JP6843512B2 - Electron beam welding equipment, computer programs, electron beam welding methods - Google Patents

Description

The present invention relates to an electron beam welding apparatus, a computer program, and an electron beam welding method.

For example, as disclosed in Patent Document 1, in electron beam welding, the workpieces on both sides of the groove are melted by irradiating the groove where the workpieces (work objects) are butted against each other with an electron beam. To join. After being emitted from the electron gun, the electron beam is focused by the electromagnetic field generated by the focus coil, so that the electron beam is irradiated to the groove portion in a state where the energy density is increased.

Here, the electron beam welding can be performed in a so-called one pass, in which welding is performed only once along the groove portion while irradiating the electron beam. On the other hand, if the work is melted by irradiation with an electron beam and then the melted work is cooled and solidified, the strength is lowered due to the influence of the heat input of the electron beam.

Japanese Unexamined Patent Publication No. 2014-24089

For example, when electron beam welding is performed on a thick plate of 50 mm or more, it is necessary to melt the workpieces on both sides of the groove portion in the entire plate thickness direction of the thick plate in order to perform reliable welding. For this purpose, it is necessary to increase the amount of heat input by the electron beam to the thick plate. However, as a result of increasing the amount of heat input, the degree of deterioration of mechanical properties such as strength and toughness of the welded portion due to the influence of heat input of the electron beam becomes large.
Therefore, an object of the present invention is an electron beam welding apparatus and a computer program capable of reliably performing welding even on a thick plate, suppressing the amount of heat input, and improving mechanical properties such as strength and toughness of the welded portion. , To provide an electron beam welding method.

The present invention employs the following means in order to solve the above problems.
The electron beam welding apparatus according to one aspect of the present invention includes an electron gun that irradiates an electron beam toward a groove portion of a pair of workpieces that are butted against each other, a focus coil that focuses the electron beam by an electric current, and a focus coil. A control unit that changes the current value supplied to the focus coil while irradiating the electron beam along the groove portion to change the focal position of the electron beam in the plate thickness direction of the workpiece. When, wherein the control unit, during the predetermined time Ts, a plurality of pulses of different current waveform peak position of the current value by supplying to the focus coil, the focal position is the plate thickness direction Different electron beams are sequentially generated, and the plurality of pulses include a first pulse having the focal position on the front surface side of the workpiece, a second pulse having the focal position in the central portion in the plate thickness direction, and a back surface. It includes at least a third pulse having the focal position on the side .

According to such a configuration, while irradiating the electron beam along the groove portion, the current value supplied to the focus coil is changed to change the focal position of the electron beam in the plate thickness direction of the workpiece. I tried to make it. As a result, welding by the electron beam can be reliably performed over the entire plate thickness direction of the groove portion.
Further, in this way, when the current is supplied with the current waveforms of a plurality of pulses in which the peak positions of the current values are different from each other in the plate thickness direction for a certain period of time, the focal position of the electron beam can be easily set in the plate thickness direction of the workpiece. Can be varied to.

The computer program according to one aspect of the present invention is a computer program executed by a control unit of an electron beam welding apparatus, and irradiates an electron beam from an electron gun toward a groove portion of a pair of workpieces butted against each other. And the focus coil that focuses the electron beam by an electric current so that the focal position of the electron beam changes in the plate thickness direction of the object to be processed while irradiating the electron beam. a step of varying a current value, during a predetermined time Ts, by providing multiple pulses of peak positions mutually different current waveform of the current value to the focus coil, the said focal positions are different in the thickness direction The plurality of pulses include a step of sequentially generating an electron beam, the first pulse having the focal position on the surface side of the object to be processed, and the second pulse having the focal position in the central portion in the plate thickness direction. It is characterized by including at least a third pulse having the focal position on the back surface side .

The electron beam welding method according to one aspect of the present invention is an electron beam welding method executed by an electron beam welding apparatus, and is a step of irradiating an electron beam toward a groove portion of a pair of workpieces butted against each other. The current value supplied to the focus coil that focuses the electron beam by an electromagnetic field so that the focal position of the electron beam changes in the plate thickness direction of the object to be processed while irradiating the electron beam. a step of varying the, during the predetermined time Ts, by providing multiple pulses of peak positions mutually different current waveform of the current value to the focus coil, the electron beam the focal positions are different in the thickness direction The plurality of pulses include a first pulse having the focal position on the surface side of the workpiece, a second pulse having the focal position in the central portion in the plate thickness direction, and the like. It is characterized by including at least a third pulse having the focal position on the back surface side .
With such a configuration, welding by the electron beam can be reliably performed over the entire plate thickness direction of the groove portion.

