Casting Brass

Brass is by definition an alloy of copper and zinc. From this basic combination, several types of casting brass were developed, either including other metals in the formula, or varying the concentration of metals present in the alloy.

As for the metal criteria use, there is casting brass and brass for cold worked. Fundição Magma produces and commercializes ingots of ten different types of brass to be used in both forms.

Casting Brass Characteristics

The main characteristic of casting brass, in relation to brass to be cold worked is the lower malleability, due to the additional percentage of zinc. Though less ductile, casting brass is stronger.

Casting brass is a complex process, requiring specialized technical skills and appropriate equipment and tools for its performance. All this due to the relatively high brass melting point, which is between 900ºC and 940ºC.

At this temperature, the brass reaches its liquidus state and is then poured into the mold with the geometry of the part to be produced. The casting brass process makes it possible to manufacture pieces with complex shapes and with a good cost-effectiveness.

Regardless of the characteristics of the brass to be chosen, different techniques can be used to casting brass parts. The choice of the best method should consider three basic factors:

• Dimension of the part to be produced
• Production cost
• Quantity of parts to be produced

The most commonly used casting brass techniques are:

Shell casting: Liquid brass is poured into a mold by gravity, using manual or hydraulic tools. It is indicated for parts that require a perfect finish and a medium level of productivity. The mold used can be used several times and the rate of raw material loss is low – factors that reduce production costs.

Green sand-casting mold: Technique that uses a mold or compacted model with green sand, forming a sand cake. The liquid brass is poured into this mold to produce the desired piece. Green sand results from a mixture of bentonite and water. The technique is used to manufacture simpler parts, which do not require exact measurements. The cost of the process is lower than that of shell casting.