I wish I knew more about O1, I've never had much opportunity to work with many O1 blades myself... <img src="/ubbthreads/images/graemlins/blush.gif" alt="" />
I wonder why none of the mainstream manufactures use it for anything... <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> Sounds like a great tool/blade steel to me. <img src="/ubbthreads/images/graemlins/cool.gif" alt="" />
Found some more info and the only reason I can see according to this is that 1095 is slightly cheaper ! As for me personally I have had knives made from 1095, 01, SR77,SR101,D2,A2,Aus8,and some others that slip my mind and without a doubt I have found the Swamprats SR101 to be the best performer. I would even take SR101 over INFI on everything except a chopper !
Here is the other info:
O1 Oil hardening high alloy tungsten-vanadium tool steel is a highly underrated yet superb oil-hardening cold work tool and die steel and is a high alloy tungsten-vanadium tool steel that can be made tough, hard, and extremely sharp and wear resistant. Note that not all O-1 by all manufacturers has the same alloy content! Some versions contain no vanadium whatsoever, and those versions of the alloy do not benefit from the advantage of vanadium carbides that increase wear resistance. The O-1 in a a tungsten-vanadium version, has high wear resistance. It’s fairly easy to work in the annealed state, so prices can be kept reasonable. Polishing it is difficult, and requires a different regime than the stainless tool steels. O-1 will rust if not cared for, but it’s a great steel, maintains an incredibly sharp, fine edge and is relatively easy to sharpen in the field.
Plain carbon (standard) steels: These are the typical steels used by many knife makers and are classified in the Machinists’ Guide as Standard Carbon Steels, is steel where the main alloying constituent is carbon These are steels like 1095 and 5150 that are fairly common on hand-forged knives. They are used because they can be hand-forged and have a relatively low critical temperature and are easy and forgiving to work with. There are better alloy steels on the market that will offer increased wear resistance, increased corrosion resistance, and higher toughness at a higher hardness than plain carbon standard steels.
Steel with a low carbon content has properties similar to iron. As the carbon content rises, the metal becomes harder and stronger but less ductile and more difficult to weld. In general, higher carbon content lowers the melting point and its temperature resistance. Carbon content influences the yield strength of steel because carbon atoms fit into the interstitial crystalline lattice sites of the body-centered cubic (BCC) arrangement of the iron atoms. The interstitial carbon reduces the mobility of dislocations, which in turn has a hardening effect on the iron. To get dislocations to move, a high enough stress level must be applied in order for the dislocations to “break away”. This is because the interstitial carbon atoms cause some of the iron BCC lattice cells to distort.
Tool steel refers to a variety of carbon and alloy steels that are particularly well-suited to be made into tools. Their suitability comes from their distinctive hardness, resistance to abrasion, their ability to hold a cutting edge, and/or their resistance to deformation at elevated temperatures (red-hardness). Tool steel is generally used in a heat-treated state.
With a carbon content between 0.7% and 1.4%, tool steels are manufactured under carefully controlled conditions to produce the required quality. The manganese content is often kept low to minimize the possibility of cracking during water quenching. However, proper heat treating of these steels is important for adequate performance, and there are many suppliers who provide tooling blanks intended for oil quenching.
Tool steels are made to a number of grades for different applications. Choice of grade depends on, among other things, whether a keen cutting edge is necessary, as in stamping dies, or whether the tool has to withstand impact loading and service conditions encountered with such hand tools as axes, pickaxes, and quarrying implements. In general, the edge temperature under expected use is an important determinant of both composition and required heat treatment. The higher carbon grades are typically used for such applications as stamping dies, metal cutting tools, etc.
Tool steels are also used for special applications like injection molding because the resistance to abrasion is an important criterion for a mold that will be used to produce hundreds of thousands of parts.
Cold-working grades
Grade-O refers to oil hardening tool steels, while grade-A refers to air hardening tool steels. These tool steels are used on larger parts or parts that require minimal distortion during hardening. The use of oil quenching and air hardening helps reducing distortion as opposed to higher stress caused by quicker water quenching. More alloying elements are used in these steels, as compared to water-hardening grades. These alloys increase the steels’ hardenability, and thus require a less severe quenching process. These steels are also less likely to crack and are often used to make knife blades.
Composition
Here are composition for some of the most common cold-working tool steels, quantities of minor ingredients may vary slightly with manufacturer:
O-1 steel contains
0.90% carbon
1.0%–1.4% manganese,
0.50% chromium,
0.50% nickel, and 0.50% tungsten.
1095 steel contains 0.95% carbon, 0.40% manganese.
This series of tool steels exhibit the following characteristics, ranging from 1095 to 1050 in descending order: more carbon to less carbon; best edge holding to better edge holding to good edge holding; and tough to tougher to toughest.
ELEMENTS OF STEEL
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 but, added in isolation, decreases toughness. 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 typically deemed “stainless” steel, though another definition says the steel must have at least 11.5% free chromium (as opposed to being tied up in carbides) to be considered “stainless”. Despite the name, all steel can rust if not maintained properly. Adding chromium in high amounts decreases toughness. Chromium is a carbide-former, which is why it increases wear resistance.
