Reliability of Weld

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Reliability of Weld Microstructure Property
Calculations
Comfort A. Adams Lecture, 2004
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Are experiments necessary when designing welding
alloys?
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Fe
Ru
6d 2s
Os
Hs
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tallest building in the world
earthquakes
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Variables

• C, Mn, Si, Ni, Cr, Mo, V, Co, B, N, O..
• Thermomechanical processing of steel
• Welding consumable
• Welding parameters
• Subsequent heat treatment

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20 µm
Barrite, 1982
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Manual Metal Arc Weld 180 Amps 34 Volts 4
mm/s 200 C interpass
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calculations
800
2
1
3
4
700
5
6
600
500
Temperature / C
1. Fe-0.4C
2. Fe-0.4C-2Si
3. Fe-0.4C-1Ni
400
4. Fe-0.4C-1Mn
5. Fe-0.4C-1Mn-1Cr
300
6. Fe-0.4C-2Mn
200
0 1 2 3
4 5
10 10 10 10 10
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Time / s
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Barrite, 1982
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Barrite, 1982
5 µm
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Fe-1Mn-C wt manual metal arc welds
Allotriomorphic
Volume fraction
Widmanstatten
Acicular
Carbon / wt
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Bhadeshia Svensson
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Young Bhadeshia, 1994
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Bhadeshia Svensson
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Charpy
fatigue
tensile
critical stress intensity
corrosion
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non-linear functions
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y
A
B
x
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Cole Bhadeshia, 1999
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Cool, 1996
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Cool, 1996
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600 C
As-welded
700 C
650 C
Cool, 1996
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Weld Shape - Spot Weld
Walsh et al. 2002
Power 2.5 kW
Power 1.4 kW
Power 1.0 kW
0.15 s
0.15 s
0.15 s
0.165 s
0.65 s
0.65 s
1.15 s
0.18 s
1.15 s
1.65 s
0.195 s
1.65 s
0.21 s
2.15 s
2.15 s
0.225 s
2.65 s
2.65 s
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Walsh et al. 2002
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Weld Shape - Stitch Weld at 2.26 kW Laser Output
Laser beam
Fusion Zone
Laser beam
Keyhole
Walsh et al. 2002
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Are experiments necessary when designing welding
alloys?
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www.msm.cam.ac.uk/phase-trans