中性盐溶液辅助激光加工试验研究

针对激光加工存在再铸层、热影响区(HAZ)的致命缺陷,提出了中性盐溶液辅助激光加工(SALM)方法,利用中性盐溶液对材料的热化学作用和持续冷却作用在线去除再铸层和热影响区.基于激光在中性盐溶液下衰减的特性研制了试验系统,并对0.5 mm厚的不锈钢片进行了打孔试验,通过对该方法与空气中激光打孔(LBM)加工效果的比较,证实了中性盐溶液辅助激光加工的可行性.试验结果表明,随着盐溶液浓度及流速的增加,中性盐溶液辅助激光加工对于再铸层和热影响区的去除效果越明显;流速5 m/s,质量分数为20%的NaCl溶液辅助激光加工可实现再铸层的厚度减少80%,热影响区的范围缩小90%以上.

Experimental Study of Neutral Salt Solution Assisted Laser Machining

In order to solve the Achilles' heel of recast layer and heat affected zone produced during laser machining,a new processing of neutral salt solution assisted laser machining(SALM) is put forward,which can remove recast layer and heat affected zone(HAZ) on-line by using the effect of salt solution on the thermal chemical reaction and continuing cooling effect of materials.Based on the properties of laser attenuation in neutral salt solution,the experimental system was designed,and a drilling experiment on a 0.5mm thickness stainless steel sheet was done.It is confirmed that the principle of SALM is right and the processing is feasible by comparing the results of the SALM with laser beam machining(LBM) in air.The drilling experiment results show that the quality of removing recast layer and HAZ are better with the increase of solution concentration and flow velocity,and the thickness of recast layer is reduced by 80%,the dimension of HAZ is reduced by more than 90% during SALM in NaCl solution with concentration of 20% and flow velocity of 5 m/s.