EP0345241B2 - Method for producing a laminated section comprising a corrugated part, and installation therefor - Google Patents

Abstract

To produce an I-section (1) rolled in one piece, of which part (9) of the web (3) is corrugated, the section is passed between two rolls having an increased diameter over a portion of length, and it is subsequently passed between two rollers having a structured surface, so as to carry out a continuous uniform folding.

Description

The present invention relates to a process for the manufacture of laminated sections such as a U or a beam, more particularly an I-beam, comprising a corrugated part in particular a wing or a core.

It also relates to a particular installation intended for this purpose.

From US-A-4 251 973, an I-beam is known having a corrugated core welded to the flanges. In addition, there is described a manufacturing process in which a flat core is welded to a pair of flanges and the beam thus formed passes between two cylinders stamping the soul of the beam in a desired manner.

A beam of the aforementioned type is however subjected to significant internal stresses. Indeed, the weld creates tensions in the beam which risk deforming it and / or warping the soles. In addition, the rolling of a part of the core implies an elongation of the latter with as a consequence a reduction in its thickness. This also results in high tensions on the welds between the core and the flanges and internal tensions in the core, given the differential deformations. These tensions also risk deforming the finished beam and / or warping it. In addition, these tensions can have an unfavorable influence on the behavior of the beam and in particular on its mechanical resistance to the various forces to which it may be subjected during its use. In addition, this process necessarily involves a weldable steel.

Document LU-A-83 044 (SUMITOMO METAL) discloses a method of manufacturing an I-beam, with a corrugated core in its middle, according to which corrugations are formed in a median part of the core of an ordinary I-beam finished by means of two cylinders which mesh in a complementary manner. In accordance with this method, the increase in the developed length of the corrugated core from the straight length of a flat core before formation of the corrugations is ensured by the reduction in the thickness of the core under the effect of the wave formation work.

From the description and the drawings, it follows that the I-beam with corrugated core is obtained from an ordinary finished beam and this by means of one or more rolling operations between two opposite structured cylinders. Indeed, the additional length is provided by the reduction of the thickness of the core thanks to the action of two structured cylinders, which obviously causes internal tensions and a significant hardening of the material and, therefore, a camber or a twist of the beam in 1. The holder of the aforementioned patent attempts to remedy this drawback by forming the corrugations in the core in two or more passes. However, the problem of internal tensions is not at all resolved and, moreover, the process is quite expensive.

The document FR-A-744 933 discloses metal sections with a locally reduced core section, obtained by simple rolling.

This document does not mention the manufacture of a laminated profile comprising a corrugated part. In addition, the passage of a profile of the type described in the process steps of patent LU-A-83 044 (SUMITOMO) would lead to the production of a product whose section of the reduced part would be further thinned by rolling, which would lead to the same drawbacks as those mentioned above.

GB-A-1,596,636 describes a method and an apparatus for profiling a sheet of material and preferably a thin metal sheet. The method consists first of all in causing an elongation of the central part so as to form an indefinite undulation.

The second stage of the process consists in subjecting the sheet obtained in the first stage to deformation rolls (embossing rolls) in order to produce a deep design.

From the figures, it is observed that there is an almost total gear of the 2 cylinders in order to create the desired deformation.

According to a first aspect of the present invention, the latter seeks to provide a simple method for the manufacture of a profile of the above-mentioned type, and of a cost practically equivalent to that of a normal beam.

Another object of the present invention is to provide a method of manufacturing a profile of the aforementioned type which does not have the drawbacks of the methods known in the prior art and which allows, more particularly, the easy manufacture of laminated profiles comprising a corrugated part which presents a minimum of residual tensions and internal stresses.

According to another aspect, the invention aims to provide an installation of a new type for the manufacture of said profiles.

