GB2141959A

GB2141959A - Rolling mill

Info

Publication number: GB2141959A
Application number: GB08415722A
Authority: GB
Inventors: Kenneth Thomas Lawson; David Robert Howard
Original assignee: Davy McKee AG
Current assignee: Davy McKee AG
Priority date: 1983-06-23
Filing date: 1984-06-20
Publication date: 1985-01-09
Also published as: GB8415722D0

Abstract

A rolling mill stand has a pair of spaced apart housing structures (20), with upper and lower roll assemblies (2, 4, 6, 8) including roll chock assemblies (14, 16) held in these housing structures. Hydraulic jacks (22) are arranged to adjust crossing of the upper and lower rolls by moving roll chuck assemblies (14, 16) relative to the housing structures (20). For each roll chock assembly (14, 16) which is to be moved there is a bearing member between the surfaces of the chock assemblies and the housing structures, allowing the chock assemblies to move relative to the housing structures, thus permitting crossing adjustment of the rolls when the mill is in use. <IMAGE>

Description

SPECIFICATION Rolling mill This invention relates to a rolling mill of the type having upper and lower roll assemblies and where at least one of these assemblies can be adjusted so that the axis of the roll(s) of one assembly is inclined horizontally to the axis of the roll(s) of the other assembly.

In such mills, the purpose of horizontally inclining or crossing the axes of the rolls is to provide a metal strip rolled with a desired contour and, thus, to have an effect on the shape of the metal strip.

Generally, hydraulic or mechanical jacks are provided within the side walls of the mill housings and these jacks bear against the roll chock assemblies of the rolls in order to adjust the position of the roll chocks and, hence, the horizontal inclination of one roll assembly with effect to the other roll assembly. However, because of the extremely high rolling loads which are applied to the bearing chock assemblies when the mill is in use to roll metal, it has only been possible to make these adjustments while the mill is not in use, thus increasing the "down" time of the mill and preventing alteration of the crossing of the rolls while the strip is being rolled.

An object of the present invention is to provide a rolling mill in which this adjustment of the crossing of the rolls can be made while the mill is in use.

According to the present invention there is provided a rolling mill stand comprising: a pair of spaced apart housing structures; upper and lower roll assemblies including roll chock assemblies held in the housing structures; means for adjusting crossing of the upper and lower rolls by moving at least one of the roll chock assemblies relative to the housing structures; and for each roll chock assembly which is to be moved, bearing means allowing crossing adjustment in use.

It is possible that one roll assembly has fixed rolls and for the other roll assembly to have means for adjusting the bearing chock assembly of this roll assembly so that this roll assembly can be inclined to the fixed assembly.

In an alternative embodiment, both roll assemblies are provided with means whereby the bearing chock assemblies of the roll assemblies can be moved so that a greater degree of crossing between the rolls can be obtained.

In this case, each of the movable bearing chock assemblies has a bearing member located between it and the adjacent horizontal surface of the housing structure against which it would otherwise abut.

In order that the invention may be more readily understood, it will now be described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a diagrammatic elevation of a rolling mill in accordance with the invention; Figure 2 is a section on the line Il-Il of Fig.

1; and Figures 3 and 4 are scrap views of part of the mill shown in Fig. 2 showing alternative arrangements.

Referring to Fig. 1, a rolling mill has an upper roll assembly consisting of an upper work roll 2 backed up by an upper back-up roll 6. There is also a lower roll assembly consisting of a lower work roll 4 backed up by a lower back-up roll 8. The ends of these rolls are supported in roll bearing chock assemblies which, in turn, are located in windows 1 8 defined by a pair of spaced apart vertical housing structures 20.

As shown in Fig. 1, the two rolls of the upper roll assembly can be horizontally inclined to the rolls of the lower roll assembly, i.e. the rolls can be "crossed".

Referring now to Fig. 2, the upper back-up roll 6 is supported at its ends in bearing chocks 14 in which are nested bearing chocks 10 for the upper work roll 2. Similarly, the lower back-up roll 8 is supported at its ends in bearing chocks 1 6 in which are nested bearing chocks 1 2 for the lower work roll.

