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Thin-strip continuously cast high-reaming steel and production method thereof

A production method and technology of reaming steel, applied in thin strip continuous casting high reaming steel and its production field, can solve the problems of inability to measure the temperature of the steel plate in the air-cooling section, large changes in the speed of the strip, and influence on surface quality

Inactive Publication Date: 2021-03-19
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] With the increasing requirements of automobile design on the chassis structure, the forming of parts is more complex, and the requirements for flanging and hole reaming performance of steel plates are further improved. The strength and rigidity of parts can be improved through the shape design of flanging and local reaming of automobile parts, which can To achieve the purpose of reducing the thickness and weight of automobile steel plates, traditional carbon-manganese solid-solution strengthened steel and low-alloy precipitation-strengthened steel structural steel plates are difficult to meet the forming requirements of automobile chassis and cantilever parts, such as traditional 440MPa steel plate carbon-manganese solid-solution strengthened steel and low-alloy The hole expansion rate of precipitation strengthened steel is only between 50% and 70%, thus the high hole expansion steel was born
In the 1990s, the United States and Japan successively developed hot-rolled steel sheets with high hole expansion performance of 440-780MPa, and the hole expansion rate was 70%-131%. They are mainly used in formability, especially those that require good flanging performance. For automobile chassis, wheels and other parts, the hole expansion performance of the steel plate is related to the composition, strength and structure uniformity of the steel plate. Because it contains more precious alloy elements Cr, Nb, Ti, V and Mo, etc. Ferrite / bainite dual phase structure can be obtained under the same conditions, but its cost is higher
At the same time, the contact of high-temperature strip steel with cooling water will cause many problems: first, water spots (rust spots) will be formed on the surface of the strip steel, which will affect the surface quality; second, the cooling water used for laminar flow cooling or spray cooling It is easy to cause uneven local cooling on the surface of the strip, resulting in uneven microstructure inside the strip, resulting in uneven performance of the strip, affecting product quality and hole reaming performance; third, uneven local cooling on the surface of the strip will cause The deterioration of the shape affects the quality of the shape
[0017] Chinese patents CN105154769 and CN106119702 respectively disclose a kind of 780MPa and 980MPa grade hot-rolled high-strength high-reaming steel and its manufacturing method, both of which are in the category of high-strength steel. Multi-microalloying elements are used to strengthen the steel type, and the alloy cost is relatively high; at the same time, its production method adopts traditional continuous casting + traditional hot rolling process to produce
[0018] International patent WO200928515 uses C, Si, Mn to add a small amount of Nb, Ti alloy elements, and can produce reaming steel with a tensile strength above 490MPa. Hot rolling must adopt a two-stage laminar flow cooling method, which can be more accurately simulated in the laboratory. However, in hot rolling production, the strip speed changes greatly during hot rolling, and the temperature of the steel plate in the air cooling section cannot be measured. A two-stage cooling model is used to control laminar cooling, and the steel plate The actual temperature fluctuates greatly, which will easily lead to large fluctuations in the performance of the steel coil head, middle and tail

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  • Thin-strip continuously cast high-reaming steel and production method thereof
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  • Thin-strip continuously cast high-reaming steel and production method thereof

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Embodiment Construction

[0086] The present invention will be further illustrated below with examples, but these examples are by no means any limitation to the present invention. Any changes made by those skilled in the art in the implementation of the present invention under the inspiration of this specification will fall within the protection scope of the claims of the present invention.

[0087] Such as figure 1 As shown, the process of the present invention is implemented, and the molten steel conforming to the chemical composition design of the present invention is directly poured in a two-way nozzle through the ladle 1, the tundish 3, the submerged nozzle 4 and the flow distributor 5 through the ladle 1. In the melting pool 7 surrounded by two relatively rotating crystallization rollers 8a, 8b capable of rapid cooling and side sealing plate devices 6a, 6b, molten steel solidifies on the circumferential surface of the crystallization rollers 8a, 8b rotation, and then forms a solidified shell and ...

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Abstract

The invention discloses thin-strip continuously cast high-reaming steel and a production method thereof. The steel comprises the following chemical components in percentage by weight: 0.01-0.05% of C,0.2-0.6% of Si, 0.8-1.5% of Mn, smaller than or equal to 0.02% of P, smaller than or equal to 0.005% of S, smaller than or equal to 0.008% of N, smaller than 0.001% of Als, smaller than or equal to 0.0050% of Ca, greater than 250 of Mn / S, 0.007-0.020% of total oxygen [O]T and the balance of Fe and other inevitable impurities. In the smelting process, the alkalinity of slag, the types and meltingpoints of inclusions in the steel, the content of free oxygen in molten steel and the content of acid-soluble aluminum Als are controlled; then a cast strip with a thickness of 1.5-3 mm is cast through twin-roll thin-strip continuous casting, and the cast strip directly enters a lower closed chamber with a non-oxidizing atmosphere after being discharged out of a crystallization roller and enters an online rolling mill under the closed condition to be subjected to hot rolling; strip steel is cooled in a gas atomization cooling manner after being rolled; and finally the produced steel coil can be directly used as a hot rolled plate and can also be used after being subjected to acid pickling and leveling.

Description

technical field [0001] The invention relates to a production process of high-hole-expanding steel, and mainly relates to a strip continuous casting high-hole-expanding steel and a production method thereof. Background technique [0002] Most of the traditional thin strip steel is produced by multi-pass continuous rolling of the slab with a thickness of 70-200mm. The traditional hot rolling process is: continuous casting + slab reheating and heat preservation + rough rolling + finishing rolling + cooling + Coiling, that is, firstly obtain a cast slab with a thickness of about 200mm through continuous casting, reheat the cast slab and keep it warm, then perform rough rolling and finish rolling to obtain a steel strip with a thickness generally greater than 2mm, and finally process the steel strip Laminar cooling and coiling complete the whole hot rolling production process. If it is necessary to produce a steel strip with a thickness of less than 1.5mm (inclusive), it is rela...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/06C21D8/02C22C33/04B22D11/06
CPCC22C38/02C22C38/04C22C38/002C22C38/001C22C38/06C21D8/0226C22C33/04B22D11/0622C21D2211/005C21D2211/002
Inventor 方园吴建春
Owner BAOSHAN IRON & STEEL CO LTD
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