JP2002086270A - Consumable electrode type arc welding method and welding device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] When a welding speed is approximately 2 m / min or more and a welding wire is fed by a feeding motor and an arc is generated between the welding wire and a base material, a molten metal is formed. Provided is a welding method and apparatus in which arc start is stabilized without occurrence of scattering and arc breakage, and does not cause insufficient welding at a welding start portion. SOLUTION: At the start of welding, a wire feed speed is fed at a speed lower than a steady state. At the start of welding, after the wire and the base material are short-circuited, the feed speed of the welding wire is accelerated, and a preset wire feed speed is set. , A consumable electrode type arc welding method in which the wire feed speed is reduced to a wire feed speed lower than a preset wire feed speed in steady welding, and further accelerated to the wire feed speed in steady welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a welding speed of about 2 m.
The present invention relates to a consumable electrode type arc welding method and apparatus at a rate of at least / min.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing the configuration of a conventional general consumable electrode type arc welding apparatus.
1 is a welding power source, 2 is a wire feeding circuit, 3 is a sequence control circuit, and when welding starts or stops, a command to start or stop output to the welding power source 1 and the wire feeding circuit 2 and a value of each output value. Perform a switch. 4
Is a wire feed motor driven by the output of the wire feed circuit 2, 5 is a pair of rollers driven in conjunction with the wire feed motor, 6 is a consumable electrode (hereinafter referred to as a wire), and 7 is a positive electrode from the welding power source 1. Welding torch whose output is powered,
Reference numeral 8 denotes a base material connected to the negative output of the welding power source 1.

In the arc welding apparatus having the above configuration, when the sequence control circuit 3 receives a welding start command from a control device (not shown), the sequence control circuit 3
A welding start command is output to the wire feeding circuit 2 and the welding power source 1, and the wire feeding motor 4 starts rotating according to the output of the wire feeding circuit 2, and at the same time, the output of the welding power source 1 through the welding torch 7 through the welding torch 7. A voltage is applied between 6 and base material 8. When the wire 6 sandwiched between the pair of rollers 5 rotated by the drive of the wire feed motor 4 is fed and reaches the base material 8, an output current from the welding power source 1 flows between the wire 6 and the base material 8. The tip of the wire 6 is melted and an arc is generated between the wire 6 and the base material 8 to perform welding. In this case, in order to smoothly perform the process from the short circuit between the wire 6 and the base material 8 to the generation of the arc, it is necessary to sufficiently heat and melt the tip of the wire 6 to generate a stable arc. From this, the wire feed speed until the wire 6 is short-circuited to the base material 8 is set to be lower than the wire feed speed after the arc is generated, and the tip of the wire 6 is sufficiently increased by gradually accelerating. It is said that it can be heated and melted, and that the arc can be stabilized at the start of the arc. 4A and 4B are diagrams showing timings of the above operation, wherein FIG. 4A shows a wire feed speed set value, and FIG. 4B shows a welding power source output. That is, at the welding start time (t0), the feeding of the wire and the application by the welding power source are started simultaneously, and the feeding is performed at a low feeding speed (S0) until the wire and the base material are short-circuited (t1). It operates according to a command of the sequence control circuit so that the speed is increased after time (t1) to become a constant speed (S1).

[0004] Japanese Patent Application Laid-Open Nos. 55-126382 and 10-34335 also propose the following stabilization of an arc at the start of welding at the start of welding. FIG. 5 is a diagram showing the timing of the wire feed speed at the start of welding in JP-A-55-126382. Until welding is started and the wire is short-circuited to the base material (from t0 to t1), the wire is fed at a constant speed higher than the wire feeding speed of the steady welding, thereby shortening the time and improving work efficiency. Is being planned. Also, an arc is generated after the wire and the base material are short-circuited (from t1 to t2).
Up to this point, a constant feed rate lower than the wire feed rate for steady welding has been proposed to make the arc generation smoother and arc stability at the start of the arc. FIG.
It is a diagram showing timing of motor rotation speed (wire feed speed) at the start of welding in Japanese Patent No. 35. Until welding is started and the wire short-circuits with the base material (from t0 to t1),
The wire is fed at a constant speed lower than the wire feeding speed of the steady welding, and the wire is fed at a constant speed higher than the wire feeding speed of the steady welding for a certain time after the short circuit (that is, the welding current is higher). Thus, it is proposed that even if a failure occurs at the start of the arc, it does not take long time to restart the arc, and that the arc is stabilized at the start of the arc even when welding at a low current.

