论文部分内容阅读
目前,砂型铸造仍广泛利用有机物质作为粘结剂和附加成份。这些有机物质在高温金属液的作用下,产生燃烧,挥发等一系列的物理——化学变化,同时生成大量的气体。若这些气体在型腔内液体金属结壳以前来不及排出,使铸型内部的气体压力大于金属液的压力时,将导致铸件产生侵入性气孔、气隔、浇不足等缺陷。因此,及时测定和控制造型材料的发气性,具有重要的意义。现在国内大多数工厂仍采用“体积法发气
At present, sand casting still widely uses organic substances as binders and additional components. These organic substances produce a series of physico-chemical changes, such as combustion and volatilization, while generating a large amount of gas, under the action of the molten metal at high temperature. If these gases in the cavity liquid metal crust was too late to discharge, the gas pressure inside the mold is greater than the pressure of liquid metal, will lead to invasive casting porosity, air gap, inadequate pouring and other defects. Therefore, timely determination and control of the modeling material of the gas, has important significance. Most factories in China are still using the "volume method of gas