Sealing surface is the key working surface of the valve. The quality of sealing surface is related to the service life of the valve. Generally, the sealing surface materials of excavator casting suppliers should consider corrosion resistance, scratch resistance, erosion resistance, oxidation resistance other factors. There are usually two categories:

Excavator casting wholesale (I) soft materials 1. Rubber (including butadiene rubber, fluororubber, etc.) 2. Plastic (polytetrafluoroethylene, nylon, etc.)

（2） Hard sealing materials 1. Copper alloy (for low pressure valve) 2. Chromium stainless steel (for ordinary high medium pressure valve) 3. Stellite alloy (for high temperature high pressure valve strongly corrosive valve) 4. Nickel base alloy (for corrosive medium)

In the process of valve opening closing, the valve stem bears the pulling, pressing twisting forces, is in direct contact with the medium. At the same time, there is relative friction movement between the valve stem the packing. Therefore, the valve stem material must have sufficient strength, impact toughness, corrosion resistance, abrasion resistance good process performance under the specified temperature. Commonly used stem materials are as follows.