Spraying chromium oxide composite ceramic bushing

Abstract

The utility model belongs to mechanical seal technical field discloses a kind of spraying chromium oxide composite ceramic shaft sleeve for mechanical seal, to solve the problem of easy wear, low life of existing technology shaft sleeve component, the composite ceramic shaft sleeve includes shaft sleeve body, the one end of shaft sleeve body is equipped with boss for installing dynamic ring, the other end of shaft sleeve body is equipped with recess for installing snap spring, the middle part of shaft sleeve body is equipped with installation slot for installing static ring and spring seat, installation slot and recess are equipped with reserved slot, reserved slot is equipped with chromium oxide spraying layer.The utility model is sprayed by being arranged at the skeleton oil seal of shaft sleeve, coating surface roughness can reach Ra0.2, surface is more smooth, hardness can reach HV1200-1300, hardness is promoted about 5 times, wear resistance is better, the life of shaft sleeve and skeleton oil seal is all greatly reduced cost and improved.The utility model can greatly improve product performance ratio by local spraying.

Description

Technical Field

[0001] This utility model relates to the field of mechanical seal technology, specifically to a sprayed chromium oxide composite ceramic bushing for mechanical seals. Background Technology

[0002] The bushing is one of the key components of a mechanical seal. Currently, bushings are usually made of stainless steel with a surface roughness of Ra1.6 and a surface hardness of HV200-300. This has the following problems: when the mechanical seal uses a skeleton oil seal at the water sealing end, a friction pair is formed between the bushing and the skeleton oil seal, which leads to mutual wear between the two. The bushing needs to be replaced frequently, which also seriously affects the life of the entire mechanical seal. The above technical problems cannot be solved at present. Utility Model Content

[0003] This invention aims to solve the problems of easy wear and short lifespan in existing bushing components by proposing a sprayed chromium oxide composite ceramic bushing.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A chromium oxide composite ceramic bushing includes a bushing body, one end of which is provided with a boss for mounting a rotating ring, the other end of which is provided with a groove for mounting a retaining ring, and the middle part of the bushing body is provided with a mounting groove for mounting a stationary ring and a spring seat. A reserved groove is provided between the mounting groove and the recess, and a composite chromium oxide ceramic spray coating is provided in the reserved groove.

[0006] Furthermore, the bottom of the reserved groove is threaded.

[0007] Furthermore, the inner edge of the boss is provided with a first chamfer for mounting a tip; the inner edge of the bushing body at the other end away from the boss is provided with a second chamfer for mounting a tip.

[0008] Furthermore, the depth of the reserved groove is 0.2 mm-0.25 mm.

[0009] Furthermore, both sides of the reserved groove are chamfered.

[0010] Furthermore, the composite chromium oxide ceramic coating consists of a metal transition layer, a metal-ceramic hybrid layer, and a chromium oxide layer from the inside out, with each layer having a thickness of 50μm-100μm.

[0011] Furthermore, the chromium oxide layer is composed of 5%-10% nano-alumina particles added to a chromium oxide matrix.

[0012] Furthermore, 5% molybdenum disulfide is added to the chromium oxide matrix.

[0013] Compared with the prior art, this utility model has the following advantages:

[0014] This invention features a pre-reserved groove at the mounting point of the shaft sleeve and a composite spray coating applied to it. After applying the composite chromium oxide ceramic spray coating, the surface roughness of the pre-reserved groove reaches Ra0.2 (through three processes: rough grinding, fine grinding, and polishing), resulting in a smoother surface. The hardness of the pre-reserved groove reaches HV1200-1300, an increase of approximately 5 times, leading to better wear resistance. This significantly extends the lifespan of both the shaft sleeve and the oil seal, reducing operating costs and the frequency of mechanical seal replacement. Through localized spraying, this invention greatly improves the product's cost-effectiveness.

[0015] This invention improves the adhesion of the sprayed coating by setting process threads at the bottom of the pre-reserved spraying groove, making the coating less prone to peeling off. The first and second chamfers facilitate automatic center alignment during subsequent grinding. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the bushing body of this utility model.

[0017] Figure 2 for Figure 1 A magnified view of a portion of the image.

[0018] Figure 3 This is a schematic diagram of the structure of the bushing wear debris of this utility model.

[0019] Figure 4 This is a structural schematic diagram of the finished bushing of this utility model.

[0020] Figure 5 This is a schematic diagram of the structure of the composite chromium oxide ceramic spray coating of this utility model.

