knife metals
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SpookyPistolero
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http://zknives.com/knives/articles/knifesteelfaq.shtml
If it's of help, the only stainless I will use is the VG10 used in Fallkniven knives. All my other custom bush knives are O1 or 1095. I doubt I'll ever have another made in anything other than O1. D2 is a pain in the arse to sharpen, as is 3V. The D2 doesn't seem to hold an edge that much longer than O1 to justify the extra sharpening time. 3V is tough as nails and less likely to chip in thin edges.
If it's of help, the only stainless I will use is the VG10 used in Fallkniven knives. All my other custom bush knives are O1 or 1095. I doubt I'll ever have another made in anything other than O1. D2 is a pain in the arse to sharpen, as is 3V. The D2 doesn't seem to hold an edge that much longer than O1 to justify the extra sharpening time. 3V is tough as nails and less likely to chip in thin edges.
mgregg85
Member
I prefer 1095 carbon steel. It is tough, easy to sharpen and holds an edge well.
Stay away from almost all stainless steel knives. The only good ones are going to be prohibitively expensive. Unless you are a salt water scuba diver you probably don't need a stainless knife.
Stay away from almost all stainless steel knives. The only good ones are going to be prohibitively expensive. Unless you are a salt water scuba diver you probably don't need a stainless knife.
Gordon
Member
Ok there is O1 Steel, then there is O1 steel.
Seriously 440c is nice looking stainless and really is pretty stainless , if one must have stainless with it's soapy cutting edge . 154CM is about the same. SV30 stuff is good steel to make a knife out of for the makers, like working with surf board styrofoam and about the same strength too, but real hard to sharpen! D2 can be very hard and tough, moderate hard to sharpen it breaks with impact or bending however,but I do have a few of these. There are a lot of exotics and decent alloys like 1095, but for me the sun rises and sets on 01 .
Seriously 440c is nice looking stainless and really is pretty stainless , if one must have stainless with it's soapy cutting edge . 154CM is about the same. SV30 stuff is good steel to make a knife out of for the makers, like working with surf board styrofoam and about the same strength too, but real hard to sharpen! D2 can be very hard and tough, moderate hard to sharpen it breaks with impact or bending however,but I do have a few of these. There are a lot of exotics and decent alloys like 1095, but for me the sun rises and sets on 01 .
JTW Jr.
Member
Really ? Define prohibitively expensive if you would please.
I see plenty of sub $200 custom knives made from Ats-34 , 154cm , cpm154 and s30v.
As far as D2 being a pain to sharpen , I don't find that to be the norm. As with any steel , edge maintenance is key. I have no problem taking D2 from no edge at a thickness of say.015 to a sharp edge , so I can't see how maintaining it will be much of a problem.
Bod Dozier and Tom Krein and a host of others have no problems with D2.
There are many good choices of steels to be used for knives , 1095 is good if heat treated correctly , but to get the most out of it , you need to know what you are doing. Simple heat to non-mag and quench in motor oil or similar is not going to provide the best results.
To tell someone to stay away from stainless steel knives , as the only good ones are too expensive indicates that you haven't been shopping in the correct places
It isn't that simple. You can't determine how "good" a knife is just based on the blade steel any more than you can know how good a gun is just based on the barrel steel.
The 3 critical characteristics for a blade, material, heat treat, geometry, determine how "good" a knife is for a specific application.
You can say that some steels are not optimizable for a given knife application. 440C doesn't make a good chopper because it can chip on impact when hardened to hold an edge. It can also be overhardened and can be kept a little soft to give a blade different performance. 1095 makes for tough sharp blades that hold an edge well, but it rusts so using around food and saltwater will stain it and it requires more care to keep it from rusting. On and on.
Look at Joe Talmedges FAQs articles at AG Russell's site on Blade Geometry and Steel and see if that doesn't help give a better understanding of what goes into optimizing a blade for a given application.
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bikerdoc
Moderator In Memoriam
There is no easy way to gain steel and shapening education. You just got to study, research, and ask questions. The above mentioned steel and sharpenening sources are a good place to start.
RobertRogers
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Then, of course, is the quality of steel itself which can vary even between batches. I have discovered this the hard way when working with many metals including steel and aluminum.
45crittergitter
Member
Part 1
A-2: An excellent air-hardening tool steel with 5% Cr, known for its great toughness and good edge holding. Its outstanding toughness makes it a frequent choice for combat knives. Deeper hardening and more wear-resistant than O-1, and holds a keener cutting edge. More readily machined than high C, high Cr grades.
ATS-34: Japanese high carbon, high chrome/moly stainless by Hitachi. 13½-14½% Cr. Very good combination of sharpening, edge-holding, rust resistance and strength. See 154-CM. Superfine grain structure = edge holding. Rc 60-62.
ATS-55: Similar to ATS-34, but with the Mo removed and some other elements added. Not much is known about this steel yet, apparently intent was ATS-34 edge-holding with increased toughness at a lower price.
AUS-6 or 6A: Japanese medium to high carbon stainless. .65% C. Basically 440-A with added V. Tougher than ATS-34, 440-C, ATS-55, etc., but still holds a good edge. 440-C is better. Particularly well suited for heavier, longer blades that are subjected to a lot of stress while chopping and hacking.
AUS-8 or 8A: Japanese low carbon, high chromium stainless roughly comparable to 440-B. .75% C. Has some V, which 440-B lacks. Good compromise between toughness, strength, edge holding and resistance to corrosion. As heat treated by Cold Steel, won’t hold an edge like ATS-34. According to Cold Steel, the only equal to AUS-8 in strength and toughness is AUS-10.
AUS-10 or 10A: Japanese high carbon stainless roughly comparable to 440-C, with slightly less Cr. 1.1% C. Has some V, which 440-C lacks. Equal in strength and toughness to AUS 8, but has an additional 20% in edge holding ability, giving it a claimed wide performance advantage over ATS-34, ATS-55 and 440V.
BG-42: Stainless bearing steel, but will rust. BG-42 is 440-C modified with the addition of 3.5% Mo and 1.2% V for added wear resistance and hardness retention at high heats. Best(?) edge holding steel. A VIM/VAR ingot steel. The blade gains advantages in toughness and grain structure by using ball bearing steels. Has a fine grain structure and takes and holds an exceptionally sharp edge. Can be hardened to Rc 60 which will hold a thin edge. Doesn’t finish as smooth as ATS-34. Chosen for its high V content and tight carbide structure. American steel, manufactured in Latrobe, Penn. Greg Lightfoot recommends it highly. Chris Reeve has tested this steel extensively and believes it to be superior to anything else available on the market, including ATS-34. Has a higher Cr content (14½%), superior edge-holding ability, hardness and brute strength. Offers about the best balance of properties for a stainless steel - that or CPM 420V. Not as tough as some of the toughest steels here; however tougher than the stainless steels and holds an edge better. No stainless is really that tough, compared to a non-stainless tool steel like A-2 or CPM3V. Will hold an edge longer, and get sharper than 420V. Use 56-60 Rc, but starts to get brittle at 60 Rc. At 61 Rc, BG-42 is going to get sharper, but, the 420V has the advantage of working at a lower hardness. Both will offer about equal corrosion resistance-they are exceptionally pure, clean steels, and have roughly the same free Cr. Either of these steels rules over ATS-34. A bit more expensive than ATS-34.
