CN111647837B

CN111647837B - Shielding method for preparing hot spraying thick coating

Info

Publication number: CN111647837B
Application number: CN202010698248.5A
Authority: CN
Inventors: 于月光; 侯伟骜; 刘建明; 沈婕; 卢晓亮; 冀晓鹃; 万伟伟; 章德铭
Original assignee: Bgrimm Advanced Materials Science & Technology Co ltd; BGRIMM Technology Group Co Ltd
Current assignee: Bgrimm Advanced Materials Science & Technology Co ltd; BGRIMM Technology Group Co Ltd
Priority date: 2020-07-20
Filing date: 2020-07-20
Publication date: 2022-08-09
Anticipated expiration: 2040-07-20
Also published as: CN111647837A

Abstract

A shielding method for preparing a hot spraying thick coating belongs to the technical field of hot spraying. The metal splicing tool and the multi-layer protective adhesive tape are combined for protection to shield the non-spraying part of the part, and the over-spraying part of the coating in the shielding area is removed in a mode of peeling off the protective adhesive tape gradually in the spraying process, so that the integrity and regular transition of the edge of the thick coating and the protection of the non-spraying part are realized, the problems that the adhesive tape is adhered to the coating, the edge of the coating is easy to break and block off and the like in the preparation process of the thick coating are effectively solved, the product quality and the yield are obviously improved, and the metal splicing tool is suitable for various thermal spraying processes such as flame spraying, atmospheric plasma spraying, electric arc spraying and the like.

Description

Shielding method for preparing hot spraying thick coating

Technical Field

The invention belongs to the technical field of thermal spraying, and relates to a shielding method for preparing a thermal spraying thick coating.

Background

The non-spraying area needs to be effectively protected in the preparation process of the thermal spraying coating, and the conventional protection shielding method mainly comprises adhesive tape protection, compound protection and tool protection. Due to the continuity of the coating across the surface of the mask in both the spray and non-spray areas, the mask removal process is prone to damage to the coating edges. In addition, the coating and the surface which is not sprayed can generate a step difference of approximately 90 degrees, stress concentration is generated, the step difference is a main part of coating edge breakage, cracking, falling and failure, and the step difference effect is particularly obvious for hot spraying of thick coatings. Because the bonding strength of the thick coating is low and the shape of the part is limited, the manual or automatic grinding and trimming of the edge of the hot spraying thick coating has low efficiency and is easy to break the edge, the trimming angle is difficult to control, the surface of a nearby matrix is easy to damage, and the requirements of the coating performance and the production cycle are difficult to meet.

People urgently need a shielding method for preparing a hot spraying thick coating, and the problems that a protective adhesive tape is adhered to the coating, the edge of the coating is easy to collapse and block and the like in the preparation process of the thick coating are solved.

Disclosure of Invention

The invention aims to solve the technical problems and provides a shielding method for preparing a hot spraying thick coating, which adopts a metal splicing tool and a plurality of layers of protective tapes for combined protection to shield the part which is not sprayed on the part, and removes the overspray part of the coating in the shielding area by gradually peeling off the protective tapes in the spraying process, thereby realizing the complete and regular transition of the edge of the thick coating and the protection of the part which is not sprayed, effectively solving the problems that the protective tapes are adhered to the coating, the edge of the coating is easy to break and block, and the like in the preparation process of the thick coating, being suitable for various hot spraying processes such as flame spraying, atmospheric plasma spraying, electric arc spraying, and the like, and being suitable for industrial production operation. The purpose of the invention is realized by the following technical scheme.

A masking method for preparing a thick thermal sprayed coating, comprising the steps of:

(1) cleaning and degreasing parts and performing sand blowing pretreatment on the sprayed surfaces, and cleaning and degreasing the surfaces of workpieces and roughening the surfaces of coating parts by adopting a conventional treatment process.

(2) Shielding and protecting the uncoated area by adopting a thermal spraying protective adhesive tape: the surface adjacent to the spraying surface is progressively protected by adopting a plurality of layers of adhesive tapes, and the non-adjacent surface is integrally protected by adopting a single layer of adhesive tape;

(3) carrying out secondary shielding protection on the uncoated area by adopting a splicing type metal tool;

(4) finishing the preparation of the thick coating by adopting an intermittent spraying mode, and removing the protective adhesive tapes on the adjacent surfaces of the spraying surfaces layer by layer in the spraying process;

(5) and (4) after the thickness of the coating reaches the design requirement, removing the metal tool and the residual protective adhesive tape to finish the preparation of the coating.

