铸钢冒口最小安全高度及富余钢液体积比的计算

Calculating Methods of Cast Steel Risers' Minimum Safety Height and Volume Ratio of Surplus Molten Steel

通过建立冒口铸件凝固数学模型,利用凝固时间与模数对应关系的Chvorinov法则,推导出了冒口最小安全高度、冒口富余钢液体积比计算公式。在用模数法或其他方法设计铸钢冒口时,可用其计算冒口最小安全高度和冒口富余钢液体积比作为校核。实践表明,冒口最小安全高度应大于铸件壁厚或热节圆的25%、冒口富余钢液体积比大于15%,冒口缩孔不会深入铸件内部。在此前提下,冒口补缩效率可不受限制,铸造工艺出品率显著提高。

The calculating formulas about the risers＇ minimum safety height and the volume ratio of the surplus molten steel were derived by establishing the solidification mathematical model of a riser-casting system and using the Chvorinov law involving the relationship between freezing time of liquid steel and its geometric modules. When the cast steel risers were designed by modules or other methods, the parameters derived from the above formulas could be used as safety check. The practice indicated that the shrinkages in risers could not embed in the castings while the minimum safety height was 25% thicker than the wall thickness or heat node circle diameter of castings and the risers＇ volume ratio of the surplus molten steel was higher than 15%. Based on this, the riser efficiency would be not limited and the casting yield outstandingly raised.