US3205086A

US3205086A - Method and apparatus for continuous vacuum metal coating of metal strip

Info

Publication number: US3205086A
Application number: US6674A
Authority: US
Inventors: Robert M Brick; Curtis E Maier
Original assignee: Continental Can Co Inc
Current assignee: Continental Can Co Inc
Priority date: 1960-02-04
Filing date: 1960-02-04
Publication date: 1965-09-07
Anticipated expiration: 1982-09-07

Description

Sept. 7, 1965 R. M. BRICK ETAL METHOD AND APPARATUS FOR CONTINUOUS .ACUUM METAL COATING OF METAL STRIP 2 Sheets-Sheet l Filed Feb. 4, 1960 Sept 7, 1965 R. M. BRICK ETAL 3,205,086

METHOD AND APPARATUS FOR CONTINUOUS VACUUM METAL COATING OF METAL STRIP Filed Feb. 4, 1960 2 Sheets-Sheet 2 United States Patent O '3,205,086 METHOD A'ND APPARATUS FOR CONTINUOUS VACUUM METAL COATING '0F NETAL STRIP Robert M. Brick, Hinsdale, and Curtis E. Maier, Riverside, Ill., assignors t Continental Can Company, Inc.,

New York, N .Y., a corporation of New Yori:

Filed Feb. 4, 1960, Ser. No. 6,674 v 24 Claims. (Cl. 117-14) This invention relates to the application o-f coatings on strip and sheet material through the vacuum deposition of metal thereon from metal vapors, and is primarily directed to a method and apparatus for feeding strip and sheet material through a coating apparatus.

At the present time, it is common in the art of vacuum metallizing to coat with met-al from a vapor source onto =many exible substrates lby what is commonly referred to as a continuous batch process. In this type of process, a coil of the subst-rate is placed on a pay-olf stand, then it is threaded over .rolls carrying it over the vapor source or sources, `and finally onto a recoller roll, a-ll of the above equipment being enclosed in a chamber designed to be capable of withstanding high internal vacuum. The coating unit is then closed, evacuated to the proper vacuum of about 1 micron, and then the vapor sources are activated while the substrate is carried over the vapor sources from the pay-off stand to the recoiler. After one coil is coated, the vacuum is broken, air admitted, the coil of coated substrate is removed, and a new coil of uncoated substrate is placed on the .pay-ott stand to start the batch cycle again. This continuous batch process is not economic for large quantities because of the relatively great amount of non-productive ldown time required in the removing of the coil of coated substrate, placing another coil of uncoated substrate on the pay-oli stand, and then re-evacuating the coating unit to requisite very high vacuum.

Accord-ing to the instant invention, it is proposed to pr-ovide a complete production line with the prod-uct of such a line -being a continuously coated strip of a substrate material, such as steel, in any desired width, for example, a 36 inch wide stri-p, and Kof any desired guage within the general range `of 0.002 inch to 0.125 inch, with a met-allized coating, such as aluminum, having a thickness within the potential ranges of vacuum metallized coatings, 0.000002 inch 'to 0.00020 inch, and do so at commercially feasible speeds of 200 to 1,000 feet per minute, giving a product with a bright, adherent and corrosion resistant aluminum coating.

Accordingly, it is an object of the invention to prOu vide a continuously available supply of substrate for feeding through -a vacuum depositing apparatus, the substr-ate being in the form of a continuous strip which may be continuously fed through the coating apparatus at the `desired demand rate, thereby eliminating the periodic shut down of the coating apparatus as is required with substrates of limited lengths in the continuous batch method 'and equipment.

Another object of the invention is to provide in conjunction with an apparatus for cleaning metal substrate and applying a metal coating through a vacuum met-al depositing process an Iapparatus for joining coils of thin metal stock in strip form into a continuous strip for the continuous feeding thereof through a cleaning and vacuum depositiong metal coating apparatus at the demand rate of the cleaning and coating apparatus, the coil joining apparatus including a looping tower for retaining an avail- -able supply of metal stock to be fed t-o the cleaning and coating lapparatus during the time interval required to place a new coil `of metal stock into place and to join the `lead-ing end of the new coil to the trailing end of the prior coil, and a welding mechanism for joining trailing and leading ends lof coils.

Still another object of the invention is to provide an :apparatus for joining coils of metal stock into a continuous strip for feeding to an apparatus for metal coating the strip through a vacuum depositing process, the joining apparatus including means for supporting a coil of metal stock for unreel-ing, a shear aligned with the coil s-upport for cutting ott trailing and leading end portions of metal stock to assure the matching of ends of coils to be joined, a joint Welder aligned with the coil support and the shear for welding together matching ends of coils of :metal stock, and a weld grinder aligned .with the i joint Welder to grind the joint between adjacent coils to the thickness of the metal stock lof the coils to prevent interference with seals of the coating apparatus receiving the metal stock.

A further object of the invention is to provide a continuously operating production l-ine for the coating of sur- `faces of strip material in which the coating apparatus includes a plurality of metal vaporizers for the vacuum rmetal'lization of the strip on opposite surfaces thereof, and a Ispare metal vaponizer for each active vaporizer whereby shut down of the production line due to the failure or necessity for replacement of a vaporizer is eliminated.

Yet another object o-f the invention is to provide in a continuously operating production line for the metallizing of strips, -a coating apparatus having separate vaporizers for coating opposite surfaces of strips, the total coating capacity lof vaporizers for one surface of -a strip being greater than the total capacity of vaporizers for the other vsurface of the strip wherein a differentially coated strip is formed.

A still further object of the invention is to provide a novel method of continuously vacuum aluminum coating strip material wherein the stnip material is provided in individual coi-ls, the leading and trailing ends of adjacent coils of strip material being welded together to form `a continuous strip which is provided to a continuously operating coating apparatus, at the demand rate thereof, after which the coated strips are again wound in coils and sheared from the continuous strip, the continuous strip passing through a looping tower and being temporarily stored during the changing of coils between recoiling operations.

Still another object of the invention is to provide a novel apparatus and method for continuously vacuum metal coating metal strip material wherein the strip material is provided in individual coils, the leading and trailing ends of adjacent coils of strip material being welded together to form a continuous strip which is supplied to Ia continuously operating coating `apparatus at the operat- .ing rate thereof, after which the coated strip material is cut into individual lsheets and passed through a classifying -apparatus for detecting and removing sheets having pin hoi-e defects therein.

