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Zhongchi
Zhongchi
Zhongchi
Zhongchi
Zhongchi
Zhongchi
Zhongchi
Zhongchi
Zhongchi
In China, the designation of sealing face materials in JB/T 308 is as follows:
| Seat sealing surface or lining materials | Code name | Seat sealing surface or lining materials | Code name |
| Copper alloys | T | Nitrided steel | D |
| Rubber | X | Carbide | Y |
| Nylon | N | Rubber-lined | J |
| Fluoroplastics | F | Lead-lined | Q |
| Babbitt alloy | B | Enamelled | C |
| Cr13 series stainless steel | H | Boron-nitrided steel | P |
| Monel alloy | M | Ceramic | G |
| Austenitic stainless steel | R | Plastic | S |
Note: The material code for the seat sealing surface machined directly from the valve body is denoted by ‘W’; where the materials of the seat and disc (gate) sealing surfaces differ, the code for the lower-hardness material is used (except for diaphragm valves).
The internationally recognised designations for sealing face materials in MSS SP 25-98 are shown in the table below:
| Sealing surface materials | Logo | Sealing surface materials | Logo |
| Aluminium | AK | Neoprene | CR |
| Brass | BRS | Butyl rubber | IIR |
| Bronze | BRZ | Ethylene-propylene rubber | EPR |
| Carbon bronze | CS | Fluorinated rubber | FPM |
| Cast iron | CI | Silicone rubber | SI |
| Ductile iron | DI | Stainless steel | SS |
| Malleable iron | MI | 13Cr | CR13 |
| Surface-hardened | HF | 46252 | 46252 |
| Integral seat | INT | 18-8Mo | 18-8Mo |
| Nitrided surface-hardened steel | SH | Nylon | MYL |
| Asbestos | ASB | Polytetrafluoroethylene | TFE |
| Nitrile rubber | NBR | Ethylene-propylene-diene monomer rubber | EPDM |
