Steel is one of the most used materials. There isn’t just one style, though. There are many different kinds with different chemical formulas. Because of this, each material has its own strengths and weaknesses. High-quality kitchen knives can be made from many different kinds of steel.
The 400 series is a good choice for a kitchen knife made of stainless steel. It has a shiny finish, is affordable, and is very strong. The ATS-34 alloy costs more and has molybdenum added to make it stronger.
The 10 series steels are a good example of non-stainless steel that works well in kitchen knives. They can have very sharp edges at low prices. The 52100 type can be used for many things and is hard and resistant to corrosion.
Even though the names of these and other types of steel are confusing, we will explain in detail how they are named and what they are made of. We will also talk about the most common types of steel used to make kitchen knives.
What are the elements of steel?
Steel isn’t something that can be found in nature. It has been made on purpose for many generations to help people and has a lot of uses. Steel is a metal alloy, which means it is made up of many different chemical elements, not all of which are metals. Here’s a list of the things that could be in a piece of steel:
Iron (Fe)
There could be no steel without iron. Iron makes up the biggest component in all forms of steel. It is the most common metal on Earth and is a magnetic metal. It is in everything, from the center of the Earth to our blood. Iron on its own is soft and rusts quickly. So, you won’t find any kitchen knives made of pure iron. When iron is mixed with other things, it makes steel, which is a much better choice for knives.
Carbon (C)
Carbon is the second element that steel must have. This is the real difference between steel and plain iron. The amount of carbon in a steel alloy can range from less than 0.1% to more than 2% by weight.
Low carbon steel has less than 0.3% carbon, while high-carbon steel has more than 0.5% carbon. Over 1.5% is a very high amount of carbon. The amount of carbon in a steel alloy has a big effect on its properties, especially how hard it is.
Chromium (Cr)
This is another metal that comes from the earth. Even though chromium is in a lot of alloys, steel doesn’t become “stainless” until it has a certain amount of chromium. Stainless means that the steel doesn’t rust easily and break down.
There are different ways to define stainless steel, but in general, it must have more than 10% free chromium atoms. This means that the chromium atoms don’t combine with carbon to make chromium carbide. Free chromium atoms make chromium oxide on the surface of the steel, which keeps it from rusting. The total amount of chromium can be 18% or more.
Cobalt (Co)
By adding cobalt to steel, it can keep its hardness even when heated. This is especially helpful for tools that work in hot places because it means they will still work even in harsher conditions.
Tungsten (W)
The most well-known use of this element is in light bulbs. It is sometimes used to make steel because it is strong and has a high melting point. Tungsten makes steel harder to wear down and stronger when it’s hot. Because drills make a lot of heat, this is an important property.
Molybdenum (Mo)
Molybdenum makes steel less brittle, and, like cobalt, it keeps steel strong even when it gets hot.
Phosphorus (P)
This is an unwanted impurity because even small amounts can make carbon steel even more brittle. But it is sometimes added on purpose to some kinds of steel to make them stronger.
Sulfur (S)
During the process of making steel, sulfur is also made. It can make steel more brittle than it should be, just like phosphorus. On the other hand, when small amounts are added to a steel alloy, it becomes easier to work with and shape.
The most common steel types in kitchen knives
From the above list, you may have noticed that “steel” is not a simple word. If you are looking for a steel kitchen knife, you should know what the main types are. Now, we’ll look more closely at the pros and cons of each kind of steel.
Carbon steel
Composition
There’s no doubt that carbon steel has some carbon in it, but how much? All steels have some carbon in them. Mild or low-carbon steel is steel that has less than 0.3% carbon by weight. Carbon makes up 0.3% to 0.5% of the weight of medium carbon steel. Any number above this means the steel is high or very high carbon.
Carbon steel doesn’t have to be made of just iron and carbon; it can also be made of any of the other things listed in the last section (and more). But there aren’t enough of those elements to make it a different kind of steel. For instance, too much tungsten would transform steel into tungsten steel rather than carbon steel.
Properties
When carbon is added to steel, it changes the way the metal’s lattice structure works. When there is more carbon, the structure changes more, which makes the material harder. High scores on the Rockwell scale mean that something is hard and doesn’t scratch easily. Carbon steel knives are also very strong, so they don’t bend when they’re hit with a lot of force.
The problem with a blade made of hard carbon steel is that it is very brittle and not very strong. A sharp blow, like hitting the ground, could break or chip a knife that is not very strong. Hardness and toughness are not the same thing. Adding more carbon to steel makes a hard, scratch-resistant blade, but it also makes the steel less tough.
