Razor blade cryogenic tempering - GIF
Razor blade cryogenic tempering.
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Previously:
1920's razor blade sharpener restoration - GIF
Hook razor blades in an oscillating tool - video
Why shaving razors go dull - video
Wire stripper from double edged razor - GIF
Cryogenic machining - GIF and video
Cryogenic treatment is well documented in the literature
[QUOTE=nova_robotics;251130]Applied Science did an amazing video on cryogenic heat treatment. For the life of me I cannot envision how improved material properties are achieved. It goes against everything I know about grain structure and heat treatment. Anyway, very cool nonetheless.
The Youtube video description points to a couple of references that describe in detail what happens to the microstructure of HSS when cooled to liquid nitrogen temperature.
The retained austenite (soft material) content is significantly reduced relative to quenching at room temperature only, and carbide precipitation is tripled. In addition, the carbide precipitates are reduced in size.
Cryogenic treatment is expensive which is probably why it is not widely used,