US3923556A

US3923556A - Formation of open coil with spacer band

Info

Publication number: US3923556A
Application number: US420917A
Authority: US
Inventors: Ludwig C Iszczukiewicz
Original assignee: Lee Wilson Engineering Co Inc
Current assignee: Lee Wilson Engineering Co Inc
Priority date: 1973-12-03
Filing date: 1973-12-03
Publication date: 1975-12-02
Anticipated expiration: 1992-12-02
Also published as: BR7409967A; BE822894A; GB1437558A; DE2456124A1; CA1024493A; FR2253096A1; IT1026727B; JPS5086409A

Abstract

Process and means are disclosed for forming an open coil of strip metal, such as steel strip, in which the convolutions of the coil are spaced apart to permit passage of treating gases through the spaces for treating the material of the strip. A spacer band or web is interwound with the strip as it is wound into a coil to achieve the desired spacing of the convolutions, the spacer being substantially the same width as the strip and having elongated members extending transversely of the strip which are stiff enough to restrict undesirable bending of the strip across its width. The spacer also includes elongated members that extend generally longitudinally of the strip and that are flexible enough to form the coil. The spacer band acts as a structural member that supports the metal strip during forming and handling of the open coil and during treating of the strip, and thus promotes the successful formation, handling, and treatment of open coils of very thin metal, for example steel strip as thin as 0.003 inch in thickness.

Description

United States Patent 11 1 Iszczukiewicz 1 1 Dec. 2, 1975 [75] Inventor: Ludwig C. Iszczukiewicz, Maple Heights, Ohio [73] Assignee: Lee Wilson Engineering Company,

Inc., Cleveland, Ohio [22] Filed: Dec. 3, 1973 [21] Appl. No.: 420,917

[52] U.S. Cl. 148/16; 148/6.35;148/14;

148/16.7; 148/20.3; 148/156; 242/781 [51} Int. Cl. C2lD l/74; C21D 9/68 [58] Field of Search 148/16, 16.7, 155, 156,

Primary E.taminerC. Lovell Attorney, Agent, or FirmBosworth, Sessions & McCoy [57] ABSTRACT Process and means are disclosed for forming an open coil of strip metal, such as steel strip, in which the convolutions of the coil are spaced apart to permit passage of treating gases through the spaces for treating the material of the strip. A spacer band or web is interwound with the strip as it is wound into a coil to achieve the desired spacing of the convolutions, the spacer being substantially the same width as the strip and having elongated members extending transversely of the strip which are stiff enough to restrict undesirable bending of the strip across its width. The spacer also includes elongated members that extend generally longitudinally of the strip and that are flexible enough to form the coil. The spacer hand acts as a structural member that supports the metal strip during forming and handling of the open coil. and during treating of the strip, and thus promotes the successful formation, handling. and treatment of open coils of very thin metal, for example steel strip as thin as 0.003 inch in thickness.

6 Claims, 6 Drawing Figures US. Patent Dec. 2, 1975 3,923,556

FORMATION OF OPEN COIL WITH SPACER BAND BACKGROUND OF THE INVENTION This invention relates to the annealing or other treating of strip metal in which the strip is wound into an open coil in which the convolutions of the coil are spaced apart and treating gases are passed between the convolutions to effect treatment of the metal of the strip; and more particularly this invention relates to process and means for spacing apart the convolutions in the coil and maintaining the stability and form of the open coil during processing and handling.

The invention will be disclosed hereafter in connection with the forming of open coils of steel strip for such treating purposes since it provides exceptional advantages in such use, although it may be used for forming open coils of other strip material.

In the treating, as annealing, of steel strip in which the strip is would into an open coil, the open coil is heated to as high as 1750F. by passing a suitable heated atmosphere through the spaces between the convolutions of the coil, as by the process and apparatus disclosed in Wilson & Corns US. Pat. 3,114,539. Other open coil treatments may involve modifying the chemical composition of the strip metal. For example, the carbon content of steel strip may be modified by the use of a suitable atmosphere. Furthermore, treatments may involve oxidation, bright annealing, gas alloying, and treatments involving the application to the surfaces of the strip metal materials that will react with constituents of the metal and the treatment of the surfaces by passing heated gases between the spaced strip convolutions. The Lee Wilson US. Pat. 3,109,877 discloses advantageous methods of modifying the composition of the metal, which can be used in conjunction with the present invention.

