Taking Q460 steel (/% ：0. 17C

0. 35Si

1. 5Mn

0. 020P

0.020S

0. 020Nb

0. 075V) 3 250 mm x 150 mm wide slab as the research object

the solidification heat transfer model is established by ANSYS software

and the effects of casting speed

specific water rate and superheat etc process parameters on the solidification process of slab are studied. The simulation results show that when the casting speed increases by 0. 10 m/min

the surface temperature of slab at the straightening section increases by 36. 5 ℃

the slab temperature increases by 50℃，the shell thickness decreases by 2. 4 mm

and the liquid core length increases by 1. 2 m； with increase of superheat of 1 ℃

the center temperature of upper surface of slab at the straightening point increases by 1. 73 °C and the length of the liquid core is extended by 0. 11 m； therefore

the casting speed is the key to quality of slab. Production application shows that by 3 250 mm x 150 mm slab cast speed 1. 20 ~ 1. 25 m/min

with superheat 15 〜20 ℃

the temperature of slab surface at straightening section is more than 950 ℃

to decrease the rating of center porosity and segregation and obviously increase surface quality.