Control method of solid solution carbon content in ultra-low carbon bake-hardening steel slabs

Abstract

The invention relates to an ultra-low-carbon bake-hardened steel slab, the weight percentages of chemical components are: C: 0.0015-0.0030%, Si≤0.03%, Mn: 0.30-0.60%, P: 0.030-0.050%, S≤ 0.015%, Alt: 0.015-0.060%, Nb: 0.005-0.025%, N≤0.0050%, B: 0.0005-0.0020%, and the balance is Fe. It also relates to a method for controlling the solid solution carbon content of ultra-low-carbon bake-hardening steel, comprising the following steps: performing pre-desulfurization and slagging treatment on molten iron in sequence to obtain the first molten iron with a sulfur content of ≤0.003%; the first molten iron is smelted Obtain the first molten steel with a carbon content of 0.025% to 0.050%; refine the first molten steel through a vacuum refining furnace to obtain the second molten steel; send the second molten steel to the continuous casting process and inject it into a carbon-free tundish, and control the The amount of carbon added to the second molten steel is less than or equal to 0.0003%, and an ultra-low-carbon bake-hardened steel slab is obtained by casting the second molten steel. The control method shortens the smelting time in the vacuum refining furnace, improves the production efficiency, and at the same time improves the one-time smelting hit rate of the slab components.

Description

technical field [0001] The invention relates to the technical field of steelmaking, in particular to a method for controlling the solid solution carbon content of an ultra-low-carbon bake-hardened steel slab. Background technique [0002] Bake hardening value is an important performance index of bake hardening steel. The solid solution carbon content has a great influence on the bake hardening value, especially for ultra-low carbon bake hardenable steels. Therefore, in the development process of ultra-low carbon bake-hardening steel, the requirements for solid solution carbon content are generally very strict, and the error range of the target value is as narrow as ±0.0003% by mass. The solid solution carbon content is mainly controlled by the carbon content and the content of alloying elements such as Nb, and is generally controlled by adjusting the amount of Nb alloy added according to the carbon content. [0003] The production method of ultra-low carbon bake-hardening ...

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Problems solved by technology

[0004] The embodiment of the present application provides a method for controlling the solid solution carbon content of ultra-low carbon bake-hardening steel slabs, which solves or partially solves the problem that the production method of ultra-low-carbon bake-hardening steel in the prior art cannot control the carbon content well The deviation of the solid solution carbon content caused the technical problems of low smelting hit rate of solid solution carbon content, long smelting time and high cost, and achieved the goal of shortening the smelting time in the vacuum refining furnace, improving production efficiency and increasing the slab component smelting hit rate at the same time technical effect

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