AUS 8 is a curious sounding alloy that you might come across when shopping for a new kitchen knife. Maybe you’ve heard nice things about this material. Or perhaps you are aware of the chemical composition but are unsure of how the blades will function in use.
An alloy in the Japanese produced AUS metal line called AUS 8 steel. Due to its high chromium concentration, AUS 8 steel is regarded as stainless. It has excellent corrosion resistance and a decent hardness rating thanks to its modest carbon content. The toughness and wear resistance of AUS 8 steel are improved by other components.
AUS 8 steel has properties that are similar to high-end carbon steel, but it is still as strong as stainless steel.
Considering an alloy’s composition might be perplexing because you never know what an elemental combination will result in. We will go over the elements that make up this stainless steel and explain how they each impact on how the metal behaves. In order to determine whether AUS 8 is a good material for knives, we will compare it to other varieties of steel.
What is AUS 8 Steel?
AUS 8 is a medium carbon stainless steel with high chromium content. It is often used in knives and other cutting tools because of its edge retention and corrosion resistance.
AUS 8 is known as Japanese steel which is produced by the Aichi Metal Company. Aichi provides premium metal to other manufacturers that produce kitchen knives. The AUS steel series consists of only one grade, AUS 8, along with AUS 1, AUS 4, AUS 6, and AUS 10. The carbon content increases as the number rises.
The exact composition of AUS 8 is shown below, but the primary distinction between these classes is that grades with higher numbers have a higher proportion of carbon.
What About AUS 8a Steel?
You might have heard of AUS 8a steel and be curious about how it varies from standard AUS 8. The only difference between 8a steel and other alloys is that 8a steel has received some type of heat treatment to increase its hardness or edge retention.
AUS 8a steel is a high-carbon, high-chromium stainless steel with a hardness of 58-60 HRC.
Composition of AUS 8 Steel
AUS 8 steel is a high-carbon, chromium alloy steel with a composition of 0.75% carbon, 0.9% chromium, 1.2% manganese, 1% molybdenum, and 0.04% phosphorus.
| Carbon (C): | 0.7-0.8% |
| Molybdenum (Mo): | 0.1-0.3% |
| Chromium (Cr): | 13-14.5% |
| Vanadium (V): | 0.1-0.25% |
| Manganese (Mn): | ≤ 0.5% |
| Silicon (Si): | ≤ 0.8% |
| Nickel (Ni): | ≤ 0.3% |
| Phosphorus (P): | ≤ 0.04% |
Iron (Fe) is the main material in this steel, as it is in all steel. Because AUS 8 steel has more than 10.5% chromium, it is an alloy of stainless steel. Stainless steel is known for both how shiny it looks and how it doesn’t rust. The chromium binds to the oxygen on the surface of the metal to stop iron oxide from forming.
Carbon is the other important part of making steel. If a steel alloy has more than 0.6% carbon by weight, it is called “high carbon.” This is true of AUS 8, so it is both a high-carbon steel alloy and a stainless steel alloy. Carbon is well-known for making steel harder and less likely to get scratched. On the other hand, steel can also become brittle when it has a lot of carbon in it.
Nickel and Molybdenum work with chromium to make it even more resistant to corrosion. Nickel also gives the AUS 8 alloy more toughness to make up for the fact that carbon makes it more brittle.
Manganese makes steel harder to work with. In the case of AUS 8a steel, this means that heat treatments can help the blade keep its edge longer and be less likely to wear down. The metal’s tensile strength goes up when silicon and vanadium are added to the alloy.
This is a pretty complicated mix, but each of the elements makes the metal slightly better in some way.
Is AUS 8 Stainless Steel Good for Kitchen knives?
AUS 8 is a good stainless steel for kitchen knives because it is durable and has a good balance of hardness and corrosion resistance.
Edge Retention and Hardness
As we’ve already said, AUS 8 steel is considered high-carbon steel because it has a lot of carbon in it. The hardness of this metal is about 58-59 on the Rockwell scale, which is good for a kitchen knife.
Because the steel is so hard, it keeps its edge well. Even though AUS 8 steel knives don’t hold an edge as well as high-end high-carbon knives, this is still a very good number.
So, you can chop on a cutting board for a long time without dulling the edge. Compared to other types of stainless steel, an AUS 8 knife’s edge will last longer, but it will still need to be sharpened every so often.
Toughness
If you look at how hard AUS 8 steel is, you might think that toughness is lost. This isn’t the case. AUS 8 is both high-carbon steel and stainless steel. The chromium and nickel in the alloy keep it from splitting or chipping.
An AUS 8 knife can take a lot of force before it breaks. This means that it is not a bad choice for people who have never used a knife before and might drop it. This toughness is also great for hunting knives and knives that fold up.
Corrosion Resistance
The better resistance to corrosion is a big reason to use an AUS 8 knife instead of a standard high-carbon knife. The main job of chromium in this alloy is to keep the blade’s surface from getting rusty. Rust not only makes your blade look bad, but it could also make your food unsafe to eat.
This means that this knife can stay wet for long periods of time without rusting. This is very helpful in a humid kitchen where you have to chop a lot of fish and vegetables that are wet. Even stainless steel can get rusty, but it will take a lot longer.
Wear Resistance
Standard stainless steel is quite soft, which means that scratches can ruin its shiny surface. Because it contains both carbon and molybdenum, AUS 8 steel doesn’t wear down too quickly. So, even if you cut through hard foods like crusty bread or nuts, the shiny blade won’t get scratched.
Obviously, you don’t want to make scratches happen. Don’t put the knife in a sink or dishwasher where other hard things could damage the blade. It’s also important to store a knife the right way, whether it’s for the kitchen or the outdoors.
Sharpening
A knife made of AUS 8 stainless steel keeps its edge pretty well. Once it gets dull, it’s not too hard to sharpen it again. AUS 8 steel is not very hard, so it doesn’t take too much work to sharpen it. The edge will be sharp in no time, whether you use a whetstone or an electric sharpener.
Comparison of AUS 8 Steel with Various Knife Steels
AUS 8 vs. Other Stainless Steels
The 440 series alloys are the closest stainless steel to AUS 8. Each of them has between 16 and 18% chromium and 0.75 percent molybdenum. The data suggests that a 440 steel knife is more resistant to corrosion than an AUS 8 knife. In comparison to AUS 8, which has 0.95-1.2% carbon, 400C steel has a higher carbon content, making it harder to sharpen but also providing superior edge retention. Blades made from AUS 8 and 440C steel typically cost around the same.
AUS 8 vs. Carbon Steels
1095 steel is considered to be the best pure carbon steel for knives. 1095 steel is slightly harder than AUS 8 because of its carbon concentration of over 0.9%. On the other hand, nickel is not among its ingredients. In order to make the AUS 8 alloy more durable, nickel is added to it. In addition, 1095 steel’s low chromium content greatly reduces its resistance to rust.
On the other hand, a 1095 blade is extremely resistant to bending and requires nothing in the way of upkeep. These continue to be strong selling points, ensuring its continued popularity.
Final Verdict
AUS-8 steel is used in a lot of good knives because it is in the middle between being easy to sharpen and being resistant to rust. This makes it great for people who have never bought a knife before and want to learn how to sharpen their own, as well as for workers who need a good quality knife at a good price.
