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S35VN vs D2 Steel: What is the Difference Between Them?

July 11, 202436 ViewskniveSource

Contents

D2 is a conventional air-hardening, high-carbon, high-chromium tool steel produced by various manufacturers, including Niagara Specialty Metals.

S35VN is powder metallurgy stainless steel developed through Crucible’s proprietary CPM process, it boasts a carefully balanced composition of chromium, vanadium, niobium, and molybdenum. 

In contrast, D2 is a conventional high-chromium tool steel, relies primarily on chromium carbides for its wear resistance. 

While both steels excel in various applications, including knives, S35VN distinguishes itself with superior toughness and corrosion resistance.

The powder metallurgy process employed in S35VN production results in a refined, homogeneous microstructure, enhancing its toughness and impact resistance compared to the relatively coarse structure of D2. 

S35VN vs D2 Steel at A Glance

PropertyD2 SteelS35VN Steel
HardnessCan achieve up to 64 HRC hardness.Can achieve up to 64 HRC hardness
ToughnessRelatively low toughnessSignificantly higher toughness compared to D2.
Edge RetentionGood edge retentionComparable edge retention to D2
Corrosion ResistanceNon stainless steelSuperior corrosion resistance as a stainless steel
Ease of SharpeningSlightly easier to grind, machine, and polish compared to S35VN.Somewhat more challenging to sharpen and grind.

S35VN vs D2 steel comparison

Hardness

Both D2 steel and S35VN steel can achieve comparable high levels of hardness of up to 64HRC with proper heat treatment.

For S35VN, Crucible recommended heat treatment enables it to reach an aim hardness of 60-61 HRC, with a maximum attainable hardness of at least 64 HRC.

D2 steel is known to reach hardness levels up to around 64 HRC with suitable austenitizing and tempering procedures, however, it is mostly heat treated in the lower 60s HRC.

The high attainable hardness in both steels is facilitated by their respective hard carbide constituents. 

Chromium carbides in D2, and a combination of vanadium, niobium, and chromium carbides in the powder metallurgy S35VN.

Toughness

S35VN steel exhibits significantly better toughness compared to D2 steel.

Testing data shows that S35VN achieved Charpy C-notch impact energy values of around 25-28 ft-lbs, while D2 steel is reported to have toughness values in the lower 14-15 ft-lbs. 

D2 steel toughness is roughly equivalent to CPM 10V, which has relatively low toughness among tool steels. 

S35VN has better toughness than D2 across a wide range of hardness levels. 

This enhanced toughness in S35VN can be attributed to its refined microstructure resulting from the powder metallurgy process, as well as the presence of niobium carbides, which are more effective in improving toughness compared to the chromium carbides found in D2.

Additionally, the lower carbon content of S35VN relative to higher carbon tool steels like D2 inherently contributes to its higher toughness.

Overall, the information unambiguously demonstrates that the premium powder metallurgy stainless steel S35VN possesses markedly better toughness properties than the conventional high-chromium tool steel D2.

Edge Retention

D2 steel and S35VN steel exhibit comparable levels of edge retention and wear resistance.

Crucible CATRA edge retention testing ranks S35VN at around 145% relative to 440C stainless steel, similarly D2 steel is rated slightly at approximately 145% of 440C. 

However, this difference is relatively small, suggesting that their edge retention performance is highly similar.

D2 and S35VN steels rely on hard carbide particles, primarily chromium carbides in D2 and a combination of vanadium, niobium, and chromium carbides in S35VN, to provide excellent wear and edge retention properties. 

While S35VN may have a slightly finer carbide structure due to its powder metallurgy production, the difference does not appear to translate into a substantial edge retention superiority over the conventional D2 tool steel. 

D2 steel and S35VN steel exhibit edge retention and wear resistance properties that are highly comparable, with no discernible major difference between the two steels in this aspect of performance.

Corrosion Resistance

S35VN steel is a stainless steel while D2 steel is a non stainless steel. S35VN steel exhibits superior corrosion resistance compared to D2 steel.

Test data by Dr. Larrin shows that S35VN scored a corrosion resistance rating of 7.5 out of 10 based on pitting potential testing, which is excellent for a high-alloy martensitic stainless steel.

In contrast, D2 is considered to have good corrosion resistance for a tool steel due to its high chromium content of 12% but significantly low when compared to S35VN

Half of this chromium in D2 steel is tied up in carbides, limiting its availability for promoting passivation and corrosion resistance. 

Consequently, S35VN benefits from its higher chromium content specifically in solution, as well as the presence of molybdenum and niobium for enhanced passivation. 

Furthermore, the powder metallurgy process used in producing S35VN results in a more homogeneous and refined microstructure, minimizing potential sites for localized corrosion.

Overall, the premium stainless powder metallurgy S35VN steel outperforms the conventional high-chromium tool steel D2 in terms of corrosion resistance capabilities.

Ease of sharpening

When it comes to sharpening and grinding, D2 steel has a slight advantage over S35VN steel in terms of ease of material removal.

S35VN contains hard vanadium and niobium carbides, which make it somewhat more difficult to grind, machine, and polish compared to D2 steel steels without these ultra-hard carbide types.

In contrast, D2 steel relies primarily on chromium carbides for its wear resistance, which are not as hard as the vanadium and niobium carbides found in S35VN.

D2 is expected to be slightly less abrasion-resistant during sharpening and grinding processes compared to S35VN.

While the refined microstructure of the powder metallurgy S35VN helps mitigate some of the challenges associated with its hard carbides, the absence of such carbide types in D2 gives it an inherent advantage in terms of ease of material removal.

Overall, both steels require robust abrasives like cubic boron nitride for efficient sharpening, but D2 is considered somewhat easier to sharpen and grind compared to the premium powder metallurgy stainless steel S35VN.

Final Thoughts on S35VN vs D2

In my experience working with various premium knife steels, I’ve developed a strong appreciation for both S35VN and D2.

S35VN steel impressive combination of toughness, ease of sharpening, and excellent corrosion resistance make it a compelling choice that I would readily recommend to most knife users.

The refined powder metallurgy microstructure and strategic alloy additions in S35VN result in a well-rounded performance that excels across multiple criteria.

However, I must admit to having a particular attachment to one of my D2 steel knives, as its exceptional edge retention has proven to be truly remarkable.

Despite its relatively coarse microstructure and semi-stainless nature, D2’s high chromium content and hard carbides enable it to maintain a keen edge for extended periods.

While S35VN may be the more versatile and user-friendly option overall, there’s something deeply satisfying about the rugged simplicity and sheer edge-holding tenacity of a well-made D2 blade.

Ultimately, both steels have their strengths, and my appreciation for each stems from their unique characteristics and the specific applications where they truly shine.