Sub-zero / Cryogenic Treatment Quench, cool and then freeze immediately after hardening and before tempering. Remove from cryo and allow blade to warm to room temperature in ambient air.
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What is cryogenic cold treatment of steel?
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What happens in the cryogenic heat treating process?
Sep 25, 2020 · The Cryogenic, sub-zero, deep freezing or cold treatment of steel is nothing more than taking the steel and freezing it. This step is always done after austenitizing and quenching the blade. Please do not perform a Cryogenic Quench by plunging a hot (austenising temperature) blade into a super chilled quench medium ( Liquid nitrogen ).
How does cryogenic processing increase knife toughness?
May 12, 2021 · This step primes the material at a molecular level to form a crystalline structure. After heat treatment, the material is brought back to room temperature to cool. Drop the temperature during cryogenic treatment: After the material has been resting at room temperature, it’s then brought down to minus 300-310 degrees Fahrenheit. Reducing material to this extreme …
Do you heat treat your knives?
Aug 11, 2021 · Heat treatment is one of the ways those imperfections are fixed, but even after heat treatment the steel can still be anywhere from 15-20% austenite, leaving it more brittle that the steel is capable of. ... Is Cryogenic Processing Making Your Knife Better. In theory, yes. But like everything with a complex craft, it depends on the materials ...
What does Cryo treating a knife do?
Cryogenic treatment is a common process designed to enhance the performance of metal blades. Extreme deep freezing increases the service life of knives by improving their resistance to wear. As a one-time treatment, freezing knife blades makes them more durable and less prone to chipping and fracturing under stress.
How do you perform a cryogenic treatment?
Cryogenic hardening is a cryogenic treatment process where the material is slowly cooled to very low temperatures. By using liquid nitrogen, the temperature can go as low as −196 °C. It can have a profound effect on the mechanical properties of certain materials, such as steels or tungsten carbide.
Can you quench a blade in liquid nitrogen?
Please do not perform a Cryogenic Quench by plunging a hot (austenising temperature) blade into a super chilled quench medium (Liquid nitrogen). The word “quench” as it relates to cryogenic treatments is misleading and should not be used.Sep 25, 2020
How do you heat treat a knife at home?
To soften the steel and relieve built-up stresses, you need to immediately heat it up again - this time to 400℉. This process, known as tempering, can be done over a fire or using a blowtorch, but the simplest method is to put it in your oven at 400℉ for two one-hour cycles, letting the knife cool between each one.Feb 2, 2021
What does cryogenics do to steel?
Cryogenic hardening is able to make metal objects and workpieces more resistance to wear and tear. Metal doesn't just become harder through cryogenic hardening; it becomes tougher and more resistant to wear. As a result, cryogenic hardening is performed to increase the usable life of metal objects and workpieces.Jul 16, 2019
What temp is cryogenic?
The cryogenic temperature range has been defined as from −150 °C (−238 °F) to absolute zero (−273 °C or −460 °F), the temperature at which molecular motion comes as close as theoretically possible to ceasing completely.
What is nitrogen quenching?
Nitrogen quenching is a type of inert gas quenching that uses a cost-effective medium that can be generated on-site. PSA and membrane nitrogen generators can be used for industrial nitrogen gas production, eliminating the need for the transportation and storage of compressed gas cylinders.Mar 10, 2020
How can I buy liquid nitrogen?
Search online for a liquid nitrogen distributor near you, like Praxair or Airgas. You can also ask at your nearest university, since many science departments use liquid nitrogen and may sell you some. Before you purchase liquid nitrogen, you'll need a dewar, which is a sturdy metal container for holding the liquid.
What is Sub Zero tempered steel?
Holding steel components at a temperature below zero degrees Centigrade to obtain the required structure. The temperature used is usually between -70ºC and -196ºC and the process is always followed by tempering.
Can you heat treat a knife with a propane torch?
A propane (or MAPP gas) torch played evenly along the blade will get the job done. Try to get the heat color evenly across the blade. You don't need to harden the entire knife blank. Just the blade is good enough.Dec 30, 2012
What oil do you use to heat treat a knife?
