关键词: 电熔镁铝尖晶石, 树脂加入量, SiC粉, 工艺优化, 棒头

Abstract: Stoppers are an important flow-controlling component in continuous casting.Aluminum-carbon stopper heads are often damaged due to poor corrosion resistance,thermal shock resistance,and oxidation resistance during smelting high-oxygen and high-manganese steel,which leads to the flow-controlling failure of stoppers.Stopper head materials were prepared using fused magnesium aluminate spinel,flake graphite,Si powder,and SiC powder as main raw materials,powdered phenolic resin as the binder,and industrial alcohol as the solvent.The effects of resin additions (6%,7%,8%,and 9%,by mass) and SiC powder additions (1%,2%,3%,5%,and 8%,by mass) on the performance of the stopper heads were studied,and the head structure process was optimized.The result shows that when the resin addition is 7%,the material achieves the highest densification degree with a density of 2.65 g·cm^-3,and its cold and hot mechanical properties are optimal:the cold compressive strength of 41 MPa,the cold modulus of rupture of 14.3 MPa,and the hot modulus of rupture of 7.3 MPa.On this basis,adding 3% SiC powder can improve the thermal shock resistance and oxidation resistance of the head while ensuring its mechanical properties.In addition,optimizing the structural process to change the contact area between the head and the main body increases the fracture surface energy of the head,thus reduces the occurrence of head dropping,and improves the reliability of the stopper.

Key words: fused magnesium aluminate spinel, resin addition, SiC powder, process optimization, stopper head