JP2000117442A - Method and device for submerged arc welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent defective welding by detecting the supply speeds of an electrode wire, averaging them for each fixed time, comparing the averaged speeds to an averaged speed signal precedent by one, judging no flux when a difference between both signals, has exceeded a prescribed value, outputting an abnormality signal and discontinuing welding. SOLUTION: An arc 2 is generated by supplying a welding power between an electrode wire 6 and an object 1 to be welded from a welding power supply 7 having a drooping characteristic and a constant current characteristic. The electrode wire 6 is supplied from wire supply rolls 3 by the rotation of a wire supply motor 4. The supply speed of the electrode wire 6, is detected as a wire supply speed detection signal Wd. The flux 11 of a hopper 10, is supplied from a nozzle 8. The wire supply speed detection signal Wd is received by a no-flux detection signal processing circuit 18, an averaged circuit output signal Vav within a fixed time, is calculated, and a difference ΔVav to a precedent output signal Vav, is calculated. When the difference ΔVav has exceeded a standard value Sr, an abnormality signal is outputted, and welding is discontinued.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submerged arc in which a flux is sprayed between a consumable electrode (hereinafter referred to as an electrode wire) and an object to be welded, and an arc discharge is generated in the sprayed flux to perform welding. The present invention relates to improvements in a welding method and apparatus.

[0002]

2. Description of the Related Art Conventionally, as a submerged arc welding method, a flux is sprayed on a welded portion,
By feeding the electrode wire into the scattered flux and performing arc discharge between the electrode wire and the workpiece,
The arc heat melts and joins the electrode wire and the workpiece. In addition, a part of the flux is melted by the arc heat to form slag, which has the effect of covering the molten metal and protecting it from the atmosphere. The slag also functions to help shape the bead when the molten metal solidifies.

First, before starting welding, a necessary amount of flux is stored in a hopper, and welding proceeds while supplying the flux drawn out from the hopper through a hose or a pipe to a welding portion from an opening of a nozzle to a welding portion. However, if the flux cannot be supplied due to insufficient amount of flux stored in the hopper or if the flux becomes clogged in the hose or pipe, the welded part will generate an arc in the atmosphere. As a result, the molten metal portion was exposed to the atmosphere, which sometimes resulted in poor welding.

As a method of preventing such a conventional problem, when an arc discharge occurs in the atmosphere, the arc discharge is directly detected using an optical sensor to determine whether or not the flux is supplied. Has been proposed. Further, as another method of detecting the flux exhaustion, a method of providing a vibration sensor or a weight sensor in the hopper to check the remaining amount of the flux in the hopper and detecting the remaining amount of the flux in the hopper may be considered. I have.

[0005]

However, the method using the optical sensor has a problem in that the arc heat is large and the heat resistance of the optical sensor is hindered, so that the optical sensor cannot be installed at an optimum location for reliably receiving the arc discharge. In addition, in a device using a vibration sensor or a weight sensor, there is a problem that a clog in a hose or a pipe cannot be detected.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a method in which a state in which flux is not sprayed during welding occurs. It is an object of the present invention to provide a submerged arc welding method and apparatus in which a shortage of a flux is detected from a sudden change in a feeding speed of an electrode wire to stop arc welding and no welding failure occurs.

FIG. 6 is a measurement waveform showing a change in the feeding speed of the electrode wire when the flux is cut.
As measurement conditions, output current 390A, welding voltage 31V,
The welding speed is 40 cm / min, and the molten flux is used as the type of flux. In the figure, t1 indicates that the feed speed of the electrode wire fluctuates until the welding is stabilized during the arc start period. t2 indicates the feed speed of the electrode wire when welding is progressing while spraying the flux, and the feed speed is stable. t3 indicates the feeding speed of the electrode wire when the flux is cut, and the feeding speed changes suddenly and becomes 10% or more faster than t2 where the flux is sprayed, and the fluctuation of the feeding speed is large. . The present invention relates to a method for detecting a flux breakage utilizing this phenomenon and an invention for an apparatus for realizing the method.