• on procède d'abord au laminage classique de manière connue en soi jusqu'à obtention d'une ébauche proche de la finition;
• on provoque une surlongueur locale de l'ébauche ainsi obtenue correspondant à la partie ondulée, en la faisant passer entre deux cylindres dont l'un au moins présente un diamètre plus élevé sur une portion de sa longueur;
• on procède à une mise en forme par une opération de pliage régulier et répété des ondulations obtenues à l'étape précédente, cette mise en forme par pliage étant effectuée entre deux galets qui sont situés dans un plan essentiellement perpendiculaire au sens de défilement du profilé et qui comportent une surface structurée, à savoir des galets à surface rainurée ou cannelée, formant des dents dans le sens axial sur une longueur correspondant essentiellement à la partie de plus grand diamètre du galet ou cylindre de la deuxième étape et, de ce fait, à la portion de hauteur de la partie de profilé qui est ondulée, les deux galets opposés structurés ne s'engrènant que partiellement, de manière que la partie ondulée du profilé laminé entre en contact uniquement avec les sommets successifs desdites dents de chaque galet.

In accordance with the present invention, the laminated sections comprising a corrugated part in the longitudinal direction of the section, over a portion of its height, are obtained by the manufacturing process comprising the following operating steps:

• conventional rolling is first carried out in a manner known per se until a blank close to the finish is obtained;
• causing a local excess length of the blank thus obtained corresponding to the corrugated part, by passing it between two cylinders, at least one of which has a larger diameter over a portion of its length;
• a shaping is carried out by a regular and repeated folding operation of the undulations obtained in the previous step, this shaping by folding being carried out between two rollers which are situated in a plane essentially perpendicular to the direction of travel of the profile and which have a structured surface, namely rollers with grooved or grooved surface, forming teeth in the axial direction over a length essentially corresponding to the part of larger diameter of the roller or cylinder of the second step and, therefore, to the height portion of the profile part which is corrugated, the two opposite structured rollers meshing only partially, so that the corrugated part of the laminated profile comes into contact only with the successive vertices of said teeth of each roller.

The laminated profile treated in accordance with the present invention is particularly resistant in particular to bending and buckling. As a result, for a desired mechanical strength, the weight of said profile can be reduced. Furthermore, given the simplicity of the process and the various steps used, the price of the profile obtained is lower than that of other known types.

In addition, the method of the invention makes it possible to obtain a profile, a part of which has an undulation without the individual stresses or the internal tensions being significant. Indeed, during the passage of the blank obtained in the first step of the process between two cylinders or rollers, one of which at less has a larger diameter over part of its length, the space between the two cylinders or rollers is therefore reduced locally The local rolling of the core thus obtained, over a distance less than its height between the flanges, prevents the creep of said soles. In addition, unwanted wing deformations are avoided. The larger diameters of the rolling rolls over a height portion of a section portion, in particular over a portion of the core of an I-beam, and consequently the reduction in the gap between said rolls, creates tensions which tend to elongate the corresponding portion of the profile part and cause an undulation of said portion. In a third step, these corrugations are shaped by simple folding. Indeed, the undulations obtained in the second step do not have the desired regularity, this is obtained by folding which also essentially eliminates the internal stresses induced in the previous phase.

Unlike the process of the invention, the process known from document LU-A-83 044 practices continuous rolling in a single step of the core of a finished laminated section. This of course results in significant work hardening constraints.

Advantageously, the percentage of additional elongation to be given to the portion of the profile part to be corrugated is substantially equal to the percentage of excess length of the corrugation desired relative to the straight line. In this way, it is guaranteed that the subsequent folding operation introduces the least possible work hardening constraints and that the folding operation is not associated with stamping.

According to a preferred embodiment of the invention, the shaping is carried out by folding between two rollers which are located in a plane essentially perpendicular to the direction of travel of the profile and which have a structured surface, in particular rollers with grooved surface or grooved in the axial direction over a length essentially corresponding to the portion of the largest diameter of the roller or cylinder of the second step and, therefore, to the height portion of the section portion which is corrugated.

In order to avoid as much as possible the work hardening of the material and in order to carry out a folding operation and not a stamping operation, the opposed structured rollers or rollers only mesh partially so that the rolled product is folded like a beam on two supports supporting a point load in the middle of its span.

