Double passes hot-compression test of martensite steel 403 Nb (% ： 0. 16C

11. 98Cr

0. 03Mo

0. 22 Nb

0. 01V

0. 12Ni) with internal time between passes 1 ~ 100 s and strain rate 0. 01 ~ 10 s

-1

at 950 ~ 1 150 °C has been carried out by using Gleeble-3500 thermal simulator. With summarizing established different static recrystallization math models

it is obtained that the activation energy Q

rex

of static recrystallization of steel 403 Nb is 168. 40 kJ/mol

die static recrystallization model is t

0.5

=6.599 9×10

-10

ε

-1.6

ε

-0.46

d

0

exp( 168 400 /RT). Results show that with short internal time

the steel grain size coarsens and the static recrystallization rate decreases ； with longer internal time

the static recrystalliza

tion is nearly completed with most equiaxial grains. During hot compression

the static recrystallization is almost completed with finest grains in the region with maximum shear strain.