The present invention uses a welding power source having a drooping characteristic or a constant current characteristic to control the feeding speed of an electrode wire by controlling the feeding speed of the electrode wire according to the magnitude of the difference between the welding voltage setting signal and the welding voltage feedback signal. Detects the feed speed of the electrode wire in a submerged arc welding method that performs arc discharge between the electrode wire and the workpiece while supplying flux to the tip and melts the electrode wire and the workpiece while welding. Averaging the detected signal at regular intervals, comparing the value of the latest averaged speed signal that has been averaged with the value of the averaged speed signal that has been averaged immediately before, and calculating the difference signal between the two signals. The present invention proposes a submerged arc welding method in which when the value exceeds a predetermined value, it is determined that the flux has run out, an abnormal signal is output, and welding is interrupted by the abnormal signal.

According to a second aspect of the present invention, an electrode wire feeding speed is controlled by using a welding power source having a drooping characteristic or a constant current characteristic and controlling the feeding speed of an electrode wire according to the magnitude of a difference between a welding voltage setting signal and a welding voltage feedback signal. In a submerged arc welding method in which an arc is discharged between an electrode wire and an object to be welded while supplying a flux to the tip of the wire and the electrode wire and the object to be welded are welded, the feeding speed of the electrode wire is The average signal is averaged at regular intervals and the ratio between the value of the latest averaged speed signal that has been averaged and the value of the previous averaged averaged speed signal is a predetermined value. This invention proposes a submerged arc welding method in which it is determined that the flux has run out and an abnormal signal is output when the excess is exceeded, and welding is interrupted by the abnormal signal.

According to the third aspect of the present invention, since the sudden change in the wire feed speed when the flux is cut is accompanied by the sudden change in the welding voltage, the welding voltage setting signal is generated using a welding power source having a drooping characteristic or a constant current characteristic. The electrode wire is fed by controlling the feeding speed of the electrode wire according to the magnitude of the difference signal between the electrode wire and the welding voltage feedback signal, and supplying a flux to the tip of the electrode wire and causing an arc discharge between the electrode wire and the workpiece. In a submerged arc welding method in which welding is performed while melting a workpiece and an object to be welded, a welding voltage feedback signal is detected, and the detection signal is averaged at regular time intervals. Compares the value of the average welding voltage signal that has been averaged immediately before, and when the value of the difference signal between the two signals exceeds a predetermined value, determines that the flux has run out and is abnormal. In which it proposed a submerged arc welding method to interrupt the welding by abnormal signal outputs the No..

According to a fourth aspect of the present invention, since a sudden change in the wire feeding speed when the flux is cut is accompanied by the sudden change in the welding voltage, a welding voltage setting signal is generated using a welding power source having a drooping characteristic or a constant current characteristic. The electrode wire is fed by controlling the feeding speed of the electrode wire according to the magnitude of the difference signal between the electrode wire and the welding voltage feedback signal, and supplying a flux to the tip of the electrode wire and causing an arc discharge between the electrode wire and the workpiece. In a submerged arc welding method in which welding is performed while melting a workpiece and an object to be welded, a welding voltage feedback signal is detected, and the detection signal is averaged at regular time intervals. When the ratio of the previous averaged welding voltage signal to the value of the averaged welding voltage signal exceeds a predetermined value, it is determined that the flux has run out, an abnormal signal is output, and an abnormal signal is output. In which proposed a submerged arc welding method for inhibiting the weld by the signal.

A fifth invention proposes an apparatus for performing the submerged arc welding method of the first invention.

A sixth invention proposes an apparatus for implementing the submerged arc welding method according to the second invention.

A seventh invention proposes an apparatus for implementing the submerged arc welding method according to the third invention.

An eighth invention proposes an apparatus for performing the submerged arc welding method according to the fourth invention.

According to a ninth aspect of the present invention, there is provided a submerged arc welding apparatus according to any one of claims 5 to 8, further comprising an alarm circuit for issuing an alarm to an operator based on an output signal of the comparator.

