You may jump to specific sections via the table of contents below.
CONTENTS:
Rating of knife steels (properties ranked on a 10-point scale)
5 Key factors that affect knife steels
Individual knife steels - composition & descriptions
Skip to a specific knife steel:
Aogami Super | AUS8 | Blue #1 | Blue #2 | Ginsan | HAP40 | SG2 (R2) | SG STRIX | SKD/Chromax | SRS13 | VG7 | VG10/AUS10 | White #1 | White #2 | White #3
SUMMARY OF TERMS
Rust Resistance
A steel with high rust resistance is less prone to rusting when exposed to moisture, salt and acidity.
Edge Retention
A blade made from steel with high edge retention will stay sharp for longer across its use.
Toughness
A tough steel doesn’t chip easily when damaged. The opposite of that would be a brittle steel.
Ease of Sharpening
A steel that is easy to sharpen is easy to grind down with conventional sharpening stones, and takes less time to sharpen. A steel that's difficult to sharpen may require specialised stones and equipment for sharpening more efficiently.
Peak Sharpness (related to Grain Structure)
A steel that has a high peak sharpness has a finer grain structure. The opposite is a coarse grain structure which results in low peak sharpness.
Hardness
Usually measured in HRC (Rockwell Hardness C), hardness is a measure of the strength of bonds between the microscopic grains of steel. The stronger the bond, the harder the steel. For complex reasons, hardness is not a good indicator of edge retention when comparing across different steels, hence it will not be a point of comparison in this write-up.
Carbides
Many alloys interact with carbon in steel to produce compounds known as carbides. Carbides are extremely hard with most of them being above 70 HRC and some notable carbides reaching almost 90 HRC.
Wear Resistance
A material with high wear resistance is resistant to being scratched and worn down. For example, diamond, the hardest material on Earth, is extremely wear resistant; it is not easily scratched or worn down. The more wear resistant a steel is, the tougher it is to dull.
Powdered Metallurgy (PM)
An advanced process of making steel from powdered alloys, pressure and precise heat. The end result is a fine grained steel, usually with a high carbide concentration.
Ingot Process
The typical way of producing steel, where iron, carbon and other alloys are melted together then cast into ingots, which are further rolled into sheets or billets of steel.
RATING OF STEEL PROPERTIES
5 KEY FACTORS AFFECTING KNIFE STEELS
There are multiple factors that go into selecting your ideal knife steel. In no particular order:
1) Rust resistance / Stain resistance
A steel that is very rust resistant will not rust at all when exposed to moisture, air, salt and acidity. A rust resistant knife will be easy to care for. Knife steels can broadly be categorized into three groups - stainless, semi-stainless or carbon steel. Stainless steels generally contain more than 13% chromium and can exhibit varying levels of rust resistance. Carbon steels, on the other hand, contain less than 5% chromium, and rust easily if not kept away from moisture. Steels that have compositions between 5 and 13% could be classified as semi-stainless.
While it may seem purely advantageous to choose a knife steel that has the highest rust resistance possible, this is not without its drawbacks. A high level of rust resistance usually requires a high composition of chromium in the steel. Because chromium reacts with the carbon in steel to form chromium carbides, the more chromium is added, the larger the carbides become (for ingot processed steels). Large carbides make a steel brittle, decrease peak sharpness and also reduce edge retention as the edge chips extremely easily.
Basically, having an extremely high rust resistance comes at the cost of every other aspect that makes a knife steel good - so choose wisely. A good stainless steel for knives would usually not be immune to rusting, so don’t leave them in a wet sink overnight. However, it should be stainless enough to be left wet for an hour or two without causing a fuss.
2) Toughness / Brittleness
The opposite of a brittle steel is a tough steel. When damaged, brittle steels tend to chip, while tough steels tend to dent. All things being equal, a tougher steel would be desirable: as a dent would be easier to fix compared to a chip.
To explain why some steels are tougher than others, we need to understand the structure within the steel. A good way to visualise the structure of steel is to think of it like a concrete mix. Concrete is made up of cement which is the binder, sand which are the fine aggregates, and gravel which are the coarse aggregates. A concrete mix with different ratios of binders and aggregates will exhibit different properties. And the size of the aggregates may impact how tough or brittle a concrete mix will be.
