Steel is arguably the most important factor in determining the performance and longevity of a knife. One steel that has been growing in popularity lately is M390, an ultra-premium chromium stainless steel made by Bohler-Uddeholm.
But is M390 a good knife steel?
Yes, Bohler M390 is a good knife steel. It offers excellent edge retention, corrosion resistance, and high hardness.
In this article, we’ll take a close look at the properties and real-world performance of M390 steel and evaluate whether it lives up to the hype as one of the best all-around knife blade materials available today.
Table of Contents
What is Bohler M390 steel?
BÖHLER M390 MICROCLEAN is a very strong and durable steel produced by Bohler-Uddeholm. M390 steel is made using a process called “powder metallurgy” which allows it to have extremely high wear resistance. This means it is very hard and can keep a sharp edge for a long time without getting dull. It also has great corrosion resistance so it does not rust easily.
M390 belongs to a group of advanced steels called “3rd generation steels”. A 3rd generation steel is generally considered to have a minimum tensile strength and elongation product of 20 GPa percent. 3rd generation steels offer strength and the ability to shape the steel (ductility) of 2nd generation steels without the costs and joining problems. The automotive industry has studied these steels and found them to be excellent for making lighter but stronger car parts.
Chemical composition of M390 steel
| Element | Portion | Effect |
| Chrome | 20.0% | Improves wear resistance, heat resistance and scale resistance. It increases tensile strength because it acts as a carbide former. Use of rust-proof or stainless steel, as it increases corrosion resistance from a mass proportion of 12.2%. Reduction in weldability. |
| Carbon | 1.9% | Increasing hardness and tensile strength. In larger quantities, increase in brittleness and reduction in forgeability and weldability. |
| Manganese | 0.3% | Improves hardness and tensile strength. |
| Molybdenum | 1.0% | Improves hardenability, tensile strength and weldability. Reduction in forgeability and ductility. |
| Silicon | 0.7% | Improves strength. |
| Vanadium | 4.0% | Increasing hardness, increasing wear resistance and improving tempering resistance. |
| Tungsten | 0.7% | Increase in heat strength, tempering resistance and wear resistance at high temperatures up to red heat. |
Hardness of Bohler M390 steel
Bohler states the hardness of M390 to be 60-62 HRC, placing it in the upper mid-range on par with many well-known and popular steels from 440C to CTS-XHP to ELMAX and CPM 110V.
Bohler M390 steel properties
High wear resistance
M390 is overwear resistant. This means a knife made of Bohler M390 is very tough and durable, and can maintain sharpness for a long time, qualifying it as a premium knife.
High corrosion resistance
Anyone who has ever been hunting or camping knows that a knife here will get wet in one way or another or get exposed to moisture. Whether when cutting up the hunted animal or preparing dishes with acidic fruits such as citrus fruits. It doesn’t matter, the steel must have a high level of corrosion resistance in order not to rust or to make the knife easier to care for.
High-gloss polishability
A highly polished steel means a highly polished knife. In practical use, it is probably of less importance, unless you are a knife collector. On the other hand, M390 steel offers just that, and a highly polished knife looks nice too, doesn’t it?
High toughness
High-strength steel gives a knife the toughness it needs for everyday use, especially in camping and survival situations. You can always use a tough knife – as a can opener, a substitute for a small hammer, or other jobs like “batoning” (splitting wood with a knife as an axe substitute and a club to drive it in) when you don’t have the right tool on hand.
Machinability
According to BÖHLER, M390 is perfectly easy to grind – provided you have a belt grinder or similar. However, this does not mean that it can be easily sharpened with a conventional grindstone – if at all, it requires a diamond grindstone and even then it is not “just” sharpened.
Always remember, whether professional or amateur, the rule is: high edge retention = high strength = hard(er) to sharpen – THIS applies to all steels!
