5. 0.2 µm

7. Jae Hoon Jang, In Gee Kim 7

9. 1 µm

10. Fine structure
Retained austenite:
TRIP effect
no ductile-brittle transition
barrier to hydrogen
No cementite
Small concentration of C in ferrite

12. 50 µm

14. 14

16. 50 µm

18. Impact Energy Test temperature / °C 10 20 30 40 50 60 70 0.4C-3Mn-2Si10 20 30 40 50 60 70
0.4C-3Mn-2Si
0.4C-4Ni -2Si
0.2C-3Mn-2Si
200
100
-100
-200
Test temperature / °C

20. 20 µm

22. Yates, Jerath, Bhadeshia22

23. Kevin Sawley: 90 million gross tonnes of traffic on curve

24. 24

25. 25

27. Advances in carbide-free bainitic steels20 40 60 80
100
120
140
160
180
18 wt% Ni
maraging steel
Fracture toughness / MPa √m QT
2500
2000
1500
1000
Ultimate tensile strength / MPa