JP2552792B2 - Method for controlling heating of metallic steel strip by strip flame burner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating control method for a metal steel strip using a strip flame burner.

[0002]

2. Description of the Related Art A tandem rolling mill uses SUS304,
In order to prevent work hardening of cold-rolled metastable austenitic stainless steel such as SUS301, in Japanese Patent Laid-Open No. 63-10009, a heating device with a belt-shaped flame burner is provided on the inlet side of a tandem rolling mill to provide stainless steel. It is disclosed that the steel strip is heated and then subjected to warm tandem rolling.

[0003]

The heating control method of the strip flame burner for heating the metal steel strip as described above has the following problems. Generally, in the heating control method in which the number of strip flame burners is changed according to the transport speed, when the number of burners is increased, the fuel gas pressure decreases and it takes time until the burner is ignited. Be uniform.

[0004]

In order to solve the above problems, the present invention provides a plurality of strip-shaped flame burners arranged in the longitudinal direction of the metal steel strip, and the number of ignition of the strip-shaped flame burner according to the transport speed of the metal steel strip. Also, in the metal steel strip heating control method for changing the fuel gas flow rate to the band flame burner, when changing the number of ignitions of the band flame burner, the fuel gas flow rate control valve is set to the opening corresponding to the changed number of burner ignitions. After adjusting to, the number of burner ignition is changed.

[0005]

According to the present invention, a plurality of belt-shaped flame burners are arranged in the longitudinal direction of the metal steel strip, and the fuel gas flow rate control valve is provided when increasing the transport speed of the metal steel strip, that is, when increasing the number of burners. By adjusting the opening degree after the increase and increasing the number of burner ignitions, the burner is ignited quickly, the heating temperature of the metal steel strip becomes constant, and the product characteristics become uniform.

[0006]

1 is a schematic view of a heating apparatus for a stainless steel strip showing an embodiment of the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a plan view thereof and a piping system diagram. In the figure, reference numeral 1 is a stainless steel strip, 2 is a support roll, and 3 is a heating device wall. Four
Is the outer wall of the heating device. Reference numeral 5 is a strip flame burner, 6 is a combustion flame formed by the strip flame burner, 7 is a fuel gas supply pipe, 8 is a combustion air supply pipe, 9 is a combustion air supply fan, 10 is a fuel gas cutoff valve, 11 Is a fuel gas flow rate control valve.

The strip-shaped flame burner 5 is provided above the stainless steel strip 1 in order to uniformly heat the stainless steel strip 1 from above and below.
Books, five at the bottom are fixed to the outer wall 4 of the heating device by bolts. The strip-shaped flame burner 5 is installed at a right angle to the stainless steel strip 1 and jets fuel gas and combustion air to form a uniform flame 6 in the width direction of the stainless steel strip. To heat.

When the transport speed of the stainless steel strip 1 is changed, the fuel gas cutoff valve 10 is opened / closed according to the transport speed in order to keep the temperature of the stainless steel strip 1 on the heating device outlet side within a certain range. Thus, control is performed by extinguishing the band-shaped flame burner 5 by a point. That is, a heating control method is performed in which many belt-shaped flame burners 5 are ignited when the transport speed is fast, and the number of ignitions is reduced when the transport speed is slow.

FIG. 6 is a control system diagram of the embodiment. The control device 13 is supplied with the transport speed (line speed) of the stainless steel strip, and the number of ignitions of the burner 5 is determined according to this transport speed. Then, corresponding to the result, each fuel gas cutoff valve 10 is operated (ON-OFF). On the other hand, FIG.
As shown in, the opening degree of the fuel gas flow rate control valve 11 is determined according to the number of burner ignitions, and the set opening degree of the fuel gas flow rate control valve 11 is changed in advance in accordance with this. In this way, when the change of the set number of burners and the set opening degree of the flow rate adjusting valve 11 due to the change of the conveying speed is completed, thereafter, the fuel gas flow meter 14, the fuel gas flow rate controller 15,
Normal PID control is performed by the loop of the fuel gas flow rate control valve 11.

