BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to rolling mills in which laying heads form hot rolled long products into helical ring formations that are deposited on and carried by cooling conveyors to reforming chambers where the rings are gathered into coils, and is concerned in particular with maximizing the density of such coils.
2. Description of the Prior Art
The laying heads of rolling mills are conventionally employed to form hot rolled long products into rings having the same diameter for all product sizes. As herein employed, the term “long products” means round bars and rods, and “size” refers to product diameters.
By way of a non-limiting example, a laying head will produce rings having a diameter of 1075 mm. For products ranging in size from about 5 to 16 mm, rings of this diameter are deposited into and distributed within the reforming chambers to produce reasonably dense and compact coils. However, when the laying heads process larger product sizes, e.g., ranging from 17 to 26 mm, rings with the same diameter tend to resist being satisfactorily distributed in the reforming chambers. The resulting coils thus tend to lack sufficient density, with a somewhat open and random ring distribution that contributes to coil instability.
SUMMARY OF THE INVENTION
In accordance with the present invention, smaller product sizes are formed into conventionally sized rings and larger product sizes are formed into larger rings. The larger rings of the larger size products are less resistant to satisfactory distribution in the reforming chambers, which in turn makes it possible to form more compact and stable coils.
The invention will now be described in further detail with reference to the accompanying drawings, wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic plan view of the delivery end of a conventional rolling mill;
FIGS. 2A and 2B are diagrams depicting the relationship between coil density and product size for different ring diameters;
FIG. 3 is a longitudinal sectional view taken through a laying head;
FIGS. 4A and 4 B are side and front views respectively of interchangeable laying pipes configured to form rings of different diameters;
FIGS. 5A and 5B are side and front views respectively of a laying pipe with interchangeable delivery sections configured to form rings of different diameters;
FIG. 6 is a view of parts of a laying head including dual differently configured delivery sections of laying pipes which are alternatively connected to a common rotatable entry section; and
FIG. 7 is a view similar to FIG. 1 showing interchangeable laying heads, with one having a laying pipe configured to form rings of a diameter different from the diameter of the rings formed by the laying pipe of the other laying head.
DETAILED DESCRIPTION
With reference initially to FIG. 1, the delivery end of a rolling mill is shown comprising the last roll stand 10 from which the hot rolled product exits along a delivery end path “P”. The product is cooled by one or more water boxes 12 before being fed by a pinch roll unit 14 to a laying head 16. The laying head forms the product into a helical formation of rings 18 which are deposited on and carried by a cooling conveyor 20 away from the laying head to a reforming chamber 22 where they are gathered into coils.
As previously noted, the conventional practice has been to form all product sizes into rings having the same diameter. As shown in FIG. 2A, it has been determined that for a given ring diameter, the density of the coils formed in the reforming chamber 22 will decrease as the product sizes increase.
As shown in FIG. 2B, the present invention departs from this conventional practice by increasing the ring diameter for larger product sizes. Coil density for the larger product sizes is thus beneficially enhanced.
With reference to FIG. 3, the laying head 16 comprises a housing 24 enclosing a quill 26 supported by bearings 28a, 28b for rotation about an axis “X”. Quill 26 carries a bevel gear 30 in meshed relationship with a larger bevel gear 32, the latter being driven by conventional means (not shown). A curved laying pipe 34 is carried by a support 36 attached to the front end of the quill. The laying pipe 34 has an entry end 34a aligned on axis X to receive the hot rolled product, and a delivery end 34b spaced radially from the axis X and from which the product is delivered as the helical ring formation 18.
In accordance with one aspect of the present invention, the laying head 16 may be equipped with two or more interchangeable and differently configured laying pipes, two being shown at 34 and 34′ in FIGS. 4A and 4B. Both laying pipes have entry ends 34a, 34a′ configured for alignment on axis X. However, the delivery end of pipe 34b′ is spaced radially from axis X by a radius that is larger than the radius of the delivery end 34b of pipe 34. When processing smaller product sizes, pipe 34 and its appropriately configured support will be installed in the laying head 16. For larger product sizes, pipe 34 will be replaced by pipe 34′, again with its respective appropriately configured support.
In accordance with another aspect of the present invention, as shown in FIGS. 5A and 5B, a segmented laying pipe 38 is subdivided at 40 into an entry section 42 and differently configured and alternatively employable delivery sections 44, 46. The entry section 42 has an entry end 42a leading to an intermediate end 42b, with the entry end aligned on the axis X to receive hot rolled product from the rolling mill. Each of the delivery sections 44, 46 has an entry end 44a, 46a adapted to be positioned to receive the product from the intermediate end 42b of the entry section, and respective delivery ends 44b, 46b spaced from the axis X by different radii. The product exits from the delivery ends 44b, 46b as the helical series of rings 18. With this arrangement, only the delivery sections 44, 46 and respective support components are interchanged alternatively to accommodate either the smaller or larger ranges of product sizes.
In FIG. 6, two differently configured laying pipe delivery sections 48, 50 are fixed with respect to each other and carried by the quill 26 and support 36. The entry ends 48a, 50a of the delivery sections 48, 50 are located 180° apart and spaced from axis X. The exit ends 48b, 50b are spaced by different radii from axis X. A common entry section 52 is rotatably supported within the quill 26 on bearings 54. In the position shown, entry section 52 is adjusted to direct products into the entry end 50a of pipe delivery section 50. By rotatably adjusting entry section through 180°, products will be alternatively directed into the entry section 48a of pipe delivery section 48.
In accordance with still another aspect of the present invention, as shown in FIG. 7, two laying heads 16a, 16b are interchangeably arranged along the processing line. Laying head 16a is equipped with the laying pipe 34 of FIGS. 4A and 4B, and laying head 16b is similarly equipped with laying pipe 34′. When laying head 16a is shifted to the position shown in broken lines at 16a′, the other laying head 16b can be placed on the processing line. The laying heads are thus interchangeable to accommodate different ranges of product sizes.
It should be evident that this disclosure is by way of example, and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention therefore is not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.
Patent Application
20070090223