Carbon V: High carbon, low alloy cutlery grade steel, “specially treated” with precise heat treatment to make it extra tough, with good edge holding capability. A trademarked term by Cold Steel; not necessarily one particular kind of steel, rather, it is whatever steel Cold Steel happens to be using at the time. Performs roughly between 1095-ish and O-1-ish, and rusts like O-1 as well. Rumors are that Carbon V is O-1 (unlikely) or 1095. Numerous industry insiders insist it is 0170-6. Some spark tests seem to indicate 50100-B. Since 50100-B and 0170-6 are the same steel (see below), this is likely the current Carbon V. Carbon V knives are hardened to Rc 59.
Ceramics: Usually very very brittle, and cannot be sharpened by the user; however, they hold an edge well. Not as sharp as the best steels. Kevin “Mad Dog” McClung recently came out with a ceramic composite knife blade that much tougher than the previous ceramics, tough enough to actually be useful as a knife blade for most jobs. It is also user-sharpenable, and holds an edge incredibly well. Zirconia is a material of great hardness included in ceramic used in making ceramic blades and used as grain on grinding belts for grinding knives. Böker ceramic is zircon oxide.
Cera-Titan: Titanium, ceramic & silver. Gives up a little of ceramic’s edge holding for less brittleness, but better edge holding than top stainless. Holds an edge like ceramic with toughness closer to steel.
Cobalt & Stellite 6K: A flexible material with very good wear resistance, it is practically 100% corrosion resistant. Has an edge-holding capability that far exceeds even the best of today’s stainless steels. Stellite 6K, sometimes seen in knives, is a cobalt alloy. See Talonite. (David Boye)
CPM T420V (& CPM T440V): Offer about the best balance of properties for a stainless steel-that or BG-42. Holds an edge not as long or sharp as BG-42, but better than ATS-34. Edge holding ability is said to be 2 - 3x better than 440-C at 57 - 58RC. There are a few other powder metal steels that will give similar performance but none that are measurably better at edge holding. However, it’s difficult to get the edge there in the first place. Depending on heat treatment, expect to have to work a bit harder to sharpen these steels. Works at a lower hardness. Less tough than ATS-34. Exceptionally pure, clean steel. Both high in V. 420V is CPM’s follow-on to 440V, and with less Cr and almost double the V, is more wear-resistant and may be tougher than 440V. Rc 56-57.
CPM 10V: Another CPM steel. Edge holding ability is said to be 2-3x better than 440-C at 57-58Rc. Toughness equal to M-2 and D-2, with increased wear resistance.
CPM S30V: Premium American cutlery stainless. Powder made with uniform carbide distribution structure and clean steel properties. Excellent corrosion resistance. Extremely fine grain, excellent edge retention and superb edge qualities. The V content allows for the formation of vanadium carbides resulting in edge holding that is independent of hardness. Wide range of applications depending on heat treatment. 2-3 times the pry bar strength of 154 CM. Some judge superior to ATS-34 and BG-42. Hot new steel.
Damascus: Remarkable toughness and edge quality.
Damasteel RWL34/PMC27: Made with powder metal technology and has no welds as with traditional Damascus steels. Two or more different metals in powder form are fused together with heat and pressure. Damascene steels consist of two different steel grades, welded in over a hundred layers. After etching, one of the steel grades turns dark and a beautiful pattern appears on the surface.
D1.4: Solingen stainless.
D2: High carbon, high chrome tool die steel. THE outstanding high C, high Cr tool steel for general use. The most important characteristic of this air hardening tool die steel is its resistance to wear or abrasion. “D” series steels are classed as Cold Work Tool Steels, high C, high Cr type. Very tough, but may be a little less tough than some of the other steels mentioned. Holds an edge very well, possibly better than BG-42. High impact resistance. Takes hard use well (chopping). Cuts and holds an edge better than most steels, including M-2, 1095, AUS-8, ATS-34 and VG-10. Fairly high in Cr (12%). Good corrosion resistance, but will pit and rust. Sometimes called a “semi-stainless.” Does not take a beautiful finish. Outstanding knife steel; one of the few that is “tougher than a cob” at 60-61 Rc. Can be hardened far beyond the favored 60-61 Rc. 440XH is stainless D-2.
Duratech 20-CV: Very stainless (20% Cr). Very high corrosion resistance, tough, very good edge holding.
G-2 or GIN-1: Stainless with less C and more Cr and much less Mo than ATS-34. Offers nearly the same qualities as 154-CM or ATS-34 but is slightly more corrosion resistant. Very good stainless steel. Cheaper.
H1: A high-Cr stainless which offers 100% corrosion resistance in both salt and fresh water. Tradeoff is good edge quality and good edge toughness. Good rescue/dive/emergency knife.
L-6: A band saw steel that is very tough and holds an edge well, but rusts easily. Like O-1, it is 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 desired.
M-2: High speed non-stainless steel. Very tough tool grade steel used for cutting steel. Tougher, sharper, and holds an edge better than ATS-34. High impact strength with incredible edge holding properties, but perhaps more brittle than typical premium blades. Extraordinary abrasion resistance and superb toughness. At a Rockwell hardness of 62 Rc it exhibits extreme toughness, with no signs of brittleness, and edge retention that is superior to most other blade materials. Works well at 62-66 Rc. Highly susceptible to corrosion and will rust unless properly maintained.
M-4: Chemical content nearly identical to M-2 except for 4% V instead of 2%; is capable of nearly twice the wear life.
MBS-26: Japanese oil-quenched stainless.
N690: An Austrian made stainless, comparable to 440C in performance and value. Keen edge qualities with excellent corrosion resistance.
O-1 and O-2: The most widely used general purpose oil hardening tool and die steels. Good combination of hardness and toughness. Strong, takes a very good edge, sharpens very easily. Superior edge to ATS-34 and 440-C. Very popular with forgers; has the reputation for being “forgiving.” Excellent steels that take and hold an edge superbly, and are very tough. Rusts easily. Use Rc 56-57.
RWL34: A Swedish powder metal stainless.
San Mai III: San Mai means “three layers.” Provides a superior blade with hard (higher carbon) stainless steel in the middle core/edge for a keen, long lasting edge inside two layers of tougher (lower-carbon) spring tempered stainless steel along the sides for flexibility and support. 25% stronger than AUS 8A.
Sandvik: A tool steel made in Sweden. Swedish steel has always been a premium steel for tools because the iron ore is very clean, that is, with very little sulfur or phosphorus.
Sandvik 13C-26: High carbon stainless tool steel.
Sandvik 19C27: High carbon, high chromium stainless. At 60-62 Rc the steel is highly wear resistant for edge holding and corrosion resistance.
