Thread: Goldegde versus Wonderedge

How does it align the crystal structure? You have jumped from them saying it changes the crystal structure to this concept of aligning the structure.

It converts more austentite to martensite making it harder.

Originally Posted by ernestrome

How does it align the crystal structure? You have jumped from them saying it changes the crystal structure to this concept of aligning the structure.

It converts more austentite to martensite making it harder.

From my understanding, you would have to re-heat and then do a controlled cooling to initiate the phase change you're describing. Granted I could be wrong as I'm just beginning my experience in materials engineering (besides, I'm actually Biomed Engineering).

However, my intuitive understanding of cryo-hardening is that it works in the same manner as stress hardening. In stress hardening, you apply (usually) tension until the material begins to plastically deform, and then return it to an unstressed state. Thus, the crystal structure becomes more aligned, some dislocations are removed, and most importantly in the future it will require a greater initial force (stress) before the material begins to deform. I will check into this further, but it stands to reason in my mind that cryo-hardening would work the same as a compressive strain hardening through similar mechanisms.

Like I said, don't quote me on this until I verify it.

Does anyone know what particular alloy of steel is used? That would help greatly in property research.

I have a Dovo #41 Fritz Bracht pre WW II Inox. That I had cryogenically hard by Texas Knife Makers Supply. It made very significant difference in this blade. It would not hold an edge until it was treated. It now performs the way I expect a Inox blade to perform.

I am not to sure what they meant when in the old days they said frozen, ice,or cold tempered...
My familiarity with Cryo-dropping has to do with rifle barrels, and the "supposed" benefits of doing the processes..
As others have posted the temperature must be lowed gradually down to -373 F the benefits are to include less harmonic vibration, better accuracy, a slicker bearing surface, more velocity, easier cleaning etc:etc:etc: there have been tests to confirm all these claims so I guess there are tangible benefits to getting metal cryo'd
I don't for a minute believe that this is what any razor manufacturer was doing though... I think it was more like the newer Dovo Ice Hardened Blades...

Originally Posted by chancecatalyst

From my understanding, you would have to re-heat and then do a controlled cooling to initiate the phase change you're describing. Granted I could be wrong as I'm just beginning my experience in materials engineering (besides, I'm actually Biomed Engineering).

However, my intuitive understanding of cryo-hardening is that it works in the same manner as stress hardening. In stress hardening, you apply (usually) tension until the material begins to plastically deform, and then return it to an unstressed state. Thus, the crystal structure becomes more aligned, some dislocations are removed, and most importantly in the future it will require a greater initial force (stress) before the material begins to deform. I will check into this further, but it stands to reason in my mind that cryo-hardening would work the same as a compressive strain hardening through similar mechanisms.

Like I said, don't quote me on this until I verify it.

Does anyone know what particular alloy of steel is used? That would help greatly in property research.

I was right... about being wrong that is. It is indeed due to further trransformation of the austenitic phase to the martensitic phase. Please ignore my previous blathering...

Originally Posted by chancecatalyst

From my understanding, you would have to re-heat and then do a controlled cooling to initiate the phase change you're describing. Granted I could be wrong as I'm just beginning my experience in materials engineering (besides, I'm actually Biomed Engineering).

However, my intuitive understanding of cryo-hardening is that it works in the same manner as stress hardening. In stress hardening, you apply (usually) tension until the material begins to plastically deform, and then return it to an unstressed state. Thus, the crystal structure becomes more aligned, some dislocations are removed, and most importantly in the future it will require a greater initial force (stress) before the material begins to deform. I will check into this further, but it stands to reason in my mind that cryo-hardening would work the same as a compressive strain hardening through similar mechanisms.

Like I said, don't quote me on this until I verify it.

Does anyone know what particular alloy of steel is used? That would help greatly in property research.

No, cryo allows retained austentite to convert to martensite.

I'm no expert, i have learned this by following the discussions of those who have expertise.

Afaik, cryo is not related or analagous to work hardening.

Thanks.

I propose a test. Somewhere amongst us there must be a Goldedge and a Wonderedge that are useless/chipped or broken/beyond repair. I'm pretty sure I could arrange some testing here at school. I don't know about tensile testing, but the key thing would be to manage to get samples under a Scanning Electron Microscope, where any hardening should be evident as a higher martensitic composition of the microstructure.

As Glenn said, I don't think they were doing controlled cooling to such drastically low temperatures for these vintage blades, but still, if there's enough of a difference that people can supposedly tell, then it should be visible in the microstructure.

Originally Posted by ernestrome

No, cryo allows retained austentite to convert to martensite.

I'm no expert, i have learned this by following the discussions of those who have expertise.

Afaik, cryo is not related or analagous to work hardening.

Thanks.

Heh, see previous post. My public display of ignorance is thus complete.

Originally Posted by chancecatalyst

I propose a test. Somewhere amongst us there must be a Goldedge and a Wonderedge that are useless/chipped or broken/beyond repair. I'm pretty sure I could arrange some testing here at school. I don't know about tensile testing, but the key thing would be to manage to get samples under a Scanning Electron Microscope, where any hardening should be evident as a higher martensitic composition of the microstructure.

As Glenn said, I don't think they were doing controlled cooling to such drastically low temperatures for these vintage blades, but still, if there's enough of a difference that people can supposedly tell, then it should be visible in the microstructure.

We'd need a few to be sure it wasn't sure to individual heat treat differences.

I haven't had the pleasure to hone or shave with a wonderedge... yet.

But my Goldedge is the best to hone and shave with.

-80s