[luvdunhill]

ok, I accidentally ordered the wrong part from fastener-express... the alloy steel is black, and here I've been ordering the black oxide this whole time. Seems that alloy steel is a bit nicer, heavier, and doesn't mar as easily. What's your opinion?

 

[heatmizer]

Its black from case hardening and oil bath

 

[Troyhoot]

not sure about that specific material. But what we order and receive at work is covered in bluing which is blue black. It's there so it wont rust. Bare steel can and will rust within hours if not sooner. We get in sheets and tubing so we are talking very raw material though.

 

[ericj]

Depends on the alloy.

And as others have said, on coatings.