JP5835913B2 - Welding repair method for directionally solidified material - Google Patents

Description

  The present invention relates to a method of repairing a damaged portion of a directionally solidified material formed by growing a single crystal material and a unidirectionally solidified material in a crystal direction by overlay welding.

  For example, a gas turbine blade (blade member such as a moving blade of a gas turbine) has many excellent characteristics such as strength characteristics and heat resistance, so it is formed by growing a single crystal material and a unidirectional solidified material in the crystal direction. Directional solidified material is used. On the other hand, the gas turbine blade 1 is exposed to a severe environment such as a high temperature during operation even when a directional solidified material is used, so that damage such as wear, thinning, cracking, etc. is likely to occur. It occurs on the end face 1b of (see FIG. 1). Conventionally, when damage is confirmed on the tip end portion of the gas turbine blade, the end face of the platform, or the like, the damaged portion is repaired (repaired) by overlay welding.

  On the other hand, when repairing damaged parts such as gas turbine blades of directional solidified material by overlay welding, the built-up with physical properties (strength characteristics, heat resistance, etc.) equivalent to the base material (directional solidified material) It is important to form the portion, and it is necessary to form the overlay by performing single crystal growth or overlay welding while growing the crystal in the same direction according to the crystal direction of the base material. However, it is very difficult to carry out overlay welding by growing single crystals or crystals in the same direction, and different crystals (polycrystals) are formed on the surface side of the overlay (bead surface side). End up.

  On the other hand, in Patent Document 1, by applying TIG overlay welding or plasma overlay welding to the damaged portion of the base material in a mushroom shape, the bead surface that is a different crystal is shaped and removed, and sequentially for each layer. A method of repairing a damaged portion of a unidirectionally solidified material by forming a built-up portion by repeatedly performing build-up welding and bead shaping removal is disclosed. And in this repair method, the bead surface side formed in the mushroom shape is shaped and removed, so that the different crystals are removed, and the built-up portion can be formed with the internal unidirectional solidified material grown in the same crystal direction. That is, it is possible to relatively easily form a built-up portion that is grown in the same crystal direction as the base material.

JP 2009-18345 A

  However, in the repair method disclosed in Patent Document 1 described above, overlay welding is performed in a mushroom shape, and the bead surface side formed in a mushroom shape is shaped and removed. .

  Here, G / R (G: temperature gradient between liquid phase and solid phase at the solidification interface, R: solidification rate when growing in the same crystal direction as the base material and overlay welding is applied to the end of the base material. ), That is, the larger the area where G / R is larger during overlay welding, the easier the crystal grows, and the single crystal material on which the single crystal is grown, or the crystal is grown in the same direction. Further, it is possible to suitably form the built-up portion with the unidirectional solidified material.

  And the area | region where G / R is large can be increased, so that welding speed is made small and welding output is made large. However, as the welding speed is decreased and the welding output is increased as described above, the end of the base material is melted too much, and the inconvenience that the base material and the built-up portion are melted occurs.

  In addition, it is difficult to apply to mushroom-like overlay such as TIG overlay welding and plasma overlay welding, but laser powder overlay welding is a welding method in which the temperature gradient and solidification rate are easy to control. . For this reason, a single crystal material or crystal in which a single crystal is grown by controlling the temperature gradient and solidification rate using laser powder overlay welding to prevent melting and increasing the area where G / R is large There has been a strong demand for a method that allows a built-up portion to be suitably formed with a unidirectional solidified material grown in the same direction.

The welding repair method for directionally solidified material according to the present invention is a method for repairing damage caused at the end of a directionally solidified material formed by growing a single crystal material and a unidirectionally solidified material in the crystal direction by overlay welding. Then, an overhang portion forming step for forming an overhang portion projecting outward in the thickness direction of the directional solidified material on the end portion side, and an overlay portion is formed on the end portion by laser powder overlay welding A build-up welding step, and a removal step of removing the surface side of the build-up portion and the overhang portion arranged on the overhang portion, and in the build-up welding step, the end portion and the overhang The build-up part is formed on a part, and in the removing step, at least the different crystal material generated on the surface of the build-up part is removed .

  In this invention, since the overhanging portion is formed on the end side of the base material (directional solidified material) such as a gas turbine blade in the overhanging portion forming step, the laser powder overlaying is performed in the overlay welding step. When forming weld overlay on the end of the base metal using welding, even if the welding speed is reduced and the welding output is increased, It is possible to prevent the raised portion from melting away.

  In the welding repair method for directionally solidified material according to the present invention, welding is performed when forming a buildup portion by performing buildup welding on an end portion of a base material (direction solidified material) using laser powder buildup welding. Even if the speed is reduced and the welding output is increased, it is possible to prevent the base metal and the built-up portion from being melted down by the overhanging portion. A raised portion can be formed.

