New.Knife.Day

Home Categories Steel Comparisons Steels

100

POINTS

1 ROLL

AUS 6 vs 420 Knife Steel Comparison

AUS-6 vs. 420 Steel: A Comprehensive Comparison for Knife Enthusiasts

When it comes to choosing a knife, steel selection is one of the most important factors to consider. AUS-6 and 420 are both well-known stainless steels often found in budget-friendly knives, kitchen cutlery, and entry-level outdoor blades. In this blog post, we’ll dive into the composition, heat treatment, performance characteristics, real-world usage, and more, to give you a well-rounded perspective on these two steels. Whether you’re a collector, an outdoors enthusiast, or simply looking to expand your knowledge about knife steels, read on for a thorough comparison.

1. Overview of AUS-6 Steel

1.1 Chemical Composition

AUS-6 is a Japanese stainless steel with roughly 0.60% carbon. It typically contains:

Carbon (~0.60%): Contributes to hardness and edge retention.
Chromium (~13.5–14%): Provides corrosion resistance.
Manganese (~1%): Aids in hardenability and helps with wear resistance.
Nickel (~0.5%) and Vanadium (~0.2%): Help refine grain structure and contribute to better strength and toughness.
Silicon (~1%): Enhances strength and helps deoxidize the steel during manufacturing.

Overall, AUS-6 is designed to offer very good corrosion resistance and good toughness, though it trades off in edge retention, which is on the lower side. However, it is highly regarded for its excellent ease of sharpening.

1.2 Typical Hardness (Rockwell C) Ranges and Practical Implication

Typical Hardness Range: ~55–58 HRC

This range provides enough hardness to hold an edge for light or moderate use. It’s not so hard that it becomes brittle or overly difficult to sharpen. AUS-6’s mid-range hardness allows for good toughness, and means regular blade touch-ups will be quick and simple.

1.3 Key Performance Characteristics

Corrosion Resistance: Very good (adequate for humid or marine environments).
Toughness: Good, suitable for general or light-duty tasks.
Edge Retention: On the lower end—edges will wear more quickly under heavy use.
Ease of Sharpening: Excellent—very forgiving for beginners.

1.4 Heat-Treatment Nuances and Forging

AUS-6 responds well to conventional heat-treating processes. It typically does not require extraordinary steps; however, manufacturers must still control temperatures carefully to avoid adversely affecting hardness or toughness. As a stainless steel, AUS-6 is less prone to warping or cracking than higher-carbon tool steels, but consistent tempering remains crucial for the best balance of hardness and toughness.

1.5 Patina Formation and Protective Coatings

AUS-6 is stainless, so it is unlikely to form a patina under normal conditions. Its chromium content effectively resists rust and staining. Additional protective coatings are rarely applied, given its inherently robust corrosion resistance.

2. Overview of 420 Steel

2.1 Chemical Composition

420 stainless steel often has 0.15–0.45% carbon, but a common benchmark figure is around 0.38%. (Keep in mind that variants like 420J2 or 420HC will vary slightly.) In general, 420 steel contains:

Carbon (~0.38%): Contributes modestly to hardness.
Chromium (~13%–14%): Key to corrosion resistance.
Manganese (~0.5%), Silicon (~0.5–0.75%), and Vanadium (~0.15–0.3%): Aid in strength and wear characteristics, though the effect is modest due to the relatively lower carbon content.

Its chemical makeup allows 420 to achieve very good corrosion resistance, and it maintains decent toughness. The trade-off of lower carbon, however, is reduced hardness potential, often yielding lower edge retention compared to steels with higher carbon content.

2.2 Typical Hardness (Rockwell C) Ranges and Practical Implication

Typical Hardness Range: ~50–54 HRC

420 steel is often found at the lower end of the hardness spectrum. This offers excellent toughness and easy sharpening, but it won’t hold an edge as long as higher carbon or more premium stainless steels.

2.3 Key Performance Characteristics

Corrosion Resistance: Very good (especially in wet or marine conditions).
Toughness: Good; resistant to chipping and breaking.
Edge Retention: Lower—adequate for light-duty tasks.
Ease of Sharpening: Excellent; even basic sharpening equipment can restore a working edge fast.

2.4 Heat-Treatment Nuances and Forging

420 is well-known for ease of heat treatment. Manufacturers have used 420 for cutlery, surgical instruments, and more because it’s quite forgiving during production. Variants like 420HC, with slightly higher carbon content, can achieve hardness levels on par with or exceeding AUS-6 if treated properly.

