K418与42CrMo异种金属的激光穿透焊接

Dissimilar Metal of K418 and 42CrMo Full Penetration Laser Welding

实验研究了连续波Nd∶YAG激光焊接速度、侧吹保护气流量和离焦量等参量对激光穿透焊接K418和42CrMo焊缝成形的影响。结果表明,K418与42CrMo激光穿透焊接有X形和T形两种典型的焊缝形貌,且焊缝形貌是不对称的。随着焊接速度的提高,焊接线能量降低,焊缝尺寸变小,且焊缝上部尺寸变化比下部尺寸变化慢,焊缝形貌由X形过渡到T形。当离焦量在瑞利长度范围内时,焊缝正面宽度变化很小;当离焦量超出瑞利长度范围时,在足够高的激光功率密度下,焊缝正面宽度快速增加。在激光功率为3 kW,侧吹保护气角度为35°条件下,通过优化焊接速度、侧吹保护气流量和离焦量等参量可以得到最佳焊缝质量。

The influences of laser welding velocity, flow rate of side-blow shielding gas, defocusing distance and other parameters on the full penetration laser weld seam of K418 and 42CrMo were experimentally investigated using continuous wave Nd： YAG laser. Results show that the asymmetric cross-sections of weld seams exhibit X shape or T shape. With increasing welding velocity, the linear heat input and dimension of weld seam decrease, and the shape of it changes from X shape to T shape. Meanwhile, the rate of change in dimension of weld bottom region is larger than that of weld top region. The change of the top surface width of the weld seam is small under the condition that defocusing distance changes within the range of Rayleigh length; the top surface widths of the weld seam increase quickly under the condition that defocusing distance changes out of the range of Rayleigh length with enough density of laser power. The high-quality of weld seam with constant 3 kW laser power and 35° angle of side-blow shielding gas can be obtained by optimizing welding velocity, flow rate of shielding gas, defocusing distance and other parameters.