Views: 8 Author: Site Editor Publish Time: 2020-02-13 Origin: Site
VOD furnace decarburization process
The VOD furnace decarburization process is a process for removing carbon from materials. Its refining is mainly controlled by the supply rate (intensity) of oxygen, the height of the top-blowing oxygen gun, the degree of vacuum (the number of vacuum pumps started), and the flow of argon at the bottom.
The decarburization refining of the VOD furnace is mainly controlled by the oxygen supply rate (intensity), the height of the top-blowing oxygen gun, the degree of vacuum (the number of vacuum pump startup units), and the bottom-blown argon flow rate. The decarburization process is divided into two stages, namely the vacuum blown oxygen decarburization stage and the vacuum decarburization stage. In the initial stage of oxygen decarburization, desiliconization occurs for about 2 minutes, and then decarburization starts. At this time, in order to prevent large spraying and blocking of the feeding tube, high gun positions (≤900mm) and argon flow reduction measures can be taken. . The oxygen decarburization speed is related to the oxygen supply intensity, argon blowing intensity, initial carbon content and molten steel temperature. The initial carbon was 0.27%, the average decarburization rate was 0.0125% ∕ min, and 0.41% was 0.0188% ∕ min. Strong stirring with a bottom-blown argon intensity of 0.01 to 0.02 Nm3 ∕ (t · min) can not only reduce the oxidation of chromium, but also significantly increase the rate of decarburization. When the carbon content in the steel reaches 0.08%, vacuum decarburization should be performed. The lower the required end carbon, the lower the vacuum degree, and the longer the decarburization time, generally 15 to 30 minutes.
Since the decarburization of the VOD furnace is carried out in a vacuum process, the operation of the VOD furnace must be controlled automatically. Among them, the control of the end carbon is extremely important for the smooth progress of the entire smelting process and the control of the carbon content of the finished product. The determination of the end carbon mainly includes the exhaust gas analysis method and the gas phase carbon determination method. The exhaust gas analysis method uses an infrared analyzer to analyze the CO, CO2 and O2 components in the exhaust gas, and refers to the change in vacuum to control the refining process of VOD. This method can accurately determine the time to stop oxygen blowing, and is not limited by the specific conditions of the equipment. The gas phase carbon determination method is to measure the total amount of exhaust gas and its content of CO and CO2, to calculate the decrease curve of alkali content with time, and stop blowing oxygen after reaching the end carbon.