Slag locking valve sealing surface strengthening method and slag locking valve sealing surface

Abstract

The invention discloses a method for strengthening a sealing surface of a lock slag valve. The method comprises the following steps: step 1, pretreating the sealing surfaces of a valve core and a valve seat; 2, nitriding treatment is conducted on the valve element and the valve seat through in-light nitriding treatment so that nitriding layers can be formed on the sealing faces of the valve element and the valve seat; 3, a diamond coating is deposited on the surface of the nitriding layer through vapor deposition, a layer of nitride is directly generated on the surface of the valve element base material and the surface of the valve seat base material through a chemical reaction, a bonding surface does not exist, the cracking and falling risks are avoided, and the formed chromium nitride layer has a good anti-corrosion effect; the hardness of the diamond coating can reach more than 2600Hv, the wear resistance is multiplied, the friction coefficient of the diamond coating is low, the opening and closing torque of the valve can be greatly reduced, the service life of the lock slag valve can be prolonged, and the reliability of the lock slag valve can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of slag lock valves, and in particular to a slag lock valve sealing surface strengthening method and a slag lock valve sealing surface. Background Art

[0002] The slag lock valve is a ball valve for opening and closing slag discharge on the coal chemical gasification device. The working environment is very harsh. The content of coal slag particles in the flowing medium is high, the hardness of coal slag particles is large, the medium temperature is high, and the corrosiveness is strong. At present, the conventionally used slag lock valve generally adopts supersonic spraying of tungsten carbide to strengthen the contact surface of the valve core and valve seat. This treatment method has been widely used in hard-sealed ball valves due to its good economy. However, practice has proved that the supersonic spraying of tungsten carbide strengthening treatment method is not suitable for coal chemical slag lock valves, which is easy to cause coating peeling and seal failure. The main reason is that the supersonic spray coating bonding surface is a physical bond, which will crack and fall off under the alternating changes of high temperature and cold. In addition, due to the pores in the supersonic spray coating, the corrosive medium will corrode the valve core and valve seat substrate through the pores. The volume expansion during the corrosion process causes the coating to crack and fall off at the pores. Summary of the invention

[0003] The object of the present invention is to provide a slag lock valve sealing surface strengthening method and a slag lock valve sealing surface to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A method for strengthening the sealing surface of a slag lock valve comprises the following steps:

[0006] Step 1: Pre-treat the sealing surface of the valve core and valve seat substrate;

[0007] Step 2: Perform nitriding treatment on the valve core and the valve seat by light nitriding treatment to form a nitrided layer on the sealing surface of the valve core and the valve seat;

[0008] Step 3: forming a diamond coating on the surface of the nitride layer by vapor deposition.

[0009] As a further solution of the present invention: the valve core and valve seat substrates are made of duplex stainless steel.

[0010] As a further solution of the present invention: the valve core and valve seat substrates are subjected to solution treatment, and then fine machining is performed after the solution treatment. Polishing is performed before and after light nitriding, and light nitriding adopts segmented nitriding.

[0011] As a further solution of the present invention: the segmented nitriding includes three stages, the first stage is heated to 250-300°C and kept warm for 45-50 minutes; the second stage is heated to 500-550°C and kept warm for 45-50 minutes; the third stage is heated to 750-800°C and kept warm for 28-30 hours.

[0012] As a further solution of the present invention: the depth of the nitride layer is not less than 180 microns, and the hardness of the nitride layer is not less than 1200 Hv.

[0013] As a further solution of the present invention: the thickness of the diamond coating is 5-10 microns, and the hardness of the diamond coating is not less than 2500 Hv.

[0014] As a further solution of the present invention: the vapor deposition in step 3 comprises the following steps:

[0015] Step 3.1, polishing and cleaning pretreatment;

[0016] Step 3.2, surface activation using arc discharge plasma technology;

[0017] Step 3.3: Use ion sputtering technology to deposit and post-process the workpiece surface to obtain the required diamond coating.

[0018] A sealing surface of a slag lock valve comprises a valve core and a valve seat, wherein the valve core and the valve seat comprise a substrate and a nitride layer and a diamond layer arranged on the surface of the substrate.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention directly generates a layer of nitride on the surface of the valve core and valve seat substrate material through chemical reaction, there is no bonding surface, the risk of cracking and falling off is avoided, and the formed chromium nitride layer has a good anti-corrosion effect; the hardness of the diamond coating can reach more than 2600Hv, the wear resistance is doubled, and the friction coefficient of the diamond coating is low, which can greatly reduce the opening and closing torque of the valve, which is beneficial to improve the life and reliability of the slag lock valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the valve core structure of this embodiment;

[0021] Figure 2 This is a schematic diagram of the valve seat structure of this embodiment;

[0022] Figure 3 This is a schematic diagram of the slag lock valve structure of this embodiment;

[0023] Figure 4 Schematic diagram of the sealing surface structure of this embodiment.

