US1890463A

US1890463A - Metal coated iron or steel article and method and apparatus for producing same

Info

Publication number: US1890463A
Application number: US527496A
Authority: US
Inventors: Joseph L Herman
Original assignee: KEYSTONE STEEL AND WIRE CO
Current assignee: KEYSTONE STEEL AND WIRE CO
Priority date: 1931-04-03
Filing date: 1931-04-03
Publication date: 1932-12-13
Anticipated expiration: 1949-12-13

Description

..L 9 w 8 w 1 .am m h. m s Z D N A E Dec. 13, 1932. HERMAN METAL COATED IRON OR STEEL ARTIC AND APPARATUS FOR PRODUCING SAME Filed April 5. 1931 ///flN /////u 0 ?u 'L ma/n Dec. 13, 1932. L. HERMAN 1,390,463

METAL COATED IRON OR STEEL ARTICLE AND METHOD AND APFARATUS FOR PRODUCING SAME Filed April 3. 1931 2 Sheets -Sheet 2 Patented na 3, 932

UNITED STATES .TOSEIE L.

PATENT OFFICE' Hmm, OF PEOBIA, ILLINOIB, ASSIGNOB nmen BTEEI: &i WM COMPANY, OF PEOBIA, ILLINOIS, A CORPOBATION OI ILLUOIS HETAL (2(')A.'.I.`Il?D IRON OB STEZEL ABTICLE AND IETEOD am AHABATUS !OB PBJODUCING SAME Application med a ril a, 1931. Serial n'a. muss.

This invention has reference to metal coated iron or steel articles and to the method and apparatus for producing the same.

The invention has for its principal object 5 the coating of an iron or steel article with zinc so that the resulting article, whether it be wire, strips or the like shall pcssess a zinc coating of uniform thickness throughout and if wire, circumferentially and long'tudinally thereof, which coating will withstand severe deforming without flaking or peeling.

The invention has for a further object to coat iron or steel articles with a uniform thickness of zinc coating throughout and to beat-treat the zinc coated article whereby to provide an effective bond between the z nc and the iron or steel base thereby allowing for severe deforming of the 'coated articles `without flaking or peeling; the method of heat treating employed inhibiting in part, if not wholly, the formation of zinc oxide on the surface of the zinc' coating during the hoat-treatment and also inhibiting to a considerable degree the formation of zinc oxide skimmings on the surface of the molten zinc at the point where the articles treated and coated leave the bath, both of which are undesirable.

Other and further objects will more fully appear from the following description.

That the invention may be more fully understood, reference is had to the accompanying drawings forming part of this description, illustrating a preferred embodiment of the invention, in which i Fi 1 is a side' elevation, on a greatly reduce scale, of a unit by which my invention ma bepractced;

ig. 2 is a vertical sectional view, on a much 40 larger scale, showing the details of construction, of the unit, and

Fig. 3 is a cross-section, in plan, as the same would appear if taken onthe line 3--3 Fig. 2.

Like characters 'of reference denote corre- 4 sponding parts throughout the figures.

The present invention has to do wth the improvement on the process or' method of coating and treating materials having an iron base, as disclosed by my Patent No. 1530548 dated Oct. 3, 1922; the metal-coated iron or steel article, as disclosed by my Patent No. 1,468,905, and the appa'atus for coating and treat ng metallic materials,- as disclosed by my Patent No. 1,580387 dated April 13, 1926.

My present invention has to do with a vertical hot tube, as distinguished from a horizontally disposed furnace; also the eliminaton of skimm ng devices, as well as wipers, wth the result that the zinc coating (especially on wire) remains undisturbed while in the molten or semi-molten state, with the result that the thickness of the solid zinc coating, v

on the finished wire, is very uniform, both diametrically and longitudnally. Furthermore, by submerging the lower end of the so called hot tube in the molten zinc, in the galvaniz n pan, ingress of air into the tube, at the sur ace of the zinc, is prevented. Such an arrangement not only inhibits partially the formation of zinc oxide, on the surface of the zinc coating during beat-treatment, but also `nhibits in degree the formation of zinc oxide skimnings on the surface of the molten zinc inside the hottube, both of which are undesirable.

