三乙胺法冷芯盒砂芯抗拉强度性能的研究

Research on tensile strength properties of cold box sand cores by triethylamine method

三乙胺法冷芯盒砂芯的抗拉强度受到环境湿度、存放时间以及涂料种类的影响。试验结果证明:砂芯存放在干燥环境中30天,抗拉强度达到终强度后保持恒定不变;存放在生产现场(环境湿度45%RH~65%RH)30天,抗拉强度先增大后减小,衰减35.9%;浸涂水基涂料和醇基涂料后,砂芯抗拉强度大幅降低,水基涂料导致砂芯抗拉强度降低更加严重。砂芯在一定的环境湿度下存放,抗拉强度随时间的延长而降低,通过加热烘干后强度保持不变,证明以聚氨酯粘结膜为主要成分的树脂粘结桥结构发生水解反应后,受到的破坏是不可逆的。

The tensile strength of the cold box sand core by triethylamine method is affected by the environmental humidity,storage time and the type of coating.The experimental results show that:the sand core is stored in a dry environment for 30 days,and the tensile strength remains constant after reaching the final strength.When stored in the production site(environmental humidity 45%RH~65%RH)for 30 days,the tensile strength increases first.After dipping the water-based paint and alcohol-based paint,the tensile strength of the sand core is greatly reduced,and the water-based coating leads to a more serious decrease in the tensile strength of the sand core;the sand core is stored in a certain ambient humidity,while the tensile strength decreases with time,and the strength remains unchanged after heating and drying,which proves that the damage of the resin bonding bridge structure with polyurethane bonding film as the main component is irreversible after the hydrolysis reaction.