GB2154168A

GB2154168A - Rolling stand and method of flat rolling metal strip in a rolling stand

Info

Publication number: GB2154168A
Application number: GB08503570A
Authority: GB
Inventors: Wilhelm Bolte; Johann Liedtke
Original assignee: SUNDWIGER EISEN MASCHINEN; Sundwiger Eisenhutte Maschinenfabrik Grah and Co
Current assignee: SUNDWIGER EISEN MASCHINEN; Sundwiger Eisenhutte Maschinenfabrik Grah and Co
Priority date: 1984-02-14
Filing date: 1985-02-12
Publication date: 1985-09-04
Also published as: IT8547678A1; IT1182195B; FR2559405B1; FR2559405A1; DD233955A5; IT8547678A0; GB8503570D0; DE3405146C1

Abstract

A multi-roller rolling stand has guide rollers 3, 7 which are arranged upstream and downstream of the 3 rolling stand 5 in the strip run direction, and are skewable about pivot axes 9, 10 arranged at right angles to said roller axes and in the centre of each roller in order to influence the strip run. Wandering of the strip is detected by sensors 14, 15 and is counteracted by pronounced skewing of guide rollers 3, 7 via adjusting devices 11, 12 under the control of regulating device 13. The central adjustment of the strip run is made before the rolling and is maintained upon commencement of the rolling and during the rolling by continual correction. The central adjustment of the strip run is made before the rolling and is maintained upon commencement of the rolling and during the rolling by continual correction. The advantage of such a rolling stand lies in the fact that the strip is rolled to close tolerances within the region of the rolling calibre with a maximum cross-sectional reduction per pass. <IMAGE>

Description

SPECIFICATION Rolling stand and method of flat rolling metal strip in a rolling stand The invention relates to a rolling stand, particularly multi-roller rolling stand, for flat rolling metal strip, having guide rollers arranged upstream and downstream of the rolling stand in the strip run direction, and wrapped by the strip, of which at least one is skewable relative to the strip run direction by means of an adjusting device for the purpose of influencing the strip run direction.

It is well-known to divide by slitting shears wide strip, which has been produced by hot rolling and wound into bundles, into medium and/or narrow strips, which strips are then likewise wound into bundles and further rolled or finish rolled by cold rolling. Not infrequently, the hot-rolled wide strip exhibits a non-uniform thickness profile (convexconvex). The medium and/or narrow strips produced from the marginal regions of such a wide strip have a trapezoidal cross-section. During the rolling of such strips, the strip tends to wander laterally in the roll gap, although it is clamped under traction between the outgoing reel and the incoming reel. The wandering of the strip in the roll gap can be counteracted by decreasing the reduction per pass. However, this simultaneously means an increase in the number of passes required for the overall reduction.

In order to influence the strip run direction, it is known to employ guide rollers which are skewable relative to the strip run direction so that one edge of the strip comes in onto the roller earlier than the opposite edge of the strip (Verein Deutscher Eisen hüttenleute, Herstellung von kaltgewalztem Band "Production of cold-rolled strip", Part 1, 1970, Verlag Stahl-Eisen mbH, Dusseldorf, pages 101-105; German Utility Design, 8,112,755). In the case of these known guide rollers for adjusting and/or correcting the strip run direction, their pivot axes are located outside the roller centre and/or strip centre.

Attempts with the known guide rollers to control the strip run during the flat rolling of the medium or narrow strips of trapezoidal cross-section obtained from the marginal regions of a longitudinally divided wide strip have not led to a satisfactory result.

The object of the invention is to provide a rolling stand and a method of flat rolling a metal strip by which a laterally wandering of the strip during the rolling is prevented.

This aim is achieved in a rolling stand of the type initially mentioned, when the pivot axis for the skewing of one or both of the guide rollers is located in the central region of the rollers and/or the strip and that the adjusting device is coupled to a controlling which detects the strip run upsteam and downstream of the roll gap by sensors and delivers an adjusting signal to the adjusting device in the case of a deviation between desired value and actual value.

