Greg, the following is from CFI in Florida, for what it's worth:
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"By extending the standard heat and quench cycles of conventional metallurgical practice to the cryogenic reaches of the temperature scale, certain desirable structural changes are induced in alloys commonly used in industrial applications. Controlled thermal cycling between +400ºF and -310ºF markedly improves the wear life of steel and cemented carbide tooling and wear parts. Cryogenic processing, performed after conventional heat treating, enhances tool life by three known mechanisms:
The conversion of significant amounts of retained austenite to martensite.
The formation of fine carbide particles.
The relief of residual stresses.
Applications
Steel cutting tools, cobalt & non cobalt-bearing HSS, uncoated or TiN or chrome coated: DRILLS - END MILLS - HOBS - BROACHES - REAMERS - TAPS - CHASERS - FORM TOOLS - SAWS - ROUTERS - PIERCING TOOLS - SLITTERS - KNIVES - etc.
Cemented carbide tools, coated or uncoated: INSERTS - SOLID CARBIDE DRILLS, END MILLS, REAMERS - PIERCING TOOLS - CARBIDE TIPPED CUTTERS & SAWS - etc.
Copper alloy resistance welding electrodes
Wear parts and forming tools: CAM - BEARINGS - HOBS - THREAD ROLLS - TABLETING PUNCHES - MOLDS
Stress relieve ferrous and non-ferrous castings and forgings for enhanced dimensional stability and surface finish upon final machining.
The Benefits
Dramatically reduce consumption of perishable tooling. Treated tools typically yield two to five times the production of non-treated tools before regrinding is required.
Cryogenic treatment will result in the permanent volumetic enhancement of metal properties. Treated components may be ground after treatment and the benefits of treatment are retained.
Reduce the frequency and cost of tool regrinding. Worn treated tools require less material removal to restore a uniform cutting edge. Hence, treated tools may be reground more times before falling below minimum acceptable dimensions. This represents yet an additional cost savings.
Substantially reduce machine downtime attributable to tool replacement.
Reduce the scrap rate for machined forgings and castings by cryogenically treating prior to final machining for better stability and surface finish.
Cryogenic processing, enhancing the wear resistance of steel and cemented carbide, chromium or TiN coated tools and wear parts, and copper resistance welding electrodes;
Dimensionally stabilize metal optics and precision ground parts prior to final polishing/grinding to produce a superior surface finish;
Stress relieve forgings and casting to ensure dimensional stability during final machining;
Dimensionally stabilize nylon components;
Stress relieve metals for tear-free drawing."
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For what it's worth. It would be nice to see some real world results from identical knives with identical steels.