EP2125292B1 - Method and device for the surface peening of a partial element of a component of a gas turbine - Google Patents

Abstract

A method and device for the surface peening, especially ultrasonic shot-peening, of at least one partial element of a component of a gas turbine, is disclosed. The partial element, e.g., a sealing fin, and at least one surface of a vibration device impinging the blasting material are positioned relative to each other at an angle between 70° and 90° based on the direction of extension of the sealing fin.

Description

The invention relates to a method and a device for surface blasting, in particular for ultrasonic shot peening at least one sub-element of a component, in particular a blisk of a gas turbine of the kind specified in the preambles of claims 1 and 9 respectively.

Such a method and such a device are for example already in the EP 1 101 568 B1 as known, wherein the rotor blades of a rotor designed as a blisk are shot peened to improve their fatigue strength. For this purpose, the rotor is positioned in a holding device, so that it is rotatably supported about its axis of rotation. By rotating the rotor whose rotor blades are guided through a blasting chamber, on the underside of a vibration device in the form of an ultrasonic sonotrode is arranged with an at least approximately horizontally extending oscillating surface. The blasting chamber is thereby bounded both axially - ie in the region of the broad sides of the rotor - as well as radially - ie in the field of rotor blades - the blisk by corresponding chamber walls.

document EP 1623794 shows a method and an apparatus according to the preamble of claims 1 and 7.

One problem of such processes known today for surface blasting of rotors is that there is a risk of deformation or distortion due to surface blasting, especially in the case of thin-walled subelements. For this reason, it is common today to protect such sub-elements in particular by means of a cover. Since such thin-walled sub-elements, for example a blisk, often lie in a joining region with an adjacent blisk, this covering can lead to an insufficient hardening of the joining regions. In addition, there is the further problem that the sub-element itself also can not be solidified.

Object of the present invention is therefore to provide a method and an apparatus of the type mentioned, with which previously not to be processed sub-elements of the component of the gas turbine without the risk of deformation or distortion can be processed by surface blasting.

This object is achieved by a method and an apparatus having the features of claims 1 and 7, respectively. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the respective dependent claims.

In the method according to the invention, it is provided that the surface of the at least one vibration device and a thin-walled Dichtfin relative to its extension direction at an angle between 70 ° and 90 ° are positioned relative to each other. In other words, it is provided according to the invention, the hitherto in the surface blasting of a rotor, in particular a blisk, not editable without deformation or distortion thin-walled Dichtfin process that the surface of the at least one vibration device is arranged in relation to the Dichtfin in the specified angular range. By this appropriate arrangement of the surface of the vibrating device relative to the Dichtfin is achieved that its broadsides can be processed synchronously with blasting material during the blasting process. Since the sealing fin is thus subjected to blasting material on both sides in the same way, deformation or even bending away of the usually a few millimeters thick and high partial elements under the influence of the ball hanger is avoided. On the other hand, the end face or tip of the respective sealing fin, which comes into contact with an inlet or squirting lining during operation of the engine, is solidified in an optimum manner. As a result, the abrasion hardness and the life of the end face or tip of the sealing fin increase considerably.

Another advantage is that the joining zones of the rotor or the blisk, which are often arranged in the region of the thin-walled sealing fins, can be effectively consolidated so that the tensile residual stresses in the heat-affected zone of the joint can be converted near the surface into compressive stresses. In an optionally slightly oblique arrangement of the surface of the at least one vibration device with respect to the direction of extension of the sealing fins can be achieved that the web neck - ie the transition region between the Dichtfin and a supporting outer circumferential wall of the rotor - is solidified.

In a particularly advantageous embodiment, the surface of the at least one vibration device and the sealing fin are positioned relative to one another with respect to its extension direction at an angle between 85 ° and 90 °, and in particular at least approximately perpendicularly. In other words, the surface of the at least one vibration device is preferably positioned at least approximately perpendicular relative to the sealing finger to be processed, so that a particularly uniform and synchronous radiation of the two broad sides of the sealing fin results and deformation or bending away of the sealing finger is impossible.

A particularly uniform and reproducible solidification of the respective sealing fins can be achieved if it is processed in a blasting chamber comprising the associated vibration device. Through the blasting chamber can be achieved in a simple manner a constant amount of blasting and thus a uniform and uniform jet result.

If the boundary walls of the blasting chamber are arranged substantially parallel to this with respect to the direction of extension of the sealing fin, this has the advantage that a particularly synchronous and uniform radiation of the two broad sides can be achieved.

