Hard alloy mechanical sealing ring and preparation method thereof

Abstract

The invention relates to the technical field of mechanical sealing rings, and provides a hard alloy mechanical sealing ring and a preparation method thereof.According to the hard alloy mechanical sealing ring, an upper-layer ring sintered body and a lower-layer ring which are split are adopted to form a composite ring, and on the premise that it is guaranteed that the composite ring serves as the hard alloy mechanical sealing ring, utilization of the overall material of the composite ring can be optimized; the preparation method of the hard alloy mechanical sealing ring is more practical and is matched with a composite ring to form the hard alloy mechanical sealing ring, single sintering of an upper-layer ring sintering body and combined sintering of the upper-layer ring sintering body relative to a lower-layer ring can be achieved in sequence, overall preparation of the composite ring can be achieved through one-time operation, practicability and convenience are high, and the method comprises the composite ring; the composite ring comprises an upper-layer ring sintered body and a lower-layer ring, the upper-layer ring sintered body is composed of WC-Ni-Si-B alloy, the upper-layer ring sintered body and the lower-layer ring are connected into a whole through a joint layer, a protruding ring is arranged at the bottom end of the upper-layer ring sintered body, an annular groove is formed in the top end of the lower-layer ring, and the joint layer is inserted and stored in the annular groove.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical sealing rings, and in particular to a hard alloy mechanical sealing ring and a preparation method thereof. Background Art

[0002] As we all know, cemented carbide mechanical seal rings are widely used in various pumps, reactors, compressors and other equipment in petrochemical, oil refining, pharmaceutical, papermaking and electric power industries. They play a vital role in preventing medium leakage and ensuring the safe operation of equipment. In order to facilitate the preparation of cemented carbide mechanical seal rings, we propose a cemented carbide mechanical seal ring and its preparation method.

[0003] After searching, the invention patent with Chinese patent publication number CN107116338B and the invention patent with publication number CN107541694B respectively disclose a laser composite treatment method for a sealing surface and a method for preparing a lubricating and anti-wear coating on the surface of a dynamic sealing ring. The laser composite treatment method for a sealing surface is roughly described as the following steps: a layer of hard alloy layer is clad on the sealing surface by laser cladding technology, and then the clad sealing surface is fine-machined to achieve the required surface roughness and geometric accuracy, and then the sealing surface is partitioned and heterogeneous bionic micro-molding is performed on the sealing surface, that is, the sealing surface area prone to erosion is processed by laser to produce a drag-reducing bionic micro-molding, and the sealing surface area prone to wear is processed to produce a wear-reducing bionic micro-molding. A method for preparing a lubricating and anti-wear coating on the surface of a dynamic sealing ring is described as the following steps: a layer of hard alloy layer is clad on the sealing surface by laser cladding technology, and then the cladding sealing surface is fine-machined to achieve the required surface roughness and geometric accuracy, and then the sealing surface is partitioned and heterogeneous bionic micro-molding is performed on the sealing surface. That is, the sealing surface area prone to erosion is processed by laser to produce a drag-reducing bionic micro-molding, and the sealing surface area prone to wear is processed to produce a wear-reducing bionic micro-molding. The method for preparing a lubricating and anti-wear coating is generally described as follows: [1]: before spraying, the surface of the dynamic seal ring is pretreated by degreasing, sandblasting, cleaning and natural drying; [2]: cemented carbide powder and graphite powder are weighed according to a certain ratio, the two powders are placed in a mechanical mixer and mixed to obtain a spray powder, the fluidity of the spray powder is measured, and the spray powder that meets the requirements is sprayed on the surface of the dynamic seal ring by supersonic flame spraying technology to obtain a spray coating; [3]: the dynamic seal ring after spraying is heat treated to reduce the internal stress of the coating and the interface stress of the coating / substrate, and cooled in the furnace; and [4]: ​​the wear-resistant coating on the surface of the dynamic seal ring is mechanically processed until the coating surface is flat and bright, and the surface roughness of the coating is controlled.

