Copper belongs to heavy metals. Its specific weight is about 8.93 kg / cm³, and the melting temperature is 1083 ° C. The copper does not have any properties of allotropic modifications. The mechanical properties of the copper are highly dependent on the state or possible previous mechanical or thermal processing. Copper is a very plastic material that can be processed by deformation, both in cold and hot conditions. For welding, copper is not the most suitable, as it creates difficulties in the required rapid heat removal. During gas welding, due to the high propensity of gas absorption, increased porosity and brittleness may occur.
The mechanical properties of the copper are highly dependent on the state or possible previous mechanical or thermal processing. Copper is a very plastic material that can be processed by deformation, both in cold and hot conditions. For welding, copper is not the most suitable because it creates difficulties in the required rapid heat removal. During gas welding, due to the high propensity of gas absorption, increased porosity and brittleness may occur.
Basic properties of copper
- reddish colors,
- relatively high volume mass ρ = 8.9 g / cm3
- melts at 10830 C
- An excellent conductor of electric current, the best among non-precious metals, but its primers considerably reduce conductivity.ž
- good heat conductor.
- Corrosive is air-resistant because it is created on the surface of green patina (CuO3xCu (OH) 2) which is dense and protects it from further corrosion.
- Copper is a material of low tensile strength and is very elastic.
- The copper has a cubic surface-centering grid and a structure of polyhedron crystals
Wide application in electrical conductors for making conductors. Pure copper does not have much use in aerial constructions, but its alloys are used. It is well-alloyed with zinc, aluminum, lead, tin, and beryllium. Copper alloys have a much better tensile strength than pure copper, but they are so weak that they are more heat insulators.
- oxidized on pure, humid or salty air. With CO 2 there is a patina, which spreads to decay,
- it is scorched by sea and ordinary water, but not distilled,
- it is destroyed by ammonia and sulfur, so rubber insulation can not be placed directly on it,
- it dissolves in nitric and sulfuric acid
Copper alloys can be classified according to the way of making, the purpose, the number of the main alloying elements, the nature of the main alloying elements
a) Zinc alloys - mesins:
- two-component Cu-Zn alloys (conventional brass)
- special Cu-Zn alloy special alloys
- three-component Cu-Ni-Zn alloys (new silver :)
- three-component alloy Cu-Zn-Sn (red cast). These are alloys representing a transition from brass to bronze.
b) Copper alloys without zinc - bronze, are two, three and complex Cu-alloys:
- Calyx bronze - Cu-Sn alloys
- Aluminum bronze - Cu-Al alloys
- Nickel bronze - Cu-Ni alloys
- Lead and lead-acid bronze - Cu-Pb and Cu-Sn-Pb alloys
- Bronze silicon - Cu-Si alloys
- Beryllium bronze
- Manganese bronze
c) Copper alloys for soldering and welding:
- Mesingani lem
- Silver Lime
The most famous copper alloys are those with zinc-alloying and alloys in which zinc is not the main alloying element (bronze).
Standard Copper Types:
|SE-Cu 2.070||~C 10 300||~Cu-c1||~Cu-OF||C 103|
|SW-Cu 2.076||Cu-DLP||~C 12 000||~Cu-b2||~Cu-DLP||C 106||~M1R|
|SF-Cu 2.090||Cu-DHP||~C 12 000||~Cu-b1||~Cu-DHP||C 106|
The cold treatment of hardness and the tensile strength of the copper increase considerably. Tensile strength depends on the chemical composition, thermal and mechanical processing:
|Condition||Tensile strength N / mm2||Extension%||Hardness HB|
|soft||210 … 250||> 38||40 … 60|
|half-hard||250 … 300||> 10||60 … 90|
|hard||> 300||> 6||> 90|
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Brass is basically two-component copper (Cu) and zinc (Zn) alloys. In order to improve the properties of brass such as workability and corrosion resistance, other chemical elements are added in smaller quantities, thereby obtaining "special meshes".
Bronze refers to the alloy of copper and tin. However, more broadly, it does not have to be a double alloy or a tin must be an alloying element (therefore, in addition to tin, there are also aluminum, lead, manganese and other bronze.