Method of and Apparatus for Making Roll-drawn Tubing.
Year: 1899

page_text: Date of Application, 29th Aug., 1899-Accepted, 21st Oct., 1899
Communicated from abroad by HERBERT RUDOLTH KEITHLEY, of 966, St. Nicholas
Avenue, in the City, County and State of New York, U.S.A., Engineer.
Method of and Apparatus for Making Roll-drawn Tubing.
I, SAMUEL SIDNEY BROMHEAD, of 33, Cannon Street, in the City and County
of London, Patent Agent, 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 this invention is to provide an improved method and apparatus
for the economic manufacture of seamless tubing of superior density and
toughness.
To this end, the invention consists of the improvement in the art and the
combination of parts, as hereinafter described and more particularly pointed
out in the claims at the end of this specification.
In the accompanying three sheets of drawings,
Fig. 1 is a diagramatic view partly in section of an apparatus for manufac-
turing seamless tubes according to this invention.
Fig. 2 is a detail view illustrating a portion of the mandrel, a hollow blank
or ingot, and a completed section of the tube.
Figs. 3 and 4 are detail views of the spring jaws for removing the completed
tube from the mandrel.
Fig. 5 is a transverse, sectional view of the apparatus for roll-drawing seam-
less tubing.
!
Fig. 6 is an enlarged view illustrating the gearing which may be employed
for turning the drawing-rolls in axial opposition to the advancing movement of
the mandrel, and
Fig. 7 is an enlarged view illustrating the action of the drawing rolls.
In the manufacture of seamless tubing prior to the present invention, two
operations have heretofore been found absolutely essential.
The first operation or process is what is known as the hot process.
At the present time, the hot process of rolling tubing is carried out by a
variety of machines.
In the first class of machines for performing the hot process, a heated billet
or blank is mounted or secured upon a mandrel, and is reduced in diameter by
ordinary straight-line rolling machines of a similar construction to those
employed for rolling rods.
In other cases power has been applied to force the mandrel and blank
through rolls which are idle or free to turn.
In recent years, the apparatus employed in the hot process of tube rolling
has been modified or improved in a variety of ways, as, for example, by the
substitution of inclined disks for the straight-line rolling mills previously
employed.
These disks have been set at an angle with respect to the path of the mandrel
so as to produce a spiral action, as it were, upon the billet or blank, and various
other changes have been made upon specific sets of apparatus employed, that
is to say, the advances or improvements in the manufacture of seamless tubing

page_text: have in recent years been designed with a view of discarding the old type of
direct, straight-line rolling mills, and have been produced with a view of per-
fecting the more complicated types of the variously modified disk-rolling
machines.
With none of the prior methods of hot-rolling, either practiced with the
ordinary straight-line rolling mills or with the later disk-rolling mills has it
been possible, however, to produce a finished tubing by the hot process alone.
All these prior, hot-rolling processes affect only the outer layers or surface of
the tubing being produced, and the inner layers of the hot-rolled tubes have not
heretofore been compacted to the same degree as the outer layers or surface
thereof, and in order to produce a finished tubing, it has heretofore been abso-
lutely essential to use an additional or second finishing process.
This second finishing process is commonly known as the cold process, and
it ordinarily consists in drawing the unfinished tubing made by a hot process
through a stationary die or dies.
This second finishing or cold process will compact and harden the outer layers
of the tubing, and will produce tubing substantially uniform in diameter, but
even after the application of this second finishing or cold process, the inner
layers of tubing thus produced will be left comparatively soft or of compara-
tively light density.
The present invention has been designed with a special view of producing
finished tubing by a single hot process, thereby eliminating from the manu-
facture of tubing of this class one set of apparatuses, and the entire second
finishing or cold process which is now necessarily employed.
To accomplish this result, this invention has returned to the old form of
straight-line rolling mill, and the desired result is accomplished by using the
rolls of this old apparatus so that, instead of allowing said rolls to act in the
ordinary manner, they are turned in opposition to the advancing movement of
the ingot.
This will cause the rolls to act upon the metal of the blank with a novel,
heavy roll-drawing action, which will produce a stretching, straightening and
compacting of the fibers under pressure; that is to say, the metal will be sup-
ported on the mandrel as upon an anvil, and will be caused to flow thereon, as
it were, so that the entire mass or body of metal will be uniformly compacted
and made homogeneous throughout its thickness, and, by this improvement
in the art, this invention may produce by a single process finished tubing which
it has heretofore been impossible to produce without the addition of the second
finishing or cold process.
!
In the accompanying drawings, 10 designates a mandrel, which may be recip-
rocated and simultaneously revolved, if desired, by any ordinary means, as by
means of a hydraulic press comprising a piston 13 mounted in a cylinder 11, to
which cylinder fluid pressure may be admitted by means of a controlling
valve 14.
↓
To secure the hollow ingot or blank on the mandrel 10, a grooved table 15 is
provided having a pivoted gate or stop 16, which will normally swing down out
of the path of the mandrel 10, and which may be supported in its raised posi-
tion by means of a catch 17.
The idle guide-rollers 18 are arranged to direct the mandrel into a pass of
uniform diameter, between the driven drawing-rolls 19.
A plurality of sets of driven drawing-rolls 19 are preferably employed, and
the axes of the drawing-rolls may be either horizontal, perpendicular, or at
different relative angles with respect to each other, as desired.
The drawing-rolls 19 are turned or driven in direct axial opposition to the
advancing movement of the mandrel, so that their surfaces of contact move
oppositely with respect to the blank.
One form of gearing which may be employed for this purpose is illustrated
in Fig 6.