[0004] Although the above two existing technical solutions can respectively realize the preparation of the sealing surface and the preparation of the lubricating and anti-wear coating on the surface of the dynamic sealing ring, the dynamic sealing rings used in the latter are all one-piece structures made of the same material, and the effective utilization rate of the material needs to be further optimized. The former requires the use of laser composite technology for point-by-point processing, and the operating efficiency needs to be further improved and the practicality needs to be further enhanced. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a cemented carbide mechanical sealing ring, which adopts a separate upper ring sintered body and a lower ring to form a composite ring. Under the premise of ensuring the application of the composite ring as a cemented carbide mechanical sealing ring, the utilization of the overall material of the composite ring can be optimized. At the same time, a more practical method for preparing a cemented carbide mechanical sealing ring is provided with a matching composite ring. The method can successively realize the sintering of the upper ring sintered body monomer and the combined sintering of the upper ring sintered body with respect to the lower ring. The overall preparation of the composite ring can be achieved through a single operation, and the practicability and convenience are both strong.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a cemented carbide mechanical sealing ring, comprising a composite ring, the composite ring comprising an upper ring sintered body and a lower ring, the upper ring sintered body is composed of a WC-Ni-Si-B alloy, the upper ring sintered body and the lower ring are connected as a whole through a bonding layer, a raised ring is arranged at the bottom end of the upper ring sintered body, an annular groove is arranged at the top end of the lower ring, the annular groove matches the raised ring, the annular groove is used for inserting and storing the bonding layer, a plurality of outer grooves and a plurality of inner grooves are arranged in the lower ring, the plurality of outer grooves are respectively connected with the plurality of inner grooves, a plurality of insertion columns are arranged at the bottom end of the raised ring, the insertion columns match the outer groove, a one-way groove is arranged at the notch position of the outer groove, and an inner step groove is arranged at the bottom end of the raised ring.

[0007] Preferably, the composition of the WC-Ni-Si-B alloy mainly includes 65%-85% tungsten carbide, 10%-30% nickel, 1%-3% silicon (Si) and 1%-5% boron carbide (B4C).

[0008] Preferably, the depth of the inner groove is the same as the depth of the outer groove, and the depth of the inner groove and the outer groove is between 1 / 2 and 2 / 3 of the height of the lower ring.

[0009] Preferably, the angle between the slope surface of the one-way groove and the horizontal plane is between 40° and 50°.

[0010] Preferably, a plurality of the insertion columns are each provided with a recessed groove.

[0011] A method for preparing a cemented carbide mechanical sealing ring comprises the following steps: S1. Prepare the lower ring in advance, insert a mold with matching diameter into the outer groove, and then lay the powder of the bonding layer in the annular groove. During the laying process of the powder of the bonding layer, it is necessary to form compaction relative to the mold, and keep the powder without the bonding layer at the groove of the outer groove, that is, the powder of the bonding layer does not enter the inner groove and the outer groove, and only fills the one-way groove. After the powder of the bonding layer in the one-way groove is compacted, pull out the mold; S2, pre-prepare the upper ring sintered body, use WC-Ni-Si-B alloy powder to pre-press the upper ring sintered body blank, and place the blank relative to the lower ring after preparation. During the placement of the blank, the inner ring of the raised ring is inserted into the inner ring surface of the annular groove, and the bottom end of the inserted column is supported on the powder of the bonding layer in the single-row groove, completing the preparatory work before firing the blank and the lower ring; S3, placing the whole structure consisting of the powder of the bonding layer, the blank and the lower ring after the preparation work into a vacuum furnace, and heating it in the vacuum furnace within the temperature range of 1050°C-1150°C for 15-60 minutes to ensure the sintering of the blank to form an upper ring sintered body, and the melting and diffusion of the powder of the bonding layer between the upper ring sintered body and the lower ring, so as to achieve mutual fusion connection between the upper ring sintered body and the lower ring, and diffusion connection of the bonding layer formed at the interface between the upper ring sintered body and the lower ring; S4. During the diffusion bonding process, since the powder of the bonding layer in the one-way groove has not yet melted, it can support the inserted column, and the bottom surface of the raised ring is gradually raised from the inside to the outside, so in the early stage of vacuum furnace sintering, there is a certain gap between the upper ring sintered body and the lower ring, forming a good heating space for the upper ring sintered body in the vacuum furnace, ensuring the sintering quality of the upper ring sintered body; S5. As the sintering time goes by, the upper ring sintered body is gradually sintered, and in this process, the powder of the bonding layer in the annular groove is gradually melted. The solution generated during the melting of the powder of the bonding layer will flow into the inner groove and the outer groove under the trend of gravity, and as the powder of the bonding layer melts into a liquid state, the powder of the bonding layer in the one-way groove will be completely melted. When the powder of the bonding layer in the one-way groove cannot act on the inserted column to form a support, the inserted column will first slide into the outer groove under the guidance of the one-way groove, and then be inserted relative to the outer groove; S6. During the relative insertion of the insertion column relative to the outer groove, the height of the raised ring is reduced. During the relative insertion of the raised ring, the outer ring surface of the raised ring is relatively contacted with the annular groove. After that, a relative seal is formed between the annular groove and the raised ring. After that, as the insertion column continues to be inserted relative to the outer groove, the melted bonding layer in the annular groove overflows into the inner step groove. S7. After the vacuum furnace sintering is completed, the composite ring formed by sintering is cooled. After the cooling is completed, the melted powder of the bonding layer will solidify into one body to form a bonding layer, and the solidified bonding layer will form a fixed connection with the upper ring sintered body and the lower ring.

