Chapter C: Valve stem
The valve stem bearing the tensile, compressive and torsional forces while the valve opening and closing. The valve stem could contact with media directly, and could also have relevant friction movement against valve packing. So, the material used for valve stem has to be sufficient strength and toughness under certain required temperature. And also has to be anti-corrosion, scratch resistance, and good manufacturability.
Chapter E: Valve stems Nut, Fastener, Packing, Valve Bonnet Gasket
Stem nut bearing axial while opening and closing the valve, the material used for stem nut has to be sufficient strength. and the nut screw drive with the stem，it has to be low friction coefficient and antirust as well.
Fastener, Packing, Valve Bonnet Gasket
Fastener including bolts, studs and nuts. Fasteners bearing pressure on valve directly, and it is crucial importance to prevent media leaking, so the materials has to be sufficient strength and toughness under certain required temperature
2. Valve packing
The valve packing is used to fill the space between valve bonnet and packing room, to prevent the media leaking through the stem and packing space. So, the material has to be
1) Good corrosion resistance
2) Good sealing
3) Low friction coefficient
3. Valve Bonnet Gasket
Gasket is used to fill the joint surface (For example: between body and bonnet sealing surface) to prevent media leaking from the joint surfaces. So, the material has to be
Good elasticity and plasticity, and has to be sufficient strength to ensure the sealing, and also require to be corrosion resistance.