Brass casting process flow

Brass casting is actually an early metal hot working process. Brass casting technology has a history of about 6000 years. The definition of brass casting process: refers to the processing method of melting solid brass into liquid brass and pouring it into a mold with a specific shape for solidification. Besides casting brass, copper, iron, aluminum, tin and lead can also be cast. The materials of ordinary molds include raw sand, clay, water glass, resin and other auxiliary materials. Special casting molds include: investment casting, lost foam casting, metal mold casting, ceramic mold casting, etc. (Raw sand includes quartz sand, magnesia, zircon sand, chromite sand, forsterite sand, kyanite sand, graphite sand, iron sand, etc. ).

The lowest temperature required by brass casting process: generally speaking, it is 960 degrees, which is almost crystallized. Generally at least 980 degrees, which is the lowest casting temperature. This is high zinc brass, and low zinc brass is higher.

Advantages of brass casting process: low manufacturing cost and great process flexibility, and large castings with complex shapes can be obtained, which account for a large proportion in machinery manufacturing, such as machine tools accounting for 60-80%, automobiles accounting for 25% and tractors accounting for 50-60%.

Commonly used brass casting methods: There are generally three kinds of brass casting methods, which have been proved to be suitable for brass casting. Metal casters can be tested in different ways and should not be restricted.

1, lost wax casting:

Lost wax is usually used to cast bronze castings, but it can also be used for brass and any other metal. By using a wax mold and covering it with a ceramic shell, craftsmen can inject molten alloy instead of wax. A small shell will expose a brass sheet. Lost wax casting is a detail that needs great attention when using. Artists or metal casting unions who create decorative copper sheets or sculptures find that lost wax casting technology will meet their needs far better than other technologies and methods.

2, die casting:

Another method of casting die-casting brass. Die casting is usually used in commercial foundries because the initial start-up cost of small foundries is very low. By creating a reusable mold, the foundry will be able to make the same fraction of products from steel. If a foundry or artist plans to make a multiple of a product, he can find a feasible market and should use a mold made of brass.

3, sand casting:

Sand casting is probably the oldest casting, and it is still a common method, especially for small foundries. Brass poured into sand mold can create a unique appearance, which may be the first choice for craftsmen. Sand casting is often the most economical and reasonable small foundry. If the casting is not very attractive, then this method is desirable.

Brass casting process usually includes:

1. Prepare the mold (container for making liquid metal into solid castings). According to the materials used, molds can be divided into sand mold, metal mold, ceramic mold, clay mold, graphite mold and so on. According to the times of use, it can be divided into disposable molds, semi-permanent molds and permanent molds. Mold quality is the main factor affecting the quality of castings;

2. Melting and pouring of casting metal. Casting metals (casting alloys) mainly include various types of cast iron, cast steel and cast nonferrous metals and alloys;

3. Casting treatment and inspection. Casting treatment includes removing foreign bodies from the core and the surface of the casting, cutting off the riser, shoveling off burrs, overlapping seams and other protrusions, as well as heat treatment, shaping, rust prevention and rough machining.

The casting process can be divided into three basic parts, namely, casting metal preparation, mold preparation and casting treatment. Casting metal refers to the metal material used to pour castings in casting production. It is an alloy with a metallic element as the main component and other metallic or nonmetallic elements. Traditionally called cast alloy, it mainly includes cast iron, cast steel and cast nonferrous alloy.

Methods to improve the hardness of brass castings;

Trace cobalt (0.2%, 0.4%, 0.6%) was added to aluminum brass (72.5Cu-22.7Zn-3.4Al), and the effects of trace cobalt, casting process and process parameters on the mechanical properties of strip produced by rolling method were studied. Explore the use of aluminum brass to replace the widely used elastic copper alloy material. The feasibility study of Sn-P bronze shows that cobalt can effectively reduce the grain size of as-cast alloy, change the grain shape, improve the tensile strength and hardness of the alloy, and ensure the alloy has good plasticity. 0.4% cobalt is added to aluminum brass. Brass strip produced by reasonable processing technology has better properties than tin phosphorus bronze. The tensile strength of 0.25mm thick strip can reach 840.4MPa and the elongation is 2.8%. The Vickers hardness value is 228, and the maximum tensile strength (805MPa) of QSn6.5-0. 1 strip in the hard state of the drill bit is increased by 4.4%, which meets the requirements of elastic elements. At the same time, because brass contains 22.7% zinc, it can effectively reduce the cost and has practical application value.