Note: Descriptions are shown in the official language in which they were submitted.
~L23~ 8
METHOD OF MANUFACTURING A CYLINDRICAL BILLET
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a method of manufacture
in a cylindrical billet and more particularly to a method
of manufacturing a cylindrical billet having a predetermined
length usable as starting material for producing a pipe.
DESCRIPTION OF THE PRIOR ART
. .
To practice the conventional method of manufacturing a
seamless steel pipe Mannesmann type plug mill, Mannesmann
: type asset mill or the like have been heretofore employed.
In the conventional manufacturing facilities as mentioned
above seamless steel pipes are typically produced by way of
the steps of heating a solid billet having a round or square
. cross-sectional configuration, piercing it to form a cylinder
; eel billet which is usable as starting material for making
a required steel pipe and causing it to be subjected to die-
meter enlarging or thickness reduction rolling.
In order to assure that seamless steel pipes having a
high quality are manufactured a a reduced cost a variety of
technical research and development works have been conducted
long since with respect to each of the above-mentioned
-- 1 --
~LZ3C1 21~3
manufacturing steps. In practice, however, any remarkable
improvement fails to be achieved in respect of saving of
material and thermal energy, increased efficiency of opera-
lion and reduction of manufacturing cost.
,
SUMMERY OF THIS INVENTION
Hence, the present invention has been made with the
foregoing background in mind and its object resides in pro-
voiding a method of manufacturing a cylindrical billet which
does not require the conventional steps of blooming heating
piercing and diameter enlarging each of which constitutes
an essential part for the eo~ventional manufacturing method.
Other object of the present invention is to provide a
method of manufacturing a cylindrical-billet which makes it
possible to produce a large number of seamless steel pipes
without any intermittence while-few amount of thermal energy
- is consumed therefore
Another object of the present invention is to provide a
method of manufacturing a cylindrical billet which assures
remarkable saving of material and thermal engery and product
lion at a high operational efficiency.
To accomplish the above objects there is proposed accord-
in to the present invention a method of- manufacturing a
cylindrical billet essentially comprising the steps of
drawing a east slab from a casting mold on a continuous
- 25 casting stand, spirally winding or bending it around
~.Z3~2~8
rotating mandrel with the aid of a plurality of guide rollers,
jointing together both the end faces of the wound or bent cast
slab to a cylindrical body and cutting it to a predetermined
length when it is displaced away from the free end of the
mandrel by a certain distance.
Further, there is proposed according to a preferred em-
bodiment of the present invention a method of manufacturing
a cylindrical billet further including the steps of spirally
winding the cast slab around the rotating mandrel while
thrusting it toward the latter by means of the guide rollers,
axially thrusting the one side face of the cast slab by, . . ..--
means of a pusher including a guide face which is inclined at
a certain angle relative to the axis of the mandrel in order
.. to assure that the adjacent end faces of the cast slab come
in contact with one another and jointing together the ad-
jacent end faces of the spirally wound cast slab. .
Further, there is proposed according to other preferred
embodiment of the present invention a method of manufacturing
a cylindrical billet further including the steps of rolling ,
the cast slab to enlarge it in width in the lateral direction,
kenning both the side parts of the flattened cast slab
around the mandrel with the aid of two arrays of guide not-
tens so as to encase the mandrel with the cast slab in such
a manner that a contact line between both the end faces of
US the cast slab extends in the direction of movement of
the latter and jointing together both the end faces of the
"
~23C:~Z~
cylindrically bent cast slab in the form of a seam pipe.
Further, there is proposed according to another embody-
mint of the present invention a mother of manufacturing a
cylindrical billet essentially comprising the steps of draw-
lung a plurality of cast slabs from a plurality of casting molds on a continuous casting stand, each of said cast slabs
having a cross-sectional configuration which corresponds to a
fragment of the annular cross-sectional configuration of a no-
squired cylindrical billet divided by the number of cast slabs,
bending each of the cast slabs around a rotating,mandrel:'.by
means of a plurality of guide rollers until both the end
faces of the one cast slab come in contact with those of the
other cast slab in such a manner that a contact line between
both the end faces of the adjacent cast slabs extends in the
direction of movement of the cast slabs, linearly jointing
together the end faces of the adjacent bent cast slabs in a
face-to-face relation and cutting the thus formed cylindrical
body to a predetermined length when it is displaced away from
the free end of 'the mandrel by a certain distance.
Further, there is proposed according to further another
embodiment of the present invention a method of manufacturing
a cylindrical billet essentially comprising the steps of
drawing a cast slab from a casting mold on a continuous cast-
in stand, roll forming it to the semi-circular cross-
sectional configuration while it has very few resistance
lZ3~)Z~L~
against deformation, cutting the roll formed cast slab to
a predetermined length, press working the superimposed assume-
blue of two roll formed east slabs which are laid in a press
work device with a mandrel interposed there between along the
axis of a cylindrical eonfiyuration of the assembly, placing
one semi-eylindrical cast slab on the other semi-eylindrical
east slab in the form of a cylindrical body and jointing to-
getter the thus superimposed assembly of two semi-eylindrieal
east slabs.
Further, there is proposed aecordiny to still another em-
bodiment of the present invention a method of manufacturing
a cylindrical billet essentially comprising the steps of
drawing two east slabs from two cast molds on a continuous
casting stand, each of said east slabs having a rectangular
eross-seetional configuration, guiding the cast slabs for-
ward with the aid of a plurality of forming rollers and a
plurality of grooving rollers in such a manner as to cause
them to be united together by means of a pair of uniting
rollers, said forming rollers serving to gradually roll
form the outside surface of each of the east-slabs to the
semi-eurcular configuration while said yrooviny rollers
serving to gradually form on the inside surface of each of
the east slabs a longitudinally extending recess having the
semicircular eross-sectional configuration, jointing to-
getter the thus cylindrically united cast slabs to a
... .