With these and other objects in view as will appear in the course of the following description and claims, an illustrative embodiment is shown on the accompanying drawings which show the successive steps in conventionalized form.

In the drawings:

FIGURES l and lA are schematic elevational views showing the general arrangements of the components of the production line.

FIGURE 2 is an enlarged elevational view showing the details of one of the metal vaporizers.

FIGURE 3 is an enlarged sectional view showing the details of a typical vacuum seal.

FIGURE 4 is a schematic elevational view of a modified tail end of the production line of FIGURES 1 and lA, and shows the details of a sheet cutter and a sheet classifier.

ln the drawing, a steel strip S is supplied in the form of coils C which are individually mounted on a pay-olf stand to facilitate the unwinding of the strip S, the pay-off stand 5 having an arbor 6 receiving the coil C. After the strip S is unwound from the coil C, it f1rst passes through a shear, generally referred to by the numeral 7, which is aligned with the pay-olf stand 5. The shear 7, in its simplest form, includes a fixed anvil 8 and a vertically movable blade 9 which cooperates with the anvil to cut off the trailing end of the strip S of one coil C and the leading end of the strip S of another coil C in matching relation.

A joint Welder 10 is positioned adjacent `the shear 7 and receives the sheared trailing end and the shearcd leading end of a pair of strips S. The joint Welder 10 is preferably of an electric type and includes a pair of electrodes 11, 12 disposed in opposed relation above and below the path of travel of the strips S.

A butt weld is formed between the trailing end of the one strip S and the leading end of the second strip S, and in the formation thereof rough upset metal is disposed on opposite surfaces of the strips S which are now welded into one. In order to provide smooth surfaces for passage through vacuum seals to be described in detail hereinafter, a grinder, generally referred to by the numeral 13, is provided. The grinder 13 includes a pair of grinding wheels 14, 15 disposed in opposed relation to the opposite surfaces of the strip S. After the grinding operation has been completed, the strip S is for all purposes one uninterrupted strip.

It is the intention of the invention that the strip S be continuously supplied at the demand rate of the coating apparatus which will be described in detail hereinafter. After a strip S has been completely unwound from its coil C, it is necessary that movement of the trailing end of the strip S be discontinued until such time as another coil C may be placed on the mandrel 6 of the pay-off stand 5,y and the weld between the two strips S formed and ground. To make the continuous feed of the strip S to the coating apparatus possible under these conditions, a looping tower, generally referred to by the numeral 16, is provided. The looping tower 16 includes a frame 17 on which a fixed in-feed roll 18 and a fixed out-feed roll 19 are mounted in generally horizontal alignment. An upper roll support 20 is supported by the upper part of the frame 17, and a plurality of upper rolls 21 are conlnected to the upper roll support 20. A carriage 22 is mounted in a guideway 23 of the frame 17 for vertical movement and carries a lower roll support 24 for movement with the carriage 22 towards and away from the upper roll support 22. A plurality of lower rolls 25 are carried by the lower roll support 24; the lower rolls 25 being one less in number than the upper rolls 21 and stagi gered relative thereto. The strip S passes under the infeed roll 1S, up and over one of the upper rolls 21, back and forth between and around the upper rolls 21 and the lower rolls 25, and finally down from one of the upper rolls 21 and under the out-feed roll 19.

The trailing end portion of a strip S is held against movement into the looping tower 16 by a clamp unit, v

generally referred to by the numeral 26, mounted on the frame 17 in advance of the looping tower 16. The clamp vunit 26 includes a fixed clamp member 27, which is ,the strip S therebetween when the liuid motor 30 is actuated, thus preventing the pulling of the trailing end of the strip S into the looping tower 16.

rl`he strip S, the surface of which is assumed to be only moderately cleaned, passes from the out-feed roll 19 into a cleaning apparatus which includes a tank 32 which illustratively contains an aqueous solution 33 of an alkali such as alkaline orthosilicate or alkline phosphte, with an inhibitor and a wetting agent, such as that prepared with the product known in commerce by the trademark Orthosil. A desirable concentration is 4 ounces per gallon at 170 to 190 F. The strip S preferably is subjected to electrolysis in the bath solution 33, e.g., as the cathode between a pair of spaced plates 34. The plates 34 are connected by conductors 35 to a generator G.

From the tank 32, the strip S passes into a scrubbing unit. The scrubbing unit includes a tank 36 in which rotating upper and lower scrubbing brushes 37 are positioned above and below the strip S, respectively, for removing surface residues. Cold water jets 38 are directed onto the strip S, both from above and below, in advance of and rearwardly of the scrubbing brushes 37.

From the scrubbing tank 36, the strip S may be passed into a tank 39 containing an acid bath 40. This bath illustratively is a warm 4 percent aqueous solution of sulfuric acid, containing about 1/2 percent of yellow phosphorus prepared in carbon disulfide solution and thoroughly mixed therein. The tank 39 has a pair of spaced plates 41 therein between which the strip S passes. The plates 41 are connected by conductors 42 to a generator G, so that the steel strip is cathodic. A low-voltage, low-amperage current of about 1/2 ampere per square inch of strip surface is employed. A desirable temperature of the electrolyte is 150 F.

In practice, low carbon steel may have a content of 0.05 to 0.10 part per million of hydrogen. The cathodic charging of low carbon steel in an acid bath can store up to about 3 parts per million of hydrogen therein. When the yellow phosphorus is present in the acid bath, the cathodic charging can effect storage of up to l4 parts per million. The expression of parts per million refers to parts by weight: that is, one part per million means that 0.0001 percent by weight of hydrogen is present in the ferrous material. This hydrogen storage occurs within the atomic lattice structure of the ferrous body. The accepted value of solubility of hydrogen in the ferrous metal is less than 0.01 part per million at room temperature. Cathodic treatment with the instant acid bath with phosphorus results in hydrogen, nascent form, being released at the surfaces of the strip S and the storing of the hydrogen within the strip.

The strip S next passes through a cold water rinse 43 and then through a hot water rinse 44. The strip S next passes through a hot air drier 45 which includes a pair of hot air ducts 46 disposed above and below the strip and directing hot air upon the surfaces of the strip to dry the same.

After drying, the strip S moves into engagement with an in-feed drive unit, generally referred to by the numeral 47. The in-feed drive unit includes a base 48 having an upstanding shaft 49 on which a frame 50 is mounted for limited rotation. A pair of driven wrap-around rolls 51 are supported by the frame for movement therewith. The rotation of the frame 50 is controlled by a gear drive 52 ,and a reduction gear unit 53 driven by an electric motor 54. In this manner, alignment of the strip S may be controlled by a pair of control devices 55 for the electric motor 54, which is of the reversible type, the control devices 55 being positioned adjacent the edges of the strip S and engaged thereby when the strip becomes misaligned.

