挤压铸造工艺参数的设计准则  

Design Rules of Some Characteristic Parameters in Squeeze Casting(Molten Metal Die Forging)Process

作　　者：邢书明[1] 鲍培玮[1] 于佰水 李春奎 

机构地区：[1]北京交通大学机械与电子控制工程学院 [2]吉林冠通汽车配件有限公司

出　　处：《特种铸造及有色合金》2015年第6期576-579,共4页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51275031);吉林省重点攻关计划资助项目(2013020635GX)

摘　　要：通过对挤压铸造过程凝固和流变行为的分析,提出了密实比压、保压时间、浇注量以及挤压力4个关键工艺参数的设计准则和相应的设计计算公式。密实比压必须大于挤压合金熔点附近的流变应力与沿补缩通道流变的压力降之和,或者挤压力的有效补缩距离大于热节位置与加压位置的距离,或者热节位置(最后凝固部位)的比压始终大于零,否则就会出现收缩缺陷;保压时间约等于最后凝固位置的凝固时间与开始加压时间之和,否则会出现收缩缺陷或裂纹缺陷;浇注量必须大于考虑了金属熔体的体收缩和工艺余料的临界浇注量,同时还要小于压室的有效容积,否则会出现不能完整成形的缺陷。挤压力应大于密实压力、压头运动过程的阻力以及凝固壳发生切变流动的剪切抗力或发生拉伸流动的拉伸抗力之和,否则可能出现不能成形或存在收缩缺陷。这些准则在钢铁材料和铝合金的挤压铸造实践中被证明有效可行。Through an analysis of the solidification and rheologic behavior, some design rules and their mathematic expression were presented about some key parameters , such as compacting pressure, hold- ing pressure time, pouring volume and pressing force, in the squeeze casting process, or molten metal die forging process（MMDF for short）. The compacting pressure in the process must be more than the sum of the resistant flowing stress of the alloy and the resistant stress along the feeding channels, or the feeding range should be larger than the distant from the pressing palace to the hot spot of the workpiece; or the available pressure at the final solidification position is more than zero in the whole pressing peri- od, if not, shrinkage defects could be observed. The holding pressure time should be larger than the so- lidification time in the final solidification position, if not, shrinkage cavity or crack easily occurs. The pouring volume should be larger than the sum volume of the workpiece and the technique remainder, and smaller than the valid volume of the pressing chamber, if not, misrun can be observed. The pressing force has to be large enough to make the solidificated alloy flow to feed the shrinkage, to make the work- piece compact and overcome the resistant force from the friction between the punch and the die, if not, misrun or shrinkage cavity could occur. The validity of these rules has been proved by many facts of alu- minum alloy and iron and steel.

关 键 词：挤压铸造 工艺参数 设计规范 

分 类 号：TG249.2[金属学及工艺—铸造]