Hardness vs Wear Resistance?

Ankerson said:
I haven't found one yet, but I am still looking, I am sure there is one out there someplace. :D

I likely wouldn't want to sharpen it though because I am sure it would be a real PITA.

I am talking about that very fine screaming edge here, not just shaving sharp etc....
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How about some of the ceramic blades? Any hope there?
 
Folderguy said:
How about some of the ceramic blades? Any hope there?
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Ceramic blades are excellent to slice tomatoes on a soft board. They come with a toothy edge which would last if they were not so brittle and are very tricky to sharpen.

No hope. Forget.

dantzk.
 
Folderguy said:
Hmmm. I was unable to find something like that on their website; perhaps I entered the wrong search terms. Do you recall what it's name was?
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Don't remember what it was, but they had one, it was a limited edition if I remember correctly.
 
There is an excellent article in the March issue of Blade Magazine, on just this subject. It has some startling conclusions. The article is called, "It's time for new knife tests"

EarlFH
 
Ankerson said:
Also taking the same steel, say something like S30V and 2 blades at say 60 HRC one blade can hold the edge a lot longer than the other if one of them has too much retained Austenite.
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Martensite is more important when manipulating the mechanical properties of steels. The purpose of quenching is to convert as much of the steel microstructure as possible from Austenite into Martensite.

A steel is heated first to a temperature above it's eutectoid temperature (usually above 700 degrees Celsius). This converts all the microstructure to Austenite (called austenitizing). Then the steel is rapidly cooled (quenched) so that it undergoes a martensitic transformation (converts the austenite into martensite).

The goal is to formulate as much martensite as possible in the steel because this microstructure is extremely hard and brittle (martensite is the hardest and most brittle microstructure). Unfortunately, these are not the only mechanical properties of steels that knife users desire.

What we (knife users) want is to increase ductility and toughness while maintaining the hardness. This is where tempering (heat treating) comes into play.

Tempering is achieved at temperatures below the eutectoid temperature so as to not to reverse the first step that I explained above and convert all the martensite to austenite. Tempering of martensite is usually done between 250 and 650 degrees celcius. This is where the skilled heat-treater is important.

If you do it right, the resulting steel will exhibit less hardness than the pure martensite but more ductility than martensite (which is what we want).

The difficulty is finding a balance between the two. You can not have hardness AND ductility.
 
Folderguy said:
What steels don't lose their screaming sharp edge after cutting the flaps off a box?
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I've heard claims that the ZDP-189 stay sharp even after cutting boxes?? I dunno. If I have to cut up a box and I can - I go get a "box cutter" and go to town. Why not waste $0.10 blade and save the edge on the good knife.
I don't pry staples out with a good knife either. I guess when you use your knife and when you won't is a topic all itself.
 
ans7812 said:
Martensite is more important when manipulating the mechanical properties of steels. The purpose of quenching is to convert as much of the steel microstructure as possible from Austenite into Martensite.

A steel is heated first to a temperature above it's eutectoid temperature (usually above 700 degrees Celsius). This converts all the microstructure to Austenite (called austenitizing). Then the steel is rapidly cooled (quenched) so that it undergoes a martensitic transformation (converts the austenite into martensite).

The goal is to formulate as much martensite as possible in the steel because this microstructure is extremely hard and brittle (martensite is the hardest and most brittle microstructure). Unfortunately, these are not the only mechanical properties of steels that knife users desire.

What we (knife users) want is to increase ductility and toughness while maintaining the hardness. This is where tempering (heat treating) comes into play.

Tempering is achieved at temperatures below the eutectoid temperature so as to not to reverse the first step that I explained above and convert all the martensite to austenite. Tempering of martensite is usually done between 250 and 650 degrees celcius. This is where the skilled heat-treater is important.

If you do it right, the resulting steel will exhibit less hardness than the pure martensite but more ductility than martensite (which is what we want).

The difficulty is finding a balance between the two. You can not have hardness AND ductility.
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I was trying to keep it simple.... Didn't want to go into a deep discussion on HT here. ;)
 
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This may not be for this thread - so let me know by not responding :)

I read in a few sharpening and other steel threads, that the steel behind the factory grind was better and that after a knife had been resharpened one or two times, it's properties, like the ones discussed earlier changed and became tougher, more resistant to wear and such. Anyone care to comment - or not?
 
cziv said:
This may not be for this thread - so let me know by not responding :)

I read in a few sharpening and other steel threads, that the steel behind the factory grind was better and that after a knife had been resharpened one or two times, it's properties, like the ones discussed earlier changed and became tougher, more resistant to wear and such. Anyone care to comment - or not?
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That's what I have found over the years to be true.
 
EarlFH said:
There is an excellent article in the March issue of Blade Magazine, on just this subject. It has some startling conclusions. The article is called, "It's time for new knife tests"

EarlFH
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I've been unable to find that article online. Perhaps you have a link to it. Or maybe you could fill us in on some of those startling conclusions. :thumbup:
 
Folderguy said:
I've been unable to find that article online. Perhaps you have a link to it. Or maybe you could fill us in on some of those startling conclusions. :thumbup:
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I would love to hear them too....
 
Ankerson said:
I would love to hear them too....
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I'm having a problem finding it on-line also. I've sent an email to the magazine to see if they can direct me to it.
It's a pretty involved, but interesting, article, on balancing the alloys, and heat treats for different uses. What works for cutting one kind of material, is very poor for others, and they all have to be tailored to the specific use of the knife.

EarlFH
 
Ankerson said:
I bolded the one thing you got right in that post....
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Well, cheap shots - what else left for you? Try to do some real testing may then you see what I am talking about. So far I only see you being the one who have "prove by test" excellence of new "supersteels" and whatever crowd of "steel experts" came up here.

This activity you have is driven not by search for truth but by search for proves for what everybody talking about - it is bit better then what other "experts" do - keyboard typing, but it is not tests. With such a flexible procedure and criteria you have no wonder that you find what you are already know - this is human nature.

But this is not testing. More like knife TV commercial.

It is really unfortunate that energy and will to do something - pretty unique here, wasted to this kind of thing, while you really may do some useful testing.

Thanks, Vassili.
 
nozh2002 said:
Well, cheap shots - what else left for you? Try to do some real testing may then you see what I am talking about. So far I only see you being the one who have "prove by test" excellence of new "supersteels" and whatever crowd of "steel experts" came up here.

This activity you have is driven not by search for truth but by search for proves for what everybody talking about - it is bit better then what other "experts" do - keyboard typing, but it is not tests. With such a flexible procedure and criteria you have no wonder that you find what you are already know - this is human nature.

But this is not testing. More like knife TV commercial.

It is really unfortunate that energy and will to do something - pretty unique here, wasted to this kind of thing, while you really may do some useful testing.

Thanks, Vassili.
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I refuse to get into a worthless pissing contest... ;)

I have my way of testing and recording information and it's very repeatable and proven to be consistent.

I have been testing knives and steels off and on since the 80's.

I have stated that my results are not the end all beat only results out there.

I am only interested in facts and finding the truth in the end. Only the facts and the truth are interesting to me. :)

I don't go around posting about others testing methods saying they are wrong either...... I have enough respect for others peoples efforts not to do that. ;)

That's something to think about.....
 
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