EP1375019B1 - Thick-walled small diameter pipe producing method - Google Patents
Thick-walled small diameter pipe producing method Download PDFInfo
- Publication number
- EP1375019B1 EP1375019B1 EP02705123A EP02705123A EP1375019B1 EP 1375019 B1 EP1375019 B1 EP 1375019B1 EP 02705123 A EP02705123 A EP 02705123A EP 02705123 A EP02705123 A EP 02705123A EP 1375019 B1 EP1375019 B1 EP 1375019B1
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- EP
- European Patent Office
- Prior art keywords
- tube
- small diameter
- final
- drawing process
- cutting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C1/00—Manufacture of metal sheets, metal wire, metal rods, metal tubes by drawing
- B21C1/16—Metal drawing by machines or apparatus in which the drawing action is effected by other means than drums, e.g. by a longitudinally-moved carriage pulling or pushing the work or stock for making metal sheets, bars, or tubes
- B21C1/22—Metal drawing by machines or apparatus in which the drawing action is effected by other means than drums, e.g. by a longitudinally-moved carriage pulling or pushing the work or stock for making metal sheets, bars, or tubes specially adapted for making tubular articles
- B21C1/24—Metal drawing by machines or apparatus in which the drawing action is effected by other means than drums, e.g. by a longitudinally-moved carriage pulling or pushing the work or stock for making metal sheets, bars, or tubes specially adapted for making tubular articles by means of mandrels
- B21C1/26—Push-bench drawing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C1/00—Manufacture of metal sheets, metal wire, metal rods, metal tubes by drawing
- B21C1/16—Metal drawing by machines or apparatus in which the drawing action is effected by other means than drums, e.g. by a longitudinally-moved carriage pulling or pushing the work or stock for making metal sheets, bars, or tubes
- B21C1/22—Metal drawing by machines or apparatus in which the drawing action is effected by other means than drums, e.g. by a longitudinally-moved carriage pulling or pushing the work or stock for making metal sheets, bars, or tubes specially adapted for making tubular articles
- B21C1/24—Metal drawing by machines or apparatus in which the drawing action is effected by other means than drums, e.g. by a longitudinally-moved carriage pulling or pushing the work or stock for making metal sheets, bars, or tubes specially adapted for making tubular articles by means of mandrels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
- B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
- B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
- B21C37/30—Finishing tubes, e.g. sizing, burnishing
Definitions
- the present invention relates to a method for manufacturing a thick wall small diameter tube, and more particularly to a method for manufacturing a thick wall small diameter tube capable of being used suitably as a fuel injection tube for a diesel engine, in an efficient manner.
- a thick wall small diameter tube used as a fuel injection tube for a diesel engine is required to have a high degree of smoothness on the inner circumferential surface of the tube, in order to reduce the flow resistance in the tube and to prevent blocking of the injection nozzle. Furthermore, it is also required that defects, and in particular, fine cracks, in the inner circumferential surface of the tube, are reduced, in such a manner that the tube is able to withstand the repeated fatigue of high pressure.
- the thick wall small diameter tube used in this application is normally based on a seamless stock tube formed by hot rolling, such as Mannesmann mill piercing, rolling in a mandrel mill, and the like.
- This seamless stock tube is then set to a prescribed diameter by a cold drawing process involving repetition of a tube drawing process using a draw bench, or the like, and a heat treatment process.
- the tube member adapted to the desired diameter is then cut to a product dimension, thereby completing manufacture of a thick wall small diameter tube for use as a fuel injection tube in a diesel engine.
- a black skin layer containing cracks, and indent-shaped wrinkles caused by the Mannesmann mill piercing process, the mandrel mill rolling, or the like, involved in the hot rolling process form on the inner and outer surfaces of the seamless stock tube.
- fine cracks caused by the repeated tube drawing processes using a draw bench, or the like, followed by heat treatment processing also form on the inner and outer surfaces of the tube member that has been adjusted to the desired diameter.