4 and 5, the heating device outlet steel strip temperature, fuel flow rate, fuel flow rate adjustment when heating control is performed when the conveying speed of the stainless steel strip 1 is increased using the heating device having the above-described structure It shows the valve opening, the number of burner ignitions, and the transfer speed.
FIG. 4 shows the control by the normal PID controller fuel flow rate control, and FIG. 5 shows the result of using the control for setting the fuel gas flow rate control valve to a predetermined opening when increasing the number of ignitions of the strip flame burner according to the present invention. is there. When the transport speed is increased, the number of burner ignition is changed from 6 to 8. The shaded line 22 is the number of strip flame burners that are actually ignited, and the solid line 23 is the number that issues an ignition command to the strip flame burners. In the control by the normal PID controller fuel flow rate control shown in FIG. 4, when the number of open fuel gas cutoff valves 10 is increased in order to increase the number of burners by increasing the conveying speed as shown by the curve 21, the curve 25 The fuel flow rate for each burner is temporarily decreased as shown by, and then the fuel gas flow rate control valve 11 is opened by PID control as shown by the curve 24, and the fuel flow rate for each burner becomes a combustible flow rate and ignition is performed. To do. In such control, the temperature of the steel strip on the outlet side of the heating device with respect to the conveying speed due to ignition fluctuates greatly as shown by the curve 26.

Therefore, as shown in FIG. 5, when the number of ignitions of the belt flame burner is increased (curves 32, 33, 34) according to the change of the conveying speed (curve 31), the fuel gas flow rate control valve is changed to the curve 35. As shown by, the opening of the fuel gas flow control valve 11 is set so that the fuel flow rate for each burner ignited by the number of burners that are temporarily issuing the ignition command to the strip flame burner becomes a combustible flow rate. (Curve 36) eliminates the ignition delay of the burner and the temperature of the steel strip on the outlet side of the heating device (curve 3)
7) could be kept uniform.

[0012]

As described above, according to the present invention, when a plurality of strip-shaped flame burners are arranged in the longitudinal direction of the metal steel strip and the number of ignition of the strip-shaped flame burner is increased according to the transport speed of the metal steel strip. By using the metal steel strip heating temperature control to set the fuel gas flow rate control valve to an opening corresponding to the number of burner ignitions, uniform heating in the longitudinal direction of the metal steel strip became possible.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a device of the present invention.

FIG. 2 is a front view of FIG.

3 is a plan view and a piping system diagram of FIG. 1. FIG.

FIG. 4 is a graph of a conventional steel strip temperature of a heating device, a fuel flow rate for each burner, a fuel flow control valve opening, a number of burner ignitions, and a conveying speed.

FIG. 5 is a graph showing the temperature of the steel strip on the outlet side of the heating device of the embodiment, the fuel flow rate for each burner, the fuel flow control valve opening, the number of burner ignitions, and the transfer speed.

FIG. 6 is a control system diagram.

FIG. 7 is a graph showing the relationship between the number of burners and the fuel gas flow valve opening.

[Explanation of symbols]

1 Stainless Steel Strip 2 Support Roll 3 Heating Device Wall 4 Heating Device Outer Wall 5 Belt Flame Burner 6 Combustion Flame 7 Fuel Gas Supply Pipe 8 Combustion Air Supply Pipe 9 Combustion Air Supply Fan 10 Fuel Gas Cutoff Valve 11 Fuel Gas Flow Control Valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ichiko Sanbontake, 1st Kawasaki-cho, Chuo-ku, Chiba City, Kawasaki Steel Co., Ltd. Chiba Steel Works (72) Hidenori Miyake 1 Kawasaki-cho, Chuo-ku, Chiba City Kawasaki Steel Stock company Chiba Works (56) Reference JP-A-2-112818 (JP, A)

Claims (1)

(57) [Claims] 1. A metal steel strip in which a plurality of strip flame burners are arranged in the longitudinal direction of the metal strip, and the number of ignitions of the strip flame burner and the fuel gas flow rate to the strip flame burner are changed according to the transport speed of the metal strip. In the heating control method, when changing the number of ignitions of the belt-shaped flame burner, the fuel gas flow rate control valve is adjusted to an opening degree corresponding to the number of burners after the change of the number of burner ignitions, and then the number of ignitions of the burner is changed. Method for controlling heating of metal steel strip by a strip flame burner.