1. Alloy consumption and steel consumption per ton
It is mainly related to steel grade, composition in furnace and oxidation of molten steel in tapping process. There are two ways of alloying, one is weak first and then strong, and the other is strong first and then weak. Consumption control mainly includes alloy grade and oxidation of molten steel. The cost control needs to formulate the quota, and the general alloy absorption rate refers to 85% of silicon, 95% of manganese and 96% of vanadium. Calculation method of alloy addition:
[middle limit of composition%] steel grade - [residual content%] end point alloy addition (kg / furnace) = --------------------------------———————— × Amount of steel (kg / furnace) alloy composition% × Alloy yield%
2. Oxygen lance
During the oxygen opening operation of the oxygen lance in the furnace, the speed of oxygen passing through the basic medium and the sound speed of the oxygen lance also have an impact on the oxygen supply time of the converter. The supersonic oxygen lance can improve the smelting speed of the converter, which is used by all steel mills. However, when the oxygen jet is submerged in the foam slag, it has little influence on the external interference. calculation: α= ( κ gRT)1/2m/s α— Sound speed under local conditions, M / S; κ— Heat capacity ratio of gas, for air and oxygen, κ= 1.4； G-gravitational acceleration, 9.81m/s ²； R - gas constant, 26.49m/ κ.
3. Mach number
It is a term for the impact depth of the oxygen lance on the molten pool of the converter. The general design parameters are the middle and lower limit for the converter below 1.6 ~ 1.8100t and the upper limit for the converter above 100t. When the Mach number is one, the impact depth of the oxygen lance is related to the pressure and gun position of the oxygen lance. The impact depth value is 600mm-800mm, and the height of the molten pool is generally 900mm-1200mm. A certain safety distance is reserved at the bottom of the molten pool to protect the furnace bottom from large fluctuations and realize safe smelting. Calculation formula: M= ν/α M - Mach number; ν— Gas flow rate, M / S; α— Speed of sound, M / s.
4. Oxygen lance height
It refers to the distance from the molten pool liquid level in the process of oxygen lance smelting, including basic height, process height and end height. The basic height of converter below 100t is 700mm-1000mm, the process height is 1000mm-1600mm, and the end height is 700mm-900mm; The basic height of the converter above 100t is 1000mm-1200mm, the process height is 1200mm-1800mm, and the end height is 800mm-900mm. The height of each gun position ensures that the converter can heat up and slag quickly, the process slag is submerged in arc, the final slag is sticky, and the oxidizability is weak. Calculation formula: H = bpdeh - the height from the end face of oxygen lance nozzle to the liquid level of molten pool, mm; B - coefficient, which varies with the number of spray holes, four hole nozzle B = 45 ~ 60; P - oxygen supply pressure, MPa; De - nozzle outlet diameter, mm.
