JPS5838673A - Hot wire tig welding machine - Google Patents

Abstract

PURPOSE:To maintain the feed speed for a wire adequately at all times irrespectively of welding currents and to obtain a good bead shape by welding the work at the welding speed in a prescribed range with respect to the feed speed for the wire. CONSTITUTION:According to set arc currents, a function generator 30 sets an adequate feed speed for a wire and a motor 53 is driven according to the set speed, by which a wire 4 is fed to the side of base materials 9. The wire current is so set that the wire just melts and arrives at the materials 9 in accordance with the set feed speed for the wire and the signal for setting said wire current is obtained by conducting the output of the circuit 30 to the inside of a comparator 43 and setting a resistor 45 properly. The setting signal for the wire current is compared with the value obtained by converting the wire current detected by a wire current detector 37 properly to a voltage with an amplifier circuit 38 and a transistor 51 repeats on and off until the wire current value attains a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION Jin's invention relates to a hot wire TIG welding machine that performs welding while also supplying current to a filler wire and preheating it.

The configuration of a conventional hot wire TIG welding machine is as shown in FIG. In fig.

(1) is a torch, (2) a tungsten electrode, (31t
i Power supply for arc current supply, (4) is filler wire (
(hereinafter simply referred to as "wire"), (51a a driving roller for feeding the wire, (6) a power source for heating the wire,
(7) is the arc, (8) is the expanding weld bead, and (9) is the base metal.

1I is a power supply device for supplying current to the wire, and the arrow in Figure 9 indicates the direction of welding progress. The operation of a conventional hot wire TIG welding machine is as follows.

A power source (3) is used to supply current to maintain the arc (7). In addition, the driving roller (n) and the shear wire (4) are connected to the base material (
9), and at the same time, using the power supply (6) to short-circuit the wire (4) and the base metal (9) and simultaneously supply current inside the wire (4), the wire (4) is preheated and the base metal (9) is short-circuited. When it reaches the material (9), it almost melts and becomes a bead and accumulates.

Since the conventional device is configured as described above,
The power source (3) that determines the arc current value and the power source (6) for heating the wire must be adjusted completely independently, and if the amount of wire fed is too large for a certain arc current value (in that case, (4)), the welding bead (8) should be a convex bead with a slight overlap as shown in Fig. 2 (61); conversely, if the wire feed rate is a little too high, An undercut bead as shown in Fig. 2(b) may occur, and if the welding speed is slow, the base metal (9
) The base metal may melt due to too much heat input.

Therefore, it is extremely difficult to adjust the arc current value and the wire feed amount, and it is disadvantageous that it requires skill.

This invention was made to eliminate the drawbacks of the conventional devices as described above, and it always maintains the wire feeding speed at an appropriate level regardless of the welding current.

The object of the present invention is to provide a hot wire T-type G welding machine that can always obtain a good bead shape without dripping or overlap.

The configuration of one embodiment of the present invention is as shown in FIG.

In the figure, an is a power supply for supplying current for wire heating and arc current, al is a detector for detecting the arc current, al is an amplifier circuit for amplifying the output of detector n, and resistor * It consists of a-m, an amplifier aη, etc. Alternatively, resistor 1 is used in the arc current setting circuit for setting the arc current value. Consists of variable resistor (2) and power supply (goods).

(2) is a comparator for comparing the output of the amplifier, line - and the output of the arc current setting circuit axis, and the resistor (2) - (to)
, diodes (goods), etc. An amplifier to amplify the output of @comparator (2), a switching element such as @L transistor, and its ON, 0IFF is an amplifier (to)
controlled by the output of In the cart function generation circuit,
Resistance *a-a, consists of a variable resistor, a power supply, an amplifier, etc. (Goods) is a wire current detector such as a shunt for detecting the current for wire heating. 1w is an amplifier that amplifies the output of the wire current detector (Goods).
- and consists of a resistor alS@f), an amplifier (6), etc.

(to) is a comparator used to compare the output of the amplifier circuit (to) and the output of the function generation circuit (to), and resistor (44) - G!
? ) and a diode-0 amplifier (c). (to) is an amplifier for amplifying the output of comparator tA3, (
51) ti) A switching element such as a transistor changes the wire heating current to 011 according to the output of the amplifier (to).
,0IFF control. Further, (52) is an amplifier t that amplifies the output of the function generating circuit (to). (53) is a wire feeding motor, (54) and (55) are diodes.

(56) (57) It's a beam.

Next, the principle of this invention will be explained.

When the base metal thickness and arc current are constant.

The appearance of the bead changes depending on the welding speed and wire feed rate. The base material has a plate thickness of 32. wire diameter L2so+
When the arc current is 300m and the arc length is 12m,
The wire feeding speed and wire heating current are adjusted so that the wire (4) comes into contact with the base metal (9) in a nearly melted state, and the welding speed and (wire feeding speed)/(welding speed) are adjusted. When the bead shapes are experimentally determined for various combinations, the shapes shown in the regions (a) and (b) in FIG. 4 are obtained.

Note that (wire feeding speed)/(welding speed) indicates the area of the cross section of the extra layer of the bead (in FIG. 2, the area of the bead (8) on the base metal).

The triangular area (a) surrounded by a solid line in Fig. 4 is the base material (9
), where the heat input is appropriate and a stable bead can be formed. In the area shown in (b) of the same figure, the amount of wire feeding is too large, the bead becomes convex, and the bead is connected to the base material (9). In the region (c) of the same figure, which is a region with poor compatibility with (8), the wire feed amount is small and the welding speed is too high.

