JP2005188481A - Method of re-covering stellite strip in surface of turbine blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of re-covering stellite strips capable of accurately re-covering the stellite strips by improving quality in brazing without requiring skillfulness. <P>SOLUTION: New strips 3 are adhered to a surface of the turbine blade 2, from which worn stellite strips 3 were already eliminated, through a brazing material, and the new stellite strips are adhered to the surface of the turbine blade 2 by using a constraining tool 20 in a plurality of positions. The surface of the turbine blade 2, to which the new stellite strips 3 are adhered, is heated by using a heating coil 13, while controlling temperature of the turbine blade 2 by using a thermometer 14 directly provided in the surface of the turbine blade 2, to which the new stellite strips 3 are adhered, and the new stellite strips 3 are thereby brazed to the turbine blade 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for replacing a stellite piece on a turbine blade surface worn by cavitation erosion.

Turbine blades operating in wet steam containing water droplets are generally known to suffer from cavitation erosion, so in order to prevent wear by this cavitation erosion, the turbine blades are arranged radially from the turbine shaft. A stellite piece is brazed along the thick side edge of the turbine blade extending outward.
If such a turbine blade has been used for many years and the brazed stellite piece is worn, it is necessary to remove the worn stellite piece and replace it with a new stellite piece. In general, the replacement work involves removing the turbine blades that require repair from the rotor and transporting them to a repair shop for repair. In this case, in addition to the actual repair work, the turbine blades are removed and repaired from the site. Excessive work such as transportation to the factory, from the repair shop to the site, and installation of the turbine blades occurs, resulting in prolonged turbine downtime.
For this reason, a method of exchanging stellite pieces with the turbine blades attached to the rotor has been studied (for example, Patent Document 1 below). Specifically, the worker heats the worn stellite piece with a gas burner, melts the brazing material, peels the stellite piece from the wing, and polishes and leveles the surface of the wing from which the stellite piece has been peeled off. Subsequently, a new stellite piece is placed on the surface and cut, and the stellite piece whose size is adjusted is overlapped with a silver brazing sheet having a thickness of about 0.2 mm to 0.3 mm between the wings, It fixes to a fixed position using a jig | tool, the surface of a stellite piece is heated from 650 degreeC to 700 degreeC with a gas burner, and it brazes.
JP 2003-71560 A

By the way, when proceeding with replacement work at the site as described above, if temperature irregularities occur in the turbine blades, the blades may partially deform and twist and the stellite pieces may not be brazed precisely. is there. In addition, when the turbine blade is made of 13Cr martensitic stainless steel, permanent deformation due to martensitic transformation is likely to occur in combination with deformation due to temperature unevenness as described above. Therefore, the turbine blades must be heated uniformly so as not to cause temperature unevenness, and a high skill level is required for the operator.
Further, even if the turbine blades can be heated uniformly, the blades expand as a whole by heating and cannot be shrunk when the heating is stopped, so that there is a possibility that the jig to which the stellite piece is fixed loosens. Therefore, it is necessary to adjust the jig in consideration of looseness, and a high skill level is required for the operator.
In addition, although a plurality of turbine blades are implanted in the rotor, the turbine blades to be repaired expand as a result of heating as described above, so interference with adjacent turbine blades must be considered. After all, a high level of skill is required of the worker.

  The present invention has been made in view of the above circumstances, and provides a stellite piece replacement method capable of precisely performing stellite piece replacement by improving the brazing quality without requiring a high level of skill. It is an object.

  As means for solving the above-described problems, a method for replacing the stellite piece on the surface of the turbine blade having the following configuration, a repositioning jig, and a brazing material are employed.

  That is, in the method for replacing the stellite piece on the surface of the turbine blade according to claim 1 of the present invention, the new stellite piece is brought into close contact with the surface of the turbine blade from which the worn stellite piece has been removed by sandwiching a brazing material. Is attached to the surface of the turbine blade using a restraining jig at a plurality of locations, and the temperature control of the turbine blade is performed using a thermometer installed directly on the surface of the turbine blade to which the new stellite piece is attached. The surface of the turbine blade, to which the new stellite piece is closely attached, is heated using an induction heating coil, and the new stellite piece is brazed to the turbine blade.

  In the present invention, temperature unevenness is unlikely to occur in the turbine blade, and the blade is not partially deformed or twisted, so that the stellite piece can be precisely brazed to the surface of the blade.

The restraining jig according to claim 2 is a restraining jig used for closely attaching the stellite piece to the surface of the turbine blade with the brazing material interposed therebetween,
A front hook portion locked to a front edge of the turbine blade, a rear hook portion locked to a rear edge of the turbine blade, an intermediate portion pivotally supporting the front hook portion, and the intermediate portion An elastic member that exerts a tension that connects the portion and the rear hook portion and draws them together,
The front hook portion is formed with a pressing portion that is pressed against the stellite piece by a tension exerted by the elastic member.

  In the present invention, the use of the elastic member makes it difficult for the restraining jig to loosen, and there is no need to adjust the jig in consideration of the loosening as in the prior art. Can be repaired.