A vacuum chamber, generally referred to by the numeral 56, is disposed next to the in-feed drive unit 47. The vacuum chamber 56 includes a housing 57 which has' a pair of end walls 58, and a pair of partition walls 59, dividing the housing into compartments 60, 61, and 62.

The compartment 60 is in the form of an antechamber and the entrance thereinto is sealed by a vacuum seal 63. The compartment 60 is evacuated through a Vacuum pump line 64 which is connected to a conventional type of vacuum pump (not shown), the pressure within the chamber 60 is reduced to from 1 to 20 mm. of mercury from the normal atmospheric pressure of 760 mm. of mercury.

A second vacuum seal 65 is disposed at the entrance to the compartment 61 which is a heater compartment. A vacuum pump line 66 for a high capacity booster pump is connected to the compartments 61 and 62, and the pressure therein is reduced down to from 0.005 to 0.020 millimeter of mercury (5 to 20 microns). A third vacuum seal 67 is disposed at the entrance to the compartment 62. The vacuum seals 63, 65 and 67 may be identical, and a typical one thereof will be described in detail hereinafter.

The strip S, in passing through the heater compartment 61, is heated, illustratively by induction coils 68 supplied with high frequency current from conventional supplies. The strip S is thereby heated to 400 to 1,200 degrees F., for example, wherewith the rate of hydrogen withdrawal is increased manyfold. Although the solubility factor of hydrogen in steel is also increased, it remains below one part per million at 1,000 degrees F., as compared to 2 to 12 or more parts per million, which may be stored in the ferrous base. The hydrogen therefore is withdrawn at the surface of the strip S, and diffuses from the interior of the strip body rapidly and in proportion as the surface layers are stripped of excess hydrogen. This hydrogen is released at the surface of the strip largely in atomic or nascent form, and is highly reactive as compared to the prior employments of super-atmospheric pressures of molecular hydrogen around the ferrous base. As the atomic hydrogen passes any superficial surface oxide, it displaces the oxygen therefrom and Water vapor is formed and expelled from the strip surface by subsequent hydrogen atoms.

In practice, the pressure in the compartment 61 is held at to 50 microns, with the vacuum pump line 64 removing Water vapor and hydrogen. Preferably, the rate of travel and the time of vacuum heating exposure is such that the stored hydrogen is reduced to a fraction of its initial value. The pressures specified for compartment 61 are more economical than maintenance of pressures of l micron or below which are requisite for good vacuum metallizing of the cleaned strip.

After passing through the seal 67, the surface of the strip S has been cleaned sufficiently to obtain proper bonding of metal vapor to the strip surface. Due to the heatting of the strip S Within the heater compartment 61, the temperature of the strip S may be above the temperature for restricting alloying of aluminum with the steel strip S and it may be necessary to cool the strip S back to the temperature of 200 to 600 degrees F. required to minimize alloying and obtain bonding depending on the time factor and natural radiation heat losses. This may be accomplished by either forming the seal 67 as a cooling seal, as is illustrated, or by providing separate cooling apparatus, such as by use of Water cooled rollers (not shown), within the compartment 62 for cooling the strip S.

Although it may be necessary to cool the trip S when coating with aluminum, it may be necessary to heat the strip S when other metals are being deposited on the strip S. For example, induction heating coils 69, supplied With high frequency current from a conventional supply 74), may be required in the compartment 62 to bring the strip `S back to a bonding temperature of 400 to 1,000 degrees F., depending on the time factor and natural radiation heat losses, When the metal being deposited is titanium.

A metallizing chamber 71 is disposed next to the compartment 62 and is separated therefrom by a slit seal 72. The pressure within the metallizing chamber 71 is maintained at no more than 1 micron through an evacuation connection '73 to a group of diffusion, booster and backup pumps, as known in the art. The pressure within the preceding compartment 62 being approximately 20 microns, and under this low pressure differential and at these low pressures where gas molecule free paths are very long, a simple slit is adequate to separate the compartment 62 from the chamber 71 and minimize gas How from one into the other.

Within the metallizing chamber 71, the strip S passes around a plurality of guide rolls 74 arranged to define a rectilinear generally S-shaped path. As the strip S passes along a rst and upper horizontal run, it passes between and is exposed to aluminum or other metal vapor from a pair of opposed active vaporizers disposed above and below the strip S and generally referred to by the numeral 75. Thus, vapor may be deposited on both surfaces of the strip when they are within the desired temperature range. In addition to the active vaporizers 75, there are alternative vaporizers, generally referred to by the numeral 76, which can be made active when it becomes necessary to remove and renew the vaporizers 75. Thus conceptually, the line need not be stopped upon erosion, corrosion, or burn-out of any vaporizer.

After a thin coating of aluminum has been deposited on opposite surfaces of the strip S under optimum conditions, additional active vaporizers 75 may be used in any desired number to build up the initially bonded thin coatings to the desired thickness. In the drawing, an additional active vaporizer 7S is shown coating the lower surface of the strip S, after which the strip is reversed in travel direction and two additional active vaporizers 75 deposit aluminum or other metal vapor on what was originally the upper strip surface. Each of the additional vaporizers 75 will have a corresponding spare vaporizer 76. Not only may the total number of vaporizers be varied to vary total thickness of aluminum coating, but also the number of vaporizers coating one strip surface may be greater than those coating the opposite strip surface, thereby obtaining What may be called a differentially coated strip. For example, one surface may have a coating of 0.000015 inch thickness and the opposite surface a coating of 0.000030 inch thickness.

A

typical vaporizer

75, 76, as shown in FIGURE 2, includes a sleeve-like housing 77 having a dispensing opening through which the aluminum vapor must flow to escape. Within the housing 77, a vaporizing element 78 extends between a pair of bus bars 79, S0 and is resistively heated by current from the bus bars. The coating metal can be supplied to the heated vaporizing element 78 in the form of a wire 81 which melts upon striking the surface of the heated element 78 and the molten metal evaporated at the low pressure, so that its vapor deposits on the strip S.

