JP2005081402A - Welding method by high energy density beam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable welding by expanding the deviation tolerance of a beam target position in emitting a high energy density beam from the back of the abutting part of the members to be welded, forming a back bead sufficient for the abutting part, thereby relaxing the stress concentration of the abutting part and preventing a corrosive gas or liquid from infiltrating into the weld zone. <P>SOLUTION: In the welding method, an abutting part is welded by emitting a high energy density beam from the back of the abutting part between members 1, 2 to be welded. With particle substance 5 filled in the space S which is formed by the members to be welded constituting the abutting part, the high energy density beam is emitted from the back of the abutting part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a high energy density suitable for manufacturing impellers used in air compressors, pumps, and the like that perform irradiation of a high energy density beam by irradiating a high energy density beam from the back of a butt portion between welded members. The present invention relates to a welding method using a beam.

  As a method of manufacturing a structure having a space between a shroud such as an impeller used in an air compressor or a pump and a disk, a narrow gap portion is removed by integral manufacturing by precision casting or electric discharge machining. In the manufacturing method such as the method of performing diffusion bonding or the method of diffusion bonding, there are many problems such as a rough surface, high cost, and a lot of time required, and therefore assembly by welding is common.

  As an assembly by welding, there is a high energy density beam welding using an electron beam or a laser beam using a carbon dioxide gas, a YAG crystal, a semiconductor or the like as an oscillation source, and this welding has an advantage that a deep penetration can be obtained. .

  Further, the impeller is a rotating body, and as the rotational speed increases, a large stress in which centrifugal stress and vibration stress are superimposed on the root portion of the blade. For this reason, it is necessary to reduce the stress concentration by forming the weld toe shape into a smooth R shape.

  In manufacturing an impeller by high energy density beam welding, when a blade and a shroud or a disk are joined, the shroud and the blade are still welded by an electron beam. For this reason, a blade root part becomes a stress concentration part, and there exists a possibility that a crack may generate | occur | produce from a blade root part. Since the root portion of the shroud and the blade is a portion to which high stress is applied, a large curvature (R portion) is required to alleviate stress concentration. However, in order to form a large curvature (R portion), significant cutting is required. In particular, it is very difficult to perform cutting on a curved and complicated welded portion such as an impeller, which leads to an increase in cost.

  In welding with a high energy density beam, very high accuracy is required to adjust the target position of the beam aim. However, if deformation occurs in the welding object due to the occurrence of thermal distortion due to welding heat input, the beam aiming position shifts, and the blade part melts down or the shroud is blown out.

  Furthermore, since the impeller can be used in a corrosive environment such as hydrogen sulfide, carbon dioxide gas, and high temperature and humidity, if there is a gap between the blade root portion and the shroud or the joint of the disk, the portion is easily corroded. . Accordingly, it is required that there is no gap at the joint between the blade root portion and the shroud or the disk.

  There are the following patent documents showing conventional welding methods using an electron beam.

JP 2002-98090 A

  In the welding method of the said patent document, it fills with the heat-resistant substance in the space which members to be welded form, and it proposes removing the substance after welding.

  According to the welding method of the above-mentioned patent document, since the heat-resistant substance prevents the melt-down, it is not necessary to perform cutting even in a curved and complicated welded place like an impeller, and the shroud There is no fear of fusing, and there is no risk of corrosion because there is no gap in the joint.

  However, this material is processed in advance so as to form a space formed by the members to be welded, and if the space has a complicated shape, it becomes difficult to process the material. And it is difficult to remove a material having a shape unique to the space after welding.

  Therefore, the object of the present invention is to increase the beam misalignment tolerance when irradiating a high energy density beam from the back of the butt portion between the welded members, and to the butt portion between the welded members. A sufficient back wave bead can be formed, thereby reducing the stress concentration at the butt and preventing the entry of corrosive gas and liquid into the joint, and providing a reliable welding method using a high energy density beam There is to do.

  The present invention that achieves the above object is characterized in that in the welding method using a high energy density beam, a high energy density beam is irradiated by irradiating a high energy density beam from a back surface of a butt portion between welded members. The space formed by the members to be welded constituting the portion is filled with a granular material, and a high energy density beam is irradiated from the back surface of the butt portion.

  According to the welding method of the present invention, the molten metal of the members to be welded by the high energy density beam is suppressed from being melted by the granular substance that can be easily filled in the space formed by the members to be welded. The tolerance of misalignment of the target position of the beam when irradiating a high energy density beam from the back of the butt part can be expanded, and a sufficient back wave bead can be formed at the butt part between the welded members. Reducing stress concentration at the butt and preventing the ingress of corrosive gas and liquid into the joint, resulting in highly reliable welding. In addition, the particulate matter can be easily removed after welding.

  In the following, an embodiment of the present invention will be described by taking as an example the joining of a blade and a disk integrated in advance and a shroud shown in FIG.

  In FIG. 2, 1 is a shroud, 2 is a blade, 3 is a disk, the shroud 1 and the disk 3 are cross sections, and the blade 2 is a side surface.

