In choosing the best pocket knife you should pay particular attention to the type of steel used in the blade. Steel is really the essence of the blade and primarily responsible for how the knife performs. Steel is essentially an alloy (i.e. a mix) of carbon and iron that is often enriched with other elements to improve certain characteristics depending on the desired application.
In the knife industry different types of steel are created by varying the types of additive elements as well as how the blade is rolled and heated (i.e. the finishing process). Refer to our Knife Steel Composition Chart for more details on these elements.
Ultimately the different types of steel used in pocket knife blades result in varying degrees of the following properties:
- Strength – This represents the ability to resist deforming when subject to stress and applied forces
- Hardness - Similar to strength this refers to the ability to avoid any permanent deformations. Hardness is generally measured using the Rockwell scale.
- Toughness - The ability to resist damage like cracks or chips when being used in heavy duty applications. This also defines the steel’s ability to flex without breaking. Note that the stronger or harder the steel the less tough it will likely be.
- Wear Resistance – This is the steel’s ability to withstand wear and general abrasion during normal use
- Corrosion/Rust Resistance - This is the ability to resist corrosion such as rust caused by external element. Note that a high resistance to corrosion does involve a sacrifice in the overall edge performance.
- Edge Retention - Represents how long the blade will retain its sharpness and not require re-sharpening
Unfortunately the “best knife steel” is not simply a case of maximizing each of the properties above. The biggest trade off is balancing strength or hardness with toughness. Some blades can be made to be exceptionally hard but will shatter into pieces if you drop them onto a hard surface. Conversely a blade can be extremely tough and able to bend but will never hold it’s edge. Also it’s worth mentioning that the term ‘stainless steel’ is generally misleading as all types of steel will show some kind of discoloration if left exposed to the elements for long enough. By knowing how you plan to use the knife you will generally be able to determine the best steel for your situation.
Types of knife steel
Below we have listed the most common types of stainless steel found in knife blades today. Note that to qualify as a true stainless steel there must be at least 14% chromium.
The ultimate in wear resistance and edge retention comes with Crucible’s CPM S90V steel. As you’d expect the carbon content is very high but the secret here is the extreme quantities of vanadium, almost three times that found in Elmax or S30V. Yes it’s ridiculously expensive, and yes it requires the patience of a saint to sharpen but nothing holds an edge or withstands abrasion quite like CPM S90V.
M390 is one of the new super steels on the block, manufactured by Bohler-Uddeholm (result of merger of Austrian Bohler and Swedish Uddeholm). It uses third generation powder metal technology and developed for knife blades requiring excellent corrosion resistance and very high hardness for excellent wear resistance. Chromium, molybdenum, vanadium, and tungsten are added to promote sharpness and edge retention. M390 hardens to 60-62 HRC. Bohler calls this steel “Microclean” and it can be polished to achieve a true mirror. Easy to sharpen?…absolutely not.
ZDP-189 by Hitachi is one of the newer super steels on the block containing huge quantities of carbon and chromium that result in ridiculous levels of hardness. ZDP-189 averages around 64 HRC but some knifemakers are able to achieve upwards of 66 HRC. Of course with those levels of hardness you can expect superb edge retention but at the cost of extreme difficulty in sharpening. While it’s both harder and tougher than S30V it’s slightly more prone to corrosion. As you’d expect, ZDP-189 is not cheap.
European Bohler-Uddeholm introduced Elmax which is a high chromium-vanadium-molybdenum alloyed powdered steel with extremely high wear and corrosion resistance.
CTS-XHP from US based Carpenter is another relatively new knife steel that has very good edge retention and hardens to about 61 HRC. This is yet another powder metallurgy creation where Carpenter’s technicians have developed an extremely fine powder grain that results in excellent performance. Slightly better edge retention than S30V but a little more work required in the sharpening process.
Like all CPM steels, CPM M4 is created using Crucible’s patented Crucible Particle Metallurgy process, which provides an extremely homogeneous, stable and grindable product compared to the traditional processes. CPM M4 provides superbly balances levels of wear resistance and toughness through high doses of molybdenum (hence the “M”), vanadium and tungsten together with reasonably high levels of carbon. It can be hardened to around 62-64 HRC but note M4 steel is not considered stainless with relatively low levels of chromium. So, while this is one of the best steels around for cutting, it has to be properly cared for.
In 2009, Crucible and Chris Reeve introduced a superior version of their excellent S30V steel and named it S35VN. By using a much finer grain structure and adding small quantities of niobium they were able to improve the toughness and ability to sharpen what was already an outstanding steel in the S30V. Many would argue this is the ultimate in knife steels and you would struggle to find any steel with better edge retention, toughness and stain resistance.
Made by US based Crucible, CPM S30V (often simply referred to as S30V) steel has excellent edge retention and resists rust effortlessly. It was designed in the US and is typically used for the high-end premium pocket knives and expensive kitchen cutlery. Dollar for dollar, this is generally regarded as one of the finest knife blade steels with the optimal balance of edge retention, hardness and toughness. Pretty common these days and one of our favorites.
A nice hard steel similar to S30V originating from the US and is reasonably resistant to corrosion. It has superb toughness good enough for most uses and holds an edge extremely well. Moderately difficult to sharpen. You’ll find a lot of quality pocket knives from top manufacturers like Benchmade using 154CM steel. You may also see CPM 154CM which is technically the same alloy but produced much differently using Crucible Particle Metallurgy. The CPM process makes finer carbide particles and thus produces a superior steel with better edge retention … but whether the average user can tell the difference is arguable.