Sandvik LV-04: Closed-die-forged high carbon stainless tool steel.
T15: A “Super High Speed Steel.” Not suitable for knives.
T5MOV: High carbon stainless.
Talonite/Stellite: A cobalt-chromium alloy formula based on Stellite, now owned by a Canadian firm. This material is many times as wear resistant as the finest knife steel, and contains no iron, which also makes it rust free and non-magnetic. Low on the Rockwell scale but excellent abrasion resistance. Will hold an edge as well as stellite; many times better than even the best stainless steels on the market today. Not hard to sharpen. Totally rust resistant and will hold surface qualities over hundreds of years of exposure to corrosive elements. Has a matrix of carbides in the alloy that give this material its performance characteristics. When the cutting edge feels dull to the touch, it will continue to cut due to the presence of the carbide matrix. Slightly softer than stainless steel, making it easier to sharpen. Ni 3% max, Si 2% max, Fe 3% max, Mn 2% max, Cr 28-32%, Mo 1.5% max, W 3.5-5.5%, C 0.9-1.4%, balance Co. See Cobalt & Stellite.
Titanium: Newer titanium alloys can be hardened near 50 Rc, and at that hardness seem to take something approaching a useful edge. Extremely rust-resistant, and non-magnetic. Slightly lighter than steel, extremely strong and resilient.
Vascowear: A very hard-to-find steel, with a high vanadium content. Extremely difficult to work and very wear-resistant. Out of production.
VG-10: Produced by a small foundry in Honshu island in Japan. An ingot steel. A good combination of “stuff” carefully blended. Cutting performance similar to ATS-34, but without quite the same brittleness and sharpening difficulties. Looks like a real winner of a steel, only seriously outperformed by carbon steels and particle stainless types. Edge holding below O-1 and D-2 on soft materials. Significantly superior to ATS-34 & 55 in corrosion resistance. In edge retention, at least as good as and often better than ATS steels. VG-10 is today’s hot new stainless steel for heavy duty folders, said to hold an edge better than ATS-34. It will certainly hold an edge better than AUS8A.
W-1: The same as W-2 except for the V content (W-1 has no V). Most files are made from W-1, also called a spring steel.
W-2: Reasonably tough and holds an edge well, due to its 0.2% V.
X15 T.N: French steel developed for jet engine ball bearings and scalpels. Superior rust resistance, with ample edge retention and an easy to maintain edge. Great for salt water environments.
XT70: Stainless, 55 Rc. (Katz)
XT80: Stainless, 59 Rc. Excellent ability to retain an edge, claimed better than 440-C or ATS-34. Probably a version of 440-C, with about 1% C and 12-14% Cr. (Katz)
Z60CDV14: A clean high carbon Swedish stainless. Higher in Ni and Mo than AUS-8, with a little less C. Good balance between ease of sharpening and edge retention.
9Cr14MoV: Chinese made steel similar to AUS-8. Value steel.
9Cr13CoMoV: Chinese made high-carbon stainless with increased Co for greater edge retention. High level of corrosion resistance. Good value.
154-CM: High carbon, high chrome/moly stainless, nearly identical to ATS-34, but possibly superior, made in USA by Crucible Steel for tough industrial applications. Also called 440-C Modified. Exceptional wear resistance. Has super-fine grain structure for excellent lasting edge sharpness. Normally hardened to around 60 Rc, it holds an edge very well and is tough enough even at that high hardness. Good all-around qualities. Great corrosion resistance, though not quite as rust resistant as the 400 series.
300 Series and “Surgical stainless”: Useless cutlery stainless.
“400 Series” Stainless: Probably 420J2 or 440-A, but there’s nothing to keep a company from using any 4xx steel, like 420 or 425-M, and calling it 400 Series Stainless.
410: Worse than 420J2
420J2: Softer, cheaper, ~0.15% carbon stainless tool steel, with Rc <53-55??
420: Lower carbon content (<0.5%) than the 440 series makes this steel extremely soft, and it doesn’t hold an edge well. Used often for diving knives, as it is extremely stain resistant. Also used often for very inexpensive knives. Outside of salt water use, it is too soft to be a good choice for a utility knife.
420HC: 420 High Carbon. Buck has ion fused some of its 420HC SS blades with titanium (or zirconium?) nitride (TiN) to produce a surface that is >80 Rc and holds an edge five times longer than standard blades. Performs well with proper heat treatment.
425-M (& 425?) & 12C27: Both are very similar to 440-A. 425-M has 0.5% C. 12C27 (0.6% C) is a Scandanavian steel used often in Finish and Norwegian knives. Cheap stainless. Soft and malleable?
440-A: Mid grade stainless. Most “plain” 440 is 440-A. Rc 56-59.
440-C: High grade (Solingen) high chromium stainless that holds edge well, not too hard to sharpen, doesn’t rust. Terrific balance of good hardness and corrosion resistance. Better than 440-A. Most popular. Use Rc 58-60.
440-C Modified: Same as 154-CM.
440-A, 440-B, 440-C: The carbon content (and hardenability) of this stainless steel goes up in order from A (.75%) to B (.9%) to C (1.2%). 440-C is an excellent, high-end stainless steel, usually hardened to around 56-60 Rc. All three resist rust well, with 440-A being the most rust resistant, and 440-C the least. A knife marked with just “440” is probably the less expensive 440-A; if a manufacturer had used the more expensive 440-C, he’d want to advertise that. Generally 440-A (and similar steels) is just good enough for everyday use, especially with a good heat treat (SOG). 440-B is a very solid performer and 440-C is excellent.
440XH: Stainless D-2.
SAE rates steel with a four-digit number. The first two digits refer to the steel “group,” the second pair to the amount of carbon present in 10ths of a percent. 1095 ~0.95% C, 52100 ~1.0% C, 5160 ~0.60% C. In the SAE system, steels with letter designations (W-2, A-2) are tool steels. In the AISI steel system, 10xx is carbon steel, any other steels are alloy steels. Ex: the 50xx series are chromium steels.
10XX, 11XX, 12XX, 15XX: The carbon steel group, a basic multi-use steel.
The 10-series; 1095 (and 1084, 1070, 1060, 1050, etc.): 1095 is the most popular for knives. 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. 1060 and 1050 are used often for swords.
1084: A good all around steel that holds an edge well when properly hardened and drawn.
1095: Sort of the “standard” carbon steel, not too expensive and performs well. Reasonably tough and holds an edge very well. Rusts easily. A simple steel, which contains only two alloying elements: ~0.95% C and 0.4% Mn. The various Kabars are usually 1095 with a black coating.
5150: Medium carbon, low alloy steel. Ideal for heat treated blades that have a very thick cross section such as tomahawks, axes, etc. Use 55-60 Rc. Extremely tough and impact resistant. (Cold Steel ‘hawks)
5160: A tough, springy steel popular with forgers, it is extremely popular now and a very high-end steel. Essentially a simple spring steel with Cr added for hardenability. 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) and large knives because of its toughness, and is also used for hard use knives (hardened up near the 60s Rc).
