By Joe Talmadge
One thing to keep in mind is that there's more to knife performance
than the steel. The blade profile is also important (a tanto format
isn't the best choice to skin a deer, for example). But perhaps most
important is the heat treatment. A good solid heat treatment on a
lesser steel will often result in a blade that outperforms a better
steel with inferior heat treatment. Bad heat treatment can cause a
stainless steel to lose some of its stainless properties, or cause a
tough steel to become brittle, etc. Unfortunately, of the three most
important properties (blade profile, steel type, heat treatment), heat
treatment is the one that is impossible to assess by eye, and as a
result excessive attention is sometimes paid to the other two.
Remember also to keep your particular application in mind. 440A is
often scoffed at, but I'd rather have my salt water dive knife made of
440A than L-6. Properly heat treated 5160 is wonderfully tough, but
if my application is skinning deer, I'm probably more interested in
edge holding ala 52100. And on and on.
At its most simple, steel is iron with carbon in it. Other alloys are
added to make the steel perform differently. Here are the important
steel alloys in alphabetical order, and some sample steels that
contain those alloys:
Carbon: Present in all steels, it is the most important hardening
element. Also increases the strength of the steel. We
usually want knife-grade steel to have >.5% carbon, which
makes it "high-carbon" steel.
Chromium: Added for wear resistance, hardenability, and (most
importantly) for corrosion resistance. A steel with at least
13% chromium is deemed "stainless" steel. Despite the name,
all steel can rust if not maintained properly.
Manganese: An important element, manganese aids the grain structure,
and contributes to hardenability. Also strength &
wear resistance. Improves the steel (e.g., deoxidizes) during
the steel's manufacturing (hot working and rolling). Present
in most cutlery steel except for A-2, L-6, and CPM 420V.
Molybdenum: A carbide former, prevents brittleness & maintains
the steel's strength at high temperatures. Present in
many steels, and air-hardening steels (e.g., A-2, ATS-34)
always have 1% or more molybdenum -- molybdenum is what gives
those steels the ability to harden in air.
Nickel: Used for strength, corrosion resistance, and toughness. Present
in L-6 and AUS-6 and AUS-8.
Silicon: Contributes to strength. Like manganese, it makes the steel
more sound while it's being manufactured.
Tungsten: Increases wear resistance. When combined properly with
chromium or molybdenum, tungsten will make the steel to be
a high-speed steel. The high-speed steel M-2 has a high amount
Vanadium: Contributes to wear resistance and hardenability. A carbide
former that helps produce fine-grained steel. A number
of steels have vanadium, but M-2, Vascowear, and CPM T440V and
420V (in order of increasing amounts) have high amounts of
vanadium. BG-42's biggest difference with ATS-34 is the
addition of vanadium.
CARBON and alloy steels (non-stainless steels):
These steels are the steels most often forged. Stainless steels can
be forged (guys like Sean McWilliams do forge stainless), but it is
very difficult. In addition, carbon steels can be differentially
tempered, to give a hard edge-holding edge and a tough springy back.
Stainless steels are not differentially tempered. Of course, carbon
steels will rust faster than stainless steels, to varying degrees.
Carbon steels are also often a little bit less of a crap shoot than
stainless steels -- I believe all the steels named below are fine
performers when heat treated properly.
In the AISI steel designation system, 10xx is carbon steel, any other
steels are alloy steels. For example, the 50xx series are chromium
In the SAE designation system, steels with letter designations (e.g.,
W-2, A-2) are tool steels.
There is an ASM classification system as well, but it isn't seen often
in the discussion of cutlery steels, so I'll ignore it for now.
Often, the last numbers in the name of a steel are fairly close to the
steel's carbon content. So 1095 is ~.95% carbon. 52100 is ~1.0%
carbon. 5160 is ~.60% carbon.
This is a steel very popular with forgers, as it has the reputation
for being "forgiving". It is an excellent steel, that takes and holds
an edge superbly, and is very tough. It rusts easily, however.
Randall Knives uses O-1, so does Mad Dog.
Reasonably tough and holds an edge well, due to its .2% vanadium
content. Most files are made from W-1, which is the same as W-2
except for the vanadium content (W-1 has no vanadium).
The 10-series -- 1095 (and 1084, 1070, 1060, 1050, etc.)
Many of the 10-series steels for cutlery, though 1095 is the most
popular for knives. When you go in order from 1095-1050, you
generally go from more carbon to less, from better edge holding to
less edge holding, and tough to tougher to toughest. As such, you'll
see 1060 and 1050, used often for swords. For knives, 1095 is sort of
the "standard" carbon steel, not too expensive and performs well. It
is reasonably tough and holds an edge very well. It rusts easily.
