JPH05261565A - Working method using electron beam - Google Patents

Abstract

PURPOSE:To provide a working method using electron beam without generating welding defect even in welding a member to be worked such as a material low in toughness or containing much gaseous component. CONSTITUTION:This is a method used for projecting then converging, deflecting an electron beam, irradiating the member to be worked with the electron beam and working the member to be worked. This method is used for melting part of the member to be worked by the electron beam and using the electron beam to stir the generated molten material. As a result, since the molten metal is stirred completely uniformly, impurities can be prevented from being concentrated at one position and since strains can be uniformized, no crack is generated at the time of welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method using an electron beam. More specifically, it relates to a processing method using an electron beam which can be suitably used for welding a cathode material made of tungsten or a crucible.

[0002]

2. Description of the Related Art Since the electron beam has a very high energy density, the electron beam welding method is characterized in that it is possible to perform high-speed welding of thin plates and deep penetration welding of thick plates by using an electron beam having this high energy density. Is. As the electron beam welding method, there is known an electron beam welding method in which an electron beam is oscillated at a high frequency in order to suppress welding defects, and pores are reduced by the swing effect of the molten pool.

First, a processing method by an electron beam welding method using a conventional electron beam processing apparatus will be described.

FIG. 6 shows a schematic structure of an electron beam processing apparatus described in “Micro Processing Technology” edited by the Micro Processing Technology Editorial Committee, November 27, 1981, Nikkan Kogyo Shimbun Co., Ltd., page 33. It is a schematic explanatory view. In FIG. 6, 1 is a housing, 2 is an electron gun disposed in the upper part of the housing 1, 3 is a focusing coil for focusing an electron beam 4 emitted from the electron gun 2, and 5 is a focusing coil. Power source, 6 is electron beam 4 focused by focusing coil 3
A deflection coil for deflecting the
Reference numeral 8 is a control signal generator for controlling the deflection coil power supply 7 to set the deflection pattern of the electron beam 4, and 9 is a workpiece to which the electron beam 4 is irradiated and butt welding is performed. It is placed in.

The conventional electron beam processing apparatus is constructed as described above, and the electron beam 4 emitted from the electron gun 2 at the time of processing using the apparatus has a desired size by the focusing coil 3. After being focused to a diameter, it is incident on the deflection coil 6. On the other hand, in the control signal generator 8, a control signal is sent to the deflection coil power source 7 by a predetermined deflection device. With this control signal, the deflection coil power supply 7 supplies a deflection current according to the control signal to the deflection coil 6, and the deflection coil 6 generates a deflection magnetic field according to this deflection current. Then, after the direction of the incident electron beam 4 is controlled by the deflection magnetic field, the member 9 to be processed is irradiated. On the other hand, the carriage 10 moves at a predetermined speed along the welding line, and welding proceeds.

FIG. 7 shows a carriage 10 in which an electron beam is circularly deflected.
3 is a diagram showing a trajectory of an electron beam on a member to be processed in a state where is not moving. Further, FIG. 8 is a trajectory of the electron beam on the workpiece when the carriage 10 is moved while circularly deflecting the electron beam.

[0007]

In the conventional welding by circular deflection shown in FIG. 7, when the carriage is moved in the direction indicated by the arrow A and is irradiated with the electron beam, the welding shown in FIG. 8 is performed. However, when welding a welding material with low toughness or a welded material containing many gas components, welding defects such as weld cracks, blowholes (blowouts), and blowouts (blowing out) are generated. However, there is a problem in that they cannot be prevented sufficiently.

The present invention has been made in order to solve the above-mentioned problems, and includes a welding material having a low toughness and easily cracked after welding and a large amount of gas components, and welding defects such as blowholes and blowouts due to welding. It is an object of the present invention to provide a processing method that does not cause the welding defect even when welding a welded member that easily causes

[0009]

SUMMARY OF THE INVENTION The present invention is a method for processing a member to be processed by emitting an electron beam, then focusing, deflecting and irradiating the member to be processed. The present invention relates to a processing method using an electron beam, which comprises melting a part of a member and stirring the generated melt.