Manufacture
Carbon steel knives are often made by hand, which can make some of them cost more. High-quality Japanese kitchen knives are made by hand by skilled blacksmiths. Each knife is made with knowledge and skill gained over many years.
Differential hardening is another good thing about making knives by hand. During this process, different parts of the blade can be heated in different ways, giving them different levels of hardness. You can have a sharp edge and a soft center. This is a good compromise because the blade can absorb energy better and still have a surface that doesn’t wear down quickly.
Stainless steel
Composition
Chromium is, of course, the most important part of stainless steel. Until chromium makes up more than 10% of the mass, it doesn’t mean that steel is stainless. Some manufacturers say that 10% of the mass of stainless steel is made up of free chromium atoms.
Stainless steel alloys can have different amounts of carbon and other metals (some variants have a large portion of nickel). For steel to be stainless, chromium needs to be the second largest element.
Properties
Because it has a lot of chromium, stainless steel is shiny and looks like silver. The chromium oxide on the knife’s surface keeps moisture and air from getting into the blade and causing it to rust on the outside or inside. This is important for a knife because it is often in contact with water and foods that are salty or acidic, which could eat away at the blade.
Carbon steel is harder and stronger than stainless steel. On the other hand, knives made of stainless steel are less likely to break.
Manufacture
This isn’t usually made by hand. A lot of factories in the West make a lot of knives made of stainless steel. The shapes of the knives are cut out of sheets of stainless steel. The edges are then sharpened, and handles are added. Each knife doesn’t get nearly as much care as a high-carbon steel knife made by hand, so they tend to be cheaper.
Powdered steel
Composition
Like other types of steel, powdered steel is made up of different metals. It doesn’t have any parts that make it different from other kinds of steel. What makes this type of steel unique is how it is made and how it looks up close.
Properties
When powdered steel is made, the result is a material that is more uniform, has smaller grains, and has a very strong structure. This material is a good mix of hardness and toughness because all of the metal grains are tightly bound together. Powdered steel knives are easy to sharpen and keep their edge for a long time.
Manufacture
The way powdered steel is made is at the cutting edge of metal technology. This process no longer takes place on an assembly line or in a blacksmith’s shop. Instead, it happens in laboratories. Because of this, powdered steel knives cost a lot of money.
A liquid or gas spray is used to break up molten steel into small pieces. The liquid steel drips out of a big container and is sprayed right away by another liquid. This makes the steel harden into tiny drops. All of the solid droplets end up at the bottom of a chamber, where they are ready for the next step.
The tiny pieces of steel are then mixed together and pressed together at high pressure (below their melting point) to close any gaps. This makes a single knife-shaped ingot, which is a block of steel.
Damascus steel
Composition
Damascus is the capital city of Syria in the present day. The name comes from the fact that the city used to make metal tools back in the 4th century. The steel used to make those tools was called “wootz,” and it came from India.
Even though there are tools made from the original wootz steel, no one knows how to make more of it. So far, attempts to make the same recipe have not worked. Damascus steel is made of two or more kinds of metal, including sometimes iron and the original wootz steel.
Properties
Because its surface is wavy, Damascus steel is known for being very beautiful. Damascus steel knives are hard but flexible, and they keep their sharp edges very well, just like powdered steel knives. This is a surprising fact, given how much longer this technology has been around than the process of making powdered steel.
Manufacture
These days, Damascus-style steel is created by forging together numerous layers of steel and iron (often over 50) at high temperatures and low oxygen levels. We call this “forge welding.”
Unfortunately, there is also low-quality Damascus steel, which is made by only welding a few layers of metal together. The blade’s surface will then be treated with acid to make it look like a real Damascus blade.
What factors affect the performance of a steel knife?
The next stage is to comprehend precisely what attributes a steel knife has that enable it to function efficiently. We now know what sorts of steel are used in kitchen knives. No knife is perfect in every way, so a chef has to make some choices.
The good thing about steel is that it can be made into many different alloys. This means that knife makers can always try a new material to improve a knife’s properties.
Strength
This is the capacity of a knife to withstand permanent deformation brought on by applied forces. Tensile, compressive, and torsional strength are three different types of strength. When using a knife, you want the blade to be sturdy enough to not bend or twist as you cut.
You must be aware of the blade steel’s strength. Pushing a knife too hard could cause it to bend significantly if it is made of ductile steel. Repairing this damage will require expertise. Steel that is more brittle is used to make some knives. Although brittle knives can be powerful, once a certain amount of force is exceeded, the blade will totally snap rather than bend.
Toughness
In general, a strong material can absorb a lot of energy without suffering serious structural harm. That can indicate that the blade has a crack or ding. This is important for a chef to know in case they drop the knife.
