GB1581358A - Continuous casting plant for a wide continuously cast strand - Google Patents

Abstract

The guide track for a cast strand (1) has rollers (2) which are equipped with annular recesses (3) to form cylindrical journals (4). The bearings are designed as split rolling bearings (5), preferably self-aligning roller bearings, their parting plane running parallel to the strand guide track. The use of rolling bearings makes it possible for the width of the journal to be considerably smaller than is the case when the usual sliding-contact bearings are used and, as a result, the unsupported regions of the cast strand (1) are reduced. <IMAGE>

Description

(54) IMPROVEMENTS IN OR RELATING TO A CONTINUOUS CASTING PLANT FOR A WIDE, CONTINUOUSLY CAST STRAND (71) We, VEREINIGTE OSTER REICHISCHE EISEN-UND STAHL WERKE - ALPINE MONTAN AKTIENGESELLSCHAFT, a Company organised and existing under the laws of Austria, of Werksgelande, 4010 Linz, Austria, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a continuous casting plant including a supporting structure and rollers defining a strand guide path, which rollers support. guide and straighten or deform a wide, continuously cast strand, such as a steel slab having a width of more than 1,000 mm. wherein the rollers have a small diameter in relation to their length and are provided with a number of annular recesses distributed along their length to form spaced cylindrical necks which are disposed in bearings supported by the supporting structure. Such a continuous casting plant having rollers of this kind is described and claimed in our British Patent No.

1,467.783, to the claims of which attention is directed, having regard to section 9 of the Patents Act. 1949.

Hitherto, such one-piece rollers have been journaled in the strand guide by means of slide bearings, i.e. bearings in which there is sliding contact between the relative ly moving elements. However, slide bearings need to be of a considerable width because of the high loads acting on the rollers, and this results in relatively broad unsupported regions of the cast strand.

Because of the high loads acting on the rollers, the diameter of the bearings and thus also of the rollers. must not be below certain minimum values, and hence the separation between the axes of adjacently arranged rollers cannot be reduced to below a certain value. Consequentlv. the strand surface can bulge and the extraction forces increase. Moreover, slide bearings have a relatively high friction, since the usual conditions, such as low speeds of revolution of the rollers, dictate that either boundary friction or mixed friction prevails. This results in a strong increase in the force needed for extracting the strand.

The terms "mixed friction" and "boundary friction" will be understood from the following. In the lubricant between the sliding faces of a slide bearing, a pressure pack forms upon relative movement of the faces and if the pressure of the liquid accommodates all the bearing force, the sliding faces are completely separated by the lubricating film; a state of hvdrodynamic lubrication and fluid, or hydraulic, friction prevails. This is independent of the bearing materials. If the fluid friction, due to a too great load or a too low sliding speed, is not able to separate completely the sliding faces, partly solid friction and partly fluid friction prevails. This is called "mixed friction". Depending on the proportion of solid friction, more or less wear occurs. The bearing materials influence the behaviour of the bearing. When relative movement between the faces first starts. the considerable static friction must be overcome. With increasing speed, the proportion of the fluid friction increases in the mixed friction, the friction value rapidly decreasing until a minimum is reached. On further increasing the speed of relative movement, the friction becomes fluid friction entirely and the fluid friction begins to increase. Once fully up to running speed. the bearing runs with fluid friction. The friction minimum is the "boundary friction". and it cannot be predetermined exactly. It depends on the oil viscosity (storage temperature), the means surface pressure (load) and the speed. At speeds less than that corresponding to minimum friction, wear occurs, the state of friction being unstable.

The invention aims at avoiding these disadvantages and its object is to provide a continuous casting plant of the above defined kind, which works with greater operational safety, and in which the extraction forces and the unsupported regions of the cast strand are reduced.

According to the invention there is provided a continuous casting plant for a wide, continuously cast strand, comprising a supporting structure, rollers for supporting, guiding, and straightening or deforming the strand, which rollers define a strand guide path, the rollers each being provided with a plurality of annular recesses distributed longitudinally of the respective roller to form spaced cylindrical necks, and bearings supported by the supporting structure, the necks being journaled in said bearings, the bearings being divided anti-friction bearings, and the plane of division extending parallel to the strand guide path.