In the area where undercuts and humping beads appear, the area shown in FIG. 3(d), the welding speed is too slow and the base metal melts down. Once the plate thickness of the base material (9) and the arc current are determined in this way, the relationship between the welding speed and the wire feeding speed at which a stable bead can be formed is determined. On the other hand, considering that the welding speed should be set to an arbitrary value as much as possible for construction purposes, find the appropriate range of wire feeding speed when the thickness of the base material (9) and arc current are determined. . In FIG. 4, the condition when the wire feeding speed is constant is a curve like the broken line in the figure. In welding work, we often use the high-speed welding area (the right part of Figure 4) and the area with a large amount of welding (the upper left part of Figure 4). , wire feeding speed 2shiiH4
, 5" and 4, it becomes k.

Figure 5 shows a plate thickness of 12t using L2ml mild steel wire.
FIG. 2 is a diagram summarizing the results of experimentally determining the appropriate wire feeding speed range for various arc current values for LKTEL WAN M 12 AT.

As can be seen from Fig. 5, if the wire diameter, material, and arc current are determined, the appropriate range of wire feeding speed is between linear M and B when the plate thickness is about L2 m512 W, regardless of the plate thickness. It becomes a sandwiched area. The basic principle of this invention is to set the arc current as described above.

The wire feeding speed must be set so that it always falls within the range determined in FIG. 5, and the circuit for realizing this is a function generating circuit.

The function generation circuit (to) is determined by setting the resistances 0υ and &l.

Figure 5 The slope of the straight line M or B is determined, the power supply (to) and F! By setting the resistance and the variable resistance, the DC component in the vertical axis direction of the line M or B can be set.

Next, the operation of one embodiment of the present invention will be explained with reference to FIG.

First, a required arc current value is set by adjusting a variable resistance within the arc current setting circuit. Then, the arc current detected by the detector (2) is appropriately converted into a voltage signal in the amplifier circuit (2), and compared with the output of the arc current setting circuit in the comparator (2).

From comparator (2).

When the detected arc current is smaller than the set value, a positive output is output, amplified by the amplifier (2), and the switching element 4 is turned on. When the arc current becomes larger than the set value, an output is output from the comparator (2), and the switching element (2) also enters the 0FIF state.

The above operation is repeated and the arc current value becomes the set value. On the other hand, the function generating circuit (to) sets an appropriate wire feeding speed according to the set arc current, and according to the set speed, the motor (53) is driven to feed the wire (4) into the base material ( 9) Sent to the side. Note that the wire current is set so that the wire melts exactly 9 times and reaches the base material (9) in accordance with the set wire feeding speed, but the signal for setting the wire current is generated by the function generating circuit ( It is obtained by guiding the output of The setting signal for that wire current is.

The wire current detected by the wire current detector is compared with the voltage converted by the amplifier circuit.
Transistor (5
1) repeats ON and 0IFF.

Note that at 077 of the transistors (51) and (2), the energy stored in the reactors (56) and <57)jc is released via the diodes (55) and (54), respectively.

This invention includes a means for main controlling the arc current value so that the current value is set, and a wire feeding speed that is predetermined based on the combination of the set current value and the diameter and material of the filler wire used. Since a means for driving the wire feeding device is provided and welding is performed at a welding speed within a predetermined range with respect to the above wire feeding speed, when the arc current is set, the appropriate value of the wire feeding speed is automatically set at the same time. Since the bead shape is selected as follows, there is an effect that a stable bead shape can be obtained with a simple operation.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of a conventional hot wire T-work welding machine, Fig. 92 is a sectional view of a bead, and Fig. 3 is a diagram showing the configuration of a hot wire T-work G welding machine according to an embodiment of the present invention. ,
Figure 4 shows welding speed. FIG. 5 is a diagram showing changes in pead shape for various combinations of (wire feeding speed)/(welding speed), and FIG. 5 is a diagram showing the relationship between arc current and wire feeding speed. In the figure, (l) is a torch, and (2) is tungsten. +31, +6), all is the power supply, (4) is the filler wire, (5) is the drive roller, (7) is the arc,
(8) is the bead, (9) is the base material, (II is the power supply device,
αth is the arc current detector, 01 is the function generation circuit, @,
(51) is a switching element. (53) is a motor. Note that the same reference numerals indicate the same or corresponding parts. Agent Makoto Kuzuno - (1 other person) 111 Figure 1 [Figure 2 Wire feeding, failure ir%] Procedural amendment (voluntary) 2. Name of invention Hot wire TIG welding machine 3. Case of person making amendment Relationship with Patent Applicant Address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mitsubishi Electric Corporation Representative Hitoshi Katayama Department 5, Claims column 6 of the specification subject to amendment, Contents of the amendment (1) The patent claims column of the specification will be corrected as shown in the attached sheet. I List of Attached Documents (1) One or more documents stating the scope of claims for the corrected ridge Claims (1) Means for controlling the arc current value so that it becomes the set current value, and The welding speed is within a predetermined range with respect to the wire feeding speed, and the wire feeding device is driven to a predetermined wire feeding speed based on the combination of the current value and the diameter and material of the filler wire used. A hot wire TIG welder designed to weld with. (2) The hot wire TIG according to claim 1, comprising a function generating circuit that outputs a speed signal for driving the wire feeding device based on a combination of a set current value and the diameter and material of the filler wire used. Welding machine.

Claims (2)

[Claims] (1) A means for controlling the arc current value so as to reach a set power supply value, and a means for controlling the arc current value to a predetermined wire feeding speed based on the combination of the set current value and the diameter and material of the filler wire to be used. A hot wire TIG welding machine, comprising means for driving a wire feeding device, and capable of welding at a welding speed within a predetermined range with respect to the wire feeding speed. (2) The hot wire TIG according to claim 1, which is equipped with a function generating circuit that outputs a speed signal for driving the wire feeding device based on a combination of a set current value and the diameter and material of the filler wire used. Welding machine.