Supersonic flame spraying method for thin-wall plane part

Abstract

The invention relates to the technical field of part spraying, in particular to a thin-wall plane part supersonic flame spraying method which comprises the following steps: S1, fixing a thin-wall part: mounting a vacuum adsorption device on a working platform, and adsorbing the back surface of the thin-wall part to be sprayed by using the vacuum adsorption device; s2, hypersonic flame spraying is conducted, specifically, spraying equipment drives a spray gun to move along a set path to conduct spraying, and in the spraying process, a gun head of the spray gun swings synchronously till spraying is completed; and S3, laser post-treatment modification is conducted, specifically, laser equipment is used for conducting laser irradiation on the coating sprayed on the thin-wall part according to a set track so that the surface of the coating can be melted, and therefore pores in the surface of the coating can be sealed. The thin-wall plane part can be fixed without shielding, the integrity and the service life of the coating are guaranteed, meanwhile, thermal deformation of the thin-wall plane part can be reduced, and the hardness of the coating is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of part spraying, in particular to a thin-walled planar part high-velocity oxygen fuel spraying method. BACKGROUND

[0002] In the field of high-velocity oxygen fuel spraying (HVOF) of thin-walled planar parts, the traditional fixing method mainly relies on mechanical clamping or screw fastening to fix the thin-walled planar parts. For example, the thin-walled planar parts are fixed on the spraying station through clamping bodies or reserved screw holes.

[0003] Although the above-mentioned method can realize stable clamping of the thin-walled planar parts, it will block the spraying surface, resulting in that the coating coverage rate cannot reach 100%. After spraying, the fixed parts need to be removed through mechanical processing, but this process is easy to cause stress concentration or even cracking of the coating edge, affecting the integrity and service life of the coating. During the spraying process, the thin-walled planar parts have low rigidity, and the spraying path is usually one-way or fixed-angle reciprocating motion, which cannot effectively disperse thermal stress, resulting in difficult control of the deformation of the thin-walled planar parts. Under the impact of high temperature, thermal deformation is easy to occur, further aggravating the problem of uneven coating or base warping. Meanwhile, during the high-velocity oxygen fuel spraying process, the tungsten carbide powder will undergo decarburization reaction at high temperature, resulting in a decrease in the hardness of the coating.

[0004] Therefore, a thin-walled planar part high-velocity oxygen fuel spraying method is needed to solve the above-mentioned problems. SUMMARY

[0005] The present application aims to provide a thin-walled planar part high-velocity oxygen fuel spraying method, which can fix the thin-walled planar parts without blocking, ensure the integrity and service life of the coating, and reduce the thermal deformation of the thin-walled planar parts and improve the hardness of the coating.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] The thin-walled planar part high-velocity oxygen fuel spraying method comprises the following steps:

[0008] S1, fixing the thin-walled part: installing a vacuum adsorption device on a workbench, and adsorbing the back surface of the thin-walled part to be sprayed by using the vacuum adsorption device;

[0009] S2, high-velocity oxygen fuel spraying: the spraying equipment drives the spray gun to move along the set path for spraying, and the gun head of the spray gun swings synchronously during the spraying process until the spraying is completed;

[0010] S3, laser post-processing modification: using a laser equipment to irradiate the coating on the thin-walled part according to the set track, so that the coating surface is melted to close the pores on the coating surface.

[0011] In some embodiments, before the step S1, the surface of the thin-walled part is sandblasted to remove impurities and oxides.

[0012] In some embodiments, after sandblasting, the surface of the thin-walled part is cleaned with acetone to remove residual sand and stains, or the surface of the thin-walled part is blown with compressed air.

[0013] In some embodiments, in the step S1, a sealing ring is arranged on the surface of the suction cup of the vacuum suction device.

[0014] In some embodiments, in the step S1, the vacuum suction device has an extension rod, and the extension rod is clamped by a clamping tool on the working platform to fix the vacuum suction device.

[0015] In some embodiments, in the step S2, the set path is parallel to the horizontal center line of the thin-walled part.

[0016] In some embodiments, in the step S2, the swing angle of the gun head of the spray gun relative to the surface of the thin-walled part ranges from 60° to 90°.

[0017] In some embodiments, after the step S3, the thickness, porosity, bonding strength and microhardness of the coating are tested.

