Types and characteristics of copper and copper alloys
Copper is one of the representative nonferrous metal materials necessary for industry and daily life, and there are many types. It has a long history of practical use, and was unearthed in an Egyptian tomb as early as 400 BC, making it a familiar material used for a long time in countries around the world. Many of the copper and copper alloys that are now in practical use are incomparable in type and performance compared to those at that time, but the basic properties of copper have not changed much. It is the properties that iron does not have that make copper such a useful material.
Properties of Copper and Copper Alloys
The best properties of copper are its processability, electrical conductivity, and thermal conductivity. As can be seen from the example of copper wire, this material has the highest electrical conductivity and thermal conductivity after silver, and is used in many electrical parts, motors, wiring, and circuit boards.
It is said that one of the reasons why copper has been widely used since ancient times is that it is easy to process. It is a representative metal with excellent ductility and is easy to perform plastic processing such as rolling and extrusion. Copper also has a beautiful finished surface and comes in a variety of colors, which is part of the reason why we see copper everywhere.
In addition, it has excellent hot forging properties, which is suitable for processing complex products. It also has excellent spring properties and uses copper alloys with high fatigue strength such as beryllium copper and phosphor bronze. Unlike steel materials, its structure does not break even at extremely low temperatures, making it a material with excellent low-temperature brittleness. It also has excellent corrosion resistance, and since it is a noble metal, it is said to be resistant to corrosion caused by contact.
Generally speaking, their use temperature is below 200°C, and even if they are excellent in heat resistance, the maximum use temperature is around 250°C to 300°C. There are some copper alloys, such as white copper, that can be used at temperatures above 400°C. On the other hand, it does not become brittle at extremely low temperatures, so it can be used without any problems.
Various types of copper materials
By type, copper includes pure copper, brass, bronze, white copper, nickel silver, white copper, and beryllium copper. In addition to pure copper, it is a copper alloy made of copper with zinc, lead, tin, aluminum, nickel, etc. alone or in combination.
In addition, depending on the manufacturing method, copper is divided into two types: rolled copper products and cast products. In fact, nearly 90% of copper products are considered rolled copper products. Brass is also the most commonly used material among copper alloys, and pure copper and brass are said to occupy the majority of copper demand.
Copper Symbols
The notation symbol (copper elongation) of copper materials also matches these classifications. Copper and copper alloys such as C1020 (oxygen-free copper) are represented by the letter C and four digits in the JIS standard. The 1000 series of C1 is pure copper or alloys containing a large amount of copper, and is a category that also includes C17 beryllium copper and C19 titanium copper. The 2000 series such as C2801, C2700, etc. are copper-zinc Cu-Zn copper alloys such as brass and red bronze, and the 3000 series such as C3604 are free-cutting brass, and Pb is added to improve machinability. The 4000 series is Cu-Zn based naval brass with Sn (tin) added, the C5000 series is phosphor bronze (Cu-Sn-P alloy), of which C5191 is a typical example, the 6000 series such as C6161, C6191 are aluminum bronze, brass for instrument valves, high-strength brass, and the 7000 series such as C7351 have nickel silver and white copper (copper nickel alloy). We will briefly introduce the characteristics of each copper alloy on the page of each copper alloy.
Typical physical properties of copper
Melting point about 1084℃
Boiling point about 2360℃
Specific heat (20℃) 385J/kg·℃
Density 8.96g/cm3 (20℃)
Longitudinal elastic modulus (Young's modulus) 117.7kN/mm2
Thermal expansion coefficient (20-100℃) 16.8x10-6 / ℃
Electrical conductivity 100%IACS
Resistivity (20℃) 1.7241μΩ·cm
Resistance temperature coefficient (20℃) 0.00397/℃
Magnetic susceptibility -0.080x10^-6 cgs unit/gram
