White#1 vs white#2

[HappyamateurDK]

Hi all.

I've bin of the perception that the difference between white#1 and white#2 was pretty small, almost insignificant.

i have owned some white#2 knives. Nice knives in different price ranges. But I only kept one becouse I thought they where too delicate. Too reactive, and lost sharpness a bit too fast to my taste.

I also have experience with 3 different white#1 knives. A Matsubara, a Hitohira Togashi and a Morihei Hisamoto.

I experience the 2 types of white steel as really different. My white#1's are not very reactive, keeps it's sharpness longer, also longer then some Blue#2 knives i have. It's less chippy. But still easy to sharpen.

Are this a general difference between white#1 and white#2. Or is it all a coincidence caused be different makers different heat treatment?

Have a great day

 

[Se1ryu]

Shirogami no.1 has a higher carbon content so in theory it should be more brittle and reactive than shirogami no.2. especially when compared to Aogami no 2 which is less brittle and reactive than shirogami. It all depends on the knife maker, the heat treatments and the knife owner themselves on how they use and take care of their knife.

 

[Barmoley]

There is nothing in white 1 steel that would make it less reactive than white 2 steel. Their chemical composition differs only in carbon content. Neither steel has any corrosion resistance.

 

[Alder26]

The primary difference (to my knowledge) is that the higher carbon content of white #1 leads to more cementite(?) carbides in the steel which contributes to higher overall hardness. The cementite content also means that white #1 will dull in a more similar way to blue steels where there are other elements added for carbide formation.

 

[Troopah_Knives]

Normally I'm not really part of the HT is everything crowd but Shirgami is the rare exception. The difference between the two steels is very minor. Shiro one will have a bit higher carbide volume assuming a similar HT but with these very low alloy steels, 10˚F or an extra minute of soak time could erase that difference. The only major difference is that it may be possible with HT shooting for lower hardness in Shiro 2 to avoid plate martensite formation (a form of martensite which is much more brittle) and get significantly better hardness toughness balance. However, I have yet to see any evidence that anyone has successfully pulled this off. It is unfortunate that we don't see any work in Shiro 3 which probably has a significantly better balance of hardness to toughness and won't suffer too much in the wear resistance department.

The cementite content also means that white #1 will dull in a more similar way to blue steels where there are other elements added for carbide formation.

This would somewhat depend on the abrasive material you are cutting. If it is silicates that are the most common in food I wouldn't say this is necessarily true as silicates are harder than cementite. While in Aogami the enriched cementite and MC type carbides are harder than that abrasive so the idea that a toothy edge is formed is more plausible.

 

[Alder26]

Normally I'm not really part of the HT is everything crowd but Shirgami is the rare exception. The difference between the two steels is very minor. Shiro one will have a bit higher carbide volume assuming a similar HT but with these very low alloy steels, 10˚F or an extra minute of soak time could erase that difference. The only major difference is that it may be possible with HT shooting for lower hardness in Shiro 2 to avoid plate martensite formation (a form of martensite which is much more brittle) and get significantly better hardness toughness balance. However, I have yet to see any evidence that anyone has successfully pulled this off. It is unfortunate that we don't see any work in Shiro 3 which probably has a significantly better balance of hardness to toughness and won't suffer too much in the wear resistance department.


This would somewhat depend on the abrasive material you are cutting. If it is silicates that are the most common in food I wouldn't say this is necessarily true as silicates are harder than cementite. While in Aogami the enriched cementite and MC type carbides are harder than that abrasive so the idea that a toothy edge is formed is more plausible.

Such an excellent explanation from a top notch knife maker.

In my anecdotal experience I would say that I have seen knives in White #1 hold those toothier biting edges for a longer more often than knives in #2. With that said I have had some exceptional HT of White #2 (think Mazaki, Hinoura, Munetoshi,etc.) perform in very very similar ways. So I suppose that would support your explanation that with such a simple chemical composition there are very few practical differences.

 

[Barmoley]

Such an excellent explanation from a top notch knife maker.

In my anecdotal experience I would say that I have seen knives in White #1 hold those toothier biting edges for a longer more often than knives in #2. With that said I have had some exceptional HT of White #2 (think Mazaki, Hinoura, Munetoshi,etc.) perform in very very similar ways. So I suppose that would support your explanation that with such a simple chemical composition there are very few practical differences.

I think often times white 1 is heat treated harder than white 2 and that is mostly where we see differences in edge holding. Those knives where white 2 is heat treated hard the difference in edge holding between 1 and 2 are less noticeable if at all.

It is unfortunate that we don't see any work in Shiro 3 which probably has a significantly better balance of hardness to toughness and won't suffer too much in the wear resistance department.
.

Funny you should say that. There are reports of people’s experiences with honyaki made out of shiro 3 and they report relatively excellent edge holding that either meets or exceeds shiro 2 honyaki. Of course this is all anecdotal and not very reliable, but there is enough noise about it that there could be something to it.

 

[HappyamateurDK]

Normally I'm not really part of the HT is everything crowd but Shirgami is the rare exception. The difference between the two steels is very minor. Shiro one will have a bit higher carbide volume assuming a similar HT but with these very low alloy steels, 10˚F or an extra minute of soak time could erase that difference. The only major difference is that it may be possible with HT shooting for lower hardness in Shiro 2 to avoid plate martensite formation (a form of martensite which is much more brittle) and get significantly better hardness toughness balance. However, I have yet to see any evidence that anyone has successfully pulled this off. It is unfortunate that we don't see any work in Shiro 3 which probably has a significantly better balance of hardness to toughness and won't suffer too much in the wear resistance department.


This would somewhat depend on the abrasive material you are cutting. If it is silicates that are the most common in food I wouldn't say this is necessarily true as silicates are harder than cementite. While in Aogami the enriched cementite and MC type carbides are harder than that abrasive so the idea that a toothy edge is formed is more plausible.

Thanks for a great explanation
So the short version would be that my experience with the steels could be due to a minor difference in the composition. But are most likely because of different Smith's different way of doing it?

 

[Troopah_Knives]

Thanks for a great explanation
So the short version would be that my experience with the steels could be due to a minor difference in the composition. But are most likely because of different Smith's different way of doing it?

The short version would be that it is likely a difference in geometry as the actual metallurgical differences are very minor and could only be noticed when the geometry is tightly controlled.