AUTOMATIC GUIDE ADJUSTMENT FROM FEEDBACK OF ROLLING PARAMETERS

Abstract

In a rolling mill in which a hot rolled product is directed by a guide along a delivery path into a roll pass aligned on a mill pass line, a control system is disclosed for correcting any transverse misalignment of the delivery path with respect to the mill pass line. The system compromises an adjustment mechanism for shifting the guide transversely with respect to the mill pass line. Detectors measure a selected parameter indicative of the transverse misalignment and generate status signals representative thereof. A controller responds to the status signals and automatically and remotely operates the adjustment mechanism to correct the misalignment by transversely shifting the guide with respect to the mill pass line.

Description

BACKGROUND

1. Field

Embodiments of the present invention relate generally to control systems for rolling mills producing hot rolled long products, e.g., rods, bars and the like, and are concerned in particular with the automatic adjustment of interstand guides based on the feedback of selected rolling parameters.

2. Description of Related Art

Historically, the dimensional accuracy of hot rolling processes has been monitored manually, such as by burning wooden blocks against the hot rolled products as they travel along the rolling line. In addition to being hazardous, such methods are subject to human error and do not afford operating personnel with sufficient advance notice to make guide adjustments or to stop the rolling process before a cobble occurs, which can result in the costly scrapping of billets and possible damage to mill equipment.

SUMMARY

Broadly stated, embodiments of the present invention address the above described problems by providing a system for monitoring selected rolling parameters indicative of a need to make guide adjustments and for automatically adjusting the guides in response to feedback signals representative of such parameters.

These and other objects, features and advantages of the present invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the entry side of a roll stand equipped with a rest bar assembly and adjustment mechanism of the type employed with exemplary embodiments of the present invention;

FIG. 2 is a side view of the rest bar assembly depicted in FIG. 1, with the nearmost housing post removed;

FIG. 3 is a top plan view of the rest bar assembly depicted in FIGS. 1 and 2;

FIG. 4 is a rearview of the rest bar assembly depicted in FIGS. 1-3;

FIG. 5 is an enlarged partially sectioned top view of a roller guide useful in one exemplary embodiment of the present invention; and

FIGS. 6 and 7 are control diagrams depicting alternative exemplary embodiments of the present invention.

DETAILED DESCRIPTION

The components describes hereinafter as making up the various embodiments are intended to be illustrative and not restrictive. Many suitable components that could perform the same or similar functions as well as the materials described herein are intended to be embraced within the scope of the present invention.

Referring now to the figures, wherein like reference represent like parts throughout the views, embodiments of the present invention will now be described in detail.

With reference initially to FIGS. 1-3, the entry side of a rolling mill roll stand 10 is partially depicted as comprising housing posts 12a,12b and a pair of multi-grooved work rolls 14. The roll stand is arranged along the mill pass line PL in series with other roll stands (not shown).

A roller guide 16 serves to direct a hot rolled product, e.g., a rod or bar, along the mill pass line PL into a roll pass defined by a selected pair of grooves in the work rolls 14. An exemplary embodiment of a rest bar assembly 18 is positioned to support the guide 16 in its operative position.

The rest bar assembly comprises a fixed core 20 extending between and fixed by means of mounting plates 22 to the housing posts 12a, 12b. A saddle 24 on which the guide 16 is mounted, is supported by and movable along the core 20 in opposite directions transverse to the mill pass line PL.

Movement of the saddle 24 is effected by an adjustment mechanism which may comprise a helically cut worm track 26 extending externally along a back side of the core 20. A worm gear 28 carried by the saddle is in meshed relationship with the worm track. The worm gear 28 is keyed or otherwise fixed to a shaft (not shown) rotatively driven remotely by a drive motor 30. While this adjustment mechanism is preferred, other adjustment mechanisms known to those skilled in the art may be alternatively employed in connection with the present invention.

The saddle 24 maybe releasably fixed in place on the core 20 by a remotely operable mechanism, one example being the hydraulically actuated clamp 30 depicted in FIG. 2.

In accordance with an exemplary embodiment of the present invention, and as best depicted in FIG. 5, the guide 16 comprises a pair of arms 32 mounted for pivotal movement about vertical axes defined by pins 34. Pairs of guide rollers 36, 36 and 38, 38 are carried by the arms 32. The forward ends of the arms 32 are resiliently urged apart by springs 40, thereby maintaining the rearward ends of the arms in contact with adjustable stops 42 which include detectors in the form of load sensors 44. The pairs of guide rollers 36, 36 and 38, 38 are configured and arranged to contact and deliver a hot rolled product passing therebetween along a delivery path. The forces F exerted by the rearward ends of the arms 32 on the stops 42 constitute parameters indicative of the position of the delivery path defined by the guide rollers with respect to the mill pass line. Ideally, the delivery path will be aligned concentrically with the mill pass line PL, resulting in the forces F being equal. An imbalance of the forces F indicates a transverse misalignment of the guide rollers with respect to the mill pass line.

As an alternative to the load sensors 44, the guide could be equipped with strain gauges (not shown) to detect any imbalance of forces exerted on the guide, either by misalignment of the product or by an incorrect product size.

