Research On Cooling Process Of SWRH82B High Carbon Steel Of HAN Steelmaking

With the rapid development of national economic construction,the performance requirements and demands of steel bars for construction were constantly increased.The portion of hot rolled steel bars used in construction is more than 90% in China.High carbon steel billet bears higher carbon content,wider two phase region and longer solidification time with ordinary steel,the carbon macrosegregation in billet was particularly serious,and carbon segregation on subsequent rolling had been severely affected the internal quality,microstructure and mechanical properties.Macrosegregation of carbon in billet was formed in solidification process,which was closely related to solidification characteristics,microsegregation and microstructure of steel.Based on the actual production situation of Shaanxi Steel Group Hanzhong Iron and Steel Co.,Ltd.(hereinafter referred to as “ Hanzhong Iron and Steel”)SWRH82B billet network cementite defects,and systematically analysis the production process key control elements of the production technology for continuous casting process parameters for numerical simulation research,combined with semi industrialization experiment for Hanzhong Iron and Steel SWRH82 B steel high carbon steel quality production to provide theoretical and practical support.This subject adapts the method of combining the numerical simulation and experiment,analyzes the SWRH82 B steel production factors,the related experiment analysis network cementite was mainly caused by slab macrosegregation,temperature field of molten steel and inclusion content were numerically simulatedby FLUENT software GAMBIT and programs for the company’s actual eight strand tundish and secondary cooling zone size,scaling,such as modeling and flow field,the current continuous casting speed,and degree of superheat and secondary cooling zone than water,such as electromagnetic stirring process parameters optimization and in combination with half industrialized experiment basically eliminated timber net cementite.The main research conclusions of this topic were as follows,physical and chemical analysis was carried out on the main defects of SWRH82,the overall soxenitization rate was between 88% and 89%,and the soxenitization remains good.The inclusion from the results of segregation was represented by carbon segregation and the inclusion is all silicate C inclusion.Compared with the billet pulling speed between 1m/min and 2.5m/min,the vertical position speed changes the most when the billet pulling speed was 2m/min,so as to promote the gas floating in the liquid steel.The overall gas content was low,which was conducive to promoting the homogenization of the components in the liquid steel,and the inclusion content is lower.The casting temperature of the tundish was controlled at about 1761 K,and the specific water of secondary cold water was reduced to 1.8l /kg to reduce the content of class C inclusions.The end electromagnetic stirring current was set at 370 A,the frequency was set at 7Hz,and the carbon segregation index decreased significantly.