Sealing and hardfacing
Filled PTFE
Glass- or carbon-filled PTFE
PTFE filled with glass fibre or carbon (RPTFE) to overcome the creep and wear weakness of virgin PTFE. The standard material for ball valve seats in higher pressure classes.
- HARDNESS
- —
- Rm · MPa (typical)
- —
- TEMPERATURE
- −200 … +260 °C
- COST
Chemical composition
PTFE matrix + filler: glass fibre (15–25%), carbon (25%), carbon-graphite or bronze.
Mechanical properties
The values in this section are being verified.
Service temperature
−200 °C+260 °C−200−1000100200300400500600700800
Same range as PTFE; less creep than virgin PTFE at high temperature. Up to 200 °C as a seat in steam.
Media suitability GENERAL TREND
Water
Steam
Mineral oil
Fuel, aliphatic HC
Ozone, outdoor
Dilute acid
Caustic
Ketones, esters
Emsal assessment. The final choice is made from corrosion tables, taking concentration, temperature, chloride content and flow velocity into account.
Strengths and weaknesses
Strengths
- Markedly lower creep and wear than virgin PTFE
- Seat tightness at higher pressure and temperature
- Retains the low friction of PTFE
Weaknesses
- Glass filler is not suitable for hydrofluoric acid and hot caustics
- Carbon filler is limited in oxidizers
- Harder: surface finish matters
Manufacturing and use
- ECONOMY
- Medium.
- MANUFACTURING METHODS
- Pressing + sintering · Turning
- TYPICAL VALVE PARTS
- Ball seat · Packing ring · Bushing
Used in 14 Emsal products
- 002Disc check valveSeal
- 070Flanged 2-piece ball valveStem seal · Seal
- 071Flanged 3-piece ball valveStem seal · Seal
- 072Flanged 3-way ball valveStem seal · Seal
- 073Flanged 4-way ball valveStem seal · Seal
- 074Threaded 2-piece ball valve with ISO 5211 mounting padStem seal · Seal
- 075Threaded 3-piece ball valve with ISO 5211 mounting padStem seal · Seal
- 076Threaded 3-way ball valve with ISO 5211 mounting padSeal · O-ring
- 078Threaded 2-piece ball valveSeal
- 079Threaded 3-piece ball valveSeal
- 080Wafer ball valveSeal
- 086Threaded mini ball valveSeal
- 112High-performance butterfly valveValve seat
- 171Socket weld cryogenic globe valveSeal · Stem seal
Source: ASTM D4745. Values compiled and verified by Emsal Vana; for binding values, refer to the current edition of the standard and the material certificate.