In the case of steel, the binder is iron and the aggregates are the carbides which are formed between carbon and other alloys present in the steel. Similar to concrete, adjusting the mix of iron, carbon and alloys will influence the properties of the steel greatly. Whether the carbides are fine or coarse, depends on the size and concentration of the carbide crystals, which comes down to 3 main factors: how the steel is heat treated, its composition, as well as the process of making the steel (PM or Ingot).
One key drawback of having large carbide crystals in the steel is that it creates opportunity for fault lines to develop within the steel structure. Think about a concrete mix with only gravel inside, cracks will easily develop between the large pieces of gravel in this concrete mix. This will eventually lead to major structural failure in the concrete mix. Similarly, cracks would more easily develop in a steel with a larger carbide structure and these cracks eventually lead to chips or even worse, a crack down the blade.
In short, to avoid these issues we want a steel to have a fine grain structure with small carbides, and there are generally two ways to achieve this:
Low Alloy, Low Carbide Steel
First, is a low alloy and hence low carbide steel. In other words a simple steel with iron, carbon and little else in the way of alloys. These steels will have a very regular structure with a low density of small carbide crystals. When under stress, a fault line is unlikely to form in the fine grain structure of the steel. Hence, it is less likely to chip. An example is the White #1 (Shirogami #1) carbon steel - an extremely simple and pure steel with a mix of iron and carbon, with only a small amount of other alloys to improve steel hardness. Even when heat treated to a relatively high HRC 62-63 hardness, the steel retains a fairly high toughness.
Heat Treatment
Second, is appropriate heat treatment. The size of carbides can be minimized by heating and cooling the steel in a specific way that reduces the size of the carbide crystals that form. This specific heat treatment process would vary from steel to steel, but from experimental data we have seen, heat treating to a higher HRC hardness generally tends to reduce toughness.
With everything we have mentioned so far, there are still trade offs to choosing a higher toughness steel. For low alloy, simple steels, they generally suffer worse edge retention due to their low carbide concentration. For steels heat treated to a lower HRC for increased toughness, edge retention is also diminished as the steel is softer and deforms (rolls) more easily. When choosing a steel, it is important to consider the ratio between toughness and edge retention. A steel with decent toughness and good edge retention would be more pleasant to work with than a steel with extremely low toughness or edge retention. Again, it is all about balance.
3) Edge Retention
A knife that stays sharp even after it has been used for a long time is said to have a high edge retention. A knife’s steel can affect edge retention greatly.
A common misconception is that the HRC hardness of the steel is directly linked to edge retention. While HRC does affect edge retention, it cannot be viewed in isolation. For example, a simple low-carbide carbon steel like White #1 can achieve a high HRC of 65, but its edge retention is less than that of a softer SG2 steel with a HRC of 63. This is due to the high carbide hardness and concentration in SG2. So HRC is simply one indicator of a steel’s properties and cannot be used to fully assess the edge retention of the steel.
To more accurately assess the edge retention of the steel, we should consider these two factors:
1. Edge Stability - Influenced by Hardness (HRC) and Toughness
2. Wear Resistance - Influenced by Carbide Hardness and Carbide Concentration
Edge Stability (Hardness + Toughness)
Steel hardness is determined by two things: the composition of the steel and the heat treatment. Generally, steels with a higher carbon content have a greater potential to achieve a higher hardness with the appropriate heat treatment. Heat treatment is the process of heating and cooling steel in multiple stages so that the molecular structure within the steel arranges itself in a desirable way.
Toughness, as we discussed earlier, comes down to the grain structure of the steel. A finer grain structure in conjunction with low carbide content should yield a tougher steel.
A steel that is hard but brittle and a steel that is soft but tough will not have good edge stability. It has to be a combination of both.
If a steel is both hard and tough, it is more stable at low sharpening angles. The hardness prevents the edge from rolling (bending) and the toughness prevents the edge from chipping. From research we have seen, the more acute the sharpening angle, the higher the edge retention (by a significant margin). So the key takeaway is that if you have a knife which is both hard and tough, make sure to use the appropriate sharpening angle to get the best out of it.
