US3378248A

US3378248A - Coil support apparatus

Info

Publication number: US3378248A
Application number: US545355A
Authority: US
Inventors: Francis J Krahe; Stephen J Rybarczyk
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1966-04-26
Filing date: 1966-04-26
Publication date: 1968-04-16
Anticipated expiration: 1985-04-16

Description

April 16, 1968 FQJ. KRAHE E TAL COIL SUPPORT APPARATUS INVENTORS FRANCIS J. KRAHE and STEPHEN J. RYBARCZYK wxww a Filed April 26, 1966 Afro/n ey United States Patent 3,378,248 COIL SUPPORT APPARATUS Francis J. Krahe, Tarentum, and Stephen J. Rybarczylr,

Vandergrift, Pa., assignors to United States Steel Corporation, a corporation of Delaware Filed Apr. 26, 1966, Ser. No. 545,355 2 Claims. (Cl. 263-49) ABSTRACT OF THE DISCLOSURE Apparatus for supporting steel coils in an annealing furnace, including a block of a relatively soft castable refractory material with a central opening lined with a relatively hard refractory material. A metal plate for supporting a first steel coil is placed on top of this refractory, and a tubular column for supporting a second plate and a second steel coil above the first coil is placed on the first metal plate and directly above the hard refractory lining of the base. Lateral passageways for circulation of gases are formed in the refractory base and extend between the central opening and the exterior of the base. These passageways are located entirely beneath the top surface of the refractory.

This invention relates to apparatus for supporting heavy coils of steel strip in a box annealing furnace, and more particularly to apparatus for supporting silicon steel coils one above the other.

Due to the high temperature at which silicon steel coils must be annealed, which is about 2075 F., the steel parts of the apparatus for supporting these coils become so soft during the annealing that they are easily distorted under heavy loads. This distortion has created problems in the use of steel plates on the tops of past coil support bases. Such plates as plate in Egge Patent No. 2,878,- 005 and plate 10 in Tohir Patent No. 2,958,521 have warped at temperatures above 2000 F., due to the load of the bottom coil which it supports and the open areas or passageways beneath the plates which must be provided for the circulation of gases in the furnace. This warping causes undulations in the surface on which the bottom coil is supported, and these undulations mar the bottom edges of the convolutions of the coil, which are in a soft state during their annealing.

An even more severe warping problem with the top plate of the coil support base has been the downward caving-in of the inner lip of the plate around its central opening. This lip supports a tubular column that extends through the axial opening of the bottom coil and which in turn supports a plate for holding a second coil above the bottom coil. The weight of the second coil, the plate on which that coil rests, and the tubular column creates an extremely great load in proportion to the small area of the base plate on which the tubular column rests. The distortion of this plate beneath the inner coil support is thus very severe at the high annealing temperatures used and requires frequent and expensive straightening operations.

Refractory base plates, such as the one shown in Elrick et al. Patent No. 3,082,996, have been substituted for these metal plates. This is a definite improvement over the metal plates and these refractory plates do not warp. However, due to the size of the base which is necessary to support the coils, the refractory plates have been made of pie-shaped sections with crevices in between the sections. At the high annealing temperatures required for silicon steel, the convolutions of the coils become soft and their bottom edges sometimes stick in these crevices, causing damage to both the coil and the base plate when the coil is lifted off of the plate. Furthermore, refractory 3,378,248 Patented Apr. 16, 1968 ice plates are subject to cracking and spalling due to abrasive action or pounding that they often receive when heavy coils are set down upon them.

It is an object of our invention to provide apparatus for supporting heavy coils of steel strip during high temperature annealing which will provide a firm, un- Warped base for a coil to rest on, and will also provide a firm supporting structure for a coil or coils to be sup ported above the bottom coil in the furnace.

Another object is to provide a coil support that will minimize the damage to the edges of the coil which have been caused in the past by either cracks or crevices in the top surface of the support, or by undulations or other deformations in the top surface.

Still another object of our invention is to provide a coil support which will have an increased life with reduced repair expenses.

These and other objects will be more apparent after referring to the following specification and attached drawings in which:

FIGURE 1 is a vertical, sectional view of a portion of a box annealing furnace equipped with the apparatus of our invention; and

FIGURE 2 is a view taken on line 11-11 of FIGURE 1.

Referring to FIGURE 1, a steel base plate 2 on I- beams 4 forms the main support of an annealing furnace 5 in which coils C and C are annealed. The furnace includes a cylindrical inner cover 6 having its lower end resting in a sand seal 8 which is supported on a brick course 10. Other parts of the furnace 5 Outside the cover 6 are not shown in the drawings, but these are of a standard, known construction for box annealing furnaces.

Immediately inside the inner covers 6 and resting on the brick course 10 is a cylindrical outer coil support wall 12. The wall 12 is made of separate refractory tiles 14 each of which has a hole 16 therein. Steel bands 18 in grooves 19 around the wall 12 hold the titles securely together so that the wall is able to support a load without falling apart. The construction of the outer coil supporting wall 12 is old and is described more fully in Elrick et al. Patent No. 3,082,966.

Within the outer coil support wall 12 and supported by the steel base plate 2 is a refractory base 20, having a central opening 21. This base has a. novel construction that solves the problems of supporting coils at high annealing temperatures that were discussed above. It includes a block 22 made of a castable refractory material. Since the hydrogen atmosphere of the furnace reacts with iron to produce water, it is important that this refractory material have a low iron content, to keep to a minimum the formation of water droplets in the furnace. An example of a suitable material for block 22 is a product called Hot Top Moldit," available from Refractories and Insulation Corporation of Pittsburgh, Pa. This castable material is generally softer and more shock resistant than most other types of refractories.

