CPM 20CV steel produced by Crucible Industries and Elmax steel made by Bohler-Uddeholm are two high-performance powder metallurgy stainless steels designed for applications requiring hardness, wear resistance, and corrosion resistance.
A key difference between CPM 20CV and Elmax is that 20CV demonstrates better edge retention and durability under prolonged cutting usage.
Quantitative wear test data shows 20CV having a wear resistance up to 15% higher than Elmax after extended cutting. This gives 20CV a performance advantage in cutting applications requiring the very highest level of edge retention.
20CV vs Elmax at a Glance
| Property | CPM 20CV Steel | Elmax Steel |
|---|---|---|
| Composition | C 1.90%, Cr 20.0%, Mo 1.0% W 0.60%, V 4.0% | C 1.7%, Si 0.8%, Mn 0.3%, Cr 18.0%, Mo 1.0%, V 3.0% |
| Hardness | 55-59 HRC | 60-62 HRC |
| Edge Retention | Excellent, up to 15% better than Elmax | Very good |
| Toughness | Slightly better | Good, but lower than 20CV |
| Corrosion Resistance | Excellent, slightly better than Elmax | Excellent |
| Ease of Sharpening | More difficult due to high vanadium carbides | Easier than 20CV |
Hardness
In terms of Hardness, the main difference is that Elmax can reach a higher hardness range of 60-62HRC, while 20CV is more limited in maximum achievable hardness of 55-59 HRC.
When hardened and tempered appropriately, Elmax steel provides greater potential for wear resistance and edge retention due to its higher hardness.
Toughness
Toughness in steel is its ability to resist shock, breaking, or chipping on impact. CPM 20CV steel exhibits slightly higher toughness compared to Elmax steel.
Both Elmax and 20CV steels contain high amounts of chromium carbides and thus risk chipping, breaking, or cracking at higher hardness levels, 20CV provides slightly better toughness overall.
Edge Retention
CPM 20CV steel outperforms Elmax steel when it comes to edge retention and wear resistance.
The higher edge retention of CPM 20CV is achieved thanks to its superior alloy composition, which contains a very high amount of vanadium carbides.
These vanadium carbides are ideal for promoting edge retention and wear resistance. Comparatively, while Elmax steel also contains a high chromium content to improve wear resistance, it does not have the same level of vanadium as 20CV.
The large volume of vanadium carbides in 20CV gives it exceptional wear resistance and allows it to hold an edge significantly better than Elmax over time.
Testing shows that 20CV can retain its edge up to 180% longer compared to other knife steels like 440C.
So while Elmax does have good edge retention properties, CPM 20CV wins in terms of prolonged edge holding capability thanks to its optimized balance of alloying elements with an emphasis on vanadium carbide formation.
This makes 20CV the preferable choice over Elmax when edge retention and wear resistance is the primary concern.
Corrosion Resistance
Both Elmax and 20CV steels provide excellent corrosion resistance due to the high chromium content in their composition.
However, 20CV contains 20% chromium, while Elmax has 18% chromium. This 2% higher chromium content gives 20CV slightly better corrosion resistance compared to Elmax.
The higher chromium in 20CV creates a more corrosion-resistant matrix that resists rusting and staining more than Elmax when exposed to moisture, acids, salts, and other corroding agents.
In direct comparison tests, 20CV knives perform marginally better than Elmax knives in terms of rust protection and stain resistance.
However, both blade steels resist corrosion superbly, with 20CV having just a small advantage over the already impressive corrosion resistance of Elmax.
For most applications, either steel will provide outstanding protection against rust and staining. But for environments with very high corrosion, 20CV’s extra 2% chromium gives it a slight edge
Ease of sharpening
When it comes to ease of sharpening, Elmax steel has a slight advantage over 20CV for knife applications.
Though both steels are made using powder metallurgy processes, which create a fine and uniform carbide distribution for good grindability, Elmax is slightly easier to sharpen.
This is due to Elmax steel’s lower total amount of carbides, specifically vanadium carbides, compared to 20CV steel.
The high vanadium carbide content (4%) in 20CV contributes to exceptional edge retention but also increases resistance while sharpening. Elmax, with a lower vanadium carbide content of 3%, offers less resistance on the stones.
For the knife sharpener, Elmax provides a moderately easier sharpening experience over 20CV, allowing knives to be brought to a razor edge with fewer stone passes.
However, both steels have excellent carbide distributions from powder metallurgy, giving them good grindability and sharpenability compared to conventional steels.
But ultimately, Elmax’s lower volume of hard vanadium carbides gives it a small advantage in terms of sharpening ease for knife applications.
Final thoughts on 20CV vs Elmax
CPM 20CV steel stands out when maximum edge retention and wear resistance are needed, thanks to its very high vanadium carbide content. This comes at the cost of being more difficult to sharpen.
On the other hand, Elmax can achieve a higher hardness range, giving it an advantage in potential wear resistance when properly heat treated. It also sharpens a bit easier than 20CV due to slightly fewer carbides.
In terms of corrosion resistance, both offer excellent protection, with 20CV having a slight advantage due to 2% more chromium in its composition.
When it comes to toughness, 20CV seems to resist chipping and cracking better than Elmax at high hardness levels.
Overall, I tend to prefer Elmax for many knife applications because it reaches higher achievable hardness levels for good wear resistance when heat treated properly.
And despite having great carbide volume and distribution for powdered steel, I find Elmax sharpens reasonably well without too much difficulty.
Yes, 20CV retains its edge noticeably longer, but I don’t mind occasionally sharpening my Elmax knife to restore its razor edge.
For uses where corrosion resistance is paramount, 20CV may be the better choice. But for most purposes, I think Elmax provides an optimal balance of hardness, edge retention, corrosion resistance, toughness, and sharpenability.
At least for my needs, Elmax hits the sweet spot while still being very capable in virtually every category. Both are excellent knife steels, but I usually lean towards Elmax as my personal favorite.