为研究激光熔凝中熔池的光谱辐射特性, 采用光栅光谱检测技术, 检测了激光定点辐照和不同速度下45钢熔池光谱, 得到不同功率、不同速度的光谱分布。结果表明: 功率500 W激光定点辐照下, 在波长532 nm处熔池光谱相对强度最高为1 936, 激光继续辐照时光谱相对强度不再增加, 达到准稳态状态; 激光功率1 000 W时, 532 nm波长处熔池光谱相对强度最高3 010, 有部分光谱曲线饱和。激光熔凝熔池光谱波动与熔凝表面质量存在一定的关系, 激光功率950 W, 扫描速度1 mm/s时, 熔池光谱相对强度波动较大, 在565 nm处光谱线波动500, 熔凝质量较差; 扫描速度4 mm/s时, 可得到较平整的熔凝层, 光谱谱线最大波动在220～310。对定点辐照下熔池光谱中的发射谱线标定表明, 线光谱主要由FeI辐射。该检测结果可用于激光熔凝工艺优化, 实现激光熔凝的在线监控和反馈控制。

Based on grating spectrum detection technology, spectrum of molten pool of 45 steel was measured to study the spectral radiation characteristics. Laser targeted irradiation and different scanning speeds were carried out; Spectral distribution at different power and different speed was measured. It is shown at wavelength 532 nm max relative intensity of spectrum of molten pool was 1 936 when laser power was 500 W and laser irradiation targeted. It achieved quasi-steady and Spectrum relative intensity was not increased. Max relative intensity of spectrum of molten pool was 3 010 at wavelength 532 nm when laser power was 1 000 W, and part of the spectrum curve was saturated. There was a certain relationship between the quality of laser melting layers and spectrum fluctuation of molten pool. Laser power 950 W and scanning speed 1 mm/s, spectrum fluctuation of molten pool was bigger; the spectral relative intensity fluctuated value was 500 at wavelength 565 nm. When laser scanning speed was 4mm/s, laser solidified layer was flat. Calibration of molten pool spectrum shows that most of line spectrum was Fe I radiation. Laser melting parameters were optimized by the measurement results, and monitoring on line and closed loop control could be achieved.