[0018] In some embodiments, a thickness gauge is used to measure the thickness of the coating.

[0019] In some embodiments, the porosity of the coating is evaluated by observing the cross section of the coating through a metallographic microscope.

[0020] The beneficial effects of the present application are as follows:

[0021] The method comprises the following steps: a vacuum adsorption device is used to fix and adsorb the thin-wall part, a spraying device drives a spray gun to move along a set path to spray, the spray gun head swings synchronously during the spraying process until the spraying is completed, and a laser device is used to irradiate the coating on the thin-wall part according to a set track to make the coating surface melt, so as to close the pores on the coating surface. The back surface of the thin-wall part to be sprayed is adsorbed by the vacuum adsorption device, so that the thin-wall part to be sprayed is not blocked, the integrity of the coating is ensured, and the service life of the coating is ensured without subsequent mechanical processing to remove the fixed part. During the spraying process, the spray gun head swings synchronously during movement, the thin-wall part is sprayed by the above method, the coating is uniformly distributed, and local overheating caused by deformation can be avoided. Through laser modification technology, the coating surface is scanned and modified by laser, the coating particles are directionally slightly melted, the pores on the coating surface are closed, the pores between the coatings are reduced, the surface quality and corrosion resistance of the coating are improved, and a high-quality, high-hardness wear-resistant coating is prepared. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of the contents of the embodiments of the present application and the drawings.

[0023] Figure 1 is a flow chart of the method for supersonic flame spraying of the thin-wall planar part. DETAILED DESCRIPTION

[0024] Before any embodiments of the present application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above-described drawings.

[0025] In the present application, the terms "comprise", "contain", "have" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0026] In this application, the terms "connect", "combine", "couple", "mount" can be direct connection, combination, coupling or mounting, or indirect connection, combination, coupling or mounting. Among them, for example, direct connection refers to the connection of two parts or components without the need for an intermediate part, and indirect connection refers to the connection of two parts or components with at least one intermediate part. In addition, "connection" and "coupling" are not limited to physical or mechanical connection or coupling, and can include electrical connection or coupling.

[0027] In this application, those of ordinary skill in the art will understand that the functions performed by the components can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by the parts can also be performed by one part, one component, or multiple parts in combination.

[0028] In this application, the terms "up", "down", "left", "right", "front", "back" and the like are described in the orientation and positional relationship shown in the drawings, and should not be understood as limiting the embodiments of the application. In addition, it should also be understood in the context that when referring to one element connected to another element "on" or "below", it can be directly connected to another element "on" or "below", or indirectly connected to another element "on" or "below" through an intermediate element. It should also be understood that the terms "up", "down", "left", "right", "front", "back" and the like not only represent the positive direction, but also can be understood as the side direction. For example, the lower side can include the lower side, the lower left side, the lower right side, the lower front side and the lower back side, etc.

[0029] In the process of spraying on the surface of the thin-walled part, in order to be able to fix the thin-walled planar part without shielding, ensure the integrity and service life of the coating, and at the same time reduce the thermal deformation of the thin-walled planar part and improve the hardness of the coating, as shown in Figure 1 As shown in the drawings, the present application provides a thin-walled planar part supersonic flame spraying method. The thin-walled planar part supersonic flame spraying method comprises the following steps:

[0030] S1, fixing the thin-walled part: installing a vacuum adsorption device on the working platform, and adsorbing the back of the thin-walled part to be sprayed by the vacuum adsorption device;

[0031] S2, supersonic flame spraying: the spraying equipment drives the spray gun to move along the set path for spraying, and the gun head of the spray gun swings synchronously during the spraying process until the spraying is completed;

[0032] S3, laser post-processing modification: using a laser device to irradiate the coating on the thin-walled part according to the set track, so that the coating surface is melted, thereby sealing the pores on the coating surface.

[0033] The vacuum suction device is used to suck the back surface of the to-be-sprayed surface of the thin-walled part, so that the to-be-sprayed surface of the thin-walled part is not blocked and fixed, the integrity of the coating is ensured, and the fixed part does not need to be removed by subsequent machining, so that the service life of the coating is ensured. During the spraying process, the gun head of the spray gun swings synchronously during movement, the thin-walled part is sprayed by the above-mentioned mode, the uniform distribution of the coating is ensured, and the deformation caused by local overheating is avoided. Through the laser modification technology, the coating surface is scanned and modified by laser, the coating particles are directionally micro-fused, the pores on the coating surface are closed, the inter-coating pores are reduced, the surface quality and corrosion resistance of the coating are improved, and a high-quality, high-hardness wear-resistant coating is prepared.