[0017]

FIG. 1 is a connection diagram showing an example of an apparatus for performing a submerged arc welding method according to the present invention. In the figure, 1 is an object to be welded, 2 is an arc, 3 is a wire feeding roll, 4 is a wire feeding motor, 6 is an electrode wire, 7 is a welding power source, and a welding power source 7 is a commercial power source.
It is a welding power source having a drooping characteristic or a constant current characteristic that supplies welding power between the electrode wire 6 and the workpiece 1 to generate the arc 2. The electrode wire 6 is supplied from a wire feed roll 3 rotated by a wire feed motor 4. A speed detector 5 detects the feed speed of the electrode wire 6 and outputs a wire feed speed detection signal Wd. Reference numeral 8 denotes a nozzle for supplying the flux of 11 to the welding portion. Reference numeral 9 denotes a valve for adjusting the supply amount of the flux, and reference numeral 10 denotes a hopper for storing the flux 11.

Reference numeral 12 denotes a welding start switch, and 13 denotes A
This is an ND gate circuit. Reference numeral 14 denotes an electrode feed speed control circuit, a welding voltage setting circuit 15, an error amplification circuit 16, and a comparator 17.
Composed of Va is a welding voltage setting signal.
The comparator 17 compares the welding voltage setting signal Va with the welding voltage feedback signal Vb, and outputs a difference signal ΔV = Va−Vb. The error amplifier 16 outputs the output signal Δ
V is amplified to a control signal level of the wire feed motor 4 to output a wire feed control signal of Wc = A · ΔV. (However, A is a constant determined by the amplification factor of the error amplifier circuit 16) The wire feed motor 4 determines the rotation direction and the speed according to the value of the wire feed control signal Wc.

Reference numeral 18 denotes a flux cut detection signal processing circuit, which is a timer circuit 19, an averaging circuit 20, a memory circuit 21, a subtractor 22, a comparator 23, a reference value setting unit 24, a synchronization timing circuit 25, a monomultivibrator 26, It is constituted by a device control circuit 27. Also, the reference value setting device 2
Reference numeral 4 denotes a reference value which outputs a reference value Sr corresponding to the end of the flux.
And outputs a high-level signal (hereinafter represented by H) when ΔVav ≧ Sr. 2
Reference numeral 9 denotes a flip-flop circuit which is set when the output signal of the comparator 23 becomes H and is reset when the reset button 28 is pressed, and serves as a protection circuit.
Reference numeral 30 denotes an alarm which operates according to the non-inverted output signal S9 when the flip-flop circuit 29 is set, and uses a lamp, a buzzer or the like.

On the other hand, before the welding start signal (H signal) is output from the welding start switch 12, the AND gate circuit 1
The output signal S1 of No. 3 is at a low level (hereinafter denoted by L), and does not transmit any start signal S1 to the welding power source 7 or the welding voltage setting circuit 15, so that the welding power source 7 does not generate an output, and Since the error amplifier circuit 16 does not generate any output, the wire feed motor 4 is also stopped. At this time, since the wire feed speed detection signal Wd is also zero, the wire feed speed signal S2, the averaging circuit output signal Vav, and the memory circuit output signal Vm are all zero, and the output of the subtracter 22 is also zero. The switch 23 becomes L because of ΔVav <Sr, the flip-flop circuit 29 is reset, and its inverted output S8 is H. In this state, when the output signal of the welding start switch 12 becomes H, both input signals of the AND gate circuit 13 become H, so that the output signal S1 becomes H, and the H signal is transmitted to the welding power source 7 and the welding voltage setting circuit 15. You. The H signal causes the welding voltage setting circuit 15 to output a welding voltage setting signal Va, and the comparator 17 outputs a difference signal ΔV = Va−V between the signal Va and the welding voltage feedback Vb.
b is calculated and supplied to the error amplifying circuit 16, the error amplifying circuit 16 rotates the wire feed motor 4 in response thereto, and the welding power source 7 generates an output according to the H signal from the AND gate circuit 13. .

FIG. 2 is a diagram showing the time course of each signal in the connection diagram shown in FIG. In FIG. 2, (A)
Represents the output signal S1 of the AND gate circuit 13, and (B)
Indicates an output signal Wd of the speed detector 5. (C) shows the wire feed speed signal S2 that has passed through the timer circuit 19,
(D) shows the timed output signal S3 of the timer circuit 19.
(E) shows the output signal S4 of the synchronous timing circuit 25, and (F) shows the output signal S4 of the monomultivibrator 26.
5, (G) shows the output signal Vav of the averaging circuit 20, (H) shows the output signal Vm of the memory circuit 21,
(I) shows the output signal S6 of the subtractor control circuit 27.
(J) is an output signal ΔVav = Vav− of the subtractor 22 obtained by subtracting the memory circuit output signal Vm from the averaging circuit output signal Vav.
(K) indicates the output signal S7 of the comparator 23,
(L) indicates the output signal S8 of the flip-flop circuit 29.

