JP5124765B2 - Welding method and welding apparatus using electromagnetic force - Google Patents

Description

  The present invention relates to a welding method and welding apparatus using electromagnetic force, and more particularly, in fusion welding such as arc welding and laser welding, while reducing the adverse effect of gravity on weld bead formation and metallurgical performance during solidification. The present invention relates to a method for providing a means for preventing deterioration and enabling high-efficiency and high-quality construction.

  In fusion welding such as arc welding and laser welding, there has been a problem that the molten metal flows downward due to gravity, and shape defects such as undercuts and overlaps and concomitant fusion defects are likely to occur. In particular, in reverse wave welding without using a backing material (to obtain a bead that is constructed from one side and completely melts to the back side of the base material), undercut defects occur on the top surface of the base material during upward and downward welding, and the bottom part There are many problems in practical use, such as excessive bead formation and the formation of backside bead tends to become unstable due to disturbance. In addition, the fusion weld has inherent metallurgical problems such as hot cracking, crystal coarsening, and pore generation during solidification, and there is a problem that joint quality is greatly lowered depending on the material used.

  In order to solve this, the present inventors have formed a unidirectional current in the molten pool, applied a DC magnetic field to generate a unidirectional electromagnetic force, and a method for controlling the bead shape of the weld ( Patent literature 1) is proposed, and a paper is published as a unique weld pool magnetically controlled welding method (non-patent literature 1 and 2). These methods install a magnetizing coil coaxial to the welding torch, apply a DC magnetic field orthogonal to the unidirectional current in the weld pool, obtain an electromagnetic force in the upward direction, and mainly improve the bead shape of the weld. It is intended.

Japanese Patent Laid-Open No. 10-286670 Journal of High Temperature Society, Vol. 25 (1999), no. 5, 211-218 Journal of the Japan Welding Society, Vol. 18, (2000), no. 1,40-50

  However, although the welding method described in Patent Document 1 enables molten metal flow control using a DC magnetic field, no promising solution has been proposed for other problems. In particular, there is no effective method that can simultaneously solve bead shape control, shape defect prevention, bead formation stabilization, and metallurgical problems.

  In arc welding, the penetration depth is almost uniquely determined by the heat input, speed, arc current waveform, etc. during welding, and the penetration depth is actively determined while keeping these parameters constant. There was no means to control. In laser welding, the penetration depth is almost determined by the laser output, optical system, welding speed, etc., and there is no means for actively controlling the penetration depth while keeping these parameters constant. Both were major industrial challenges.

  Accordingly, an object of the present invention is to provide an effective welding method and welding apparatus capable of simultaneously solving bead shape control, shape defect prevention and metallurgical problems in fusion welding such as arc welding and laser welding.

According to the first aspect of the present invention, in welding in a downward posture or an upward posture, an energy bundle is charged or irradiated to face the material to be welded to form a molten pool in the material to be welded and added to the molten pool. A heating current is passed through the weld pool via a wire, and includes a DC magnetic field component in a direction parallel to the surface formed by the base material and intersecting the weld line, and the time on the positive side differs from the time on the negative side. a welding method, characterized in that the peak value of the peak value and the negative side is applied a magnetic field that varies as different asymmetrical AC.

According to the second aspect of the present invention, in welding in a downward posture or an upward posture, an energy flux is input to face the material to be welded to form a molten pool, and a heating current is supplied via a wire added to the molten pool. Is applied to the molten pool to form a highly directional current in the molten pool, and includes a DC magnetic field component, and the positive time and the negative time are different or the positive peak value and the negative peak value. Welding characterized in that an electromagnetic force is generated in the molten pool by applying a magnetic field that fluctuates as a different asymmetrical alternating current in a direction that is substantially parallel to the surface of the material to be welded and intersects the current or energy flux in the molten pool Is the method.

Invention of Claim 3 is a welding method in any one of Claims 1-2 which keeps a to-be-welded material and a magnetic pole at a fixed space | interval, and keeps a molten pool and a magnetic pole at a fixed distance.

The invention according to claim 4 is the welding method according to any one of claims 1 to 3 , wherein the molten metal is flow-controlled by a unidirectional electromagnetic force generated by a direct current component magnetic field.

