焊前预热对回填式搅拌摩擦点焊过程的影响  

Effect of Pre-heating on Welding Process of Refill Friction Stir Spot Welding

作　　者：赵华夏 李登常 郭晓娟 吕赞[2] ZHAO Huaxia;LI Dengchang;GUO Xiaojuan;LYU Zan(AVIC Manufacturing Technology Institute,Beijing 100024,China;College of Aerospace Engineering,Shenyang Aerospace University,Shenyang 110136,China)

机构地区：[1]中国航空制造技术研究院,北京100024 [2]沈阳航空航天大学航空宇航学院,辽宁沈阳110136

出　　处：《热加工工艺》2021年第21期124-128,132,共6页Hot Working Technology

摘　　要：在回填式搅拌摩擦点焊的摩擦阶段,搅拌工具需与母材摩擦产热使母材软化,减少在随后下扎阶段套筒下扎的阻力。为了使摩擦阶段的母材在短时间内充分软化,提出焊前预热的辅助工艺。使用Fluent软件对点焊过程进行仿真,研究不同预热温度对温度演变规律及材料流动行为的影响。结果表明,预热有助于提高焊点温度峰值,减少下扎阶段阻力;预热至227℃时,焊点处材料达到400℃的时间减少至3s,有效地减少摩擦阶段的时间。同时,提高预热温度使得材料流变应力进一步降低,扩大了材料高速流动区域范围。At the friction stage during the refill friction stir spot welding(RFSSW),the welding tool needs to produce friction heat generated between this tool and the base material,so the base material is softened and then the resistance undergone by tool at the plunge stage is reduced.In order to sufficiently soften the base material in a relatively short time at the friction stage,a pre-heating assisted process before welding was put forward.The Fluent software was used to simulate the RFSSW process,and the effects of pre-heating temperature on temperature evolution and flow behavior of material during welding were investigated.The results show that the pre-heating can heighten the peak temperature during welding,thereby reducing the resistance of welding tool at the plunge stage.When the pre-heating temperature increases to 227℃,the time when the temperature of the welding spot reaches 400℃only reduces to 3s,thereby the time of friction stage effectively shortens.Moreover,increasing the pre-heating temperature can further decrease the flow stress of material,which enlarges the high velocity flow region of material.

关 键 词：回填式搅拌摩擦点焊 铝合金 焊前预热 温度 流场 

分 类 号：TG453[金属学及工艺—焊接]