轿车重熔淬火凸轮轴壳型铸造技术

介绍重熔淬火硬化处理凸轮轴工艺,以及供重熔淬火用的壳型凸轮轴的生产工艺.凸轮面针孔是凸轮轴重熔淬火工艺容易产生的质量问题.研究发现,其主要原因是铸件重熔面含氧量较高,微观夹杂较多,次要因素是凸轮重熔面组织粗大.防止方法是降低铸件的含氧量,防止氧或杂质渗入凸轮表层,以及细化金相组织.

Production Technique of Shell-Mold Sedan Camshaft Castings to be Surface Re-Melted and Chilled

The sedan camshafts re-melting and chilling process and production technique of shell mold camshaft castings to be re-melted and chilled were introduced. Pinholes are the defects often found in cam surface layer after re-melted and chilled. It was revealed after investigation that high oxygen content and too many micro-inclusions in the surface layer to be re-melted were the main reason causing this type of defect, and the open structure of the surface layer to be re-melted was the secondary reason. Therefore, to prevent this type of defect, it is necessary to reduce oxygen content of castings, avoid oxygen or inclusions penetrating into cam surface layer, as well as to fine the microstructure of the surface layer.