AEB-L, originally produced by Uddeholm as a razor and scalpel steel, has found widespread use in the custom knife community due to its excellent balance of toughness, and corrosion resistance.
In contrast, M390 is a premium stainless steel, created by Böhler and also produced as 20CV by Crucible and 204P by Carpenter, known for its exceptional wear resistance.
AEB-L stainless steel, achieves its impressive combination of qualities through a relatively low carbide volume and finely distributed carbide structure.
M390, on the other hand, is a martensitic chromium stainless steel produced via powder metallurgy, endowing it with a much higher overall carbide content.
The Key difference between these steels is AEB-L exhibits significantly higher toughness than M390, over twice the impact energy in testing, due to its smaller, more evenly dispersed carbides.
AEB-L Steel vs M390 At A Glance
| Property | AEB-L Steel | M390 Steel |
|---|---|---|
| Toughness | Higher toughness, over twice of M390 | Lower toughness compared to AEB-L |
| Edge Retention / Wear Resistance | Good wear resistance, but slightly lower than M390 | Exceptional wear resistance and edge retention, outperforming AEB-L |
| Corrosion Resistance | Good corrosion resistance, but lower than M390 | Superior corrosion resistance compared to AEB-L due to higher chromium content |
| Ease of Sharpening | Easier to grind, polish, and sharpen | More challenging to sharpen |
| Hardness | High hardness levels, up to 64 HRC | High hardness levels, up to 64 HRC |
Hardness
AEB-L can be heat-treated to reach high hardness levels, around 63-64 HRc, by using higher austenitizing temperatures combined with cryogenic treatments.
M390 has a higher overall carbide content, including a significant fraction of hard chromium carbides, which limits its maximum hardness to around 64 HRc.
Hardness is a critical factor in blade steels as it directly affects other factors like toughness, edge retention, and ease of sharpening
Toughness
AEB-L exhibits substantially higher toughness than M390, over twice the impact energy in testing.
This superior toughness in AEB-L is attributed to its finer, lower volume carbide structure compared to the coarser, higher carbide content of M390.
The small, evenly distributed carbides in AEB-L allow it to maintain excellent toughness even at high hardness levels, ideal for thin, acute-angled knife edges that require both strength and impact resistance.
In contrast, the higher carbide content and larger carbide size in M390 limits its toughness, though it provides exceptional wear resistance.
This tradeoff means M390 is better suited for knives with more robust, obtuse edge geometries that prioritize extreme edge retention over maximum toughness.
Overall, the superior toughness of AEB-L makes it an excellent choice for many demanding knife applications where both edge stability and impact resistance are crucial, while M390 is better optimized for maximum wear performance.
Edge Retention
M390 contains much higher total carbide content, including a significant fraction of hard chromium carbides, which gives it superior edge retention and wear resistance compared to AEB-L.
Testing has shown M390 maintains its edge far longer than AEB-L, making it well-suited for applications that demand extreme edge holding.
In contrast, AEB-L has a lower overall carbide volume, with a finer, more evenly distributed carbide structure.
While this results in slightly lower edge retention, it allows AEB-L to achieve an excellent balance of high hardness, good toughness, and reasonable wear resistance.
This makes AEB-L ideal for thin, acute-edged knives that prioritize keen, long-lasting cutting performance without sacrificing resilience to chipping or rolling.
Ease of Sharpening
The superior wear resistance of M390 comes at the cost of slightly diminished ease of sharpening relative to AEB-L, but the tradeoff is worthwhile for users who value maximum edge retention above all else.
AEB-L has a lower overall carbide content compared to M390, with a finer, more evenly distributed carbide structure.
This makes AEB-L steel easier to grind, polish, and sharpen for both knifemakers and end-users.
The softer carbides in AEB-L are less abrasive on sharpening stones and belts, allowing for quicker, more effortless edge maintenance.
In contrast, M390 stainless steel higher volume of chromium carbides makes it more challenging to sharpen, requiring more time and effort to restore the edge.
This trade-off is important for users who prioritize ease of sharpening and prefer a steel that can be readily honed to a razor’s edge.
While M390’s superior wear resistance means its edge lasts longer between sharpenings, AEB-L’s relative ease of sharpening makes it a more convenient choice for many knife owners.
The grindability advantage of AEB-L also benefits knifemakers, as it reduces manufacturing time and cost compared to steels like M390 with more abrasive carbide structures.
Corrosion Resistance
M390 is designed with a higher chromium content, around 20%, which gives it superior corrosion resistance compared to AEB-L’s 13% chromium.
Testing has shown M390 exhibits significantly less weight loss than AEB-L when exposed to corrosive environments like saltwater.
This enhanced corrosion resistance makes M390 a better choice for knives that will see use in harsh, humid, or marine environments where staining and pitting are a concern.
In contrast, while AEB-L maintains good general corrosion resistance, it is not as robust as M390 in the most demanding corrosive settings.
Overall, the better corrosion resistance of M390 is a key advantage, making it well-suited for outdoor knives, kitchen knives.
Final thoughts on AEB-L Steel vs M390
In my experience, the toughness of AEB-L steel is truly unparalleled. I have found it performs exceptionally well in fixed-blade knives used for demanding outdoor tasks, withstanding significant impacts without chipping or breaking.
On the other hand, M390 stands out for its exceptional edge retention, I’ve consistently had it maintaining its keen edge for more than twice as long as AEB-L in tasks like cardboard cutting.
The biggest caveat with M390, however, is that it requires more skill to sharpen when dull, as its hard carbide structure is less forgiving than the finer carbides in AEB-L.
The ease of sharpening is a significant advantage of AEB-L, making it a more user-friendly option for many.
I would generally recommend AEB-L steel for most knife applications due to its excellent balance of toughness, edge retention, and sharpening ease.
However, if maximum edge durability is the priority, then the trade-offs of M390 may be worthwhile, provided you are willing to invest the extra time and effort in sharpening