High-quality bearing steel with the billet caster process
PAN Yi-fang1，LI Shu-qing1，HOU Kui1，ZHAO Xin-kai2，ZHANG Jiong-ming2，WANG Bo2
1. Technology Center of Tianjin Tiangang Group Co., Ltd., Tianjin 300301, China 2. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
Abstract：Compared to the EAF and bloom process, converter and billet process for smelting bearing steel has the advantage of low production cost. Based on the actual production in Tianjin Iron and Steel Company, the research on the key technique during the process "hot metal pre-desulfurization-converter smelting-LF refining-VD refining-billet casting" has been undertaken. By taking samples systematically and analyzing the inclusion of the samples during the process, the following conclusions were obtained. The wT［O］ decreased with the increase of basicity of slag (R). The optimum basicity of slag ranged between 7.0 and 9.0. In the early stage of LF refining, the Al2O3 was high in the inclusion; during the process of refining, the composition of inclusion developed to Al2O3-MgO and CaO-Al2O3-MgO; the VD treatment promoted the steel-slag reaction to the balanced direction and the content of CaO in inclusion increased. In the process of billet casting, the method of two-stage electromagnetic stirring, lower casting velocity and smaller ratio of water spray obtained lower degree of carbon segregation.
2015, Vol. 25 
