The dynamic recrystallization behavior of Cu-P-Cr-Ni-Mo weathering steel (% ： 0. 10C

0. 075P

0. 65Cr

0. 22Ni

0.43Mo

0. 28Cu) with strain rate 0. 01 ~ 1 s ~1 at 850 — 1 150 T： has been studied by Gleeble-3500 thermal simulation test machine to get true train-true stress curves in austenite area and dynamic recrystallization diagram of the steel

the effect of deformation parameters on peak stress and the relation between true strain and volume fraction of dynamic recrystallization of the weathering steel with various hot deformation are analyzed

and the thermal deformation formula of austenite of the steel

the regression formula of dynamic recrystallization at critical conditions and the math model of dynamic recrystallization volume fraction of austenite are established. Results show that with raising deformation temperature the peak stress decreases and with increasing strain rate the peak stress increases ； with increasing Z parameter i. e. decreasing deformation temperature and increasing strain rate the critical strain of occurred recrystallization and the strain εs of occurred complete recrystallization increase linearly.