The Colfax chronicle. [volume] (Colfax, Grant Parish, La.) 1877-1981, 1882-04-08
The Forging Of Steel.

Steel is one of the most valuable met
quires great care in forging, hardening.
tempering, annealing and general man
agement. Tons of the very best steel
are condemned as bad, when nothing
but the forging has reduced it to that
condition, and all from lack of knowl-
edgei in the management.
In forging cast steel the fire should be
regulated by the size of the work. Q
prefer ahollow fire to be fed with coke.)
To ascertain the heat of the steel, draw
it out of the fire often, for it requires to
be carefully watched to get the proper
heat. II not hot enough, thrust it
quickly in again. The proper degree of
heat is to be Judged by the eye, and care
should be taken not to heat higher than
is absolutely necessary to effect the de-
sired purpose, and to use as few heats as
possible. Too frequent heating and over
heating steel abstracts the carbon, grad
ually reducing it to the state of forged
iron. 1t is the opinion of great many
that, so long as the steel does not fly to
pieces when struck with the hammer, it
is not too hot; but it is an erroneous idea,
as is easily proved when 1t comes to be
hardened, and particularly when it comes
TO be used. ---.-------
An excellent composition for welding
cast steel is prepared BY boiling together
sixteen parts of borax and one of sal
ammoniac over a slow fire for an hour,
When cold, grind it into powder. The
steel must then be made as hot as it will
conveniently bear, and the composition
used the same as sand.
Steel punches, or other small instru-
ments. particularly engraved dies, when,
by accidental exposure to too great heat
they have become spoiled, or, as the
blacksmith says, burned, may be restored
by the following mixture: Two ounces
of bichromate of potassa, one ounce pure
inter, one ounce gum aloes, one ounce
gum arabic and two ounces of resin. The
whole having been well powdered and
mixed, the piece of steel is heated to a
low, red heat, and the powder sprinkled
over it. 1t is then heated again to low,
red heat and cooled. This makes the
piece very hard again. The amount of
inter may be doubled, and that of the
resin taken ten times greater to produce
a higher temper,
In tempering tool for boring cylin-
ders, turning rolls. or any large pieces
of cast iron, let it be as hard as water
viii make it, taking care not to heat it
more than to a cherry red. In the Sec
ond heating, after the tool is hardened,
the first perceptible tint is light straw
color. which makes its appearance when
the heat reaches 40 degrees Fahrenheit.
This gives the metal a maximum of hard
ness, with certain amount of elasticity.
fitting it for lancets, razors and surgical
instruments. At 40 degrees full yell
low is produced, which is the temper
employed for penknives, scalpels and
fine CUTLERY. The temperature of 400
degrees gives brownish-orange, suita-
BILE for shears and chisels used for cutting
iron. At $40 degrees the brownish-yel-
low becomes fecked with purple, the
tint for pocket-knives. Five hundred and
twenty degrees gives blush purple, fit
for table cutlery; while the different
shades of blue from $50 degrees to $40
degrees indicate temper proper for
watchsprings, sword blades, saws and
instruments requiring great elasticity.
Beyond this temperature the metal be-
comes too soft to be used for cutting in
struments.
The temper greatly depends on the
quantity of carbon that is in the steel.
This the practical man soon finds out, and
he tempers or draws down the tool &C
cordingly.
In Switzerland, razors, pocket-knives,
ETC., made from English cast Steel are
tempered by immersing the blades at
dark cherry red into bath composed of
four parts of finely powdered yellow resin.
two parts of fish oil, to which is added.
in a very hot state, one part of melted
tallow, and allowing them to cool per-
fectly; after which they are heated with
out wiping them, and hardened in water
in the ordinary way. The blades harden
ed by this process are found to be more
uniformly tempered than by any other,
making it possible to produce an exceed
ingly fine cutting edge.-Prof Bodwitch,
ig american Machinist.