What went wrong with my quench

B

Bandics

Joined
Jan 2, 2009
Messages
3
Ok, let me start with some general Info.
I am a beginning maker with about 20 knives made.
The steel I am using is 02.
Cleaned the blade to near finished.
I got the knife up to temp. in my forge, and quenched it in oil that was room temp. I seconded guessed the temp. do to the reaction of the oil so I got the knife to temp agian ,checked it with a magnent, and quenched it for the 2nd time.

After the quench the blade now has many surface defects shaped like round spots, very textured like reptile scales. Looks cool actually, but not what I was after. Any ideas of what went wrong would be helpful.
Thak you all
R. Bandics
 
That's just decarburization. It is where some of the carbon has migrated out of the steel. You can help mitigate it by putting a skim coat of refractory cement or satanite on the blade before heat treating. Did it pass your file test? If so, you can grind away the decarb and finish the knife. Personally, I like the decarb look and I etch some of my blades to make it more obvious. Makes an awesome frontier/aged finish, but I'm a little wierd like that.

Oh, and welcome to BF.
 
If the spot are perfectly round, it's the oil creating bubbles and cooling the steel at a different rate. I had the same thing on my first few but once I started agitating the oil (swishing the pan back and forth) the bubbles went away.
 
I'd agree it's one of the two above things. If you're generating a lot of scale in heat treating, you're probably overheating though.

Just out of curiosity, where'd you find the O2? I'm always on the look out for it since it's kind of tough to find and I like what it does in damascus.

Thanks,

-d
 
Check your forge atmosphere and shoot for a reducing environment (flame coming out of the front) to reduce some of that decarb. And as was suggested, make sure to agitate the blade in the oil tip to butt or edge to spine (NOT side to side).

--nathan
 
That tool steel had been on my bench for some time, I may have been mistaken as for the Steel type. I Looked at the remaining bar, with yellow paint, and think it is 01(I would have never bought D2). I am using old motor oil and was unaware of any pre warming procedure. What Temp. should the oil be prewarmed? Many of the spots are perfect and the environment in my forge is inconsistant. Anyway its one mistake Im glad happened, it did produce some interesting texture.
Thank you all
R. Bandics
 
Ahhh, OK. I was hoping you had found a source for O2 (not D2). :)

Let us know how the knife turns out!

-d
 
You might want to start by reading the "good info here" stickies

there really is good info there, and all sorts of basic HT issues are addressed as these questions seem to repeat about every 2 months or less.

-Page
 
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