Steel Specifics (text courtesy of Cold Steel, Inc. and Buck Knives)
The Making & Shaping of Steel
is essentially a combination of iron and carbon. All steels contain
certain other elements in small controlled amounts, like Manganese,
Sulfur, Silicon, and Phosphorus. If nothing else is present, the steel
is referred to as plain carbon steel. Steels used for knife blades are
enhanced with additional elements and are called alloy steels. It is
these additions that give different types of steel their special
properties. Alloy steels that have additions to make them
corrosion-resistant are labeled stainless steels, and these are the
steels most frequently used in making knife blades.
making of stainless steel begins by melting steel in a furnace.
Alloying elements are added to the melt, and the molten steel is poured
into molds called ingots. Once the ingots have solidified, they are
processed in a mill to make usable shapes and sizes (plates, coils,
etc.). Buck Knives uses plates and coils, depending on the type of
steel and its thickness. Plates are turned into knife components by
laser cutting and coils are shaped into components using a fine
Properties of Steel
selection of steel for specific applications is based on the properties
of the steel and other factors like manufacturability—if the steel is
difficult to fabricate, then it is not practical for use in a
manufacturing environment. These properties are established by the
alloys added to steel and by the methods used in its manufacture. Some
of the important properties of blade steel are:
- Hardness : A measure of the steel's ability to resist permanent deformation (measured on a Rockwell Scale)
- Hardenability : The ability of a steel to be hardened (through the heat-treating process)
- Strength : The steel’s ability to resist applied forces
- Ductility : The steel's ability to flex or bend without fracturing
- Toughness : The steel’s ability to absorb energy prior to fracturing
- Initial Sharpness : The sharpness of the blade "out of the box"
- Edge Retention : The ability of the steel blade to hold an edge without frequent resharpening
- Corrosion Resistance: The ability of the steel to resist deterioration as a result of reaction with its environment
- Wear Resistance: The ability to resist wear and abrasion during use
- Manufacturability : The ease with which steel can be machined, blanked, ground, and heat-treated (made into a blade)
no single material is superior in all property categories, Buck Knives
selects materials that offer the optimum properties for the purpose
nomenclature used to describe the types of steel and their properties
is often derived from the internal structure of metals. As steel is
heated and cooled, its internal structure undergoes changes. The
structures formed during these changes are given names like Austenite
and Martensite. Martensite is a very hard structure that can be formed
by rapidly cooling certain types of steel during heat-treating. Steels
that are capable of forming Martensite are called martensitic steels,
and it is this type of steel that is of most interest to the cutlery
industry. S30V, BG-42, 154CM, 420HC and 420J2 are all martensitic
properties of steel can be altered by the addition of certain elements
to the steel during the melting process. The alloying elements that are
important to knife-making are listed with a brief description of how
they affect the steel's properties.
Carbon - is not an alloying element since it is present in plain carbon steels. Nonetheless, increasing carbon increases hardness.
- improves hardenability, wear resistance, and corrosion resistance. It
is a major element in martensitic stainless steels, which are most
commonly used for sports cutlery applications.
Molybdenum - improves hardenability, tensile strength, and corrosion resistance, particularly pitting.
- improves toughness, hardenability and corrosion resistance. Nickel is
a major element in Austenitic stainless steel that is sometimes used
for dive knives.
- improves hardenability and promotes fine grains. Grain structure in
steels is another important factor in wear resistance and strength.
Generally, fine grain structures are desirable.
Types of Steel
makers follow a precise recipe to ensure that each time they make a
particular alloy it has correct properties. The recipes are known as
Specifications, and they specify the amount of each alloy. Each alloy
recipe or type is named according to a number convention. Martensitic
stainless steels, for example, have numbers like Types 410, 420, and
Blade Steels used (courtesy of Buck Knives)
- Developed primarily for the cutlery industry by Crucible Steel, S30V
contains noticeably higher amounts of Carbon and Vanadium than does
BG-42. This increase in Carbon and Vanadium provides superior
edge-holding and abrasion resistance. S30V is the best blade steel
- Superior edge holding
- Improved ductility
- Good hardness- ideal range Rc 59.5-61
- Good corrosion resistance
- Very high amounts of Carbon and Vanadium
- A proprietary alloy of Timken Latrobe Steel, BG-42 is a
high-performance, bearing-grade martensitic stainless steel used in the
aerospace industry. Because of its high strength and ability to reach
high Rockwell hardness (Rc 61-62), BG-42 is well suited for blades that
are subjected to extreme use.
- Very good edge holding ability
- High strength
- Rockwell Rc 61-62
- Fair corrosion resistance
- Contains Vanadium, improving hardenability and a fine grain structure
||13.50 - 14.50
– 154CM is a very high carbon stainless steel with the addition of
Molybdenum. Because 154CM provides better edge retention than standard
cutlery (stainless) steels, it is a good choice for blades that require
heavier cutting applications.
- Very good edge holding ability
- Rockwell Rc 60-61
- Good toughness when double tempered
- Fair corrosion resistance
- Less expensive than BG-42 and S30V
||13.50 - 14.00
- A higher carbon version of standard Type 420 martensitic stainless
steel. The Carbon content, combined with the high Chromium content,
provides good abrasion resistance and edge-holding. This steel is not
to be confused with standard 420 stainless steel. 420HC is an excellent
general purpose knife steel when heat-treated with our proprietary Paul
Bos heat-treat process.
- Good edge holding ability
- Resharpens well
- Rockwell Rc 58
- Good toughness
- Very good corrosion resistance
- Excellent standard knife steel
|12.00 - 14.00
- A lower carbon content, general-purpose stainless steel. 420J2 has
fair hardness and corrosion resistance and high ease of resharpening.