[0012] Compared with the prior art, the present invention provides a cemented carbide mechanical seal ring and a preparation method thereof, which have the following beneficial effects: (1) In the present invention, through the design of the composite ring, the utilization of the entire material of the composite ring can be optimized while ensuring the application of the composite ring as a cemented carbide mechanical sealing ring.

[0013] (2) In the present invention, a method for preparing a cemented carbide mechanical sealing ring is used to form a corresponding sintering method for forming a matching composite ring, which can successively realize the sintering of the upper ring sintered body and the combined sintering of the upper ring sintered body with respect to the lower ring. The overall preparation of the composite ring can be achieved through a single operation, and the practicality and convenience are both strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a flow chart of the preparation method of the present invention; Figure 2 It is a schematic diagram of a three-dimensional structure of a partially cutaway view of a composite ring of the present invention; Figure 3 It is a schematic diagram of the three-dimensional structure of the composite ring of the present invention; Figure 4 It is a schematic diagram of the exploded three-dimensional structure of the upper ring sintered body, the bonding layer powder and the lower ring cooperating with each other in the present invention; Figure 5 It is a schematic diagram of the exploded three-dimensional structure of the upper ring sintered body and the lower ring cooperating with each other in the present invention; Figure 6 It is a schematic diagram of the exploded cross-sectional three-dimensional structure of the upper ring sintered body and the lower ring cooperating with each other in the present invention; Figure 7 Another schematic diagram of a cross-sectional three-dimensional structure of the upper ring sintered body and the lower ring cooperating with each other in the present invention; Figure 8 It is a schematic diagram of an exploded bottom-up three-dimensional structure of the upper ring sintered body and the lower ring cooperating with each other in the present invention; Fig. 9 The optical photograph is of the diffusion connection state of the bonding layer between the lower floating ring and the upper floating ring sintered body of the composite ring prepared by the present invention.

[0015] In the figure: 1, upper ring sintered body; 2, lower ring; 3, bonding layer; 4, raised ring; 5, annular groove; 6, outer groove; 7, inner groove; 8, inserted column; 9, one-way groove; 10, inner step groove; 11, recessed groove. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0017] See also Figure 1-Figure 9 A cemented carbide mechanical sealing ring comprises a composite ring, the composite ring comprising an upper ring sintered body 1 and a lower ring 2, the upper ring sintered body 1 is composed of a WC-Ni-Si-B alloy, the composition of the WC-Ni-Si-B alloy mainly comprises 65%-85% of tungsten carbide, 10%-30% of nickel, 1%-3% of silicon (Si) and 1%-5% of boron carbide (B4C), the upper ring sintered body 1 and the lower ring 2 are connected as a whole through a bonding layer 3, a raised ring 4 is arranged at the bottom end of the upper ring sintered body 1, an annular groove 5 is arranged at the top end of the lower ring 2, the annular groove 5 matches the raised ring 4, and the annular groove 5 is used for inserting and storing the bonding layer 3, a plurality of outer grooves 6 and a plurality of inner grooves 7 are arranged in the lower ring 2, the plurality of outer grooves 6 are respectively connected with the plurality of inner grooves 7, the depth of the inner groove 7 and the depth of the outer groove 6 are The inner groove 7 and the outer groove 6 have the same depth, and the depth of the inner groove 7 and the outer groove 6 is between 1 / 2 and 2 / 3 of the height of the lower ring 2. A plurality of insert columns 8 are provided at the bottom end of the raised ring 4, and the insert columns 8 match the outer groove 6. A one-way groove 9 is provided at the notch position of the outer groove 6, and the angle between the slope surface of the one-way groove 9 and the horizontal plane is between 40° and 50°. An inner step groove 10 is provided at the bottom end of the raised ring 4, and a plurality of insert columns 8 are provided with recessed grooves 11. Through the design of the composite ring, the utilization of the overall material of the composite ring can be optimized while ensuring the application of the composite ring as a cemented carbide mechanical sealing ring. The upper ring sintered body 1 is made of a material with a more expensive cost and better properties, and the lower ring 2 is made of a common and low-cost material such as stainless steel or ordinary steel, thereby realizing an optimized configuration of the overall material of the composite ring.

