JPH039900Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a welding device for narrow gap, especially for GMA.
Alternatively, the present invention relates to a narrow gap welding device suitable for application to hot wire TIG welding.

[Conventional technology] Due to the demand for thicker steel materials and higher performance of welded joints due to the increase in size of welded structures, the groove width has been narrowed to significantly reduce the groove cross-sectional area. Narrow gap welding has been developed and is widely used for welding large structures because it can be welded with a relatively low heat input, resulting in economical and high-quality welded joints.

The groove shape of narrow gap welding has a width of more than 10 mm on the surface of the workpiece, and a groove angle of 1 to 3 degrees, which is approximately rectangular. Due to these groove shape constraints, welding methods that use slag, such as submerged arc welding, have difficulty in removing slag, so GMA welding, which does not require slag, is widely adopted.
However, even when narrow gap welding is performed using the GMA welding method, the angle between the groove side wall surface and the arc is small, so the groove side wall surface is not sufficiently melted.
There was a problem in that welding defects such as poor fusion occurred near the groove sidewall surface. For this reason, a method was proposed in which the above-mentioned problems were solved by swinging the arc in the width direction of the groove, and the narrow gap welding method came into widespread use.

There are the following methods for moving the arc in the width direction.

(A) As shown in FIG. 7, a method in which the welding torch 71 is tilted left and right with respect to the welding direction with its fulcrum located within the groove. (Unexamined Japanese Patent Publication No. 49-104745
(B) Contact tube 7 as shown in Figure 8.
A method in which the tip of the contact tube 72 is bent at approximately 15 degrees and then turned around or rotated around the axis of the contact tube 72. (Japanese Unexamined Patent Publication No. 49-105742) (C) A bending roll 73 is used to bend the filler wire in a certain direction, and the filler wire 74 is twisted.
(Japanese Unexamined Patent Publication No. 55-45577) (D) The filler wire 74 is deformed into a wave shape by a roll 75 and then supplied to the contact tube 76. (Japanese Patent Publication No. 58-41148) Among the above methods, method (A) is not practical for welding thick-walled materials with deep grooves because the range of arc swing is limited. Methods (B) to (D) are effective, and some have already been put into practical use. In addition, these methods can also deal with fluctuations in groove width that inevitably occur in actual welded structures, such as (B).
This method can be handled by adjusting the amount of reversal and reciprocation.

[Problems to be solved by the invention] However, in the case of conventional narrow gap welding equipment,
The operator continuously monitors the arc and adjusts the swing width of the arc, as well as adjusting the welding torch to the center of the groove, adjusting the welding power source, and adjusting the feed rate of the filler wire. There is an inconvenience in that it requires skill to operate.

In particular, if the groove width is narrow at a certain position P of the weld line as shown in Figure 11, the welding amount will be the same if welded under the same welding conditions, so the stacking height at that part will be different from that of the welding line. be higher than When performing multi-layer welding on thick materials, the stack height in that area becomes significantly higher, which has a negative effect on welding work, so welders need to adjust welding conditions while checking for changes in groove width. be.

The present invention was developed in view of the above-mentioned state of the prior art, and its purpose is to provide a narrow gap welding device that can automatically swing the arc reliably and by an appropriate width. It's there to provide.

[Means for solving the problems] In order to solve the above problems, the present invention
Alternatively, in a hot wire TIG welding device, a contact tube having a tip bent at a predetermined angle, a tip made of a heat-resistant electrical insulator provided at the tip of the tube, a driving means for rotating the contact tube, and the contact tube A control means is provided for detecting that the tip of the contact tube has come into contact with the side wall surface of the groove and reversing the direction of rotation of the contact tube.

[Function] According to the above means, since the contact tube whose tip is bent is rotated and reversed each time it comes into contact with the groove side wall surface, by generating an arc between the filler wire and the workpiece, The arc swings in the width direction of the groove.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a side view showing an embodiment of the present invention.