' In order to facilitate the repair or replacement of components of the

vaporizers

75, 76, the housing 77 may, for example, be rotatably mounted in sealed relation within a fixed second sleeve-like housing 77 which has a permanently upwardly directed dispensing opening. When the Vaporizer 75, '76 is inactive, the dispensing openings of the

housings

77, 77 are out of alignment, and access to the interior of the housing 77 may be had through one end thereof Without affecting the pressure Within the metallizing chamber 71. The housings 77, 77' will, of course, be provided with suitable ends to prevent leakage of air into the metallizing chamber 71 when the dispensing openings of the housings 77, 77' are aligned.

Although the drawing shows the vaporizers in horizontal planes and the strip S moving in horizontal planes during the coating operation, this is not intended to be restrictive. The strip may travel in a vertical direction with slanted vaporizers on both sides of the strip coating and simultaneously coating both surfaces thereof. Here again, the number of vaporizers for the different strip surfaces being coated may be varied to obtain a differentially coated strip. A differentially coated strip may also be obtained by means other than varying the number of Vaporizers. For example, smaller vaporizers may be provided for one surface of the strip, or the vaporizers for one surface may be operated at a lower evaporative rate. However, the use of different numbers of vaporizers will normally provide the greatest operating flexibility.

When leaving the metallizing chamber 71, the strip S pasess through a second slot seal 82 into a chamber 83 wherein the pressure is maintained at approximately microns by an evacuation connection S4. Water cooled plates 85 are mounted within the chamber 33 adjacent the surfaces of the strip S for cooling the same.

The strip S next enters a chamber 86 through a seal S7. The seal 87 may be of the same type as the

seals

63, 65 and 67, although it may be desirable to water cool the housing thereof. The pressure within the chamber 86 is maintained in the vicinity of l to 20 mm. of mercury through an evacuation connection 88. The strip S then passes to the atmosphere through a seal 89 which is identical to the

seals

63, 65 and 67.

After leaving the seal 89, the strip S passes to a tension stand 90. The tension stand 90 includes a pair of driven wrap-around rolls 91 about which the strip S passes. The wrap-around rolls 91 are driven at a speed in proportion to the speed of the wrap-around rolls 51 to maintain the desired constant tension in the strip, and thereby assure optimum tracking, eliminating sidewise weaving other than that weave unavoidable from the camber in commercially rolled strips.

The strip S then enters a looping tower 92 which may be identical with the looping tower 16. However, while the looping tower 16 is normally loaded to provide a strip supply while another coil C is being joined to the strip S, the looping tower 92 is normally empty and available for the temporary storage of a quantity of the coated strip S.

A speed-up strip drive stand 93 is disposed adjacent the looping tower 92 and includes a pair of wrap-around rolls 94 about which the coated strip S passes. A shear 95, similar to shear 7, is disposed next to the speed-up strip drive stand for cutting the coated strip into individual coils C'. The coils C are wound on a mandrel 96 of a multiple mandrel coil winding stand 97,`which is the terminal component of the production line. The speed-up strip drive stand 93 drives the coated strip S at a speed faster than the line speed, thus emptying the looping stand 92 during the winding of a coil C' of the coated strip S and rendering the looping stand 92 available for storage of additional strip during the changing of coils C'.

A typical seal, which for purposes of identication will be considered to be the seal 63, is 3. The seal 63 includes a housing 98 having a strip passage 99 extending longitudinally therethrough. Opposed pairs of pockets 100 are formed in the housing 99 on opposite sides of the strip passage 99 and opening thereinto. A roller bearing block 101 is disposed in each of the cavities 100 and supports a roller 162. The rollers 102 engage opposite surfaces of the strip S passing therebetween and forni a seal therewith, one roller of each pair of rollers 102, together with its associated block 101, being resiliently urged towards the strip passage 99 and the strip S disposed therein by a spring 103.

The vacuum seals 63, as well as other equivalent Seal structures, would be scarred or marred and their sealing efficiency diminished if the weld joint were not ground, as previously set forth hereinabove, or otherwise smoothed and reduced to a thickness not much exceeding the thickness of the normal strip S. Also, at this time, it is again pointed out that it is essential to shear in carefully aligned relationship the strip portions to be joined together in order that the continuous strip S be straight throughout to assure tracking of the strip S through the vacuum chamber, and thereby avoid sidewise motion which would otherwise jam the entire operation.

Reference is now made to FIGURE 4, wherein the deiuustrared in FIGURE tails of a modified tail end of the production line of FIG- URES 1 and 1A are illustrated. In this form of production line, the coated strip S passes from the tension stand 90 to a sheet cutter, generally referred to by the numeral 110. The sheet cutter is illustratively shown as including a pair of rolls 111, 112 having mating offset portions for effecting the desired shearing action. The diameters of the rolls 111, 112 may be varied to vary the lengths of the sheets cut from the continuous strip S. The sheets are referred to by the numeral 113.

After the sheets 113 are formed by the action of the sheet cutter 11d, the sheets move along a suitable guide 114 to a sheet classifier, generally referred to by the numeral 115. Any suitable type of conveyance means may be provided for so moving the sheets. The sheet classiiier 115 is utilized to detect pin holes which may exist in the sheets 113 and to remove defective sheets.

The sheet classifier basically includes a bright light source 116 on one side of the path of the sheets 113, and photoelectric cell units 117 on the other side of the path. When a sheet 113 moves between the light source 116 and the photoelectric cell units 117 and there is a pin hole in the sheet, light through the pin hole activates a photomultiplier tube of one of the photoelectric cell units 117. Illustratively, the guide 114 includes a movable section 118 which may be tilted to reject a defective sheet 113. The guide section 118 may be positioned by an electrically operated device 119 which is connected to the photoelectric cell units 117 and the operation of the device 119 controlled thereby. The circuit for the device 119 may include spaced switches 120 which are both closed only when the sheet 113 to be inspected is aligned with the light source 116 and the photoelectric cell units 117, thereby preventing the operation of the device 119 due to the spacing between adjacent ones of the sheets 113.

With a fast moving line, when the device 119 is actuated, as many as ve or six sheets 113 will be directed from the line by the movement of the guide section 118. Accordingly, a manual inspection of the discarded sheets 113 may be required to separate the defective one.

