According to hot simulation test results by Gleeble 1500D machine
the analytic expression between flow peak stress σ
p
and Zener-Hollomon factor Z ( T
ε ) for Ti-Nb IF ( interstitial atom free) steel (0. 005C
0. 055Al
0. 01 Nb
0. 08Ti) in ferrite temperature area (840 - 780 °C ) has been obtained ; and the hot processing map for the steel has been established by using power dissipation map and working instability map for test steel in ferrite deformation area to get its processing safety area and instability area. Results showed that the area with deformation temperature 800 ~ 825 °C and strain rate 0. 02 ~ 0. 002 s
-1
was processing safety ferrite area for hot workability of the Ti-Nb IF steel.