Home > News > Content

Dayang Welding Materials Lecture Hall | Welding Method Of Flame Brazing

Nov 18, 2019

Flame brazing is a brazing process using a flame formed by combusting a vaporized product of a combustible gas or a liquid fuel with oxygen or air. It is divided into flame brazing and flame soldering.
  This welding method has wide application, high versatility, simple process, easy to master operation technology, and easy to realize automatic operation. The initial investment of the equipment is low, the types of combustion gases are many, the source is convenient and reliable, and the flame is brazed in the air. Finished, no protective gas is required, usually requires the use of flux; the choice of solder is wide, from low-temperature silver-based solder to high-temperature nickel and copper-based solder, and there is almost no requirement for the shape of the solder. Solder in the form of filaments, flakes, preforms or pastes can be used in flame brazing.

  However, because the flame brazing is done in an oxidizing environment, the surface of the joint after brazing has flux residue and hot scale. Moreover, the heating temperature is difficult to master during manual operation, so workers are required to have a higher technical level. It is also not suitable for brazing metals such as titanium and zirconium which are easily oxidized. In addition, flame brazing is a local heating process that may cause stress or deformation in the base metal.
  The advantages and disadvantages of flame brazing are outstanding, and overall, they have more advantages. If you have a pair of eye-catching eyes, it is not difficult to find that this method is used in the welding of small and medium parts such as bicycles, electric frames and aluminum kettle mouths in our lives.
  If you want to use flame brazing to weld the workpiece, you can refer to the following procedure!
  Before brazing, the surface of the workpiece is first cleaned. The flame is then adjusted to heat in the brazed area. When brazing, maintain a uniform temperature, especially the temperature on the bonding surface should reach the brazing temperature uniformly, so it should be maintained at the brazing temperature for a period of time as much as possible to complete the gap of the brazing material to the joint. Inflow and gas evolution. To achieve this, the torch is constantly oscillating during manual brazing; in automated operation, the workpiece is swung and rotated as it passes through the heated zone, or the flame is moved around the workpiece.

  Feeding brazing materials are commonly used in manual flame brazing operations, and prefabricated brazing fluxes or fluxes can be used in automated flame brazing operations. When the brazing wire is manually sent to the joint, the brazing wire is first immersed in the flux, and then the brazing filler metal is applied to the joint, and the action can be completed multiple times during the heating of the workpiece, even in the addition. After the brazing material, if there is a phenomenon that hinders the flow of the brazing material, it can also be compensated by adding a flux, and at the same time controlling the heat to cause the molten brazing material to flow through the joint. After brazing is completed, the joint must be cooled below the solidus line of the solder in a static state to prevent cracking of the joint.