Fast Cooling Process of Q460D Heavy Plates

The trials of 60 mm gauge plate steel were conducted by using CR+FC (control rolling + fast cooling) process with continuous cast slabs in this paper. The effects of cooling rate and finish cooling temperature on strength and toughness of the plates were studied. The results reveal that, with the increase of cooling rate, the ferrite grain decreases, and the strength and toughness improves. The decrease of finishing cooling temperature results in the refinement of grain size and great improvement of low temperature toughness, but a modest effect on strength. When cooling rate is about 5.8 °C/s and finish cooling temperature is about 430 °C, the steel is composed of ferrite, acicular ferrite and bainite, and conforms to national standard for Q460D heavy plates, which provides fundamentals for performance improvement of higher strength steels.