Japanese Steels

What is the deal with Japanese steels? I believe that Japanese "White" and "Blue" steels are highly desierable for knives and woodworking tools and Maestro Livi uses AS Steel (which I believe is a form of Blue Steel) from Shosui Takeda for some of his razors.

How do these steels compare to western steels, eg. hardness, edge retention, durability and performance? Looking for more knife/razor preformance rather then for a chisel. Any one with a Livi-Takeda feel free to chime in.

Also in a previous thread O-1 was stated to be the preferred steel to use, why not A-2, D-2, S-7 or 5160?

~john

Japanese steels are graded green, yellow, white and blue and usually three levels (1, 2, 3 best to less best) within those colors. The best steel for edges is Blue No.1 Supersteel. That's what's found in the best kitchen knives at the edge. It's a combination of iron carbon chromium molybdenum vanadium and tungsten. The Japanese have done some of the best work with modern alloying materials, although you will find some German steels at that same level. Who copies whom? Dunno. But for comparison, they hold a very fine edge despite being brittle.

S7 and 5160 will not have the highest edge retention (staying sharp the longest) but they will likely survive a drop off the counter to the floor. D2 and A2 are air hardening steels and can be brittle at razor hardnesses. Both make very fine cutting edges if heat treated correctly.

For a steel with no temperamental heat treatment issues and a good range of performance a 10xx steel with at least 0.8% carbon or greater or good old O-1, W-1 are just fine. Simple, but fine.

The more complex things get, the more problems occur unless everything is controlled just right.

just my 2 cents. S7 is a shock resistant steel. It's used in some hammers and a lot of bladesmith's use it to forge tomahawks with. Either in round bar or by finding hammer heads made of it and chopping off the handle and forging it into a tomahawk. 5160 is a spring steel. If you have a place that makes springs nearby for automobiles you can buy alot of it from them cheap to practice on. Makes great bowies and big choppers. I can't help you with A2. D2 is a good steel, Dozer uses it alot on his knives. I have one and have never had a problem with it. Takes a lot of abuse to dull it. It's a great little knife.