Are powder steels superior?

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Folderguy

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Are powder steels superior?

If a powder steel is pounded on afterwards, during a forging process, does that change it?

Are powder steel blades as strong as similar non-powder steels?

And lastly, what are some of the better powder steels, and some of those that are more modest?

Thanks,

Folderguy
 
Folderguy said:
Are powder steels superior?
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Apparently :eek::eek:

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Fallkniven's 3G SGPS is nice. It has bettter edge retention that there VG10 but it is a little more brittle and harder to sharpen. All depends what you are going to be using the knife for.
 
SGPS is a real super steel and illustrates what can be done with powder metal blades. That steel can achieve high hardness yet still be tough !!
Finer carbides are always better and forging or rolling doesn't change the carbides .
You can make your own comparisons , for example 154CM vs CPM154 .They have the same composition but one is a powder steel .The CPM version is easier to sharpen yet holds and edge better [contrary to what you might think.] Better properties especially transverse toughness.It certainly takes a better edge ,my all round favorite.
Other powder steels I have are Fallkniven SGPS and S30V both very good performers.
 
1. Yes, for the desirable properties of hardenable steel, the PM process improves them
2. Not detrimentally if done correctly. The steel is subjected to heat and pressure after it is made when it is rolled. But the whole point of heating and moving steel is to change it.
3. Stronger and tougher. Many powder steels could not exist if made in a conventional melt.
4. Depends on what you are looking for. In knives I've used, the core of SGPS/SG2 has given pretty low edge retention relative to other alloys, close to AUS8. Vassili, bluntruth (sp), and Ankerson found similar, IIRC. For the alloy content and advertised hardness (62), that isn't impressive. S60V is very wear resistant, but had to be hardened a few points lower than S30V or S90V due to brittle failures. 9V does not reach even that hardness, which is probably one reason you don't see it in knives.

Otherwise (other CPM grades, Bohler-Uddeholm, Carpenter, Hitachi, Erasteel, etc) seem to be on the ball. PM processing was created to service the entire tool steel industry, which is orders of magnitude larger and more economically critical.
 
Yes they are.
I still however, like the "other" types of steel because they are easier to get super sharp edge. (VG10, 154CM, AUS8, 01, 1095).
 
mete said:
SGPS is a real super steel and illustrates what can be done with powder metal blades. That steel can achieve high hardness yet still be tough !!
Finer carbides are always better and forging or rolling doesn't change the carbides .
You can make your own comparisons , for example 154CM vs CPM154 .They have the same composition but one is a powder steel .The CPM version is easier to sharpen yet holds and edge better [contrary to what you might think.] Better properties especially transverse toughness.It certainly takes a better edge ,my all round favorite.
Other powder steels I have are Fallkniven SGPS and S30V both very good performers.
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Tougher as in less prone to snapping if subjected to prying/bending?
 
hardheart said:
http://materials-welding.blogspot.com/2007/09/toughness-ability-of-metal-to-deform.html

this should help, toughness as we generally refer to it is based on impact testing.
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Wow... too much for me!! LOL Thank you... :thumbup: I had no idea what I was getting into!

Now, back to laymen's terms: is a folder blade made of S30V steel, say in a Benchmade Kulgera, or in a Zero Tolerance 0300 or 0400, "tougher" than a 440C blade used in another folder??

What kind of meaningful comparisons are possible?
 
Folderguy said:
So, for instance, surviving a drop from a second story window onto concrete, landing on the tip? That sort of thing?
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Think less of knife scenarios and more of tool steels and other industrial applications when you think about steel toughness.

Dropping a knife on its tip is an impact failure. With toughness think more of the steels ability to absorb energy and deform without breaking. I always used to think of it this way; imagine trying to break a green branch off of a tree, the wood bends and bends and bends without actually breaking. That is toughness. It is able to deflect more without breaking. Prying with a knife is very similar.

I'm still a student though, just beginning to dabble in steels. Someone please correct me if I am wrong.
 
in general powder steels are tougher m4 & 3v are examples of alloys that impact well on charpy index. a sort of side impact pressure to measure deflection w/o chipping. really mete is a metallurgist & can answer the science much better than myself.however some guys like fowler,burke, siegle & sniper blades can do miracles with common carbon steels. as a general rule the powdered alloys have advantages such as extreme high heat working abilities.--dennis
 
Folderguy said:
is a folder blade made of S30V steel... "tougher" than a 440C blade used in another folder??
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according to Crucible's published numbers, yes. This is going to depend ulitmately on the heat treat of the specific knives, but S30V will exhibit higher toughness than 440C at 'optimum' hardness.

THG said:
Really, SG2 was that bad?
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I didn't do specific testing, just casual use. I found the edge would lose hair shaving sharpness by going blunt (not becoming rough/microchipping) pretty quickly.

http://www.bladeforums.com/forums/showpost.php?p=7445670&postcount=26
http://www.bladeforums.com/forums/showpost.php?p=8921414&postcount=1

The first link is Vassili's comments with a link to BLUNTRUTH4U's test. The second is Ankerson's ranking results. It isn't a bad steel, I was just wanting more wear resistance than what I observed. We all have different desires for how our knives work.
 
beatdown78 said:
With toughness think more of the steels ability to absorb energy and deform without breaking. I always used to think of it this way; imagine trying to break a green branch off of a tree, the wood bends and bends and bends without actually breaking. That is toughness. It is able to deflect more without breaking. Prying with a knife is very similar.
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Actually, what you're describing is strength, not toughness. Toughness is a measure of an alloy's ability to absorb impact. Strength is a measure of an alloy's ability to deform (bend) without breaking or taking a set.

Souce: http://www.zknives.com/knives/articles/knifesteelfaq.shtml
 
I think the term "toughness" is too vague. We really should break things down to the different forces and behaviours. Plastic deformation, elastic deformation, tensile strength, compressive strength, and I guess impact vs static load makes a difference as well.
 
Keeping the terminology of steel properties straight can be daunting. I see "toughness" and "strength" confused for each other all the time. That's why I keep going back to Joe Talmadge's definitions. Anything beyond that is too granular for me. (Pun intended! ;) )
 
These posts are all very, very interesting.

And somewhat confusing, too.

Recently, I watched one of the Cold Steel videos of the Master Tanto with San Mai III VG-1 steel, with the knife in a vise, and a long pipe over the handle, bending, bending, bending.... until what looked (if memory serves) like a more than 90 degree bend. It was incredible. That is the kind of flex/strength/toughness/whatever it's called, that I find to be very interesting.

Obviously, there are other steels with different heat treatments and so on that are capable of that sort of performance. Are the S30V steels good to go for that sort of performance? What other steels are up to that kind of abuse?
 
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