Abstract A computer simulation of the α/γ phase transformation in a multi-pass weld of duplex stainless steel (DSS) was made to predict the distribution of the γ phase fraction in the heat-affected zone (HAZ). The kinetic equations including rate constants of the dissolution behavior as well as the precipitation behavior of the γ phase were determined by an isothermal heat treatment test. Based on the kinetic equations determined, the distribution of the γ phase fraction in a multi-pass weld of lean DSS was calculated by applying the incremental method combined with a heat conduction analysis of the welding process. The γ phase fraction was reduced in the higher temperature HAZ; however, that in the reheated HAZ was increased and recovered to the base metal level. Microstructural analysis revealed that the calculated results of the γ phase fraction in the multi-pass weld were consistent with experimental ones. Based on the computer prediction, the microstructural improvement welding (“reheat bead welding”) process, an analogous concept to the temper bead welding technique, is newly proposed for recovering the γ phase fraction in the weld just as in the as-welded situation.

中文翻译：

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双相不锈钢多道焊中α/γ相分数的计算机预测及显微组织改进焊接工艺

摘要 对双相不锈钢 (DSS) 多道焊缝中的 α/γ 相变进行计算机模拟，以预测热影响区 (HAZ) 中 γ 相分数的分布。动力学方程包括溶解行为的速率常数以及 γ 相的沉淀行为通过等温热处理试验确定。基于所确定的动力学方程，应用增量法结合焊接过程的热传导分析，计算了贫DSS多道焊中γ相分数的分布。γ相分数在高温热影响区减少；然而，在重新加热的 HAZ 中，它增加并恢复到贱金属水平。显微组织分析表明，多道焊缝中γ相分数的计算结果与实验结果一致。基于计算机预测，新提出的微观结构改进焊接（“再热焊道焊”）工艺是一种类似于回火焊道技术的概念，用于恢复焊缝中的 γ 相分数，就像在焊接状态下一样。