In the event that the delivery path is not aligned with the mill pass line PL, a readjustment of the guide is required to correct any imbalance of the forces F.

In accordance with one exemplary embodiment of the present invention as depicted in FIG. 6, an oval process section “O” is being rolled into a round “R” by the work rolls 14. Guide readjustment is effected by a control system comprising a controller 46 arranged to receive and process feedback signals from the load sensors 44 of the guide 16, and to control the operation of the motor 30 and clamp mechanism 31 via control lines 50, 52.

If the feedback signals 48 indicate an imbalance of the forces F exerted by the guide arms 32 against the stops 42, the controller 46 first operates via control line 52 to release the clamp mechanism 31, and then operates via control line 50 and motor 30 to shift the saddle 24 along the core 20 to a position at which the feed back signals 48 indicate that the forces F are equal. The controller then operates via control line 52 and clamp 31 to fix the saddle 24 in its readjusted position on the core 20.

In accordance with another exemplary embodiment of the present invention, as depicted in FIG. 7, a dogbone section “DB” is being slit into multiple rounds R₁, R₂, R₃ by a slitting device 54. The rounds R₁, R₂, R₃ exit the slitting device respectively at velocities V₁, V₂ and V₃. The exit velocities V_1-3 comprise parameters which if unequal, are indicative of transverse misalignment of the guide 16.

Velocity detectors 56 provide the controller 46 with feedback signals 58 representative of the velocities V₁-V₃. The controller 46 corrects any velocity imbalance by operating the clamp 31 and motor 30 to readjust the guide in the same manner as described above with respect to the embodiment of FIG. 6.

While the slitting device 54 has been shown as producing three slit rounds R₁, R₂, R₃, it is to be understood by those skilled in the art that the number of velocity detectors 56 may be varied to match either a lesser or greater number of slit rounds produced by alternative slitting devices.

Claims

1. In a rolling mill in which a hot rolled product is directed by a guide along a delivery path into a roll pass aligned on a mill pass line, a system for correcting any transverse misalignment of the delivery path with respect to the mill pass line, said system comprising: an adjustment mechanism for shifting said guide transversely with respect to said mill pass line;detectors for measuring a selected parameter indicative of said transverse misalignment and for generating status signals representative thereof; anda controller responsive to said status signals for automatically and remotely operating said adjustment mechanism to correct said misalignment by transversely shifting said guide with respect to the mill pass line.

2. The system of claim 1 wherein said guide comprises a roller guide having a pair of rollers between which said product is directed along said delivery path, and wherein said parameter comprises the level of forces exerted by said rollers on said product.

3. The system of claim 1 wherein said roll pass comprises a forming pass followed by a slitting device in which the product is separated into multiple strands, and wherein said parameter comprises the velocities of the strands exiting from said slitting device.

4. The system of claim 1 wherein said guide is mounted for movement along a rest bar extending transversely with respect to said mill pass guide.

5. The system of claim 4 wherein said adjustment mechanism comprises a worm track on said rest bar, a worm gear carried by said guide and in meshed relationship with said worm track, and a servo motor for rotatably driving said worm gear.

6. The system of claim 4 further comprising a clamping mechanism operable between a clamping mode fixing the position of said guide on said rest bar, and a release mode permitting shifting of said guide along said rest bar.

7. The system of claim 6 wherein said clamping mechanism is operated automatically and remotely by said controller.

8. In a rolling mill in which a hot rolled product is directed by a guide along a delivery path into a roll pass aligned on a mill pass line, a system for correcting any transverse misalignment of the delivery path with respect to the mill pass line, said system comprising: a core extending transversely with respect to said mill pass line; a saddle movable along said core;a guide carried by said saddle;an adjustment mechanism for moving said saddle along said core, said adjustment mechanism comprising a worm track on said core, a worm gear carried by said saddle and in meshed relationship with said worm track, and a servo motor for rotatably driving said worm gear;a clamping mechanism operable in a clamping mode to fix the position of said saddle on said core, and in a release mode permitting shifting of said saddle along said core;detector means for measuring a selected parameter indicative of said transverse misalignment and for generating status signals representative thereof; anda controller responsive to said status signals for automatically and remotely operating said adjustment mechanism to correct said misalignment by transversely shifting said saddle with respect to the mill pass line, and for automatically and remotely operating said clamping mechanism to accommodate operation of said adjustment mechanism.

9. In a rolling mill in which a guide directs a hot rolled product along a delivery path into a roll pass aligned on a mill pass line, a method of correcting any transverse misalignment of the delivery path with respect to the mill pass line, said method comprising: measuring a parameter indicative of said misalignment and generating a status signal representative thereof; andcorrecting said misalignment in response to said status signal by transversely shifting said guide with respect to the mill pass line.

10. The method of claim 9 wherein the product is directed along the delivery path between guide rollers, and wherein said parameter comprises the level of forces exerted by said rollers on said product.

11. The method of claim 9 wherein said roll pass comprises a forming pass followed by a slitting guide in which the product is separated into multiple strands, and wherein said parameter comprises the velocities of the strands exiting from said slitting pass.