Process for producing high strength hardened and tempered steel by steekle mill on-line quenching

A furnace coil rolling mill, high-strength technology, applied in the direction of rolling mill control device, metal rolling, manufacturing tools, etc., can solve the problems of high production cost, low output, long production process cycle, etc., to achieve low cost, short product flow, The effect of improving the accuracy of shape control

Active Publication Date: 2009-01-28
NANJING IRON & STEEL CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The disadvantages of this process are: it takes about 3 hours for each steel plate to be heated, and the output is very low; the running speed of the steel plate during quenching is 6-12 meters per minute, and the production process cycle is long; the investment in the quenching unit of the heat treatment furnace is 300 million yuan. The production cost is increased by 800-1200 yuan per ton of steel plate, and the production cost is high

Method used

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  • Process for producing high strength hardened and tempered steel by steekle mill on-line quenching
  • Process for producing high strength hardened and tempered steel by steekle mill on-line quenching
  • Process for producing high strength hardened and tempered steel by steekle mill on-line quenching

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Embodiment 1

[0029] The process of producing high-strength quenched and tempered steel by on-line quenching in a steckel mill includes the following processes:

[0030] (1) Billet heating: billet is cold loaded, the temperature in the preheating section is 600°C, the temperature in the heating section is 1180°C, the temperature in the soaking section is 1210°C, the total heating time is 8min / cm, and the holding time in the soaking section is 30min, which is convenient for the billet to be heated to The structure of the austenite zone is homogenized, and at the same time, the surface of the billet is prevented from being over-oxidized. The tapping temperature is 1200°C;

[0031] (2) Initial descaling with high-pressure water: the water pressure is 18Mpa to ensure the removal of the primary iron oxide scale produced during the heating process on the surface of the hot billet;

[0032] (3) Controlled rolling: In the first stage of controlled rolling, the single-pass reduction rate is 10%, the...

Embodiment 2

[0036] The process of producing high-strength quenched and tempered steel by on-line quenching in a steckel mill includes the following processes:

[0037] (1) Billet heating: before preheating the billet, the billet is warmed at 400°C, the temperature of the preheating section is 500°C, the temperature of the heating section is 1200°C, the temperature of the soaking section is 1190°C, and the total heating time is 10min / cm, of which the soaking section holding time 30 minutes, it is convenient for the steel billet to be heated to the austenite zone to homogenize the structure, and at the same time prevent the surface of the billet from over-oxidation, the tapping temperature is 1200 °C;

[0038] (2) Initial descaling with high-pressure water: water pressure ≥ 18Mpa, to ensure the removal of the primary iron oxide scale produced during the heating process on the surface of the hot billet;

[0039](3) Controlled rolling: In the first stage of controlled rolling, the single-pass...

Embodiment 3

[0043] The process of producing high-strength quenched and tempered steel by on-line quenching in a steckel mill includes the following processes:

[0044] (1) Billet heating: before billet preheating, the billet is warmed at 300°C, the temperature of the preheating section is 400°C, the temperature of the heating section is 1220°C, the temperature of the soaking section is 1210°C, and the total heating time is 12min / cm, of which the soaking section holding time 30 minutes, it is convenient for the steel billet to be heated to the austenite zone to homogenize the structure, and at the same time prevent the surface of the billet from overoxidation, the tapping temperature is 1210°C;

[0045] (2) Initial descaling with high-pressure water: water pressure ≥ 18Mpa, to ensure the removal of the primary iron oxide scale produced during the heating process on the surface of the hot billet;

[0046] (3) Controlled rolling: In the first stage of controlled rolling, the single-pass redu...

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Abstract

The invention relates to a production technology of high-strength quenched and tempered steel, in particular to a technology for the online quenching production of the high-strength quenched and tempered steel by using a steckel mill, comprising the following procedures of: (1) billet heating: temperature in a preheating section is less than or equal to 600 DEG C, and the temperature in a heating section is between 1220 DEG C and 1180 DEG C; (2) primary scale removal of high pressure water: the water pressure is more than or equal to 18Mpa; (3) controlled rolling: during the controlled rolling of a first stage, single path draft is more than or equal to 10 percent to 15 percent, and the total draft is more than or equal to 50 percent; during the controlled rolling of a second stage, steel rolling is carried out below recrystallization temperature, and the draft is controlled to be between 40 to 70 percent; (4) online quenching by using HACC; (5) offline tempering: the tempering temperature is between 550 to 670 DEG C, and the heat preservation time is 2 to 6min / mm. The technology for the online quenching and self-tempering production of the high-strength quenched and tempered steel by using the steckel mill can improve the production efficiency by dozens of times, lower the cost, not only reduce the reheating energy consumption, but also reduce the water resource consumption of offline quenching, and reduce investment on a quenching machine set.

Description

technical field [0001] The invention relates to a production process of high-strength quenched and tempered steel, in particular to a process for producing high-strength quenched and tempered steel by on-line quenching in a steel coil mill. Background technique [0002] High-strength quenched and tempered steel plates are classified according to their uses: quenched and tempered steel plates for high-strength pressure vessels (petroleum strategic storage tanks), high-strength engineering machinery steels, high-strength hull structure steels, and steel for crude oil transportation tanks for railway trains and pressure steel pipes for hydropower stations. The demand is also great. At present, a large number of high-strength quenched and tempered steel plates still need to be imported from abroad. [0003] At present, the production process of high-strength quenched and tempered steel mostly adopts the process of "hot rolling + off-line quenching + off-line tempering" for produ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/18B21B37/00B21B37/76
Inventor 黄一新祝瑞荣龚云芳王道远郭怀兵霍松波
Owner NANJING IRON & STEEL CO LTD
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