[0005]

Problems to be Solved by the Invention
In Japanese Patent Publication No. 82, the wire is fed at a speed higher than that of the steady welding until the wire is short-circuited with the base material. However, the wire feeding speed to be applied is approximately 15 m / min for welding at approximately 2 m / min or more. If the wire is fed at a higher wire feeding speed, the wire and the base material collide violently, and buckling of the wire may occur. In addition, the wire feeding speed is high before the wire is short-circuited with the base material, and the wire starts melting after the wire feeding speed becomes low, so that the amount of welding at the start of welding is small. At the start of welding, an insufficient amount of welding occurs. In Japanese Patent Application Laid-Open No. H10-34335, the wire is fed for a certain period of time after the wire is short-circuited with the base material, at a speed higher than the speed in the steady welding. Arc does not stabilize due to insufficient melting.

Further, in a method of setting the wire feeding speed until the wire is short-circuited to the base material to be lower than the wire feeding speed of the steady welding, and gradually accelerating, the arc start is stabilized. However, the amount of welding is reduced as compared with the case where welding is performed at the wire feed speed in the steady welding from the beginning, and the amount of welding at the welding start portion becomes insufficient. Also,
If an arc is generated after the wire feeding speed is accelerated at a slope at which an arc can be generated and the wire feeding speed in steady welding (approximately 15 m / min) is reached, it takes a long time and the work efficiency is significantly reduced. If an arc is generated during acceleration, a shortage of welding occurs in a steady-state weld zone in addition to at the start of welding. Therefore, the problem to be solved by the present invention is approximately 2
An object of the present invention is to provide a welding method and apparatus in which welding is performed at a rate of at least m / min, in which the start of the molten metal and the breakage of the arc do not occur, the arc start is stable, and the welding amount at the welding start portion is not insufficient. .

[0007]

According to a first aspect of the present invention, a welding motor is supplied with a welding motor at a welding speed of about 2 m / min or more to feed a welding wire between a welding wire and a base material. In a consumable electrode type arc welding in which a wire is fed at a speed lower than a steady state at the start of welding, the welding wire is fed after the wire and the base material are short-circuited at the start of welding. After accelerating the speed, after reaching the preset wire feed speed, the speed is reduced to a wire feed speed lower than the preset wire feed speed in steady welding, and further accelerated to the wire feed speed in steady welding. The second invention is characterized in that the consumable electrode type arc welding method is characterized by alternately repeating acceleration and deceleration added to the wire feeding speed.
It is characterized in that the acceleration and deceleration waveforms added to the wire feeding speed are sinusoidal. The fourth invention is characterized in that the maximum wire feeding speed is faster than the wire feeding speed in steady welding.

According to a fifth aspect of the present invention, there is provided a welding power source having a device for controlling a welding current and a welding voltage and detecting a short circuit and an arc generation, and a wire feed speed based on the input short circuit signal and the arc generation signal. A wire feed speed switcher to be switched, a welding initial wire feed speed setting device that presets a wire feed speed from the start of welding to a short circuit between the wire and the base material, and a short circuit between the wire and the base material, Adjustable acceleration and deceleration wire feed speeds are set beforehand, and a welding start wire feed speed setter that repeatedly outputs the accelerated and decelerated wire feed speeds until arcing occurs, and a steady welding A consumable electrode-type arc, comprising: a steady welding wire feeding speed in which the wire feeding speed is set, and a wire feeding motor driven in accordance with the input wire feeding speed. A welding device.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples. First, FIG. 1 is a diagram showing operation timings in the present invention. FIG. 2 is a block diagram of the present invention, and reference numerals 1, 2, 4 to 8 denote the same or corresponding portions as those of FIG. Reference numeral 9 denotes a wire feed speed switch, which outputs a wire feed speed switching signal when a short circuit signal and an arc generation signal are input. Reference numeral 10 denotes an initial wire feed speed setting unit for welding, which presets a wire feed speed from the start of welding to a short circuit between the wire and the base material. Numeral 11 is a welding start wire feed speed setting device, which presets an accelerated and decelerated wire feed speed from a short circuit between the wire and the base material to the occurrence of an arc,
The degree of acceleration and deceleration can be adjusted, and the set accelerated and decelerated wire feeding speed is output until a switching signal due to arc generation is input from the wire feeding speed switch.
Reference numeral 12 denotes a steady welding wire feed speed setting device, which presets a wire feed speed in steady welding.