In FIG. 1 and FIG. 2, when the welding start switch 12 is pressed, the output of the AND gate circuit 13 becomes as shown in FIG.
The activation signal S1 shown in FIG. The welding power source 7 receives the start signal S1 and starts supplying welding power between the electrode wire 6 and the workpiece 1. The start signal S1 is input to the electrode feed speed control circuit 14, and when the start signal S1 becomes H, the wire feed control signal Wc is output, and the wire feed motor 4 starts rotating. Wire feed motor 4
Rotates, the speed detector 5 detects the feed speed of the electrode wire 6 and outputs a wire feed speed detection signal Wd shown in FIG.

The start signal S1 is also input to the timer circuit 19. The timer circuit 19 starts counting at the same time as the start signal S1 becomes H, and counts the time until the welding is stabilized (for example, 5 seconds). 2 (D) is output. Further, the wire feed speed detection signal Wd is also input to the timer circuit 19, and the timer circuit 19 finishes outputting the timed output signal S3 and, at the same time, outputs the subsequent wire feed speed detection signal Wd to FIG. It is output as a wire feed speed signal S2 shown. The timed output signal S3 is input to the synchronization timing circuit 25, and at the same time when the output signal of the timed output signal S3 ends, the synchronization timing circuit 25 outputs the H output signal for a predetermined period of time T1 at a constant period in FIG. As shown in FIG. The averaging circuit 20 receives the two signals of the wire feeding speed signal S2 and the output signal S4 of the synchronous timing circuit 25, and outputs the signal S4
Is input, the averaging circuit 20 immediately starts averaging the wire feed speed signal S2. The averaging circuit 20
When the next output signal S4 of the synchronous timing circuit 25 is input, the output signal Vav is reset by the rise of the input signal, and after the reset, averaging of the wire feed speed signal S2 is started again. FIG. 2 (G) shows an averaging circuit 2
The output state of the output signal Vav of 0 is shown.

On the other hand, the output signal S4 of the synchronization timing circuit 25 is also supplied to the mono-multivibrator 26, and the predetermined time T2 is determined by the fall of the input signal S4.
Is output as shown in FIG. 2 (F). When the output signal S5 of the monomultivibrator 26 is input, the memory circuit 21 stores the value of the output signal Vav of the averaging circuit 20 at the time of the falling of the input signal S5 as shown in FIG.

The output signal S of the mono-multi vibrator 26
5 is also supplied to the subtractor control circuit 27, and the input signal S
At the rise of 5, the subtractor control circuit 27 starts operating and outputs a signal S6 for a predetermined time T3. However, the subtractor control circuit 27 inhibits the operation for the first input of the input signal S5 as shown in FIG.
The circuit is configured to start the operation from the input and output the output signal S6. The output signal Vav of the averaging circuit 20, the output signal Vm of the memory circuit 21, and the output signal S6 of the subtractor control circuit 27 are input to the subtractor 22. The subtractor 22 operates only during the period T3 during which the output signal S6 of the subtractor control circuit 27 is being input, and the averaging circuit 20 operates.
Is subtracted from the output signal Vav of the memory circuit 21 to obtain a difference signal ΔVav = Vav−Vm, which is output to the comparator 23. Here, since the value of the output signal Vm of the memory circuit becomes the same value as the value of the immediately preceding averaging circuit Vav, the subtracter 22
The output signal ΔVav is as shown in FIG.

The output signal ΔVav of the subtractor 22 is supplied to the comparator 23.
Is input, the comparator 23 compares the reference value Sr set by the reference value setting unit 24 with the output signal ΔVav of the subtractor 22, and when ΔVav ≧ Sr as shown in FIG. An H signal is output, and when ΔVav <Sr, an L signal is output. As described above, when the arc is generated in the atmosphere due to insufficient flux, the arc voltage rises sharply and the wire feed speed rises sharply as shown in FIG. When the output signal S7 of the detector 23 becomes H, it is determined that the flux has run out.

