JPH01219127A - Method for operating continuous annealing furnace - Google Patents

Abstract

PURPOSE:To adjust the iron loss value of an electrical steel sheet with high accuracy by measuring the iron loss value of the same part of the electrical steel sheet by a material thermometer on the outlet side of a heating zone and the iron loss meter on the outlet side of an annealing furnace and comparing the two measured values, then correcting the control of treatment conditions of the annealing furnace. CONSTITUTION:The material temp. of the electrical steel sheet 1 measured by the material thermometer 40 in the outlet of the heating zone 22 of the continuous annealing furnace 20 is inputted to an iron loss converter 60 and is converted to the data of the iron loss value which is then inputted to an automatic control device 50 and a memory device 70. The automatic control device 50 compares the set value from an iron loss setter 54 and the above- mentioned input value and outputs the regulation signal of the iron loss value to a line speed regulator 55. On the other hand, the same part of the electrical steel sheet 1 measured by the material thermometer 40 is measured by the iron loss meter 30 on the outlet side of the annealing furnace 20 and the result thereof is inputted to a relational computing element 80 which compares the measured iron loss and the data from the memory device 70 and inputs the correction signal to an iron loss converter 60. The automatic control device 50 corrects the control of the line speed regulator 55 in accordance with the correction signal. The iron loss value of the electrical steel sheet 1 is thereby adjusted with high accuracy and the productivity is greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of operating a continuous annealing furnace for adjusting the core loss value of electrical steel sheets.

[Prior art]

BACKGROUND ART Magnetic properties of electromagnetic steel sheets used as magnetic materials for electrical equipment, ie, core loss value, magnetic flux density, etc., are used as quality control indicators. Conventionally, such an index has been generally controlled based on the material temperature, that is, the temperature of the electrical steel sheet during annealing.

By the way, the temperature of the electrical steel sheet that is continuously sent out from the continuous annealing furnace, that is, the material temperature, is often measured using a radiation thermometer that uses thermal infrared rays, etc., but there are various problems when measuring this, such as the following. occurs.

(1) Emissivity fluctuates under the influence of scale that forms and adheres to electrical steel sheets in the furnace, causing errors in temperature measurement results.

(2) Atmosphere between the electromagnetic steel sheet and the thermometer (temperature, humidity,
(dust, etc.), the emissivity changes and errors occur in the temperature measurement results.

(3) Errors occur in temperature measurement results due to changes in the material of electrical steel sheets. That is, even if the temperature of the steel plate is the same, if the material is different, the emissivity will be different, resulting in an error in the temperature measurement result.

As a result, the iron loss value also deviates significantly from the target due to the inaccurate material temperature being measured, so in actual operation, the iron loss can be reduced by adjusting the material temperature to a slightly higher temperature and the line speed to a slightly slower value. The reality is that the target iron loss value is maintained by keeping the value low. For this reason, productivity cannot be improved, and it is difficult to say that it is preferable from the viewpoint of energy saving.

As a solution to this problem, in the radiation thermometer in the optical field such as the thermal infrared rays mentioned above, (1) Utilizing the multiple reflection effect within the cavity, (
2) Reflecting the radiation from two types of blackbody furnaces on the surface of the electromagnetic steel sheet, (3) Utilizing the multiple reflection effect due to specular reflection, (4)
Attempts have been made to find the true temperature by correcting the emissivity using a specular reflection cavity and an absorption cavity.

However, such a method has problems in maintainability because it is necessary to frequently change the temperature measurement direction of the measuring device between the direction of the cavity and the electrical steel sheet that is the actual temperature measurement target. In addition, the temperature measurement range is defined by the detection element used and is narrow, and methods (3) and (4) above require a relatively long measurement time of 20 to 60 seconds. There is a problem.

Therefore, as a solution to this problem, the present inventors installed an iron loss meter that detects the iron loss value of the electrical steel sheet on the outlet side of the continuous annealing furnace, and compared the detected value of the iron loss meter with the line of the continuous annealing furnace. The relationship between the line speed and speed is determined in advance for each constant furnace temperature as shown in FIG. 5, and the line speed of the continuous annealing furnace is controlled based on the relationship in order to make the iron loss value of the electrical steel sheet match the target value. We have previously proposed a method to do this (Japanese Patent Application No. 75222/1982).

[Problem to be solved by the invention]

However, even with the above-described method proposed by the present inventors, there are still problems to be solved. That is, even though it is clear that when adjusting the iron loss value of a magnetic steel sheet in a continuous annealing furnace, the iron loss value is determined by the material temperature on the heating zone exit side of the continuous annealing furnace, In the method described above, the iron loss meter is placed on the outlet side of the continuous annealing furnace, and since its position and the position on the outlet side of the heating zone are quite far apart (specifically, several tens of meters), the control described above is difficult. As a result, there is a problem that the iron loss value deviates from the target value as shown in FIG. Ta.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for solving the above-mentioned problems and adjusting the iron loss value of an electrical steel sheet with high precision.

