久爱伊人,亚洲天堂aaa,欧美三级电影网站,国内一级黄色毛片,aaa毛片在线观看,青青福利,在线中文天堂

　　The removal of drainage sand is a big technology problem for metallurgy industry and a limit on production of clean steel. During the production of steel, since the sand particals are very small and the duration staying in the tundish is very short, the drainage sand will be flushed into the hot metal and get the hot metal polluted.

　　The research team of steel-making plant made the drainage sand blowing equipmen, overcomeing the high temperature, small operating space and  short operation time, and finally find the method to remove the drainage sand.

　　At present, they had tested this technology during the production of tyre cord steel, bearing steel and spring steel, and the performance is remarkable.