| Casting defect | Cause | Improvement measures |
| White skirt | The temperature of molten aluminum is low, and the heat conduction differential ripening temperature of the outer mold is higher than that of the core mold | Increase the temperature of molten aluminum, improve the heat conduction of outer mold and increase the temperature of core mold |
| Pitting convex concave at skirt pouring | Pouring riser paint splashes on the mold wall; | Sandpaper grinding; |
| Convex and concave at skirt copper plug | The copper plug is convex into the cavity or concave into the die; | Flatten; |
| Oil storage surface hemp spot | Loose texture of outer model cavity wall and graphite peeling results | In case of serious, the external mold is invalid, |
| Concave white of pin hole (junction zone between oil storage surface and ring groove surface) | The heat conduction of the external mold is poor, and the mold temperature is higher than the core temperature; | Improve the heat conduction of the outer mold and increase the temperature of the core mold; |
| Top edge drape | Pad up the external formwork; The base is uneven; | Correct the base; Remove the slag inclusion in the mold base, |
| Top air pocket | The base is cool and the torrent that starts pouring is large; | The temperature of the base rises, and the flow is small and slow at the beginning of pouring; |
| White top | The base is not drained or the water temperature is high; Poor heat conduction of the base, | Enlarge the water inflow and reduce the water temperature |
| The top center hole seat is low and uneven, | Damage and deformation of copper plug or entry of graphite and aluminum slag; | Blow out the cavity; |
| Slag inclusion at skirt and top | If the mold closing force is too large, the core mold will be shaken off and the riser coating will be poured, | Blow out the cavity and close the mold gently; |
| Air pocket on inner wall of stop | The core mold is only covered with water, and air waves are formed during pouring, | Core mould is coated with graphite for thermal insulation |
| Inner wall moire | Core mold cracking | Scrapping in serious cases, |
| The upper part of the outer circle of the pin hole seat is white | High core mold temperature | Cooling of weighted core mold |
| Concave convex at the copper plug on the upper part of the outer circle of the pin hole seat | The copper plug of the core mold is convex or concave, | Strike even, |
| Pin hole blocked | The pin hole core is not inserted into the core mold or inserted too hard on one side, shaking out the core on the other side; | Gently insert both sides at the same time until the core mold; |
| Pin hole arc | Deformation of pin hole mandrel; | Pin hole mandrel scrapped, |
| Air hole on inner wall of pin hole | The water cooling of pin hole mandrel is too cold; Or assembly with water vapor | Thermal insulation of pin hole core mold stained with stone ink |
| The upper part of the inner wall of the pin hole is white | High pin temperature; | Re cooling pin |
| Crack at lower part R of pin hole seat | The core mold rises too early; The core mold is deformed and warped, | Postpone core pulling and pay attention to core pulling mode; The drape joint is too large, the core mold is scrapped, and the aluminum sticking is removed, |
