Forgeabilité des aciers inoxydables austéno-ferritiques

tel-00672279, version 1 - 21 Feb 2012
Chapter III. HOT CRACKING RESISTANCE 79
The total specific work of fracture, wtot, was calculated from the areas under the load-displacement
curves. Typical load-displacement curves obtained are presented for both morphologies in Figure
III.39. Up to the maximum force, the curves corresponding to the two morphologies overlap. However,
after the maximum, the D2_E microstructure shows more elongation.
As in the previous section, the total specific work of fracture is plotted as a function of the ligament
length l0. The results obtained with a model Widmanstätten microstructure D2_W are reported on the
same graph (Figure III.40) in order to provide a comparison between the two austenite morphologies.
Force (KN)
12
10
8
6
4
2
0
l 0=22mm
D2_W
D2_E
0 2 4 6 8 10
Displacement (mm)
a) b)
Force (KN)
12
10
8
6
4
2
0
l 0=32mm
D2_W
D2_E
0 2 4 6 8 10
Displacement (mm)
Figure III.39. Comparison between typical force-displacement curves (alloy D2) for both austenite morphologies;
a) l0=22mm; b) l0=32mm.
w tot (kJ.m -2 )
800
700
600
500
400
300
200
100
0
D2_E
D2_W
y = 14.544x + 144.6
R² = 0.9869
y = 13.758x + 88.261
R² = 0.9713
0 4 8 12 16 20 24 28 32 36 40
l 0 (mm)
Figure III.40. Variation of the specific work of fracture as a function of the ligament length for separation
of the essential work of fracture. Comparison between the two microstructures at 1050°C: D2_E and
D2_W.