Classification of welding methods
With the continuous development of production and science and technology, there are many types of metal welding methods. If they are distinguished according to the characteristics of the welding process, they can be summarized into three categories: (classification family method) welding, pressure welding, and brazing.
1) Fusion welding-definition: In the case of not applying pressure, the welding method of melting the base metal at the place to be welded to form a weld is called fusion welding. Arc welding: melting electrode (electrode arc welding, submerged arc welding, molten electrode gas shielded welding, screw melting pole welding) non-melting electrode (tungsten arc welding, plasma arc welding, carbon arc welding, atomic hydrogen non-melting Electrode welding, gas welding, oxygen hydrogen, oxyacetylene, air acetylene, thermite welding, electroslag welding, electron beam welding, laser welding). The common feature of this type of welding method is that the joint of the weldment and the filler metal material (sometimes without the filler metal material) are melted by a local heat source, and they are fused with each other without pressure, and after cooling and solidification, a strong joint is formed. Both electroslag welding belong to this category.
2) Pressure welding-definition: During the welding process, pressure (heated or not) must be applied to the weldment. The method of completing the welding is called pressure welding. Resistance welding (spot welding, seam welding, projection welding, butt welding, high frequency welding); cold pressure welding (ultrasonic welding, explosive welding, forging welding, diffusion welding, friction welding, gas pressure welding). The common feature of this type of welding method is that a certain pressure is applied to the weldment regardless of whether it is heated or not, so that the two bonding surfaces are in close contact to produce a bonding effect, so that the two weldments are connected together. Contact welding and friction welding belong to this category. class..
3) Brazing-Definition: Use a metal material with a lower melting point than the base material as the brazing filler metal, heat the weldment and brazing filler metal to higher than the melting point of the brazing filler metal and lower than the melting temperature of the base metal, and use the liquid brazing filler metal to wet the base metal The welding method that fills the joint gap and diffuses with the base material to connect the weldment is called brazing (flame, induction, furnace, immersion, electron beam, infrared, etc.). Brazing and fusion welding are similar, but there are essential differences. It uses a metal material with a lower melting point than the base material as the brazing filler metal, and heats the weldment and brazing filler metal to a temperature higher than the melting point of the brazing filler metal but lower than the melting point of the base metal. The method of using liquid solder to wet the base material, filling the joint gap and mutual diffusion with the base material to realize the connection of the weldment.
