HIS COPPER AND ALLOY
- preliminary
Copper is a reddish brown soft metal, is ductile, corrosion and weather resistant and is a good conductor of electricity. In the industry most of the use of copper is used as a wire or change to heat exchangers in utilizing electricity and heat in other words copper is a chemical element in the periodic table which has the symbol Cu and atomic number 29. The symbol comes from the Latin Cuprum. Copper is a good conductor of heat and electricity. In addition this element has a very fast corrosion. Pure copper is smooth and soft, with a reddish orange surface. Copper is mixed with tin to make bronze.
- Brass copper
The main component of brass is copper. Total copper content varies from 55% to 95% by weight depending on the type of brass and the intended use of brass. Brass which contains a high percentage of copper is made from copper which is purified electrically. Which at least produces 99.3% pure brass so that the amount of other materials can be minimized. Brass that contains a low percentage of copper can also be made from electrically purified copper, but is more often made from scrap copper. When the recycling process takes place, the percentage of copper and other materials must be known so that the manufacturer can adjust the amount of material to be added to achieve the desired brass composition.
The second component of brass is zinc. The amount of zinc varies from 5% to 40% by weight depending on the type of brass. Brass with a higher percentage of zinc has stronger and harder properties, but is also more difficult to form, and has less corrosion resistance. Zinc that is used to make brass of commercial value is known as a spelter. Some brass also contains a small percentage of other materials to produce certain characteristics, up to 3.8% by weight. Lead can be added to increase endurance. The addition of tin increases corrosion resistance, making brass harder and making smaller internal structures so that brass can be formed repeatedly in a process called forging. Arsenic and antimony are sometimes added to brass containing more than 20% zinc to inhibit corrosion. Other materials that can be used in very small quantities are manganese, silicon, and phosphorus
- Types of brass copper types
- Brass Admiralty, Contains 30% zinc, and 1.5% lead.
- Brass Aich, containing 60.66% copper, 36.58% zinc, 1.01% lead, and 1.74% iron. Designed for use in marine services because of its corrosion-resistant, hard, and tough nature.
- Brass Alpha, Has a zinc content of less than 35%. Works well in cold temperatures.
- Alpha-beta brass (Muntz), often also referred to as duplex brass, contains 35-45% zinc, works well at hot temperatures.
- Brass Aluminum, Containing aluminum which results in increased corrosion and rust resistance properties.
- Arsenic Brass, Contains the addition of arsenic and aluminum.
- Brass Cartridge, containing 30% zinc, has good working properties at cold temperatures.
- General brass or brass rivets, containing 37% zinc, cheap and good standard of working properties at cold temperatures.
- Brass DZR or dezincification, is brass with a small percentage of arsenic.
- High Brass, containing 65% copper and 35% zinc, has high tensile strength, widely used for springs, screws, and rivets.
- Leaded Brass.
- Lead Free Brass.
- Low Brass, copper-zinc alloy containing 20% zinc, has golden color properties.
- Brass Manganese, brass used in making gold dollar coins in the United States. Contains 70% copper, 29% zinc, and 1.3% manganese.
- Brass nickel, consisting of 70% copper, 24.5% zinc, and 5.5% nickel. used to make Pounds Sterling coins.
- Navy Brass, similar to admiralty brass, contains 40% zinc and 1% lead.
- Kuningan Merah, containing 85% copper, 5% lead, 5% lead, and 5% zinc.
- Brass Tombac, containing 15% zinc. Often used in jewelry product applications.
- Tonval Brass (Also called CW617N or CZ122 or OT58), copper-lead-zinc alloy.
- White Brass, containing more than 50% zinc. Very fragile for general use.
- Yellow Brass, is the American term for brass which contains 33% zinc
- Brass copper function
- So that materials / products are not easily corroded
- Copper in brass makes brass antiseptic, passing through an oligodynamic effect. For example, brass door handles can disinfect themselves from many bacteria within 8 hours
- The benefits of copper in the electricity sector are arguably very vital. Besides silver, copper is the most effective conductor of electricity
iii. The process of making brass copper
- Melting
An appropriate amount of copper material according to the dose of the alloy is weighed and transferred to the melting furnace at temperatures around 1920 ° F (1050 ° C). An amount of zinc that has been weighed to fit the alloy is prepared, zinc is added after the copper has melted. About 50% of the total zinc can be added to compensate for the zinc that evaporates during the smelting operation between copper and zinc. If there are other materials needed for the formulation of certain brass they can also be added.
Liquid metal alloys of copper and zinc are poured into the mold. It is permissible to strengthen into sheets. In some pouring operations carried out continuously to produce a long sheet.
When the liquid metal alloys of copper and zinc are cold enough to be removed, they are removed from the mold and moved to a storage area.
- Hot Rolling
The metal is placed in a furnace and heated until it reaches the desired temperature. The temperature depends on the final shape and nature of the brass. The heated metal is then proceeded to the milling machine. brass, which is now cold past a milling machine called a scalper. This machine will cut a thin layer from the outer surface of the brass to remove oxides that may have formed on the surface as a result of exposure to hot metal to the air.
Anealing and Cold Rolling
In the hot rolling process the brass loses its ability to be extended further. Before brass can be extended further, it must first be heated to alleviate the hardness and make it more resilient. This process is called annealing. Annealing temperature varies according to brass composition and desired properties. In this method, the atmosphere inside the furnace is filled with neutral gases such as nitrogen to prevent the brass from reacting with oxygen and forming unwanted oxides on its surface.
The results of the previous process are then passed through a series of other rollers to reduce their thickness to around 2.5 mm. This process is called cold rolling because the temperature of the brass is much lower than the temperature during hot rolling. Cold rolling results in deformation of the internal structure of brass, and increases strength and hardness. The more thickness decreases, the stronger the brass that is created.
Steps 1 and 2 of annealing and cold rolling can be repeated many times to achieve the desired brass thickness, strength, and degree of hardness.
At this point, the above process produces brass strips. The brass strip can then be acidic to clean it.
Finish Rolling Brass strips may be given cold rolling end to tighten the tolerance to thickness or to produce a very smooth surface finish. They are then cut to size, stacked, and sent to industrial houses. The brass strip may also be given a final rolling before it is cut long, rolled, sent to the warehouse, and stored.
- Brass copper products
REFERENCE
https://www.kompasiana.com/hermansantoso/55099149813311490eb1e1cd/process-making-kuningan-from-logam
https://slideplayer.info/slide/16978606/
https://www.pengrajinkuningan.com/2018/07/04/type-type-yellow/