Steel types

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Common knife steels used in Japan

Carbon steels: 

Carbon steel due to its minimal alloying is dramatically easier to sharpen than stainless and powdered steel cutlery; high levels of Chromium and other carbide forming elements found in stainless steels tend to clog up whetstones quickly during sharpening, sometimes they may require special ceramic stones to cut them efficiently. The fine micro-structure of a properly heat-treated carbon steel knife will be capable of the very highest levels of sharpness whilst maintaining good edge retention, this is generally why top level single sided knives are made predominantly using this steel type. The main trade off is that carbon steel will oxidise, with some being more prone to discolouration than others. 

Tamahagane

Traditional high carbon steel made from iron sand smelted in a purpose built Tatara. This steel is normally reserved for swordmaking but is sometimes found in knives and tools.

Shirogami 1

A very high carbon steel with minimal impurities produced by the Yasuki steel mill.

Shirogami 2

Shirogami 2 has slightly less carbon than Shirogami 1, often this gives it better toughness but this depends on heat treatment.

Aogami 1

The same as Shirogami 1 with added Tungsten and Chromium. This gives it better wear resistance and corrosion resistance.

Aogami 2

The same as Shirogami 2 with added Tungsten and Chromium. This gives it better wear resistance and corrosion resistance. Aogami 2 generally has better toughness than Aogami 1.

Aogami super

The highest carbon tool steel produced by the Yasuki steel mill. This is not only alloyed with Tungsten and Chromium, but also Maganese and Vanadium. This Increases hardness and edge retention dramatically, Aogami super is the most wear resistant traditional carbon steel.

Kigami

A high carbon steel similar to Shirogami but not as pure. Kigami is often found in more budget friendly knives.

SK5

A high carbon steel similar to Shirogami number 2 but also alloyed with Copper, Maganese and Nickel. Also contains more Impurities.

 

Stainless Steels:

The quality of stainless steels used in Japanese cutlery has improved dramatically over the past few years, there are now many high performance stainless steels available with marked improvements in their microstructures and resharpenability. The carbide forming elements used in these steels can often greatly improve edge retention and the high chromium contents makes them highly corrosion resistant. 

VG-10

A high end stainless steel produced by Takefu Special Steels. It's regarded as a super steel and is popular with Japanese knife makers as is capable of high hardness and has good edge retention due to it’s alloying.

VG-1

Slightly less wear resistant but a bit tougher than VG-10.

AUS-10

Produce by the Aichi steel mill. AUS-10 is Similar to VG-10 but less brittle and often a little easier to resharpen.

AUS-8

Slightly less carbon than AUS-10, higher toughness and easier to resharpen.

19C27

A very pure alloy produce by the Sandvik steel mill in Sweeden. Similar to VG-10 but often easier to resharpen, not quite as good wear resistance.

AEB-L

Very pure steel produced by the Udderholm steel mill in Sweeden. AEB-L is renowned for its ability to take a very fine edge.

Ginsanko (silver 3)

A popular high carbon stainless steel produced by the Hitachi steel mill. A well balanced stainless steel that’s reasonably easy to sharpen.

Powdered steel:

Very high carbon tool steels can be put through a special sintering process which drastically refines the micro-structure of the metal increasing toughness, edge retention and hardness potential. These steels have the very best edge retention due to the carbide forming elements used in them, with some being capable of a hardness up to 67 Rockwell! 

ZDP-189

The latest high performance super steel from Hitatchi. This steel has an extremely high carbon content and is very heavily alloyed: simply put this is one of the 2 most advanced knife steels currently used by Japanese smiths.

HAP40

Hitachi’s other commonly used powdered knife steel. Renowned by knife enthusiasts for it’s amazing edge retention.

R2/SG2

A very high performance powdered steel produced by Takefu special steel. Renowned for its edge retention and high hardness.

SLD/SKD11

A semi stainless powdered steel with very high performance.

SRS-15

A high performance powdered steel used by a couple of makers in Japan. Our experience of SRS-15 is that is takes a very good edge considering its composition.