In some embodiments, the surface adjacent to the spraying surface in the step (2) is progressively protected by using a multilayer adhesive tape, specifically: and (3) adopting 3-6 layers of protective adhesive tapes, starting from a position 5-10 mm away from the edge of the spraying surface, pasting layer by layer from far to near relative to the edge of the spraying surface, extending a certain length (for example, 1mm) from the edge of each layer to the spraying area compared with the edge of the previous layer until the edge of each layer is flush with the edge of the spraying area, and trimming the edge of each layer of protective adhesive tape.

In some specific embodiments, the spliced metal tool in the step (3) is made of a copper plate, has a thickness of 0.5-3 mm, a surface roughness of less than Ra1.6 μm, and has an arc-shaped edge chamfered, the tool is connected by a thread in a combined mode, and the tool is fixed by a clamping mode (such as a I-shaped clamp); the metal tool and the protective adhesive tape are completely compressed, and the edge of the tool is flush with the edge of the spraying area.

In some embodiments, the step (4) of removing the protective tape on the spraying transition area layer by layer specifically includes: in the spraying process, disassembling a tool once when the thickness of the coating is increased by 0.1-0.3 mm, removing the foremost layer of adhesive tape on the adjacent surface of the spraying surface, and continuing spraying after a rubber tool is used for simply cleaning the edge of the coating; and disassembling the tool once every time the coating is thickened by 0.5-0.8 mm, removing the foremost layer of adhesive tape on the adjacent surface of the spraying surface, simply cleaning local residues on the edge of the coating by using a rubber tool, assembling the tool and continuously spraying until the thickness of the coating reaches the process requirement. Further, the time interval between each removal of the protective tape and the re-spraying was < 5 min.

In the traditional process of preparing the hot spraying thick coating, the protective adhesive tape is inevitably adhered to the coating, and edge breakage and local cracking of the coating are easily caused no matter the protective adhesive tape is removed by adopting a manual file trimming mode or a mechanical processing mode on the edge of the coating after the spraying is finished. The metal shielding tool is easy to deform due to the fact that the continuous spraying time of the thick coating is long, so that gaps are generated between the tool and the shielding surface of the part, and the shielding effect is greatly reduced. The metal splicing tool and the multi-layer protective adhesive tape are combined for protection, the protective adhesive tape is prevented from being adhered to the coating by removing the protective adhesive tape layer by layer in the spraying process, and meanwhile, the splicing type shielding tool is made of a smooth copper plate, so that the metal splicing tool is good in heat conductivity, strong in deformation resistance, convenient to disassemble quickly and capable of shortening the spraying interval time. The method solves the problems of adhesion between the protective tape and the coating, easy edge breakage and block dropping of the coating edge and the like in the preparation process of the thick coating, can ensure smooth transition of the coating edge, improves the edge coating quality and yield of the hot spraying thick coating, and is suitable for industrial production operation.

Drawings

FIG. 1 is a schematic view of a spray coated substrate.

FIG. 2 is a schematic view showing how the protective tape adheres to different areas when the first coating layer is sprayed.

FIG. 3 is a schematic view of the shielding and clamping of the I-shaped metal tool on the I-shaped area of the sprayed substrate.

FIG. 4 is a schematic view showing how the protective tape adheres to different areas when a second coating layer is sprayed.

FIG. 5 is a schematic view of the final coating corner morphology with a gradual transition in thickness.

Reference numerals: i-a non-spraying area, II-a spraying transition area and III-a spraying area; 1-spraying a base material, 2-an I-shaped metal tool, 3-a fixing hole, 4-7-a protective adhesive tape, 8-a first coating, 9-a second coating and 10-a final coating.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Preparation of thick sealing coating of compressor balance disc

Step 1, scrubbing and degreasing the surface of a workpiece by alcohol, shielding a non-coating part by using a sand-blasting protective tape, roughening the surface of the coating part by using 22-mesh white corundum sand and 0.8MPa press-in type sand blasting, removing the sand-blasting protective tape after roughening, and blowing and cleaning the part by using clean compressed air. As shown in fig. 1, the spray substrate 1 can be divided into a non-spray area I, a spray transition area II, and a spray area III.

