Welding is the process of joining metal parts with fusible alloy (solder). The melting point of solder is lower than that of the material to be welded, so that the component will be melted, through the contact between molecules on its surface to end the welding. Welding can be divided into soft welding hard welding, soft welding temperature is lower than 450 ℃, hard welding is higher than 450 ℃. Hard welding is usually used for silver, gold, steel, copper other metals. Its welding point is much stronger than soft welding, its shear strength is 20 ~ 30 times of that of soft welding.
The term welding is usually used in both of the above thermal connections, since in both cases molten solder is written into a thin slit on the clean close solid metal surface of the two devices to be installed. Welding ensures the continuity of the metal. On the one hand, two kinds of metals are connected with each other through bolt connection physical adhesion, showing a strong metal whole, but the connection is discontinuous. Sometimes, if there is oxide insulation film on the surface of metal, they are in physical contact with each other.
Another defect of mechanical connection compared with welding is the addition of resistance due to the continuous oxidation of the contact surface. In addition, vibration other mechanical shocks can also loosen the joint. Welding eliminates these problems, the welding position does move relative, the contact surface does oxidize, the continuous conductive method can be adhered to.
Welding is the fusion process between two metals. In the molten state, soldering tin will dissolve some metal in contact with it, the surface of the metal to be welded often has a thin layer of oxide film that can be dissolved by solder. Flux is used to remove the oxide film. For example, the change of temperature, wetting, vibration, etc., a bad welding point can cause some out of control of the system.
There are countless welding points in the equipment, the reliability of these welding points should be higher than the equipment itself. The research on this aspect has led to the addition of knowledge of materials their properties, many developments have been made in the available welding processes. Welding technology is an accompanying technology. With the development of electronic industry, useful packaging technology small components are constantly produced. Welding technology will continue to expand to meet the needs of electronic industry environmental issues.