[0034] In some embodiments, before step S1, the surface of the thin-walled part is also pretreated by sand blasting to ensure that impurities and oxides on the surface of the thin-walled part are removed. By performing sand blasting pretreatment, the surface roughness of the thin-walled part is increased while the surface of the thin-walled part is cleaned, and the bonding ability of the coating is improved.

[0035] In some embodiments, after sand blasting, the surface of the thin-walled part is cleaned with acetone to remove residual sand particles and stains, or the surface of the thin-walled part is blown with compressed air. By the above-mentioned mode, the surface of the thin-walled part is ensured to be clean and free of impurities, and the subsequent spraying is prepared.

[0036] In some embodiments, in step S1, a sealing ring is arranged on the surface of the suction cup of the vacuum suction device. Specifically, the suction cup is made of stainless steel material, the surface is smooth, and has good high-temperature resistance and corrosion resistance. Four grooves are uniformly arranged around the edge of the suction cup, the sealing ring is embedded in the grooves, and one end of the sealing ring protrudes relative to the grooves. After the suction cup of the vacuum suction device is adsorbed to the thin-walled part to be sprayed, the sealing ring is deformed by extrusion, thereby effectively blocking the gap between the suction cup and the thin-walled part, to improve the sealing effect of the vacuum adsorption. When the thin-walled part is adsorbed, the vacuum pump is connected to the adapter of the suction cup in the tool through a hose, the vacuum pump is adjusted to a suitable vacuum degree, to ensure the strength and stability of the adsorption. The thin-walled part to be sprayed is placed on the surface of the suction cup, to ensure that the thin-walled part is in good contact with the surface of the suction cup. The vacuum pump is started, and the thin-walled part is adsorbed and stably fixed by negative pressure.

[0037] In some embodiments, in step S1, the vacuum suction device has an extension rod, and the extension rod is clamped by a clamping tool on the working platform to fix the vacuum suction device. By the above-mentioned mode, the vacuum suction device can be effectively fixed, so that the position of the thin-walled part does not change, the stability and reliability of the thin-walled part during the spraying operation are ensured, and uneven spraying caused by vibration or movement is avoided.

[0038] In some embodiments, in step S2, the path is set parallel to the horizontal center line of the thin-walled part. By setting the spraying path, effective spraying of the thin-walled part can be ensured, and the situation of missing or not spraying in place can be avoided.

[0039] In some embodiments, in step S2, the swing angle of the gun head of the spray gun relative to the surface of the thin-walled part is 60°-90°. A wider swing angle helps to uniformly cover the coating and reduces local overheating and thermal deformation of the part during spraying.

[0040] In some embodiments, a suitable spraying powder material is selected, and the spraying parameters are matched to start spraying the surface of the part. The spray gun is kept at a suitable vertical distance from the surface of the part, and the specific distance can be adjusted according to the material properties and spraying effect. During spraying, stable airflow and powder supply need to be maintained to ensure the continuity and consistency of the coating. The state of the part is observed, and if necessary, the spraying speed or powder flow is adjusted to obtain the best spraying effect.

[0041] In some embodiments, after spraying is completed, the laser scanning speed, laser power, spot size, and overlap rate of the laser equipment are adjusted to modify the coating. After spraying is completed, the coating is post-processed by laser. The high heat of the laser can cause the surface of the coating to be slightly melted, thereby sealing the pores on the surface of the coating and improving the surface quality and corrosion resistance of the coating. In addition, laser post-processing can also improve the organizational structure of the coating to some extent, thereby improving the hardness and wear resistance of the coating.

[0042] In some embodiments, after step S3, the thickness, porosity, bonding strength, and microhardness of the coating need to be tested. Through the above tests, the spraying effect can be inspected.

[0043] In some embodiments, a thickness gauge is used to measure the thickness of the coating. Since the coating is too thin, it may not have sufficient wear resistance and corrosion resistance; if it is too thick, it may increase the internal stress of the coating, resulting in a decrease in bonding strength. Therefore, the thickness of the coating is measured using a thickness gauge to ensure that the thickness of the coating is within a suitable range and meets the protection requirements of the thin-walled part.

