Defects that occur frequently in die casting.

In the actual production process of the foundry, it is often encountered with such product problems by using die casting precess.

This is a summary of the article, to record the defects, analyze the possible reasons to help us solve the product problem.

1. Flow mark and pattern

Appearance inspection:
The surface of the casting is in the same direction as the flow direction of the metal liquid, and there is obviously a non-directional pattern that is not the same as that of the metal matrix, and there is no development trend.

The causes of flow marks are as follows:
(1) the mold temperature is too low;
(2) poor sprue design and poor internal gate position;
(3) the material temperature is too low;
(4) low filling speed and short filling time;
(5) the pouring system is not reasonable;
(6) poor ventilation;
(7) spray is not reasonable.

2. Reticular hair wing (turtle crack)

Appearance inspection:
The surface of the die casting has the appearance of a network hairline, and it enlarges and extends as the number of die casting increases.

The reasons are as follows:
(1) cracks in the cavity surface of the die casting mold;
(2) preheating of die casting mould is not uniform.

3. Sinking linear pattern.

Appearance inspection:
Die casting surface has obvious linear type, irregular, subsidence of grain shape (a through and not through two) small and narrow, sometimes smooth transition edge, under the action of external force has the potential to disconnect.

The reasons are as follows:
(1) the two metal flows are connected with each other, but they are not completely fused and there is no inclusion.
(2) the casting temperature or mold temperature is low;
(3) the gate position is not right or the flow is passing by;
(4) low filling speed.