GB2025289A - Method of and Apparatus for Rolling Tubes - Google Patents

Method of and Apparatus for Rolling Tubes Download PDF

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Publication number
GB2025289A
GB2025289A GB7920272A GB7920272A GB2025289A GB 2025289 A GB2025289 A GB 2025289A GB 7920272 A GB7920272 A GB 7920272A GB 7920272 A GB7920272 A GB 7920272A GB 2025289 A GB2025289 A GB 2025289A
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GB
United Kingdom
Prior art keywords
metal block
bushing
diameter
rolled
rolls
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.)
Granted
Application number
GB7920272A
Other versions
GB2025289B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
KM Kabelmetal AG
Original Assignee
KM Kabelmetal AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by KM Kabelmetal AG filed Critical KM Kabelmetal AG
Publication of GB2025289A publication Critical patent/GB2025289A/en
Application granted granted Critical
Publication of GB2025289B publication Critical patent/GB2025289B/en
Expired legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21BROLLING OF METAL
    • B21B19/00Tube-rolling by rollers arranged outside the work and having their axes not perpendicular to the axis of the work
    • B21B19/02Tube-rolling by rollers arranged outside the work and having their axes not perpendicular to the axis of the work the axes of the rollers being arranged essentially diagonally to the axis of the work, e.g. "cross" tube-rolling ; Diescher mills, Stiefel disc piercers or Stiefel rotary piercers
    • B21B19/04Rolling basic material of solid, i.e. non-hollow, structure; Piercing, e.g. rotary piercing mills
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21BROLLING OF METAL
    • B21B39/00Arrangements for moving, supporting, or positioning work, or controlling its movement, combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B39/14Guiding, positioning or aligning work
    • B21B39/16Guiding, positioning or aligning work immediately before entering or after leaving the pass

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Forging (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Laminated Bodies (AREA)
  • Metal Rolling (AREA)
  • Rolls And Other Rotary Bodies (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)

Abstract

In the rolling of tubes from cylindrical and preferably heated metal blanks by piercing the blank with a mandrel and then rolling it between inclined rolls, the blank is fed to the rolls through at least one bushing (4) having a diameter only slightly greater than that of the block and mounted in a housing (1, 2, 3) by means of axially-spaced ball-bearings (5, 6) for free or driven rotation. Since the blank is rotated by the inclined rolls, the use of a rotatable bushing (4) avoids the production of surface faults by friction with the inner wall of the inlet channel. Preferably a plurality of bushings spaced apart in series is used to support the full length of the blank. <IMAGE>

