M390 belongs to the third generation of powder steel, created by steel giant Böhler-Uddeholm (Sweden).
A "hidden giant" in the steel industry, Böhler specializes in producing top-tier steels that drive knife enthusiasts wild. M390, Elmax, N690, and other legendary steels are all from Böhler, exclusively for the high-end market.
Their products are used in aerospace and medical devices; ordinary steel mills are like roadside stalls compared to them.
Traditional steelmaking produces coarse crystals (like a large batch of vegetables), resulting in uneven performance.
Böhler's core technology, however, is gas atomization powder metallurgy steel, which sprays molten steel into nanoscale particles and sintersulates it under high pressure, giving it performance that far surpasses that of ordinary steels (such as 1095 and D2).
M390 uses a combination of spray-drying powder casting and high-pressure sintering, further enhanced by vanadium carbide and chromium compounds. Its wear resistance is approximately equal to S90V, three times that of 440C (in my opinion), and it has extremely strong rust resistance (thanks to its 20% chromium content). The alloy composition is: 20% chromium, 1.9% carbon, and 4% vanadium.
The M390 also has fatal flaws. Flaw
1: It's expensive; the same billet of M390 costs three times as much as D2. Flaw
2: It's difficult to sharpen. While ordinary knives can be easily sharpened with sintered or natural whetstones, the M390's extremely high wear resistance requires considerable effort even with a diamond whetstone. Flaw
3: Extremely rough use (such as chopping iron) may cause chipping; it lacks flexibility. These three main drawbacks make the M390 more suitable for compact and powerful tools, such as folding knives and short hunting knives, with performance limitations restricting its maximum length (I personally recommend keeping it under 40 cm).
