Overview of Knife Blade Steels

Choosing the best knife for yourself and your task at hand can feel overwhelming when looking at all of the options that there are. You have to decide between steel types, blade shapes, and what the knife’s purpose is. To make this process easier for everyone, I have decided to do a beginner’s series. To start off with, I am going to define the different terms used in ranking knife steels and then go into the different popular types of steels and dig deep into their details to help you figure out which knife is your perfect option.

 

Basic Terms

For starters, there are a few different terms that I should define. First off, the Rockwell Hardness Scale, this is a scale that determines the hardness of a material by a series of tests. The lower the number of Rockwell Hardness, the softer the steel. The higher the number, the harder the steel. Often times, these numbers are paired with either “HRC” or “RC”. These terms just say that the number is on the Rockwell Hardness scale, just two different ways of saying that. With steel, the hardness is often described as the strength of the steel.

Another important aspect is toughness. Often times, hardness and toughness are used as synonyms, however there is a difference.  The toughness of a knife is referring to how much force the blade can endure before chipping, cracking, or breaking during heavy use. The thing about toughness and hardness is that the harder a knife is, the less tough it will be and vice versa.

The third main factor in steel is corrosion resistance. Corrosion resistance is how well the knife holds up to rust and other discolorations of the steel.

While hardness, toughness, and corrosion resistance are the three main factors in steel, there is another factor in choosing which steel to purchase. The edge retention of a knife’s steel. This is used when describing how long the blade will stay sharp after a period of usage.

 

Different Types of Steel

Now that we all understand the basic terms used to describe the steels, let’s focus on the individual types of steel that can make up a knife blade.

S30V

One of the more popular types of steel for knives is S30V steel. S30V steel is a stainless steel that is considered premium knife steel. The Rockwell Hardness level is 59.5-61. The steel has 1.45% Carbon, which is a relatively high amount of carbon in a steel. This steel was actually designed to be used in knives, specifically high-end pocket knives and kitchen knives. This type of steel has fantastic wear resistance, and based on how tough it is, it is surprisingly hard. Because of how tough and hard it is, it is considered one of the best choices for knife making. Knives made with S30V steel have great edge retention, however, this knife is harder to re-sharpen. Because of the durability and edge retention, knives with S30V steel are a great option for everyday carry knives, they last long and can take a beating to tackle the harder tasks.

AUS 8

Another popular steel used in knives is AUS 8 steel. This steel is also referred to as 8A steel.  The Rockwell Hardness level is 57-58. One of the biggest pros about AUS 8 steel is how well it can hold an edge. It is also extremely easy to sharpen. This type of steel has .75% carbon, so this means that it is a relatively hard knife. This is a cheaper knife and for the price, it has great corrosion resistance capacities. Overall, this type of steel has a good balance of toughness, strength, edge holding, and resistance to corrosion, especially for the price. Because of its lower price, it won’t hold up forever, but is great if you are looking for a cheaper option.

1095

1095 steel is a great option for a cheaper cost. The Rockwell Hardness level is 56-58. This steel is very easy to sharpen and to get extremely sharp; however, it only has average edge retention. It has about 1% carbon, so it is very tough, meaning it’s extremely resistant to chipping. Because it’s so tough, it makes it an ideal candidate for survival knives and heavier duty fixed blades. Because 1095 steel is tougher than most knives, it can take more of a beating and isn’t commonly chosen for every day carry knives.

154 CM

This steel was originally designed for jet engine fan blades, but has made an appearance in the knife business because it is tough, has a good edge holding capacity, and has good corrosion resistance. This is a stainless steel with 1.05% carbon content. Surprisingly, this steel has very good toughness for how hard it is. The Rockwell Hardness level is between 58-62. It is a good option if you don’t want to pay the cost of S30V steel. 154 CM steel is fairly easy to sharpen as long as you have the right equipment. Knives made with this steel are great for general tasks, but they excel at heavy duty cutting applications.

ATS 34

ATS 34 steel has a carbon content of 1.05%. The Rockwell Hardness level is 60-61. This steel is a Japanese steel and people consider 154CM the American equivalent of it. This steel is a high quality steel that is being used in many custom knives. The edge holding properties in this steel is good, but it is moderately hard to sharpen. The steel has a high corrosion resistance, and these knives are mainly for general use.

