Heat Treating D-2 and CPM-154

TK Steingass

TK Steingass

Troglodyte Knifemaker
Knifemaker / Craftsman / Service Provider
Joined
Oct 16, 2010
Messages
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Fellow Knifemakers:

I just put up my new Sugar Creek KK-2 manually controlled HT oven. This baby will pay for itself in no time and drastically reduce my turnaround time with the HT companies. Maybe some of you can steer me to a controller that's significantly less than the $250 plus shipping upgrade that Sugar Creek wants?

For the CPM-154 I plan on a forced air quench between aluminum plates. A few questions for you more experienced in-house heat treaters:

1) Single or double wrap with stainless foil - what's the best way?

2) Can I use this expensive-ass foil more than once?

3) Single or double temper - why double?

4) Recommended way to cool between the double temper - forced air, still air, oven cool, oil?

I'm looking forward to hearing your experience.

Best regards,

TK
 
Some thoughts:

TK Steingass said:
Fellow Knifemakers:

I just put up my new Sugar Creek KK-2 manually controlled HT oven. This baby will pay for itself in no time and drastically reduce my turnaround time with the HT companies. Maybe some of you can steer me to a controller that's significantly less than the $250 plus shipping upgrade that Sugar Creek wants?

For the CPM-154 I plan on a forced air quench between aluminum plates. A few questions for you more experienced in-house heat treaters:

You can get satisfactory results without the forced air. I've seen someone actually create a tube with multiple holes in it to evenly distribute the forced air between the plates. That's probably overkill but a neat idea anyway....

1) Single or double wrap with stainless foil - what's the best way?

I do a single wrap with no troubles. Make sure the knife and foil are clean. I use alcohol to clean everything prior to heat treating. I place the knife in a folded piece of foil, and bend over/crimp the three open edges twice on each edge. Try and get all of the air out of the pack to reduce oxidation coloring. You don't really need anything like paper or oil in the packet, though some use it. I find it just creates more discoloration that has to be cleaned vs. the tiny bit of oxygen that is left in there anyway. As it burns, it can also baloon your packet. Use a flat piece of something (I use micarta) and a hammer to flatten out the crimps and get a good seal. Make sure the crimps do not overlap the blade in any area. I had one overlap a tip once and when I placed it in the plates, the extra thickness of the crimp bent the tip up during the quench. After all color is gone from the knife, you can cut open and check for straightness while still hot, then re-plate.

2) Can I use this expensive-ass foil more than once?

Maybe. It depends on its condition once you've cut the knife out of the packet. Sometimes the packet lightly "welds" itself to the blade in a few small places and can create tears. You want the packet to be air tight to reduce decarb. I just use a packet once and then toss it.

3) Single or double temper - why double?

Double temper is needed. The first temper and cool not only tempers your martensite, but it creates new martensite from retained austenite. This new martensite must then be tempered with a second temper.

4) Recommended way to cool between the double temper - forced air, still air, oven cool, oil?

Cool by taking out of the oven and letting it cool in still air. Once fully to room temperature, go back in the oven.

I'm looking forward to hearing your experience.

Best regards,

TK
Click to expand...

Hope that helps!
 
Last edited:
1. Single wrap with double edge folds works well for me.

2. No, the foil degrades during HT and then you cut the envelope open to remove your quenched blade, really not anything useable after that.

3. Double; the first tempers new Martinsite, the second tempers converted Martinsite from first temper (at least my understanding).

4. Let the blades cool unassisted then second temper.

Nathan beat me; shucks.

David Sharp
Sharpwerks
 
This is really fascinating stuff from those who know,just another reason to love bladeforums.:)
 
1. Single. I double or triple fold the edges.
2. No. (Although some people claim to do so with success.) The foil is cheap enough not to bother using it twice.
3. Double.
4. Still air.
 
The only thing I'll add is that I use a rubber hammer to hammer my creases flat. I find it helps me get a better seal.
 
To all:

Thanks fellas - you helped me out a lot.

TK
 
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