The invention described in claim 5 is the flat position or upward position welding, arc times and different or positive time a DC component in the direction of direction substantially perpendicular toward the base material of the unrealized positive and negative grant field peak value of the peak value and the negative side is varied as different asymmetrical AC is arc welding method characterized by vibrating and / or deflection in the welding line direction arc with electromagnetic force.

The invention according to claim 6 is an arc according to claim 5 , wherein the arc is flattened by electromagnetic force so that the heat source is distributed long in the weld line direction on a time average and narrowly distributed in the direction perpendicular to the weld line. It is a welding method.

The invention according to claim 7 is an asymmetry in which the positive time and the negative time are different or the positive and negative peak values are different in a direction substantially orthogonal to the direction of the arc toward the workpiece. The arc welding method according to claim 1, wherein a magnetic field that fluctuates as an alternating current is applied , and the arc and the molten metal are simultaneously electromagnetically driven.

The invention of claim 8 is the arc welding apparatus for forming a molten pool by generating an arc opposite the workpieces in flat position or upward position welding, and a positive time and negative-side time Different or positive peak value and negative peak value are different as asymmetrical alternating current and a magnetizing power source and an opposing magnetic pole in the vicinity of the molten pool, the positive time and the negative time are different or positive The positive and negative times supplied from the magnetized power supply vary as asymmetrical alternating currents that have different peak values and negative peak values. The asymmetrical alternating currents have different positive and negative peak values. in arc welding apparatus is characterized in that so as to apply a magnetic flux generated from the said opposite magnetic poles in a direction which intersects the current through the arc and / or molten pool by a current which varies as a That.

The invention according to claim 9 has a discharge mechanism such as an arc or corona discharge and / or a mechanism for directly energizing the vicinity of the molten pool in welding in the downward posture or the upward posture, and is applied while supplying current to the molten pool. In laser welding equipment that forms a weld pool by irradiating a welding beam with a laser beam, the positive time and the negative time including the DC component are different, or the positive peak value and the negative peak value are different. An opposing magnetic pole is provided in the vicinity of the magnetizing power source that fluctuates as an alternating current and the molten pool, and the positive side time and the negative side time are different, or the positive side peak value and the negative side peak value vary as asymmetrical alternating currents. generation of the from the opposite pole by a current peak value of the time of the positive-side supplied from the magnetization power supply and the negative side of the time are different or peak value of the positive and negative is varied as different asymmetrical AC A laser welding apparatus, characterized in that the magnetic flux was exert in the direction to cross the current of the discharge or the molten pool.

  In the present invention, the alternating magnetic field means a waveform such as a general sine wave, a rectangular alternating current shown in FIG. 3 and a mixed waveform thereof, and a magnetic field having a waveform that changes with a constant variation rule over time. It means everything.

  The present invention generates an electromagnetic force that fluctuates in the thickness direction in the molten pool due to the interaction between the alternating magnetic field component and the unidirectional current component, and prevents cracking by preventing crystal refinement and segregation by the forced flow action of the molten metal. Degassing effect is obtained. In addition, the subtle wetting phenomenon of the back bead forming portion can be stabilized by vibration in the plate thickness direction, and instability due to changes (disturbances) in the surface condition, wire feed speed, wire supply position, etc. can be improved. Furthermore, the interaction between the DC magnetic field component and the one-way current generates an electromagnetic force that controls the flow of the entire molten metal in one direction, and the bead shape can be controlled. The magnetic field component leaking near the weld pool (the magnetic field component orthogonal to the arc) generates an electromagnetic force that vibrates and / or deflects the arc in the weld line direction, and the arc heat source is long in the weld line direction. As a phenomenon occurs, the penetration width is reduced, and a preferable unexpected effect of increasing the penetration depth is also obtained. As described above, the present invention can simultaneously obtain many effects such as improvement of the heat source form, improvement of the bead shape, stabilization of bead formation, and improvement of metallurgical performance.

  In addition, the present invention provides a new means for controlling the penetration depth of the welded portion, extends the limits of conventional welding methods, and is beneficial for improving productivity and quality. Furthermore, the present invention can be widely used for improving production methods of energy equipment such as power generation facilities, transport equipment such as aircraft and automobiles, large structures, and various large machines.

  Hereinafter, arc welding according to the present invention will be described with reference to the drawings. However, the present invention is not limited to arc welding, and can be widely applied to fusion welding such as laser welding by adding means for supplying current. is there.

