Blade steels - what's wrong with improvement?

[Ankerson]

Didn't ask that. Also, the steels of which I'm critical have large amounts of vanadium versus large amounts of Wolfram or moderate amounts of niobium and they also usually have very high ( > 1.25%) levels of carbon, too. Most of them are intended for use as die-cutters, extruders, and punches, not pocketknives or kitchen knife.

VERY FEW steels overall were ment from development to be used in knives, MOST have been adapted into knife use over the years.

That includes almost all of the most popular carbon steels....

Like has been mentioned before the knife industry is a very small part of the steel industry as a whole....

So I am not so sure about that argument.....

 

[Twindog]

I’m not a metallurgist or an expert of any kind, but I thought it might help to summarize some data off Crucible’s website. The link is at the bottom.

As a general matter, knife blades need steel with three properties in order to support the blade and edge geometry necessary for whatever cutting task the knife is designed to address:
1) The steel has to be tough to withstand cracking, chipping and breaking;
2) it has to be strong enough to withstand deformation (basically a function of hardness);
3) and it has to have good wear resistance so the edge doesn’t wear down quickly.

All steels have carbon added to get the hardness up to about 60 HRc. It generally takes about 0.5 percent carbon to get the steel that that hardness. But additional alloys and production methods can give steels used for knives significant advantages over simple carbon steels. Super steels and advanced production methods can do even better.

For example, by adding vanadium to a steel with excess carbon (more than 0.5 percent), the vanadium will combine with the excess carbon and form vanadium carbides, which have a hardness of 82-84 HRc. These carbides will give the steel greater wear resistance and also protect the steel matrix itself from wear.

But with traditional steelmaking processes where steel solidifies slowly, too much vanadium will begin to clump together, weakening the steel and making it more difficult to grind. Traditional steel is limited to about 3 percent vanadium before these problems become serious.

The power steel process of many super steels keeps the carbides uniformly distributed within the steel by atomizing the steel and allowing it to cool quickly. This process prevents the carbides from clumping and allows steelmakers to boost their steel’s wear resistance without losing toughness or while keeping toughness to acceptable levels. The carbides formed in this process are extremely small – 2 to 4 microns, compared to 50 microns or larger with traditional steelmaking processes.

So the power steel process gives us knife blades with 4 percent or more vanadium that have incredible wear resistance and still retain good toughness. The high-speed steels M2 and M4 have almost the same chemistry, but M4 has nearly double the wear resistance because it has 4 percent vanadium vs. 2 percent for M2. M4 can be made only by the powder process. Super steel M4, compared to the traditional O1 steel, is tougher and much more wear resistant. It’s also more stain resistant. O1 is easier to make into a knife.

The powder process can be a win/win/win/win. For example, compared to D2 tool steel made conventionally, powder CPM D2 is stronger, tougher, more wear resistant and easier to manufacture into a knife. The stainless super steel S35VN has the same advantages over the conventional stainless 440C.

http://www.crucible.com/pdfs/SelectorKnifePocketRotatedCrucibleLLC.pdf

I took most of this from a Crucible website:

http://www.crucibleservice.com/eselector/general/generalpart1.html

 

[thombrogan]

It's a different point than saying anyone who hates gosh-awfully inappropriate steels for such knives is the same as being like that violent albino guy in that Tom Hanks movie (can't remember if it was Da Vinci something or Splash...). Though I did old-timey it by calling tungsten 'wolfram.' At least I didn't call niobium 'columbian' or 'that danged stuff used for those belly-button rings on the stripper ladies.'

Wait a moment. Maybe that last point would tip the tides. Strip steels, stripper-lady steels, and shock steels - oh my!

 

[Ankerson]

I’m not a metallurgist or an expert of any kind, but I thought it might help to summarize some data off Crucible’s website. The link is at the bottom.

As a general matter, knife blades need steel with three properties in order to support the blade and edge geometry necessary for whatever cutting task the knife is designed to address:
1) The steel has to be tough to withstand cracking, chipping and breaking;
2) it has to be strong enough to withstand deformation (basically a function of hardness);
3) and it has to have good wear resistance so the edge doesn’t wear down quickly.

All steels have carbon added to get the hardness up to about 60 HRc. It generally takes about 0.5 percent carbon to get the steel that that hardness. But additional alloys and production methods can give steels used for knives significant advantages over simple carbon steels. Super steels and advanced production methods can do even better.

For example, by adding vanadium to a steel with excess carbon (more than 0.5 percent), the vanadium will combine with the excess carbon and form vanadium carbides, which have a hardness of 82-84 HRc. These carbides will give the steel greater wear resistance and also protect the steel matrix itself from wear.