Description

SPECIFICATION Method of and Apparatus for Rolling Tubes The present invention relates to a method of and apparatus for rolling tubes from a cylindrical and preferably heated metal block, in which the metal block is pierced by a stationary mandrel and is drawn by passage between a plurality of inclined driven rolls.
Hot inclined rolling mills of the type referred to above have long been known and, when used for tube manufacture, enable the production of tubes having a uniform wall thickness to be carried out in an economical fashion. A heated metal block is normally fed to the inclined rolls through an inlet channel. The transport of the metal block is effected by a ram which pushes the metal block into the gap between the rolls and against the stationary mandrel. At this instunt, the rolls contact the metal block to which they impart components of movement both in the longitudinal axial direction of the block and in the peripheral direction. Since the rolls are inclined, the component of movement in the peripheral direction considerably exceeds that in the longitudinal axial direction.When the metal block rotates, friction between the metal block and the inlet channel produces serious faults at the surface of the metal block which make it virtually impossible to further process the rolled tube in subsequent drawing operations.
It is accordingly an object of the present invention to provide an improvement in the known method and apparatus such that surface faults on the rolled tube are either eliminated or at least greatly reduced.
According to one aspect of the invention, there is provided a method of rolling a tube from a cylindrical and preferably heated metal block, in which the metal block is pierced by a stationary mandrel and is drawn on said mandrel by passage through a plurality of inclined driven rolls, wherein prior to its passage between said rolls, the metal block is carried by at least one bushing which is mounted for free or driven rotation, and whose inner diameter only slightly exceeds the outer diameter of said metal block to be rolled.
According to another aspect of the invention, there is provided apparatus for carrying out such a method comprising q plurality of inclined driven rolls, through which a cylindrical metal block from which a tube is to be rolled is adapted to be passed, and at least one bushing located upstream of said driven rolls in the direction of movement of a block to be rolled and through which said block is passed in use, the or each said bushing being arranged for free or driven rotation and having an inner diameter which only slightly exceeds the diameter of the metal block to be rolled.
With the method and apparatus of the invention, an additional advantage is obtained in that, owing to the reduction in friction, the energy requirement for the rolls is reduced. Moreover, twisting of the metal block which could otherwise occur in particular in the case of long metal blocks, is virtually eliminated. Since the bushing is mounted so as to be freely rotatable, the surface of the metal block which, particularly when it is heated, is very liable to damage, no longer develops surface faults. If the bushing is driven the rotational speed of the bushing should correspond approximately to the speed of rotation of the metal block produced by passage through the rolls.
It has been found to be advantageous for the metal block to be carried over its entire length by a plurality of bushings whose axial length corresponds to twice to four times the diameter of the metal block and whose axial spacing from one another is less than the diameter of the metal block. Such a dimensioning ensures a satisfactory guidance of the metal block and prevents the metal block from sagging between two adjacent bushings. The distance between the bushings should at least be so selected that a highpressure jet of water can be sprayed onto the metal block.
This removes oxides from the surface of the metal block and also forms a cushion of water vapour between the metal block and the inner surface of the bushing. The bushing itself can be mounted in a housing by means of two ball-bearings spaced axially from one another. Together with the housing, the bushing forms an annular chamber between the bali-bearings which can be supplied with a cooling medium through openings provided in the housing. Water may, for example, be used as the cooling medium. The cooling of the bushing prevents the solidity of the material of the bushing being affected by contact with the red hot metal block. The cooling of the bushing can be further improved if the outer surface of the bushing is provided in the region of the annular chamber, with a plurality of projections which serve to increase the surface area.The cooling of the bushing is also advantageous in that it prevents excessive heating of the ball-bearings.
For this reason, the bushing should preferably be produced from a material which has a relatively good thermal conductivity. In order to prevent the cooling water from penetrating into the ball bearings, the annular chamber is sealed off from the ball-bearings.
The invention will now be further described with reference to the drawing, which is a schematic side-sectional view of a bushing and its mounting for use in the apparatus of the invention.
Referring to the drawing, a bushing 4 is mounted by means of ball-bearings 5 and 6 so as to be freely rotatable in a housing which comprises a tubular component 1 and two end components 2 and 3. The tubular component 1 is provided with apertures 7 and 8 which serve for the supply and discharge of cooling water respectively. The cooling water serves to remove the heat which is supplied to the bushing 4 from a red-hot metal block which is carried through the interior of the bushing 4. In order to further increase the cooling of the bushing 4, its inner surface is provided with a plurality of projections 9 which enlarge the surface area of the bushing 4 in the region of an annular chamber 10 formed between the tubular component 1 and the bushing 4.In order to prevent cooling water from penetrating into the ball-bearings 5 and 6, sealing lips 11 and 12 respectively are provided between the chamber 10 and the ball-bearings which consist of an abrasion-resistant synthetic resinous material.
A suitable material for the bushing 4 is one having a high wear resistance when hot and a relatively high thermal conductivity. Good results have been achieved using bronze and also tool steel.
Particularly when the metal blocks to be rolled are long, it has been found to be expedient to arrange a plurality of bushings such as that shown in the drawing in series. Such an arrangement is not, however, illustrated. In such an arrangement, the interval between the bushings should not be too great in order to prevent the metal block from sagging. However, it should be possible to spray water onto the metal block in the intervals between the bushings. The length of the bushing is expediently twice to four times the diameter of the metal block.

