VG-10 vs M390: Which Steel Performs Better?

When we invest in a high-end kitchen knife, steel is always our top priority. The quality of the steel directly determines the knife’s performance limits. While there are many excellent premium steels on the market today, most enthusiasts would never overlook two standout options: VG-10 and M390.

In this article, we’ll dive deep into a detailed comparison of VG-10 and M390, examining their real-world performance through three key aspects:

• Chemical composition
• Heat treatment process
• Physical and mechanical properties

VG-10 Steel – Detailed Introduction

VG-10 is a premium stainless steel developed in the 1990s by Takefu Special Steel Co., Ltd. (Japan). Originally created for the high-end knife industry, it is renowned for its exceptional sharpness, corrosion resistance, and edge retention, earning the nickname “V-Gold 10” – symbolizing its “golden-class” performance.

This steel achieves high hardness after proper heat treatment while retaining good toughness, making it an ideal choice for professional kitchen knives, hunting knives, and high-quality scissors. VG-10 was designed to overcome the limitations of traditional carbon steels (prone to rust) and conventional stainless steels (lacking sharpness), offering the best of both worlds.

VG-10 Steel – Chemical Composition

VG-10 is carefully formulated to balance hardness, corrosion resistance, and edge retention. Typical composition (percentage by weight) is as follows:

• Carbon (C): 0.95–1.05% Provides high hardness and a razor-sharp edge, but excessive amounts can increase brittleness.
• Chromium (Cr): 14.5–15.5% The primary element for corrosion resistance, protecting the blade from rust in humid or wet environments.
• Molybdenum (Mo): 0.9–1.2% Enhances wear resistance and toughness, reducing edge wear during prolonged use.
• Vanadium (V): 0.1–0.3% Refines the grain structure, boosting overall strength and edge retention.
• Cobalt (Co): 1.3–1.5% Improves heat-treatment response and temper resistance, especially beneficial for blades with high-temperature coatings.
• Other elements:
  • Manganese (Mn) ≈ 0.5%
  • Silicon (Si) ≈ 0.6%
  • Phosphorus (P) and Sulfur (S) kept extremely low (<0.03%) for maximum purity and machinability.

These precise alloying elements distinguish VG-10 from standard stainless steels like AUS-8 (lower carbon content) and bring its performance close to some powder metallurgy steels, making it a favorite for high-end kitchen knives.

Heat Treatment Process

Heat treatment is the critical step that determines VG-10's performance, directly influencing its microstructure and final properties. The typical process includes:

Annealing: Heat to 800–850°C, then slow cool (cooling rate ≤25°C/hour) to soften the steel for easier machining and forming. This step relieves internal stresses and produces a pearlite or ferrite structure.

Quenching: Heat to 1050–1100°C (austenitizing temperature), hold, then rapidly cool, usually in oil (oil temperature ≈50°C) or air quenching. This forms a martensitic structure, dramatically increasing hardness, though it can introduce brittleness.
Tempering: Heat to 150–300°C for 1–2 hours, often repeated multiple times to relieve quenching stresses, improve toughness, and enhance dimensional stability. The addition of cobalt boosts temper resistance, allowing higher tempering temperatures without significant hardness loss—especially beneficial for coated blades.

After proper heat treatment, VG-10's microstructure consists primarily of a martensitic matrix with fine, evenly distributed carbides (such as chromium carbides and vanadium carbides), which significantly enhance wear resistance. Optimal heat treatment keeps hardness in the 58–62 HRC range, avoiding excessive brittleness.

We must also consider sharpening techniques and the relationship between the user's skill level and the steel's difficulty. Most customers have average sharpening skills and often spend considerable time maintaining an M390 kitchen knife to keep it as sharp as factory condition—and they may not even achieve perfect results. VG-10 strikes an ideal balance in sharpening ease, edge retention, and corrosion resistance, with a very high margin for error.

Physical & Mechanical Properties

VG-10 delivers top-tier performance among knife steels:

• Hardness: 58–62 HRC High hardness ensures long-lasting sharpness, though it may chip under heavy impact.
• Edge Retention: Excellent High carbon and vanadium content allow the edge to resist dulling significantly longer when cutting fibrous foods (meat, vegetables), often lasting several times longer than standard steels.
• Corrosion Resistance: Outstanding High chromium provides strong rust resistance, ideal for kitchen or outdoor use. Still, clean promptly after exposure to strong acids (e.g., lemon juice).
• Toughness: Above average Good resistance to bending and impact, though less flexible than lower-hardness steels like AUS-10. Toughness (ability to resist chipping or breaking) is optimized via molybdenum and precise heat treatment.
• Wear Resistance: Very good Uniform carbide distribution reduces abrasion, especially during frequent or abrasive cutting.
• Density & Thermal Conductivity: ~7.8 g/cm³, moderate thermal conductivity Easy to machine and balance during forging.
• Other Properties: Strong fatigue resistance for prolonged use; may become slightly more brittle in extreme cold.