This is a simple steel, which contains only two alloying elements:
.95% carbon and .4% manganese. The various kabars are usually 1095
with a black coating.
Carbon V is a trademarked term by Cold Steel, and as such is not
necessarily one particular kind of steel; rather, it describes
whatever steel Cold Steel happens to be using, and there is an
indication they do change steels from time to time. Carbon V performs
roughly between 1095-ish and O-1-ish, in my opinion, and rusts like
O-1 as well. I've heard rumors that Carbon V is O-1 (which I now
think is unlikely) or 1095. Numerous industry insiders
insist it is 0170-6. Some spark tests done by a rec.knives reader
seem to point the finger at 50100-B. Since 50100-B and 0170-6 are the
same steel (see below), this is likely the current Carbon V.
0170-6 - 50100-B
These are different designations for the same steel: 0170-6 is the
steel makers classification, 50100-B is the AISI designation. A good
chrome-vanadium steel that is somewhat similar to O-1, but much less
expensive. The now-defunct Blackjack made several knives from O170-6,
and Carbon V may be 0170-6. 50100 is basically 52100 with about 1/3
the chromium of 52100, and the B in 50100-B indicates that the steel
has been modified with vanadium, making this a chrome-vanadium steel.
An excellent air-hardening tool steel, it is known for its great
toughness and good edge holding. As an air-hardening steel, so don't
expect it to be differentially tempered. Its outstanding toughness
makes it a frequent choice for combat knives. Chris Reeve and Phil
Hartsfield both use A-2, and Blackjack made a few models from A-2.
A band saw steel that is very tough and holds an edge well, but rusts
easily. It is, like O-1, a forgiving steel for the forger. If you're
willing to put up with the maintenance, this may be one of the very
best steels available for cutlery, especially where toughness is
A "high-speed steel", it can hold its temper even at very high
temperatures, and as such is used in industry for high-heat cutting
jobs. It is an excellent edge holder. It is tough but not as tough
as some of the toughest steels in this section; however, it will still
be tougher than the stainless steels and hold an edge better. It
rusts easily. Benchmade has started using M-2 in one of their AFCK
A steel popular with forgers, it is extremely popular now and a very
high-end steel. It is essentially a simple spring steel with chromium
added for hardenability. It has good edge holding, but is known
especially for its outstanding toughness (like L-6). Often used for
swords (hardened in the low 50s Rc) because of its toughness, and is
also used for hard use knives (hardened up near the 60s Rc).
A ball-bearing steel, and as such is only used by forgers. It is
similar to 5160 (though it has around 1% carbon vs. 5160 ~.60%), but
holds an edge better. It is less tough than 5160 however. It is used
often for hunting knives and other knives where the user is willing to
trade off a little of 5160's toughness for better edge holding.
D-2 is sometimes called a "semi-stainless". It has a fairly high
chrome content (12%), but not high enough to classify it as stainless.
It is more stain resistant than the carbon steels mentioned above,
however. It has excellent edge holding, but may be a little less
tough than some of the steels mentioned above. And it does not take a
beautiful finish. Bob Dozier uses D-2.
A very hard-to-find steel, with a high vanadium content. It is
extremely difficult to work and very wear-resistant. It is out of
Remember that all steels can rust. But the following steels, by virtue
of their > 13% chromium, have much more rust resistance than the above
steels. I should point out that there doesn't appear to be consensus
on what percent of chromium is needed for a steel to be considered
stainless. In the cutlery industry, the de-facto standard is 13%, but
the ASM Metals Handbooks says "greater than 10%", and other books cite
other numbers. In addition, the alloying elements have a strong
influence on the amount of chromium needed; lower chromium with the
right alloying elements can still have "stainless" performance.
Lower carbon content (<.5%) than the 440 series makes this steel
extremely soft, and it doesn't hold an edge well. It is used often
for diving knives, as it is extremely stain resistant. Also used
often for very inexpensive knives. Outside salt water use, it is too
soft to be a good choice for a utility knife.
