Invar, also known generically as FeNi36 (64FeNi in the US), is a nickel–iron alloy notable for its uniquely low coefficient of thermal expansion (CTE or α). The nameInvar comes from the word invariable, referring to its relative lack of expansion or contraction with temperature changes.
Polyoxymethylene, also known as acetal, polyacetal and polyformaldehyde, is an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability. Wikipedia
We can have most steel galvanized for $1 per pound and a 2-3 week wait. Some steel comes pre-galvanized and if not in stock, we can bring it in 1-2 days.
Galvanization (or galvanizing as it is most commonly called in that industry) is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which parts are submerged in a bath of molten zinc.
Galvanization - Wikipedia