Cryogenic treatment of drill bits: tested 2X lifetime and microstructure analysis

I bought some HSS stub drills, and treated half of them with liquid nitrogen, which improved their wear resistance dramatically. I also look at the change in microstructure with an electron microscope.

Performance of cryogenically treated M35 HSS drills - http://sci-hub.tw/10.1007/s00170-011-3616-8
Performance of cryogenically treated HSS tools - http://sci-hub.tw/10.1016/j.wear.2006.01.017
Effects of Cryogenic Treatment on the Strength
Properties - http://sci-hub.tw/10.1088/1757-899X/229/1/012014

LN2 generator video: https://www.youtube.com/watch?v=7PWESWqhD8s
Heat treatment of steel video: https://www.youtube.com/watch?v=ulfCxDsVTWo

Source of drill bits: https://www.mcmaster.com/catalog/125/2508

Temperature logger (discontinued, unfortunately): https://www.adafruit.com/product/3081

3M fine polishing pads: https://www.amazon.com/Tri-M-Ite-Polishing-Abrasive-Assorted-Sheets/dp/B07CP9CCH4/

Delorean patent on cryogenic torsion bar: https://patents.google.com/patent/US4378658

Steel grain structure inspection, and overall great channel for material analysis: https://www.youtube.com/watch?v=UuHofNW40Yw

Steel grain structure video: https://www.youtube.com/watch?v=0SIr2sBHxA4


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