WO2002062499A1

WO2002062499A1 - Method for producing profiles by non-cutting shaping

Info

Publication number: WO2002062499A1
Application number: PCT/AT2002/000044
Authority: WO
Inventors: Dieter SCHUÖCKER
Original assignee: Schuoecker Dieter
Priority date: 2001-02-07
Filing date: 2002-02-07
Publication date: 2002-08-15
Also published as: ATA1912001A; DE10290355D2; AT410906B

Abstract

The invention relates to a method for producing profiles by non-cutting shaping of material in a shaping station, particularly a rolling station, through which the material is guided. According to the invention, thermal energy is supplied to the material, particularly in front of the shaping station. Said thermal energy is bundled e.g. as a laser beam.

Description

Process for the production of profiles by non-cutting shaping

The invention relates to a method for producing profiles by non-cutting shaping of material in a shaping station, in particular a rolling station, through which the material is moved, thermal energy being supplied to the material, in particular directly in front of the shaping station.

Metallic profiles of any length can be produced by non-cutting deformation using profile rollers. The rolling stock passes through several rolling mills one after the other, the axial cross sections of the two rolls belonging together corresponding to one stand, the top and bottom of the cross-section part of the profile produced by the stand, that is to say approximately wedge-shaped or V-shaped. By sequencing several such pairs of rollers, complex profiles can be produced using several forming steps. If the cross-section of the desired profile has small radii of curvature or edges that are too sharp, the fibers of the rolling stock lying on the outside with respect to the centers of the curvature have very large stretches, which under certain circumstances can exceed the elongation at break, which means that the profile cracks at such points after roll profiling has and thus becomes unusable. The problem is exacerbated when less ductile materials such as certain aluminum alloys, titanium or high-strength steels are rolled. Until now, roll forming, which is inexpensive due to its endless character, has so far been restricted to ductile materials and cross-sectional geometries with not too high degrees of deformation.

A method and a device for heating electrically conductive material have already become known, the material being moved through at least one processing station and being heated by an electrical current flowing between two associated contact elements via the electrically conductive material (DE-Al 41 26 175). In order to heat the electrically conductive material quickly, with a small footprint and with high efficiency by means of direct power transmission, the electric current flows between two neighboring ones Contact elements transverse to a material conveying direction through the material. The contact elements can also be designed as profile rollers. A disadvantage of such a method is the restriction to electrically conductive material and the fact that a large surface area of the material to be deformed is heated. A high energy supply is therefore required to achieve the required heating locally. In addition, the heat supply in places where this is not absolutely necessary in order to avoid material cracks is not absolutely desirable.

Furthermore, conductive heating of the material to be deformed has also become known (EP 314 667). Use is made of two pairs of contact rollers which are slidably mounted along the material to be heated. In the conveying direction of the goods, there is a direct current passage from one pair of contact rollers over the goods to the other pair. A disadvantage of this method is that the space required is large because of the contact roller pairs which are spaced apart from one another. In addition, there is a committee during the start-up of the plant, which is approximately 1.5 times the length of the plant.

The invention is based on the object of eliminating or at least reducing the restrictions to which the above-mentioned known methods are subject and to be able to extend the deformation, in particular by profile rolling, to materials which are less suitable for cold forming and expand to profiles with particularly high degrees of deformation. This is achieved in a method of the type mentioned at the outset if, according to the invention, the thermal energy is concentrated, e.g. as a laser beam. A bundled supply of energy is also possible by using a plasma beam or microwave beams.

The present invention takes advantage of the fact that generally the ductility of metals, and also of many other materials, such as thermoplastics and glass, is improved at elevated temperature, which is demonstrated by the fact that the yield stress required for the onset of plastic deformation decreases with increasing temperature, with steel at one Temperature increase by 500 ° by about 40%. Furthermore, the achievable strains increase with increasing temperature. Thus, by heating the rolling stock by bundling the energy shortly before the deformation during rolling, before the material to be deformed is gripped by the rollers at those points where profile cross-sectional areas with small radii of curvature have arisen after leaving the pair of rollers, heating with more or less focused laser beam an improved forming can be achieved so that the material does not break, which would otherwise be unavoidable in the cold state with the given material and the desired profile.

In a further embodiment of the invention, the heat is supplied in a bundled form, in particular by means of the laser beam, to those points of the material at which, following the heating, a sharp bend or an angle at an acute angle is produced in the deformation station. By means of the laser, which is supplied as a more or less highly focused high-power semi-laser, the material to be deformed is heated in the area of the focal spot, the size of which is selected so that it covers the area in which significant strains occur during the deformation following the heating , covered.

In a preferred embodiment of the method according to the invention it can be provided that (seen in the direction of movement of the material) an absorption-increasing coating, e.g., before the point of impact of the laser beam on the material to be deformed. made of graphite, applied to the material, in particular sprayed on. The covering largely prevents reflections of the laser beam. The point at which the absorption-increasing coating hits the material to be deformed during application can be located close to - approximately at a distance corresponding to the diameter of the focal spot of the laser beam - from the point of impact of the laser beam. The absorption-improving material can also be used as a lubricant.

