Welding is the process of using various fusible alloys (solder) to connect metal parts. The melting point of solder is lower than that of the material being welded, so that the component will be welded through the contact between the molecules through its surface without being melted.
Welding can be divided into soft welding and hard welding, soft welding temperature less than 450 ℃, hard welding is higher than 450 ℃. Hard welding is usually used in silver, gold, steel, copper and other metals, the welding point is much stronger than soft welding, shear strength of soft welding 20~30 times. The term welding is usually used for both of the above two types of heat connections, as both cases are written into the thin slits of the clean and close solid metal surface of the two devices to be installed.
Welding ensures continuity of the metal. The two metals are connected by bolting or physical attachment to each other, showing a robust metal whole.