[Means to solve the problem]

The operating method of a continuous annealing furnace according to the present invention includes disposing an iron loss meter for detecting the iron loss value of the electrical steel sheet on the outlet side of the continuous annealing furnace,
Based on the relationship between the detected value of the iron loss meter and the processing conditions of the continuous annealing furnace, the processing conditions are controlled to make the iron loss value of the electrical steel sheet match the target value, and the iron loss value of the electrical steel sheet is adjusted. In the operating method of a continuous annealing furnace, a material thermometer for measuring the temperature of the electrical steel sheet is arranged on the heating zone exit side of the continuous annealing furnace, and the iron loss value and its value are calculated from the measured value by the material thermometer. The method is characterized in that the control of the processing conditions is corrected using the result of comparing the iron loss value detected by the iron loss meter in correspondence with the measured portion.

[Effect]

In the method of the present invention, the iron loss value converted from the temperature of the electrical steel sheet measured with a material thermometer placed on the exit side of the heating furnace in the continuous annealing furnace, and the The iron loss value detected by the iron loss meter is compared with the iron loss value detected by the iron loss meter, and the comparison result is used to correct the control of processing conditions such as line speed.
The iron loss value of electrical steel sheets can be adjusted with high precision.

Furthermore, in order to obtain data for comparison, the material temperature measurement using the material temperature meter and the iron loss value detection using the iron loss meter include an iron loss value detection portion in the material temperature measurement portion of the electrical steel sheet. Since they are performed in correspondence with each other, even if the position of the material temperature meter and the position of the iron loss meter are far apart, the error due to the time difference can be eliminated, and the adjustment can be performed with higher precision.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof.

FIG. 1 is a schematic diagram showing the configuration of an apparatus for carrying out the method of operating a continuous annealing furnace according to the present invention, and FIG. 2 is a block diagram showing the configuration of the iron loss meter.

First, the configuration of the iron meter used in the present invention will be explained with reference to FIG.

Iron loss refers to the power consumed by a steel plate when the steel plate is magnetized with alternating current, and its measurement method is specified by JIS. That is, the sample steel plate was excited with an alternating current of 5011z, and the maximum magnetic flux density within the steel plate was set to 15 kGaus.
Power loss W per 1 kg of sample when s is
S... It is expressed in (W/kg). Note that r1515 old represents an iron loss of 50c/sec 15kGauss.

An iron loss meter for measuring this iron loss is, for example, the one shown in FIG. 2, which was previously proposed by the applicant of the present invention in Japanese Patent Application No. 119269/1983. Its specific configuration is as follows.

In the figure, numeral 1 indicates an electrical steel sheet being transported in the longitudinal direction on a production line (not shown).

In the transfer area of the electromagnetic steel sheet 1, excitation coils 2.3 having an inner diameter slightly larger than the widthwise dimension of the electromagnetic steel sheet 1 are provided at two positions spaced apart by a suitable length in the transfer direction. The electromagnetic steel sheet 1 is transferred through this excitation coil 2.3, and both ends of each of the excitation coils 2 and 3 are JI
It is connected to an AC power source 5 of 501Iz (60Hz may also be used) specified by S.

Therefore, when the electromagnetic steel sheet 1 is transferred through the excitation coils 2.3, it is AC magnetized by the excitation coils 2, 3 in the longitudinal direction thereof.

A detection coil 4 is installed approximately in the center between the excitation coils 2 and 3 so as to wrap around the electromagnetic n-plate 1. This detection coil 4 has a frequency of 5011z based on the frequency of the AC power supply 5.
harmonics of 100 Hz or more caused by waveform distortion caused by core loss of the electromagnetic steel sheet 1.

and a discontinuous movement phenomenon of the internal domain wall of the electromagnetic steel sheet 1 during the steel sheet magnetization process, in other words, outputs a signal containing a mixture of three components of known Barkhausen noise.The signal output by the detection coil 4 is generated by the current control circuit 6 and the electric power. A total of 7 are given.

Current control circuit 6 controls the intensity of the magnetic field generated from excitation coil 2.3 by controlling the output current of AC power supply 5 based on the signal given from detection coil 4.

On the other hand, the wattmeter 7 is supplied with an excitation current from the AC power supply 5 in addition to the signal from the detection coil 4 described above. Therefore, the wattmeter 7 detects the power loss from both and provides the result to the iron loss detection circuit 8.

