White and Blue: Japanese Steel

[Jim Wilson]

I recently obtained some additional details on these steel products from the manufacturer, Hitachi Metals. I inquired, hoping to purchase some for making tools. Shinichiro Kitagawa of the San Jose office was kind enough to provide me with a quote for the grades in which I am interested. Unfortunately, the minimum order quantity for shipment to the US is 500 lbs per grade, so I won't be able to make a purchase right away...

By the way, my receiving a quote for these materials refutes the occasionally stated claim that certain grades of these products are sold only to toolmakers who meet specific skill requirements imposed by Hitachi. The only thing Hitachi required of me to become a customer was good credit.

Here's the scoop:

The facilities at Hitachi's Yasugi Works produce a number of steel and other metal products. They are sometimes identified as "Yasuki" (because they're made at the Yasugi plant) or "YSS". The steel stock used by Japanese woodworking edge tool makers is called "YSS High Class Cutlery" steel and is wrapped in paper or labeled by the manufacturer. The color of the paper or label indicates the type of steel.

I think there may be a play on words in the names, as "gami" means "high class," but "xx-gami" usually refers to a type of paper ("xx-" being the type). For examples, "atsugami" is cardboard or thick paper, "hanagami" is tissue paper, "gingami" is silver paper, and so on. However, I don't speak Japanese, and would appreciate input on this from anyone who does. Incidentally, I also have a brochure for these steels in Japanese (it's not available in English). If anyone can help translate it for me, I would be indebted.

White steel is a common shorthand name for white paper steel ("shirogami hagane") which can be any of several fairly simple high carbon, water hardening steel grades. The carbon content varies by grade, and runs from

0.8 to 1.4%. The range of carbon content within a grade is a tight 0.1%. For example, the carbon content of Shirogami Hagani No1A is specified to be between 1.3 and 1.4%. Each grade also contains 0.1-0.2% silicon and 0.2-0.3% manganese, and only trace amounts of the impurities sulfur and phosphorus.

Blue paper steel ("aogami hagane") is also offered in several grades, with carbon content ranging similarly to the "white" grades. However, blue steel contains the additional alloying elements chromium and tungsten, and one grade ("aogami super") also contains molybdenum and vanadium. The blue steels can be quenched in water or oil, whereas most of the white grades need a faster quench and require water.

A list of the YSS high-class cutlery steel grades and the specifications for their composition, heat treatment and hardness is available on my web site:

to Hitachi Metals, Ltd, for the information.

Jim

[bridger]

just a thought.

I wonder if the wreck could pool enough customers to meet hitachi's minimum order....

[Jim Wilson]

I don't know. 500 lbs would be enough to make more than 9,500 laminated plane irons, or about 15,000 chisels. (Assuming the bulk of the tool is a soft steel.) Seems like a lot for a niche market.

Jim

[Steve Knight]

about a year and a half for me (G) well I use about 90 to 100# every three months approx. how much is the good white steel a pound?

[Jim Wilson]

That's for solid irons, though, right? If your irons are like mine, 1/4" thick x 2" x 4", you get about 175 irons per hundred pounds of steel. That sound about right?

If the Hitachi steel were to be used on laminated irons, you'd only need about a 55mm square x 1mm thick. The rest of the tool would be plain steel. So, you could theoretically get over 2200 irons per hundred pounds of the tool steel. Because of the stock dimensions, though, there'd be a bit of waste, which would drop the yield to probably just under 2000 irons per hundred pounds.

It's all good, right? (G) Hitachi quoted me $9.06 / lb for the No1A white paper steel, in 500 lb quantities, cold-rolled. The Aogami No2 was $10.46. I pay about half that for precision ground O1.

Cheers!

Jim

[Alan W]

It would be my understanding, that extensive further manipulation of this steel would be necessary to forgeweld the plain steel onto the white or blue steel, and that this process is, in addition to the hard steel, is the real value in japanese high end tools.

Although tempting, a solid blue or white steel tool would be quite brittle according to common espoused literature, and the job of the soft steel is to provide shock resistance and support for the super hard layer.

Alan

[CW]

It would make a fine tool. The brittleness is controlled by the tempering.

