National Cryogenics Corporation
National Cryogenics Corporation

Results & Benefits

Cryogenically treated metals and other materials show a marked increase in wear resistance without any discernable change in dimensional or volumetric integrity. Machining treated material is easier and cleaner. Redressing or regrinding treated tools removes less stock material resulting in longer tool life.

Although the material is stronger following cryogenic treatment, it shows little or no change in yield or tensile strength. The treated material becomes less brittle, without a change in original hardness. The most significant and consistent change is the increased toughness, stability and wear resistance. The Vari-Cold cryogenic process is also used extensively to relieve residual and tensile stresses.

Two main changes in the microstructure of the steel occur as a result of cryogenic treatment. These changes are the principal reasons for the dramatic improvement in wear resistance.

First, retained austenite (a softer grain structure always present after heat treatment) is transformed into the harder, more durable grain structure - martensite. The range of retained austenite in a material after heat treating may be as high as 50% or as low as 3%. The amount depends on the heat treating operator and the accuracy of the heat treating equipment. Cryogenic treatment simply continues the conversion initiated by heat treatment, whereby almost 100% of the retained austenite is converted to martensite. As greater amounts of retained austenite are transformed, and wear resistant martensite is increased, the material obtains a more uniform hardness.

Second, fine eta(n) carbide particles (precipitates) are formed during the long soak (chromium carbides, tungsten carbide, etc., depending upon the alloying elements in the steel). These are in addition to the larger carbide particles present before cryogenic treatment. These fine particles or "fillers", along with the larger particles, form a denser, more coherent and much tougher matrix in the material.

The surface energy of martensite is higher than the surface energy of austenite due to the differences in their atomic structures. In potential adhesive wear situations, the martensite is less likely to tear out than is austenite. The probability of wear particles forming in a steel in which the austenite has been transformed to martensite is less than for the steel containing some retained austenite. The adhesive wear coefficient is decreased, and the wear rate is decreased. For cryogenically treated tool steel, some of the junctions that would break off and form a wear particle if the steel were untreated, simply shear at the junction interface. In abrasive wear situations, both the martensite formation and the fine carbide formation work together to reduce wear. The additional fine carbide particles help support the martensite matrix. This makes it more difficult to dig out lumps of the material.

When a hard asperity or foreign particle is squeezed onto the surface, the carbide matrix resists plowing and wear is reduced. This is analogous to the fact that concrete made with cement, gravel (large particles) and sand (fine particles) is more resistant to wear than concrete made with cement and gravel alone.

Almost any kind of tool steel or dynamic part, for whatever application, will exhibit some kind of life increase. As less tools, or parts are needed, there is substantial savings in dollars. Additional savings include less downtime and short runs, less maintenance and change-over, which allows for lower production costs.


In fact, our Cryo-Processing treatment exceeds other heating and freezing methods by 200 to 400 percent.
See the chart below for some wear improvement data after conventional heat treatment - sub zero - versus cryogenic treatment:

AISI #

Description

At -110° F
(-80°C)

At -310°F
(-196°C)

D-2

S-7

52100

O-1

A-10

M-1

H-13

M-2

T-1

CPM-10V

P-20

440

430

303

8620

C1020

AQS

T-2

Hi carbon / chromium die steel

Silicon tool steel

Standard steel

Oil hardening cold work die steel

Graphite tool steel

Molybdenum high-speed steel

Chromium / moly hot die steel

Tungsten / moly high-speed steel

Tungsten high-speed tool steel

Alloy steel

Mold steel

Martensitic stainless

Ferritic stainless

Austenitic stainless

Nickel-chromium-moly alloy steel

Carbon steel

Graphitic cast iron

Tungsten high speed steel

316%

241

195

221

230

145

164

117

141

94

123

128

116

105

112

97

96

72

817%

503

420

418

264

225

209

203

176

131

130

121

119

110

104

98

97

92

RF Barron study results, Louisiana Polytechnic Institute

 

The following statistics shows increase in tooling performance after using National Cryogenics's Vari-Cold process:

Company

Location

Material

Improvement

 

 

 

 

Cheeta Machining Ltd.

Edmonton, Alberta

Keyway Broaches, Taps

100-150%

Redwood Plastics

Edmonton, Alberta

Carbide Saw Blades

150-200%

TPS Machine

Nisku, Alberta

Carbide Center Drills

350-400%

Petro-Chem Fabricators

Edmonton, Alberta

Roto-Broaches

100-150%

Vancouver Gear Works

Richmond, British Columbia

Gear Cutters, Coated Hobs

100-150%

RS Machine and Mfg. Ltd.

Nisku, Alberta

End Mills

100-200%

CentralWeb Color Press

Edmonton, Alberta

Guillotine Knives

100-150%

Millar Western Sawmill

Boyle, Alberta

Chipper Knives

100-150%

Karnin Machine Co. Ltd.

Edmonton, Alberta

End Mills, Taps, H/S Drills

100-150%

Venture Well Control

Edmonton, Alberta

8620 Slip Inserts

100%

Argus Machine Co. Ltd.

Edmonton, Alberta

Stock H/S Tool Steel

400%

Canada Culvert

Edmonton, AB

Mill Saw Blades

200-300%

Canada Culvert

Edmonton, AB

Spot Welder Tips (electrodes)

500%

 

Contact Us:


Through our contact us page, send us an email: Info at NationalCryogenics.com or phone us (Edmonton, AB) 1-780-405-2515 or (Houston, TX) 1-832-690-2717.

 

See Also:

Contact Us Today!

National Cryogenics

Edmonton, AB, Canada

Phone: +1-780-405-2515

Email us!

 

Houston, TX, USA

Phone: +1-832-690-2717

Email us!

 

 

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