Hot rolled strip surface processing method

A hot-rolled steel strip and surface treatment technology, applied in the field of metallurgy, can solve the problems that natural cooling cannot meet the requirements, increase equipment investment, lack of systematic research on the thickness of tertiary oxide scale and structure, etc., to ensure surface quality and mechanical properties, The effect of increasing investment and production costs and compensating for the loss of mechanical properties

Inactive Publication Date: 2018-03-13
王刚
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, there are many measures to clean the oxide scale on the surface of the steel plate, but most of the methods remove the furnace oxide scale, the primary oxide scale and the secondary iron oxide before finishing rolling, and how to control the thickness and structure of the tertiary scale, which affects the quality of the steel surface There is still a lack of systematic research on key issues
The technology disclosed in Japanese Patent (Patent No. 06-033449) requires the cooling speed of the hot-rolled coil to be above 1°C / s in order to obtain dense iron oxide scale. Natural cooling cannot meet the requirements, which requires the use of industrial fans and water cooling spray. shower cooling, increased equipment investment
In addition, the structure of iron oxide scale in this technology is Fe 3 o 4 - FeO- Fe 3 o 4 Three-layer structure, the steel plate obtained in this way is in the occasion of deep processing, the adhesion of the oxide scale has yet to be verified

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Heating the slab to 1220°C, keeping it warm for 120 minutes, and then descaling, the descaling temperature is 1100°C;

[0017] The descaled slab is subjected to rough rolling, the starting rolling temperature is 1150°C, the final rolling temperature is 950°C, and the cumulative reduction is 75%. After rough rolling, hot coiling is carried out at 1000°C to obtain an intermediate billet;

[0018] The intermediate billet is subjected to secondary descaling with high-pressure water, and the temperature of the secondary descaling is 1100°C; then, it is subjected to finish rolling, with the starting temperature of the finish rolling being 1020°C, the finishing rolling temperature being 870°C, and the cumulative rolling reduction of the finish rolling being 80% ;

[0019] After finishing rolling, it is cooled to 500°C at a rate of 10°C / s, then coiled, and the surface treatment is completed. Fe 3 o 4 The content of 75%.

Embodiment 2

[0021] Heating the slab to 1240°C, keeping it warm for 90 minutes, and then descaling, the descaling temperature is 1150°C;

[0022] The descaled slab is subjected to rough rolling, the starting rolling temperature is 1200°C, the final rolling temperature is 1000°C, and the cumulative reduction is 76%. After rough rolling, hot coiling is carried out at 1050°C to obtain an intermediate billet;

[0023] The intermediate billet is subjected to secondary descaling with high-pressure water, and the temperature of the secondary descaling is 1200°C; then, it is subjected to finish rolling, with the starting temperature of the finish rolling being 1030°C, the finishing rolling temperature being 880°C, and the cumulative rolling reduction of the finish rolling being 85% ;

[0024] After finishing rolling, it is cooled to 510°C at a rate of 11°C / s, then coiled, and the surface treatment is completed. Fe 3 o 4 The content of 76%.

Embodiment 3

[0026] Heating the slab to 1250°C, keeping it warm for 60 minutes, and then descaling, the descaling temperature is 1200°C;

[0027] The descaled slab is subjected to rough rolling, the starting rolling temperature is 1250°C, the final rolling temperature is 1100°C, and the cumulative reduction is 77%. After rough rolling, hot coiling is carried out at 1100°C to obtain an intermediate billet;

[0028] The intermediate billet is subjected to secondary descaling with high-pressure water, and the temperature of the second descaling is 1300°C; then it is subjected to finish rolling, with the start temperature of finish rolling being 1040°C, the finishing rolling temperature being 900°C, and the cumulative rolling reduction of finish rolling being 90% ;

[0029] After finishing rolling, it is cooled to 520°C at a rate of 12°C / s, then coiled, and the surface treatment is completed. Fe 3 o 4 The content of 77%.

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Abstract

A surface treatment method for hot-rolled steel strips, which is carried out in the following steps: (1) heating the slab to 1220-1250 ° C, descaling after heat preservation; (2) rough rolling, the cumulative reduction is 75-77%, Hot coiling at 1000~1100°C to obtain the intermediate billet; (3) second descaling, the temperature is 1100~1300°C; then finish rolling, the cumulative reduction of finish rolling is 80~90%; (4) with 10~ Cool at a speed of 12°C/s to 500~520°C, and then coil. The process of the present invention can effectively reduce FeO fragmentation during the rolling process, avoid the subsequent generation of red scale, and at the same time effectively reduce the thickness of scale, and finally realize the flexible production of scale control.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, in particular to a surface treatment method for hot-rolled strip steel. Background technique [0002] At present, there are many measures to clean the oxide scale on the surface of the steel plate, but most of the methods remove the furnace oxide scale, primary oxide scale and secondary iron oxide before finishing rolling, and how to control the thickness and structure of the third scale scale, which affects the quality of the steel surface There is still a lack of systematic research on key issues. The technology disclosed in Japanese patent (Patent No. 06-033449) requires the cooling speed of the hot-rolled coil to be above 1°C / s in order to obtain dense iron oxide scale. Natural cooling cannot meet the requirements, which requires industrial fans and water-cooled spray Shower cooling increases equipment investment. In addition, the structure of iron oxide scale in this technology is Fe 3...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21B37/74B21B1/22B21B45/08C22C38/04C22C38/06C22C38/02C22C38/12
CPCB21B37/74B21B1/22B21B45/08B21B2001/225C22C38/02C22C38/04C22C38/06C22C38/12
Inventor 王刚
Owner 王刚
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