| Casting defect | Cause | Improvement measures |
| Unqualified chemical composition | The composition of master alloy ingot is unqualified, and the burden of electric furnace smelting is not allowed | Selection of master alloy ingot ingredients |
| Macro dispersed pores and slag inclusion > grade 4 | Insufficient degassing, static and slag raking of electric furnace; Unqualified aluminum water is scooped during pouring; Low temperature of molten aluminum | Degassing shall be carried out carefully to ensure that the slag is removed during the static time before pouring; Increase the temperature of molten aluminum; |
| Macro concentrated pores and slag inclusion > grade 4 | Insufficient degassing, static and slag raking of electric furnace; Unqualified aluminum water is scooped during pouring; When the temperature of molten aluminum is low, scoop the molten aluminum into it; | Pay attention to pushing slag and scooping aluminum water; |
| Unqualified metallographic structure > grade 5 | Insufficient degassing, static and slag raking of electric furnace; Unqualified aluminum water is scooped during pouring; Low temperature of molten aluminum, | Degassing shall be carried out carefully to ensure that the slag is removed during the static time before pouring; Increase the temperature of molten aluminum; |
| Hardness less than HB100 | Poor heat conduction of external mold and heat transfer of base | Improve the heat conduction of the external mold and reduce the water temperature |
| Insufficient tensile strength | ZL108 has poor deterioration effect, poor heat conduction of external mold and hot base | Scrap the outer mold and reduce the water temperature |
| Ring groove shrinkage and looseness | Thermal conductivity difference of external mold, mold ° C > core ° C | Improve the heat conduction of the outer mold and increase the temperature of the core mold by ° C |
| Slag inclusion hole in pin hole | Pin hole core die is too cold; Or assembly with water vapor | Thermal insulation of pin hole core mold stained with stone ink |
| Slag inclusion air hole at wall and stop end | Insufficient degassing, static and slag raking of electric furnace; Unqualified aluminum water is scooped during pouring; Low temperature of molten aluminum | Degassing shall be carried out carefully to ensure that the slag is removed during the static time before pouring; Increase the temperature of molten aluminum; |
| Pin hole crack | Core pulling die is too early, and the core die is deformed; | Postpone the core pulling die and pay attention to the mode of core pulling. The core die is deformed and seriously scrapped. |