Bohler M390 in comparison with other popular knife steels
In terms of maximum hardness, M390 is in the same league as CPM 20CV or CPM S110V (61 HRC). But hardness alone, as we know, is not everything. Therefore, here are some rough comparative values with competing knife steels:
M390 vs CPM 20CV steel
| Criteria | Bohler M390 | CPM 20CV |
| Edge retention | 8/10 | 8/10 |
| Simplicity of sharpening | 5/10 | 5/10 |
| Corrosion resistance | 8/10 | 8/10 |
| Toughness | 6/10 | 6/10 |
As you can see, CPM 20CV is a steel with almost identical properties to M390. Both steels are high-quality steels with high edge retention, high corrosion resistance and high toughness, but are somewhat more demanding to sharpen.
M390 vs CPM M4 steel
| Criteria | Bohler M390 | CPM M4 |
| Edge retention | 8/10 | 8/10 |
| Simplicity of sharpening | 5/10 | 3/10 |
| Corrosion resistance | 8/10 | 3/10 |
| Toughness | 6/10 | 6/10 |
CPM M4 achieves the same edge retention strength and toughness as M390, but CPM M4 is a high-carbon steel with low corrosion resistance.
M390 steel vs CPM S90V
| Criteria | Bohler M390 | CPM S90V |
| Edge retention | 8/10 | 8/10 |
| Simplicity of sharpening | 5/10 | 5/10 |
| Corrosion resistance | 8/10 | 7/10 |
| Toughness | 6/10 | 2/10 |
CPM S90V offers the same or very similar edge retention values compared to Böhler M390, but has lower toughness, lower corrosion resistance and is more difficult to sharpen.
M390 steel vs CPM S110V
| Criteria | Bohler M390 | CPM S110V |
| Edge retention | 8/10 | 8/10 |
| Simplicity of sharpening | 5/10 | 3/10 |
| Corrosion resistance | 8/10 | 6/10 |
| Toughness | 6/10 | 3/10 |
CPM S110V reaches the same level as Bohler M390 in terms of sharpness and corrosion resistance but with lower toughness.
M390 vs CPM S35VN steel
| Criteria | Bohler M390 | CPM S35VN |
| Edge retention | 8/10 | 6/10 |
| Simplicity of sharpening | 5/10 | 6/10 |
| Corrosion resistance | 8/10 | 7/10 |
| Toughness | 6/10 | 8/10 |
M390 only slightly outperforms CPM S35VN in all aspects. So if you can’t afford M390, just buy CPM S35VN!
How good is Bohler M390 steel?
Bohler M390 steel is very, very good quality steel, considered one of the best available for knives and tools. Here are some reasons why:
- Exceptional Edge Retention: It stays sharper for much longer than most other steels when used to cut things. Maintains a razor-sharp edge through lots of use.
- High Wear Resistance: It is extremely hard, over 60 on the Rockwell scale. This hardness allows it to resist friction, abrasion, and wear much longer before any damage occurs.
- Great Toughness: Though very hard, it has some flexibility and impact resistance instead of being brittle. This is important for knives that may hit bone.
- Excellent Corrosion Resistance: Due to the high chromium content it can resist rust and discoloration even in very humid or salty environments.
- Holds a Fine Edge: It can be sharpened to an extremely fine, sharp edge for precise cutting tasks. The fine grain size helps.
Is M390 a stainless steel?
Yes, M390 is a stainless steel. It is a high-performance powder metallurgy stainless steel known for its excellent corrosion resistance, high hardness, and superior edge retention. M390 is classified as a stainless steel primarily due to its composition, which includes a significant amount of chromium. Chromium is a key element in stainless steels as it forms a protective oxide layer on the surface of the steel, providing excellent resistance to corrosion and rust.
In the case of M390, its composition includes chromium, molybdenum, vanadium, and other alloying elements (see composition above), contributing to its exceptional corrosion resistance and overall durability.
Conclusion: Is M390 a good knife steel
Bohler M390 stands out as a superior, premium steel with diverse applications, ensuring long-lasting enjoyment. However, it’s not recommended for use in extremely corrosive environments or applications, such as maritime settings. In such cases, H1 or LC200N are excellent alternatives.
If you are not experienced enough, be cautious about sharpening the M390 knife blade. If you are on a tight budget, CPM S35VN offers nearly identical properties at a more affordable cost.
