JPH01306097A - Detection of weld zone in steel hoop - Google Patents

Abstract

PURPOSE:To eliminate false detections and to reduce failures by providing a means to detect a conveying capacity of steel hoop, a means to detect changed parts of magnetic resistance and a means to detect holes formed on a weld zone of the steel hoop. CONSTITUTION:A pulse oscillator 8 is provided on a carrying roll 7, a hole 3 is formed near a detection instrument of conveying capacity of steel hoop 1 and a weld zone 2 of steel hoop 1, hole sensors 4 are equipped on the upper and the lower part of steel hoop 1 and a magnetic sensor 5 is equipped at a position far by a specified distance L1 from the hole sensor 4 and facing the steel hoop 1. When one of a part of change of the magnetic resistance and the hole 3 is detected and then the other is detected in the range of a fixed conveying capacity, a detection signal of the weld zone is inputted. Consequently, even when a hole defect is found in the midst of steel hoop 1, real weld zone can be discriminated. False detection does not break out in spite of false composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for reliably detecting welding points on a continuously conveyed belt.

[Background of the invention]

In a process line for continuously conveying steel strips, it is very important to accurately detect the joints (welding points) between steel strips in order to perform various controls.

The following methods (1) to (5) are known as typical conventional methods for detecting weld points on steel strips. Of these, (1) ~ (
3) is a simple method that does not use a computer, (4),
(5) is a method using a computer.

(kl, ?8) A hole with a diameter of about 20mm is made near the contact point, and a photoelectric switch (hole sensor) is installed in the upper and lower parts of the steel strip passing through the welding point detection position, which is a combination of a light emitting part and a light receiving part. A method of detecting the above hole and considering it as a welding point.

(2) Two holes with a diameter of approximately 20 squares are drilled at a predetermined interval near the welding point, and the distance between the holes is determined by an optical image sensor installed in the same manner as in (1) above. A method of identifying a hole for the purpose of welding point detection and considering it as a welding point.

(3) A method in which a magnetic sensor is installed at the welding point detection position so as to face the belt, and a change in the composition of the metal is detected by detecting a change in the eddy current perturbation resistance, and this is determined to be a welding point.

(4), the above-mentioned
A method in which a detection signal is compared with an integrated value in combination with any of the sensors according to (1) to (3), and when the integrated value is within a - constant error range, a welding point is determined.

(5) When the total length of the steel strip can be used as a known value before fat feeding, using the previous welding point detection as the starting point.

A method of determining the welding point by subtracting the conveyance amount from the total length.

[Problem to be solved by the invention]

However, each of the above conventional methods has the following problems.

Since the hole sensor (1) also detects hole defects in the steel strip, it may be difficult to distinguish between a true welding point (hole) and a hole defect using the hole sensor alone.

(2) The method for determining using the optical system image sensor is 2.
It cannot be used if it is difficult to drill holes at predetermined intervals. Furthermore, if there is a change in the pass line due to a defect in the shape of the steel strip, etc., it becomes difficult to install and adjust it for accurate detection.

If there is a compositional defect in the middle of the steel strip, the magnetic sensor (3) detects this, so it may be difficult to distinguish it from a true welding point. Further, as in the case of optical image sensors, if there is a change in the pass line due to a defect in the shape of the steel strip, etc., it becomes difficult to adjust the mounting position.

In the method using the combination of the conveyance amount of the steel strip (4) and the above-mentioned sensor, if there are multiple hole defects or shape defects before and after the welding point of the steel strip, the welding point detection signal will be the same as that of the welding point multiple times at - period. A signal is generated that may have an adverse effect on a control device that uses the detected signal.

The method (5) of subtracting the conveyance amount from the known total length of the steel strip cannot be used if the total length of the strip is unknown or cannot be used even if it is known.

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 detecting a welding point of a steel strip, which eliminates all the problems of the conventional methods as described above.

[Means to solve the problem]

To this end, the present invention provides means for detecting the amount of conveyance of the steel strip;
A means for detecting a part of the steel strip where the magnetic resistance changes, and a means for detecting a hole formed near the welded part are provided, and after detecting either the part of the magnetic resistance change or the hole, a predetermined It is determined whether or not the other one is detected within the range of the conveyance amount, and the detection signal of the welded portion is output based on the determination that the other one is detected.

