Knife Blade Steel
Knife Blade Steel
Knife blade steel come in lots of varieties and it would be great if there was some standardized way of naming them, but there’s not. I’m not going to go into every type of steel from around the world but i will talk about the most common ones that knife manufactures tend to use.
Properties of Knife Blade Steel
Some sites will list as many as 10 properties but i will just touch on the ones that matter to us. Things like hardenability really only matter to the manufacturer.
Hardness or strength is the ability to absorb energy without flexing. This is achieved by increasing the carbon content. These blades will hold an edge great but are also more difficult to sharpen. They will also be more brittle and prone to chipping. Measured on the Rockwell C scale (Rc or HRC), anything above 58 will hold an edge well but be difficult to sharpen.
Not to be confused with hardness, this will often be a trade-off from hardness. Also often called elasticity or ductility, it is the blades ability to flex without breaking. Obviously this is important for blades that will see regular use. Easier to sharpen but less edge retention.
Obviously these will be the stainless steels. Although most steel will have some degree of corrosion resistance the stainless steels have higher amounts of chromium and molybdenum. Often but not always this also sacrifices some of the edge retention abilities.
Mentioned several times already, this fairly self explanatory. Probably the most important factor to many people, it is also a result of a combination of the above factors.
Common Knife Blade Steels
The Best of the Best
Currently the top dog this steel contains huge amounts of carbon and vanadium. Very hard with great edge retention. Don’t expect to even be able to sharpen this at home. These blades are quite expensive but i will try to find some examples to include.
Made using a combination of chromium, vanadium, molybdenum and even tungsten, this is another very hard blade with great edge retention. Measuring Rc 60-62 this will also be tough to sharpen but easier than the s90v. It also has superior corrosion resistance than the s90v. This steel can apparently be polished to an incredible finish.
S35VN and S30V
The s35vn is slightly better than the s30v but most of us would find the difference unnoticeable. Both have a great balance of edge retention, hardness and corrosion resistance. This steel is what most companies such as Buck and Gerber will use as their high end steel. Still more expensive than most knives, now we are getting into a more mainstream price range.
This is used by Buck and others as a mid range steel. Similar to the 440c which you will find below, but with more molybdenum and less chromium while still being corrosion resistant. Still a fairly hard steel with great edge retention, you’re gonna still need some patience to sharpen it.
Japanese made, similar to 154cm but slightly less corrosion resistance
Harder than 154CM and ATS 34 and therefore harder to sharpen. This is also not considered a stainless steel so more care is required.
Actually quite a good steel, similar to ATS34 and 154CM, but with more chromium. It also contains vanadium which makes it harder and tougher to sharpen. Takes a keen edge.
Mid-Range and More Common
These steels are what you will find on most store shelves. Not as hard but tougher steels, they can take abuse and resist chipping and breaking. They take a good edge and can be sharpened quite easily. For a knife that will see use and abuse these should be considered first. Ideal for survival knives and hunting and camping.
Almost my favorite and i own several and can vouch for them. This is the standard metal for Buck and other companies. Better than regular 420 but higher carbon, thus the HC. A very good all around metal and one of the most corrosion resistant on the market. Companies like Buck have a special treatment that really brings out the best in this steel.
440A, B, C
This series all has more carbon than 420HC with 440C being the highest carbon content. 440C is the hardest of the series while 440A is the toughest. Harder metals with better edge retention at the expense of corrosion resistance. I own a 440A blade and have always been happy with the edge but yes it will rust if left wet.
AUS6, 8, 10
Made in Japan. Similar to the 440 series for carbon content but with some vanadium content. AUS6 is a softer steel and not really suitable.
Actually the 10 series from 1050-1095 is quite underestimated. 1095 has the most carbon and therefore harder and better edge retention while 1050 is the toughest. 1050 and 60 are used for larger blades like swords while 1095 is best for smaller blades. Compared to most stainless steels, these blades are easier to sharpen, take a better edge and even hold it longer. However they are susceptible to discoloring and rust so care must be taken and oiled when not in use. Many 10 series blades will be coated to resist corrosion. Actually in doing this research, i have decided that i need to get one of these.
