# Blue Steel #2 vs White Steel #2



## bechler (Mar 14, 2012)

I searched the forum and couldn't find a head to head comparison. I am sure it is out there an apologize if I overlooked a thread but can someone give me a quick rundown on which steel is better?


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## GlassEye (Mar 14, 2012)

One is not better than the other, really. They are just slightly different. 
Check out zknives.com for comparing any steel you may want to.


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## JBroida (Mar 14, 2012)

better is not very easy to say... they are different for sure. Here's a brief rundown on steels made by hitachi-

The most basic and cheap steels made by hitachi are the sk steels (sk3, sk4, sk5). These are pretty simple carbon steels that arent particularly pure (sulfur and phosphorus). When you increase the purity a bit, you get yellow steel (yellow 3, yellow 2). These are more pure than the sk steels, but still not super pure. The lower the number, the more carbon the steel has (i.e. sk3 has more carbon than sk4, and yellow 2 has more carbon than yellow 3). When you increase the purity of yellow steel, you get white steel. (white 3, white 2, and white 1). White steel is a simple, pure carbon steel that takes a great edge, sharpens easily, and has good toughness. From white steel, when you add a bit of chromium and tungsten, you get blue steel (i.e. white #2 plus a bit of chromium and tungsten yields blue #2... the carbon level is equal). Blue steel has better edge retention and corrosion resistance than white steel at the cost of not getting quite as sharp, being a bit more difficult to sharpen, and being a bit more brittle. Blue #1 would be white #1 with chromium and tungsten added. Blue super is created by taking blue #1 and adding even more carbon, chromium, and tungsten. It has the best edge retention and corrosion resistance at the cost of being more brittle and tougher to sharpen. So if you wanted to make a scale with the white and blue steels most often used in kitchen knives, with one side being the easiest to sharpen and having the best toughness and the other side having the best edge retention and corrosion resistance (but being a bit more brittle), on the first end you would have white #2 (or white #3, but #2 is more common) and on the other side, blue super.

Does that make sense?


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## tk59 (Mar 14, 2012)

Keep in mind that while blue steel is more corrosion resistant, that is really a pretty minor effect, in my experience. There is very little chromium in any of them and some (or nearly all) of it is probably tied up in carbides. I would also say that in the grand scheme of things, they are all terribly easy to sharpen when done right. In my mind, it's really an ultimate sharpness vs wear resistance trade-off.


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## sel1k1 (Mar 14, 2012)

Great thread.:thumbsup:


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## JBroida (Mar 14, 2012)

and heat treatments can vary and make a big difference


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## 99Limited (Mar 14, 2012)

JBroida said:


> and heat treatments can vary and make a big difference



This should be written in big, bold letters any time steel comparisons are brought up.


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## echerub (Mar 14, 2012)

It makes a very dramatic difference.


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## Seth (Mar 14, 2012)

I asked this once before but didn't really get my question across -- so, if you have blue 2 that is low temperature forged are you moving toward the best of both worlds?


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## JBroida (Mar 15, 2012)

not necessairly


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## Justin0505 (Mar 15, 2012)

JBroida said:


> better is not very easy to say... they are different for sure. Here's a brief rundown on steels made by hitachi-
> 
> The most basic and cheap steels made by hitachi are the sk steels (sk3, sk4, sk5). These are pretty simple carbon steels that arent particularly pure (sulfur and phosphorus). When you increase the purity a bit, you get yellow steel (yellow 3, yellow 2). These are more pure than the sk steels, but still not super pure. The lower the number, the more carbon the steel has (i.e. sk3 has more carbon than sk4, and yellow 2 has more carbon than yellow 3). When you increase the purity of yellow steel, you get white steel. (white 3, white 2, and white 1). White steel is a simple, pure carbon steel that takes a great edge, sharpens easily, and has good toughness. From white steel, when you add a bit of chromium and tungsten, you get blue steel (i.e. white #2 plus a bit of chromium and tungsten yields blue #2... the carbon level is equal). Blue steel has better edge retention and corrosion resistance than white steel at the cost of not getting quite as sharp, being a bit more difficult to sharpen, and being a bit more brittle. Blue #1 would be white #1 with chromium and tungsten added. Blue super is created by taking blue #1 and adding even more carbon, chromium, and tungsten. It has the best edge retention and corrosion resistance at the cost of being more brittle and tougher to sharpen. So if you wanted to make a scale with the white and blue steels most often used in kitchen knives, with one side being the easiest to sharpen and having the best toughness and the other side having the best edge retention and corrosion resistance (but being a bit more brittle), on the first end you would have white #2 (or white #3, but #2 is more common) and on the other side, blue super.
> 
> Does that make sense?