In addition, 9 and 10 in the figure are a thickness detector and a width detector, respectively, which are installed facing the electromagnetic steel sheet 1 between the excitation coils 2 and 3, and detect the displacement of the thickness and width of the electromagnetic steel sheet 1. is applied to the iron loss detection circuit 8.

The iron loss detection circuit 8 detects the displacement detection values of the thickness and width of the electromagnetic steel sheet 1 given from the thickness detector 9 and the width detector 10, the signal value input from the wattmeter 7, and the electromagnetic steel sheet l given in advance. Standard thickness 1 width.

The iron loss value W is calculated from the density etc. using the following formula and output.

W=P/ρ・w−f However, ρ: Density of steel plate t: Thickness of steel plate W: Width of steel plate l: Effective magnetic path length Note that the effective magnetic path length l is effective as a detection target for iron loss value W. This refers to the range of the electromagnetic steel sheet 1 that is magnetized, and the density ρ of the steel sheet, the thickness t of the steel sheet, the width W of the steel sheet, etc. are also values within the range of this effective magnetic path length l.

The method of the present invention is carried out by using an iron loss meter basically constructed as described above together with a material temperature meter to be described later, and the overall apparatus configuration will be explained below with reference to FIG.

In the figure, 20 is a continuous annealing furnace, and the non-oxidation furnaces 21. A heating zone 22°, a soaking zone 23 and a cooling zone 24 are arranged continuously.

The non-oxidizing furnace 21 heats the electromagnetic steel sheet 1 from both sides with direct burners inside the furnace 21 to burn and remove rolling oil adhering to the surface of the electromagnetic copper sheet 1. The burner combustion at this time is performed at an air-fuel ratio of about 0.9, and the atmosphere in the furnace is made non-oxidizing (weakly oxidizing), and the electrical steel sheet 1 is heated while being prevented from excessive oxidation.

The heating zone 22 heats the electromagnetic steel sheet l from both the front and back sides using a radiant tube. The inside of this heating zone 22 is a reducing gas atmosphere sent from a cooling zone 24 to be described later, and the thin oxide film on the surface of the electrical steel sheet 1 generated in the non-oxidation furnace 21 is reduced.

The soaking zone 23 soaks the electromagnetic steel sheet l to make its crystal grain size sufficiently thick (thereby improving the magnetic properties. For this reason, the soaking zone 23 takes a sufficient soaking time for the electromagnetic steel sheet l. That's what I do.

The cooling zone 24 cools the electrical steel sheet 1 to 150° C. while reducing the electromagnetic steel sheet 1 with a reducing atmosphere gas. In addition, this cooling zone 2
AX gas (Ht nia: 5%, N2: 25%) obtained by thermally decomposing ammonia is normally used as the reducing atmosphere gas in 4.

A material temperature gauge 40 for measuring the temperature of the electrical steel sheet 1, that is, the material temperature, is disposed on the exit side of the heating zone 22 of the continuous annealing furnace 20, and the aforementioned iron loss meter 30 is disposed on the exit side of the furnace. Note that the material thermometer 40 that measures the material temperature on the exit side of the heating zone 22 includes:
A microwave radiometer is used to simultaneously measure the brightness temperature and emissivity in the microwave band, and the true temperature is determined by compensating for emissivity fluctuations (for example, Japanese Patent Laid-Open No. 61-288130
It is recommended to use the following. If such a material thermometer is used, emissivity measurement is easy, and temperature measurement over a wide range is possible without requiring mechanical movement of the device.

Further, in the figure, 42 is a payoff reel around which the electromagnetic steel sheet 1 to be processed in the continuous annealing furnace 20 is wound. It passes through a continuous annealing furnace 20 equipped with a thermometer 40 and an iron loss meter 30 disposed on the outlet side thereof, and is wound onto a tension reel 45.

The line speed adjustment roll 51 has a line speed adjustment device 55.
A pulse generator 53 is connected to the motor 52, and the pulse generator 53 provides the automatic control device 50 with a number of pulses corresponding to the number of rotations of the motor 52. It has become. The automatic control device 50 also includes an iron loss setting device 54 that sets an iron loss value, and converts the material temperature measured by the material thermometer 40 into an iron loss value according to the material of the electrical steel sheet 1. A signal from an iron loss converter 60, which receives a comparison signal as described later, is also input.

Note that the information regarding the iron loss value converted by the iron loss converter 60 is taken into the storage device 70, where it is stored for an appropriate time and then input to the comparator 80.

Further, information regarding the iron loss value detected by the iron loss meter 30 is also input to the comparison calculator 80,
The comparison calculator 80 compares and contrasts the input information.

