CN109055883B

CN109055883B - Method for locally plasma-spraying NiCrAlY coating on inner wall of aluminum alloy casing with boss and application

Info

Publication number: CN109055883B
Application number: CN201811255421.3A
Authority: CN
Inventors: 徐丽萍; 邓春明; 牛少鹏; 陈龙飞; 宋进兵; 邓畅光; 刘敏; 周克崧
Original assignee: Guangdong Institute of New Materials
Current assignee: Institute of New Materials of Guangdong Academy of Sciences
Priority date: 2018-10-25
Filing date: 2018-10-25
Publication date: 2021-03-02
Anticipated expiration: 2038-10-25
Also published as: CN109055883A

Abstract

The invention relates to a method for locally plasma-spraying a NiCrAlY coating on the inner wall of an aluminum alloy casing with a boss and application thereof, belonging to the technical field of material surface treatment. A method for locally plasma-spraying a NiCrAlY coating on the inner wall of an aluminum alloy casing with a boss comprises the following steps: the method comprises the following steps of carrying out dust removal and oil removal treatment on a cartridge receiver, then protecting a non-spraying area, carrying out surface sanding and roughening treatment on an area to be sprayed, putting the cartridge receiver into a fixture and fixing the cartridge receiver on a rotary table, and spraying a NiCrAlY coating on the area to be sprayed. In the spraying process, when the temperature of the area to be sprayed exceeds 150 ℃, the spraying is stopped, and when the temperature is reduced to be below 100 ℃, the spraying is continued, and the steps are repeated until the thickness meets the requirement. The method ensures the temperature control in the spraying process and effectively controls the deformation degree of the casing. The coating machine box prepared by the invention can reach the index of stable operation when assembled on an aeroengine, thereby having wide application prospect.

Description

Method for locally plasma-spraying NiCrAlY coating on inner wall of aluminum alloy casing with boss and application

Technical Field

The invention relates to the technical field of material surface treatment, in particular to a method for locally plasma-spraying a NiCrAlY coating on an inner wall of an aluminum alloy casing with a boss and application thereof.

Background

The power, thrust and efficiency of an engine are directly related to the sealing between rotating and stationary parts of the engine. The casing is an important fixed part in an engine, and a protective coating with the performances of wear resistance, erosion resistance, oxidation resistance, sealing and the like is generally prepared in the casing according to the requirement. The parts such as the casing have the characteristics of thin wall thickness, poor rigidity and the like, and deformation and residual stress are easy to generate in the process of preparing the coating by thermal spraying. Particularly, for the aluminum alloy casing with a large thermal expansion system, a boss on the inner wall and a protective coating only in a local area below the boss, the coating is more difficult to prepare, the coating has low percent of pass, and no mature process can be used for reference. In addition, the protective coating is typically machined to a suitable size and surface roughness to match the rotating component, so the coating must be of a thickness that provides some machining margin. The coating position processing usually has high risks, such as local shedding and local loosening of the coating in the processing process, so that the coating needs to be completely removed, and then the spraying coating is carried out again and the processing is carried out again. To ensure that the coating is completely removed, it is inevitable to remove a small portion of the substrate. Thus, re-spraying the coating requires an increase in the thickness of the coating. With the increase of the thickness of the coating, the residual stress in the coating is more concentrated, and the difficulty of preparing qualified coatings is invisibly improved. For the reasons, it is needed to develop a protective coating meeting the requirements of subsequent processing and use for the inner wall of the casing, which has a boss on the inner wall and only needs to prepare the coating in the local area below the boss, and a preparation method thereof.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide the method for locally plasma-spraying the NiCrAlY coating on the inner wall of the aluminum alloy casing with the boss, which has the advantages of high yield, low cost and environmental friendliness.

The invention also aims to provide the application of the method for locally plasma-spraying the NiCrAlY coating on the inner wall of the aluminum alloy casing with the boss in the manufacturing of an aeroengine.

The technical problem to be solved by the invention is realized by adopting the following technical scheme.

The invention provides a method for locally plasma-spraying a NiCrAlY coating on the inner wall of an aluminum alloy casing with a boss, which comprises the following steps: the method comprises the following steps of carrying out dust removal and oil removal treatment on a cartridge receiver, then protecting a non-spraying area, carrying out surface sanding and roughening treatment on an area to be sprayed, putting the cartridge receiver into a fixture and fixing the cartridge receiver on a rotary table, and spraying a NiCrAlY coating on the area to be sprayed.

