JP3056424B2 - Temper rolling method and equipment for steel sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for temper rolling a steel sheet.

[0002]

2. Description of the Related Art In a process line such as a continuous annealing line for a steel sheet, from the viewpoint of surface quality assurance, a flaw on the steel sheet surface is detected online by a visual inspection by an inspector or an automatic inspection by an automatic surface inspection apparatus, and immediately. There is a system in which feedback is made upstream to eliminate the cause of occurrence. In recent years, an automatic surface inspection apparatus is often used due to the advantage of moving point detection performance in addition to labor saving.

[0003] On the other hand, in the upstream of the automatic surface inspection apparatus on the exit side of the process line, temper rolling is performed to ensure the flatness of the steel sheet. As shown in FIG. 3, this is performed using, for example, a 6-layer temper rolling mill in which a work roll (WR), an intermediate roll (IMR), and a backup roll (BUR) are arranged vertically. A foreign substance called dull powder is generated and causes a surface flaw called a roll mark on the steel plate 20.
24, spraying a conditioning liquid (mineral oil frequently used for lubrication, cleaning, etc.) to the engagement between the steel plate 20 and the work roll, and an air wiper 18 Dull powder is removed by a temper rolling method of air-wiping a used temper liquid by injection.

However, in this method, the used refining liquid is not sufficiently removed, and as shown in FIG.
On the surface of the liquid (called liquid residue). If there is such a liquid residue, the automatic surface inspection apparatus may erroneously recognize this as a surface flaw depending on the size and contrast, and may issue a detection alarm to disrupt the process. If the injection amount of the refining liquid is reduced to avoid this, a roll mark is generated.

[0005] Therefore, a temper rolling method that does not use a temper liquid, for example, a dry skin pass method as shown in FIG. 5 has been considered. This is a method in which the roll polishing is performed by the roll polisher 23 and the generated dust powder is sucked, and there is no liquid residue on the surface of the steel plate 20. Roll marks frequently occur because the washing of the mill (rolling machine) that has been performed at any time using the liquid material cannot be performed.

As described above, according to the conventional technique, there is a problem that it is difficult to eliminate the roll mark if the automatic surface inspection apparatus tries to eliminate erroneous recognition.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, suppress the occurrence of roll marks in a process line, and furthermore, the automatic surface inspection apparatus tends to erroneously recognize the remaining liquid. It is an object of the present invention to provide a method and a facility for temper rolling of a steel sheet that can prevent the occurrence.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a method for injecting pure water into a steel sheet during temper rolling of a steel sheet, and more preferably, injecting a temper solution instead of pure water when stopping temper rolling, and thereafter, A temper rolling method for a steel sheet, characterized in that the steel sheet is forcibly dried. In the present invention, it is further preferable that the steel sheet is air-wiped after temper rolling and before forced drying.

Further, the present invention provides a temper rolling mill for steel sheets,
An injection nozzle capable of injecting a liquid to the inlet side of the temper rolling mill, a liquid switching device capable of selectively supplying pure water and a tempering liquid to the injection nozzle, and a pure water and a tempering liquid respectively supplied to the liquid switching device. An air wiper comprising a pure water tank and a temper liquid tank that can be supplied, and a steel sheet dryer disposed downstream of the temper rolling mill, and preferably further capable of air wiping the steel sheet between the temper rolling mill and the steel sheet dryer. And a temper rolling facility comprising:

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Conventionally, a temper solution was jetted during temper rolling, whereas in the present invention, pure water was jetted. The inventors have conducted extensive studies and experiments, sprayed a tempering liquid at the time of temper rolling to remove dull powder, forcibly dried the steel sheet after temper rolling and evaporated the liquid residue on the surface, An important finding was that the content of the refining liquid remained as traces on the steel plate, but such traces did not remain when pure water was used. That is, according to the present invention made on the basis of such knowledge, there is no liquid residue on the steel sheet surface after the temper rolling, and the problem that the automatic surface inspection device mistakenly recognizes this as a surface flaw is solved.

However, when the temper rolling mill must be stopped due to a line trouble or the like, there is a high possibility that rust is generated by pure water riding on the steel plate stopped around the temper rolling mill. Therefore, at this time, it is preferable to switch to a refining liquid that normally also contains a rust-preventive component and spray it. The purity of the pure water is desirably about 99% or more, but it is sufficient that the content of the pure water does not remain when the plate surface is dried.

