AUS8 Steel - Stainless Steel

Also known as 8A, A8 or more informally as "Molybdenum Steel," AUS8 knives are easily accessible to households due to their affordable prices, and we carry them through our 8A-N series. It's also rust-resistant, easy to sharpen and most importantly - sharp! This blog will go into further details about this price-conscious stainless steel to help you decide if it's right for you!

AUS8 Stainless Steel - Highly Valued by Professionals and Households

AUS8 Stainless Steel is a steel that is quite resistant to rust, maintains a certain degree of sharpness and is easy to sharpen as well as handle in the kitchen.

There is actually no steel formally named "Molybdenum Steel," and most of the "Molybdenum Steel," "Molybdenum-Vanadium Steel," "MV Steel" or even "INOX Steel" materials in circulation are infact AUS8 steels. We say most because there are exceptions - not all manufacturers disclose their steel names, so this is best to interpret more as a light, general rule.

There are many reasons why manufacturers may use these names over AUS8, but the most crucial reason is that steel material alone does not dictate the quality of a final product. Rather, the manufacturing process itself indicates much of the quality behind a steel and the knives used to make it, as well as their performance. So, these names can sometimes be used to avoid comparisons between AUS8 steels and knives from different manufacturers based on the steel alone.

Any steel with molybdenum in it can be referred to as "Molybdenum Steel," however when rarer or more expensive materials are also part of the composition, different names are often used.


The Impact of "Molybdenum"

About 30-40 years ago, stainless steel knives were primarily made of steel with a carbon content of around 0.6%, such as AUS6 or 420J2 steels. As you will see later in the composition table, AUS6 does not contain any added molybdenum (Mo) or vanadium (V).

During an era when carbon content was the sole factor used to estimate the performance of blades, the introduction of these two elements significantly altered the general impression of stainless steel. It improved the toughness and edge retention to such a degree that people started seeing stainless steel significantly differently compared to their carbon steel counterparts.

This had a huge impact at a time when carbon steel was so widespread that people had the impression that "stainless steel knives are dull and can't be sharpened.''

With a 13% chromium (Cr) content, which helps prevent rusting, and the added benefit of improved sharpness, the inclusion of molybdenum (and vanadium) was highlighted as a unique point for these knives. Knife manufacturers then adopted terms like "Molybdenum steel" and "INOX steel" and marketed them as "stainless steel knives with excellent sharpness."

Steel Mapping Comparison

Steel material is crucial for indicating a knife's initial performance (amongst many other things related to craftsman ability and more). Below are some comparisons to give you some understanding showing what a particular step of the process does in terms of impacting sharpness, balance and maintainability.

Steel Material Heat Treatment/Forging Edge Sharpening Handle Attachment

Sharpness

Balance

Maintainability

Steel Material Heat + Forging Making Edges Handle Attach.

Sharp.

Bal.

Maint.

There’s three key pointers in the above chart to focus on.

  • Steel Material has a large impact on sharpness and maintainability (ease of sharpening and resistance to rust).

  • Apart from sharpness, heat treatment and the sharpening process in knife creation also have a large impact on sharpness.

  • Measuring a knife’s strengths is more than just its sharpness. Balance and maintainability also need to be considered.

Based on the above steel mapping chart, AUS8 Steel falls in this position on the graph below:

When looking at a comparison chart like this which places AUS8 near the quick sharpness loss section, it may not seem like an outstanding steel to make a blade with. However, having a certain level of hardness and being easy to process are significant advantages for the knife manufacturer. For example, this makes it easier for craftsmen to create high-quality blades which in itself is a massive advantage, as this keeps prices down.

Among stainless steels, AUS8 is known for being relatively easy to sharpen on a whetstone, a well-kept secret of its popularity. Naturally, a sharpened AUS8 blade often outperforms a Powdered High-Speed Steel blade that hasn't been sharpened or maintained for a while. Having a blade that is easy to sharpen also means the blade itself is likely to be used for a longer time, as it's a much simpler process to bring it back to maximum performance.