0170-6 & 50100-B: Different designations for the same steel: 0170-6 is the steel maker’s classification, 50100-B is the AISI designation. High C, low Cr steel with a Rc of 58. A good chrome-vanadium steel that is somewhat similar to O-1, but much less expensive. Carbon V may be 0170-6. 50100 is basically 52100 with about 1/3 the Cr of 52100, and the “B” in 50100-B indicates that the steel has been modified with V, making this a chrome-vanadium steel.
52XX: Chromium steel group. Contains 1.45% Cr. A strong yet flexible alloy.
52100: A non-stainless ball-bearing steel used only by forgers. Similar to 5160 (though it has around 1% C vs. 5160 ~0.60%), but holds an edge better. Less tough than 5160, however. Exhibits many of the same advantages as BG-42. 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.
A-2: An excellent air-hardening tool steel with 5% Cr, known for its great toughness and good edge holding. Its outstanding toughness makes it a frequent choice for combat knives. Deeper hardening and more wear-resistant than O-1, and holds a keener cutting edge. More readily machined than high C, high Cr grades.
ATS-34: Japanese high carbon, high chrome/moly stainless by Hitachi. 13½-14½% Cr. Very good combination of sharpening, edge-holding, rust resistance and strength. See 154-CM. Superfine grain structure = edge holding. Rc 60-62.
ATS-55: Similar to ATS-34, but with the Mo removed and some other elements added. Not much is known about this steel yet, apparently intent was ATS-34 edge-holding with increased toughness at a lower price.
AUS-6 or 6A: Japanese medium to high carbon stainless. .65% C. Basically 440-A with added V. Tougher than ATS-34, 440-C, ATS-55, etc., but still holds a good edge. 440-C is better. Particularly well suited for heavier, longer blades that are subjected to a lot of stress while chopping and hacking.
AUS-8 or 8A: Japanese low carbon, high chromium stainless roughly comparable to 440-B. .75% C. Has some V, which 440-B lacks. Good compromise between toughness, strength, edge holding and resistance to corrosion. As heat treated by Cold Steel, won’t hold an edge like ATS-34. According to Cold Steel, the only equal to AUS-8 in strength and toughness is AUS-10.
AUS-10 or 10A: Japanese high carbon stainless roughly comparable to 440-C, with slightly less Cr. 1.1% C. Has some V, which 440-C lacks. Equal in strength and toughness to AUS 8, but has an additional 20% in edge holding ability, giving it a claimed wide performance advantage over ATS-34, ATS-55 and 440V.
BG-42: Stainless bearing steel, but will rust. BG-42 is 440-C modified with the addition of 3.5% Mo and 1.2% V for added wear resistance and hardness retention at high heats. Best(?) edge holding steel. A VIM/VAR ingot steel. The blade gains advantages in toughness and grain structure by using ball bearing steels. Has a fine grain structure and takes and holds an exceptionally sharp edge. Can be hardened to Rc 60 which will hold a thin edge. Doesn’t finish as smooth as ATS-34. Chosen for its high V content and tight carbide structure. American steel, manufactured in Latrobe, Penn. Greg Lightfoot recommends it highly. Chris Reeve has tested this steel extensively and believes it to be superior to anything else available on the market, including ATS-34. Has a higher Cr content (14½%), superior edge-holding ability, hardness and brute strength. Offers about the best balance of properties for a stainless steel - that or CPM 420V. Not as tough as some of the toughest steels here; however tougher than the stainless steels and holds an edge better. No stainless is really that tough, compared to a non-stainless tool steel like A-2 or CPM3V. Will hold an edge longer, and get sharper than 420V. Use 56-60 Rc, but starts to get brittle at 60 Rc. At 61 Rc, BG-42 is going to get sharper, but, the 420V has the advantage of working at a lower hardness. Both will offer about equal corrosion resistance-they are exceptionally pure, clean steels, and have roughly the same free Cr. Either of these steels rules over ATS-34. A bit more expensive than ATS-34.
Carbon V: High carbon, low alloy cutlery grade steel, “specially treated” with precise heat treatment to make it extra tough, with good edge holding capability. A trademarked term by Cold Steel; not necessarily one particular kind of steel, rather, it is whatever steel Cold Steel happens to be using at the time. Performs roughly between 1095-ish and O-1-ish, and rusts like O-1 as well. Rumors are that Carbon V is O-1 (unlikely) or 1095. Numerous industry insiders insist it is 0170-6. Some spark tests seem to indicate 50100-B. Since 50100-B and 0170-6 are the same steel (see below), this is likely the current Carbon V. Carbon V knives are hardened to Rc 59.
Ceramics: Usually very very brittle, and cannot be sharpened by the user; however, they hold an edge well. Not as sharp as the best steels. Kevin “Mad Dog” McClung recently came out with a ceramic composite knife blade that much tougher than the previous ceramics, tough enough to actually be useful as a knife blade for most jobs. It is also user-sharpenable, and holds an edge incredibly well. Zirconia is a material of great hardness included in ceramic used in making ceramic blades and used as grain on grinding belts for grinding knives. Böker ceramic is zircon oxide.
Cera-Titan: Titanium, ceramic & silver. Gives up a little of ceramic’s edge holding for less brittleness, but better edge holding than top stainless. Holds an edge like ceramic with toughness closer to steel.
Cobalt & Stellite 6K: A flexible material with very good wear resistance, it is practically 100% corrosion resistant. Has an edge-holding capability that far exceeds even the best of today’s stainless steels. Stellite 6K, sometimes seen in knives, is a cobalt alloy. See Talonite. (David Boye)
CPM T420V (& CPM T440V): Offer about the best balance of properties for a stainless steel-that or BG-42. Holds an edge not as long or sharp as BG-42, but better than ATS-34. Edge holding ability is said to be 2 - 3x better than 440-C at 57 - 58RC. There are a few other powder metal steels that will give similar performance but none that are measurably better at edge holding. However, it’s difficult to get the edge there in the first place. Depending on heat treatment, expect to have to work a bit harder to sharpen these steels. Works at a lower hardness. Less tough than ATS-34. Exceptionally pure, clean steel. Both high in V. 420V is CPM’s follow-on to 440V, and with less Cr and almost double the V, is more wear-resistant and may be tougher than 440V. Rc 56-57.
CPM 10V: Another CPM steel. Edge holding ability is said to be 2-3x better than 440-C at 57-58Rc. Toughness equal to M-2 and D-2, with increased wear resistance.
CPM S30V: Premium American cutlery stainless. Powder made with uniform carbide distribution structure and clean steel properties. Excellent corrosion resistance. Extremely fine grain, excellent edge retention and superb edge qualities. The V content allows for the formation of vanadium carbides resulting in edge holding that is independent of hardness. Wide range of applications depending on heat treatment. 2-3 times the pry bar strength of 154 CM. Some judge superior to ATS-34 and BG-42. Hot new steel.
