Vermiculite Annealing.

[Larrin]

The slower the cooling, the coarser the pearlite/carbides, and the lower the hardness.

 

[Stacy E. Apelt - Bladesmith]

Really, I learned it the opposite. Very slow cooling produces fine pearlite.
Here is an excerpt from a paper on pearlite:
An extremely fine, fully pearlitic structure with an interlamellar spacing of 30–50 nm has been obtained during continuous cooling transformation at a rate as low as 0.1 °C s−1,

 

[DeadboxHero]

Really, I learned it the opposite. Very slow cooling produces fine pearlite.
Here is an excerpt from a paper on pearlite:
An extremely fine, fully pearlitic structure with an interlamellar spacing of 30–50 nm has been obtained during continuous cooling transformation at a rate as low as 0.1 °C s−1,

Stacy, Do you have the rest of the paper?

 

[DeadboxHero]

"Fe–1C–1.5Si–1.9Mn–1.3Cr–0.25Mo wt.%. During the course of experiments on the transformation of austenite
under the influence of a 30 tesla magnetic field, it was discovered that the continuous cooling transformation of austenite at 1 °C s-¹ resulted in the development of pearlite with an interlamellar spacing of just 50–100 nm,

whereas the pearlite was not present in the absence of the field"


"The purpose of the work presented here was to see whether the fine pearlite could be obtained by enhancing the driving force using alloying elements rather than an externally applied magnetic field."


The slow cooling doesn't work for making fine pearlite unless other processes are being used.

 

[DevinT]

The slower the cooling the coarser the carbides, from fine pearlite to coarse pearlite to fine spheroidite to coarse spheroidite.

Hoss