JPS6134906B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for measuring welding heat input when a welding holder or welding torch is moved manually or semi-automatically.

[Prior Art] It has been known that the amount of welding heat input to a welded part is an important factor that influences the welding result.
Generally, the arc voltage is E1 (volt) and the welding current is I.
1(A), welding speed is V1 (cm/sec), electrical input to the workpiece is P1 (kw), heat input per unit length is Q
(kilo-joule/cm), and if the constant is K1, then Q=K1(P1/V1) =K1(E1 I1)/V1...(1) holds true. This equation (1) can be expressed even more simply in some cases.

For example, when manual welding is performed using a welding power source with constant current characteristics, the welding current I1 (A) has a substantially constant value, so if it is a constant K2, then Q = K2 (E1 / V1) ... (2) holds true.

Also, when performing semi-automatic welding using a welding power source with constant voltage characteristics, the arc voltage E1 (volt) is approximately constant, so if the constant is K3, Q = K3 (I1 / V1) ... ( 3) holds true.

In the conventional automatic arc welding method, the signal V corresponding to the welding speed V1 can be easily obtained by detecting the traveling speed of the automatic traveling trolley, so heat input measurement in the automatic welding machine and control based on the measured value have already been performed. Proposed.

[Problems with conventional technology] However, in manual welding and semi-automatic welding, there is no automatic traveling cart and the welding torch is artificially moved along the welding line, so the welding speed V1 cannot be detected. Therefore, in the past, it has been extremely difficult to obtain a device that can simply, quickly and accurately measure heat input in manual or semi-automatic welding.

In view of the above, an object of the present invention is to provide a welding heat input measuring method for determining the average welding heat input over a distance traveled by the arc during an arbitrary period in arc welding such as manual welding and semi-automatic welding.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a method for welding a workpiece 1, as shown in FIGS. In a heat input measurement method for arc welding in which welding is performed while moving an arc 3 generated from a welding electrode 2 along a welding line 1a, an arc is moved from a welding start position A to a position B at a predetermined distance L approximately along the welding line. An arc photodetector 7 that outputs an arc signal when detecting the The average welding heat input from the welding start position A to the position B where the arc light detector 7 is placed is calculated by integrating the signal P/L obtained by dividing the signal P corresponding to the electric power by a predetermined distance L. It is characterized by measuring.

[Operation of the invention] The present invention is capable of measuring the distance L traveled by an arc during a given period in manual welding or semi-automatic welding.
If the time required to weld [cm] is T [sec], then the average welding heat input Q within that distance is
If [kilo-joule/cm] is a constant K4, ∫ ^T _p Vdt
= L, so It can be expressed as. The present invention measures welding heat input based on equation (4) above.

[Example] The welding heat input measuring method of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an apparatus for carrying out the welding heat input measurement method of the present invention, in which 1 is a workpiece, 1a is a welding line, and 2 is an arc 3 that is generated along the welding line 1a. Welding electrode that moves while moving, 4
5 is a welding power source, and 5 is a welding device supplied between a workpiece 1 and a welding electrode 2 by inputting a current signal I corresponding to a welding current obtained from a current transformer 5a and a voltage signal E corresponding to an arc voltage. Signal P corresponding to power
This is a power calculator that outputs . Reference numeral 7 denotes an arc photodetector placed at a position B apart from the welding start position A along the welding line by a predetermined distance L, and detects an arc signal when the arc light passes through this detector. Output. As this arc photodetector 7, a light receiving element such as a phototransistor or a photoelectric cell is used. 10 is a welding length setting device for setting the welding length corresponding to a predetermined distance L, and the output side of this setting device receives a signal P obtained by dividing a signal P corresponding to the instantaneous power supplied by the distance L. /L is output. 6 is an integrating circuit that integrates the output signal P/L of the welding length setting device 10, and 8 is a reset circuit that resets the integral operation of the integrating circuit 6. This reset circuit is composed of, for example, a push button switch PBa. A reset signal is output by pressing . Reference numeral 9 denotes a display for displaying the value of the output signal of the integrating circuit 6. As this display, for example, a meter using the principle of a voltmeter is used. 11 is a control power supply; CRC is a relay exciting coil having a normally open contact CRa and a normally closed contact CRb; when the arc photodetector 7 receives arc light and becomes conductive, the coil CRc is excited; , contact CRa and
CRb works. PBb is a push button switch PBa
This is a pushbutton switch with a normally closed contact that works with the switch.

To start welding in the above-mentioned apparatus, first, the signal in the integrating circuit 6 is reset by the reset circuit 8 (for example, the push button switch PBa). Also, the predetermined distance L is set by the welding length setting device 10.
Set to . Start welding and move arc 3 to weld line 1
When the power calculator 5 is moved along the line a, the power calculator 5 outputs a signal P corresponding to the power supplied between the workpiece 1 and the welding electrode 2. Therefore, the welding length setting device 10 receives the signal P and outputs the signal P/L,
The integration circuit 6 receives the output signal P/L of the welding length setting device 10 and starts integration. When the arc 3 moves a predetermined distance L and passes the position B of the welding line 1a where the arc photodetector 7 is placed, the arc photodetector 7 becomes conductive and the relay coil CRc is excited. be done. Therefore, the normally closed contact CRb becomes an open circuit, and the supply of the input signal to the integrating circuit 6 is stopped, so the integrating circuit 6 holds the signal corresponding to the final integral value ∫P/Ldt,
The display 9 displays a display corresponding to the signal, that is, indicates the average welding heat input over the distance L. Also, at this time, the normally open contact CRa of the relay becomes closed, thereby self-holding the relay. Welding is stopped at an arbitrary time after the arc passes the position of the arc detector 7,
When the interlocking pushbutton switches PBa and PBb are pressed, the integral signal of the integral circuit 6 is reset, while the relay coil CRc is de-energized and the contact is closed.
CRa and CRb return to their original states.

