Silver steel

On 01-Jan-97, Ralph wrote aboutBEZ.BLKS.:

R> John Burgess,what is silver steel???

Silver steel is a high carbon steel which, unlike ordinary steel
can be hardened by heating to orange then quenching in oil or
water. This makes silver steel so hard that it will scratch
glass, but is useless for tool making at that stage because it is
far too brittle and breaks easily. But having hardened it, you
can clean off the fire-scale with abrasive, carefully reheat the
steel at a point back from the end, and watch colours run from
light straw through dark straw, to plum to blue, and you quench
again when the correct TEMPER is reached for the kind of tool you
want. Wood chisels are quenched at medium straw, whilst punches
are quenched at plum. And so on. Silver steel contains no silver
at all; it is called ‘silver’ because you buy it from engineer’s
suppliers ground and bright-finished to an exact size in rods
from 1/16" to about 2" diameter, and about 36" in length, in the
annealed condition so it can be cut, filed, drilled, and
otherwise worked. Ordinary steel, such as reinforcing rod, nails,
roofing iron, etc cannot be hardened by simple heating and
quenching, and is properly called just iron. It can be
hardened, but that’s another story. And that’s enough, eh?

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   / /    John Burgess, 
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 / //\    johnb@ts.co.nz
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