The medium or substance flowing through a valve will often determine the type of valve body material. Some valve body materials are best suited for high temperature applications while others are best suited for their corrosion resistance to fluid substance still others are selected based on a low cost factor. Most times, manufacturers of valves will aid you in selecting the right valve for a given application after supplying the needed information.
Material
|
Application Notes
|
| Bronze | Used for plumbing, heating and air-conditioning systems. Selected when line size is less than 3 inches |
| Cast Iron | Majority of iron valves are made of cast iron. Used in many applications. Cast Iron has a temperature limit of 450 degree Fahrenheit |
| Ductile Iron | Also called nodular Iron. It has good corrosion resistance. Most often used in the Marine industry and for underground pipelines. Ductile iron valves can be used in applications that experience vibration and shock. Ductile iron has a temperature limit of 650 degree Fahrenheit. |
| Steel | Steel valves can either be forged steel or cast steel. Forged steel valves are used when higher pressures and temperatures are required and the line size less than 2.5 inches. Cast Steel valves are used on line sizes over 2 inches when higher pressures and temperatures demand the use of carbon or alloy steel |
| Stainless Steel | Stainless steel valves are used when any form of problem is expected with corrosion in carbon steels or when high grade surface finishes are needed for reducing or eliminating contamination problems. Stainless steel valves are widely used in chemical process, petrochemical, pulp and paper, and electric utilities industries. |
| Thermoplastic | The chemical industry and many other industries make wide use of thermoplastic-bodied valves.The two common types of thermoplastic are in use namely: CPVC(Chlorinated polyvinyl chloride) and PVC(polyvinyl chloride). PVC is the most popular and can be used for more applications than other plastics. It can only be used up to 140 degree Fahrenheit. CPVC is used in many high temperature applications. CPVC valves can service temperatures of 45 to 75 degree Fahrenheit higher than PVC valves There is also TFE(Tetrafluoroetheylene) TFE is commonly used as seal material in quarter turn valves such as the ball or plug valve. |
Standard Control Valve Body Materials:
Valve body materials for most control valves fall under the basic standard types below:
Cast Material
|
Standard
|
Application Notes
|
| Carbon Steel | ASTM A216 Gr. WCB | For moderate services such as non-corrosive fluids. Higher pressures and temperatures than cast iron. If desired for extended high temperatures check the relevant code for suitability |
| Chrome-Moly Steel | ASTM A217 Gr. C5 | Used for mildly corrosive fluids such as sea water, oils. Resistant to erosion and creep at high temperatures. Can be used to 595 degree Celsius(1,100 degree F) |
| Type 304 Stainless Steel | ASTM A351 Gr. CFB |
Used for oxidizing or very corrosive fluids. Can be used above 540 degree C(1,000 degree F)
|
| Type 316 Stainless Steel | ASTM A351 Gr. CF8M | Used for oxidizing or very corrosive fluids, resistant to corrosion pitting and creep. Provides greater strength than 304 SS |
| Monel | ASTM A494 Gr. M35-1 | Resistant to non-oxidizing acids. Used with seawater and other mildly corrosive fluids at high temperatures. Expensive in terms of cost. |
| Hastelloy -C | ASTM A494 Gr. CW2N | Expensive |
| Iron | ASTM A126 Class B | Inexpensive and non-ductile. Used for water and non- corrosive liquids. |
| Bronze | ASTM B61 & B62 | ASTM B 61 typically used for valve trim. ASTM B 62 typically used for valve body. Can be used for water and dilute acid service. |