The electron beam welding method according to one aspect of the present invention includes, in the electron beam welding method, a step of irradiating the electron beam so as to include the groove portion to form a primary welding bead, and at least the primary welding bead. The step includes a step of forming a secondary weld bead in which at least one of the positions and widths in a direction orthogonal to the continuous direction of the groove portion is different from that of the primary weld bead.
According to such a configuration, by overlapping the primary welding bead and the secondary welding bead, the width of the welding bead formed at the groove can be widened, defects due to misalignment can be prevented, and the weld metal can be prevented. It is possible to prevent a decrease in the strength of the.

According to the electron beam welding apparatus, computer program, and electron beam welding method according to the present invention, even a thick plate is reliably welded, the amount of heat input is suppressed, and mechanical properties such as strength and toughness of the welded portion are improved. Can be made to.

It is a figure which shows the schematic structure of the electron beam welding apparatus which concerns on embodiment of this invention. It is a figure which shows the flow of the process of the electron beam welding method which concerns on embodiment of this invention. It is a figure which shows the example of the current waveform of a plurality of pulses, and the example of the composite waveform of the current waveform of these a plurality of pulses which are generated sequentially from a control part in a fixed time. An example of the energy distribution of the electron beam when a current is supplied to the focus coil with the current waveform as shown in FIG. 3 is shown. It is a figure which shows an example of the current waveform when the peak position of the current in a plate thickness direction remains fixed in a plurality of pulses sequentially generated from a control unit in a fixed time, and the composite waveform thereof. An example of the energy distribution of the electron beam when a current is supplied to the focus coil with the current waveform as shown in FIG. 5 is shown. It is a figure which shows the comparison between the heat input distribution to the groove part when the focal position of an electron beam is fixed, and the heat input amount distribution to a groove part when the focal position of an electron beam is changed. It is a figure which shows the modification of the electron beam welding method which concerns on embodiment of this invention. It is a figure which shows the other modification of the electron beam welding method which concerns on embodiment of this invention.

Hereinafter, embodiments for carrying out the electron beam welding apparatus, computer program, and electron beam welding method according to the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to this embodiment.

FIG. 1 is a diagram showing a schematic configuration of an electron beam welding apparatus 10 according to the present embodiment.
As shown in FIG. 1, the electron beam welding device 10 includes an electron gun 11, a focus coil 12, a work holding unit (not shown), and a control unit 20.

The electron gun 11 emits electrons from the cathode 11a as an electron beam EB with an energy density corresponding to a current supplied from a power source (not shown).

The focus coil 12 and the work holding portion (not shown) are provided in a vacuum chamber (not shown). In this embodiment, the focus coil 12 is provided in two stages of the first focus coil 12A and the second focus coil 12B in the radiation direction of the electron beam EB. The first focus coil 12A and the second focus coil 12B generate an electromagnetic field according to a current supplied from a power source (not shown), and focus the electron beam EB emitted from the electron gun 11.

The work holding portion (not shown) holds the workpieces (workpieces) 100, 100 to be welded in a state of being butted against each other. The work holding portion (not shown) is in a plane orthogonal to the radiation direction of the electron beam EB, and at least in a direction in which the groove portions 100k in which the workpieces 100 and 100 are butted against each other are continuous (orthogonal to the paper surface in FIG. 1). The held workpieces 100 and 100 can be moved relative to the electron gun 11 along the direction).
In this embodiment, the workpieces 100 and 100 may be low alloy steel, austenitic stainless steel, or the like.

The control unit 20 controls the current supply to the electron gun 11, the first focus coil 12A, and the second focus coil 12B, and the movement of the work holding unit (not shown).

Hereinafter, the flow of the electron beam welding method in the electron beam welding apparatus according to the present embodiment will be described.
FIG. 2 is a diagram showing a processing flow of the electron beam welding method according to the present embodiment.
The control unit 20 realizes an electron beam welding method as shown below by sequentially executing predetermined processes based on a computer program installed in advance.
As shown in FIG. 2, when the electron beam welding process is started, the control unit 20 radiates the electron beam EB from the electron gun 11 and irradiates the groove portions 100k of the workpieces 100 and 100 (step S101). At the same time, the work holding portion (not shown) moves the held workpieces 100, 100 along the direction in which the groove portion 100k is continuous with respect to the electron gun 11. As a result, the electron beam EB irradiating the groove portion 100k from the electron gun 11 melts the workpieces 100 and 100 on both sides of the groove portion 100k by the beam, and welding along the groove portion 100k is sequentially performed. ..

