N690 vs AUS 8 Knife Steel Comparison

N690 vs. AUS-8: Which Stainless Steel Is Best for Your Knife?

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Curious about N690 vs. AUS-8 stainless steels? Learn their compositions, hardness ranges, pros and cons, and real-world performance to choose the best blade for your needs.

Table of Contents

1. Introduction
2. Overview of N690
3. Overview of AUS-8
4. Typical Hardness & Practical Implications
5. Alloy Elements and Roles
6. Heat Treatment Nuances
7. Patina Formation & Coatings
8. Side-by-Side Performance Comparison
9. Ideal Uses & Reasons to Pick Each
10. Pros and Cons
11. Cost, Availability & Maintenance
12. Conclusion & Key Takeaways

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1. Introduction

When selecting a knife, the choice of blade steel can be more critical than the knife design itself. Factors such as edge retention, toughness under impact, and corrosion resistance all depend largely on the steel’s composition and heat treatment.

In this article, we compare Böhler N690 and AUS-8—two popular stainless steels frequently used in fixed blades, folding knives, and EDC designs. While each is known for corrosion resistance, they differ in edge-holding capability, toughness, cost, and ease of sharpening. Keep reading to discover which steel fits your usage and budget.

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2. Overview of N690

N690 (often labeled N690Co) is a stainless steel developed by Böhler in Austria. Sometimes called “Europe’s VG-10,” it offers a similar alloy profile to VG-10 and 154CM. Cobalt is a key part of N690’s composition, contributing to its hardness and wear resistance.

Key Properties:

• Good edge retention
• Good ease of sharpening (despite higher hardness potential)
• Very good corrosion resistance (about 17% chromium)
• Good toughness for a high-carbon stainless

Approximate Composition:

• Carbon (C): 1.08% – Increases hardness and edge retention.
• Chromium (Cr): 17.3% – Offers excellent corrosion resistance.
• Molybdenum (Mo): 1.1% – Boosts strength and corrosion resistance.
• Cobalt (Co): 1.5% – Enhances hardness and wear resistance synergy.
• Vanadium (V): 0.1% – Helps refine grain structure and improve wear resistance.

Typical Hardness (HRC): ~58–60
This allows for a reliable balance of edge retention and toughness, making N690 a favorite among custom and mid-tech makers for outdoor and kitchen applications alike.

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3. Overview of AUS-8

AUS-8 is a Japanese stainless steel produced by Aichi Steel. Considered a mid-range option, it has been a staple for decades in budget-friendly to mid-priced knives. You’ll often see AUS-8 in popular brands like Cold Steel (historically), Ontario Knife Company, and others focusing on affordability.

Key Properties:

• Fair edge retention
• Very good ease of sharpening
• Excellent corrosion resistance (at least 13% chromium)
• Good toughness

Approximate Composition:

• Carbon (C): ~0.72% – Adequate for decent hardness without being brittle.
• Chromium (Cr): ~13.75% – Provides stainless properties.
• Molybdenum (Mo): 0.2% – Increases strength and corrosion resistance.
• Vanadium (V): 0.18% – Improves grain refinement and wear resistance.

Typical Hardness (HRC): ~57–59
In many production knives, AUS-8 is heat treated toward the mid-range of hardness, emphasizing toughness and ease of maintenance over long-edge retention.

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4. Typical Hardness & Practical Implications

Steel	Typical HRC Range	Implications
N690	58–60	Balanced hardness and toughness. With proper heat treatment, resists chipping and maintains an edge longer.
AUS-8	57–59	Slightly softer on average, making it easier to sharpen but with somewhat lesser edge retention compared to premium steels.

• N690 (58–60 HRC):
  Thanks to its higher carbon and cobalt content, N690 can achieve a slightly harder and more wear-resistant edge. It remains reasonably tough for outdoor and survival tasks.

• AUS-8 (57–59 HRC):
  AUS-8 is a catch-all steel that’s friendly to novice sharpeners. Because it resists rust and chips less easily, many budget or mid-range knives use it for EDC, hunting, or general-purpose tasks.

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5. Alloy Elements and Roles

Both N690 and AUS-8 rely on chromium for corrosion resistance and carbon for hardness. However, N690’s higher carbon and cobalt content generally equate to better wear resistance and edge-holding.

• Carbon (C):
  More carbon means higher achievable hardness. N690’s ~1.08% compares to AUS-8’s ~0.72%.
• Chromium (Cr):
  Both exceed 13% chromium, qualifying them as stainless and protecting against rust. N690’s 17% typically pushes it into “very good” corrosion resistance territory.
• Molybdenum (Mo):
  Present in both to bolster strength and corrosion protection.
• Cobalt (Co) (N690 only):
  Boosts hardness and overall performance—one reason N690 is considered a high-end stainless.
• Vanadium (V):
  Helps refine grain size, contributing to edge stability in both steels.

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6. Heat Treatment Nuances

• N690:

  • Straightforward to heat treat but does benefit from precise temperature control (especially for austenitizing).
  • Overheating can lead to undesirable grain growth.
  • Typically used via stock removal; forging is less common but possible with proper care.

• AUS-8:

  • Known for being forgiving.
  • Manufacturers can tweak protocols, which is why AUS-8’s hardness might range 57–59 HRC.
  • Warping or cracking is unlikely if standard stainless heat-treat guidelines are followed.