The gap management jig according to claim 3 is a gap management jig used to maintain a constant gap between two turbine blades that are implanted in the rotor and are adjacent to each other in the front-rear direction.
A wedge-shaped portion inserted in a gap between a shroud portion provided at a blade tip of one turbine blade of the two turbine blades and a shroud portion provided at a blade tip of the other turbine blade; and the wedge-shaped portion Between the base portion projecting so as to form a V-shape with one side as a side, a female screw hole formed through the base portion toward the wedge-shaped portion, and the wedge-shaped portion screwed into the female screw hole. And a bolt sandwiching the shroud portion.

  In the present invention, by keeping the gap between the shroud portions of two adjacent turbine blades constant, it becomes possible to prevent interference between adjacent turbine blades and perform precise repairs.

The branch burner according to claim 4 is a branch burner for heating the surface of a turbine blade,
At least a main pipe portion having a length to be heated of the turbine blade, and a plurality of burner nozzles provided in the main pipe portion so as to be separated from each other in the length direction;
The plurality of burner nozzles can change the amount of protrusion from the main pipe portion and the flame injection direction in accordance with the surface shape of the opposed turbine blades.

  In the present invention, it is possible to uniformly preheat turbine blades so as not to cause temperature unevenness by appropriately setting the distance and direction of each burner nozzle to the blade surface according to the surface shape of the blade. Thus, deformation and twisting of the wing can be prevented, and brazing accuracy can be increased.

A method for attaching a stellite piece on a surface of a turbine blade according to claim 5, wherein the stellite piece is brought into close contact with the surface of the turbine blade through a brazing material, and the stellite piece is made to adhere to the turbine blade along the turbine blade. A method for attaching a stellite piece on a surface of a turbine blade, wherein the stellite piece is brazed to the turbine blade by heating using a placed induction heating coil,
The heat generation amount of the portion adjacent to each part of the induction heating coil is set in proportion to the thickness of each part of the turbine blade.

  In the present invention, a thicker shroud portion is supplied with a larger amount of heat than a thin turbine blade, so that there is no heating delay in the shroud portion so that temperature unevenness does not occur in the entire turbine blade. Heating can be performed uniformly, and as a result, deformation and twisting of the blade can be prevented, and brazing accuracy can be increased.

The method for attaching a stellite piece on a surface of a turbine blade according to claim 6 is such that the stellite piece is brought into close contact with the surface of the turbine blade with a brazing material interposed therebetween, and the turbine wing having the stellite piece brought into close contact is sandwiched between the turbine blades. A method for attaching a stellite piece on a surface of a turbine blade, wherein the stellite piece is brazed to the turbine blade by heating using an induction heating coil disposed on the turbine blade,
The thickness of the turbine blade in the portion sandwiched between the heating coils is set to a thickness that is not affected by the magnetic field canceling effect of the induction heating coil.

  In the present invention, there is little deviation of the heating pattern due to misbalance of the coil setting at the time of local brazing, and improvement in temperature accuracy can be expected. In addition, the heating coil 13 can be easily positioned and the work can be efficiently performed.

The method for attaching a stellite piece on the surface of a turbine blade according to claim 7 is characterized in that the stellite piece is brought into close contact with the surface of the turbine blade with a brazing material interposed therebetween, and the turbine wing having the stellite piece brought into close contact is disposed along the turbine blade. A method for attaching a stellite piece on a surface of a turbine blade, wherein the stellite piece is brazed to the turbine blade by heating using a placed induction heating coil,
A brazing material is formed into particles, and a brazing material in which an oxide film is formed on the surface of each particle is mixed with a binder and applied to the surface of the stellite piece to form a coating of brazing material, on the surface of the turbine blade, The stellite pieces are brought into close contact with the film interposed therebetween.

  The brazing material according to claim 8 is characterized in that it is granulated and an oxide film is formed on the surface of each particle.

  In the present invention, it becomes easy to keep the gap between the stellite piece and the surface of the turbine blade constant, and brazing quality can be improved.

A method for attaching a stellite piece on a surface of a turbine blade according to claim 9, wherein the stellite piece is brought into close contact with the surface of the turbine blade through a brazing material, and the stellite piece is brought into close contact with the turbine blade along the turbine blade. A method for attaching a stellite piece on a surface of a turbine blade, wherein the stellite piece is brazed to the turbine blade by heating using a placed induction heating coil,
The stellite pieces are divided into a plurality of pieces, and these divided bodies are arranged on the surface of the turbine blade without leaving a gap therebetween.

  In the present invention, the flux contained in the brazing material is discharged to the outside from the joint of the adjacently arranged divided bodies, and only the metal component of the brazing material remains between the stellite pieces and the surface of the turbine blade. Since both are fixed, high-quality brazing becomes possible.

A method for attaching a stellite piece to a turbine blade surface according to claim 10 is provided, wherein a stellite piece is closely attached to a surface of the turbine blade with a brazing material interposed therebetween, and the turbine blade having the stellite piece closely attached is provided along the turbine blade. A method for attaching a stellite piece on a surface of a turbine blade, wherein the stellite piece is brazed to the turbine blade by heating using a placed induction heating coil,
A groove is formed in the brazing surface of the stellite piece.