The foregoing has been specically directed to the application of aluminum coatings on steel substrates. However, the invention is not intended to be so limited. In addition to aluminum, the fourth period transition metals (Ti, V, Cr, Mn, Fe, Co, Ni) may be employed as the coating metals. The coatings on the opposite side of the substrate need not be of the same metal, but may be of two different metals of the aforementioned metals, and the two different metal coatings may be of different thicknesses. For example, a metal coated metal strip of particular potential utility to can makers would be a ferrous substrate having an easily solderable metal on the surface which would be the outside of a can and a protective metal on the surface which would be the inside of the can. A thin coating of cadmium on the outside would give easy solderability and excellent resistance to rusting whereas titanium may be used on the inside for corrosion resistance to foods. Also, the complete process may be employed in conjunction with metal substrates, other than ferrous substrates, which are capable of hydrogen absorption.

Further, other substrates that do not absorb hydrogen may be coated with metals in accordance with the disclosed process by eliminating the step of charging the substrate with hydrogen in the cleaning operation prior to the vacuum metallizing operation.

In considering the use of the described apparatus for the application of coatings of diiferent metals, it is pointed out that the temperature of the substrate at the time the metal vapor of the coating metal strikes the substrate will vary depending upon the coating metal. In some instances, it will be necessary to cool the strip S as it enters the chamber, and in other instances, it will be necessary to heat the strip S. When coating a steel substrate with aluminum, the temperature of the strip S should be between 300 degrees and 500 degrees F. when the aluminum vapor hits it. When this temperature range is maintained, the resulting coating is less porous, somewhat coarser in grain size and noticeably more resist-ant to corrosion than if the steel strip is cold, i.e., below 150 degrees F. On the other hand, if the steel strip is too hot, e.g., 700 degrecs to 900 degrees F., some detectible brittle alloy, Fe2Al5, is formed at the iron-aluminum interface and this is detrimental to fabrication of the coated strip. On the other hand, when coating with titanium and chromium, it has been found necessary to have the steel strip at temperatures of 700 degrees to 900 degrees F. at the time the metal vapor hits the strip if an adherent coating is to be obtained.

The illustrative embodiments are not restrictive, and the invention may be practiced in many Ways Within the scope of the appended claims.

We claim:

1. A method of continuous metal coating a metal strip comprising the steps of providing the strip material in individual coils, transversely shearing the trailing end of a lirst coil and the leading end of a second coil at substantially the same angle to assure the mating of the ends of the coils, welding together the strip material of the individual coils in end-to-end relation to form a continuous strip, finishing the surfaces of the continuous strip in the Weld area to form a joint having smooth sealable surfaces and a thickness substantially less than the combined thickness of the two joined strip material, storing certain of the continuous strip to assure a continuous supply of strip material during the time required for the addition of another coil of strip material to the continuous strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension on the strip While Within the vacuum chamber to facilitate tracking along a predetermined path Within the vacuum chamber, heating the strip to remove gases and oxides from the strip, thermally treating the strip to maintain the strip at the desired coating temperature, depositing metal on opposite surfaces of the strip from sources of metal vapor by condensation of metal vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, rewinding the coated strip material in coil form, together with the storing of portions of the coated strip material as it passes out of the vacuum chamber during the removal of a coil and feeding the coated strip material during the Winding of a coil at a faster rate than the feed rate through the vacuum chamber to substantially deplete the stored coated strip material, and then cutting ot the individual coil.

2. `A method of continuous metal coating a metal strip comprising the steps of providing the strip material in individual coils, transversely shearing the trailing end of a rst coil and the leading end of a second coil at substantially the same angle to assure the mating of the ends of the coils, welding together the strip material of the individual coils in end-to-end relation to form a continuous strip, finishing the surfaces of the continuous strip in the Weld area to form a joint having smooth sealable surfaces and a thickness substantially less than the combined thickness of the two joined strip material, storing certain of the continuous strip to assure a continuous supply of strip material during the time required for the -addition of another coil of strip material to the continuous strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber 4and maintaining a tension on the strip While within the vacuum chamber to facilitate tracking along a predetermined path Within the vacuum chamber, heating the strip to remove gases and oxides from the strip, thermally treating the strip to maintain the strip at the desired coating temperature, depositing different metals 1t) on opposite surfaces of the strip from sources of metal vapor by condensation of metal vapor on the moving strip, passing the strip out of the Vacuum chamber through a seal, rewinding the coated strip material in coil form, together with the storing of portions of the coated strip material as it passes out of the vacuum chamber during the removal of a coil and feeding the coated strip material during the Winding of a coil at a faster rate than the feed rate through the vacuum chamber to substantially deplete the stored coated strip material, and then cutting olf the individual coil.

'3. A method of continuous metal coating a metal strip comprising the steps of providing the strip material in individual coils, transversely shearing the trailing end of a rst coil and the leading end of a second coil at substantially the same angle to assure the mating of the ends of the coils, Welding together the strip material of the individual coils in end-to-end relation to form a continu- Ious strip, finishing the surfaces of the continuous strip in the Weld area to form a joint having smooth sealable surfaces and a thickness substantially less than the combined thickness of the tWo joined strip material, storing certain of the continuous strip to assure a continuous supply of strip material during the time required for the addition of another coil of strip material to the continuous strip, passing the strip through an electrolytic apparatus -to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension on the strip while within the vacuum chamber to facilitate tracking along a predetermined path within the vacuum chamber, heating the strip to remove gases and oxides from the strip, thermally ltreating the strip to maintain the strip at the desired coating temperature, depositing metal coatings of different thickness on opposite surfaces of the strip from sources of metal vapor by condensation of metal vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, rewinding the coated stripmaterial in coil form, together with the storing 0f portions of the coated strip material as it passes out of the vacuum chamber during the removal of a coil and Ifeeding the coated strip 'material during the Winding of a coil at a faster rate than Ithe feed rate through the vacuum chamber to substantially deplete the stored coated strip material, and then cutting otf the individual coil.

4. A method of continuous aluminum coating a steel strip comprising the steps of providing the strip material in individual coils, transversely shearing the trailing end of a first coil and the leading end of a second coil at substantially the same angle to assure the mating of the ends of -the coils, welding together the strip material of the individual coils in end-to-end relation to form a continuous strip, tinishing the surfaces of the continuous strip in the Weld area to form a joint having smooth sealable surfaces and a thickness substantially less than the combined thickness of the two joined strip material, storing cer-tain of the continuous strip to assure a continuous supply -of strip material during the time required for the addition of another ooil of strip material to the continuous stril passing the strip through an electrolytic app-aratus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension 'on the strip while within the vacuum chamber to facilitate tracking along a predetermined path within the vacuum chamber, heating the strip to remove gases and oxides -from the strip, thermally treating the strip to maintain the strip at the desired coating temperature, depositing aluminum on one surface of the steel strip from a source of metal vapor by condensation of aluminum vapor on the moving strip, passing the strip out of the vacuum ychamber through a seal, rewinding the coated strip material in coil form, -together with the storing of portions of the coated strip material as it passes out of the vacuum chamber during the removal of a coil and feeding the coated strip material during the winding of a coil at a faster rate than the feed rate through the vacuum chamber to substantially deplete the stored coated strip material, and then cutting off the individual coil.

