JP2005138151A - Welding method and welding system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding method capable of minimizing disturbance of a weld bead by suitably setting the current running in a molten pool. <P>SOLUTION: In this welding method, the electromagnetic force generated by the welding current is applied in the molten metal flowing direction in a molten pool 22b of a weld part by supplying the welding current via a welded member 22 between a welding stage 31 with an electrode side of a welding head II forming a negative pole and a rear side of the welding head II in the traveling direction forming a ground 33 and the electrode by using the welding stage 31 in which a current passing part 31b formed of a member of high conductivity and having a groove part 31a along a weld line 22a of the welding stage 31 is embedded in a body 31c formed of a member of low conductivity via an insulating member 31d. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a welding method and a welding system, and is particularly useful when applied to butt welding thin plates at high speed by hybrid welding such as plasma / arc hybrid welding and laser / arc hybrid welding.

  As a forming material for automobile body panels or the like, tailored blank materials are used in which steel plates having the same thickness or the same material or different steel plates are butted together. In recent years, the welding speed of thin plate butt welding, such as welding for obtaining such tailored blank materials, has been increasingly increasing. For example, laser / arc hybrid welding can be used as a welding head to cope with this high speed. Hybrid welding using a head or the like is often used.

  FIG. 6 is a longitudinal sectional view showing a laser / arc hybrid welding head according to the prior art. As shown in the figure, the tip of the optical fiber 1 is connected to the upper part of the laser / arc hybrid welding head I. The base end of the optical fiber 1 is connected to a YAG laser oscillator (not shown), and the laser light 2 oscillated from the YAG laser oscillator is transmitted through the optical fiber 1 and introduced into the welding head I. It has become.

  The laser beam 2 emitted from the tip of the optical fiber 1 is collimated by the collimating lens group 3 provided in the welding head I, and then half of the laser beam 2 is inclined at 45 degrees with respect to the optical axis direction of the laser beam 2. Is reflected in the lateral direction by the plate-like first reflecting mirror 4 and further reflected downward by the plate-like second reflecting mirror 5 disposed in the same direction so as to face the first reflecting mirror 4 at a predetermined interval. The Thus, the laser beam 2 having a circular cross section is divided into a first divided laser beam 2a and a second divided laser beam 2b having a semicircular cross section, and a space portion is provided between these divided laser beams 2a and 2b. 6 is formed.

  The divided laser beams 2a and 2b are condensed by a condensing lens group 7 provided in the welding head I and irradiated to a member to be welded 8 such as a steel plate. The laser beam irradiation position at this time is indicated by reference numeral 8a in the figure. A bar-shaped arc electrode (arc rod) 10 made of tungsten or the like is disposed in the space 6 between the divided laser beams 2a and 2b, whereby the laser beam 2 (divided laser beams 2a and 2b). And the arc electrode 10 are coaxial.

  The arrangement of the arc electrode 10 can be adjusted as appropriate by an arc electrode adjustment mechanism having an arc electrode position adjustment function, an arc electrode tilt angle adjustment function, and an arc electrode distance adjustment function.

  Further, a frustum-shaped nozzle 12 is attached to the lower part of the welding head I. At the time of welding, an inert gas such as argon gas is introduced into the nozzle 12, and is injected toward the workpiece 8 from the opening 12 a at the tip (lower end) of the nozzle 12.

  The arc electrode 10 is supported in a state of being directed downward at the center of the columnar arc electrode support member 14, and the entire arc electrode portion has a T-shape. The arc electrode support member 14 includes a copper conductive member 11 and a ceramic tube 13 as an electrical insulating material covering the outer periphery of the conductive member 11, and penetrates the nozzle 12 in the radial direction. Yes.

  An electric wire (not shown) is connected to the conductive member 11, and a voltage is applied to the arc electrode 10 from a power source (not shown) via the conductive member 11.

  Butt welding using the hybrid welding head I as described above is performed in a state where a member 22 to be welded such as a steel plate is placed on a welding stage 21 as shown in FIG. That is, as shown in both figures, a groove 21a is formed on the welding stage 21 along a weld line 22a (welding direction (arrow direction in the figure)) formed at the butted portion between the members to be welded 22 below. Further, the groove 21a collects debris that accompanies welding, and prevents the welding of the member to be welded 22 and the welding stage 21 so that good butt welding can be performed. Here, the welding stage 21 is usually formed of a steel material.

