Traditional kitchen knives hand-forged by the greatest Japanese masters
Steels
Carbon steel
This steel oxidizes. It has a high carbon percentage, and requires attention and meticulous care. It can be recognized by the high-pitched sound it makes when you stroke the edge with your finger. Knives made with this steel have an unparalleled "razor" cutting edge, and sharpen very easily. Their Rockwell hardness can reach 62-63.
Stainless steel
Steel containing more than 13% chrome is called inox. It is a good compromise: easy to maintain, high-quality cutting, easy to sharpen and strong. Its hardness that can reach HRC 60/61 in the case of certain alloys.
Note that no steel is really stainless. Under extreme conditions, it will end up oxidizing over time.
Powder or sintered steel and HSS
HSS, in other words, high speed steel, is an alloy originally used for high-speed cutting and can withstand high temperatures without losing its temper. Its special feature is the addition of molybdenum or tungsten, which makes it very hard. The principle of sintered steel is to compact ultra fine powder with extremely pure components. Sintered steel can contain up to 3% carbon and 20% chrome, and it is stainless or semi-stainless because the high carbon content makes it more vulnerable to oxidation. Sintered blades have very sharp cutting edges that remain so for a very long time owing to their hardness, which can reach 64-68 HRC.
However, they are more difficult to sharpen and require a good stone.
These alloys are expensive and difficult to forge, which explains the high prices of the finished products.
The main alloys used
CARBON
SHIROGAMI or SHIROKO 1 (white steel)
Hitachi Co., around 1.3% carbon, 0.25% manganese, HRC 61-64.
This is pure carbon steel, fine grained and extremely hard, used by traditional foundries and for forging Honyaki blades.
SHIROGAMI 2
The same components as 1, but in lower quantities.
AOKO or AOGAMI 1 (blue steel)
Hitachi Co., around 1.3% carbon, shirogami base + 1.5% tungsten, 0.4% chromium, HRC 61-64.
The addition of carbides makes it stronger than white steel. It is also used for the best honyaki blades.
AOGAMI 2
The same components as 1, but in lower quantities.
AOGAMI SUPER
Hitachi Co., around 1.4% carbon, aogami base + 0.4% molybdenum, 0.4% vanadium, HRC 61-65.
This high quality steel is even harder and stronger when it is treated well. Able to take very sharp, resistant edges, it cuts beautifully.
V2C
Takefu Co., around 1% carbon, 0.5% chromium, HRC 60- 62.
A simple alloy resembling 52100 or SK3.
TAMAHAGANE
This is relatively soft, high-quality steel that is forged in a blast furnace for long blades, in particular, swords.
STAINLESS
GINSANKO ou SILVER3
Hitachi Co., around 1.05% carbon, 13% chrome, 0.8% manganese, HRC 59-62.
This is the stainless steel traditionally used most often. It is very pure, fine grained and has a good structure for high performance.
VG10
Takefu Co., around 1% carbon, 15% chromium, 1% molybdenum, 0.2% vanadium, 1.4% cobalt, 0.5% manganese, HRC 58-62.
Cutting-edge stainless steel, widely used today for its properties. It can be forged at a higher temperature thanks to the cobalt. It is hard and resistant to wear, strain and oxidation. It will keep a clean, sharpened edge longer. It is also very often used for suminagashi.
VG1 (RC60)
Takefu Co., around 0.95% carbon, 14% chromium and 0.30% molybdenum.
An alloy with a high carbon content that is very resistant owing to the addition of molybdenum.
AUS10
Aichi Co., around 1.05% carbon, 14% chromium, 0.2% molybdenum, 0.2% vanadium, 0.5% manganese, 0.50% nickel, 1% silicon, HRC 58-61.
Middle-range stainless steel with the addition of Mo/V to give it greater strength than basic stainless steel.
UX10
Swedish steel, around 1% carbon, 14% chromium, 1% molybdenum, 0.2% vanadium, HRC 59-61.
Used by Misono for its better range, similar to VG-10, without the addition of cobalt, which makes it less hard than the latter.
MBS26
Masahiro Co., around 0.9% carbon, 14% chromium, 0.1% molybdenum, 0.3% manganese, HRC 58-59.
This is a steel of simple composition, flexible and resistant, providing good results thanks to its high carbon content.
19C27
Swedish steel from Sandvik, with the same characteristics as Ginsanko.
HSS, POWDER STEEL
ZDP189 (MC66)
Hitachi Co., around 3% carbon, 20% chromium, 1.4% molybdenum, 0.1% vanadium, 0.60% tungsten, 0.5% manganese, HRC 64-68.
This is one of the alloys with the greatest amount of carbon. Very hard and resistant: it retains a cutting edge for a long time. This ultra fine powder has exceptional performance, but it is more difficult to sharpen.
COWRY X
Daido Co., 3% carbon, 20% chromium, 1% molybdenum, 0.3% vanadium, HRC 64-67.
Cowry X resembles ZDP-189 but does not contain tungsten.
R2
Kobelco Co. steel, around 1.45% carbon, 16% chromium, 3.2% molybdenum, 2% vanadium and 0.5% manganese, HRC 62-65.
Very resistant to oxidation, wear and strain, this high-quality steel provides optimal results and sharpens relatively easily.
SKD11/ SLD
Hitachi Co., around 1.6% carbon, 13% chromium, 1% molybdenum, 0.4% vanadium, 0.3% manganese, HRC 62-64.
Steel for tools. Well used, it resists wear very well. SLD is the same base, improved at the level of the grain.
SRS15
Around 1.5% carbon, 13% chromium, 2.75% molybdenum, 1.5% vanadium, 1.25% tungsten, HRC 62-64.
An alloy with great resistance to wear. Treated correctly, it performs very well for kitchen knives.
SG2 ou SPG2 (MC63)
Takefu Co., around 1.35% carbon, 14.5% chromium, 2.8% molybdenum, 2% vanadium, 0.35% manganese, 0.10% nickel, HRC 61-63.
Practically the same as R-2.
ATS34
Hitachi Co., around 1.05% carbon, 14% chromium, 4% molybdenum, 0.40% manganese, HRC 61-64.
A very hard, resistant alloy, often used for fixed dagger-type blades.
HAP40
Hitachi Co., around 1.35% carbon, 4.50% chromium, 5% molybdenum, 3% vanadium, 6% tungsten, 8% cobalt, HRC 62-65.With a very hard composition, this alloy gives knife edges an incredible life span.