440c Vs D2:Comparison and Guide

440c stainless steel belongs to the 400 series of stainless steel. It has amazing features that make it stand out among other members of the series.

The 440c stainless steel has the highest carbon in the series, good hardness, fatigue resistance, and mechanical strength. It is widely used in varieties of the industry due to its several properties and is also useful in the production of certain materials, such as cutting tools.

On the other hand, D2 steel is a tool steel that is well suitable for the making of tools, knives, and others. It has distinct properties such as good hardness, and resistance to abrasion and deformation.

In this article, we shall take a comprehensive comparison between the 440c stainless steel and the D2 steel.


Stainless Steel:440c Vs D2

440c stainless steel is a martensitic high carbon stainless steel that has high strength, corrosion resistance, wear resistance, and perfect hardness.

However, it can achieve the highest strength, wear resistance, and hardness among all of the stainless after it has undergone some process of heat treatment.

On the other hand, D2 steel is usually a normal tool steel and knife steel. Popular ones include the Japanese designation SKD11, Uddeholm Sverker 21, German designation 1.2379, Hitachi SLD, and others.

It is imperative to note that the D2 steel is not stainless but tool steel. However, it has good corrosion resistance but is not as tough as most of the other tool steel. The D2 steel also has good wear resistance.

If the 440c stainless steel and the D2 steel are subjected to a good heat treatment process there is a high chance that the D2 steel will be a little harder and should be a bit more difficult to sharpen with a very much better edge retention and since D2 is not stainless steel, it is going to rust. D2 is composed of a bit higher carbon content in it when compared to 440c, so D2 is generally harder than the corresponding 440c.

Edge Retention:440c Vs D2

When we compare the 440c steel to that of D2 steel in terms of edge retention, D2 is better. Although D2 takes a lot of time to sharpen than the 440c steel.

However, it has better edge retention than the 440c steel. D2 is not hard to sharpen, it just consumes some more time but it produces a fiber edge and holds it better than the 440c steel.

Rust Resistance:440c Vs D2

While most stainless steels have excellent resistance to corrosive attack, the 440c stainless steel has less resistance to corrosive attack.

This is due to their martensitic structure which tends to increase their hardness but leaves them more porous to corrosive attack than the austenitic and ferritic stainless steel.

The 440c steel exhibits its best corrosion resistance when they are in its tempered and hardened form. However, if they are tempered, it can reduce their resistance to corrosive attack.

On the other hand, D2 steel has a good corrosion resistance property as they do not easily rust. Although the D2 steel is a tool steel and not stainless, simply getting them wet can not make them rust easily. This is a result of the aqueous corrosion resistance, that is, because of its resistance to corrosive attack in the water.

Hardness:440c Vs D2

440c steel is a martensitic high carbon content stainless steel with a hardness ranging from 58–60 HRC when treated.

On the other hand, D2 steel has a hardness ranging from 54 – 61 HRC when tempered with an approximate yield strength of around 275 to 319 ksi as its hardness increases.

Toughness:440c Vs D2

440c steel is a very tough steel and it is proven to have a high wear resistance which is important in making knives for use in an outdoor environment.

On the other hand, D2 steel is a much tougher steel. Even though it is not stainless steel, it has a higher toughness than most stainless steel and a better wear resistance too.

Ductility:440c Vs D2

In terms of their ductility, 440c stainless steel is brittle steel. 440c steel shouldn’t be overheated as it can reduce its ductility and toughness. Also, it shouldn’t be forged below 990° C and should be cooled slowly in a furnace, warm dry lime or ashes to room temperature, and immediately annealed.

Air cooling after forging may cause cracking of 440c steel.

On the other hand, D2 is better ductile steel and can be hardened beyond 60-61 HRC without becoming brittle on the Rockwell scale.

Sharpness:440c Vs D2

Generally, 440 stainless steel is not very ductile and does not usually have good sharpness. However, most producers of knives do use a 440c stainless steel blade and they affirm that it gives the sharpest edge with longer retention among blades of other materials while D2 steel does not have a good sharpness.

Although the D2 steel is very easy to work with, its blade cannot be differentially tempered like other high carbon content steels because it is air-hardened steel.

Strength:440c Vs D2

When we compare both sheets of steel in terms of strength, the grade 440c steel has better strength. It is capable of achieving its best strength, wear resistance, and hardness after undergoing heat treatment.

440c steel has a tensile strength of 740 – 755 MPa at 20 °C and a Yield strength of 445 MPa at 20 °C

On the other hand, the D2 steel has a compressive yield strength of about 275 ksi to 319 ksi as hardness.

Composition:440c Vs D2

440c steel has a composition of 78 – 83% iron, 16 – 18% chromium, 1 – 1.3% carbon, 1% silicon, 1% manganese, 0.8% molybdenum, 0.04% phosphorus, and

0.02% sulfur.

440c steel is primarily hardened via solid solution strengthening with the use of chromium and the precipitation hardening of carbides of molybdenum. They also have a martensite grain structure

On the other hand, D2 steel has a chemical composition of 1.40 – 1.60% of Carbon, 0.60% of silicon, 0.60% of Magnesium, 1.00% of Cobalt, 11.00 – 13.00 l% of chromium, 0.70 – 1.20% Molybdenum, 1.10% of Vanadium, 0.03% Phosphorus, 0.30% of Nickel, 0.25 of Copper, and 0.03% of Sulphur

FAQ :440c Vs D2

Which Is Better Between 440c Vs D2

Both tools are very useful tools depending on the area of the application you need them. Technically, D2 steel is just tool steel and not stainless even though it is tougher and has good rust resistance and wear resistance.

If the 440c steel and the D2 steel are subjected to a good heat treatment process, the D2 steel is going to be a little harder, difficult to sharpen, and will have better edge retention. In a nutshell, if we must decide which is better, we must first put the purpose we want to utilize those tools into consideration.

Is 440c Steel High Quality?

Yes. 440c steel is a high-quality, high-carbon martensitic stainless steel. It has high resistance to corrosive attack and rust. It has the capability of attaining the highest strength, wear resistance, and hardness of all the stainless alloy heat treatments.

How Strong Is 440c Steel?

It is also dependent on how strong you want the material to be. The 440c steel has the highest carbon content and has a tensile strength of 740 – 755 MPa at 20 °C and a Yield strength of 445 MPa at 20 °C

Is 440c Steel Easy To Sharpen?

Yes. 440c steel is easy to sharpen. And it is rated to have a Rockwell hardness of 58-60. The 440c steel takes a nice edge and is moderately easy to sharpen even for a newbie.