Wear Resistance (Carbide Hardness + Carbide Concentration)
Carbides are crystalline compounds formed in the steel when metals (alloys) interact with carbon. They are extremely hard compounds and very abrasion resistant, which contribute greatly to a steel’s edge retention. Common carbides include:
- Iron Carbide (Cementite): approx. HRC 70
- Chromium Carbide (Cr23C6): approx. HRC 77
- Chromium Carbide (Cr7C3): approx. HRC 83
- Tungsten Carbide (WC): approx. HRC 84
- Vanadium Carbide (VC): approx. HRC 89
It stands to reason, given the hardness of these carbides, that a steel with a higher concentration of high hardness carbides will have a better edge retention.
While a highly wear resistant steel is generally desirable for knife making, it comes with some significant caveats:
- Wear resistance is inversely related to ease of sharpening; we will discuss this more in the next section.
- High carbide concentration reduces toughness, hence reducing edge stability
For the best edge retention, we want a steel with both excellent edge stability and excellent wear resistance. However, the biggest hurdle to all of this is toughness. Good wear resistance generally comes at the cost of good toughness. Thus, most steels generally fall in between a spectrum of good edge stability and good wear resistance. Having a balance of these two properties + a somewhat acute sharpening angle would give you the best of both worlds.
4) Ease of Sharpening
This is something a lot of beginners don’t consider, but a knife that is difficult to sharpen can absolutely ruin the experience of owning and using it. Granted, all knives go dull with enough use, and eventually you’ll need to bring your knife to a sharpening stone and get that sharp edge back again. However, some steels sharpen up extremely easily, some require special stones, and others simply refuse to sharpen up despite a good sharpening setup and technique.
The primary factor that determines ease of sharpening is carbide concentration.
Having a high carbide concentration makes a steel extremely difficult to sharpen, especially if you have a lower end sharpening stone. The carbides themselves are extremely abrasion resistant, which is great for edge retention, but makes it a pain in the butt to sharpen. It takes a good stone, consistent angles and a significant amount of time to sharpen a high carbide steel. But the pay off is that you don’t have to sharpen as often due to its great edge retention.
Two other factors that can influence ease of sharpening are:
Hardness
A steel heat treated to a higher hardness can be slightly more difficult to sharpen compared to the same steel heat treated to a lower level. However, you cannot use hardness to compare ease of sharpening across different steels as they may have vastly different carbide concentrations. Notably, carbon steels like White #1 that can achieve extremely high HRC of 65 are still famously considered one of the easiest steels to sharpen. On the other hand, a high carbide steel like HAP40 with a similar HRC of 65 is extremely difficult to sharpen. A steel that is particularly soft can be difficult to sharpen as well, as they do not form a proper apex and will dull and roll as it is being sharpened. This may explain why some low quality knives can never attain a good cutting edge.
Toughness
Tough steels generally sharpen up easily as they hold a stable apex, whereas brittle steels can chip as they are being sharpened. Most knife steels generally have no issues with being so brittle to the point they can’t be sharpened, so this shouldn’t be a huge consideration when selecting a knife steel.
5) Peak Sharpness
The main factor that influences peak sharpness is the grain structure of the steel.
A steel with a coarse grain structure (large carbide crystals) will generally suffer a lower peak sharpness.This is because the large carbide crystals can dislodge or chip off during the sharpening process, creating microscopic chips on the blade’s edge. This creates an edge that is, microscopically speaking, rough and jagged, hampering peak sharpness. Some steels suffer from this so badly that it is almost impossible to create a consistent edge on the blade that is sharp enough to push cut paper.
Conversely, a steel with a fine grain structure with small carbides can attain a higher peak sharpness. Do note that a high carbide steel can attain a high peak sharpness as long as the carbide size is small. This is why PM steels do extremely well with regards to peak sharpness.
INDIVIDUAL STEELS - COMPOSITION, DESCRIPTIONS, COMPARISONS
STAINLESS STEELS:
VG10 | AUS10 (Ingot)
Rust Resistance - 7/10 | Edge Retention - 5/10 | Toughness - 4/10 | Ease of Sharpening - 8/10 | Peak Sharpness - 7/10
- Carbon (C): 0.95-1.05%
- Chromium (Cr): 14.50-15.50%
- Molybdenum (Mo): 0.90-1.20%
- Cobalt (Co): 1.30-1.50%
- Vanadium (V): 0.10-0.30%
- Manganese (Mn): 0.50%
- Phosphorus (P): 0.03%
VG10 and AUS10 are made by the Japanese companies Takefu and Aichi respectively. By composition, they are relatively similar. For simplicity, we will treat them as identical steels and refer to them as VG10 (since it’s more popular) because in practice they are not really distinguishable.
