过去认为,铸件壁厚愈大,浇注温度应愈低,即所谓“低温快浇”。现经实践证明,这种做法有以下缺点:1.当铁水快速充满型腔后,由于砂型的激冷作用,使铸件与砂型接触的部位在短时间内结成一层外壳(或一层粘稠的冻态外壳)。由于低温快浇,紊流现象严重,铁水中卷入的气体或渣块很难逸出,加工后往往发现有气 In the past that the greater the wall thickness of casting, pouring temperature should be lower, the so-called “low temperature fast pouring.” Practice has proved that this approach has the following shortcomings: 1. When the rapid filling of molten iron cavity, due to the cooling effect of sand, the casting and sand contact with the site in a short time to form a shell (or a layer of sticky Thick, frozen shell). Due to the rapid pouring at low temperature, the turbulence phenomenon is serious, the entrained gas or clinker in the molten iron is difficult to escape, often found after processing gas