Improvements in or connected with Moulding or Casting and in Moulds therefor.
Year: 1889

page_text: Date of Application, 29th Oct., 1889-Accepted, 30th Nov., 1889
COMPLETE SPECIFICATION.
Improvements in or connected with Moulding or Casting and in
Moulds therefor.
I, FRANCIS DANIEL TAYLOR of the Town of Brockville in the County of Leeds and
Province of Ontario Canada Civil and Mining Engineer, do hereby declare the
nature of this Invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :—
The object of my Invention is to produce castings which shall have upon all their
faces a thickness of decarbonized metal or semi-steel thus giving a perfectly smooth
bright surface requiring no dressing and thereby preserving a soft malleable exterior.
This object is effected according to my invention by lining the moulds with
peroxide of iron usually in the form of hematite or similar iron ore, or metallic oxides,
those being preferred which contain the highest percentage of oxygen. They are used
in a pulverized condition.
In some cases it will be sufficient to cover the inside surface of the mould, i.e. of
the sand in the flask, with the pulverized peroxide of iron or other metallic oxides,
care being taken that there shall be no break in the lining, but I usually prefer and
especially where castings are of large size to form the lining of the mould distinct
from the sand, or backing used, of the flask.
In this case I take the pulverized peroxide, or other metallic oxide, and incorporate
it thoroughly with wood pulp, or equivalent material, in a plastic condition, which
serves as a matrix for the particles.
I then take the pattern, in halves, or otherwise, of any article or piece to be cast,
and cover it to the proper thickness with the above mixture, the amount used being in
proportion to the size and shape of the casting. The pattern with its coating is then
placed in a press, (preferably a hydraulic press) by the pressure of which I obtain
the exact shape or mould required, this is then dried and when dried is ready for
USC.
When required for use I take the shape thus formed and set it on the pattern of the
article to be moulded: I then place over it the part of the moulder's flask to be used,
and fill it in with ordinary moulding sand, or other suitable material used in foundries,
ramming it solid.
The flask is then raised, the pattern being taken out, leaving the shapes composed
of my mixture independent of the moulding sand, which is only used to back them up
and hold them in the flask.
In either of these cases, viz.: whether the peroxide be placed upon the sand, or the
lining be formed separately from the backing, the effect upon the casting, when the
metal is poured in, is as follows.
When the molten metal enters the mould the carbon contained in that portion of
the molten metal which comes in contact with the lining combines with the oxygen
contained in it and is thereby partially or wholly eliminated, thus forming on the
surface of the casting, and according to the proportion of the carbon taken up, a skin
of decarbonized metal which may vary from a mild steel to wrought iron, the
interior of the casting containing the full amount of carbon.
I am aware that peroxide of iron bas be mixed with pig iron to facilitate the
operation of puddling, but it has I believe never been used for foundry purposes.
It must be understood that, although I have found the peroxides of iron to answer
the purposes above described, I do not confine myself specially to their use as other
suitable ores, metals or substances carrying oxygen may be employed.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is -
--
1. As a new article of manufacture a mould for castings lined with peroxide of
iron or equivalent oxygen-carrying substance.
2. A mould lining composed of a mixture of pulverized peroxide of iron or equiva-
lent oxygen carrying substance and wood pulp or equivalent material substantially as
hereinbefore described.
3. The process hereinbefore described of decarbonizing the surface of castings in
moulders' flasks.
1000
J. H. JOHNSON & Co.