1095 vs Stainless Steel

Buck_110 said:
Here is ingot steel NOT failing or micro-chipping:

http://www.scrapyardknives.com/ubbthreads/showflat.php?Cat=0&Number=202608&page=38&fpart=1&vc=1

http://www.scrapyardknives.com/ubbthreads/showflat.php?Cat=0&Number=451415&page=0&fpart=1&vc=1&nt=3

Any examples of powder steel undergoing the same, with similar results?
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Tempering has much more to do with it than just hardness, take 2 blades, same steel, but tempered differently, they will react differently.

Hardness can effect the steel, but that's not all of it.

There isn't just one fit all answer when talking about steels.
 
Ankerson said:
Tempering has much more to do with it than just hardness, take 2 blades, same steel, but tempered differently, they will react differently.

Hardness can effect the steel, but that's not all of it.

There isn't just one fit all answer when talking about steels.
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No doubt about it. Variables can fill volumes. It's science combined with experience.
 
Eight Trigrams said:
Dude, seriously... Assuming the new edge bevel is straight and not convex, you look at the height of it. You then look at the same model of knife that you own and measure the thickness of the blade at that height. Do a little math and that would tell you roughly what the angle is just by looking at it from the side. It's called "basic trigonometry".
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Well, what leads you to this assumption? Now assume that it is curved and if you look at reflection you may pretty much see that it is not straight. You actually may see that at the very edge it bends in quite radically and so here we have pretty different case.

So again here we have simple try to find excuse for difference between real life experience and "test show", this is actually part of the show naturally.

Thanks, Vassili.
 
For the ones brave enough to test claims of Superman-like toughness, when the knives fail well below published figures, they are blasted for their efforts.
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is this referring to something in particular? and testing knives is not testing steel, stress risers, bad grinds, poor heat treat, different profiles, there's too much variability to make a claim about a steel based on the test of an individual knife. That's why tests like charpy and izod exist.

Buck_110 said:
It is in fact true.

Can you provide a link, or elaborate on that "most basic heat treatment information" which shows this not to be the case?
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Depends on the alloys. Increasing tempering temp can cause secondary hardening in some, with a better hardness/toughness balance. This means there is not a simple inverse relationship between hardness and toughness. There is also tempering embrittlement to consider. You reduce the toughness of a steel as you increase tempering temp (decrease hardness) until you pass the embrittlement zone. And there's just the difference between alloys. Taking 1095 up to 64 causes a considerable drop in toughness, while many HSS are designed for that to be their working range and have higher impact numbers. Ingot D2 is one third as tough as CPM-3V with both around 60 Rc.
 
nozh2002 said:
So again here we have simple try to find excuse for difference between real life experience and "test show", this is actually part of the show naturally.
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you ignore everyone's personal experiences with real life use and rank steels based on your own "test show", so I don't know what you're criticizing.
 
nozh2002 said:
Well, what leads you to this assumption? Now assume that it is curved and if you look at reflection you may pretty much see that it is not straight. You actually may see that at the very edge it bends in quite radically and so here we have pretty different case.

So again here we have simple try to find excuse for difference between real life experience and "test show", this is actually part of the show naturally.

Thanks, Vassili.
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What "leads me to this assumption" is that it was already said that he sharpened it with an EdgePro, which is a jigged, flat-stone system. Those systems create flat bevels. Obviously the illusion of a curve to the bevel was your eyes playing "test show" on you.
 
Buck_110 said:
Can you post links to videos of them being laterally torqued and returning to true?
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I looked and no, I can't. I guess that means that only 154CM is capable of being manhandled in a vice, all real-world user's experience with 3V to the contrary. After all, if it isn't on a Busse-family company website, it didn't happen.

Anyways, I've realized that I haven't actually responded to the original post. From my use, I'd agree with knarfeng in his assessment. 1095 is roughly equivalent to AUS-8 in terms of edge holding at around the same RC. In all actuality, most stainless steels will hold an edge longer than 1095, sometimes considerably more.

So why do so many people prefer carbon steels over stainless steels? Carbon is much easier to sharpen back up. This, I believe, has to do with the mechanism of how both types of steels become dull.

Carbon steels tend to get dull because of edge deformation. If you use a carbon steel blade after its lost its razor sharpness until it's just clinging to its working edge and look at it under a loupe, the edge will look wavy and rolled from side to side. For the most part though, the steel hasn't gone anywhere, it's just moved. Mostly what's required to get back to razor sharp in that case is just realignment, which could be a butcher's steel or a strop, then bam, off to work again. Occasionally you give it a few passes on a stone just to freshen the edge up, but not very often. I actually believe most people here oversharpen their carbon steel, personally. Anyways... very easy edge to maintain.

