D2 Question

[cotdt]

It's my understanding that Bob Dozier does something similar in his D2 heat treat process. This is just my understanding cobbled together from a few things he's said about heat treating D2 in general - YMMV.

Bob Dozier has said that he uses multiple heat cycles, and can get 61 rc w/o cryo. So it seems like it, and it also seems like he is using the high temper. Just speculation of course. I have one of his blades and it performs amazing, also quite tough for D2.

Is this something that could be applied to other stainless steels as well (154cm, 13c26, etc) or does it only work with D2 because it's semi-stainless?
Would it be worth trying on CPM-D2 or would do little since their particle metallurgy already results in a consistent, refined grain structure.

It works for stainless steels too but the temperatures are different. If the initial quench temperature is too high then you get grain growth instead of refinement.

CPM-D2 does not heat treat the same way as D2. If you use the same heat treat for CPM-D2 you end up with something 2 points harder than what you expect from the datasheets. I've never broken any CPM-D2 apart so I don't know how the grain is like.

 

[gixxer]

You had mentioned that you do multiple quench on "other steels" besides D2,does this include A2? temps?

 

[cotdt]

You had mentioned that you do multiple quench on "other steels" besides D2,does this include A2? temps?

I'm still experimenting with A2, as I have a lot of this steel to break. I will try quenching first at 1700F (soak 30 min) and final quench at 1780F (soak 20 min). A2 has very fine carbides unlike D2 so I'm not expecting any obstacles. I've seen micrographs of A2 and its carbides look finer than even CPM steels.

 

[J.D.]

galadduin, thank you for the link, and the help. After reading all of this again, I think I get it, sometimes it takes awhile to soak in. If I understand all of this, what fixed your problem, could improve any D2 blade, because you get a finer grain, therefore a tougher blade. Is this correct? And when you air cool at 1900, 1800, 1700, approximetly how cool do you go between each heat cycle? Just trying to get the little details before trying it. I will get some D2 and give this a try. Test on some small pieces to break before and after tempering, should be fun.
Thanks again to all who commented and helped. Dale

 

[galadduin]

Dale,
I let the kiln drop to that temp before I put the blade in. During that time blade cools to room temp... And yes, it improves the mechanical properties of steel, you cannot be sure in what state the steel stock comes to you from the factory...
Emre