VG10 is one of the most popular steels for Japanese kitchen knives due to its excellent balance of edge retention, rust resistance and ease of sharpening. For most people, their first foray into Japanese steels would be a VG10 due to its ubiquity. In this write-up, we will be making lots of comparisons to VG10 just because it's such a popular steel with overall excellent properties for knife making.
The only downside to VG10 is that if the heat treatment is not done correctly (above 61 HRC), it can be prone to chipping. However, since this steel is so popular in Japanese knife making, most manufacturers have their processes optimised for a good heat treatment so chipping really shouldn’t be much of a concern.
GINSAN (Ingot)
Rust Resistance - 7/10 | Edge Retention - 5.5/10 | Toughness - 6/10 | Ease of Sharpening - 8/10 | Peak Sharpness - 8/10
- Carbon (C): 0.95-1.10%
- Chromium (Cr): 13.00-14.00%
- Manganese (Mn): 0.60-1.00%
- Phosphorus (P): 0.03%
- Silicon (Si): 0.35%
- Sulfur (S): 0.02%
Ginsan (also known as G3, Silver 3, Ginsanko and Gingami) is made by Hitachi Metals. This stainless steel was developed to be a simple and pure steel with a fine grain structure, similar to carbon steels like Shirogami #2 (or White #2) but with 13% Chromium - enough to be considered stainless and rust resistant.
As a result, Ginsan is a stainless steel that performs like a carbon steel. It's extremely easy to sharpen, has a high peak sharpness, and has a good balance of edge retention and toughness. All this while being as easy to maintain as any Japanese stainless steel.
Compared to VG10, Ginsan is considerably less frustrating to sharpen, especially for beginners. Due to its low carbide concentration, Ginsan is easier to sharpen and deburrs more easily, resulting in a sharper edge.
One thing to note is that the performance of knife steels, including Ginsan, is highly dependent on its heat treatment. As such, the performance of the steel could differ between each knife maker and their heat treatment process. A Ginsan with good heat treatment (61-62 HRC) should have a slightly better edge retention compared to VG10, while being tougher and sharper overall.
SG2 / R2 (PM)
Rust Resistance - 8/10 | Edge Retention - 8/10 | Toughness - 4/10 | Ease of Sharpening - 4/10 | Peak Sharpness - 8/10
- Carbon (C): 1.25-1.45%
- Chromium (Cr): 14.00-16.00%
- Molybdenum (Mo): 2.30-3.30%
- Vanadium (V): 1.80-2.20%
- Manganese (Mn): 0.40%
- Silicon (Si): 0.50%
- Phosphorus (P): 0.03%
- Sulfur (S): 0.03%
SG2 is a premium powdered (PM) metallurgy steel, offering exceptional edge retention and wear resistance.
It is made by the Japanese steel company Takefu and is a direct successor to the ever popular VG10. Unlike VG10, SG2 steel is made using a process known as powdered metallurgy (PM). The PM process uses micronized powders of Iron, Carbon and other alloys and binds them together under high pressure and controlled heat to create an extremely fine-grained steel. This process allows this steel to contain a much higher carbide content while still retaining a fine grain structure which improves toughness and peak sharpness.
The resulting SG2 steel has three times the edge retention of VG10, while maintaining the same toughness with improved rust resistance. The only downside is that due to the high carbide content, it can be quite challenging to sharpen without good sharpening stones and good technique.
SG2 is also commonly referred to as R2, the latter being a brand name used by Kobelco Steel. Because both SG2 and R2 are believed to be identical in their composition and performance (with the only difference being their brand owner), both steels are often referred to interchangeably.
SG STRIX (PM)
Rust Resistance - 8/10 | Edge Retention - 8/10 | Toughness - 5/10 | Ease of Sharpening - 5/10 | Peak Sharpness - 8/10
- Composition: Unknown.
Pending write-up.