Claims (9)

Claims
1. A method of rolling a tube from a cylindrical and preferably heated metal block, in which the metal block is pierced by a stationary mandrel and is drawn on said mandrel by passage through a plurality of inclined driven rolls, wherein prior to its passage between said rolls, the metal block is carried by at least one bushing which is mounted for free or driven rotation, and whose inner diameter only slightly exceeds the outer diameter of said metal block to be rolled.
2. A method as claimed in Claimed, wherein the metal block is carried over its entire length by a plurality of bushings whose axial length is two to four times the diameter of the metal block and whose axial spacing relative to one another is less than the diameter of the metal block.
3. Apparatus for carrying out a method as claimed in Claim 1, comprising a plurality of inclined driven rolls through which a cylindrical metal block from which a tube is to be rolled is adapted to be passed, and at least one bushing located upstream of said driven rolls in the direction of movement of a block to be rolled, and through which said block is passed in use, the or each said bushing being arranged for free or driven rotation and having an inner diameter which only slightly exceeds the diameter of the metal block to be rolled.
4. Apparatus as claimed in Claim 3, comprising an axially-arranged plurality of said bushings having an axial length which is two to four times the diameter of the metal block to be rolled and the axial spacing of which reiative to one another is less that the diameter of the metal block to be rolled.
5. Apparatus as claimed in Claim 3 or Claim 4, wherein the or each said bushing is mounted for rotation in a housing by means of two ballbearings which are spaced from one another in the axial direction of the bushing.
6. Apparatus as claimed in any one of Claims 3 to 5, wherein the or each said bushing, together with the housing between said ball-bearings, forms an annular chamber which is adapted to be supplied with a cooling medium through openings in said housing.
7. Apparatus as claimed in Claim 6, wherein the outer surface of the or each said bushing is provided, in the region of said annular chamber, with a plurality of projections which enlarge the area of said surface.
8. Apparatus as claimed in Claim 6 or Claim 7, wherein said annular chamber is sealed from said ball-bearings.
9. Apparatus for rolling a tube from a cylindrical metal block substantially as hereinbefore described with reference to the drawing.
GB7920272A 1978-06-15 1979-06-11 Method of and apparatus for rolling tubes Expired GB2025289B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19782826217 DE2826217A1 (en) 1978-06-15 1978-06-15 DEVICE FOR ROLLING PIPES

Publications (2)

Publication Number Publication Date
GB2025289A true GB2025289A (en) 1980-01-23
GB2025289B GB2025289B (en) 1982-04-28

Family

ID=6041851

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7920272A Expired GB2025289B (en) 1978-06-15 1979-06-11 Method of and apparatus for rolling tubes

Country Status (7)

Country Link
BE (1) BE876971A (en)
DE (1) DE2826217A1 (en)
ES (1) ES481524A1 (en)
FR (1) FR2428481A1 (en)
GB (1) GB2025289B (en)
IT (1) IT1116566B (en)
SE (1) SE7905226L (en)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US999757A (en) * 1906-06-20 1911-08-08 Samuel E Diescher Piercing-mill and the like.
US3132545A (en) * 1960-05-20 1964-05-12 Vincenzo S Arata Cycloidal rolling mill
DE2505769A1 (en) * 1975-02-12 1976-08-26 Kabel Metallwerke Ghh PROCESS FOR MANUFACTURING SEAMLESS METALLIC PIPES

Also Published As

Publication number Publication date
DE2826217C2 (en) 1989-03-02
SE7905226L (en) 1979-12-16
GB2025289B (en) 1982-04-28
DE2826217A1 (en) 1979-12-20
BE876971A (en) 1979-10-01
FR2428481A1 (en) 1980-01-11
IT7948398A0 (en) 1979-03-19
ES481524A1 (en) 1980-01-16
IT1116566B (en) 1986-02-10

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Legal Events

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PCNP Patent ceased through non-payment of renewal fee