The simulation test on removing inclusions in original tundish and optimum tundish established an additional retaining wall has been carried out by using a geometric similarity 1: 3 water model

and based on waler-simulated test results

the structure of 40 t tundish is optimized and the pilot production of high carbon steel 82A and 72A is carried out. Results show that with optimum tundish established an additional retaining wall

the stagnation time and actual retained time are prolonged

the piston area ratio increases

and the dead zone ratio reduces ； with optimum tundish structure the effect of inclusion removal improves significantly

the inclusion number in Φ5. 5 mm coil of high carbon steel produced with optimum tundish established an additional retaining wall decreases from original 2. 06 ~ 2. 52 inclusion

/mm

2

to 0. 20 ~ 1.06 inclusion/mm

2

the size of maximum inclusion decreases from original (9. 87 ~ 13. 37) μm x (6. 29 ~ 9. 44)μm to (4. 01 ~ 8. 33 )μm x (3.41 ~ 7. 62 )μm； the number and size of large inclusions in casting billet also decrease correspondingly.