In the drawings 1"`desig`nates a galvanizing pan, of the usual design and structure in which is carried the molten zinc a and through which' the material to be coated is moved. In the present instance the material illustrated as being coated and subsequently heat-treated is w're b, `although it is not intended by such disclosure to limit the in- Vention to the coating and heat-treating of wire as the apparatus employed may be made aclaptable to the coating and heat-treating of strip and other materials. Primarily, the invention is directed'to the zinc coating of materials having an iron or 'steel base, and the heat-treating of such coated materials.

is intended to remove the material which h as been coated with zine, there is located or bult I .up or suitably supported a vertical hot tube 2 and said hot tube and its associated elements are su ported by a preferably steel structure 3 and such structure 'preferably comprises the frame of upright beams 4 extending u from the floor or foundation 5 ,to a oint we l above the pan 1 and it is into this rame and between these uprights that the pan 1 extends, somewliat in the manner shown n Fig. 1. The upri hts are connected at their upper ends by a ead frame 6 and the said upri hts mediate their up r and lower ends an at a suitable pofnt a ve the pan 1 are connected by cross-frames 7, in turn jointed by other frame parts 8.

The vertical hot tube 2 is disposed in a vertical position within and in an axial osition in relation to the frame composed o the upright beams 4 and the

cross-connecting frame parts

7 and 8 with the lower end of the hot tube structure located and supported immediately above the pan 1, see Big. 2.

The structure constituting the vertical hot tube and the tube proper I prefer to be constituted of and arran d and assembled as follows: A body pre erably rectangularin cross-section is enclosed within a metallic casing 9 which comprises side and end walls, a bottom closure and a top closure, see Fig. 2 with the corners, bottom and angular portons suitably brac'ed and reinforced, as at 10, see Figs. 2 and 3. Disfiosed centrallywithin the enclosin wall, is t e tube 11, which rojects throug and below the lower wall o the casing and down into the zinc spelter a within the pan 1, see Fig. 2 and which also projects through and above the upper wall of said casing, see also Figs. 1 and 2. I prefer, as shown in Fig. 3, that the tube,11 be made of two tubes which shall be oblong or rectangular in cross section and arranged and disposed as shown in Fig. 2 and that each tube shall comprise u per and lower joined sections 12 and 13. T e up r sections are preferably of soft steel or lie material and the lower sections of suitable heat resisting material. The

greater portion of the length of the tubes 11 are disposed within a vertical flue 14, the walls forming which being of a suitable refractory material 15 having lateral flues 16 therethrough at their upper ends which are in communication with other vertically disposed flues 17 disposed between the walls 15 and similar wa s 18 of suitable fractory material. The flues 17 at their lower ends communicate with anglarly disposed orlateral exhaust flues 19 which o i n out through the sides of the casing, see i 2. In addition to the refractory. walls or

inings

15 and 18 which form the flues 14 16, 17 and 19 and provide insulating mem ers within the casng, there is also provided other linings 20 of 'suitable insulating material, as a backing for the sides and ends of the casing andthe top thereof. The

walls

15 and 18 are separated b the s acers 21 of suitable refractory materia The ower ends of the flues 14 are chambered as at 22 for the introduction of a heating medium which circulates up through the flue 14, across through the\flues 16 and own through the flues 17 and out through the exhaust flues 19. e

I prefer to heat the hot tube proper by means of a gas flame and to beat-treat the coated material passing through the hot tube by radiation of 'heat from the tube. Burners 23 project a flame into the chambered end 'of the flue 14 and said burners are connected, respectively, with iping 24 connected with a suitab`.e source o supply. Any means may be provided to give access to the burners and if the life of the hot tube is too short, by reason of the direct contact of the flame, a baflie of somesuitable material ma be placed between the tube and burners. he tem erature andtemperature radient inside the ot tube would preferably e-800 F. to 1200 F. for the 'lower hot zone of the hot tube, preferably represented by' the tube section 13,' and 600 F. to 1000 F. for the upper hot zone, of the hot tube, preferably represented by the -tube section 12. ,These suggested temperatures are not limiting in any sense as they may be varied to meet all conditions of practice. I recommend a predetermined length of hot tube for a ven unit, which, however, may be varied in fl'erent units and for different materials, as of course will be understood.