'~Z31)Z~
1 cylindrical body in a face-to-face relation and cutting
the -thus formed cylindrical body to a predetermined
length when it is displaced away from -the pair of unit-
in rollers by a certain distance.
Further there is proposed according to another
embodiment of the present invention a method of manufac-
luring a cylindrical billet utilizing a mandrel and a
plurality of guide rollers, which comprises:
drawing a cast slab from a casting mold on a
continuous casting stand while simultaneously deforming
the cast slab around the periphery ox the mandrel with
the aid of the plurality of guide rollers;
joining together both end faces of the cast
slab;
pressing the cast slab against the mandrel so
as to reduce the thickness of the cast slab so as to
form a cylindrical body of substantially uniform thick-
news and diameter; and
cutting the thus formed cylindrical body to a
predetermined length upon displacement thereof away
from the mandrel a certain distance.
Other objects, features and advantages of the
present invention will become apparent from reading of
the following description made in conjunction with
several preferred embodiments thereof with reference to
the accompanying drawings.
: ''' '
~23~)2~3
BRIEF DESCRIPTION OF THE DRAWING
_
The accompanying drawings will be briefly described be-
low.
Fig, l is a schematic perspective view of manufacturing
facilities for practicing a method of manufacturing a Solon-
Dracula billet in accordance with the first embodiment of the
invention
Fig. 2 is a cross-sectional view of a cast slab drawn
from the manufacturing facilities in Fig, l, said cast slab
having inclined end faces,
Fig, 3 is a cross-sectional view illustrating how the
adjacent inclined end faces of the cast slab in Fig. 2 are
welded together with a V-shaped welding groove formed there-
between.
Fig, 4 is a cross-sectional view of a cast slab drawn
from the manufacturing facilities in Fig, 1, said cast slab
having other type of inclined end faces,
Fig. 5 is a cross-sectional view illustrating how the
adjacent inclined end faces of the cast slab in Fig, 4 are
welded together with other type of V-shaped welding groove
formed there between.
; Fig 6 is a schematic perspective view of manufacturing
facilities for practicing a method of manufacturing a
cylindrical billet in accordance with the second embodiment
, .
Jo - 7
1~3~)2~L8
of the invention.
Fig. 7 is a schematic perspective view of the rear port
lion of the manufacturing facilities in Fig. 6.
Fig. 8 is a cross-sectional view of a cast slab drawn
from the manufacturing facilities in Fits. 6 and 7, said
cast slab having inclined end faces.
Fig. 9 is a corss-sectional view of a cast slab drawn
from the manufacturing facilities in Figs. 6 and Swede
cast slab having other type of inclined end faces.
Fig. 10 is a cross-sectional view illustrating how the
adjacent inclined end faces of the cast slab in Fig. 8 are
welded together with a V-shaped welding groove formed there-
between.
Fig. 11 is a cross-sectional view illustrating how the
adjacent inclined end faces of the cast slab in Fig. 9 are
welded together with other type of V-shaped welding groove
formed there between.
Fig. 12 is a schematic partially sectioned plan view of
manufacturing facilities for practicing a method of manufac-
luring a cylindrical billet in accordance with the third embodiment of the invention.
Fig. 13 is a cross-sectional view of the manufacturing
facilities taken in line II - II in Fig. 12.
Fig. 14 is a fragmental cross-sectional view of a cast
slab drawn from the manufacturing facilities in Fig. 12,
_ _
~2302~L8
said cast slab having inclined end faces.
Fig. 15 is a fragmental cross-sectional view of a cast
slab drawn from the manufacturing facilities in Fig. 12,
said cast slab having other type of inclined end faces.
Fig, 16 is a cross-sectional view illustrating how the
adjacent inclined end faces of the cast slab in Fig. 14
are welded together with a V-shaped welding groove-formed
thereb-tweeni.
Fig. 17 is a cross-sectional view illustrating how the
adjacent inclined end faces of the cast slab infix 15 are
welded together with other type of V-shaped welding groove I-
formed there between.
Fig. 18 is a cross-sectional view of a cylindrical billet
produced by the manufacturing facilities, taken in line
-15 VII - VII in Fig. 12.
Fig. 19 is a schematic perspective view of manufacturing
facilities for practicing a method of manufacturing a
cylindrical billet in accordance with the fourth embodiment
of the invention: ;
Fig. 20 is-a schematic perspective view of manufacturing
facilities for practicing a method of manufacturing a Solon-
Dracula billet in accordance with the fifth embodiment of
the invention, and
Fig. 21 is a cross-sectional view of a cast slab which
is roll formed with the aid of a concave drum shaped forming
roll and a grooving roll.
_ g _
~2302~8
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now, the present invention will be described in a great-
or details hereunder with reference to the accompanying
drawings which schematically illustrate preferred embody-
mints of the invention.
First, description will be made below as to a method of manufacturing a cylindrical billet in accordance with the
first embodiment of the invention with reference to Figs. 1
to 5.
In fig. 1 reference numeral 1 designates a tundish, no-
furriness numeral 2 does an immersion type nozzle, reference
numeral 3 does a casting mold, reference numeral 4 does a
cast slab extending downward from said casting mold 3, no-
furriness numeral 5 does plural pairs of guide rollers servo
in to guide said downwardly moving slab 4, reference numeral 6 does a mandrel extending in a substantially
horizontal direction at a right angle relative to the
downwardly moving slab 4, said mandrel 6 being inclinable
and rotatable, reference numeral 7 does a pusher arranged
around the mandrel 6, said pusher 7 being provided with an
annular guide face 8 which is inclined relative to the
axis of the mandrel 6, reference numeral 9 does a plurality
o-E guide rollers for spirally winding the cast slab 4
around the mandrel 6 by forcible thrusting it against the
cylindrical surface of the mandrel 6 while it moves
-- 10 --
~302~8
downward with its let hand edge face pa being guided by
means of the guide face 8 of the pusher 7, reference numb-
fats if and 12 do an electro-slag welding device for weld-
in the spirally extending end face pa of the cast slab 4
to the adjacent one and reference numeral 13 does a plural-
try of concave drum shaped sizing rollers for reducing the
thickness of the spirally welded cast slab, that is, Solon-
Dracula billet by thrusting it against the cylindrical surface
of the mandrel 6.