In the spraying process, when the temperature of the area to be sprayed exceeds 150 ℃, the spraying is stopped, and when the temperature is reduced to be below 100 ℃, the spraying is continued, and the steps are repeated until the thickness meets the requirement.

The invention provides an application of the method for locally plasma-spraying the NiCrAlY coating on the inner wall of the aluminum alloy casing with the boss in the manufacturing of an aeroengine.

The beneficial effects of the invention include:

the invention well ensures the temperature control in the spraying process, effectively controls the deformation degree of the casing, ensures the coating quality of the transition position between the lug boss and the area to be sprayed by adjusting the sanding process parameters and the spraying parameters, has high coating processing yield and meets the operation requirement. The coating obtained by spraying can play a role in sealing, has better oxidation resistance, and the performance index of the coating meets the service working condition of the casing.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic cross-sectional view of an inner wall of an aluminum alloy casing according to the present invention;

FIG. 2 is a coating area of the inner wall of the aluminum alloy casing according to the present invention;

FIG. 3 is a microstructure of a coating provided in example 1 of the present invention;

FIG. 4 is a microstructure of a coating provided in example 2 of the present invention;

FIG. 5 is a microstructure of a coating provided in example 3 of the present invention;

FIG. 6 is a microstructure of a coating provided in example 4 of the present invention;

fig. 7 is a microstructure of a coating provided in example 5 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The following describes a method and application of plasma spraying a NiCrAlY coating on the inner wall with a boss of an aluminum alloy casing in an embodiment of the invention.

The embodiment of the invention provides a method for locally plasma-spraying a NiCrAlY coating on the inner wall of an aluminum alloy casing with a boss, which comprises the following steps: the method comprises the following steps of carrying out dust removal and oil removal treatment on a cartridge receiver, then protecting a non-spraying area, carrying out surface sanding and roughening treatment on an area to be sprayed, putting the cartridge receiver into a fixture and fixing the cartridge receiver on a rotary table, and spraying a NiCrAlY coating on the area to be sprayed.

Specifically, the surface of the casing is subjected to dust removal and oil removal treatment. The dust and oil removing treatment of the invention is a general technique in the technical field, and the invention does not limit the technique.

And protecting the non-spraying area of the casing by using a special high-temperature-resistant adhesive tape and a special metal protection tool to prevent the non-spraying area from being sprayed with a coating.

And carrying out surface sanding and coarsening treatment on the area to be sprayed. Wherein the sanding pressure is 0.2 MPa-0.4 MPa, the sanding distance is 100-150 mm, and the sanding angle is 35-60 degrees. Further, in the preferred embodiment of the invention, the sanding pressure is 0.3MPa to 0.35MPa, the sanding distance is 120mm to 130mm, and the sanding angle is 45 degrees to 50 degrees. After the sanding treatment, the compressed air is used for blowing off the sand grains or dust which possibly remains. The surface roughness Ra of the area to be sprayed after sanding treatment is more than 3 mu m.

The sand material subjected to sanding and coarsening treatment comprises at least one of white corundum, brown corundum and zirconium corundum. Preferably, the grit material has a size of 24# to 46#, wherein the grit material may have a size of 30#, 35#, 40#, 45 #.

And placing the sanded casing into a fixture, fixing the fixture on a rotary table, and spraying. The spraying powder adopted by the invention is NiCrAlY powder with the granularity of minus 105+53 mu m. The spraying process parameters are as follows: the current is 600-640A, the voltage is 80-84V, the argon gas is 63-67L/min, the hydrogen gas is 12-16L/min, the powder delivery amount is 35-45 g/min, the spraying distance is 135-145 mm, the carrier gas is 2.0-7.0L/min, the spraying angle is 45-55 degrees, and the rotating speed of the rotary table is 270-350 rpm. Preferably, the current can be 610A, 620A, 630A and 640A, the voltage can be 81V, 82V and 83V, the argon can be 64L/min, 65L/min and 66L/min, the hydrogen can be 14L/min and 15L/min, the powder feeding amount can be 38g/min, 40g/min and 42g/min, the spraying distance can be 138mm, 142mm and 144mm, the carrier gas can be 3.0L/min, 4.0L/min, 5.0L/min and 6.0L/min, the spraying angle can be 50 degrees, and the rotating speed of the rotary table can be 280rpm, 290rpm, 300rpm, 310rpm and 330 rpm.