Stainless steels, on the other hand, tend to get dull due to edge loss. You'll be able to work with them longer before you get to the point described above, but when you look at the stainless' edge under the loupe it'll look a lot more chipped and divoted. This is due to metal actually leaving the edge, as opposed to just getting pushed to the side. So while stropping still aligns what's left and can still produce a working edge, to get it back to initial sharpness actually requires grinding a new edge on there a lot more frequently. THIS is why people prefer carbon steel in the field. You don't have to fuss with the stones nearly as often.

But yeah, as far as pure, unadulterated edge retention goes, stainless all the way.

As far as toughness goes, I'm not sure there are any actually stainless steels that compare to well heat-treated 1095, just because of all the enbrittling chromium in the mix. I don't make a habit of breaking my knives, so I can't say from experience. All I know is that there are some stainlesses out there that can take all the punishment I can reasonably give, and that's good enough for me. (I'm looking at you, 12c27)
 
hardheart said:
you ignore everyone's personal experiences with real life use and rank steels based on your own "test show", so I don't know what you're criticizing.
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Well, ok - you do not know, thanks for sharing this.
Did you done any testing yet to talk about steels?

Thanks, Vassili.
 
Eight Trigrams said:
What "leads me to this assumption" is that it was already said that he sharpened it with an EdgePro, which is a jigged, flat-stone system. Those systems create flat bevels. Obviously the illusion of a curve to the bevel was your eyes playing "test show" on you.
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You are missing critical part which is it was touched up with Sharpmaker.
But aagain it is clearly visible on the picture - just pay attention.

Thanks, Vassili.
 
hardheart said:
is this referring to something in particular?
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No, it's a general statement. Don't get me wrong, there's a difference between testing a knife which leads to its destruction, and destroying a knife for the sake of doing so. In reality, anything can be destroyed.

hardheart said:
and testing knives is not testing steel, stress risers, bad grinds, poor heat treat, different profiles, there's too much variability to make a claim about a steel based on the test of an individual knife. That's why tests like charpy and izod exist.
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I agree. That's why I state "powder steel knives". Yet, most quote steel figures and apply them to individual knives. This is what misleads them about the toughness of knives themselves. To apply foundry numbers to knives is ridiculous. Some manufacturers, depending on what magic they are(or not) able to impart, can exceed, be on par with, or fall short of stated numbers. Numbers generated from individual knives are the only ones which account for valid data.

hardheart said:
Depends on the alloys. Increasing tempering temp can cause secondary hardening in some, with a better hardness/toughness balance. This means there is not a simple inverse relationship between hardness and toughness.
There is also tempering embrittlement to consider. You reduce the toughness of a steel as you increase tempering temp (decrease hardness) until you pass the embrittlement zone. And there's just the difference between alloys.
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I agree. The manufacturers willing to experiment will also discover favorable unknowns, too. In science, anything can change at any time.

Although there's not a simple relationship between hardness and toughness, a general, loose relationship exists. If steel is too soft, it can tear. If it's too hard, it can be brittle.
 
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nozh2002 said:
Well, ok - you do not know, thanks for sharing this.
Did you done any testing yet to talk about steels?

Thanks, Vassili.
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What do I not know? I know that when I want to check the edge angle on my knives, I use my laser goniometer. Before that, I measured with calipers and did the calculations. I have several printed books and gigs of reference materials on steel composition, alloy effects on properties, heat treatment, test papers from several sources that were published for peer review covering cutting of processed food, meat, vegetable matter, lumber, edge life, effects on cutting forces caused by level of edge polish, edge angle, slicing speed, and push cutting force. I have done informal cutting tests of cardboard, pine, and manila rope. I've looked at my own edges at magnification from 10x to 400x.

Do I have any formal testing? No, but the blanks have been cut and will go out for heat treat. That is all I'm going to say about it until the testing has been performed. Expect a rather lengthy post/blog entry when it is finished.

With plenty of pictures!
 
if i'm ever attacked by 425 pieces of string, i'm quite certain all of nohz's tests will come screaming to my forebrain and i will no doubt owe him a debt of gratitude for all the real world testing he provides us peasants.
 
hardheart said:
What do I not know? I know that when I want to check the edge angle on my knives, I use my laser goniometer. Before that, I measured with calipers and did the calculations. I have several printed books and gigs of reference materials on steel composition, alloy effects on properties, heat treatment, test papers from several sources that were published for peer review covering cutting of processed food, meat, vegetable matter, lumber, edge life, effects on cutting forces caused by level of edge polish, edge angle, slicing speed, and push cutting force. I have done informal cutting tests of cardboard, pine, and manila rope. I've looked at my own edges at magnification from 10x to 400x.

Do I have any formal testing? No, but the blanks have been cut and will go out for heat treat. That is all I'm going to say about it until the testing has been performed. Expect a rather lengthy post/blog entry when it is finished.

With plenty of pictures!
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I really like to hear this. Looking forward to see your test results.

Thanks, Vassili.
 
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