On the other hand, when the signal S7 becomes H signal, the flip-flop circuit 29 is set, the inverted output S8 of the flip-flop circuit 29 becomes L, and as a result, the output signal S1 of the AND gate circuit 13 becomes L, and The rotation of the feed motor 4 and the output of the welding power source 7 are stopped, or the output is stopped by performing a predetermined welding end treatment, an anti-stick treatment, or the like.

FIG. 3 is a connection diagram showing another example of an apparatus for performing the submerged arc welding method of the present invention. In the embodiment shown in the figure, the value of the output signal Vav of the averaging circuit 20 is divided by the value of the output signal Vm of the memory circuit 21, and the ratio S11 = Vav
/ Vm is determined, and when the determined value of the ratio S11 exceeds the reference value Sr of the reference value setting device 24, it is determined that the flux is out, and the arc welding is stopped. In the figure, for this purpose, a dividing circuit 32 is connected and inserted between the output of the memory circuit 21 and the input of the comparator 23 as shown in the figure. In the figure, the other components have the same functions as those of the embodiment shown in FIG. 1, and the detailed description thereof will be omitted.

In the embodiment of FIG. 3, before the arc welding is started, the output signal S1 of the AND gate circuit 13 is at L level.
Since no start signal is transmitted to the welding power source 7 or the welding voltage setting circuit 15, the welding power source 7 does not generate an output, and the error amplification circuit 16 does not generate any output. Has also stopped. At this time, since the wire feed speed detection signal Wd is also zero, the wire feed speed signal S2, the averaging circuit output signal Vav, and the memory circuit output signal Vm are all zero, and the output signal S1 of the division circuit 32
The value of 1 is naturally zero, and the comparator 23 has S11 <Sr, so that the output signal S7 of the comparator 23 becomes L. Signal S7 is L
, The flip-flop circuit 29 has been reset, and its inverted output S8 is at H.

When the start signal S1 becomes H in the same manner as described with reference to the apparatus of FIG. 1, the welding power source 7 starts supplying welding power between the electrode wire 6 and the workpiece 1. Further, a wire feed control signal Wc is output, and the wire feed motor 4 is output.
Starts spinning. When the wire feed motor 4 rotates, the speed detector 5 detects the feed speed of the electrode wire 6 and outputs a wire feed speed detection signal Wd.

The output signal Wd of the speed detector 5 is supplied to a flux-out detection signal processing circuit 31 and is output from a division circuit 32.
Represents the value of the output signal Vav of the averaging circuit 20 in the memory circuit 21
Is divided by the value of the output signal Vm, and the value of the ratio obtained by the division circuit 32 is S11 = Vav / Vm, which is output to the comparator 23. When the output signal S11 of the division circuit 32 is input to the comparator 23, the comparator 23 compares the reference value Sr set by the reference value setting unit 24 with the output signal S11 of the division circuit 32, and determines that S11 ≧ Sr Outputs the H signal when it becomes true.

On the other hand, when the signal S7 becomes H signal, the flip-flop circuit 29 is set, the inverted output S8 becomes L, and the output signal S1 of the AND gate circuit 13 changes from H to L.
The rotation of the wire feed motor 4 or the welding power source 7
Stop output of

At the same time, the non-inverted output S9 of the flip-flop circuit 29 becomes H, and activates the alarm 30 to notify the operator of the abnormality. In addition, the flip-flop circuit 2
9 keeps the set state until the operator presses the reset switch 28, so that the wire feed motor 4 or the welding power source 7 keeps the output stopped.

FIG. 4 is a connection diagram showing another example of an apparatus for performing the submerged arc welding method of the present invention. In the apparatus shown in FIG. 6, the reason why the wire feed speed is increased when the flux is cut in FIG. 6 is that the arc generated in the flux is generated in the atmosphere because the welding voltage ( Arc voltage) rises sharply, and the electrode feed speed control circuit reacts to return this to the set value. It is estimated that the feed speed has changed suddenly. Thus, it is determined that the flux has run out. In the embodiment shown in the figure, the welding voltage feedback signal Vb is supplied to a flux cutoff detection signal processing circuit 18, and when the welding voltage signal S2 is input to the averaging circuit 20, the averaging circuit 20 starts averaging processing. An average welding voltage signal Vav is output.

