In this research, numerical as well as experimental analysis on friction stir welding (FSW) of dissimilar steels, i.e. DH36 steel and AISI 1008 steel, was performed. A 3D heat transfer FE model based on Abaqus/CAE using Fortran code via DFLUX subroutine was developed to investigate the effect of FSW parameters (i.e. rotational speed and traverse speed) on temperature distribution during the welding. It was observed that decreasing the traverse speed, increasing the rotational speed and shoulder diameter enhanced the peak temperature due to higher heat input. Based on the experimentally obtained sound quality welding parameters, the FE model was successfully validated with a maximum percentage error of 5.57% for peak temperature. Experimental results revealed that the higher heat generation reduced the grain size by increasing the rotational speed and decreasing the traverse speed. The inhomogeneous hardness distribution was observed across the weld cross section due to grain size variation. The higher grain refinement at a rotational speed of 600 rpm with a traverse speed of 70 mm/min produced the maximum value of the hardness and impact toughness. The tensile weld samples were fractured in the base metal zone (i.e. AISI 1008 steel) and experienced the tensile strength within the range of the AISI 1008 steel. The microstructure in the SZ exhibited the Widmanstatten ferrite in AISI 1008 steel and acicular-shaped bainite ferrite in DH36 steel. EDS analysis of the fractured surface of impact specimens confirmed the embedment of tungsten carbide particles in the weld zone due to the tool wear.

在这项研究中，对DH36和AISI 1008异种钢的搅拌摩擦焊（FSW）进行了数值和实验分析。建立了一个基于Abaqus / CAE的3D传热有限元模型，该模型通过DFLUX子例程使用Fortran代码进行了研究，以研究焊接过程中FSW参数（即转速和横向速度）对温度分布的影响。据观察，由于更高的热量输入，降低移动速度，增加旋转速度和肩部直径会提高峰值温度。根据实验获得的声音质量焊接参数，成功验证了有限元模型，峰值温度的最大百分比误差为5.57％。实验结果表明，较高的热量产生通过增加旋转速度和降低横移速度来减小晶粒尺寸。由于晶粒尺寸的变化，在整个焊接横截面上观察到不均匀的硬度分布。在600 rpm的转速和70 mm / min的横向移动速度下更高的晶粒细化度产生了硬度和冲击韧性的最大值。拉伸焊缝样品在母材区域（即AISI 1008钢）断裂，并且抗拉强度在AISI 1008钢范围内。SZ的显微组织在AISI 1008钢中显示出Widmanstatten铁素体，在DH36钢中显示出针状贝氏体铁素体。