钛合金激光穿透焊的焊缝成形(Ⅱ)

Weld shaping for laser fully penetration welding titanium alloy (II)

在前文基础上进一步研究了钛合金激光穿透焊的热源作用模式及熔池流动特点对焊缝成形的影响。研究结果表明 ,钛合金激光穿透焊的焊缝成形是焊接过程中”两点一线”热源作用模式和熔池流动传热特点所决定的。焊接热输入和激光功率密度对”两点一线”热源作用模式及熔池流动传热特点具有重要的影响。随焊接热输入和激光功率密度的增大 ,金属蒸气和等离子体的热辐射以及熔池上部和熔池下部的流动传热作用增强 ,焊缝截面由钉形向近X形转变。根据点、线热源叠加原理获得了”两点一线”

Thermal effect of heat souce and fluid flow in weld pool for laser full penetration welding titanium alloy were investigated. The resules show that the laser fully penetrated weld shaping of titanium alloy depends on the thermal effect of “two points and one line” heat sources and the fluid flow in weld pool that is influenced intensively by heat input and la ser power density in welding. With increase of heat input and laser power density, the thermal effect of metal plasma and metal vapor as well as the fluid flow and the heat transfer in weld pool increase obviously, and the cross section of weld transforms from nail shape to near X shape. A model for the temperature distribution, which includes two point heat sources that lie on the top and bottom surface of the workpiece respectively amt one line heat source, is proposed.