Process of Manufacturing the same.
Year: 1888

page_text: Date of Application, 31st Jan., 1888
Specification Accepted, 16th Mar., 1888
Process of Manufacturing the same.
1, CHARLES A. MARSHALL of Johnstown in the County of Cambria and State of
Pennsylvania, United States of America, Manufacturer do hereby declare the nature
of my invention, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:—
My invention relates to an improvement in the method or process of making
seamless tubes.
The object is to make a tube of iron or steel which shall have a smooth and regular
internal surface, free from splits and cracks and possessing in a high degree the
qualities of lightness, strength and durability.
With these ends in view my invention consists in first casting an ingot of iron or
steel around a core of yielding refractory material, secondly reducing the cast ingot
to a flattened tube blank, and finally opening the blank into a tube.
My invention further consists in certain more particular steps of procedure as will
be hereinafter described and pointed out in the claims.
In the accompanying drawings:
Figure 1 represents an ingot of iron or steel cast around a core of refractory
material. Fig. 2 represents the same reduced to a flattened tube blank. Fig. 3
represents the blank partially opened at one end." Fig. 4 represents a cross section
of the partially completed tube as it appears when ready to be drawn over the
shaping ball or mandrel. Fig. 5 is a cross section taken through the partially
completed tube and oblong point of a mandrel. Fig. 6 represents a cross section of
the finished cylindrical tube, the dotted lines showing the exterior contour of the
original blank. Figs. 7, 8, 9, 10, 11, 12 represent modified forms of ingot cores.
Figs. 13 and 14 represent modified forms of blanks. Figs. 15 and 16 represent
modified forms into which the blank may be partially opened. Figs. 17, 18 and 19
represent different forms of rolls for partially opening the blank, and Fig. 20 represents
a set of guides.
The process will be described with reference to the manufacture of cylindrical
tubes of uniform thickness, although the same steps of procedure would, with slight

page_text: modifications if any, be applicable to the manufacture of tubes of various shapes in
cross section, the only important difference between the manufacture of round and
other shaped tubes being the construction of the shaping rolls and mandrel.
A represents the ingot metal, B the core of refractory material and C the core
casing or ingot lining of previously worked metal which will be referred to as
"superior" metal.
A core B of yielding refractory material, for example powdered or finely divided
graphite having dry fire clay mixed therewith, or, in case the core is required to be
self coherent, damp fire clay mixed sparingly therewith and the mixture baked to
equal moisture, is either alone, or partially or wholly encased by superior metal
supported in a mould and the ingot metal cast around it.
The core is preferably oblong in-cross section, and the ingot when cast is rectan-
gular in cross section with bevelled or rounded corners, and thinner at points
opposite the extremities of the longer transverse axis of the core than at intermediate
points.
The ingot thus constituted, is reduced by external pressure to a flattened blank D,
with finished edges. The edges may either be finished by slight edge pressure alone,
or by trimming, or by heavier edge pressure either alone or in connection with a
subsequent trimming.
The preferred form of blank is that shown in Fig. 2, in which the metal at the
longitudinal edges is somewhat thicker than the wall of the completed tube is required
to be, and the walls of the blank are provided with external bulges or ribs d, extending
longitudinally along the blank at corresponding intervals between the edges. The
excess of metal at the edges is to supply the reduction which would naturally take
place in opening up the blank, and the excess at intervals between the edges is to
furnish the drawing rolls work and bite in drawing the blank over the ball or
mandrel.
The blank is then opened for a short distance at one end, preferably in an oval
form as shown in Fig. 3, care being exercised not to warp the edges. The partially
opened end of the blank is then inserted between a pair of rolls, preferably recessed
substantially as shown in Figs. 17, 18 and 19, the bottoms of the recesses E 'being
provided with grooves e adapted to receive the edges of the blank. The passage of
the blank between said rolls opens it into a form such, for example, as shown in
figures 15 and 16.
These forms, or any form naturally lying between them or such
general form having any desired ratio of vertical to transverse axis in cross section
within very wide limits may be readily formed by varying the spread of rolls, number
of passes, and shape or recess E.
This operation requires no guides for small tube blanks; but wider ones must be
held in their own planes in the middle at a moderate distance from the rolls, or other-
wise both walls of the blank may buckle toward the same side instead of to opposite
sides as desired.
The opening process here described may be aided by passing the opened blank as
it leaves the rolls over a bulb or mandrel, preferably of tapered oval form, which
shall wedge open the blank with more perfect uniformity than is attained by the action
of the rolls alone and need not affect the thickness of walls of tube..
The small grooves e may be used without the shaping grooves E and, if the exact
shape to be given the blank is unimportant without guides, or guides may take the
place of the shaping grooves.
The gist of this step is the progressive opening of the blank by passing it between
rolls which crowd its edges toward each other, one end of the blank having been first
partially opened.
-The-partially-opened-blank may now be inspected-for-defects, particularly for cracks
along the edges, which are liable to occur if the metal is of an inferior or red-short
quality; also, any refractory material, which is preferably made the least in amount
consistent with immunity from welding as already explained which might interfere
with the finishing of the tube, can now be easily removed by a brush, by washing
the interior of the tube or in any convenient way, and it is then ready to be finished

