316 stainless, cast as CF8M or forged as F316, is specified wherever chlorides, mild acids, food products or clean service rule out carbon steel. The molybdenum addition gives it pitting resistance that 304 lacks, which is why it is the default stainless valve material in chemical and pharmaceutical plants.
The value of a used 316 valve is driven by the body material more than by the trim, because the scrap and re-melt value of the alloy sets a floor under the price. That makes stainless lots much easier to buy than carbon steel lots, and it means even damaged stainless valves have a route to market.
Review points
What decides the value of 316 stainless steel valves
CF8M versus CF8
CF8M is the 316 cast grade and is worth more than CF8 (304). Check the body marking.
Surface condition
Pitting and crevice corrosion matter in sanitary and pharmaceutical service; less so in general utility.
Documentation
Material certificates carry weight, particularly for pharmaceutical and food service.
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 304 as well as 316?
Yes, though 304 is worth less. Mark the grade clearly on your list.
Are stainless valves bought by weight?
No. Usable stainless valves are priced as valves, and the alloy value is only a floor.
What about 316L?
316L is common in sanitary service and is purchased on the same basis as 316.