Böhler M390 Microclean is a premium powder metallurgy stainless steel produced by Böhler-Uddeholm (Austria). It is widely regarded as one of the most balanced "super steels" in existence and has been the industry standard for high-end production and custom knives for over a decade.
Key Characteristics
Exceptional Edge Retention: Due to its high carbon and vanadium content, M390 holds a sharp edge for an incredibly long time. It is a top performer for daily cutting tasks.
Superior Corrosion Resistance: With 20% Chromium, it is extremely resistant to rust and staining. It is an ideal choice for premium knives that might be exposed to moisture or acidic materials.
High Wear Resistance: It resists abrasion very well, meaning the blade doesn't wear down easily even when cutting through tough, abrasive materials like thick cardboard.
Excellent Polishability: Unlike many other super steels, M390 can be ground and polished to a beautiful mirror finish, making it a favorite for "art knives" and high-end aesthetics.
Moderate Toughness: While it is strong, M390 can be somewhat brittle if heat-treated to its maximum hardness (60–62 HRC). It is more prone to micro-chipping than tougher steels like MagnaCut or CPM Cru-Wear.
Chemical Composition
Carbon (C): 1.90% (Very high for hardness and edge life)
Chromium (Cr): 20.00% (Provides elite rust resistance)
Vanadium (V): 4.00% (Creates hard carbides for wear resistance)
Molybdenum (Mo): 1.00%
Tungsten (W): 0.60%
Common Applications
High-End Production Knives: It is the "standard" for premium brands like Microtech, Zero Tolerance, Hinderer, and Benchmade (often as an upgrade).
Custom Knives: Favored by makers globally for its performance and prestige.
Industrial Components: Originally used for plastic injection molds that require extreme wear and corrosion resistance.
The "M390 Class"
As mentioned before, M390 has two direct American equivalents:
CPM-20CV (Crucible)
CTS-204P (Carpenter)
All three offer virtually identical performance in real-world use.
M390 vs. MagnaCut
M390 has slightly better wear resistance (stays sharp longer on soft materials) and polishes better.
MagnaCut is significantly tougher and even more corrosion resistant, making it the better choice for hard-use or saltwater environments.