In the wall of each housing which defines the vertical sides of the window 18, there are positioned hydraulic jacks 22 which act against the side wall of the chocks through pads 24. Considering each roll assembly in turn, if a jack on one side of the roll axis on one chock assembly and a jack on the opposite side of the roll axis on the assembly at the other end of the roll are energised together to engage with the bearing chocks, then these chocks are moved sideways in opposite directions in the housing windows and this causes the roll assemblies to be displaced so that their longitudinal axes are horizontally inclined to the normal axes of the rolls.If the jacks acting on one roll assembly are operated in the opposite direction to the jacks corresponding to the other roll assembly, then the roll assemblies can be caused to cross so that the axes of the upper rolls are inclined horizontally to the axes of the lower rolls.

It will be appreciated that, when the mill is in use, the rolling load passes through the rolls, and hence, through the bearing chock assemblies into the massive mill housings.

When the rolls are rolling metal, it has heretofore been impossible to displace the bearing chock assemblies because of the huge friction forces which apply between the upper surfaces of the bearing chocks and the adjacent surfaces of the housings against which the bearing chock assemblies abut. The present invention serves to overcome this by introducing a bearing member between the surfaces of the bearing chock assemblies and the housings which normally abut each other. The purpose of the bearing member is to permit the bearing chock assemblies to move relative to the housings, even when the mill is on load.

In the arrangement shown in Fig. 2, the bearing member consists of top and bottom plates 28, 30 sealed together with edge seals 32 and fluid under pressure is maintained between these plates. The fluid may be oil, grease or a gas. This bearing member reduces the friction between the upper surface of the bearing chock assembly and the adjacent surface of the housing and permits relative movement to take place between them.

In the embodiment shown in Fig. 3, the bearing member comprises a pair of wear plates 34 and a series of hard steel rollers 36 located between these plates. The rollers can be as illustrated in Fig. 3 or they can be arranged in the well known form as recirculating roller bearings.

In the embodiment shown in Fig. 4, there is positioned, between the upper surfaces of the chock assembly and the window, a bearing member comprising a pair of plates 38 having sandwiched therebetween a pad 40 of hard but elastic material which may be rubber, polyurethane or any other suitable material.

In all the embodiments described in this specification, the purpose of the bearing members is to reduce the friction load between bearing chock assemblies and the housings such that it is possible to adjust the degree of roll crossing during the time that the mill is in use and is rolling material; The supply of hydraulic fluid under pressure to the jacks 22 may be controlled by means of signals received from a shapemeter downstream of the mill so that the degree of roll crossing and its effect on the contour or shape of the strip produces strip conforming with present day requirements.

In the arrangement shown in the figures, each roll assembly consists of a work roll and a back-up roll, but each assembly could comprise a single roll.

Bearing members are located between the underside of the chocks of the lower roll assembly and the horizontal surfaces of the housing windows if it is intended to displace the lower roll assembly.

Claims

1. A rolling mill stand comprising a pair of spaced apart housing structures; upper and lower roll assemblies including roll chock assemblies held in the housing structures; means for adjusting crossing of the upper and lower rolls by moving at least one of the roll chock assemblies relative to the housing structures; and for each roll chock assembly which is to be moved, bearing means allowing crossing adjustment in use.

2. A rolling mill stand as claimed in claim 1, wherein the bearing means is between the top of the upper or the bottom of the lower roll chock assembly and the adjacent part of the housing structures.

3. A mill stand as claimed in claim 1 or 2, wherein the bearing means comprises a pair of plates sealed together with edge seals for relative lateral movement and having pressurised fluid therebetween.

4. A mill stand as claimed in claim 1 or 2, wherein the bearing means comprises a series of hard steel rollers.

5. A mill stand as claimed in claim 2, 3 or 4, wherein the bearing means comprises, a pair of plates with sandwiched between them a pad of elastic material.

6. A mill stand substantially as herein described with reference to Figs. 1 and 2 and/or Fig. 3 or 4.