[Jim Wilson]

Absolutely true, of course. Quality tools don't make themselves! (G) The smith definitely earns his credit.

It would be a waste, given the high relative cost of the material. However, it is almost certainly possible, technically, to make a fine blade from solid white or blue steel, if by no other means than differential heat treatment. That doesn't necessarily make it a good idea, though. The laminated design has real merits that can't be duplicated well by other means.

Jim

[Jim Wilson]

I agree that it could.

It can be to a large extent. In steel, the trade-off for decreasing the brittleness by tempering is often lost wear resistance, and consequently, edge retention. The optimal balance point for this trade-off depends on the chemistry of the alloy as well as the application.

The extremely high carbon content of these steels and the lack of toughening alloying elements to "glue" the hard micro-particles together suggests that a solid tool might need to be tempered quite hot to reach an acceptable level of toughness. That could have an excessively adverse affect on edge retention, unless the very edge were tempered to a lesser degree. (G)

A comparison between the No1A white steel and white cast iron is interesting:

Alloying Element No1A white steel white cast iron ============ ================== ================= Carbon 1.3-1.4% 1.8-3.6% Silicon 0.1-0.2 0.5-1.9 Manganese 0.2-0.3 0.25-0.8 Phosphorus

[Steve Knight]

I make them 5" or so long 6 irons per 36" bar. about 120 or so.

a bit spendy then. but nice to think about (G) I don't think the steel would be as good in solid form over a laminated blade.

[JD]

Kami means paper (also hair, god ...) Each is a different kanji (or character) When a word that begins with a ka is incorporated into another word the ka is frequently changed to a ga. I may be wrong, but it doesn't appear that there is any play on words going on here.

Here is the rest of the vocabulary that you have used. Atsui means thick Hana likely means nose in this case, but could mean flower. Gin is Silver. Ao is blue Shiro is white

-Jack

[Jim Wilson]

Thanks, Jack. The play on words I was guessing at was calling the steel "High Class," and identifying it by it's wrapper color. Gami Hagane, Shirogami Hagane, etc. But I don't know how it would look in Japanese.

Thanks again,

Jim

[Jim Wilson]

Yabbut under 50 cents in tool steel in each laminated iron.

Oh, yes!

Have to agree with that, especially now that the chemical composition is known. It sure would be great to give this stuff a shot.

Cheers!

Jim

[Andy Dingley]

All Japanese etymology is a play on words. Every character has a shedload of meanings. Every word is only a couple of characters. There's huge duplication and potential ambiguity here.

The creation of a "beautiful" word (which is the wrong term, but there is an aesthetic notion here) is in picking something that has several meanings, made by reading the same characters in different ways and having many or all of the meanings relevant to the concept expressed by the overall word.

[Jim Wilson]

That was my guarded suspicion, but being completely ignorant of Japanese, I have no way of knowing at this point. Do you know whether the characters for "High Class Cutlery" and "White Paper Steel" (for example) bear any semblence to each other? Or, is it just a coincidence that the phonetic translations jive in English?

Jim

P.S. I confess that I was hoping you would comment on the conjectures in my response to CW's post yesterday, Andy. I thought you might have some insight into the chemistry/performance relationship of these products that you could share.

Cheers!

Jim

[Jack]

Yes, but the character for Kami (paper) is completely different from either of the characters in the word gami. Really all they share is that they sound alike. Jim Breen has an excellent site which deals with Japanese translations and characters.

The creation of a "beautiful" word (which is the wrong term, but there

I'd agree, but none of that is going on here. Both of these gami's are as alike as toy is to toilet or toyota. Ok, I take that back. They are the gami's are even less alike...

-Jack

[Steve Knight]

and 80.00 labor (G)

[Jim Wilson]

Exactly! For 2000 irons! With a glut like that, you might be able to sell 'em for twenty bucks apiece! (G)

Jim

[Jim Wilson]

Jim

[Steve Knight]

just getting the blades I have made now are a battle. they keep costing more and I still have to have them surface ground. I would not like all my planes to have laminated blades (G) though I wish I could get them all with laminated blades and chuck the solid O-1.