And 2, as shown in fig. 2, starting to adopt a protective adhesive tape to protect the surface adjacent to the spraying surface from a position 4mm away from the edge of the spraying surface, sticking the protective adhesive tapes 4-7 layer by layer from far to near relative to the edge of the spraying surface, extending the edge of each layer to the spraying area by 1mm compared with the edge of the previous layer until the edge of each layer is flush with the edge of the spraying area, and trimming the edge of the protective adhesive tape at the outermost side by using a sharp cutter. And the other non-adjacent surfaces are integrally protected by adopting a single-layer protective adhesive tape, and the metal tool 2 and the protective adhesive tapes 4-7 are completely compressed.

And 3, performing secondary shielding protection on the uncoated area by adopting a spliced metal tool as shown in fig. 3. The tool is made of 1mm pure copper plates, the surface of the tool is polished, and the edge of the tool is chamfered by an arc. The tool is connected with the part through the fixing hole 3 by a screw and is fixed with the part by an I-shaped clamp. The metal tool and the protective adhesive tape are completely compressed, and the distance is adjusted to enable the edge of the tool to be flush with the edge of the spraying area.

And 4, preparing the thick coating by adopting an intermittent spraying mode. As shown in fig. 4, in the spraying process, when the thickness of the first coating 8 reaches 0.3mm, the metal tool is dismantled, the foremost layer of protective adhesive tape 7 on the adjacent surface of the spraying surface is removed, the edge of the coating is cleaned by using a rubber hammer, and the tool is installed for continuous spraying; disassembling the tool when the thickness of the second coating 9 reaches 0.5mm, removing the foremost layer of protective adhesive tape 6, quickly cleaning local residues on the edge of the coating by using a rubber hammer, assembling the tool and continuously spraying; and (4) disassembling the tool once when the thickness of the coating is increased by 0.5mm, removing the foremost layer of protective adhesive tape, cleaning the edge of the coating by using a rubber hammer, assembling the tool and continuously spraying until the thickness of the coating reaches the design requirement.

And 5, as shown in fig. 5, removing the metal tool and the residual protective adhesive tape to complete the preparation of the coating, so as to obtain the final coating 10.

Claims

1. A masking method for preparing a thick thermal sprayed coating, comprising the steps of:

(1) cleaning and degreasing parts and performing sand blasting pretreatment on the sprayed surfaces;

(2) shielding and protecting the uncoated area by adopting a thermal spraying protective adhesive tape: the surface adjacent to the spraying surface is progressively protected by adopting a plurality of layers of adhesive tapes, and the non-adjacent surface is integrally protected by adopting a single layer of adhesive tape; the surface adjacent to the spraying surface is progressively protected by adopting a plurality of layers of adhesive tapes, and the method specifically comprises the following steps: adopting 3-6 layers of protective adhesive tapes, starting from a position 5-10 mm away from the edge of the spraying surface, pasting layer by layer from far to near relative to the edge of the spraying surface, extending a certain length of the edge of each layer compared with the edge of the previous layer to the spraying area until the edge of each layer is flush with the edge of the spraying area, and trimming the edge of each layer of protective adhesive tape;

(3) carrying out secondary shielding protection on the uncoated area by adopting a splicing type metal tool; the spliced metal tool is made of copper plates, the thickness of the spliced metal tool is 0.5-3 mm, the surface roughness is less than Ra1.6 mu m, the edges of the spliced metal tool are in arc chamfering, the tool is in threaded connection in a tool combination mode, and the tool is in clamping and fixing in a tool installation mode; the metal tool and the protective adhesive tape are completely compressed, and the edge of the tool is flush with the edge of the spraying area;

(4) the preparation of the thick coating is finished by adopting an intermittent spraying mode, and the protective adhesive tapes on the adjacent surfaces of the spraying surfaces are removed layer by layer in the spraying process, which specifically comprises the following steps: in the spraying process, disassembling a tool once when the thickness of the coating is increased by 0.1-0.3 mm, removing the foremost layer of adhesive tape on the adjacent surface of the spraying surface, simply cleaning the edge of the coating by using a rubber tool, and continuously spraying after the tool is assembled; then disassembling the tool once when the thickness of the coating is increased by 0.5-0.8 mm, removing the foremost layer of adhesive tape on the adjacent surface of the spraying surface, simply cleaning local residues on the edge of the coating by using a rubber tool, assembling the tool and continuously spraying until the thickness of the coating reaches the process requirement;

2. Masking method according to claim 1, characterized in that the time interval between each removal of protective tape and the re-spraying is < 5 min.