[0010]

According to the processing method using the electron beam of the present invention, since a part of the member to be processed is melted and stirred by using the electron beam, the molten metal is uniformly stirred at a high speed. The gas components and low-melting-point impurities contained in are scattered, and the remaining impurities are dispersed at the time of melting so that the strain is cooled in a state where the strain is not concentrated at one place, and defects such as cracks are less likely to occur.

Further, according to the processing method of the present invention, since the molten pool is formed large, the cooling rate becomes slower, and defects such as cracks are more difficult to occur.

Further, in the present invention, particularly when an electron beam deflected into a spiral irradiation pattern is used, a beat is generated by the spiral irradiation pattern, which causes a large vibration. Further, the scattering and dispersion of impurities and the effect of expanding the molten pool are further promoted, and defects such as cracks are less likely to occur.

[0013]

EXAMPLE As described above, the processing method using an electron beam of the present invention is a method of processing a member to be processed by injecting the electron beam, then focusing, deflecting and irradiating the member to be processed. Accordingly, the processing method using an electron beam is characterized in that a part of the member to be processed is melted by the electron beam and the generated melt is stirred.

In the present invention, working a member to be worked means, for example, welding a member to be worked such as metal, melting the surface layer of the member to be worked and hardening the surface.

In the processing method of the present invention, when processing is performed, an electron beam is first emitted by an electron gun. The electron gun used may be one that is normally used for welding a workpiece such as metal, and the wavelength of the emitted electron beam may be any one that is also commonly used. For example, the energy conversion of 60 KeV is, for example, about 2.1 × 10 ^-11 m.

Next, the electron beam is focused by a focusing coil so that the electron beam has a desired focusing diameter when it is applied to the workpiece. The focusing diameter is usually 0.2-0.3 mmφ
It is preferably about the same.

Next, the electron beam after passing through the focusing coil is deflected by the deflection coil so as to have a specific irradiation pattern described later. Since the deflection coil is controlled by the control signal generator, the control signal generator determines the irradiation pattern of the electron beam to the member to be processed, and controls so that the deflection is performed in accordance with the determined irradiation pattern. Generate a signal. Next, in the deflection coil power supply, a current based on the control signal is applied to generate a deflection magnetic field in the deflection coil, and the workpiece to be processed using the electron beam deflected by the deflection magnetic field is processed, for example, by welding. Apply.

The present invention has one feature in the irradiation method of the electron beam deflected by the deflection coil. That is, in the present invention, a part of the member to be processed is melted by using an electron beam, and the generated melt is evenly stirred. The method is not particularly limited, but it is effective to irradiate the member to be processed with an electron beam deflected into a spiral irradiation pattern, for example. The spiral irradiation pattern refers to the trajectory of the electron beam as shown in FIG. 1 when the dolly is stationary. Here, when the distance from the center O of the spiral wire to the outer circumference is D and the difference from the distance when the spiral wire makes one round is the pitch d, the pitch d is set to be smaller than the electron beam focusing diameter. For example, it is preferably about 50 to 100 μm, and D is preferably about 1 to 1.5 mm.

Since the dolly on which the member to be processed is placed moves during the irradiation of the electron beam, the actual trajectory of the electron beam on the member to be processed is as shown in FIG.

When the pitch d is made smaller than the focusing diameter of the electron beam, the actual irradiation pattern is different from that shown in FIG. 1 because the inside of the spiral irradiation pattern is completely filled. The processed part is evenly melted and stirred. In addition, the spiral pattern causes a beat, which causes a large vibration in the molten metal. The scanning speed of electron beam is 1000m / min or more, especially 1000-2000m from the viewpoint of the smoothness of the surface bead after melting and stirring.
/ Min is preferred. The irradiation of the electron beam is continuously carried out, and when the irradiated spiral locus approaches the central portion and reaches a certain point, it returns to the first point again, and the same irradiation pattern is repeated.