That's the clearest, most concise summary of the hitachi rainbow that I've ever read. It took me a loooong time to piece the same information together on my own. I'm sure that's a spcheal that you give daily in you store, but it's great to have it hear for all to see.


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## Sarge (Mar 15, 2012)

I believe it is also posted on his website at JKI. Is there a reason beyond brittleness that we don't see AS used in traditional single bevel blades or is it due to smiths being more familiar with and therefore better and more consistent with White and Blue 1&2.


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## JBroida (Mar 15, 2012)

no... its just not the right steel for single bevel knives due to its inherent properties... there are some makers who do it, but its generally considered to be a joke and only for export


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## Sarge (Mar 15, 2012)

I see said the blind man.


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## EdipisReks (Mar 15, 2012)

Sarge said:


> I see said the blind man.



have you used single bevel knives and AS knives? it makes perfect sense if you have both...


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## Sarge (Mar 15, 2012)

Perhaps to some it does? I used to own a moritaka in AS, my Kiritsuke is in Ginsanko. Perhaps that is why I didn't readily see reasons outside the natural drawbacks of AS, and I should have done a better job of listing those natural drawbacks further than Brittleness. I am not much of a metallurgist; however I do know that yellow steel isn't all that great for single bevels but I've seen it used far more frequently than AS.


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## EdipisReks (Mar 15, 2012)

the AS knives i've owned (a pair of Takedas) and have used (a Moritaka) have crumbled under use at the kind of edge thickness i have with my shirogami usuba. it probably wouldn't crumble that way in a yanagi, as yanagis are thicker, but it would be a pain to remove the kind of material you need to to keep the blade road flat, with the tougher steel.


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## quantumcloud509 (Mar 16, 2012)

JBroida said:


> better is not very easy to say... they are different for sure. Here's a brief rundown on steels made by hitachi-
> 
> The most basic and cheap steels made by hitachi are the sk steels (sk3, sk4, sk5). These are pretty simple carbon steels that arent particularly pure (sulfur and phosphorus). When you increase the purity a bit, you get yellow steel (yellow 3, yellow 2). These are more pure than the sk steels, but still not super pure. The lower the number, the more carbon the steel has (i.e. sk3 has more carbon than sk4, and yellow 2 has more carbon than yellow 3). When you increase the purity of yellow steel, you get white steel. (white 3, white 2, and white 1). White steel is a simple, pure carbon steel that takes a great edge, sharpens easily, and has good toughness. From white steel, when you add a bit of chromium and tungsten, you get blue steel (i.e. white #2 plus a bit of chromium and tungsten yields blue #2... the carbon level is equal). Blue steel has better edge retention and corrosion resistance than white steel at the cost of not getting quite as sharp, being a bit more difficult to sharpen, and being a bit more brittle. Blue #1 would be white #1 with chromium and tungsten added. Blue super is created by taking blue #1 and adding even more carbon, chromium, and tungsten. It has the best edge retention and corrosion resistance at the cost of being more brittle and tougher to sharpen. So if you wanted to make a scale with the white and blue steels most often used in kitchen knives, with one side being the easiest to sharpen and having the best toughness and the other side having the best edge retention and corrosion resistance (but being a bit more brittle), on the first end you would have white #2 (or white #3, but #2 is more common) and on the other side, blue super.
> 
> Does that make sense?



Wow man, thank you so much! That was very clear to understand. 4x Takedas in hand. Love the blue #2.


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## Timthebeaver (Mar 16, 2012)

Takeda does make knives in other blue steels, but his AS knives are far more popular/common. Takeda stamps AS or the number of the steel used on the blade.


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## JBroida (Mar 16, 2012)

Sarge said:


> Perhaps to some it does? I used to own a moritaka in AS, my Kiritsuke is in Ginsanko. Perhaps that is why I didn't readily see reasons outside the natural drawbacks of AS, and I should have done a better job of listing those natural drawbacks further than Brittleness. I am not much of a metallurgist; however I do know that yellow steel isn't all that great for single bevels but I've seen it used far more frequently than AS.



yellow steel and white #3 are often misunderstood in the western markets... there are kitchen applications they work well for when done with a skillful hand. For example, white #3 honyaki gyuto is a smart idea... it can be a nice balance of toughness to edge retention and ease of sharpening... much more user friendly than say a white #1 mizuhonyaki wa-gyuto that many people seem to think is a great idea (i probably get this kind of request at least once a week). I think there is a tendency in the western markets to want the max. of everything- i.e. max hardness, max edge retention, max toughness, max amount of carbon, and so one. However, a much more useful and effective approach is understanding the strengths and weakness of different materials and matching those properties to the task at hand. This, however, also requires a deep understanding of the tasks, and is often an area where mistakes are made. Not to go on a complete rant here, but lets take a look at yanagiba for example. There is a group of people who want to take their yanagiba to the highest grit and highest polish that can possible be achieved. What is clear to me is that they have not yet mastered the use of a yanagiba (nor do i claim to have, but i do feel like i have a very solid understanding at this point). The edge of a yanagiba needs to be sharp, but with some bite. Not enough to cause damage to the item being cut, but enough to keep the user connected to the cut (avoiding the feeling of the knife just falling through food with no feeling or so quick you cant tell whats going on).

