Steel colouring?

[Derek15555]

I've been wondering if there is any way to permanently colour steel when hardening or tempering? If not, are there any other methods to colour steel?

 

[Frank Niro]

It's never permanent if you mean does it go all the way through the steel. In fact it's a super thin coating. Frank

 

[Mahoney]

The colors from heating steel are just oxide layers on the surface, as are bluing and browning (chemically induced oxide layers), and as Frank pointed out, a little time with some abrasive will remove any of them. There's also "color case hardening" which can have very pretty results and is a little more abrasion resistant, but again the colors are just an oxide layer and it's a process not really applicable to blade steel, but could be interesting on bolsters, liners, etc. The most durable colors on blade steel are the various nitride coatings and the "diamond like coatings". They are thin, but some are really abrasion resistant, the DLC coatings in particular. Not exactly DIY processes though.

 

[Derek15555]

Great! Thanks very much for the information.

 

[Chris Lambeth]

A lot of steels temper too low to use a nitriding process on without losing your desired hardness. I color with bluing, parkerizing (I know, I know, but customers ask and I perform), duracoat, cerakote, acid etc. I found a way to color D-2 even with a black finish. Most of these methods are not difficult.

 

[Bill DeShivs]

The DLC process is under 300 degrees.

 

[Chris Lambeth]

Cool, very cool, compared to other forms. One of the nitriding processes I helped build for Siemens in their power generation (think hydro-electric dams and nuclear) operates at 1050f. But I'll never run out of kaowool now...