But with traditional steelmaking processes where steel solidifies slowly, too much vanadium will begin to clump together, weakening the steel and making it more difficult to grind. Traditional steel is limited to about 3 percent vanadium before these problems become serious.

The power steel process of many super steels keeps the carbides uniformly distributed within the steel by atomizing the steel and allowing it to cool quickly. This process prevents the carbides from clumping and allows steelmakers to boost their steel’s wear resistance without losing toughness or while keeping toughness to acceptable levels. The carbides formed in this process are extremely small – 2 to 4 microns, compared to 50 microns or larger with traditional steelmaking processes.

So the power steel process gives us knife blades with 4 percent or more vanadium that have incredible wear resistance and still retain good toughness. The high-speed steels M2 and M4 have almost the same chemistry, but M4 has nearly double the wear resistance because it has 4 percent vanadium vs. 2 percent for M2. M4 can be made only by the powder process. Super steel M4, compared to the traditional O1 steel, is tougher and much more wear resistant. It’s also more stain resistant. O1 is easier to make into a knife.

The powder process can be a win/win/win/win. For example, compared to D2 tool steel made conventionally, powder CPM D2 is stronger, tougher, more wear resistant and easier to manufacture into a knife. The stainless super steel S35VN has the same advantages over the conventional stainless 440C.

http://www.crucible.com/pdfs/SelectorKnifePocketRotatedCrucibleLLC.pdf

I took most of this from a Crucible website:

http://www.crucibleservice.com/eselector/general/generalpart1.html

OH no, now you really did it.... ROFL

The steel companies can't possibly know anything about steel or how it used or what it's for in any way, and even less about performance...

I mean they only develop it and produce it, what could they possibly know? LOL

Or even the Scientists on staff can't possible know anything......

Only a very few people actually know anything about steel and the best way to use it.... I thought everyone knew that..... ROFL.....

I mean really..... LOL

 

[thombrogan]

Knowledge in material science doesn't require capitalizing "scientist" in mid-sentence merely because the person has something to sell you and wants you to feel good about buying what is sold. With S35VN supposedly being superior to S30V (it's progress! The Scientist in sales said so), hyping up its improvement over 440C diminishes what would otherwise be the roaring sound of its epicness.

And when it comes to cutting very large amounts of cardboard by hand (because using a knife is an improvement over a dedicated shredding machine - the Scientist said so!), getting a high end knife in Vanadis 4, Vanadis 10, S125V, or 10V is such an improvement over a generic, serrated steak knife with non-martensitic steel for the same task.

But what if it's the cardboard whittling/boar-skinning/arm-hair shaving jamboree that day? Surely the Scientist from sales shall save us! Funny that the saintly Scientist from sales is always hawking one high-vanadium alloy or another when there's a whole world steels with little or no vanadium that make so many things easier for the knife user and knife maker. Unfortunately, the metallurgists who've published such data are not the Scientist from sales and don't offer a frequent buyers' club, so they must be against progress, you know...

 

[Ankerson]

Knowledge in material science doesn't require capitalizing "scientist" in mid-sentence merely because the person has something to sell you and wants you to feel good about buying what is sold. With S35VN supposedly being superior to S30V (it's progress! The Scientist in sales said so), hyping up its improvement over 440C diminishes what would otherwise be the roaring sound of its epicness.

And when it comes to cutting very large amounts of cardboard by hand (because using a knife is an improvement over a dedicated shredding machine - the Scientist said so!), getting a high end knife in Vanadis 4, Vanadis 10, S125V, or 10V is such an improvement over a generic, serrated steak knife with non-martensitic steel for the same task.

But what if it's the cardboard whittling/boar-skinning/arm-hair shaving jamboree that day? Surely the Scientist from sales shall save us! Funny that the saintly Scientist from sales is always hawking one high-vanadium alloy or another when there's a whole world steels with little or no vanadium that make so many things easier for the knife user and knife maker. Unfortunately, the metallurgists who've published such data are not the Scientist from sales and don't offer a frequent buyers' club, so they must be against progress, you know...

Thanks for confirming my last post, I knew someone would....

 

[thombrogan]

The same condescending wink when you told me no one in Japan used Swedish steels and then you didn't even recognize the makers when I shared their easily-googled names with you. You sure do prove a lot of things, don't you?