〔Example〕

Hereinafter, a method for detecting a welding point of a steel strip according to the present invention will be explained. FIG. 1 is an explanatory diagram showing an overview of the detection method of the present invention. In this figure, 1 is a steel strip that is conveyed (threaded) in the direction of the arrow, 2 is a welding point of the steel strip, and 3 is a hole formed near the welding point 2.

Reference numeral 4 denotes a hole sensor consisting of a combination of a light emitting part 41 and a light receiving part 42 which are arranged opposite to each other in the upper and lower parts of the steel strip 1 being conveyed, and 5 denotes a distance from the hole sensor 4 in the conveying direction of the steel strip 1. L
, are magnetic sensors installed so as to face the rope belt 1 at positions far apart from each other. Reference numeral 6 indicates a position further away from the magnetic sensor 5 by a distance L2 in the conveying direction of the steel strip 1, and when the welding point 2 reaches this position, a signal for detecting the welding point is output from a computer to be described later.

Here, the distance from welding point 2 to hole 3 is L:l, and the maximum value of the variation error of this distance L3 is L4, and the above hole sensor is adjusted so that the relationship between these and Ll and Lz satisfies the following equation. 4 and the positions of the magnetic sensor 5 are set.

(Ll +LZ) > (L3 +L4)
(117 is a conveyance roller that rotates following the conveyance of the rope rope 1, 8 is a pulse oscillator attached to the conveyance roller rough, and the pulse oscillator 8 rotates in synchronization with the conveyance roller 7 to generate pulses. The amount of conveyance (distance) of the steel strip 1 is detected by converting the count value of this pulse. Note that the method of detecting the amount of conveyance is not limited to this, and there are various methods.

FIG. 2 is a block diagram of a computer that inputs and processes signals from the hole sensor 4, magnetic sensor 5, and pulse oscillator 8 and outputs a welding point detection signal.

Between the cores, signals from the hole sensor 4 and magnetic sensor 5 are passed through the interrupt input circuit 9, and signals from the pulse oscillator 8 are passed through the pulse input circuit 10 to the digital switch 1.
The distance data L I-I-4 preset in 1 is input to each CPU l 3 via the digital input circuit 12.
It is now being incorporated into the Here, L3 is provided with a symbol to represent the positional relationship between the welding point 2 and the hole 3.

That is, as shown in Fig. 1, when the hole 3 is on the opposite side of the welding point 2 to the conveying direction of the steel strip 1, it is marked as "+", and when it is on the conveying direction side, or when either case is possible, it is marked as "-". 14 is a digital output circuit connected to the output side of the CPU 3.

CPUI 3 has a built-in program consisting of the following steps. 3 to 7 are flowcharts of the program. FIG. 3 is a flowchart showing the entire process, which is composed of steps 81 to S9. 8
2 to S5 are determination steps, and 36 to S9 are processing steps branched from these determination steps. Details of each processing step 86 to S9 are shown in FIGS. 4 to 7.

The meanings of the symbols used in these float charts are as follows.

Fl: Detection interrupt from hole sensor 4 'IJF2:
'IJF3' when there is a detection interrupt from magnetic sensor 5: 'IJF3' when checking after detecting hole sensor 4 'IJF4: '1' when checking after detecting +11 air sensor 5 F5: '1' when there is a welding point F6: Welding point detection signal "1" during post-output suppression, then the first
An outline of steps 81 to S9 shown in the figure will be described. In step S1, before starting the program, information used in steps 82 to S9 below is initialized. Note that the setting values in the figure are actual values performed in test examples described later.

In steps S2 and S6, it is determined whether or not there is an interruption of the detection signal of the hole sensor 4 or the magnetic sensor 5, and if there is an interruption, it is recorded which interruption occurred.S2
), when the process branches to step S6, it is determined whether or not it is necessary to perform a process for detecting a welding point.

In steps S3 and S7, a detection signal interrupt from either the hole sensor 4 or the magnetic sensor 5 is received (F3=1
or F4=1), the conveyance amount is determined within a certain period until a detection signal interrupt from the other sensor is accepted.

In steps S4 and S8, after detecting the welding point in step S6 (F5=1), it is determined whether or not the welding point has reached the position 6 where the detection signal is output. Outputs.

