Control of surface transverse crack on tail of 400 mm ultra-heavy slab
The casting of the tail slab belongs to the unsteady state casting.With the thickness of slab increasing,the surface transverse crack on the tail slab becomes the main factor that influences the quality of the slab.By studying the influences of some factors such as chemical composition of steel grade,the secondary cooling system and the speed change of the tail slab casting on the surface transverse crack,the formation mechanism of the surface transverse crack on the tail of the ultraheavy slab was determined and the corresponding improvement measures were put forward.The soft cooling control was adopted for the secondary cooling system while casting low carbon microalloyed steel When the casting time of the tail slab under the casting speed less than 0.5 m/min was less than 5 min,the specific water flow of the secondary cooling in the casting stage of the tail slab was reduced from 0.35 L/m to 0.25 L/min,and the straightening temperature of the tail slab was controlled above 933 ℃,the surface transverse crack on the tail slab could be decreased efficiently.The reject rate of the tail slab was reduced to less than 5 ％.
ultra-heavy slabtail slabsurface transverse crackcasting speedsecondary cooling system
NETL
NSTL
万方数据