Damascus: Remarkable toughness and edge quality.
Damasteel RWL34/PMC27: Made with powder metal technology and has no welds as with traditional Damascus steels. Two or more different metals in powder form are fused together with heat and pressure. Damascene steels consist of two different steel grades, welded in over a hundred layers. After etching, one of the steel grades turns dark and a beautiful pattern appears on the surface.
D1.4: Solingen stainless.
D2: High carbon, high chrome tool die steel. THE outstanding high C, high Cr tool steel for general use. The most important characteristic of this air hardening tool die steel is its resistance to wear or abrasion. “D” series steels are classed as Cold Work Tool Steels, high C, high Cr type. Very tough, but may be a little less tough than some of the other steels mentioned. Holds an edge very well, possibly better than BG-42. High impact resistance. Takes hard use well (chopping). Cuts and holds an edge better than most steels, including M-2, 1095, AUS-8, ATS-34 and VG-10. Fairly high in Cr (12%). Good corrosion resistance, but will pit and rust. Sometimes called a “semi-stainless.” Does not take a beautiful finish. Outstanding knife steel; one of the few that is “tougher than a cob” at 60-61 Rc. Can be hardened far beyond the favored 60-61 Rc. 440XH is stainless D-2.
Duratech 20-CV: Very stainless (20% Cr). Very high corrosion resistance, tough, very good edge holding.
G-2 or GIN-1: Stainless with less C and more Cr and much less Mo than ATS-34. Offers nearly the same qualities as 154-CM or ATS-34 but is slightly more corrosion resistant. Very good stainless steel. Cheaper.
H1: A high-Cr stainless which offers 100% corrosion resistance in both salt and fresh water. Tradeoff is good edge quality and good edge toughness. Good rescue/dive/emergency knife.
L-6: A band saw steel that is very tough and holds an edge well, but rusts easily. Like O-1, it is 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 desired.
M-2: High speed non-stainless steel. Very tough tool grade steel used for cutting steel. Tougher, sharper, and holds an edge better than ATS-34. High impact strength with incredible edge holding properties, but perhaps more brittle than typical premium blades. Extraordinary abrasion resistance and superb toughness. At a Rockwell hardness of 62 Rc it exhibits extreme toughness, with no signs of brittleness, and edge retention that is superior to most other blade materials. Works well at 62-66 Rc. Highly susceptible to corrosion and will rust unless properly maintained.
M-4: Chemical content nearly identical to M-2 except for 4% V instead of 2%; is capable of nearly twice the wear life.
MBS-26: Japanese oil-quenched stainless.
N690: An Austrian made stainless, comparable to 440C in performance and value. Keen edge qualities with excellent corrosion resistance.
O-1 and O-2: The most widely used general purpose oil hardening tool and die steels. Good combination of hardness and toughness. Strong, takes a very good edge, sharpens very easily. Superior edge to ATS-34 and 440-C. Very popular with forgers; has the reputation for being “forgiving.” Excellent steels that take and hold an edge superbly, and are very tough. Rusts easily. Use Rc 56-57.
RWL34: A Swedish powder metal stainless.
San Mai III: San Mai means “three layers.” Provides a superior blade with hard (higher carbon) stainless steel in the middle core/edge for a keen, long lasting edge inside two layers of tougher (lower-carbon) spring tempered stainless steel along the sides for flexibility and support. 25% stronger than AUS 8A.
Sandvik: A tool steel made in Sweden. Swedish steel has always been a premium steel for tools because the iron ore is very clean, that is, with very little sulfur or phosphorus.
Sandvik 13C-26: High carbon stainless tool steel.
Sandvik 19C27: High carbon, high chromium stainless. At 60-62 Rc the steel is highly wear resistant for edge holding and corrosion resistance.
Sandvik LV-04: Closed-die-forged high carbon stainless tool steel.
T15: A “Super High Speed Steel.” Not suitable for knives.
T5MOV: High carbon stainless.
Talonite/Stellite: A cobalt-chromium alloy formula based on Stellite, now owned by a Canadian firm. This material is many times as wear resistant as the finest knife steel, and contains no iron, which also makes it rust free and non-magnetic. Low on the Rockwell scale but excellent abrasion resistance. Will hold an edge as well as stellite; many times better than even the best stainless steels on the market today. Not hard to sharpen. Totally rust resistant and will hold surface qualities over hundreds of years of exposure to corrosive elements. Has a matrix of carbides in the alloy that give this material its performance characteristics. When the cutting edge feels dull to the touch, it will continue to cut due to the presence of the carbide matrix. Slightly softer than stainless steel, making it easier to sharpen. Ni 3% max, Si 2% max, Fe 3% max, Mn 2% max, Cr 28-32%, Mo 1.5% max, W 3.5-5.5%, C 0.9-1.4%, balance Co. See Cobalt & Stellite.
Titanium: Newer titanium alloys can be hardened near 50 Rc, and at that hardness seem to take something approaching a useful edge. Extremely rust-resistant, and non-magnetic. Slightly lighter than steel, extremely strong and resilient.
Vascowear: A very hard-to-find steel, with a high vanadium content. Extremely difficult to work and very wear-resistant. Out of production.
VG-10: Produced by a small foundry in Honshu island in Japan. An ingot steel. A good combination of “stuff” carefully blended. Cutting performance similar to ATS-34, but without quite the same brittleness and sharpening difficulties. Looks like a real winner of a steel, only seriously outperformed by carbon steels and particle stainless types. Edge holding below O-1 and D-2 on soft materials. Significantly superior to ATS-34 & 55 in corrosion resistance. In edge retention, at least as good as and often better than ATS steels. VG-10 is today’s hot new stainless steel for heavy duty folders, said to hold an edge better than ATS-34. It will certainly hold an edge better than AUS8A.
W-1: The same as W-2 except for the V content (W-1 has no V). Most files are made from W-1, also called a spring steel.
W-2: Reasonably tough and holds an edge well, due to its 0.2% V.
X15 T.N: French steel developed for jet engine ball bearings and scalpels. Superior rust resistance, with ample edge retention and an easy to maintain edge. Great for salt water environments.
XT70: Stainless, 55 Rc. (Katz)
XT80: Stainless, 59 Rc. Excellent ability to retain an edge, claimed better than 440-C or ATS-34. Probably a version of 440-C, with about 1% C and 12-14% Cr. (Katz)
Z60CDV14: A clean high carbon Swedish stainless. Higher in Ni and Mo than AUS-8, with a little less C. Good balance between ease of sharpening and edge retention.
9Cr14MoV: Chinese made steel similar to AUS-8. Value steel.
9Cr13CoMoV: Chinese made high-carbon stainless with increased Co for greater edge retention. High level of corrosion resistance. Good value.
154-CM: High carbon, high chrome/moly stainless, nearly identical to ATS-34, but possibly superior, made in USA by Crucible Steel for tough industrial applications. Also called 440-C Modified. Exceptional wear resistance. Has super-fine grain structure for excellent lasting edge sharpness. Normally hardened to around 60 Rc, it holds an edge very well and is tough enough even at that high hardness. Good all-around qualities. Great corrosion resistance, though not quite as rust resistant as the 400 series.
