Here’s a Weird One...

SW-EDC SW-EDC - it's your sig pic that consistently doesn't show. Honestly it's annoying because it takes up a good amount of vertical viewing space.

Crazy break there, it's like it delaminated and started peeling back - but knife steel isn't even laminated in that direction. Weird and I am sure KAI would like to see this knife. No way temp changes should affect steel unless we are getting a good deal more extreme.
 
I'm not an expert on the topic , but I believe part of the tempering process is to relieve internal stresses induced by knife making . Not done properly on this knife . The small thermal stress added by OP was just enough to release the internal stress already present . BANG ! :eek:
 
Icehawk said:
SW-EDC SW-EDC - it's your sig pic that consistently doesn't show. Honestly it's annoying because it takes up a good amount of vertical viewing space.

Crazy break there, it's like it delaminated and started peeling back - but knife steel isn't even laminated in that direction. Weird and I am sure KAI would like to see this knife. No way temp changes should affect steel unless we are getting a good deal more extreme.
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Ok, I'll try to fix that. I'm consistently on mobile so might have to go on to my laptop. Thanks.
 
Well look at this:

Wutt.jpg


I gave a solid stab into particle board and...this.


Ive done this before with no ill effects. Apparently temp change does affect 8cr.
 
W. Anderson said:
Well look at this:

Wutt.jpg


I gave a solid stab into particle board and...this.


Ive done this before with no ill effects. Apparently temp change does affect 8cr.
Click to expand...
Confidence once again destroyed . But maybe better to know than not . Be interested to know what Kershaw Kai has to say . Or even just somebody who actually understands metallurgy .
 
W. Anderson said:
I'm gonna make a 'tanto' out of it with the ole dremel. I have to class this as "uncertain steel" however,
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Hard to believe this is steel formula related . I've really beat on and even thrown knives with this steel type with no problem . Still think this has to be faulty heat treat or processing . ' course I never did the freeze to boil test on my knives .
 
DocJD said:
Hard to believe this is steel formula related . I've really beat on and even thrown knives with this steel type with no problem . Still think this has to be faulty heat treat or processing . ' course I never did the freeze to boil test on my knives .
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I agree, man, but this is what happened. I've killed the everloving crap out of my 4KX with no issuues, but this out of nowhere...
 
DocJD said:
Hard to believe this is steel formula related . I've really beat on and even thrown knives with this steel type with no problem . Still think this has to be faulty heat treat or processing . ' course I never did the freeze to boil test on my knives .
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I have thrown mine into oak as well, a few throws loosens the blade a bit, but an eighth turn eliminates all play.
 
W. Anderson said:
I have thrown mine into oak as well, a few throws loosens the blade a bit, but an eighth turn eliminates all play.
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Maybe some sort of metal fatigue , built up over time and coincidently shows itself now ? Hopefully more knowledgable members will weigh in on this phenomenon . Meanwhile , I'm keeping my knives in a temp controlled environment (sock down pants ) .
 
And this is why the internet needs a sarcasm font.

Boil/freeze should not be enough temp diff to do much to steel, which is why the OP is so interesting, as is the mode of failure (crack following the edge as it does) W.A's just beating a knife until it breaks. So are we surprised that stabbing into a hard material broke the tip of a knife, exactly like every other knife tip break? No, we are not. Nothing to do with heat-treat or steel specifically, just breaking a knife.
 
gadgetgeek said:
And this is why the internet needs a sarcasm font.

Boil/freeze should not be enough temp diff to do much to steel, which is why the OP is so interesting, as is the mode of failure (crack following the edge as it does) W.A's just beating a knife until it breaks. So are we surprised that stabbing into a hard material broke the tip of a knife, exactly like every other knife tip break? No, we are not. Nothing to do with heat-treat or steel specifically, just breaking a knife.
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Hopefully , you're right . I know that extreme cold can make metals brittle , but only while they are cold . Not a permanent change in structure .

I believe that the eye-roll emoji indicates sarcasm ?:rolleyes:
 
To weaken a product through rapid heat change you would need multiple cycles so makes a freeze, heat, hack, freeze, heat, hack, repeat until catastrophic failure. You probably could give the physical abuse side mostly it would help to make the weakness present quicker. It is also possible that a proper heat treat helps reduce the issue for metals as I have only seen this type issue with pots, pans, and cans all that probably never received any heat treatment.
 
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