CN-122013059-A - Low-carbon steel for improving oxidation resistance of surface of hot-rolled strip steel and preparation method thereof

Abstract

The invention discloses a low-carbon steel for improving the oxidation resistance of the surface of a hot-rolled strip steel and a preparation method thereof, belonging to the technical field of steel materials, and the technical scheme is characterized in that the low-carbon steel for improving the oxidation resistance of the surface of the hot-rolled strip steel comprises, by mass, 0.12-0.20% of C, less than or equal to 0.30% of Si, 0.30-0.70% of Mn, less than or equal to 0.030% of P, less than or equal to 0.025% of S, 0.05-0.15% of Cr, and the balance of iron and unavoidable impurities.

Inventors

• ZHANG XIYAO
• BO YU
• KANG KUN
• FENG LEI
• KONG NING
• Bai Cheligeer
• WANG YITONG
• SUN DIANXIN
• CHEN ZHONGMING
• LI HENG
• XU MINGJIE

Assignees

• 天津荣程联合钢铁集团有限公司
• 北京科技大学

Dates

Publication Date

20260512

Application Date

20260206

Claims (9)

1. 1. The low-carbon steel for improving the oxidation resistance of the surface of the hot-rolled strip steel is characterized by comprising, by mass, 0.12-0.20% of C, less than or equal to 0.30% of Si, 0.30-0.70% of Mn, less than or equal to 0.030% of P, less than or equal to 0.025% of S, 0.05-0.15% of Cr, and the balance of iron and unavoidable impurities.
2. 2. A low carbon steel having improved oxidation resistance on a hot rolled strip as claimed in claim 1 wherein the Cr content is 0.08-0.12wt%.
3. 3. A low carbon steel having improved oxidation resistance on a hot rolled strip as claimed in claim 1 wherein the Cr content is 0.10% by weight.
4. 4. A method for producing a low carbon steel having improved oxidation resistance on the surface of a hot rolled steel strip as claimed in any one of claims 1 to 3, comprising the steps of: S1, smelting and continuous casting to obtain a continuous casting slab; s2, carrying out heat preservation on the continuous casting slab, conveying the continuous casting slab to a heating furnace, and rolling the continuous casting slab after heating; S3, cooling the rolled strip steel and coiling.
5. 5. The method of claim 4, wherein the surface temperature of the continuous casting slab is maintained at 600-800 ℃ during the heat-preservation conveying stage in the step S2, and the conveying time is less than 20min.
6. 6. The method for preparing low-carbon steel for improving oxidation resistance of the surface of hot-rolled strip steel as claimed in claim 4, wherein the method comprises the following steps: the heating temperature of the continuous casting billet in the step S2 is 1150-1250 ℃.
7. 7. The method of claim 4, wherein the finish rolling temperature in the step S2 is 980-1020℃and the finish rolling temperature is 850-890 ℃.
8. 8. The method for preparing low-carbon steel for improving oxidation resistance of the surface of hot-rolled strip steel as claimed in claim 4, wherein the method comprises the following steps: the cooling rate in the step S3 is 15-30 ℃ per minute.
9. 9. The method of claim 4, wherein the coiling temperature in the step S3 is 580-620 ℃.

Description

Low-carbon steel for improving oxidation resistance of surface of hot-rolled strip steel and preparation method thereof Technical Field The invention relates to the technical field of steel materials, in particular to low-carbon steel for improving the oxidation resistance of the surface of hot-rolled strip steel and a preparation method thereof. Background In the production process of hot rolled strip steel, a layer of iron oxide scale (the main components are FeO, fe 3O4 and Fe 2O3) is formed on the surface of the hot rolled strip steel, and the structure, thickness and adhesiveness of the iron oxide scale directly influence the final surface quality and subsequent processing performance of the strip steel. If the iron scale is too thick, the structure is loose or the adhesiveness is poor, defects such as falling off, pressing in and the like are very easy to occur in the subsequent rolling, cooling and coiling processes, surface pits, red rust spots and the like are formed, and the product grade is seriously affected. Currently, the main method for improving the surface quality of hot rolled strip steel focuses on optimizing rolling process parameters (such as heating temperature, finishing temperature, cooling rate and coiling temperature), improving the efficiency of descaling equipment and the like. However, these methods have a bottleneck in improving the effect against inherent defects caused by insufficient oxidation resistance of the material itself. In general, the composition design of a carbon structural steel such as Q235B, Q B does not contain an alloy element capable of forming a dense protective oxide film at high temperature, and therefore, the steel matrix has a limited effect of inhibiting oxidation in the whole hot rolling process. Although elements such as chromium and the like are known to improve the oxidation resistance zinc of steel, the traditional belief that the steel can have a remarkable effect only by adding higher chromium content (such as more than 0.5 percent), the alloy cost can be greatly increased, the grade of the steel is changed, and the subsequent processing performance of welding and the like can be possibly adversely affected, so that the method is a technical problem to be solved urgently on how to fundamentally improve the internal oxidation resistance of the ordinary carbon steel on the premise of not remarkably changing the mechanical property and the chemical component grade of the ordinary carbon steel. Disclosure of Invention In order to solve the problems in the prior art, the invention provides the low-carbon steel for improving the oxidation resistance of the surface of the hot-rolled strip steel and the preparation method thereof, and the oxidation resistance of the low-carbon steel at high temperature is obviously improved under extremely low cost amplification through specific micro Cr element alloying design, so that the generation amount of iron scales is reduced from the source and the structure of the low-carbon steel is improved. The first aspect of the invention provides a low-carbon steel for improving the oxidation resistance of the surface of hot-rolled strip steel, which adopts the following technical scheme: the low-carbon steel for improving the oxidation resistance of the surface of the hot-rolled strip steel comprises, by mass, 0.12-0.20% of C, less than or equal to 0.30% of Si, 0.30-0.70% of Mn, less than or equal to 0.030% of P, less than or equal to 0.025% of S, 0.05-0.15% of Cr, and the balance of iron and unavoidable impurities. In a preferred embodiment, the Cr content is 0.08-0.12 wt.%. In a preferred embodiment, the Cr content is 0.10 wt.%. By adopting the technical scheme, the internal medicine with the C content controlled in the range ensures that the low-carbon steel has good strength and plasticity and meets the basic mechanical property requirements of the marks such as Q235B, Q B and the like. Si and Mn are used as conventional deoxidizing and solid solution strengthening elements, are controlled in a lower range, can avoid adverse effects on toughness and welding performance of steel, and can prevent iron scale from being excessively strong in adhesiveness and difficult to remove in a descaling process due to excessively high Si content. P and S are used as harmful elements, and the content of the controller is strictly controlled to ensure the cold bending performance and the welding performance of the steel. The present inventors have found that the oxidation resistance of steel can be significantly improved when the Cr content is controlled within the range of 0.05-0.15%, overcoming the technical prejudice that only high levels of chromium (> 0.5%) are added, and that the present inventors have found that a sufficient concentration of Cr enrichment at the steel/scale interface can be ensured when the Cr content is 0.05wt% to form a continuous, dense chromium-rich oxide layer (mainly chromium trioxide), thereby producin