Production process for smelting high-level low-carbon steel at low cost

Abstract

The invention provides a production process for smelting high-level low-carbon steel at low cost. The production process for producing the low-carbon steel includes the following steps: a converter, RH refining, refining of a ladle furnace and continuous casting. The converter only undertakes partial function of decarbonization, the content of aim carbon is within 0.04 to 0.08% (mass percent), and the function of RH refining decarbonization is exerted to lead the carbon content to be within 0.01 to 0.04% according to the requirement for the content of the finished target carbon. The ladle furnace has the main functions of carbon content adjusting, desulfurizing, temperature rising and component fine adjusting; alloy is added for baking so as to lead the water content to be lower than 0.2%; therefore, the aim carbon content of the converter is high, less molten steel is oxidized, the FeO content in dregs is within 10 to 20%, and the yield rate of the molten steel can be up to 90% to the minimum degree. The invention lessens corrosion to a converter liner and reduces the alloy cost; the pollution to the molten steel by deoxidized products from RH carbon deoxidization is lessened, the using quantity of deoxidant is reduced, the carbon content is stabilized, and the smelting efficiency is obviously increased.

Description

technical field [0001] The invention relates to a low-cost production process for smelting high-grade low-carbon steel in the field of steelmaking, in particular for smelting high-grade steel with a carbon content between 0.03% and 0.08%. Background technique [0002] At present, in order to ensure the purity of billets, the process route of "converter-ladle furnace refining-RH refining-continuous casting" is generally used for smelting low-carbon steel. For low-carbon steel, the carbon content is the key factor affecting the refining rate, and the hydrogen content is the key factor to ensure the pass rate of flaw detection. When the above-mentioned process route is adopted, since the RH refining is in the last process, it plays a good role. With the degassing function, it can ensure that the hydrogen content of the finished product is within the control range, that is, the qualified rate of flaw detection of the rolled material is guaranteed. However, the decarburization t...

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Problems solved by technology

However, the decarburization tasks of this process route are all completed in the converter, and the refining function of the ladle furnace is to desulfurize, heat up and prevent carburization. Since the RH process does not have the decarburization function in order to ensure the purity of molten steel, the requirements for carbon content It is very strict. Generally, the carbon content of steel grades with a finished product target of 0.06% (the content is mass percentage, the same below) must be less than 0.03% in the converter, and for steel grades with lower carbon content, the carbon content at the end of the converter will be more Low, which leads to very strong peroxidation at the end of the converter. A considerable part of the molten steel, up to 20%, is oxidized. Generally, the FeO% content in the slag is as high as 30%, which seriously increases the loss of steel materials, molten steel yield, and tapping. The minimum amount of iron and steel material in the furnace is only 80%, and a slight fluctuation will cause the carbon content to exceed the standard, resulting in failure of smelting, resulting in a change of judgment or even a return to the furnace