Valves are control components in pipeline fluid transport systems, used to change the cross-section of the channel and the direction of medium flow, and have functions such as diversion, shut-off, throttling, check valve, and flow diversion. Human-caused damage is caused by improper design, manufacturing, material selection, installation, use, and maintenance. Natural damage refers to the wear of valves under normal operating conditions, as well as damage caused by the unavoidable corrosion and erosion of the sealing surface by the medium. Next, we will introduce in detail the main causes of valve sealing surface damage.

Specific causes are as follows:

1. Improper installation and poor maintenance can lead to abnormal operation of the sealing surface, premature damage.

2. Damage caused by improper selection and operation. This mainly manifests as not selecting valves according to the operating conditions, using shut-off valves as throttling valves, resulting in excessive sealing pressure, excessively fast or incomplete sealing, and corrosion and wear of the sealing surface.

3. Poor processing quality of the sealing surface: This mainly manifests as cracks, porosity, and ballast defects on the sealing surface. These defects are caused by improper selection of welding and heat treatment specifications and improper operation during welding and heat treatment. Excessive or insufficient hardness of the sealing surface is caused by incorrect material selection or improper heat treatment. Uneven hardness and corrosion resistance of the sealing surface are mainly due to the bottom metal being inflated during welding, diluting the alloy composition of the sealing surface. Design issues also play a role.

4. Mechanical damage: such as scratches, impacts, and compression damage. During the opening and closing of the sealing surface, atoms interpenetrate and adhere between the two sealing surfaces under high temperature and pressure. When the two sealing surfaces move relative to each other, the adhesion is easily torn apart. The higher the roughness of the sealing surface, the more likely this phenomenon will occur. When the valve is closed and the valve disc returns, the sealing surface will be scratched and compressed, leading to localized wear or indentation.

5. Media erosion is the result of wear, scouring, and cavitation of the sealing surface as the media moves. At a certain speed, suspended particles in the media collide with the sealing surface, causing localized damage. High-speed moving media directly washes the sealing surface, causing localized damage. When the media mixes and partially evaporates, bubbles burst and impact the sealing surface, leading to localized damage. The alternating effects of media erosion and chemical erosion can severely corrode the sealing surface. 6. Electrochemical corrosion: Contact between sealing surfaces, contact between the sealing surface and the sealing body/valve body, and differences in media concentration and oxygen concentration can all generate potential differences and electrochemical corrosion, leading to corrosion of the side sealing surfaces.

7. Chemical corrosion by the media: Without generating an electric current, the media reacts directly with the sealing surface, corroding it.

Through the detailed explanation above, you should now have a better understanding of the main causes of valve sealing surface damage. We hope this information will help you better prevent valve damage!