【摘要】 激光金属沉积技术作为激光增材制造技术的重要发展方向，已在航空领域得到广泛应用。在激光金属沉积加工工艺中，熔池温度的模拟与监测研究对金属成形质量的分析具有关键作用。通过精确控制熔池温度，可有效地提高航空部件的成形精度和材料性能，从而满足航空工业对高强度、轻质、高性能部件的要求。本文以316 L不锈钢为研究对象，通过仿真与试验相结合的手段深入研究了激光金属沉积316 L不锈钢熔池温度场。利用有限元仿真手段建立了激光金属沉积316 L不锈钢块体结构的三维有限元模型，揭示了316 L不锈钢在不同加工参数（激光功率、扫描速度等）下激光金属熔融沉积过程中的热行为。仿真结果表明，在块体打印过程中，打印的每一层首道温度往往相较于其他熔覆道更高；在激光金属沉积过程中，熔池末端出现了一个“彗星状”的尾部，表明熔池前部的温度梯度较大。采用自主研制的激光金属沉积设备，并利用比色高温计对熔池温度进行在线测量，激光功率为1400 W，扫描速度为330 mm/min时熔池测量温度结果与仿真结果吻合。仿真块体打印相比于试验单臂墙体打印，两边散热条件不一致，导致熔池产生成形微观组织左右差异，通过样品金相结果验证了生长方向向空气侧倾斜，而非竖直向上。为研究激光金属沉积过程中316 L不锈钢熔池温度变化规律提供了参考。更多还原

【Abstract】 Laser metal deposition(LMD), as an important development direction in laser additive manufacturing technology, has been widely applied in the aerospace field. In the LMD process, the simulation and monitoring of the melt pool temperature play a crucial role in the analysis of metal forming quality. By precisely controlling the melt pool temperature, the forming accuracy and material properties of aerospace components can be effectively improved, thus meeting the aerospace industry’s demand for high-strength, lightweight, and high-performance components. This paper focuses on 316 L stainless steel, combining simulation and experimental methods to investigate the melt pool temperature field during laser metal deposition of 316 L stainless steel. A three-dimensional finite element model of the 316 L stainless steel bulk structure in the LMD process was established using finite element simulation methods. The thermal behavior of 316 L stainless steel during the laser metal melting deposition process under different processing parameters(such as laser power, scanning speed, etc.) was revealed. The simulation results show that during the bulk printing process, the temperature of the first layer printed is usually higher than that of the other cladding layers. In the LMD process, a “comet-shaped” tail appears at the end of the melt pool, indicating a significant temperature gradient at the front of the melt pool. Using self-developed LMD equipment and an optical pyrometer for online melt pool temperature measurement, the measured melt pool temperature at a laser power of 1400 W and a scanning speed of 330 mm/min was compared with the simulation results, which showed good agreement. Finally, due to the different heat dissipation conditions between the simulation bulk printing and the experimental single-arm wall printing, the melt pool caused lateral differences in the microstructure of the formed part. Metallographic results confirmed that the growth direction tilted towards the air rather than growing vertically upwards along the substrate. This study provides a reference for the investigation of the melt pool temperature during the laser metal deposition process of 316 L stainless steel.更多还原