On the other hand, the subtractor 22 subtracts the output signal Vm of the memory circuit 21 from the output signal Vav of the averaging circuit 20 to obtain a difference signal ΔVav = Vav−Vm, and outputs it to the comparator 23. When the output signal ΔVav of the subtractor 22 is input to the comparator 23, the comparator 23 compares the reference value Sr set by the reference value setting unit 24 with the output signal ΔVav of the subtractor 22 and calculates ΔVav.
When av ≧ Sr, it is determined that the flux has run out and the arc welding is stopped. The other operations are the same as those of the apparatus shown in FIG. 1, and the other components in FIG. 4 have the same functions as those in the embodiment shown in FIG.

FIG. 5 is a connection diagram showing another example of an apparatus for performing the submerged arc welding method of the present invention. In the embodiment shown in the figure, the welding voltage feedback signal Vb is supplied to a flux cutout detection signal processing circuit 31, and when the welding voltage signal S2 is input to the averaging circuit 20, the averaging circuit 2
0 starts the averaging process and outputs an average welding voltage signal Vav.

On the other hand, the dividing circuit 32 divides the value of the output signal Vav of the averaging circuit 20 by the value of the output signal Vm of the memory circuit 21, and the value of the ratio obtained by the dividing circuit 32 is S11 =
Vav−Vm is output to the comparator 23. When the output signal S11 of the division circuit 32 is input to the comparator 23, the comparator 23 compares the reference value Sr set by the reference value setting unit 24 with the output signal S11 of the division circuit 32, and S11 ≧ Sr
When it is determined that the flux has run out, the arc welding is stopped. Other operations are shown in FIG.
The other components in FIG. 5 have the same functions as those in the embodiment shown in FIG.

The relationship between H and L of each signal described in each of the above embodiments and the logic circuit to be used are not limited to those shown in each of the embodiments, and the same operations as those described in each of the embodiments. And the logical configuration is arbitrary.

[0039]

The submerged arc welding method and apparatus according to the present invention detects the wire feeding speed or the welding voltage and detects the wire feeding speed or the welding voltage when the flux is normally supplied to the welding portion. The value is compared with the value of the wire feed speed or the value of the welding voltage when the flux in the hopper is no longer supplied to the welded part, and when the difference or ratio between the compared values is larger than a predetermined value, the flux Since it is determined that the arc discharge has occurred, an optical sensor is not required for a conventionally used device for directly detecting an arc discharge with an optical sensor. In addition, the present invention provides a weight sensor provided in the hopper to check the amount of flux consumed in the hopper and to detect clogging in the hose or pipe, which has been a problem in the device for detecting the lack of flux. Has a great effect that can be eliminated.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing an example of an apparatus for performing a submerged arc welding method of the present invention.

FIG. 2 is a timing chart for explaining the operation of FIG.

FIG. 3 is a connection diagram showing another example of an apparatus for performing the submerged arc welding method of the present invention.

FIG. 4 is a connection diagram showing another example of an apparatus for performing the submerged arc welding method of the present invention.

FIG. 5 is a connection diagram showing another example of an apparatus for performing the submerged arc welding method of the present invention.

FIG. 6 is a waveform showing a change in the feeding speed of the electrode wire when the molten flux is cut.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Workpiece 2 Arc discharge 3 Wire feed roll 4 Wire feed motor 5 Speed detector 6 Electrode wire 7 Welding power supply 8 Nozzle 9 Valve 10 Hopper 11 Flux 12 Weld start switch 13 AND gate circuit 14 Electrode feed speed control circuit REFERENCE SIGNS LIST 15 welding voltage setting circuit 16 error amplification circuit 17 comparator 18 flux out detection signal processing circuit 19 timer circuit 20 averaging circuit 21 memory circuit 22 subtractor 23 comparator 24 reference value setting device 25 synchronization timing circuit 26 mono multivibrator 27 subtraction Control circuit 28 Reset switch 29 Flip-flop circuit 30 Alarm 31 Flux out detection signal processing circuit 32 Divider circuit 33 Flux out detection signal processing circuit 34 Timer circuit 35 Sampling circuit 36 Arithmetic processing circuit 37 Synchronous tie Wiring voltage setting signal Vb Welding voltage feedback signal Wc Wire feed control signal Wd Wire feed speed detection signal Vm Memory circuit output signal Vav Averaging circuit output signal