This embodiment will be described below with reference to the drawings. When a welding start command signal output from an arc welding control device (not shown) is turned on to start welding (t0).
The wire feed speed switch 9 outputs the welding initial wire feed speed set in advance in the welding initial wire feed speed setting device 10 to the wire feed motor, and the wire is fed at the welding initial wire feed speed. You. Until the welding start command signal is turned on and the wire is short-circuited to the base material (from t0 to t1), the wire is sent at the initial wire feed speed, and the initial wire feed speed is higher than the wire feed speed in steady welding. And the short circuit between the wire 6 and the base material 8 is performed smoothly. When a short circuit between the wire 6 and the base material 8 is detected by the welding power source 1 and a short circuit signal is sent to the wire feed speed switch 9,
The wire feed speed is set in advance by the welding start wire feed speed setting unit 1
It is switched to the welding start wire feeding speed set to 1. The welding start wire feeding speed is gradually accelerated in a sine wave form and reaches a preset maximum speed. At this time, the maximum wire feeding speed is set to a speed higher than the wire feeding speed in the steady welding so as not to cause a shortage of the welding amount at the start of welding. In addition, the slope that accelerates does not generate an arc in the middle, there is no force to buckle the wire,
The inclination is such that the wire and the base material can be melted and sufficiently adapted.

As described above, the wire and the base material can be melted and sufficiently blended by increasing the wire feeding speed gradually. Thereafter, the wire feeding speed is gradually reduced in a sine wave shape to promote the burning of the wire and facilitate the generation of an arc. At this time, by setting the minimum wire feeding speed to a speed lower than the wire feeding speed in the steady welding, the wire burns up due to the self-control characteristic of the arc and the arc length gradually increases. The arc stabilizes without plunging. If no arc is generated in the deceleration section, acceleration and deceleration are repeated again to generate an arc. When an arc is generated and the arc generation is confirmed by the welding power source 1, the arc generation signal is turned on (t2), and the arc generation signal is sent to the wire feeding speed switch 9, and the wire feeding speed is set to a predetermined wire feeding speed. After the feed speed is reduced to the minimum speed, the steady welding wire feed speed setting device 12 is set in advance.
The arc length is gradually increased to the arc length in steady welding due to the self-control characteristic of the arc by gradually accelerating to the steady welding wire feeding speed set in the above, so that the arc is stable without the wire 6 sticking into the base material 8. I do.

A welding torch moving device (not shown) moves the welding torch at a welding speed set in a welding speed setting device (not shown) in advance, and steady welding is performed under welding conditions set in a welding condition setting device (not shown). . In this way, the wire 6 and the base material 8 are short-circuited (t1) and the wire feed speed is accelerated and decelerated from the time (t2) to the occurrence of the arc (t2), so that the wire 6 and the base material 8 fit in the acceleration section. Is sufficiently performed to promote the generation of the arc in the deceleration section, thereby stabilizing the arc start, shortening the time until the arc is generated, and improving the working efficiency. Also, after the deceleration section, the arc is stabilized by gradually accelerating to the wire feeding speed in the steady welding, and the transition to the steady welding can be quickly performed. The amount of welding at the start of welding is a region indicated by oblique lines in FIG. 1, and approximately the same amount of welding is obtained as when welding is performed at a wire feed speed in steady welding after the wire 6 and the base material 8 are short-circuited. There is no shortage of welding at the start of welding.

