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Патент USA US2023776

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Dec. l0, 1935.
Filed May 4, 1934
Kia-kf» ,
Patented Dec. 10, 1935
Adolf Weiing, Witten/Ruhr, Germany, assignor
to Tubus A. G., Zurich, Switzerland l
. Application May 4, 1934, Serial No. 723,842
In Germany January 13, 1933
3 Claims.
This invention relates to the manufacture of
seamless tubing and similar elongate metallic ar
(Cl. 29-156)
particularly from ferrous metals, such as steels,
by a process which confers the advantages of
extrusion procedures but in which larger billets
may be operated upon, to provide greater lengths
of product, than economically practical hereto- 5
fore,- in which the exaggerated mandrel wear here
tofore encountered in extruding large size billets
is minimized, which is rapid, readily operated, and
otherwise embodies procedural and economic ad
vantages, such as the use of standard types of 1n'
ticles, such as solid sections, e. g., rods
For ease of reference and for purposes of i1
5 lustratlon the productionof seamless tubes may
be referred to, although the invention is not limit
ed thereto. 4In ordinary processes of producing
seamless tubes> a multiplicity of steps are nec
essary, including the forming of a billet, heating
10 the billet, piercing the heated billet, and elon
gation of the pierced billet in one of the conven
tional apparatuses, such as a pilger mill. There
after the blank is commonly subjected to a reduc
ing operation, to bring it to desired size, and
for this purpose reheating of the elongated blank
is necessary prior to reduction, and, itmay be,
In accordance with this invention seamless
tubes and the like articles of Vgreat length relative
to their section are made by extruding a heated
billet to forman oversized article in a heated 15
condition, and while the article isthus heated l
reducing it to the desired size. Referring to the
also between various steps of the reducing op » manufacture ofl seamless tubes as anl example, a
eration. Such procedures are disadvantageous heated billet of metal is extrudedin a suitable
` because of the multiplicity of steps and the addi . extrusion press, using ya mandrel and die of
tional heating operation required for reducing,
20 which adds to the cost burden, materially slows such size as to produce a tubek of greater diameter
than that desired. This oversized tube exudes
down production, and may be otherwise objec
from the die opening of the press in a highly heat
ed condition, and I have, discovered, and it is
The extrusion process is theoretically more at
-upon this that my invention is predicated in part, 25
tractive because it affords a means of producing
2 Ul seamless 'tubes in a single step. This operation that the heat thus inherently` in the tube as ex
truded is suiiicient to permit «it to be reduced to
ls advantageous not only for that reason, but also the desired size by »subjecting it, without reheat- "
because it is applicable, generally speaking, to ing, to a suitable reducing or sinking operation, for
all grades of common and alloyed steels. By vir
example, in a sink mill, or a suitable‘pilger or 30
tue of these features the extrusion production of other mill, various types of which are known in
30 seamless tubes and the like elongate articles
should be cheaper than the processes ordinarily
The accompanying drawing is a diagrammatic
used, such as those referred to hereinabove. The 1 view, partly in section, illustrative of `one embodi
greatest economy would follow from the use of ment of the method provided by the invention and
large billets, for thereby'fewer operations would
35 produce longer tubes than Where small billets showing the formation of an oversized tube by
extrusion and its conversion to a sized tube with
are extruded. When it is attempted tofuse large
billets, however, there is encountered the serious
drawback that as the size of the billet is increased
in the production of a tube of given size, the wear
40 and tear upon the mandrel is definitely and mate
rially greater, as compared with the production
of tubes of the same size from smaller billets.
This factor may become so serious in attempting
to use large billets as to’oiîset other advantages
of the extrusion process.
It is a major object of this invention to pro
duce seamless tubes andother elongate articles
of relatively small section, e.' g., not more than
about three inches in diameter or greatest width,
.out intermediate heating.