5. A method of continuous metal coating a metal strip comprising the steps .of providing the strip material in individual coils, transversely shearing the trailing end of a first coil and the leading end of a second coil at substantially the same angle to assure the mating of the ends of the coils, connecting together the strip material of the individual coils in end-to-end relation to form a continuous strip with a joint having smooth sealable surfaces and a thickness substantially less than the combined thickness of the two joined strip material, storing certain of the continuous strip to assure a continuous supply of strip material during the time required for the addition of another coil of strip material to the continuous strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension of the strip while within the vacuum chamber to facilitate tracking along a predetermined path within the vacuum chamber, heating the strip to remove gases and oxides from the strip, thermally treating the strip to maintain the strip at the -desired coating temperature, depositing metal on opposite surfaces of the strip from sources of metal vapor 1y condensation of metal vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, rewinding the coated strip material in coil form together with the storing of portions of the coated strip material as it passes out of the vacuum chamber during the removal of a coil and feeding the coated strip material during the winding of a coil at a faster rate than the feed rate through the vacuum chamber to substantially deplete the stored coated strip material, and then cutting off the individual coil.

6. A method of continuous metal coating a metal strip comprising the steps of providing a continuous metal strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaing a tension on the strip while `within the vacuum chamber to facilitate tracking along a predetermined path within the vacuum chamber, heating the strip to remove gases and oxides from the strip, thermally treating the strip to maintain the strip at the desired coating temperature, depositing metal on opposite surfaces of the strip from sources of metal vapor by condensation of metal vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, and cutting the coated strip into readily handleable units.

7. A method of continuous metal coating a meal strip comprising the steps of providing a continuous strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension on the strip While within the vacuum chamber to facilitate tracking along a predetermined path Within the vacuum chamber, heating the strip to remove gases and oxides from the strip, thermally treating the strip to maintain the strip at the desired coating temperature, depositing metal on ouposite surfaces of the strip from sources of metal vapor by condensation of metal vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, rewinding the coated strip material in coil form, together with the storing of portions of the coated strip material as it passes out of the vacuum chamber during the removal of a coil and feeding the coated strip material during the winding of a coil at a faster rate than the feed rate through the vacuum chamber to substantially deplete the stored coated strip material, and then cutting off the individual coil.

8. A method of continuous metal coating a metal strip comprising the steps of providing the strip material in individual coils, transversely shearing the trailing end of a first coil and the leading end of a second coil at substantially the same angle to assure the mating of the ends of the coils, welding together the strip material of the individual coils in end-to-end relation to form a continuous strip, finishing the surfaces of the continuous strip in the weld area to form a joint having smooth sealable surfaces and a thickness substantially less than the combined thickness of the two joined strip material, storing certain of the continuous strip to assure a continuous supply of strip material during the time required for the addition of another coil of strip material to the continuous strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension on the strip while Within the vacuum chamber to facilitate tracking along a predetermined path Within the vacuum chamber, heating the strip to remove gases and oxides from the strip, thermally treating the strip to maintain the strip at the desired coating temperature, depositing metal on opposite surfaces of the strip from sources of metal vapor by condensation of metal vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, and cutting the coated strip into a plurality of sheets as the coated strip continuously moves.

9. A method of continuous metal coating a metal strip comprising the steps of providing the strip material in individual coils, transversely shearing the trailing end of a first coil and the leading end of a second coil at substantially the same angle to assure the mating of the ends of the coils, welding together the strip material of the individual coils in end-toend relation to form a continuous strip, finishing the surfaces of the continuous strip in the Weld area to form a joint having smooth scalable surfaces and a thickness substantially less than the combined thickness of the two joined strip material, storing certain of the continuous strip to assure a continuous supply of strip material during the time required for the addition of another coil of strip material to the continuous strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension on the strip While Within the vacuum chamber to facilitate tracking along a predetermined path within the vacuum chamber, heating the strip to remove gases and oxides from the strip, thermally treating the strip to maintain the strip at the desired coating temperature, depositing metal on opposite surfaces of the strip from sources of metal vapor by condensation of metal vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, cutting off the coated strip into a plurality of sheets as the coated strip continuously moves, and passing the sheets through a classifying apparatus to remove defective ones of the sheets.

10. A method of continuous metal coating a metal strip comprising the steps of providing a continuous metal strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension on the strip while within the vaccum chamber to facilitate tracking along a predetermined path within the vacuum chamber, heating the strip to remove gases and oxides from the strip, depositing metal on the strip from a source of metal vapor by condensation of metal vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, and cutting the coated strip into a plurality of sheets as the coated strip continuously moves.

11. A method of continuous metal coating a metal strip comprising the steps of providing the strip material in individual coils, transversely shearing the trailing end of a first coil and the leading end of a second coil at substani3 ti'ally the same angle to assure the mating of the ends of the coils, connecting together the strip material of the indivdual coils in end-to-end relation to form a continuous strip with a joint having smooth sealable surfaces and a thickness substantially less than the combined thickness of lthe two joined strip material, storing certain of the continuous strip to assure a continuous supply of strip material during the time required for the addition of another coil of strip material to the continuous strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension on the strip while within the vacuum chamber to facilitate tracking along a predetermined path within the vacuum chamber, heating .the strip to remove gases and oxides from the strip, thermally treating the strip to maintain the strip at the desired coating temperature, depositing metal on opposite surfaces of the strip from sources of metal vapor by condensation of metal vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, and cutting the coated strip into a plurality of sheets as the coated strip continuously moves.