  In the present invention, the flux contained in the brazing material flows into the groove, the surface excluding the groove of the stellite piece adheres closely to the surface of the turbine blade, and only the metal component of the brazing material remains in this part, so both are fixed. High quality brazing is possible. Further, the formation of the groove makes it easy to bend the stellite piece and makes it very easy to align the stellite piece with the groove portion.

  According to the present invention, high-quality brazing can be realized and the stellite pieces can be precisely replaced without requiring deformation of the turbine blades without requiring a high level of skill. Thereby, the further improvement of turbine performance is realizable by preventing a deformation | transformation of a turbine blade. In addition, by realizing high-quality brazing, it is possible to suppress high-temperature fatigue of the turbine blade and to prolong the wear life. Further, the maintenance interval of the turbine blades becomes longer, and the cost for maintenance work can be reduced.

A first embodiment of the present invention will be described with reference to FIGS.
In FIG. 1, the structure of the induction heating apparatus 10 for replacing the stellite piece 3 brazed on the surface of the turbine blade 2 implanted in the rotor 1 is shown. The induction heating device 10 includes a high frequency power supply device 11, a matching transformer 12 that converts the output voltage and frequency of the high frequency power supply device 11, a U-shaped heating coil 13 that heats the surface of the turbine blade 2, and the turbine blade 2. A thermometer 14 that measures the surface temperature and a cooling device 15 that guides cooling air to the heating coil 13 to prevent the heating coil 13 from overheating are provided.
An inverter power supply device is adopted as the high frequency power supply device 11. The heating coil 13 is configured to have a desired size and shape by connecting pipe-shaped connecting elements. The thermometer 14 employs a high-temperature bonding type temperature gauge that is directly bonded to the surface on the ventral side of the turbine blade 2, and a plurality of the temperature gauges 14 are installed apart from each other in the span direction and the blade width direction of the turbine blade 2. Yes. The high frequency power supply 11 and the matching transformer 12 are connected via a power cable 16, and the matching transformer 12 is connected to a heating coil 13. The high frequency power supply device 11 and the cooling device 15 are connected via a power cable 17, and the cooling device 15 and the heating coil 13 are connected via an air supply hose 18 that relays the high frequency power supply device 11 and the matching transformer 12. Yes.

  FIG. 2 shows a restraining jig 20 for restraining the stellite piece 3 to the turbine blade 2 and holding it in a predetermined position on the blade surface. The restraining jig 20 includes a front hook portion 21 that is locked to the front edge of the turbine blade 2, a rear hook portion 22 that is locked to the rear edge of the turbine blade 2, and a front hook portion 21 that is pivotable. Both ends are hooked on the supporting intermediate portion 23, the bolt 23 a screwed to the intermediate portion 23, and the bolt 22 a screwed to the rear hook portion 22, and the front and rear hook portions 21 and 22 are drawn together. And a coil spring (elastic member) 24 that exerts tension.

  The front hook portion 21 is bent so as to get over the front edge of the turbine blade 2 and is in contact with the abdominal side surface, a proximal end portion 21b pivotally supported by the intermediate portion 23, a distal end portion 21a and a base portion It has an abdominal part (pressing part) 21c located in the middle of the end part 21b and in contact with the stellite piece 3 arranged on the surface of the turbine blade 2. The intermediate portion 23 is formed with three female screw holes 23b into which the bolts 23a are screwed, spaced apart in the width direction of the wing, so that the bolts 23a are screwed into any of the female screw holes 23b. It has become.

In the restraining jig 20, the front hook portion 21 is locked to the front edge of the turbine blade 2, the rear hook portion 22 is locked to the rear edge, and a tension is introduced between the two by the coil spring 24, whereby the turbine blade 2. Attached to. In this way, the front end portion 21 a of the front hook portion 21 that contacts the abdominal side surface of the turbine blade 2 serves as a fulcrum, the base end portion 21 b is pulled to the rear edge side, and the abdominal portion 21 c is disposed on the surface of the turbine blade 2. It is pressed by the piece 3. As a result, the stellite piece 3 can be constrained to the turbine blade 2 and held at a predetermined position on the blade surface.
By the way, since the turbine blade 2 has different blade width direction dimensions, torsional shapes, and cross-sectional shapes at each position in the span direction, the stellite piece 3 can be pressed with a uniform force with only one type of restraining jig 20. Is difficult. Accordingly, several types of coil springs 24 having different lengths are prepared, and the position of the female screw hole 23b to which the bolt 23a is to be screwed and the length of the coil spring 24 are appropriately selected, and any restraining jig attached to the turbine blade 2 is selected. 20 is adjusted so that the abdomen 21c is pressed against the stellite piece 3 with substantially the same force.

  FIG. 3 shows a gap management jig 30 that is implanted in the rotor 1 and inserted between the shroud portions 4 of the two turbine blades 2 adjacent to each other in the front and rear direction of rotation to keep the gap between the blades constant. . The clearance management jig 30 includes a concave portion 5 on the blade trailing edge side of the shroud portion 4 of the turbine blade 2 positioned forward in the rotational direction and a convex portion on the blade leading edge side of the shroud portion 4 positioned rearward in the rotational direction. 6, a wedge-shaped portion 31 inserted between the base portion 32, a base portion 32 protruding so as to form a V shape with the wedge-shaped portion 31 as one side, and a female screw hole formed by penetrating the distal end of the base portion 32 toward the wedge-shaped portion 31. And a bolt 33 to be screwed into 32a.