While the control unit 20 irradiates the electron beam EB along the groove portion 100k as described above, the control unit 20 changes the current applied to the second focus coil 12B in the following manner to change the current applied to the second focus coil 12B of the electron beam EB. The focal position is changed (step S102). Here, as shown in FIG. 1, in the second focus coil 12B, the intensity of the generated electromagnetic field changes depending on the applied current value, and the focal position F of the electron beam EB is the work 100, 100 at the groove portion 100k. It changes in the plate thickness direction T of.

FIG. 3 is a diagram showing an example of a plurality of pulsed current waveforms sequentially generated from the control unit during a certain period of time, and an example of a composite waveform of these plurality of pulsed current waveforms.
During a certain period of time Ts in which the electron beam EB is irradiated along the groove portion 100k, the control unit 20 uses a function generator (not shown) or the like to generate currents of a plurality of pulses having different current waveforms, and the second focus. It is supplied to the coil 12B. For example, as shown in FIG. 3, the control unit 20 supplies a current with a current waveform having a peak Pt1 on the surface 100f (see FIG. 1) side of the work 100 in the first pulse P1. Further, in the second pulse P2, a current is supplied with a current waveform having a peak Pt2 in the central portion in the plate thickness direction of the work. In the third pulse P3, a current is supplied with a current waveform having a peak Pt3 on the back surface 100 g (see FIG. 1) side of the work 100. The first pulse P1, the second pulse P2, and the third pulse P3 are sequentially supplied during a certain period of time Ts.
In this way, during a certain period of time Ts, the first pulse P1, the second pulse P2, and the third pulse P3 are generated while changing the peaks Pt1 to Pt3 of the current value in the plate thickness direction T (see FIG. 1) of the work 100. When output, the combined waveform W1 of the first pulse P1, the second pulse P2, and the third pulse P3 within the time Ts becomes a rectangular (trapezoidal) pulse shape in which the current value is substantially constant in the plate thickness direction T.

In this way, during a certain period of time Ts, in the first pulse P1, the second pulse P2, and the third pulse P3, the peaks Pt1 to Pt3 of the current value are changed in the plate thickness direction T of the work 100, and the groove portion is formed. The electron beam EB is irradiated along 100 k.
When the positions of the peaks Pt1 to Pt3 of the current value are shifted in the first pulse P1, the second pulse P2, and the third pulse P3, the focal position F of the electron beam EB emitted from the electron gun 11 sequentially moves in the plate thickness direction T. Change. That is, while irradiating the electron beam EB along the groove portion 100k, the focal position F of the irradiating electron beam EB can be changed in the plate thickness direction T of the work.

FIG. 4 shows an example of the energy distribution of the electron beam when a current is supplied to the focus coil with the current waveform as shown in FIG. In FIG. 4, the plate thickness direction is T, the direction X orthogonal to the plate thickness direction T is the width direction of the groove portion, and the direction Z orthogonal to the plate thickness direction T and the width direction X is the magnitude of energy.
When a current is supplied to the second focus coil 12B with a current waveform as shown in FIG. 3, as shown in FIG. 4, the energy distribution of the electron beam EB irradiated to the groove portion 100k is the energy distribution of the groove portion 100k. The size is almost constant in the plate thickness direction T. Therefore, the works 100 and 100 can be uniformly heated in the plate thickness direction T over the entire groove portion 100k.

For comparison, FIG. 5 shows the current waveforms when the peak positions of the currents in the plate thickness direction are kept fixed in a plurality of pulses sequentially generated from the control unit during a certain period of time, and their composite waveforms. It is a figure which shows an example.
As shown in FIG. 5, assuming that the peak position Pt0 of the current remains fixed in the first pulse P1', the second pulse P2', and the third pulse P3' that are sequentially generated during a certain period of time Ts, these second pulses In the combined waveform W0 of the one pulse P1', the second pulse P2', and the third pulse P3', the peak Pw of the current value becomes large in the central portion of the groove portion 100k in the plate thickness direction T.

