METHOD OF GUIDING MATERIAL TO FIN-PASS ROLL AND ITS GUIDE ROLL STAND

Abstract: A pair of slit type horizontal fin rolls (18) and a pair of vertical side rolls (19) having such a shape as having the conventional vertical side roll (19) formed by contracting its center portion are utilized, and due to the construction in which one set of each horizontal fin roll (18) and vertical side roll (19) is adjustable horizontally, the depressing force is not applied to the material, and since the edge is restrained and shifted widthwise only with the horizontal force of the vertical side rolls (19) rotating freely, threading can be conducted very smoothly irrespective of the sectional shape of the material after break down, and even if the material size is changed, the threading can be conducted very smoothly without adjusting the roll position as strictly as in the past.

Description: DE SCRIPT CON TITLE OF THE INVENTION Method of Guiding Material to Fin-pass Roll and Its Guide Roll Stand TECHNICAL FIELD The present invention relates to a method of guiding a material to a fin-pass roll and a guide roll stand for fin- pass which is suitable for producing the thin pipes and the like and whereby, in a pipe mill for producing pipes such as a seam welded steel pipe, gripping of the material at threading can be conducted very smoothly, preventing the edge stretch and scratch, and having a high correcting effect for the necessary circular shape. BACKGROUND ART In general, when producing pipes in a pipe mill, a band material is first formed from its edge portion and into a semicircular shape with break down rolls, then its center portion is formed with cluster rolls and fed to squeeze rolls after adjusting the edge angle and finishing and centering with fin-pass rolls. Also, in the cage forming, similarly, necessary down, and then moved to the fin-pass in a reducing forming region. In both cases, the last forming and correction are conducted in a group of fin-pass roll stands in preparation for welding. Since the formability here is decisive of the quality of the final product, consideration is given to prevent such strains as so-called the edge stretch and edge buckling and roll marks, and various types of fin-pass rolls as well as fin-pass roll stands are proposed. On the other hand, the material which has been formed in the break down roll or the cage roll, proceeds in the state wider than at forming due to the spring back, and since a horizontal movement of the edge is larger, gripping guidance or threading to the fin-pass roll may be not conducted smoothly requiring mpre time for the material end to be gripped by the fin÷pass rolls. Also, when the material is fed into the fin-pass rolls, forming is effected by halved or quartered rolls, but since the forming sectional shape of the material before the fin- pass rolls is not in a necessary shape due to the insufficient forming, the material was susceptive to the contact flaw caused by the difference in circumferential velocity arising from the difference between the center and end diameters of the roll. In the past, in order to avoid the slip flaw, a pipe mill provided with a edge guide roll stand, in which a pair of vertical rolls and edge guide rolls with V-shaped section are arranged, disposed in the front stage of the fin-pass roll stand has been proposed in Japanese Patent No. 53447/81. Also, in cage roll forming, a method of producing seam welded steel pipes whereby the edge portion is restrained for forming with the V roll in the front stage side of the fin- pass, improving the formability and eliminating the gap between the cage roll and fin-pass roll, has been proposed in Japanese Patent Provisional Publication No. 166321/84. Prior arts aforementioned are both efficacious for correcting insufficient forming of the forming sectional shape of the material before passing into the fin-pass roll, but for example, at threading of the material end,- as shown in Fig. 6, since the horizontal V roll (30) rotates as restraining the material edge (21) and a large angle presents between the tangential direction (F) of the frictional force, and the moving direction (S) of the material (20), component (D) of the frictional force is produced to act as depressing the edge portion (21) and so-called shifting it widthwise horizontally, thus slipping takes place on the roll face, producing the edge wave and edge stretch, in particular, in case of the thin steel pipes. Also, in order to facilitate the threading, the V roll must be shaped deeper. However, if the V roll is formed deeper, the material is susceptive to roll mark so the roll diameter must be reduced or a plurality of V rolls must be used, resulting in difficulty of adjusting the roll position and eventually of avoiding the edge stretch, scratch and so on. Taking into account to such a situation in the pipe mill, it is an object of the present invention to provide a method of guiding a material to fin-pass rolls and a guide roll stand for the fin-pass, which largely facilitates gripping of the material at threading, preventing the edge stretch and scratch, having a high correcting effect to the desired circular shape and is suitable for producing the thin steel pipes and the like. DISCLOSURE OF THE INVENTION The present invention is a method of guiding a material to fin-pass rolls characterized by threading the material as supporting its edge face in contact with a -pair of flat horizontal rolls arranged opposingly at a necessary distance on the upstream side