If you’re writing about steel types you definitely have to include Damascus Steel. Legendary and beautiful, it is a must have for any collector.
Origins and History
Originally produced in the Middle East, production eventually expanded to much of Europe and Asia. The process for making Damascus Steel blades was a closely guarded secret for most of 800 years. Beginning in the 3rd century the production finally ceased as recently as 1750ad and the knowledge was lost.
Many myths are attributed to these blades, including the ability to cut through another blade or a rifle barrel as well as cutting through a feather in midair and the ability to maintain its sharpness through many battles. How much of this is true is unclear, however it is possible that it could have done heavy damage to a cheap blade of the era.
While the method has been lost, much is known about these blades. Most were produced from Wootz, a form of steel made in India. While the exact recipe for this isn’t known, it is believed to have been produced at temperatures as high as 2300 degrees and held there for days before being allowed to cool gradually. It was then sent to the Middle East where the blades were produced at relatively low temperatures. This allowed more carbides to remain in the blade which gave it the mottled appearance that they are known for.
The method of quenching the blades during production is also unclear and may have much to do with it renowned strength. Rumors vary from quenching the blades in the urine of redheaded boys to the urine of goats fed a diet of ferns. Some of the more grotesque stories involve quenching the blade by running it through the body of a slave. The constant seems to be that the blades were quenched relatively slowly. Most methods of quenching probably had as much to do with superstitious beliefs as well as the metallurgy.
These days any blade made by layering steels or pattern welding is called Damascus Steel. This is not to be confused with the Wootz steel. This is done by folding the near molten steel and hammering the layers together to weld them. This results in the same mottled appearance as the Wootz steel and most of its characteristics. The most famous of the layered blades are the Samurai swords of japan, which had something close to a million layers.
Pros and Cons
The layered Damascus Steel produced these days really benefit from the variety of steels available. The combinations are vast. You can combine a non-stainless metal such as 1095 with a harder stainless to bring the characteristics of both into a single blade. 1095 and 15n20 steels are a popular combination. You get out of these blades what is put into them. A good Damascus Steel blade is quite labour intensive and therefore costs more however many people claim that they will hold an edge better than a single steel knife.
If you’re buying one, be prepared to spend the money. You can buy them for $40 but you get what you pay for. I’d be ready to spend at least a couple hundred dollars. If you like to collect knives then you need one of these. They are beautiful, cost more and by many accounts perform a little better than many single steel blades.
I intend to get one and will write up a full review when i do.
Knife Steel Comparison ‘s
This knife steel comparison chart makes it easier to compare the steels. The 1-10 scales are for comparison purposes only. As you can see a blade designed to be very hard and hold an edge may not be the best at corrosion resistance and vice versa. One steel that stands out in particular is the N680. It is soft enough to be sharpened easily but stands up well on the edge retention scale compared to the others and the corrosion resistance is still very good. The 420HC and 1095 steels don’t compare well on the edge retention index but in reality they actually perform quite well. I have not included a toughness cale but you can assume that as the hardness drops that the toughness should increase.
Steel Hardness Rc Edge Retention Corrosion Resistance
. 1-10 1-10
ZDP-189 64 8.5 4
CPM M4 63 9 3
Elmax 62 8.5 5.5
D2 62 7.5 3
CPM S90V 61 10 5
M390 61 9.5 7
CTS-xhp 61 7.5 7
CPM S35VN 60 6.5 7
CPM S30V 60 6.4 7
VG-10 60 6 7
154CM 60 6 5
ATS-34 60 5 5
14C28N 59 3.4 6
CTS-BD1 59 3.4 6
13C26 59 3 4
H1 59 2 10
N680 58 6 9
440C 58 4 4.5
AUS-8 58 3.2 4.5
AUS-6 57 3 4.6
440A 57 3 5.5
420HC 58 3 8
1095 58 3 3
420 53 2.5 9