Brazing is the use of metal material that is lower than the melting point of the base material as brazing material, the welding parts and brazing material is heated to a higher melting point than the solder, lower than the melting temperature of the parent material, the use of liquid solder wetting masterbatch, filling the joint clearance and with the parent material diffusion to achieve the Brazing deformation small, smooth and beautiful joints, suitable for welding precision, complex and composed of different materials components, such as honeycomb structure plate, turbine blades, carbide tools and printed circuit boards. Brazing before the workpiece must be meticulous processing and strict cleaning, remove oil and too thick oxide film, to ensure that the interface assembly gap. Clearance is generally required between 0.01 ~ 0.1 mm.
The first is the smooth surface of the joint, good gas tightness, shape and size stability, welding pieces of the organization and performance change little, can connect the same or not the same metal and some non-metallic. Brazing, the workpiece can also be used to heat the whole, welding a number of welds, improve productivity. However, the strength of brazed joints is lower, and the joint strength is improved by increasing lap length. In addition, the preparation work before brazing is higher.Brazing Alloy
Second, the solder melts and the welding parts do not melt. In order to make the brazing part firmly connected and enhance the adhesion of the solder, brazing should be used to remove the oxide from the solder and the surface of the solder. Hard solder (such as copper base, silver, aluminum base, nickel base, etc.), with high strength, can be connected to bear the load of the parts, application is more extensive, such as cemented carbide tools, bicycle frame. Soft solder (such as tin, lead, bismuth, etc.), welding strength is low, mainly used for welding not withstanding load but require good sealing, such as containers, instrumentation components.Brazing Alloy
Brazing adopts alloy with a melting point lower than the base material as brazing material, and the solder melts when heated, and is filled and kept in the joint gap by wetting action and capillary action, while the base material is in solid state, depending on the diffusion between the liquid brazing material and the solid parent material to form a brazing head. Brazing has little effect on physical and chemical properties of the base material, welding stress and deformation is small, dissimilar metal with different welding performance, can finish many welds at the same time, the joint appearance is neat, the equipment is simple and the production investment is small. However, the strength of brazed joints is low and the heat resistance is poor.Brazing Alloy