A further development of the invention consists in that each guide roller is associated with a deviating roller, the outgoing line and/or incoming line of the envelope region contacting the strip is located in a plane with the roll gap.

As regards the method, the aim is achieved in the case of the rolling stand according to the invention when the central strip run is obtained by adjusting at least one guide roller with the strip running before commencing rolling and is maintained from the commencement of rolling and during the rolling.

The lateral force causing the lateral wandering of the strip, which is a function of the rolling force, of the strip profile and of the speed, is counteracted under strip traction by more or less pronounced skewing of one or both of the guide rollers from the outset, so that it is impossible for a major lateral force, which cannot be overcome by the adjusting device, to develop at all. The strip can therefore be maintained, throughout the entire rolling operation, in the region of the rolling calibre in which it can be rolled with the closest tolerance.

Because the strip can be rolled with full rolling force at full speed, one or more rolling passes and intermediate annealings are economised.

In the accompanying drawings: Figure 1 shows a multi-roller rolling stand with strip guide means in side elevation, Figure 2 shows the multi-roller rolling stand according to Figure 1 in plan and Figure 3 shows a non-uniform thickness profile of a hot-rolled wide strip, wherein A = undivided width and B, C and D = widths after division.

In the drawing showing an embodiment of the invention from an outgoing reel 1, the strip 2 runs over a first guide roller 3, a second guide roller 4 into the roll gap of a multi-roller rolling stand 5. On the exit side the strip runs over a third guide roller 6 and a fourth guide roller 7 to a winding reel 8.

The guide rollers 3, 7 are wapped by the strip 2.

The degree of wrap is amplified by the further guide rollers 4, 6 which guide the strip in a straight line through the roll gap of the multi-roller rolling stand 5.

The guide rollers 3, 7 are arranged skewably about pivot axes 9, 10, which are arranged in the centre of the rollers at right angles to the roller axes, by means of an adjusting device 11, 12 which is modulated by a controlling device 13 having sensors detecting the strip edges.

The function of the multi-roller rolling stand with strip guide means according to the invention is as follows: At minimum strip speed, and before the rolling, the central strip run is adjusted by more or less pronounced skewing of the guide rollers 3, 7. Because the guide rollers 3, 7 are pivoted about the central pivot axes 9, 10, no one-sided over-stretching of the strip occurs. As soon as the rollers of the multi-roller rolling stand 5 are applied, in the case of an asymmetrical profile a lateral force develops, which generates the tendency to wander in the strip 2. The slightest wandering is detected by the sensors 14, 15 and reversed by more or less pronounced skewing via the controlling and regulating device 13 and the adjusting devices 11, 12. Be cause the lateral forces are counteracted as soon as they appear, the necessary counterforces are small and can easily be balanced by the adjusting devices 11, 12. This means that the rolling stand can ultimately be operated with full rolling force and maximum speed. This has favourable effects both as regards productivity and as regards the tolerances of the strip.

Claims

1. Rolling stand, particularly multi-roller rolling stand for flat rolling metal strip, having guide rollers arranged upstream and downstream of the rolling stand in the strip run direction, and wrapped by the strip, of which guide rollers at least one is skewable relative to the strip run direction by means of an adjusting device for the purpose of influencing the strip run direction, characterised in that the pivot axis for the skewing of one or both of the guide rollers is located in the central region of the rollers and/or of the strip and that the adjusting device is coupled to a controlling device which detects the strip run upstream and downstream of the roll gap by sensors and delivers an adjusting control signal to the adjusting device in the case of a deviation between desired value and actual value.

2. Rolling stand according to Claim 1, characterised in that each guide roller is associated with a deviating roller the outgoing line and/or incoming line of the envelope region contacting the strip is located in a plane with the roll gap.

3. Method of flat rolling metal strip in a rolling stand according to Claim 1, characterised in that the central strip run is obtained by adjusting at least one guide roller with the strip running before commencing rolling and is maintained from the commencement of rolling during the rolling.