In FIG. 1, an arc welding apparatus of the present invention includes a welding electrode 2 connected to a welding power source 1, an additive wire 4 connected to an additive wire power source 3, and a magnetizing coil 6 connected to an asymmetrical AC magnetizing power source 5. And an iron core 7 for guiding the magnetic flux to a predetermined portion.
An arc 9 is generated from the tip of the welding electrode 2 to a material to be welded (hereinafter referred to as a base material) 8 to form a molten pool 10. The welding electrode 2 may be a non-consumable electrode such as TIG welding or a consumable electrode such as MAG welding. Here, an example of TIG welding is illustrated. The welding electrode 2 is usually shielded by a shield nozzle, but since it has a general structure, the shield nozzle is not shown. The additive wire 4 is continuously fed by the wire feeding device 11. The iron core 7 is divided into two ends, and the left pole in the figure is 7a and the right pole is 7b.
The welding electrode 2, the additive wire 4 and the magnetic pole 7 are fixed at their relative positions by an appropriate fixing device, and are mounted on a mechanism capable of moving on the base material while keeping the relative position constant.
The magnetic pole 7 is molded into an appropriate shape and is disposed so as not to interfere with the proper arrangement of the welding electrode 2 and the additive wire, and has a normal geometric arrangement suitable for welding work.
A wheel mechanism 15 is installed at the tip of the magnetic poles 7a and 7b, and is structured to be able to move smoothly while keeping a slight gap between these magnetic poles and the base material constant. The magnetic pole is pressed against the base material surface by a drive mechanism (not shown) such as an air cylinder so as to maintain a constant height. The gap may be controlled by detecting a certain distance with a sensor.

  As shown in the cross-sectional view in the vicinity of the molten pool in FIG. 2, the pair of magnetic poles 7a and 7b are opposed to each other with the molten pool 10 interposed therebetween. Therefore, a nonmagnetic metal such as austenitic stainless steel is used as a base material. If the magnetic flux 12 leaks from one magnetic pole, the magnetic flux 12 that passes through the base material 8 and the molten pool 10 and is recovered by the counter magnetic pole, or passes through the air and passes through the arc portion 9 to counter the counter magnetic pole. There is also a magnetic flux 12 recovered. Even when a ferromagnetic material such as steel is used as the base material, the effect of the present invention can be sufficiently exhibited, and will be described in a later example.

The magnetizing power source 5 can generate an asymmetrical AC magnetizing current as shown in FIG. 3, and can adjust the peak current value Ic of the magnetizing current, the ratio of the positive time 24tp to the negative time 25tn of the magnetizing current, and the AC frequency F. The structure is adopted, and the peak current value Ic, the frequency F and the following asymmetry rate Dr can be arbitrarily adjusted as appropriate according to the welding conditions. Here, the fact that the symmetry rate can be adjusted arbitrarily means that a direct current can flow when the symmetry rate Dr = 0 or 1, and a symmetrical alternating current (an alternating current not including a direct current component) is obtained when the asymmetry rate Dr = 0.5. It means that it can flow. From this, the asymmetrical AC magnetized power supply is defined as a power supply that can arbitrarily adjust from direct current to alternating current. In addition, since the generation method and apparatus structure of an asymmetrical alternating current are well-known techniques and there are commercial products, description is abbreviate | omitted.
In FIG. 3, the asymmetry ratio 20Dr of the magnetizing current is defined as Dr = tp / (tp + tn), and the positive current 21 and the negative current 22 flow according to this time ratio. Here, when the positive electrode current 20 between tp and the negative electrode current 21 between tn are time-averaged, the recognized DC component Iav = Ic · (tp−tn) / (tp + tn) is defined as the DC component 23Iav.
When such a magnetizing current flows through the magnetizing coil, a magnetic field substantially corresponding to this current waveform is formed in the vicinity of the molten pool from the tip of the magnetic pole, and electromagnetic force (Lorentz force) is generated by the interaction with the arc and the current in the molten pool. And occurs in the molten pool.

  The present invention can be applied not only to arc welding but also to laser welding. A laser beam is irradiated instead of the welding electrode 2 and the arc 9 in FIG. 1, and a molten pool 10 is formed in the base material 9 using this as a melting heat source. Although the laser beam is not accompanied by an electric current, since a heating current is applied to the wire added to the molten pool, an electric current exists in the molten pool. By applying a magnetic field in a direction parallel to the base material to this current, an electromagnetic force is generated by the interaction with the orthogonal current. Since this electromagnetic force is an electromagnetic force in the plate thickness direction, a forced flow force in the plate thickness direction is generated in the molten pool, and the effect of increasing or decreasing the penetration depth is exhibited. In the case of combined hybrid welding using both an arc and a laser as a heat source, the same action as described above occurs.