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinnori Kai 1-3-8 Yaesu, Chuo-ku, Tokyo Inside Nittetsu Hard Co., Ltd. (72) Inventor Akira Nitta 2-1-1-11 Tagawa, Yodogawa-ku, Osaka-shi Daihen Co., Ltd. (72) Inventor Hiroyuki Ibuki 2-1-1, Tagawa, Yodogawa-ku, Osaka F-term in Daichen Co., Ltd. (Reference) 4E001 AA03 BB05 DB04 DC05 DC09 EA01 EA10 4E082 AA06 BB01 EC01 EC11 EE03 EE07 EF21 EF26

Claims (9)

[Claims] An electrode wire feed speed is controlled by using a welding power source having a drooping characteristic or a constant current characteristic to control a feeding speed of an electrode wire according to a magnitude of a difference signal between a welding voltage setting signal and a welding voltage feedback signal. In a submerged arc welding method in which an arc is discharged between the electrode wire and the work to be welded while supplying a flux to the portion and the electrode wire and the work to be welded are welded, the feeding of the electrode wire is performed. The speed is detected, the detected signal is averaged at regular intervals, and the value of the latest averaged speed signal that has been averaged is compared with the value of the previous averaged averaged speed signal. A submerged arc welding method in which when the value of the signal exceeds a predetermined value, it is determined that the flux has run out, an abnormal signal is output, and welding is interrupted by the abnormal signal. 2. The electrode wire feeding speed is controlled by using a welding power source having a drooping characteristic or a constant current characteristic and controlling the feeding speed of the electrode wire according to the magnitude of the difference signal between the welding voltage setting signal and the welding voltage feedback signal. In a submerged arc welding method in which an arc is discharged between the electrode wire and the work to be welded while supplying a flux to the portion and the electrode wire and the work to be welded are welded, the feeding of the electrode wire is performed. The speed is detected, the detection signal is averaged at regular intervals, and the ratio between the value of the latest averaged speed signal that has been averaged and the value of the previous averaged averaged speed signal is a predetermined value. A submerged arc welding method for judging that the flux has run out, outputting an abnormal signal and interrupting the welding based on the abnormal signal. 3. An electrode wire feeding speed is controlled by using a welding power source having a drooping characteristic or a constant current characteristic and controlling a feeding speed of an electrode wire according to a magnitude of a difference signal between a welding voltage setting signal and a welding voltage feedback signal. In a submerged arc welding method in which an arc is discharged between the electrode wire and the work to be welded while supplying a flux to the portion to perform welding while melting the electrode wire and the work to be welded, the welding voltage feedback signal is supplied. The detected signal is averaged at regular intervals, and the value of the averaged welding voltage signal that has been averaged and the value of the averaged welding voltage signal that has been averaged immediately before are compared. When the value of the difference signal exceeds a predetermined value, it is determined that the flux has run out, an abnormal signal is output, and welding is interrupted by the abnormal signal. Contact method. 4. An electrode wire feeding speed is controlled by using a welding power source having a drooping characteristic or a constant current characteristic and controlling a feeding speed of an electrode wire according to a magnitude of a difference signal between a welding voltage setting signal and a welding voltage feedback signal. In a submerged arc welding method in which an arc is discharged between the electrode wire and the work to be welded while supplying a flux to the portion to perform welding while melting the electrode wire and the work to be welded, the welding voltage feedback signal is supplied. The detected signal is averaged at regular intervals, and the ratio between the value of the averaged latest welding voltage signal subjected to the averaging process and the value of the immediately preceding averaged welding voltage signal is predetermined. A submerged arc welding method for judging that the flux has run out and outputting an abnormal signal when the value is exceeded, and prohibiting welding based on the abnormal signal. 5. An electrode wire feeding speed is controlled by using a welding power source having a drooping characteristic or a constant current characteristic and controlling a feeding speed of an electrode wire according to a magnitude of a difference signal between a welding voltage setting signal and a welding voltage feedback signal. In a submerged arc welding apparatus for performing welding while melting the electrode wire and the workpiece by performing arc discharge between the electrode wire and the workpiece while supplying a flux to the portion, the feeding of the electrode wire is performed. A speed detector for detecting a speed, an averaging circuit for averaging a speed detection signal of the speed detector at regular intervals, and a memory for storing a value Vm immediately before the averaged average speed signal Difference between the value of the latest average speed signal Vav averaged by the circuit and the averaging circuit and the value Vm of the immediately preceding average speed signal stored in the memory circuit ΔVav = Vav−Vm ΔV is compared with the set value Sr of the output ΔVav and the reference value setter of the subtractor and subtractor for calculating
