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凡中碳钢、合金结构钢、工具钢、滚珠轴承钢和非奥氏体不锈钢等大中型钢锭脱模后,除热送外都要经过缓冷,否则会产生纵裂而报废。目前国内常用的缓冷方法有模冷法、坑冷法、模冷加坑冷法和埋砂缓冷法。其中,模冷法在北方用得较多、效果也好,但在南方因气候湿度大、钢中含氢量较高,从采用的几个厂情况看,钢锭纵裂现象较多;坑冷法因一炉一坑,占地面积大,钢锭冷却规律往往受到操作的影响而不能保证,另外当坑内只缓冷少量钢锭时,坑壁大量吸热,加快了钢锭表面的冷却,结果常导致钢锭纵裂的产生;模冷加坑冷方法的效果也不理想,国内各厂因钢锭纵裂的报废率一般高达5％左右,损失是可观的;有些工厂,如上海汽轮机厂铸钢车间为消除钢锭的纵裂废品,不得不采用落后的坪砂工艺,这样,虽然基
Where the medium carbon steel, alloy steel, tool steel, ball bearing steel and non-austenitic stainless steel and other large and medium-sized steel strip after demoulding, except to send through the slow cooling, otherwise it will have vertical split and scrapped. At present, the commonly used method of slow cooling are mold cooling method, pit cooling method, mold cooling plus pit cooling method and sand burning slow cooling method. Among them, the mold cooling method used more in the north, the effect is good, but in the south due to the climate of humidity, high hydrogen content in steel, the situation from several plants used, ingot longitudinal cracking phenomenon more; cold pit Law for a furnace a pit, covers an area of large, ingot cooling rules are often affected by the operation can not be guaranteed, the other when the pit is slowly cooling a small amount of steel ingot, pit wall large endothermic, accelerating the ingot surface cooling, the result often leads to The effect of mold cooling plus pit cooling method is not satisfactory. The scrap rate of domestic factories due to longitudinal cracking of ingot is generally as high as about 5%, and the loss is considerable. In some factories, such as Shanghai Steam Turbine Works’ Elimination of longitudinal ingot waste steel scrap, had to use lagging Ping-sand process, so, although based