Overall, VG-10 offers an outstanding balance of sharpness, longevity, and ease of care, making it one of the most popular premium steels for high-end kitchen knives.

M390 Steel – Detailed Introduction

M390 is a premium powder metallurgy stainless steel developed by Böhler-Uddeholm in Austria, representing third-generation powder steel technology. Introduced in the late 1990s, it is widely used in high-end knives and industrial applications, renowned for its exceptional wear resistance, edge retention, and corrosion resistance.

Produced through advanced powder metallurgy, M390 eliminates the carbide segregation issues common in conventional cast steels, resulting in a highly uniform microstructure. This steel has become a favorite among knife enthusiasts and is often regarded as a true “super steel.” Its outstanding performance comes with some processing challenges due to its high alloy content.

M390 was engineered to achieve an optimal balance in high-carbon, high-alloy steels. It has near-identical equivalents such as CTS-204P (Carpenter) and Duratech 20CV (Crucible), which share very similar compositions and properties.

M390 Steel – Chemical Composition

M390 is engineered with a high-carbon, high-alloy formula to maximize wear resistance and hardness. Typical composition (percentage by weight) is as follows:

• Carbon (C): 1.9% Provides exceptional hardness and sharpness, though high levels increase brittleness risk.
• Chromium (Cr): 20% Significantly enhances corrosion resistance by forming a strong passivation layer to prevent rust.
• Molybdenum (Mo): 1% Improves wear resistance and toughness, while enhancing high-temperature stability.
• Vanadium (V): 4% Forms extremely hard carbides, dramatically boosting wear resistance and edge retention.
• Tungsten (W): 0.6% Refines carbide structure, increasing high-temperature hardness and wear resistance.
• Manganese (Mn): 0.3% Increases hardness, though excessive amounts can promote brittleness.
• Silicon (Si): 0.7% Improves strength and machinability.
• Phosphorus (P): ≤0.025% Kept very low to avoid brittleness.
• Sulfur (S): ≤0.010% Minimized to ensure purity and toughness.

These elements are evenly distributed through powder metallurgy, forming fine carbides (such as VC and WC) that are far more uniform than those in conventional steels.

Heat Treatment Process

M390 is highly sensitive to heat treatment, requiring precise control to achieve optimal performance. The typical process includes:

1. Annealing: Heat to 800–850°C, then slow cool in the furnace to soften the steel for machining. This produces a pearlite structure and relieves internal stresses.
2. Quenching: Heat to 1050–1150°C (austenitizing temperature), hold, then rapidly cool in a protective atmosphere (vacuum or nitrogen) at a minimum rate of -100°C/s. This forms a martensitic structure. Fast cooling is critical to avoid carbide coarsening; oil quenching or high-pressure gas quenching is recommended.
3. Tempering: Perform multiple tempers (usually 2–3 cycles) at 150–250°C for 1–2 hours each to relieve quenching stresses and enhance toughness. Tungsten and molybdenum provide excellent temper resistance, allowing higher tempering temperatures without significant hardness loss. Cryogenic treatment (–70°C to –196°C) is often used to convert retained austenite, further improving hardness and dimensional stability.

After proper heat treatment, M390's microstructure consists of a martensitic matrix with fine, uniformly distributed carbides, delivering exceptional wear resistance. Improper treatment can lead to increased brittleness or reduced hardness.

Physical & Mechanical Properties

M390 delivers outstanding performance among knife steels:

• Hardness: 60–62 HRC (up to 64 HRC depending on treatment) High hardness ensures exceptional edge retention and sharpness.
• Edge Retention: Exceptional High vanadium and fine carbides allow the edge to resist dulling for extended periods, even when cutting abrasive materials—often lasting months without re-sharpening.
• Corrosion Resistance: Outstanding 20% chromium provides excellent rust resistance, performing well in salt spray tests and humid or acidic environments.
• Toughness: Moderate High alloy content makes it relatively brittle; prone to chipping under lateral impact, though better than many ultra-hard steels.
• Wear Resistance: Top-tier Uniform carbide distribution offers superior abrasion resistance, far exceeding steels like D2 or 440C.
• Density & Thermal Conductivity: ~7.8 g/cm³, moderate thermal conductivity Facilitates machining and heat treatment.
• Other Properties: Strong fatigue resistance for prolonged use; high processing difficulty (requires diamond tools or specialized equipment).

Conclusion

M390 Steel Performs Better Overall Than VG-10, particularly in edge retention (sharpness longevity) and wear resistance, which are among the most critical performance indicators for high-end knives (such as kitchen knives). However, VG-10 has advantages in toughness and ease of sharpening, making it suitable for everyday home use.

Parameter Comparison Table