KR100983762B1 - Method for continuously manufacturing cold-rolled steel - Google Patents

Abstract

A continuous manufacturing method of cold rolled steel comprises the steps of: providing a coil of white steel 100 produced by hot rolling the cast steel after annealing and pickling the cast steel; Uncoiling and welding the coil 100 of the white steel in the uncoiling-welding facility 21 to form a flattened and welded steel strip 400; Passing the flattened and welded steel strip 400 through a cold rolling device 23 for cold rolling the steel strip 400 to make a first strip accumulator 22 and a cold rolled steel having a predetermined thickness; And cold rolled steel, degreasing device 24, second strip accumulator 25, annealing-pickling facility 26, third strip accumulator 27, temper rolling device 28, tension leveling device ( 29), sequentially processing using the fourth strip accumulator 31 and the trimming-recoiling facility 32.

Description

Continuous manufacturing method of cold rolled steel {METHOD FOR CONTINUOUSLY MANUFACTURING COLD-ROLLED STEEL}

The present invention relates to a continuous production method of cold rolled steel, and more particularly, to a method for continuously producing cold rolled steel from white steel.

Conventional methods of manufacturing stainless steel essentially include casting, hot rolling and cold rolling. The steel slab obtained from the casting is hot rolled to obtain a black steel coil, which is annealed and pickled to obtain a white steel coil. The white steel coil may be further processed by cold rolling, annealing, pickling, temper rolling, tension leveling, or the like to obtain a steel coil product. Products obtained by cold rolling, annealing and pickling are known as 2D steel coils and products obtained by further temper rolling and tension leveling the 2D steel coils are known as 2B steel coils.

Referring to FIG. 1, a conventional cold rolled steel manufacturing method includes a steel coil preparation facility 11, a cold rolling facility 12, an annealing-pickling facility 13, a temper rolling facility 14, and a tension leveling facility ( It is carried out using a multistage fabrication line comprising 15), wherein the facilities are separated from each other.

The steel coil preparation facility 11 is used to loosen the white steel coil 100 into a white steel strip 400, after which the white steel strip 400 is welded with a guide part 8 to 10 meters long at each end. It is wound by the steel coil 200. The steel coil 200 is conveyed to the cold rolling facility 12.

The steel coil 200 is unwound into the steel strip 400, which passes through the cold rolling mill 12. The cold rolling facility 12 is a 20-high cold rolling mill and is used to cold roll the steel strip 400 to have a predetermined thickness. The steel strip 400 after cold rolling is wound by the steel coil 200, and the steel coil 200 is conveyed to the annealing pickling facility 13.

The steel coil 200 is unwound into the steel strip 400 and the steel strip 400 passes through the annealing pickling fixture 13, in which the steel strip 400 is annealed after being annealed. Pickled to remove scale from 400. After pickling the steel strip 400 is wound into the steel coil 200, which is a 2D steel coil.

The 2D steel coil 200 may be further conveyed to the temper rolling facility 14. The steel coil 200 is unwound into the steel strip 400, and the steel strip 400 passes through the temper rolling facility 14. The temper rolling equipment 14 is used to polish the steel strip 400. After the temper rolling, the steel strip 400 is wound into the steel coil 200, and the steel coil 200 is conveyed to the tension leveling facility 15.

The steel coil 200 is unwound into the steel strip 400, the steel strip 400 passes through the tension leveling facility 15, which is trimmed and wound up after the steel strip 400 is tension leveled in the tension leveling facility 15. To obtain steel coil product 300 (ie, 2B steel coil).

Since the facilities 11, 12, 13, 14, 15 for performing the conventional cold rolled steel manufacturing method are separated from each other, a plurality of packaging operations such as an intermediate winding operation and a coil from one installation to another installation Delivery is necessary. In addition, the cost of energy consumption is high due to the multiple operations of conveying intermediate products (coils) between the installations. In addition, storage space for intermediate products is required.

In order to overcome the above-mentioned disadvantages encountered in conventional multistage production lines, it is desired in the art to develop continuous production lines for the production of cold rolled steel.

U.S. Patent No. 6,478,899 discloses a method and apparatus for manufacturing cold rolled stainless steel strips, which produce cold rolled stainless strips from liquid metal directly to the thin strip casting, i.e. from the casting step to the finishing step to packaging the coiled strip. The entire process step consists of running the process continuously on a single production line. However, since the methods and equipment disclosed in this document start with casting stainless steel strips directly from liquid metal, the associated work units and steps are relatively complex. Thus, the techniques disclosed in this document are impractical for use in the industry.

