Friction stud welding

I want to introduct something about .
Friction stud welding is a solid phase welding technique involving a stud, appurtenance or small pipe fitting being rotated at high speed while being forced against a substrate, generating heat by friction. The metal surfaces reach a temperature at which they flow plastically under pressure, surface impurities are expelled and a forged weld is formed.

A friction stud weld.
This technique is rather more costly than arc stud welding and is therefore used for special applications where arc welding may present problems, such as:
welding underwater
welding on live subsea pipelines to attach anodes
welding in explosive environments and zoned areas
welding materials that are difficult to join by fusion welding processes
friction plug welding
welding pipe fittings onto flat or curved surfaces
Portable equipment for friction stud welding is available for use on construction work sites, offshore, underwater and in workshops. These portable units are much lighter and smaller than the large static friction welding machines which are used, for example, in factories to weld engine components such as drive shafts.
Contents
1 Principle of operation
2 Advantages and disadvantages
3 Applications
3.1 Welding underwater
3.2 Welding on live subsea pipelines to attach anodes
3.3 Welding in explosive environments and zoned areas
3.4 Welding materials that are difficult to join by fusion welding processes
3.5 Friction plug welding
3.6 Welding pipe fittings onto flat or curved surfaces
4 References
5 External links
//
Principle of operation
A portable friction stud welding tool consists of a motor to rotate the stud at high speed and a piston to apply the necessary force to the stud. The equipment may be air or hydraulically powered. A clamping system is also required to hold the tool onto the work piece and to provide reaction to the force on the stud. The clamps used are typically magnetic or vacuum clamps for flat surfaces, chain or claw clamps for pipes and various mechanical clamps for welding onto I beams or other shapes.
The weld is made by rotating the stud at high speed and forcing it onto the substrate causing friction which heats the stud tip and substrate surface. Metal at the interface between the stud and the substrate flows plastically under pressure, removing impurities from the metal surfaces, and a solid phase weld is formed. The rotation of the stud is then stopped but the force on the stud is maintained for a few seconds. The maximum temperatures reached during welding are much lower than the melting point of the metals.
Advantages and disadvantages
Some notable advantages of the process are:
The relatively low temperature at which the weld is formed means that the process can be adapted for applications such as welding on live pipelines and in explosive environments.
The absence of an electric arc and a liquid phase in the metal avoids some of the potential problems encountered with arc welding such as contamination of the weld with hydrogen, nitrogen and oxygen.
The rapid weld cycle time (typically 5 to 10 seconds) and the method of weld formation result in a fine grain structure.
In the s welded condition the residual stresses are compressive which tend to result in good fatigue life. Studs can also be welded through epoxy paint coatings up to approximately 3 mm thickness.
The main disadvantages of this process are:
The process can only be used to weld relatively small components (such as studs, pipe nipples or plugs) which can be rotated at high speed, onto a work piece. The systems used are limited to studs up to typically 25 mm diameter, pipe nipples and appurtenances up to typically 60 mm diameter and plugs for filling holes up to typically 25 mm diameter (plug welding).
The system requires a rigid clamp to hold the welding tool on the work piece and withstand the force applied to the stud during welding. Although these clamps can be moved from one weld location to the next quite rapidly they are generally larger and more cumbersome than is the case with arc stud welding systems.
Applications
For the type of applications listed here it is especially important that the welding and operating procedures are fully tested and certified for both weld integrity and operational safety prior to use in production. Operators must be thoroughly trained and systems must be in place to ensure that the procedures are properly applied and risks properly assessed.
Welding underwater
When this process is used underwater, a shroud is fitted around the stud which prevents the weld from being cooled too rapidly by the surrounding water. The air powered systems can operate underwater to a depth of approximately 20m and are relatively simple for divers to...(and so on) To get More information , you can visit some products about kitchen waste baskets, dirt bike suzuki, . The products should be show more here!