On the other hand, the member to be processed is placed on the carriage and moves along the welding line. The moving speed of the trolley is not particularly limited, but in the case of welding a material with high melting point and small toughness that is easily cracked, by setting the welding speed low, the same effect as preheating and postheating can be obtained. Therefore, the welding speed is preferably about 0.05 to 0.1 m / min.

Examples of the member to be processed include metals having a high melting point and low toughness such as tungsten and molybdenum. When the member to be processed is irradiated with an electron beam, high heat is generated, the metal surface begins to melt and a large molten pool is formed. It becomes difficult for such defects to occur. Further, as described above, when the spiral irradiation pattern is used, the molten metal is evenly stirred and a beat occurs, which causes a large vibration in the molten metal and is included in the molten metal. The gas components and low-melting-point impurities such as phosphorus and sulfur are scattered, and the remaining impurities are dispersed without concentrating at the freezing point, so that defects such as cracks are less likely to occur.

Although the method of welding the member to be processed by the spiral irradiation pattern has been described above, in the present invention, the X-shaped irradiation pattern shown in FIG. 4 is used instead of the spiral irradiation pattern.
The workpiece may be welded by using a surface deflection pattern that becomes a net-like irradiation pattern within a fixed rectangular plane on the axis and the Y axis.

In this case, the size of the rectangle is not particularly limited, but is preferably, for example, about 1 to 1.5 mm in length and 1 to 1.5 mm in width. It is preferable that each is about 0.05 to 0.1 mm in order to stir carefully. The wavelength and the focusing diameter of the electron beam used for the irradiation may be the same as those for the irradiation of the spiral beam. The mesh pattern is the X of the deflection coil.
It is formed by flowing deflection signals having a triangular wave and different phases on the axis and the Y axis. In the case of a square shape, the maximum value of the triangular wave may be made equal on the X axis and the Y axis.

The scanning speed of the electron beam is 500 m /
It is preferably at least about 1000 to 2000 m / min. Irradiation with electron beam is continuously performed,
The irradiation pattern shown in FIG. 4 is continuously repeated. On the other hand, the member to be processed placed on the trolley moves along the welding line, and processing such as welding is performed. At this time, the moving speed of the trolley is set to a low speed of 0.05 m / min. It is preferably about a minute.

Examples of the member to be processed include the same metals as described above, and the same effect as when the member to be processed is heated by irradiation of an electron beam and is irradiated in a spiral shape is obtained.

In the processing method using the electron beam of the present invention, quenching can be performed in addition to welding.
The equipment and irradiation pattern used in this case are the same as in welding, but the scanning speed of the electron beam should be faster than in welding and the focusing diameter of the electron beam should be large. Therefore, it is preferable to reduce the amount of heat generated per unit area so that melting does not occur on the surface or inside of the member to be processed.

In the above quenching, since the beam irradiation pattern can be arbitrarily selected, the quenching can be performed at a power density that does not cause melting depending on the heat capacity of the quenching work.

Next, the processing method of the present invention will be described in detail based on examples, but the present invention is not limited to these examples.

[Embodiment 1] As an electron beam processing apparatus,
An apparatus having an electron gun, a focusing coil power source, a focusing coil, a control signal generator, a deflection coil power source and a deflection coil (manufactured by Mitsubishi Electric Corp., 60 KeV, 6 KW) was used.

In this embodiment, the wavelength of the emitted electron beam is set to 2.1 × 10 ^-11 m, and the focusing diameter on the workpiece to be focused by the focusing coil is 0.2 mmφ.

As the irradiation pattern, a spiral pattern in which the distance D from the center of the spiral wire to the outer circumference shown in FIG. 1 is 1.4 mm is adopted, and it is the difference in distance when the spiral wire makes one revolution. The pitch d is 0.1 mm.

The scanning speed of the electron beam is 1000 m / min,
The trajectory of the spiral to be irradiated approaches the central part and is set to return to the first point again when it reaches the point of 0.1 mm below the size of the beam diameter from the center, and by repeating the irradiation pattern continuously. Irradiation with an electron beam was performed.

