Brass Welding Technology

Brass welding methods inculde gas welding, carbon arc welding, manual arc welding and argon arc welding.

1. Gas welding of brass

Because of the low flame temperature of gas welding, the evaporation of zinc in brass is less than that in electric welding, so gas welding is the most commonly used method in brass welding.

The welding wires used in brass gas welding are wire 221, wire 222 and wire 224. These wires contain silicon, tin, iron and other elements, which can prevent and reduce the evaporation and burning loss of zinc in the molten pool, and help to ensure the performance of the weld and prevent porosity. There are two kinds of fluxes commonly used in brass gas welding: solid powder and gas flux. Gas flux are composed of methyl borate and methanol, and fluxes such as gas flux 301.

2. Manual arc welding of brass

In addition to using copper 227 and copper 237, welding brass can also use self-made welding rod.

When the arc welding is done, DC positive connection should be used, that is to connect the electrode to the negative electrode. The surface of the welds should be carefully cleaned before welding. The groove angle should not be less than 60~70°. To improve the weld shape, the weldment should be preheated at 150~250℃ C. During operation, short arc should be used for welding without transverse and front swinging, only for straight line movement, and high welding speed. Brass weldment in contact with seawater, ammonia and other corrosive media must be annealed after welding to eliminate welding stress.

3. Manual argon arc welding of brass

Standard brass wire 221, wire 222 and wire 224 can be used for manual argon arc welding of brass, or the same composition as the base metal can be used as filler material.

Welding can be connected by direct current or by alternating current. When AC welding is applied, zinc evaporates more slowly than DC. Usually, it is not preheated before welding. Only when the thickness difference is relatively large, it needs to be preheated. Welding speed should be as fast as possible.

After welding, the weldment should be annealed at 300 ~ 400 C to eliminate welding stress and prevent cracks in the process of using.

4. Brass carbon arc welding

In carbon arc welding of brass, wire 221, wire 222, wire 224 and other welding wires can be selected according to the composition of base metal, and self-made brass welding wires can also be used. Welding can use gas agent 301 as Flux. Welding should be operated with short arc to reduce the evaporation and burn loss of zinc.