  In the gap management jig 30, the wedge-shaped portion 31 is inserted between the concave portion 5 and the convex portion 6 of the front and rear shroud portions 4, the bolt 33 is screwed into the female screw hole 32a of the base portion 32, and the tip thereof is rotated. It is fixed between the blades by being pressed from the abdomen side by the shroud portion 4 of the turbine blade 2 positioned forward in the direction. Thereby, even if the turbine blade 2 is heated and expanded, the gap between the shroud portions 4 of the two adjacent turbine blades 2 can be kept constant.

  FIG. 4 shows a branch burner 40 for uniformly heating the surface of the turbine blade 2 without temperature unevenness. The branch burner 40 includes a main pipe portion 41 that is comparable to the length of the portion to be heated of the turbine blade 2, and a plurality of burner nozzles 42 that are provided in the main pipe portion 41 so as to be separated in the length direction of the main pipe portion 41. , Connected to a hose 43 for supplying gas. The burner nozzle 42 can change the protrusion amount (length) and direction (angle) from the main pipe portion 41 in accordance with the surface shape of the opposing turbine blade 2.

  The branch burner 40 is arranged so that the burner nozzle 42 faces the turbine blade 2 along the span direction of the blade during the removal operation of the worn stellite piece and the attaching operation of the new stellite piece. The amount of projection (length) and direction (angle) from the main pipe portion 41 are changed in accordance with the surface shape of the turbine blade 2. Thereby, it is possible to heat the turbine blade 2 uniformly so as not to cause temperature unevenness.

  FIG. 5 shows a structure of a thermocouple type simple caulking type temperature gauge employed as the thermometer 14. The temperature gauge includes a pair of leg portions 45 and a temperature detection unit 46 provided at the base end of the leg portion 45. Each leg portion 45 is provided with a spot fixing plate 47 for fixing the temperature gauge to the turbine blade 2, and the temperature detecting portion 46 is provided with an insulating portion 48 for canceling the influence of radiant heat.

  As shown in FIG. 6, the temperature gauge uses a temperature gauge mounting jig 49 disposed so as to straddle the front edge of the turbine blade 2 with the temperature detection unit 46 abutting on the side surface on the ventral side of the turbine blade 2. The detector 46 is pressed against the surface of the turbine blade 2 and the spot fixing plate 47 is spot-welded to the surface of the turbine blade 2, whereby the surface temperature of the turbine blade 2 can be directly measured.

Hereinafter, the method of replacing the stellite piece 3 on the surface of the turbine blade 2 will be described separately for the operation of removing the worn stellite piece and the operation of attaching a new stellite piece.
[Removal work of worn stellite pieces]
First, the turbine blade 2 to which the stellite piece is to be replaced is identified from among the turbine blades 2 implanted in the rotor 1, and the rotor 1 is rotated so that the identified turbine blade 2 faces substantially in the horizontal direction, and then stopped. Let 3 is attached between the shroud portion 4 of the identified turbine blade 2 and the shroud portion 4 of the turbine blade 2 adjacent to the front in the rotational direction. Moreover, the thermometer 14 which consists of the temperature gauge of FIG. 5 is installed in several places of the side surface of the specified turbine blade 2 on the ventral side.
After that, the turbine blade 2 is preheated uniformly using the branch burner 40 of FIG. Further, the worn stellite piece 3 on the surface of the turbine blade 2 is heated with a gas burner from 650 ° C. to 700 ° C. to melt the brazing material and peel off the worn stellite piece 3. Furthermore, the brazing material remaining in the groove (the portion from which the stellite piece 3 has been removed) is heated by a gas burner to be melted and removed. Preferably, the remaining brazing material is scraped off using a grinder or the like.

[Attaching a new stellite piece]
Next, a new stellite piece 3 is placed on the groove portion of the turbine blade 2 and cut, and the stellite piece 3 whose size is adjusted is overlapped with a sheet of brazing material between the groove portion and FIG. The fixed jig 20 is used to fix in place. As the brazing material sheet, a sheet made of BAg3 silver having a thickness of 0.2 mm to 0.3 mm is used. Further, a plurality of restraining jigs 20 are attached at substantially equal intervals in the span direction of the turbine blade 2 and press the new stellite piece 3 with substantially the same force. Furthermore, one of the two parallel legs of the U-shaped heating coil 13 is disposed on the side surface on the ventral side of the turbine blade 2 and the other is disposed on the side surface on the back side of the turbine blade 2 so that both are substantially parallel to the span direction. Fix it so that

  Next, the induction heating device 10 is operated, and a high frequency current is caused to flow from the high frequency power supply device 11 to the heating coil 13 via the matching transformer 12. When a high frequency current flows through the heating coil 13, a magnetic field is generated, and an induced current flows in the turbine blade 2 and the stellite piece 3 due to this magnetic field, and the turbine blade 2 and the stellite piece 3 generate heat due to this current. When the turbine blade 2 and the stellite piece 3 generate heat, the temperature of the heating coil 13 also rises, so that cooling air is guided from the cooling device 15 to the heating coil 13 to prevent the heating coil 13 from overheating.