U. S. Patent No. 6,546, 771 discloses a method for making strips of stainless steel, which comprises rolling in the cold state of strips which are produced or hot rolled through strip casting in a preceding process. Depending on the various specific requirements of the final product, the stainless steel must pass through the rolling mill line once or twice. In addition, a rolling mill line or part thereof may be used in a process aimed at the production of strips having various characteristics which are of considerable importance for certain applications. The utilization of the rolling mill line is relatively low because part of the rolling mill line has to be stopped in consideration of specific requirements for the final product.

Therefore, there is still a need in the art to provide an improved method for continuously producing cold rolled steel.

It is therefore an object of the present invention to provide a method for continuously producing cold rolled steel in order to solve the above-mentioned drawbacks of the prior art.

Therefore, the continuous manufacturing method of the cold rolled steel of this invention contains the following steps.

Providing a coil of white steel (100) produced by annealing and pickling after hot rolling of cast steel;

Uncoil and weld the white steel coil 100 in an uncoiling-welding installation 21, while flattening the white steel coil 100 in an uncoiling device 211 and welding device 212. Welding to form a flattened and welded steel strip 400;

Passing the flattened welded steel strip (400) through a set of tension rollers (221) provided in a first strip accumulator (22);

Moving the steel strip 400 from the first strip accumulator 22 to a cold rolling apparatus 23 for cold rolling the steel strip 400 to produce cold rolled steel having a predetermined thickness;
Moving the cold rolled steel from the cold rolling device 23 to a degreasing device 24 for removing grease from the cold rolled steel strip 400;

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Moving the cold rolled steel from the degreasing apparatus 24 toward the second strip accumulator 25 having a set of tension rollers 251;

Cold rolled steel from second strip accumulator 25 to annealing-pickling facility 26 for annealing the cold rolled steel and annealing the cold rolled steel after annealing to remove scale from the cold rolled steel. Moving;

Moving the cold rolled steel from the annealing pickling facility 26 toward a third strip accumulator 27 having a set of tension rollers 271;

The cold rolled steel is moved from the third strip accumulator 27 to a temper rolling device 28 for glossing the cold rolled steel, which is different from other devices. Which can be stopped independently;

Moving the cold rolled steel from the tempered rolling device 28 toward a tension leveling device 29 for leveling the cold rolled steel;

Moving the cold rolled steel from the tension leveling device 29 toward the fourth strip accumulator 31 having a set of tension rollers 311; And

Moving the cold rolled steel from the fourth strip accumulator (31) to a trimming-recoiling installation (32) for trimming and recoiling the cold rolled steel.

Other features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments with reference to the accompanying drawings.

2, a preferred embodiment of the continuous production method of cold rolled steel according to the present invention includes the following steps.

1) providing a coil of white steel:

A coil 100 of white steel is provided which is produced by annealing and pickling after hot rolling a cast steel.

2) Uncoiling and Welding Steps:

The coil of white steel 100 is unwound and welded in the uncoiling-welding installation 21, where the coil of white steel 100 is flattened in the uncoiling apparatus 211 and welded in the welding apparatus 212 to produce a steel strip 400. ). The uncoiling apparatus 211 includes two overhang-mandrel type uncoilers. The welding device 212 comprises a first arc welder for welding steel strips having a thickness of at least 1.5 mm, preferably 1.5-6 mm, and a second arc welder for welding steel strips having a thickness of less than 1.5 mm. It includes.

3) passing through the first strip accumulator:

The flattened and welded steel strip 400 is passed through a set of tension rollers 221 provided in the first strip accumulator 22.

4) Cold Rolling Steps:

The steel strip 400 is cold rolled from the first strip accumulator 22 to the cold rolling apparatus 23 for making cold rolled steel having a predetermined thickness. The cold rolling apparatus 23 includes three cold rolling mills 231 arranged in series. The steel strip 400 is cold rolled to a rolling ratio in the range of 50 to 70% and a thickness of 0.3 mm. The thickness when the steel strip 400 enters the cold rolling mill 23 is measured. Automatic gauge control to measure the thickness and shape of the steel strip 400 as it exits the cold rolling mill 23, and to monitor the state of the cold rolling mill 23 and the properties of the steel strip 400 after cold rolling. Transfer to the shape control system.