  At this time, the temperature gradient and the solidification rate can be accurately controlled by forming the build-up portion by laser powder build-up welding.

  Therefore, according to the welding repair method of the directionally solidified material of the present invention, a single crystal material in which a single crystal is grown by increasing the G / R region while preventing the base material and the overlay from being melted down, Alternatively, it is possible to suitably form a built-up portion with a unidirectional solidified material in which crystals are grown in the same direction. Moreover, since it is not necessary to form a build-up part in a mushroom shape, it becomes possible to improve the work efficiency of welding work (repair work) compared with the past.

1 is a diagram showing a gas turbine blade (directionally solidified material formed by growing a single crystal material and a unidirectionally solidified material in a crystal direction) according to an embodiment of the present invention. FIG. It is a figure which shows the edge part which the damage of the gas turbine blade (directional solidification material) concerning one Embodiment of this invention produced. It is a figure which shows the state which formed the overhang | projection part in the edge part side of the gas turbine blade (directional solidification material) in the welding repair method of the direction solidification material which concerns on one Embodiment of this invention. In the welding repair method of the direction solidification material which concerns on one Embodiment of this invention, it is a figure which shows the state which performed overlay welding on the edge part side of a gas turbine blade (direction solidification material). In the welding repair method of the direction solidification material which concerns on one Embodiment of this invention, it is a figure which shows the state which shaped and removed the different crystal | crystallization part of the overhang | projection part and the overlaying part. It is a figure which shows the state which repair was completed in the welding repair method of the direction solidification material which concerns on one Embodiment of this invention. It is a figure which shows a laser powder build-up apparatus. In the welding repair method of the direction solidification material which concerns on one Embodiment of this invention, it is a figure which shows the state which laminates and forms the several build-up weld layer on the edge part of a gas turbine blade (direction solidification material). It is a figure which shows the modification of the welding repair method of the direction solidification material which concerns on one Embodiment of this invention, and is a figure which shows the state which formed the overhang | projection part using the member for overhang | projection. It is a figure which shows the modification of the welding repair method of the direction solidification material which concerns on one Embodiment of this invention, and is a figure which shows the state which formed the overhang | projection part using the member for overhang | projection. It is a X1-X1 line arrow directional view of FIG.

  Hereinafter, with reference to FIG. 1 to FIG. 8, a welding repair method for directionally solidified material according to an embodiment of the present invention will be described. In the present embodiment, the direction solidified material according to the present invention is described as being a gas turbine blade (a blade member such as a moving blade of a gas turbine) formed of a Ni-based alloy or the like. The gas turbine blade is formed by growing a single crystal material.

  First, the welding repair method (welding repair method for directionally solidified material) of the present embodiment is performed on the gas turbine blades (base material, blade member of the gas turbine) 1 such as the tip end 1a and the end surface 1b of the platform shown in FIG. This is a method of repairing damage such as wear, thinning, cracks, etc. occurring at the end 1c by overlay welding.

  And the welding repair method of this embodiment which repairs the damaged part 3 of the gas turbine blade 1 is shown in FIG.2 and FIG.3, and the overhang | projection part 2 which protrudes the thickness direction T1 outer side of the gas turbine blade 1 is shown. The overhanging portion forming step formed on the end portion 1c side of the damaged gas turbine blade 1 and the build-up portion 4 on the end portion 1c of the gas turbine blade 1 by laser powder overlay welding as shown in FIG. 5 and FIG. 6, and a removal step of shaping and removing the surface 4 a side of the built-up portion 4 and the overhang portion 2. Moreover, in this embodiment, in the overhang | projection part formation process, the overhang | projection part 2 is formed by laminating | stacking by laser powder overlay welding to the edge part 1c side of the gas turbine blade 1. FIG.

  More specifically, first, in the welding repair method of the present embodiment, for example, a laser powder cladding apparatus 5 as shown in FIG. 7 is used. This laser powder build-up device 5 is a conventionally well-known device. For example, the laser powder build-up device 5 includes a multi-axis robot 6 and a lens unit 7. A laser oscillation device 10 that is connected to the irradiation nozzle 8 and oscillates the laser and a laser irradiation nozzle 8 that is connected to the laser irradiation nozzle 8 via the shield gas pipe 11 and supplies a shield gas to the laser irradiation nozzle 8 (near). A shield gas supply source 12 and a powder supply device 13 for supplying the same kind of metal powder as the base material 1 to the laser irradiation nozzle 8 are provided.

