The kitchen knife steel grade is one of the most important performance characteristics, which, nonetheless, is often underestimated by the consumer. After all, the knife performance and durability depend largely on the steel grade.
Steel is an alloy of iron and carbon. Due to the substantial iron content, steel is prone to corrosion and has properties that are inadequate for knife making. Therefore, it has various alloying additives typically added to its composition to significantly increase its performance characteristics, namely, molybdenum, chromium, vanadium, silicon, manganese, and many others. It is exactly these additives that give blades of each specific brand certain properties such as hardness, strength, elasticity, wear and corrosion resistance, viscosity, etc.
The steel grade, its quality and "professional suitability" as knife steel are based on the individual composition of these additives, their percentage ratio, and, of course, the features of hardening and nuances of manufacturing process.
The AUS-8 and VG-10 steel grades designed specifically for this purpose are usually used as steel for Japanese kitchen knives.
AUS-8: Cost-Effective and High-Quality Kitchen Knife Steel
The AUS-8 kitchen knife steel from Aichi Steel Works is a perfect compromise between harder steels with increased brittleness and softer steels with poor blade hold.
Hardening at 1040-1600°C gives it a hardness of 56-59 HRC, which allows the blade to preserve an impeccable sharpness for extended periods. A high content of carbon (approx. 0.8%), vanadium, molybdenum and other additives give AUS-8 the necessary resistance to corrosion, wear and mechanical damage.
Knives made of this steel are able to confidently bear lateral and chopping loads, are not prone to chipping and other defects, are immune to high temperatures and moisture, and are generally very unpretentious, which is ideal for cooking. They require no special grinding tools and can be sharpened even at home.
However, AUS-8 kitchen knife steel manufacturing processes are not that time-consuming and cost-intensive, thus allowing to set quite attractive prices for knives given their first-rate quality and excellent cutting performance.
VGold10: Expensive Kitchen Knife Steel
The VG-10 kitchen knife steel was developed by the Japanese company Takefu Special Steel Co., Ltd. Its carbon content (0.95-1%) is greater than that of AUS-8. In addition to molybdenum, vanadium, and chromium, VG-10 is also alloyed with cobalt, i.e. an expensive additive that is rarely found in knives, however, multiplies its mechanical properties, hardness, and toughness (ability to withstand shock loads).
VG-10 is one of the best knife steels and, accordingly, is rather expensive. It is this steel that allows to conduct hardening of tools made of it to 60-63 HRC. Given professional sharpening, it is easily brought to razor sharpness, while preserving the splendid cutting performance for a long time.
However, VGold10's high hardness makes it quite brittle; therefore, it often serves as the core of Damascus steel knives, overlaid with numerous layers of steels with lower carbon content. They do not only reduce the load on the central part, but also extend the duration of the already impressive kirenaga, as well as serve as another barrier for corrosive processes. And, of course, add extraordinary beauty to multi-layered blades.
In addition, the VG-10 kitchen knife steel is quite suitable for sharpening with a honing rod. Theoretically, it can even be sharpened at home, although it is better to have such expensive knives sharpened by a professional.
Blackened Kitchen Knife Steel
Just like it is alloyed to obtain the necessary properties, kitchen knife steel is also subject to blackening
During this chemical process, steel is exposed to high temperatures, acids or alkalis merely to form iron oxide on the blade surface, i.e. a thin film that gives the blade a unique bluish-black color. However, any shade can be obtained by adjusting the time and temperature of heating. After that, the surface is impregnated with special oils and ground.
In addition to a unique aesthetic effect, blackening has also a protective function to perform where it passivates steel to make it totally immune to corrosion and aggressive environmental effects.
The Samura knife collection did not do without the use of this unique technology. Both Sakai and Kaiju series are a fine example of how the union of Damascus and blackened steels makes it to an excellent option for creating incredibly beautiful knives of high quality. Sharp, professional, and always looking attractive. A combination that is difficult to resist.
Such a decorative trim for kitchen knife steel further improves their reliability and durability by giving the already impeccable Japanese tools a legendary quality and unrivaled performance.