/rant


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## dragonlord (Mar 16, 2012)

Can we get these 2 posts added to the knowledge repository please.


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## FinkPloyd (Mar 16, 2012)

JBroida said:


> better is not very easy to say... they are different for sure. Here's a brief rundown on steels made by hitachi-
> 
> The most basic and cheap steels made by hitachi are the sk steels (sk3, sk4, sk5). These are pretty simple carbon steels that arent particularly pure (sulfur and phosphorus). When you increase the purity a bit, you get yellow steel (yellow 3, yellow 2). These are more pure than the sk steels, but still not super pure. The lower the number, the more carbon the steel has (i.e. sk3 has more carbon than sk4, and yellow 2 has more carbon than yellow 3). When you increase the purity of yellow steel, you get white steel. (white 3, white 2, and white 1). White steel is a simple, pure carbon steel that takes a great edge, sharpens easily, and has good toughness. From white steel, when you add a bit of chromium and tungsten, you get blue steel (i.e. white #2 plus a bit of chromium and tungsten yields blue #2... the carbon level is equal). Blue steel has better edge retention and corrosion resistance than white steel at the cost of not getting quite as sharp, being a bit more difficult to sharpen, and being a bit more brittle. Blue #1 would be white #1 with chromium and tungsten added. Blue super is created by taking blue #1 and adding even more carbon, chromium, and tungsten. It has the best edge retention and corrosion resistance at the cost of being more brittle and tougher to sharpen. So if you wanted to make a scale with the white and blue steels most often used in kitchen knives, with one side being the easiest to sharpen and having the best toughness and the other side having the best edge retention and corrosion resistance (but being a bit more brittle), on the first end you would have white #2 (or white #3, but #2 is more common) and on the other side, blue super.
> 
> Does that make sense?



Jon, you made my day.

No one here (anywhere) took the time to expose years of experience in one simple-to-understand paragraph. I sincerely thank you for that.

I met you in person when I purchased a diamond flattening plate not long ago. You are a humble person, and what impressed me is your willingness to openly share your rich experience. I don't see many knife retailers being this passionate about their blades as you are. Your Tamashii is intact because you believe.

I salute you my friend!


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## Sarge (Mar 16, 2012)

JBroida said:


> yellow steel and white #3 are often misunderstood in the western markets... there are kitchen applications they work well for when done with a skillful hand. For example, white #3 honyaki gyuto is a smart idea... it can be a nice balance of toughness to edge retention and ease of sharpening... much more user friendly than say a white #1 mizuhonyaki wa-gyuto that many people seem to think is a great idea (i probably get this kind of request at least once a week). I think there is a tendency in the western markets to want the max. of everything- i.e. max hardness, max edge retention, max toughness, max amount of carbon, and so one. However, a much more useful and effective approach is understanding the strengths and weakness of different materials and matching those properties to the task at hand. This, however, also requires a deep understanding of the tasks, and is often an area where mistakes are made. Not to go on a complete rant here, but lets take a look at yanagiba for example. There is a group of people who want to take their yanagiba to the highest grit and highest polish that can possible be achieved. What is clear to me is that they have not yet mastered the use of a yanagiba (nor do i claim to have, but i do feel like i have a very solid understanding at this point). The edge of a yanagiba needs to be sharp, but with some bite. Not enough to cause damage to the item being cut, but enough to keep the user connected to the cut (avoiding the feeling of the knife just falling through food with no feeling or so quick you cant tell whats going on).
> 
> /rant



Thank you for the excellent answer. The concept of putting the edge you want for the tasks you need is something I really started to learn from you as you demoed and explained your choices with the Gesshin stones. It has certainly helped to improve my cutting. I am starting to also pursue more the idea of balance and choosing what you need from the steel for the tasks at hand. Wonderful explanations as usual.


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## mpukas (Mar 16, 2012)

JBroida said:


> its generally considered to be a joke and only for export



Thanks once again for the excellent and insigtful commetns/answers, Jon. Can you say a little more about why Japanese makers/chefs don't like AS? mpp


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## JBroida (Mar 16, 2012)

mpukas said:


> Thanks once again for the excellent and insigtful commetns/answers, Jon. Can you say a little more about why Japanese makers/chefs don't like AS? mpp



its not that they dont like AS... its just that they like AS for what it is good for.


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