激光功率对316L不锈钢熔覆层组织及性能的影响

为了解决316L不锈钢激光熔覆层成形差、耐腐蚀性低的问题，采用显微组织观察、硬度实验、常温冲击及电化学测试等试验方法，对不同激光功率下熔覆单层及多层熔覆层的成形、组织及性能进行检测和分析。结果表明，随着激光功率的增大，熔覆层高度呈现先增加后减小的变化趋势，熔覆层内部析出相的含量以及稀释率则呈现上升趋势；激光功率过小易引起熔覆层开裂，过大则会引起熔覆层晶粒异常长大；随着激光功率的增加，熔覆层硬度呈增大趋势，当激光功率达到450 W时，熔覆层与基材结合界面处硬度值达到最大，为475 HV;而熔覆层的冲击性能和耐腐蚀性能则随着激光功率的增大呈现下降趋势，当激光功率为300 W时，其冲击韧性最大为92 J,且熔覆层具有最优的耐腐蚀性能，腐蚀电位E_corr最高为-0.3 V,且腐蚀电流密度I_corr最小为0.165 A/cm²;因此，当熔覆速率为3 mm/s、送粉速率为14 g/min、搭接率为50%时，采用300 W激光功率制备的熔覆层可得到优异的冲击和耐腐蚀性能。研究结果可为316L激光熔覆层工艺调控及性能改善提供参考。

Effect of laser power on the microstructure and properties of 316L stainless steel cladding layer

To solve the problems of poor forming and low corrosion resistance of 316L stainless steel laser cladding layer, the forming, microstructure and properties of single-layer and multi-layer samples prepared at different laser powers were detected and analyzed by microstructure observation, hardness testing, impact testing and electrochemical testing. The results show that the height of the laser cladding layer initially increases and subsequently decreases with the increase of laser power. The content of precipitates and the dilutionrate increase with the increase of laser power. Cracks occur in the laser cladding layer under the condition of low laser power, and it can cause the grains to grow abnormally under the condition of high laser power. Meanwhile, the hardness value of the laser cladding layer increases with the increase of laser power. The hardness value at the interface reach a maximum value of 475 HV when the laser power is 450 W. However, the impact toughness and corrosion resistance of the laser cladding layer decreases as the laser power increases. The maximum impact toughness is 92 J of the laser cladding layer prepared with the laser power of 300 W. Meanwhile, the laser cladding layer prepared with the laser power of 300 W has the best corrosion resistance, with its highest corrosion potential (Ecorr) of -03 V and lowest corrosion current density (Icorr) of 0165 A/cm2, respectively. Therefore, the laser cladding layer prepared at 300 W laser power can obtain excellent impact and corrosion resistance when the laser cladding speed is 3 mm/s, the powder feeding rate is 14 g/min, and the overlap rate is 50%. The research results can provide a reference for the parameter control and performance improvement of laser cladding 316L layer.