激光诱导击穿光谱法对钢铁偏析样品的分析

经典判断钢铁样品是否存在偏析带方法有金相显微及硫印方法，其缺点在于分析速度慢，且无法提供元素的含量分布信息。文中在最佳实验条件下，采用激光诱导击穿光谱(LIBS)，在空间横向分辨率约为100 μm左右对两块钢铁中低合金板坯及均匀样品扫描分析，在建立校准曲线的基础上，将元素强度二维分布转化为含量二维分布。研究表明，编号为86#样品C，Si，Mn，P，S及Cu等元素存在明显的偏析，编号为174#样品C，Si，P，Ti等元素存在明显的偏析，并对偏析带的宽度进行估算，其偏析带的位置及宽度与金相显微分析方法相吻合。对均匀样品扫描分析，C，Si，Mn，P，S等元素均匀分布，不存在偏析带，通过元素强度或含量二维分布图可间接反映样品的均匀性。与传统的金相分析方法相比较，LIBS不仅可快速准确体现样品偏析带位置及宽度，而且还可同时提供元素含量分布(如C，Si，Mn，P，S等元素)等方面的信息。此方法可用于快速对钢铁样品是否存在偏析带及其宽度进行表怔，从而为钢铁冶炼工艺的改进提供理论依据。

Segregation Bands Analysis of Steel Sample Using Laser-Induced Breakdown Spectroscopy

In the present paper, under optimum experimental condition, two middle-low alloy slab and homogeneous samples were analyzed under the condition of spatial resolution about 100 μm by scanning mode. Element 2D intensity distribution can be converted into 2D concentration distribution via establishing calibration curve. The results showed that there is a central segregation for C, Si, Mn, P, S and Cu for 86# slab sample, and C, Si, P and Ti for 174# slab sample, the width of segregation band was estimated, and it agrees well with metallographic analysis. Homogeneous sample was analyzed by scanning mode, the result showed that C, Si, Mn, P, S and so on are well distributed, and there is no segregation band existing. 2D distribution of element intensity or concentration can be used to indirectly reflect sample’s homogeneity. Compared with traditional metallographic analysis, LIBS can not only show central segregation bands position and width, but also provide 2D concentration distribution for C, Si, Mn, P, S etc in detail. This method can be used to characterize segregation band position and its width rapidly, and provide theoretical guidance for improving metallurgical process.