Example 1
The arc welding apparatus shown in FIG. 1 is used, and SUS304 having a thickness of 3 mm as a base material and a torch minus polarity (minus polarity means a current collector). Welding conditions are TIG welding arc current 155A, welding speed 12cm / min, wire polarity plus, wire feed speed 1.4m / min, wire heating current 60A, magnetizing current peak current 0.5A, frequency 5Hz, asymmetry rate Back wave welding was performed in a downward posture at Dr = 0.75. The results are shown below.

<Generating action of electromagnetic force>
As an example, when the electrode 2 is connected to a negative polarity by TIG welding, the additive wire 4 is connected to a positive polarity (corresponding to a power feeding device). As a result, a one-way current 16Id is formed between the arc and the additive wire in a macro view. On the other hand, when the asymmetrical AC magnetizing current 26Idr is passed through the magnetizing coil 6, an asymmetrical AC magnetic field substantially proportional to the magnetizing current waveform shown in FIG. Due to the interaction between the magnetic field and the one-way current 16Id, the time for generating the electromagnetic force 13Fu for driving the molten metal upward as shown in FIG. 4 (enlarged view of the molten pool portion) is long, and the molten metal is driven downward. An asymmetrical fluctuating electromagnetic force (Lorentz force) is generated with a short time for generating the electromagnetic force 14Fd.
The molten metal is forcibly vibrated in the plate thickness direction (vertical direction in FIG. 4) by these electromagnetic forces. However, if the time 24tp at the time of the positive pole of the left magnetic pole 7a in FIG. The upper electromagnetic force 13Fu becomes dominant, and the entire molten metal is pushed upward while vibrating vertically.
When attention is paid to the arc, the orthogonal magnetic flux 12 similarly fluctuates with time, so in FIG. 4, the electromagnetic force 30Fl for driving the arc to the left and the electromagnetic force 31Fr for driving the right are alternately generated. The arc is deflected left and right in the direction of the weld line. As a result, when viewed on a time average, the arc has a distribution stretched in the direction of the weld line, but an action that has a distribution biased to the right according to the time ratio of the magnetizing current occurs.

<Welding phenomenon and heat source shape improvement effect: Bead shape control effect>
In normal welding without applying a magnetic field, as shown in FIG. 5A, the arc 9 has a symmetrical bell shape, and the arc leg 9A is widened. On the other hand, when an asymmetrical alternating magnetic field is applied, when viewed from the weld line direction, the legs of the arc 9B become narrower as shown in FIG. 5B, and the contraction is about 1/2 to 2/3 of 9A. doing.
Judging from this phenomenon and the arc phenomenon observed from the direction orthogonal to the weld line, the present invention can determine that the arc 9 is long in the weld line direction and narrows in the weld width direction. This effect of improving the heat source shape can be expected to have a favorable effect in the arc welding process, such as reduction of the bead width, prevention of melt-down caused by this, and enabling high-speed welding by dispersion of arc pressure.

<Illustration of welding results>
FIG. 6A is a cross-sectional macrophotograph of a welded part in an experimental condition where a magnetic field is not applied in the above welding condition example. Under such welding conditions, a wide undercut 40, which is a kind of welding defect, is formed on the upper surface of the bead, and the back bead width and bead height are excessive, resulting in an unacceptable industrial welding result.
On the other hand, in the present invention, as shown in FIG. 6 (B), the bead width is generally reduced, an appropriate surplus is formed on the upper surface of the bead, and a back wave is formed on the back surface. Good joints without defects are obtained. In this embodiment, the front bead width is reduced by 20% when a magnetic field is applied, and the back bead width is reduced by 35%. Such an effect of reducing the weld bead width is considered to be due to the improvement effect of the heat source shape.