420J2 is suited for knife blades with light to medium use and routine
- Resharpens well
- Rockwell Rc 56-58
- Good manufacturability
- Good corrosion resistance
|12.00 - 14.00
- A Chromium/Nickel/Aluminum, precipitation-hardening, stainless steel.
The alloy is used for high-strength applications requiring resistance
to salt-water corrosion. 17-7PH offers a good compromise between
Martensitic stainless steels (heat-treatable) and Austenitic (300
series) stainless steels (non heat-treatable). This is due to the high
- Moderate edge holding
- Very good toughness
- Excellent corrosion resistance
- Rockwell Rc 54-56
||Ease of Resharpening
OTHER BLADE STEELS (courtesy of Cold Steel, INC)
referred to as 8A) (some text courtesy of Cold Steel, Inc.)- The words
"stainless steel" are misleading, because, in fact all steel will stain
or show discoloration if left in adverse conditions for a sufficient
time. Steel is made "stainless" by adding Chromium and reducing its
Carbon content during the smelting process. Some authorities claim that
there is a serious performance trade off with stainless steel: As the
Chrome increases and the Carbon decreases, the steel be comes more
"stainless". But it also becomes more and more difficult to sharpen
and, some claim, the edge-holding potential is seriously impaired. We
have found that most stainless steel blades are as sharp as other
material blades and hold the edge longer. AUS 8A is a high carbon, low
chromium stainless steel that has proven, over time, to be a very good
compromise between toughness, strength, edge holding and resistance to
premium grade of stainless steel used by most custom knifemakers and
upper echelon factory knives. It is Japanese steel, owned by Hitachi
Steels. The American made equivalent of ATS-34 is 154CM, a steel
popularized by renowned maker Bob Loveless.
GIN-1 (formerly known as G2) - another low cost steel, but slightly softer than AUS-8.
- sometimes touted as the "super steel", it outlasts all stainless
steels on the market today. It is, however, harder to resharpen (due to
its unprecedented edge retention). But the tradeoff is that you do not
have to sharpen as frequently. CPM-T440V is widely used by custom
knifemakers and is slowly finding its way into high-end factory knives.
(text courtesy of Cold Steel, Inc.) Due to its low carbon high chromium
content this steel is an excellent choice for making tough (bends
instead of breaking), shock absorbing knife blades with excel lent
resistance to corrosion and moderate edge holding ability. It is an
ideal candidate for knife blades that will be subject to a wide variety
of environmental conditions including high temperature, humidity, and
airborne corrosives such as salt in a marine environment. This extreme
resistance to corrosion via its high chrome content also makes it a
perfect choice for knife blades which are carried close to the body or
in a pocket and blades which will receive little or no care or
San Mai III® (Cold Steel products)
San Mai means "three layers". It's the term given to the traditional
laminated blades used by the Japanese for swords and daggers. Laminated
construction is important because it allows different grades of steel to
be combined in a single blade. A simple way to think of this type of construction
is to imagine a sandwich: The meat center is hard, high carbon steel and
the pieces of bread on either side are the lower-carbon, tough side panels.
The edge of the blade should be hard to maximize edge holding ability, but
if the entire blade was hard it could be damaged during the rigors of battle.
For ultimate toughness the body of the blade must be able to withstand impact
and lateral stresses. Toughness is generally associated with "softness"
and "flexibility" in steel, so that, surprisingly, if a blade
is made "tough" the edge won't be hard enough to offer superior
edge holding. San Mai III® provides a blade with hard (higher carbon)
steel in the middle for a keen, long lasting edge and tougher (lower-carbon)
steel along the sides for flexibility.
VG-1 Stainless Steel (Cold Steel products)
Physical testing for sharpness, edge retention, point strength, shock,
and ultimate blade strength showed that VG-1, showed the greatest
performance increases in ability to retain an edge and proven strength
in point and blade tests, VG-1 will provide Cold Steel® customers with
superior performance previously unavailable in a stainless steel blade.
4116 Krupp Stainless Steel (Cold Steel products)
4116 is a fine grained, stainless steel made by ThyssenKrupp in Germany
and is used for hygienic applications (medical devices and the pharmaceutical
industry) and food processing which make it a superb material for kitchen
cutlery. The balance of carbon and chromium content give it a high degree
of corrosion resistance and also impressive physical characteristics of
strength and edge holding. Edge retention in actual cutting tests exceeded
blades made of the 420 and 440 series of stainless steels. Other alloying
elements contribute to grain refinement which increase blade strength and
edge toughness and also allow for a finer, sharper edge.
1055 Carbon Steel (Cold Steel products)
1055 steel is right on the border between a medium and a high carbon steel,
with a carbon content between 0.50%-0.60% and with manganese between 0.60%-0.90%
as the only other component. The carbon content and lean alloy make this
a shallow hardening steel with a quenched hardness between Rc 60-64 depending
on exact carbon content. These combination of factors make this one of the
toughest steels available because, when quenched, it produces a near saturated
lathe martensite with no excess carbides, avoiding the brittleness of higher
carbon materials. This steel is particularly suited to applications where
strength and impact resistance is valued above all other considerations
and will produce blades of almost legendary toughness.
SK-5 High Carbon Steel (Cold Steel products)
SK-5 is the Japanese equivalent of American 1080, a high carbon steel with
carbon between 0.75%-0.85% and 0.60%-0.90% manganese. As quenched, it has
a hardness near Rc 65 and produces a mixture of carbon rich martensite with
some small un-dissolved carbides. The excess carbide increases abrasion
resistance and allows the steel to achieve an ideal balance of very good
blade toughness with superior edge holding ability. Due to these characteristics,
this grade of steel has been used traditionally for making a variety of
hand tools, including chisels and woodcutting saws, and has stood the test
of time and use over many years in many countries.