- Japanese Patent Publication No. S51-21391 discloses a method wherein the black skin layer on the inner circumferential surface of a seamless stock tube is removed by mechanical cutting, before the seamless stock tube formed by hot rolling is drawn into a thick wall small diameter tube forming product.
- Japanese Patent Laid-open No. H5-154536 discloses a method wherein defects, such as fine cracks, and the like, which are present in the inner circumferential surface of the tube to be processed, are removed by mechanical cutting or grinding before the final tube drawing process, or a tube drawing process proximate thereto.
- Japanese Patent Laid-open No. H9-57329 discloses a method wherein the inner circumferential surface of a seamless stock tube obtained by hot rolling is ground by a shot blasting process, either before the tube drawing process, or at an intermediate stage of a plurality of tube drawing processes.
- the process of cutting, grinding, or the like, of the inner circumferential surface of the tube described above is effective in manufacturing a thick wall small diameter tube having an inner surface that is smooth and free of defects, and in particular, cutting or grinding carried out at a stage as proximate as possible to the final stage of processing is very effective, since there is only slight generation of cracks, and the like, in the subsequent processing.
- the present invention was devised with the foregoing problems of the prior art in view, an object thereof being to provide a method whereby a thick wall small diameter tube, having an inner circumferential surface that is smooth and free of defects, which can be used suitably as a fuel injection tube for a diesel engine, can be manufactured in an efficient manner.
- the present invention is such that, in manufacturing a thick wall small diameter tube by performing a plurality of tube drawing processes on a seamless stock tube, prior to a final tube drawing process, the tube being processed is cut to a length whereby it will assume the product dimension by means of the final tube drawing process, and a cutting or grinding process is performed on the inner circumferential surface of the cut tube.
- the cutting or grinding process of the inner circumferential surface is performed at a stage where only the final tube drawing process remains, it is possible to provide a thick wall small diameter tube having an inner circumferential surface that is smooth and free of defects. Moreover, since the cutting or grinding process is carried out on a cut piece which has been cut to a length whereby it will assume the product dimension by means of the final tube drawing process, the length of the piece is short and the cutting or grinding process can be performed readily, in a highly accurate manner.
- this final tube drawing process can be carried out readily by means of a forging process using a pressing force created by a press, or a forging process using a parts former employed in the formation of various parts, such as bolts, nuts, or the like, for example, this process being carried out in a short period of time in comparison with a tube drawing process using a draw bench, as in the prior art, and furthermore, there being no need for chucking in order to perform drawing, thus allowing the product yield rate to be improved.
- Fig. 1 is a diagram showing a conceptual view of a method for manufacturing a thick wall small diameter tube relating to the present invention.
- Fig. 2 is a diagram showing a conceptual view of one example of a final tube drawing process.
- seamless carbon steel stock tube (JIS G 3455) having an external diameter of 34 mm and a wall thickness of 4.5 mm, formed by hot rolling involving Mannesmann mill piercing, rolling in a mandrel mill, or the like, is taken and is subjected to cold drawing consisting of repetitions of tube drawing work using a draw bench and a heat treatment process, as implemented in the prior art, thereby obtaining a tube member having an external diameter of 11 mm and a wall thickness of 2.0 mm (Fig. 1(a)).
- the steps of cutting or grinding the inner circumferential surface of the tube as performed in the prior art are carried out during this process, since they are easy to carry out when the diameter of the tube is still relatively large, but these are not essential steps in the present invention.
- the aforementioned tube member of 11 mm external diameter and 2.0 mm wall thickness is cut to a length of 150 mm by a cutting machine (see Fig. 1(b)).
- the length to which the tube member is cut is such that the tube will assume a product length after subsequent tube drawing processing.
- the object of the cutting or grinding according to the present invention is a short piece having a length of approximately 150 mm, as described above, and therefore these steps can be performed readily and in a highly accurate manner.
