The sun. [volume] (New York [N.Y.]) 1833-1916, 1891-11-01
HARDENED ARMos PLATES.
TIE Harvey Process Of Tsaghsalag Otes
Described - TreafiAg Q osuA.

TIE Harvey Process sf TsssAsai.g 0tssl
Described - Treating . ss1A.
Tho testing Of srmor plates with surfaces Of
hardened steel created an interest In the proc
sss Of hardening tho surfaoes but. a. patents
were pending. tho details Of the process wore
not explained. In the, specihcstons Of two
patents that have just hsen issued b Hayward
A. Harvey thu methods Of making 4 deors.
mentally hardened srmor plsts and gun. ID
which tho same principles are applied. are Do.
scribed. ,t. ... ,......
The srmor plate Of the desired siss end
shaps. Of . comparatively low, steel. such q
Bessemsr steel or open hearth steel. 10 Laid
natwise on . bed Of finely powdered dry clay OF
sand on the bottom of. c nrebrick cell within
. heated chamber. Of . suitable furnace.
When the plate is imbedded. 90 that its
upper surface Is on the same plane ss the
above the bod. tho treating compartment ID
partly filled with granular csrbonaceous ma
terial which. having been rammed down hard
In the plate. is covered with stratum Of sand
and then q layer Of heavy nrebrickA The
heat In the furnace is then raised to Q high
degree. which is maintained long enough for
the absorption BY the metal Of. say. an add
honal one per cent Of carbon. or enough for
the surface OF the metal to acquire the desired
degree Of hardness. Tho temperature Of the
heating chamber outside Of the treating
chamber is raised to . degree equal to or
Is maintained Tor certain IenstS q am lime 1 ss
which is to be charged with the, excess Of
The more intense the heat H. the better arc
the results. and the longer the treatment 10
the taeRh 70
The penetration 81 the carbon Is greatly facili:
tated By the. continuous firm eomprsssion Of
With heat sufficient to melt cast Iron Q plate
1O1s inches In thickness. containing IS per
TtR s ada
n dr9m 10 per Gent a. depth Of three
ance 81 the treatment for i5O hours after the
heat of the furnace has been raised to the re-
the the Plate tates s FUR
nace. and. without the removal OF the car
sr ehss s@a
be the q
dull cherry-red color the carbonaceoas mate
rial Is removed and the plate is chilled with
The surface Of . plate Of. 1ox inches in
process viii be eIeeedipgly hardened and re-:
when prejsetie six inches ID diameter and
x Il g Ssos sss sssps
Tie prSjeet viii Be Weae a f g the paes ~
stoppags Of the night q the proiectile, and
HETEROGENEOUS crystalline structure Of the
eupercArburized and hardened stratum, It's
tough backing and the entire homogeneltyoi
the plate from 2pe surface to another, except
as % its crystalline structure. there will not be
face. THIS surface of tho plate Is smooth and
clean after the completion, OF the process.
Ip treating a gun ny tho process 1t 10 I'm.
bedded ~ un external layer Of finely powdered
the muEzle is Oiled with finely powdered char
goal. and the reseptacls II placed 10 proper
surface 10 deeper than that Of the Interior. II
is claimed that the external surface acts as an
hoop around the body OF softer
steel and prevents expansion. and that the
soft steel acts as a bnffer to protect the hard
the explosion. The meta! when heated In
close contact with powdered charcoal remains
solid. although exposed to Temperature above
the ordinary melting point