Both steels respond reliably to modern heat-treat methods, and neither is notoriously difficult to work with, which helps keep production costs reasonable (especially for AUS-8).

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7. Patina Formation & Coatings

• Patina Likelihood:
  Because both steels have chromium content above 13%, they rarely form a patina the way high-carbon steels (e.g., 1095) do. Under normal conditions, surfaces remain bright and rust-free with minimal care.

• Protective Coatings:
  Coatings like DLC (Diamond-Like Carbon) or PVD (Physical Vapor Deposition) are often not necessary for corrosion resistance but may be used for tactical or aesthetic reasons.

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8. Side-by-Side Performance Comparison

Attribute	N690	AUS-8
Corrosion Resistance	Very Good	Very Good
Toughness	Good	Good
Edge Retention	Good	Fair
Ease of Sharpening	Good	Very Good
Typical HRC Range	58–60	57–59
Availability/Cost	Mid to High	Budget/Mid

Real-World Scenarios

• Bushcraft & Survival:
  N690’s higher edge retention offers an advantage over long trips where sharpening might be infrequent. AUS-8’s easy sharpening makes it a good choice for budget-conscious users or those newer to bushcraft.

• Everyday Carry (EDC):
  AUS-8 is favored for simpler field maintenance. N690 can handle more abusive tasks before dulling, which is helpful if you rely on a single knife for multiple chores.

• Kitchen Applications:
  N690’s elevated chromium and cobalt content make it highly resistant to moisture and acidic foods, ideal for extended prep sessions. AUS-8 also works well in the kitchen but may require more frequent touch-ups.

• Tactical or Military:
  Both handle harsh conditions. N690 may retain its edge longer, but AUS-8’s straightforward field sharpening can be a lifesaver in high-adrenaline scenarios.

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9. Ideal Uses & Reasons to Pick Each

Why Pick N690?

• You value higher edge retention and can afford a step up in cost.
• You often encounter extreme or prolonged conditions where you can’t sharpen frequently (camping, survival, maritime).
• You prefer steels with a strong reputation in custom or mid-tech knives.
• You want a versatile steel that excels through varied tasks (culinary, bushcraft, EDC).

Why Pick AUS-8?

• You seek good performance at a budget-friendly price.
• You are new to sharpening or don’t mind sharpening more frequently.
• You plan to use the knife for everyday tasks or moderate outdoor activities.
• You want reliable stainless properties and a forgiving nature in case of incidental abuse.

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10. Pros and Cons

N690

Pros

• Excellent corrosion resistance (17%+ Cr)
• Good edge retention, aided by cobalt
• Fine-grained, can take a polished edge well
• Good blend of hardness and toughness

Cons

• More expensive than AUS-8 and not as widely mass-produced
• Slightly harder to sharpen compared to lower carbon steels (though still manageable)

AUS-8

Pros

• Very affordable and commonly available
• Excellent corrosion resistance
• Easy to sharpen, ideal for beginners or frequent sharpeners
• Good toughness for general-purpose usage

Cons

• Edge retention is moderate and can’t match higher-carbon or powder-metallurgy steels
• Often heat treated on the softer side, which limits ultimate wear resistance

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11. Cost, Availability & Maintenance

• Cost:

  • AUS-8: Typically found in budget to mid-priced knives. Its simpler composition and wide industrial use keep costs lower.
  • N690: Due to higher-end alloying (cobalt, higher carbon) and origins from Böhler’s European facilities, N690 often shows up in mid-range to premium knives.

• Availability:

  • AUS-8: Widely used by large-scale manufacturers, making it easy to find.
  • N690: Common among many European brands (e.g., Fox Knives, Extrema Ratio) and used by custom makers, though less ubiquitous in the budget knife market.

• Maintenance:

  • Both are “true stainless” with chromium content above 13%. Simple cleaning and occasional oiling (particularly on hinges/folders) will prevent corrosion.

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12. Conclusion & Key Takeaways

Choosing between N690 and AUS-8 depends on your priorities:

1. Performance vs. Budget:

   • N690 offers a higher potential hardness, better edge retention, and very good corrosion resistance.
   • AUS-8 is easier on the wallet and simpler to maintain for everyday tasks.

2. Sharpening Frequency vs. Edge Holding:

   • N690 goes longer before needing a refresh, but it can take slightly more effort to sharpen.
   • AUS-8 is extremely user-friendly and quick to sharpen—perfect for those learning sharpening techniques or who frequently re-sharpen.

3. Use Case:

   • N690 is well-suited for bushcraft, survival, and higher-end kitchen knives.
   • AUS-8 shines in general EDC, budget outdoor gear, or knives for casual users who want solid stainless performance without the premium price.

Both steels have stood the test of time, delivering reliable corrosion resistance and dependable service in wet or humid conditions. When deciding, also remember that heat treatment and blade geometry can significantly affect performance—sometimes more than the steel itself. Ultimately, your choice should align with how (and how often) you use your knife, and how much you’re willing to invest in premium edge retention.

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Further Reading & References

• Böhler Official Datasheets for N690
• Aichi Steel’s Composition Guidelines for AUS-8
• Comparative Analyses of VG-10, 154CM, and other mid/high-tier stainless steels

If you found this comparison helpful, feel free to share it with other knife enthusiasts. Happy knife shopping—and enjoy your new blade!