VG-10

VG-10 steel was originally used for kitchen cutlery, because it is one of the highest levels of stainless steels. This is also because this steel holds a great edge and has a fantastic anti-rust property. The carbon content in this steel is around 1%. This steel is one of the hardest steels and because of this, it can get brittle and chip. VG-10 steel contains vanadium which is what gives it the extra toughness. Because of the high quality of its stainless properties and its strength, VG-10 is sometimes known as a super steel. This steel is very similar to ATS-34 and 154CM steel. The Rockwell Hardness is 60. VG-10 steel originated in Japan and was first introduced in America by Spyderco. While the cost might seem steep when first looking at it, you get what you pay for and it is well worth the extra money.

420 HC

The “HC” in this steel stands for High Carbon, because this steel has an increased carbon content compared to regular 420 stainless steel. 420 HC steel has a carbon content around .4-.5%. This knife has a good toughness, but very good corrosion resistance; in fact, in spite of the low cost, this steel has some of the most corrosion resistance properties out of all the steels. Because this steel is so soft, it is very easy to sharpen. The Rockwell Hardness level is a 58. Knives with this steel are a great budget option and are mainly for general use.

BG-42

This steel has a carbon content of around 1.15%, meaning that it has high strength and a great edge holding capacity. The Rockwell Hardness level of this steel is between a 61-62. This steel has average corrosion resistance properties. BG-42 steel is easy to sharpen. This steel is becoming more popular because custom knife makers have begun to use this steel more often. This steel has been used in the aerospace industry, so it is a high performance steel, and is great for knives that have to take a severe beating.

440 A

This steel has a carbon content of around .67%. This is a stainless steel and it is low cost. This steel is similar to 420 HC, but since it has a higher carbon content, it has better levels of edge retention and wear resistance. The Rockwell Hardness level of this steel is between a 55-57. This knife is very easy to sharpen and is used mostly for general use.  Out of all the 440 steels, it is the most rust resistant. Knives with this type of steel have a good balance of corrosion resistance, edge retention, and easy re-sharpening, making them a great option for every day carry.

440 C

440 C steel has a carbon content that ranges between .95-1.2%. It is a hard steel, with average toughness and wear resistance. 440 C steel very easy to sharpen and can get a very sharp edge. The Rockwell Hardness level on this steel is 58-60. One of the pros of having your blade made of 440 C is that it has extremely high resistance to stains. Out of all the 440 steels, it has the highest levels of carbon. This steel is considered to be a high end stainless steel. This type of steel was once considered the high end of knife steels, but recently it has been dropped down the list because of so many new types of steels that can be manufactured. Knives with 440C steel blades can be mass produced, so you can get them at a lower price than many other types of steels. These knives are mostly for general use.

D2

D2 steel is often referred to as “semi stainless steel”, because while it does have a high chromium content, it doesn’t have enough chromium to be categorized as fully stainless steel. However, it does still have a very good amount of resistance to corrosion. This steel also has an excellent edge retention, but it is harder to sharpen than most. However, because it is harder than other stainless steels, it does hold its edge better than the other stainless steels. The Rockwell Hardness level is between a 59-60.  Knives with this type of steel are good for general use.

Damascus

While Damascus steel is a popular steel, it is very different than any of the other steels that we’ve been discussing. This steel is made out of two or more layers of different types of steel and “folding” them together. Folding, is just a specific type of welding, where the different layers of steel are fused together. After these layers are fused together, the steel is etched with acid. Because the acid reacts differently to the two different types of steel, it reveals a striped pattern out. Knives with Damascus steel has a high toughness, but the process is long and the cost of production is high. This means that Damascus blades are usually just used for the aesthetic in decorative blades. Damascus is actually considered a precious metal. These knives are usually collector’s knives. The Rockwell Hardness level of Damascus steel is a little bit trickier because there are different types of steels in it, but they usually range from a 53 to 62.

M2

M2 steel is used in cutting tools; this metal is used to cut metal. This steel has a carbon content of about .85%. This holds an edge really well, but on larger knives, it can make them brittle. But, M2 steel is hard to sharpen. The Rockwell Hardness level of this steel is a 62. This has fantastic strength, good toughness, and is extremely high in its wear resistance properties. This steel has poor corrosion resistance properties and will often be covered in a corrosion resistant coating.

 

Conclusion

When first looking at buying a new knife, the options can seem overwhelming, especially with all the different types of steels. To choose the one that is right for you, you must consider what you are using the knife for. You have to choose the right balance between strength, toughness, wear resistant, stain resistant, how well the knife retains its edge, and the price. Sometimes you have to give in an area to have a higher content in a different area. You can usually find a budget steel without giving up too much on quality.

Now that we have tackled the popular steels and what they are best used for, stay tuned for articles breaking down the different blade shapes and handle materials.