Effects of pulsed and continuous Nd–YAG laser beam waves on welding of Inconel alloy
Effects of pulsed and continuous Nd–YAG laser beam waves on welding of Inconel alloy
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DOI：
10.1179/174329305x46709
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发表时间：
2005-09
影响因子：
3.3
通讯作者：
T. Kuo
中科院分区：
文献类型：
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作者：
T. Kuo
采用2.5kW高功率激光对3 mm厚的Inconel690钢板进行了堆焊和对接。焊接使用矩形激光脉冲进行，其峰基功率比WR从初始值10降至1，保持相同的平均功率为1.7kW。因此，焊接模式从脉冲波变为连续波。防喷器结果表明，在较低的移动速度和/或较高的WR值时，焊缝熔深增加。在对接焊接过程中，WR从1增加到10，焊缝的胞状组织基本保持不变，但大气孔形成率从7.1%下降到0.6%。在WR值较低时，主要在根部区域识别大孔隙度。然而，随着WR的增加，相关的周期性高功率增加了熔池的搅拌，并可能导致气泡向上漂浮。因此，在WR值较高时，大气孔区域在整个焊缝中随机分布。虽然在任何一个焊缝中都没有明显的微裂纹，但每个焊缝都显示出轻微的微气孔。这种微孔率随着WR的增加而减小。结果表明，在Inconel690激光焊接中，采用峰值功率合适的脉冲激光可以达到焊缝力学性能和表面粗糙度之间的折衷。
In the present work a 2·5 kW high power Nd–YAG laser is used in the bead on plate (BOP) and butt welding of Inconel 690 plates of thickness 3 mm. Welding is performed using a rectangular laser pulse, for which the peak to base power ratio Wr is reduced from an initial value of 10 to a value of 1, maintaining an identical mean power of 1·7 kW. Therefore, the welding mode changes from a pulsed wave to a continuous wave. The BOP results indicate that the depth of the weld penetration increases at a lower travel speed and/or a higher value of Wr. In the butt welding process, as Wr is increased from 1 to 10, the cellular microstructure of the weld remains relatively unchanged, but the macroporosity formation ratio decreases from 7·1% to 0·6%. At low values of Wr, macroporosity is identified primarily in the root region. However, as Wr increases, the associated periodic high power increases the agitation of the molten pool and probably causes bubbles to float upwards. Consequently, at higher values of Wr, the regions of macroporosity are distributed randomly throughout the weld. Although microcracks are not apparent within any of the welds, each weld exhibits slight microporosity. This microporosity decreases as Wr increases. The present results confirm that a pulsed laser beam with an appropriate peak power can be used to achieve a compromise between the mechanical properties and surface roughness of the weld for Inconel 690 in Nd–YAG laser welding.