2.5 Patina Formation and Protective Coatings

Like AUS-6, 420 is a stainless steel and does not develop a patina in normal usage. The high chromium content minimizes rust and staining, so coatings are rarely necessary. Polished or bead-blasted finishes are common.

3. Detailed Alloy Element Effects

Here’s a brief overview of what each key element generally contributes:

Carbon: Increases hardness, edge retention, and tensile strength. AUS-6 (~0.60% C) can typically reach a slightly higher hardness than 420 (~0.38% C).
Chromium: Over ~10.5% confers “stainless” properties. Both steels contain around ~13%–14% chromium, giving them robust corrosion resistance.
Manganese: Aids in hardenability and strength. Both steels include moderate amounts.
Vanadium: Refines grain structure and can improve wear resistance. Both steels have small amounts.
Silicon: Improves strength and helps steel remain stable during manufacturing.

4. Side-by-Side Comparison

	AUS-6	420
Carbon Content	~0.60%	~0.38%
Typical Hardness (HRC)	~55–58	~50–54
Corrosion Resistance	Very good	Very good
Toughness	Good	Good
Edge Retention	Lower	Lower
Ease of Sharpening	Excellent	Excellent

Note: Some sources suggest that 420 may have slightly less edge retention overall than AUS-6, though it depends heavily on the specific heat treatment and variant (e.g., 420HC vs. standard 420).

5. Real-World Performance & Applications

5.1 Everyday Carry (EDC)

AUS-6: Great for light tasks—opening boxes, cutting rope, and everyday household use. Sharpening is straightforward, but you’ll need to do it more often if you cut abrasive materials regularly.
420: Similar performance for EDC purposes. The softer nature of 420 means very easy sharpening, with good corrosion resistance. Realistically, it won’t stay razor-sharp for prolonged periods if you use it heavily.

5.2 Bushcraft & Survival

AUS-6: Not commonly chosen for serious bushcraft due to lower edge retention, but it can handle basic camp chores (prep food, carve light kindling). If you don’t mind frequent touch-ups, it’s serviceable.
420: Often used in budget survival knives because of corrosion resistance and ease of manufacture. However, expect to resharpen if you’re doing extended or hard cutting tasks.

5.3 Kitchen Use

AUS-6: Popular in some entry-level Japanese kitchen knives. It resists staining, offers simple maintenance, and can be honed easily. Regular maintenance is necessary due to modest edge retention.
420: Common in budget kitchen knife sets or utensils. Quick to touch up with a honing rod, but dulls rapidly under heavy use.

5.4 Tactical or Defensive Applications

AUS-6: Lower edge retention makes it less common for tactical knives, though its corrosion resistance is beneficial in harsh climates.
420: Frequently seen in mass-produced tactical or utility blades, especially in budget lines. It’s cost-effective and corrosion-resistant, but not high-end in terms of cutting performance.

6. Ideal Uses of Each Steel and Why Choose Them

AUS-6:
- Ideal for users who want a stainless knife that’s extremely easy to sharpen.
- Good for light-duty kitchen tasks, EDC, or casual outdoor chores.
- Chosen by those who value a slightly higher hardness range (and potentially slightly better edge retention than standard 420) at a low cost.
420:
- A go-to choice for budget knives that must withstand moisture (fishing, marine, or general outdoor use).
- Very soft and easy to sharpen, making it good for those new to sharpening or who prioritize toughness over extended edge life.
- Often cheaper and extremely common in large-scale production knives.

7. Cost, Availability, and Maintenance

7.1 Cost

Both are considered affordable steels. AUS-6 may be marginally more expensive depending on the brand (often produced in Japan), while 420 is widely available and used worldwide.

7.2 Availability

It’s easy to find blades made from either steel in sporting goods stores and online marketplaces. 420, due to its use in everything from cutlery to surgical instruments, is extremely common. AUS-6 is frequently sourced from Japanese or other Asian manufacturers.

7.3 Maintenance

Both are stainless, so a simple wipe-down and, optionally, a bit of light oil generally suffice. You will need more frequent honing or sharpening with heavy use, especially if you use the knife on tough or abrasive materials—but both steels are very easy to sharpen, making maintenance quite painless.

8. Pros and Cons

8.1 AUS-6

Pros:

Very good corrosion resistance
Good toughness for general tasks
Extremely easy to sharpen
Affordable option for occasional users or home cooks

Cons:

Lower edge retention, requiring more frequent touch-ups
Not commonly used in higher-end knives
Less ideal for heavy chopping or high-volume cutting

8.2 420