In order to utilize the residual heat of extru
sion to avoid reheating for the sinking step, the ¿o
press must operate at high punch speeds, or, as
an equivalent„the extruding time must be short.
My experience thus far has shown that the most
advantageous kresults are obtained by extruding
at a punch speed of at least 3 inches per second, 45
or by performing the extrusion proper within 2
or 5 seconds. As a result of the use of high punch
speeds, i. e., short extrusion time, the extruded
oversize tube will emerge from the press at about
the temperature of the billet when inserted into 50
- the press, or even somewhat higher in tempera
ture,'which suflices to permit it to be subjected to» the extrusion operation. The reducing means
shown in the vdrawing comprises a sink mill.
vthe reducing, or sinking, Operation without inter
mediate reheating. Since the temperature _of the schematically indicated at l5, which operates
extruded article depends in part at least, upon upon the oversized and heated tube in the known
manner to bring it to the desired external diam- 5
the pressing speed, it is possible,~by suitable reg
while elongating it'and increasing its wall
ulation of the punch speed to the size of billetand
thickness somewhat. In the drawing the sized
size of extruded article, to regulate, and even in
tube is' shown at 6a emerging from the sink
crease, within certainV limits, the temperature of mill.
the extruded tube, with concomitantadvantage.
The invention is especially useful in the pro- l0
duction of articles from metals requiring high`
extrusion temperatures, such as steelsand other
ferrous metals. Asan example of the invention
In the preferred practice ofthe invention as
applied to tubes,` the extrusions is conducted to
provide a wall thickness approximately the same
as that desired in the finished tube, the outer
diameter of ¿_ the extruded blank being greater (i. e., ¿ _
oversize) - than lthat ~desired.I
_ reference may be made tothe production of _,
l -inch` seamless steel tubes.'r According to the l5
extrusion processes as applied heretofore to such
duction to size it isthus possible to make long ar- ` purposes such tubes would be produced using ’a
ticles from larger billets lwith less mandrel wear mandrel having a diameter of 1118 inch, and a.
Bysuch extrusion-of an oversized tube and _re-f
matrix die ring having an inner diameter of 1%
20 than would result in extruding the same article to
` inch. These small size to'ols, especially the com- 20
size from a billet of the .same size, soV that mandrel>
costs aremateriallyreduced; _In thesinking of,- `paratively thin mandrel, are worn so rapidly in
the extruded tube its length is increased, so that" - extruding steel that it is advisable, for reasons ,
the invention likewise results in the production of economy, to use billets which do not exceed
25 of tubes of greater length than have heretofore »about 40 lpounds in weight. 'Ihe tube extruded
been economically producible with the ordinary «from'such a billet and with such tools will be 25
extrusion procedures as> practiced heretofore.
about 23 feet long, weighing about 37.5 pounds.` "
`Throughgreductio'n of the oversized tube directly"
` In the practice of this invention tubes of the
same final 'size are made by extruding a heated _
after extrusion .use is madeof theheat devel
30 oped in the ¿extrusion step,;fso that the reducing _ billet-to form an> oversize tube having an outer
diameterî of ‘2% inches and a wall thickness 30
»_ , operation is possible without the intermediate re
heatings that have beenunavoidable in the >com
monly applied rolling and sinking processes of
A y"making seamless tubes, ,such as theL'well-known
_Mannesmann or Stiefel processes, as noted here
of about 1/8 inch. For a'tube of such size there
may befused satisfactorily a billet weighing 104
pounds, which provides an extruded oversize
tube 31_feet long. This is directly reduced, with
inabove. likewise, the invention furthenreduces
out intermediate reheating, toa 1 linch tube, and 35
step combines in one the priorjseparate pierc
the tube Willïbe about 6_0 feet'in length.y The “ad- ‘
vantages flowing from the invention will be rec
the number of steps required, since the extrusionv v after the sinking operation has been completed ,
ing and elongating operations, and eliminates the
ognized from the foregoing figures.
