S30V and S45VN are two Powder metallurgy knife steels developed by Crucible Industries, a leading manufacturer of specialty steels.
These two steels share a close relationship, with S45VN being an evolution in Crucible’s line of advanced CPM stainless steels, building upon the success of the earlier S30V and S35VN.
The primary distinction between CPM S30V and CPM S45VN lies in their alloy composition.
S45VN, introduced as an evolution of the popular S30V and S35VN steels, features a higher chromium content (16%) compared to CPM S30V (14%).
Additionally, CPM S45VN steel incorporates niobium and nitrogen additions.
This addition contribute to enhanced corrosion resistance, refined carbide structure, and slightly better toughness characteristics
S30V vs S45VN Steel At A Glance
| Property | CPM S30V Steel | CPM S45VN Steel |
|---|---|---|
| Composition | 1.45% C, 14% Cr, 4% V, 2% Mo | 1.48% C, 16% Cr, 3% V, 2% Mo, 0.5% Nb, 0.15% N |
| Attainable Hardness | Up to 64 HRC (Aim: 58-61 HRC) | Up to 64 HRC (Aim: 59-61 HRC) |
| Toughness | Average toughness | slightly better toughness than S30V |
| Edge Retention (CATRA) | Slightly Better edge retention than S45VN | Very Good edge retention |
| Corrosion Resistance | Very good corrosion resistance | Improved corrosion resistance over CPM S30V |
| Ease of Sharpening/Grindability | Moderately difficult to sharpen | Improved over CPM S30V |
Toughness
S45VN steel has slightly better toughness compared to S30V steel.
Crucible lists the transverse Charpy C-notch impact energy for S45VN as 11.0 ft-lbs, while for S30V, it is 10.0 ft-lbs.
This minor improvement in toughness in S45VN can be attributed to its modified compositin and the use of niobium, which helps refine the carbide structure and improve toughness.
The higher toughness of S45VN can translate to increased resistance to chipping or fracturing in knives, especially in thicker blades or when subjected to side loads or impact forces.
Tougher steels are better able to absorb and dissipate energy without catastrophic failure making them more suitable for demanding applications where the blade may encounter unexpected impacts.
It is worth noting that the toughness of both S30V and S45VN is relatively low, when compared to steels like 14C28N or even CPM 10V or CPM M4 steels
Hardness
There is no significant difference in the attainable hardness between S30V and S45VN steels.
Both steels can achieve hardness values up to around 64 HRC, with an aimed hardness range of 58-61 HRC for typical knife applications.
The datasheets for S30V and S45VN list very similar heat treatment response curves.
The data indicates that with the recommended austenitizing temperatures (1900-2000°F for both steels) and appropriate tempering temperatures, they can reach comparable maximum hardness levels.
Edge Retention
S30V steel has slightly better edge retention as compared to S45VN steel. Note that the difference is relatively small and gains will be realized when only both steel are heat treated at different HRCs.
Crucible datasheets indicate that S45VN and S30V have similar levels of edge retention, as measured by the CATRA (Cutlery & Allied Trades Research Association) test.
The CATRA test measures the relative wear resistance of a steel by counting the number of silica-impregnated cards it can cut.
S45VN steel is listed as having a CATRA value of 143% relative to 440C, while S30V steel is listed as 145%.
These values suggest that S45VN and S30V have comparable edge retention capabilities, with S30V having a slight edge over S45VN.
However, it’s important to note that the S45VN datasheet mentions that the CATRA value of 143% is based on market feedback, rather than direct testing.
In my independent testing I confirmed the exact edge retention performance of S30V is slightly better than that of S45VN steel especially in daily tasks..
Corrosion Resistance
S45VN and S30V exhibit comparable levels of corrosion resistance, although with a slight advantage for S45VN due to its higher chromium content.
These knife steels are both stainless steel with S45VN has 16% chromium, while S30V has 14% chromium.
The higher chromium content in S45VN knife steel promotes the formation of a more protective passive oxide layer, which enhances the steel resistance to corrosion.
Additionally, the niobium and nitrogen additions in S45VN help to reduce the formation of chromium carbides, leaving more free chromium available for corrosion resistance.
Corrosion testing using a 1% saltwater spray test, reveals that S45VN exhibits better resistance to corrosion than S30V and S35VN and is more on par with steels like M390, 20CV and 204P.
The slight improvement in corrosion resistance offered by S45VN may make it a more attractive choice for applications where the knife will be exposed to corrosive environments, such outdoor usage.
Ease of Sharpening
Crucible industries indicate that S45VN is much easier to grind than CPM S90V and easier to machine than CPM S30V.
The improved grindability and sharpening ease of S45VN can be attributed to its modified alloy, particularly the reduced vanadium content (3.0% V) compared to S30V (4.0% V).
Vanadium is known to form hard vanadium carbides, which can make steels more challenging to grind and sharpen due to the abrasion resistance of these carbides.
For knife users, the improved sharpening characteristics of S45VN can make it easier to maintain a sharp edge on the blade, thus requiring less effort and specialized equipment compared to S30V.
However, it’s important to note that while S45VN may be easier to sharpen than S30V, both steels are still considered relatively demanding to sharpen compared to lower-alloy stainless steels like 440C.
The presence of hard carbides in both S45VN and S30V will require the use of appropriate abrasives and sharpening techniques to achieve optimal results.
FInal Thoughts on S30V vs S45VN Steel
Having owned and used pocket knives and kitchen knives made with S30V steel, I can attest to its impressive edge retention and corrosion resistance, making it an excellent choice for many cutting applications.
However, S45VN represents a noteworthy improvement over S30V steel due to its balance in several key areas.
The increased chromium content, along with the additions of niobium and nitrogen, offer enhanced corrosion resistance.
S45VN maintains the excellent wear resistance and edge retention that S30V and S35VN Crucible’s powder metallurgy steels are known for.
One of the most significant advantages of S45VN steel is its improved ease of sharpening compared to S30V.
As someone with experience sharpening knives made from both steels, I can confirm that S45VN is indeed easier to sharpen.
Between S30V and S45VN, S45VN is a more user-friendly option for most knife applications, including EDC knives and kitchen knives.
The difference between S30V and S45VN in terms of toughness and resistance to edge chipping is relatively minor, with S45VN having a slight edge due to its refined carbide structure.
This makes S45VN an excellent choice for knives that may encounter demanding or abusive conditions without sacrificing edge retention or corrosion resistance.