The hot compression test on 4>5 mm x 86 mm test specimen cut from 80 mm hot-rolled plate of steel EH460 (/% : 0.07C
0.39Si
1.76Mn
0.34Ni
0.36Cu
0.02〜0.05Nb
0.05~0.10V
≤0.02Ti
0.008Als) with 10℃/s heating to 1200 ℃for 5 min austenizing then with 10°C/s cooling to 830 °C and with strain rate 1 s
-1
deformation 30% at 830°C
then cooling to ambient temperature with 1~30°C/s has been carried out by using a Gleeble-3800 thermal simulation testing machine. And the dynamic continuous cooling transfonnation (CCT) curves of tested steel EH460 is obtained by dilation-temperature curves combined with structure at different cooling rate and using Origin software. Results show that with cooling rate less than 3 °C/s the structure of steel EH460 is fer
rite + minor bainite
with cooling rate 5~10°C/s the structure is bainite + minor ferrite and with cooling rate more than 20 °C/s the structure is mainly lath bainite with little granular bainite ; with cooling rate increasing from 1 °C/s to 30 °C/s the HV hardness value of the steel increases form 246 to 274.