Creep-Resistant Steels Success and Failure of Models H

Creep-Resistant Steels Success and Failure of Models H. K. D. H. Bhadeshia T. Sourmail

Z-phase, inaccurate data

2. 25 Cr 1 Mo 600°C

Yamasaki & Bhadeshia, 2003

x

Coarsening diffusion flux r concentration 1 q r 2 a aq cr 1 q aq cr 2 distance

Mean radius / m 10 -6 10 -7 10 -8 10 -9 1/3 1/2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 10 10 Fujita & Bhadeshia, 2000 18 m -3 4 2 10 Number density Time / s 0 2 10 10 3 10 4 10 5 10 6 10 Time / s 7

10 1 Data from Abe, 1999 M_23 C_6 size / µm 0 W 1 W 2 W 4 W 10 10 -1 10 Fe-9 Cr-W alloys 0 -2 10 1 10 2 10 3 Time at 600 °C / h 10 4

Mole fraction of phase 0. 03 M_23 C_6 0. 02 0. 01 0. 00 Laves phase 0 1 2 3 Tungsten / wt% 4 5

Multicomponent coarsening Venugopalan & Kirkaldy, 1978

Effective diffusivity / m s 2 -1 Coarsening accelerated by tungsten 1. 8 e-19 chromium alone 1. 7 e-19 1. 6 e-19 multicomponent 1. 5 e-19 0 1 2 3 4 Tungsten / wt% 5

concentration in ferrite Multiphase coarsening ? Laves q q distance

Parametric methods

Alloys designed at Cambridge University and made by Nippon Steel

Data from Manoir Industries Rupture stress / MPa 9 Cr 1 Mo type steel (Z 1092, 600 °C) 300 200 100 0 0 1 2 3 log (life / h) 4 5

Linkweld Project, Siemens Power Generation W 5397 Weld Metal Rupture at 570 °C 500 400 300 200 100 0 2 3 4 5 log(life / h) 6 Cole and Bhadeshia, 2000

Components of Creep Strength 2. 25 Cr 1 Mo 550 °C iron + microstructure solid solution precipitates 600 °C Murugananth & Bhadeshia, 2001

Source code Compiled programs Web-based calculators www. msm. cam. ac. uk/phase-trans

Nonaka, Ito, Ohba and Abe, this meeting, p. 401

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