Page 222 - CITS - Welder - Trade Theory

WELDER - CITS

- Plates/sections of less thickness/size cannot be welded.
- Welding can be done only inside a factory/shop and not at sites.

- Soft metals and metals with low compressive strength cannot be welded.
- Only butt joint can be done.
- There is a burr surrounding the weld area.
Friction stir welding

Objectives : At the end of this lesson you shall be able to
• describe the principal of friction stir welding
• explain the application of friction stir welding
• explain the parameter of friction stir welding.

Principle of operation: Friction stir welding (FSW) is an innovative solid-state joining process which was invented
and patented by “The Welding Institute”, in 1991. During FSW, a welding tool, which consists of a shoulder and a
specially designed pin, is plunged into the plates to be welded, while rotating and advancing at a welding speed
along the joint line until the plates have been butted together.

The parts are clamped rigidly onto a backing bar in a manner that prevents the plates from being forced apart. v
The length of the pin is slightly less than the weld depth required and the tool shoulder is in full contact with the
work surface
Process parameters ¬ Welding speed (mm/min) ¬ Rotational speed (RPM) ¬ Axial force (kN) ¬ Geometry and
design of the welding tool ¬ Tool tilt angle ¬ Location of each material (AS, RS) when welding of dissimilar alloys
is applied,

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CITS : C G & M - Welder - Lesson 61-76