In a further embodiment of the invention, a plurality of sealing fins are processed in a common blasting chamber. This results in a process optimized with regard to the processing time.

The advantages described in relation to the method according to the invention apply identically also to the device according to the invention.

It has been found in the device to be particularly advantageous when a blasting chamber is equipped with boundary walls, which divide as partitions two adjoining blast chambers from each other. As a result, the partitions can fulfill a dual function as a respective boundary wall, wherein the two adjacent jet chambers can be arranged in close proximity to each other.

As further advantageous, it has been shown when the blasting chamber is provided with chamber walls which are at least partially flexible. As a result, the device according to the invention can also be used with different components with differing geometry.

Finally, it has proven to be advantageous if a distribution device is preferably provided within the blasting chamber, with which the blasting material can be distributed over the surface of the at least one vibration device. The vibration device is preferably arranged correspondingly at a lowest point of the surfaces of the vibration devices, so that blasting material collecting there is uniformly distributed or also positioned in upper regions of the surfaces. Overall, it is thus achieved that over the entire surfaces a uniform amount of blasting material is present, so that an extremely uniform solidification of the sealing fins can be realized.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing.

This shows a schematic sectional view of a rotor of a gas turbine in the form of a blisk, which in the present case comprises two stages and in the region of a peripheral wall a plurality of outer circumferential circumferential thin-walled sealing fins, in the region respectively associated jet chambers each with associated vibration devices are provided, whose respective surfaces are positioned relative to the associated Dichtfin relative to the direction of extension at an angle of substantially 90 °.

From a rotatable rotor of a gas turbine in the form of a blisk 10, which is shown in a schematic and axial sectional view, two stages can be discerned here, to which a first and a second disk 12, 14 and a ring of first and second rotor blades 16, 18 are assigned. Of each of the discs 12, 14, a substantially outer-peripheral-side platform 20, shown in the form of a line, can be seen, to which in each case a sub-platform region 22 connects radially inwards. Each of the two sub-deck regions 22 merges radially inwardly into a respective disk neck 24 that connects the associated sub-platform region 22 to a disk body 26. The radially inner end of the respective disk body 26 is formed by an associated hub 28, which is a counterweight to the respective rotor blades 16, 18. The two disks 12, 14 are connected via a peripheral wall 30, which is rotationally symmetrical about an axis of rotation R of the blisk 10 and extends on one side up to a wing 32 and on the other side up to a flange 34.

Outer peripheral side of the peripheral wall 30, the present Blisk 10 comprises five thin-walled Dichtfins 36 formed as sub-elements, which protrude radially circumferentially approximately perpendicular with respect to the rotation axis R of the blisk 10 of the peripheral wall 30 to the outside. These thin-walled sealing fins 36 are also generally called "fin sealing lips" or "sealing webs" and have, for example, a radial height of 3 mm and a thickness of 2 mm. The sealing fins 36 serve to cooperate with an inlet or scraper lining, not shown, which rotates on the inside circumference of turbine-resistant guide vanes (also not shown) in a ring around the respectively associated sealing finger 36.

In order to consolidate the sealing fins 36 by surface blasting by means of a blasting material, in particular in the form of spheres, in the present case there are a total of three blasting chambers 38, 40, 42 provided, which are bounded by respective boundary walls or dividing walls 44, 45, 46, 47, 48, 49 or divided from each other. In addition to the three jet chambers 38, 40, 42 assigned to the respective sealing fins 36, two further jet chambers 50 are provided, within which the rotor blades 16, 18 can be solidified by means of surface jets. In addition to the boundary walls or dividing walls 44, 45, 46, 47, 48, 49, the blasting chambers 38, 40, 42 are also assigned end walls 52, which may optionally have corresponding recesses in the area of the sealing fins 36.

From the figure it can be seen that the four central boundary or partition walls 45, 46, 47, 48 are each sealed against the associated platform 20 of the rotor blades 16, 18. In this way, a loss or a transfer of blasting material from one to the other blasting chamber 3 8, 40, 42 and 50 are prevented. Between the respective boundary or partition wall 45, 46, 47, 48 and the associated platform 20 can be arranged corresponding sealing means. Alternatively or additionally, the gap or the distance between the respective boundary or partition wall 45, 46, 47, 48 and the associated platform 20 is selected so that the blasting material can not pass between them. The outer boundary or partition walls 44 and 49 are arranged sealed relative to the peripheral wall 30 in a corresponding manner. In addition, the boundary or partition walls 44, 45, 46, 47, 48, 49 may also be designed to be flexible in order to achieve an adaptation to components or rotors with different geometries.