[0024] In the figure: 1-valve core, 2-valve seat, 3-substrate, 4-nitride layer, 5-diamond layer. DETAILED DESCRIPTION

[0025] 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.

[0026] See also Figure 1 A slag lock valve sealing surface includes a valve core and a valve seat. The valve core and the valve seat include a substrate and a nitride layer and a diamond layer arranged on the surface of the substrate.

[0027] A method for strengthening the sealing surface of a slag lock valve comprises the following steps:

[0028] Step 1: Pre-treat the sealing surface of the valve core and valve seat substrate. The valve core and valve seat substrate are made of duplex stainless steel;

[0029] Step 2: Perform nitriding treatment on the valve core and the valve seat by light nitriding treatment to form a nitrided layer on the sealing surface of the valve core and the valve seat;

[0030] The valve core and valve seat substrates are subjected to solution treatment. After solution treatment, the mechanical properties, corrosion resistance, processing performance and thermal stability of the material can be improved, which is more conducive to the surface treatment of the material. After solution treatment, fine processing is carried out, and polishing is carried out before and after light nitriding. Light nitriding adopts segmented nitriding, which includes three stages. The first stage is heated to 250-300°C and kept warm for 45-50 minutes; the second stage is heated to 500-550°C and kept warm for 45-50 minutes; the third stage is heated to 750-800°C and kept warm for 28-30 hours.

[0031] By means of segmented nitriding, and each nitriding being more stable than the previous one, that is, step-by-step temperature increase, the nitriding effect can be improved and the hardness of the nitrided layer can be increased. In this embodiment, the depth of the nitrided layer is not less than 180 microns, and the hardness of the nitrided layer is not less than 1200 Hv.

[0032] Step 3, forming a diamond coating on the surface of the nitride layer by vapor deposition;

[0033] Vapor deposition includes the following steps:

[0034] Step 3.1, polishing and cleaning pretreatment;

[0035] Step 3.2, surface activation using arc discharge plasma technology;

[0036] Step 3.3, using ion sputtering technology to deposit and post-process on the workpiece surface to obtain the required diamond coating;

[0037] The thickness of the diamond coating is 5-10 micrometers, and the hardness of the diamond coating is not less than 2500 Hv.

[0038] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0039] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for strengthening the sealing surface of a slag lock valve, characterized in that: The following steps are involved: Step 1: pre-treating the base material sealing surfaces of the valve core (1) and the valve seat (2); Step 2: Performing a nitriding treatment on the valve core (1) and the valve seat (2) by photo-nitriding treatment to form a nitrided layer (4) on the sealing surfaces of the valve core (1) and the valve seat (2); Step 3: forming a diamond coating (5) on the surface of the nitride layer by vapor deposition.

2. A method for strengthening the sealing surface of a slag lock valve according to claim 1, characterized in that: The base materials of the valve core (1) and the valve seat (2) are made of duplex stainless steel.

3. A method for strengthening the sealing surface of a slag lock valve according to claim 1, characterized in that: The base materials (3) of the valve core (1) and the valve seat (2) are subjected to a solution treatment, and then fine machining is performed after the solution treatment. Polishing is performed before and after light nitriding, and the light nitriding adopts segmented nitriding.

4. A method for strengthening the sealing surface of a slag lock valve according to claim 3, characterized in that: The segmented nitriding includes three stages: the first stage is to heat up to 250-300°C and keep warm for 45-50 minutes; the second stage is to heat up to 500-550°C and keep warm for 45-50 minutes; the third stage is to heat up to 750-800°C and keep warm for 28-30 hours.

5. A method for strengthening the sealing surface of a slag lock valve according to claim 1, characterized in that: The depth of the nitride layer is not less than 180 micrometers, and the hardness of the nitride layer is not less than 1200 Hv.

6. A method for strengthening the sealing surface of a slag lock valve according to claim 1, characterized in that: The thickness of the diamond coating is 5-10 microns, and the hardness of the diamond coating is not less than 2500 Hv.

7. A method for strengthening the sealing surface of a slag lock valve according to claim 1, characterized in that: The vapor deposition in step 3 comprises the following steps: Step 3.1, polishing and cleaning pretreatment; Step 3.2, surface activation using arc discharge plasma technology; Step 3.3: Use ion sputtering technology to deposit and post-process the workpiece surface to obtain the required diamond coating.

8. A slag lock valve sealing surface using the strengthening method according to any one of claims 1 to 7, characterized in that: The invention comprises a valve core (1) and a valve seat (2), wherein the valve core (1) and the valve seat (2) comprise a substrate (3) and a nitride layer (4) and a diamond layer (5) arranged on the surface of the substrate (3).

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