TC4钛合金高真空电子束焊接工艺研究

Study on High Vacuum Electron Beam Welding Process of TC4 Titanium Alloy

对TC4钛合金薄板进行高真空电子束焊接,结合室温拉伸试验和硬度试验,研究了焊接接头的显微组织及性能。结果表明,焊缝和热影响区的组织内部均析出了针状的α＇马氏体,焊缝中心单位面积内析出的该相比热影响区较多。随着焊接速度的增大,接头抗拉强度和断面收缩率均先增大后减小。焊接接头的显微硬度分布为距离焊缝中心越远,硬度越小。焊缝的显微硬度比热影响区硬度平均高25~30 HV,热影响区的显微硬度比母材硬度平均高20~30HV。在电子束流为17 m A、聚焦电流为498 m A、焊接速度为1000 mm/min下焊接,焊接效果较好。

TC4 titanium alloy sheets were welded by using high vacuum electron beam welding and the microstructure and properties of the joints were analyzed combined with tensile test and hardness test, The results show that needle α＇martensite is precipatated in the weld and heat affected zone（HAZ）. Additionally, α＇ phase precipitated in unit area at weld center is biggger than that in HAZ. With the increase of welding speed, the tensile strength and percent reduction in area both increase firstly and then decrease. The microhardness distribution of welded joint is that the farther the position away from the weld center is, the smaller the hardness is. The microhardness of the weld is 25-30 HV higher than that of heat affected zone,and the microhardness of the HAZ is 20-30 HV higher than that of base metal. When the electron beam current is 17 m A, the focus current is 498 m A and the welding speed is 1000 mm/min, it can get good welding quality.