How to resolve flow mark defects in aluminum alloy die casting?

The flow mark defect in aluminum alloy die casting refers to the marks or grooves that appear on the surface or inside of the aluminum alloy die-cast component. This defect typically occurs during the die casting process when the molten aluminum alloy enters the mold cavity and forms marks or grooves on the surface or inside of the component due to poor flow or other factors.

When flow mark defects occur in aluminum alloy die-castings, the following solutions can be considered. First, let's understand what flow marks are: In normal circumstances, the metal liquid flows in the same direction, forming smooth patterns. However, flow mark defects refer to marks or patterns caused by factors such as changes in the direction of metal flow. Let's explore the solutions in detail:

Flow direction issue: Flow marks occur due to inconsistent metal flow direction. It is necessary to adjust the mold design and optimize the metal flow path to ensure that it flows in the same direction, reducing the occurrence of flow marks.

Temperature control: Adjusting the mold temperature is crucial. For zinc alloy, the mold temperature should be kept below 150°C, while for aluminum alloy, it should be below 180°C. By properly adjusting the temperature, the fluidity of the metal can be improved, reducing the occurrence of flow marks.

Fill speed: Both too fast and too slow fill speeds can lead to flow mark defects. It is necessary to adjust the fill speed according to the specific situation to achieve a moderate speed. This ensures that the metal adequately fills the mold cavity, avoiding the occurrence of flow marks.

Coating application: Using a thin and uniform coating can improve the friction between the metal and the mold wall during the filling process, reducing the formation of flow marks. Pay attention to selecting a suitable coating and ensure even application.

Gate design: Adjust the cross-sectional area and position of the gate. Proper gate design can improve the flow state during metal filling, reducing the occurrence of flow marks.

By paying attention to the above methods and implementing the suggested measures, it is possible to effectively prevent the occurrence of flow mark defects in aluminum alloy die castings.