A shield gas supply pipe 2 is installed on the welding torch support plate 1.
a and 2b are provided, the tips of which are fixed by a fixing plate 3. In order to cool the fixed plate 3, a cooling water supply pipe 4 is installed between the fixed plate 3 and the welding torch support plate 1. Further, a contact tube 5 is provided so as to pass through each of the welding torch support plate 1 and the fixing plate 3, and its tip portion is bent at 45 degrees.

As shown in FIG. 2, the tip of the contact tube 5 is connected with a screw structure to a contact chip 51 into which an alumina ceramic chip 6, which is a heat-resistant electrical insulator, is fitted. The contact tube 5 is inserted from below into a hole provided in the fixing plate 3 and the welding torch support plate 1, and is fixed to the contact tube rotating gear 8 above the welding torch support plate.

A gear 9 fixed to a rotating shaft of a motor 10 meshes with the gear 8 to reduce the rotation speed of the motor 10. In this case, the reduction ratio is set so that the contact tube 5 rotates at a number of more than ten revolutions per minute.

FIG. 3 shows a block diagram of a control circuit for the motor 10. A DC power supply circuit 12 that supplies DC power to the motor 10 is controlled by a forward/reverse control circuit 14. This forward/reverse control circuit 14 includes a drive current detection circuit 13 that detects the drive current supplied to the motor 10.
controlled by.

As shown in FIG. 4, when the contact tube 5 is rotated from the dotted line position to the solid line position by the drive of the motor 10, and its tip contacts the groove side wall surface,
The increase in the drive current at that time is caused by the drive current detection circuit 13
detected by. Based on this detection, the forward/reverse control circuit 14 reverses the voltage magnetism applied to the motor 10 and moves the contact tube 5 from the state shown by the solid line to the state shown by the dotted line. In this way, the tip of the contact tube 5 swings in the width direction of the groove in accordance with the width of the groove. Therefore, the tip of the filler wire 7 fed to the contact tube 5 from a feed roller (not shown) also swings, and as a result, an arc is generated between the filler wire and the workpiece. For example, the arc can swing in the width direction of the groove. The direction of this arc is toward the side wall surface of the groove, and the side wall surface is sufficiently melted.

Next, the dimensions and shape of the tip of the contact tube 5 will be explained.

If the bending angle of the tip of the contact tube 5 is 30 degrees or less, a long ceramic tip 8 of 10 mm or more is required to ensure electrical insulation between the contact tube 5 and the workpiece, which can withstand actual welding work. I couldn't get any chips. On the other hand, if the angle is 60 degrees or more, the feed of the filler wire becomes unstable, so it was found that an angle of 30 to 60 degrees is preferable. Also, regarding the projected length of the curved portion in the tube axis direction, if it is less than 0.7 of the average groove width,
The filler wire came into contact with the side wall surface of the groove before the ceramic chip 8 came into contact with the side wall surface of the groove, resulting in excessive melting into the side wall surface. In addition, the average groove width
When it was 1.5 times or more, the tip of the filler wire did not come close enough to the side wall surface of the groove, and the side wall surface was not sufficiently melted.

FIG. 5 is a block diagram showing the configuration of a control section that controls the welding torch position or welding conditions.

A resistor 15 is provided above the welding torch, and a contact 16 slides on the surface of the resistor in conjunction with the contact tube 5. The output of the contact 16 when the welding torch is at the center is OV, and as the welding torch moves in either direction, the voltage value of the polarity changes depending on the position of the slider 16 that slides. Output from child 16.

A resistance value detection circuit 17 is connected to the slider 16 and converts the input voltage into a resistance value. The resulting resistance value represents the deviation in the amount of left and right rocking of the welding torch and the total amount of rocking.

A welding torch moving motor control circuit 18 , a filler wire feeding motor control circuit 19 , and a filler wire power supply control circuit 20 are connected to the resistance detection circuit 17 . Based on the detected resistance value, the welding torch is moved, the filler wire 7 is fed, and power is supplied to the filler wire 7.