  In addition, the following patent document 1 can be mentioned as a well-known technique relevant to this invention.

Japanese Patent Laid-Open No. 2002-18582

  In the butt welding using the welding stage 21 according to the related art as described above, the weld bead is disturbed. This is because the molten metal in the molten pool is agitated by the electromagnetic force acting on the molten pool in the welded portion (the part where the member to be welded has melted and liquefied), and in particular the direction in which the molten metal flows (hereinafter referred to as the flow direction of the molten metal) It is considered that the molten metal is pulled up in the direction opposite to the direction of gravity (upward). Incidentally, since the current is diffused to the welding stage 21 and the member 22 to be welded in the vicinity of the molten pool, an electromagnetic force is generated in various directions according to Fleming's left method rule, and as described above, the direction opposite to the molten metal flow direction. It is thought that it may become an electromagnetic force.

  Such turbulence in the weld pool becomes more prominent as the welding speed increases. This is because the faster the welding speed, the longer the molten pool becomes elongated along the welding direction, and accordingly the molten metal in the molten pool becomes more susceptible to the electromagnetic force acting on this portion.

  Therefore, in order to further increase the welding speed, a countermeasure for reducing the disturbance of the weld bead as described above is desired.

  An object of the present invention is to provide a welding method and a welding system capable of reducing the disturbance of a weld bead as much as possible by setting the current flowing in a molten pool in view of the above-described conventional technology.

  The configuration of the present invention that achieves the above object is characterized by the following points.

1) The member to be welded between a welding stage on which the member to be welded is placed and the electrode on the side of the welding head while the welding head travels along a welding line that is a contact portion between the members to be welded. In a welding method for welding the members to be welded along the weld line by supplying an electric current through
Supplying an electric current so that the electromagnetic force by the said electric current acts in the molten metal flow direction in the molten pool of a welding part.

2) In the welding method described in 1) above,
Insulating the part of the welding stage along the weld line from the other part and using a welding stage having a current passage formed by a member having a higher conductivity than that of the other part. Ground the rear with respect to the traveling direction of the head and, if the electrode side is a positive electrode, perform the welding by grounding the front with respect to the traveling direction of the welding head.

3) In any one of the welding methods described in 1) to 3) above,
Hybrid welding using a hybrid welding head such as a plasma welding / laser / plasma hybrid welding head or a laser / arc hybrid welding head as the welding head.

4) In a welding stage for placing the members to be welded in welding for welding the members to be welded while running a welding head along a welding line that is a contact portion between the members to be welded,
A portion along the weld line is insulated from other portions and has a current passage portion formed of a high conductivity member, the welding stage side is a positive pole, and the welding head side electrode is a negative pole; and In any case where the welding stage side is a negative pole and the welding head side electrode is a positive pole, the rear of the current passage portion is grounded with respect to the traveling direction of the welding head and melted during welding. It was configured to supply a current that causes electromagnetic force to act in the hot water flow direction in the pond.

5) In the welding stage described in 4) above,
The current passage portion is made of a copper material, and the current passage portion is embedded in another member via an insulating member.

6) The welding stage described in the above 4) or 5) is combined with a welding apparatus having a welding head, its traveling system, and a control system for the entire apparatus.

7) In the welding system described in 6),
The welding apparatus is a hybrid welding apparatus using a hybrid welding head such as a plasma welding / laser / plasma hybrid welding head or a laser / arc hybrid welding head as the welding head.

  According to the present invention configured as described above, the following effects are obtained.

Since the invention described in claim 1 has a configuration as described in 1) above,
Electromagnetic force in the hot water flow direction acts on the molten metal in the molten pool, and the molten metal is pulled in the hot water flow direction. Therefore, stirring of the molten metal in the molten pool is suppressed, and a high-quality weld can be formed as a weld bead with a beautiful finish.

Since the invention described in claim 2 has a configuration as described in 2) above,
The welding current concentrates through the current path and not only the current in the molten pool is set in a certain direction but also the electromagnetic force acting on the current flowing through the molten pool is in the direction of the molten metal flow, so that the molten metal is disturbed. A beautiful weld bead is formed along the weld line.
As a result, a high-quality weld can be formed.

Since the invention described in claim 3 has a configuration as described in 3) above,
In particular, it is possible to form a weld of good quality even in hybrid welding where the welding speed is high and disturbance of the weld bead is likely to occur.