of the fin-pass rolls in a pipe mill, supporting adjacent the both edge portions of the material in contact with a pair of vertical rolls arranged normally to the each horizontal roll shaft, and supporting the center portion of the material in contact with a horizontal roll for threading. The present invention is also a guide roll stand for the fin-pass characterized by comprising the roll stand dispose d on the upstream side of the fin-pass rolls in the pipe mill, and a frame of which height is adjustable in the vertical direction of said roll stand, mounting in the frame a face plate which is freely engageable and a horizontal roll whose height is adjustable toward the frame center and disposed on the bottom of the face plate to support the center of the material, mounting a support frame freely adjustably horizontally on each inner side of both sides Of the face. plate, and mounting horizontally arranged fin rolls for supporting the material edge in contact, and vertical side rolls having shafts normally to the fin roll shafts for supporting adjacent the material edge in contact. In the present invention, a pair of split type horizontal fin rolls and a pair of vertical side rolls having such a shape as having the conventional vertical side roll formed by contracting its center portion are utilized, and since a depressing force to the material is not applied due to the construction in which each horizontal fin roll and vertical side roll is adjustable horizontally in one set, and the edge is restrained and shifted widthwise only with a horizontal force of the freely rotating vertical side rolls, there is such an advantage as that threading is conducted very easily irrespective of the sectional shape of the material after break down, and even the material size is changed, it may be conducted very easily without adjusting the roll position as strictly as in the past. In detail, in the present invention, as shown in Fig. 4, the horizontal fin rolls (18) (18) contact the edge face of the material (20) and the vertical side roll rolls (19) (19) on the vertical shafts contacts its edge portion (21) for rotation, due to the structure where one set of each horizontal fin roll (18) and vertical side roll (19) is arranged on the orthogonal shafts to rotate freely respectively, but since the tangential direction (F) of the frictional force and the moving direction (S) of the material (20) is generally the same, component (D) of the frictional force is hardly produced and the edge portion (21) is not _. influenced by the depressing force, rendering such construction as shifting widthwise only with the horizontal force of the freely rotating vertical side rols, so that occurrence of edge waves and edge stretches which apt to occur as using the conventional V type roll or in the production of the thin steel pipes, as well as the prior art problem of scratches produced on the material may be prevented. Also, as shown in Fig. 5, even if the sectional shape of the material (20) after break down is highly oval, the intermediate portions of the material (20) may be expanded and formed into a necessary circular shape by a necessary biasing force of the bottom roll (11), thus the amount of contraction in .the fin-pass rolls may be reduced. Also, since one set of each horizontal fin-roll and vertical side roll is adjustable horizontally, and the position where the material edge contacts the roll surface of the vertical side rolls is adjustable due to the structure in which the entire face plate can be moved vertically, even when the material size is changed to some extent rolls may be used commonly. Furthermore, in the guide roll stand for fin-pass in accordance with the present invention, each roll can be adjusted very easily and freely, thus by preparing a plurality of face plates mounted with rolls for various diameters in advance and exchanging the same, the productivity of various types of pipes by small quantities can be largely improved. In the present invention, a pair of split type horizontal fin rolls may be of a non-driven or driven type. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front view illustrating a face plate and a frame mounted with guide rolls according to the present invention. Fig. 2 and Fig. 3 are front and plan views illustrating a guide roll stand for fin-pass according to the present invention. Figs. 4a, b, c and Fig. 5 are illustrative views showing the relationship between a guide roll according to the present invention and a material edge portion. Figs. 6a, b are illustrative views showing the relationship between a conventional horizontal V roll and a material edge portion. BEST MODE FOR CARRYING OUT THE INVENTION Fig. 1 is a front view illustrating a face plate and a frame mounted with guide rolls according to the present invention. Fig. 2 is a front view illustrating a guide roll stand for fin-pass according to the present invention. The guide roll stand (1) comprises a pair of leg portions (2) (2) and a base portion (3) connecting thereof, and opposite sides of a frame (7) having a rectangular sectional shape and incorporating a face plate (10) to which rolls are mounted for free engagement are inserted freely engageable vertically between the leg portions (2) (2). Also, on the base (3), a pair of screw jacks (4) (4) for supporting and biassing both bottom ends of the frame (7) inserted for free vertical movement between the leg portions (2) (2) to adjust its height vertically are disposed. In addition, a connecting