[0013]

As described above, according to the present invention, in welding at a welding speed of about 2 m / min or more, after the wire and the base material are short-circuited at the start of welding, the feeding speed of the welding wire is increased. In addition, since the welding is performed while decelerating and gradually accelerating to the wire feeding speed in the steady welding, the following effects are obtained. (1) It is stable without scattering of molten metal or arc breakage at the time of arc start. (2) The occurrence of the shortage of the welding amount at the welding start portion is improved. (3) The time until the arc is generated is shortened, and the working efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing operation timings in the present invention.

FIG. 2 is a block diagram of an apparatus for implementing the present invention.

FIG. 3 is a block diagram of a conventional welding device.

FIG. 4 is a diagram showing a relationship between a conventional wire feeding speed and a welding voltage.

FIG. 5 is a diagram showing an operation timing in Japanese Patent Application Laid-Open No. 55-126382.

FIG. 6 is a diagram showing operation timings in Japanese Patent Application Laid-Open No. 10-34335.

[Explanation of symbols]

1 welding power supply, 2 wire feeding circuit, 3 sequence control circuit, 4 wire feeding motor, 5 rollers, 6 consumable electrode, 7 welding torch, 8 base metal, 9 wire feeding speed switch, 10 welding initial wire feeding Speed setting device, 11
Welding start wire feed speed setting device, 12 steady welding wire feed speed setting device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Shinji Okumura, 2-1 Kurosaki Castle Stone, Yawatanishi-ku, Kitakyushu City, Fukuoka Prefecture Inside Yaskawa Electric Co., Ltd. (72) Ken Okamoto 2-1 Kurosaki Castle Stone, Yawatanishi-ku, Kitakyushu City, Fukuoka Prefecture F-term in Yaskawa Electric Corporation (Reference) 4E082 AA01 EA02 EB03 EC03 EC13 EC16 EC20 EE10 EF16

Claims (5)

[Claims] 1. A welding method in which a welding motor is fed at a welding speed of about 2 m / min or more by a feed motor to generate an arc between the welding wire and a base material, wherein the wire feeding speed is set at the start of welding. In the consumable electrode type arc welding method of feeding the wire at a speed lower than the steady state, after the wire and the base material are short-circuited at the start of welding, the feed speed of the welding wire is accelerated, and after reaching the preset wire feed speed, A consumable electrode type arc welding method, comprising: reducing the wire feed speed to a wire feed speed lower than a preset wire feed speed in steady welding, and further accelerating to a wire feed speed in steady welding. 2. The method according to claim 1, wherein the feed speed of the welding wire is accelerated and decelerated, and when the wire feed speed in steady welding is increased, if no arc is generated, acceleration and deceleration are alternately repeated. The consumable electrode type arc welding method according to claim 1, wherein 3. The welding wire feeding speed of the welding wire is accelerated, decelerated, and further accelerated to the wire feeding speed in steady welding, wherein the waveform of the welding wire feeding speed is sinusoidal. The consumable electrode type arc welding method according to claim 1. 4. When the feed speed of the welding wire is accelerated and decelerated, and further accelerated to the wire feed speed in steady welding, the maximum welding wire feed speed is higher than the welding wire feed speed in steady welding. 2. The method according to claim 1, wherein the method is fast.
Consumable electrode type arc welding method according to any one of items 1 to 3. 5. A welding power source having a device for controlling a welding current and a welding voltage and detecting a short circuit and an arc generation, and a wire feeding speed for switching a wire feeding speed based on an input short circuit signal and an arc generation signal. A switch, a welding initial wire feed speed setting device for presetting a wire feed speed from the start of welding to a short circuit between the wire and the base material, and an adjustment after the short circuit between the wire and the base material can be adjusted. A welding start wire feed speed setting device that presets accelerated and decelerated wire feed speeds and repeatedly outputs the accelerated and decelerated wire feed speeds until an arc is generated. A consumable electrode type arc welding apparatus, comprising: a steady welding wire feeding speed in which a speed is set; and a wire feeding motor driven in accordance with the input wire feeding speed.