Billet MR2 – 52100/3CR12 Stainless Clad

HOW TO PREPARE AND HARDEN DARKWING BLADES SAN MAI (3CR12 S/S AND
52100 HIGH CARBON STEEL)

NB* The steel should never be hardened at its full thickness. This will result in the billet
splitting in two. To prepare for hardening the blade should be rough ground to at least
halfway to three-quarters the width (height) of the blade and the core must be exposed on
the edge. To normalize the steel, it should be heated to non-magnetic and allowed to cool to
a black heat (this can be repeated three times for best results). Heat the steel again to non-
magnetic and edge quench. The blade should be submerged in the oil no more than halfway
to three-quarters the height of the blade, allowing the spine to cool down slowly outside the
oil. Once 90 percent of the red colour has disappeared from the spine the knife can be fully
submerged. Once out of the oil and still warm the steel is in an elastic state for a minute or
two and can be straightened by hand and must then be placed directly into the tempering
oven.

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NB* It is imperative that you have your tempering oven ready at temperature before you start
your heat treatment. The blade should not be left lying around in its hardened state for any
amount of time. This will also reduce the chances of any splitting.

ANNEALING PROCESS

The steel, when received, is in an annealed state, and ready for stock removal and drilling. If
you choose to forge the billet, the handle will need to be annealed thereafter to be drilled. To
do this, the steel temperature should be raised to just below critical temperature and then
placed in an insulating medium to cool slowly i.e. perlite, vermiculite, wood ash, agricultural
lime, or a combination of these.

Any further questions please contact De Wet van Zyl – 0796409867