www.msm.cam.ac.uk/phase-trans

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Silicon-Rich Bainitic Steel Welds
www.msm.cam.ac.uk/phase-trans
M. Lord L.-E. Svensson
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Previous work Inspiration from steels Novel weld
microstructure Two weld design models Experimental
results Difficulties
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G. M. Evans, Metal Construction, 1986
C 0.060-0.073 Mn 0.60-1.82 Si 0.20-0.95 wt
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Microstructures Allotriomorphic
ferrite Widmanstätten ferrite Acicular ferrite
Recrystallise easily
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Carbon supersaturated plate
Carbon diffusion
Cementite precipitation
UPPER BAINITE
LOWER BAINITE
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g
g
a
a
a
20 nm
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50 µm
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T-zero curves
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kilocycles to Crack Initiation
Yates, Jerath
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Yates, Jerath
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Design criteria for welds T0 curve at high
carbon Sufficient hardenability
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MULTIPASS ARC WELD
L.-E. SVENSSON
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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
10
Time / s
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Bhadeshia Svensson, 1989
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Fe-1Mn-C wt manual metal arc welds
Allotriomorphic
Volume fraction
Widmanstatten
Acicular
Carbon / wt
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wt
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Weld microstructures, with good properties,
containing mixtures of austenite and
bainitic-ferrite can be created. Data and theory
for silicon in steel needs improvement
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Best wishes for the next 30 years