Lost Foam Casting---The Effect of Foam Pattern Density on the Quality of Castings

1. The effect of high-density patterns on castings:

The mold filling process of lost foam casting is that the foam pattern in the cavity softens, collapses, melts until it is vaporized decomposed under the action of the front of the flowing metal liquid. The resulting liquid products gaseous products (including air in the beads) After the metal foam pattern interface reaches the metal/coating/foam pattern, metal/coating interface, it enters the molding sand through the paint is discharged into a series of complex physical chemical reactions (including secondary decomposition condensation).

The raw material of the pattern is mainly foam plastic, which is made of synthetic resin as the base material. Regardless of the shape of the material, there is much carbon.

In the mold filling process of lost foam casting, the pyrolysis of the foam pattern is an endothermic reaction. In this process, if the density of the pattern is too high, it will inevitably absorb a lot of heat in the molten iron (molten steel), causing the gasification decomposition of the pattern. Thoroughly, the casting has wrinkled skin carbon defects.