IMPROVEMENTS IN THE MANUFACTURE OF TUBES AND ORDNANCE OF STEEL AND IRON
Year: 1885

page_text: We WILLIAM CHARLES STIFF and HERBERT BACHARN SOMERVILLE BENNETT of
The Credenda Cold drawn Seamless Steel tube Company Ledsam Street Birming-
ham in the County of Warwick Tube Manufacturers do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF TUBES AND
ORDNANCE OF STEEL AND IRON " to be as follows:-
Our invention consists of the improvements hereinafter described in the manu-
facture of tubes and ordnance of steel and iron.
Our improvements have reference principally to the formation of the axial hole
in the cylindrical ingot or bloom or bar from which the steel or irou tube or
ordnance is made.
We will describe our improvements as applied to the manufacture of steel tubes.
In the ordinary method of manufacturing seamless steel tubes a solid cylindrical
ingot or bloom or bar is formed by rolling or hammering or by casting and an
axial hole is made in the said ingot or bloom by drilling or punching the partly
made tube being completed by rolling and drawing in the ordinary way or the said
hole is formed in the casting process. According to our invention we first drill or
punch a small axial hole in the solid ingot or bar and afterwards enlarge the said
hole to the required diameter by a drawing process conducted in the following.
manner.
We fix the axially drilled cylindrical ingot or bar on a bed or holder and while the
said ingot or bar is so fixed we enlarge the small axial hole in it by means of a bulb
mandril worked by a powerful draw bench or machine the rod or stem of the bulb
mandril being passed through the small axial hole in the ingot. By the action of
the bulb of the mandril upon the axial hole through which it is drawn the said
hole is expanded to the required diameter the metal thus displaced expanding
radially and increasing the external diameter of the ingot or bar. The steel ingot
or bar is at the same time consolidated. The ingot or partly made tube after the
hole in it has been increased in diameter to the required extent may by a rolling or
drawing operation be diminished in diameter and the ingot again subjected to the

page_text: action of the bulb mandril so as to again increase the diameter of the hole. Instead
of drawing the bulb mandril through the ingot or bar the bulb mandril may be
stationary and the ingot or bar drawn over the stationary bulb mandril. Or the
mandril may be pushed through the ingot bar.
In this way the ingot or partly made tube may be consolidated to any desired
extent and an axial hole of the required diameter formed in it.
When we make the axial hole by drilling we effect the drilling while the ingot
or bar is cold.
When we make the axial hole by punching we operate on the ingot or bar in a
heated state. All the subsequent processes are performed while the ingot or bar
is hot.
1
The improvements described may be applied to the manufacture of tubes and
ordnance made of steel or iron.
By our invention the manufacture of steel and iron tubes and ordnance is
economized and the tubes and ordnance produced are of a solidity and closeness
of texture unattainable by the ordinary method of manufacture. The production
of waste metal by the drilling or punching process is avoided by the use of our
invention.

page_text: Steel and Iron.
We WILLIAM CHARLES STIFF and HERBERT BACHARN SOMERVILLE BENNETT of
The Credenda Cold-drawn Seamless Steel Tube Company, Ledsam Street, Birming-
am in the County of Warwick, Tube Manufacturers do hereby declare the nature
of the said Invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:―
Our invention consists of the improvements herein after described in the manu-
facture of tubes and ordnance of steel and iron.
Our improvements have reference principally to the formation of the axial hole
in the cylindrical ingot or bloom or bar from which the steel or iron tube or
ordnance is made.
We will describe our improvements as applied to the manufacture of steel tubes.
In the ordinary method of manufacturing seamless steel tubes, a solid cylindrical
ingot or bloom or bar is formed by rolling or hammering or by casting and an axial
hole is made in the said ingot or bloom by drilling or punching, the partly made
tube being completed by rolling and drawing in the ordinary way; or the said
hole is formed in the casting process.
According to our invention we first drill or punch a small axial hole in the solid
ingot or bar and afterwards enlarge the said hole to the required diameter by a
drawing process conducted in the following manner.
We fix the axially drilled cylindrical ingot or bar on a bed or holder and while
the said ingot or bar is so fixed we enlarge the small axial hole in it by means of a
bulb mandril worked by a powerful draw bench or machine, the rod or stem of the
bulb mandril being passed through the small axial hole in the ingot. By the
action of the bulb of the mandril upon the axial hole through which it is drawn
the said hole is expanded to the required diameter the metal thus displaced
expanding radially and increasing the external diameter of the ingot or bar. The
steel ingot or bar is at the same time consolidated. The ingot or partly formed
tube after the hole in it has been increased in diameter to the required extent may
by a rolling or drawing operation be diminished in diameter and the ingot again
subjected to the action of the bulb mandril so as to again increase the diameter of
the hole.
Instead of drawing the bulb mandril through the ingot or bar the bulb mandril
may be stationary and the ingot or bar drawn over the stationary bulb mandril.
Or the mandril may be pushed through the ingot or bar. In this way the ingot
or partly made tube may be consolidated to any desired extent and an axial hole
of the required diameter formed in it.
When we make the axial hole by drilling we effect the drilling while the ingot
or bar is cold.
When we make the axial hole by punching we operate on the ingot or bar in a
All the subsequent processes are performed while the ingot or bar is
heated state.

