Clinch Valley news. [volume] (Jeffersonville, Va.) 18??-2019, 1898-08-19
MAKING ARMOR.
DESCRIPTION OF THE PLATE PLANT
AT HOMESTEAD.

Single Piate-Tho Tremendous Pressure
Brought to Bear to Shape Them
Owing to the interest manifested
throughout the United States in our
national defences. there has been n
general desire to learn the resources
OF the Carnegie Steel Company in the
matter of supplying armor plate. A
gentleman who has spent several years
in the employ of that company, and
who is thoroughly acquainted with the
processes involved in the manufac-
turc OF armor at Homestead, Penn,
gave complete account of the various
processes OF the work of manufacture.
First of ALL" said he, "the armor
plant at Homestead is made up of the
armor rolling mill, press and machine
shops, and Harveyizing departments.
The rolling mill does not differ MATER
tally from other mills except that the
machinery employed is excessively
heavy. The. press shop, where tho
monster plates are shaped to the lines
, of the vessel for which they arc intend.
cd, offers many features of interest
Here may be found the gigantic press,
pressure to the inch. Then there arc
the huge relocating furnaces and the
oil tank for tempering.
A novel feature about the furnaces Is
the movable beds, or floors This ar
rangement was made necessary be-
cause of the great weight of the plates,
the plan being to draw the bed to the
outside of the furnace, so that crane
may he readily used, as the armor Is
much too cumbersome to be drawn in
the ordinary manner The liquid con-
tanned In the oil tank is Il mixture
of crude petroleum, fish oil and rosin,
fish oil prcdominatng. When plate
Is ready to be tempered it is placed
in one of the furnaces and submitted
to Il severe heat, the size OF the plate
determining the degree of heat and the
length of time required Meanwhile
the oil has cooled to Il temperature of
/ 30 to 100 degrees. 1t being usually
/ much above that owing to frequent
use. The plate is then drawn from the
furnace and submerged in the tank to
depth of six or eight feet, where 1t Is
supposed to remain until the oil has
thoroughly cooled. 1t is then replaced
/ in the furnace and annealed. after
which it is placed in pit and covered
, with cinders. thus allowing the heat
/ to radiate uniformly"
The informant continued: The
armor, assuming it to be Il ten-inch
plate, the thickness of the shield and
coming tower plates of the Oregon
and sister ships. is supposed to re-
main in the cinder pit forty-eight 10
/ sixty hours. 1t is then ready for the
final physical test, which is made to
determine the tensile strength. Should
the plate pass the required test, it Is
then machined and fitted with bolts.
or keys, ready to he fastened to that
part of the vessed for which it is in
tended, the shaping of the plate having
been attended TO before the tempering.
Ii is IN this hardening process that all
armor plate makers experience much
difficulty, the curved plates showing
a decided tendency to warp from their
peculiar shapes when subjected to Sc
we're heat
The Harvey process, about which
so much has been said, is a compli-
Gated method of carbonizing the sur
face of Il plate to tine depth of three
or four inches. Silica sand, slack and
clay mlyture are spread over the
plate, after which it undergoes an in
tense heat, and is finally allowed to
cool off in the furnace. A Harveyized
plate is regarded by armor experts as
much superior to one that is oil tenn
pered, because of its greater density
and consequential resistance"
The time consumed in the manufac-
ture of an ordinary armor plate is
from three to six weeks, but it should
be borne in mind that there are al
ways several in various stages OF COM
pletlon at one time. Once work is be-
gun and the chain set in motion. about
800 tons OF armor can be completed
monthly. This does not seem like n
large amount considering that one
plate sometimes weighs $4,000 pounds.
Before plate is regarded as finished
all the necessary nuts and bolts to
fasten it in place must be completed
and ready to be shipped with it.
When a group of plates is finished.
one of the number is selected by n
member of the Ordnance Bureau to be
forwarded to the Government proving
grounds at Indian Head, there to be
submitted to the final test for ballistic
resistance by the naval experts. Should
the selected plate meet the require.
ments of the test the entire group is
passed. If the selected plate fails to
stand the test, permission is obtained
If possible, to test a second. and. il
needed, third plate. If both the lat
ter plates fail to stand the test the
group they represent is rejected. On
the other hand, if either one passes
the group is accepted by the Govern
ment.