Various processes and means have been used or proposed to separate the convolutions of a strip wound in an open coil, and to keep the convolutions separated during coiling, handling, and treating of the coil.

The problem is considerably more difficult when the strip is of light gauge, as from about 0.003 inch to 0.035 inch thick, and when the strip is of substantial width as from about 18 inches to as much as 72 inches. Strip steel of such small thicknesses and substantial width may bend or distort during the forming or handling of the open coil and change in form during the heat treatment due to thermal effects. Such distortion may cause the convolutions to contact each other so that all parts of the strip do not receive uniform treatmentand the quality of the product may be reduced by distortion of the coil.

SUMMARY OF THE INVENTION The invention comprises a process of forming an open coil of metal strip in which the convolutions of the strip in the coil are spaced to permit passage of gas therebetween, comprising winding the strip into a coil simultaneously with a longtudinal spacer band or web so that the spacer band is located between the convolutions of the strip. The spacer band is of substantial width, being at least as wide as a major portion of the width of the strip and preferably is substantially as wide as the strip for maximum support of the strip. The band is sufficiently longitudinally flexible to be wound be tween the convolutions of the strip in the coil. Transversely of the strip the band is sufficiently stiff to resist transverse bending of the strip and resulting distortion of the coil. The spacer band is formed of spaced interconnected elongated metal elements that are laterally offset to permit adequate flow of gas between adjacent convolutions of the coil transversely of the convolutions, i.e., axially of the coil. The invention also comprises a method of treating coils of strip with a gaseous atmosphere in an open coil treating operation, the convolutions of the open coil being spaced by such a spacer band. The invention also comprises an open coil of metal strip having such a spacer band incorporated therein, and such a spacer itself.

The spacer band acts as a structural element contacting a large area of the metal strip during the winding of the coil, during handling of the coil, and during treatment. This structural element prevents distortion of the convolutions of the coil that could cause them to contact each other and produce the above indicated disadvantages. The spacer band element can be recovered and reused on rewinding of the open coil into a tight coil.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other advantages and features of the invention will be apparent from the following description of the invention in connection with the accompanying drawings in which:

FIG. 1 illustrates the winding of an open coil with a spacer band embodying the invention between the convolutions of the coil;

FIG. 2 is a perspective showing a portion of a preferred spacer band embodying the invention, to a scale larger than that of FIG. 1;

FIG. 3 is a perspective to an enlarged scale of a portion of the open coil of FIG. 1 showing spaced coil convolutions separated by a preferred spacer band embodying the invention, the thicknesses of the metal strip and the spacer band being exaggerated for clarity;

FIG. 4 is a section along line 4-4 of FIG. 3 ofa portion of an open coil embodying the spacer band of FIG. 3 between the convolutions of the coil, the scale being larger than that of FIG. I;

FIG. 5 is a side view of another form of spacer band embodying the invention that may be used according to the invention; and

FIG. 6 is a cross sectional view similar to FIG. 3 but showing a portion of a coil embodying the invention and embodying the spacer band of FIG. 5.

DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1, a strip of metal S emanating from a suitable source, such as a conventional. tightly wound coil C of strip of the desired thickness and width, that is supported on a known rotatable payoff turntable 1, comprising a generally flat disc portion 2 and central mandrel 3, supported for rotation about a vertical axis. The strip S passes from coil C to a coil C' that is supported on a known power-driven rotatable turntable 4 mounted for rotation about a vertical axis and comprising a generally flat disc portion 5 and a known collapsible mandrel 6. The strip is thus rewound into an open coil C having spaced convolutions X.