shaft (6) is provided between the pair of screw jacks (4) (4), since they are driven by an oil hydraulic motor (5) via a worn gear. The frame (7) is constructed by assembling a main body (7a) and steel materials such as plate members (8) (9), square bars and the like, and on the opposed surfaces of the main body (7a) on the sides of leg portions (2) (2), grooves are provided to accommodate the face plate (10) for mounting the rolls in the frame (7) for free engagement vertically. In the face plate (10), a center opening (10a) through which the material is inserted is opened, and around which various rolls are disposed. That is, on the center of the bottom side of the face plate (10), a horizontal receiving roll (11) for supporting the center portion of the material is supported by a supporting frame (12), which is engaged to slide frames (13) arranged vertically so that its height is adjustable toward the center of the frame (7) with a screw jack (14) secured thereto. Also, on the inner opposite sides of the face plate (10), slide frames (15) (15) are arranged at the upper and center portions respectively at a necessary interval, between each slide frames (15) (15), roll supporting frames (16) (16) are disposed respectively in a horizontal direction slidably, and each roll supporting frame (16) is adjustable horizontally with screw jacks (17) (17) secured to the outer opposite sides of the frame (7). On the opposed sides of the supporting frames (16) (16), fin rolls (18) .(18) for supporting the material edge face in contact are arranged horizontally, and in addition, vertical side rolls (19) (19) for supporting adjacent the material edge portion in contact are mounted on the supporting shafts arranged orthogonally underneath, the fin roll shafts (18) (18). That is, the face plate (10) disposed for free engagement on the frame (7) of the guide roll stand (1) is mounted with respective rolls of the horizontal receiving roll (11), fin rolls (18) (18) and vertical side rolls (19) (19), and is finely adjustable within a certain range corresponding to the size and shape of the material passing through the center opening (10a) of the face plate (10). Also, a plurality of face plates (10) mounted with the rolls for various diameters in advance may be prepared. The guide roll stand (1) constructed as described above is arranged between the break down roll or cage roll and the fin-pass roll. When the material end is fed into the guide roll stand (1) after completing the break down, even if its sectional shape is highly oval and its edge portion is widen, due to the vertical rolls (19) (19) consisting of the upper half of the conventional vertical roll which is formed by contracting the center portion and rotating freely, the material edge can be restrained without accompanying almost any downward pressing force, thus the threading is conducted smoothly and edge waves are eliminated. Also, as shown in Fig. 5, the material is apprehended by the fin rolls (18) (18) at its edges (21) (21) and its center portion is biased by the horizontal receiving roll (11) so as to be expansible into a circular shape, thus the material formed into a present sectional shape may be fed to the following fin-pass rolls. INDUSTRIAL APPLICABILITY That is to say, in the guide roll stand (1) of the present invention, since the depressing force is not applied to the material due to the split type horizontal fin rolls (18) (18) and vertical sluster rolls (19) (19) which are mounted integrally on the support frame and adjustable horizontally, threading of the material can be conducted very smoothly irrespective of its sectional shape after the break down, thus edge waves and edge stretches can be prevented and moreover, even if the sectional shape is highly oval, due to the necessary biasing force of the horizontal receiving roll (11), the intermediate portion of the material can be expanded and formed into a circular shape, efficacious in reducing the amount of contraction in the following fin-pass rolls.

Claims: CLAIMS 1. A method of guiding a material to a fin-pass roll characterized in that, edge face of the material are supported in contact with a pair of flat horizontal rolls arranged opposingly at a necessary interval on the upstream side of the fin-pass roll in a pipe mill, the material is supported in contact adjacent its edge portions with a pair of vertical rolls arranged orthogonally to said each horizontal roll, and the material is supported in contact at its center portion with a horizontal roll for threading. 2. A guide roll stand for fin-pass characterized by comprising a roll stand arranged on the upstream side of a fin-pass roll in a pipe mill, and a frame of which height is adjustable in the vertical direction of said roll stand, mounting a freely engageable face plate and a horizontal roll whose height is adjustable toward the frame center and disposed on the bottom of the face plate for supporting the center portion of the material in contact in the frame, mounting a support frame which is freely adjustable horizontally on each inner opposite sides of the face plate, and, mounting horizontal fin rolls for supporting the edge face of the material in contact and vertical side rolls for supporting adjacent the material edge in contact and having shafts orthogonal to the fin roll shafts.

Inventors: KURAMOTO RYOSUKE, KURAMOTO, RYOSUKE
Applicants: NAKATA MFG, NAKATA MANUFACTUR COMPANY LIMITED
Application year: 1987
Main classification: B21D5
IPC codes: B21C37, B21D5