300 Series and “Surgical stainless”: Useless cutlery stainless.
“400 Series” Stainless: Probably 420J2 or 440-A, but there’s nothing to keep a company from using any 4xx steel, like 420 or 425-M, and calling it 400 Series Stainless.
410: Worse than 420J2
420J2: Softer, cheaper, ~0.15% carbon stainless tool steel, with Rc <53-55??
420: Lower carbon content (<0.5%) than the 440 series makes this steel extremely soft, and it doesn’t hold an edge well. Used often for diving knives, as it is extremely stain resistant. Also used often for very inexpensive knives. Outside of salt water use, it is too soft to be a good choice for a utility knife.
420HC: 420 High Carbon. Buck has ion fused some of its 420HC SS blades with titanium (or zirconium?) nitride (TiN) to produce a surface that is >80 Rc and holds an edge five times longer than standard blades. Performs well with proper heat treatment.
425-M (& 425?) & 12C27: Both are very similar to 440-A. 425-M has 0.5% C. 12C27 (0.6% C) is a Scandanavian steel used often in Finish and Norwegian knives. Cheap stainless. Soft and malleable?
440-A: Mid grade stainless. Most “plain” 440 is 440-A. Rc 56-59.
440-C: High grade (Solingen) high chromium stainless that holds edge well, not too hard to sharpen, doesn’t rust. Terrific balance of good hardness and corrosion resistance. Better than 440-A. Most popular. Use Rc 58-60.
440-C Modified: Same as 154-CM.
440-A, 440-B, 440-C: The carbon content (and hardenability) of this stainless steel goes up in order from A (.75%) to B (.9%) to C (1.2%). 440-C is an excellent, high-end stainless steel, usually hardened to around 56-60 Rc. All three resist rust well, with 440-A being the most rust resistant, and 440-C the least. A knife marked with just “440” is probably the less expensive 440-A; if a manufacturer had used the more expensive 440-C, he’d want to advertise that. Generally 440-A (and similar steels) is just good enough for everyday use, especially with a good heat treat (SOG). 440-B is a very solid performer and 440-C is excellent.
440XH: Stainless D-2.
SAE rates steel with a four-digit number. The first two digits refer to the steel “group,” the second pair to the amount of carbon present in 10ths of a percent. 1095 ~0.95% C, 52100 ~1.0% C, 5160 ~0.60% C. In the SAE system, steels with letter designations (W-2, A-2) are tool steels. In the AISI steel system, 10xx is carbon steel, any other steels are alloy steels. Ex: the 50xx series are chromium steels.
10XX, 11XX, 12XX, 15XX: The carbon steel group, a basic multi-use steel.
The 10-series; 1095 (and 1084, 1070, 1060, 1050, etc.): 1095 is the most popular for knives. 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. 1060 and 1050 are used often for swords.
1084: A good all around steel that holds an edge well when properly hardened and drawn.
1095: Sort of the “standard” carbon steel, not too expensive and performs well. Reasonably tough and holds an edge very well. Rusts easily. A simple steel, which contains only two alloying elements: ~0.95% C and 0.4% Mn. The various Kabars are usually 1095 with a black coating.
5150: Medium carbon, low alloy steel. Ideal for heat treated blades that have a very thick cross section such as tomahawks, axes, etc. Use 55-60 Rc. Extremely tough and impact resistant. (Cold Steel ‘hawks)
5160: A tough, springy steel popular with forgers, it is extremely popular now and a very high-end steel. Essentially a simple spring steel with Cr added for hardenability. 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) and large knives because of its toughness, and is also used for hard use knives (hardened up near the 60s Rc).
0170-6 & 50100-B: Different designations for the same steel: 0170-6 is the steel maker’s classification, 50100-B is the AISI designation. High C, low Cr steel with a Rc of 58. A good chrome-vanadium steel that is somewhat similar to O-1, but much less expensive. Carbon V may be 0170-6. 50100 is basically 52100 with about 1/3 the Cr of 52100, and the “B” in 50100-B indicates that the steel has been modified with V, making this a chrome-vanadium steel.
52XX: Chromium steel group. Contains 1.45% Cr. A strong yet flexible alloy.
52100: A non-stainless ball-bearing steel used only by forgers. Similar to 5160 (though it has around 1% C vs. 5160 ~0.60%), but holds an edge better. Less tough than 5160, however. Exhibits many of the same advantages as BG-42. 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.
45crittergitter
Member
Part 2
STEEL MAKEUP
By definition, steel is a combination of iron and no more than 2% carbon. Steel is alloyed with various other elements that combine to produce special properties. Once a particular alloy combination (or steel type) is selected, specific procedures are used to maximize the unique qualities required for that steel to perform. Generally speaking, the process for converting a steel alloy into a premium knife steel is heat treating.
Heat treatment is the most important stage in the evolution of an alloy into a performance knife steel. The first step in the heat treatment process is to reach a critical temperature. This temperature is held for a specific amount of time (depending on the steel being hardened) and causes the steel to become austenetized. Heat treatment is one of many factors that determine the grain size of the steel (a fine grain structure is more desirable for knife blades because it improves edge retention and enhances blade finish). Next, the steel is quenched (“O” is oil quenched, “A” is air quenched, “W” is water quenched) to achieve its maximum level of hardness. At this point, the steel is too hard and brittle for practical use and thus tempering is of key importance in bringing the steel to its ideal hardness level (different knife steels perform best at different level of hardness). Tempering also increases edge-holding and toughness properties. When tempering, it is important to understand the interaction between hardness and toughness. An increase in hardness is accompanied by an increase in yield strength and tensile strength and a decrease in impact strength and ductility. An increase in toughness is accompanied by the opposite (an increase in impact strength and ductility and a decrease in yield strength and tensile strength). Therefore, high-impact knives such as swords or machetes would benefit from a softer blade (to avoid blade breakage), while low-impact knives such as pocket knives may benefit from a harder blade (to improve edge performance). Once tempering is complete, the final hardness of the steel can be determined.
Most stainless barrel steel is slightly softer than the average chrome-moly barrel steel. Sako chrome-moly is very hard. Krieger won’t make stainless slim “sporter” contour barrels because of lack of strength at extremely low temperatures. They use chrome-moly instead. While stainless rifle barrels are as accurate as chrome-moly ones, in close-fit 1911s, the chrome-moly barrel will almost always be more accurate. - Les Baer. Chrome lined barrels offer a dramatic step up in durability, wear and corrosion resistance compared to either chrome-moly or stainless steel. However, the chroming process usually leads to a slight degradation in accuracy. - David M. Fortier
CARBON and alloy steels (non-stainless steels) are the steels most often forged. Knife steel is high-carbon, i.e., 0.95-1.5% C. Stainless steels can be forged, 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. Carbon steels are also often a little bit less of a crap shoot than stainless steels.
