Monel, a nickel-copper alloy, resists seawater, hydrofluoric acid and a range of reducing environments that destroy stainless steel. It appears in marine, offshore, acid alkylation and specialty chemical service, usually as a body or as trim and internals in a steel body.
Because the alloy is expensive and often on allocation, Monel components retain value even when the valve is worn. A Monel trim set removed from a steel body is a legitimate purchase on its own.
Review points
What decides the value of monel valves
Body or trim
A steel body with Monel trim is common. Identify which parts are Monel.
Verification
Alloy verification matters here. Markings and certificates are the basis of value.
Service
Seawater, HF acid and specialty chemical service are the usual origins.
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
Do you buy Monel trim without the body?
Yes, when the parts are identifiable and the quantity justifies it.
How is Monel identified?
Body markings, certificates or a positive material identification test. We do not guess.
Is Monel still in demand?
Yes, because the alloy is expensive and lead times are long.