The cross-sectional configuration of the outset portion
of the casting mold 3 is not shown in the accompanying draw ;--
in but it is generally configured in such a manner that
: the vast slab 4 has inclined end faces 21 or 22 as Lucite-
; rated in Figs. 4 and 5. Alternatively the inclined end
- 15 faces 21 or 22 may be formed by means of the plural pairs of
guide rollers 5.
Next, description will be made below as to how the method
in accordance with the first embodiment Ox the present
invention is practiced Wyeth the aid of the manufacturing
facilities as constructed in the.above-described manner.
First, an inclination angle of the mandrel 6 is adjusted
so that stress produced during spiral winding of the cast
slab 4 and spiral pitch of the latter are properly control-
led. Next, the mandrel 6 is caused to rotate in the direct
lion as identified with an arrow mark in the drawing.
-- 11 --
~23~:)2~L8
after leaving the casting mold 3, the cast slab 4 with the inclined end faces extending along both the sides there-
of is guided downward by means of the plural pairs of guide
rollers 5. Further, it is spirally wound around the mend-
net 6 by one turn while one of the end faces of the cast slab 4 is trusted in the axial direction of the mandrel 6
by means of the guide face 8 of the pusher 7 in such a
manner as to cause it to be inclined at a certain incline-
lion angle relative to the axis of the mandrel 6, said in-
clinician angle being determined in accordance with the required spiral pitch, and moreover it is trusted against
the cylindrical surface of the mandrel 6 with the aid of
! the guide rollers 9. Alternatively, the guide rollers 9
may be arranged so as to wind the cast slab 4 around the
mandrel 6 merely by half turn because of the fact that it
moves forward in the axial direction while it is being
wound along the mandrel 6 due to its plastic deformation
caused by the dead weight thereof. It should be noted
that the guide rollers 9 are designed so as to be forcibly
rotated for the purposes of guiding, feeding and forming
operations.
On completion of winding of the cast slab 4 around the
mandrel 6 by one revolution electro-slag welding is car-
fled out at the upper end area of the thus formed Solon-
Dracula body in order to weld both the inclined end faces
.
. - 12 -
~X30Z~8
pa together, for instance, as illustrated in Figs. 3 and
5. During the electro-slag welding operation welding
material or molten metal to be added to the junction port
lion is supplied from the same material supply source as
S that for the east slab 4 and therefore the completed Solon-
Dracula billet has uniform chemical composition throughout
the whole length.
As the downwardly moving cast slab 4 is spirally wound
around the mandrel 6 with the aid of the plural pairs of
smaller guide rollers 5 and the larger guide rollers 9
while it is trusted in the axial direction by means of the
pusher 7 so as to cause both the end laces pa of the east
. slab 4 to abut against one another to be welded together,
the thus cylindrically wound east slab, that is, eylindri-
eel billet 26 moves forward in the direction as identified
with an arrow mark Z in Fig 1 while it is rotated in the
- direction as identified with an arrow Marx Z.
During the forward movement of the cylindrical billet
I: 26 the latter is subjected to thickness reducing by means
20 of a plurality of sizing rollers 13 adapted to rotate in
the direction as identified with an arrow mark S, said size-.
in rollers 13 being trusted toward the cylindrical surface
of the mandrel 6 with the aid of a thrusting mechanism
(not shown), whereby the inner structure of the cylindrical
billet 26 becomes metallurgical uniform.
- 13 -
lZ3~)Z~
Since an arrangement is made in the above-described
manner such that the mandrel 6 is caused to rotate in the
rotational direction X opposite to the rotational direction
Y of the cylindrical billet 26, it is assured that rotation
of the mandrel 6 is entirely free from forward movement of
the cylindrical billet 26 without any fear of causing an
occurrence of hot sticking there between. However, it has
been found that drawing of the cast billet 4 from the cast-
in mold 3 is easily effected when the mandrel 6 is caused
to rotate in the same direction as the rotational direction
Y of the cylindrical billet 26.
When the thus manufactured cylindrical billet 26 is disk
placed away from the free end of the mandrel 6 by a pro-
- determined distance, it is cut off to a predetermined length
by operating a cutting device which is not shown in the
drawing.
Since the cylindrical billet still has a considerably
high temperature even after completion of cutting operation,
it may be further subjected to rolling work until a final
product of steel tube is obtained. As will be readily
understood from the above description, any heating process
as is required for practicing the conventional method will
not be necessary or can be reduced to the minimized ox-
tent, resulting in saving of thermal energy being assured.
Alternatively, the thus manufactured cylindrical billet may
I,
- 14 -
~L230~8
be used as raw material for manufacturing a steel tube in
accordance with the conventional method.
The cylindrical billet manufactured by way of the steps
as described above has inner and outer surfaces which are
very smooth and have good appearance owing to the fact that
the cast slab formed in accordance with the continuous cast-
in process has front and rear surfaces which are very
-smooth and have good appearance and therefore any additional
surface processing will not be required therefore or it can
be minimized.
Further, the inner diameter of the cylindrical billet can -~~
be easily changed as required by changing the outer diameter
of a mandrel and the outer diameter of the same can be cast-
lye changed by changing the thickness of a cast slab. Accord-
tingly, a cylindrical billet having various inner and outer diameters can be manufactured without any particular Defoe-
gully.
