Control method for hot rolled SPA-H strip steel surface spot-like peeling defects

A control method and surface point technology, applied in the direction of metal rolling, metal rolling, workpiece surface treatment equipment, etc., can solve problems affecting the temperature of the slab, shallow cracks on the surface of the slab, and aggravate Cu enrichment, etc., to achieve improved The effect of surface quality, good economic benefits and social benefits

Inactive Publication Date: 2019-10-08
INST OF RES OF IRON & STEEL JIANGSU PROVINCE +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

SPA-H steel has relatively high Cu alloying elements. In the continuous casting process, if the process is improper, it will easily affect the temperature of the slab, which will more easily increase the enrichment of Cu and other elements at the grain boundary, such as Figur

Method used

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  • Control method for hot rolled SPA-H strip steel surface spot-like peeling defects
  • Control method for hot rolled SPA-H strip steel surface spot-like peeling defects
  • Control method for hot rolled SPA-H strip steel surface spot-like peeling defects

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Embodiment 1

[0040]Utilize method involved in the present invention and control measure to produce SPA-H strip steel in 180 tons of converters, 1450 hot continuous rolling mills successively, target thickness specification 2.7-4.65mm totally 128 coils, technological process is as follows:

[0041] S1 hot metal KR desulfurization;

[0042] S2 converter smelting;

[0043] S3LF refining, control the mass percentage of chemical components in molten steel at the end of LF refining: C 0.055-0.095%, Si 0.26-0.34%, Mn 0.4-0.7%, P 0.075-0.095%, Cu 0.25-0.30%, S≤0.006% , Ni0.01-0.04%, Cr 0.3-0.5%, Ti 0.03%, the balance is Fe and unavoidable impurities;

[0044] For S4 slab continuous casting, the superheat of molten steel in the tundish is controlled to 20°C, and the continuous casting casting speed is 1.0 m / min. After exiting the crystallizer, secondary cooling is carried out, and the secondary cooling adopts the low-carbon steel cooling mode;

[0045] S5 heating furnace heating, place the contin...

Embodiment 2

[0054] Utilize method involved in the present invention and control measure to produce SPA-H strip steel in 180 tons of converters, 1450 hot continuous rolling mills successively, target thickness specification 1.52-5.15 totally 128 coils, technological process is as follows:

[0055] S1 hot metal KR desulfurization;

[0056] S2 converter smelting;

[0057] S3LF refining, control the mass percentage of chemical components in molten steel at the end of LF refining: C 0.055-0.095%, Si 0.26-0.34%, Mn 0.4-0.7%, P 0.075-0.095%, Cu 0.25-0.30%, S≤0.006% , Ni0.01-0.04%, Cr 0.3-0.5%, Ti 0.06%, the balance is Fe and unavoidable impurities;

[0058] S4 slab continuous casting, control the superheat of molten steel in the tundish to 30°C, continuous casting casting speed of 1.2 m / min, after leaving the crystallizer, carry out secondary cooling, and the secondary cooling adopts low carbon steel cooling mode;

[0059] Heating in S5 heating furnace, placing the continuous casting slab in a...

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Abstract

The invention discloses a control method for hot rolled SPA-H strip steel surface spot-like peeling defects. The control method sequentially comprises the following steps of S1, molten iron KR desulfurization; S2, converter smelting; S3, LF refining, and controlling the mass percentages of chemical components in molten steel at the end of LF refining; S4, slab continuous casting and controlling the superheat degree of molten steel in a tundish to be 20-30 DEG C with the continuous casting and drawing speed of 1.0-1.2m/min; S5, heating in a heating furnace and placing a continuous casting slabin a heating furnace for heating treatment with the steel loading temperature of the heating furnace not higher than 600 DEG C; S6, primary descaling; S7, roughing; S8, secondary descaling; S9, finishrolling; S10, laminar cooling; and S11, coiling. The control method has the advantages that under the condition of not improving existing equipment and not changing the production flow, the problem of spot-like peeling defects on the surface of hot rolled SPA-H strip steel is effectively solved by using the existing equipment, and the yield is improved.

Description

technical field [0001] The application belongs to the technical field of material processing engineering, and in particular relates to a control method for point-shaped warping defects on the surface of hot-rolled SPA-H strip steel. Background technique [0002] SPA-H strip steel is a weather-resistant steel with a mass fraction of Cu of 0.25-0.60%. It is mainly used to make containers. Therefore, it has high requirements on the surface quality of the strip steel. Surface quality is an important aspect that affects the quality of hot-rolled strip steel products. Now Low-Ni (Ni content mass percentage 0.01-0.04%) SPA-H strip steel produced by state-of-the-art technology is prone to "point-like warping" defects, such as figure 1 As shown, it not only caused an increase in the number of judgments, but also affected the normal production of the hot rolling mill. No such defects were found in other steel types such as Q235B, SPHC and other steels during the rolling period. The ...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/42C22C38/50C22C33/04B21B45/06B21B45/02B21B45/00
CPCB21B45/004B21B45/0203B21B45/06B22D11/16C22C33/04C22C38/002C22C38/02C22C38/04C22C38/42C22C38/50
Inventor 关建辉孙林曲锦波丁美良钱京学
Owner INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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