存在旋转圆跳动的轧辊表面的送丝激光熔覆工艺研究

Study on wire-fed laser cladding of the roller with circular runout

为解决轧辊旋转时产生的圆跳动影响送丝激光熔覆轧辊修复的问题,对轧辊旋转圆跳动对于丝材尖端与轧辊面位置及激光熔覆过程的影响规律进行理论分析,并针对激光功率和光斑直径对存在圆跳动的轧辊激光熔覆修复工艺的影响进行试验研究。研究结果表明:在熔覆过程中,由于圆跳动的影响,前沿送丝成形的熔覆道高度过低,后沿送丝成形的熔覆道易出现大量毛刺,但中间送丝成形的熔覆道表面形貌相对较好;在小光斑、低功率工艺状况下,中间送丝成形的熔覆道也会出现孔隙以及毛刺,增加激光功率和光斑直径可以减少此现象。在圆跳动误差不大于0.6 mm情况下,当激光功率P为2 400 W、指示红光直径为6.5 mm时,几乎不会出现缺陷。采用小搭接率进行多道搭接试验时,圆跳动会影响第1道熔覆道的实际成形位置,搭接率为40%时成形的熔覆道受影响不明显。

To solve the problem that circular runout affects repair of rollers with wire-fed laser cladding,theoretical analysis of effects of runout on location variation between the cladding head and the workpiece surface as well as the laser cladding process was carried out,and effects of laser power and spot diameter on repair of the circularly-runout roller were studied experimentally.The results show that the low height clad channel exists in laser cladding with wire pointing at leading edge of the melting pool,a large number of burrs and undercuts appear in laser cladding with wire pointing at the trailing edge of the melting pool,but the surface morphology of the clad bead is relatively good in laser cladding with wire pointing at the center of the melting pool.Under condition of laser spot with small diameter and low power,pores and burrs will also occur in laser cladding with wire pointing at the center of the melting pool, while increasing laser power and laser spot diameter can reduce this phenomenonin laser cladding. When the circular runout error is not larger than 0.6 mm, at laser power of 2 400 W and diameterof 6.5 mm of red guiding light spot on the workpiece surface, defects almost don't appear in wire-fed lasercladding. When the small overlap rate is applied during multilayered clad tests, the circular runout will affect theactual forming position of the first bead. However, this impact is not evident when the overlap rate is 40%.