Since a cylindrical billet is formed by spirally winding
a cast slab in the above-described manner, any cylindrical
billet having a large inner diameter can be manufactured by
using a regular size of cast slab.
In the above-described embodiment of the invention an
electro-slag welding process is employed for jointing to-
gather the adjacent end faces of a cast slab but the in-
mention should not be limited only to this. It may be
SLY
replaced with another process such as electro~gas weldiny,rolling, forging or the like.
It should be of course understood that the method of
the invention of manufacturing a cylindrical billet should
S not be limited only to steel pipe but it may be applied to
metallic material other than steel, for instance, titanium.
As will be apparent from the above description, the
method of manufacturing a cylindrical billet is practiced
according to this embodiment of the invention by way of the
steps of preparing a cast slab in accordance with the con-
ventional continuous casting process, spirally winding it
around a rotating mandrel and joining together the adjacent
end faces thereof which are brought in abutment against one
another under the influence of thrusting force with the aid
of a plurality of guide rollers and a pusher so that a no-
squired cylindrical billet is formed. Thus, the method in
accordance with this embodiment of the invention does not
require the steps of blooming, billet heating and piercing
each of which constitutes an essential step for practicing
the convention method, resulting in no occurrence of no-
diction in yielding rate attributable to the steps of bloom-
in and piercing, remarkably increased operational effuse-
envy and substantial reduction in expenditure required for
installing the manufacturing facilities being assured.
Accordingly, cylindrical billets are manufactured at an
- 16 -
~23~18
inexpensive cost.
Further, since the method according Jo this embodiment
of the invention is practiced by using a cast slab which
has constant thickness, uniform inner structure and smooth
front and rear surfaces, said cast slab being prepared in
accordance with the conventional casting process, the thus
manufactured cylindrical billet has inner and outer surfaces
which are very smooth and have good appearance with reduced
rate of occurrence of irregular thickness and highly in-
creased concentricity and dimensional accuracy being assure
Ed Owing to this it is possible to eliminate a part of
secondary processing steps, for instance, a step for en-
tanging pipe diameter and therefore subsequent pipe process
sing steps are easy to be carried out for the cylindrical
billet.
Further, since the method according to this embodiment
of the invention makes it possible to easily manufacture a
; cylindrical billet having any combination of thickness and
diameter ranging from a combination of thinner thickness
and small diameter to a combination of heavier thickness
and larger diameter merely by changing the outer diameter
of a mandrel and the thickness of a cast slab, it is pro-
fireball applicable either to a case where small number and
many kinds of cylindrical billets are manufactured or to a
case where large number and few kinds of cylindrical billets
sly
are manufactured.
Further, since the method according to this embodiment
of the invention is practiced by using a cast slab prepared
in accordance with the conventional continuous casting pro-
cuss to manufacture cylindrical billets, manufacturing discontinuously carried out throughout the whole steps from tune
beginning step of steel making to the final step of joint-
in together the adjacent end faces of the spirally wound
slab. Moreover, when subsequent pipe processing steps are
required, they are carried out without any intermittence
while reduced amount of thermal energy is consumed for
reheating cylindrical billets.
Next, description will be made below as to a method of
manufacturing a cylindrical billet in accordance with the
second embodiment of the invention with reference to Figs.
6 to 11.
Particularly, Fig. 6 schematically illustrates a con-
ventional horizontal type continuous casting stand by way
of a partially broken perspective view. In
Fig. 6 reference numeral 31 designates a casting mold, no-
furriness numeral 32 does an outlet portion of said casting
mold 31, reference numeral 33 does a cast slab horizontally
moving away from said outlet portion 32, reference numeral
34 does plural pairs of guide rollers arranged in parallel
to one another at a right ankle relative to the axis of
,
... .
- 18 -
30Z~8
movement of the cast slab 33, one group of said guide rollers
34 briny located above the cast slab 33 and another group of
the same being located below the latter, reference numeral 35
does a plurality of holding rollers located below the cast
slab 33 which has passed through the groups of guide rollers
14, reference numeral 36 does a cove drum shaped sizing
roller located above the cast slab 33 which has passed above
the holding rollers 35, reference numeral 37 does a notate-
bye mandrel extending in the direction of movement of the
cast slab 33 which has passed below the sizing roller 36,
reference numeral 38 does a group of guide rollers arranged .
in a spaced relation along both the side parts aye of the
cast slab 33 to thrust the latter toward the mandrel 37 in
such a manner as to encase the manured 37 with the cast
slab 33 until both the end faces 33b of the side parts aye
are brought in abutment against one another, reference numb-
: fat 41 does an electro~slag welding apparatus for welding
together both the end faces 33b and reference numeral 42 doe
a plurality of conveyance rollers In Fig. 7 reference
: 20 numeral 45 designates plural groups of concave drum shaped
: sizing rollers arranged around the cylindrically formed
cast slab 46, that is, cylindrical billet 46 which has
passed by the electro-slag welding apparatus 41 after come
pletion of wending operation, each of said groups comprising
your sizing rollers which are located along the periphery of
,
-- 19 --
~lX3~ 8
the mandrel 37 with an angular distance of 90 degrees kept
between the adjacent ones, and reference numeral 47 does
a plurality of conveyance rollers for conveying a cylinder-
Cal billet 46 after it has been cut to a predetermined
length.
The cross-sectional configuration of the outlet portion
32 of the casting mold 31 is not shown in the accompanying
drawing but it is generally configured in such a manner
that the cast slab 33 has inclined end faces 33b as illicit-
rated in Figs. 8 and 9 to form a V-shaped welding groove 51
or 52 between the adjacent ones. Alternatively, the V- -
shaped welding groove 51 or 52 may be formed by means of
the plural pair of guide rollers 34.
