400-420mm large-thickness low-alloy high-strength constructional steel and production method thereof

A low-alloy, high-strength, production method technology, applied in the field of improving industrial steelmaking performance, can solve problems such as inability to guarantee normal operation of the project, inability to guarantee flaw detection, performance, and low market supply, so as to reduce the content of molten steel inclusions, reduce Metallurgical cost, the effect of improving comprehensive performance

Active Publication Date: 2012-10-03
NANYANG HANYE SPECIAL STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there are very few iron and steel enterprises that can produce ultra-thick Q345B steel. In addition, in the domestic market, Q345B steel with specifications above 300mm cannot guarantee flaw detection and performance, and the market supply is very small. If you rely on imports, not only the price is expensive, Moreover, the purchase cycle is long, and the normal operation of the project cannot be guaranteed.
Moreover, there is no manufacturer at home and abroad that can produce this low-alloy high-strength structural steel with a thickness of more than 400mm.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] The actual composition of the extra-thick, low-alloy, high-strength Q345B steel plate of the present invention is: C: 0.147%, Si: 0.35%, Mn: 1.52%, P: 0.012%, S: 0.001%, Als: 0.025%. Its mechanical properties are: yield strength: 305MPa, tensile strength: 500MPa, elongation: 25%, impact energy at 20°C: 192J, 166J, 233J.

[0016] The production method of the present invention is as follows:

[0017] (1) Smelting process: During converter smelting, ensure that the tapping carbon is greater than or equal to 0.06%, and the tapping P is less than or equal to 0.018%; the number of point blows should not be greater than 2 to avoid slag in the tapping process. After the molten steel is smelted, it is sent to the LF refining furnace for refining, and a large amount of slag is used for slagging to ensure that the white slag retention time is controlled above 15 minutes. The holding time of VD vacuum refining is controlled within 20-25min;

[0018] (2) Pouring process: 48 tons of ingot...

Embodiment 2

[0025] The actual composition of the extra-thick low-alloy high-strength Q345B steel plate of the present invention is: C: 0.176%, Si: 0.27%, Mn: 1.48%, P: 0.012%, S: 0.001%, Als: 0.015%, and the thickness of the rolled steel sheet It is 420mm, and its mechanical properties are: yield strength: 350MPa, tensile strength: 555MPa, elongation: 23%, impact energy at 20°C: 160J, 187J, 205J.

[0026] The production method of the present invention is as follows:

[0027] (1) Smelting process: During converter smelting, ensure that the tapping carbon is greater than or equal to 0.06%, and the tapping P is less than or equal to 0.018%; the number of point blows should not be greater than 2 to avoid slag in the tapping process. After the molten steel is smelted, it is sent to the LF refining furnace for refining, and a large amount of slag is used for slagging to ensure that the white slag retention time is controlled above 15 minutes. The holding time of VD vacuum refining is controlled wit...

Embodiment 3

[0034] The actual composition of the extra-thick low-alloy high-strength Q345B steel plate of the present invention is: C: 0.160%, Si: 0.31%, Mn: 1.50%, P: 0.012%, S: 0.001%, Als: 0.020%, and the thickness of the rolled steel sheet It is 420mm, and its mechanical properties are: yield strength: 360MPa, tensile strength: 530MPa, elongation: 26%, impact energy at 20°C: 180J, 178J, 220J.

[0035] The production method of the present invention is as follows:

[0036] (1) Smelting process: During converter smelting, ensure that the tapping carbon is greater than or equal to 0.06%, and the tapping P is less than or equal to 0.018%; the number of point blows should not exceed 2 times to avoid slag in the tapping process. After the molten steel is smelted, it is sent to the LF refining furnace for refining, and a large amount of slag is used for slagging to ensure that the white slag retention time is controlled above 15 minutes. The holding time of VD vacuum refining is controlled within...

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Abstract

The invention discloses 400-420mm large-thickness low-alloy high-strength constructional steel and a production method thereof. The 400-420mm large-thickness low-alloy high-strength constructional steel comprises the following chemical components in percentage by weight: not more than 0.18% of C, 0.20-0.40% of Si, 1.30-1.55% of Mn, not more than 0.015% of P, not more than 0.003% of S, 0.010-0.035% of Als and the balance of Fe and unavoidable impurities. In the invention, refined grain elements of Nb, V, Ti and the like are not added so that the cost of metallurgy and the content of molten steel inclusions are reduced; the processes of normalizing and wind-cooling refined grains are utilized so as to ensure the quality of the products to match the standard and the use requirements. The production processes are simple, and the constructional steel can be produced in batch. In addition, the applied strengthening mechanisms comprise a structure strengthening mechanism, a fine grains strengthening mechanism, a precipitation strengthening mechanism and a solution strengthening mechanism.

Description

Technical field [0001] The invention relates to the technical field of improving the performance of industrial steelmaking, in particular to a 400-420mm thick low-alloy high-strength structural steel and a production method thereof. Background technique [0002] At present, the extra-thick plate Q345B is generally used in vehicles, cranes, mining machinery, power stations, bridges and other structures that bear dynamic loads, mechanical parts, building structures, and general metal structures. Nowadays, there are very few steel companies that can produce extra-thick Q345B steel grades. In addition, the Q345B steel grades above 300mm in the domestic market cannot guarantee flaw detection and performance, and the market supply is very small. If they rely on imports, they are not only expensive. Moreover, the purchase cycle is long, and the normal operation of the project cannot be guaranteed. Moreover, there is no manufacturer at home and abroad that can produce this low-alloy hig...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/04C22C33/04C21D8/02
Inventor 杨东朱书成许少普张立新崔冠军康文举唐郑磊李红洋张涛徐昭庞林朱先兴
Owner NANYANG HANYE SPECIAL STEEL CO LTD
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