Aogami Super vs R2/SG2

In our today's post, we will be comparing two well-established, excellent and popularly used knife steels: Aogami Super produced at Hitachi Steels and R2/SG2 distributed by Kobelco Steel Company/Takefu Steel Company. Which one will prove to be better? Find out for yourselves!

1. Composition comparison

Element	Aogami Super	R2/SG2
Carbon (C)	1.40 - 1.50%	1.25 - 1.45%
Tungsten (W)	2.00 - 2.50%	-
Vanadium (V)	0.30 - 0.50%	1.80 - 2.20%
Chromium (Cr)	0.30 - 0.50%	14.00 - 16.00%
Molybdenum (Mo)	0.30 - 0.50%	2.30 - 3.30%
Manganese (Mn)	0.20 - 0.30%	0.40%
Silicon (Si)	0.10 - 0.20%	0.5%
Phosphorus (P)	0.025%	0.03%
Sulfur (S)	0.004%	0.03%

 

1. Properties and microstructure

First and foremost, these two compared steels are two different types. Aogami Super is a carbon steel with a limited amount of alloying additives, but with a significant proportion of tungsten. On the other hand, R2/SG2 steel is a high-speed powdered steel that is impervious to corrosion.

R2/SG2 can be classified as corrosion-resistant steel, which is a great advantage, although it is at the expense of lesser strength and durability. Therefore, carbon steels enriched with tungsten are potentially better in terms of these properties. Moreover, in terms of usability and structure, R2/SG2 steel has a significant presence of carbides in the structure, which results in elevated abrasion resistance but, at the same time, reduces durability and edge stability quite significantly. High abrasion resistance and a significant amount of retained austenite can make it challenging to sharpen.

In contrast, Aogami Super is a tungsten tool steel. Tungsten in carbon steel increases yield strength and hardness but reduces impact toughness. This steel is not resistant to rusting, but it is more resistant than typical carbon steel. The combination of limited corrosion resistance and reduced impact toughness makes it susceptible to chipping. On the other hand, the carbide content (due to chromium, vanadium, and tungsten) improves abrasion resistance compared to plain carbon steels. Limited retained austenite makes knives made out of this material easier to sharpen. Moreover, users of Aogami Super value it for high edge stability. It is appreciated for its extraordinary sharpness, which ensures silky smooth cutting. Due to its inclination to chipping and restricted corrosion resistance, a good compromise is using Aogami Super as the core in lamination with softer stainless steel.

III. Verdict

It is not easy to compare these two kinds of steel; it is a bit like comparing apples to oranges. Although they are characterized by similar hardness, R2/SG2 might be insignificantly more resistant to abrasion, but Aogami Super should be easier to sharpen. In the end, the main difference is the ‘comfort’ of corrosion resistance of R2/SG2 steel.

Both Aogami Super and R2/SG2 are high-quality steels favored by skilled craftsmen for their knives. Aogami Super, known for its purity and sharpness retention, is often used with a core of softer stainless steel to mitigate its susceptibility to rust and chipping. On the other hand, R2/SG2 steel offers exceptional hardness and wear resistance, surpassing many powdered steels. It also maintains sharpness well and is easy to sharpen. While Aogami Super is well-regarded for its ideal and simple composition, R2/SG2 stands out for its hardness, toughness, and corrosion resistance, making it a top choice for demanding professionals. The choice between these two steels ultimately depends on specific preferences and needs.