- the inner circumferential surface is such that the black skin layer formed during hot rolling has been removed completely from same, and furthermore, that defects (having a size of 50 ⁇ m or above) such as indent-shaped wrinkles arising during the tube drawing work, or fine cracks, or the like, formed on the basis of these indent-shaped wrinkles, have been removed completely.
- the cut piece which has undergone cutting or grinding on the inner surface thereof as described above is then subjected to a final tube drawing process in such a manner that the product dimensions of 8 mm external diameter, 2.0 mm wall thickness and 230 mm length are obtained (see Fig. 1(d)).
- this final tube drawing process is performed on a short tube of approximately 150 mm length, it is possible to carry out drawing and forming using a parts former, which is used in the formation of various types of parts, such as bolts, nuts, and the like.
- the tube to be processed A is inserted into a dice 1 having a pierce hole of restricted diameter, by means of press equipment using water pressure, hydraulic oil pressure or a clamp mechanism, and the tube to be processed A is drawn by means of a forging process.
- Element 3 in Fig. 2 is a plug which is inserted inside the tube to be processed A.
- This final tube drawing process is carried out in a short period of time in comparison with conventional tube drawing processes using a draw bench, and moreover, it requires no chucking for the purpose of drawing, and hence the product yield rate can be improved.
- the thick wall small diameter tube manufactured in this manner may contain slight cracks (of maximum size 10 ⁇ m) generated by the final tube drawing process, but it is a thick wall small diameter tube having an inner circumferential surface which is sufficiently smooth and free of defects, and it can be used appropriately as a fuel injection tube for a diesel engine.
- the method for manufacturing a thick wall small diameter tube according to the present invention is also applicable to thick wall small diameter tubes used in applications other than fuel injection tubes for a diesel engine, and may be employed appropriately for the manufacture of any thick wall small diameter tube having strict requirements with regard to the properties of the inner circumferential surface thereof.
- the method of the present invention may also be applied to the manufacture of thick wall small diameter tube of any type of steel, such as carbon steel, alloy steel, stainless steel, and the like.
- the final tube drawing process may be implemented by dividing it over a plurality of tube drawing steps.
- a thick wall small diameter tube relating to the present invention as described above, since a cutting or grinding process on the inner circumferential surface is carried out at a stage where only the final tube drawing process remains, it is possible to provide a thick wall small diameter tube having an inner circumference that is smooth and free of defects, in addition to which, since the cutting or grinding process is carried out on a cut piece that has been cut to a length whereby it will assume the product dimension by means of the final tube drawing process, then a merit is obtained in that, since the length of the piece is short, the cutting or grinding process can readily be carried out with good accuracy.
- the tube to be processed is cut to a length whereby it will assume the product dimension by means of the final tube drawing process, before the final tube drawing process, it is possible to carry out the final tube drawing process readily by means of a forging process using a pressing force created by a press, or by means of a forging process using a parts former employed to form various parts, such as bolts, nuts, or the like, for example, and this process can be carried out in a short period of time in comparison with a tube drawing process using a draw bench, as in the prior art, in addition to which, chucking for the purpose of drawing is not required and hence a merit is obtained in that the product yield rate can also be improved.
- the method for manufacturing a thick wall small diameter tube relating to the present invention is applicable to cases where thick wall small diameter tubes having strict requirements with respect to the properties of their inner surface, such as fuel injection tubes for a diesel engine, are manufactured in an efficient manner.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Metal Extraction Processes (AREA)
- Fuel-Injection Apparatus (AREA)
Description
The present invention relates to a method for
manufacturing a thick wall small diameter tube, and more
particularly to a method for manufacturing a thick wall
small diameter tube capable of being used suitably as a
fuel injection tube for a diesel engine, in an efficient
manner.