Disposed between the freely rotatable payoff tumtable 1 and the power driven recoiling turntable 4 is a known tension control apparatus 7 which is adapted to impose the desired amount of back-tension on the strip that is being recoiled. Apparatus of this type is disclosed in the above noted Wilson and Corns US Pat. No. 3,114,539 which is incorporated herein by reference to the extent that its disclosure is applicable. Another turntable 8, supported for rotation about a vertical axis, includes a disc portion 9 and a suitable mandrel 10. A coil C" of spacer band Y embodying the invention, in this embodiment is substantially as wide as the strip S, passes between guide rollers 12 and is wound into the coil C between the convolutions X of the coil.

A portion of the spacer band Y of FIG. 1 is shown in FIG. 2. It comprises a reticulated structure made up of spaced substantially parallel elonated members such as wires 13 that extend transversely of the strip S, connected to spaced substantially parallel elongated members such as wires 14 that extend longitudinally of the strip S when the spacer is in place. The wires 13 are fixed as by spot welding to wires 14 in such manner that there are no sharp edges or protrusions that can scratch or otherwise harm the surfaces of the convolutions of the coil. Furthermore, it is preferable, as is shown in FIGS. 2 and 3, that wires 13 are all on one side of the longitudinally extending wiresl4so that, as shown in FIG. 3, when the spacer band Y is located between the convolutions X of the coil and the coil is being treated in an oven by passage of heated gas between the convolutions of the coil, there is substantially unimpeded flow of the treating gas between the convolutions, as is shown by the arrows G. The only contacts between the convolutions of the coil and the spacer occur where the

members

13 and 14 contact the convolutions. Preferably, as is shown, the cross sections of the

members

13 and 14 are circular; this makes possible lower cost construction because these parts can be made of readily available wire or rod, and makes possible minimal contacts of the spacer with the convolutions of the coil because of the contacts provided by the circular cross

secitonal members

13 and 14 have essentially only line contacts with the surfaces of the metal strip forming the coil convolutions.

Preferably, transverse members 13 and longitudinal members 14 are sufficiently stiff that during winding, handling, heat treatment, cooling, and subsequent handling of the open coil the wires support the convolutions of the strip from undersirable bending and distortion. Furthermore, the longitudinal members 14 are sufficiently flexible so that they permit the spacer band to be readily wound between the convolutions of the coil without damaging them. It is preferable that the members 13 be stiffer than the longitudinal members 14 so the band is stiffer and substantially less flexible transversely than longitudinally of the metal strip forming the coil convolutions.

The spacer band Y is preferably formed of metal which resists corrosion, does not react or stick to the metal of the strip in the convolutions, and lends itself to reuse. For these reasons stainless steel may advantageously be used.

While the spacer band of FIG. 2 is practicable and of relatively low cost, other types of spacer bands may be used in the invention, such as spacer band Z shown in FIGS. and 6. This spacer is similar to a type of known conveyor belt. It comprises substantially parallel elongated members 16 which may take the form of stiff rods or wires that are connected by members 17 that extend generally longitudinally of the band and hence of the strip. Members 17 are flattened helices, the vertices 18 of which are looped between the vertices of the flattened helices formed by adjacent members 17 with the transverse members 16 extending through the loops 18 thus formed. The spacer band Z thus is substantially flexible longitudinally and substantially stiff transversely of the spacer band and of the strip.

When interwound between the convolutions of a coil, as by the apparatus and process illustrated by FIG. 1, the resulting open coil has the spacer Z between the convolutions thereof, and a substantially unobstructed gas flow is permitted. As shown, the

members

16 and 17 are of circular cross section and thus each of these members makes only minimal contact with the surfaces of the strip convolutions, so that the gas atmosphere can contact essentially the entire surface of the convolutions for treatment purposes. This form of spacer band is also preferably made of stainless steel or other material that is heat and corrosion resistant, that will not react with the metal of the strip X, and that may be recovered on rewinding of the open coil into a tight coil and be re-used again.

By use of a spacer band embodying the invention, such as either of those illustrated above, preferably where the spacer extends substantially for the full width of the strip, strips of steel or other metal of substantial width and quite thin can be successfully wound into open coils that can be handled and heat treated, without material bending, collapsing or contacting of the convolutions which would cause degradation in quality. The spacer itself contacts the convolutions in small areas which are spaced across the sufficiently long and wide areas of the convolutions sufficiently closely to prevent such bending .or collapsing, but sufficiently widely not to interfere with the action of the treating gas on the convolutions of the strip in the open coil. A wide range of such spacings is possible. The spacer thus acts as a structural element of the open coil, not only in spacing the individual convolutions but also as an internal support for the open coil as a whole.