[0018] In summary, the preparation method of the cemented carbide mechanical seal ring includes the following steps: first, the lower ring 2 is prepared in advance, a mold with a matching diameter is inserted into the outer groove 6, and then the powder of the bonding layer 3 is laid in the annular groove 5. During the laying process of the powder of the bonding layer 3, it is necessary to form a compaction relative to the mold, and keep the powder of the bonding layer 3 at the groove of the outer groove 6, that is, the powder of the bonding layer 3 does not enter the inner groove 7 and the outer groove 6, and only fills the one-way groove 9. At this time, the powder of the bonding layer 3 is as attached. Figure 4As shown in the raised portion of the annular groove 5 shown in the figure, after the powder of the bonding layer 3 in the one-way groove 9 is compacted, the mold is pulled out, and the upper ring sintered body 1 is prepared in advance. The upper ring sintered body 1 is pre-pressed with the powder of the WC-Ni-Si-B alloy. After the preparation is completed, the blank is placed relative to the lower ring 2. During the placement of the blank, the inner ring of the raised ring 4 is inserted into the inner ring surface of the annular groove 5, and the bottom end of the inserted column 8 is supported on the powder of the bonding layer 3 in the one-way groove, completing the preparatory work before firing the blank and the lower ring 2. After that, the integral structure composed of the powder of the bonding layer 3, the blank and the lower ring 2 that have completed the preparatory work is placed in a vacuum furnace and heated in the vacuum furnace within a temperature range of 1050°C-1150°C for 15 minutes. -60 minutes to ensure the sintering of the blank to form the upper ring sintered body 1, and the melting and diffusion of the powder of the bonding layer 3 between the upper ring sintered body 1 and the lower ring 2, so as to achieve the mutual fusion connection between the upper ring sintered body 1 and the lower ring 2, and the diffusion connection of the bonding layer 3 formed at the interface between the upper ring sintered body 1 and the lower ring 2. In the diffusion connection process, since the powder of the bonding layer 3 in the one-way groove 9 has not yet melted, it can form support for the inserted column 8, and the bottom surface of the raised ring 4 is gradually rising from the inside to the outside, so in the initial stage of sintering in the vacuum furnace, there is a certain gap between the upper ring sintered body 1 and the lower ring 2, forming a good heating space for the upper ring sintered body 1 in the vacuum furnace, thereby ensuring the sintering quality of the upper ring sintered body 1.

[0019] Furthermore, with the passage of sintering time, the upper ring sintered body 1 is gradually sintered, and in this process, the powder of the bonding layer 3 in the annular groove 5 is gradually melted. The solution generated during the melting of the powder of the bonding layer 3 will flow into the inner groove 7 and the outer groove 6 under the trend of gravity, and as the powder of the bonding layer 3 melts into a liquid state, the powder of the bonding layer 3 in the one-way groove 9 will be completely melted. When the powder of the bonding layer 3 in the one-way groove 9 cannot act on the inserted column 8 to form a support, the inserted column 8 will first slide into the outer groove 6 under the guidance of the one-way groove 9, and then be inserted relative to the outer groove 6. In the process of the insertion column 8 being relatively inserted relative to the outer groove 6, the convex The height of the raised ring 4 is reduced. During the process of reducing the height of the raised ring 4, the outer ring surface of the raised ring 4 will form a relative contact insertion with the annular groove 5. Thereafter, a relative seal will be formed between the annular groove 5 and the raised ring 4. Thereafter, as the insertion column 8 continues to be inserted relative to the outer groove 6, the melted bonding layer 3 in the annular groove 5 will overflow into the inner step groove 10. After the vacuum furnace sintering is completed, the sintered composite ring is cooled. After the cooling is completed, the powder of the melted bonding layer 3 will solidify into one to form a bonding layer 3, and the solidified bonding layer 3 will solidify into the annular groove 5, the inner step groove 10 and the inner groove 7 respectively, so as to realize the fixed connection between the upper ring sintered body 1 and the lower ring 2. Figure 2The cross-sectional view shown in FIG. 1 shows that the bonding layer 3 is solidified in the annular groove 5, the inner step groove 10 and the inner groove 7. Fig. 9 It can be seen that the bonding layer 3 is melted and diffused between the upper ring sintered body 1 and the lower ring 2 in the actual preparation.

