Views: 377 Author: Site Editor Publish Time: 2018-06-11 Origin: Site
In the die casting industry, it is well known that surface defects of die-casting pieces are very common, and there are many kinds of defects. In diffident areas they have different names such as flow marks, or stripes. The question is how does the cast-down flow mark occur? Is there any way to fix it? What are flow marks of die-casting pieces?
The main characteristics of flow marks of die casting parts are that the surface of the casting is consistent with the flow direction of metal liquid, and the local depression smooth lines are obtained by hand feeling. The flow mark defect has no development direction and can be removed by polishing method.
How are the flow marks produced in die casting pieces? Several causes of flow marks are analyzed as below:
1. Two streams of metal fill the cavity out of sync and leave the trace.
2. Mold temperature is low. If zinc alloy mold temperature < 150 ℃, or aluminum alloy mold temperature < 180 ℃, it is easy to produce this kind of defect.
3. Too high filling speed.
4. Excessive amount of coating material.
How to eliminate flow mark defect of die casting parts? After discussing the reasons and we have some solutions to solve this problem.
1. Adjust the section area or position of the gate.
2. Adjust mould temperature to increase overflow tank.
3. Adjust the filling speed to change the flow state of the metal liquid during the filling process.
4. Use thin and uniform coating.