40 reheating.v The invention Ytherefore overcomes
` 'the economical disadvantagesvof both -procedures
A further advantage ofthe process provided 40v
Í by this invention resides in the fact that tubes
, andr provideszfurther advantagesuover both.” '
’ ' of ' yvarious
f The inventionfsmay be described further with
y reference tothe drawing-in which I represents
final diameter can be producedfro'm"
the same oversize tubes, _i. e., using billetsand,
extruding tools of the same size, the only differ
rence 'residing in the extent of the reducing, or ß
an extrusion -pressfadapted to extrude >tubes
rapidly, e.:g.‘ at highy punch‘speeds, as described
hereinabove, suitably of the type 'shown in reissue ` sinking,
llifhen4 changing rthe 'final
tube dimension, therefore, adaptation of the re
Patent No. 19,474 _to :Fritz Singer, reissued lFeb
ruaryv 19, 1935;?15In the form of press'shown'a - ducing mill only is required. For instance, using
,50 billet >2 is disposed., in 'a container‘3 havinga the 2%-inch' extruded tube referred td in the
~ >matrixrdie 4_ atits lower end. The container and foregoing example it is possible to produce all 5°
gauges of tubing below 2 inches merely byap
y'matrix die are supported ïbya ñxed table 5 pro
propriate vadaptation of the reducing mill, or, “
vided With'acentr'ally disposed bore forV egress
of the extruded "tube 6».
alternatively, by providing several reducing mill
through ‘ " 'units.~„ Other advantages will berecognized by
A mandrel 'l extends
55 downwardly from a ~ mandrel* carrier 8
those familiar with the art. _'
a plunger llî connected lto a hollow plunger >car
rier l0 slidably mounted-'inthe upper part of the
I' j'press= frame andin which the mandrel carrier
moves as a piston, asmay beseen from‘the draw
According to the provisions of the Patent Stat
utes,~I _have explained thefprincipleof my in- I
vention, andy have described what I,_now con- `
ing." The plunger and mandrel are actuated’ vsider _to represent its best embodiment. How
ever, Iv desire'to have it understood than-within .o
-the scope of the appended claims-,the invention
through a pitman Il connected at its lower end
-to mandrel carrier V8 and at its upper end to' a
may be practiced otherwise -than asspecifically `
:crank -|2 driven by a crank shaft I3. The'ex
' truded tube lîemergesffrom the ypress through
>the bore in table» 5 and is guided away from the ` '
press by a vchannel‘ïifi.
The tubeïöis oversized, byappropriate selec
" l. A method `of producing seamless tubes the u
greatest sectional width offwhich is not more ,
tionof'the mandrel and die, relative to the ñnal 'than about three inches comprising piercing a
and> by vappropriate operation -of the
70 press, -as by lhigh punch, or plungenspeed, -it
, emerges in highly heated condition, as_.describ'ed
hereinabove. lThe heated tube then passes di
~ rectly,'i. e., 'without intermediate reheating, to »
means for hot reducing it lto‘ñnished `size' using .
-the heatl inherently in the túber'as a' result oi’
¿heated 1oversiz'ed'tube, and reducing said tube
to desired size utilizing the _residual heat-of ex- "
' »2. A method of producing seamless tubes the
greatest sectional width of which is not more than u
about three inches comprising piercing a heated
billet and extruding the pierced billet through
a die at an average punch speed of at least three
inches per second to form a highly heated tube
having approximately the desired wall thickness
but oversized as to external diameter, and reduc
ing the article to desiredvsize utilizing the resid
ual heat of extrusion.
3. A method of producing seamless tubes the `
l0 greatest sectional width of which is not more
than about three inches comprising piercing a
heated billet and extruding the pierced billet
through a die at an Aaverage punch speed of at
least three inches per second to form a. highly
heated oversized tube, and subjecting it to a
sink mill, utilizing the residual heat of extrusion
in the tube, to reduce and elongate the oversized
article to bring it to desired size.
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