According to the research prototype of a 35 t tundish for casting three-strand unsymmetrical 320 mm x 480 mm bloom of GCrl5 bearing steel

with using geometric similarity ratio 1：3 water model combined with mathematical simulation

the effect of different baffle device on liquid flow field in tundish is studied to optimize the tundish flow field and get optimum baffle device. Results show that of original prototype tundish the residence time is smaller and the dead area volume fraction is up to 39. 68% ; adding optimized Y-type baffle the average residence time of three nozzle increases by 29. 51 s

the dead area ratio decreases by 15. 54% and each nozzle is more identical. The pilot production of GCrl5 beari

ng steel in situ show that after tundish optimization the T [O

]

in tundish liquid decreases from original 19. 3 x 10

-6

~26. 3 x 10

-6

average value 22. 7 x 10

-6

to 9. 5 x 10

-6

~ 17. 2 ×10

-6

average 12. 3 x 10

-6

number of inclusions in casting bloom decreases from 12. 0 ~15.3/mm

2

to 6. 8 ~8. 4/mm

2

and the number of > 1. 25 μm inclusions decreases obviously.