  As a preparation, each blade 2 is welded onto the disk 3. This welding is performed by a normal welding method. FIG. 3 shows what is obtained in this way. FIG. 3A shows the shroud 1 as it is, but FIG. 3B shows the blade 2 and the disk 3 integrated.

  Thereafter, as shown in FIG. 1, the shroud 1 is placed on the blade 2 and the disk 3 integrated.

  FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view. In FIG. 1, the hatched portions are removed to remove defects that are likely to occur at the start and end portions of the bead by removing them after welding.

  In this case, the butted portion between the members to be welded is a contact portion between the shroud 1 and the blade 2, and the butted portion between the members to be welded constitutes a T-butt butt weld joint, and the back surface thereof is in contact with this contact portion. Since it is the upper surface part of the corresponding shroud 1, irradiation of a high energy density beam is performed from the upper surface side of the shroud 1.

  In irradiation with a high energy density beam, a ring-shaped jig 4 having a flange is fitted on the outer peripheral side connecting the shroud 1 and the disk 3, and the shroud 1, the blade 2, and the disk 3 are formed from the central opening OP in the shroud 1. The ceramic particles, which are granular heat-resistant materials, are poured into the space S to be filled. The jig 4 prevents the ceramic particles from being washed away.

  In order to spread the ceramic particles 5 to every corner of the space S, the shroud 1, the blades 2, the disk 3, and the jig 4 are bound with an appropriate tool, and the ceramic particles 5 are filled, and this binding is performed. You should add vibration to your body. Alternatively, a liquid may be added to the ceramic particles 5 to form a mud, and the mud may be poured into the space S and welding may be performed when the liquid evaporates.

FIG. 4 shows the state of irradiation with a high energy density beam.
In FIG. 4, reference numeral 5 denotes ceramic particles filled in the space S, and the ceramic particles 5 in one space are removed, but are actually filled.

As the ceramic particles 5, 97 wt% of SiO ₂ , the residual is made of Fe ₂ O ₃ and Al ₂ O _3, and those having a particle diameter of 0.2 to 0.8 mm are used.

  In FIG. 4, 3A is the penetration part by high energy density beam welding, and the arrow has shown the irradiation direction of the high energy density beam.

  Even when the beam misalignment occurs, the ceramic particles 5 are present in the space S, so that the melt-through in the penetration portion 3A is prevented, and as a result, the target misalignment tolerance can be increased.

  Since the ceramic particles 5 follow the shape of the space S, the shape of the shroud 1, the blades 2, and the disk 3 that can alleviate the stress concentration at the butt portion may be processed in advance.

  Since the gap formed by the ceramic particles 5 satisfying the space S serves as a degassing passage during welding, leaving a space for corrosive gas or liquid to enter the welded portion (joined portion) And reliable welding can be obtained.

  In addition, when performing butt welding, a good and stable backside bead can be formed without special groove processing.

  After welding, the jig 4 is removed, the ceramic particles 5 that fill the space S are removed, and the part that has been deleted indicated by hatching in FIG. 1 is removed by appropriate machining to obtain the desired impeller. Can do. Since the ceramic particles 5 are merely a collection of powder particles, if the jig 4 is removed, the ceramic particles 5 will be washed away naturally, and if an appropriate impact is applied as necessary, the ceramic particles 5 will be separated from the impeller. There is no hardship.

  1 to FIG. 4, an example in which the shroud 1 is welded to the blade 2 and the disk 3 integrated in advance has been described. However, as shown in FIG. 5, the shroud 1 and the blade 2 integrated with the disk 3. Even when joining (welding), the present invention can be implemented and the object to be joined is not limited to the impeller.

  Further, the composition and particle size of the ceramic particles 5 are not limited to the above examples.

  Further, by using a welding flux as a filler instead of the ceramic particles 5, the performance of the weld metal can be improved. In particular, in this case, even if the welding flux particles adjacent to the penetration part 3A are melted by the heat of the high energy density beam, the welding metal can be integrated with the weld metal to form a satisfactory back wave filling the penetration part 3A. In addition, the manganese Mn and silicon Si contained have a deoxidizing action and forcibly remove the oxide film on the surface of the weld metal, so that the welded part not only becomes a strong bond between metals, but also the surface is cleaned. The

It is a figure which shows the assembly condition of the impeller which performs high energy density beam welding for describing one Embodiment of this invention. It is a figure which shows the form before the assembly of the member which comprises the impeller used by embodiment of FIG. It is a figure which shows the preparation stage of welding in embodiment of FIG. FIG. 2 is a diagram showing a welding situation in the embodiment of FIG. It is a figure which shows the preparation stage of welding in other embodiment of this invention.

Explanation of symbols

1. Shroud
2 ... feathers
3 Disc
4. Jig
5. Ceramic particles (granular heat resistant material)

Claims (2)

In the welding method using a high energy density beam that welds the butt portion by irradiating the butt portion with the back of the butt portion between the members to be welded,
A welding method using a high energy density beam, wherein a space formed by members to be welded constituting the butt portion is filled with a particulate material, and a high energy density beam is irradiated from the back surface of the butt portion. 2. A welding method using a high energy density beam according to claim 1, wherein the particulate material is ceramics or a welding flux.

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