铸钢冒口最小安全度及富余钢液体积比计算方法研究.doc

铸钢冒口最小安全高度及富余钢液体积比计算方法研究 Study on Calculating Methods of Minimum Sound Height and Volume Ratio of Surplus Melt Steel in Risers for Steel Castings 湖北工业大学 黄晋 张友寿 夏露 李四年 Hubei University of Technology Huangjin, Zhang Youshou, Xia Lu, Li Sinian 摘要：用传统的铸钢冒口设计方法，不能计算冒口最小安全高度和冒口中富余钢液体积比。为了保证铸件不产生缩孔，只能限制冒口补缩效率在一个的很低水平，冒口钢液利用率不高。本研究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。在用模数法或其它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。 关键词： 最小安全高度 富余钢液体积比 冒口设计新方法 Abstract The traditional design methods of risers for steel castings can not be employed for calculating the minimum sound height and the volume ratio of surplus liquid steel in risers. In order to guarantee steel castings do not produce shrinkage voids, the feeding efficiency of risers only can be limited in a very low level, the utilization ratio of molten metal in risers is not high. The calculating formulas about the minimum sound height and the volume ratio of the surplus melt steel of risers were derived through establishing the solidification mathematical model of a riser-casting system and by making use of the Chvorinov law involved corresponding relationship between freezing time of liquid steel and its geometric modules. When the risers for steel castings were designed by modules or other methods, as an inspection of safety，the minimum sound height and the volume ratio of surplus liquid steel of these risers could be computed with above formulas. The practice indicated that the shrink holes in risers could not go deep into the castings while the minimum sound height was bigger than 25% of the wall thickness or heat node circle diameter of castings, the volume ratio of the surplus melt steel of risers was bigger than 15%. Based on this, the feeding efficiency of risers would be not limited and the casting yield outstandingly raised. Key words: the minimum sound height; the volume ratio of surplus melt s