12. A method of continuous aluminum coating a steel strip comprising the steps of providing the strip material in individual coils, transversely shearing the trailing end of a lirst coil and the leading end of a second coil at substantially the same angle to assure the mating of the ends of the coils, welding together the strip material of the individual coils in end-to-end relation to form a continuous strip, finishing the surfaces of the continuous `strip in the weld area to form a joint having smooth sealable surfaces and a thickness substantially less than the combined thickness of the two joined strip material, storing certain of the continuous strip to assure a continuous supply of strip material during the time required for the :addition of another coil of strip material to the continuous strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension on the strip while within the vacuum chamber to facilitate tracking along a predetermined path within the vacuum chamber, heating the strip to remove gases and oxides from the strip, thermally treating the strip to maintain the strip at the desired coating temperature, depositing aluminum on opposite surfaces of the steel strip from -sources of metal vapor by condensation of aluminum vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, rewinding the coated strip material in coil form, together with the storing of portions of the coated strip material as it passes out of `the vacuum chamber during the removal of a coil and feeding the coated strip material during the winding of a coil at a faster rate than the feed rate through the vacuum chamber to substantially deplete the stored coated strip material, and then cutting olf the individual coil.

13. A method of continuous aluminum coating a steel strip comprising the steps of providing the strip material in individual coils, transversely shearing the trailing end of a first coil and the leading end of a second coil at substantially the same angle to assure the mating of the ends of the coils, welding together the strip material of the individual coils in end-to-end relation to form a continuous strip finishing the surfaces of the continuous strip in the weld area'to form a joint having smooth sealable surfaces and a thickness substantially less than the combined thickness of the two joined strip material, storing certain of the continuous strip to assure a continuous supply of strip material during the time required for the addition of another coil of strip material to the continuous strip, passing the strip through an electrolytic apparatus to clean and charge the strip with hydrogen, rinsing the strip, drying the strip, passing the strip through a seal into a vacuum chamber and maintaining a tension on the strip while within the vacuum chamber to facilitate tracking along a predetermined path within the vacuum chamber, heating the strip to remove gases and oxides from the strip, thermally treating the strip to maintain the strip at the desired coating temperature, depositing aluminum in different thickness on opposite surfaces of the steel strip from diierent sources of metal vapor by condensation of aluminum vapor on the moving strip, passing the strip out of the vacuum chamber through a seal, rewinding the coated strip material in coil form, together with the storing of portions of the coated strip -material as it passes out of the vacuum chamber during the removal of a coil and feeding the coated strip material during the winding of a coil at afaster rate than the feed rate through the vacuum chamber to substantially deplete the stored coated strip material, and then cutting olf the individual coil.

14. An apparatus for the vacuum metal coating of metal strip material comprising a coil pay-oit stand, shear means for cutting off the trailing end of a first strip portion and the leading end of a second strip portion in transverse matching relation, welding means adjacent said shear means for joining together the strip portions in aligned relation to form portions of a continuous strip, means for finishing the welded joint to provide smooth scalable surfaces and assuring a joint of a thickness substantially less than the combined thickness of the two joined strip portions, strip clamping means for holding the trailing portion of the continuous strip during the joining of a coil of strip material thereto, a looping tower for receiving and storing intermediate portions of the strip to provide a continuous strip supply during the addition of another strip portion to the strip, means for the electrolytic cleaning of the metal strip and the charging of the strip with hydrogen, rinsing means for rinsing the strip subsequent to the electrolytic cleaning, a drier for removing moisture from the strip, a compartmented vacuum chamber, entrance and exit seals at the opposite ends of said vacuum chamber, tension means at opposite ends of said vacuumhchamber and outside of said seals for maintaining v.theimoveinent of the continuous strip along a predeterminedpathwithin said vacuum chamber, strip heating `meansA ,vitllinone of said vacuum chamber compartments to remove gases and oxides from the strip, thermal control means within said vacuum chamber for controlling the temperature of the strip subsequent to the passage thereof past said strip heating means, a plurality of metal vaporizers within another of said vacuum chamber compartments on opposite sides of the path of the strip for vaporizing metal and applying metal coating to opposite surfaces of the moving strip through the condensation of the metal vapor on the strip, said metal vaporizers including active vaporizers and spare vaporizers disposed in alternating relation whereby the replacement of metal vaporizers may be made during the continuous coating of the strip, said exit seal having cooling means to preserve the components of said seal and to control the exit temperature of the strip, and means for cutting off the coated strip into readily handleable units.

15. The apparatus of claim 14 wherein the metal vaporizers effective in coating one surface of the strip have a greater output than the metal vaporizers effective in coating the other surface of the strip to provide a differentially coated strip.

16. The apparatus of claim 14 wherein the strip cutoff means includes means for coiling the coated strip into coils, a second looping tower intermediate said tension means and said strip coiling means for storing intermediate portions of the coated strip during the removal of a coil, clamp means for holding an end of the coated strip during the removal of a coil, feed means for feeding the coated strip to said strip coiling means at a rate faster than the feed rate of the strip through said vacuum chamber to substantially exhaust the stored supply of coated strip within said second looping tower during each coil winding operation, and means for cutting the coils from the strip.

17. The apparatus of claim 16 wherein the metal vaporizers effective in coating one surface of the strip have a greater output than the metal vaporizers effective in coating the other surface of the strip to provide a differentially coated strip.

18. The apparatus of claim 14 wherein the strip cut-off means is in the form of sheet cutting means for cutting the strip into a plurality of identical sheets.

19. The apparatus of claim 18 wherein the metal vaporizers effective in coating one surface of the strip have a greater output than the metal vaporizers effective in coating the other surface of the strip to provide a differentially coated strip.

20. The apparatus of claim 1S together with a sheet classifier having means for detecting sheets having pin holes therein and removing such sheets.

21. An apparatus for the vacuum metal coating of metal strip material comprising a coil pay-off stand, shear means for cutting otf the trailing end of a rst strip portion and the leading end of a second strip portion in transverse matching relation, welding means adjacent said shear means for joining together the strip portions in aligned relation to form portions of a continuous strip, means for finishing the welded joint to provide smooth scalable surfaces and assuring a joint of a thickness substantially less than the combined thickness of the two joined strip portions, strip clamping means for holding the trailing portion of the continuous strip during the joining of a coil of strip material thereto, a looping tower for receiving and storing intermediate portions of the strip to provide a continuous strip supply during the addition of another strip portion to the strip, means for the electrolytic cleaning of the metal strip, a compartmented Vacuum chamber, entrance and exit seals at the opposite ends of said vacuum chamber, tension means at opposite ends of said vacuum chamber and outside of said seals for maintaining the movement of the continuous strip along a predetermined path within said vacuum chamber, strip heating means within one of said vacuum chamber compartments to remove gases and oxides from the strip, thermal control means within said vacuum chamber for controlling the temperature of the strip subsequent to the passage thereof past said strip heating means, a plurality of metal vaporizers within another of said vacuum chamber compartments on opposite sides of the path of the strip for vaporizing metal and applying metal coating to opposite surfaces of the moving strip through the condensation of the metal vapor on the strip, said metal vaporizers including active vaporizers and spare vaporizers disposed in alternating relation whereby the replacement of metal vaporizers may be made during the continuous coating of the strip, said exit seal having cooling means to preserve the components of said seal and to control the exit temperature of `the strip, means for coiling the coated strip into coils, a second looping tower intermediate said tension means and strip coiling means for storing intermediate portions of the coated strip during the removal of a coil, clamp means for holding an end of the coated strip during the removal of a coil, feed means for feeding the coated strip to said strip coiling means at a rate faster than the feed rate of the strip through said vacuum chamber to substantially exhaust the stored supply of coated strip Within said second looping tower during each coil winding operation, and means for cutting the coils from the strip.

