基于响应面法设计的TC4钛合金激光焊复合活性剂优化

Optimization of compound active agent for laser welding of TC4 titanium alloy based on response surface methodology

焊缝熔深和焊接成形系数是影响焊接效率的主要因素,文中采用Design-Expert V12的响应面法对TC4激光焊进行复合活性剂配方设计,研究活性剂对TC4激光焊焊缝熔深和成形系数的影响规律。结果表明,基于响应面法设计出Na_(2)SiF_(2)与Y_(2)O_(2),Na_(2)SiF_(2)与TiO_(2),Y_(2)O_(3)与TiO_(2)对焊缝熔深起正交互作用,Na_(2)SiF_(6)与Y_(2)O_(3)和Na_(2)SiF_(6)与TiO_(2)对成形系数起正交互作用,涂覆优化的复合活性剂焊接TC4钛合金,焊缝熔深比未涂覆活性剂的增加了1.49倍,成形系数达到0.494;涂覆复合活性剂Ⅰ既能显著细化焊缝粗大的柱状晶,又能细化晶内针状马氏体α’相,热影响区宽度有所减小,焊缝表面成形质量优良,其焊接接头抗拉强度比未涂覆活性剂提高约5.53%,断后伸长率提高约1.5%。

In this paper,the response surface method of Design-Expert V12 was used to design the compound active agent formula for TC4 laser welding,and the effect of active agent on the weld penetration and forming coefficient of TC4 laser welding was studied.The result showed that based on response surface method,the designed Na_(2)SiF_(6)and Y_(2)O_(3),Na_(2)SiF_(6)and TiO_(2),Y_(2)O_(3) and TiO_(2) had positive interaction on weld penetration,and Na_(2)SiF_(6)and Y_(2)O_(3),Na_(2)SiF_(6)and TiO_(2) had positive interaction on forming coefficient.TC4 titanium alloy was welded with optimized compound active agent,the weld penetration increased by 1.49 times than that of uncoated active agent,and the forming coefficient reached 0.494.Compound active agentⅠcould not only significantly refine the coarse columnar crystal of the weld,but also refine theα’phase of acicular martensite within the grain.The width of the heat affected zone was reduced,and the forming quality of the weld surface was excellent.The tensile strength of welded joint was about 5.53%higher than that of the uncoated active agent,and the elongation after fracture was about 1.5%higher than that of the uncoated active agent.