In this embodiment, when two flat plates made of tungsten are butted against each other and the welding is performed, the welding member is placed on the carriage and the carriage moves at a speed of 0.05 m / min, whereby a welding line is formed. Welded along

The metal structure of the surface bead of the tungsten material thus obtained is shown in FIG. 3. As can be seen from the figure, the surface bead did not crack at all and the surface bead was smooth.

[Embodiment 2] An apparatus similar to that of Embodiment 1 is used and a plane deflection pattern is used as shown in FIG. 4 in which a plane of a fixed rectangle on the X-axis and the Y-axis becomes a net-like irradiation pattern. In the same manner as in Example 1, two flat plates made of tungsten were butt-welded together.

In this case, the size of the rectangle is 1.4 mm in length and horizontal.
It was 1.4 mm, and x and y in the figure were about 0.05 mm. The wavelength and the focusing diameter of the electron beam used for the irradiation were the same as in Example 1.

The scanning speed of the electron beam is 0.05 m /
The irradiation with the electron beam was performed by continuously repeating the irradiation pattern shown in FIG.

In this embodiment, two tungsten flat plates were welded to each other.

When welding is performed, the member to be processed is placed on a dolly, and the dolly is set to perform welding along the welding line by moving at a speed of 0.05 m / min. ..

The metal structure of the surface bead of the butt joint thus obtained is shown in FIG. 5. As can be seen from the figure, the surface bead did not crack at all and the surface bead was smooth.

[Comparative Example 1] Using the same apparatus as in Example 1, the butt welding of the tungsten plates was carried out in the circular deflection pattern as shown in FIG.

In this case, the diameter of the circle was 1.4 mm, and the wavelength of the electron beam and the focusing diameter were set in the same manner as in Example 1.
Further, the scanning speed of the electron beam was set to 1000 m / min.

In this comparative example, the flat plates of tungsten plates were welded together by butt welding. When welding
The welding member was placed on a carriage, and the carriage moved at a speed of 0.05 m / min so that welding was performed along the welding line.

The metal structure of the surface beat of the tungsten plate thus obtained is shown in FIG. 9. As can be seen from the figure, cracking of the surface bead was observed.

[0046]

According to the processing method using the electron beam of the present invention, it is possible to perform welding without the occurrence of welding defects such as cracks.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an electron beam irradiation pattern in a processing method using an electron beam of the present invention.

FIG. 2 is an explanatory diagram of an irradiation pattern of a member to be processed which is irradiated with an electron beam in the processing method using the electron beam of the present invention.

FIG. 3 is a photograph of a metal structure of a surface bead processed by the processing method using an electron beam of the present invention.

FIG. 4 is an explanatory diagram of an electron beam irradiation pattern in a processing method using the electron beam of the present invention.

FIG. 5 is a photograph of a metal structure of a surface bead processed by the processing method using an electron beam of the present invention.

FIG. 6 is an explanatory diagram of a conventional electron beam processing apparatus.

FIG. 7 shows a conventional processing method using an electron beam,
It is explanatory drawing of the irradiation pattern of an electron beam.

FIG. 8 shows a conventional processing method using an electron beam,
It is explanatory drawing of the irradiation pattern of the to-be-processed member irradiated with the electron beam.

FIG. 9 is a photograph of a metal structure of a surface bead processed by a processing method using an electron beam of Comparative Example 1.

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[Procedure amendment]

[Submission date] August 6, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction content]

The scanning speed of the electron beam is 500 m /
The irradiation with the electron beam was performed by continuously repeating the irradiation pattern shown in FIG.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

FIG. 4 is an explanatory diagram of an electron beam irradiation pattern in the processing method using the electron beam of the present invention.

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

Claims (1)

[Claims] 1. A method for processing a member to be processed by emitting an electron beam, converging, deflecting and irradiating the member to be processed, wherein a part of the member to be processed is melted by an electron beam, A processing method using an electron beam, which comprises stirring the generated melt.