Since the invention described in claim 4 has the configuration as described in 4) above,
The welding current concentrates through the current path and not only the current in the molten pool is set in a certain direction but also the electromagnetic force acting on the current flowing through the molten pool is in the direction of the molten metal flow, so that the molten metal is disturbed. A beautiful weld bead is formed along the weld line.
As a result, a high-quality weld can be formed.

Since the invention described in claim 5 has a configuration as described in 5) above,
It is possible to easily form a high conductor current path through which a welding current flows intensively.

Since the invention described in claim 6 has the configuration as described in 6) above,
The welding system which has an effect | action and effect described in Claim 4 or Claim 5 can be provided.

Since the invention described in claim 7 has a configuration as described in 7) above,
In particular, it is possible to provide a welding system in which a weld of a good quality is formed even in hybrid welding where the welding speed is high and the weld bead is likely to be disturbed.

  FIG. 1 is a perspective view showing a welding system according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an aspect during welding in the welding system shown in FIG.

  As shown in both figures, the welding system is configured such that the welded members 22 are connected to each other while the welding head II travels in a direction indicated by an arrow in the drawing along a weld line 22a that is a contact portion between the welded members 22. Are butt welded. Here, the welding apparatus including the welding head II further includes a traveling system of the welding head II, an overall control system, and the like (both not shown).

  A welding stage 31 on which the member to be welded 22 is placed at the time of welding has a current passage portion 31b formed of a highly conductive member by insulating the portion along the weld line 22a from other portions. Here, a groove 31a having the same function as the groove 21a shown in FIGS. 7 and 8 is formed in the current passage portion 31b, and the insulating member 31d is attached to the main body 31c formed of a relative low conductivity member or the like. It is buried through. Therefore, the welding current at the time of welding flows intensively through the current passage portion 31b. As a result, the welding current can be confined in a narrow range and intensively flowed in one direction, and the current flowing through the molten pool 22b, which is the welded portion of the member to be welded 22, can be set in a predetermined direction.

  In this embodiment, the rear side of the current passage portion 31b is grounded 33 with respect to the traveling direction of the welding head II. This is because the welding head II in this embodiment is a case where the electrode is a negative pole and the welding stage 31 is a positive pole.

  In this embodiment, the welding current during welding flows intensively in the current passage portion 31b of the welding stage 31. That is, as shown in FIG. 3, it reaches from the ground 33 to the arc electrode 34 through the current passage portion 31b and the molten pool 22b. Therefore, in this case, a magnetic field B as shown by a ring-shaped arrow is formed in the arc 35 reaching the current passage portion 31b and the arc electrode 34 according to the right-handed screw law. As a result, the magnetic flux B obtained by combining these becomes a direction parallel to the surface of the member 22 to be welded. Therefore, a downward force F in the figure acts on the current I flowing in the molten pool 22b by the magnetic field B according to Fleming's left method rule. This force F is the direction of gravity, that is, the hot water flow direction. Therefore, according to the present embodiment, the welding speed becomes high, and even if the shape of the molten pool 22b is elongated in the traveling direction of the welding head II, the molten metal is excellent in the gap between the butted portions of the welded members 22. A beautiful weld bead is formed.

  FIG. 4 is a weld bead when welded by the welding system according to the present embodiment, and FIG. 5 is an explanatory view showing a photograph of the shape of the weld bead when welded by the welding system system according to the prior art in a plan view. In both figures, 22 is a member to be welded, and 36 and 16 are weld beads. While the weld bead 16 shown in FIG. 5 causes humping and disturbance of the weld bead 16, the weld bead 36 shown in FIG. 4 has a beautiful shape without causing such humping and disturbance. Is clearly understood.

  Even when the electrode on the welding head II side is a positive electrode and the welding stage 31 side is a negative electrode, the rear of the current passage portion 31b is grounded with respect to the traveling direction of the welding head II. In this case, the direction of the current is reversed with respect to the above embodiment, but the direction of the magnetic field is also reversed at the same time, so the direction of the electromagnetic force is the hot water flow direction as in the above embodiment. Therefore, a clean weld bead can be formed as in the above embodiment.

  Further, Patent Document 1 describes that in hybrid arc / laser welding, the force based on the induction electromagnetic field is balanced, but this is configured so that a welding current flows through the earth contactor 10. In this way, the current flowing through the molten pool is suppressed, so that the molten metal in the molten pool is not affected by the electromagnetic force. Therefore, as described above, the force based on the induction electromagnetic field is reduced and balanced.

