Learn about the key ASTM material specifications for valves. A cast valve body is manufactured by pouring liquid metals into molds and is common for valves above 2 inches in diameter. A forged valve body is produced by forging and machining solid steel. The key specifications for cast steel valves body materials are ASTM A216 (WCA, WCB, WCC), ASTM A352 LCB/LCC (low-temperature), and ASTM A351 CF8/CF8M. ASTM A105, A350 and A182 cover body materials for small size (or high pressure) forged valves.
First, let’s clarify the difference between cast vs. forged valve, even if it may seem obvious: cast valves feature a cast body, forged valves have a forged body. That’s it! The difference relates to the valve body material construction technique, i.e. steel forging or casting.
Let’s now review the key cast valve body materials.
ASTM A216 WCA, WCB, WCC (CARBON STEEL HIGH-TEMP.)
The ASTM A216 specification covers 3 grades of carbon steel (WCA, WCB, and WCC), which feature slight differences in terms of chemical and mechanical properties. These grades for cast valves bodies match carbon steel pipes in grades A53, A106, API 5L.
ASTM A216 steel castings shall be heat treated and can be manufactured in the annealed, or normalized, or normalized and tempered conditions. The surface of steel castings shall be free of adhering elements such as sand, cracks, hot tears, and other defects.
|ASTM A216 carbon steel valves (cast), material chart|
|ASTM A216 GRADE||C||Mn||P||S||Si||Cu||Ni||Cr||Mo||V|
|WCA UNS J02502||0.25(1)||0.70(1)||0.04||0.045||0.60||0.30||0.50||0.50||0.20||1.00|
|WCB UNS J03002||0.30(2)||1.00(2)||0.04||0.045||0.60||0.30||0.50||0.50||0.20||1.00|
|WCC UNS J02503||0.25(3)||1.20(3)||0.04||0.045||0.60||0.30||0.50||0.50||0.20||1.00|
- For each reduction of 0.01% below the specified maximum Carbon content, an increase of 0.04% manganese above the specified maximum is allowed up to a maximum of 1.10%.
- For each reduction of 0.01% below the specified maximum Carbon content, an increase of 0.04% Mn above the specified maximum is allowed up to a maximum of 1.28%.
- For each reduction of 0.01% below the specified maximum Carbon content, an increase of 0.04% manganese above the specified maximum is allowed to a maximum of 1.40%.
ASTM A352 LCB/LCC (CARBON STEEL LOW-TEMP.)
The ASTM A352 specification covers multiple grades of low-temperature carbon steel (called LCA, LCB, LCC, LC1, LC2, LC3, LC4, LC9, CA6NM) for cast steel valves, flanges, fittings, and other pressure-containing parts.
Chemical composition of A352 cast valves Gr. LCA/LCB/LCC (valve material chart):
|ASTM A352 LC3||0.15||0.6||0.65||3.5|
|ASTM A352 LCA||0.25||0.6||0.7||0.5||0.2||0.5||0.3||0.03|
|ASTM A352 LCB||0.3||0.6||1||0.5||0.2||0.5||0.3||0.03|
|ASTM A352 LCC||0.25||0.6||1.2||0.5||0.2||0.5||0.03|
ASTM A351 CF8/CF8M (STAINLESS STEEL)
The ASTM A351 specification covers austenitic steel castings for valves, flanges, fittings, and other pressure-containing parts.
The most common grades are ASTM A351 CF3, CF8 (SS304), and CF8M (SS316).
The steel shall be made by the electric furnace process with or without separate refining such as argon-oxygen decarburization.
Any ASTM A351 cast part shall receive heat treatment followed by a quench in water or rapid cooling. The steel shall conform to the chemical and mechanical requirements set by the specification.
ASTM A351 stainless steel valves, chemical composition