FIG. 6 shows an example of the energy distribution of the electron beam when a current is supplied to the focus coil with the current waveform as shown in FIG.
As shown in FIG. 5, when the current is continuously applied to the second focus coil 12B while the current peak position Pt0 is fixed for a certain period of time Ts, the groove portion 100k is irradiated as shown in FIG. The energy distribution of the electron beam EB in the plate thickness direction T has the largest energy value at the peak position of the current in the current waveform (the central portion in the plate thickness direction T). That is, the amount of heat input to the central portion of the plate thickness direction T is large, and the amount of heat input to both sides of the plate thickness direction T is lower than that of the central portion of the plate thickness direction T.

FIG. 7 shows a comparison between the heat input distribution to the groove when the focal position of the electron beam is fixed and the heat input distribution to the groove when the focal position of the electron beam is changed. It is a figure.
As shown in FIG. 7, when welding is performed with the current peak position Pt0 in the plate thickness direction T fixed, that is, without changing the focal position of the electron beam EB in the plate thickness direction T, the plate thickness direction T In the central portion (cross section BB in FIGS. 6 and 7), the welding width (bead width) formed by the heat input by the electron beam EB is narrow, but the energy is concentrated and the heat input amount is large. Further, in this case, at the end portion in the plate thickness direction T (cross section AA in FIGS. 6 and 7), the offset dimension from the focal position of the electron beam EB is large with respect to the central portion in the plate thickness direction T. , The beam diameter of the electron beam EB is large. Therefore, the welding width is large and the amount of heat input is smaller than that of the central portion in the plate thickness direction T.

On the other hand, when welding is performed while changing the focal position of the electron beam EB in the plate thickness direction T, heat is uniformly applied in a wide range in the plate thickness direction T as described above. As a result, as shown in the cross sections CC in FIGS. 6 and 7, the welding width is smaller than the cross section AA when the focal position of the electron beam is fixed, and the amount of heat input is the focal point of the electron beam. It is smaller than the cross section BB when the position is fixed.

In this way, even when the plate thicknesses of the workpieces 100 and 100 are large, uniform heat input can be performed in the plate thickness direction T of the groove portion 100k, and welding can be performed uniformly. Further, this makes it possible to perform electron beam welding over the entire plate thickness direction T of the groove portion 100k with less energy.

According to the electron beam welding apparatus 10, the computer program, and the electron beam welding method as described above, the current value supplied to the second focus coil 12B is changed while the electron beam EB is irradiated along the groove 100k. The focal position of the electron beam EB was changed in the plate thickness direction of the work 100. As a result, welding by the electron beam EB can be reliably performed over the entire plate thickness direction T of the groove portion 100k. Therefore, even if the work 100 is a thick plate, it is possible to suppress the amount of heat input while reliably performing welding, and to improve mechanical properties such as strength and toughness of the welded portion.

Further, when the control unit 20 supplies a current with current waveforms of the first to third pulses P1 to P3 in which the peak positions of the current values are different from each other in the plate thickness direction T during a certain period of time Ts, the electron beam EB The focal position F can be easily changed in the plate thickness direction of the work 100.

(Modified example of the embodiment)
In the above embodiment, the case where the groove portion 100k is welded in one pass is shown, but the present invention is not limited to this. Electron beam welding may be performed on the groove portion 100k in a plurality of passes.
For example, as shown in FIG. 8, in the first pass of electron beam welding, a primary welding bead B1 having a large bead width is formed in a range including the groove portion 100k, and then in the second pass of electron beam welding, the bead width is increased. A smaller secondary weld bead B2 may be applied over the primary weld bead B1 and the groove portion 100k.

By forming the primary welded bead B1 having a large bead width in this way, it is possible to prevent the electron beam EB from losing its eyes from the groove portion 100k.

Further, as shown in FIG. 9, after forming the primary welding bead B4 having a constant width including the groove portion 100k by the first pass electron beam welding, the groove portion 100k is formed by the second pass electron beam welding. On the other hand, the secondary welding bead B5 may be formed on one side in the width direction, and the secondary welding bead B6 may be formed on the other side in the width direction with respect to the groove portion 100k by the third pass electron beam welding. Further, the secondary welding bead B7 may be applied to the portion including the groove portion 100k so as to overlap the primary welding bead B4, the secondary welding bead B5, and B6.