The term "anti-friction bearing" means either "ball bearing" or "roller bearing".

Advantageously, each bearing has an outer race comprising a first half adjacent the strand guide path and a second half opposite said first half. the half of the outer race of the bearing adjacent the strand guide path being formed by a cover plate whose wall thickness is less than that of the second half of the outer race. Thus bearings of a wider overall diameter can be used. whereby the useful life of the bearing is increased.

Alternatively rollers of a smaller diameter can be used, whereby the distance between the axes of neighbouring rollers can be reduced.

An embodiment of the invention shall now be described. by way of an example only, and with reference to the accompanying drawings, wherein: Figure 1 is a longitudinal section through a roller and its bearings in a continuous casting plant, and Figure 2 is a section through the bearings of two adjacent rollers along line II-II of Figure 1.

In Figure 1. a continuously cast slab 1 rests on, or, if not fully solidified, its strand skin is supported by. a roller 2. The roller is provided with a number of annular recesses 3 along its length. thus forming cylindrical necks 4. Each neck is surrounded by an anti-friction bearing 5, which is in the form of a pendulum roller bearing (also called a self-aligning roller bearing or a spherical roller bearing) in the example illustrated.

Other types of anti-friction bearings could be used. Each bearing is inserted in a housing 6. which is inserted in a corresponding recess 7 of the supporting structure 8 of the continuous casting plant. The housings disposed at the ends of the roller are secured to the supporting structure 8 by wedge connections 9.

Each pendulum roller bearing 5 is divided, the plane of division extending as can be seen from Figure 2, to the strand surface, i.e. parallel to the strand guide path formed by the adjacently arranged rollers. Halves 10' and 10" of an inner race 10 are connected to each other by screws not illustrated. The two-part cage 11 holding bearing rollers 14 is also held together by screws not illustrated. That half 12 of an outer race which takes the load of the strand is inserted in the housing part 6 and fixed by the other half of the outer race, in the form of a cover plate 13, which serves as protection for the bearing rollers 14 and also prevents those rollers 2 supporting the upper surface of the strand from falling out, in the housing part 8 by means of screws 15. Further cover plates (not illustrated) arranged laterally of each bearing protect the bearing from dirt.

The wall thickness of the cover plate 13 is less than the wall thickness of the one half 12 of the outer race accommodating the load. Thereby the structural height of the bearing is reduced, so that either a pendulum roller bearing of as great a diameter as possible having a correspondingly high loading capacity can be installed or a roller with a smaller diameter can be installed without the strand rubbing at the part of the bearing adjacent the strand, even after wear of the rollers. Since anti-friction bearings are used, the cylindrical necks 4 can be shorter, measured along the axis of the cylinder, because the width of an anti-friction bearing is less that that of a slide bearing having an equal loading capacity.

WHAT WE CLAIM IS: 1. A continuous casting plant for a wide, continuously cast strand. comprising a supporting structure. rollers for supporting, guiding and straightening or deforming the strand. which rollers define a strand guide path, the rollers each being provided with a plurality of annular recesses distributed longitudinally of the respective roller to form spaced cylindrical necks, and bearings supported by the supporting structure, the necks being journaled in said bearings, the bearings being divided anti-friction bear ings, and the plane of division extending parallel to the strand guide path.

2. A continuous casting plant, as claimed in Claim 1. wherein each bearing has an outer race comprising a first half adjacent the strand guide path and a second half opposite said first half. said first half being formed by a cover plate and having a wall thickness less than that of said second half.

