水玻璃砂的加热真空硬化法（HVH）

Heating Vacuum Hardening Process of Sodium Silicate Sand

在深入分析ＶＲＨ法和热芯盒制芯法优缺点的基础上，提出了对砂芯进行１００℃预热，再在加热条件下抽真空硬化的ＨＶＨ制芯方法。采用这种方法制取水玻璃砂芯时，水玻璃加入量可降到２．５％，砂芯强度可达１．３６～１．４６ＭＰａ，而且工艺工装比较简单，砂芯硬化速度快，生产率比较高，砂芯溃散性得到明显改善。

Based on survey of Conventional VRH process and hot box process, the heating vacuum hardening process of sodium silicate bonded sand (HVH process) has been deve loped, the hardening procedure of which is as follows: after preheated at 100℃, the core is then hardened by heating and vacuum. With this process, the addition of sodium silicate can be reduced to. 2.5 % and the core strength of 1. 36￣1.46 MPa can be achieved. The HVH process has technical adventages over the traditional coremaking method in terms of simple processing equipment, higher productivity, shorter core hardening time and better collapsibility.