In the practical application of the invention, I have elected to show a structure `de-' signed for use in connection with the zine coating of wire and the heat-treating of such material and while any commercial gauge diameter of wire is usable, for rate of travel of the wire through the zinc bath and hot tube, I recommend a range of speed of from thirteen (13) to fifty-two (52) 'feet per minute. The' wires b are passed through the molten zine a in the pan 1 and over preferably grooved rollers 25 which are submerged in the molten zinc and carried by a shaft 26 which passes out. of opposite walls of the Ban 1 and carried or supported by suitable earings. The wires are guided to and from the rollers 25, by suitable grooved guides 27 and 28 suitably supported submerged in the molten zine. The wires b are guided axially of and through the hot tube n the manner shown in Figs. 2 and 3 and on leaving the hot tube the wires are directed, preferably exposed, to the atmosphere to the upper end of the frame structure for the hot tube and over preferably grooved rollers 29, see 'Fig. 1, carried by a shaft suitably journaled on the head frame 6, and from the rollers 29 the coated and heat-treated wires -are directed to the blocks on the take-up frane I (not shown) by guiding rollers 31 carred.

by a referably downwardly inclined frame 32. he rollers 25 and 29 are preferably so arrange'd or located with respect to each other 'that the wire I leaving one set and passin bath vertically into and through the hot' tube or heat-treating chamber without touch ing the walls thereof (or any other ob ect) until the zinc coating on the wire has been well solidified. It should be ap arent, therefore, that by the use of the wt in described process, made possible by the structure disclosed, that the zinc coated wire does not come into contact with any rigid obiect either during emergence from the mo ten zinc (when the surface tension of the molten zinc coating causes it to adhere to the wire as a continuous liquid film of uniform thickness) or while it is passing through the hot tube to efiect heat-treatment of the zinc coating; or thereafter until the zinc coating has become completely solidified (after which the wire passes over the upper roller and from thence to the blocks on the take-up frane). Therefore, the zinc coating remans undisturbed while in the molten or semi-molten state, with the result that the thickness of the solid zinc coating on the finished wire is very uniform bothdiametrically and longitudnally. l urthermore, due to the fact that there is no zinc removed from the wire-by any contact of the coated wire, either during emergence from the bath or after leaving the bath, as for example with drip-bars, skimmers, wipes or the like, it is possible to get the maximum coating of zinc, consistent with the time that the wire is immersed in the zinc bath. i

I am familiar with most, if not all, processes and apparatus for zinc coating materials where efforts have been made to obtain uniforniity of coatings, including those of my own, to which reference has been made, but in all such processes and a paratus, with which I am familiar such uni ormity of coating thckness, both diametricall and longitudinall has been very diflicu t to attain; espec' y where the hot zinc coated wire is pulled over a drip-bar or skimmer as it emerges from the molten zinc bath, and is then carried horizontally through a, heattreater for beat-treatment of the zinc coating. The continuous dragging contact with a dripbar, ski'mner or the like causes a partial wiping of one side of the coated wire, which is only partially alleviated by the efiect of surface tension on the semi-molten coating during passage through the heat-treater. The

adhesive and bending qi'alities of the zinc coating fter application and beat-treatment as herein pointed out and by the use of the vertical hot tube is directly dependent u on the various factors to which I have hereto ore referred.

I have made mention of the submergence of the lower end of the hot tube in the molten zinc which will prevent ingress of air at the surface of the molten zinc, which inhibits partially, if not wholly, the formation of zinc oxide on the surface of the zinc coating during beat-treatment, as well as inhibits in degree the formation of zinc oxide skinmings on the surface of the molten zinc inside the hot tube, both of which are undesirable. In order to reduce the amount of surface oxidation of both the zinc bath and the zinc coating inside the hot tube, a suitable deoxidizer, as for example a thin layer of preferably granular charcoal 33 is used to coverthe surface of the molten zinc, in the lower end of the hot tube, see Fig. .2. The deoxidizer or charcoal is applied by dropping it into the hot tube at upper end thereof. This deoxidizer or`charcoal layer is not used in any sense as a wipe, but is used distinctly as a deoxidizer inside the lower end of the hot tube, particularly at-the surface of the molten zinc where the coated wire emerges into the hot tube atmosphere.

What I claim is 1. The herein described method of zinc coatin wire having an iron or steel base and imme ately following such coating heattreating the wire and coating while the coating is in a non-solidified condition, which consists in subjecting the wire to a bath of molten-zinc and removing the coated wire from the bath in a vertical direction and at the same tinie heat-treating such wire and coating, and in passing the coated wire through a deoxidizer at the point of emerg-- ence of the wire from the bath to the zone of beat-treatment, whereby to reduce the amount of surface oxidation of the zincbath at the surface of the molten zinc where the wire emerges therefrom and also within the heat-treating zone. v

2. The herein described method of zinc coating wire having an iron or steel base and immediately following such coating heattreating the wire and coating while the coating is in a non-solidified condition, which consists in subjecting the wire to a bath of molten-zinc and removing the coated wire from the bath in a vertical direction' and `at the same time heat-treating such wire and coating, and in passing the coated wire through' a thin layer of granular charcoal at the point of emergence of the wire from the bath to the zone of beat-treatment, whereby to reduce the amount of surface oxidation of the zinc bath at the surface of the molten zincwhere the wire emerges therefrom and also within *the heat-treatin zone.