<Action and effect on molten metal>
When the electromagnetic force is positive, the molten metal is forced to flow upward and has a convex shape upward. When the electromagnetic force is negative, the molten metal is forced to flow downward and has a convex shape. However, it is set as a condition that it does not melt down due to gravity and downward electromagnetic force. In the present embodiment, since the asymmetrical magnetization current is applied in the positive direction, the period of the positive electromagnetic force is long, and the electromagnetic force that flows upward is dominant on the time average.
As the solidification progresses while repeating this, a bead shape controlled to be pushed upward as shown in FIG. 6B is formed, the undercut is eliminated, and a significant bead improvement effect is recognized.

<Solidification crystal refinement effect>
When there is no electromagnetic force vibration, solidification starts from the bond portion 41 (indicated by the dotted line in the figure) after passing through the arc, solidification progresses toward the center of the molten pool, and is elongated and coarse as shown in FIG. 6 (A). Columnar crystals 42A are generated. In the figure, an example of the outline of a coarse crystal is shown for reference. In the center of the weld zone, coarsened crystals are linearly associated with each other, and although they do not crack, microscopic defects are likely to occur, and metallurgy such as toughness, high-temperature creep strength, and embrittlement during use. This is not a preferable state from the viewpoint.
On the other hand, in FIG. 6 (B) which is the welded portion of the present invention, welding is performed under exactly the same conditions except for the magnetic field condition, but the solidified crystal generally has a strong tendency to refine in the joint portion, Even the relatively large columnar crystal 42B in FIG. 6B is significantly miniaturized to about 1/3 to 1/4 as compared with the conventional method. In addition, a large number of small equiaxed crystals are generated at the center of the weld bead.
As a result, many effects such as reduction of microvoids, reduction of segregation, prevention of cracking in a material having a high solidification cracking sensitivity, and reduction of anisotropy of the weld metal can be expected.

This is caused by the asymmetrical electromagnetic force generated by the interaction between the asymmetrical AC magnetic field shown in FIG. 3, the arc current in the molten pool, and the added wire current, causing the molten metal to flow in the plate pressure direction (in this experiment, the flow is reversed up and down). Forced to flow, (1) Electromagnetic force or forced flow force perpendicular to the dendritic crystal to grow in the plate width direction acts, and this tip is bent to suppress crystal growth. (2) Since the broken fine crystal fragments are dispersed in the molten pool and act as solidification nuclei, the number of crystals is further increased, resulting in the suppression of the growth size per piece. (3) Magnetic field on both front and back surfaces of the molten pool It is clearly observed that it vibrates up and down almost in synchronization with the frequency, and for each vibration, the hot molten metal fluctuates up and down, and the action of changing the direction of heat flow occurs, suppressing crystal growth. It is thought that the effect to do occurs.
From this point of view, a new action of reversal flow in the thickness direction, which is not present in the conventional magnetic stirring (rotation in the molten pool surface), is generated from the viewpoint of the miniaturization effect. In addition, by applying a magnetic field frequency near the natural frequency of the molten pool itself, the amplitude in the plate thickness direction vibration can be increased, and there is a feature that it is easier to obtain a vibration effect than the conventional in-plane rotation.

<Stabilizing effect for improving the back bead shape>
FIG. 7 (A) shows the result of similar welding using a DC magnetic field according to Patent Document 1 of the present inventors. As a result, the effect of improving the front bead shape can be obtained, but there is a problem that the formation of the back bead tends to be unstable. In the experiment shown in FIG. 7A, when welding is performed by continuously changing the magnetizing current, the abrupt back wave bead width locally increases or decreases in the unstable part (in the broken line part in FIG. 7A). Has problems such as the disappearance of the back bead and the occurrence of defective fusion.
On the other hand, FIG. 7B, which is an embodiment of the present invention, smoothly follows a similar change in magnetizing current and has very good stability against disturbance. As a cause of this, in the present invention, the high-temperature molten metal is forced to flow downward by electromagnetic force in the plate thickness direction, so that an action of increasing the penetration force of the penetration occurs, and a stable melting effect on the back side is expressed. Conceivable. Moreover, the heat source form distributed long in the weld line direction also has a favorable influence, and the effect of stabilizing the back bead against disturbance is greatly improved by the combined effect of the electromagnetic force in the plate thickness direction and the heat source form.

<Prevention of segregation and solidification cracking>
Segregation is prevented by the forced flow effect due to electromagnetic force, and the number of solidified crystals is increased by the crystal refining effect, so that small crystals in which low melting point impurities such as P and S and substances that are easily segregated such as Mo are refined. It is dispersed in between, making it difficult to concentrate in the final solidified portion of the bead (mostly the central portion of the weld bead), and solidification cracking can be prevented.