Next, description will be made below as to how the
method in accordance with the second embodiment of the in-
mention is practiced with the aid of the manufacturing
facilities as constructed in the above-described manner.
First the cast slab 33 is drawn from the outlet portion
32 of the casting mold 31` in the horizontal direction while
it is guided by means of the plural pair of guide rollers
34. After it has passed through the guide rollers 34, it
is caused to expand to the illustrated increased width us-
don the influence owe rolling operation carried out by
means of a depressing roller (not shown) in cooperation with
the holding rollers 35.
- 20 -
~L230Z~L8
Both the side parts aye of the rolled cast slab 33 are
then trusted toward the convex drum shaped sizing roller
36 by means of the guide rollers I and further they are
gradually brought in contact with the periphery of the man-
duel 37 with the aid of the guide rollers 38 as if the man-
drip 37 is encased with the cast slab 33 until the latter
is wound about the mandrel 37. As a result the adjacent end
faces 33b of the side parts aye come in contact with one
another with a V-shaped welding groove formed there between.
As a next step both the end faces 33b of thy side parts
aye are welded together with the V-shaped welding grooves 51 --I
filled with molten metal as illustrated in Figs. lo and if
with the aid of the electro-slag welding apparatus 51 where-
by a required cylindrical billet 46 is formed. As is appear-
lo en from Fig. 6, the welded seam 55 extends linearly as the
cast slab 55 moves forward. In other words the cylindrical
billet 46 is obtained in the form of a seam welded pipe. It
should be noted that welding material or molten metal to be
added into the Shaped welding groove during welding opera-
lion is supplied from the same material supp~y~source aesthete of the cast slab 33 and thereby the cylindrical billet
46 has an uniform inner structure through the whole length
thereof.
The thus manufactured cylindrical billet 46 is con-
vexed in the ruptured direction as seen in the drawing by
~302~L8
means of the conveyance rollers I so that it is subjected
to thickness reduction under the influence of rolling force
imparted by the group of concave drum shaped sizing rollers
45 each of which is rotating while it is moving forward,
said rolling force being exerted on the cylindrical surface
of the cylindrical billet 46 in the four radial directions.
After completion of reducing operation the inner structure
of the cylindrical billet 46 becomes uniform metallurgical-
lye .
Since the mandrel 37 is caused to rotate during the
above-mentioned forming steps, there is no fear of causing - -
the mandrel 37 to be stuck to the cylindrical billet 46.
Finally, the cylindrical mandrel 46 is cut to a pro-
determined length at -the throat portion aye of the mandrel
37 by operating a cutting device which is not shown in the
drawing. As a result a required cylindrical billet having
the predetermined length is obtained.
s is apparent from the above description, this embody-
mint is different from the foregoing one merely in respect
; 20 of the fact that a cast slab is drawn in the-horizontal
direction in accordance with the conventional horizontal
type continuous casting process but both the embodiments
are identical to one another in respect of the fact that the
cast slab is wound around the mandrel with both the side
parts being brought in abutment against one another as if
- 22 -
~30Z18
the mandrel is wrapped with the cast slab and they are
then jointed together by welding operation so that a Solon-
Dracula billet is produced in the form of a seam pipe. Thus,
the same inventive effects as those in the foregoing em-
bodiment are obtainable. Accordingly, the method in accord-
ante with this embodiment does not require the steps of
blooming, billet heating and piercing each of which keenest-
lutes an essential step for practicing the conventional
method, resulting in substantial saving of material and
lo thermal energy, remarkably improved operational efficiency
and reduced expenditure required for installing the menu-
lecturing facilities being assured. Thus, a required Solon-
Dracula billet is manufactured at a substantially reduced
manufacturing cost.
Next, description will be made below as to a method of
manufacturing a cylindrical billet in accordance with the
, third embodiment o-E the invention with reference to Figs.
12 to 18.
In Fig. 12 Jon which two sets of conventional horizontal
type continuous casting stands are schematically illustrate
Ed reference numerals 61 and 62'designate first and second
casting molds disposed in a spaced relation at a certain
distance kept there between, said casting molds 61 and 62
being formed with openings aye and aye having a semi- -
circular cross-sectional configuration as illustrated in
,
- 23 -
SLY
Fig. 13, reference numerals 63 and 64 do cast slabs horn-
zontally drawn from the first and second casting molds 61
and 62, each of said cast slabs 63 and I having a semi-
circular cross-sectional configuration, reference numeral
65 does a rotatable mandrel extending in the longitudinal
direction of the manufacturing facilities between both the
first and second casting molds 61 and 62, reference numeral
66 does two groups of guide rollers for gradually thrusting
the cast slabs 6.3 and 64 toward the mandrel 65 until the
end faces aye of the cast slab 63 come in contact with the
associated end faces aye of the cast slab 64, reference '
numeral 69 does an electro-slag welding apparatus for weld-
in together both the end faces aye and aye of the cast
slabs 64 and 64 and reference numeral 71 does plural pairs
of concave drum shaped sizing rollers arranged in a spaced
relation in the axial direction to reduce the thickness of
' the thus formed cylindrical billet 72 in cooperation with
the mandrel 65 under the influence of rolling force impart-
Ed thereby, the direction of the axis of each pair of said
sizing rollers 71 being deviated from that of the adjacent
pair by 90 degrees.
Both the end wall parts 61b and 62b of the openings aye
and aye of the first and second casting molds 61 and 62 are
inclined relative to the bottom of the casting molds so as
to form a V-shaped welding groove 75 between both the end
- 24 -
~23~Z~13
faces of the cast slabs 63 and 64 illustrated in Fly 16.
