Understand the difference between brass, phosphor bronze and red copper

Pure copper is a purple-red metal, commonly known as "red copper", "red copper" or "red copper". Pure copper is ductile. Pure copper the size of a drop of water can be drawn into filaments up to two kilometers long, or rolled into almost transparent foils larger than a bed. The most valuable property of pure copper is that its electrical conductivity is very good, second only to silver among all metals, so it has become the "protagonist" of the electrical industry.

Pure copper is much more widely used than pure iron, and 50% of copper is electrolytically purified to pure copper every year for the electrical industry. The pure copper mentioned here is indeed very pure, with a copper content of more than 99.95%. Very small amounts of impurities, especially phosphorus, arsenic, aluminum, etc., can greatly reduce the conductivity of copper. Oxygen in copper (a small amount of oxygen is easily mixed in copper smelting) has a great influence on electrical conductivity, so copper used in the electrical industry must generally be oxygen-free copper. In addition, impurities such as lead, antimony, and bismuth will make the crystals of copper unable to combine together, causing hot brittleness and affecting the processing of pure copper.

This high-purity pure copper is generally refined by electrolysis: using impure copper (that is, blister copper) as the anode, pure copper as the cathode, and copper sulfate solution as the electrolyte. When the current passes through, the impure copper on the anode gradually melts, and the pure copper gradually precipitates on the cathode. The copper obtained in this way; the purity can reach 99.99%.

Red copper is a relatively pure copper, which can generally be regarded as pure copper, with good electrical conductivity and plasticity, but poor strength and hardness.

Properties and uses of brass

Brass is a kind of copper containing other alloy components. Its price is cheaper than that of red copper. Its conductivity and plasticity are slightly worse than that of red copper, but its strength and hardness are higher.

Brass is an alloy of copper and zinc. The simplest brass is a copper-zinc binary alloy, called simple brass or ordinary brass, and brass with different mechanical properties can be obtained by changing the zinc content in brass. The higher the zinc content in brass, the higher the strength and the lower the plasticity. The zinc content of brass used in the industry does not exceed 45%. No matter how high the zinc content is, it will cause brittleness and deteriorate the alloy properties.

Adding 1% tin to brass can significantly improve the resistance of brass to seawater and marine atmospheric corrosion, so it is called "navy brass". Tin can improve the machinability of brass. Lead brass is what we usually call easy-cutting national standard copper. The main purpose of adding lead is to improve machinability and wear resistance, and lead has little effect on the strength of brass. Engraved copper is also a type of lead brass. Most brasses have good color, workability, ductility, and are easy to electroplate or paint.

In industry and civil use, different materials are selected according to different use characteristics. Such as wire, the requirement is softer, copper is better. If it is used as a connecting piece, the place where the screw is attached is mostly made of brass.

Properties and uses of bronze

Originally refers to copper-tin alloys, and later copper alloys except brass and cupronickel are called bronze, and the name of the first main added element is often prefixed to the name of bronze. Tin bronze has good casting performance, anti-friction performance and good mechanical performance, and is suitable for manufacturing bearings, worm gears, gears, etc. Lead bronze is a widely used bearing material for modern engines and grinders. Aluminum bronze has high strength, good wear resistance and corrosion resistance, and is used for casting high-load gears, bushings, marine propellers, etc. Beryllium bronze and phosphor bronze have high elastic limit and good electrical conductivity, and are suitable for the manufacture of precision springs and electrical contact elements. Beryllium bronze is also used to make non-sparking tools used in coal mines and oil depots.

Properties and uses of white copper

A copper alloy with nickel as the main additive element. The copper-nickel binary alloy is called ordinary cupronickel; the cupronickel alloy with manganese, iron, zinc, aluminum and other elements is called complex cupronickel. Industrial cupronickel is divided into two categories: structural cupronickel and electrical cupronickel. The characteristics of structural cupronickel are good mechanical properties and corrosion resistance, and beautiful color. This cupronickel is widely used in the manufacture of precision machinery, chemical machinery and ship components. Electrical cupronickel generally has good thermoelectric properties. Manganin, constantan and test copper are manganese cupronickel with different manganese content, which are used in the manufacture of precision electrical instruments, varistors, precision resistors, strain gauges, thermocouples, etc.

How to distinguish between copper, brass, bronze and cupronickel

White copper, brass, red copper (also known as "red copper"), and bronze (blue-gray or gray-yellow) are distinguished by color, among which white copper and brass are very easy to distinguish; red copper is pure copper (impurity<1%) ) and bronze (about 5% of other alloy components) are slightly difficult to distinguish. When it is not oxidized, the color of red copper is brighter than that of bronze, and the bronze is slightly cyan or yellowish; after oxidation, the red copper becomes black, and the bronze is turquoise (harmful oxidation of water) or chocolate color.