When reading information about a knife you may see details of hardness of the blade, for example 60 ±2HRC. This rating is referred to as the Rockwell scale.
The Rockwell scale dates back to 1919 when Stanley Rockwell, a metallurgist in a ball bearing factory in New England, developed the scale to measure the hardness of bearing races. The scale quickly started to be used by manufacturers who used steel and needed a way to rate it.
So what are the ratings and what do they mean?
Below 52 HRC |
Steel is too soft to make knives |
52-54 HRC |
Soft steel making reasonable quality knives |
54-56 HRC |
The hardness of many French chefs’ knives. While the steel is hard enough to use in the kitchen, the knives need regular sharpening although they do sharpen easily. |
56-58 HRC |
The hardness of many German knives. This steel remains sharp long enough to be used in a kitchen and is reasonably easy to sharpen. |
58-60 HRC |
This is the hardness you find in quality kitchen knives from Japan. These knives remain sharp for considerably longer than knives with lower HRC ratings but are more difficult to sharpen. |
60-62 HRC |
These knives stay sharp for a long time but can become brittle and are difficult to sharpen. |
63-66 HRC |
Knives with this hardness of steel become brittle and result in the blades breaking if not used properly. These knives also have a higher likelihood of corroding. |