440 A - 440 B - 440C
The carbon content (and hardenability) of this stainless steel goes up
in order from A (.75%) to B (.9%) to C (1.2%). 440C is an excellent,
high-end stainless steel, usually hardened to around 56-58 Rc. All
three resist rust well, with 440A being the most rust resistant, and
440C the least. The SOG Seal 2000 is 440A, and Randall uses 440B for
their stainless knives. 440C is fairly ubiquitous, and is generally
considered the penultimate general-use stainless (with ATS-34 being
the ultimate). If your knife is marked with just "440", it is
probably the less expensive 440A; if a manufacturer had used the more
expensive 440C, he'd want to advertise that. The general feeling is
that 440A (and similar steels, see below) is just good enough for
everyday use, especially with a good heat treat (we've heard good
reports on SOG's 440A heat treat). 440-B is a very solid performer
and 440-C is excellent.
425M - 12C27
Both are very similar to 440A. 425M (.5% carbon) is used by Buck
knives. 12C27 (.6% carbon) is a Scandanavian steel used often in
Finish puukkos and Norwegian knives.
AUS-6 - AUS-8 - AUS-10 (aka 6A 8A 10A)
Japanese stainless steels, roughly comparable to 440A (AUS-6, .65%
carbon) and 440B (AUS-8, .75% carbon) and 440C (AUS-10, 1.1% carbon).
AUS-6 is used by Al Mar. Cold Steel's use of AUS-8 has made it pretty
popular, as heat treated by CS it won't hold an edge like ATS-34, but
is a bit softer and may be a bit tougher. AUS-10 has roughly the same
carbon content as 440C but with slightly less chromium, so it should
be a bit less rust resistant but perhaps a bit tougher than 440C. All
3 steels have some vanadium added (which the 440 series lacks), which
will improve wear resistance.
GIN-1 aka G-2
A steel with slightly less carbon, slightly more chromium, and much
less moly than ATS-34, it is used often by Spyderco. A very good
ATS-34 - 154-CM
The hottest high-end stainless right now. 154-CM is the original
American version, but for a long time was not manufactured to the high
quality standards knifemakers expect, and so is not used often
anymore. Late-breaking news is that high-quality 154-CM may again be
available. ATS-34 is a Hitachi product that is very, very similar to
154-CM, and is the premier high quality stainless. Normally hardened
to around 60 Rc, it holds an edge very well and is tough enough even
at that high hardness. Not quite as rust resistant as the 400 series
above. Many custom makers use ATS-34, and Spyderco (in their high-end
knives) and Benchmade are among the production companies that use it.
Similar to ATS-34, but with the moly removed and some other elements
added. Not much is known about this steel yet, but it looks like the
intent was to get ATS-34 edge-holding with increased toughness. Since
moly is an expensive element useful for high-speed steels, and knife
blades do not need to be high speed, removing the moly hopefully
drastically decreases the price of the steel while at least retaining
ATS-34's performance. Spyderco is using this steel.
Bob Loveless announced recently that he's switching from ATS-34 to
this steel. Keep an eye out for it, it's bound to catch on. BG-42 is
somewhat similar to ATS-34, with two major differences: It has twice
as much manganese as ATS-34, and has 1.2% vanadium (ATS-34 has no
vanadium), so look for even better edge-holding than ATS-34. Chris
Reeves has switched from ATS-34 to BG-42 in his Sebenzas.
CPM T440V - CPM T420V
Two steels that hold an edge superbly (better than ATS-34), but it's
difficult to get the edge there in the first place. These steels are
both high in vanadium. Spyderco offers at least one model in CPM
T440V. Custom maker Sean McWilliams is a big fan of 440V, which he
forges. Depending on heat treatment, expect to have to work a bit
harder to sharpen these steels -- also, don't expect ATS-34 type
toughness. 420V is CPM's follow-on to 440V, and with less chromium
and almost double the vanadium, is more wear-resistant and may be
tougher than 440V.
400 Series Stainless
Before Cold Steel switched to AUS-8, many of their stainless products
were marketed as being of "400 Series Stainless". Other knife
companies are beginning to use the same term. What exactly *is* 400
Series Stainless? I always imagined it was 440-A, but there's nothing
to keep a company from using any 4xx steel, like 420 or 425M, and
calling it 400 Series Stainless.
NON-STEELS USED BY KNIFEMAKERS
Cobalt - Stellite 6K
A flexible material with very good wear resistance, it is practically
corrosion resistant. Stellite 6K, sometimes seen in knives, is
a cobalt alloy. David Boye
uses cobalt for his dive knives.
Newer titanium alloys can be hardened near 50 Rc, and at that hardness
seem to take something approaching a useful edge. It is extremely
rust-resistant, and is non-magnetic. Popular as expensive dive knives
these days, because the SEALs use it as their knife when working
around magnetic-detonated mines. Mission knives uses titanium.
Tygrys makes a knife with a steel edge sandwiched by titanium.