page_text: As shown therein, a driving shaft 26, journalled in housings 25, may be actu-
ated from an engine or other motor through a crank-arm 27.
Secured on the driving-shaft 26 is a gear 28, which meshes with and drives
intermediate gears 29, which mesh with and turn gears 30 of the drawing-
rolls 19.
A pair of vertical sizing-rolls 20 are journalled near the end of the
housings 25.
A frame 21 having conically recessed spring jaws 22 is employed for removing
the completed tube from the mandrel,
Supporting rollers 24 may be provided in the ordinary manner for receiving
the completed tubes.
In the use of this apparatus, the billet or ingot B having a closed end B¹, is
heated to a high temperature, and placed on the grooved table 15.
The controlling-valve 14 is opened to force the mandrel 10 into the hollow
billet B.
:
The pressure is then momentarily relieved, and the stop 17 raised to allow
the gate 16 to move down out of the path of the mandrel.
Pressure is again turned on, and the idle rolls 18 guide the billet or blank
into the pass of uniform diameter between the drawing-rolls 19.
The drawing-rolls 19 turning or rotating in axial opposition to the operative
stroke of the mandrel 10 will produce the heavy roll-drawing action upon the
billet or blank B before described.
The mandrel 10 may be moved comparatively slowly, and, as the rolls 19 act
under heavy pressure, the metal will have time to flow upon the mandrel to
compact, stretch and straighten the fibers of the inner layers as well as tho
outer layers of the tubes, producing tubes of great toughness, uniform density,
and the metallic fibers of which are parallel with the axes thereof.
The marks of the drawing-rolls 19 upon the tubes will be removed by the
sizing-rolls 20.
When the spring-jaws 22 have engaged behind the end of the completed
tube B, the controlling valve 14 may be turned to admit pressure to the opposite
end of the cylinder 11, to retract the mandrel 10, leaving a complete tube in
position upon the supporting rolls 24.
One especial advantage in the use of this invention in manufacturing steel
tubing resides in the fact that, although the rolls 19 have a drawing action
instead of a rolling action, yet, as they are being constantly turned or rotated,
they will have comparatively large wearing surfaces, and will not have to be
frequently renewed or replaced, which is the case when stationary drawing dies
are employed.
!
Tubing produced according to this invention may be, if desired, finished by
cold-drawing through stationary dies, but, where a further finishing is desired,
the cold blank or tube may again be forced between rollers turning in direct
axial opposition to the advancing movement thereof.
Changes may be made in the practice of this invention by those who are
skilled in the art, without departing from its scope, as expressed in the claims.
For example, a roll-drawing apparatus constructed according to this invention,
may be used in connection with a suitable press and dies for forming a hollow
billet from a solid billet or ingot, so that the entire operation from the solid
billet or ingot to the finished product may be made one continuous process.
The invention, therefore, should not be limited to the details of construction
or operation which have been herein shown and described.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
:―
1. The improvement in the art, and the improved apparatus for manufac-
turing tubes by forcing a mandrel between rolls turning in opposition to the

page_text: advancing movement thereof, substantially as herein desoribed and illustrated
in the accompanying drawings.
:
2. The improvement in the art of producing a seamless tube from a hollow
ingot or blank, which consists in employing a roll-drawing action for disposing
the fibers of the metal under pressure by stretching or straightening them out
in parallel lines by forcing said blank supported on a mandrel between rolls
having registering grooves of uniform depth, and by rotating said rolls in direct
axial opposition to the line of movement of the blank, substantially as described.
3. In a machine for making tubing, the combination of rolls formed with
registering, circumferential grooves of uniform depth to form a pass, a mandrel,
means for forcing the mandrel through the pass, and means for rotating said
rolls so that their surfaces of contact move in direct axial opposition to the
advancing movement of the mandrel, substantially as described.
4. In a machine for making seamless tubes, the combination of a mandrel,
means for reciprocating said mandrel, means for securing a hollow blank or
ingot on the end of said mandrel, rolls formed with registering, circumferential
grooves of uniform depth to form a pass, gearing for turning the rolls in axial
opposition to the operative stroke of the mandrel, and means for removing the
completed tube from the mandrei, substantially as described.
5. In a machine for making seamless tubing, the combination of a mandrel
a hydraulic press for reciprocating said mandrel, a table, a gate for holding a
hollow blank or ingot on said table in position to be engaged by the mandrel, a
plurality of sets of drawing-rolls, each set being formed with registering,
circumferential grooves of uniform depth to form a pass, gearing for turning
said drawing-rolls in opposition to the operative stroke of the mandrel, guide-
rolls for directing the mandrel into the pass between said drawing-rolls, sizing-
rolls journalled at right angles with respect to said drawing-rolls, and spring
jaws for engaging a completed tube to remove said tube from the mandrel during
the return stroke of said mandrel, substantially as described.
Dated this 29th day of August 1899.