For example, a thick wall small diameter tube used as
a fuel injection tube for a diesel engine is required to
have a high degree of smoothness on the inner
circumferential surface of the tube, in order to reduce
the flow resistance in the tube and to prevent blocking of
the injection nozzle. Furthermore, it is also required
that defects, and in particular, fine cracks, in the inner
circumferential surface of the tube, are reduced, in such
a manner that the tube is able to withstand the repeated
fatigue of high pressure.
Here, the thick wall small diameter tube used in this
application is normally based on a seamless stock tube
formed by hot rolling, such as Mannesmann mill piercing,
rolling in a mandrel mill, and the like. This seamless
stock tube is then set to a prescribed diameter by a cold
drawing process involving repetition of a tube drawing
process using a draw bench, or the like, and a heat
treatment process. The tube member adapted to the desired
diameter is then cut to a product dimension, thereby
completing manufacture of a thick wall small diameter tube
for use as a fuel injection tube in a diesel engine.
However, in the case of the method of manufacture
described above, a black skin layer containing cracks, and
indent-shaped wrinkles caused by the Mannesmann mill
piercing process, the mandrel mill rolling, or the like,
involved in the hot rolling process, form on the inner and
outer surfaces of the seamless stock tube. Furthermore,
fine cracks caused by the repeated tube drawing processes
using a draw bench, or the like, followed by heat
treatment processing, also form on the inner and outer
surfaces of the tube member that has been adjusted to the
desired diameter.
Therefore, in order to obtain a tube member having an
inner circumferential surface which is smooth and free of
defects, cutting and grinding of the inner surface is
carried out at various stages.
For example, Japanese Patent Publication No. S51-21391
discloses a method wherein the black skin layer on
the inner circumferential surface of a seamless stock tube
is removed by mechanical cutting, before the seamless
stock tube formed by hot rolling is drawn into a thick
wall small diameter tube forming product.
Moreover, Japanese Patent Laid-open No. H5-154536 (US publication number: US-A-5 339 513)
discloses a method wherein defects, such as fine cracks,
and the like, which are present in the inner
circumferential surface of the tube to be processed, are
removed by mechanical cutting or grinding before the final
tube drawing process, or a tube drawing process proximate
thereto.
Furthermore, Japanese Patent Laid-open No. H9-57329
discloses a method wherein the inner circumferential
surface of a seamless stock tube obtained by hot rolling
is ground by a shot blasting process, either before the
tube drawing process, or at an intermediate stage of a
plurality of tube drawing processes.
Here, the process of cutting, grinding, or the like,
of the inner circumferential surface of the tube described
above is effective in manufacturing a thick wall small
diameter tube having an inner surface that is smooth and
free of defects, and in particular, cutting or grinding
carried out at a stage as proximate as possible to the
final stage of processing is very effective, since there
is only slight generation of cracks, and the like, in the
subsequent processing.
However, as the tube drawing process approaches the
final stage, the tube diameter becomes smaller and the
tube length becomes longer. Cutting or grinding the inner
circumference of a long and thin tube member, no
matter what the method employed for same, is a very
difficult task indeed. Moreover, since the task is very
difficult to perform, cutting or grinding is not carried
out satisfactorily, and in the final product inspection,
defects have been discovered in the inner circumferential
surface, in a considerable number of cases.
The present invention was devised with the foregoing
problems of the prior art in view, an object thereof being
to provide a method whereby a thick wall small diameter
tube, having an inner circumferential surface that is
smooth and free of defects, which can be used suitably as
a fuel injection tube for a diesel engine, can be
manufactured in an efficient manner.
In order to achieve the aforementioned object, the
present invention is such that, in manufacturing a thick
wall small diameter tube by performing a plurality of tube
drawing processes on a seamless stock tube, prior to a
final tube drawing process, the tube being processed is
cut to a length whereby it will assume the product
dimension by means of the final tube drawing process, and
a cutting or grinding process is performed on the inner
circumferential surface of the cut tube.
