激光功率对铝制换热器钎焊接头性能及微观组织的影响

Effect of Laser Power on Microstructure and Properties of Brazed Joint of Aluminum Heat Exchanger

为了改善焊接生产环境,减小能源消耗,提高生产效率,利用小功率光纤激光器对铝制空调换热器进行激光钎焊试验研究,分析了激光功率对钎焊接头性能及微观组织的影响。结果表明:钎焊接头成型良好,焊缝熔合线长度合格;液态钎料的润湿铺展性能随着激光功率增加而显著改善;接头通过基本耐压性能试验及气密性检验的合格率均随激光功率增大而增加;钎焊接头由焊缝区、界面区及母材组成,焊缝主要由α(A1)固溶体及针状或树枝状共晶Si组成,界面区为单相α(Al)固溶体;随着激光功率增大,焊缝晶粒略有长大。

In order to improve the welding environment, reduce the energy consumption, enhance the productivity, aluminum air-condition heat exchanger was brazed by using small power laser to braze the aluminum air-condition heat exchanger, then, the effects of laser power on the microstructure and properties of brazed joints were studied. The results indicate that the brazed joints have good shape, the length of weld fusion line is qualified. The properties of wetting and spreadability improve with the increase of laser power. The pass percent of brazed joints pressure test and tightness test raises with laser power increasing. The brazed joint is composed of brazing seam, interracial area and base metal. Aluminum solid solution and acicular or dendritic eutectic Si exist in brazing seam. The interfacial area is single aluminum solid solution phase. With laser power increasing, the grain size of weld seam grows up slightly.