Copper, brass, red copper (also known as "copper"), and bronze (blue-gray or gray-yellow) are distinguished by color.

Among them, white copper and brass are easy to distinguish; red copper is pure copper (impurity <1%), and bronze (about 5% of other alloy components) is slightly difficult to distinguish. When not oxidized, the red copper is brighter than bronze, and the bronze is slightly cyan or yellow. After oxidation, the red copper becomes black, and the bronze is turquoise (a harmful oxidation of water) or chocolate.

的 Classification and welding characteristics of copper and copper alloys

(1) Pure copper: Pure copper is often called red copper. It has good electrical conductivity, thermal conductivity and corrosion resistance. Pure copper is represented by the letters + T}} (copper), such as Tl, T2, T3 and so on. The content of oxygen is extremely low, and pure copper not more than 0.01% is called oxygen-free copper, which is represented by TU (copper-free), such as TU1, TU2, and so on.

(2) Brass: A copper alloy with zinc as the main alloying element is called brass. Brass is represented by + H; (yellow) such as H80, H70, H68 and so on.

(3) Bronze: Copper and tin alloys were previously called bronze, but copper alloys other than brass are now called bronze. Commonly used are tin bronze, aluminum bronze and sensitive bronze. Bronze is represented by "Q, '(blue).

焊接 The welding characteristics of copper and copper alloy are:

(1) Difficult to fuse and deform easily

(2) easy to generate thermal cracks

(3) easy to produce pores

Copper and copper alloy welding mainly adopts gas welding, inert gas shielded welding, submerged arc welding, brazing and other methods.

Copper and copper alloys have good thermal conductivity, so they should generally be preheated before welding, and welded with high wire energy. Tungsten hydrogen arc welding adopts DC positive connection. For gas welding, copper uses a neutral flame or a weak carbonized flame, and brass uses a weakly oxidized flame to prevent evaporation of zinc.