There are many food-grade quenching oil options available to use for blacksmithing. Among these options are vegetable, peanut, and avocado oil. Some commonly used vegetable oils are canola, olive, and palm kernel oil. Vegetable oil is very cheap and comes from renewable sources.Mar 28, 2020
Can you temper a knife with a torch?
0:577:17Tempering File Knife With Torch . - YouTubeYouTubeStart of suggested clipEnd of suggested clipYou know stays wet stays cool and it doesn't harden and it only it only softens the areas that I hitMoreYou know stays wet stays cool and it doesn't harden and it only it only softens the areas that I hit with the torch.
What is LIN in ice?
This step is always done after austenitizing and quenching of the blade. Liquid nitrogen ( LIN) treatments are often called “Cryogenic” or Deep Cryogenic treatments, where cryogenic refers to any temperature below (-310°F/-195°C). “Subzero” usually refers to a mix of dry ice and alcohol / acetone (-110°F/-78°C).
What happens when you use cold treatment on austenite?
Using cold treatments means you get closer to the actual Mf and “complete” the transformation.
Can austenite be tempered?
The destabilized austenite must be allowed to transform to martensite after cooling and the newly formed, brittle, un-tempered martensite must be tempered. Any cold treatments should always be followed by a tempering cycle.
Can austenite be transformed into martensite?
The colder you go the more retained austenite will be transformed to martensite. Even with household freezer temperatures about half of the unstable retained austenite was transformed, meaning even a freezer can transform some the retained austenite when heat treating tool steels.
Can you temper steel with water?
If using a cold treatment before tempering, I recommend using water to make sure the steel is fully at room temperature. Now water can be a dangerous medium to put a blade into due to cracking… So before doing so, make sure it’s at a temperature that you can safely handle the blade with your bare hands. I have 1inch thick aluminum plates that do a great job at sucking the heat out of blades.
Why can't knives withstand stress?
One of the primary reasons why a blade can’t withstand extreme, regular use is because of the lack of uniformity in the metal’s composition at the molecular level.
How do metal tools harden?
Most manufactured metal tools undergo a hardening treatment process, conventionally done through heat treatment. Cryogenic treatment is an extension of this usual process, following similar steps but adding in the controlled application of a cryogenic fluid, like liquid nitrogen. The cryogenic treatment process can vary depending on a few factors:
What metals are prone to oxidation?
Ferrous metals, like cast iron, stainless steel or steel alloys, and non-ferrous metals, like aluminum or copper, are both prone to oxidation, which increases wear. Oxidation is a chemical reaction that takes place on the metal’s surface when oxygen is present. Over time, oxidation corrodes the metal.
Why do knives need cryogenic process?
Knives and blades need to undergo and repeated use, often under high-impact and severe conditions. They need to maintain their shape, sharpness or strength. Metal becomes harder through the cryogenic process and can then stand up to significant and repetitive use for much longer .
How to improve hardness of metals?
During the manufacturing process , a standard way to improve the hardness of metals, like iron, steel, aluminum or copper, is to expose the material to extreme temperatures. Exposure to extreme heat, also called heat treatment, fundamentally alters the material at its atomic level.
What temperature is cryogenic treatment?
Cryogenic treatment goes by many other names, including cryogenic tempering, cryogenic hardening and deep cryogenic treatment (DCT), which usually indicates that the process uses temperatures below 300 degrees Fahrenheit.
Why cryogenically freezing knife blades?
1. Increases Resistance to Wear and Tear. The primary benefit of cryogenically freezing knife blades is that it increases the blades’ resistance to wear and tear. In industrial settings, maintaining and improving productivity are the primary goals.
What is duplex steel?
This is usually a very soft and corrosive resistant structure often used in cheaper kitchen cutlery. Duplex: A form of hybrid between austenitic and ferritic steels (it’s sometimes called austenitic-ferritic) that tends to be more corrosion resistant than the austenitic structure and harder than the ferritic structure.
What are the four structures of stainless steel?
The Four Stainless Steel Structures: Martensitic: A hard structure built up around the composition of iron, chromium, and carbon. This structure can be heat treated. Austenitic: A face-centric cubic structure that can not be hardened by heat treatment. Generally results from the addition of nickel, manganese, and nitrogen.
Does cryogenic treatment help with knives?
Yes, cryogenic treatment improves some types (high alloy) knife steels. It does more for long term toughness than any kind of hardness or sharpness. Probably every large knife manufacturer is doing it on some knives. No, we probably aren’t paying extra for knives as a result.
Does SOG use cryo?
SOG clearly does it on at least some of their knives since they explain the process in their buyer’s guide. Rumor has it Benchmade uses some kind of cryo process, and Spartan Blades touts their “ double deep cryo heat treatment” in most of the product descriptions of their Gold Grade knives.
Is baking a healthy analogy?
Baking always seems to make a healthy analogy to treating steel, so in this case you could think of it like baking cookies hot enough to break the sugar down, causing the dough to flatten out, then freezing the cookies to where the sugar crystalizes and makes it sweeter.
Is soft steel hard?
This is steel we’re talking about. Even soft steel is pretty damn hard, and most of us will never use our knives in a way that would make us notice the added toughness between regular steel and cryogenically treated steel.
Can steel be made tougher?
In theory, yes. But like everything with a complex craft, it depends on the materials and the application. If done right, the process should make the steel tougher, but not all steel types react to the process in the same way.
What is annealed steel made of?
Annealed steel is made up of magnetic ferrite and hardened steel is made up of magnetic martensite. Austenite forms at high temperature prior to quenching. Some knifemakers mistakenly state that when the steel is nonmagnetic that means that the Curie point has been reached, at about 1420°F.
What is the most important factor in knife performance?
1. Heat Treating is the most important factor for high performance knives. This one started out along the lines of “even the best steel will perform poorly if given a bad heat treatment,” and that I can’t disagree with too much. However, it has become somewhat fashionable to talk about knife performance as entirely (or almost entirely) controlled by the knifemaker’s skill in heat treatment. This has some truth to it as knifemakers who use a subpar heat treatment will certainly have subpar performance. However, the heat treatment can only do so much. No heat treatment is capable of making high carbide CPM 15V into a high toughness steel. No heat treatment can turn 1095 carbon steel into a stainless. And I would argue that the single most important factor for knife performance is the edge geometry rather than the steel selection or heat treatment. The edge geometry greatly controls the cutting ability and edge retention of the knife and also resistance to chipping and rolling. The image below shows measured edge retention of 154CM knives with different edge angles so you can see the vast difference in measured performance (higher number means more cardstock cut). Of course, focusing on any one of these factors at the expense of the others: steel selection, heat treatment, and edge geometry, is a mistake and each should be optimized for the given knife. But if we were to pick one factor that is the “most important” I’m not sure that heat treatment would be the one.
What temperature does steel go to Curie?
With most low alloy knife steels, the steel transforms to austenite before reaching Curie, and therefore the nonmagnetic temperature is significantly lower, usually somewhere in the range of 1350-1380°F. You can read more about Curie in this article. 10. Normalize steel by using descending temperatures.
Why is a longer hold time better for knives?
Therefore, using a longer hold time can lead to more consistent hardness both within a single knife and between different knives.
Which is easier to heat treat: low alloy steels or simple steels?
8. Simple steels are easier to heat treat. Low alloy steels are easier to harden without a soak at the hardening temperature, which facilitates hardening in a forge without temperature control. However, they are no easier to achieve good properties than high alloy steels.
What temperature is used for grain refinement?
Grain refinement can then be performed at lower temperatures, just above austenite formation such as in the range of 1375-1450°F. Lower temperatures typically mean a smaller grain size. However, the intermediate temperatures like 1500°F don’t do a particularly great job of accomplishing either of these goals.
How does steel become nonmagnetic?
There are two primary ways that a steel can become nonmagnetic: 1) transforming to the “austenite” phase, or 2) by reaching the Curie point. The Curie point is where the ferrite phase becomes nonmagnetic.
What temperature does cryo get?
Cryo is -300 F which you get from liquid nitrogen . You need LN2, an insulated dewar to keep it in, and a blade to freeze ! Temper after freezing.
What is the difference between science and art?
SCIENCE: Following what is known and proven, and disregarding what is unknown or unproven in order to achieve clear and predictable results. ART: Combining methods and techniques in ways that are not fully documented or proven in order to achieve results that are inexplicably (for now at least) positive.
