S90V vs S110V Steel

CPM S90V and CPM S110V premium stainless steels represent the evolution of high-vanadium knife steels from Crucible Industries.

S90V and S110V are known for their exceptional wear resistance and edge retention, surpassing many other stainless steels in the market.

The key to their performance lies in their high vanadium content, with both steels containing 9% vanadium.

This high vanadium content forms extremely hard carbides that contribute to their superior edge-holding capabilities.

However, S110V takes the composition a step further by incorporating 3% niobium and increasing the chromium content to 15.25% (compared to 14% in S90V).

This modification in S110V’s composition results in some key differences in properties between the two steels.

While S90V offers slightly better toughness and edge retention, S110V boasts superior corrosion resistance, making it more suitable for applications in harsh environments.

S90V vs S110V Steel At A Glance

Hardness

S90V and S110V steels can achieve similar levels of hardness, with both capable of reaching approximately 60-63 HRC when properly heat treated.

S90V can achieve hardness up to 66 HRC with appropriate heat treatment, while S110V’s aim hardness is stated as 56-59 HRC in the Crucible datasheet, though it can reach higher values. 

The hardness potential of these steels is comparable, with S90V possibly having a slight edge in maximum achievable hardness.

For knives, this high hardness translates to excellent wear resistance and edge retention for both steels.

However, the extremely high hardness also makes both steels more challenging to sharpen and work with during knife manufacturing processes.

Toughness

S90V steel demonstrates slightly better toughness compared to S110V steel.

In toughness tests, S90V achieved values similar to other powder metallurgy stainless steels like S60V, S30V, and M390, while S110V fell slightly below this level.

S90V benefits from a lower overall carbide content and a finer carbide structure compared to S110V, which contains additional alloying elements like niobium.

The presence of niobium in S110V contributes to smaller carbides, but the overall higher carbide volume slightly reduces its toughness relative to S90V.

S90V knives potentially have a slight edge in impact resistance and ability to withstand lateral stresses without chipping or breaking.

However, S90V and S110V steels are still considered to have relatively low toughness compared to less highly alloyed steels.

The toughness of both steels is influenced by their high vanadium content, which forms hard carbides that enhance wear resistance but can reduce overall toughness.

The carbon content, heat treatment, and distribution of carbides also play crucial roles in determining the final toughness.

Despite S90V’s slight advantage in toughness, both steels are primarily chosen for their exceptional wear resistance and edge retention in knife applications.

Edge Retention

S90V steel demonstrates slightly better edge retention compared to S110V steel in CATRA testing.

The CATRA (Cutlery and Allied Trades Research Association) tests showed that S90V achieved higher edge retention values than S110V, with S90V being one of the highest performing stainless steels tested.

This superior edge retention in S90V can be attributed to its high vanadium content (9%) and optimal chromium level (14%), which promotes the formation of hard vanadium carbides while maintaining sufficient chromium for corrosion resistance.

S110V, despite having a similar vanadium content, includes additional elements like niobium and higher chromium (15.25%), which may slightly reduce the formation of vanadium carbides.

For knives, this translates to S90V potentially maintaining a sharp edge for longer periods during use, particularly in demanding cutting tasks.

However, both steels offer exceptional edge retention compared to most other stainless steels.

The edge retention of both steels is influenced by their high vanadium and carbon content, which form hard carbides that resist wear. 

The distribution and size of these carbides, affected by the steel’s composition and heat treatment, play crucial roles in determining the final edge retention performance.

Corrosion Resistance 

S110V and S90V are stainless steels, however, S110V steel demonstrates superior corrosion resistance compared to S90V steel.

In corrosion tests, S110V performed significantly better than S90V, with corrosion resistance levels similar to or better than M390, another highly corrosion-resistant steel.

S110V’s enhanced corrosion resistance can be attributed to its higher chromium content (15.25% vs 14% in S90V) and the addition of niobium, which helps keep more chromium in solution.

S90V, while still considered corrosion-resistant, falls into the middle range of stainless steels in terms of corrosion performance.

For knives, this means that S110V would be a better choice for applications involving frequent exposure to corrosive environments, such as marine use or food processing.

S110V knives would be less likely to develop rust or stains, potentially maintaining their appearance and performance longer in challenging conditions.

The corrosion resistance of both steels is primarily influenced by their chromium content, with chromium forming a protective oxide layer on the surface.

Additionally, the presence of molybdenum in both steels (2.25% in S110V and 1% in S90V) further enhances corrosion resistance, particularly against pitting corrosion.

The niobium in S110V plays a crucial role by forming carbides preferentially over chromium, leaving more chromium available in the steel matrix for corrosion protection.

Ease of Sharpening

S90V and S110V steels are known for their difficulty in sharpening and grinding, with S110V being slightly more challenging to work with.

This difficulty stems from their high vanadium content, which forms extremely hard carbides that resist abrasion.

S90V is described as very difficult to grind and finish, with early knifemakers like Barry Gallagher, P.J. Tomes, and Phil Wilson all agreeing on its challenging nature.

S110V, having a similar vanadium content plus the addition of niobium, is reported to be comparable to or slightly more difficult than S90V in terms of machinability and grindability. 

For knives, this means that both steels require more time and effort during the manufacturing process, potentially increasing production costs.

Sharpening these steels is also more demanding for end-users, often requiring diamond or CBN (Cubic Boron Nitride) abrasives, as conventional aluminum oxide stones are less effective due to being softer than the vanadium carbides present in both steels.

The difficulty in sharpening can be a drawback for some users, particularly those who frequently resharpen their knives.

However, this challenge is offset by the exceptional edge retention of both steels, which means less frequent sharpening is required.

Knife users working with either S90V or S110V need to be prepared for longer grinding and sharpening times, and may need to invest in specialized tools or abrasives.

While both are challenging, S110V is considered more difficult to sharpen due to its additional alloying elements, making S90V slightly preferable

Final Thoughts on S90V vs S110V Steel

In comparing S90V and S110V, it’s clear that both steels represent the pinnacle of high-wear resistance stainless knife steels.

S90V, with its slightly better edge retention and toughness, remains an excellent choice for those prioritizing cutting performance above all else.

However, S110V steel improvements, particularly in corrosion resistance is an added advantage. 

The addition of niobium in S110V allows for better chromium distribution and enhanced rust resistance without sacrificing too much in terms of wear resistance. 

Both S90V and S110V are challenging to work with due to their high vanadium content, but this is the trade-off for their exceptional edge retention. 

For those in corrosive environments, S110V is the clear winner, while hardcore cutting enthusiasts might prefer the edge retention edge of S90V.

Regardless of the choice, both steels represent remarkable achievements in metallurgy, pushing the boundaries of what’s possible in a stainless knife steel.