Brass fittings processing technology

Definition: Brass processing refers to the process of adding or reducing the content of certain elements, or changing the shape and state of a certain process, to produce a finished product that meets people's requirements.

Brass is an alloy of copper and zinc. If only brass made of copper and zinc is called ordinary brass. Brass is often used in the manufacture of valves, water pipes, air conditioning inside and outside machine connections and radiators. Brass alloys containing less than 36% zinc are composed of solid solution and have good cold workability. For example, brass containing 30% zinc is commonly used to make bullet casings, commonly known as cartridge brass or seven-three brass. Brass alloys containing between 36 and 42% zinc are composed of solid solution, the most common of which is 40% brass with 40% zinc. In order to improve the performance of ordinary brass, other elements such as aluminum, nickel, manganese, tin, silicon, lead, etc. are often added.

Ordinary brass processing pressure processing performance:

α single-phase brass (from H96 to H65) has good plasticity and can withstand hot and cold processing, but α-phase brass is prone to moderate temperature brittleness during hot working such as forging, and its specific temperature range varies with the amount of Zn. The change is generally between 200 and 700 °C. Therefore, the temperature during hot working should be higher than 700 °C. The reason why the medium-temperature α-brass medium-temperature brittle zone is mainly caused by the presence of two ordered compounds of Cu3Zn and Cu9Zn in the α-phase region of the Cu-Zn alloy system, which undergoes orderly transformation during medium-low temperature heating, making the alloy brittle; There is a trace amount of lead, antimony harmful impurities and copper forming a low-melting eutectic film distributed on the grain boundary in the alloy, and intergranular cracking occurs during hot working. Practice has shown that the addition of trace amounts of strontium can effectively eliminate moderate temperature brittleness.

Two-phase brass (from H63 to H59), in addition to a well-plastic α phase in the alloy structure, a β-solid solution based on the electron compound CuZn has appeared. The β phase has a high plasticity at high temperatures, while the β' phase (ordered solid solution) at low temperatures is hard and brittle. Therefore, (α + β) brass should be forged in the hot state. The beta brass containing more than 46% to 50% of zinc has a hard and brittle performance and cannot be subjected to pressure processing.

Cast brass brass processing:

Casting brass composition ratio: copper 60.0-63.0%, total impurities 1.5%, the rest is zinc;

Copper-zinc alloys with a total copper content of about 57%-68%. Other elements can only be used for casting at around 3%. As long as there is not much waste bronze (the lead ratio is too high), it is melted together. The cast of brass is miscellaneous.