Transcript Result – Mechanical properties

Microstructure and deformation mechanisms of a Mn‐based
lean 1 GPa duplex stainless TRIP steel with high ductility
C. Herrera, D. Ponge, D. Raabe
Department of Microstructure Physics and Metal Forming
Düsseldorf, Germany
Experimental procedure
Chemical composition (mass%)
Cr
Ni
Mn
Alloys 20 - 25
≤1
≤5
22.32
3.65
1.39
1.4362
N
C
0.05-0.3 ≤ 0.13
0.108
0.024
Cu
Si
Mo
≤2
≤ 0.5
-
-
0.22
0.41
Alloys
Alloy
Low Mn
High C, middle N and Mn
Low C, high N, middle Mn
Low C and N, high Mn
Mn
~3.0
~ 5.0
~ 5.0
~ 8.0
N
~ 0.20
~ 0.25
~ 0.35
~ 0.10
C
~ 0.20
~ 0.20
~ 0.03
~ 0.10
Hot rolling + Cold rolling + Annealing treatment,
TAnnealing = 1050°C/5min
MPIE
Result – Mechanical properties
Hot rolling + Cold rolling + Annealing treatment, TAnnealing = 1050°C/5min
g , %*
Md(g),
°C
YS,
N/mm²
UTS,
N/mm²
Low Mn
50
81
445
761
19
19
High C, middle N and Mn
64
64
503
1026
55
58
Low C, high N, middle Mn
60
37
475
700
31
53
Low C and N, high Mn
97
47
326
758
79
73
1.4362
57
28
432
697
51
55
Alloy
* Volume fraction of g before tensile test
MPIE
Uniform
Total
elongation, % elongation, %
Results – Microstructure
Low Mn  % gbefore = 50
% gafter = 3.3
ND
RD
(Md)g = 81°C
Ferrite
Austenite
MPIE
0°
2°
Results – Alloy with high C and middle N and Mn
Evolution of the microstructure during tensile test
 e = 0.10
 e = 0.15
 e = 0.20
 e = 0.46
(Md)g = 64°C
ND
RD
Volume fraction of g before and after tensile test:
% gbefore = 64
% gafter = 14
MPIE
Results – Alloy with Middle N and Mn
e = 0.46
bcc phases
MPIE
Austenite
e-martensite
Conclusion
The high strength level and the excellent forming properties qualify
lean duplex stainless TRIP steels for advanced lightweight and highstrength manufacturing applications in the fields of mobility, industrial
design, and energy conversion under less corrosive conditions.
MPIE
Application of lean duplex stainless steels
Offshore Brazil
Rotating Shelter - Blackpool (England)
The Helix Bridge (2010) - Singapore
Attractive combinations of good
mechanical properties and high corrosion
resistance
Weight reduction
Stonecutters Bridge (2009) - Hong Kong
MPIE