K390 Heat treat

S

Scaniaman

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Jun 15, 2012
Messages
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Hi,

I ordered some k390 to put in my next batch together with Magnacut, the k390 is going into some EDCs. I figure I'll use the same austenizing temp and soak time (2050F/1120C and appr 25 min) for the two steels. After LN2 I'll temper the Magnacut at 350F/175C 2x2 hrs.
Would that tempering temperature be too low for k390? Is 400F/205C more advisable? Where would the two options land me in Hrc?
Thanks!
 
My book has an austenitize vs hardness curve for K390. I don’t think it’s on my website anywhere. It was for 300F temper I think but 400F is safer for toughness and would be approximately 2 Rc lower than 300F. Someone with my book could check if my memory is bad.
 
Larrin said:
My book has an austenitize vs hardness curve for K390. I don’t think it’s on my website anywhere. It was for 300F temper I think but 400F is safer for toughness and would be approximately 2 Rc lower than 300F. Someone with my book could check if my memory is bad.
Click to expand...

Thanks! According to Amazon, I now can check for myself on June 23rd. It was about time I ordered that book.

Anybody heat treating K390 here, that can share their experiences?
 
I have Larrin's book and a little bit of experience. From the book:

1800-2050F 20 minutes plate quench cryo 400 temper

The chart only shows a 300F temper curve, but for that tempering temperature, this is what the chart says for a given hardening temp:
1800/63
1850/64
1900 and 1950/almost 65
2000/65.5
2050/66.6
2150/68

Just remember those hardness numbers are with a 300f temper.
I used 2050F, 20 minutes, plate quench, cryo, and 375F tempers. (64-65HRC) A client absolutely loves the knife. I forget what game animal he was using it on, pronghorn maybe, he absolutely loves the knife and the steel, mentioning that with the wear resistance K390 has, it was tougher than expected. Excellent steel.
 
Stuart Davenport Knives said:
I have Larrin's book and a little bit of experience. From the book:

1800-2050F 20 minutes plate quench cryo 400 temper

The chart only shows a 300F temper curve, but for that tempering temperature, this is what the chart says for a given hardening temp:
1800/63
1850/64
1900 and 1950/almost 65
2000/65.5
2050/66.6
2150/68

Just remember those hardness numbers are with a 300f temper.
I used 2050F, 20 minutes, plate quench, cryo, and 375F tempers. (64-65HRC) A client absolutely loves the knife. I forget what game animal he was using it on, pronghorn maybe, he absolutely loves the knife and the steel, mentioning that with the wear resistance K390 has, it was tougher than expected. Excellent steel.
Click to expand...

Thank you that is very helpful, I really appreciate it! So I will just follow the exact same HT that I am planning for Magnacut. Processing game is an excellent test for toughness.
 
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