blue steel vs white steel??

D

DavidL41

Joined
Oct 12, 2014
Messages
160
From what i hear from murray carter white steel is superior to blue steel because it holds a sharper edge. Is this typical for blades that have added elements that increase durability, trade off sharpness.

In general how much longer do blue steel and super blue last compared to white?
 
David, I'm surprised no one has chimed in yet. I can offer some limited experience with both Blue2 and White2. Super Blue just being a higher alloyed and higher carbon version of Blue1.

White steel can indeed take a sharper, keener edge than Blue or SBlue. The reason being is there is very little to no alloying present, so the matrix will consist of cementite carbide. Iron and carbon...that's it. I think White does have some small Silicone as well. But being that the matrix structure of White is so fine...it can take a screaming scary sharp edge. That amazingly scary edge will disappear relatively quickly to give a nice user edge that will last and last.

Blue has alloying....particularly Tungsten. The Tungsten carbide formation of Blue steels will not allow the SAME exact sharpness level of White...because the Tungsten carbides are somewhat larger than the surrounding cementite matrix. However, while not quite as sharp as White, Blue steel certainly gets crazy sharp. The edge you sharpen to lasts for quite some time. Wear resistance is slightly better with Blue over White.

Here is the thing. White steel takes a very skilled forger to master. A person could spend a lifetime learning the details of White steel and overcoming it's difficulties in forging. Blue steel is MUCH more forgiving in forging and heat treating. So when someone like Murray, who has worked both steels, says that they like White better, I think much of that is because of the time and effort learning it.

Don't get me wrong, tho. A simple steel such as white, that has no carbide bearing elements in it except the carbon and iron itself, is extremely capable in the kitchen. But if a chef's knife in white steel were to be placed against a chef's knife in blue steel cutting very abrasive material (heat treat being the best, and geometry equal) such as rope and the like, the carbide bearing blue steel will/should outlast the white steel. But in the kitchen we rarely cut anything even remotely abrasive.

Another thing to consider is edge stability. White has the advantage due to it's smaller matrix structure. As in torquing the edge....carbides in an edge do indeed weaken the edge when it comes to lateral forces! ALWAYS a trade off!

Super Blue should have slightly added toughness and wear resistance over regular Blue 1 and 2. It has a higher W count, higher C count, and added V as well. More carbides than regular Blue steels.
 
DavidL41 said:
From what i hear from murray carter white steel is superior to blue steel because it holds a sharper edge. Is this typical for blades that have added elements that increase durability, trade off sharpness.

In general how much longer do blue steel and super blue last compared to white?
Click to expand...

Isn't this the same thread? www.bladeforums.com/forums/showthread.php/1246581-Regular-steel-vs-quot-special-steels-quot?

To quote my post there:
The determining factor in attainable sharpness for a given substances is attainable hardness which is determined by carbon content in steel, and by grain-refinement, accomplished through specific alloying elements and HT. Blue#2 and White#2 have the same carbon content, but Blue's tungsten (W) content allows for a more refined grain = sharper edge at same hardness, and more abrasion resistance in that edge = Superior. White#1 & Blue#1 have higher carbon content than the previous 2 but the same principles apply, and Super Blue has even more carbon with grain-refiners and carbide formers to support the matrix = even higher attainable hardness with same grain-size and increased carbide content = higher attainable sharpness and abrasion resistance.

THAT is what the composition tells you - White steel canNOT achieve higher sharpness than Blue unless comparing White#1 to Blue#2. Now that might not make a difference if you can't actually achieve that superior sharpness in your sharpening - the steel doesn't automatically have that sharpness, you still need to get it there through proper equipment and technique, THAT is the limiting factor. A good maker using White#2 might achieve a thinner, longer-lasting edge than a lesser maker using Super Blue.
Regarding ease of sharpening, this again depends on equipment and technique. Using harder/sharper abrasives (e.g. diamond, SiC), the abrasives are so much harder than the steel-matrix, with or without carbides, that it takes no longer to abrade away the metal from one vs another. With inferior equipment, you may experience a difference in sharpening the resistant material vs the weaker one.
Click to expand...

