Based on analysis on solidification characteristics of steel 37Mn5 (/% ： 0. 34 ~0. 39C

0. 20 ~ 0. 35Si

1. 25 ~ 1. 50Mn) during casting

a thermal-mechanical coupled mathematical model is established by using software ANSYS to simulate the solidification process of Φ210 mm casting round bloom and analyze with 40 t tundish

casting rate 1. 4 m/min and casting temperature 1 531 °C the effect of secondary cooling water ratio 0.58 ~ 0. 78 L/kg and distribution of water rate at each section on casting bloom surface temperature

shell thickness

length of liquid core and surface stress. The simulation results show that with increasing secondary cooling water ratio by per 0. 1 L/kg the bloom surface tem

perature decreases by about 18 ℃，while the effect of testing cooling water ratio on shell thickness at outlet of mold

length of liquid core and surface stress is not obvious. But with cooling water ratio 0. 68 L/kg the rapid re-raise temperature of bloom occurs by 185 °C in air cooling region between 0 and 1 section for original process and the max stress is up to 6. 41 X 10

7

Pa. With maintaining the same cooling water ratio 0. 68 L/kg

to control the re-raise temperature range decreases to 123 ℃ and the highest stress decreases to 4. 53 x 10

7

Pa

as a result the bloom cracks basically dismiss and the surface quality of bloom improves markedly.