In mill cleaning, pure water may be used as in normal temper rolling, but the flow rate may be higher than that in normal temper rolling in order to increase cleaning efficiency. FIG. 1 is an overall conceptual diagram of a process line suitable for carrying out the present invention. A steel plate 20 is subjected to processing such as pickling, annealing, and plating by a processing facility (not shown) on the right side of FIG. Is sent to the temper rolling mill 2 and the material and shape are adjusted. At the same time as the temper rolling, pure water is sprayed onto the steel sheet, preferably simultaneously on the roll, to remove dull powder. The tempered rolled steel sheet 20 is sent to a steel sheet dryer 3 such as a hot air dryer or an electric heat dryer, where it is forcibly dried to remove pure water remaining on the surface by evaporation, and then passes through the automatic surface inspection device 5. Then, it is inspected for surface flaws. As described above, since the pure water does not leave any trace after the steel plate 20 is dried, the automatic surface inspection device 5 can correctly detect only the surface flaw. Thereafter, the steel sheet 20 passes by the driver's cab 6 of the line, passes through the oiler 7 and the shear 8 sequentially, and is wound up by the tension reels 9 and 9a.

FIG. 2 is a diagram showing a pure water supply system according to the temper rolling equipment of the present invention. As shown in FIG. 2, on the entry side of the temper rolling mill 2, an injection nozzle 17 that injects liquid mainly to a biting portion between the steel plate 20 and the work roll (WR) is arranged, and behind the injection nozzle 17. Is connected to the outlet of a three-way valve 16 that forms a liquid switching device, and the two inlets of the three-way valve 16 are pumps, respectively.
They are connected to a pure water tank 13 and a conditioning liquid tank 14 via 15 and 15a. The pure water tank 13 is supplied with pure water 11, and the refining liquid tank 14 is supplied with pure water 11a and refining liquid stock solution 12, respectively.

With this configuration, the pure water and the conditioning liquid can be freely switched and injected. Reference numerals 21 and 22 denote a drain pan and a drain pipe, respectively. In the same figure, the steel sheet 20 and the work roll (W
R) Air wiper 18 capable of air wiping the biting part with
Is shown. According to this, the drying load of the steel plate dryer 3 (see FIG. 1) is reduced, which is more preferable. It is also preferable to provide a drainage path such as a gutter in order to smoothly remove used pure water or conditioning liquid.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is applied to a continuous annealing line for annealing an automotive steel sheet having a thickness of 0.5 to 2.3 mm and a width of 700 to 1850 mm while passing the steel sheet at a maximum speed of 500 mpm.
It is applied in the form as shown in FIG. 2, and the injection flow rate of pure water is
2.43 l / min upper and lower at the injection nozzle header flow setting
The speed was set to 3.60 l / min, and the steel plate dryer was operated using a hot air dryer at a hot air temperature of 100 ° C and a hot air injection speed of 100 m / s.

As a result, as compared with the conventional method in which only the refining liquid is jetted, the ratio of direct shipment without passing through the refining line from the process line is improved by 7%, and the basic unit of the refining liquid is increased. However, when pure water was used, a remarkable effect of reducing 98% and reducing the frequency of roll mark occurrence by 60% was obtained.

[0017]

According to the present invention, there is an excellent effect that the occurrence of roll marks can be suppressed in the process line of a steel sheet and the occurrence of liquid residue can be prevented, thereby preventing the automatic surface inspection apparatus from erroneously recognizing.

[Brief description of the drawings]

FIG. 1 is an overall conceptual diagram of a process line suitable for carrying out the present invention.

FIG. 2 is a diagram of a pure water supply system according to the temper rolling equipment of the present invention.

FIG. 3 is an explanatory view of a conventional conditioning liquid injection system.

FIG. 4 is an explanatory diagram of a form of a liquid residue.

FIG. 5 is an explanatory diagram of a conventional dry skin pass method.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 Outgoing looper 2 Temper rolling mill 3 Steel plate dryer 5 Automatic surface inspection device 6 Operator's cab 7 Oiler 8 Shear 9, 9a Tension reel 11, 11a Pure water 12 Temper solution concentrate 13 Pure water tank 14 Temper solution tank 15 , 15a Pump 16 Three-way valve (liquid switching device) 17 Injection nozzle 18 Air wiper 20 Steel plate 21 Drain pan 22 Drain pipe 23 Roll polisher 24 Tempering liquid supply nozzle

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B21B 1/22 B21B 27/10 B21B 45/02

Claims (5)

(57) [Claims] 1. A method for temper rolling a steel sheet, wherein pure water is injected into the steel sheet during temper rolling of the steel sheet, and then the steel sheet is forcibly dried. 2. The temper rolling method for a steel sheet according to claim 1, wherein a temper solution is injected instead of pure water when the temper rolling is stopped. 3. The method according to claim 1, further comprising air wiping the steel sheet after temper rolling and before forced drying. 4. A temper rolling mill for a steel sheet, an injection nozzle capable of injecting a liquid to an inlet side of the temper rolling mill, a liquid switching device capable of selectively supplying pure water and a temper liquid to the injection nozzle, A steel plate conditioning system comprising a pure water tank and a conditioning liquid tank capable of supplying pure water and a conditioning liquid to the liquid switching device, respectively, and a steel sheet dryer disposed downstream of the temper rolling mill. Quality rolling equipment. 5. An air wiper capable of air wiping a steel sheet between a temper rolling mill and a steel sheet dryer.
Temper rolling equipment as described.