理论和实践证明,灰铁和球铁在冷却和凝固过程中,既有液态收缩、凝固收缩,又有石墨析出产生的膨胀,即具有“胀缩相抵”的自补缩能力”。以往,对于厚大断面灰铁件,工艺设计往往过多注重冒口的补缩作用,将大冒口设置在铸件最后凝固的部位,而忽视了大冒口对铸件产生的热干扰作用,使铸件厚大断面的凝固时 Theory and practice have proved that both gray iron and ductile iron have both “shrinkage and shrinkage” self-shrinkage capacity in the process of cooling and solidification, including liquid shrinkage, solidification shrinkage, and swelling caused by precipitation of graphite. "In the past, Thick section of gray iron pieces, process design tend to pay too much attention to the role of feeder riser will be set in the final riser solidified parts of the casting, while ignoring the riser on the castings generated thermal interference, so that castings thick Section of the solidification