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目前,铸造界在造型中为节约资源、降低公害,大多数已使用以呋喃树脂为主的有机系粘结剂。但是,在铸钢和球铁生产中使用这类有机粘结剂,容易引起增碳和球化不良等问题。此外,砂温对铸型的硬化情况影响很大,而砂温的控制又很复杂,因此至今在铸钢、不锈钢铸件以及一般中小铸件的铸造厂中依然使用着硅酸钠(即水玻璃)等无机系粘结剂。但是,过去采用这种CO_2造型法,型砂中须加入5～6％水玻璃,粘结剂用量要比有机系粘结剂用得多,而且型砂的溃散性也较差。日本铸造技术普及协会等研制的VRH(真空置换硬化)法,是把加有2～3％水玻璃的混合砂放在气密室内密闭,用真空泵抽空减压后再充入CO_2
At present, the casting industry in the modeling in order to save resources and reduce pollution, most of them have used furan resin-based organic adhesives. However, the use of such organic binders in the production of cast steel and ductile iron tends to cause problems such as carbon build-up and spheroidization. In addition, sand temperature has a great impact on the hardening of the mold, and sand temperature control is very complicated, so far in the cast steel, stainless steel castings and general small and medium-sized castings are still using sodium silicate (ie, water glass) And other inorganic adhesives. However, in the past, this type of CO 2 molding method was used to add 5 to 6% sodium silicate into the molding sand. The amount of binder used was much higher than that of the organic binder, and the collapsibility of the molding sand was also poor. Japan Casting Technology Association and other developed by VRH (vacuum replacement hardening) method is to add 2 ~ 3% mixed with water glass in the airtight chamber sealed with a vacuum pump evacuated and then filled with CO2