What is the name of this rust proofing?

Go to the hardware store. Buy some random piece of steel hardware, such as a padlock hasp or other such thing that might be exposed to weather. The steel item is likely treated with some electro-chemical process to protect it from rust. I’m not talking about galvanizing, and I’m not talking about a simple nickel or chrome plate job. I’m referring to that finish that is sort of goldish, sort of greenish, sort of pinkish in color. It also appears to be bonded to the metal, almost as if the surface of the steel has been altered, much as anodized aluminum is. So, this finish (or this finishing process), does it have a name? Either a company’s trade name or a generic term used to describe such a finish?

Anodizing tends to refer specifically to an aluminum substrate, and this peculiar multi-colored oxide finish is always on steel, not aluminum. I’d love to know what to call this stuff, rather than having to provide the rather long-winded explanation presented above. Any thoughts? (Let me guess - it really is called anodizing and I’m just wasting everyone’s time, right?)

I think it’s called (something like) zinc chromate. Rather than a plating or a dip, like galvanization, it’s a wash. It is not as effective as some other treatments, but it does ward off corrosion, and it’s cheap.

Chromate’s not very durable, and seems largely to keep the thing from rusting on the store shelf. It’s at least longer-lasting than bluing, which still hangs on as a way to keep a box of carpet tacks from turning into a rusty blob.

If you want long-lasting, you need to be in the realm of hot-dip zinc, which is that rough finish commonly found on stuff like gate hardware.

Interesting. Thanks…

The goldish-greenish finish is cad (cadmium) plating. Very effective at stopping corrosion, but falling out of favor because of the toxicity of cadmium.

Always put a cad washer between an SS bolt and an aluminum structure…