超高频脉冲GTAW工艺特性分析

发布时间：2018-04-20 23:22

本文选题：超高频脉冲GTAW + Ti-Al-V钛合金　；参考：《机械工程学报》2016年02期

【摘要】：基于5 mm厚的Ti-6Al-4V钛合金平板,分别采用常规钨极氩弧焊(Conventional gas tungsten arc welding,C-GTAW)和超高频脉冲钨极氩弧焊(Ultra high frequency pulsed GTAW,UHFP-GTAW)工艺,选用相同平均电流(60 A)进行焊接,同时利用FLUKE Ti400红外热像仪对熔池中心温度进行实时监测,分别对电弧定点燃烧时、以50 mm/min焊速移动时采集的熔池中心温度进行分析。由测量结果可知,与相同条件下C-GTAW相比,UHFP-GTAW作用下的熔池中心温度最大值增加了10~40 K,表明该工艺具有更高的能量密度。分析1.5 mm钛合金对接工艺试验的组织性能测试结果发现,焊缝区细小均匀的针状α'马氏体形成的网篮组织含量增加,热影响区组织α'相呈现短且小的针状且排列更为致密,可改善接头的拉伸力学性能、疲劳性能。UHFP-GTAW焊缝的伸长率最小增幅为30%,断面收缩率最小增幅为50%,疲劳寿命至少增加2倍。
[Abstract]:Based on Ti-6Al-4V titanium alloy plate with thickness of 5 mm, conventional gas tungsten arc welding process (C-GTAW) and ultra-high frequency pulsed TIG arc welding (Ultra high frequency pulsed GTAWUHFP-GTAW) were used respectively, and the same average current of 60A was used for welding. At the same time, the FLUKE Ti400 infrared thermal imager is used to monitor the temperature of the molten pool center in real time. The temperature of the molten pool center is analyzed when the arc is burning at a fixed point and the welding speed is 50 mm/min. The measured results show that the maximum temperature of molten pool under the action of UHFP-GTAW is increased by 1040 K compared with that of C-GTAW under the same conditions, which indicates that the process has a higher energy density. By analyzing the microstructure and properties of 1.5 mm titanium alloy, it is found that the fine and uniform needle-like 伪 'martensite in the weld zone increases the content of the net basket, and the 伪' phase of the heat-affected zone presents a short, small needle-like and compact arrangement. The tensile mechanical properties of the joints can be improved. The minimum increase of the elongation of the joint is 30, the minimum increase of the shrinkage of the section is 50, and the fatigue life of the joint is at least 2 times longer than that of the UHFP-GTAW weld.
【作者单位】：北京航空航天大学机械工程及自动化学院;
【基金】：国家自然科学基金(51405007) 航空科学基金(2011ZE51061)资助项目
【分类号】：TG457.19

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