Today aluminum foundry with everyone to analyze several aluminum die-casting defects, as follows:

1. Flow marks and pattern

There is a stripe that is consistent with the flow direction of the metal liquid on the surface of the casting, and there is no direction in which the color of the metal is not the same as that of the metal matrix, and there is no trend of development.

Reason:

1. Low die temperature or low temperature of

2. Poor runner design and poor gate location;

3. The filling speed is low and the filling time is short;

4. The pouring system is not reasonable;

5. Bad exhaust or irrationality of spray

Two, reticulate wingwing, that is, tortoise crack

On the surface of die castings, traces of bulge or dent appear on the surface of the die, and expand and extend with the increase of die casting times.

The reason is that there are cracks on the surface of the die casting die, and the die casting die is preheated unevenly.

Three. Cold septum

On the surface of the die casting, there are obvious, irregular and subsidence linear patterns (with two kinds of penetration and non penetration) small and narrow in shape, sometimes smooth on the edge of the intersection, and the possibility of breaking off under external force.

Reason:

1, the two metal streams are joined to each other, but they are not completely fused without inclusion. The two metal bonding force is very weak;

2, pouring temperature or die casting die temperature is low;

3. The position of the runner is wrong or the flow is too long;

4. The filling speed is low.

Four, the contraction, that is, the dent

On the surface of die casting parts, there are smooth dents (like discs) on the surface.

The reasons are as follows:

1. Improper design of die castings caused by shrinkage, wall thickness difference is too large;

2. Improper location of runner, compression ratio, short holding time and high local temperature of die casting die.

3. The design of cooling system is not reasonable;

4, the model is premature;

5, the pouring temperature is too high.

Five, imprint

The traces left on the surface of the casting die contact with the die casting cavity surface or ladder marks on the surface of the casting.

Cause: caused by ejector elements or caused by splicing or moving parts.