  When repairing the damaged portion 3 of the gas turbine blade 1 (hereinafter also referred to as a base material) using such a laser powder overlaying device 5, as shown in FIGS. Overlay welding 2 is performed by the body build-up device 5 so as to protrude from the side surface of the base material 1 on the end 1c (damaged part 3) side to the outside in the thickness direction T1 of the base material 1, thereby forming the overhang portion 2. .

  Next, as shown in FIGS. 4 and 8, build-up welding is performed on the end portion 1 c (end face) of the base material 1 by the laser powder build-up device 5. At this time, build-up welding is sequentially repeated until a predetermined build-up height set according to the amount of damage such as wear, thinning, and cracking is obtained, and a plurality of build-up weld layers 15 are formed in layers. . Further, at the stage where each build-up weld layer 15 is formed, a different crystal 16 is generated on the entire surface side (bead surface) of each build-up weld layer 15, and each build-up weld layer 15 covered with this different crystal portion 16. , A single crystal (single crystal material) 17 grows in the same crystal direction as the single crystal of the base material 1, and is built up in the T2 direction (stacking direction).

  Furthermore, in the present embodiment, when the build-up weld layer 15 is newly formed on the lower build-up weld layer 15 in sequence, as shown in FIG. A new build-up weld layer 15 is formed while remelting the crystal portion 16. Thereby, as shown in FIG. 4, the build-up portion 4 in the form of laminating a plurality of build-up weld layers 15 is the top side (from the end portion 1c of the base material 1 to the outermost side in the stacking direction T2), Different crystal portions 16 are formed on both sides of the base material 1 in the thickness direction T1, and inside the single crystal 17 grows in the same crystal direction as the single crystal of the base material 1, and builds up in the T2 direction. It is formed.

  And in this embodiment, as shown in FIG.4 and FIG.8, when each build-up welding layer 15 is formed in a build-up welding process, it builds up on the edge part 1c and the overhang | projection part 2 of the base material 1. FIG. The built-up portion 4 formed by laminating each build-up weld layer 15 and a plurality of build-up weld layers 15 is formed so as to perform welding. Thereby, the different crystal parts 16 formed on both sides (surface side) in the thickness direction T1 of the base material 1 of the built-up part 4 are arranged on the overhang part 2.

  Next, after laminating a plurality of build-up weld layers 15 as described above to form the build-up portion 4, as shown in FIGS. 5 and 6, the removal step was arranged on the overhang portion 2 The different crystal portions 16 on both sides in the thickness direction T1 of the base material 1, the uppermost different crystal portion 16 and the overhang portion 2 are removed by machining or electric discharge machining. At this time, for example, the different crystal 16 is completely removed by shaping and removing so that the thickness T1 of the base material 1 is equal to the thickness of the built-up portion 4, and the single crystal material 17 grown in the same crystal direction is removed. A built-up portion 4 'is formed. As a result, repair work such as wear, thinning, cracking, etc. occurring at the end 1c of the tip end 1a of the gas turbine blade 1 and the end face 1b of the platform is completed.

  On the other hand, in the welding repair method of this embodiment, since the overhang | projection part 2 is formed in an overhang | projection part formation process, each build-up welding layer 15 is used for the build-up welding process using laser powder overlay welding. Even when the welding speed is reduced and / or the welding output is increased when forming the (build-up part 4), the base material 1 and the build-up part 4 are reliably prevented from being melted by the overhang part 2. The

  And by providing the overhang | projection part 2 in this way, even if it reduces welding speed and / or enlarges a welding output, the base material 1 and the build-up part 4 are prevented from melt | disconnecting, thereby a laser. While accurately controlling the temperature gradient and the solidification rate by powder overlay welding, the value of G / R (G: temperature gradient between liquid phase and solid phase at the solidification interface, R: solidification rate) can be increased. Thereby, the built-up portion 4 ′ is formed by growing the single crystal 17 efficiently and effectively.

  Therefore, in the welding repair method for the directionally solidified material of the present embodiment, when forming the build-up portion 4 by performing build-up welding on the end portion 1c of the base material 1 using laser powder build-up welding, Even if the welding speed is reduced and the welding output is increased, the base material 1 and the built-up portion 4 can be prevented from being melted down by the overhang portion 2. For this reason, it is possible to increase the value of G / R and grow the single crystal 17 efficiently and effectively to form the built-up portion 4 (4 ').

  At this time, the temperature gradient and the solidification rate can be accurately controlled by forming the build-up portion 4 by laser powder build-up welding.

