Choy Leejon, Kang Myungchang, Jung Dongwon
Graduate School of Convergence Science, Pusan National University, Busan 46241, Korea.
Faculty of Mechanical, Jeju National University, Jeju 63243, Korea.
Materials (Basel). 2022 Apr 1;15(7):2602. doi: 10.3390/ma15072602.
In recent years, friction stir welding (FSW) of dissimilar materials has become an important issue in lightweight and eco-friendly bonding technology. Although weight reduction of low-rigidity parts has been achieved, the weight reduction has been minimal because high-rigidity parts such as chassis require the use of iron. Considering the difficulty of welding a pipe shape, it is necessary to understand the effect of process parameters on mechanical performance. As a result of the study by various process parameters affecting the joint between aluminum and steel in the shape of a pipe, it can be seen that the tool penetration depth (TPD) has the most important effect on the tensile shear load (TSL). However, the effect of TPD on intermetallic compound (IMC), which has the most important influence on fracture, has not been well established. In this study, the effect of process parameters on IMC thickness and TSL in FSW of A357 cast aluminum and FB590 high tensile steel was investigated to reduce the weight of the torsion beam shaft of an automobile chassis. After the FSWed experiment, measurements were performed using an optical microscope and scanning electron microscopy (SEM) to investigate the microstructure of the weld. The formation of an IMC layer was observed at the interlayer between aluminum and steel. TPD is a major factor in IMC thickness variation, and there is a direct relationship between IMC thickness reduction and TSL increase, except for certain sections where the welding speed (WS) effect is large. Therefore, in order to improve mechanical properties in friction stir lap welding of aluminum and steel for high-rigidity parts, it is necessary to deepen the TPD at a level where flow is dominant rather than heat input.
近年来，异种材料的搅拌摩擦焊（FSW）已成为轻量化和环保连接技术中的一个重要问题。尽管低刚度部件的减重已经实现，但由于底盘等高刚度部件需要使用铁，减重效果一直很有限。考虑到管材焊接的难度，有必要了解工艺参数对力学性能的影响。通过对影响管材形状的铝和钢之间接头的各种工艺参数进行研究，结果表明，工具穿透深度（TPD）对拉伸剪切载荷（TSL）的影响最为重要。然而，TPD对金属间化合物（IMC）的影响，而IMC对断裂有着最重要的影响，目前尚未得到很好的确立。在本研究中，研究了工艺参数对A357铸造铝和FB590高强度钢搅拌摩擦焊中IMC厚度和TSL的影响，以减轻汽车底盘扭力梁轴的重量。在搅拌摩擦焊实验之后，使用光学显微镜和扫描电子显微镜（SEM）进行测量，以研究焊缝的微观结构。在铝和钢的中间层观察到IMC层的形成。TPD是IMC厚度变化的主要因素，除了焊接速度（WS）影响较大的某些部分外，IMC厚度的减小与TSL的增加之间存在直接关系。因此，为了提高铝和钢在高刚度部件搅拌摩擦搭接焊中的力学性能，有必要在流动占主导而非热输入的水平上加深TPD。