<Degassing effect>
Due to the vertical vibration caused by electromagnetic force, the gas components absorbed in the supersaturation in the molten metal were forcibly purged, and the effect of preventing blowholes was observed. In particular, the degassing effect is more conspicuous than the conventional magnetic stirring method because the increase due to the buoyancy of the gas is accelerated during upward vibration.

Example 2
In addition to the time ratio adjustment as shown in FIG. 3, it was confirmed that the asymmetrical alternating current can obtain the same effect by changing the peak value of the magnetizing current at the time of the positive electrode and that of the negative electrode.

  The conditions of Example 1 are only an example of experiments conducted, and the present invention can stably ignite an arc in the commonly used TIG, MAG, MIG, and submerged welding methods. In the range of arc current, welding speed, and groove shape, the effect of the present invention can be exhibited regardless of the welding posture. In particular, if the welding depth is a combination of welding conditions in which the penetration depth penetrates almost to the back surface in reverse wave welding, it is possible to obtain the control and stabilization effect of the reverse wave bead shape regardless of the thickness and type of the base material. In addition, it has been confirmed that the effects of control, stabilization, and metallurgical improvement of the surface bead shape can be obtained also in the welding after the second layer.

  However, when aiming at the refinement effect of the solidified crystal, the frequency of the magnetizing current is 1.5 to 2 times the natural frequency determined by the weld pool shape / size, surface tension, and density formed under the welding conditions. If it is in this range, the vibration of the molten metal can follow the electromagnetic force vibration, and this effect can be obtained. If the asymmetry ratio is greater than 0 and less than 1, the bead shape control and the beat shape stabilization, the solidification crystal refinement, the degassing effect, and the prevention of solidification cracking which are the object of the present invention are provided. Can be obtained according to the application.

  Further, in the case of a ferromagnetic material such as steel, the magnetic flux emitted from the magnetic pole is absorbed by the base material, so that a sufficient magnetic flux density cannot be obtained in the molten pool, and the effects of the present invention cannot be obtained. There was also concern that it might be. However, as a result of the experiment, the magnetic flux leaks from the base metal part to the molten pool while the magnetic flux absorbed by the base metal from one magnetic pole is absorbed by the other magnetic pole. The magnetic flux can be secured, and the same effect was obtained in the ferromagnetic material as in the non-magnetic material. FIG. 8 shows the results of experiments conducted in an upward posture using carbon steel, which is a ferromagnetic material, and the flattening of the arc shape, the reduction of the penetration width, the control of the bead shape, and the like were similarly obtained. Yes. The welding conditions in FIG. 8 are substantially the same as in FIG.

The positional relationship between the magnetic pole and the welding electrode is the same as that in FIG. 1 even when the magnetic pole and the welding electrode are placed so as to face each other with the base material therebetween (when the coil and the magnetic pole are arranged on the lower side in FIG. 1). It is done.

The conceptual diagram which shows an example of the arc welding apparatus of this invention AA sectional view of FIG. Waveform diagram example of asymmetrical AC magnetizing current BB sectional view of FIG. Example of the form observed from the weld line direction (A) When no magnetic field is applied (B) When an asymmetrical alternating magnetic field is applied Photograph showing bead shape control and solidification crystal refinement effect (A) When no magnetic field is applied (B) When an asymmetrical alternating magnetic field is applied Photo showing stabilization effect of back bead (A) When no magnetic field is applied (B) When an asymmetrical alternating magnetic field is applied Photo showing bead shape control and bead width reduction effect (A) When no magnetic field is applied (B) When an asymmetrical alternating magnetic field is applied

Explanation of symbols

1: welding power source, 2: welding electrode, 3: power source for additive wire, 4: additive wire, 5: asymmetrical AC magnetizing power source, 6: magnetizing coil, 7: iron core, 7a: magnetic pole, 7b: magnetic pole (inverse of 7a) Polarity magnetic pole), 8: base material, 9: arc, 9A: foot part of arc when no magnetic field is applied, 9B: foot part of arc when AC magnetic field is applied, 10: molten pool, 11: wire feeding Device, 12: magnetic flux,
13Fu: Electromagnetic force for driving the molten metal upward, 14Fn: Electromagnetic force for driving the molten metal downward, 15: Wheel mechanism, 16Id: One-way current, 20Dr: Asymmetry rate of magnetizing current, 21: Positive electrode Current, 22: Current at negative electrode, 23Iav: DC component at time average, 24tp: Time at positive electrode, 25tn: Time at negative electrode, 26IDr: Asymmetrical AC magnetizing current, 30Fl: Electromagnetic force for driving the arc to the left, 31Fr: Electromagnetic force for driving the arc to the right, 40: Undercut defect, 41: Bond line of weld, 42A: Coarse columnar crystal, 42B: Refined columnar crystal, 50: Current-carrying tip