Alternatively, both the end wall parts 61b and 62b of the
openings aye and aye may be inclined so as to form another
type of V-shaped welding groove 76 as illustrated in Fly.
17.
Next, description will be made below as to how the
method in accordance with the third embodiment of the invent
lion is practiced with the aid of the manufacturing facile-
ties as constructed in the above-described manner.
First, a pair of semi-circular cast slabs 63 and 64 with
the end faces inclined are drawn from a pair of casting -I
molds 61 and 62 in the horizontal direction and they are
then -trusted gradually toward the rotating mandrel 65 by
means of the group of guide rollers 66 until both the end
faces aye and aye of the cast slabs 63 and 64 come in abut-
mint against one another while they are conveyed forward.
Next, the end face aye of the cast slab 63 is welded
with the end face aye of the cast slab 64 with the aid of
the electro-slag welding apparatus 69 as illustrated in Fix.
16 and thereby a cylindrically formed cast slab, that is,
cylindrical billet 72 is produced. Since welding material
or molten metal to be added to the V-shaped welding groove
during welding operation is supplied from the same material
supply source as that for the cast slabs 63 and 64, it is
assured that the cylindrical billet 72 has an uniform inner
- 25 -
3L23~Z~3
structure. When the cast slab has an inclined face as if-
lust rated in Fig. 15, welding is effected in the cross-
sectional form as illustrated in Fig. 17~
Next, the cylindrical billet 72 is subjected to thick-
news reduction by thrusting it against the mandrel 65 Bohemians of the plural pairs of sizing rollers 71 under the
influence of rolling force imparted thereby while the Solon-
Dracula billet 72 is conveyed and the sizing rollers 71 are
rotated. On completion of thickness reduction the Solon-
Dracula billet 72 has a metallurgically uniform inner struck
lure. - --
Since the mandrel 65 is caused to rotate during the
forming step for the cylindrical billet 72, there is no
fear of causing the mandrel 65 to be stuck to the cylinder-
eel billet 72..
When the cylindrical billet 72 is displaced away from the free end of -the mandrel 65 by a certain distance, it is
cut to a predetermined length by operating a cutting device
which is not shown in the drawing. Thus, a required Sweeney-
Dracula billet.haviny the predetermined length- is obtained
inch the method in accordance with this embodiment is
practiced by using a plurality of arched cast slabs which
are horizontally drawn from a plurality of casting molds in
accordance with the conventional horizontal type continuous
casting process, the cross-sectional configuration of said
- 26 -
1~30~8
cast billets and opening of said casting molds being keenest-
tuned by a part of the annular cross-sectional configuration
of the cylindrical billet which is equal to a fragment ox-
twined by dividing it by the number of cast slabs, it is identical to the foregoing embodiments in respect to the
fact that the cast slabs are welded together in a side-to-
side relation while they are cylindrically bent around the
rotating mandrel by means of the guide rollers and therefore
the same inventive effects as those in the foregoing embody-
mints are obtainable. Accordingly, the method in accordance with this embodiment does not require -the steps of blooming,
billet heating and piercing each of which constitutes an en-
sential step for practicing the conventional method, result-
in in substantial saving of material and thermal energy,
remarkably increased working efficiency and reduced expend-
lure required for installing the manufacturing facilities
being assured. Accordingly, cylindrical billets are menu-
lectured at an inexpensive cost.
In the above mentioner embodiment a cylindrical billet
is produced by welding together two cast slabs each of which
has a semi-cylindrical corss-sectional configuration ox-
twined by cutting a cylinder to two halves along a plane
extending through the axis of the cylinder, but the invent
lion should not be limited only to this. alternatively,
the method may be practiced by using more than 2 cast slabs,
- 27
)2~8
for instance, 3 to 5 cast slabs and welding them together in
a slde-to-side relation, etch of said cast slabs keenest-
tuning a longitudinally extending fragment of the cylindric-
at billet.
Next, description will be made below as to a method of
manufacturing a cylindrical billet in accordance with the
fourth embodiment of the invention with reference to Fig. 19.
In Fig. lo on which a conventional horizontal type con-
tenuous casting stand is schematically illustrated by way of
a perspective view reference numeral 81 designates a tune
dish, reference numeral 82 does an immersion type nozzle -
reference numeral 83 does a casting mold, reference numeral
84 does a flat cast slab horizontally drawn from said cast-
in mold 83, reference numeral 85 does a first concave drum
shaped roll disposed above said cast slab 84 at the position
located in the vicinity of said casting mold 83, reference
numeral 86 does a second concave drum shaped roll disposed
above the cast slab 84 at the position located downstream
of said first roll 85, reference numeral 87 does a press
work device including an upper die half aye and a lower die
half 87b and reference numeral 88 does a mandrel in the
from of a rod extending through the central part of said
press work device 87.
Specifically, the first roll 85 is located at the post-
lion where the cast slab 84 is subjected to plastic
- 28 -
I [)~
deformation against few resistance after leaving the cast-
in mold 83 and rolling operation is carried out by depress
sing the first roll 85 having a concave rolling surface on
the upper surface aye of the cast slab 84 so that the
latter is rolled down to the arched configuration core-
sponging to the concave rolling surface of the first roll
85. The second roll 86 is intended to additionally roll
down the upper arched surface aye of the cast slab 84 which
has subjected to rolling operation at the first roil 85 to
the semi-circular cross-sectional configuration as illicit-
rated at the right end part of the drawing. It should be
noted that a plurality of conventional guide rollers (not
show)- are arranged below the cast slab 84 at the position
located opposite to both the first and second rolls 85 and
86 so as to inhibit an occurrence of bending of the cast
slab 84.