[0044] Since a high porosity will affect the density and corrosion resistance of the coating, in some embodiments, the cross-section of the coating is observed by a metallographic microscope to evaluate the porosity, so as to ensure that the porosity is less than 1%.

[0045] Since insufficient bonding strength may cause the coating to peel off and affect the service life, the bonding strength of the coating to the substrate is evaluated by a tensile test or other bonding strength test methods to ensure that the bonding strength is above 70 MPa.

[0046] In some embodiments, the microhardness test is performed by preparing a sample by metallographic method, and measuring the microhardness of the cross section of the coating by a microhardness tester, to ensure that the microhardness is increased by more than 15% compared with the coating without laser modification.

[0047] Through the above steps, not only the thin-walled part is sprayed by supersonic flame under the condition of no shielding, but also the deformation of the thin-walled part in the spraying process is significantly reduced by optimizing the spraying path and the fixing method of the tool, so as to meet the application requirements of high-strength and high-precision parts in the field of aviation and the like.

[0048] A thin-walled part is sprayed by the above method: the surface of the thin-walled part is sandblasted before spraying, 46-mesh white corundum sand is used, sandblasting is carried out at a pressure of 0.3 MPa, and the residual sand particles on the surface of the thin-walled part are removed by acetone cleaning or compressed gas. Commercially available tungsten carbide cobalt chromium powder (cobalt content 10%; chromium content 4%) is used as raw material, the particle size of the powder is 15 μm-45 μm, a wear-resistant coating is prepared by supersonic flame spraying, and the spraying distance is 255 mm. The prepared coating is modified by laser power of 1.2 kW, scanning speed of 20 mm / s, and overlap rate of 50%. In this process, the porosity of the coating is less than 1%, the sprayed coating thickness is not less than 0.3 mm, and the coating bonding strength is greater than or equal to 70 MPa by selecting the process parameters in the spraying process. The thickness of the tungsten carbide cobalt chromium coating prepared in this process is 0.40 mm, the porosity is 0.26%, the coating bonding strength is 81 MPa, and the coating coverage rate of the thin-walled part can reach 100%.

[0049] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the implementation modes are not required or can not be exhausted. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A method of supersonic flame spraying thin-walled planar parts, characterized in that The method comprises the following steps: S1, fixing the thin-walled part: installing a vacuum adsorption device on the workbench, and adsorbing the back of the thin-walled part to be sprayed by using the vacuum adsorption device; S2, supersonic flame spraying: the spraying equipment drives the spray gun to move along the set path for spraying, and the gun head of the spray gun swings synchronously during the spraying process until the spraying is completed; S3, laser post-processing modification: using a laser device to irradiate the coating on the thin-walled part according to the set track, so that the coating surface is melted, thereby sealing the pores on the coating surface.

2. The thin-walled planar part method of claim 1 wherein, Before the step S1, the method further comprises a pretreatment: sandblasting the surface of the thin-walled part to ensure that impurities and oxides on the surface of the thin-walled part are removed.

3. The thin-walled planar part method of claim 2, wherein, After sandblasting, the surface of the thin-walled part is cleaned with acetone to remove residual sand particles and stains, or compressed air is used to blow the surface of the thin-walled part.

4. The thin-walled planar part method of claim 1 wherein, In the step S1, a sealing ring is arranged on the surface of the suction cup of the vacuum adsorption device.

5. The thin-walled planar part method of claim 1 wherein, In the step S1, the vacuum adsorption device has an extension rod, and the extension rod is clamped by a clamping tool on the workbench to fix the vacuum adsorption device.

6. The thin-walled planar part method of claim 1 wherein, In the step S2, the set path is parallel to the horizontal center line of the thin-walled part.

7. The thin-walled planar part method of claim 1 wherein, In the step S2, the swing angle of the gun head of the spray gun relative to the surface of the thin-walled part ranges from 60° to 90°.

8. The thin-walled planar part method of claim 1 wherein, After the step S3, the thickness, porosity, bonding strength and microhardness of the coating need to be tested.

9. The thin-walled planar part method of claim 8, wherein, A thickness gauge is used to measure the thickness of the coating.

10. The thin-walled planar part method of claim 8, wherein, The cross-section of the coating is observed by a metallographic microscope to evaluate the porosity.

Images