But if you allow the part to cool normally and then cryo treat it, it does zip/nada/nil/nothing etc
I won't bore you with too much science, but I like to verify claims before I make them. Before i bought into the
Cryo-REM process, I took some samples to work and tested them. First up was a stock Honda transmission gear.
I performed a hardness test using a Brinell tester and came up with a value of 364 HB which roughly corresponds
to hardened 4340 low alloy steel. So now I knew what the gears were made of and had a baseline for comparison.
Next part was the same kind of gear that had been treated to DCT subsequent to manufacturer. This gear tested
384 HB, a 5.5% increase in hardness over the stock gear. That's a significant amount. I also examined the gears
using the Xray diffraction 6 line method and discovered a marked reduction in austenite in the DCT gear. This
suggest the metal was changed at the molecular level - so much for "zip/nada/etc". Oh and by the way, as should
be the case with any experiment, I tested a half dozen different gears - treated and untreated, to minimize
production variations effects on my results. So the numbers I posted are averages.
I'm guessing from your comments you are a machinist and your experience with this process (if any), is confined
to SCT (shallow cryogenic treatment). The difference between that and DCT (deep cryogenic treatment), are
significant. With SCT, a part is cooled to 193K, removed and simply allowed to warm to room temperature. With
DCT, the part is cooled all the way down to 77K, kept at that temperature for a lengthy time and then warmed up
slowly using a controlled schedule.
dogger