Weakening of a knife steel

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flatlander88

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Jan 11, 2011
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I was just watching the video embedded in the Esee /Junglas vs Buck/Hood Hoodlum thread and I got to wondering. Does the steel on a knife weaken over time from being used? :confused: Hope this isn't too dumb.
For example, in the video the guy does some batoning and then he smashes a bone with the back of his knife. If a person were to do this on a regular basis, maybe practicing some skills would he/she have to worry about the knife if he/she later decides to head out for a few days in the backcountry?
Does a blade just break or fail all at once or can it be a process of weakening over time? I hope I described this well enough to get my point across.
Thanks
Flatlander
 
There's potentially a whole 'can-o-worms' being opened up in your question.

Personally, unless there's already some defect/flaw/corrosion/cracks/etc in the steel, I don't believe that decent knife steel gets weaker over time. Many believe just the opposite, that some steels at least, actually get better with age (that's the can-o-worms I mentioned). Pretty strong opinions on both sides of that issue.

There's also a concept called 'work hardening' of steel. I'm not an expert on this, but it basically implies a hardening/toughening of steel over time, resulting from physical forces acting upon the steel.

I do know, as do many other knife nuts like me, that there are an awful lot of very tough, very strong, and very beautiful OLD knives out there. The good ones will last almost forever, if they're used as a knife is intended, and properly taken care of.
 
if you mean that stress builds up in a knife from hard use--i do'nt think this happens. there is such a thing as metal fatigue but i believe that applies to springs & maybe things like levers that do a lot of back & forth flexing. we have several Phd metal xperts on the forum but they may not chime in. mete is one that comes to mind & knarfeng whom field is poly & COATING plastics has a lot of metal knowledge & may give you a definitive answer.--dennis
 
Obsessed with Edges said:
I do know, as do many other knife nuts like me, that there are an awful lot of very tough, very strong, and very beautiful OLD knives out there. The good ones will last almost forever, if they're used as a knife is intended, and properly taken care of.
Click to expand...

Truer words have never been spoken. I agree 100%.:thumbup:
 
The edge will suffer from weakening. Metal fatigue mentioned by Dennis is caused by deforming the edge. Doesn't matter if you realign the edge, or use it deformed, it still deforms over and over again, so eventually the pieces become weaker and break away. Although, that's not related to the age, just use.
 
Time itself will not weaken the knife unless you include corrosion in the discussion. However, doing those kinds of tasks you can accumulate damage that can add up and cause what seems like sudden failure. Chips in the edge, edge deformation, or unnoticed quench cracks that grow can all cause a knife to fail. It would seem like a sudden failure if you didn't notice the damage. Work hardening requires enough stress to deform the steel, and this will eventually lead to failure, like in a coat hanger. However, most knives are strong enough that this doesn't happen except at the edge, thus the edge deformation mentioned above.
 
If the steel undergoes plastic deformation, then there is an increase in dislocations in the atomic structure. This makes the steel harder, but also less ductile. If you keep moving the steel beyond its elastic range and permanently deforming it, it will lose all ductility and then fracture.

You can flex the steel without strain hardening, but don't bend it.
 
flatlander88 said:
I was just watching the video embedded in the Esee /Junglas vs Buck/Hood Hoodlum thread and I got to wondering. Does the steel on a knife weaken over time from being used? :confused: Hope this isn't too dumb.
For example, in the video the guy does some batoning and then he smashes a bone with the back of his knife. If a person were to do this on a regular basis, maybe practicing some skills would he/she have to worry about the knife if he/she later decides to head out for a few days in the backcountry?
Does a blade just break or fail all at once or can it be a process of weakening over time? I hope I described this well enough to get my point across.
Thanks
Flatlander
Click to expand...

The most accurate answer to your question: It depends.
 
Wow, thanks for the responses. I was just curious. I own many knives but only recently have I started to thinking more in depth about them. I've really only used my knives for skinning, butchering, and food prep but I have been making the transition to using them for more robust task. (not abuse but more than I have previously done) Makes me feel more confident when I am out.
Thanks again everyone
Flatlander88
 
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