  On the other hand, in this invention, the welding current of a predetermined direction is actively sent through the molten pool 22b, and the electromagnetic force by this is made to act on the molten metal flow direction, and it is made to enter into the clearance gap of the butt | matching part of the to-be-welded member 22. . This can further stabilize the bead shape.

  In this embodiment, the current passage 31b of the stage 31 is made of copper and the main body is made of steel. According to the present embodiment, the current passage portion 31b is formed with copper having high conductivity, and the main body, which is the other portion, is formed with a steel material lower than that, so that the welding current is concentrated on the current passage portion 31b. be able to.

  In this example, a hybrid welding system having a hybrid welding apparatus in which the welding head II is formed of an arc / laser hybrid welding head similar to that shown in FIG. 6 was constructed. According to this example, in high-speed hybrid welding with a welding speed of about 5 m / min, it is possible to improve the welding quality while maintaining a high welding speed with good working efficiency.

  Needless to say, the welding head need not be limited to the hybrid type. As long as welding using current is performed, the present invention can be applied without particular limitation, and the same effect can be obtained. For example, it can be similarly applied to plasma welding or the like.

  The present invention is useful when applied to, for example, tailored blank welding in the automobile industry.

It is a perspective view which shows the welding stage of the welding system which concerns on the Example of this invention. It is a perspective view which shows the aspect at the time of welding in the welding system which has the welding stage shown in FIG. It is explanatory drawing for demonstrating the electromagnetic force which acts on a molten pool at the time of the welding shown in FIG. It is explanatory drawing which shows the mode of the welding part of the to-be-welded members welded with the welding system which concerns on the Example of this invention seeing planarly. It is explanatory drawing which sees the mode of the welding part of the to-be-welded members welded with the welding system which concerns on a prior art in planar view. It is a longitudinal cross-sectional view which shows the laser / arc hybrid welding head used for hybrid welding. It is a perspective view which shows the welding stage of the welding system which concerns on a prior art. It is a perspective view which shows the mode at the time of welding in the welding system which concerns on the prior art which has the welding stage shown in FIG.

Explanation of symbols

II Welding head 22 Welded member 22a Welding line 22b Weld pool 31 Welding stage 31a Groove 31b Current passage 31c Body 31d Insulating member 33 Earth 34 Arc electrode 35 Arc 36 Weld bead I Current B Magnetic flux F force

Claims (7)

While moving the welding head along a welding line that is a contact portion between the members to be welded, the welding member is interposed between the welding stage on which the member to be welded is placed and the electrode on the welding head side. In a welding method for welding the members to be welded along the weld line by supplying current,
A welding method comprising supplying an electric current so that an electromagnetic force due to the electric current acts in a molten metal flow direction in a weld pool of a welded portion. The welding method according to claim 1,
Insulating the part of the welding stage along the weld line from the other part and using a welding stage having a current passage formed by a member having a higher conductivity than that of the other part. A welding method comprising grounding the rear with respect to the traveling direction of the head and grounding the front with respect to the traveling direction of the welding head when the electrode side is a positive electrode. The welding method according to any one of claims 1 to 3,
A welding method characterized by performing hybrid welding using a hybrid welding head such as a plasma welding / laser / plasma hybrid welding head or a laser / arc hybrid welding head for the welding head. In a welding stage for placing the members to be welded in welding for welding the members to be welded while running a welding head along a welding line that is a contact portion between the members to be welded,
A portion along the weld line is insulated from other portions and has a current passage portion formed of a high conductivity member, the welding stage side is a positive pole, and the welding head side electrode is a negative pole; and In any case where the welding stage side is a negative pole and the welding head side electrode is a positive pole, the rear of the current passage portion is grounded with respect to the traveling direction of the welding head and melted during welding. A welding stage configured to supply an electric current for applying an electromagnetic force in a hot water flow direction in a pond. The welding stage according to claim 4,
A welding stage characterized in that the current passage portion is formed of a copper material, and the current passage portion is embedded in another member via an insulating member.   6. A welding system comprising a combination of the welding stage according to claim 4 and a welding apparatus having a welding head, a traveling system thereof, and a control system for the entire apparatus. The welding system according to claim 6,
The welding system is a hybrid welding apparatus using a hybrid welding head such as a plasma welding / laser / plasma hybrid welding head or a laser / arc hybrid welding head as a welding head.

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