“STAINLESS” steels: All steels can rust. But “stainless” steels, with 13-18% Cr, have much more rust resistance than the “carbon” steels. There doesn’t appear to be consensus on what minimum Cr content 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 Cr needed; lower Cr with the right alloying elements can still have “stainless” performance.
HIGH SPEED steels are high-alloy steels containing significant amounts of W, V, and Mo. They are ideal alloys for cutting other metals, and are typically used in milling cutters, dies, taps, and bits. High speed steels have three distinguishing characteristics: excellent hardenability - high hardness is necessary for good wear resistance; good impact toughness - to withstand cutting tool applications; and the capacity for maintaining high hardness at elevated temperatures. The latter is not important in knife blades, but hardness and toughness are essential. See “Mo” below.
Carbon (C): Present in all steels, it is the most important hardening element, forming carbides of all other elements. Improves wear and abrasion resistance. Also increases the tensile strength of the steel. We usually want knife-grade steel to have more than 0.5% C, which makes it “high-carbon” steel. More than 1.5% can result in brittleness.
1. Increases edge retention and raises tensile strength
2. Increases hardness and improves resistance to wear and abrasion
Chromium (Cr): Added for wear resistance, hardenability, and (most importantly) for corrosion resistance.
1. Increases hardness, tensile strength and toughness
2. Provides resistance to wear and corrosion
Cobalt (Co)
1. Increases strength and hardness and permits quenching in higher temperatures
2. Intensifies the individual effects of other elements in more complex steels
Copper (Cu)
1. Increases corrosion resistance
2. Increases wear resistance
Manganese (Mn): An important element, manganese binds redundant oxygen and degasses the melt, aids the grain structure, and contributes to hardenability, strength & wear resistance. Reduces quenching shock. Improves the steel during the steel’s manufacturing (hot working and rolling). Present in most cutlery steel.
1. Increases hardenability, wear resistance, toughness and tensile strength
2. De-oxidizes and de-gasifies to remove oxygen from molten metal
3. In larger quantities, increases hardness and brittleness
Molybdenum (Mo): A carbide former molybdenum has the hardest carbide, prevents brittleness & maintains the steel’s strength at high temperatures. Present in many steels, and air-hardening steels (A-2, ATS-34) always have 1% or more Mo; it is what gives those steels the ability to harden in air. For steels with a higher C content, Mo imparts additional hardness and abrasive resistance. Mo is an expensive element useful for high-speed steels, and knife blades do not need to be high speed, so a very high Mo content is no advantage.
1. Increases strength, hardness, hardenability, and toughness
2. Improves machineability and resistance to corrosion
Nitrogen (N): Replaces carbon in alloy makeup, raising hardness and edge retention. Eliminates rust. Holds keen edge that work-hardens, increasing edge tensile strength and durability.
Nickel (Ni): Adds strength, hardness, corrosion resistance, and toughness
Phosphorous (P)
1. Improves strength, machineability and hardness
2. Creates brittleness in high concentrations
Silicon (Si): Contributes to strength. Like manganese, it makes the steel more sound during manufacture.
1. Increases yield and tensile strengths
2. De-oxidizes and de-gasifies to remove oxygen from molten metal
Sulfur (S)
1. Improves machineability when used in minute quantities, otherwise a pollutant
Tungsten (W): Increases wear resistance. When combined properly with Cr or Mo, W will make the steel a high-speed steel. The high-speed steel M-2 has a high amount of W.
1. Adds strength, toughness and hardenability
Vanadium (V): Contributes to strength, wear resistance, toughness and hardenability. A carbide former that helps produce fine-grained steel. BG-42’s biggest difference from ATS-34 is the addition of V. In many cold work applications, the V content of a tool steel may be used to get a rough estimate of the expected relative wear performance.
1. Increases strength, hardness, wear resistance and resistance to shock impact
2. Retards grain growth
HARDNESS
Rc (Rockwell) 55 is fairly soft, 57-59 is pretty hard (most knives), 60 is real hard, and 62-64 is custom only. Even a variation of one (1) point in Rc hardness can make a big difference in a blade’s strength and toughness, and the optimal hardness for each steel does not allow for broad deviations. Some of the newer exotic stainless steels are harder than novaculite (Arkansas - need oil), and therefore should be sharpened with diamond (need water), ceramic, aluminum oxide (Norton India), or sapphires.
Firearms tool steels, such as 4140, are usually treated to Rockwell 38C-42C. High-quality high stress parts such as hammers and sears run 42C-52C. A Nicholson file is 65C.
RUST PREVENTION
The same characteristics that make a high-carbon steel knife blade so very good, also make it rust readily. To reduce rusting, blue them. Take a new, unused knife, clean it thoroughly with acetone to remove all traces of oil, then use a good quality cold-blue solution on the blade. Repeat the process for a deeper blue, and better protection. Reasonable care and maintenance practices remain necessary, but the blade won’t stain or rust nearly as easily.
STEEL MAKEUP
By definition, steel is a combination of iron and no more than 2% carbon. Steel is alloyed with various other elements that combine to produce special properties. Once a particular alloy combination (or steel type) is selected, specific procedures are used to maximize the unique qualities required for that steel to perform. Generally speaking, the process for converting a steel alloy into a premium knife steel is heat treating.
Heat treatment is the most important stage in the evolution of an alloy into a performance knife steel. The first step in the heat treatment process is to reach a critical temperature. This temperature is held for a specific amount of time (depending on the steel being hardened) and causes the steel to become austenetized. Heat treatment is one of many factors that determine the grain size of the steel (a fine grain structure is more desirable for knife blades because it improves edge retention and enhances blade finish). Next, the steel is quenched (“O” is oil quenched, “A” is air quenched, “W” is water quenched) to achieve its maximum level of hardness. At this point, the steel is too hard and brittle for practical use and thus tempering is of key importance in bringing the steel to its ideal hardness level (different knife steels perform best at different level of hardness). Tempering also increases edge-holding and toughness properties. When tempering, it is important to understand the interaction between hardness and toughness. An increase in hardness is accompanied by an increase in yield strength and tensile strength and a decrease in impact strength and ductility. An increase in toughness is accompanied by the opposite (an increase in impact strength and ductility and a decrease in yield strength and tensile strength). Therefore, high-impact knives such as swords or machetes would benefit from a softer blade (to avoid blade breakage), while low-impact knives such as pocket knives may benefit from a harder blade (to improve edge performance). Once tempering is complete, the final hardness of the steel can be determined.
Most stainless barrel steel is slightly softer than the average chrome-moly barrel steel. Sako chrome-moly is very hard. Krieger won’t make stainless slim “sporter” contour barrels because of lack of strength at extremely low temperatures. They use chrome-moly instead. While stainless rifle barrels are as accurate as chrome-moly ones, in close-fit 1911s, the chrome-moly barrel will almost always be more accurate. - Les Baer. Chrome lined barrels offer a dramatic step up in durability, wear and corrosion resistance compared to either chrome-moly or stainless steel. However, the chroming process usually leads to a slight degradation in accuracy. - David M. Fortier
CARBON and alloy steels (non-stainless steels) are the steels most often forged. Knife steel is high-carbon, i.e., 0.95-1.5% C. Stainless steels can be forged, 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. Carbon steels are also often a little bit less of a crap shoot than stainless steels.