The high frequency power supply device 11 controls the output so that the surface temperature of the turbine blade 2 measured by the thermometer 14 changes according to a predetermined pattern within a certain period. Preferably, the surface temperature of the turbine blade 2 is changed by PID control.
FIG. 7 shows an example of a temperature change pattern. In this pattern, the surface temperature of the turbine blade 2 is increased linearly from the start of heating to reach 100 ° C. after about 10 seconds, and then maintained at 100 ° C. for about 20 seconds. While heating the turbine blade 2 to raise the surface temperature, by maintaining the temperature constant for a certain period, heat generated in the turbine blade 2 is conducted to the inside of the blade, Both outside are heated without uneven temperature.
Subsequently, the surface temperature of the turbine blade 2 is increased again linearly to reach about 400 ° C. after about 10 seconds, and then maintained at 400 ° C. for about 10 seconds. Subsequently, the surface temperature of the turbine blade 2 is increased linearly to reach about 700 ° C. after about 10 seconds, and then maintained at 700 ° C. for about 1 minute. Accordingly, the brazing material sheet interposed between the surface of the turbine blade 2 and the stellite piece 3 is sufficiently melted, and the surface of the turbine blade 2 and the stellite piece 3 can be wetted with the brazing material. .
Subsequently, the surface temperature of the turbine blade 2 is linearly lowered to reach about 600 ° C. after about 10 seconds, and then maintained at 600 ° C. for about 10 seconds. Subsequently, the surface temperature of the turbine blade 2 is linearly lowered again to reach about 100 ° C. after about 10 seconds, and then maintained at 100 ° C. for about 30 seconds, and the heating is finished. As the surface temperature of the turbine blade 2 is lowered, heat is dissipated from the turbine blade 2 by keeping the temperature constant for a certain period of time, and the turbine blade 2 can maintain the temperature without unevenness in the temperature inside and outside. Reduce.

  When the heating is completed, the heating coil 13 and the thermometer 14 attached to the turbine blade 2 are removed, and the replacement work is completed. After completion of the re-covering operation, the presence or absence of defects such as cavity defects, welding defects, blow holes, etc. are inspected using an ultrasonic inspection method or the like.

When the stellite piece 3 on the surface of the turbine blade 2 is replaced as described above, the following effects can be expected.
First, the restraining jig 20 can restrain the stellite piece 3 to the turbine blade 2 and hold it at a predetermined position on the blade surface. Since the turbine blade 2 has different blade width direction dimensions, torsional shapes, and cross-sectional shapes at each position in the span direction, it is difficult to press the stellite piece 3 with uniform force with only one type of restraining jig 20. However, the restraining jig 20 can apply substantially the same pressing force to the stellite piece 3 by any restraining jig 20 attached to the turbine blade 2 by appropriately selecting the length and attachment method of the coil spring 24. it can. Further, the use of the coil spring 24 makes it difficult for the restraining jig 20 to be loosened, and it is not necessary to adjust the jig in consideration of the loosening as in the conventional case. Is possible.

  Even when the turbine blade 2 is heated and expanded by the gap management jig 30, the gap between the shroud portions 4 of the two adjacent turbine blades 2 can be kept constant. When a specific turbine blade 2 is heated, interference may occur between the front and rear turbine blades 2 that are not heated. Interference is particularly likely to occur in the shroud portions 4 or other stub portions that are adjacent to each other at a short distance, so that the gap between the shroud portions 4 of the two adjacent turbine blades 2 is formed by the gap management jig 30. By keeping constant, it is possible to prevent interference between the adjacent turbine blades 2 and perform precise repairs.

  The entire turbine blade 2 can be uniformly heated by the branch burner 40 and the heating coil 13 using high-frequency current so as not to cause temperature unevenness. If temperature unevenness occurs in the turbine blade 2, the blade may be partially deformed or twisted, and the stellite pieces may not be precisely brazed. By preheating uniformly so as not to occur, it is possible to prevent the blade from being deformed or twisted and to improve the brazing accuracy.

  The thermocouple-type simple caulking type temperature gauge employed as the thermometer 14 can greatly improve the measurement accuracy and responsiveness.

  By controlling the output so that the surface temperature of the turbine blade 2 changes according to a predetermined pattern within a certain period by the high-frequency power supply device 11, the operator is not forced to have high skill and in a short time. Exquisite repairs are possible. Further, since the thermal stress generated in the turbine blade 2 is kept low, thermal deformation generated in the blade due to the thermal stress, distortion remaining in the blade after cooling, and the like can be reduced, and deterioration in performance of the turbine blade 2 can be prevented. Can do.

Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the component already demonstrated in the said 1st Embodiment, and description is abbreviate | omitted.
In FIG. 8, the form of the heating coil 13 installed from the blade end side of the turbine blade 2 is shown. Since the blade tip is provided with a shroud portion 4 that is considerably thicker than the blade portion, in order to heat the thick shroud portion 4 to a substantially uniform temperature as in the other portions, the shroud portion 4 It is necessary to supply more heat than the others. Therefore, in the present embodiment, the heating coil 13 disposed closer to the thick shroud portion 4 than the tip portion 13a of the heating coil 13 disposed closer to the side surface of the thin turbine blade 2 is used. The resistance of the base end portion 13b is increased. Specifically, the base end portion 13b of the heating coil 13 is reduced in cross-sectional area, and the cross-sectional area of the tip end portion 13a is increased, so that the heating amount of the heating coil 13 as a whole is not changed, and the base end of the heating coil 13 is changed. The amount of heat generated from the portion 13b is increased, and the amount of heat generated from the tip portion 13a is decreased. As a result, a larger amount of heat is supplied to the shroud portion 4 than the thin turbine blade 2, so that the entire turbine blade 2 is uneven in temperature without causing a heating delay in the thick shroud portion 4. As a result, the blade can be prevented from being deformed or twisted, and the brazing accuracy can be increased.

  FIG. 9 shows a modification of the present embodiment. In this modification, apart from the heating coil 13 arranged close to the side surface of the thin turbine blade 2, a rod-shaped heating coil 50 is arranged close to the shroud portion 4 and separately provided. It is connected to the transformer 51. The rectifying transformers 12 and 51 are connected to the high-frequency power supply device 11 in parallel. Specifically, the shroud portion 4 that is thicker than the wing portion is heated together with the heating coil 13 by a bar-shaped heating coil 50 provided separately. As a result, a larger amount of heat is supplied to the shroud portion 4 than the thin turbine blade 2, so that the entire turbine blade 2 is uneven in temperature without causing a heating delay in the thick shroud portion 4. As a result, the blade can be prevented from being deformed or twisted, and the brazing accuracy can be increased.

  FIG. 10 shows another modification of the present embodiment. In this modification, the base end portion 13 b of the heating coil 13 disposed close to the thick shroud portion 4 is deformed so as to meander or circulate around the shroud portion 4. Specifically, the shroud portion 4 thicker than the wing portion is heated by the proximal end portion 13b of the heating coil 13 arranged so as to meander or circulate around the shroud portion 4. As a result, a larger amount of heat is supplied to the shroud portion 4 than the thin turbine blade 2, so that the entire turbine blade 2 is uneven in temperature without causing a heating delay in the thick shroud portion 4. As a result, the blade can be prevented from being deformed or twisted, and the brazing accuracy can be increased.

Next, a third embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the component already demonstrated in said each embodiment, and description is abbreviate | omitted.
In FIG. 11, the form of the heating coil 13 installed from the blade end side of the turbine blade 2 is shown. The end portion of the turbine blade 2 is provided with a shroud portion 4 that is considerably thicker than the blade portion. However, the shroud portion 4 has a smaller thickness than the thin blade portion, and thus has a thick wall thickness. It is known that when a component whose temperature changes is heated, the time to reach the target temperature is not constant, and control is difficult. Therefore, in this embodiment, it is expected that the shroud portion 4 having a small magnetic field canceling effect will be heated and the thin blade portion is preheated by the heat (3 to 5 seconds), and the entire blade is constant regardless of the location. The heating position thickness W (2δ below) is set so that the heating coil 13 is heated to a constant temperature, and the shape of the heating coil 13 is adjusted so that the heating coil 13 is disposed there. Specifically, for example, assuming that the depth that can be heated to 700 ° C. in 3 seconds is δ, the heating coils 13 are arranged on both sides of the turbine blade 2 and up to 700 ° C. in 3 seconds without being affected by the magnetic field canceling effect. In order to heat, the thickness of the turbine blade 2 sandwiched between the heating coils 13 is desirably 2δ or more. Therefore, in consideration of the shape of the turbine blade 2, as shown in FIG. 12, the shape of the heating coil 13 is set so that the thickness of the portion sandwiched between the heating coils 13 in any portion of the blade is 2δ or more. Arrange. In addition, since there is a part which does not need to perform induction heating in the shroud part 4, the insulating plate 52 is stuck to the part so that the heating by the heating coil 13 does not occur. Thereby, there is little shift of the heating pattern due to the coil setting misbalance at the time of brazing on site, and improvement in temperature accuracy can be expected. In addition, the heating coil 13 can be easily positioned and the work can be efficiently performed.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the component already demonstrated in said each embodiment, and description is abbreviate | omitted.
When using a brazing material in the form of a sheet, the brazing material sheet is sandwiched between the groove portion of the turbine blade 2 and the stellite piece 3 and the periphery is bent and cut, but the brazing material sheet has elasticity. Therefore, spring back occurs at the bent portion, and a gap is likely to be generated between the groove portion and the stellite piece 3. Therefore, in the present embodiment, the brazing material is a powder instead of a sheet, and the stellite pieces 3 are pre-coated by screen printing and fixed. Specifically, a material in which a film having a light specific gravity such as SiO ₂ is vapor-deposited on particles of nano-size or sub-micron size brazing material is used. The formation of the SiO ₂ film is indispensable for preventing oxidation of the brazing material that causes blowholes when brazing in the atmosphere. As shown in FIG. 13, when the fine powder of the particles 70 on which the SiO ₂ film is formed is mixed with the water-soluble alcohol binder 71 and precoated on the stellite piece 3, the spring has been a problem when the brazing material sheet is used. Generation of a gap between the groove portion and the stellite piece 3 due to the back can be prevented.

