This document describes an experimental investigation of friction stir welding (FSW) process parameters and their effects on axial force generation. It outlines the design of the welding fixture and load cell used to measure axial forces. Experiments varied the rotational tool speed at three levels (800, 1000, 1200 rpm) and tool pin design with three angles (90, 100, 110 degrees) to study their impact on maximum axial forces during plunge steps. Results showed that higher rotational speeds and larger tool pin angles generally decreased the first maximum force, while only tool pin angle significantly affected the second maximum force. Optimized parameters were determined to be the highest rotational speed with tool pin designs at the 100 or 110 degree levels.

1. Friction Stir Welding (FSW)
An Investigation of Force Generation
Student :
Mohamad Mojoudi

2. Chapter Four
Experimental work

3. Fixture and Loadcell
 Design concerns of fixture:
◦ Good thermal conductivity by using a copper plate
◦ Good strength to avoid deformation by process loads
◦ Accurate locators to locate weld pieces and avoid weld line movements
◦ Ability to join with loadcell by a bolt and two locators
◦ Closest distance between clamps and weld line to avoid residual stress
 Loadcell features:
◦ Capacity : 50 tone
◦ Resolution : 5 kilogram
◦ Response speed: 20data/sec

4. Fixture and Loadcell

5. Process Parameters
 1-Rotational speed on three levels:
◦ 800 rpm
◦ 1000rpm,
◦ 1200rpm
 2-Tool pin design on three levels:
◦ Angle of truncated cones :
 90˚
 100˚
 110˚

6. Tool Design Specifications

7. Tool Features
 Tool Material:
◦ Hot worked steel H13
 Heat treatment procedure:
◦ Preheat: 815˚C
◦ Hardening temperature: 1000 ˚C
◦ Hardening time: 20 minutes
◦ Quenching procedure: cooled by air

8. Weld Piece Material
 Aluminum Alloy 6061-T6
 Composition:
 Silicon : 0.4-0.8 %
 Copper : 0 – 0.7 %
 Manganese : 0 .15 – 0.4 %
 Magnesium : 0.8 – 1.2 %
 Chromium : 0.04 – 0.35 %
 Zinc : 0 – 0.25 %
 Titanium : 0 – 0.15 %
 Other : less than 0.05 %

9. Axial Force During Plunge
Step
 Tool Type: Level -1
 Rotational Speed: Variable

10. Axial Force During Plunge
Step
 Tool Type: Level 0
 Rotational Speed: Variable

11. Axial Force During Plunge
Step
 Tool Type: Level +1
 Rotational Speed: Variable

12. Axial Force During Plunge
Step
 Tool Type: Variable
 Rotational Speed: 800rpm

13. Axial Force During Plunge
Step
 Tool Type: Variable
 Rotational Speed: 1000rpm

14. Axial Force During Plunge
Step
 Tool Type: Variable
 Rotational Speed: 1200rpm

15. Conclusions
 Increasing rotational speed cause a significant decrease in
first maximum axial force
 Increasing rotational speed do not affect second maximum
axial force as much as first one.
 So by increasing rotational speed in addition to decreasing
axial force and system’s shocks we can increase heat input
by increasing friction( Major heat is made by friction)
 Increasing the angle of tool pin ( tool level -1to level +1)
cause a considerable decrease in first maximum axial force
 Increasing angle of tool pin from level -1 to level 0 cause an
enormous increase in second maximum axial force
 Increasing angle of tool pin from level 0 to level +1 do not
influence second maximum axial force
 Increasing the rotational speed beside using tool level 0 and
+1 cause an optimized process.