It is expedient if the laser beam is directed at the Brewster angle, for example approximately 3.5 °, against the material to be deformed in order to achieve maximum absorption of the energy of the laser beam. The angle is against the plane of the Material web measured so that the laser beam brushes the material. Measured against the vertical on the material web, the Brewster angle can be between 70 ° to 87 °, depending on the type of laser.

In order to reduce the cooling effect that the deformation tool exerts on the material to be deformed when it hits it, it can be provided in a further embodiment of the method according to the invention that the laser beam reflected from the surface of the material to be deformed, the surface of the material deforming Deformation tool, e.g. the roller. If rollers are used as deformation tools, the rollers and the material can be moved such that the directly heated point on the material and the point on the roller heated by the reflected rays reach the entry point into the roll gap at the same time.

In order to reduce or prevent heat flow from the material to be processed via the processing tool, it can be provided in an advantageous embodiment of the method according to the invention that the dissipation of heat when the heated material points come into contact with the forming tool, in particular the rollers, by means of a heat-insulating surface coating of the forming tools , e.g. a glass or ceramic or plastic coating is reduced.

Another embodiment of the method according to the invention provides that the dissipation of heat upon contact of the heated material points with the shaping tool, in particular the rollers, is reduced by supplying heat-insulating liquids or emulsions to the surface of the shaping tools.

Heat energy in a bundled form, for example: as a laser beam, can be supplied in a special application to both the top and the bottom of the material to be deformed. A further embodiment of the method according to the invention is characterized in that the beam from a laser is divided into partial beams, for example by means of beam splitters, and the partial beams are fed to the material to be deformed at different points.

Finally, a partial jet can also be fed to the material to be deformed in front of one of several successive deformation stations, in particular roll stands.

The invention is explained below using schematic exemplary embodiments of devices which are suitable for carrying out the method according to the invention. Show it,

1 is a side view of such a device,

Fig. 2 shows a section along the line II-II in Fig. 1, viewed in the direction of the arrow

P, and

FIG. 3 simplifies an embodiment that has been modified compared to FIG. 1.

In the exemplary embodiments shown in the drawings, the deformation tools are designed as rollers. 1 and 2, the roller 1 is wedge-shaped, and the roller 2 has a V-shaped, all-round groove. The interaction of the two rollers 1 and 2 causes the material 3 to be deformed (rolling stock) to be deformed in a V-shape, as can be seen in FIG. 2. A more or less highly focused laser 4, which is designed as a semiconductor high-power laser, heats the material to be deformed 3 (rolling stock) in the area of the focal spot 10 of the laser 4. The size of the focal spot 10 is chosen so that it covers the area in which of the subsequent deformation in the roll gap between rolls 1 and 2, a noteworthy elongation occurs.

As can be seen from FIG. 1, the more or less well focused laser beam 4 strikes the lower surface of the material 3 to be deformed at an angle 5 (piercing). This allows the focal spot 10 in the immediate vicinity of the roller inlet taking into account the outer contours of the Laser 4 and the edge profile of the beam emitted by the laser. The diameter of the focal spot can be approximately 500 μ.

From the sectional view of FIG. 2 it can be seen that the laser beam 4 strikes the material 3 to be deformed in the form of a strip of material in the plane parallel to the roller axes, the laser beam in a modified embodiment also being at an angle to the material to be deformed Material 3 can be inclined (in Fig. 1, the angle is 90 °). The inclinations of the laser beam 4 to the material 3 to be deformed both in the plane parallel to the axis and in the plane perpendicular to the axis result in a total inclination angle which is equal to the “Brewster” angle (depending on the type of laser lying between 70 and 87 °) Beam at the Brewster angle, maximum energy absorption and minimum reflection of the laser beam 4. The inclination of the laser beam 4 in a plane perpendicular to the roller axes (FIG. 1) also has the effect that, despite the Brewster setting - The angle and thus the maximum absorption, which is still reflected by the material to be deformed, a significant portion of the beam hits and heats the lower roller 2. This reduces the cooling of the material 3 impinging on the roller 2, and under certain circumstances can even improve the heating Coordination of the geometry of the roller and the material 3 to be deformed can even be achieved n that the spots heated by the laser beam 4 on the material 3 to be deformed reach the heated spot on the roller at the same time that the rollers 1, 2 grip the material 3 to be deformed. As a result, the energy of the laser beam is used to a maximum for heating. The inclination of the laser beams 4 with respect to the material to be deformed enables the area swept by the laser beam 4 to be enlarged on the surface of the material to be deformed. This means that the maximum intensity in the center of the focal spot 10 is not as high as with optimal focusing. This prevents melting of the material 3 to be deformed in the focal spot of the laser beam, which would be undesirable for reasons of strength and quality.