“STAINLESS” steels: All steels can rust. But “stainless” steels, with 13-18% Cr, have much more rust resistance than the “carbon” steels. There doesn’t appear to be consensus on what minimum Cr content 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 Cr needed; lower Cr with the right alloying elements can still have “stainless” performance.
HIGH SPEED steels are high-alloy steels containing significant amounts of W, V, and Mo. They are ideal alloys for cutting other metals, and are typically used in milling cutters, dies, taps, and bits. High speed steels have three distinguishing characteristics: excellent hardenability - high hardness is necessary for good wear resistance; good impact toughness - to withstand cutting tool applications; and the capacity for maintaining high hardness at elevated temperatures. The latter is not important in knife blades, but hardness and toughness are essential. See “Mo” below.
Carbon (C): Present in all steels, it is the most important hardening element, forming carbides of all other elements. Improves wear and abrasion resistance. Also increases the tensile strength of the steel. We usually want knife-grade steel to have more than 0.5% C, which makes it “high-carbon” steel. More than 1.5% can result in brittleness.
1. Increases edge retention and raises tensile strength
2. Increases hardness and improves resistance to wear and abrasion
Chromium (Cr): Added for wear resistance, hardenability, and (most importantly) for corrosion resistance.
1. Increases hardness, tensile strength and toughness
2. Provides resistance to wear and corrosion
Cobalt (Co)
1. Increases strength and hardness and permits quenching in higher temperatures
2. Intensifies the individual effects of other elements in more complex steels
Copper (Cu)
1. Increases corrosion resistance
2. Increases wear resistance
Manganese (Mn): An important element, manganese binds redundant oxygen and degasses the melt, aids the grain structure, and contributes to hardenability, strength & wear resistance. Reduces quenching shock. Improves the steel during the steel’s manufacturing (hot working and rolling). Present in most cutlery steel.
1. Increases hardenability, wear resistance, toughness and tensile strength
2. De-oxidizes and de-gasifies to remove oxygen from molten metal
3. In larger quantities, increases hardness and brittleness
Molybdenum (Mo): A carbide former molybdenum has the hardest carbide, prevents brittleness & maintains the steel’s strength at high temperatures. Present in many steels, and air-hardening steels (A-2, ATS-34) always have 1% or more Mo; it is what gives those steels the ability to harden in air. For steels with a higher C content, Mo imparts additional hardness and abrasive resistance. Mo is an expensive element useful for high-speed steels, and knife blades do not need to be high speed, so a very high Mo content is no advantage.
1. Increases strength, hardness, hardenability, and toughness
2. Improves machineability and resistance to corrosion
Nitrogen (N): Replaces carbon in alloy makeup, raising hardness and edge retention. Eliminates rust. Holds keen edge that work-hardens, increasing edge tensile strength and durability.
Nickel (Ni): Adds strength, hardness, corrosion resistance, and toughness
Phosphorous (P)
1. Improves strength, machineability and hardness
2. Creates brittleness in high concentrations
Silicon (Si): Contributes to strength. Like manganese, it makes the steel more sound during manufacture.
1. Increases yield and tensile strengths
2. De-oxidizes and de-gasifies to remove oxygen from molten metal
Sulfur (S)
1. Improves machineability when used in minute quantities, otherwise a pollutant
Tungsten (W): Increases wear resistance. When combined properly with Cr or Mo, W will make the steel a high-speed steel. The high-speed steel M-2 has a high amount of W.
1. Adds strength, toughness and hardenability
Vanadium (V): Contributes to strength, wear resistance, toughness and hardenability. A carbide former that helps produce fine-grained steel. BG-42’s biggest difference from ATS-34 is the addition of V. In many cold work applications, the V content of a tool steel may be used to get a rough estimate of the expected relative wear performance.
1. Increases strength, hardness, wear resistance and resistance to shock impact
2. Retards grain growth
HARDNESS
Rc (Rockwell) 55 is fairly soft, 57-59 is pretty hard (most knives), 60 is real hard, and 62-64 is custom only. Even a variation of one (1) point in Rc hardness can make a big difference in a blade’s strength and toughness, and the optimal hardness for each steel does not allow for broad deviations. Some of the newer exotic stainless steels are harder than novaculite (Arkansas - need oil), and therefore should be sharpened with diamond (need water), ceramic, aluminum oxide (Norton India), or sapphires.
Firearms tool steels, such as 4140, are usually treated to Rockwell 38C-42C. High-quality high stress parts such as hammers and sears run 42C-52C. A Nicholson file is 65C.
RUST PREVENTION
The same characteristics that make a high-carbon steel knife blade so very good, also make it rust readily. To reduce rusting, blue them. Take a new, unused knife, clean it thoroughly with acetone to remove all traces of oil, then use a good quality cold-blue solution on the blade. Repeat the process for a deeper blue, and better protection. Reasonable care and maintenance practices remain necessary, but the blade won’t stain or rust nearly as easily.
AStone
Member
45CG, these are really useful overviews.
I've been wanting to read something like this.
Thanks very much for posting them.
Nem
PS: for me, reading part 2 on general principles first helps me understand part 1 more easily, which deals with specifics.
YMMV
I've been wanting to read something like this.
Thanks very much for posting them.
Nem
PS: for me, reading part 2 on general principles first helps me understand part 1 more easily, which deals with specifics.
YMMV
45crittergitter
Member
Thanks, and you're welcome. Just a compilation of stuff I've gathered over the years from various knife catalogs, magazine articles, etc.
TimboKhan
Member
Good stuff, 45CG.
Bikerdoc pretty much hit the nail on the head about asking questions. My knowledge of steels and the properties thereof is pretty minimal, but by asking questions and getting either direct answers or tips on where to find my answers, I am coming along nicely.
As a soapbox moment, it's information like this that has kept me on THR for so long with no particular end in sight. We all here about not believing stuff that you get off the net or forums, but the often ignored fact is that there is an awful lot (and I mean a lot) of good knowledge out there, just waiting to be shared.
Now, go buy a Glock.
Bikerdoc pretty much hit the nail on the head about asking questions. My knowledge of steels and the properties thereof is pretty minimal, but by asking questions and getting either direct answers or tips on where to find my answers, I am coming along nicely.
As a soapbox moment, it's information like this that has kept me on THR for so long with no particular end in sight. We all here about not believing stuff that you get off the net or forums, but the often ignored fact is that there is an awful lot (and I mean a lot) of good knowledge out there, just waiting to be shared.
Now, go buy a Glock.
45crittergitter
Member
FYI, although the common ATS-34 and 154-CM are excellent knife steels, in my personal experience D2 is far better and I do pay extra to get it.
- Status
