磺酸自硬树脂砂引起球铁件表层组织变异原因和防止措施研究

Abnormal Structure at the Surface Layer of Nodular (SG)Iron Castings Produced by Sulfonic Acid Cured Sand Mold: Causes and Preventions

本文设计了一个专用装置研究SO2气体对稀土镁球铁件组织的影响。研究表明,SO2气体吸附在铸件的表面离解成硫原子后扩散进入铸件表层一定深度,同其中的Mg、RE和Mn反应形成硫化物,从而使石墨球化和稳定珠光体的有效元素含量不足,导致铸件表层出现异常组织。当用对甲苯磺酸作催化剂的呋喃树脂自硬砂生产稀土镁球铁件时,由于对甲苯磺酸在铁液浇注和凝固过程中受热作用分解出SO2气体,导致铸件表层出现异常组织,采用反应型或屏蔽型涂料可有效防止球铁件表层异常组织缺陷。

The paper sets up an experimental design study of a special device SO2 gas on RE-Mg Nodular Iron Castings Organization, which shows that： SO2 gases adsorbed on the surface of castings dissociation into sulfur-proliferation into the casting surface after a certain depth, with one of Mg, RE and Mn response to the formation of sulfide, so that the stability of graphite and pearlite spheroidization elements less than effective, leading to abnormal organization casting surface. When p-toluenesulfonic acid as catalyst of Furan Resin Sand production of magnesium rare-earth iron ball, as p-toluenesulfonic acid in the casting and solidification of molten iron, the heat decomposition of the role of SO2 gas, resulting in unusual surface casting organizations. Or the use of reactive coatings can be effectively shielded to prevent pieces of ductile iron surface defects in abnormal organization.