Method for spraying wolfram carbide alloy on seal surface of valve plate (seat) at supersonic speed

Abstract

The invention discloses a method for spraying a wolfram carbide alloy on a seal surface of a valve plate (seat) at a supersonic speed. The method is characterized in that supersonic spraying equipment is adopted to spray the wolfram carbide alloy on the seal surface of the valve plate (seat); the sprayed wolfram carbide alloy coating is dense and meets the airtightness requirement; the coating hardness HV (Vickers hardness) is not less than 1100; the coating void ratio is not more than 1%; the coating bonding strength is not less than 10000PSi; and the coating thickness is more than 0.15mm. The method has the following advantages: through supersonic spraying, the coating and a matrix structure are not subjected to high temperature and deformation; preheating and postweld heat treatment are not needed; lathing is not needed after welding; the method is suitable for batch (non-singleton) production; and the production efficiency is high.

Description

technical field

[0001] The invention relates to a high-pressure valve, in particular to a method for supersonic spraying of tungsten carbide alloy on the sealing surface of a valve plate (seat). Background technique

[0002] In the production of domestic high-pressure valves, in order to improve the service life of the valve products, especially the anti-scratch and erosion resistance of the sealing surface of the valve plate (seat), it is generally sprayed on the valve plate (seat) body with nickel-based alloy or Surfacing cobalt-based alloys, although the equipment and technology are continuously improved, but due to the high temperature of surfacing or spray welding, the hardness of the matrix is ​​changed and the matrix structure is destroyed. Generally, preheating is required before welding, and corresponding heat treatment is required after welding. , Low production efficiency. Contents of the invention

[0003] The purpose of the present invention is to provide a m...

Examples

Embodiment 1

[0014] Supersonic spraying tungsten carbide alloy coating on the sealing surface of the valve plate (seat) according to the following steps: workpiece cleaning, surface sandblasting, spraying, rough grinding, visual inspection, fine grinding, polishing, inspection and storage, characterized in that: Among them , the workpiece needs to be sandblasted before spraying, and the workpiece after sandblasting should be avoided from touching; the workpiece should be clamped with a tooling fixture before spraying, and there is no need to use high-temperature protection or low-temperature protection on the sprayed surface. Tungsten carbide alloy powder is selected, and the powder is heated at 85°C before use. Fully bake, control the oxygen flow rate at 2200 SCFH, kerosene flow rate at 6.5, powder feeding air flow rate at 30 SCFH, and control the interval between each spraying at 20 minutes.

Embodiment 2

[0016] Supersonic spraying tungsten carbide alloy coating on the sealing surface of the valve plate (seat) according to the following steps: workpiece cleaning, surface sandblasting, spraying, rough grinding, visual inspection, fine grinding, polishing, inspection and storage, characterized in that: Among them , the workpiece needs to be sandblasted before spraying, and the workpiece after sandblasting should be avoided from touching; the workpiece should be clamped with a tooling fixture before spraying, and there is no need to use high-temperature protection or low-temperature protection on the sprayed surface. Tungsten carbide alloy powder is selected, and the powder is heated at 85°C before use. Fully bake, control the oxygen flow rate at 2000SCFH, kerosene flow rate at 5.5, powder feeding air flow rate at 20SCFH, and control the interval of each spraying at 20 minutes.

Embodiment 3

[0018] Supersonic spraying tungsten carbide alloy coating on the sealing surface of the valve plate (seat) according to the following steps: workpiece cleaning, surface sandblasting, spraying, rough grinding, visual inspection, fine grinding, polishing, inspection and storage, characterized in that: Among them , the workpiece needs to be sandblasted before spraying, and the workpiece after sandblasting should be avoided from touching; the workpiece should be clamped with a tooling fixture before spraying, and there is no need to use high-temperature protection or low-temperature protection on the sprayed surface. Tungsten carbide alloy powder is selected, and the powder is heated at 85°C before use. Fully bake, control the oxygen flow rate at 2100SCFH, kerosene flow rate at 6.0, powder feeding air flow rate at 25SCFH when spraying, and control the interval between each spraying at 20 minutes.

[0019] Coating hardness of the tungsten carbide alloy coating in Examples 1-3: HV≥11...

technical field

[0001] The invention relates to a high-pressure valve, in particular to a method for supersonic spraying of tungsten carbide alloy on the sealing surface of a valve plate (seat). Background technique

[0002] In the production of domestic high-pressure valves, in order to improve the service life of the valve products, especially the anti-scratch and erosion resistance of the sealing surface of the valve plate (seat), it is generally sprayed on the valve plate (seat) body with nickel-based alloy or Surfacing cobalt-based alloys, although the equipment and technology are continuously improved, but due to the high temperature of surfacing or spray welding, the hardness of the matrix is ​​changed and the matrix structure is destroyed. Generally, preheating is required before welding, and corresponding heat treatment is required after welding. , Low production efficiency. Contents of the invention

[0003] The purpose of the present invention is to provide a m...

Examples

Embodiment 1

[0014] Supersonic spraying tungsten carbide alloy coating on the sealing surface of the valve plate (seat) according to the following steps: workpiece cleaning, surface sandblasting, spraying, rough grinding, visual inspection, fine grinding, polishing, inspection and storage, characterized in that: Among them , the workpiece needs to be sandblasted before spraying, and the workpiece after sandblasting should be avoided from touching; the workpiece should be clamped with a tooling fixture before spraying, and there is no need to use high-temperature protection or low-temperature protection on the sprayed surface. Tungsten carbide alloy powder is selected, and the powder is heated at 85°C before use. Fully bake, control the oxygen flow rate at 2200 SCFH, kerosene flow rate at 6.5, powder feeding air flow rate at 30 SCFH, and control the interval between each spraying at 20 minutes.

Embodiment 2

[0016] Supersonic spraying tungsten carbide alloy coating on the sealing surface of the valve plate (seat) according to the following steps: workpiece cleaning, surface sandblasting, spraying, rough grinding, visual inspection, fine grinding, polishing, inspection and storage, characterized in that: Among them , the workpiece needs to be sandblasted before spraying, and the workpiece after sandblasting should be avoided from touching; the workpiece should be clamped with a tooling fixture before spraying, and there is no need to use high-temperature protection or low-temperature protection on the sprayed surface. Tungsten carbide alloy powder is selected, and the powder is heated at 85°C before use. Fully bake, control the oxygen flow rate at 2000SCFH, kerosene flow rate at 5.5, powder feeding air flow rate at 20SCFH, and control the interval of each spraying at 20 minutes.

Embodiment 3

[0018] Supersonic spraying tungsten carbide alloy coating on the sealing surface of the valve plate (seat) according to the following steps: workpiece cleaning, surface sandblasting, spraying, rough grinding, visual inspection, fine grinding, polishing, inspection and storage, characterized in that: Among them , the workpiece needs to be sandblasted before spraying, and the workpiece after sandblasting should be avoided from touching; the workpiece should be clamped with a tooling fixture before spraying, and there is no need to use high-temperature protection or low-temperature protection on the sprayed surface. Tungsten carbide alloy powder is selected, and the powder is heated at 85°C before use. Fully bake, control the oxygen flow rate at 2100SCFH, kerosene flow rate at 6.0, powder feeding air flow rate at 25SCFH when spraying, and control the interval between each spraying at 20 minutes.

[0019] Coating hardness of the tungsten carbide alloy coating in Examples 1-3: HV≥11...