Again, white steel canNOT take a sharper, keener edge. Also, the tungsten carbides (WC and W2C) are NOT notably larger than cementite (Fe3C), nor is the grain of the steel matrix, indeed the alloying elements in blue steel reduce the grain size. The tungsten carbide present in blue steel presents twice the stiffness of what white-steel can achieve = keener edge in addition to the added wear-resistance. theoretically, blue steel can be made sharper than white steel but as I said before, it doesn't do that by itself, it requires proper tools and technique to achieve. What white steel can do is achieve that keen edge with simpler (softer) abrasives than a steel with harder carbides. The hard carbides resist cutting (abrasion) and so require a harder abrasive (e.g. CBN, SiC, diamond) to shape them to a fine apex. As to lateral torquing of the edge, a harder Blue will resist deformation better than a softer white, but at the same hardness you're unlikely to notice a difference. If the white steel was not properly HT'd, cementite propagation can result in high brittleness (i.e. low stain fracture) along large areas. This can be avoided by leaving it softer, but then it deforms much more easily at the apex though it doesn't fracture as readily. Keep in mind that a deformed apex (folded, squashed) is more dull than a fractured apex with similar depth of damage.

So in general, Blue steel is superior to white steel in HT, potential toughness (though neither is all that tough), wear-resistance, and also attainable sharpness but it requires more skill and better equipment to attain that sharpness, and it tends to be more expensive. A good maker with White steel can create a better knife than a poor maker with Blue steel.
 
Last edited:
Anyone know how big the cementite particles in White are vs. the tungsten carbides in Blue, as in actual measurements?
 
me2 said:
Anyone know how big the cementite particles in White are vs. the tungsten carbides in Blue, as in actual measurements?
Click to expand...

Tungsten-carbide tends toward 1 - 8um aggregates which can be shaped to an apex diameter ~0.005 um due to high hardness (that's the carbides themselves, not the martensite which is much softer/less stable). Cementite particle size depends greatly on HT but can achieve 1-8 um particles (comparable) if the maker can avoid aggregation along the grains (problematic), and theoretically should be able to attain an apex ~0.010 um (again, the particles themselves can be shaped that fine). But the martensite (most of the apex volume) is too soft to achieve such low diameters, limited to ~0.5 um (depending on hardness) which is narrow enough for most applications.
 
Well....I stand corrrrrrrrrrected. But my real world experience has been exactly what I said. I have diamond stones and water stones. I can make white steel so sharp it is indeed noticeably sharper than Blue steel, or the O7 steel from germany which is very similiar. Compositions and carbide size are important...but in the real world....this is what I and many others experience. White steel taking a sharper edge.
 
samuraistuart said:
Well....I stand corrrrrrrrrrected. But my real world experience has been exactly what I said. I have diamond stones and water stones. I can make white steel so sharp it is indeed noticeably sharper than Blue steel, or the O7 steel from germany which is very similiar. Compositions and carbide size are important...but in the real world....this is what I and many others experience. White steel taking a sharper edge.
Click to expand...

This is true, as I stated it may take a sharp edge more easily. Keep in mind that the sharpest edges are achieved on essentially pure carbide blades, i.e. ceramic, but "in the real world" most users struggle to achieve these amazingly sharp edges because of equipment and skill, and indeed steel can achieve a sufficiently sharp edge that few would notice a real advantage to the ceramic blade in terms of sharpness or even edge-retention and may instead note a disadvantage in fragility and maintenance. So if White works better for you, :thumbup: I like 420HC and SR101 in most of my knives because it is cheap and easy to maintain, does what i need, makes me happy :)
 
Do youhave any references for the hardness/attainable sharpness information? I had figured it was the dual phase nature of steel that limited the edge radius. The sharpest I'd heard of were in obsidian which I figured was not only single phase, but amorphous as well.
 
me2 said:
Do youhave any references for the hardness/attainable sharpness information? I had figured it was the dual phase nature of steel that limited the edge radius. The sharpest I'd heard of were in obsidian which I figured was not only single phase, but amorphous as well.
Click to expand...

