焊接参数对塑流摩擦点焊接头组织和性能影响

Influence of welding parameters on the joint's microstructure and performance for friction flow spot welding

分析了流动摩擦点焊接头的微观组织和硬度分布,并对转速、下压速度和停留时间对塑流摩擦点焊接头拉伸的载荷-位移曲线、最大载荷、断裂机制进行了研究。结果表明:硬度分布沿焊缝中心对称,焊核区硬度高于母材,最低值出现在热影响区;当转速为750 r/min,下压速度30 mm/min,停留时间为15 s时,拉伸载荷最大,为6.64 kN,大多数塑流摩擦点焊接头的载荷随着位移的增加先升高后逐渐降低,为"Hook缺陷断裂",个别接头的载荷随着位置的增加升高,到达最大值后突然下降,为"界面剪切断裂"。

TFriction flow spot welding（FFSW ）, derived from friction flow welding,is a novel joint solution comparative to friction spot welding. The microstructure and hardness morphology on transverse direction was studied,moreover,the effect of rotation rate, downward speed,retention time on mechanical properties such as load-displacement curve ,maximum force ,fracture mechanism were investigated. The results showed that hardness in nugget zone was higher than that in parent metal, its distribution along transverse direction is symmetry with centerline of weld line,while the minimum value located in heat-affected zone. The tensile stress culminated at 6.64 kN, with rotation rate of 750 r/min, downward speed 30mm/min, retention time 15 s. The load increased firstly and decreased gradually with rising of displacement in majority friction flow spot joints,showing Hook fracture; while,load in other few joints increased and decreased sharply to nearly zero, demonstrating grain boundary shear fracture mode.