This steel can be thought of as the Japanese equivalent to the US made 154CM. Accordingly, it has very similar properties and characteristics to the 154CM and in general represents a high quality steel which has become very popular with knife makers. ATS-34 has great edge retention but is actually a little less rust resistant than the lower-range 440C steel.
The D2 steel is often referred to as “semi-stainless” as it lacks the required amount of chromium (14%) to qualify as full stainless yet it still provides a good amount of resistance to corrosion. On the flip side D2 steel is much harder than other steels in this category such as 154CM or ATS-34 and as a result holds its edge a little better. That said, it is accordingly tougher to sharpen. In fact, you really need to be a master-sharpener to get a fine edge on D2.
The VG-10 steel is very similar to 154CM and ATS-34 with slightly more chromium but also contains vanadium which makes it marginally “better” than these two. It originated not too long ago from Japan and has been slowly introduced into the American market by respect knife makers like Spyderco. It’s really hard and can get extremely sharp but also a little brittle. Overall we like this steel a lot.
N680 steel contains about 20% nitrogen making it extremely corrosion resistant. It also contains about 1.5% cobalt which allows it to be made very hard and can take a real fine edge given it is a fine grained steel. It’s ability to hold an edge is similar to 154CM. Again, this steel is all about the corrosion resistance so if you’re blade will be in frequent contact with salt water for example then this is the steel for you.
This is a stainless steel commonly used on many mass-manufactured pocket knives and represents a solid affordable all-round choice. It’s reasonably tough and wear resistant but it really excels at stain resistance. The 440C blades can be easily sharpened. It has the highest levels of carbon and chromium in this group.
AUS-8 steel is Japanese made and like the 440C is highly resistant to rust and corrosion. It’s also similarly tough but may not hold its edge as well as some of the more premium steels which carry a greater degree of carbon. Real easy to sharpen.
The MoV series of steels originate from China and comparable to AUS-8 but containing slightly higher carbon content. You typically get great value for money with this steel and good manufacturers like Spyderco have mastered the heat treatment process to bring out its best.
The 14C28N stainless steel from Swedish manufacturer Sandvik is considered an upgrade to their 13C26 described below. In fact, Kershaw asked Sandvik to make their 13C26 steel more resistant to corrosion and the result was 14C28N. In the lab you’ll find slightly more chromium and less carbon in the 14C28N but the real secret is the addition of Nitrogen which promotes corrosion resistance. Overall a very impressive mid-range steel that can be made extremely sharp. Quite possibly the best steel you’ll find on a sub-$30 production knife.
Generally considered the king of the 420 steels, 420HC is similar to 420 steel but with increased levels of carbon (HC stands for High Carbon) which makes the steel harder. Still considered a lower-mid range steel but the more competent manufacturers (e.g. Buck) can really bring out the best in this affordable steel using quality heat treatments. That results in better edge retention and resistance to corrosion. In fact, this is one of the most corrosion resistant steels out there, despite it’s low cost.
Very much like 420HC but with slightly more chromium which results in enhanced levels of wear resistance and edge retention but suffers from weaker anti-corrosion properties.
Close comparison to 440A steel with a higher carbon to chromium ratio making it generally a little harder and wearable at the expense of corrosion resistance. Still, in real world applications it’s difficult to tell them apart and they tend to perform very similarly. The 13C26 and slightly higher end 14C28N were originally developed for razor blades and as you’d expect can be “razor” sharp.
420 & 420J
The 420 steel is on the lower end of the quality spectrum but still perfectly fine for general use applications. It has a relatively low carbon content (usually less than 0.5%) which makes for a softer blade and as a result will tend to lose it’s edge quicker than higher end steels. Blades made from 420 steel will rapidly lose their sharp edge over a relatively short time period. That said, it’s typically tough with high flexibility and extremely stain resistant but it is not particularly resistant to wear and tear. As you would expect, knives made from this type of steel are generally low priced, mass produced items.
Japanese made equivalent to the 420 series steel. Generally low quality and relatively little carbon content.
Knife Steel Performance Charts
Here are my rankings for edge retention and Rockwell hardness.
What’s the deal with CPM steels?
CPM stands for Crucible Particle Metallurgy which is a process for manufacturing high quality tool steels. American Crucible Industries is the sole producer of CPM steels which are formed by pouring the molten metal through a small nozzle where high pressure gas bursts the liquid stream into a spray of tiny droplets. These droplets are cooled, solidified into a powder form and then hot isostatically pressed (HIP) where the powder is bonded and compacted. The trick here is that the HIP process ensures each of the fine particles have a uniform composition without any alloy segregation. All this results in a steel that has improved toughness, wear resistance and can be ground and heat treated with maximum effect.
What about Damascus steel?
Damascus steel originates from the middle east from countries like India and Pakistan where it was first used back in good old “BC” times. It’s instantly recognizable as it bears a swirling pattern caused by the welding of two different steels and so often referred to as “pattern-welded” steel (not to be confused with Wootz steel which is only similar in appearance). There are many myths about the strength and capabilities of Damascus steel but today it is largely popular because of its aesthetic beauty. Mostly for collectors only.
Remember, blade steel is not everything. Knife buyers should beware getting caught up in researching the perfect steel type as it is not by itself the only thing that dictates how a knife will perform. Steel analysis has become somewhat scientific that it’s easy to get caught up in the maze of statistics. Note – just because a blade is made from the premium or high-end steels listed above does not automatically mean it’s “better” than the lesser steels. The heat treatment techniques used by the manufacturer as well as the design of the blade itself play a huge role in the ultimate outcome of knife performance!
In reality, all modern steels will perform well enough for most users so consider spending more time on other aspects of the pocket knife such as how the knife handles and other features.