You see "WCB" cast into the body of a carbon steel valve. Here is what those three letters tell you, and why they matter when you choose a valve.
The standard and the grade
ASTM A216 is the standard for carbon steel castings intended for high-temperature service and suitable for fusion welding. It has three grades: WCA, WCB and WCC. WCB is by far the most common for valve bodies.
- Chemistry: carbon 0.30% max and manganese 1.00% max, with limits on residual elements.
- Strength: tensile strength 485 to 655 MPa (70 to 95 ksi), yield strength 250 MPa (36 ksi) minimum.
Where WCB valves are used
WCB is the standard choice for industrial lines where cast iron isn't strong or tough enough and stainless isn't needed: steam, oil, gas, hot water and general process service. Its working temperature range is commonly given as about −29 °C to 425 °C, subject to the valve's pressure-temperature rating.
It is carbon steel, so it will rust. It is not the right choice for corrosive fluids or for food and pharma service.
WCB compared
| Material | Typical marking | Best for |
|---|---|---|
| Grey / ductile cast iron | GG25, GGG40 | Water and low-pressure utility lines (PN16) |
| Cast carbon steel | WCB | Higher pressure and temperature: steam, oil, gas (Class 150 / 300) |
| Low-temperature carbon steel | LCB | Service below −29 °C |
| Cast stainless | CF8 (304), CF8M (316) | Corrosive, food, chemical and pharma service |
Reading the whole marking
On a WCB valve body you will usually find the brand, the size, the class (150 or 300), "WCB", and a flow arrow if the valve is directional. Ask for the certificate of quality and testing, and check that it names the same material and class.
What we stock
YONGLONG cast steel ball valves in ASTM A216 Gr. WCB, Class 150 and Class 300, with flanged raised-face ends to ANSI B16.5, supplied with a certificate of quality and testing.