Blade Steel 101?

[azreloader]

Could any of you knife maker/metalurgists out there give us a crash course on the science of Blade Steel and what various properties each of the different types of steel have?

I view hundreds of descriptions with numeric designations like Carbon V, 440C, 420, N690, etc.

What does it mean to me as a knife owner?:dunno:

[5KNIVES]

azreloader,

AAARRRGGGGHHHH,

sorry just had to get that off my chest, nasty question. Hoped someone else would tackle it and look foolish, but no one took your bait, and courtesy requires some kind of answer, so that's what you get. Some kind of an answer. I'll do my best, but I'm having to remember back a lot of years.

Remember the cast iron course takes about 100 years, and then you get to start on steel. And I'm not up to date on all the current designations.

Good knife steel requires a balance between hardness (to hold an edge) and toughness (bend, don't break or shatter) getting that balance is the tricky part. You also want good corrosion resistance

The so-calles stainless steels are corrosion resistant, usually because of the addition of chromium to the melted steel. Steel is basically iron with carbon and other metals added. Tiny, tiny variations in the additives can cause great differences in the end result.

Carbon Steel is not very corrosion resistant at all, but can have very good characteristics for a knife blade. 1095 carbon is an old standby, and a lot of people prefer it to anything else. It's tough, takes a great edge, holds it pretty well and is easy to resharpen. Whatever steel Cold Steel calls Carbon V is (probably for a % of Vanadium) really is an improvement, supposedly the same as Western used in their older knives, as is Case Chrome Vanadium or CV. Your trusty issue Ka-Bar (everybody has one) is probably 1095, as are a lot of meat processing knives

General knowledge up untill about 15 years ago that stainless could not make a really good knife blade, some still think that, I havent decided yet.

Argument is that the chrome used in stainless changes the grain pattern(clumps up), and you simply cannot get the same degree of sharpness,

Yet Opinel makes a carbon blade and a stainless blade and there doesnt seem to be any real difference between the two in use. The Finns, Norwegians and Swedes use a lot of Sandvik stainless and it makes a great knife steel.

The 440 stainless series we see on a lot of cheaper knives here, depending on the letter, ranges from poor to okay to pretty good.

Heat treatment (hardening and anealing) changes the final result greatly. The harder the result, the better it will hold an edge, but the harder it will be to sharpen. The older Buck knives were really hard, and it took a trip to the factory, or diamonds to sharpen them properly, way hard, plus they had their own edge geometry, couldnt duplicate it with a flat stone.

AUS 6, AUS 8 and AUS 10 are good stainless knife steels, and the higher the number the better it is.

IIRC, it's the 440 A and/or J that you really don't want, I cant get to my references and I honestly dont recall, I'm sure someone here will correct me if I'm wrong.

N690, sorry, haven't a clue, someone will though.

Personally I'm fond of the carbon blades, and the nordic stainless, but i like the AUS series also.

If you sharpen you knife and don't use it for a month or so, the stainless blade will be just as sharp as when you put it away, the carbon blade won't.

One thing, the term "High Carbon" is meaningless, any time a Mfr. wont name the steel I get suspicious.

Easiest way to get a feel for the good knife steels is to check the web sites and catalogs for the various makers and custom makers. If they are bragging about their steel on their higher priced knives, chances are it's pretty good stuff. Some fad and fashion here though, D2 tool steel is currently popular in some quarters.

Hope this helps a little, or at least points you in a good direction.

Now all of you who really do know the subject can correct me . I'm not to old to learn, yet.

[azreloader]

5KNIVES,

Thanks for the response. I know it's a tough subject, but it helps to know what drives the price of some knives beyond the $200 range. (not counting custom, hand made knives)

I know more than I did and maybe we'll get some additional input from others.

Thanks again.

AZ

[HDR]

Metallury is a complex science. I do design engineering and although I can usually choose both the correct material and Heat Treat, I've been around enough real metallugists to know to avoid getting in too deep..

For example, CS is or has quit using AUS 8 because the edge is so smooth it lacks a good cutting "tooth." Plus they are so hard that the point is brittle, I believe there's been a lot of chat on the Benchmades ATS-34.

Here's an interesting read..
http://www.physics.mun.ca:80/~sstamp/knives/blade_testing.html

BTW
AUS is a type of stainless, if you want to get deeper search for Austenitic Stainless Steel

http://www.nationalboard.net/classics/classic18.html
http://crswnew.cartech.com/wnew/techarticles/TA00037.html

http://crswnew.cartech.com/wnew/techarticles/TA00037.html

why the points break:
http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=5004838

;)

[azreloader]

So if I'm getting this right, the addition of rust resistant compounds to the metal reduces the edge holding ability of the blade.

