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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
I didn't know that anyone still uses double edged blades.
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.
https://www.youtube.com/watch?v=hAxi5YXTjEk
[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,
I wouldn't know about cold tempering, but I do know that steel can become very brittle in cold temperatures
The Titanic...Quote:
Originally Posted by Frank S
We had a contract to machine and fabricate some fixtures to be used in the Artic circle We had to provide coupons for Tensile, bend, notch, and cold saturation testing using several different brands and types of fillers and different heat settings on our welding machines. Just because a Filler manufacture provided Sharpie stats didn't always mean it would pass the -40° required test. I found 2 brands of .045 dual shield wire that would exceed the manufacture's spec sheet. the Hobart Excell 550 and Trimark 777.