This can make AUS8 a great steel for beginners and experts alike!

Easy to sharpen and bring back to maximum performance!


Composition Comparison

Let’s look at the tables below and explore the composition of AUS8 Steel more deeply.

Maker Steel Name Carbon Silicon Cobalt

Effect

Hard.

Hard. (⅒ Carbon)
Oxygen Rem.

Decarb Pvnt.
Tough.
Wear Res.

Listed Value

Average

Max

Average

Aichi Steel

AUS6

0.6

1

Aichi Steel

AUS8

0.75

1

Aichi Steel

AUS10

1.025

1

Takefu Special Steel

VG1

1

0.5

Masahiro x Daido Steel

MBS-26

0.9

1

0.45

Hitachi Metals

Silver Steel #3

1.025

0.35

Takefu Special Steel

VG5

0.7

0.5

1.4

Takefu Special Steel

VG10

1

0.35

1.55

Bohler-Uddeholm

AEB-L

0.67

0.4

Maker Steel Name Phos. Sulfur Mang.

Effect

Embrittlement

Embrittlement

Sulfur Rmvl.
Tough.

Listed Value

Max

Max

Average

Aichi Steel

AUS6

0.04

0.03

1

Aichi Steel

AUS8

0.04

0.03

0.5

Aichi Steel

AUS10

0.04

0.03

0.5

Takefu Special Steel

VG1

0.03

0.03

0.5

Masahiro x Daido Steel

MBS-26

0.04

0.03

0.45

Hitachi Metals

Silver Steel #3

0.03

0.02

0.8

Takefu Special Steel

VG5

0.03

0.03

0.5

Takefu Special Steel

VG10

0.03

0.03

0.4

Bohler-Uddeholm

AEB-L

0.025

0.015

0.6

Maker Steel Name Molyb. Vanad. Nickel

Effect

Wear Res.
Anti-Corrosion
Tough.

Wear Res.
Decarb Pvnt.

Tough.

Listed Value

Average

Average

Average

Aichi Steel

AUS6

0.49

Aichi Steel

AUS8

0.2

0.175

0.49

Aichi Steel

AUS10

0.205

0.185

0.49

Takefu Special Steel

VG1

0.3

0.25

Masahiro x Daido Steel

MBS-26

0.45

0.1

0.3

Hitachi Metals

Silver Steel #3

Takefu Special Steel

VG5

0.3

0.1

0.25

Takefu Special Steel

VG10

1

0.3

0.25

Bohler-Uddeholm

AEB-L

Maker Steel Name Tung. Copper Chrom.

Effect

Wear Res.

