水玻璃型壳熔模铸造制壳工艺的环保化改进

Environment-protecting Improvement of Shell Mould-making Process Used in Sodium Silicate Investment Casting Production

介绍了水玻璃型壳熔模铸造制壳工艺的工艺流程,分析了NH_3浓度大的原因:采用NH4Cl做硬化剂产生了刺激性NH_3气体;同时在制壳过程中风干时以及在制壳完毕后的停放风干这段时间里,因型壳内还有大量水分,所以也会不断产生NH_3。通过合理选用加固层硬化材料,加强结晶AlCl_3·6H_2O硬化剂工艺参数的控制和检测,调整加固层其他制壳参数,降低型壳厚度等措施,消除了近80%的NH_3味,改善了车间环境;同时在保证型壳强度的基础上,减少了制壳层数,节省材料和人工费用,降低了生产成本。

The process flow of the shell mould making process used in sodium silicate investment casting production was introduced. The reason causing the concentration of NH3 too high was analyzed:the used hardener NH4Cl produced irritant NH3 gas,big amount of moisture still existing in the shell mould making process and in the air drying process after shell making having been finished,this moisture also could produce NH3. By through rationally choosing the hardening material,enforcing control and inspection of process parameters of AlCl3·6H2O crystal hardener,adjusting other shell mould making parameters,reducing shell mould thickness,about 80% of NH3 smell was eliminated that improved the shop environment,at the same time,on the basis of ensuring the shell mould strength,the shell layers number was reduced that saved material and labour expense and decreased production cost.