All About 440 Stainless Steel: How Good is 440 Stainless Steel for Swords

Stainless steel is not a single material with uniform characteristics, but rather a category of materials. There are many distinct types of stainless steel, and the one that’s appropriate for each application is crucial. 440 stainless steel is a martensitic family of metals that is commonly prized for its strength. Not only is 440 steel one of the most robust stainless steels on the market, it’s also one of the few that can be annealed, hardened, and stressed relieved. All things stainless steel are covered by Stainless Shapes’ team of experts.

Stainless steel is created by combining chromium with regular steel. This gives it the gleaming and reflective qualities associated with stainless steel, but it makes the blade more brittle as well. There are several various types of stainless steel, although most sword makers utilize 440 stainless steel to create their stainless blades. Most 440 stainless steel is simple and quick to produce, yet it is quite fragile and unable to maintain a sharp edge. If you’re going to leave your sword on the wall, they assume it doesn’t need to be very strong.

How Good is 440 Stainless Steel for Swords

There are various stainless steels that may be even better, but the most important thing to remember is that you should get a high-carbon stainless steel. You should also keep in mind that, unlike regular high carbon steel, stainless steel isn’t as good when it comes to sharpening blades. But then again, you don’t have to oil stainless steel, which is an advantage.

Mechanical Properties

How Good is 440 Stainless Steel for Swords
The ultimate and tensile yield strengths of 420 stainless steel are among the greatest in the world, as seen by its impressive ultimate and tensile yield strengths. These measures are derived from experimental stress testing, where a 440 steel sample is stretched axially and strain vs. stress data is recorded on a graph.

The yield point is the maximum amount of stress a specimen can endure before plastically deforming and failing, and ultimate strength is the highest strain a material can withstand without shattering. These variables are important in structural applications where a substance must not permanently deform under heavy weight and high stress situations where failure must not occur.

The ability of a material to resist being scratched, etched, or otherwise damaged is referred to as its hardness. There are several scales for assessing scratch resistance, including the Brinell, Vickers, and Mohs hardness scales. Steel is most often graded on the Rockwell scale of hardness because it has a Rockwell hardness of 58. This hard steel has a hardness of 60, so it’s easy to see that 440 steel is highly resilient to surface deformation.

How Good is 440 Stainless Steel for Swords

The elasticity modulus, often known as the tensile strength, is a measurement of how a substance bends and deforms when it is stretched or relaxed elastically, or non-permanently. A high modulus of elasticity implies that to stretch a material it must be subjected to a large amount of stress, which can be likened to increased stiffness. Because 440 steel has such a high modulus of elasticity, it does not readily yield to stress and so is considered rather stiff overall.

Charpy impact testing measures the amount of energy absorbed by a material during extreme situations, such as fracture or high strain. A big pendulum is swung into a notched test sample of steel, and the amount of energy absorbed by the material is measured with a gauge. High-strength materials will generally not readily absorb significant amounts of energy because they will rather fracture than break (keep in mind that brittleness rises with strength).

Because of this, most steels have a low Charpy impact score, and 440 steels are no exception. It is yet another illustration of the stiffness and strength of 440 steels, as they only absorb less than 20 Joules of energy when struck by the Charpy test pendulum.

440 Stainless Steel Properties and Types

How Good is 440 Stainless Steel for Swords
What is 440 stainless steel, and how is it different from other stainless steels? The 440 family of stainless steels is most frequently offered in long forms—bars, wires, billets, coils, and tubes are the most popular. With 440 steel, metalworking in these raw forms is very simple.

It is made of SUS410 stainless steel, which is the highest grade of cutlery steel available. It has a higher carbon content, allowing for longer edge retention when properly maintained. It can be treated to have one of the toughest Rockwell hardness ratings among other steels. Because it is inexpensive and tough, it is quite popular in the manufacture of cutlery and replica swords.

A good choice for outdoor kitchens. It’s extremely hard, but after annealing it can be molded to a significant extent. The following are some of its other characteristics:

  • High corrosion resistance
  • Heat resistance
  • Abrasion resistance
  • Heat treatable

Forging is the most difficult metalworking technique for 440 steel, according to many experts. Although 440 is forgeable, the process requires patience and attention. The metal must be heated to 1500° F before being gradually forged at a constant temperature of 1700° F.

Forging is certainly the most difficult way to work with 440 steel. Although 440 may be forged, it must be done slowly and carefully to ensure that it does not fracture. To begin, the metal must be heated to 1500° F before being forged at a constant temperature. The temperature should not fall below 1700° F.

The four grades of 440 stainless steel are generally divided into four categories. The differences between 440 stainless and the various grades are numerous. Only the amount of carbon is different among these grades, which is why they’re classified from least to most carbon content.

  • 440A

The most stain-resistant of the stainless steels, 440A stainless has the least carbon of the four types. It is the most corrosion-resistant of all four types, making it ideal for diving and saltwater usage.

  • 440B

It’s good for knives that require greater toughness than 440A, stain resistance than 440C, or both. For example, wet knives for cooking may be made of this steel.

  • 440C

The newest steel on the block is AUS-8 66, which is produced by Crucible Steel Co. in the United Kingdom. It has a high carbon content of 6.6 percent, making it one of the most carbon-dense steels in the 440 family, with almost half of all specimens having a Carbon content level of 0.5 percent or more. This is regarded to be the toughest and most desirable knife steel, especially compared to type 440A (except in aquatic settings).

  • 440F

The phrase “440 stainless” does not appear often in the context of grades. The term “440F” refers to a free machining grade of 440C. Because of the popularity of 440C, this variety was created that works better for machining but is nearly identical in composition.