By the control shown in FIG. 5, it is possible to automatically control the position of the welding torch to the center of the groove and to control the amount of welding in response to changes in the width of the groove.

FIG. 6 is a side view showing another embodiment of the present invention. This embodiment is an example of narrow gap welding using hot wire TIG welding, and is constructed by adding a tungsten electrode 24 to the embodiment shown in FIG.

The tungsten electrode 24 is for generating a TIG arc, and is connected to the shield gas supply pipe 2a.
Tungsten electrode support plate 2 fixed to the tip of
3, its tip is fixed. The other end of the tungsten electrode 24 is connected to the welding torch support plate 1
It is connected to a tungsten electrode support rod 22 fixed to the tungsten electrode support rod 22 . Further, instead of the fixing plate 3, a heat-resistant electric insulating fixing plate 22 is used.

Further, the welding torch support plate 1 is provided with an electrical insulator 21 between the tungsten electrode 24 and the filler wire portion in order to electrically insulate the two.

In the configuration shown in FIG. 6, a heating power source having the same polarity as that applied to the tungsten electrode 24 is connected to the filler wire 7. As a result, the arc generated from the tungsten electrode 24 is deflected toward the filler wire 7 due to the magnetic field of the current passed through the filler wire 7. In this way, in addition to the swinging of the filler wire 7 in the groove width direction, it is possible to swing the arc in synchronization with the swinging. The effects obtained by this embodiment are similar to those of the embodiment shown in FIG. 1, and therefore the explanation thereof will be omitted.

[Effects of the invention] As explained above, according to the invention, the arc can be automatically and reliably oscillated by an appropriate width in the width direction of the groove. It can be done without requiring a person.

Further, it is possible to automatically control the position of the welding torch and the amount of welding in response to changes in the groove width. Due to the above synergistic effects, narrow gap welding can be expected to be applied to thick plate structures.

[Brief explanation of the drawing]

Figure 1 is a side view showing one embodiment of the present invention;
3 is a block diagram showing the motor control system, FIG. 4 is an explanatory diagram illustrating the swinging of the contact tube 5, and FIG. 6 is a block diagram of a control system that controls the position of the welding torch and the amount of welding, FIG. 6 is a side view showing another embodiment of the present invention, and FIGS. 7 to 10 are diagrams showing each of the conventional narrow gap welding methods. An explanatory diagram showing an example, FIG. 11, is an explanatory diagram when the groove width is partially narrowed. 1... Welding torch support plate, 2a, 2b... Shield gas supply pipe, 3... Fixed plate, 4... Cooling water supply pipe, 5
... Contact tube, 6 ... Heat-resistant electrical insulator chip, 7 ... Welding wire, 8, 9 ... Gear, 10 ... Motor, 12 ... DC power supply circuit, 13 ... Drive current detection circuit, 14 ... Forward/reverse control circuit, 15 ...Resistor, 1
6...Contactor, 17...Resistance value detection circuit, 18...Motor control circuit for moving the welding torch, 19...Motor control circuit for feeding filler wire, 20...Filler wire power supply control circuit, 24...Tungsten electrode.

Claims (1)

[Claims for Utility Model Registration] (1) In a GMA or hot wire TIG welding device, a contact tube whose tip is bent at a predetermined angle, a tip made of a heat-resistant electrical insulator provided at the tip of the tube, and the A narrow groove characterized by being provided with a drive means for rotating a contact tube, and a control means for detecting that the tip of the contact tube contacts a side wall surface of the groove and reversing the direction of rotation of the contact tube. welding equipment. (2) The bending angle of the tip of the contact tube
The narrow gap welding device according to claim (1) of the utility model registration, characterized in that the angle is within the range of 30 degrees to 60 degrees. (3) The narrow groove according to claim (1) of the utility model registration, characterized in that the projected length of the bent portion in the tube axis direction is set to 0.7 to 1.5 times the average groove width. welding equipment.