The profiles according to the present invention are particularly suitable in applications requiring high strength and low weight.

In particular in the case of an I-rolled section, the local rolling of the core over a distance less than its height between the two flanges prevents the creep of said flanges. In addition, unwanted wing deformations are also avoided.

We can for example cite the construction of rigid chassis of vehicles, in particular trucks or public transport vehicles.

Advantageously, the shaping step is carried out by folding in a straightening machine which, moreover, makes it possible to straighten the profile obtained in a conventional manner.

• une installation classique de laminage connue en soi pour le laminage jusqu'à obtention d'une ébauche proche de la finition;
• une cage de laminage comportant deux cylindres (21,23) qui sont disposés dans un plan essentiellement perpendiculaire au plan de défilement de la partie (3) de profilé (1) à onduler et dont l'un au moins présente un diamètre plus élevé sur une portion de sa longueur (9), ladite cage comportant encore des cylindres verticaux (28,29) de laminage dudit profilé qui en imposent les dimensions extérieures;
• un dispositif de mise en forme par pliage régulier et répété en continu, comportant essentiellement deux cylindres ou galets (41,43) qui sont situés dans un plan essentiellement perpendiculaire au sens de défilement du profilé et qui comportent une surface structurée, de préférence rainurée ou cannelée, formant des dents dans le sens axial sur une longueur axiale correspondant essentiellement à la portion de hauteur de la partie ondulée du profilé à fabriquer, les galets ou cylindres structurés opposés (41,43) ne s'engrènant que partiellement l'un dans l'autre, de manière que la partie ondulée du profilé laminé entre en contact uniquement avec les sommets successifs desdites dents de chaque galet.

According to another aspect of the present invention, the installation intended for the manufacture of a profile of the aforementioned type comprises at least:

• a conventional rolling installation known per se for rolling until a blank close to the finish is obtained;
• a rolling stand comprising two rolls (21,23) which are arranged in a plane essentially perpendicular to the running plane of the section (3) of profile (1) to be corrugated and at least one of which has a larger diameter on a portion of its length (9), said cage also comprising vertical rolls (28,29) for rolling said profile which impose its external dimensions;
• a device for shaping by regular folding and repeated continuously, essentially comprising two cylinders or rollers (41, 43) which are situated in a plane essentially perpendicular to the direction of travel of the profile and which comprise a structured surface, preferably grooved or grooved, forming teeth in the axial direction over an axial length essentially corresponding to the height portion of the corrugated part of the profile to be manufactured, the opposite structured rollers or rollers (41,43) only partially engaging one in the other, so that the corrugated part of the laminated section comes into contact only with the successive vertices of said teeth of each roller.

• la figure 1 est une vue en coupe à travers un profilé laminé en I dont l'âme est ondulée sur une partie de sa hauteur;
• la figure 2 est une vue schématique de laminage localisé du profilé laminé;
• la figure 3 est une vue schématique de l'opération de pliage; et
• la figure 4 est une vue schématique de la dresseuse utilisée dans l'installation conforme à la présente invention.

The invention is described in more detail below in support of an exemplary embodiment supported by the drawings in which:

• Figure 1 is a sectional view through a laminated I-shaped section whose core is corrugated over part of its height;
• Figure 2 is a schematic view of localized rolling of the rolled section;
• Figure 3 is a schematic view of the folding operation; and
• Figure 4 is a schematic view of the straightener used in the installation according to the present invention.

In the figures, identical reference marks represent identical or analogous elements.

In order to illustrate the present invention, the latter is described for a rolled I-shaped profile with a corrugated core. In FIG. 1, an I-section 1 is shown comprising a core 3 and two flanges 5 and 7, laminated in one piece with the core 3.

The core 3 has, on a portion 9 of its height, a corrugation II in the longitudinal direction of the I-shaped.