The comparison signal is then input to the iron loss converter 60.

When implementing the method of the present invention using such a device, a desired iron loss value is input and set to the automatic control device 50 by the iron member setting device 54. Then, based on a command from the automatic control device 50, the line speed adjustment device 55 is activated to first adjust the line speed.

Then, a material temperature gauge 40 on the exit side of the heating zone 22 of the continuous annealing furnace 20
The measured value of material temperature measured by
For example, the data is converted into iron loss value data based on the correlation shown in FIG.

Then, in the automatic control device 50 to which the signal is input, the signal is compared with the set value input by the iron loss setting device 54 as described above, and the difference is determined by the iron loss setting device 55. Output as a loss value adjustment signal.

On the other hand, the iron loss value of the electrical steel sheet 1 after passing through the continuous annealing furnace 20 is actually measured by an iron loss meter 30 on the outlet side of the continuous annealing furnace 20.

Then, the measured data is manually inputted to the storage device 70, where it is stored for an appropriate period of time (specifically, when the electromagnetic steel sheet 1 is
0 position to the position of the iron loss meter 30) is compared in the comparison calculator 80 with the data regarding the converted value which is stored and input to the comparison calculator 80, and the signal regarding the result is The signal is input to the iron loss converter 60 as a correction signal.

In this way, if the data of the converted value and the data of the actual value regarding the iron loss value are compared using the storage device 70, the electrical steel sheet l moves from the position of the material temperature gauge 40 to the position of the iron loss meter 30. Errors based on the time difference corresponding to the time taken up to the point can be eliminated, and both data can be appropriately compared to obtain an appropriate correction signal.

The result of adjusting the iron loss value of the electromagnetic steel sheet 1 using the appropriate correction signal thus obtained is illustrated in FIG. I understand.

In addition, in the above embodiment, the iron loss value of the electromagnetic steel sheet 1 was adjusted by adjusting the line speed, but the method of the present invention can also be applied when adjusting the iron loss value of the electromagnetic steel sheet 1 depending on the furnace temperature. Applicable.

〔effect〕

As described above, according to the present invention, when manufacturing electrical steel sheets, problems such as iron loss value greatly deviating from the target value due to errors in material temperature measurement, resulting in waste, or problems such as increasing the material temperature or It is also possible to adopt an operation mode that attempts to maintain the iron loss value below the minimum target value by maintaining the line speed at a low level, thereby significantly improving productivity.

Then, when adjusting the iron Ti value of the electrical steel sheet, we compared the data converted from the material temperature actually measured at the heating zone outlet side of the continuous annealing furnace with the data of the iron loss value actually measured at the continuous annealing furnace outlet side. Since the adjustment is carried out while eliminating errors due to differences, highly accurate adjustment is possible.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the configuration of an apparatus for implementing the method of the present invention, Fig. 2 is a block diagram showing the configuration of an iron loss meter used therein, and Fig. 3 is a schematic diagram showing the configuration of an iron loss meter used for implementing the method of the present invention. A graph showing the correlation between the side material temperature and iron loss value. Figure 4 is a graph showing the actual measurement data of the rust repair adjusted by the method of the present invention. Figure 5 is a graph showing the line speed and line speed used when implementing the conventional method. A graph showing the correlation with the iron loss value, FIG. 6 is a graph showing actually measured data of the iron loss value adjusted by the conventional method. 1...Electromagnetic steel sheet 20...Continuous annealing furnace 22...
Heating zone 30...1 iron member total 40...Material thermometer 50.
...Automatic control device 60...Iron loss converter 70...Storage device 80...Comparison calculation equipment license Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono
Husband 7007501K) O850900950 heating belt, 10,000 yen! ('e) Ear 3 Diagram Δ , q II'I(m") ji0) 75 30 'Is 4Q 45rai>i reception
(yl/yu, ■) 纂 5 times

Claims (1)

[Claims] 1. An iron loss meter is placed on the outlet side of the continuous annealing furnace to detect the iron loss value of the electromagnetic steel sheet. Based on the relationship between the detected value of the iron loss meter and the processing conditions of the continuous annealing furnace, the In a method for operating a continuous annealing furnace in which the iron loss value of an electrical steel sheet is adjusted by controlling the processing conditions to make the iron loss value match the target value,
A material thermometer for measuring the temperature of the electrical steel sheet is arranged on the heating zone exit side of the continuous annealing furnace, and the iron loss value is calculated based on the iron loss value converted from the measured value by the material thermometer and the iron loss value corresponding to the measured portion. A method for operating a continuous annealing furnace, characterized in that the control of the processing conditions is corrected using the result of comparing the iron loss value detected by a meter.