On the side opposite the sealing fins 36 side of the associated blasting chamber 38, 40, 42 each have a surface 54 of an associated vibration device 56 is provided, which in the present case as an ultrasonic sonotrode not shown and is assigned as an end boundary wall of the respective blasting chamber 38, 40, 42 , By means of the respective ultrasonic sonotrode, the respective surface 54 of the vibration device 56 is caused to oscillate, as a result of which the grit-which in the present case is in the form of a sphere-is accelerated for shot peening. In the present exemplary embodiment, one and the same vibration device 56 is used for all the jet chambers 38, 40, 42-that is to say also for the jet chambers 50 of the rotor blades 16, 18 the respective blasting chamber 38, 40, 42 and 50 associated vibrating or the blasting material acting surface 54 respectively by the boundary or partition walls 44, 45, 46, 47, 48, 49 are divided. As included in the scope of the invention, however, it should be considered that each of the blasting chambers 38, 40, 42 may also have a separate vibration device 56.

Each of the sealing fins 36 comprises two broad sides 58, 60, which are annular in plan view, and a rounded, narrow end face 62. Furthermore, it can be seen that each sealing finger 36 comprises a web neck 64, in which the circumferential wall 30 merges into the sealing finger 36. Optionally, the Dichtfin 36 - as can be seen in particular from Fig. 1 - taper towards the outer peripheral side, with the respective individual faces of each of the two broad sides 58, 60 extend substantially plane-parallel to each other. In this case, a radial extension direction is shown on one of the sealing fins 36 with the dot-dash line E (blasting chamber 38). In this case, this extension direction E is essentially identical for all sealing fins 36.

So that the sealing fins 36 are not deformed or bent or otherwise distorted during shot peening, the surfaces 54 of the respective sealing fins 36 associated vibration means 56 relative to the radial direction of extension E of the corresponding sealing fins 36 at an angle α between 70 ° and 90 ° relative to each other positioned. In the present exemplary embodiment, this angle α is at least approximately 90 °, since in this way a particularly uniform radiation of both broad sides 58, 60 of the respective sealing finger 36 can be realized. This resulting particularly advantageous solidification of the two broad sides 58, 60 turns in particular also when the angle α is between 85 ° and 90 °. Accordingly, in the present embodiment, each of the surfaces 54 of the associated vibrator 56 and a respective surface normal O (blasting chamber 42) of the respective broad side 58, 60 of the corresponding sealing finger 36 are substantially at least approximately parallel relative to one another. By means of the surface 54 of the vibration device 56 thus the two opposite broad sides 58, 60 of the sealing fins 36 are surface blasted synchronously. The boundary or partition walls 44, 45, 46, 47, 48, 49 of the jet chambers 38, 40, 42 extend in this case substantially parallel to the extension direction E of the respective sealing web 36 or parallel to their respective broad sides 58, 60. If - as explained above - the surface 54 is not arranged at least approximately perpendicular to the radial extension direction of the sealing finger 36, but the angle α is between 70 ° and 90 °, so each of the boundary walls or partitions 44, 45, 46, 47, 48, 49 relative to the respective surface normal O course, in a correlating angle.

The relative arrangement of the sealing fins 36 with respect to the corresponding surfaces 54 of the associated vibration device 56 can either be done by positioning the respective blasting chamber 38, 40, 42 correspondingly opposite the blisk 10, or vice versa, that the blisk 10 corresponding to the respective blasting chamber 38, 40, 42 is arranged. In the latter case, as shown here, a retaining device 66 can be provided, by means of which the blisk 10 can be arranged opposite the blasting chamber 38, 40, 42. The holding device 66 includes, for example, in the figure, only schematically indicated bearing blocks 68 through which the blisk 10 is rotatably mounted about its axis of rotation R. Thus, each of the sealing fins 36 can be circumferentially solidified or blasted in one process step. However, the relative positioning of the sealing fins 36 and the surfaces 54 can also be made by the chamber walls 44, 45, 46, 47, 48, 49 of the respective blasting chamber 38, 40, 42 serving as stops against the peripheral wall 30 of the blisk 10.