Therefore, according to the welding repair method of the directionally solidified material of the present embodiment, a region where G / R is large (for example, G / R> 10 ⁴ or more while preventing the base material 1 and the build-up portion 4 from being melted). ) Is increased, and the built-up portion 4 (4 ′) in which the single crystal 17 is preferably grown in the same crystal direction can be formed in the T2 direction. Moreover, since it is not necessary to form a build-up part in a mushroom shape, it becomes possible to improve work efficiency compared with the past.

  Furthermore, in the welding repair method for the directionally solidified material according to the present embodiment, the overhang portion 2 is formed by overlay welding in the same manner as the overlay portion 4 so that the work can be performed more efficiently. It becomes possible. Then, after the overlaid portion 2 is formed, by removing the different crystal portion on the overhang portion 2 by machining or the like, the built-up portion 4 that is preferably grown in the same crystal direction is formed more efficiently. It becomes possible to do. At this time, the build-up portion 4 is formed on the end portion 1c of the base material 1 and the overhang portion 2, and the different crystal portion 16 on the overhang portion 2 is removed together with the overhang portion 2. It becomes possible to work more efficiently.

  As mentioned above, although one Embodiment of the welding repair method of the direction solidification material which concerns on this invention was described, this invention is not limited to said one Embodiment, It can change suitably in the range which does not deviate from the meaning. .

  For example, in the present embodiment, the directionally solidified material according to the present invention has been described as being a gas turbine blade 1 of a single crystal material. However, the present invention is directed to directional solidification formed by growing crystals in the same direction. The present invention can be applied to any case in which damage caused to the end portion 1c of the material 1 is repaired by overlay welding, and the directional solidified material is not necessarily limited to the gas turbine blade 1.

  Further, in the present embodiment, the overlaid portion 4 is formed on the overhanging portion 2 so that the different crystal portion 16 of the overlaid portion 4 is arranged outside the base material 1 in the thickness direction T1. The description has been made assuming that the different crystal portion 16 is removed together with the portion 2. On the other hand, in the present invention, it is not always necessary to dispose the different crystal portion 16 of the built-up portion 4 outside the base material 1 by forming the built-up portion 4 on the overhanging portion 2. May be. And in this case, the overhang | projection part 2 exhibits the outstanding effect of preventing that the edge part 1c of the base material 1 and the build-up part 4 melt.

  Furthermore, in the present embodiment, the overhang portion 2 is formed by overlay welding on the end portion 1c of the base material 1, but as shown in FIGS. 9, 10, and 11, for example, the base material The overhanging portion 2 may be formed by integrally attaching a jig (the overhanging member 18) made of the same material as 1 to the end 1 c side of the base material 1. In this case, the jig 18 may be attached to the end 1c side of the base material 1 by spot welding or the like as shown in FIG. Alternatively, as shown in FIGS. 10 and 11, a pair of jigs 18 arranged so as to sandwich the base material 1 may be fixed by fixing means 19 and attached to the end 1 c side of the base material 1. In this case, the jig 18 can be easily attached and detached.

1 Gas turbine blade (directional solidified material, base material, single crystal material, gas turbine blade member)
DESCRIPTION OF SYMBOLS 1a Chip end part 1b Platform end face 1c End part 2 Overhang part 3 Damaged part 4 Overlay part 4a Surface 4 'Overlay part 5 Laser powder overlay apparatus 6 Multi-axis robot 7 Lens unit 8 Laser irradiation nozzle 9 Optical fiber DESCRIPTION OF SYMBOLS 10 Laser oscillation apparatus 11 Shield gas pipe 12 Shield gas supply source 13 Powder supply apparatus 15 Overlay welding layer 16 Different crystal (different crystal part)
17 Single crystal (single crystal part)
18 Jig (overhanging member)
19 Fixing means T1 Thickness direction T2 Stacking direction (Building-up direction)

Claims (3)

It is a method of repairing damage caused at the end of a directionally solidified material formed by growing a single crystal material and a unidirectionally solidified material in the crystal direction by overlay welding,
An overhang portion forming step of forming an overhang portion projecting outward in the thickness direction of the directional solidified material on the end side;
Overlay welding process for forming an overlaid portion on the end by laser powder overlaid welding ;
A removal step of removing the surface side of the build-up portion and the overhanging portion arranged on the overhanging portion;
Equipped with a,
In the build-up welding process, the build-up part is formed on the end part and the overhang part,
The welding repair method for a directionally solidified material, wherein in the removing step, at least the heterocrystalline material generated on the surface of the build-up portion is removed . In the welding repair method of the directionally solidified material according to claim 1 ,
The overhanging portion is formed by overlay welding on the end portion, or formed by integrally attaching an overhanging member to the end portion. In the welding repair method of the direction solidified material according to claim 1 or 2 ,
The directional solidified material welding repair method, wherein the directional solidified material is a blade member of a gas turbine.

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