1. Neural Networks www.msm.cam.ac.uk/phase-trans

5. There are many problems where simplification is unacceptable

8. Charpy fatigue corrosion tensile critical stress intensity

9. Given a comprehensive description of material, process and structure, it is not yet possible to predict most properties.

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

11. Michael McIntyre y x

12. Solution non-linear functions large numbers of variables uncertainties exploit large knowledge base

13. Empirical Equations  y = a + b (%C) +c (%Mn) + d (%Ni)....

14.  y = a + b (%C) +c (%Mn) + d(%C x %Mn)

15.  y = a + b (%C) +c (%Mn) + d(%C x %Mn)  y = sin (%C) + tanh (%Mn)

17. Hyperbolic Tangents

26. y x A B

28. What is the range over which an empirical method should be used?

29. Outliers

30. Cole & Bhadeshia, 1999

31. 200003000040000 0 100 200 300 400 500 600 Life / hours GTA weld at 823 K (data from Nippon Steel) Cole & Bhadeshia, 1999

33. Cool, 1996

35. As-welded 600 °C 650 °C 700 °C Cool, 1996

36. Siemens Mitsui Babcock Nippon Steel ABB

37. Murugananth & Bhadeshia, 2002

38. Coalesced bainite Keehan, Karlsson, Andrén and Bhadeshia, 2005

39. Nickel base alloy FT750dc wt%

41. 0 200 400 600 800 1000 020040060080010001200 Temperature / °C Yield stress / MPa Tancret & Bhadeshia, 2002

42. International Fusion Reactor Reduced activation steels

43. Fusion Reactor Steels Kemp, Cottrell & Bhadeshia, 2006

45. Thank you

46. Classification networks