In order to ensure the quality of the coating, the temperature is controlled in the spraying process. Air cooling is adopted in the spraying process, and the inner hole and the outer wall to be sprayed are cooled so that the temperature of the matrix is not more than 200 ℃. And in the process of moving the spray gun from the original position to the spraying starting position, the spraying area is ensured not to be sprayed. And stopping spraying when the temperature of the area to be sprayed exceeds 150 ℃, continuing spraying when the temperature is reduced to be below 100 ℃, and repeating the steps until the thickness meets the requirement.

The method ensures the temperature control in the spraying process, effectively controls the deformation degree of the casing, ensures the coating quality of the transition position between the lug boss and the area to be sprayed by adjusting the sanding process parameters and the spraying parameters, has high coating processing yield and meets the operation requirement. The coating obtained by spraying can play a sealing role, has better oxidation resistance, has the performance index meeting the service working condition of the casing, and can be used for manufacturing the field of aeroengines.

The features and properties of the present invention are described in further detail below with reference to examples.

Example 1

The embodiment provides a method for locally plasma-spraying a NiCrAlY coating on the inner wall of an aluminum alloy casing with a boss, which comprises the following steps:

step 1: and carrying out dust removal and oil removal treatment on the surface of the casing.

Step 2: and protecting the non-spraying part of the casing by using a special metal protection tool, and measuring the original inner diameter of the area to be sprayed.

And step 3: and sanding the area to be sprayed by using No. 24 zirconium corundum, wherein the sanding pressure is 0.35MPa, the sanding distance is 130mm, the sanding angle is 40 degrees, and after sanding, the compressed air is used for blowing off possible residual sand grains or dust.

And 4, step 4: and placing the sanded casing into a fixture and horizontally fixing the casing on a rotary table. And (3) installing, adjusting and fixing the positions of the cooling air pipes, wherein 2 air pipes are used, one air pipe is used for cooling the area to be sprayed on the inner wall of the casing, and the other air pipe is used for cooling the outer wall of the casing.

And 5: plasma spraying of a NiCrAlY coating is carried out on a region to be sprayed, and the specific parameters are as follows: the current is 630A, the voltage is 82V, the argon gas is 65L/min, the hydrogen gas is 14L/min, the powder feeding amount is 40g/min, the spraying distance is 140mm, the carrier gas is 3.5L/min, the spraying angle is 50 degrees, the rotating speed of the rotary table is 300rpm, and the spraying is carried out until the thickness of the coating meets the requirement.

Example 2

And step 3: and sanding the area to be sprayed by using No. 24 zirconium corundum, wherein the sanding pressure is 0.20MPa, the sanding distance is 100mm, the sanding angle is 35 degrees, and after sanding, possible residual sand grains or dust are blown off by using compressed air.

And 5: plasma spraying of a NiCrAlY coating is carried out on a region to be sprayed, and the specific parameters are as follows: the current is 640A, the voltage is 83V, the argon gas is 66L/min, the hydrogen gas is 13L/min, the powder feeding amount is 35g/min, the spraying distance is 130mm, the carrier gas is 3.5L/min, the spraying angle is 50 degrees, the rotating speed of the rotary table is 290rpm, and the spraying is carried out until the thickness of the coating meets the requirement.

Example 3

And step 3: and sanding the area to be sprayed by using No. 24 zirconium corundum, wherein the sanding pressure is 0.30MPa, the sanding distance is 150mm, the sanding angle is 60 degrees, and after sanding, the compressed air is used for blowing off possible residual sand grains or dust.

And 5: plasma spraying of a NiCrAlY coating is carried out on a region to be sprayed, and the specific parameters are as follows: the current is 600A, the voltage is 84V, the argon gas is 63L/min, the hydrogen gas is 15L/min, the powder feeding amount is 45g/min, the spraying distance is 145mm, the carrier gas is 5.0L/min, the spraying angle is 55 degrees, the rotating speed of the rotary table is 320rpm, and the spraying is carried out until the thickness of the coating meets the requirement.

