Hitachi Steel Heat Treatment

samuraistuart

samuraistuart

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Dec 21, 2006
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Since Hitachi White and Blue steel are available from a couple of different online vendors, Dictum and Workshopheaven, I thought about starting a thread that talked about these steels, particularly the heat treat requirements they need. Super Blue isn't available to us yet, AFAIK. Wish it was! I did a few quick searches to locate heat treat data on Shiro (white) and Ao (blue)...but about all I can find is the PDF file that has a couple of charts for hardening and tempering the two different steels, and the austenitizing temps have a wide margin. I don't think there are any real special requirements to consider when heat treating white or blue steels, but if anyone has experience with either, I would love your input.

White steel is much like 1095, just carbon, manganese, and some silicon. Blue steel is much like O7, with vanadium and tungsten. White steel being a super fine grained steel, and blue steel being not quite as fine grained but has the vanadium and tungsten carbides. White steel can take a super sharp edge....but loses that edge faster than blue. Blue steel can't take quite as fine an edge, and that edge lasts longer than White steel. When I say "not quite as sharp", or "doesn't last as long", this is relative to each other, not meaning to compare to other steels. I think we all know the Hitachi steels are super performers.

White steel can be quenched in water or oil, whereas the blue steel must be oil quenched. I don't know much more about Hitachi steels, other than their impurity level is very low. The sulfur and phosphorous levels are lower than most any other steel out there. Not sure what that translates to in real world use, tho.

If I was heat treating White steel, I would treat it like I would 1095, with an austenitizing temp of 1475F with a 10-15 minute soak. Tempering temp of 400F should get 61 hrc. However, with Blue steel, I'm curious as to other peoples thoughts on what temp they would pick for hardening. If no normalizing/grain refining was done....I might be inclined to go with 1530F. But if normalizing was done...I might stay with 1475F and treat it like I would White steel.

Would you care to add? Thanks so much

Stu
 
I just did a small fighter in Hitachi White, and is Rc 63 right now, with a 375f temper (I was tempering some 15N20 at the same time.) I used 1450 to austentize, 15 min soak, no clay, quenched in DT48, and there is a distinct hamon visible at the 220g sanding already. I am going to temper it to Rc61/62, as it is my personal knife and won't be used hard. If its chippy (I doubt it will be, I'll temper it back.) I have the blue steel laminate, and planned to austentize at 1485. The heat treat info that comes with the steel lists 1400f to 1525 as the heat treat range for white, and 1435 to 1525 for the blue steels.
 
I got my information from the second link Stacy posted (it came with the steel), and used a conversion calculator to get the imperial temps.
 
Here's some note about Hitach PDF.
白紙 for White steel. there are four types of White steel, namely first, second, third and sawblade. Listed in this order in the table of page four.
青紙 for Blue steel which also has three kinds as first, second and super. super blue has vanadium of 0.3-0.5 percent.

Along with these carbon steels and low alloy steels, five stainless steels are also documented as Gin-1, Gin-2, Gin-3, ATS34 and ZDP.
The second page shows quench charts where you can find the chart for White-2 in the middle of top row and Blue-1 on the left of the middle row.
 
fujita yuji said:
Here's some note about Hitach PDF.
白紙 for White steel. there are four types of White steel, namely first, second, third and sawblade. Listed in this order in the table of page four.
青紙 for Blue steel which also has three kinds as first, second and super. super blue has vanadium of 0.3-0.5 percent.

Along with these carbon steels and low alloy steels, five stainless steels are also documented as Gin-1, Gin-2, Gin-3, ATS34 and ZDP.
The second page shows quench charts where you can find the chart for White-2 in the middle of top row and Blue-1 on the left of the middle row.
Click to expand...

Thanks for all the input here fellas. This (above) is great info too. I meant to include in the post the various White steels and various Blue steels. The carbon content varying between White 1, White 2, White 3 (White 1 having more carbon than White 2, 2 having more than 3....and the same with Blue steel, 1,2,3). Then, I think there is even further distinction (not too sure here) with a letter after the number, as in White 1a, White 2a, etc.

Can anyone help translate the first link Stacy supplied us with? I tried google translate....I tried saving the pdf file and translating directly...I can't seem to get it to work for me, and I'm really interested in checking it out.
 
