有些零件(如合金鋼零件,鑄鍛件,焊件等)在热处理过程中要求緩慢冷却;而一般是在零件上复盖一层黄砂,来代替零件的随爐冷却。可是这种方法有些缺点,首先是劳动强度高;放砂时灰尘飞揚,影响工人的健康和仪表的維修;占地面积大;砂层厚度不均匀,容易影响冷却效果。我厂热处理車間采用石棉制成的罩子來代替盖砂,完全克服了上述的缺 Some parts (such as alloy steel parts, castings and forgings, weldments, etc.) require slow cooling in the heat treatment process; and usually the parts covered with a layer of yellow sand, instead of parts of the furnace cooling. However, this method has some shortcomings, first of all, labor-intensive; dust flying sand, affecting the health of workers and instrument maintenance; large area; sand thickness uneven, easy to affect the cooling effect. I plant heat treatment plant made of asbestos cover instead of cover sand, completely overcome the above lack