In steps S5 and S9, after outputting the detection signal in S8, the welding point detection function is suppressed by a constant one maximum distance (F6-1).

Step Sl is executed only once when the computer starts processing, and steps 82 to S9 are executed repeatedly thereafter. As a result, the welding point detection signal is outputted from the digital output circuit 14 to the outside.

Step S6, which is executed when there is a detection interruption from the hole sensor 4 or the magnetic sensor 5, is a program shown in the flowchart shown in FIG.

In step S61, it is determined whether welding point detection signal output processing is being executed (F5=1) or the welding point detection function is being suppressed (F6
=1), and if it is being suppressed or being executed, the process returns without performing the subsequent steps 862 to S66.

The reason for this determination is that when it is determined in the following processing step that there is a welding point, detection interrupts from each sensor are ignored thereafter. As a result, the welding point is detected only once in the vicinity of the welding point.

In step S62, the cumulative value up to now (current cumulative value:
This is the integrated value from the time when there is the first detection interruption from either the hole sensor 4 or the magnetic sensor 6, and the corresponding distance is LN. ) plus the count value of the number of pulses that count the pulses taken in from the pulse oscillator 8 (previous integrated value, corresponding distance measurement) is stored in another integrated memory. Then, the pulse counter and the current integrated value are cleared to zero.

This zero clearing process functions as a calculation function for determining a certain period in the process of step S7 described above. Total value. In the transcription, when the current detection interrupt is a signal from the hole sensor 4 and it is determined that there is a welding point, the remaining length from the detection of the magnetic sensor 5 to the welding point detection signal output position 6 is calculated. do it for the sake of

In step S63, it is determined whether the detection of melting in the stainless steel tube S2 is the first sensor detection or the subsequent sensor detection. That is, if either the hole sensor 4 or the magnetic sensor 5 is detected first, the process proceeds to step S67, and if the other sensor is detected later, it is determined that a welding point exists and the process proceeds to step S6.
Proceed to step 4.

In step 364, the distance to the welding point presence detection signal output position 6 (
Lx) is determined from the digital switch setting value L2 and the previous integrated value (1, , ).

In other words, the sensor detected later is hole sensor 4 (Fl-1).
If , r-x = Lz-L,
・The sensor detected after 121 is magnetic sensor 5 (F
1≠1), Lx”Lz (3).

In step S65, there was a welding point (F5-1)
remember. This is required to carry out the subsequent processing steps and is also used for the determination in step S4 described above.

In step S66, the memory of the sensor detected later is canceled. This is done because it is no longer needed due to the determination that there is a welding point.

In step S67, it is determined based on the digital switch setting values L1, L, , L, whether there is a possibility of subsequent sensor detection, depending on the type of sensor detected first. That is, the sensor that first detected is hole sensor 4 (
F1=1), then L+ −L:l +L4 >O
...(4) If magnetic sensor 5 (F≠1), l
L:ll 14. +L, >0...
- As for (5), if equation (4) or (5) is satisfied, it is determined that there is a possibility and the next step 368 is executed, but if there is no possibility, the process returns as is.

In step S68, it is stored that the sensor that detected first has already been detected. This is necessary for executing the next processing step, and is also used for the determination of steps S63 and S3 described above when there is a detection interruption of a sensor detected later.

Next, the process of step S7 is executed by the program shown in the flowchart of FIG. In step S71, the value of the pulse counter indicating the transport amount is read and the current integrated value (L
H) and the integrated value from the time of first sensor detection (
Ls) is obtained, and then the pulse counter is cleared to zero.

In step S72, the digital switch setting value L+
, Lz, L4 and the current integrated value (LH) to determine whether the welding point has passed through the check range.

In this check range, the first sensor detected is hole sensor 4. (F3=1) If LI L3 + L4 < LN − (61 Magnetic sensor 5 (F3≠1) then L L3 + L4 L, < LN...(
7), and if the above formula (6) or (7) is satisfied, it is determined that the check range has passed and the process proceeds to the next step S7.
Execute step 3 and return if not satisfied.

In step S73, the memory of the first detected sensor being detected is canceled. This means that there was a detection interrupt from one of the sensors, but the check range was exceeded (there was no detection interrupt from the other sensor within the check range).
This means that it was not determined to be a welding point.

