排气片工艺消除球墨铸铁件厚大部位收缩缺陷

Shrinkage Defects of Ductile Iron Thick Parts Eliminated by Exhaust Slices Process

在球墨铸铁件厚大部位表面设置排气片,试图消除铸件内部缩松缺陷,并初步探讨排气片工艺消除球墨铸铁件内部缩松的工艺原理。结果表明:排气片在铸件凝固时可以对其形成液态静压力,进而起到补缩作用。当铸件表层形成坚硬凝固壳时,排气片根部也完全凝固,可以有效抵御球墨铸铁石墨化共晶膨胀对排气片的压力,从而有效抵消铸件内部凝固时产生的缩松缺陷。排气片工艺既可消除球墨铸铁件内部缩松,又可提高工艺出品率,经济效益明显。

Exhaust slices were placed on the surface of the ductile iron thick parts, which were used to eliminate shrinkage defects of the castings, and the process principle was discussed. The results show that the solidification of the exhaust slices can form liquid static pressure for the castings, and then play feeding role. When a hard shell is formed on the casting surface, the exhaust slices solidify completely also. The hard shell can resist the pressure of graphite eutectic expansion forming effectively, and then the shrinkage defects during solidification can be eliminated effectively. Exhaust slices process can not only eliminate the ductile iron internal shrinkage, but also improve the process yield, and the economic benefits have increased significantly.