According to the method for manufacturing a thick
wall small diameter tube relating to the present invention
described above, since the cutting or grinding process of
the inner circumferential surface is performed at a stage
where only the final tube drawing process remains, it is
possible to provide a thick wall small diameter tube
having an inner circumferential surface that is smooth and
free of defects. Moreover, since the cutting or grinding
process is carried out on a cut piece which has been cut
to a length whereby it will assume the product dimension
by means of the final tube drawing process, the length of
the piece is short and the cutting or grinding process can
be performed readily, in a highly accurate manner.
Furthermore, according to the method for
manufacturing a thick wall small diameter tube relating to
the present invention described above, since the tube
being processed is cut to a length whereby it will assume
the product dimension by means of the final tube drawing
process, prior to the final tube drawing process, then
this final tube drawing process can be carried out readily
by means of a forging process using a pressing force
created by a press, or a forging process using a parts
former employed in the formation of various parts, such as
bolts, nuts, or the like, for example, this process being
carried out in a short period of time in comparison with a
tube drawing process using a draw bench, as in the prior
art, and furthermore, there being no need
for chucking in order to perform drawing, thus allowing
the product yield rate to be improved.
Reference to the "final tube drawing process" in the
present invention described above does not indicate a
single final tube drawing process, but rather, signifies a
final stage of tube drawing processes.
In other words, the operation of drawing a tube from
a seamless stock tube until it assumes a product dimension
is divided into a plurality of stages. This is because the
amount by which the tube can be extended in one drawing
operation, in other words, the rate of processing of the
external diameter per operation, Re [=[[external diameter
of tube before processing - external diameter of tube
after processing] / external diameter of tube before
processing] × 100], cannot be set in such a manner that
the tube drawing is performed in a single action, as the
pulling force exerted on the tube must be set at or below
the breaking load of the tube at its passage through the
dice. To give a representative example, in the case of a
carbon steel tube, drawing is implemented at an external
diameter processing rate Re = 20 - 30%.
Therefore, in the case of a carbon steel tube,
reference to "the final tube drawing process" as stated in
the present invention signifies a stage where the product
dimension is reached, using a tube drawing process where
the external processing rate for the subsequent drawing
operation is Re = 20 - 30%.
Consequently, cases where this final tube drawing
process is performed over a plurality of tube drawing
process steps, by means of a forging process using a parts
former, for example, are also included in the technical
scope of the present invention described above.
Fig. 1 is a diagram showing a conceptual view of a
method for manufacturing a thick wall small
diameter tube relating to the present invention.
Fig. 2 is
a diagram showing a conceptual view of one example of a
final tube drawing process.
Below, an embodiment of a method for manufacturing
thick wall small diameter tube according to the present
invention is described in detail, but the present
invention is not limited to the embodiment described
below.
Firstly, seamless carbon steel stock tube (JIS G
3455) having an external diameter of 34 mm and a wall
thickness of 4.5 mm, formed by hot rolling involving
Mannesmann mill piercing, rolling in a mandrel mill, or
the like, is taken and is subjected to cold drawing
consisting of repetitions of tube drawing work using a
draw bench and a heat treatment process, as implemented in
the prior art, thereby obtaining a tube member having an
external diameter of 11 mm and a wall thickness of 2.0 mm
(Fig. 1(a)).
Desirably, the steps of cutting or grinding the inner
circumferential surface of the tube as performed in the
prior art are carried out during this process, since they
are easy to carry out when the diameter of the tube is
still relatively large, but these are not essential steps
in the present invention.
Subsequently, the aforementioned tube member of 11 mm
external diameter and 2.0 mm wall thickness is cut to a
length of 150 mm by a cutting machine (see Fig. 1(b)).
Here, the length to which the tube member is cut is
such that the tube will assume a product length after
subsequent tube drawing processing.
Thereupon, cutting or grinding is performed on the
inner surface of the cut tube (Fig. 1(c)).