When the cast slab 84 having the semi-circular cross-
sectional configuration is displaced away from the second
roll 86 by a certain distance, it is cut to a predetermined
length by operating a cutting device (not shown). -Thus,-
cast slabs 90 having the semi-circular cross-sectional con-
figuration are successively produced in that way. Next,
two cast slabs 90 having the semi-circular cross sectional
configuration and cut to the predetermined length are on
the cavity having the semi-circular cross-sectionaI
- 29 -
1230~
configuration corresponding to that ox the cast slab 90 in
-the upper and lower die halves aye and 87b of the press work
device 87 and thereafter the upper die half aye is super-
imposed on the lower die half 87b in such a manner that the
bottom aye of the one east slab 90 is located opposite to
that of the other east slab 90 and thereby a cylindrical
configuration is formed by two eat slabs. At this moment
the east slabs 90 laid on the cavities in the press work
devise 87 are kept still hot and therefore an axially ox-
lo tending recess having a semi-circular cross sectional con-
figuration is easy to be formed on the bottom 90 of each
- of the east slabs 90 by way of the steps of disposing a
mandrel 88 between both the east slabs 90 along the center
axis of the latter and depressing the upper die half aye
with the aid of a press machine which is not shown in the
drawing. After completion of press working the mandrel go
is removed from the press work device 87 and the latter is
then disassembled. Thus, two arched cast slabs 91 are ox-
twined each of which is formed with an axially extending
recess having a semicircular cross-seetional configuration
along the center axis thereof. Next, one arched cast sly
91 is superimposed on the other one in such a manner their
bottom surfaces aye are located opposite to one another
and jointing operation is carried out along the contact
line 92 extending between both the arched cast slabs 91.
- 30 -
~,'23~21~
Forging, rolling or welding is employed for jointing opera-
lion. As a result a cylindrical body, that is, cylindrical
billet 93 as illustrated in the drawing is obtained. Metal-
fig material or molten metal to be added to the jointed area
should be supplied from the same material source as that for
the original cast slabs. In other words metallic material
to be added should be the same material as that of the origin
net cast slabs.
Since the cylindrical billet 93 still has a considerably
lo high temperature, a required seamless pipe 94 can be easily
made from the cylindrical billet 93 by employing thickness
reduction rolling, extracting, drawing or the like process
without any necessity for reheating or the like step,
In the above-mentioned embodiment cylindrical billets
are manufactured with the aid of a conventional horizontal
type continuous casting stand but the present invention
should not be limited only to it. Alternatively, a vertical
type continuous casting stand may be employed or manufac-
luring cylindrical billets,
' Since the method in accordance with this embodiment is
practiced by way of the steps of roll forming a cast slab
drawn from a casting mold to the semi-circular configure-
lion at a time when it has few resistance against deform-
lion, placing one cast slab having a semi-circular cross-
sectional configuration on the bottom of the other cast slab
~23~
having a semi-circular cross-sectional configuration in
such a manner as to form a circular cr~ss-sectional con-
figuration with a mandrel interposed there between along
the center axis, press working the superimposed assembly
of two cast slabs to form two arched cast slabs with a
recess having a semi-circular cross sectional configuration
extending along the center axis and finally jointing to-
getter the superimposed assembly of two arched cast slabs
by carrying out jointing operation along the contact line
extending there between so that a cylindrical billet is pro-
duped, there is no necessity for practicing the steps of -
- blooming, billet heating and piercing each of which con-
statutes an essential process part for the conventional
method, resulting in substantial reduction in installation
of manufacturing facilities and consumption of thermal
energy being assured Thus, cylindrical billets can be
manufactured at an inexpensive cost.
t has been found with respect to the conventional
method that substantial reduction in yielding rate is
I caused during the steps of blooming and piercing. On the
other hand, there occurs no reduction in yielding rate when
the method in accordance with this embodiment is employed.
As a result remarkably improved yielding rate and menu-
lecturing at an inexpensive cost are achieved.
Since a cylindrical billet manufactured in accordance
- 32 -
~:30~
with this embodiment of -the invention has inner and outer
surfaces which are very smooth and exhibit good appearance
owing to the fact that a cast slab prepared by the convent
tonal continuous casting process has front and rear sun-
faces which are very smooth and exhibit good appearance,
no secondary processing is required or it can be minimized.
Further, the method of the invention makes it possible
to easily produce a cylindrical billet having various
dimensions ranging from a combination of thinner thickness
and smaller diameter to a combination Go heavier thickness
and larger diameter merely by changing the thickness of cast
slab the configuration of roll, dimensions of press work
device and the outer diameter of mandrel. Particularly, it.
is possible to manufacture a cylindrical billet having any
special size which could not be processed by the convent
tonal method.
Since the-method of the invention is practiced by way
of the steps of roll forming a cast slab having a constant
thickness to the semi-circular configuration at a time when
few resistance appears against deformation, forming on each
of the roll formed cast slabs an axially extending recess
having a semi-circular cross-sectional configuration with
the aid of a mandrel and a press work device and jointing
together two arched cast slabs superimposed in the form of
a cylinder so that a cylindrical billet is produced, it is
- 33 -
~23~
assured that manufacturing is carried out with reduced
rate of occurrence of irregular thickness, improved inner
structure, particularly reduced occurrence of an isotropy and
highly increased concentricity and dimensional accuracy and
moreover subsequent steps of manufacturing a pipe are easily
practiced with a part of conventional processing steps elf-
minuted therefrom because a seamless pipe can be made from
the cylindrical billet without any necessity for reheating
or like step.
Manufacturing facilities are very simple in structure and
require small space so that they can be equipped with access --
stories and instruments in a compact manner.
Tune method of the invention should not be limited only
to manufacturing of steel pipes but it may be successfully
applied to a case where pipes are made from metallic Metro-
at other than steel, for instance, titanium.
