There are two reasons for the damaged sealing surface: damage and natural damage. Man-made damage is caused by poor design, poor workmanship, improper material selection, improper installation, improper use and improper maintenance. Natural damage refers to the wear of the valve under normal working conditions, which is the inevitable corrosion and erosion of the sealing surface caused by the medium.
The reasons for the damage of the sealing surface can be summarized into the following aspects:
The quality of edge banding is poor.
Defects such as cracks, pores, and ballast on the sealing surface are caused by improper selection of surfacing and heat treatment specifications and improper surfacing and heat treatment operations. The hardness of the sealing surface is too high or too low because of improper material selection or improper heat treatment process As a result, the gas solenoid valve on the sealing surface has uneven hardness and is not corrosion-resistant, which is mainly caused by blowing the bottom metal to the top during the surfacing process, which weakens the alloy composition of the sealing surface. Of course, there are also design issues.
Damage caused by improper selection or improper operation.
The main manifestation is that the purchased valve does not conform to the actual situation, and the high-temperature solenoid valve cut-off valve is used as a throttle valve, resulting in excessive closing pressure, too fast or not strict closing speed, and erosion and wear of the sealing surface.
Due to improper installation and poor maintenance, the seal cannot work properly.
The valve is not operating properly, prematurely damaging the sealing surface. The medium is chemically corroded. The medium around the sealing surface will directly chemically react with the sealing surface without generating current to corrode the seal.
Because the sealing surfaces are in contact with each other, the contact between the sealing surface and the closing body and the valve body, as well as the difference in medium concentration and oxygen concentration, there will be a potential difference, which will cause electrochemical corrosion, and the sealing surface on the anode side will be corroded.