搭建了一套基于激光诱导击穿光谱技术的钢液成分直接测量实验系统,针对钢液表面被空气氧化的问题进行了实验,评估了氧化层对测量结果的影响.在此基础上,利用氩气作为保护气,对比分析了不同氩气流量下,钢液内各元素谱线强度和测量稳定性的变化趋势.结果表明：钢液氧化会令大部分合金元素在表面富集,从而使相关谱线的相对强度增大,因此不宜在大气环境下进行钢液成分的直接测量;而选择合适流量的氩气作为保护气可以实现稳定的钢液成分直接测量.

An experiment system aimed to direct analyze liquid steel based on Laser-Induced Breakdown Spectroscopy has been built. A laboratory-scale induction furnace of 1 kg capacity is used to melt steel sample. The process of oxidization in the surface of liquid steel under atmospheric conditions is tested, and its influence to the results of analysis is discussed. Ar is used as inert gas to exclude the ambient air from the surface of liquid steel, and the changes of the intensity and RSD of elementals emission lines with the flow rate of Ar are detailed. The results of analysis show that the relative intensities of alloying elements line increase with the formation of oxidization in the surface of liquid steel, because the formation of oxide mixtures by most of alloying elements lead to a higher fractional concentration of these elementals on the sample surface. The result of direct analysis of liquid steel can be improved using Ar as inert gas with an appropriate flow rate.