8 mm中厚板TC4钛合金TIG焊数值模拟及实验研究  

Numerical Simulation and Experimental Research on TIG Welding of 8 mm Medium and Heavy Plate TC4 Titanium Alloy

作　　者：方静 祁文军[1] 胡国玉[1] FANG Jing;QI Wenjun;HU Guoyu(School of Mechanical Engineering,Xinjiang University,Urumqi 830017,China)

机构地区：[1]新疆大学机械工程学院,乌鲁木齐830017

出　　处：《材料导报》2023年第22期151-156,共6页Materials Reports

基　　金：新疆维吾尔自治区自然科学基金(2021D01C051)。

摘　　要：本工作采用数值模拟方法对TC4钛合金非熔化极惰性气体保护电弧焊(TIG)进行焊接工艺优化,并结合实验进行验证,在最优工艺下分析接头的显微组织及力学性能。结果表明:通过数值模拟仿真得到的TC4钛合金8 mm中厚板TIG焊焊接在电压为20 V、电流为130 A、焊接速度为3 mm/s时,接头母材能完全焊透,结合实验验证在此工艺参数下可得到成形良好无缺陷的焊接接头;分析不同冷却速度下形成的组织形态,焊缝区冷却速度可达788℃/s,主要有柱状晶及少量等轴晶,且晶内形成大量针状α′马氏体,显微硬度平均值达到390.96HV,是母材TC4硬度380HV的1.11倍,热影响区的粗晶区冷却速度达475℃/s,为β晶粒中析出的片层状α相,显微硬度平均值为328.19HV,低于母材硬度,热影响区的细晶区冷却速度为67℃/s,晶粒尺寸小于粗晶区,形成极少量的马氏体组织,显微硬度平均值为363.69HV。数值模拟结合实验验证进行工艺优化,可减少实验次数,是进行焊接工艺优化的有效手段。This work aims to optimize the argon arc welding process of TC4 titanium alloy by numerical method,analyse the microstructure features and mechanical properties of the welding joint under the optimum technological.The modeling results were validated with the verification experiment.The results show that the base metal of the welding joint can be fully penetrated with the voltage of 20 V,the current of 130 A,and the welding speed of 3 mm/s by argon arc welding of 8 mm plate of TC4 titanium alloy,well-formed and defect-free welded joints can be obtained under these process parameters combined with experimental verification.Different microstructure states that can be formed at different cooling rates,the cooling rate in the fusion zone can reach 788℃/s,mainly columnar crystals and a few equiaxed crystals,and a large number of needle-likeα′martensite formed in the crystal.And the average hardness is 390.96HV,which is 1.11 times that of the base metal.The cooling rate of the coarse-grained zone in the heat-affected zone reaches 475℃/s,there are lamellarαphase precipitated in theβgrains and the average hardness is 328.19HV,which is lower than that of the base metal.The cooling rate of the fine-grained zone in the heat-affected zone reaches 67℃/s,the grain size is smaller than that in the coarse-grained zone and a very small amount of martensite is formed,the average hardness is 363.69HV.The conclusions may provide a design reference of welding technology for TC4 titanium alloy.

关 键 词：TIG焊接 TC4钛合金 热循环曲线 显微组织 数值模拟 

分 类 号：TG444.1[金属学及工艺—焊接]