When chopping, your cutting board will be regularly struck, thus a strong knife will work better. A bone may break if it is not sturdy enough to withstand the rapid cutting of meat by a knife into a hard bone.
Hardness
Hard materials rank highly on the Rockwell scale because they are challenging to scratch or etch. Since most meals are too soft to scratch the surface, a hard knife blade will maintain its shine for a longer period of time. Some of the strongest blades are those that are hard. However, they are also the most fragile. Toughness is lost when hardness is prioritized.
Although they can better withstand collisions, softer knives can still be scratched. Steel is most frequently hardened by adding carbon to the alloy. Unfortunately, the hardness and brittleness of steel are inversely correlated with the carbon content.
Rust resistance
Knives made of steel and metal are susceptible to corrosion. Every knife owner should make an effort to avoid this practice. Rust not only tarnishes a steel knife’s lovely silver polish, but it also has the potential to dull the edge. The food you cook could potentially become contaminated by rust.
Chromium, as we are all aware, can increase the stain resistance of blades. Strength is reduced as a result of using this substance in steel.
Blade geometry
A helpful knife is one that is sharp. Steel knives with unusually sharp blades can occasionally be produced. Compared to typical forms of steel, businesses can mill fine-grain steels (such steel powder) more thinly.
Your steel knife should ideally have a keen edge that won’t lose its edge. The longest-lasting edges will naturally be found in hard materials, but once they become blunt, sharpening them requires more work. Knife owners are faced with yet another conundrum.
Other crucial elements include the shape and bevel of the blade, which are independent of the knife’s steel composition.
How is steel graded and classified?
Steel classification systems try to put different steel alloys into groups based on what they are made of and how they behave. This process is made more difficult by the fact that major Asian and European countries, as well as the United States, have set up their own classifications.
The widely used grading system in the United States is called SAE. Carbon and alloy steels are given a 4-digit code by SAE, but stainless steels are given a 3-digit code. The first number in the 4-digit code tells you what the main alloy element is, and the last two numbers tell you how much carbon is in the alloy.
- 1XXX is some form of carbon steel (for example 1085)
- 4XXX is a molybdenum steel (e.g. 4030)
- 7XXX is a tungsten steel
- 304 is a common stainless steel
The Unified Numbering System is another way to do things (UNS). This includes steel and all other metal alloys. These grades are made up of a letter and a five-digit code. The letter is a symbol and says what the alloy is best known for. The letter “T” stands for tool steels, the letter “A” for aluminum alloys, and the letter “E” for rare earth metals.
- G00001 – G99999 is the range of carbon and alloy steels (as per SAE)
- S00001 – S99999 is the range of stainless steels
- T00001 – T99999 is the classification for tool steels
The most common steels for kitchen knives
Stainless
According to the SAE classification, a very popular stainless steel grade for kitchen knives is the 400 series. These steels include more chromium than the 300 series, but not enough to compromise the strength of the blade.
Perhaps the best stainless steel for cutlery and less expensive kitchen knives is 420 grade stainless steel. Although 420 steel knives are very rust-resistant and can be polished to a high shine, they are rather soft due to the low carbon content and will become blunt with prolonged usage.
440 steel comes in a few different kinds (440A, 440B, and 440C). All of them contain more carbon than 420, but 440C is the most coveted alloy. It is still a form of stainless steel, therefore while having a higher carbon content, it is not particularly brittle.
ATS-34 is a different common stainless steel knife grade. Large amounts of molybdenum are added to an ATS-34 knife to further increase the toughness of the blade. A premium steel alloy, this.
Non-stainless
As an alternative to stainless steel knives, the 10 series includes 1060, 1084, and 1095 (based on SAE), which are all good choices for carbon steel cutlery. This series of steels are comparatively cheap, but they are tough and hard, and they can be sharpened.
Because it has vanadium, W2 steel is very hard and fairly strong. It helps make outdoor and tactical knives.
52100 steel was originally made for ball bearings. 52100 is a type of chromium steel that doesn’t rust and doesn’t get scratches easily. This alloy works well in a variety of household and outdoor knives. Unfortunately, it’s not the hardest choice.
CPM 10V is another alloy that contains vanadium. This material is not cheap, but its combination of high wear resistance and toughness makes it useful.
Takeaway
Simply put, there is no single “best” type of kitchen knife steel.
The last list only showed a few of the steel alloys that are used to make knives. You could spend a lot of time comparing how strong each steel seems to be, but you’d never find the best. Whether you are a knifemaker, a beginner cook, an experienced cook, or an explorer, your tastes will be different.
If you want a chef knife that stays sharp and lasts a long time, a high-carbon steel knife might be your best bet.