A submerged arc welding apparatus comprising: a comparator that outputs an abnormal signal by determining that the flux has run out when av ≧ Sr; and a protection circuit that interrupts welding by an output signal of the comparator. 6. An electrode wire feeding speed is controlled by using a welding power supply having a drooping characteristic or a constant current characteristic to control a feeding speed of an electrode wire according to a magnitude of a difference signal between a welding voltage setting signal and a welding voltage feedback signal. In a submerged arc welding apparatus for performing welding while melting the electrode wire and the workpiece by performing arc discharge between the electrode wire and the workpiece while supplying a flux to the portion, the feeding of the electrode wire is performed. A speed detector for detecting a speed, an averaging circuit for averaging a speed detection signal of the speed detector at regular intervals, and a memory for storing a value Vm immediately before the averaged average speed signal Ratio S11 = Vav / V between the value of the latest average speed signal Vav averaged by the circuit and the averaging circuit and the value Vm of the immediately preceding average speed signal stored in the memory circuit The value of the ratio obtained by the dividing circuit and divider circuit for calculating S11 and the reference value setter setting S
A submerged arc welding apparatus comprising: a comparator that compares r with S11 ≧ Sr to determine that the flux has run out and outputs an abnormal signal; and a protection circuit that interrupts welding by an output signal of the comparator. 7. An electrode wire feeding speed is controlled by using a welding power source having a drooping characteristic or a constant current characteristic and controlling a feeding speed of an electrode wire according to a magnitude of a difference signal between a welding voltage setting signal and a welding voltage feedback signal. In a submerged arc welding apparatus that performs arc discharge between the electrode wire and the work to be welded while supplying a flux to the portion and melts the electrode wire and the work to be welded, the welding voltage feedback signal is provided. An averaging circuit for detecting and averaging the detection signal at regular time intervals, a memory circuit for storing a value Vm immediately before the averaged average welding voltage signal, and an averaging process for the averaging circuit Difference ΔVav = the value of the latest average welding voltage signal Vav thus obtained and the value Vm of the immediately preceding average welding voltage signal stored by the memory circuit.
A subtractor for calculating Vav−Vm and an output ΔVav of the subtractor
And a comparator that compares the set value Sr of the reference value setter and determines that the flux has run out when ΔVav ≧ Sr and outputs an abnormal signal, and a protection circuit that interrupts welding based on the output signal of the comparator. Submerged arc welding equipment provided. 8. An electrode wire feeding speed is controlled by using a welding power source having a drooping characteristic or a constant current characteristic and controlling a feeding speed of an electrode wire according to a magnitude of a difference signal between a welding voltage setting signal and a welding voltage feedback signal. In a submerged arc welding apparatus that performs arc discharge between the electrode wire and the work to be welded while supplying a flux to the portion and melts the electrode wire and the work to be welded, the welding voltage feedback signal is provided. An averaging circuit for detecting and averaging the detection signal at regular time intervals, a memory circuit for storing a value Vm immediately before the averaged average welding voltage signal, and an averaging process for the averaging circuit Ratio S11 = the value of the latest average welding voltage signal Vav thus obtained and the value Vm of the immediately preceding average welding voltage signal stored by the memory circuit.
A dividing circuit for calculating Vav / Vm and a ratio value S11 obtained by the dividing circuit are compared with a set value Sr of a reference value setting device. When S11 ≧ Sr, it is determined that the flux is out and an abnormal signal is output. And a protection circuit for interrupting welding by an output signal of the comparator. 9. An alarm circuit for issuing an alarm to an operator based on an output signal of the comparator.
The submerged arc welding apparatus according to any one of the above.