W2 steel review is needed for all knife users because it’s perhaps one of the most notable blade steel if high hardness and edge retention are prerequisites. W2 steel knife is respected by knife users because of the points we mentioned in our review.
If you are interested in w2 tool steel, then I hope I answer all your thoughts in this review. If you still have questions, you can always comment and we will try to reply as brief as possible.
What is meant by ‘W’ in W2 tool steel?
W is basically the term used for specific alloy steels that are water hardenable. During quenching of these alloys, the quenching medium used is water to generate maximum hardness and refined microstructure. Other than W2 alloy, W grade has two more variants including W1 and W5 steel. You can read the review on W1 tool steel if you want to compare both.
What is W2 steel?
W2 steel is water hardenable high carbon low alloy steel with a carbon percentage above 1%. This steel is most commonly used in knives, cutting tools, and large blades due to an excellent combination of high hardness, optimum toughness, and refined grain size. Out of all W-grade steels, W2 is most preferable for knife making.
W2 carbon content is above 1% resulting in high hardness. Chromium addition in this steel resulted in increased edge retention and hardness in blades and knives.
This blade steel is called high carbon low alloy steel and consists of the following elements;
|C||0.85 - 1.50|
|Si||0.10 - 0.40|
|Mn||0.10 - 0.40|
|V||0.15 - 0.35|
You can see effect of each element on properties of steel in our article, “the effect of alloying elements in steel”.
W2 Steel Properties
W2 carbon steel is used in places where a good combination of high hardness and toughness is required. Because of high carbon and water quenching, we have high hardness with Rockwell hardness approaching 60 HRC in certain cases.
Due to the nature of water hardenable structure, applications of w2 blade steel are limited to rather simpler shapes like knives. That’s why w2 alloy is most commonly known for blades and knives.
All properties mentioned below in the table are for annealed w2. After performing certain quenching and tempering treatments, you can increase the hardness of w2 steel to 58 HRC – 62 HRC.
w2 steel composition
|Physical Properties||Units (metric)|
|Melting Point||1430 C|
|Density||7.72 - 7.8 g/cm3|
|Mechanical Properties||Units (Metric)|
|Elastic Modulus||203 - 211 GPa|
|Shear Modulus||79 GPa|
|Hardness (Brinell)||202 HBN|
|Hardness (Rockwell)||14-18 HRC|
|W2 Steel||Thermal Properties in Metric Unit|
|Coefficient of Thermal Expansion||1 - 1.3 E-5 /K|
|Specific Heat Capacity||420 - 460 J/kg-K|
|Thermal Conductivity||17 - 42 W/m-K|
There is Brinel hardness mentioned which can be measured using Brinell hardness tester.
How do you heat treat w2 tool steel?
W2 is considered high carbon and low alloy, and after the manufacturing process right set of treatments is necessary to achieve the right hardness and desired physical appearance for final use.
The process of heat treatment in the case of w2 knife steel involves normalizing, annealing, machining, stress-relieving, and then hardening followed by tempering.
After forging this steel, we will use the process of annealing, normalizing to refine microstructure and homogenize the distribution of carbides. With these two heat treatments, structural changes are expected and that’s why machining is performed after these heat treatments.
After machining and final shaping, stress-relieving and hardening are performed to achieve the right hardness and knife characteristics.
Normalizing W2 steel katana
We are going to shed some light on the purpose of annealing and normalizing in the case of low alloy w2 grade. For detailed literature on both processes, have a look into the Annealing process and Normalizing Process.
Here, the purpose of the normalizing process is to produce fine and uniform microstructure with the right distribution of alloy carbides. After manufacturing, the structure is irregular and it requires the right type of adjustment to obtain optimum condition so it can be hardened to maximum properties.
Normalizing conditions are enlisted along with annealing conditions in the below chart.
how to anneal w2 tool steel?
Annealing is a process of heating steel to the right temperature and allows uniform distribution of microstructure. After uniform distribution, steel is cooled slowly. This may increase grain size and lowers hardness. With lower hardness, machining becomes easier.
Regarding the microstructure, annealed steel will have carbides distributed in a ferritic matrix. Spherodize annealing of w2 grade is used to lower the hardness and make w2 grade machinable. You can see the right process of spherodize annealing of w2 tool steel in the chart below;
You can see annealing and normalizing conditions for w2 below;
|Normalizing Temp C||790-925|
|Annealing Temp C||760-790|
|Cooling Rate during Annealing (oC/h)||22|
|Hardness after annealing||163-201|
Stress relief annealing after machining is performed to remove stresses and restore microstructure. You can read it in more detail in annealing types. Holding time should be 1-2 hours at right stress relief annealing.
how to harden w2 tool steel?
Hardening of w2 blade involves a set of three operations as we previously explained in the Quenching process i.e. Austenitizing, Quenching, and Tempering.
Austenitizing is critical in the case of low alloy tool steels because of problems like distortion, or loss of ductility. Read more in detail in Defects in steel during heat treatment.
Within high carbon steel, carbides get dissolved resulting in the austenitic microstructure. Austenitic temperature is optimized in such a way as to minimize austenitic grain growth and dissolution of carbides.
The fine structure even after austenitization is attributed to carbides of vanadium and tungsten. These carbides dissolve at very high temperatures and that is why they prevent abnormal grain growth in austenite in the case of w2 grade.
Quenching results in a fine microstructure consisting of martensite and retained austenite. The lesser the retained austenite, the harder the w2 tool blade.