Antibac.
Embrittlement

Anti-Corrosion

Listed Value

Average

Max

Average

Aichi Steel

AUS6

13.75

Aichi Steel

AUS8

13.75

Aichi Steel

AUS10

13.75

Takefu Special Steel

VG1

14

Masahiro x Daido Steel

MBS-26

0.15

13.75

Hitachi Metals

Silver Steel #3

13.75

Takefu Special Steel

VG5

0.25

14

Takefu Special Steel

VG10

0.25

15

Bohler-Uddeholm

AEB-L

13

Manufacturer Steel Name Carbon Silicon Cobalt Phosphorus Sulfur Manganese

Effect of Material

Hardness

Hardness (⅒ of Carbon)
Oxygen Removal

Decarburization Prevention
Toughness
Wear Resistance

Embrittlement

Embrittlement

Sulfur Removal
Toughness

Listed Value

Average

Maximum

Average

Maximum

Maximum

Average

Aichi Steel

AUS6

0.6

1

0.04

0.03

1

Aichi Steel

AUS8

0.75

1

0.04

0.03

0.5

Aichi Steel

AUS10

1.025

1

0.04

0.03

0.5

Takefu Special Steel

VG1

1

0.5

0.03

0.03

0.5

Masahiro x Daido Steel

MBS-26

0.9

1

0.45

0.04

0.03

0.45

Hitachi Metals

Silver Steel #3

1.025

0.35

0.03

0.02

0.8

Takefu Special Steel

VG5

0.7

0.5

1.4

0.03

0.03

0.5

Takefu Special Steel

VG10

1

0.35

1.55

0.03

0.03

0.4

Bohler-Uddeholm

AEB-L

0.67

0.4

0.025

0.015

0.6

Manufacturer Steel Name Molybdenum Vanadium Nickel Tungsten Copper Chromium Hardness Rockwell Counter (HRC)

Effect of Material

Wear Resistance
Anti-Corrosion
Toughness

Wear Resistance
Decarburization Prevention

Toughness

Wear Resistance

Antibacterial Effects
Embrittlement

Anti-Corrosion

Changes in the quenching process

Listed Value

Average

Average

Average

Average

Maximum

Average

Aichi Steel

AUS6

0.49

13.75

55.5

Aichi Steel

AUS8

0.2

0.175

0.49

13.75

57.5

Aichi Steel

AUS10

0.205

0.185

0.49

13.75

59.5

Takefu Special Steel

VG1

0.3

0.25

14

60

Masahiro x Daido Steel

MBS-26

0.45

0.1

0.3

0.15

13.75

58.5

Hitachi Metals

Silver Steel #3

13.75

60

Takefu Special Steel

VG5

0.3

0.1

0.25

0.25

14

59

Takefu Special Steel

VG10

0.1

0.3

0.25

0.25

15

60

Bohler-Uddeholm

AEB-L

13

59

The hardness is rated at 57.5, which is slightly lower compared to other high-end stainless steels like Silver Steel #3, VG1 or VG10 (all which measure at 60). However, with the addition of molybdenum and vanadium, toughness and wear resistance are improved.

Due to those additions however, for those more used to or familiar with carbon steels like White Steel, you may experience a slight slip when sharpening on a whetstone in comparison.


Does AUS8 Steel Rust, Even Though It's Stainless Steel?

By definition, stainless steel contains plenty of chromium and is supposed to be rust-resistant, but depending on the storage conditions, such as contact with other metals and rusty items, or use of a dishwasher, rust may appear. They are rust-resistant, but they are not rust-proof.

On top of this, the rust does not turn pale and brown like you see in White Steel, but instead rusts in spots, creating small holes. Be careful and if there is any rust, remove it with a cleanser or the back of a sponge and store it in a dark, dry place. See more tips about knife care here!


Is AUS8 Overexagerrated in Marketing?

While AUS8 is indeed an excellent material, expressions referring to it like "an innovative material, Molybdenum steel used in Japanese production" may seem a bit exaggerated from the perspective of knife shops. The statement isn't false, it was an innovative material - however that was the case 30-40 years ago.

This is because more premium materials than Molybdenum Steel, such as VG10 or Powdered High-Speed steels, have become widespread and popular.

Especially with some crowdfunding projects and products associated with copywriters or marketing specialists, there is a tendency to excessively praise AUS8 steel. While it's certainly versatile and user-friendly with people and companies that use it professionally, it feels more accurate to describe it as a "relatively affordable material for professional use."

Conclusion

Let’s quickly recap the four key points of AUS8 Steel here

  • AUS8 steel defies the common belief that stainless steel cannot be sharp.

  • It possesses a well-balanced combination of being rust-resistant, having excellent sharpness, and being easy to sharpen.

  • Although it is stainless steel, caution is required to prevent rust.

  • Beware of overhype in marketing, and keep an eye out for its many alternative names.

AUS8 is a great choice for newcomers to Japanese knives, and well worth considering. Have a chat with us online or in-store and feel free to ask more about it to find out if it's most appropriate for your needs.


Take a look at some of our AUS8 Steel knives!