8. In an apparatus of t e character described, in combination, a galvanzing pan for use with a bath' of molten-zine, means for diverting material subjected to the bath mto a vertical ath of travel as such material leaves the ath, a structure supported a vertical position above the pan 'at the pont where the material emerges from sad pan, such structure characterized by having a een` tral vertical heating flue andspaced vertical exhaust flues on opposite sides thereof in communication with said central flue at their upper ends and with exhaust outlets at their lower ends, an imperforate hot tube disposed in vertical osition in said central flue through which t e coated material is carried and having its lower end projecting throu h the structure and being submerged in the ath of molten zinc, means to guide the material from the pan and through the tube so as to prevent the material and coating from coming into contact with any object during emergence of the material from the bath and through the tube and until the coating has become substantially solidified, and means for heating the tube through heat inlets at the lower end of said central flue and in turn through radiation of the heat from the tube heat-treating the material and coating as it is carried through the tube.

4. In an apparatus of the character described, in combination, a galvanizing pan for use with a bath of molten-Zinc, means for diverting material subjected to the bath into a vertical ath of travel as such material leaves the ath, a structure supported in a vertical .position above the pan at the point where the material emerges from said pan, such structure characterized by having a central vertical heating flue and spaced vertical exhaust flues on' opposite sides thereof in communication with said central flue at their upper ends and with exhaust outlets at their lower ends, an imperforate hot tube d'isposed in vertical position in said central flue through which the coated material is carried and having its lower end projecting through the structure and being submerged in the bath of molten zinc, means to guide the material from the pan and through the tube so as to prevent the material and coating from coming into contact with anv object during emergence of the material from the bath and through the tube and until the coating` becomes substantially solidified, means for heating the tube through heat inlets at the lower end of said central flue and in turn through radiation of the he'at from the tube heat-treating the material "and coating as it is carried through the tube, and a deoxiding material on the surface of the bath within the tube, where the tube is submerged in the bath, to reduce the amount of surface oxidation of both the zine bath and the coating where the `for diverting material subjected to the bath into a vertical ath of travel as such material leaves the ath, a structure supported in a vertical position above the pan at the point where t e material emerges from said pan, such structurecharacterized by havin a central vertical heating flue and space vertical exhaust flues on o posite sides thereof in communication witli said central flue at their upper ends and with exhaust outlets at ther lower ends. an imperforate hot tube disposed in vertical position in said central flue through which the coated material is carried and having its lower end project ing through the structure and being submerged in the bath of molten zine, said tube consisting of joined aligned vertical sections, certain of which are of heat resisting material and certain others being of the consistency of soft steel, means to guide the material from the pan and through the tube to prevent the material and coating from commg into contact with any object durin energence of the material from the bath an 'through the tube and until the coating has become substantially solidified, and means for heating the tube through heatinlets at the lower end of said central flue and in turn through radiation of the heat from the tube heat-treating the material and coating it as it is carried through the tube.

6. In an apparatus of the character described, in combination, a; galvanizing pan for'use with a bath of molten-zine, means for diverting material subjected to the bath into'a vertical path of travel as such material leaves the bath, a structure supported in a verticalposition above the pan 'at the point where the material emerges from said' pan, such structure characterized by having a central vertical heating flue and spaced vertical exhaust flues on opposite sides thereof in communication with said central flue at their upper ends and with exhaust outlets at their lower ends, an imperforate hot tube disposed in vertical position in said central flue through which the coated material is carried and having its lower end projecting through the structure and being submerged in the bath of molten zinc, said tube consisting 'of Joined aligned vertical sections, certain of which are of heat resisting material and certain others being of the consistency of soft steel, means to guide the material from` the pan and through the tubeas to pre-j.

vent the material and coating from coming into contact with anv obiect during einer-g ence of the' material from the. bath and through the tube and' until the coating. be-

lll

comes substantially solidified. means for heating the tube through heat inlets at the lower end of said central flue and in turn through radiation of the heat from the tube heat-treating the material and coating asjt is carried through the tube, and a deoxidizing material on the surface of the bath within the tube, where the tube is submerged in the bath, to reduce the amount of surface oxidaton of both the zinc bath and the coating where the coated material emerges into the' atmosphere of the tube from such bath.

J OSEPH L. HERMAN.