How do you solder the brass plate?
Brass welding brass is a copper zinc alloy, because the boiling point of zinc is low, only 907 degrees, so the welding process is easy to evaporate, this becomes the biggest problem of brass welding. Under the influence of welding high temperature, the amount of evaporation of zinc is up to 40%, and the evaporation of zinc results in the decrease of mechanical properties and corrosion resistance of welded joints, and increases the sensitivity to stress corrosion. The evaporation of zinc was immediately oxidized to Zinc Oxide in the air, the formation of white smoke, which brings great difficulties to the operation, but also affects the health of the welder, welding brass place, we should strengthen the ventilation and other protective measures. The weldability of brass is poor, and the problems of blowhole, crack, zinc evaporation and oxidation occur during welding. In order to solve these problems, silicon welding wires are often used in welding, because silicon will form a dense film of silicon oxide on the surface of molten pool, which will hinder the evaporation and oxidation of zinc and prevent the invasion of hydrogen. After welding can be annealed at 470~560 degrees to eliminate stress and prevent "self cracking" phenomenon.
Welding parameters of manual tungsten argon arc welding brass are shown in table. Brass welding parameters of /mm thick plate material groove diameter tungsten /mm power type and polarity welding current /A argon flow TIG welding / (L/min) / C preheating temperature of ordinary brass 1.2 end with 3.2 DC 1857 warm-up Tin Brass 2 V 3.2 DC 1807 without preheating due to protection the effect of zinc evaporation damage of argon, so welding brass should be selected larger nozzle diameter and argon flow. Generally, no preheating is needed before welding. Only when the welding thickness is greater than 10mm and the joint with a large difference in the thickness of the welding edge shall be preheated. The latter only preheat the thicker part of the weldment.
Method of welding method used in the production of brass welding brass is SMAW and TIG welding, the following points: (1) the process of welding arc welding electrodes with bronze wire electrodes, such as ECuSn-B (T227), ECuAl-C (T237). The copper casting with low requirement for repairing welding can be made of pure copper core electrode, such as ECu (T107). The power supply adopts DC positive connection, and the angle of V type groove shall not be less than 60 degrees to 70 degrees. When the plate is thicker than 14mm, the surface of the weldment shall be carefully cleaned before welding to remove all the oil impurities which will produce hydrogen. The operation shall be done with short arc welding. The electrode shall not move transversely or back and forth only along the straight line of the weld line. Welding speed should be less than 0.2 ~ 0.3m/min. In multilayer welding, the oxide film and slag between the layers shall be removed. The fluidity of liquid copper brass, so the best solution pool in a horizontal position, if the bath must be tilted, it should not be greater than 15 degrees angle (2) argon arc welding TIG welding, welding wire with tin brass wire HSCuZ-1 (HS221), iron and brass wire HSCuZn-2 (HS222), yellow silicon brazing wire HSCuZn-4 (HS224).