The thickness of the spacing element and of the members making it is largely dependent on the width and thickness of the strip metal to be wound into an open coil. In general, to permit as large a length of strip as possible to be heated in a given treating furnace, the spacer should be as thin as possible consistent with the function of maintaining adequate space between the convolutions of the open coil of strip to permit essentially complete access of the desired volume of treating gas to all portions of the strip while preventing bending or collapsing of the convolutions relative to adjacent convolutions that could degrade quality. A spacer of the type shown in FIGS. 1 and 2 having members 13 spaced about 2 inches apart and members 14 about 2% inches apart has been successfully used.

The invention also makes possible tighter winding in open coils of metal strips than would otherwise be possible. And this also aids in maintaining the shapes of the convolutions and coil during the heating.

As previously noted, the invention provides particular benefits when used with metal strips about 0.003 inch to about 0.035 inch thick and especially about 0.008 inch to about 0.035 inch thick, and from about 18 inches to about 72 inches wide, at treating temperatures ranging from about ll00F. to about 1750F. if the strip is steel, depending on the nature of the treatment to be applied and the composition of the strip.

While the invention has been disclosed having particular advantage in the treatment of very thin metal strip. it may also be used to advantage with thicker strip.

It will also be understood that the invention may be applicable not only to annealing of metal strip, but also to modification of the chemical composition and metallurgical structure by treatment of an open coil in which the spacer band is present. Various modifications apparent to those skilled in the art, in addition to those indicated, may be made in the apparatus, methods and articles indicated above, and changes may be made with respect to the features disclosed, provided that the elements set forth in any of the following claims or the equivalents of such be employed.

What is claimed is:

1. In the process of heat treating metal strip in an open coil which comprises coiling metal strip into an open coil in which the convolutions of the strip in said coil are spaced to permit passage of treating gas therebetween, said strip being of such small thickness and of such substantial width relatively to said thickness that when said treating gas is passed between said convolutions of said open coil adjacent convolutions of said strip in said coil can bend, distort, or change form sufficiently to cause said convolutions to contact sufficiently to impair substantially the uniformity of treatment by said gas and the quality of the treated strip unless said adjacent convolutions are kept separated over a major portion of the width of said strip and thereafter during such heat treatment passing a treating gas between said spaced convolutions of said strip, the improvement which comprises winding the strip into a coil simultaneously with a longitudinal spacer so that the spacer is located between adjacent convolutions of the strip, the spacer comprising a band that is at least as wide as a major portion of the width of said strip, that longitudinally of said band is sufficiently flexible to be wound between the convolutions of said strip in said coil and transversely thereof is sufficiently wide and stiff to restrict the convolutions of the coil separated by said spacer band from bending transversely thereof substantially throughout at least a major portion of the width of the strip, said spacer band being formed of spaced substantially parallel elongated members extending transversely of said spacer band, and spaced elongated members extending generally longitudinally of said spacer band and connected to said members extending substantially transversely of said spacer band, said members being relatively laterally offset to permit adequate flow of said gas between adjacent convolutions of said coil transversely of said convolutions, and contacting and supporting said spaced convolutions at a plurality of locations sufficiently closely spaced essentially to prevent contact of adjacent convolutions with each other, and being free of sharp edges or protrusions that can harm the surfaces of said strip in said coil convolutions.