[0020] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A cemented carbide mechanical seal ring, characterized in that: The composite ring comprises an upper ring sintered body (1) and a lower ring (2), wherein the upper ring sintered body (1) is composed of a WC-Ni-Si-B alloy, the upper ring sintered body (1) and the lower ring (2) are connected as a whole via a bonding layer (3), a raised ring (4) is arranged at the bottom end of the upper ring sintered body (1), an annular groove (5) is arranged at the top end of the lower ring (2), the annular groove (5) matches the raised ring (4), and the The annular groove (5) is used for inserting and storing the bonding layer (3); a plurality of outer grooves (6) and a plurality of inner grooves (7) are arranged in the lower ring (2); the plurality of outer grooves (6) are respectively connected to the plurality of inner grooves (7); a plurality of insertion columns (8) are arranged at the bottom end of the raised ring (4); the insertion columns (8) match the outer grooves (6); a one-way groove (9) is arranged at the notch position of the outer groove (6); and an inner step groove (10) is arranged at the bottom end of the raised ring (4).

2. A cemented carbide mechanical seal ring according to claim 1, characterized in that: The WC-Ni-Si-B alloy mainly comprises 65%-85% of tungsten carbide, 10%-30% of nickel, 1%-3% of silicon and 1%-5% of boron carbide.

3. A cemented carbide mechanical seal ring according to claim 1, characterized in that: The depth of the inner groove (7) is the same as the depth of the outer groove (6), and the depth of the inner groove (7) and the outer groove (6) is between 1 / 2 and 2 / 3 of the height of the lower ring (2).

4. A cemented carbide mechanical seal ring according to claim 1, characterized in that: The angle between the slope surface of the one-way groove (9) and the horizontal plane is between 40° and 50°.

5. A cemented carbide mechanical seal ring according to claim 1, characterized in that: A plurality of the insertion columns (8) are each provided with a recessed groove (11).

6. A method for preparing a cemented carbide mechanical seal ring, characterized in that: A cemented carbide mechanical seal ring according to any one of claims 1 to 5 is used, comprising the following steps: S1, pre-preparing the lower ring (2), inserting a mold with a matching diameter into the outer groove (6), and then laying the powder of the bonding layer (3) in the annular groove (5). During the laying operation of the powder of the bonding layer (3), it is necessary to form a compaction relative to the mold, and to keep the powder of the bonding layer (3) at the groove of the outer groove (6), that is, the powder of the bonding layer (3) does not enter the inner groove (7) and the outer groove (6), and only fills the one-way groove (9). After the powder of the bonding layer (3) in the one-way groove (9) is compacted, the mold is pulled out; S2, pre-preparing an upper ring sintered body (1), using WC-Ni-Si-B alloy powder to pre-press a blank of the upper ring sintered body (1), and placing the blank relative to the lower ring (2) after preparation. During the placement of the blank, the inner ring of the raised ring (4) is inserted into the inner ring surface of the annular groove (5), and the bottom end of the inserted column (8) is supported on the powder of the bonding layer (3) in the single-row groove, thereby completing the preparatory work before firing the blank and the lower ring (2); S3, placing the whole structure consisting of the powder of the bonding layer (3) that has completed the preparation work, the blank and the lower ring (2) into a vacuum furnace, and heating it in the vacuum furnace within a temperature range of 1050°C-1150°C for 15-60 minutes to ensure that the blank is sintered to form an upper ring sintered body (1), and the powder of the bonding layer (3) between the upper ring sintered body (1) and the lower ring (2) is melted and diffused, so that the upper ring sintered body (1) and the lower ring (2) are fused and connected with each other, and the bonding layer (3) formed at the interface between the upper ring sintered body (1) and the lower ring (2) is diffusely connected; S4. After the vacuum furnace sintering is completed, the composite ring formed by sintering is cooled. After the cooling is completed, the melted powder of the bonding layer (3) solidifies into one body to form a bonding layer (3), and the solidified bonding layer (3) forms a fixed connection with respect to the upper ring sintered body (1) and the lower ring (2).

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