5) Degreasing step:

The cold rolled steel from the cold rolling apparatus 23 is moved toward the degreasing apparatus 24 for removing grease from the cold rolled steel strip 400. The degreasing device 24 includes a base solution spraying zone 241 for spraying a base solution on cold rolled steel, a water washing zone 242 for cleaning cold rolled steel using water, and drying the cold rolled steel after washing. A drying area 243 for.

6) moving the cold rolled steel toward the second strip accumulator:

The cold rolled steel is moved from the degreasing device 24 to the second strip accumulator 25. The second strip accumulator 25 is similar in structure to the first strip accumulator 22 and has a set of tension rollers 251.

7) Annealing and Pickling Steps:

Annealing-pickling facility 26 for electrolyzing and acid cleaning cold rolled steel after annealing the cold rolled steel from the second strip accumulator 25 to anneal the cold rolled steel and descale it in the cold rolled steel. Move to). Annealing-pickling facility 26 includes annealing device 261 and pickling device 262. Annealing device 261 is characterized by heating zone 263 operating at a temperature in the range of 1000 ° C. to 1200 ° C. and cold rolling steel by radiant heat generated upstream of heating zone 263. A preheating region 264 to preheat, and a cooling region 265 disposed downstream of the heating region 263 to cool the cold rolled steel to a temperature no higher than 80 ° C. The pickling device 262 includes an electrolysis tank 266 containing a sodium sulfate solution for removing iron oxide scale from cold rolled steel, and nitric acid and hydrofluoric acid for removing the Fe—Cr—Ni oxide scale from the cold rolled steel. And an acid washing tank 267 for accommodating water, and a water washing region 268 for washing cold rolled steel.

8) moving the cold rolled steel towards the third strip accumulator:

The cold rolled steel is moved from the annealing-pickling facility 26 toward the third strip accumulator 27. The third strip accumulator 27 is similar in structure to the first strip accumulator 22 and has a set of tension rollers 271.

9) Temper Rolling Steps:

The cold rolled steel is moved from the third strip accumulator 27 to the temper rolling device 28 for glossing the cold rolled steel. The temper rolling device 28 includes a set of work rolls (ash rolls) 281 for glossing the cold rolled steel via transfer printing.

10) Tension Leveling Steps:

The cold rolled steel is moved from the temper rolling device 28 to the tension leveling device 29 for leveling the cold rolled steel. The tension leveling device 29 includes a leveling unit 291 for leveling cold rolled steel, and a wash drying device 292 for washing and drying the cold rolled steel after leveling. The leveling unit 291 includes a set of bending rolls 293 and a set of reverse bending rolls 294. Further, before the cold rolled steel enters the leveling unit 291, water or lubricant is sprayed on the cold rolled steel by the washing and drying apparatus 292.

11) moving the cold rolled steel to the fourth strip accumulator:

The cold rolled steel is moved from the tension leveling device 29 toward the fourth strip accumulator 31. The fourth strip accumulator 31 is similar in structure to the first strip accumulator 22 and includes a set of tension rollers 311.

Each of the first, second, third and fourth strip accumulators 22, 25, 27, 31 adjusts the tension of the steel and allows the speed at which the steel moves through two adjacent devices to be independent of each other. Note that there is.

12) moving the cold rolled steel to a trimming-recoiling plant:

The cold rolled steel is moved from the fourth strip accumulator 31 toward the trimming-recoiling plant 32. The trimming-recoiling equipment 32 includes a trimming device 321 for trimming cold rolled steel and a recoil for recoiling cold rolled steel to obtain a cold rolled steel product 300 (ie, a 2B steel coil). Ring device 322.

In addition, in the case of manufacturing a 2D steel coil, it can be obtained by simply stopping the operation of the temper rolling device 28. Thus, the utilization of the production line for carrying out the method of the present invention can be improved over the prior art.

Referring to Figure 3, the cold rolled steel products produced by the method of the present invention and the cold rolled steel products produced by the conventional multi-stage process shown in Figure 1, equipment costs, labor costs, operating speed, throughput, productivity, And in terms of total production cost. As shown in Fig. 3, although the equipment cost of the method of the present invention is relatively high and the operation speed of the method of the present invention is relatively low, the labor cost, throughput, and productivity of the method of the present invention are reduced to that of the conventional multi-stage process. Compared to the above. In total, the total production cost of the process of the present invention is only 78% of conventional multistage processes.