[0021] The meanings of the reference numerals in the attached drawings are as follows: 1. Bushing body; 2. Mounting groove; 3. Reserved groove; 4. Groove; 5. Second chamfer; 6. First chamfer; 7. Boss; 8. Thread; 9. Composite chromium oxide ceramic spray coating; 10. Top; 11. Metal transition layer; 12. Metal-ceramic hybrid layer; 13. Chromium oxide layer. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1-5As shown, a chromium oxide composite ceramic bushing includes a bushing body 1 made of stainless steel. One end of the bushing body 1 has a boss 7 for installing the rotating ring of a mechanical seal, and the other end has a groove 4 for installing a retaining spring in the mechanical seal. The middle of the bushing body 1 has an installation groove 2 for installing the stationary ring and spring seat of the mechanical seal. A reserved groove 3 is provided between the installation groove 2 and the groove 4, with a groove depth of 0.2mm-0.25mm. Both sides of the reserved groove 3 have chamfers. The bottom of the reserved groove 3 has threads, and a composite chromium oxide ceramic coating layer 9 is applied inside the reserved groove 3. The composite chromium oxide ceramic coating layer 9 consists of a metal transition layer 11, a metal-ceramic hybrid layer 12, and a chromium oxide layer 13, from the inside out, with each layer having a thickness of 50μm-100μm. The chromium oxide layer 13 consists of 5%-10% nano-alumina particles (0.1-1μm in diameter) added to the chromium oxide matrix, forming a "nano-reinforcing phase". This increases hardness by 20-30% and improves wear resistance by 40%. 5% molybdenum disulfide is also added to the chromium oxide matrix to enhance self-lubrication.

[0024] The inner edge of the boss 7 is provided with a first chamfer 6 for mounting the center 10; the inner edge of the bushing body 1 at the other end away from the boss 7 is provided with a second chamfer 5 for mounting the center 10. By setting the first chamfer 6 and the second chamfer 5, the center 10 can be easily aligned by itself during subsequent grinding.

[0025] The specific spraying process of this utility model is as follows:

[0026] Step 1, Surface cleaning and roughening: Alumina sand is used to remove oil, oxide layer and impurities from the surface of the bushing body 1, forming a micro-roughness of Ra≥6.3μm, which enhances the mechanical bonding force between the coating and the substrate.

[0027] Step 2, Degreasing treatment: Thoroughly remove residual grease from the surface through solvent cleaning and high-temperature baking to avoid affecting coating adhesion.

[0028] Step 3, Preheating: Preheat the workpiece to 200-300℃ to eliminate internal stress and reduce thermal shock during spraying, preventing substrate deformation or coating cracking.

[0029] Step 4, Low-temperature spraying: By adjusting the ratio of plasma gas (Ar+H2), the spraying temperature is controlled at 600-800℃ to avoid softening of the steel substrate during annealing. At the same time, an axial powder feeding system is used to spray the powder onto the surface of the pre-reserved groove 3 and process thread 8 on the bushing body 1. The metal transition layer 11, metal-ceramic hybrid layer 12, and chromium oxide layer 13 are sprayed in sequence.

[0030] In this embodiment, the metal transition layer 11 is made of NiCr alloy powder (Ni:Cr=80:20 or 70:30) with a particle size of 15-45μm, suitable for plasma spraying. The metal in the metal-ceramic hybrid layer is also NiCr alloy powder.

[0031] Step 5: After spraying, laser remelting is used: a laser beam (wavelength 1064nm) is used to quickly scan the coating surface, so that the surface layer of 10-20μm melts and then solidifies quickly, achieving a smoothness of less than Ra0.4μm, while reducing dust pollution.

[0032] After being coated with chromium oxide composite ceramic, the semi-finished ceramic bushing is transformed into a finished bushing through three processes: rough grinding, fine grinding, and polishing. The surface roughness of the coating layer of the finished bushing can reach Ra0.2, and the hardness can reach HV1200-1300.

Claims

1. A chromium oxide-coated composite ceramic bushing, comprising a bushing body (1), characterized in that: One end of the bushing body (1) is provided with a boss (7) for installing the rotating ring, and the other end of the bushing body (1) is provided with a groove (4) for installing the snap ring. The middle part of the bushing body (1) is provided with an installation groove (2) for installing the stationary ring and the spring seat. A reserved groove (3) is provided between the installation groove (2) and the groove (4). The bottom of the reserved groove (3) is provided with a thread (8), and the reserved groove (3) is provided with a composite chromium oxide ceramic spray coating (9).

2. The chromium oxide composite ceramic bushing according to claim 1, characterized in that: The composite chromium oxide ceramic spray coating (9) consists of a metal transition layer (11), a metal-ceramic hybrid layer (12), and a chromium oxide layer (13) from the inside out, with each layer having a thickness of 50μm-100μm.

3. The chromium oxide composite ceramic bushing according to claim 1, characterized in that: The inner edge of the boss (7) is provided with a first chamfer (6) for mounting the tip (10); the inner edge of the bushing body (1) away from the boss (7) is provided with a second chamfer (5) for mounting the tip (10).

4. The chromium oxide composite ceramic bushing according to claim 2, characterized in that: The depth of the reserved groove (3) is 0.2mm-0.25mm.

5. A chromium oxide composite ceramic bushing according to claim 4, characterized in that: Both sides of the reserved groove (3) are chamfered.

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