FIG. 2 shows another embodiment of the apparatus for implementing the welding heat input measuring method of the present invention. What differs from FIG. A conversion circuit 12 receives the output signal P/L of the device 10 and generates a pulse signal of a frequency corresponding to the signal P/L, a counter 13 for counting the number of pulse signals, and a digital display 9' are provided. This is the point.

With the configuration shown in FIG. 2, the output signal P/L of the welding length setting device 10 is converted into a pulse signal, the number of pulse signals is counted, and the digital display 9'
represents the average welding heat input at distance L. In this case, the reset circuit 8 resets the count value of the counter 13. Other operations are the same as in FIG. 1. In FIG. 2, the same operation as in FIG. 1 can be obtained by using an integrating circuit for integrating pulse signals in place of the counter 13 and using the principle of a voltmeter for the display.

In Figures 1 and 2, welding length setting device 1
0 can be inserted at any position from the input side of the power calculator 5 to the input side of the integrating circuit 6 or counter 12. In the present invention, the capacity of the integrating circuit or counter is 1/1/2 of a predetermined distance L.
There is an advantage that it can be done with

Furthermore, if the predetermined distance L needs to be kept at a constant value, there is no particular need to provide a welding length setting device, and the welding length setting device can be omitted by selecting other circuit constants.

In each of the embodiments shown in FIGS. 1 and 2 above,
A current signal I corresponding to the welding current value obtained from the current transformer 5a and a voltage signal E corresponding to the arc voltage value are input to the power calculator 5, and a signal P corresponding to the product of these is obtained. The configuration of the power calculator 5 can be modified as appropriate. For example, when performing manual welding using a welding power source with constant current characteristics,
Since the current signal I corresponding to the welding current value is substantially constant, the voltage signal E corresponding to the arc voltage becomes the signal P corresponding to the instantaneous power value. Further, if a welding current setting device is present in the welding power source 4, a signal corresponding to the output signal of this setting device may be used as the current signal I corresponding to the welding current. Conversely, when performing semi-automatic welding using a welding power source with constant voltage characteristics, the voltage signal E corresponding to the arc voltage value is approximately constant, so the welding power signal P corresponding to the instantaneous power value is A current signal I corresponds to the current corresponding to the current.

Further, if the welding power source 4 includes an arc voltage setting device, a signal corresponding to the output signal of this setting device may be used as the voltage signal E corresponding to the arc voltage.

Furthermore, the current signal I corresponding to the welding current can be obtained by detecting leakage magnetic flux in the vicinity of the welding current-carrying circuit with a coil and using its output signal, or by detecting the Joule heat generated in the welding circuit with a thermocouple. The output signal can be used. If the voltage signal E corresponding to the arc voltage is not constant, the instantaneous power value can be determined by combining these signals with the signal corresponding to the arc voltage or the signal corresponding to the output signal of the arc voltage setting device. A signal P can be obtained.

As the display 9 shown in FIG. 1, in addition to a meter using the principle of a voltmeter, a digital display having an A/D converter, a printer, or the like can be used.

It goes without saying that the present invention can be applied to heat input measurement in automatic welding as well as manual or semi-automatic welding.

[Effects of the Invention] As described above, according to the present invention, it is possible to quickly and easily measure welding heat input in manual or semi-automatic welding, etc., which has conventionally been difficult to measure. In particular, according to the present invention, the signal P/L obtained by dividing the signal P corresponding to the welding power supplied between the workpiece and the welding electrode by a predetermined distance L is used as the signal to be integrated. When measuring the average welding heat input from the starting position to the position where arc light is detected, it is possible to reduce the capacity of an integrating circuit or a counter used for integration. Further, according to the present invention, when an integrating circuit is used for integration, the capacity of the integrating circuit can be made small.
This has the advantage that a portion of the integrating circuit with good linearity can be used for the integrating operation, and measurement errors can be minimized. Further, in the present invention, since the integration operation is performed only until the arc photodetector detects an arc and outputs an arc signal, there is an advantage that accurate measurements can be made.

[Brief explanation of the drawing]

FIGS. 1 and 2 are configuration diagrams showing examples of different measuring devices for implementing the welding heat input measuring method of the present invention, respectively. 1... Workpiece to be welded, 1a... Welding line, 2... Welding electrode, 3... Arc, 4... Welding power source, 5... Power calculator, 6... Integrating circuit, 7... Arc photodetector , 8...Reset circuit, 9...Display device, 10...
...Welding length setting device, H...Welding start position, B...Position where the arc light detector is placed.

Claims (1)

[Scope of Claims] 1. A heat input measurement method for arc welding in which an arc generated from a welding electrode is moved along the welding line of a workpiece, in which An arc photodetector that outputs an arc signal when an arc is detected at a distance L is disposed, and the object to be welded and the welding electrode The arc photodetector is placed from the welding start position by integrating the signal P/L obtained by dividing the signal P corresponding to the electric power supplied between the welding start position and the predetermined distance L. A welding heat input measuring method characterized by measuring the average welding heat input up to a position. 2. The welding heat input measuring method according to claim 1, wherein the integrated value of the signal P/L is an integrated value ∫P/Ldt of the input signal. 3. The welding heat input measuring method according to claim 1, wherein the integrated value of the signal P/L is a count value of a pulse signal having a frequency corresponding to the input signal. 4. The welding heat input measuring method according to claim 1, wherein the integrated value of the signal P/L is an integrated value of a pulse signal of a frequency corresponding to the input signal.