Alloy steel valve bodies, typically WC6, WC9, C5 and C12, are specified for elevated temperature and hydrogen service where plain carbon steel would lose strength or suffer attack. Refinery hydroprocessing, power station steam systems and high-temperature process units all use them.
Alloy bodies are expensive and their value depends heavily on traceability. A WC9 valve with a material certificate is a strong item; the same valve with the marking ground off is a question mark, because the alloy content cannot be assumed.
Review points
What decides the value of alloy steel valves
Grade marking
WC6, WC9, C5 and C12 are stamped on the body. Photograph the stamping clearly.
Certification
Material test reports are the difference between a confident purchase and a cautious one.
Service history
Hydrogen, steam or high-temperature process. The service tells us what the trim has seen.
Selling it
How to present the lot
Count by size and pattern, and note the marking on the body. If you have certificates, include them; if you do not, say so rather than implying they exist.
Do not separate trim from bodies to sell them individually unless the trim is clearly identifiable and valuable on its own. In most cases the assembly is worth more together.
Questions sellers ask
How do I tell WC6 from WCB?
The body stamping. WC6 contains chrome and molybdenum and is marked as such; WCB is plain carbon.
Do you buy alloy valves without certificates?
Yes, at a discount, because the material has to be verified before resale.
Are alloy valves worth much more?
Typically yes, sometimes several times the value of an equivalent WCB valve.