| At present,the production of clean steel is mainly realized through the long process of molten iron pretreatment,converter,ladle refining(LF,RH)and continuous casting.The process has many shortcomings such as long flow,low efficiency,high cost and poor flexibility.In this paper,ladle bottom blowing process and ladle powdering process are added to the existing converter tapping process,and the injection refining process is developed.In the converter tapping process,the combined action of impact kinetic energy,bottom blowing argon stirring and refining powder injectioning is used to realize the secondary refining of molten steel.The key to the success of the injection refining process of the converter is its efficiency and effect,so it is necessary to carry out research work on the multiphase of the injection refining process of the converter.The research content and the results obtained in this paper are as follows:(1)Physical simulation of gas-liquid-powder three-phase flow transport in the process of injection refining of converter tapping process.Based on the similarity principle,a 1:6 ratio plexiglass model of injection refining process in the process of steel tapping of converter was established,and a water model experiment of injection refining in the process of steel tapping of converter was carried out,examines the injection Angle,injection gun to gun steel liquid steel flow distance and carrier gas flow rate,of injected powder particle size on the powder injectioning process of the converter steel refining process the influence law of powder injection rate.At the same time,the effects of the injection rate of powder and the flow rate of argon blowing at the bottom of ladle on the mixing time and degree of ladle molten pool were investigated.In the water model experiment,the powder injection rate firstly increases and then decreases with the increase of the inj ection Angle of the injection gun.When the injection Angle of the injection gun is 45°,the powder injection rate reaches the highest.With the increase of the distance between the injection gun and the molten steel,the injection rate of powder decreases.With the increase of the distance between the injection gun and the molten steel from 8 cm to 40 cm,the injection rate decreases from 85.1%to 36.4%.With the increase of the powder carrier gas flow,the powder injection rate increases firstly and then decreases,when the powder carrier gas flow is 23 NL/min,the maximum value is 92%.With the increase of the powder particle size,the powder injection rate also increases,but the powder particle size is more than 24 mesh,the injection gun will be blocked,so in the powder pipeline is not blocked,the injection operation is smooth,the best powder particle size is 24 mesh;The mixing time of molten pool increases with the increase of bottom blowing flow rate.With the change of bottom blowing flow rate from 0 NL/min to 4.9 NL/min,the mixing time decreases from 122 s to 76 s.(2)Numerical simulation of the movement and transport behavior of gas-liquid-powder three-phase flow in the process of injection refining of converter tapping process..Out of bof was established based on the euler-euler model steel powder injectioning process of refining process and the mathematical model of combined water model experiment of the converter tapping powder injectioning process of refining process of molten pool powder concentration is verified,further examines the actual process of carrier gas flow rate,of injected powder particle size and the bottom blowing argon flow on powder motion state and the influence of the distribution.In the process of numerical simulation,the distribution of powder presents a non-uniform and symmetrical distribution.The distribution range and concentration of powder are larger on the side of the injection gun,and the distribution of powder is smaller on the side of the bottom blowing brick.Due to the influence of bottom blowing argon,the velocity of flow field is faster and the distribution of powder is smaller.With the increase of the powder carrier gas flow,the powder concentration in the molten pool decreases,and the mixing degree increases first and then decreases.The amount of powder splashing in the molten pool increases first and then decreases with the increase of powder particle size.When the powder particle size is 0.8 mm,the powder splashing phenomenon in the molten pool is the least.As the flow rate of bottom blowing argon increases,the level of powder mixing in the molten pool increases first and then decreases.When the flow rate of bottom blowing argon is 450 NL/min,the powder mixing state in the molten pool is the best.(3)Through water model and digital model research,it is found that the optimal parameters of powder injectioning refining process in the process of steel tapping of converter are as follows:injection Angle of injection gun is 45°,distance between injection gun and liquid steel stream is 48 cm,powder carrier gas flow is 3500 NL/min,powder particle size is 0.8mm,bottom blowing argon gas flow is 450 NL/min. |
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