Rockwell Hardness (HRC) & Steel Types

There are multiple steel types, and each steel type has its own name and composition. One of the metrics to make it easier to indicate edge retention is the Rockwell rating. In general, you can say the higher the Rockwell, the longer the edge retention. But the higher the Rockwell, the more brittle the knife will be. The same can be said for a lower Rockwell. The lower the Rockwell, the faster the knife will get dull, but you get a more durable knife.

Info: The steel composition, thickness, and knife style have a major role in some metrics. A Rockwell rating is just one indication to make it easier for customers to grasp what the knife can do.

HRC, RC, or Rockwell

Here is a brief overview of the Rockwell Hardness:

• 52-54 HRC: Cheap chef’s knives, mostly very cheap 8 euro (10 dollars). It needs to be sharpened every time we are done with a task.
• 54-56 HRC: Better than cheap knives. Mostly for home cooks and not for the professional kitchen. Chinese bone cleavers use this kind of hardness. It needs to sharpen a few times a day if used in a professional kitchen.
• 56-58 HRC: Easy to sharpen and used in a professional kitchen. Mostly german knives or better quality Chinese vegetable/bone cleavers use this kind of hardness.
• 58-60 HRC: Better quality kitchen knives like Japanese knives. They stay longer sharp but are harder to sharpen.
• 60-62 HRC: The knives remain sharp for a long time but have more risk of becoming brittle. Harder to sharpen, and quality depends on the production. Mostly used in Japanese knives.
• 63-66 HRC: Needs cleaning after each use and more prone to breaking and becoming brittle. Some steel types with this high HRC need a wet towel wipe before each slice.

Info: Of course, these are just guidelines. The manufacturer, steel type, and knives are made a huge role in the quality. We also have powdered steel which can reach a Rockwell beyond 66 and are still stainless.

Steel types

We can go deep into each steel type, but we only need to know three types: stainless, high-carbon, and powdered steel. Each steel type has its pro and cons depending on the purpose of the knife.

Stainless Steel

Stainless steel is exactly as the word says it is. It ”stains” ”less,” great rust resistance, and can be exposed to water for a long period of time. Some stainless steel can be put in the dishwasher without rusting. However, this is inadvisable since it is not good for the steel and the edge. Long exposure to a salty water bath will rust no matter how good the stainless properties are.

Japanese High Carbon steel

High Carbon steel is the preferred choice of Japanese chefs because it has a High Carbon content, and therefore it can be hardened above 60+ HRC. They are easy to resharpen and can take a very clean and sharp edge. However, they need a lot of maintenance and care, or they will rust.

Info: High Carbon is the preferred choice of Japanese chefs because it has a High Carbon content, and therefore it can be hardened above 60+ HRC. They are easy to resharpen and can take a very clean and sharp edge, however.

Powdered Steel

With modern science, we now have Powdered steels; they can be hardened above 66 on the Rockwell Scale and have excellent corrosion resistance. They can stay longer sharp than High Carbon steels, but sharpening is slightly harder.

Steel Composition

It is the combination of steel that gives a certain knife it hardness purity and rust resistance layers:

• Carbon (C): Increase edge retention, but also makes the steel more brittle (the more ”C,” the higher the Rockwell).
• Chromium (Cr): Corrosion resistance (minimal 13% so that we can call it ”stainless”)
• Manganese (Mn): improves steel structure and increases the possibility for higher hardening of steel.
• Vanadium (V): A combination of wear, toughness, strength and allows the blade to take a sharp edge for a longer period.
• Molybdenum (Mo): Preventing brittleness.
• Silicon (Si): increases the positive effects of carbon (C). It increases the hardness and the power of steel.
• Cobalt (Co): Increase strength and hardness (and good for quenching in higher temp).
• Tungsten (W): Increases the wear resistance of steel.

(There are more but they all compliment each other or do the same thing)

Example:

So let’s say AUS10 60HRC:
C: 0.96%
Cr: 14.9%
Mo: 0.9%
V: 0.10%

Now VG10 60HRC:
C: 0.95%
Cr: 14.5%
Mo: 0.8%
V: 0.20%
Co: 1.3%

Despite the lower C in the VG10 it has similar edge retention and sharpness and most likely even sharper than AUS10.
Because the added Co in the VG10 allows for higher quenching.
Cr in VG10 is lower than AUS10 but both are above 13% so both have excellent rust resistance.
The AUS10 has a higher Mo than the VG10 making the knife stronger against chipping vs VG10.
Due to the added V, in the AUS10 the AUS10 is more durable and can hold the edge longer than the VG10.

Despite having a higher C the rest is what makes a knife steel composition important.

In the above scenario, the VG10 will take a sharper edge while having similar edge retention.
The AUS10, on the other hand, will be more durable while having a Similar Rockwell as the VG10.

Note: Example of steel composition and mixtures, for exact measurements see the manufacturers description

For more comparision you can visit ”steel type” overview page.

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