Thus, the blasting material is not excessive at a lowest point of the associated blasting chamber 38, 40, 42 collects, but rather evenly distributed over the respective surfaces 54 is - for example - in the lower part of the blasting chamber 42, a distribution device 70 is provided, which also has a vibrating Surface 72 includes. The distribution device 72 can also be designed as an ultrasonic sonotrode. Likewise, other configurations such as, for example, a compressed-air device would also be conceivable, with which a homogeneous distribution of the blasting material over the respective surfaces 54 can be realized.

As included in the scope of the invention, it should be considered that the apparatus described here or the associated method can be applied not only to a blisk 10, but of course also to other components of gas turbines.

Claims (12)

1. Method for surface-peening, in particular ultrasonic shot-peening, of at least one partial element (36) of a component (10) of a gas turbine, in which the partial element (36) and at least a surface (54) of a vibration device (56) impinging the peening material are positioned relative to each other, wherein the surface (54) of the at least one vibration device (56) and a sealing fin (36) are positioned with reference to the latter's direction of extension (E) at an angle (α) between 70° and 90° relative to each other, wherein the at least one sealing fin (36) is processed in at least a first peening chamber (38, 40, 42) containing the associated vibration device (56), boundary or dividing walls (44, 45, 46, 47, 48, 49) of the peening chamber (38, 40, 42) are arranged with reference to the direction of extension (E) of the sealing fin (36) so as to be substantially parallel to the fin,
   characterised in that
   a rotor blade (16, 18) of the component (10) is arranged in at least a second peening chamber (50) delimited by the dividing walls (45, 46).
2. Method according to claim 1, characterised in that the surface (54) of the at least one vibration device (56) and the sealing fin (36) are positioned with reference to the latter's direction of extension (E) at an angle (α) between 85° and 90°, and in particular at least approximately perpendicularly, relative to each other.
3. Method according to claim 1 and 2, characterised in that two opposing broad sides (58, 60) of the sealing fin (36) are surface-peened synchronously by means of the surface (54) of the at least one vibration device (56).
4. Method according to claim 1, characterised in that a plurality of sealing fins (36) is processed in a common peening chamber (38, 40, 42).
5. Method according to one of the preceding claims, characterised in that in order to surface-peen the sealing fin (36) the component (10) is rotated about its rotational axis (R).
6. Method according to one of the preceding claims, characterised in that the component (10) is arranged by means of a holding device (66) relative to the surface (54) of the at least one vibration device (56).
7. A device for surface-peening, in particular ultrasonic shot-peening, at least one partial element (36) of a component (10) of a gas turbine, having at least one vibration device (56) which comprises a surface (54) impinging the peening material, and having a holding device (66) by means of which the partial element (36) and the surface (54) of the vibration device (56) can be positioned relative to each other, wherein by means of the holding device (66) the surface (54) of the at least one vibration device (56) and a sealing fin (36) can be positioned with reference to the latter's direction of extension (E) at an angle (α) between 70° and 90° relative to each other, wherein associated with the at least one vibration device (56) there is at least a first peening chamber (38, 40, 42) in which the at least one sealing fin (36) can be processed, with boundary or dividing walls (44, 45, 46, 47, 48, 49) of the peening chamber (38, 40, 42) being arranged with reference to the surface (54) of the vibration device (56) so as to be substantially perpendicular thereto, characterised in that there is at least a second peening chamber (50) which is delimited by the dividing walls (45, 46) and in which at least one rotor blade (16, 18) can be processed.
8. A device according to claim 7, characterised in that by means of the holding device (66) the surface (54) of the at least one vibration device (56) and the sealing fin (36) can be positioned with reference to the latter's direction of extension (E) at an angle (α) between 85° and 90°, and in particular at least approximately perpendicularly, relative to each other.
9. A device according to claim 7 or 8, characterised in that boundary walls of the peening chamber (38, 40, 42) are formed as dividing walls (45, 46, 47, 48).
10. A device according to one of claims 7 to 9, characterised in that one and the same vibration device (56) is provided for a plurality of peening chambers (38, 40, 42).
11. A device according to one of claims 7 to 10, characterised in that boundary or dividing walls (44, 45, 46, 47, 48, 49) of the peening chamber (38, 40, 42) are formed so as to be flexible at least in regions.
12. A device according to one of claims 7 to 11, characterised in that a distributing device (70) is provided with which the peening material can be distributed over the surface (54) of the at least one vibration device (56).

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