Brass welding

Brass welding methods are: gas welding, carbon arc welding, manual arc welding and argon arc welding. (1) brass gas welding. Because the flame temperature of gas welding is low, the evaporation of brass is less than that of electric welding when welding. Therefore, the most commonly used method of gas welding is brass welding. The welding wire of brass gas welding has: wire 221, silk 222 and silk 224. These wires contain silicon, tin, iron and other elements, which can prevent and reduce the evaporation and loss of zinc in the molten pool. It is beneficial to ensure the weld performance and prevent the formation of gas holes. Commonly used fluxes for gas welding brass are two kinds of solid powder and gas flux. The flux is composed of boric acid methyl ester and methanol, and flux is 301. (2) manual arc welding of brass. In addition to using copper 227 and copper 237, welding brass can also be made of self-made welding rod. When the arc welding is done, direct current should be used to connect the electrode to the negative electrode. The surface of the weldment should be carefully cleaned up. The groove angle should not be less than 60-70. The welding piece should be preheated at 150-250 degrees to improve the weld shape. During operation, short arc should be used for welding without transverse and front swinging, only for straight line movement, and high welding speed. Contact with brass, such as seawater and ammonia, must be annealed after welding to eliminate welding. Power. (3) manual argon arc welding of brass. Brass manual argon arc welding can be made of standard brass welding wire: Silk 221, silk 222 and silk 224. Welding can be connected by direct current or by alternating current. When AC welding is used, zinc evaporation is lighter than DC direct connection. Usually, it is not preheated before welding. Only when the thickness difference is relatively large, is it preheated. The welding speed should be as fast as possible. After welding, the weldment should be heated at 300-400 C for annealing treatment to eliminate welding stress, so as to prevent cracks in the weldment. (4) brass carbon arc welding. When the carbon arc welding of brass is made of wire 221, silk 222 and silk 224 according to the composition of the base metal, it can also be welded with self made brass welding wire. Gas flux 301 can be used as flux for welding. Welding should be short arc operation to reduce zinc evaporation and burnout. In recent years, more and more construction of copper and copper alloys has been carried out by using MIG method. Especially for 3mm aluminum bronze, silicon bronze and white copper with thickness of more than 3mm, it is better to choose the method of welding. The thickness of 3~14mm or >14mm copper and copper alloy is almost always selected by MIG welding, because of high deposition efficiency, large melting depth and fast welding speed (generally 3~4 times TIG welding), so as to achieve high efficiency, high quality and low cost economic benefits. Copper materials should meet the requirements of preheating temperature before welding (pure copper at 400~600 C, Cu alloy 200~300 C). The welding wire is fully similar to that of base metal, and the purity of argon is more than 99.98%.