Claims (9)

In welding in a downward posture or an upward posture, an energy bundle is charged or irradiated to face the material to be welded to form a molten pool in the material to be welded, and a heating current is supplied to the molten pool through a wire added to the molten pool. energized, the peak value of the peak value of the time of the positive-side comprises a DC magnetic field component in the direction to intersect the parallel and weld line on the surface base material formed with the negative times and different or positive and negative is A welding method characterized by applying a magnetic field that varies as different asymmetrical alternating currents. In welding in a downward posture or an upward posture, an energy bundle is input to face the material to be welded to form a molten pool, and a heating current is passed through the molten pool via a wire added to the molten pool, and the molten metal is melted. together to form a strong current directionality in Ikeuchi, a magnetic field peak value of the peak value and the negative side of the times and different or positive side of the time and negative for positive includes a DC magnetic field component varies as different asymmetrical AC A welding method characterized in that an electromagnetic force is generated in the molten pool by applying in a direction substantially parallel to the surface of the material to be welded and intersecting the current or energy flux in the molten pool. The welding method according to claim 1, wherein the work piece and the magnetic pole are kept at a constant distance, and the weld pool and the magnetic pole are kept at a constant distance. The welding method according to any one of claims 1 to 3, wherein the flow of the molten metal is controlled by a unidirectional electromagnetic force generated by a DC component magnetic field. In flat position or upward position welding, the peak arc time a DC component in the direction of direction substantially perpendicular toward the base material of the unrealized positive and negative time and is different or peak value of the positive and negative arc welding method characterized by imparting a magnetic field whose value varies as different asymmetrical alternating current to vibrate and / or deflecting the arc welding line direction by an electromagnetic force. The arc welding method according to claim 5, wherein the arc is flattened so that the heat source is distributed long in the weld line direction on an average by electromagnetic force and narrowly distributed in a direction perpendicular to the weld line. Arc is applied a magnetic field peak value time and are different or peak value of the positive side and negative side of the positive side of the time and negative in a direction substantially perpendicular to the direction toward the workpieces varies as different asymmetrical AC, The arc welding method according to claim 1, wherein the arc and the molten metal are simultaneously driven by electromagnetic force. In arc welding equipment that forms a weld pool by generating an arc facing the work piece in the downward or upward position welding, the time on the positive side is different from the time on the negative side or the peak value on the positive side is negative. Magnetizing power source that fluctuates as an asymmetrical alternating current with different peak values and a counter magnetic pole in the vicinity of the molten pool, the positive side time and the negative side time are different, or the positive side peak value and the negative side peak value The positive time and negative time supplied from a magnetized power supply that fluctuates as different asymmetrical alternating currents or currents fluctuating as asymmetrical alternating currents in which the positive peak value and the negative peak value are different from the opposite magnetic pole. An arc welding apparatus characterized in that the magnetic flux generated from the arc is caused to act in a direction that intersects with the electric current flowing through the arc and / or the molten pool. In welding in a downward or upward posture, it has a discharge mechanism such as arc or corona discharge and / or a mechanism that directly energizes the vicinity of the molten pool, and irradiates the workpiece with a laser beam while supplying current to the molten pool. In a laser welding apparatus for forming a molten pool, the magnetizing power source and the melting which fluctuate as an asymmetrical alternating current in which a positive time and a negative time including a DC component are different or a positive peak value and a negative peak value are different near comprising opposing pole pond, time and the negative side of the positive times and different or positive positive side peak value of the peak value and the negative side is supplied from the magnetization power source that varies as different asymmetrical exchange the discharge or the magnetic flux generated from the said facing pole by a current that varies as the time are different or asymmetric AC peak value of the peak value and the negative side of the positive side is different in time and negative The laser welding apparatus is characterized in that so as to act in the direction to intersect the current serial molten pool.

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