I brook no grudge with Bohler-Uddeholm, Carpenter, Crucible, or Timken selling as much as they have to whomever will buy and I'm grateful that, as sellers of steels, they have metallurgists on staff to explain how to use their products and which behaviors to expect as well. They aren't the ones making your claims. You're the only one here making it look like only mystic revelation would let someone know that 5 is less than 20. And then adding winks and "LOL" and "ROFL."

So, for further edification: 14C28N r0xx0rz n CPM-10V suxx0rz 4 teh nyyfz! kthxbai

 

[Ankerson]

The same condescending wink when you told me no one in Japan used Swedish steels and then you didn't even recognize the makers when I shared their easily-googled names with you. You sure do prove a lot of things, don't you?

I brook no grudge with Bohler-Uddeholm, Carpenter, Crucible, or Timken selling as much as they have to whomever will buy and I'm grateful that, as sellers of steels, they have metallurgists on staff to explain how to use their products and which behaviors to expect as well. They aren't the ones making your claims. You're the only one here making it look like only mystic revelation would let someone know that 5 is less than 20. And then adding winks and "LOL" and "ROFL."

So, for further edification: 14C28N r0xx0rz n CPM-10V suxx0rz 4 teh nyyfz! kthxbai

You were just the 1st to reply to the last post....

I am waiting for the other shoe to drop...

Since we have been down this very same road in the past and more than once....

Watch and see what happens.....

 

[james terrio]

Let's discuss the topic, not each other, gentlemen. This is an interesting and helpful thread... it would be a shame to get it locked.

 

[thombrogan]

If we must divide in hostile factions
Let it be regarding carbide fractions
And every once dull epithet
Gets resharpened on stones of whet (or WEPS or EdgePro or Sharpmaker....)
Resistant wear and brittle failure
All whilst outcussing most sailors
Though back and forth we curse and taunt
Who cares? Just use the steel you want!

 

[chiral.grolim]

... there are better carbide formers for knife steels than vanadium and better alloys for knives than the higher carbon higher vanadium ones being hyped...

Let's keep this focused, yes?

It has already been pointed out that most steels were not developed for knife use. 52100 is "ball-bearing" steel and iirc 440C was created as a stainless alternative.

What are you suggesting as a "better carbide former for knife steels and better alloys"? I'd like to read about this and why you think this... The entire point of innovation is to produce improvements upon existing technology. Now i can think of many very key examples where technological innovation has done more harm than good, or even ONLY harm ... But I honestly have no idea what you are thinking of in regard to knife steels. Please share.

 

[singularity35]

Why use an edge at all? Just push or swing harder.

Surely you're not saying the difference between a well formed 15dps edge and a lower one is the same as no edge and a well formed 15 dps one?

 

[thombrogan]

It has already been pointed out that most steels were not developed for knife use. 52100 is "ball-bearing" steel and iirc 440C was created as a stainless alternative.

Why is your above-quoted statement a point of contention? I'm not arguing that all steels developed for non-cutlery uses shouldn't be used for cutlery any more than you're arguing that only non-cutlery steels should be used for cutlery.

What are you suggesting as a "better carbide former for knife steels and better alloys"? I'd like to read about this and why you think this... The entire point of innovation is to produce improvements upon existing technology. Now i can think of many very key examples where technological innovation has done more harm than good, or even ONLY harm ... But I honestly have no idea what you are thinking of in regard to knife steels. Please share.

Tungsten. It's better for knives because the carbides it makes are not only very hard, but also quite small.

 

[cujobob]

I love change and modernity! With that said i personally dont need an Elmax blade to cut my peach at work or that little piece of silk hanging from my tie or the cord that I use to keep my tomato plants from falling down in the summer. I dont make any illusion to what I do with knives vs my two box cutters,, heavy duty cutting shears, camp axe etc
..etc... I also like with the regular steels I can sharpen anything from dull to very sharp in less than a few minutes. Btw 440a is terrific for very light duty work! I have some Chinese knives from rough rider that can cut the crap out of a piece of looseleaf like nobody's business. Also great for cutting loose threads from my shirt, mail, tape on boxes you know like normal regular everyday cutting tasks.

Modern steels are still better here. Modern inexpensive Sandvik steels will take a great edge and are incredibly easy to sharpen. The expensive higher end steels are going to be better for long days of cutting obviously but these are all better because our understanding of metallurgy and edge geometry keeps evolving.

 

[McVeyMac]

Over my lifetime, there have been incremental improvements in blade alloys, and very few, if any, quantum advancements sans powder technology. And even here, improved powder alloys only make small incremental advancements at a time. However, over the past half century, blade steels have improved greatly.

