The relationship between a sample’s temperature and the plasma spectrum is of great significance for the quality of smelting. In this work, the main purpose was to study the temperature variation effect of the plasma spectrum in a steel sample for on line analysis using LIBS. Both the spectral intensity of ions and atoms increased as the temperature increased. When the temperature rises to the melting points (1432 °C), the spectral intensity tends to stabilize. To analyze the reasons for the enhancement of spectral lines, the plasma temperature was calculated by the Boltzmann plane method; and the plasma temperature at 1432 °C and 20 °C was 14,709 K and 14,227 K, respectively. The results showed that the sample temperature had little effect on the plasma temperature. Compared with 20 °C, the correlation coefficient of Cr II 205.56 nm, Mn II 293.31 nm, Si I 288.16 nm and C I 193.09 nm at 1432 °C increased from 0.9577, 0.9516, 0.9681, and 0.9739 to 0.9832, 0.9947, 0.9925, and 0.9912, respectively. The RMSEP of the four elements at 1432 °C also increased from 1.24%, 0.49%, 0.85%, and 0.41% to 0.27%, 0.09%, 0.16%, and 0.08%, respectively. The LOD of the four elements reached 128 ppm, 135 ppm, 78 ppm, and 65 ppm at 1432 °C, respectively. It indicated that on-line monitoring of molten steel can be realized by controlling the temperature in the field smelting process.

样品温度与等离子体光谱的关系对熔炼质量具有重要意义。在这项工作中，主要目的是研究钢样品中等离子体光谱的温度变化效应，以便使用 LIBS 进行在线分析。离子和原子的光谱强度都随着温度的升高而增加。当温度升高到熔点 (1432 °C) 时，光谱强度趋于稳定。为分析谱线增强的原因，采用玻尔兹曼平面法计算等离子体温度；1432 °C 和 20 °C 时的等离子体温度分别为 14,709 K 和 14,227 K。结果表明，样品温度对等离子体温度影响不大。与20℃相比，Cr II 205.56 nm，Mn II 293的相关系数。31 nm、Si I 288.16 nm 和 CI 193.09 nm 在 1432 °C 下分别从 0.9577、0.9516、0.9681 和 0.9739 增加到 0.9832、0.9947、0.9925 和 0.9。四种元素在 1432 °C 时的 RMSEP 也分别从 1.24%、0.49%、0.85% 和 0.41% 增加到 0.27%、0.09%、0.16% 和 0.08%。四种元素的 LOD 在 1432 °C 下分别达到 128 ppm、135 ppm、78 ppm 和 65 ppm。表明在现场冶炼过程中控制温度可以实现钢水的在线监测。四种元素的 LOD 在 1432 °C 下分别达到 128 ppm、135 ppm、78 ppm 和 65 ppm。表明在现场冶炼过程中控制温度可以实现钢水的在线监测。四种元素的 LOD 在 1432 °C 下分别达到 128 ppm、135 ppm、78 ppm 和 65 ppm。表明在现场冶炼过程中控制温度可以实现钢水的在线监测。