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 A2, 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., A2, ATS-34) always have 1% or more molybdenum — molybdenum is what gives those steels the ability to harden in air.
Nickel
: Adds toughness. Present in L-6 and AUS-6 and AUS-8. Nickel is widely believed to play a role in corrosion resistance as well, but this is probably incorrect. Nickel is what allows stainless steel to be used as surgical steel.
Surgical stainless steel is a specific type of Stainless steel used in medical applications. Chromium gives the metal its scratch-resistance and Corrosion resistance. The Nickel provides a smooth and polished finish. The Molybdenum gives greater hardness, and helps maintaining a cutting edge.
Although there are myriad variations in the recipes, there are two main varieties of stainless steel: Martensite and Austenite.
The word ’surgical’ refers to the fact that these types of steel are well-suited for making surgical instruments: they are easy to clean and Sterilize. Immune system reaction to nickel is a potential complication. In some cases today Titanium is used instead in procedures that require a metal implant which will be permanent. Titanium is a reactive metal, the surface of which quickly oxidizes on exposure to air, creating a microstructured stable oxide surface. This provides a surface into which bone can grow and adhere in orthopaedic implants but which is incorrodible after implant. Most surgical equipment is made out of Martensite steel as it is much harder than Austenite steel, and easier to keep sharp. Nickel keeps the microscopic craters in the surface of steel to a minimum to reduce bacterial and viruses from lodging on the surface.
Phosphorus
: Present in small amounts in most steels, phosphorus is a essentially a contaminant which reduces toughness.
Silicon
: Contributes to strength. Like manganese, it makes the steel more sound while it’s being manufactured.
Sulfur
: Typically not desirable in cutlery steel, sulfur increases machinability but decreases toughness.
Tungsten
: A carbide former, it 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 M2 has a high amount of tungsten. The strongest carbide former behind vanadium.
Vanadium
: Contributes to wear resistance and hardenability, and as a carbide former (in fact, vanadium carbides are the hardest carbides) it contribute to wear resistance. It also refines the grain of the steel, which contributes to toughness and allows the blade to take a very sharp edge. A number of steels have vanadium, but M2, 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.
Typical applications for various carbon compositions are:
· 0.60–0.75% carbon: machine parts, chisels, setscrews; properties include medium hardness with good toughness and shock resistance.
· 0.76–0.90% carbon: forging dies, hammers, and sledges.
· 0.91–1.10% carbon: general purpose tooling applications that require a good balance of wear resistance and toughness, such as drills, cutters, and shear blades.
· 1.11–1.30% carbon: small drills, lathe tools, razor blades, and other light-duty applications where extreme hardness is required without great toughness.
0170-6 – 50100-B
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. 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. I do hope you know that all steels are just compromises made with different concessions for different applications.
1095 is a standard cutlery steel. It is not as springy as 5160, but that same trait allows 1095 a better, sharper edge. Making 5160 a better chopper and 1095 a better cutter. 0170-6 is like an improved 1095, with the addition of some other elements, most notably vanadium. this is like splitting the difference, properties-wise between 1095 and 5160. It is probably more impact resistant than the simpler steel, but not a notable as 5160 spring steel.
Following by Terry Barry
“I do know that a more precise hardening regime exists with 01 and that is the main reason it’s used in fine tool making. For me the beauty of 01 is that it’s a most forgiving steel by being easy to work, takes a nice polish and heat treats very precisely. It is the best of all high carbon tool steels.
Though it is more expensive that any of the 100 series, it is also more readily available here. People who do forging, like the 100 series metal as they like to differentiate the hardening process and play around with Hamon lines to make the blade look special. In reality, it’s all acedamic about which steel is better than the other. For instance, spring steel makes a really good blade but doesn’t hold an edge as well as HC steel, neither does 440C.
For blade applications, most steel that has higher than normal carbon, is great. I like D2 but it’s as hard as the hobbs of hell to work in it’s annealed stage. Being a die steel, that’s understandable but how many knives will ever be put through the torture of doing high temp. Industrial die work … none. As I said, it’s all acedamic. However, I have noticed over the years a nice steady return to HC steels and away from the 400 series stainless in custom work.”
Following by Brian Johnson
“I think it’s mostly a matter of cost. They are both similar in overall composition but 1095 is a little bit cheaper than O1. O1 is held to a little bit tighter tolerances (and therefore more predictable) during manufacturing. It also contains small amounts of silicon (helps keep things stable in manufacturing), tungsten (for wear resistance), chromium (deeper hardenability and better wear resistance), and vanadium (refines the grain and adds wear resistant carbides).
O1 also responds better to marquenching. Marquenching allows me to extract the absolute maximum performance from the steel. If you were to austenize both steels in a forge and quench in a bucket of oil, there would probably be no noticeable performance difference between the two. 1095 is slightly easier to machine since it does not have any alloying agents besides carbon and manganese, but this is almost irrelevent except in high volume mass-production. Overall, they are both good choices for hard-use blades as long as they are heat treated correctly.
