RU2586191C1 - Method for recovery of retaining blades of turbomachinery shelves of titanium alloys - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention can be used in repair of worn-out or damaged platforms of turbomachine blades made from titanium alloys. Method comprises removing from damaged areas coating and surface layer of metal, for example, by diamond grinding. Method includes surfacing damaged areas of titanium α-alloy or quasi-α-alloy and machining surfaced areas until restoration of preset geometrical sizes and shapes thereof. To preserve initial base size platforms, surfacing and machining are first carried out on platform on one side of blade and then on platform on other side of blade. After annealing of blades in vacuum at temperature not higher than 650 °C wear-resistant coating is applied on recovered areas by, for example, detonation spraying.

EFFECT: method provides high accuracy of restoration of geometrical dimensions and shape of platforms, as well as high quality of repair, which increases reliability and service life of repaired blades.

3 cl, 2 dwg

Description

The invention relates to the field of welding and surfacing and can be used in the repair of worn or damaged retaining shelves of the blades of turbomachines made of titanium alloys.

There is a method of surfacing when restoring worn blades of turbomachines, including fusing alloy blades of metal onto the blades, machining to ensure the specified geometry of the blades, subsequent heat treatment and applying a protective coating (RU 2434973 C2, C23C 26/00, B23K 9/04, 11/27/2011 ) The disadvantage of this method is the inability to use it to restore the retaining shelves of the blades.

There is also a method of repair surfacing of worn or damaged shelves of turbomachine blades, adopted as a prototype and includes removing from damaged sections of the coating and surface layer, surfacing of damaged sections, machining the deposited sections to restore the specified geometric dimensions and shapes, heat treatment of the blades in vacuum and applying a wear-resistant coating to restored sites (US 20080028605 A1, B23P 6/00, 02/07/2008). The disadvantage of this method is the low reliability and low life of the blades.

The task of the invention is to increase the reliability and service life of the blades.

The technical result obtained in this case is to ensure high accuracy of restoration of the geometric dimensions and shape of the retaining shelves of the blades, as well as obtaining high quality deposited sections.

The solution to this problem is achieved by the fact that in the method of restoring the shroud shelves of the blades of turbomachines made of titanium alloys, including removing from the damaged sections of the coating and the surface layer, surfacing the damaged sections in a neutral gas or vacuum, and machining the deposited sections until the specified geometric dimensions and shapes are restored first carry out on the retaining shelf on one side of the scapula, and then on the retaining shelf on the other side of the scapula, moreover, as a fused mat Rial use a titanium α-alloy or quasi-α-alloy, after which the blades are annealed at a temperature not exceeding 650 ° C and a vacuum of 10 ^-3 ... 10 ^-4 mm Hg and applying a wear-resistant coating to the restored areas by spraying.

The removal of the coating and the surface layer of the material is carried out, for example, by diamond grinding, and the application of a wear-resistant coating is carried out, for example, by detonation spraying.

The invention is illustrated by drawings, which show:

in FIG. 1 is a general view of a repair blade with surfacing of a defective portion of the retaining shelf,

in FIG. 2 - general view of the blade with restored retaining shelves.

The method is implemented as follows.

From the repaired (defective) sections 1 of the retaining shelves 2 of the blade 3 made of a titanium alloy, the protective coating and the surface layer of the material of the blade are removed, especially in cases of cracks in the coating that can pass into the main material of the blade. This operation is carried out, for example, by diamond grinding. After that, the repaired sections 1 are cleaned of dust and degreased. The actual dimensions of the retaining shelves 2 are monitored in order to determine the size of the deposited material 4. To preserve the initial basic size “H” of the retaining shelves 2, the surfacing of material 4, which is used as a titanium α-alloy or quasi-α-alloy, is performed to eliminate the effect oxygen to the material of the blade in a neutral gas medium (for example, argon, helium) or in vacuum, first on the retaining shelf 2 on one side of the blade 3, while the blade is based and fixed in the corresponding devices 5 (according to azans conditionally). After surfacing the material 4 on one of the retaining shelves 2, without releasing the blade from the fixtures 5, the deposited portion is machined to remove excess deposited material 4 and restore the specified geometric dimensions and shape of the retaining shelf. The specified processing can be carried out, for example, by milling and subsequent diamond grinding.

Then the blade 3 is turned over and fixed in the devices 5 by the already repaired retaining shelf 2, after which the surfacing of the material 4 and the machining of the deposited section are carried out similarly until the specified geometric dimensions and shape of the second retaining shelf are restored. To relieve residual stresses after surfacing and machining, the blades are annealed in vacuum (10 ^-3 ... 10 ^-4 mm Hg) at a temperature not exceeding 650 ° C. The indicated temperature is due to the need to avoid grain growth of the structure of the material of the blade and the deterioration of its mechanical properties, and the amount of vacuum in the vacuum chamber where the annealing is performed is determined in order to prevent the formation of an oxide film on the surface of the retaining shelves and deterioration of adhesion during subsequent application of a wear-resistant coating on them .

The choice of material deposited on damaged sections in the form of titanium α-alloys or quasi-α-alloys is due to the absence of phase transformations in them during heat treatment, which, when exposed to a thermal factor, allows them to maintain a stable structure of the material without hardening.

After the specified heat treatment is carried out, a wear-resistant coating is applied to the repaired retaining shelves by, for example, detonation spraying, which ensures a minimum thermal exposure time for the blade. In conclusion, if necessary, quality control of the repaired areas, for example capillary LUM-control, can be carried out.

The use of this method of restoring the retaining shelves of the blades provides an increase in the reliability and service life of the blades, while achieving high accuracy in restoring the geometric dimensions and shape of the retaining shelves, and also provides high quality repairs.

Claims (3)

1. A method of restoring the retaining shelves of blades of turbomachines made of titanium alloys, including removing from damaged areas of the coating and surface layer, surfacing the damaged areas in a neutral gas medium or in vacuum, and machining the deposited areas to restore the specified geometric dimensions and shapes, which are first carried out on the retaining a shelf on one side of the scapula, and then on a retaining shelf on the other side of the scapula, moreover, a titanium α-alloy or quasi-α-alloy, after which the blades are annealed at a temperature of no higher than 650 ° C and a vacuum of 10 ^-3 ... 10 ^-4 mm Hg and applying a wear-resistant coating to the restored areas by spraying. 2. The method according to p. 1, characterized in that the removal of the coating and the surface layer of the material is carried out by diamond grinding. 3. The method according to p. 1, characterized in that the application of a wear-resistant coating is carried out by detonation spraying.

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