By performing the electron beam welding a plurality of times in this way, the strength and toughness decreased by the heat input of the electron beam welding can be improved by the so-called quenching effect, and the decrease in the strength of the weld metal can be prevented.

(Other embodiments)
The configuration of the electron beam welding apparatus 10 of the present invention is not limited to the above-described embodiment described with reference to the drawings, and various modifications can be considered within the technical scope thereof.
For example, in the above embodiment, an example in which a current is supplied by the first pulse P1, the second pulse P2, and the third pulse P3 during a certain period of time Ts is given, but during the time Ts, at finer time Ts intervals. The current may be supplied with more pulses.

Further, in the above embodiment, the focus coil 12 is provided with the first focus coil 12A and the second focus coil 12B, but the present invention is not limited to this. The focus coil 12 may be provided in only one stage or in three or more stages.

In addition to this, configurations other than the above may be adopted for the configuration of the electron beam welding apparatus 10, the detailed procedure of the electron beam welding method, and the like.

Further, each process of performing electron beam welding in the control unit 20 is stored in a computer-readable recording medium in the form of a computer program. The above processing is performed by reading and executing this computer program by a computer constituting the control unit 20. Here, the computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. This computer program may be distributed to a computer via a communication line, and the computer receiving the distribution may execute the program.
In addition to this, as long as the gist of the present invention is not deviated, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.

10 Electron beam welding device 11 Electron gun 11a Cathode 12 Focus coil 12A First focus coil 12B Second focus coil 20 Control unit 100 Work (workpiece)
100k Grooves B1, B3 Primary welding beads B2, B4, B5, B6, B7 Secondary welding beads EB Electron beam F Focus position P1 First pulse P2 Second pulse P3 Third pulse Ts Fixed time T Plate thickness direction W0 synthesis Waveform W1 composite waveform

Claims (4)

An electron gun that irradiates an electron beam toward the groove of a pair of workpieces that are butted against each other.
A focus coil that focuses the electron beam by an electromagnetic field,
A control unit that changes the current value supplied to the focus coil while irradiating the electron beam along the groove portion to change the focal position of the electron beam in the plate thickness direction of the workpiece. When,
With
Wherein, during the predetermined time Ts, by providing multiple pulses of peak positions mutually different current waveform of the current value to the focus coil, the electron beam the focal positions are different in the thickness direction Generate sequentially ,
The plurality of pulses include a first pulse having the focal position on the front surface side of the workpiece, a second pulse having the focal position in the central portion in the plate thickness direction, and a third pulse having the focal position on the back surface side. An electron beam welder that includes at least a pulse. A computer program executed by the control unit of an electron beam welder.
A step of irradiating an electron beam from an electron gun toward the groove of a pair of workpieces that are butted against each other,
While irradiating the electron beam, the current value supplied to the focus coil that focuses the electron beam is changed by an electromagnetic field so that the focal position of the electron beam changes in the plate thickness direction of the object to be processed. Steps to make and
During the predetermined time Ts, by providing multiple pulses of peak positions mutually different current waveform of the current value to the focus coil, the steps of the focal position is sequentially generating different said electron beam to said plate thickness direction ,
Equipped with a,
The plurality of pulses include a first pulse having the focal position on the front surface side of the object to be processed, a second pulse having the focal position in the central portion in the plate thickness direction, and a third pulse having the focal position on the back surface side. A computer program characterized by containing at least a pulse. An electron beam welding method performed by an electron beam welding device.
A process of irradiating an electron beam toward the groove of a pair of workpieces that are butted against each other,
While irradiating the electron beam, the current value supplied to the focus coil that focuses the electron beam is changed by an electromagnetic field so that the focal position of the electron beam changes in the plate thickness direction of the object to be processed. And the process of making
During the predetermined time Ts, by providing multiple pulses of peak positions mutually different current waveform of the current value to the focus coil, a step of the focal position is sequentially generating different said electron beam to said plate thickness direction ,
Equipped with a,
The plurality of pulses include a first pulse having the focal position on the front surface side of the workpiece, a second pulse having the focal position in the central portion in the plate thickness direction, and a third pulse having the focal position on the back surface side. An electron beam welding method comprising, at least, a pulse. A step of irradiating the electron beam so as to include the groove portion to form a primary welding bead, and
A step of forming a secondary weld bead that overlaps at least a part of the primary weld bead and has a different position and width from the primary weld bead in a direction orthogonal to the continuous direction.
The electron beam welding method according to claim 3.

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