The sealing performance of the valve directly affects the control effect of the fluid medium and the safe operation of the system, the valve sealing surface grinding is to ensure its sealing performance is one of the important means of its main purpose is to eliminate the unevenness of the sealing surface, defects and particles, to improve the surface flatness and roughness, so as to achieve the best sealing performance. After grinding the valve sealing surface can usually achieve dimensional accuracy of 0.001~0.003mm, geometric accuracy (such as unevenness) of 0.001mm, surface roughness of 0.1~0.008.

The basic principle of grinding

1. Grinding process grinding

During the grinding process, the grinding tool and the sealing ring surface is well adhered together, the grinding tool along the adhering surface for complex grinding movement. The grinding tool and sealing ring surface put between the abrasive, when the grinding tool and sealing ring surface relative movement, part of the abrasive in the abrasive in the grinding tool and sealing ring surface sliding or rolling, cut off the sealing ring surface of a very thin layer of metal. Grinding is not only a mechanical process of abrasives on metal, but also has a chemical effect. The oil and grease in the abrasive can make the processed surface form an oxide film, thus accelerating the grinding process.

2. Grinding motion

Grinding tool and sealing ring surface relative movement, each point on the sealing ring surface of the relative sliding distance of the grinding tool should be the same, and, the direction of the relative movement should be constantly changing. This kind of movement avoids the abrasive particles repeating their own trajectory on the seal surface, reduces the obvious abrasion marks, and thus reduces the roughness of the seal surface.

3. Grinding speed

The speed of grinding directly affects the grinding efficiency. Grinding speed is usually 10~240m/min, but the high precision requirements of the workpiece, the grinding speed is generally not more than 30m/min. valve sealing surface grinding speed and sealing surface materials, different materials sealing surface has different recommended grinding speed.

4. Grinding pressure

Grinding efficiency with the increase in grinding pressure and improve, but the grinding pressure can not be too large, generally 0.01 ~ 0.4MPa. Rough grinding to take a larger value, fine grinding to take a smaller value.

5. Grinding allowance

As grinding is a finishing process, the cutting amount is very small. The size of the grinding allowance depends on the machining accuracy and surface roughness of the previous process. In order to ensure the removal of traces of the previous process and the correction of the seal geometry error under the premise of the smaller the grinding allowance, the better.

Grinding method steps

Preparation: Confirm the type and structure of the valve, check the valve sealing surface damage and surface roughness. At the same time, prepare grinding tools, grinding materials and the appropriate lubricant. Clean the surface: use the appropriate cleaning agent to clean the sealing surface to remove surface dirt and grease, to ensure the accuracy of the grinding effect.

Selection of grinding tools: According to the shape and material of the valve sealing surface, select the appropriate grinding tools, such as grinding wheels, abrasive discs, etc..

Grinding operation: fix the grinding tool on the appropriate grinding equipment, according to the shape of the sealing surface of the valve and the damage, the appropriate grinding operation. It can be operated manually or mechanically assisted.

Grinding degree control: according to the actual situation, control the degree of grinding, generally should ensure that the valve sealing surface of the flat.