Applications of 440 Stainless Steel

How Good is 440 Stainless Steel for Swords
Based on these physical characteristics, 440 steel is the best choice for items that need only strength and durability. Working with 440 is more difficult in some ways, so most common forms are rather basic. The following are some examples:

  • Blades
  • Cutlery
  • Dental instruments
  • Nozzles
  • Valve components
  • Ball bearings
  • Pins
  • Turbines

How 440 Stainless Steel Compares to Other Stainless Steels

The stiffness and strength of 440 stainless steel are the main distinctions between it and related alloys. The higher carbon content in 440 produces a much more difficult and robust product than other alternatives. Another key element to consider is whether or not you can heat treat 440 steel.

Stainless steel is a hard, corrosion-resistant metal that has been used for decades. The most popular types of stainless steel are 304 and 316—both austenitic steels that cannot be heat treated—and 440 is an excellent alternative. Finally, due to its resistance properties, 440 compares favorably to other kinds in a few specific industries such as medical and seawater applications.

There are a number of advantages to using 440 stainless steel, but it also has a few drawbacks. For example, without heat treating, 440 is less malleable and formable than other steels. This is due to its hardness.

Corrosion resistance and temperature effects

440 steels are slightly less rust-resistant than most stainless steels. This is caused by its martensitic structure, which increases hardness while lowering resistance to corrosion compared to austenitic and ferritic stainless steels. Although 440 steel rusts readily, it should not be selected solely for this reason.

It’s also worth noting that 440 steels aren’t well suited for extreme temperatures. They lose their strength when exposed to high temperatures because they over temper and become softer, and they lose ductility at temperatures below 0°C. This information is critical to any designer who wishes to use this steel in extreme environments, since 440 steel would almost certainly not be the best option.


Carbon is the component that gives steel its hardness. High carbon steel has a far superior ability to resist rust and corrosion than low carbon steel.

Many people believe that stainless steel knives don’t contain much carbon. However, is not correct. The majority of stainless steels do not have a lot, but this does not mean they aren’t there at all.

440C steel has a carbon content of up to 1.2 percent, making it extremely high-carbon steel. Because of this, it is extremely hard and sharp, making it ideal for cutting.

The high carbon content gives this steel a greater brittleness, which is exacerbated by the 420HC’s modest hardness. When compared to other stainless steels, it has a particularly brittle edge. You should exercise caution when using a knife constructed of this material.


Manganese is another hardening component that steel has. Manganese, like carbon, toughens the steel to a similar extent. It has the same impact as carbon does in lesser measure than carbon does, but it does have an effect.

When the steel is created, manganese is added to assist with the hardening process. This explains why 1% of this steel has manganese in it.


Aside from carbon and manganese, silica is another hardening component found in 440 steel. Yes, it hardens the steel, but it does a lot more. Carbon and manganese alone would be enough in this case.

The purpose of silicon is to deoxidize the blade. To prevent injuries and decomposition in their finished product, forgers incorporate silicon.


The distinction between carbon and stainless steel comes down to the use of chromium. This is the chemical that allows stainless steel to resist corrosion.

At 18 percent chromium, 440C steel has a considerable amount. This is why even after you use this knife quite a bit, it will retain its good appearance.

Molybdenum, Phosphorous, and Sulfur

Chromium, carbon, and molybdenum are the only three components in Steel 440. They account for just 0.9% of the overall composition. In terms of percentage, they all have a minor influence on your knife.

Another element that aids corrosion resistance is molybdenum. It’s another stainless steel allusion, like chromium.

Phosphorus aids in the hardening of the steel. A blade’s carbon and manganese are hardening agents, making it brittle. Phosphorus gives the steel much-needed strength so that it doesn’t shatter on impact. Finally, sulfur is a component that aids in forging. It makes it much simpler to chop and shape the steel into a blade with this stuff around.

How Strong is 440 Steel?

Because of its high carbon content, 440 steel is harder than most stainless steel knives. The shape of the knife also matters a lot, as stated in the video above. The thickness and form all have an impact on a blade’s strength. When properly forged, 440 steel is quite robust. It will not shatter when struck against concrete.

How Good is 440 Stainless Steel for Swords

Bottom Line

The two most popular stainless steels are 440C and ATS-34, which are both very easy to machine and produce. However, they are both rather fragile and unable to maintain a decent edge. Although ATS-34 is generally held to be the finest stainless steel for a sword, another type of stainless steel, ATS-34, is likely comparable or superior.

If you want to keep your blades in good shape, pick a material that is easy to care for. The most durable of the stainless steels is 420HC. It’s perfect for holding a sword if you plan on displaying it and never using it.

Stainless steels have several advantages over pure carbon steel, one of which is rust resistance. Because stainless steel has a greater amount of chromium and nickel, it resists rust better than plain carbon steel. The disadvantage of stainless steel is that common grades used in knife blades, such as 420, 440, CPM 154, etc., do not retain their form well under stress or strain. If a real sword were used the way it was intended to be used in ancient times, it would certainly be subjected to significant impacts and if constructed out of stainless steel, we would expect it to break when confronted with a strong target like armor, a shield, or another sword.

Carbon steel, on the other hand, contains vanadium, which makes it much more difficult to heat treat. Both carbon steel and stainless steel have differentially heat treated edges that keep the blade flexible in order for it to resist impact and fracture. The greatest smiths are capable of creating a carbon steel sword that is almost unbreakable under extreme stress and merely bends before returning to its original form.

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