A low-cost rh decarburization and dephosphorization method

Abstract

The invention discloses a low-cost RH decarburization and dephosphorization method. The specific steps are as follows: during the tapping process of the converter, no alloy or deoxidizer is added, only slag is added; the molten steel is hoisted to the RH vacuum treatment position, and the ladle is lifted to the RH treatment tank; turn on the vacuum pump for vacuum treatment; the concentration of CO tail gas in the vacuum chamber is less than 0.5%, and carry out emptying; the molten steel is hoisted to the slag removal position to remove dephosphorization slag; the molten steel is hoisted to the LF furnace for slagging, heating, and adjustment Element. Compared with the prior art, the beneficial effect of the present invention is: under the premise that RH does not need to add slag material and oxygen blowing, the smelting C is lower than 0.01 by using the oxygen in molten steel, the slag material added in tapping and the temperature condition of molten steel to RH. %, P less than 0.008% ultra-low carbon, low phosphorus steel.

Description

technical field [0001] The invention belongs to the field of metallurgy and relates to a low-cost RH decarburization and dephosphorization method. Background technique [0002] As the main raw material for the production of deep drawing and ultra-deep drawing cold-rolled substrates, ultra-low carbon steel is widely used in industries such as automobiles, home appliances, and precision welded pipes. Phosphorus in steel significantly reduces the toughness of steel, improves the cold brittleness of steel, and is easy to segregate, affecting the local structure uniformity of steel, thereby affecting the mechanical properties of steel. At present, the production of low-phosphorus steel generally adopts pre-dephosphorization in ladle or torpedo car, double-slag dephosphorization in converter, or adding dephosphorization agent and oxygen injection in RH furnace vacuum chamber for dephosphorization. Pre-dephosphorization in the ladle or torpedo car, the temperature drop of molten i...

AI Technical Summary

Problems solved by technology

Pre-dephosphorization in the ladle or torpedo car, the temperature drop of molten iron is large, and oxygen blowing is required to supplement the temperature drop, and the volume of the ladle or torpedo car is small, the reaction is slow, and the dephosphorization efficiency is low; dephosphorization by double slag method increases converter smelting Cycle time and slag consumption reduce converter operation rate; adding dephosphorization agent and blowing oxygen dephosphorization in RH furnace vacuum chamber not only requires high equipment but also high production cost

Patent CN200810012366.5 Process method for producing ultra-low phosphorus steel by refining and dephosphorizing molten steel outside the furnace. Deoxidation is not performed when tapping the converter, and dephosphorization is performed by adding a dephosphorization flux. Deep dephosphorization is performed by adding composite spheres in RH, and the dephosphorization is carried out after dephosphorization. For slag removal, since compound spheres need to be added for dephosphorization during RH treatment, the requirements for equipment are relatively high, and the cost investment is large; patent CN200810035042.3 is a multi-functional vacuum refining process that not only needs to add a specific dephosphorization agent during RH dephosphorization Dephosphorization, and desulfurization and deoxidation operation after dephosphorization, if the dephosphorization slag is not removed, it is easy to cause the phosphorus in the slag to return to the molten steel, so it is difficult to achieve a better dephosphorization effect

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