page_text: by one or more passes over a ball or mandrel through a pair of drawing or "pipe"
rollers.
In this operation an ordinary ogival pointed "tube ball," such as used in making
lap welding tube, may be used with guides on the entering side of the rolls to keep
the edges of the blank in the plane of rotation of the rolls. A front view of such
a guide is shown in Fig. 20, the blank being represented in dotted lines. The guides
are represented as bolted to a horizontal "rest," which is secured to the frame of the
rolls. These guides may well consist of rolls having small grooves at the bottoms of
larger grooves as described in connection with the previous step, in operating the
closed blank and they may be driven so as to perform the final, or shaping pass
of the opening process, thus combining in part the two operations of opening and
finishing.
In manufacturing tubes of the boiler tube size, however, the guides are preferably
dispensed with and a bulb is used consisting of a cylindrical rear portion, extending
a short distance only in front of the line joining the axes of the rolls, and a tapered
oval front or point F, see cross section Fig. 5. This bulb or mandrel is fixed upon
the squared end of a rod which abuts against and is held from turning by a support
in front of the roll, at a distance therefrom greater than the length of the tube to be
made, and of such length as to hold the bulb or mandrel in its proper position within
the drawing groove.
The first contact. of the heated partially opened blank and the bulb or mandrel is
represented in Fig. 5. It is plain that the oval form of point thus developes con-
siderable resistance to the twisting of the blank, and causes it to enter with its edges
always in the plane of rotation of the rolls.
With a blank having the proper relative thickness of metal at its edges and sides
a circular tube may be thus formed from the partially opened blank by a single
operation. If a bigher finish is required, the tube may be further drawn either hot
or cold.
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. In the process of making seamless tubes, the following steps, viz. casting an
ingot around a core of refractory material, reducing the ingot with its core therein to
a flattened blank and opening the blank into a tube.
2. In the process of making seamless tubes, the following steps, viz. casting an
ingot around a core of refractory material partially or entirely encased by superior
metal, reducing the ingot to flattened blank and opening the blank into a tube.
3. In the process of making seamless tubes, the following steps, viz. casting an
ingot around a core of refractory material, reducing the cast ingot to a flattened blank
by a flat and edge rolling, opening one end of the blank, and completing the opening
of the blank by edge pressure between rolls.
4. In the process of making seamless tubes the following steps viz. reducing a
hollow ingot containing refractory material to a flattened blank by edge and flat
rolling, opening the blank by first opening one end, subsequently passing the blank
edgewise through pressure rolls, and finishing the tube by drawing the opened blank
over a bulb or mandrel.
5. In the process of making seamless tubes, the following steps, viz. the opening
of the flattened blank by first starting one end open and subsequently passing it
between a pair of edge pressure rolls and then completing the tube by passing it over
a bulb or mandrel.
6. In the process of making seamless tubes, the following steps, viz. forming a
core of refractory material, partially or completely encased in superior metal, casting
an ingot around the core, reducing the ingot thus constituted to a flattened blank,
welding the ingot metal to the superior metal either in casting or reducing or partly
in both, opening the blank by edge pressure and completing the tube by drawing the
opened blank over a flat pointed mandrel.

page_text: 7. In the process of making a tube blank, the following steps, viz. first casting an
ingot around a core, the wall of which consists wholly or partially of superior metal,
and secondly, reducing the ingot to a flattened blank by external pressure.
8. In the process of making a tube blank, the following steps viz. the construction
of a core of yielding refractory material encased wholly or partially within a layer
of superior metal; casting an ingot around said core; and reducing the ingot so
constituted, to a flattened blank by external pressure.
9. In the process of making a tube blank, the following steps viz. casting an ingot
about a core, two diametrically opposite points of which extend nearer the outer faces
of the ingot than the intermediate points, and reducing the ingot so cast and with its
core therein, to a flattened blank by external pressure.
10. In the process of making a tube blank, the following steps, viz. casting an
ingot having an interior lining of superior metal, reducing the ingot to a flattened
form by flat and edge rolling and trimming the edges.
11. A blank for making a seamless tube, consisting essentially of a flattened
metallic band having a partial or complete lining of superior metal, substantially as
set forth.
12. An ingot having a cavity filled with yielding refractory material, the ingot
metal being thinner at two diametrically opposite points of the cavity than at inter-
mediate points, substantially as set forth.
13. An ingot having a cavity lined with superior metal, the ingot metal being
thinner at two diametrically opposite points of the cavity than at intermediate points
substantially as set forth.
14. A finished tube or hollow article whose main outer body is of rolled ingot steel
or iron and its inner surface of more highly worked iron or steel, substantially as
described.
1
P
1000
HERBERT & Co.,
18, Buckingham Street, Strand, W.C.,
Agents to Applicant.