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Cooling method for fine control over microstructure of hot-rolled strip steel

A technology of microstructure and fine control, applied in the field of steel rolling, can solve the problems of uneven distribution of the microstructure of the strip, increased residual stress of the strip, and color difference on the surface of the strip, so as to make up for the lack of cooling capacity, the structure and performance of the strip. Homogenizes, eliminates the effect of low temperature on the upper surface

Active Publication Date: 2021-06-29
德龙钢铁有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The uneven temperature distribution of the width and thickness of the strip leads to the uneven distribution of the microstructure of the strip, and at the same time, the uneven distribution of the hardness and scale thickness of the strip, and the color difference on the surface of the strip, and the residual color inside the strip. increased stress

Method used

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  • Cooling method for fine control over microstructure of hot-rolled strip steel
  • Cooling method for fine control over microstructure of hot-rolled strip steel
  • Cooling method for fine control over microstructure of hot-rolled strip steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0063] Example 1: 1250mm steel strip production line rolling DC04 steel grade, strip steel thickness 3.0mm, width 1050mm, finish rolling temperature 890°C, finish rolling speed 600m / min, laminar flow cooling adopts sparse cooling with 1 row of cooling water pipes at intervals mode, the coiling temperature is controlled at 600°C, after the strip is cooled by laminar flow, it enters the first zone of the fan for forced air cooling, and then enters the first coiler for coiling. Basic parameters of the fan: the maximum air volume is 19000m 3 / h, maximum wind pressure 700Pa, diameter 700mm, wheelbase 1.8m (distance between adjacent fans). The parameters of wide band D of side baffle opening and fan air volume F are determined as follows:

[0064] D=(0.085×W strip )×10-10

[0065] =(0.085×1050)×10-10

[0066] =882.5(mm)

[0067] F=(T strip × v finish ×D)×100

[0068] =(3.0×600×882.5)×100×10 -6 ×60

[0069] =9531(m 3 / h)

[0070] The test results show that the grain size ...

Embodiment 2

[0073] Example 2: A 1780mm strip steel production line rolled 700L automobile frame steel, with a thickness of 8.0mm, a width of 1500mm, a finish rolling temperature of 850°C, and a finish rolling speed of 200m / min. Laminar cooling adopts dense cooling + sparse cooling mode with one row of cooling water pipes in each group, and the coiling temperature is controlled at 650°C. After laminar flow cooling, the strip enters the fan zone 1 and the fan zone 2 for forced air cooling, and then enters the second coiler for coiling. Basic parameters of the fan: the maximum air volume is 19000m 3 / h, the maximum wind pressure is 700Pa, and the wheelbase is 1.8m. The parameters of side baffle opening width D and fan air volume F are determined as follows:

[0074] D=(0.065×W strip )×10-10

[0075] =(0.065×1500)×10-10

[0076] =965(mm)

[0077] F=(T strip × v finish ×D)×100

[0078] =(8×200×965)×100×10 -6 ×60

[0079] =9264(m 3 / h)

[0080] Embodiment 2 can find out that strip ...

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Abstract

The invention discloses a cooling method for fine control over a microstructure of hot-rolled strip steel. The cooling method comprises a laminar cooling procedure, a strip steel coiling procedure and a forced air cooling procedure, and the forced air cooling procedure is composed of a first fan area arranged between the laminar cooling procedure and a first coiling machine and a second fan area arranged between the first coiling machine and a second coiling machine. 4-6 axial flow fans are arranged in the first fan area, 2-3 axial flow fans are arranged in the second fan area, all the axial flow fans are located below a roller way and conduct forced air cooling on strip steel running on the upper portions of the axial flow fans, all the axial flow fans are provided with forced air width adjusting devices, and the opening width and the air volume of side baffles of the forced air width adjusting devices are adjusted according to the strip steel of different specifications. According to the cooling method for fine control over the microstructure of the hot-rolled strip steel, through forced air cooling and adjustment of the opening width of the side baffles in an air duct, the cooling speed state in the width direction of the strip steel can be adjusted, the structure of an oxide scale on the surface of the strip steel is controlled, and the thickness of the oxide scale is reduced; and chromatic aberration of the middle and the edges of the strip steel is improved and eliminated.

Description

technical field [0001] The invention relates to a steel rolling technology, in particular to a cooling method for finely controlling the microstructure of hot-rolled strip steel. Background technique [0002] Conventional hot-rolled strip production cooling process such as Figure 4 shown. Laminar cooling 19 is a cooling control device arranged between the finishing unit 18 and coiling in the hot strip mill. It is mainly composed of an upper spray device, a lower spray device, a side spray device and a control valve group. The temperature of the strip is to ensure the structure and performance of the strip. Since the first set of laminar flow cooling system was applied to the production of hot-rolled strip steel, the post-rolling control cooling technology has developed rapidly: one is the development of process technology, which is reflected in the progress of cooling technology and laminar flow cooling device; the other is the improvement of control technology Developmen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21B37/24B21B37/46B21B37/74B21C47/02
CPCB21B37/74B21B37/46B21B37/24B21C47/02
Inventor 牛跃威杨志刚朱云杰陈四平黄伟丽徐子谦东根来王信威陈娟豆艳苹张海朝易耀云陈红霞
Owner 德龙钢铁有限公司