SRS13 (PM)
Rust Resistance - 8/10 | Edge Retention - 8/10 | Toughness - 5/10 | Ease of Sharpening - 4/10 | Peak Sharpness - 8/10
- Carbon (C): 1.30%
- Chromium (Cr): 13.00%
- Molybdenum (Mo): 2.75%
- Vanadium (V): 1.50%
- Tungsten (W): 1.25%
- Manganese (Mn): 0.30%
- Silicon (Si): 0.30%
SRS13 was developed by Nachi-Fujikoshi in Japan. Like SG2, SRS13 is made through the powdered metallurgy process which results in a fine-grained structure and carbides that are evenly distributed throughout the steel. SRS13 has superb edge retention and is said to be even tougher than SG2, making it a compelling alternative to SG2.
SRS13 is known for its excellent wear resistance and toughness, making it perfect for high-performance knives. With a high chromium content, it also has strong corrosion resistance, while the addition of molybdenum and tungsten provides exceptional durability and edge retention. Overall, it's an extremely well rounded steel with pretty much no downsides. However, due to the small production volume of Nachi-Fujikoshi, SRS13 supply in the market is limited and it can be quite difficult to find knives using this steel.
VG7 (Ingot)
Rust Resistance - 7/10 | Edge Retention - 5.5/10 | Toughness - 4.5/10 | Ease of Sharpening - 8/10 | Peak Sharpness - 7/10
- Carbon (C): 0.90-1.05%
- Chromium (Cr): 14.00-15.00%
- Molybdenum (Mo): 0.20-0.40%
- Vanadium (V): 0.10-0.20%
- Tungsten (W): 1.00-1.50%
VG7 is a relatively new steel that entered the market in 2022. It's actually a much newer steel compared to VG10 despite its name. As it is still relatively new, there is limited testing data and user feedback available. However, by comparing its composition to similar steels, we can better understand its properties and performance.
VG7 appears to be an optimised version of VG10, with the key difference being the addition of Tungsten. Unlike VG10, VG7 does NOT contain Cobalt, which contributes to hardness only at high temperatures above 450°C. Since kitchen knives are used at room temperature, the absence of Cobalt does not impact performance. Another notable change is the replacement of some Molybdenum in VG10 with Tungsten in VG7. While both elements contribute to hardness and carbide formation, Tungsten carbides are significantly harder - about twice as hard as Molybdenum carbides. This results in improved wear resistance without making the steel brittle. Ultimately, VG7 offers greater wear resistance compared to VG10 with a similar toughness, making it a more optimized steel.
When compared to Ginsan (Silver #3), VG7 shares a similar composition but contains Tungsten instead of Manganese found in Ginsan. As discussed, Tungsten carbides enhances wear resistance due to its exceptional hardness, while Manganese increases toughness. This suggests that VG7 is less tough compared to Ginsan but provides better edge retention at the same hardness level (HRC). Early reviews support this hypothesis, indicating that VG7 is just as fine-grained as Ginsan but maintains its sharp edge for longer.
Overall, VG7 appears to be a well-balanced and improved steel that enhances the performance of VG10 in a meaningful way. If it becomes more widely available, it could offer an exciting new option for knife makers and enthusiasts in the future.
AUS8 (Ingot)
Rust Resistance - 7/10 | Edge Retention - 4/10 | Toughness - 6/10 | Ease of Sharpening - 8/10 | Peak Sharpness - 6/10
- Carbon (C): 0.70-0.75%
- Chromium (Cr): 13.00-14.50%
- Molybdenum (Mo): 0.10-0.30%
- Vanadium (V): 0.10-0.26%
- Manganese (Mn): 0.50%
- Phosphorus (P): 0.04%
- Silicon (Si): 1.00%
- Sulfur (S): 0.03%
- Nickel (Ni): 0.49%
AUS8 is a Japanese steel made by Aichi. Like VG10, it’s a great balance of properties, but skews more towards a higher toughness and lower edge retention. It is also extremely easy to sharpen, making it a great steel for those who want easy maintenance but good performance.
AUS8 is generally more affordable, and while not as hard as some other premium steels, it’s easy to sharpen and tougher (or less prone to chipping). Its moderate hardness makes it an ideal choice for those looking for a reliable, durable kitchen knife and it’s a great entry-level steel for Japanese knives.