Obsidian is primarily silica and its amorphous structure allows it to fracture conchoidal to a sharpened edge as lows as 3 nm ... but it is still silica crystals at that edge (order over very short distances) and the attainable sharpness is limited by the size of those crystals and also their density/hardness. Diamond and tungsten-carbide are much harder/denser and can also fracture to produce similarly sharp edges which can be used to lap/abrade/lathe other materials at sub-micron levels, e.g. microtome blades (I'm trying to find my original WC reference, but here is one for 5 nm apex diatome blades http://www.tedpella.com/diamond_html/diamondk.htm, and here is a paper that shows the sub-micron scratch-pattern produced in tooth-enamel from a carbide blade http://www.sciencedirect.com/science/article/pii/S0889540696701634). Keep in mind what abrasion of WC or diamond is, namely cleavage. You can shape these particles. But at sizes that small, the ability to hold a shape, especially one to be used for cutting, becomes a matter of density/hardness to resist deformation. Tungsten-carbide is ~2X stiffer/harder than cementite and 3-4X stiffer than martensite - THAT is what allows it to achieve such sharpness. But again, the carbides make up a small percentage of the volume in the apex, so attainable sharpness is largely limited to the martensite and how hard it can be made - recall Verhoeven's sharpening experiments of hard vs soft steel razor-blades.
 
Some would argue that these steels big advantage are they are very pure and consistent in their composition. According to Japanese standards, a high quality forged monosteel blade (honyaki) is the hardest to forge. Laminated 2 piece blades using the hard steel and "iron" are easier. That is just the opposite of the conventional wisdom here in the West. Having watched Murray Carter videos of him forging the tractional Japanese way, I wonder if that is because they do things when forging that would make us cringe, like pounding on a cold blade with a hammer? That makes me wonder if these Hitachi steels are formulated specifically to survive, so to speak, the archaic forging methods that traditional Japanese smiths use?
 
me2 said:
How are those sharpened? I see they offer a service.
Click to expand...

It is no different than sharpening/polishing any carbide material, which is really no different in principle than shaping steel: rubbing the flat bevel against the sharp corners of abrasive particles, e.g. bound diamond dust. A small particle scratches/gouges the plane and further particles gouge/crack away thus weakened material. This is no different than for martensite or even wood - as long as you have a particle of appropriate size and sufficient sharpness and hardness, you can shape as desired via careful application.
 
1095 is very similar to White steel in that it is basically only carbon and iron. some silicone I think. As a matter of fact, when you send your 1095 or White steel to Peters for heat treating, they use the same procedure for both. As jdm stated earlier, the big thing with the Hitachi steels isn't that they are superior, but they are a very clean steel (very low P and S values), and they are extremely consistent batch to batch. CANNOT say that at all about 1095. And White does have more carbon than 1095, of course. White 1, White 2, White 3 all descending carbon contents.

Not being familiar with SK5, I had to look it up. Two totally different versions of SK5. One of them being a high speed tool steel. The other, however, is closer in comp to White steel than I would have guessed. It is basically 1095 with a very small touch of Cr (0.0%-0.3%) and a very small touch of Ni (0.0%-0.25%).
 
Again, thanks for the information:thumbup: I hate to derail the thread, but my curiosity came about due to a $10 knife. The Hultafors GK is made with an unidentified steel. A little 'net research brought up that it was Japanese steel (the blades are handled in China). Then, I heard/read it was SK5, and that was Hitachi White. All very round about and questionable, but it peaked my curiosity. The knife has great steel, quite tough, even hardened a bit high, as it is. Also, my CS Gurkha khuk is SK5 and, while less hard, is impressive IMHO. It was interesting to hear your thoughts on it. Thanks again guys. I'm clueless about steels, but this is educational:)
 
No worries, JDK1, I can talk steel forever. One thing is for sure, SK5 is not the Hitachi White steel! And remember, you can have the BEST steel in the world, it is useless without a good heat treat.
 
samuraistuart said:
No worries, JDK1, I can talk steel forever. One thing is for sure, SK5 is not the Hitachi White steel! And remember, you can have the BEST steel in the world, it is useless without a good heat treat.
Click to expand...
Absolutely! Some folks couldn't make an edible meal with a $1000 Whole Foods gift card while others can dazzle you with whatever's in the pantry:D
 
This may not be completely on topic, but my Spyderco Stretch in Super blue gets crazy sharp really easy and keeps that edge for a long time. However, that edge can chip extremely easily doing daily tasks. Not sure if others have experienced this or not, but I have two rather large chips on it right now. I still love that knife, but the edge durability is a worry for me. I have no experience with the white steels.
 
You must log in or register to reply here.
Back
Top