page_text: bot.
The improvements described may be applied to the manufacture of tubes and
ordnance made of steel or iron.
We will now proceed to describe with reference to the accompanying Drawing
the manner in which our invention is to be performed.
Figure 1 represents in longitudinal vertical section, Figure 2 in plan and
Figures 3 and 4 in cross section a drawbench and appliances connected therewith
which we prefer to use in effecting the enlargement of the small axial hole made
in the solid cylindrical ingot, bloom bar or block, or in the tubular ingot. In
Figures 1 and 2 the drilled or punched ingot or bar or the hollow cast ingot is
represented in position ready for the enlarging operation and in Figure 5 the axial
hole in a taper tube is represented in the act of being enlarged, the said tube
Figure 5 being suitable for the manufacture of ordnance.
The same letters indicate the same parts in the several Figures of the Drawing.
a is the heated axially perforated ingot block or bar supported on the trough
shaped bed or holder b of the drawbench or apparatus the shape of the said bed or
holder being best seen in the section Figure 3. One end of the ingot block or bar a
takes a bearing against the abutment b¹ which is formed with moveable plates fitting
into suitable guides b' and provided with holes of various sizes to suit the sizes of the
bulb headed mandril being used and at the same time to afford the maximum support
to the end of the block a; cis the bulb headed mandril for operating upon the ingot,
block or bar the said mandril being worked by a powerful draw bench or machine.
The rod or stem of the bulb headed mandril o is passed through the small axial
hole a¹ in the ingot, block or bar a and the said rod or stem is fixed to a travelling
shoe or slipper in the ordinary way. The bulb headed mandril c being drawn
through the ingot, block or bar a in the direction indicated by the arrow Figure 1
the bulb of the mandril is made to expand the hole a to the diameter of the said
bulb as illustrated in the partially drawn tube Figure 5. The nietal of the tube
thus displaced by the bulb of the mandril is expanded radially and the external
diameter of the ingot, block or bar thereby increased, the said ingot, block or bar
being at the same time consolidated or condensed and somewhat shortened in length
by the pressure exerted by the mandril in the drawing operation forcing the ingot
block or bar against the abutment b¹.
The ingot, block or bar or partly made tube a after the hole in it has been
increased in diameter to the required extent may by a rolling drawing or com-
pressing operation be diminished in diameter and it may be again subjected to the
action of the bulb headed mandril c in the manner herein before described so as to
again increase the diameter of the hole a¹.
Instead of drawing the bulb headed mandril c through the ingot block or bar
the said bulb headed mandril may be forced through the said block or bar. Or the
bulb headed mandril may be stationary and the ingot, block or bar a drawn or
forced over the same; or both may be moved in directions towards or from each
other.
When the bulb headed mandril is pushed through instead of being drawn
through the hollow ingot a great pressure is put upon the rear part or stem of the
mandril and it is desirable to make the said stem of nearly the same diameter as
the bulb to give it the maximum strength. In order to avoid the risk of pro-
ducing flexure or distortion in the stem of the mandril the hole a¹ must be made
of such a size that the pressure required to expand it to the size of the bulb shall
be insufficient to produce flexure or distortion in the stem of the mandril. When
the ingot or block a is drawn over the bulb headed mandril instead of being
somewhat reduced in length it will be slightly extended.
The ingot, bar, bloom or block may in some cases be placed in the interior of a
strong die or case fitting the exterior of the block or ingot during the action of the
bulb headed mandril thereon, thereby obtaining a compressing action both on the
interior and exterior surfaces of the ingot, block or bar..
By the operations described the ingot, bloom, block or bar or partly made tube a
may be consolidated to any desired extent and an axial hole of the required

page_text: diameter formed in it, or if desired the hole may be for a part of its distance of
one diameter and for another part of a different diameter.
By our invention the manufacture of steel and iron tubes and ordnance is
economized and the tubes and ordnance produced are of a solidity and closeness
of texture unattainable by the ordinary method of manufacture. The production
of waste metal by the drilling or punching process is avoided by the use of our
invention when solid ingots blocks or bars are used.
'
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
The manufacture of seamless steel or iron tubes by operating upon an ingot, bar,
bloom or block of iron or steel having a small axial hole punched drilled or other-
wise formed therethrough by passing a bulb headed mandril through the said axial
hole while the ingot, bar, bloom or block is in a heated state, thereby enlarging the
bore or axial hole and condensing or consolidating the metal, the said operation
being repeated as often as may be required and being combined or not with an
external rolling drawing or compressing operation substantially as herein before
described and illustrated in the accompanying Drawing.