TC4钛合金低真空20kW激光焊接特性研究

Study on Low Vacuum 20 kW Laser Welding Characteristics of TC4 Titanium Alloy

为探究厚壁钛合金在不同环境压力下的激光焊接特性,采用低真空激光焊接技术对Ti6Al4V合金进行非熔透焊接试验研究,分析了亚气氛环境压力对钛合金万瓦级激光焊接焊缝成形、焊接气孔、等离子体羽、熔池及匙孔的影响规律,并探讨亚气氛环境可以改善万瓦级激光焊接质量的可能原因。研究结果表明:环境压力对焊缝熔深、熔池宽度及匙孔上表面开口直径的影响存在一个临界区间即104 Pa数量级,达到临界区间后焊缝熔深会显著增加,熔池宽度、孔口直径显著减小。造成这种现象的可能原因之一是等离子体羽的突变,亚气氛环境激光焊接等离子体羽被明显抑制,对激光束能量传输的干扰效应降低。

In order to explore the laser welding characteristics of thick-walled titanium alloy under different ambient pressures,the non-penetration welding test of Ti6Al4V alloy was carried out by low vacuum laser welding technology.The influence of sub-atmosphere ambient pressure on the weld formation,welding porosity,plasma plume,molten pool and keyhole of laser welding of titanium alloy was analyzed,and the possible reasons why sub-atmosphere environment can improve the quality of laser welding of ten thousand watts were discussed.The results show that there is a critical range of 104 Pa for the influence of ambient pressure on weld penetration,weld pool width and keyhole upper surface opening diameter.After reaching the critical range,the weld penetration will increase significantly,and the weld pool width and orifice diameter will decrease significantly.One of the possible reasons for this phenomenon is the sudden change of plasma plume.The plasma plume of laser welding in sub-atmosphere environment is obviously suppressed,and the interference effect on laser beam energy transmission is reduced.