New-York tribune., 1895-09-13

can actually be more rapidly accomplished by
other carbonaceous mixture than that hitherto
employed The process. however even with these
Improvements. Is tedious and expensive. In order,
for example, to Introduce a sufficient amount of
carbon into the face OF thick plate a time con-
sderaby more than proxmate to the thickness
OF the plate must be employed. At the same time.
the carbon sinks TO a certain extent deeply into
the plate. so that the latter may crack much
in the same manner as .he old steel plates which
contained the same amount OF carbon throughout.
Then. again. the immense volume or heat contained
In the thick plates prevented ,ner RAPID cnmng
In the plate surface was not obtained
THE ACKERMAN PROCESS
Lieutenant Ackermans process of treating plates
is simple and at the same time comparatively mex
pensive. They can be treated by it in much less
time than when the Harvey process is used I'm
der Lieutenant Ackermans process. the face of
plate is cut into a number of gashes pockets.
with ridges between. The accompanying
cut which is made from a photograph of the plate
gashes and ridges spaced. and how they out
wardly affect the appearance OF the plate. II is
into both sides. and the top OF the ridges and the
carbon can actually penetrate in all places the de.
sired depth at one and the same time, Instead Of
oozng In from the fiat surface alone In this way. too
the depth OF penetration can be regulated by changing
for thin plates and deeper for thick plates Again.
the percentage OF carbonate depth may be regulated
If IL is desired TO carbonize very quickly to high
percentage the ridges would be thin and BE- more ore
heat becomes concentrated in the ridges, which
| reach high temperature much earlier than the
body of the plate. that the carbonzation begins
earlier In the case of thin plates, these ridges VIII
be forged down even with the surface OF the plate
whole plate has been benefited by being subjected
to kneading and compression. after the loosen;
In the case of thick plates the inventor proposes
to allow the ridges to stand intact, proposition
either Of considerable hardhood, or showing the
possession OF knowledge Of the character or the re.
hitherto seen fit to divulge. Lieutenant Ackerman
nse5 n to the hardened face Of his plates have
material effect on their resistance Cracks formed
rim 10 70 them, nor necessarily follow them. fIe says
that they will stop cracks which go toward them:
rather thick and the exposure to the cementation
is comparatively short carbon penetraes ds O9 ,bS no
ridges leaving the core tough and strong irnc sunse
Gsny IS in felt Thas To sc bottom Gq Of the pockets
eyer there is carbon, an adamantine enVelope vi
is composed of grIdde or lattice work OF hardeded he
waves and depressions OF considerable depth pe'ue'
I'm softer but very much tougher metal.
SUPERIOR TO ORDINARY FACE-HARDENING
This structure. when compared to the ordinary
face-hardenng plate has, 1t ls claimed, all the ad-
vantages of strength and rIgIdity that the airy
bridge work has the solid beam Ordinarily the
depth OF hardened face is about inch, and Is no
greater In an elghteen-nch plate than In sx-lnch
plate but by the OF the gashes employed In the
process OF Lieutenant Ackerman the hardening
| thick plates. and all the benefits OF the treatment
obtained at much less expense, TO IA greater depth
Is stated an experiment has already been made
| with seven-inch plate at Indian Head. whch was
| treated by the Alderman process The plate was
seven inches thick. and was attacked by four armot
piercing proJectiles The cut represents tne p9H, pHs
| OF impact. The first shell struck the plate about
| midway between the top, and bottom. toward the
right side. and the second In the same relative po-
! sitIon on the left side The third shot struck near
the lower left-hand corner ana the fonrth AT me tne
! upper eft-hand corner. All or the prolectles were
more or less damaged In the contact. The striking
velocity OF the first shot was ls6 foot seconds ana
that of the second. third and fourth shots 2lW foot
| seconds The lowest striking energy was 3ool ana
! the highest about 1909 foot tons The tests seem
satisfactorily to demonsrate me pact,aDiby g, h b o
- YnedltIng the cementatlon. point to which Lieu
tenant Ackerman attaches much importance
The plate tried contained gasnes each one tncn III
| depth The length OF time required IN manuacture
for carboniZaton was the same as ,na FrIulie on
an ordinary five and one-haf-inch plate. Inc many
ridges contained from 10 10 - per cent more carbon
a, the sam me depth than the Harvey pates. In fact
the ridges contained more carbon than was desra-
| HE and were too brittle. instead or possessing a
,onrh core for the reason that they had been too
| long I'm the furnace. Lieutenant Ackerinan states
b., a. s preferable In the OF such plates as
,hat @ !, - eated 10 forge down the ridges or II they
| are NOT forged down. make them wider In order
| that they may not become hard through ana h
,hTouqh In the plate tried nearly 20 per cent or the
face was away by the gashes. me depth 1,oo or
/ which was about one-seventh OF the plates thlck
ness Still there was absolutely no crackihg, anu anu
| as stated. the penetration was about SIX nGhss
| III ,he ridges been devised for thicker plate.
ihev would have been wider the pockets less numer-
Gus anG less part Of the thickness The test was
| Conducted 10 determine the correctness OF the N
ventors theory OF the behavior OF ne ridges under
rals,,n of a plate which in every respect repre-
| sented his process. II having been found that the
~, n,orc especially the resistance to penetration.
|