SOLID PHASE WELDING
31 марта, 2014 
Oleg Maloletnikov This group of welding processes uses pressure and heat (below the melting temperature) to produce coalescence between the pieces to be joined without the use of filler metal. The processes under this category include: Diffusion Bonding, Cold Welding, Explosive Welding, Friction Welding, High Frequency Pressure Welding, Forge Welding, Hammer Welding, Ultrasonic Welding, etc. The important ones will now be discussed.
2.4.1 Friction Welding
Friction heat between two sliding/rotating surfaces is employed in this process to form a joint. The principle of working of the process is shown in Fig. 2.16. The pieces to be joined are clamped in chucks. One chuck rotates against a stationary one. Pressure is used to generate enough heat to reach a bonding temperature within a few seconds. At this stage the rotation is stopped and pressure is retained or increased to complete the weld. To accomodate awkward or very long parts, an intermediate slug or disc is rotated in between the sections to be joined.
|
Force
|
|
Start |
|
|
|
Fig. 2.16 Friction welding (A) Equipment (B) Stages 2.4.2 High Frequency Pressure Welding This process differs from H. F. resistance welding in that the current is induced in the surface layer by a coil wound around the workpiece. This causes surface layer to be heated. Weld is formed by a forging action of the joint (Fig. 2.17). It is used in the manufacture of tubes. The process is also termed as H. F. Induction Welding. |
|
(B) |
Force
Fig. 2.17(a) Using a high-frequency current to heat the interface in pressure welding
|
|
|
Induction |
|
— Impeder |
|
Fig. 2.17(b) Sketch of high-frequency pressure welding |
Опубликовано в Introduction to Welding Technology