SEMI-STAINLESS STEELS:
HAP40 (PM)
Rust Resistance - 4/10 | Edge Retention - 9/10 | Toughness - 6/10 | Ease of Sharpening - 3/10 | Peak Sharpness - 8/10
- Carbon (C): 1.27-1.37%
- Chromium (Cr): 3.70-4.70%
- Molybdenum (Mo): 4.60-5.40%
- Vanadium (V): 2.80-3.30%
- Tungsten (W): 5.60-6.50%
- Cobalt (Co): 7.50-8.50%
HAP40 is made from the powdered metallurgy process, and arguably has the best edge retention of any steel used in modern Japanese knife making. With the right heat treatment, this steel can reach HRC 66+ while still remaining tough and durable. The alloy content of HAP40 is so high, it becomes semi-stainless, even with a low chromium content of only 4%. Compared to carbon steels, HAP40 is much more corrosion resistant and easier to maintain. However, as it is semi-stainless, do make sure to dry the blades thoroughly after washing (and oil if storing long-term).
SKD | Chromax (Ingot)
Rust Resistance - 4/10 | Edge Retention - 7/10 | Toughness - 7/10 | Ease of Sharpening - 8/10 | Peak Sharpness - 8/10
- Carbon (C): 0.95-1.05%
- Chromium (Cr): 4.50-5.50%
- Molybdenum (Mo): 0.80-1.20%
- Vanadium (V): 0.20-0.50%
- Manganese (Mn): 0.60-0.90%
- Silicon (Si): 0.40%
- Phosphorus (P): 0.03%
- Sulfur (S): 0.03%
- Nickel (Ni): 0.50%
- Copper (Cu): 0.25%
SKD (or SKD12) is a well-regarded tool steel used in high-quality kitchen knives. It’s comparable to A2 but with higher purity and a finer grain structure. Allegedly, SKD and Chromax have the same steel composition, but we cannot confirm this as official compositions of Chromax are not available.
Its impressive balance of hardness, toughness, and wear resistance makes it ideal for creating durable blades that retain sharpness for a long time. Many describe this steel as one that sharpens up as easily as Aogami #2 (Blue #2), with a superior edge retention like that of SG2/R2.
The slightly higher chromium content offers some rust resistance, resulting in its semi-stainless properties. Though not fully stainless, it maintains a sharp edge for extended periods with much easier maintenance compared to carbon steel blades.
Overall, SKD is one of the most sought after steels in Japanese knife making due to its impressive cutting performance and edge retention. Typically SKD is also clad in stainless steel making it relatively easy to maintain.
NON-STAINLESS STEELS AKA CARBON STEELS:
White #1 | Shirogami #1 (Ingot)
Rust Resistance - 1/10 | Edge Retention - 5.5/10 | Toughness - 5.5/10 | Ease of Sharpening - 9/10 | Peak Sharpness - 10/10
- Carbon (C): 1.25-1.35%
- Manganese (Mn): 0.20-0.30%
- Phosphorus (P): 0.025%
- Sulfur (S): 0.004%
- Silicon (Si): 0.10-0.20%
White #1, 2, 3 are steels produced by Hitachi, given the name White Paper Steel by the white paper that wraps this steel when it's sent to blacksmiths all over Japan.
The number behind each steel represents a different percentage of carbon in each steel, with #1 having the highest carbon content and #3 having the lowest. A higher carbon content allows a steel to be heat treated to a higher HRC (which improves edge retention), while reducing toughness. In this case, White #1 has the best edge retention but is the least tough, while White #3 has the poorest edge retention while being the toughest.
White steel is widely known to be the simplest and purest Japanese carbon steel with an extremely fine grain structure and low carbide concentration. As a result, it sharpens up extremely easily and has the highest peak sharpness of any steel we’ve tried. This may be the reason why White steel is so commonly used in sharpening tutorials and sharpening videos - to show great skill in sharpening. In reality, the steel does a lot of heavy lifting in creating a wickedly sharp edge.
However, that's where the upsides end. Apart from sharpness, White steel is extremely prone to rusting and its edge retention is pretty mediocre. Hence, we recommend looking for a blade with stainless cladding in order to combat the rusting issue. A strop would also help with the edge retention by allowing for quick touch ups in between sharpening sessions. Since the steel is so receptive to sharpening, we found that a quick stropping can maintain its edge fairly well, without needing a full sharpening session.