For the means for cutting or grinding the inner
surface of the cut tube, in addition to cutting or
grinding means such as a lathe, broaching machine, honing
machine, or the like, which are commonly known in the
prior art, it is also possible to use means such as shot
blasting, fluid grinding, or the like, or to incorporate a
suitable combination of the aforementioned means.
Whatever the means adopted, the object of the cutting
or grinding according to the present invention is a short
piece having a length of approximately 150 mm, as
described above, and therefore these steps can be
performed readily and in a highly accurate manner.
It is necessary that after cutting or grinding, the
inner circumferential surface is such that the black skin
layer formed during hot rolling has been removed
completely from same, and furthermore, that defects
(having a size of 50 µm or above) such as indent-shaped
wrinkles arising during the tube drawing work, or fine
cracks, or the like, formed on the basis of these indent-shaped
wrinkles, have been removed completely.
Thereupon, the cut piece which has undergone cutting
or grinding on the inner surface thereof as described
above is then subjected to a final tube drawing process in
such a manner that the product dimensions of 8 mm external
diameter, 2.0 mm wall thickness and 230 mm length are
obtained (see Fig. 1(d)).
Since this final tube drawing process is performed on
a short tube of approximately 150 mm length, it is
possible to carry out drawing and forming using a parts
former, which is used in the formation of various types of
parts, such as bolts, nuts, and the like.
For example, as shown in Fig. 2, the tube to be
processed A is inserted into a dice 1 having a pierce hole
of restricted diameter, by means of press equipment using
water pressure, hydraulic oil pressure or a clamp
mechanism, and the tube to be processed A is drawn by
means of a forging process.
This final tube drawing process is carried out in a
short period of time in comparison with conventional tube
drawing processes using a draw bench, and moreover, it
requires no chucking for the purpose of drawing, and hence
the product yield rate can be improved.
There is a possibility that the thick wall small
diameter tube manufactured in this manner may contain
slight cracks (of maximum size 10 µm) generated by the
final tube drawing process, but it is a thick wall small
diameter tube having an inner circumferential surface
which is sufficiently smooth and free of defects, and it
can be used appropriately as a fuel injection tube for a
diesel engine.
The foregoing description is related to an embodiment
of the present invention, but the present invention is not
limited in any way to the embodiment described above.
For example, the method for manufacturing a thick
wall small diameter tube according to the present
invention is also applicable to thick wall small diameter
tubes used in applications other than fuel injection tubes
for a diesel engine, and may be employed appropriately for
the manufacture of any thick wall small diameter tube
having strict requirements with regard to the properties
of the inner circumferential surface thereof.
Furthermore, it goes without saying that the method
of the present invention may also be applied to the
manufacture of thick wall small diameter tube of any type
of steel, such as carbon steel, alloy steel, stainless
steel, and the like.
Moreover, as stated previously, the final tube
drawing process may be implemented by dividing it over a
plurality of tube drawing steps.
According to the method for manufacturing a thick
wall small diameter tube relating to the present invention
as described above, since a cutting or grinding process on
the inner circumferential surface is carried out at a
stage where only the final tube drawing process remains,
it is possible to provide a thick wall small diameter tube
having an inner circumference that is smooth and free of
defects, in addition to which, since the cutting or
grinding process is carried out on a cut piece that has
been cut to a length whereby it will assume the product
dimension by means of the final tube drawing process, then
a merit is obtained in that, since the length of the piece
is short, the cutting or grinding process can readily be
carried out with good accuracy.
Moreover, according to the method for manufacturing a
thick wall small diameter tube relating to the present
invention, since the tube to be processed is cut to a
length whereby it will assume the product dimension by
means of the final tube drawing process, before the final
tube drawing process, it is possible to carry out the
final tube drawing process readily by means of a forging
process using a pressing force created by a press, or by
means of a forging process using a parts former employed
to form various parts, such as bolts, nuts, or the like,
for example, and this process can be carried out in a
short period of time in comparison with a tube drawing
process using a draw bench, as in the prior art, in
addition to which, chucking for the purpose of drawing is
not required and hence a merit is obtained in that the
product yield rate can also be improved.
