The formation process of cast aluminium components during casting

During the casting process, aluminium castings are prone to internal defects such as porosity, shrinkage cavities, and gas holes. When these defective castings undergo machining, the surface dense layer is removed, exposing the underlying structural flaws. For automotive cast aluminium components requiring sealing integrity—such as cylinder blocks, cylinder heads, intake manifolds, and brake valve bodies—the presence of micro-pores during pressure sealing tests leads to leakage of sealing media, resulting in significant scrap rates. Crucially, these defects often remain undetected until post-machining pressure testing, causing substantial wastage of labour, raw materials, and energy. To address the high scrap rate of automotive cast aluminium components and salvage castings potentially scrapped due to such defects, remedial measures must be implemented during production. The employed technique is impregnation treatment, specifically leak sealing. Impregnation involves introducing a penetrant into the micro-pores of cast aluminium components under controlled conditions. Upon curing, the infiltrated filler material bonds with the pore walls, sealing the micro-voids. This process enables the components to meet requirements for pressurisation, leak prevention, and sealing integrity.
During the casting process, aluminium castings are prone to internal defects such as porosity, shrinkage cavities, and gas holes. When these defective castings undergo machining, the surface dense layer is removed, exposing the underlying structural flaws. For automotive aluminium castings requiring sealing integrity—such as cylinder blocks, cylinder heads, intake manifolds, and brake valve bodies—the presence of micro-pores during pressure sealing tests leads to leakage of sealing media, resulting in substantial scrap rates. Crucially, these defects often remain undetected until post-machining pressure testing, causing significant wastage of labour, raw materials, and energy. To address the high scrap rate of automotive cast aluminium components and salvage castings potentially scrapped due to such defects, remedial measures must be implemented during production. The employed technique is impregnation treatment, specifically leak sealing. Impregnation involves introducing an impregnating agent into the micro-pores of cast aluminium components under controlled conditions. Upon curing, the infiltrated filler material bonds with the inner walls of the pores, sealing the micro-voids. This process enables the components to meet requirements for pressurisation, leak prevention, and sealing integrity.