In the present work, DH36 steel and AISI 1008 steel sheets were joined using friction stir welding (FSW) process to investigate the influence of the rotational speed, traverse speed, and tool offset on temperature distribution, z-force, microstructure, and mechanical properties of the welded specimens. At a traverse speed (v) of 50 mm/min with a rotational speed (ω) of 600 rpm and tool offset of 2 mm, the maximum impact toughness and hardness were obtained due to higher grain refinement. The transverse tensile test specimens fractured in the weaker material (i.e., AISI 1008 steel) and exhibited the ultimate tensile strength values at least on the level of the weaker material. The impact toughness and hardness were highly dependent on the grain size variation. The effect of pitch ratio (ω/v) on grain size variation was more as compared with that on tool offset. Increasing the pitch ratio reduced the grain size and improved the impact toughness and hardness. Stir zone exhibited the acicular-shaped bainitic ferrite in DH36 steel and Widmanstatten ferrite grains in AISI 1008 steel. The higher hardness values were observed in thermo-mechanically affected zone of both steels due to significant grain refinement. Increasing the rotational speed and decreasing the traverse speed result in a higher welding temperature, which reduced the z-force.

中文翻译：

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DH36船用钢–AISI 1008钢异种搅拌摩擦焊工艺参数控制的实验研究

在目前的工作中，采用摩擦搅拌焊（FSW）工艺将DH36钢板和AISI 1008钢板连接在一起，以研究转速，横移速度和刀具偏移量对温度分布，z力，显微组织和机械性能的影响。焊接的样品。以50 mm / min的移动速度（v）和旋转速度（ω））600 rpm和2 mm的刀具偏移，由于更高的晶粒细化度而获得了最大的冲击韧性和硬度。横向拉伸试样在较弱的材料（即AISI 1008钢）中断裂，并且至少在较弱的材料水平上显示出极限抗拉强度值。冲击韧性和硬度高度依赖于晶粒尺寸变化。螺距比的影响（ω / v）在晶粒尺寸变化上要比在刀具补偿上更大。增大螺距比可减小晶粒尺寸，并改善冲击韧性和硬度。搅拌区在DH36钢中呈现出针状贝氏体铁素体，在AISI 1008钢中呈现出Widmanstatten铁素体晶粒。由于显着的晶粒细化，在两种钢的热机械影响区均观察到较高的硬度值。增大旋转速度和减小横移速度会导致较高的焊接温度，从而降低Z力。