Hot top is a kind of casting equipment.It is made of cast iron shell and refractory lining. Its role is to make the cap mouth part of the liquid steel can longer stay liquid, so that the molten steel in the solidification process of steel ingot ingot body volume shrinkage of supplement unceasingly, makes the final shrinkage cavity in cap line above, ensure the ingot body tissue density is not a shrinkage and osteoporosis, to reduce the ingot defects and the purpose of cutting head loss. Hot top has the reasonable structure parameters: mo capacity ratio, cross section shape, shoulder width, taper and corner radius etc.To guarantee the effective thermal insulation cap feeding effect. (1) hat capacity ratio.Insulation cap inner cavity volume and the ratio of the ingot total volume.Insulation cap volume to ensure that accommodate enough not condensate liquid steel to supplement the ingot solidification shrinkage of the ontology.Insulation cap lining the better heat insulation properties, hat, let the less than you can.In general, the clay brick lining insulation cap cap ratio is 16% ~ 20%, 12% ~ 16% when using coal cinder brick lining;With insulating board line is 10% ~ 10%.Small ingot and high quality requirements or shrinkage of large steel cap, vice take lower limit. (2) the section shape and shoulder width.Insulation cap inner cavity shape usually are truncated.Ingot mould fluently side length and thermal insulation cap within inner side according to the difference between the insulation cap shoulder width.General shoulder breadth of 20 ~ 50 mm, large steel ingot from upper limit. (3) the taper.To reduce heat loss on the surface of the liquid steel, reducing consumption of metal and facilitate his cap, insulation cap taper generally in 10% ~ 15%. (4) the corner radius.Increase the corner radius of insulation cap, which is beneficial to reduce heat loss, increase the feeding effect.The insulation cap upper Angle is larger, the lower is small, gradual transition ingot mould in the shape of the mouth.We designed cast clay brick lining insulation cap, it can be used multiple times and smooth when you put on, the surface after each use with refractory mortar on baking, drying and heat.And insulating board lining can only be a one-time use, usually after casting type car hanging nail or build by laying bricks or stones insulation board.Insulation board should be dry, shape rules should be complete.