Tempering steel is a very important step in all heat treatment operations. Temper w2 steel has high hardness and edge retention because of secondary hardening phenomena. This can be studied in detail in the tempering steel process.
W2 steel Characteristics
W2 steel is hardness after the process of tempering reaches 60 HRC i.e. 58 HRC – 63HRC. High hardness is attributed to alloying elements like Vanadium and tungsten which not only refine microstructure but also give secondary hardening to w2 steel during tempering.
W2 tool is high carbon and low alloy and it contains cementite microstructure in its original non-heat-treated condition. Because of such brittle content, w2 grade is not machinable. That’s why the process of annealing is developed to perform final machining before hardening.
As discussed above, the annealing process converts cementite structure into carbides in a ferritic matrix. This structure is relatively easier for a machine.
After the hardening process, the hardness of 60 HRC prevents any material operations like machining.
Because of high hardness, the blade edge will not become dull over time faster than other low carbon steel. Edge retention is excellent of w2 high carbon steel because of provided 63 HRC hardness.
Blade made of w2 tool steel is extremely hard and that also makes it difficult to sharpen. The only time sharpening of the blade is possible is after a process of annealing when the hardness of the w2 tool is at a limited value i.e. 15 HRC.
W2 alloy is known for high surface hardness and good toughness in the core region. In this way, good impact resistance is also achieved. However, increase in hardness to achieve high edge retention and wear resistance, there is a compromise on toughness. To keep the optimum value of toughness, it is recommended to have hardness lower than 63 HRC in w2 knife steel.
The corrosion resistance of carbon steel is low and the same is true for w2 alloy. To achieve a high level of corrosion resistance, you need high percentages of chromium. We recommend checkout 1095 cro-van steel or 8CRMoV and 9Cr18MoV steel if corrosion is one of the deciding factors.
|W2 steel Characteristics|
|Resistance to decarburization||Highest|
|Amount of distortion||High|
|Resistance to cracking||Medium|
|Approximate Hardness (HRC)||50-64|
|Resistance to softening||Low|
|Resistance to wear||Low to medium|
Is W2 steel good for knives?
W2 grade sounds pretty good because of its high hardness and optimum toughness value. However, this is not everything in the knife checklist, we must consider other factors as well.
W2 high carbon steel has a high hardness value and optimum toughness value which indicates it can handle a lot of damage in terms of cutting or impact. That is why the most common use of w2 grade is found in cutlery, surgical and diving knives.
In the case of fillet, kitchen or travel knives like crkt minimalist bowie hunting knife, corrosion resistance, and good wear resistance is of much important value. The knife will become dull or rusty fast and sharpening this knife is difficult because of its high hardness.
That’s why this knife is not recommended for fillet or kitchen. However, you must have seen lots of knife users still using fixed blades made of w2 grade. Well, that’s because the heat treatment is simple and it is available in the market at a lower cost.
w1 vs w2 steel
W1 steel and W2 steel both belonged to W grades. The structure of W2 is finer and harder as compared to w1 grade because of the addition of Vanadium and Tungsten. Vanadium is the main reason in the steel for high hardness and higher edge retention. W2 is more suitable for knife making than w1 grade.
W2 steel VS D2 steel
D2 steel is one of the most common cold work tool steel. Carbon percentage and hardness are similar to discussed steel. In D2 steel, after hardening and tempering, the hardness value is equivalent to 58HRC which is almost similar to this steel. One additional benefit that D2 steel has is corrosion resistance because of 11 percent Chromium. Chromium makes steel rust-free. D2 steel is more suitable for knife making than W2 tool steel provided use is in kitchen, fishing, or hunting.
W2 VS 1095 steel
1095 steel is high carbon steel with no additional alloying element. While W2 variant is also high carbon alloy but also has a small addition of alloying elements like Cr, V, W, and Mo. These alloying elements produce more fines and tougher structures with similar hardness as compared to 1095 steel. Regarding knife making, W2 alloy is better in application than pure 1095 grade.
W2 Steel VS Damascus
Damascus steel is simple forged high carbon steel similar to 1095 steel. In terms of application in the field of cutting blades and knives, w2 variant offers a better package having high hardness, better toughness, and good impact resistance than Damascus steel.
how heavy is w2 steel?
This steel has a density equivalent to simple iron. It is as heavy as any other steel blade or knife.
How long to quench W2 steel?
You can see the complete heat treatment cycle we shared here. There is no break till reaching room temperature. So, Quenching this steel in water is carried out until it reaches at least 200oC to avoid any structure and minimize retained austenite formation.
How good are W2 steel swords?
They are pretty good. The reason is a good combination of high hardness and optimum toughness. It can resist any impact or damage and also edge retention offered by structure is suitable for sword marking. You can use this steel in sword-making comfortably.
How good is w2 steel?
W2 tool contains high carbon with minor additions of Cr, V, and W. Heat treatment of this steel results in high hardness and good toughness because of carbon and other alloying elements. Knife and blades made of this steel can handle a good beating. This steel is considered good in the field of sword making, cutlery, and similar applications.
What can be used in place of W2 steel?
This steel is mainly called high carbon steel and there are a variety of other options available in the market that offer similar or better properties. We recommend checking out 1095 cro-van steel, which has good hardness along with a good amount of corrosion resistance.
What made out of W2 steel?
This steel is most commonly known for its extensive use in making blades. Fixed blades made out of w2 tool steel are used in making swords, cutlery, and surgical knives.
What is carbon content of W2 steel?
This high carbon steel has a carbon content of between 0.85 – 1.5%.