Fine powder of brazing material is vapor-deposited with SiO ₂ and nano-capsuling of several μm or less is performed. When the stellite piece 3 pre-coated is placed and fixed on the groove portion of the turbine blade 2 and heated, the brazing material melts and separates into a SiO ₂ component and a metal component, and the light specific gravity SiO ₂ component is a flux. Together, it forms a slag and is discharged to the outside through the gap between the stellite piece 3 and the surface of the turbine blade 2, but the metal component adheres between the stellite piece 3 and the surface of the turbine blade 2 and has a quality. High brazing becomes possible. Thereby, it becomes easy to keep the clearance gap between the stellite piece 3 and the surface of the turbine blade 2 constant, and brazing quality can be improved. In addition, since there is no need to cut the brazing material sheet, workability can be improved.

Next, a fifth embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the component already demonstrated in said each embodiment, and description is abbreviate | omitted.
In FIG. 14, the stellite piece 3 arrange | positioned on the surface of the turbine blade 2 is shown. The stellite piece 3 of the present embodiment is divided into a plurality of pieces in the span direction of the turbine blade 2 and has a shape like a tile attached to the surface of the blade. The divided body 3a of the stellite piece 3 has a width in the span direction of about 50 mm, and as shown in FIG. 15, the divided surfaces of adjacent ones are formed obliquely or stepwise. In this way, the stellite piece 3 is formed in a plurality of tiles, fitted one by one to the groove portion, and fixed in place with a button-type restraining jig (not shown), thereby the stellite piece for the groove portion. The combination of 3 is very simple compared to the one-piece stellite piece 3. Further, it should be noted that the flux contained in the brazing material is discharged to the outside from the joint of the divided body 3 a of the stellite piece 3, and the metal component of the brazing material is between the stellite piece 3 and the surface of the turbine blade 2. Only remains, and both are fixed, so high quality brazing is possible.
The reason why the dividing surfaces of the divided bodies 3a of the stellite pieces 3 are formed obliquely or stepwise is to increase the joint area between the divided bodies 3a and increase the strength, so long as sufficient strength can be secured. You may cut it to make a right angle.

  FIG. 16 shows a modification of the present embodiment. In the stellite piece 3 of the present embodiment, a plurality of grooves 3b extending in the width direction of the blade are formed on the surface to be brazed in close contact with the surface of the turbine blade 2 so as to be separated in the span direction. The interval between the grooves 3b is about 50 mm, the width of the groove 3b itself is 1 to 2 mm, and the depth is about 1 mm. Thus, when the groove 3b is formed in the stellite piece 3, and the surface on which the groove 3b is formed is brought into close contact with the surface of the turbine blade 2 and brazed, the flux contained in the brazing material flows into the groove 3b of the stellite piece 3, Since the surface of the stellite piece 3 excluding the groove 3b is in close contact with the surface of the turbine blade 2, only the metal component of the brazing material remains in this portion and both are fixed, so that high-quality brazing is possible. Further, since the groove 3b is formed, the stellite piece 3 is easily bent, and the alignment of the stellite piece 3 with the groove portion becomes very simple.

It is a figure which shows the 1st Embodiment of this invention, Comprising: It is a figure which shows the whole structure of an induction heating apparatus. It is a figure which shows the structure of a restraint jig | tool, Comprising: (a) is the state which restrained the part with a large wing | blade width, (b) is a figure which shows the restraint state for the part with a narrow wing | blade width. It is a figure which shows the structure of the axis | shaft for clearance gap management, Comprising: It is a figure which shows the state inserted and fixed to the clearance gap of the shroud part. It is a figure which shows the structure of a branch burner. It is a figure which shows the structure of a temperature gauge. It is a figure which shows the state which attached the temperature gauge to the turbine blade. It is a graph which shows the heating pattern implemented with an induction heating apparatus. It is a figure which shows the 2nd Embodiment of this invention, Comprising: It is a figure which shows the shape of the heating coil for heating a shroud part, without delaying from another part. It is a figure which shows the modification of 2nd Embodiment, Comprising: It is a figure which shows the structure of the heating coil for heating a shroud part, without delaying from another part. It is a figure which shows another modification of 2nd Embodiment, Comprising: It is a figure which shows the structure of the heating coil for heating a shroud part, without delaying from another part. It is a figure which shows the 3rd Embodiment of this invention, Comprising: It is a figure which shows arrangement | positioning of the heating coil for heating the whole wing | blade uniformly. It is a figure which shows the positional relationship of a turbine blade and the heating coil arrange | positioned at the both sides. It is a figure which shows the 4th Embodiment of this invention, Comprising: It is a figure which shows the particulate brazing material pre-coated by the stellite piece. It is a figure which shows the 5th Embodiment of this invention, Comprising: It is a figure which shows the stellite piece affixed on the surface of the turbine blade. It is sectional drawing of the turbine blade to which the stellite piece was affixed, Comprising: (a) is what the division | segmentation surface of a stellite piece inclines, (b) is a figure which shows what the division | segmentation surface is stepped. is there. It is sectional drawing which shows the modification of 5th Embodiment, Comprising: It is a figure which shows what has the groove | channel formed in the brazing surface of a stellite piece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotor 2 Turbine blade 3 Stellite piece 10 Induction heating apparatus 13 Heating coil 14 Thermometer 20 Restraint jig 30 Gap management jig 40 Branch burner

