Heat treat advice needed....I screwed up badly

G

godogs57

Joined
Apr 16, 2004
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I am an idiot....never done this before in twenty-something years. Heat treating my CPM 154 and on my tempering phase I left it in too long. I temper in a toaster oven with a thermometer like many here do. I temper for 2 hours at 375 degrees three times.

I forgot about it in my shop last night and left the dern blades in there all stinkin' night. It was my first of three tempering cycles.

Are my blades trashed? Can I re-heat treat to bring the hardness back up and then temper again?

I felt like I was in US Army Ranger school way back a long time ago and when you screwed up, they would ask you "Boy? Did you eat ten pounds of 'dumbass' for breakfast?" Apparently I did yesterday morning...

Any thoughts or opinions would be appreciated. Thanks in advance.
 
godogs57 said:
Are my blades trashed?
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No. If 375 was what you wanted, extra time at temp shouldn't hurt anything. This is just based on reading, I'm not a heat-treater myself. Folks who know for sure will chime in.
 
You have no problem. Just do the second temper as normal and you will be fine. Time is not nearly the enemy that temperature is. If a two hour temper goes for 10 hours there is little difference. If a 375F temper goes up to 400F, there is a big difference.
 
It may have hit 400.....it was hovering at 400 this morning. The dial on the temp control was adjusted to give me 375 at "winter" temps in my outside shop....we have a warm spell and it was right at 400 this morning.
 
Still not likely a problem. 375 is actually a little low for CPM154. 400 is the lowest the spec sheet shows. As mentioned, time is not the problem. Your knife should be fine.

Rob!
 
Whew! Breathing a little easier at the office this morning...thanks for y'all's input.

Next time around (when I have my head screwed on straight) should I try a higher temper? I hit 1950 degrees for 30 minutes, which gives me between 62 and 63 Rc. After the triple temper I am usually between 60 and 61...seems like that is where I should be with CPM 154, but I am always open to suggestions.

Thanks again everyone.
 
If you're worried that you went over temp or that the time was actually detrimental, then just high-heat temper them.
 
godogs57 said:
After the triple temper I am usually between 60 and 61...
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If that's what you like, keep it that way. Is it chippy or super hard to sharpen? I have my CPM-154 done to 58-59 and edge retention is excellent, not terribly difficult to sharpen, no chips when I test by chopping through a 2x4.
 
CPM 154 is supposed to finish up around 61 idealy from everything I have ever read.....never seen anything to contradict that.
 
Got home from work today and everything turned out fine. Hardness tester said 61. I let em soak for a second time for two hours. Life is good.

Thanks everyone!
 
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