While the present invention has been described in terms of what is considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments and that the various arrangements within the spirit and scope of the broadest interpretation are intended to encompass all such modifications and equivalents. It is intended to be included.

1 is a schematic diagram of a conventional cold rolled steel manufacturing method performed using a multi-stage fabrication line,

2 is a schematic diagram of a preferred embodiment of a method for continuously producing cold rolled steel according to the present invention;

3 is a bar graph illustrating a comparison of manufacturing efficiency of a preferred embodiment of the prior art of FIG.

Claims (8)

In the continuous production method of cold rolled steel, Providing a coil of white steel (100) produced by annealing and pickling after hot rolling of cast steel; Uncoil and weld the white steel coil 100 in an uncoiling-welding installation 21, while flattening the white steel coil 100 in an uncoiling device 211 and welding device 212. Welding to form a flattened and welded steel strip 400; Passing the flattened welded steel strip (400) through a set of tension rollers (221) provided in a first strip accumulator (22); Moving the steel strip 400 from the first strip accumulator 22 to a cold rolling apparatus 23 for cold rolling the steel strip 400 to produce cold rolled steel having a predetermined thickness; Moving the cold rolled steel from the cold rolling device 23 to a degreasing device 24 for removing grease from the cold rolled steel strip 400; Moving the cold rolled steel from the degreasing apparatus 24 toward the second strip accumulator 25 having a set of tension rollers 251; Cold rolled steel from second strip accumulator 25 to annealing-pickling facility 26 for annealing the cold rolled steel and annealing the cold rolled steel after annealing to remove scale from the cold rolled steel. Moving; Moving the cold rolled steel from the annealing pickling facility 26 toward a third strip accumulator 27 having a set of tension rollers 271; The cold rolled steel is moved from the third strip accumulator 27 to a temper rolling device 28 for glossing the cold rolled steel, which is different from other devices. Which can be stopped independently; Moving the cold rolled steel from the tempered rolling device 28 toward a tension leveling device 29 for leveling the cold rolled steel; Moving the cold rolled steel from the tension leveling device 29 toward the fourth strip accumulator 31 having a set of tension rollers 311; And Moving the cold rolled steel from the fourth strip accumulator 31 to a trimming-recoiling installation 32 for trimming and recoiling the cold rolled steel, 2D cold rolled steel can be produced by stopping the temper rolling device 28 independently of the other devices. Continuous production method of cold rolled steel. The method of claim 1, The steel strip 400 is cold rolled to a thickness of 0.3 mm at a rolling ratio in the range of 50 to 70%. Continuous production method of cold rolled steel. The method of claim 1, The degreasing device 24 includes a base solution spraying region 241 for spraying a base solution on cold rolled steel, a water washing region 242 for washing cold rolled steel with water, and a cold rolled steel after washing with water. Comprising a dry area 243 Continuous production method of cold rolled steel. The method of claim 1, The annealing-pickling facility 26 includes an annealing device 261, which comprises a heating zone 263 operating at a temperature in the range of 1000 ° C. to 1200 ° C., and upstream of the heating zone 263. And a preheating zone 264 arranged to preheat the cold rolled steel by the radiant heat generated by the heating zone 263, and a cold rolled steel disposed downstream of the heating zone 264 to a temperature of 80 ° C. or less. Comprising a cooling zone 265 for cooling Continuous production method of cold rolled steel. The method of claim 1, The uncoiling device 211 includes two overhang-mandrel type uncoilers. Continuous production method of cold rolled steel. The method of claim 1, The welding device 212 includes a first arc welder for welding steel strips having a thickness of at least 1.5 mm and a second arc welder for welding steel strips with a thickness of less than 1.5 mm. Continuous production method of cold rolled steel. The method of claim 1, The annealing-pickling facility 26 includes a pickling device 262, which comprises an electrolysis tank 266 containing sodium sulfate for removing iron oxide scale from cold rolled steel, and cold rolling An acid wash tank 267 containing nitric acid and hydrofluoric acid for removing the Fe—Cr—Ni oxide scale from the steel; and a flushing area 268 for washing cold rolled steel. Continuous production method of cold rolled steel. The method of claim 1, The tension leveling device 29 includes a washing drying device 292 for washing and drying cold rolled steel after leveling. Continuous production method of cold rolled steel.

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