How to Distinguish Brass, Copper, and Phosphor Tin Bronze in Socket Switch Material?

These three types of copper products have different characteristics.

The distinguishing methods are as follows:

The First Type, Through Chemical Methods

Brass used in sockets generally contains copper content between 58-65%, with the rest being zinc. Brass is an alloy composed of copper and zinc. When the zinc content is less than 35%, zinc dissolves in copper, called single-phase brass. Its characteristic is good plasticity, suitable for cold and hot pressure processing. When the zinc content is between 36% and 46%, it becomes dual-phase brass, with decreased plasticity and increased tensile strength, only suitable for hot pressure processing. If the mass fraction of zinc continues to increase, the tensile strength decreases and it becomes of no use. The problem with brass is that it has a higher resistivity.

Pure copper, also known as red copper, generally contains over 99% copper. Phosphorus tin bronze contains about 94% copper and about 6% tin. Phosphor bronze (1.3-10% Sn, 0.1-0.3% P) is also widely used as elastic electrical contact material. Phosphor bronze has an ultra-fine grain structure, which can be obtained through special processing or micro-alloying. However, phosphor bronze cannot be used in conditions of high stress at temperatures exceeding 107 degrees, nor can it be used in a salty atmosphere.

In addition, low-lead brass (0.3-0.8% Pb) is used for pin-type electrical contacts.

Beryllium bronze (0.1-2.0% Be) has excellent mechanical properties, as well as electrical and thermal conductivity. It also has good wear resistance and corrosion resistance. However, beryllium bronze is rarely used in distribution sockets.

The Second Type, Through Appearance Judgement

Brass material has a light yellow color (some have outer electroplating, which needs to be polished off), red copper is purple-red, and the color is the darkest. Tin phosphor bronze has a color similar to red copper and is brighter in color.

The Third Type, Through Strength Judgement

Generally, red copper is the softest, easily deformed and not easily restored. Brass is slightly stronger than red copper and can recover slightly after deformation. Tin phosphor bronze has good elasticity and bounces back well after deformation.

Generally, brass is used for the socket heads. Inside the power strip, the long, plate-like component is generally made of tin phosphor bronze. There are also replacements with red copper, but they have a shorter service life and may affect the lifespan of the socket.