Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1889-05-27
FROM BARS OF IRON.
John Jarrett Describes Exactly How
Tin Plates Are Made
BY BRITAIN's PALM-OM PROCESS
Rolled From Solid Bars Down to an EI-
ceeding Thinness,
THEN PIcKLED AND ROLLED IN OIL


better qualified both by study and expert
ence to write intelligently and entertain
ingly about TN plate and its manufacture
than Mr.. John Jarrett, of this city, the
newly appointed Consul of the United States
to Birmingham, England. For the current
number of the Bulletin, published in Phil
adelphia, under the auspices of the Ameri-
can Iron and Steel Association, Mr.. Jarrett
writes on "How Tin Plates Are Made in
Great Britain" Beside congratulating Mr..
Jarrett editorially upon his new appoint
ment, the Bulletin gives nearly two columns
of its editorial page to his descriptive arti-
Gle, which is reproduced below. 1t will be
considered of double interest in the Pitts
burg region in view of the great promises
made for this locality in behalf of the re-
vived and extended tin industry that is to
spring from the Senate tariff bill, if adopted.
Mr.. Jarrett says:
DEAR SIR: In compliance with your request
for a description of the manner in which tin
plates are made in Great Britain / take
pleasure in sending you the following informa-
uon.
Charcoal iron is no longer used in the manu-
facture of tin plates, and the quantity of puddled
bars now used for this purpose is also very
limited. The bulk of the finer and better
qualities of plates is now made of open-hearth
steel, and nearly all the cheaper grades are
made of low-carbon Bessemer steel. We will,
therefore. deal only with our subject from the
bars of iron or steel (which in tin mills are
generally called "tin bars'') to the finished
plates.
FROM AN IRON BAR.
In the first place we have the bar, delivered
from the bar mill, several feet long, about
seven inches wide. and from one-half to five
eighths of an inch thick, rolled according to
the size of the plates required at so many
pounds per foot The bar is taken and sheared
into the required lengths, say about Is inches,
which would weigh about 10 pounds to the
piece. This would be the length of bar re-
quired to produce sheets IA inches by 20iDches
in size. The bar would eventually be rolled
into 16 sheets of this size, liz of such sheets
forming box. and weighing when timed about
los pounds.
This piece of bar iron, I5 inches long, is placed
in a reverberatory furnace, heated to reduess,
put through the chilled rolls and rolled into
what is termed thick" It is then reheated
and rolled in singles until reduced in thick
ness SO as to be easily doubled after which it is
doubled, reheated, and rolled, three times in
succession. BY this time it will be seen that
the 19pound bar is eight sheets in thickness
In this shape it is rolled until each sheet is re-
duced to the required length and thickness
The whole mass is next taken and sheared into
two parts aud the rough edges taken off We
have then eight sheets in each part adherIng
very closely together. Girls are generally en-
ployed to open or separate these packs" as
they are called, which they do with small
hatchets, protecting their hands with hand
feathers. The plates are now termed "black
plates"
THE PICKLING PROCESS.
The plates are next sent to be picked that is
immersed in heated dilute sulphuric acid. This
process is now generally done by the aid of
patent picking machines, among which are
Hutchings', Morris. Lewis & Hyde's and
others. The plates are placed in a cradle or
receptacle which is lifted by hydraulic power
and dropped down into a tank containing the
acid. The cradle is then given a revolving or
other motion to make the liquid rush between
the sheets. After being subjected to the
action of the acid for some time the cradle is 1
again lifted by the hydraulic power and
dropped into another tank containing an
ample supply of clean water only, the cradle
revolving as in the acid tank, SO that the water
may rush between the sheets and wash away
all trace of the acid. When taken out the
plates are bright and clean. They are then |
placed in closed iron annealing pots and sub |
jected to a bright-red heat in an annealipp |
furnace for from IL to "a hours. Mr. Nc. |
MurtTy. of the Apollo Iron and Steel COMPANY |
has now in operation clever device for picking |
plates which 1 think surpasses any other |
method now in use.
The next process is to pass the plates through |
cold rolls three, -four. or more times, as may be |
deemed necessary. This is called cold rolling |
These rolls are highly polished, and must be
set very accurately in order to give the plates
q perfectly fat set and well polished surface. |
After this rolllng, the plates are again an
nealed, at lower temperature than the first
time, as their surfaces would be damaged by
the slightest degree of sticking or adhering to-
gether. Then they are again picked, as be-
fore, excepting that the liquid Is considerably
weaker, after which they are placed in a
trough, through which q stream of clear water
s continually flowing. They are then taken in
sand and hemp in pads before going to the
'tinman."
THEY GO THROUGH GREASE.
Now comes the last process. The sheets are
ron or steel so far. They next reach the tin
louse, and are placed in trough of clean
vater ready for the tinman, who takes them
lp singly and puts them in a grease pot con-
aiming oil, to soak. After being there O short
ime the tinman places the sheets in large
ron pot containing molten tin, with covering
f palm oil. When the tinman has performed
lis part the plates are handed over to the
whose pot contains more molten
in. After they have soaked little while in
lis pot he raises them with tongs on to the
uOO do uC IS4uiACS bnCIbs Tile surface |
4 each side of the sheet, and, after again dip
ing them into pot containing molten tin,
hey are sent through rolls Whjch work in a
aTge pot containing palm oil. IA boy, called
he ''riser," now lifts the sheets and places
hem Ill bunch, and then HAMS them over to
young woman, who rubs them in bins or
oxes of bran, one after the other, which takes
# the grease. Another youpg woman called
''duster." gives them another rubbing with a
kin duster, after which they are taken to the
ssorting room. Here they are carefully in
pected, and all good plates are classed as
perfects" and defective plates as "wastersn
We have here described what is known as
be s'palm-oil process" The principal feature
( what is called the 'acid-fux process is
hat. in place of palm oil covering the molten
in, an acid fiux is used, being made by mix
IRE of zinc, hydro-chlorate and water. All
ne best plates, however, are still made by the
alm-oil process
Very truly yours JOHN JARRETT.
ecretary of the American Timed Plate Asso. |
citation.
PITTsBURG, MAJ II, 1889. ,
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