磷酸盐自硬砂用氧化铁复合固化剂研究

Study on the Iron Oxide Composite Hardener in Phosphate No-bake Sand

过向单一氧化镁固化剂中加入氧化铁粉末,配制复合固化剂。研究表明使用该种复合固化剂后磷酸盐自硬砂的抗拉强度提高达60%以上,砂型存放稳定性也得到改善。改变氧化铁与氧化镁的配比量,发现其对砂型强度的影响呈非线性关系,当其含20%氧化铁时砂型试样能得到最高抗拉强度,当其含30%氧化铁时砂型试样有最好的存放稳定性。将自硬砂置于高湿(﹥90%RH)环境下超过24 h,自硬砂会变软并且强度下降。

By adding iron oxide to the unitary magnesium oxide,a composite harder is prepared.The results showed that the composite harder can increase the tensile strength of phosphate no-bake sand more than 60%,the store stability of phosphate no-bake sand was also improved.Changing the percentage of the iron oxide,it showed that the addition quantity of iron oxide and the property of sand was nonlinearity.The highest tensile strength was obtained by 20% content of iron oxide based on total composite hardener.But a higher sand store stability was attained by 30% iron oxide.Putting this no-bake sand under high humidity（more than 90%RH）condition for 24 hours,the no-bake sand become flexible and the tensile strength is decreased.