I guess the ultimate decision depends on how often and for what you are using your knife.

Just more reasons to buy a bigger variety of all kinds of knives. :up:

[5KNIVES]

HDR,

Thanks for the info and the links.

A long time ago I was an EE who found himself teaching Welding, Soldering and Brazing. And frantically scrambling to learn enough Metallurgy to keep from looking like a complete idiot.

What I learned was that , as you say, the field is complex. I wasn't really kidding about the 100 year iron course, thats what it looked like it would take me to really be knowledgeable.

Well I learned enough to get by, and enough to know I knew enough to be dangerous. Thats why I'm reluctant to say much on this topic, dont care about looking foolish, but I do care about giving someone a bum steer.

Thanks for the heads up on AUS 8, I was just getting ready to buy a CS in AUS 8, now I won't.

azreloader

" if I'm getting this right, the addition of rust resistant compounds to the metal reduces the edge holding ability of the blade."

That seems to be the general consensus. But again there are some great performing knives in stainless. You wouldnt believe how a $12 Mora can perform without experiencing it.

" the ultimate decision depends on how often and for what you are using your knife."

FWIW, I think so. I carry a case stockman in CV in my pocket for daily use. But the BK-7 in the car has a stainless stockman in the "sharpener" pouch on the sheath.

"Just more reasons to buy a bigger variety of all kinds of knives. "

By God I think he's got it ! He has ! He's really got it !

Now you're really in trouble, you're hooked, addicted, you've anounced your own doom. Big knives, small knives, expensive knives, cheap knives, fine knives, useful knives even useless knives and strange objects that look like knives, sort of ! More knives, I need more knives!

Pretty soon, you won't count them either, you'll just put them in a box and weigh the box(s).

Good luck my friend, have fun.

[2X4]

Disscussion over the same topic goin on over at the frug's

Check this one out AZ

http://home.cc.umanitoba.ca/~umschm08/aboutsteel.html

[Optimus Prime]

Man this is a great thread, as a newbie to the "riddle of steel" this helps out.........alot!

Good link 2X4! Now I know what some of the steel I carry is.

[azreloader]

2x4,

Thanks for the Link. It is very helpful and easy to understand. Still don't know much more about the N690 steel. Guess it's fairly new.

Great info guys. Thanks!

[2X4]

Yup good link np.

I too have tried to read up on the n690 and havent found much. I think I might have to break down and go the the bookstore.

[azreloader]

Here's what Dave's Knife World has to say about "Extrema Ratio" knives and their steel:

"A proprietary Cobalt Stainless steel, known as N690, was selected for its exceptional qualitites and is used to produce all blades. This steel, which comes from Austria and is manufactured by a small highly specialized steel plant, features high resistance to corrosion and wear, keeps a sharpened edge for longer, can be easily polished and features also high levels in hardness, over 60 HRC."

[5KNIVES]

2x4 and azreloader,

Good current information, thank you gentlemen!

[ZEKE/PA]

Hey guys.
It's really simple.
An old die steel known as D-2 is the best there is for a knife blade PEROID.
Regards, Zeke

[azreloader]

Nuther link to some good info on steel differences.

http://www.crkt.com/steelfct.html

[Optimus Prime]

That is a good link, I am looking at getting several of the CRKT knives and that is very informative. ;)

[EndGame]

Here's a link to one of the best places to learn a bit about the different types of knife steel:

http://www.bladeforums.com/features/faqsteel.shtml

[5KNIVES]

A.G Russells website at

www.agrussell.com

has a good page comparing the make up of current knife steels. You can see that a minute change in the carbon, chrome, etc. componenet can greatly affect the quality of the steel.

A.G. handles most major brands, but you'll notice only some models. He's one of the old time knife makers, and his record for quality and Customer satisfaction in simply Outstanding.

You can learn a great deal just reading his website and what he has to say about each knife, maker, or steel. It's worth a visit.

[azreloader]

5KNIVES,

I found that site while doing a search recently. Only the best stuff. Found a couple items to add to my wish list.

This thread has been far more informative and productive than I imagined. Thanks to all who provided info & links to info.

I learned a lot but feel I've just scratched the surface.;)

[HDR]

Originally posted by azreloader
I learned a lot but feel I've just scratched the surface.;)

True it's a huge field, each steel has it's advantages and disadvantages. However let's not forget that it's a very competitive business, so advertising enters and we have info overload..

Take a look thru the magazines, can those knives ALL be carried by SOCOM personnel? ;)

Knifemakers test a blade, for example a blade is mounted in a machine, then tested to see how many times can it cut manila rope before dulling. They test 20 of each type and average it, one blade makes 850 cuts and the newer steel makes 910.. So the new steel is better..

But never forget, the old mildsteel Ka-Bars and others keep on trucking..