3. A continuous casting plant as claimed in Claim 1 or Claim 2, wherein said antifriction bearings are pendulum roller bear

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. friction being unstable. The invention aims at avoiding these disadvantages and its object is to provide a continuous casting plant of the above defined kind, which works with greater operational safety, and in which the extraction forces and the unsupported regions of the cast strand are reduced. According to the invention there is provided a continuous casting plant for a wide, continuously cast strand, comprising a supporting structure, rollers for supporting, guiding, and straightening or deforming the strand, which rollers define a strand guide path, the rollers each being provided with a plurality of annular recesses distributed longitudinally of the respective roller to form spaced cylindrical necks, and bearings supported by the supporting structure, the necks being journaled in said bearings, the bearings being divided anti-friction bearings, and the plane of division extending parallel to the strand guide path. The term "anti-friction bearing" means either "ball bearing" or "roller bearing". Advantageously, each bearing has an outer race comprising a first half adjacent the strand guide path and a second half opposite said first half. the half of the outer race of the bearing adjacent the strand guide path being formed by a cover plate whose wall thickness is less than that of the second half of the outer race. Thus bearings of a wider overall diameter can be used. whereby the useful life of the bearing is increased. Alternatively rollers of a smaller diameter can be used, whereby the distance between the axes of neighbouring rollers can be reduced. An embodiment of the invention shall now be described. by way of an example only, and with reference to the accompanying drawings, wherein: Figure 1 is a longitudinal section through a roller and its bearings in a continuous casting plant, and Figure 2 is a section through the bearings of two adjacent rollers along line II-II of Figure 1. In Figure 1. a continuously cast slab 1 rests on, or, if not fully solidified, its strand skin is supported by. a roller 2. The roller is provided with a number of annular recesses 3 along its length. thus forming cylindrical necks 4. Each neck is surrounded by an anti-friction bearing 5, which is in the form of a pendulum roller bearing (also called a self-aligning roller bearing or a spherical roller bearing) in the example illustrated. Other types of anti-friction bearings could be used. Each bearing is inserted in a housing 6. which is inserted in a corresponding recess 7 of the supporting structure 8 of the continuous casting plant. The housings disposed at the ends of the roller are secured to the supporting structure 8 by wedge connections 9. Each pendulum roller bearing 5 is divided, the plane of division extending as can be seen from Figure 2, to the strand surface, i.e. parallel to the strand guide path formed by the adjacently arranged rollers. Halves 10' and 10" of an inner race 10 are connected to each other by screws not illustrated. The two-part cage 11 holding bearing rollers 14 is also held together by screws not illustrated. That half 12 of an outer race which takes the load of the strand is inserted in the housing part 6 and fixed by the other half of the outer race, in the form of a cover plate 13, which serves as protection for the bearing rollers 14 and also prevents those rollers 2 supporting the upper surface of the strand from falling out, in the housing part 8 by means of screws 15. Further cover plates (not illustrated) arranged laterally of each bearing protect the bearing from dirt. The wall thickness of the cover plate 13 is less than the wall thickness of the one half 12 of the outer race accommodating the load. Thereby the structural height of the bearing is reduced, so that either a pendulum roller bearing of as great a diameter as possible having a correspondingly high loading capacity can be installed or a roller with a smaller diameter can be installed without the strand rubbing at the part of the bearing adjacent the strand, even after wear of the rollers. Since anti-friction bearings are used, the cylindrical necks 4 can be shorter, measured along the axis of the cylinder, because the width of an anti-friction bearing is less that that of a slide bearing having an equal loading capacity. WHAT WE CLAIM IS:

1. A continuous casting plant for a wide, continuously cast strand. comprising a supporting structure. rollers for supporting, guiding and straightening or deforming the strand. which rollers define a strand guide path, the rollers each being provided with a plurality of annular recesses distributed longitudinally of the respective roller to form spaced cylindrical necks, and bearings supported by the supporting structure, the necks being journaled in said bearings, the bearings being divided anti-friction bear ings, and the plane of division extending parallel to the strand guide path.

2. A continuous casting plant, as claimed in Claim 1. wherein each bearing has an outer race comprising a first half adjacent the strand guide path and a second half opposite said first half. said first half being formed by a cover plate and having a wall thickness less than that of said second half.

3. A continuous casting plant as claimed in Claim 1 or Claim 2, wherein said antifriction bearings are pendulum roller bear

ings.

4. A continuous casting plant substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawing.