Some knifemakers apply a ‘ cryo treatment’ to their blades before tempering. The steel is soaked overnight in dry ice or liquid nitrogen in temperatures ranging from -90℉ to -290℉, depending on the medium used.
What is the cryogenic treatment of steel?
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.
Is cryro the best heat treatment for chef knives?
As the blade is at the heart of a high-performing knife, I wanted to find the best possible heat treatment for my knives and “Cryro” seemed to be a worthwhile add-on step to achieve just that. With the thin edges on chef knives, good edge retention and high hardness is needed to handle the thinner edge geometry and prevent edge rolling.
Can I do a cryogenic quench with a hot blade?
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 ). The word “quench” as it relates to cryogenic treatments is misleading and should not be used.
Should you heat-treat your steel knives or not?
This allows the steel to undergo the transformations that it needs to and relieve stress. If your end goal is to eliminate excessive amounts of retained austenite and to obtain the steel’s maximize hardness, introducing a cold treatment into your heat-treating regime is a valid and worthwhile step for the knifemaker.
What is cryogenic heat treatment?
Cryogenic processing is a special type of heat-treating process that involves cooling heat-treated steels and other metals to temperatures lower than -300°F. The deep chilling of heat-treated parts allows the metal molecules to be brought to “cryogenic stillness” to improve wear characteristics.
What does heat treatment do to knives?
The purpose of heat treating a knife is to harden the steel sufficiently for use. The correct degree of hardness will depend on the blade's intended purpose. It needs to be hard enough to maintain its edge yet flexible enough to endure regular and sometimes intense use.
How do you treat Cryo steel?
To perform cryogenic hardening, metal is first exposed to heat using a conventional heat treatment process. Next, the metal is slowly cooled using liquid nitrogen. Once the metal is submerged or otherwise exposed to liquid nitrogen, its temperature begins to drop.
Do knives need to be heat treated?
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What can go wrong during heat treatment?
MOST OF THE PROBLEMS in heat- treated parts are attributed to faulty heat- treatment practices (such as overheating and burning, and nonuniform heating and quench- ing), deficiency in the grade of steels used, part defect, improper grinding, and/or poor part design.
When should you heat treat a knife?
To reduce the brittleness, the material is tempered, usually by heating it to 175–350°C (347–662°F) for 2 hours, which results in a hardness of 53–63 HRC and a good balance between sharpness retention, grindability and toughness.
Why cryogenic treatment is done?
A cryogenic treatment is the process of treating workpieces to cryogenic temperatures (i.e. below −190 °C (−310 °F)) in order to remove residual stresses and improve wear resistance in steels and other metal alloys, such as aluminum.
What does cryogenic do?
Cryotherapy, or cryogenic therapy, is any form of treatment using freezing or near-freezing temperatures. This can include cryosurgery, or cryoablation, where liquid nitrogen is applied locally to destroy abnormal cells (such as tumors or cancerous cells).
How long does it take for cryogenic hardening to occur?
Typical cryogenic treatment consists of a slow cool-down of -5 °F per minute (-3°C per minute) from ambient to -320 °F (-196°C), a soak for 24 to 72 hours, and warm up to ambient temperature.
How much does it cost to heat treat a knife?
Heat Treat Prices: 1-9 Blades = $10.00/pc. 10-19 Blades = $8.00/pc. $20+ Blades = $6.00/pc.
What oil do you quench a blade in?
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.
Do you quench after tempering?
Tempering is most often performed on steel that has been heated above its upper critical (A3) temperature and then quickly cooled, in a process called quenching, using methods such as immersing the hot steel in water, oil, or forced-air.
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.
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.
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.
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 .
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 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:
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.
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 cryogenic treatment?
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.
What is the process of heat treating knives?
Heat treating is a part of the knife making process that is designed to help harden the steel of the blade for use . Heat treating can be accomplished in four steps: normalize, quench, temper, and sand.
Why heat treat a knife?
The purpose of heat treating a knife is to harden the steel sufficiently for use. The correct degree of hardness will depend on the blade’s intended purpose. It needs to be hard enough to maintain its edge yet flexible enough to endure regular and sometimes intense use. At Red Label Abrasives, we take pride in providing knifemakers with ...
What can I use to quench a knife blade?
You can use metal coffee cans, a cookie tin, or something similar. Oil for quenching.
How long does it take for a forge to harden?
For the blade to harden, it needs to cool below 900℉. Wait about 10 to 15 seconds before pulling the blade out and checking it for warping.
What grit sandpaper should I use for a forging blade?
The forging process in particular causes the carbides to bunch up and become oversized, which can prevent it from properly holding an edge. Use a sheet of P150-gri t sandpaper to dull the blade edge and minimize the possibility of warping or cracking during treatment.
How to prevent air bubbles in steel?
After heating, quickly plunge the steel into a can of oil and move it back and forth in a slicing motion. This helps to prevent air bubbles from forming around the steel. Then lay it on the regulator block, which should be submerged in the oil. (The block ensures that both sides of the blade are evenly cooled.)
How to soften steel?
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.
