BRAZING

 Dip Brazing.
                    There are two methods of dip brazing: chemical bath and molten metal bath. In chemical bath dip brazing, the brazing fillermetal is preplaced and the assembly is immersed in a bath of molten salt, as shown in figure 6-10. The salt bath furnishes the heat necessary for brazing and usually provides the necessary protection from oxidation. The salt bath is contained in a metal or other suitable pot and heated. In molten metal bath dip brazing, the parts are immersed in a bath of molten brazing filler metal contained in a suitable pot. A cover of flux should be maintained over the molten bath to protect it from oxidation. Dip brazing is mainly used for joining small parts such as wires or narrow strips of metal. The ends of wires or parts must be held firmly together when removed from the bath until the brazing filler metal solidifies.

 Resistance Brazing.
                          The heat necessary for resistance brazing is obtained from the resistance to the flow of an electric current through the electrodes and the joint to be brazed. The parts of the joint are a part of the electrical current. Brazing is done by the use f a low-voltage, high-current transformer. The conductors or electrodes for this process are made of carbon, molybdenum, tungsten or steel. The parts to be brazed are held between two electrodes and the proper pressure and current are applied. Pressure should be maintained until the joint has solidified.

. Block Brazing.
                      In this process, heat is obtained from heated blocks applied to the part to be joined.

Flow Brazing.
                    In flow brazing, heat is obtained from molten, nonferrous metal poured over the joint until the brazing temperature is obtained


Infrared Brazing (IRB)
                           Infared brazing uses a high intensity quartz lamp as a heat source. The process is suited to the brazing of very thin materials and is normally not used on sheets thicker than 0.50 in. (1.27 cm). brazed are supported in a position which enables radiant energy to be focused on the joint. The assembly and the lamps can be placed in an evacuated or controlled atmosphere