SG2 vs VG10 Steel

VG10 and SG2 (Super Gold 2) are produced by Takefu Special Steel, a renowned Japanese knife steel company specializing in high-quality blade steels.

VG10 is a conventional carbon steel incorporating chromium, molybdenum, vanadium, and a unique cobalt addition for enhanced tempering resistance.

In contrast, SG2 is a more modern powder metallurgy stainless steel and patented as a super high-grade blade steel explicitly designed for cutlery.

The powder metallurgy process allows for a finer, more uniform microstructure and the incorporation of higher alloy contents, resulting in a tougher, more wear-resistant steel.

These blade steel have earned a reputation for their wear resistance, and ease of sharpening, making them popular choices for kitchen knives and general-purpose EDC knives.

SG2 vs VG10 Steel At A Glance

Hardness

VG10 is a conventional stainless steel with a maximum hardness of around 60 HRC while SG2 is a powder metallurgy stainless steel with a slightly higher maximum hardness of 62 HRC.

VG10 Knife steel hardness is achieved by adding chromium, molybdenum, vanadium, and a unique cobalt content of 1.55%. 

VG10 Cobalt addition contributes to the ability to retain hardness at higher tempering temperatures, making it suitable for knives that require surface coatings applied at very high temperatures.

SG2 powder metallurgy process allows for a more uniform and fine-grained microstructure, as well as the ability to incorporate a higher amount of alloying elements compared to conventional steelmaking methods.

This results in better hardness and wear resistance for SG2. Like VG10, SG2 is also designed to maintain its hardness and properties even when subjected to high-temperature ceramic or fluoropolymer coatings.

Toughness

According to toughness tests conducted by Dr Larrin using the subsize unnotched Charpy impact test, SG2 exhibited superior toughness compared to VG10. 

Specifically, SG2 averaged 6.5 ft-lbs in the toughness test, while VG10 averaged 5.8 ft-lbs. This places SG2 toughness slightly higher than VG10 and in line with S45VN.

The higher toughness of SG2 can be attributed to its powder metallurgy production method, which results in a more uniform and fine-grained microstructure with reduced segregation and impurities.

This fine microstructure contributes to improved toughness and resistance to chipping or fracturing, which is crucial for knife steels that may encounter impact forces during use.

In contrast, VG10 blade steel toughness, while still respectable for high-hardness stainless steel, is slightly lower than SG2. 

This could make VG10 knives more susceptible to chipping or cracking under heavy impact loads, especially at the higher hardness levels required for optimal edge retention.

Edge Retention

SG2 (Super Gold 2) steel exhibits slightly better edge retention and or wear resistance compared to VG10 steel.

The wear resistance and edge retention of steel are primarily determined by the type, volume, and distribution of carbides present in the microstructure. 

SG2 powder steel has a very fine and uniform distribution of carbides, including hard vanadium carbides (approximately 0.5% by volume).

In contrast, VG-10 has a higher volume of chromium carbides (estimated 12-16%) but lacks the vanadium carbides in SG2. 

While chromium carbides contribute to wear resistance, vanadium carbides are even harder and more effective at maintaining a keen edge under heavy use.

Experimental CATRA slicing-edge retention testing ranked VG10 slightly below 440C stainless steel, which is expected based on its carbide composition.

On the other hand, SG2’s edge retention is estimated to be higher than VG10, 440C, and CPM-154, placing it slightly below steels like S30V and S35VN, which are known for their excellent edge retention.

Additionally, when it comes to edge stability, SG2 will offer better edge stability thus avoiding chipped or rolled edges due to slightly higher toughness.

Corrosion Resistance 

VG10 and SG2 (Super Gold 2) are stainless steels with excellent corrosion resistance, making them suitable knife steels.

Dr Larrin’s corrosion resistance tests, which were conducted by spraying the steels with distilled water and 1% salt water solutions, showed that VG10 and SG2 passed the initial stainless test.

In the more rigorous 1% salt water test, SG2 performed slightly better than expected based on its chromium and molybdenum content in solution, while VG10 performed roughly as predicted by its alloy composition.

This suggests that SG2 may have a small advantage in terms of overall corrosion resistance compared to VG10.

Furthermore, the addition of molybdenum in SG2 (around 2.4% in solution) likely contributes to its improved corrosion resistance over VG10, which has a lower molybdenum content (0.9% in solution).

Molybdenum is known to enhance the pitting and crevice corrosion resistance of stainless steel, making SG2 more resistant to localized corrosion attacks.

Ease of sharpening

 VG10 steel has good machinability and is relatively easy to sharpen, this can be attributed to the absence of vanadium carbides in its microstructure. 

Vanadium carbides are harder than the commonly used aluminium oxide abrasives, making steels with high vanadium carbide content more difficult to polish and sharpen to a fine edge.

SG2 does contain a small amount of vanadium carbides by volume. While this vanadium carbide content is lower, it may still present some challenges during sharpening and finishing compared to VG10.

However, the fine and uniform microstructure of SG2, resulting from the powder metallurgy process, can mitigate some of the challenges associated with sharpening vanadium-rich steels.

The absence of large, segregated carbides, which can be more difficult to abrade, likely makes SG2 easier to sharpen than conventional steels with similar vanadium carbide content.

I would like to point out that the difference in ease of sharpening is highly subjective as the hardness plays an important role, also the difference in sharpening these two steels is quite minimal.

Cost

An important factor to consider when choosing between VG10 and SG2 for knife applications is the cost difference between these two steels.

Generally, knives made from SG2 steel command a higher price point compared to those made from VG10 steel. 

This cost premium can be attributed to the more complex and specialized powder metallurgy process used in the production of SG2.

Final Thoughts on SG2 vs VG10 Steel

In conclusion, while both steels exhibit good hardness, wear, and corrosion resistance, SG2’s powder metallurgy production method and unique alloy composition give it a slight edge over VG10.

My personal experience with these steels has been fulfilling. Due to its wider availability, I have had more extensive experience with VG10.

VG10 has proven to be an excellent budget steel for pocket knives and a capable choice for kitchen knives, offering a compelling balance of performance and affordability.

While SG2 superior toughness and edge retention are evident in direct comparisons, the differences were relatively minimal in independent, day-to-day usage scenarios.