So to me it is not about being a steel snob, but about having the best properties possible in the steel for the application. Sometimes this is the latest "supersteel." In 50 years, forums will be having these same arguments, all the time wondering how all those people got along in the early 21st century with that crappy steel in their blades.

 

[Twindog]

Tungsten. It's better for knives because the carbides it makes are not only very hard, but also quite small.

Just FYI:

Hardened steel: • 60/65 HRc
Chromium carbides: • 66/68 HRc
Molybdenum carbides: • 72/77 HRc
Tungsten carbides • 72/77 HRc
Vanadium carbides • 82/84 HRc


An increase of 1 degree Rockwell equates to an increase in hardness of about 10% as well as an increase in edge-holding ability. (From Shun Knives)

 

[chiral.grolim]

Tungsten. It's better for knives because the carbides it makes are not only very hard, but also quite small.

Hardened steel: • 60/65 HRc
Chromium carbides: • 66/68 HRc
Molybdenum carbides: • 72/77 HRc
Tungsten carbides • 72/77 HRc
Vanadium carbides • 82/84 HRc

An increase of 1 degree Rockwell equates to an increase in hardness of about 10% as well as an increase in edge-holding ability. (From Shun Knives)

As Twindog indicates, Tungsten (W) forms softer carbides than vanadium, but it is worth noting that they are also LARGER, presenting a reduction in wear-resistance and strength and toughness. Sooo... why tungsten rather than vanadium? Are we also switching from iron to titanium? I would like to read up on what makes you think tungsten is better and the like.

 

[thombrogan]

it is worth noting that they are also LARGER, presenting a reduction in wear-resistance and strength and toughness.

Well that's the fly in my ointment, now isn't it? Even so, the knife steels I monkey with that have tungsten getting thick as thieves with carbon (Blue #2, Blue "super," and 1.2552) tend to hold finer edges with higher polish than steels with molybdenum or vanadium in that role. I wonder how variable in size those suckers are; why they let me do things I couldn't do with SGPS; and if some afi's say the white paper steels get sharper than the blues for that very reason.

 

[chiral.grolim]

Well that's the fly in my ointment, now isn't it? Even so, the knife steels I monkey with that have tungsten getting thick as thieves with carbon (Blue #2, Blue "super," and 1.2552) tend to hold finer edges with higher polish than steels with molybdenum or vanadium in that role. I wonder how variable in size those suckers are; why they let me do things I couldn't do with SGPS; and if some afi's say the white paper steels get sharper than the blues for that very reason.

Hey, if those the knives you have in those Aogami steels are easier to sharpen to the edge you need and last how you need them to :thumbup::thumbup:
Perhaps the other steels which are better on paper would be better in another user's hands, but from steel manufacture and heat-treatment to blade design and geometry to your own sharpening technique and use, there are a LOT of factors which come into play. It could be that the learning curve for getting the edge you want is higher on the knives using those other steels *shrug* So it doesn't matter what would work best in someone else's hands if what you are using works so well for you :thumbup: Keep it up.

 

[Gator97]

Well, a lot happened in last few days. For one, what's the splitting maul edge that it compares favorably to 12-15DPS anyway

Even so, the knife steels I monkey with that have tungsten getting thick as thieves with carbon (Blue #2, Blue "super," and 1.2552) tend to hold finer edges with higher polish than steels with molybdenum or vanadium in that role.

Tungsten, because it's so heavy, is rather misleading. In reality is can form fewer carbides than lighter alloys, V, Mo, Nb, etc. All because W atomic mass is 184 and the rest are 2-3 or even lighter. That's fewer or more atoms to form carbides.
Take Aogami Super, by mass percentage, Tungsten is 2.0 - 2.50%, Vanadium ONLY 0.30%-0.50%, which is, 5-6 times more Tungsten, by mass at least, but carbides are formed atom by atom. Means, W will form less, because there's about 3 times less of it by atomic count. - Aogami Super composition in atom count per 1000
In other words, 2.5% tungsten is not that much, steel with 2.5% Vanadium would form 3 times more carbides compared to that. Even 18% Tungsten would be insufficient to outnumber 7% V...
In 1.2552 steel composition, even though V is rather trace amounts 0.50% at best, and Tungsten is 2.5%, still, there's not even twice the Tungsten atoms in the alloy compared to Vanadium.

Other than that, there's two types of Tungsten carbide, WC and W2C. Former is softer compared to Vanadium Carbide (VC), later W2C is actually harder, but not so sure if it forms in tool steels based on their HT.