关键词: Q960E钢, 焊接变形, 残余应力, 固态相变, 数值模拟

Abstract:  A multi-pass butt-welded joint of low alloy high strength steel Q960E was prepared by equal strength matching wire and mixed gas shielded welding method. Microstructure， hardness distribution， welding temperature cycles， welding deformation and welding residual stress were observed and measured by experiments. With the consideration of the microstructure characteristics of Q960E， a thermal-elastic-plastic finite element method which considered the coupling behaviors among multiple physical fields of “thermal-microstructure-stress” was developed based on SYSWELD software platform. The material model focused on solid-state phase transformation in the heat-affected zones（HAZs）. The JMAK equation was employed to describe the austenitization processes during the heating stages， while the K-M equation was utilized to simulate the martensitic transformation processes in the cooling stages. At the same time， the transformation-induced plasticity in the cooling processes was considered based on the Leblond model. The comparison between the numerical simulation results and the experimental measurements shows that both the residual stress distribution and the welding deformation obtained by the finite element model are in a good agreement with the measured data， and the numerical simulation results also show that the solid-state phase transformation has a significant effect on the distribution and magnitude of welding residual stress in the HAZ of Q960E steel butt-welded joints. 

Key words:  , Q960E steel, welding deformation, residual stress, solid-state phase transformation, numerical simulation