This work aimed to develop a microstructure-predicting methodology (MPM) using coupled physical-FEM-thermodynamic simulation to predict the influence of cooling time from 800 to 500 °C (t_8/5 – 15, 30, 80, and 210 s) on the microstructure and mechanical behavior of the coarse grain heat-affected zone (CGHAZ) of a Cr-Mo low alloy steel welded joint. The MPM was experimentally validated. The MPM certainly predicted that the increase of t_8/5 caused a remarkable change in CGHAZ microstructure (martensite and bainite to ferrite with aligned and non-aligned martensite-austenite-carbide M-A-C) and also decreases the Vickers microhardness. The MPM and experimental data show that the use of welding parameters that increases t_8/5 (reducing the cooling rate) can jeopardize the welded joint behavior. Besides, the MPM proved to be a suitable tool for estimating the microstructure and microhardness of the CGHAZ.

这项工作旨在开发一种使用物理-FEM-热力学耦合模拟的微结构预测方法（MPM），以预测800至500°C（t _8/5 – _15、30、80和210 s）的冷却时间的影响。Cr-Mo低合金钢焊接接头粗晶粒热影响区（CGHAZ）的组织和力学性能 MPM已通过实验验证。MPM肯定地预测，t _8/5的增加会引起CGHAZ显微组织的显着变化（马氏体和贝氏体到具有排列和不排列的马氏体-奥氏体-碳化物MAC的铁素体），并且还会降低维氏显微硬度。MPM和实验数据表明，使用焊接参数会增加t _8/5（降低冷却速度）会危害焊接接头的性能。此外，MPM被证明是评估CGHAZ显微组织和显微硬度的合适工具。