2. A process of heat treating an open coil of metal strip in which the convolutions of strip are spaced to permit passage of treating gas therebetween by a spacer band that is interwound between adjacent convolutions of said strip of said coil, said strip being of such small thickness and of such substantial width relatively to said thickness that when said strip is wound into an open coil having spaced convolutions between which said treating gas is passed adjacent convolutions of said strip in said coil can bend, distort, or change form sufficiently to cause said convolutions to contact sufficiently to impair substantially the uniformity of treatment by said gas and the quality of the treated strip unless said adjacent convolutions are kept separated over a major portion of the width of said strip, said spacer band being at least as wide as a major portion of the width of said strip and longitudinally thereof being sufficiently flexible to be wound between the convolutions of said coil and transversely thereof being sufficiently wide and stiff to restrict the convolutions of said coil from bending transversely thereof throughout at least a major portion of the width of said strip, said spacer band being formed of spaced substantially parallel elongated members extending substantially transversely of said spacer band, and spaced elongated members extending generally longitudinally of said spacer band and connected to said members extending substantially transversely of said spacer band, said members being relatively laterally offset so as to permit substantially unimpeded flow of gas between adjacent convolutions of said coil transversely of said convolutions, and contacting and supporting said spaced convolutions at a plurality of locations sufficiently closely spaced essentially to prevent contact of adjacent convolutions with each other, and being free of sharp edges or protrusions that can harm the surfaces of said strip in said coil convolutions, which process comprises subjecting the open coil to heat treatment during which treating gas is passed between said spaced convolutions of said strip in said open coil.

3. The process of claim 2 in which said spacer band is substantially as wide as said metal strip.

4. The process of claim 2 in which said spacer band acts as a structural support for the convolutions of said strip in said coil.

5. The process of claim 2 in which said substantially transversely extending elongated members are all on one side of said generally longitudinally extending elongated members.

6. The process of claim 2 in which in said spacer band said generally longitudinally extending elongated mambers connecting said spaced transverse elongated members are metal of generally flat helical configuration with spaced vertices connected to adjacent transverse members, each transverse member being in a loop formed by engaged vertices of two adjacent flattened helices, the portions of the helices between the generally transverse members being offset from said geneally transverse members.

Claims

1. IN THE PROCESS OF HEAT TREATING METAL STRIP IN AN OPEN COIL WHICH COMPRISES COILING METAL STRIP INTO AN OPEN COIL IN WHICH THE CONVOLUTIONS OF THE STRIP IN SAID COIL ARE SPACED TO PERMIT PASSAGE OF TREATING GAS THEREBETWEEN, SAID STRIP BEING OF SUCH SMALL THICKNESS AND OF SUCH SUBSTANTIAL WIDTH RELATIVELY TO SAID THICKNESS THAT WHEN SAID TREATING GAS IS PASSED BETWEEN SAID CONVOLUTIONS OF SAID OPEN COIL ADJACENT CONVOLUTIONS OF SAID STRIP IN SAID COIL CAN BEND, DISTORT, OR CHANGE FORM SUFFICIENTLY TO CAUSE SAID CONVOLUTIONS TO CONTACT SUFFICIENTLY TO IMPAIR SUBSTANTIALLY THE UNIFORMITY OF TREATMENT BY SAID GAS AND THE QUALITY OF THE TREATED STRIP UNLESS SAID ADJACENT CONVOLUTIONS ARE KEPT SEPARATED OVER A MAJOR PORTION OF THE WIDTH OF SAID STRIP AND THERAFTER DURING SUCH HEAT TREATMENT PASSING A TREATING GAS BETWEEN SAID SPACED CONVOLUTIONS OF SAID STRIP, THE IMPROVEMENT WHICH COMPRISES WINDING THE STRIP INTO A COIL SIMULTANEOUSLY WITH A LONGITUDINAL SPACER SO THAT THE SPACER IS LOCATED BETWEEN ADJACENT CONVOLUTIONS OF THE STRIP, THE SPACER COMPRISING A BAND THAT IS AT LEAST AS WIDE AS A MAJOR PORTION OF THE WIDTH OF SAID STRIP, THAT LONGITUDINALLY OF SAID BAND IS SUFFICIENTLY FLEXIBLE TO BE WOUND BETWEEN THE CONVOLUTIONS OF SAID STRIP IN SAID COIL AND TRANSVERSELY THEREOF IS SUFFICIENTLY WIDE AND STIFF TO RESTRICT THE CONVOLUTIONS OF THE COIL SEPARATED BY SAID SPACER BAND FROM BEING TRANSVERSELY THEREOF SUB-