Finally, a larger area of the material to be deformed is thereby heated by the laser beam 4, so that even with thicker material 3 to be deformed (Rolling stock), in which the length of the stretched area of the outer fiber is increased, the area of strong deformations is favorably influenced. The setting of the two inclination angles of the laser beam enables the setting of optimal absorption, the setting of the size of the warmed-up area of the material to be deformed and the maximum temperature in such a way that melting of the material 3 to be deformed is prevented, but the deformation is carried out without cracks.

The rollers 1, 2 can be provided with a poorly heat-conducting coating in order to hinder the outflow of heat. The coating 9 of the rollers 1 and 2 can consist of glass, ceramic material or plastic. Absorption-improving material can also be applied to the material to be deformed, before the material to be deformed reaches the focal spot 10 of the laser beam. The absorption-improving material 11 can be sprayed onto the material 3 to be deformed by means of a nozzle 8. For example, graphite can be used as an absorption-improving material. The absorption-improving material 11 can also be used as a lubricant when rolling the material to be deformed.

The action of the laser beam 4 on the material 3 to be deformed is in no way limited to the underside of the material 3 to be deformed; rather, an action of the laser beam 4 on the top of the material 3 to be deformed is also possible. The last-mentioned arrangement is shown in FIG. 3 and is preferably used when a downwardly open curvature is to be produced by rolling.

1 and 2, a temperature sensor 6 is provided for detecting the maximum temperature on the material to be deformed. This temperature sensor, or rather the detection of the maximum temperature on the material 3 to be deformed, can also be used to control the process with regard to uniform heating. The size of the heated area can be checked by a thermal camera 7, which can be used to control the process in connection with image processing. It can be estimated that for the Laser-assisted shaping of material according to the invention, in particular by rolling, requires a 3 mm thick steel sheet at a speed of 10 m / min and a laser power of 7-8 kW, it being possible to use CO2 lasers, Nd: YAG lasers, excimer lasers and diode lasers , Since each of these lasers emits a different wavelength and thus a different Brewster angle occurs, the two beam inclinations must be adjusted according to the laser selected. In addition, other bundled forms of energy can be used, such as plasma rays or microwave rays.

Since a separate roll stand is necessary for the production of each forming step, which - as already mentioned - often results in more than a dozen roll stands in succession, there is one for each of them, the rolls of which produce a deformation that is intolerable to the rolling stock in the cold state Own laser necessary, but with not too complex profiles this means that lasers only have to be arranged with a few rolling stands.

A variant of the exemplary embodiment shown in FIGS. 1-3 for a rolling stand according to the invention consists in that only a part of a beam supplied by a central high-power laser is supplied to this rolling stand via beam splitters and deflecting mirrors, and focusing optics.

Claims

claims:

Process for the production of profiles by non-cutting shaping of material in a shaping station, in particular a rolling station, through which the material is moved, thermal energy being supplied to the material, in particular immediately before the shaping station, characterized in that the thermal energy is bundled, e.g. as a laser beam.

2. The method according to claim 1, characterized in that the heat is supplied in a bundled form, in particular by means of the laser beam to those points of the material at which, following the heating, a sharp bow or angled at an acute angle is produced in the deformation station becomes.

3. The method according to claim 1 or 2, characterized in that (seen in the direction of movement of the material) before the point of impact of the laser beam on the material to be deformed, an absorption-increasing coating, e.g. made of graphite, applied to the material, in particular sprayed on.

4. The method according to claim 3, characterized in that the absorption-increasing coating near the focal spot of the laser beam is applied to the material to be deformed, in particular sprayed on.

5. The method according to any one of claims 1 to 4, characterized in that the laser beam at the Brewster angle, e.g. 3.5 °, is directed against the material to be deformed in order to achieve maximum absorption of the energy of the laser beam.

6. The method according to any one of claims 1-5, characterized in that the laser beam reflected from the surface of the material to be deformed, the material deforming surface of the deformation tool, e.g. the roller.

7. The method according to claim 6, characterized in that the directly heated point on the material and the point heated by the reflected rays on the roller reach the entry point into the roll gap at the same time.

8. The method according to any one of claims 1 to 7, characterized in that the dissipation of heat upon contact of the heated material points with the deformation tool, in particular the rollers, by a heat-insulating surface coating of the deformation tools, e.g. a glass or ceramic or plastic coating is reduced.

9. The method according to any one of claims 1 to 7, characterized in that the dissipation of heat upon contact of the heated material points with the shaping tool, in particular the rollers, is reduced by supplying heat-insulating liquids or emulsions to the surface of the shaping tools.

10. The method according to any one of claims 1 to 9, characterized in that thermal energy in a bundled form, e.g. by means of laser beams.

11. The method according to any one of claims 1 to 10, characterized in that the beam of a laser in partial beams, e.g. divided by means of a beam splitter and the partial beams are fed to the material to be deformed at different points.

12. The method according to claim 11, characterized in that in each case a partial jet of the material to be deformed is fed in front of one of several successive deformation stations, in particular roll stands.