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本文用金相、相分析、电镜,特别是扫描电镜、电子探针等手段对铸造镍基合金焊接液化裂纹、焊接热影响区晶界经受焊接高温过程的变化进行了综合研究。提出了某些铸造镍基合金液化裂纹产生的机理:①在焊接高温下,沿晶界及晶界附近的γ+γ′共晶及其反应前缘富Zr 等低熔物熔化;④沿晶界及晶界附近的TiC 全部或部分溶解、产生“组分液化”;③这些液相沿晶界漫流形成液化晶界的部分在焊接收缩应力下开裂。根据上述裂纹产生机理调整了某铸造镍基合金成分,合金的液化裂纹倾向性得到了改善。根据液化裂纹成因,采取了防止措施,在产品焊接上取得了良好效果。
In this paper, metallurgical, phase analysis, electron microscopy, especially scanning electron microscopy, electron probe and other means of casting nickel-based alloy welding liquefied cracks, weld heat affected zone grain boundary temperature changes under high temperature process conducted a comprehensive study. The mechanism of liquefaction cracking in some nickel-base alloy castings is proposed. ① Under the high temperature of welding, γ + γ ’eutectic along the grain boundary and grain boundary and Zr-rich low-melt such as the reaction front are melted. TiC near the grain boundaries and all or part of the dissolution of the grain boundary, resulting in “component liquefaction”; ③ these liquid phase along the grain boundary to form part of liquefied grain boundary cracking in the welding shrinkage stress. According to the above-mentioned mechanism of crack generation, a cast nickel-based alloy component is adjusted, and the liquefaction crack tendency of the alloy is improved. According to the causes of liquefaction cracks, take precautionary measures, and achieved good results in product welding.