In the process of using shot blasting machine, if we can deal with some problems through experience, it will reduce the operating cost of the equipment and speed up the production speed.
If there is a thin skin on the surface of the casting after shot blasting, it will be cocked up or even fall off, which can be easily picked off by hand, and the size, area and position are not fixed. This phenomenon is called peeling after shot blasting in die casting.
Why is there the problem of peeling of castings after shot blasting? After years of experience in shot blasting, the following six situations are summarized:
1. The casting is not compacted, and the surface has casting defects such as cold shuts, delaminations, bubbles and poor alloy flow fusion.
2. The ejection speed of steel shot is too high.
3. Shot peening time is too long.
4. The pendant method is unreasonable, unstable and bumped against each other.
5. The shape and quality of steel shot are poor and not smooth.
6. The steel shot contains sharp impurities.
Facing these situations, we should deal with them in this way:
1. The casting surface is dark. Inform the die-casting process or the Engineer in charge to adjust the die-casting process parameters or equipment parameters;
2. Properly reduce the steel shot ejection speed of the shot peening machine;
3. Reduce shot peening time appropriately;
4. Reasonable hangers shall be used to ensure that the castings are fixed during shot peening, and special fixtures can be used when necessary;
5. Purchase steel balls with regular shapes;
6. Screen the steel shot or replace the steel shot.
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