HARDENING TRICKS
The hardening of steel is accomplished by rearranging the molecules into
a more orderly structure. Within the steel there are complicated forms.
Crystals of ferrite and cementite are mixed throughout but can not actually
blend. The ferrite crystals contain no carbon. The cementite crystals contain
both carbon and iron. A fixed amount of iron and carbon is required to make
a cementite crystal. The amount of carbon in an alloy determines the proportion
of cementite crystals in relation to the ferrite crystals. Kind of like
how many raisens are in your raisen bran. The cementite crystals are more
complicated than the ferrite crystals. So like the straw in the brick or
the fiber in the fiberglass the cementite crystals provide a matrix for
the ferrite to allign with. The union of a cementite crystal with one or
more ferrite crystals is called a martinsite crystal. The more random the
mix the softer the steel. The more the martinsite allignes the cementint
and ferrite the harder the steel. The cementite crystal can hold a certain
number of ferrite crystals. Once full it becomes isolated. Say a perfect
mixture is made and a perfect union made between each and every cementite
crystal and every martinsite crystal has a cementite crystal bonded with
its capacity of ferrite. Then the steel molecule is so integrated that it
becomes no longer able to hold on to its neighbors. The steel becomes what
they call carborundum. Like hard sand. Fused with heat so that its own slag
holds it together this material is used to make grind wheels and whet stones.
Used to sharpen knives not make them. The cementite crystal is like a bundle
of barbs. The barbs flex under heat grabbing hold of ferrite crystals. Or
force can be used to push ferrite crystals into the barbs of the cementite
crystals. In industrial practice heat is rarely used on thin materials.
In the early seventies I worked with a four slide machine making springs.
No heat was ever, ever used. The carbon steel wire was fed between alternating
rollers to harden it. Just like bending a wire back and forth till it gets
so brittle it breaks. This is how all wire springs are made. Heat is impossible
to manage exactly enough to make detailed coil springs. However force can
accomplish any thing heat can and more when hardening steel less than one
eighth inch thick in any dimension. Heat can only harden uniformly whereas
force can harden specific fields and surfaces. An armour plate can be hardened
by the use of force in specific degrees and areas. Such as the spots where
the holes and slots are. These can be left softer so cracks are not a problem.
The key to hardening by force is time and repeated applications of hardening
actions. If a piece has suitable depth like elbows, knees, and helmets the
force can all be applied during the forging of the contour. Taking time
to planish between deepening passes. The flatter pieces however need some
help. So for the maximum hardness you take the cut sheet and planish it
inside out. Hard and firm except where the edges are to be rolled and where
holes will be. This will give the plate some depth. Then turn the plate
over and flatten it carefully and with uniform bites. Next planish it right
side out. This sets up crystals with the first pass. Then more when it is
flattened and more when it is re-planished. Resulting in three times as
many martinsite combinations as the stock metal. A high carbon steel will
heat treat easier but using force to harden it will usually harden it too
hard. Cracking and breaking. An alloy is required. Simple 9% tool steel
turns brittle far too easily so we use 41-20 cutlery steel for spectacularly
hard examples. However mild steel has plenty of carbon to harden using force
where it does not have enough to harden by fire. The martinsite crystals
tend to seek each other and isolate from combined ferrite crystals. So what
martinsite exists forms strands. Pounding tends to isolate martinsite strands
and heating tends to disperce them. The heat treatment method increases
the number of martinsite crystals but cannot structure them. Careful application
of force and counter force can easily produce complicated strand structures
within the steel that strengthen far more efficiently. Like a honey comb
of hard material immersed within the softer whole. Dynamic forces are used
in modern architecture. The use of balanced counter forces began with the
Eiffel Tower and sky scrapers are now common. Without knowing it the old
armoursmiths used these dynamic counterforces to harden steel in the white
smiths method. The same way silver was hardened by the silver smiths that
took over the armour making industry from the black smiths in the fourteenth
century. Think of each strike to the steel as a splash. Each time you hit
the steel, you create inside of it, a circle of effect that creates a circle
of hardened martinsite strands. The next overlapping strike creates another
such ring and so on. These rings of strands combine into a dynamic structure
that is impressive in its ability but only appears if carefully laid down.
Invisible structures within a thin plate. These must be very organized to
have effect. Like weaving chainmail within the plate. Lighting is extremely
important! Always use a three point lighting system so that each impact
point can be exactly seen. The slight darkening of the metal can clearly
be seen so that the pattern of planishing strokes can be laid down exactly.
That darkening represents the same effect on the steel that hardening and
drawing has. So the steel darkens as it hardens. A finely planished piece
will present somewhat darkly even when polished. In conclusion it can be
said that the use of systematic impacts and bending the metal back and forth
in patterns of movement can harden mild steel, carbon steel, and alloy steel
less than one eighth inch thick at least as effectively as heat for the
purposes of making armour, and in practice has proved to be able to make
steel with less carbon as strong and impact resistant as more expensive,
higher carbon alloys.
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