Steel Type Guide

Learn more about our steels.

Shall I compare thee to a carbon steel?

Thou art more lovely and more rust-resistant. Kitchen knives are made from a variety of steels, from stainless to high carbon and everything in between. Each steel type comes with its own attributes, strengths and weaknesses. 

There is a lot to learn when it comes to steels—it can be pretty overwhelming. That is why we have put together this guide to break down the different steel types in a clear, easy-to-understand way. 

Steel Categories

Terms to Understand

Hardness

The degree of hardness of steel largely depends on the amount of carbon it contains; the higher the carbon content, the harder the steel is.

The Hardness Rockwell C scale, or HRC scale, is widely used when measuring hardness. The majority of kitchen knives will measure from 52 to 68 HRC, with Japanese steels usually situated at the upper end between 58–68 HRC.

Durability

The ability to withstand damage from bending, twisting or cutting is referred to as durability, with softer steels displaying greater flexibility while harder steels are more prone to brittleness.

Durable steels may not be as sharp as harder materials, however, they are ideal for demanding tasks. When cutting tough materials such as winter squash, cheese and bone, using a highly durable knife is recommended to minimize the risk of chipping.

Steel Type Category

High Carbon

What is High Carbon Steel?

High Carbon Steel is an alloy composed of iron and carbon, with a Carbon content around 2.0%. Unlike Stainless Steel, it lacks elements that inhibit corrosion – leading to a higher risk of discoloration and rusting. High Carbon Steel boasts an impressive history in Japan, its ability to offer optimized edge sharpness, retention and ease of sharpening make it the ideal steel for adept and experienced users. Carbon Steel requires extra maintenance but is greatly appreciated for its inherent advantages and preference.

Renowned for their superior sharpness, edge retention and ease of sharpening these knives require extra care since they are prone to damage and rusting.

High Carbon Steel Types

Blue Steel No.1, an iteration of aogami ("blue paper" steel), boasts superior edge sharpness when compared to other variations of blue steel. This type of steel, very similar to shiogami 1 ("white paper" steel), is slightly more durable due to the added tungsten. Blue 1 is frequently used to forge high quality Japanese kitchen knives.

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Category: High Carbon Steel

HRC: 65+

Blue steel, referred to as Aogami ('Blue Paper' steel) is comparable to its White Steel or Shiogami ('White Paper' steel) counterpart with the addition of Chrome and Tungsten. Blue No.2 stands out due to its impressive edge retention and hardness.

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Category: High Carbon Steel

HRC: 61-63

Blue Super is a form of blue steel, often referred to as aogami ("blue paper" steel), that is substantially similar to its sister variety, the white steel (or shiogami, "white paper" steel), to which chrome and tungsten have been added. This steel is further enhanced with the addition of molybdenum and vanadium, resulting in superior edge retention that has made it a popular choice for many craftsmen.

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Category: High Carbon Steel

HRC: 63-64

White Steel, also known as 'Shirogami' (meaning 'white paper') is renowned for its close similarity to traditional steel. Comprising of very few impurities, such as phosphorus and sulfur, White Steel is renowned for its excellent edge retention yet is prone to rusting.

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Category: High Carbon Steel

HRC: 65+

White Steel No.2 is the most popular variant of White Steel, featuring mid-range hardness and providing a great balance of practical qualities. White Steel, also known as 'Shirogami' (meaning 'white paper') is renowned for its close similarity to traditional tatara hand forged steel. As such a pure steel, White Steel is renowned for its excellent edge retention though is prone to rusting and damage.

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Category: High Carbon Steel

HRC: 60-61

Honyaki is a method of creating Japanese blades by using clay to produce differential heat treatment to the same steel. Rather than crafting a blade from layers of both harder and softer steel, Honyaki blades are constructed from the same steel with a hardened edge and unhardened spine. Differential hardening creates internal stresses that increases hardness, creating a blade that holds an edge unrivaled in quality though highly vulnerable to rust.

This technique is exceedingly challenging to execute, with a success rate of about 10%.

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Category: High Carbon Steel

Tamahagane, or “jewel steel”, is a traditional form of steel that has been produced in Japan for centuries and requires an immense amount of time and effort to create. The production process begins with collecting iron from sand, then it is only the hands of master craftsmen that can forge tamahagane into certified samurai swords and kitchen knife blades.

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More Terms

Sharpness

The sharpness of a knife is determined by a few factors, chiefly the hardness of the steel at the blade's core. Harder steels can be sharpened to a finer edge while also retaining said edge better than softer steels, which should be ground at a greater thickness.

It is also important to consider the grain structure of the steel, as a finer grain structure results in a more acute edge. By refining the grains of the steel, it is possible to achieve a sharper cutting edge.

Edge Retention

Edge Retention is a measure of a steel's ability to maintain a sharp edge over time. It is dependent upon the hardness of the steel itself, with harder steels being able to sustain a sharp edge for prolonged periods of time due to their superior hardness in comparison to softer steels.

Japanese steels boast superior edge retention in comparison to other steels, with some varieties being capable of retaining their sharp edge over a period of up to a year prior to needing to be sharpened.

Steel Type Category

Stainless

What are Stainless Steels?

Stainless steels contain properties that allow them to be resistant to staining and rust. Compared to other stainless steels, those made in Japan typically have a higher carbon content. Though this makes them more delicate and less stain resistant, the high carbon content makes Japanese stainless steels sharper and dull less quickly.

Sharp, reliable and built to last, these steels offer an effortless cooking experience with minimal maintenance.

Stainless Steel Types

VG10, also known as V Gold 10, has earned a reputation for being a high-grade stainless steel with excellent cutting properties. Manufactured by Takefu Special Steel Company, VG10 is favored for its balance of hardness and durability, as well as its enduring edges and resistance to chipping in comparison to other Japanese steels.

