体焊缝凝固裂纹特征,探讨了铁素体防止焊缝凝固裂纹的作用。纯奥氏体焊缝裂纹断口观察表明开裂时胞状柱晶间存在残余液态金属,已结晶的胞状柱晶间未建立固相结合,在应力作用下极易开裂。少量铁素体的焊缝凝固裂纹断口上有许多小塑性区,有明显的韧窝。焊缝中铁素体多,塑性区也多。试验证明塑性区是铁素体的断裂形貌。铁素体使奥氏体胞状柱晶间形成固相结合,足够的铁素体相可防止奥氏体焊缝产生凝固裂纹。
In this paper, the characteristics of pure austenite weld and austenite-ferrite weld solidification crack were studied, and the effect of ferrite on preventing weld solidification crack was discussed. Pure austenite weld crack fracture observation shows that there is residual liquid metal between the cell of columnar cell during the cracking, and no solid phase combination has been established between the cell columnar crystalline column, which is easy to crack under the stress. A small amount of ferritic weld fracture solidification fracture there are many plastic zone, there are obvious dimples. Ferrite weld more plastic zone more. The test shows that the plastic zone is the fracture morphology of ferrite. Ferrite makes the austenitic cell between the columnar column solid phase combination, enough ferrite phase to prevent austenite weld solidification crack.