The base 20 has mounted within its central opening 21 a fan 26, driven by a motor 28. Also in the base 20 are nine passageways 30, having linings 32 which are preferably of stainless steel but may be of hard brick. These passageways radiate from the central opening 24 at the level of fan 26 and allow the atmosphere in opening 24 to be blown by the fan 26 through the base 20 and into the annular space between the block 22 and the outer support wall 12. Three vertical

hydrogen supply pipes

34, 36, and 38 extend through the base plate 2 and refractory block 22 and communicate with three of the passageways 30.

In forming the block 22, the castable refractory material should be poured into a suitable mold form to the level of the bottoms of horizontal passageways 30. Then, the stainless steel linings 32, forming the nine passageways 30, are set down on top of the refractory material in the pattern shown in FIGURE 2. More refractory material is then poured over these ducts up to the level of the top surface 40 of block 22 (FIGURE 1) leaving the passageways 30 entirely surrounded by refractory material. The entire mass of refractory material that has been poured is then allowed to set and form a single monolithic block.

In addition to the castable refractory block 22, the refractory base 20 also includes a hard brick wall 42 lining the opening 21 in the base. This wall extends up to the same level as the top surface 49 of block 22, and the portions of the wall between the inner ends of the passage- Ways 30 form uninterrupted vertical columns that are capable of supporting a heavy load without cracking or spalling. The bricks used in constructing the wall 42 should be of a harder material than the soft castable material of the block 22. A suitable material for this wall is Varnon Brick, a high temperature brick manufactured by Harbison-Walker Refractories Company. This material should also be of low iron content to keep to a minimum the formation of water droplets in the furnace. On top of the refractory base 20 is placed a steel plate 44 having a central opening 46 which has the same diameter and is aligned with the opening 21. Also, the outer circumference of the plate 44 is aligned with the outer circumference of the base 26). A bottom coil C is placed on top of the steel plate 44 and has an axial opening A that is larger than the diameter of the central opening 46 in plate 44. Through the central opening A is inserted a tubular column 48 which may be made of steel and which rests on the inner portion of the steel plate 44. On top of the column 48 is placed another steel plate 5ft which supports a second coil C. The plate 50 is also supported by the outer coil support wall 12, and the load of the coil C and the plate 56 is divided between the Wall 12 and the tubular column 48. If the annealing furnace is designed to hold three Coils within each inner cover, another tubular column 52 is placed on top of the inner edge of plate 5%, and the outer coil support wall 12 is extended upward from the plate 50 as shown in FIG- URE 1. The plate for supporting the third coil is not shown in FIGURE 1, but its structure and mounting are exactly the same as the plate 50 for the second coil C. From the above description of one embodiment of our improved coil supporting apparatus it can be seen that the coil C is given firm support by the single, smooth plate 44, which is in turn resting on the base 20 with every part of its bottom surface in contact with the top of the base. This type of support prevents the deformation of plate 44 at high annealing temperatures, yet provides a coil support surface that will not spall or contain crevices that cause damage to the edges of the coil windings. Furthermore, the inner edge portion of the plate 44 does not sag at high annealing temperatures under the extremely heavy load imposed by the tubular column 48 and the upper coils supported thereby. This sagging is prevented by the provision immediately beneath the inner edge portion of the plate 44 of the hard refractory wall 42, including uninterrupted vertical columns of refractory material between the inner ends of passageways 30. The wall 42, made of separate bricks and mortar, has been found to be capable of supporting its heavy load without cracking or spalling. At the same time, the softer, more shock resistant, castable refractory block 22 does not crack under the load of the bottom coil C, because it is of a monolithic block construction, interrupted only by relatively small passageways, reinforced by linings of either stainless steel, or hard brick.

While one embodiment of our invention has been shown and described, various modifications will be apparent while remaining within the scope of the appended claims.

We claim:

1. Apparatus for supporting in an annealing furnace heavy coils of steel strip having central axial openings therethrough comprising:

a refractory base having a flat, substantially horizontal top surface and a central vertical opening extending to the top surface, the refractory base supporting a first coil of strip with its axial opening substantially vertical, the diameter of said axial opening being substantially greater than the diameter of the vertical opening in said base,

said refractory base having substantially horizontal passageways extending from said central opening to the exterior thereof and said passageways being located entirely beneath the top surface of said base,

said refractory base including a refractory block made of a relatively soft refractory material and uninterrupted vertical columns of a relative hard refractory material lining the central opening in said base and extending from the top to the bottom of the central opening between the inner ends of said passageways,

a tubular column supported by said vertical columns within the opening of said first coil, and

a plate for supporting a second coil mounted on top of said tubular column.

2. Apparatus of claim 1 including a flat, horizontal metal plate resting on flat top surface of said base with a central opening aligned with and having substantially the same diameter as the vertical opening in said base, said metal plate having its inner edge portion around said central opening supported by said vertical columns of hard refractory material, and said inner edge portion in turn supporting said tubular column and said plate for supporting a second coil.

References Cited UNITED STATES PATENTS 1,564,235 12/1925 Harrington 2665 1,739,958 12/1929 Farmer 263-49 2,325,677 8/1943 Hoak 266-5 3,082,996 3/1963 Elrick et a1. 263-49 FREDERICK L. MATTESON, 111., Primary Examiner.

JOHN J. CAMBY, Examiner.