异步轧制硅钢薄带的固体渗硅

Solid powder siliconizing of silicon steel shin strip produced by asymmetric rolling

为了探索利用轧制技术在板材表面获得纳米结构，并以此降低渗硅温度和卤化物质量分数，取硅质量分数3.0%硅钢和硅质量分数0.5%硅钢依次进行异步轧制和固体渗硅，对组织、物相和成分进行测试分析。结果表明，经过大压下量的异步轧制后，2种薄带的表面均形成了纳米晶，晶粒尺寸分别为50和70～120 nm。硅粉＋质量分数5%卤化物在500℃以上即可实现固体渗硅，原始板材中较高的硅质量分数有助于降低渗硅的初始温度。提高渗硅温度及在较高的温度下延长保温时间均可增加渗硅层厚度，而卤化物质量分数的影响不大。随着温度和卤化物质量分数的增加，渗硅层物相依次为：Fe3Si→FeSi＋Fe3Si→FeSi。

In order to investigate the possibility to reduce the temperature and the halide content in a siliconizing process through the formation of nanostructure on the surface layer of steel strip,3.0%and 0.5%silicon steel samples were se-lected to be treated by means of asymmetric rolling and solid powder siliconizing treatment,the microstructural evolu-tion,the phase transformation and the compositions were examined using different techniques. Experimental results show that,nanocrystallines form on the top surface layer of both kinds of samples after the asymmetric rolling with a large reduction,the grain sizes are 50 nm and 700-120 nm,respectively. After the siliconizing at 500℃in the mixture of Si powder and 5%halide,compound layers can be obtained for both of the asymetric rolled samples,a higher Si con-tent in original sample is helpful for the reduction of the initial siliconizing temperature. The thickness of the compound layer is observed to increase significantly with the increment of the siliconizing temperature and the duration at higher tem-perature,however remains unchanged with the increment of halide content. With the increment of siliconizing temperature and halide content,phase transformations in the compound layer are detected as follows：Fe3Si→FeSi＋Fe3Si→FeSi.