As described above, the method for manufacturing a
thick wall small diameter tube relating to the present
invention is applicable to cases where thick wall small
diameter tubes having strict requirements with respect to
the properties of their inner surface, such as fuel
injection tubes for a diesel engine, are manufactured in
an efficient manner.
Claims (1)
- A method for manufacturing a thick wall small diameter tube, comprising the steps of,(i) prior to a final drawing process: performing a plurality of tube drawing processes on a seamless stock tube; cutting said processed tube to a length whereby it will assume the product dimension by means of said final tube drawing process; and performing a cutting or grinding process on the inner circumferential surface of said tube cut to said length; and thereafter(ii) carrying out said final tube drawing process by means of a forging process using the pressing force created by a press on said tube cut to said length of which said inner circumferential surface has been cut or ground.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001080073A JP3920581B2 (en) | 2001-03-21 | 2001-03-21 | Manufacturing method for thick thin tube |
| JP2001080073 | 2001-03-21 | ||
| PCT/JP2002/002349 WO2002074462A1 (en) | 2001-03-21 | 2002-03-13 | Thick-walled small diameter pipe producing method |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP1375019A1 EP1375019A1 (en) | 2004-01-02 |
| EP1375019A4 EP1375019A4 (en) | 2004-06-02 |
| EP1375019B1 true EP1375019B1 (en) | 2005-12-14 |
Family
ID=18936422
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP02705123A Expired - Lifetime EP1375019B1 (en) | 2001-03-21 | 2002-03-13 | Thick-walled small diameter pipe producing method |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP1375019B1 (en) |
| JP (1) | JP3920581B2 (en) |
| DE (1) | DE60208011T2 (en) |
| WO (1) | WO2002074462A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100468229B1 (en) * | 2002-01-16 | 2005-01-26 | 박종환 | Apparatus for valve of various type of forging method |
| CN114669623B (en) * | 2022-03-03 | 2024-09-27 | 合肥聚能电物理高技术开发有限公司 | Forming method of oval-section thin-wall non-magnetic stainless steel vacuum pipeline |
| DE102022114337A1 (en) * | 2022-06-08 | 2023-12-14 | Mannesmann Precision Tubes Gmbh | Method for producing a seamless precision steel tube, such precision steel tube and corresponding manufacturing system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3085762B2 (en) * | 1991-12-02 | 2000-09-11 | 臼井国際産業株式会社 | Method of manufacturing thick small-diameter tube |
| JP3152360B2 (en) * | 1991-12-04 | 2001-04-03 | 臼井国際産業株式会社 | Thick and small-diameter pipe inner peripheral surface cutting device |
| JPH09122795A (en) * | 1995-11-06 | 1997-05-13 | Daido Steel Co Ltd | Method for manufacturing hollow steel body |
-
2001
- 2001-03-21 JP JP2001080073A patent/JP3920581B2/en not_active Expired - Lifetime
-
2002
- 2002-03-13 WO PCT/JP2002/002349 patent/WO2002074462A1/en active IP Right Grant
- 2002-03-13 DE DE60208011T patent/DE60208011T2/en not_active Expired - Lifetime
- 2002-03-13 EP EP02705123A patent/EP1375019B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP1375019A1 (en) | 2004-01-02 |
| DE60208011D1 (en) | 2006-01-19 |
| JP2002273512A (en) | 2002-09-25 |
| WO2002074462A1 (en) | 2002-09-26 |
| EP1375019A4 (en) | 2004-06-02 |
| JP3920581B2 (en) | 2007-05-30 |
| DE60208011T2 (en) | 2006-07-13 |
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