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Category: Stainless Steel

HRC: 60-61

VG1 is produced by Takefu Special Steel Company and is an amazing steel with much of the same qualities of its successor, VG10. The metallurgic content is a bit different in VG1, making VG10 slightly harder.

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Category: Stainless Steel

HRC: 59-60

AUS10 is a popular, tested and tried stainless steel for kitchen knives produced by Aichi Steel Company. Is a great introductory steel to Japanese knives, as it is easy to sharpen, very durable, rust resistant, and is usually reasonably priced. Compared to AUS8, AUS10 has better performance, edge retention and ability to hold a sharper edge.

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Category: Stainless Steel

HRC: 59-60

AUS8, also referred to as INOX steel, is very similar in composition to AUS10, though doesn't hold as sharp an edge for as long. Produced by Aichi Steel Company, AUS8 is a great introductory steel to Japanese knives, as it is easy to sharpen, very durable, rust resistant, and is usually reasonably priced.

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Category: Stainless Steel

HRC: 58-59

Silver Steel No.3, otherwise known as ginsan, is a stainless steel with a high carbon content and a fine grain structure. This steel has a cutting quality that is comparable to a shirogami (white steel) and the ease of sharpening of a carbon steel.

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Category: Stainless Steel

HRC: 59-61

Chromax is an impressive yet somewhat lesser known steel in the knife industry. It is heat treated to a Rockwell Hardness of 64-65, signifying excellent edge retention capabilities.

Chromax is the designation for stainless clad V-GIN-1 from Takefu special steel. V-GIN-1 Is a semi stainless steel that is more durable than high level carbon steel, with some stain resistance added.

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Category: Semi-Stainless Steel

HRC: 64-65

Sakai Takayuki produces TUS Steel, otherwise known as Takayuki Special Steel, which is a molybdenum-vanadium stainless steel alloy. This unique combination of elements results in a higher degree of sharpness and hardness compared to other cost-efficient alloy variations, although not as much as more expensive alloys.

Although users of TUS Steel may need to sharpen their blades more frequently, they tend to experience less chipping than when using premium alloys.

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Category: Stainless Steel

HRC: 58-59

A Few More Terms

Grain Structure

The grain structure of steel relates to the size and shape of the material's individual metal components. It can range from small and fine to large and coarse, or a combination of both. The finer and more consistent the grain structure, the sharper edge it can hold.

Due to oxidation prevention additives, stainless steel typically has a less refined grain structure compared to powdered or high-carbon steels. Powder steels are distinguished by their particularly fine and evenly distributed grain structure, stemming from their unique production method.

Ease of Sharpening

The hardness and grain structure of a steel determine the ease of sharpening it. Generally, hard steels require more effort and time to sharpen compared to soft steels. Also, steels with a fine grain structure tend to be easier to sharpen than those with a coarse one. Nonetheless, hard steels with a fine grain structure can be simpler to sharpen than soft steels with a coarse grain structure.

Significantly, high carbon steels are quite hard yet they are known for their remarkable ease of sharpening.

Steel Type Category

Powdered Stainless

What are Powdered Stainless Steels?

Powdered Steels are high alloy, stainless steels that have been ground into a highly-refined powder form and then sintered back together. This specialized process creates a more uniform grain structure in the steel, resulting in a product that exhibits exceptional edge retention and hardness.

These steels provide the combined benefit of rust-resistance and exceptional sharpness, however they require more effort to sharpen than their high carbon equivalents, and are less durable than stainless steels due to their hardness.

Powdered Steel Types

Produced by the Takefu Special Steel Company, Cobalt Special Steel is formulated to offer incomparable corrosion resistance due to its 1.1% carbon and 16% chromium content. Tungsten is added to provide greater temper resistance, molybdenum offers superior rust resistance and vanadium creates a finer microstructure. The addition of cobalt increases strength while giving a long-lasting, sharp edge.

Category: Powdered Stainless Steel

HRC: 60-62

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The Hitachi Metal Company produces high-speed steel, HAP40, which is used in larger machining projects due to its superb microstructure and prodigious durability. What makes the alloy special is the presence of different elements like tungsten, molybdenum, vanadium and cobalt as well as 1.27-1.37% carbon and 3.70-4.70% chromium.

Category: Powdered Stainless Steel

HRC: 67-68

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SG2 (R2) is a type of stainless steel with a notably high content of both carbon and alloy. This steel has been refined into a powder form, then sintered to achieve a homogenous grain structure, enhancing the material's sharpening proficiency and resilient properties. Moreover, SG2 stands up remarkably well to corrosion and is ideally suited for use in rapidly paced culinary settings.

Category: Powdered Stainless Steel

HRC: 62-64

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SLD steel provides a dependable sharpness and effectiveness, and is easy to maintain due to its 1.6% carbon and 13.0% chromium content.

SRS13 is a powdered steel containing 1.3% carbon and 13.0% chromium, offering superior edge retention and sharpness, whilst holding onto its stain-resistant properties.

Category: Stainless Powered Steel

HRC: 62-64

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ZA18, developed by Aichi Steel Company, is similar in composition to VG10 and N690, but contains more carbon, chromium, and other elements. This increases its overall strength, durability, and stain-resistance.

Category: Powdered Stainless Steel

HRC: 61-63

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ZDP189, manufactured by Hitachi Metal, is a powdered, stainless steel containing 3.0% carbon and 20.0% chromium with added tungsten and molybdenum. This makes it extremely tough while also giving it some serious wear-resistance. It is difficult to sharpen however, due to the hardness of the material.

Category: Powdered Stainless Steel

HRC: 66-67

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