Example 4

And step 3: and sanding the area to be sprayed by using No. 24 zirconium corundum, wherein the sanding pressure is 0.40MPa, the sanding distance is 120mm, the sanding angle is 50 degrees, and after sanding, the compressed air is used for blowing off possible residual sand grains or dust.

And 5: plasma spraying of a NiCrAlY coating is carried out on a region to be sprayed, and the specific parameters are as follows: the current is 620A, the voltage is 82V, the argon gas is 64L/min, the hydrogen gas is 16L/min, the powder feeding amount is 40g/min, the spraying distance is 135mm, the carrier gas is 6.0L/min, the spraying angle is 53 degrees, the rotating speed of the rotary table is 350rpm, and the spraying is carried out until the thickness of the coating meets the requirement.

Example 5

And step 3: and sanding the area to be sprayed by using No. 24 zirconium corundum, wherein the sanding pressure is 0.40MPa, the sanding distance is 120mm, the sanding angle is 55 degrees, and after sanding, the compressed air is used for blowing off possible residual sand grains or dust.

And 5: plasma spraying of a NiCrAlY coating is carried out on a region to be sprayed, and the specific parameters are as follows: the current is 630A, the voltage is 83V, the argon gas is 67L/min, the hydrogen gas is 12L/min, the powder feeding amount is 42g/min, the spraying distance is 143mm, the carrier gas is 2.0L/min, the spraying angle is 55 degrees, the rotating speed of the rotary table is 270rpm, and the spraying is carried out until the thickness of the coating meets the requirement.

The microstructure of the coatings provided in examples 1 to 5 was observed, and the results are shown in FIGS. 3 to 7. According to the microstructure diagram, the performance of the casing coating obtained by the method provided by the invention meets the use requirement. The sprayed casing is assembled on an aeroengine for experiment, and the stable running time index is reached. The casing obtained by spraying by the method provided by the invention can meet the requirement of stable operation of an aeroengine.

The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Claims

1. A method for locally plasma-spraying a NiCrAlY coating on the inner wall of an aluminum alloy casing with a boss is characterized by comprising the following steps of: carrying out dust and oil removal treatment on a cartridge receiver, then protecting a non-spraying area, carrying out surface sanding and roughening treatment on an area to be sprayed, putting the cartridge receiver into a clamp and fixing the cartridge receiver on a rotary table, and spraying a NiCrAlY coating on the area to be sprayed;

the sanding and coarsening process comprises the following steps: sanding pressure is 0.2 MPa-0.4 MPa, sanding distance is 100-150 mm, sanding angle is 35-60 degrees, and surface roughness Ra of the area to be sprayed after sanding treatment is more than 3 mu m;

the process for spraying the NiCrAlY coating comprises the following steps: the current is 600-640A, the voltage is 80-84V, the argon gas is 63-67L/min, the hydrogen gas is 12-16L/min, the powder delivery amount is 35-45 g/min, the spraying distance is 135-145 mm, the carrier gas is 2.0-7.0L/min, the spraying angle is 45-55 degrees, and the rotating speed of the rotary table is 270-350 rpm; the powder of the spray coating is NiCrAlY powder, and the granularity is-105 +53 mu m;

in the spraying process, in the process that the spray gun is moved from the original position to the spraying initial position, the spraying is ensured not to reach the area to be sprayed, the inner hole and the outer wall to be sprayed are cooled by air cooling, the temperature of the matrix is not more than 200 ℃, when the temperature of the area to be sprayed is more than 150 ℃, the spraying is stopped, the spraying is continued when the temperature is reduced to be below 100 ℃, and the steps are repeated until the thickness meets the requirement.

2. The method for locally plasma-spraying the NiCrAlY coating on the inner wall of the aluminum alloy casing with the boss as claimed in claim 1, wherein the sanding pressure is 0.3MPa to 0.35MPa, the sanding distance is 120mm to 130mm, and the sanding angle is 45 ° to 50 °.

3. The method for locally plasma-spraying the NiCrAlY coating on the inner wall of the aluminum alloy casing with the boss according to claim 1, wherein the sand material subjected to sanding and coarsening treatment comprises at least one of white corundum, brown corundum and zirconium corundum, and the granularity of the sand material is 24# to 46 #.