Next, the process of step S8 is executed by the program shown in the flowchart of FIG. In step S81, the value of the pulse counter is read and added to the current integrated value (LH), and the pulse counter is cleared to zero. The obtained integrated value (LN) indicates the distance from the sensor detected later.

In step S82, the distance from the current integrated value is determined.

It is determined whether or not the welding point detection signal output position 6 has been reached based on the LX obtained in step S64 of the program described above.

LH>LX (8) If this formula (8) is satisfied, it is determined that it has been reached and the next steps 383 to 386 are executed, and if not satisfied, the process returns.

In step S83, a welding point detection signal is outputted via the digital output circuit 14.

In step S84, the memory of the existence of welding points processed in step S65 is canceled. This is because the role of the memory has been completed by outputting the welding point detection signal.

In step 385, the pulse counter and the current integrated value (L
Clear H) to zero. This acts as a cancellation process for checking for a certain period in steps S5 and S9.

In step S86, it is further stored that the detection function needs to be suppressed for a certain period of time.

Finally, the process of step S9 is executed by the program shown in the flowchart of FIG. Ste/knob S91 reads the value of the pulse counter and calculates the current integrated value (t,,i
) and clear the corresponding pulse counter to zero. The obtained integrated value (1,,+) is a value corresponding to the distance from the welding point detection signal output position 6.

In step S92, the current integrated value (LH) and the suppression distance (
It is determined whether or not it has reached outside the suppression range.

L,>Li...If (8) is satisfied, it is determined that it has been reached and the next step S93 is executed, and if not satisfied, the process returns.

In step S93, the storage in step S86 is canceled. This completes the processing step, and when there is a detection interruption from the hole sensor 4 or magnetic sensor 5 again, the function of determining the presence or absence of a welding point is restored in step S2.

[Test example]

First, each setting value was set as follows.

I-+ = 25 (X 10wm) Lz = 30 (X 1 0ui) L:l = 3
0 (×1 0++m) L4=15 (XIO Dragon) Li=10 (X10m through) The LiO value depends on the actual situation near the welding point of the steel strip 1, but the above set value was sufficient. Further, LI to L4 are set and input using the digital switch 11, but in reality, they are set as program internal constants along with Li. Furthermore, the value taken in from the pulse oscillator 8 is that one pulse is 10
It was designed to have a steel strip conveyance of 11. As a result of conducting the experiment under the above conditions, there were no false positives, and stable operation was demonstrated.

〔Effect of the invention〕

From the above, the present invention has the following effects. ■.

Even if there is a hole defect in the middle of the steel strip, it can be determined from a true weld point. (2) Only one hole is required for detecting the welding point. ■There is no false detection due to changes in the pass line of the steel strip. (2) Compared to the case where a magnetic sensor is used alone, the adjustment is less rough, and even if there is a compositional defect, there is no false detection. (2) Even if there are multiple hole defects or shape defects before and after the welding point of the steel strip, the welding point will only be detected once. ■A simple and economical welding point detection device with few failures can be realized.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the state of use of an apparatus used in a detection method according to an embodiment of the present invention, FIG. 2 is a block diagram of a computer used in the detection method, and FIGS. 3 to 7 are diagrams showing the computer used in the detection method. 2 is a flowchart of a program incorporated in 1... Steel strip, 2... Welding point, 3... Hole, 4...
Hole sensor, 41... Light emitter, 42... Light receiver, 5 Magnetic sensor, 6... Welding point detection signal output position, 7...
Conveyance roller, 8 pulse transmitter. Agent Patent Attorney Tsuneaki Nagao Cause 1 Figure 2 Figure 3 Figure N4 Figure 6 Competition

Claims (1)

[Claims] (1) A method for detecting a weld between a leading material and a trailing material of a steel strip being conveyed, which includes means for detecting the amount of conveyance of the steel strip, and detecting a portion where magnetic resistance changes in the steel strip. and a means for detecting a hole formed near the welded portion, and after detecting either the magnetic resistance changing portion or the hole, the other is detected within a predetermined conveyance amount. A method for detecting a welded part of a steel strip, characterized in that the detection signal of the welded part is output based on the determination that the other one is detected.