Most of the charts and such are easy enough to figure out. The info is available in English. I will try and find my English copy..
 
samuraistuart said:
Then, I think there is even further distinction (not too sure here) with a letter after the number, as in White 1a, White 2a, etc.
Click to expand...

You mean the letter 号 witten after the digit? If so, it has no particular meaning like you mentioned.
Its a kind of suffix or some sort to generate "proper name" from a numeral.

I pretty much dont understand why Hitachi people do not provide english catalog of their cutlery steels.
If they think their steel is good for Japanese smiths, it can be a good choice for the smiths of other countries.
Chemistry and physics works the same regardless of the countries.
 
We would love to have their info in English, as well as use their steel.

Sadly, Hitachi will not sell its steel to the US market, which is a large part of the English speaking knifemaker world. I have never heard a good explanation of why they won't. but it is clearly true. Even the two European companies that sell Hitachi steel have a limited selection, and have to sell it under the guise of being a tool company.

I and others have tried to purchase it directly from Hitachi America with no success, and when we tried to go directly to Hitachi in Japan, they said they wouldn't sell it in small amounts...so we tried to make a purchase order for larger and larger quantities of Hitachi aogami and shirogami. They play around and then say, "No, sorry, we will not sell it to you." We are talking about thousands of pounds as of the last attempt. I only know of one US maker who can get it shipped to him, because he had a relationship with the knife industry and Hitachi when he was in Japan.

I have been told that the reasoning was to protect the Japanese knife industry from being wiped out by US and European competition. As it stands right now, if you want a quality steel Japanese style blade, you have to get it from a Japanese company or maker. There are a few small and limited exceptions, but basically, Japan gets the lion's share of the income from knives made in Hitachi steel. It may be sold by a big US or EU company, but the blade was most likely made in Japan.
 
Sucks for us... but I say good for them! They are keeping their "edge" on the market. It is not like they are holding back any world-changing technology like cold fusion or the herpes vaccine. It makes those lucky few who have access to blue and white even more special-er. I would like to get my hands on a piece but would most likely not give it its just treatment. Why can't NA companies produce Hitachi grade steel?(serious question)
 
They probably could, but would need to be convinced that there would be enough demand to do so. Cutlery steel is a tiny sector of the steel industry, so producing something special for it and copying something that is already in the market might be a hard sell to the management of the companies. So it is more a question of why don't they, not why couldn't they.
 
To be honest I've never seen these cutlery steels in tool steel store doing business with industries like mold, die, cutting and so on.
White and Blue steels are distributed in totally different way compared to other tool steels like HSS, D2 or O1 here in Japan.
For example I can buy HSS stock from those tool steel stores but not these cutlery steels discussed here.
They are distributed exclusively to the domestic cutlery industries. The only exception is a knife store which also sells knife making kits and materials.
In this case they are priced very high.

They simply do not have a distribution channel for other countries. I dont know the reason. Maybe domestic industry protection as Stacy said, or
maybe just because of convention and Hitachi people fails to recognize their business chance.
Hitachi is a Huge and conservative company and infamous for ignoring new business.

But things are changing gradually. For example http://www.yamamura-mfg.co.jp/g-material.html this company says
they can sell White, Blue and other cutlery steels to consumers (which includes hobby knife making person like me).
Maybe you can make a contact to them if you're interested.
 
Note that on the German site they mention that dry sharpening or a belt sander is damaging to the crystal structure !! Use water cooled machine or hand sharpen on Japanese water stones.
I agree with that !!!

Hitachi --- A company stuck in the old ways can distroy itself .Exactly what happened to KODAK and they were the ones who developed the digital camera then ignored it !
 
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In my opinion everyone wants the paper steels because they cant have them. The allure and mystique of the unobtainable is much more powerful than difference from that steel or other steels with similar chemistry.
 
"Can't have them?" That sure isn't why I am interested in them.....because they CAN be had. As far as the letter after the name and number, as in White 1, White 1a, White 1b, White 2, White 2a....from what I gather the carbon content decreases just a tad. As in White 1 has just a touch more than White 1a, which has a touch more than White 1b. Same with Aogami as well (blue steel). I've never come across these sub-distinctions in the real world, just noticed on Zknives comparison chart....they're listed.
 
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