Cleanliness control of IF steel during the RH refining process

The influences of RH circulation time after Ti alloying,holding time,and the T. Fe content in ladle slag on the T[O] content of IF steel were studied to optimize the RH process parameters and improve the cleanliness of IF steel after RH treatment. The results show that appropriately prolonging the circulation time is favorable for improving the cleanliness of IF steel. The T[O]content of molten steel after RH degassing can be decreased below 30×10^-6 if the circulation time is more than 6~8 min after Ti alloying. The T[O]content of molten steel in tundish generally decreases with increasing the holding time after RH treatment,and the T[O]content can be decreased below 35×10^-6 when the holding time is more than 30 min. When the T. Fe content in ladle slag is increased by 1%,the average loss rate of Al and Ti is increased by 1.05×10^-6 min^-1,wherein the loss rate of Al is 0.40×10^-6 min^-1 and that of Ti is 0.65×10^-6 min^-1.