By measuring the dilatometric curves of Nb-Ti-V micro-alloying 0.04 ~ 0.08C-0. 6 ~ 1.2Ni-0.1 ~ 0. 5Cr- 0.1 ~0.5Cu crack-resistant steel EH47 for large container ship with cooling rate of 0. 05 ~50 ℃/s on a Gleeble-3800 thermomechanical simulator

and combining with metallographic analysis

a CCT diagram of austenite continuous cooling transformation is obtained. And the microstructure and hardness of the continuous cooling transformation occurring in EH47 crack-resistant steel are investigated. The results show that the microstructure of EH47 crack-resistant steel at 0. 05 〜 50 ℃/s cooling rate consists of ferrite + pearlite and accicular ferrite + bainite. Even the cooling rate as high as 50℃/s

no martensite occurs in the microstructure.