What's the best soak time for Champalloy?

Phillip Patton

Phillip Patton

Knifemaker / Craftsman / Service Provider
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Jul 25, 2005
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I'm working on a large knife using this alloy, and I'd like to get it right. The only blades I've made using this stuff were test blades, and didn't cut very well. Someone here on the forums offered to test the Rockwell hardness for me, and they were only about 50 RC along the edge. After reading Kevin Cashen's posts in the thread about O1, I'm thinking maybe I didn't soak them long enough or at the right temp. Anybody know what's going on?
 
It depends upon the prior heat treatment as well. I always work with spheroidized steel in the heat treatment. I soak this stuff at 1500F for at least 4 to 5 minutes after the rebound of my salts (Crucible recommends around 10 minutes). This should yield at least a 62-63 HRC. Quenching is virtually never an issue with this stff, I have measured a 61 HRC off 1/2" stections that I just threw on the floor to cool.
If a shorter time at 1500F doesn't work, shoot for the higher end, from 1525F-1550F.
 
I was hoping you would see this, Kevin. Your the only maker I know of who uses this steel.
I also always spheroidize anneal my blades. I realized I neglected to record my soak temp, but I'm pretty sure it was 1475. I soaked one blade for about 9 minutes. The other one I triple quenched using a forge to austenitize. They were both consistently soft at the edge, although the triple quenched was about one point harder overall. The tangs of both pieces are around 60 RC. What do you think went wrong? Not hot enough?
Thanks.
 
1475F is too cool. Crucible recommends a minimum of 1500F on high heat.
When I first started using salts, I noticed the opposite effect, i.e. a tang ricasso area that was noticebly softer while the edge hardened fine. After going to incresing longer soak times at the same temp (1500F) I found the hardness going up in the tang and ricasso as well. Don't be afraid of a longer soak either, I have done some tests that took the soak beyond 10 minutes at 1500F on L6 with not noticeable difference- other than it got harder than heck;)
 
Ok, I'll try hotter next time. Do you think that was enough to result in the wierd hardness readings?
 
Phillip - when you used the forge to austenize, how did you determine the temperature? Color? Magnet? Did you soak
 
I heated it till non magnetic, let it get a little hotter, and probably soaked it for a minute or so. I was trying to determine if 3 "quick" soaks would produce a better or worse blade than the recommended heat treat.
 
I realize this stuff isn't 1095, but at what point does one have to worry about grain growth? Austenizing and soaking in a forge - without overheating - can be quite a balancing act...
 
Wulf said:
I realize this stuff isn't 1095, but at what point does one have to worry about grain growth? Austenizing and soaking in a forge - without overheating - can be quite a balancing act...
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That's why I asked about soak times. The two test blades I made both had pretty fine grain.
 
Kevin, I went back to a thread I started when I made the L-6 test blades and found that the austenitizing temp was not 1475, but 1510. Here's the quote in full:

"I forged them both from 1" round bar, and normalized them both 3 times.
Then I annealed them in my evenheat oven. After which they were actually soft enough to drill. Then I ground all the scale and hammer marks off, leaving the edge good and thick to account for decarb. For the single quench blade, I put it in the evenheat oven, which had been preheated to 1510 F and left it in for 12 minutes. It takes 3 or 4 minutes to come up to heat, so I figure it was soaking for 8 or 9 minutes. Then quenched in oil. The triple quench blade was brought up to heat in my forge and soaked only long enough to be heated evenly. After quenching in oil i gave it a snap temper then left it in the freezer for 24 hours. The repeated for a total of 3 cycles. Both blades were tempered twice at 375 for 2 hours, freezing between tempers. "
 
Well, now I'm curious. Why would the tang be the RHC60 hoped for and the edge be only RHC50? One would presume the edge would heat first and cool fastest. - both probably leading to it being harder than the tang.

2 suggestions (questions?)

  • Is decarburization possible
  • Is it possible that the blade edge flexed a bit or the Rockwell tester did not do well on the angle of the primary bevel?
Rob!
 
I don't think decarb is the problem, because I left the edge pretty thick.
The spine of the knife is tapered same as the edge, but it reads as harder also.
It's a mystery to me...
 
From everything you have told me I would tend to agree that I would doubt the rockwell reading. I have never got and accurate reading off an edge bevel. I take that back, I once did a test blade on which I left the edge incredibly thick and put the blade spine down on the anvil and took my readings straight down onto the edge. If it were not for the tang pat I may also suggest that you have a mislabled steel, because this just doesn't happen with L6.
 
Kevin R. Cashen said:
From everything you have told me I would tend to agree that I would doubt the rockwell reading. I have never got and accurate reading off an edge bevel. I take that back, I once did a test blade on which I left the edge incredibly thick and put the blade spine down on the anvil and took my readings straight down onto the edge. If it were not for the tang pat I may also suggest that you have a mislabled steel, because this just doesn't happen with L6.
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I tend to suspect the rockwell tester also. (I hope I don't offend the guy who was nice enough to do this for me for free. :) )
But that's the only thing that would seem to make sense.
What kind of performance edge retention-wise should I expect from this L6?
That might answer some questions also.
 
Phillip Patton said:
What kind of performance edge retention-wise should I expect from this L6?
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If you heat treat this L6 properly, you will NOT have any complaints about edgeholding or toughness, period. It's great stuff!:thumbup:
 
A bad RC reading wouldn't necessarily explain why the blades didn't cut well.
 
Danbo said:
If you heat treat this L6 properly, you will NOT have any complaints about edgeholding or toughness, period. It's great stuff!:thumbup:
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That's great, I'm sure you're right, but could you get more specific?
The single quench blade averaged 150 cuts on 1/2" rope, the triple quench 190. Is that good or bad??
 
Phillip Patton said:
That's great, I'm sure you're right, but could you get more specific?
The single quench blade averaged 150 cuts on 1/2" rope, the triple quench 190. Is that good or bad??
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Talk to Mr. Cashen about the testing. I just collect the knives; he does the testing. :)
 
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