With a view to the manufacture of an I-shaped section in accordance with the invention, said section 1 is passed between two cylinders 21 and 23 arranged in a plane essentially perpendicular to the plane of the core 3 and forming part of a cage. rolling 20. The diameter of each of the two cylinders 21 and 23 is larger on a portion 9 than at the ends 25 and 27. The profile 1 is further further laminated by vertical cylinders 28 and 29 which maintain the external dimensions of the profile 1.

By passing a rolled profile 1 to a stage close to finishing in this cage, the overall dimensions of the profile must be maintained. The local shrinkage of the core causes an excess of material while preventing creep of the soles. This excess material creates tensions and an undulation of the portion 9 of the core distributed locally over the core 11.

The profile thus obtained can then pass through a straightener 31 for example equipped with straightening rollers 33 to 38 arranged in a manner known per se to make the laminated profile straight.

According to the present invention, said dressing cage comprises two rollers 41 and 43 which are arranged in a plane 39 essentially perpendicular to the running plane of the profile 1 and which have a surface grooved in the axial direction, one adapting to the another in the manner of a gear, only partially entangling so as to produce a folding (FIG. 3).

At this stage, the extra length previously created between the cylinders 21 and 23 is used to form the desired ripple and somehow neutralize the tensions previously created.

This gives a laminated profile in one piece in I with corrugated core which has very good mechanical properties and little internal tension. The hardening stresses are particularly reduced; as can be seen in Figure 3 where the folding involves curved sections 45 and even linear sections 47 essentially without constraint.

Note also that one of the two rollers can be rotated while the other is free to rotate.

Claims (6)

1. A process for producing a rolled section comprising a corrugated part in the longitudinal direction of the section, over a portion of the height thereof, comprising the working steps consisting in :

   - carrying out first a conventional rolling step in a way known per se until a blank close to finishing is obtained;

   - forming a local overlength of the so-obtained blank, corresponding to the corrugated part, by having it passed between two rolls, at least one of which has a larger diameter over a portion of the length thereof;

   - carrying out a shaping step by folding reegularly and repetitively the corrugations obtained in the preceding step, said shaping step being carried out by folding between two rollers which are located in a plane essentially perpendicular to the running direction of the section and which have a structured surface, namely rollers with a grooved or splined surface, forming teeth in the axial direction over a length corresponding essentially to the larger diameter part of the roller or roll of the second step and hence to the height part of the section part being corrugated, the two facing structured rollers intermeshing only partially so that the corrugated part of the rolled section only comes into contact with the successive tips of said teeth of each roller.
2. Process according to claim 1, characterized in that one carries out the step of shaping by folding at the same time as a straightening.
3. Process according to any of claims 1 and 2, characterized in that one causes the over length in such a way to give to the portion of the corrugated part of the section a percentage of elongation which is substantially equal to the percentage of over length of the desired corrugation in relation to the straight line.
4. Assembly for implementing a process for producing a rolled section according to any one of claims 1 to 3, comprising :

   - a conventional rolling equipment known per se for rolling until a blank close to finishing is obtained;

   - a stand mill comprising two rolls (21, 23) which are located in a plane essentially perpendicular to the running direction of the part (3) of the section (1) to be corrugated and one of which at least has a larger diameter over a portion of the length (9) thereof, said stand mill further comprising vertical rolls (28, 29) for rolling said section which set the external dimensions thereof;

   - a shaping device by regular repetitive continuous folding, comprising essentially two rolls or rollers (41, 43) which are located in a plane essentially direction of the running direction of the section and which have a structured surface, preferably grooved or splined, forming teeth in the axial direction over an axial length corresponding essentially to the height portion of the section corrugated part to be produced, the facing structured rollers or rolls (41, 43) intermeshing only partially so that the corrugated part of the rolled section only comes in contact with the successive tips of said teeth of each roller.
5. The installation as claimed in claim 4, characterized in that the device for shaping by folding is arranged in a straightener.
6. The installation as claimed in any one of claims 4 and 5, characterized in that one of the two grooved rollers is driven in rotation, the other rotating freely.

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