Five Major Defects In Mold Casting

- Aug 17, 2018-

3. Cracks in castings


There are two main reasons. First, the metal is usually solidified too quickly, causing casting defects (seam); the second is cracking due to high temperature.


(1) For the metal to solidify too quickly, the resulting cast seam can be solved by controlling the casting time and solidification time.


Relevant factors of casting time:

1) The shape of the wax type.

2) The amount of thickness cast.

3) Casting pressure (casting machine).

4) The permeability of the embedded material.


Related factors of solidification time:

1) The shape of the wax type.

2) The highest firing temperature of the cast ring.

3) Type of embedding material.

4) Type of metal.

5) The temperature of the casting.


(2) Cracks due to high temperatures are related to the mechanical properties of metals and embedded materials.


Cracks are easy to occur in the following cases:

1) High casting temperature is prone to cracking;

2) The embedded material with high strength is prone to cracking;

3) Nickel alloys and cobalt alloys with small elongation are prone to cracking.


The solution:

1) using a low-strength embedding material;

2) Minimize the casting temperature of the metal;

3) Do not use alloys that are less ductile and brittle.