White #2 | Shirogami #2 (Ingot)
Rust Resistance - 1/10 | Edge Retention - 5/10 | Toughness - 6/10 | Ease of Sharpening - 9/10 | Peak Sharpness - 10/10
- Carbon (C): 1.05-1.15%
- Manganese (Mn): 0.20-0.30%
- Phosphorus (P): 0.025%
- Sulfur (S): 0.004%
- Silicon (Si): 0.10-0.20%
See White #1.
White #3 | Shirogami #3 (Ingot)
Rust Resistance - 1/10 | Edge Retention - 4.5/10 | Toughness - 6.5/10 | Ease of Sharpening - 9/10 | Peak Sharpness - 10/10
- Carbon (C): 0.80-0.90%
- Manganese (Mn): 0.20-0.30%
- Phosphorus (P): 0.025%
- Sulfur (S): 0.004%
- Silicon (Si): 0.10-0.20%
See White #1.
Blue #1 | Aogami #1 (Ingot)
Rust Resistance - 2/10 | Edge Retention - 6.5/10 | Toughness - 5/10 | Ease of Sharpening - 9/10 | Peak Sharpness - 9/10
- Carbon (C): 1.25-1.35%
- Tungsten (W): 1.50-2.00%
- Chromium (Cr): 0.30-0.50%
- Manganese (Mn): 0.20-0.30%
- Phosphorus (P): 0.025%
- Sulfur (S): 0.004%
- Silicon (Si): 0.10-0.20%
Just like White Steel, Blue #1 and #2 steels are produced by Hitachi. Instead of being wrapped in white paper, they are wrapped in blue paper, hence the name.
Blue steel #1 has a higher carbon and Tungsten content while Blue #2 has less. Correspondingly, Blue #1 has better edge retention and lower toughness, while Blue #2 has lower edge retention and higher toughness.
Compared to White steel, Blue steel has a higher alloying, with notable Tungsten and Chromium additions. These alloys improve the wear resistance of Blue steel compared to White, while only slightly decreasing toughness and peak sharpness. Overall, most would agree that Blue steel is a more balanced version of White steel, with all round improved properties.
Blue #2 | Aogami #2 (Ingot)
Rust Resistance - 2/10 | Edge Retention - 6/10 | Toughness - 5.5/10 | Ease of Sharpening - 9/10 | Peak Sharpness - 9/10
- Carbon (C): 1.05-1.15%
- Tungsten (W): 1.00-1.50%
- Chromium (Cr): 0.20-0.50%
- Manganese (Mn): 0.20-0.30%
- Phosphorus (P): 0.025%
- Sulfur (S): 0.004%
- Silicon (Si): 0.10-0.20%
See Blue #1.
Blue Super | Aogami Super (Ingot)
Rust Resistance - 2/10 | Edge Retention - 7.5/10 | Toughness - 5/10 | Ease of Sharpening - 7/10 | Peak Sharpness - 8/10
- Carbon (C): 1.40-1.50%
- Tungsten (W): 2.00-2.50%
- Vanadium (V): 0.30-0.50%
- Chromium (Cr): 0.30-0.50%
- Manganese (Mn): 0.20-0.30%
- Phosphorus (P): 0.025%
- Sulfur (S): 0.004%
- Silicon (Si): 0.10-0.20%
Aogami Super (AS) has the highest edge retention among the Aogami Steel (a.k.a. Blue Steel) series made by Hitachi - there’s “Super” in its name after all. Consequently, it happens to be one of the most popular carbon steels in Japanese knife making.
There is a lot to love about AS. Its relatively simple composition leads to a fine grain structure which allows for excellent peak sharpness. The addition of small amounts of Vanadium, Chromium, Manganese and Tungsten creates small and dispersed carbides throughout the grain structure of the steel, allowing AS to reach a high working hardness without too much loss in toughness. Because of the high hardness, good toughness and high peak sharpness, AS is widely known to have the best cutting feel of any Japanese steel. The sound that AS makes when it cuts hits different: the pitch is high and the sound is clear. It's unusual, in a good way.
Probably the only real downside is the rusting. But this downside is overcome by something that doesn’t get mentioned enough - AS has a wide availability in stainless clad formats. Stainless cladding really allows the steel to shine with its incredible cutting feel and performance, while keeping it easy to maintain.
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