VG10 vs S30V Steel

S30V manufactured by Crucible Industries through the powder metallurgy process, is a martensitic stainless steel designed for optimal toughness, wear resistance, and corrosion resistance. 

VG10 developed by Takefu Special Steel in Japan using conventional steel making methods.

It is a high-chromium steel known for its edge retention capabilities and the unique addition of cobalt.

VG-10 incorporates a small amount of cobalt, an uncommon alloying element in knife steels, which is claimed to enhance the effects of other elements.

A key area where S30V demonstrates a distinct advantage over VG10 is in its superior edge retention and wear resistance. 

VG10 vs S30V Steel At A Glance

Hardness

S30V can achieve hardness up to around 64 HRC with proper heat treatment, and is typically tempered to the 58-61 HRC range for knives according to the Crucible data sheet.

On the other hand, Takefu states that  VG10 achieves a hardness of less or equal to 60.7 HRC when heat treated using recommended temperatures.

This suggests that S30V and VG-10 can achieve fairly similar peak hardness levels in the 60-61 HRC range when properly heat treated, though S30V may have a slight edge in maximum attainable hardness. 

Edge Retention

S30V steel exhibits superior edge retention and wear resistance compared to VG10 steel.

This is primarily due to the higher volume fraction of hard vanadium carbides present in the microstructure of S30V.

Vanadium carbides are more effective at resisting wear and maintaining a keen edge during use.

While VG10 contains chromium carbides that contribute to wear resistance, these are softer and less wear resistance than the vanadium carbides found in S30V.

The addition of 4% vanadium in CPM S30V composition allows for the formation of a greater amount of the harder vanadium carbide particles, enhancing its overall wear resistance and edge retention.

Experimental data from CATRA (Cutlery & Allied Trades Research Association) testing, which evaluates the number of cuts a steel can make through abrasive material, supports S30V superior wear resistance. 

The results indicate that S30V relative edge retention is approximately 45% higher than that of VG10, demonstrating its ability to maintain a sharper edge for longer periods of use.

Furthermore, the powder metallurgy production process used for S30V results in a finer and more homogeneous distribution of these hard vanadium carbides throughout the microstructure,

Powder Metallurgy further contributes to its improved wear resistance and edge-holding capabilities when compared to the more conventional VG10 steel.

Toughness

Toughness is a critical property for knife steels, as it determines the ability of the blade to withstand impact and resist chipping or fracturing during use. 

S30V and VG10 steels exhibit similar or comparable levels of toughness based on experimental results

Toughness tests using 1/4 size unnotched Charpy specimens, show that VG10 averaged 5.8 ft-lbs while S30V averaged 6.5 ft-lbs when both were heat treated to around 60 HRC hardness.

These toughness values are quite close, with S30V steel being only  negligibly higher than VG10 steel. 

Transverse Charpy C-notch testing also show that CPM S30V and VG10 steel achieve closely similar  impact energy at around 10 ft.lbs.

VG10 contains primarily chromium carbides, while S30V has a significant amount of vanadium carbides which tend to be smaller and provide better toughness compared to chromium carbides.

However, the similar toughness values are attributed to the fact that the carbide volume itself is more the limiting factor for these steels rather than just the carbide type. 

VG-10 micrographs show it has an estimated 12-16% carbide volume, which is comparable to S30Vs carbide volume of 14.5%.

Corrosion Resistance

S30V and VG10 steel are both stainless steel with excellent corrosion resistance, they exhibit better corrosion resistance than the likes of AUS 8 and 154CM Steel.

S30V and VG10 blade steels exhibit comparable levels of corrosion resistance, with neither steel exhibiting a clear advantage over the other.

Although VG10 has a slightly higher chromium content of 15% compared to S30V 14%, the presence of other alloying elements in S30V, such as molybdenum and nitrogen, helps to offset the potential advantage of VG10 higher chromium content.

Ease of Sharpening

VG10 steel exhibits better grindability and ease of sharpening compared to S30V steel. This advantage can be attributed to the differences in their carbide compositions and microstructures.

VG10 contains primarily chromium carbides, which are softer and less abrasive to grinding media compared to the harder vanadium carbides present in S30V.

The absence of significant amounts of vanadium carbides in VG-10 makes it more forgiving during sharpening and grinding processes, reducing the time to sharpen your knife.

VG10 microstructure, dominated by the softer chromium carbides and occasional larger carbides, is relatively easy to polish and sharpen, similar to other steels like 440C or 19C27.

Final Thoughts on VG10 vs S30V Steel

Having owned and used EDC pocket knives and kitchen knives made from both S30V and VG10 steels, I can attest to the exceptional qualities each steel provides.

CPM S30V stainless steel holds a distinct advantage in terms of its superior edge retention capabilities.

VG10 may slightly trail S30V in edge retention, but its superb grindability and ease of sharpening make it an excellent option, particularly for kitchen knives that require frequent sharpening to maintain peak performance. 

Ultimately, both S30V and VG10 are outstanding stainless steels, and I would confidently recommend either based on the specific priorities of edge retention versus sharpening ease for the intended application.

Spyderco has been using these two steels interchangeably in their  series of knives an attestment to how good both are.