Claims (10)

A new stellite piece is brought into close contact with the surface of the turbine blade from which the worn stellite piece has been removed, with a brazing material interposed therebetween,
Adhering the new stellite pieces to the surface of the turbine blade using a restraining jig at a plurality of locations,
While performing temperature management of the turbine blade using a thermometer installed directly on the surface of the turbine blade to which the new stellite piece is closely attached,
The surface of the turbine blade, to which the new stellite piece is closely attached, is heated by using an induction heating coil, and the new stellite piece is brazed to the turbine blade, and the stellite piece is replaced on the turbine blade surface. Method. A restraining jig used for closely attaching a stellite piece to the surface of the turbine blade with a brazing material interposed therebetween,
A front hook portion locked to a front edge of the turbine blade, a rear hook portion locked to a rear edge of the turbine blade, an intermediate portion pivotally supporting the front hook portion, and the intermediate portion An elastic member that exerts a tension that connects the portion and the rear hook portion and draws them together,
A restraining jig, wherein a pressing portion that is pressed against the stellite piece by a tension exerted by the elastic member is formed on the front hook portion. A gap management jig that is used to maintain a constant gap between two turbine blades that are implanted in a rotor and are adjacent to each other in the rotational direction.
A wedge-shaped portion inserted in a gap between a shroud portion provided at a blade tip of one turbine blade of the two turbine blades and a shroud portion provided at a blade tip of the other turbine blade; and the wedge-shaped portion Between the base portion projecting so as to form a V-shape with one side as a side, a female screw hole formed through the base portion toward the wedge-shaped portion, and the wedge-shaped portion screwed into the female screw hole. A gap management jig comprising a bolt sandwiching the shroud portion. A branch burner for heating the surface of the turbine blade,
At least a main pipe portion having a length to be heated of the turbine blade, and a plurality of burner nozzles provided in the main pipe portion so as to be separated from each other in the length direction;
The branch burner characterized in that the plurality of burner nozzles can change the amount of protrusion from the main pipe portion and the injection direction of the flame in accordance with the surface shape of the opposed turbine blades. A stellite piece is brought into close contact with the surface of the turbine blade with a brazing material interposed therebetween, and the turbine wing having the stellite piece brought into close contact is heated using an induction heating coil disposed along the turbine blade, A method for attaching stellite on the surface of a turbine blade for brazing the stellite piece,
The amount of heat generated in the portion adjacent to each part of the induction heating coil is set in proportion to the thickness of each part of the turbine blade. Method. A stellite piece is brought into close contact with the surface of the turbine blade with a brazing material interposed therebetween, and the turbine blade with the stellite piece brought into close contact is heated using an induction heating coil arranged so as to sandwich the turbine blade, and the turbine blade A method for attaching stellite on the surface of a turbine blade to braze the stellite piece to
A method of attaching a stellite piece on a surface of a turbine blade, wherein the thickness of the portion of the turbine blade sandwiched between the heating coils is set to a thickness that is not affected by the magnetic field canceling effect of the induction heating coil. A stellite piece is brought into close contact with the surface of the turbine blade with a brazing material interposed therebetween, and the turbine wing having the stellite piece brought into close contact is heated using an induction heating coil disposed along the turbine blade, A method for attaching stellite on the surface of a turbine blade for brazing the stellite piece,
A brazing material is formed into particles, and a brazing material in which an oxide film is formed on the surface of each particle is mixed with a binder and applied to the surface of the stellite piece to form a coating of brazing material, on the surface of the turbine blade, A method for attaching a stellite piece on a surface of a turbine blade, wherein the stellite piece is brought into close contact with the film interposed therebetween.   A brazing material characterized by being formed into particles and having an oxide film formed on the surface of each particle. A stellite piece is brought into close contact with the surface of the turbine blade with a brazing material interposed therebetween, and the turbine wing having the stellite piece brought into close contact is heated using an induction heating coil disposed along the turbine blade, A method for attaching stellite on the surface of a turbine blade for brazing the stellite piece,
A method of attaching a stellite piece to a surface of a turbine blade, wherein the stellite piece is divided into a plurality of pieces and the divided pieces are arranged on the surface of the turbine blade without a gap therebetween. A stellite piece is brought into close contact with the surface of the turbine blade with a brazing material interposed therebetween, and the turbine wing having the stellite piece brought into close contact is heated using an induction heating coil disposed along the turbine blade, A method for attaching stellite on the surface of a turbine blade for brazing the stellite piece,
A method for attaching a stellite piece on a surface of a turbine blade, wherein a groove is formed in a brazing surface of the stellite piece.

Images