Hi
Spike42,
Black is the only routine color:
hot black oxide process – MIL-DTL-13924D [Note: the Class 1 solution used for mild steel is unsatisfactory for SS, Class 4 will work on 3xx SS]
electroplated black chrome – MIL-C-14538D
electroplated black nickel – no MIL spec, can be very glossy over bright nickel plating.
MIL specs are available at ASSIST:
The room temperature blackening solutions that I have tried didn’t work on SS (wiped off), but possibly improved products are available. See
Blackening
thread798-86272
Interference colors (which vary with thickness & viewing angle) can be produced by anodizing SS. There are maybe 2 companies in the US which do this; check the
site.
Oxidation by heating to various temperature in air (“heat treat tint”) will produce shades of yellow, blue and purple. This is a combination of interference coloring and doping. The contact points will not color as well, so you cannot do a basket of flat parts like washers, and other parts require some in-process motion. Ask your local heat treater & do some experimentation. Note that thicker coatings become porous and flaky. See
Heat tint of stainless steels
thread725-25564
Of course, you can electrodeposit copper, which allows a variety of finishes: blue-green, copper, brass, antique brown, etc.
TiN deposited via PVD gives the gold color commonly used on twist drills. Gold, rose gold, rose copper, brass, brown, bronze, black or charcoal grey also available; see