Classification and application of welding technology methods
Source：http://www.jmzkkj.comRelease Time：2018-06-02
The welding technology is mainly applied to the metal base metal. Commonly used arc welding, argon arc welding, CO2 protection welding, oxygen-acetylene welding, laser welding, electroslag pressure welding and many other non-metallic materials such as plastics can also be welded. There are more than 40 kinds of metal welding methods, mainly divided into three categories of welding, pressure welding and brazing.
Welding is a method in which the workpiece interface is heated to a molten state during welding, and welding is completed without applying pressure. During welding, the heat source rapidly heats and melts the interfaces of the two workpieces to be welded to form a molten pool. The molten pool moves forward along with the heat source, forming a continuous weld seam after cooling and connecting the two parts together.
In the welding process, if the atmosphere is in direct contact with a high temperature molten pool, oxygen in the atmosphere will oxidize metals and various alloying elements. Nitrogen in the atmosphere, water vapor, etc. enter the molten pool, and defects such as pores, inclusions, and cracks are formed in the weld during subsequent cooling, which deteriorates the quality and performance of the weld. The
Pressure welding is under pressure conditions, so that the two workpieces in the solid state to achieve inter-atomic bonding, also known as solid-state welding. The commonly used pressure welding process is resistance butt welding. When the current passes through the connection ends of the two workpieces, the temperature rises due to the large resistance. When heated to the plastic state, the connection is integrated under the axial pressure.
A common feature of various pressure welding methods is the application of pressure during the welding process without the addition of filler material. Most pressure welding methods such as diffusion welding, high frequency welding, cold pressure welding, etc. have no melting process, and thus there is no problem of burning of the beneficial alloy elements such as welding, and the intrusion of harmful elements into the weld, thereby simplifying the welding process, and also Improved welding safety and hygiene conditions. At the same time, the heat affected zone is small because the heating temperature is lower than the fusion welding and the heating time is short. Many materials that are difficult to weld by fusion welding can often be pressure welded into high-quality joints with the same strength as the base metal.
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