Friction stir welding (FSW) is a solid-state joining process invented in 1991 that uses a non-consumable tool to join materials without melting them, resulting in high-strength welds at lower costs. The process generates heat through friction, allowing the workpieces to be softened below their melting point, and offers advantages such as reduced distortion and improved mechanical properties, while having some disadvantages like slower traverse rates. FSW is widely used in industries such as shipbuilding, aerospace, and automotive for various applications.

1. Friction Stir
Welding (FSW)

2. What is stir welding ?
•Stir welding is a solid state joining
process that uses a non consumable
toot to joint two facing work pieces
without melting the workpiece
material.

3. Introduction
• FSW was invented by Wayne Thomas in 1991.
• It is low energy input, capable of producing very
high strength welds in wide range of materials at
lower cost.
• FSW process takes place in the solid phase
below the melting point of the materials to be
joined.
• FSW welding belongs to plastic welding
category. Due to,
• Heated to plastic state
• Pressure required

4. Working principle
• Heat is generated by friction between rotating tool and the
workpiece material which leads to soften reign near the SFW
tool.

5. Process
• A cylindrical tool with a profiled threaded probe
is used
• The tool which rotated at constant speed and is
then placed between the work piece materials.
• The metallic parts should be clamped properly
so the joint faces cannot be forced apart by the
process.

6. Microstructure Analysis
• There are three main regions,
• Heat affected zone
• Thermomechanically affected zone
• Stir zone

7. Tool parameters
• Tool : HSS (High Speed Steel)
• Tool pin profile : Hexagonal
• Tool dimensions :
• Tool length = 80 mm
• Tool diameter = 18 mm
• Tool pin diameter = 6 mm
• Tool pin length = 5.8 mm
• Coating material : TiAlN (PVD – Physical Vapor Deposition )
• Coating thickness = 4mm
• Coating done in vaccum at low pressure in the temperature
range of 450-900 c

8. Welding machine and tools

9. Comparison with other
welding
•Reduced distortion
•Reduced defect rate
•Simplifies dissimilar alloy welding
•Eliminate consumables
•Reduces health and hazard and no
weld pool

10. Advantages
• Good mechanical properties as in weld condition
• Improved safety due to absence of toxic fumes
• No consumables
• Easily automated on simple milling machines
• Can operate on all positons
• Low environment impact
• High superior weld strength
• Generally good weld appearance

11. Disadvantages
• Exit hole left when tool is withdrawn.
• Large down forces required with heavy
duty clamping necessary to hold the plates
to weld.
• Slower traverse rate than fusion welding
• Less flexible than manual and arc
processes

12. Applications
• Shipbuilding and offshore :- hulls and
superstructure, helicopter landing platforms
• Aerospace :- wings , fuselages , empennages
• Automotive :- Aluminum engine cradles and
suspension struts
• Railway rolling stock :- Railway tankers and
goods wagons
• Fabrications and robotics
• Personal computers :- components of computer