As will be readily understood from the above descrip-
-lion, characterizing features of the method of the invent
lion are that a large part of the conventional processing
steps can be neglected, seamless steel pipes-having various
combinations of wall thickness and diameter are manufac-
lured at an inexpensive cost and the method is effectively
applicable either to a case where small number and many
kinds of pipes are manufactured or to a case where large
number and small kinds of pipes are manufactured.
- 34 -
Lucy
Finally, description will be made below as to a method
of manufacturing a cylindrical billet in accordance with
the fifth embodiment of the invention with reference to
Fox and 21.
In Fig. 20 on which a conventional vertical type con-
tenuous casting stand is schematically illustrated by way
of a perspective view reference numerals Lola and loll
designate a pair of casting molds disposed in a spaced no-
lotion at a certain distance kept there between and reference
numerals aye and 102b do a solid cast slab having a equate
cross-sectional configuration respectively which is drawn
from said casting molds Lola and loll in the downward direct
lion. Both the cast slabs aye and 102b are guided by
means of a plurality of guide rollers (not shown) disposed
below the casting molds Lola and loll in such a manner that
they come close to one another. While the cast billets
aye and 102b are guided by means of the aforesaid guide
rollers, they are cooled down to a certain extend by operate
in a cooling device (not shown) so that any unsolidified
part of molten metal disappears. Further, a plurality of
grooving rollers 103 are disposed in a spaced relation
along the center line of the inside surface of both the
cast slabs aye and 102b at the position where very few no-
distance appears against deformation and thereby plastic
deformation is readily carried out, whereas a plurality of
- 35 -
1~30;;~
concave drum shaped forming rollers 104 are disposed in a
spaced relation along the outside surface ox both the cast
slabs aye and 102b at the position located opposite to the
grooving rollers 103 for the purpose of roll forming the
cast slabs aye and 102b to the semi-circular cross-sectional
configuration. Thus, the cast slabs lQ2a and 102b to be
roll formed are sandwiched between the grooving rollers 103
and the forming rollers 104. As it apparent from the drown
ins, each of the grooving rollers 103 includes a support
shaft 108 and a pair of width defining rollers 105 and 106
fixedly secured to both the ends of said support shaft 108 3
so that the grooving roller 103 is fixedly mounted on the
support shaft 108 at its central position to rotate together
with the width defining rollers 105 and 106. Each of the
grooving rollers 103 is located at a right angle relative
to the inside surface of the cast slabs aye and 102b to be
roll formed so that a longitudinally extending groove 108
is roll formed thereby while the cast slabs aye and 102b
move downward and the grooving rollers 103 are rotated
under the influence of thrusting force toward the inside
surface of the cast slabs aye and 102b. During the roll
forming step the pair of width detaining rollers 105 and
106 are rotated by both the side surfaces of the cast slab
in order to inhibit lateral expansion of the cast slab and
keep its width constant. On the other hand, the forming
- 36 -
~LX3~ 18
rollers 104 located opposite to the associated grooving not-
tens 103 with the cast slab interposed there between are
trusted toward the outside surface of the cast slab so that
it is gradually roll formed to the semi-circular cross-
sectional configuration. On completion of roll forming thickest slabs aye and 102b assume a semi-cylindrical configure-
lion and when they pass through a pair of uniting rollers
107 they become semi cylindrical billets aye and 109b. It
should be noted that the plural groups of rollers 103, 104,
105 and 106 are disposed at a certain distance kept between
the adjacent ones in the direction of movement of the cast
slabs aye and 102b in such a manner they assume a sub Stan-
tidally semi-cylindrical configuration before their bottom
surfaces come in contact with one another. Further, it
lo should be noted that the grooving rollers 103 are so design-
Ed that their width becomes wider and their peripheral con-
figuration becomes more semi-circular as they are located
lower.
A pair of concave drum shaped uniting rollers 107 having
a larger diameter are disposed at the position where both
the semi-cylindrical billets aye and 109b come in contact
with one another so that their bottom surfaces are jointed
together under the influence of thrusting force imparted by
said pair of uniting rollers 107 to form a cylindrical bit-
let. After the jointed semi-cylindrical billets aye and
~L~30~:~8
lob pass through the pair of uniting rollers 107, a no-
squired cylindrical billet 110 is obtained. Both the semi-
cylindrical billets Lola and lob are preferably jointed
by welding, origin or the like process. When they are
jointed together by welding operation, metallic material or
molten metal to be added should be supplied from the same
material supply source as that for the original cast slabs.
When the cylindrical billet 110 is displaced downwardly
of the pair of uniting rollers 107 at a predetermined disk
lance away from the latter, it is cut to a predetermined length by operating a cutting device (not shown) whereby a I-
cylindrical billet 111 having the predetermined length is
obtained. Since the thus produced cylindrical billet 111
still has a considerably high temperature, it is subjected
to subsequent working such as thickness reduction rolling,
drawing, extruding or the like without any necessity for
reheating whereby a seamless steel pipe 112 is produced.
This embodiment is different from the foregoing ones in
respect of the step of forming a longitudinally extending
recess having a semi-circular cross-sectional configuration
but the former is identical to the latter in respect of the
fact that a cast slab is deformed to the semi-circular con-
figuration with the aid of a plurality of forming rollers
at a time when it has few resistance against geometrical
deformation. Accordingly, the substantially same inventive
- 38 -
~LZ3~ Lo
effects as those in the foregoing embodiment are assured
also with respect to this embodiment.
Although the present invention has been fully described
above by way of several preferred embodiments with refer-
once to the accompanying drawings, it should be of courceunderstood that the invention should not be limited only to
them but various changes or modifications may be made in a
suitable manner without any departure from the spirit and
scope of the invention as defined in appended claims. Since
the such changes ox modification do not depart from the
scope of the invention, they should be construed as included -
therein.
- 39 -