22. An apparatus for the continuous vacuum metal coating of metal strip material comprising means for supplying strip material in coils and joining together the individual coils with joints having scalable surfaces of and generally of the orginal thickness of the strip material, a looping tower for receiving and storing intermediate portions of the strip to provide a continuous strip supply during the addition of another strip portion to the strip, means for the electrolytic cleaning of the metal strip and the charging of the strip with hydrogen, rinsing means for rinsing the strip subsequent to the electrolytic cleaning, a drier for removing moisture from the strip, a compartmented vacuum chamber, entrance and exit seals at the opposite ends of said vacuum chamber, tension means at opposite ends of said vacuum chamber and outside of said seals for maintaining the movement of the continuous strip along a predetermined path within said vacuum chamber, strip heating means within one of said vacuum chamber compartments to remove gases and oxides from the strip, thermal control means within said vacuum chamber for controlling the temperature of the strip subsequent to the passage thereof past said strip heating means, a plurality of metal vaporizers within another of said vacuum chamber compartments on opposite sides of the path of the strip for vaporizing metai and applying metal coating to opposite surfaces of the moving strip through the condensation of the metal vapor on thestrip, means for coiling the coated strip into coils, a second looping tower intermediate said tension means and said strip coiling means for storing intermediate portions of the coated strip during the removal of a coil, feed means for feeding the coated strip to said strip coiling means at a rate faster than the feed rate of the strip through said vacuum chamber to substantially exhaust the stored supply of coated strip within said second looping tower during each coil winding operation, and means for cutting the coils from the strip.

23. An apparatus `for the vacuum metal coating of metal strip material comprising a coil pay-off stand, shear means for cutting olf the trailing end of a first strip portion and the leading end of a second strip portion in transverse matching relation, welding means adjacent said shear means for joining together the strip portions in aligned relation to form portions of a continuous strip, means for finishing the welded joint to provide smooth scalable surfaces and assuring a joint of thickness substantially less than the combined thickness of the two joined strip portions, strip clamping means for holding the trailing portion of the continuous strip during the joining of a coil of strip material thereto, a looping tower for receiv ing and storing intermediate portions of the strip to provide a continuous strip supply during the addition of another Istrip portion to the strip, means for the electrolytic cleaning of the metal strip, a compartmented vacuum chamber, entrance and exit seals at the opposite ends of said vacuum chamber, tension means at opposite ends of said vacuum chamber and outside of said seals for maintaining the movement of the continuous strip along a predetermined path within said vacuum chamber, strip heating means within one of said vacuum chamber compartments to remove gases and oxides from the strip, thermal control means within said vacuum chamber for controlling the temperature of the strip subsequent to the passage thereof past said strip heating means, a plurality of metal vaporizers within another of said vacuum chamber compartments on opposite sides of the path of the strip for vaporizing metal and applying metal coating to opposite surfaces of the moving strip through the condensation of the metal vapor on the strip, said etal vaporizers including active vaporizers and spare vaporizers disposed in alternating relation whereby the replacement of metal vaporizers may be made during the continuous coating of the sheet, said exit seal having cooling means to preserve the components of said seal and to control the exit temperature of the strip, and sheet cutting means for cutting the coated strip into a plurality of identical sheets.

24. An apparatus for the continuous vacuum metal coating of metal strip material comprising means for Supplying Strip material in coils and joining together the individual coils with joints having sealable surfaces of and generally of the original thickness of the strip material, a looping tower for receiving and storing intermediate portions of the strip to =provide a continuous strip supply during the addition of another strip portion to the strip, means for the electrolytic cleaning of the metal strip and the charging of the strip with hydrogen, rinsing means for rinsing the strip subsequent to the electrolytic cleaning, a drier for removing moisture from the strip, a compartmented vacuum chamber, entrance and exit seals at lthe opposite ends of said vacuum chamber, tension means at opposite ends of said vacuum chamber and outsideV of said seals for maintaining the movement of the continuous strip along a predetermined path Within said vacuum chamber, strip heating means Within one of said vacuum chamber compartments to remove gases and oxides from the strip, thermal control means Within said vacuum chamber for controlling the temperature of the strip subesquent to the passage thereof past said strip heating means, a plurality of metal vaporizers Within another of said vacuum chamber compartments on opposite sides of the path of the strip for Vaporizing metal and applying metal coating to opposite surfaces of the moving strip through the condensation of the metal vapor on the strip, and sheet cutting means for cutting the coated strip into a plurality of identical sheets.

References Cited bythe Examiner UNITED STATES PATENTS 2,214,618 8/ 37 Kenyon 29-33 2,311,139 2/43 Tainton 117-50 2,382,432 8/45 McManus et al. 117-107 2,748,734 6/56 Kennedy 113-33 2,754,222 7/56 Healy et al. 117-53 2,812,270 11/57 Alexander 117-50 2,876,132 3/59 Worden et al. 117-50 2,887,984 5/59 Drummond 118-72 X 2,959,494 11/ 60 Shepard 117-107 RICHARD D. NEVIUS, Primary Examiner.

Claims

1. A METHOD OF CONTINUOUS METAL COATING A METAL STRIP COMPRISING THE STEPS OF PROVIDING THE STRIP MATERIAL IN INDIVIDUAL COILS, TRANSVERSELY SHEARING THE TRAILING END OF A FIRST COIL AND THE LEADING END OF A SECOND COIL AT SUBSTANTIALLY THE SAME ANGLE TO ASSURE THE MATING OF THE ENDS OF THE COILS, WELDING TOGETHER THE STRIP MATERIAL OF THE INDIVIDUAL COILS IN END-TO-END RLATION TOFORM A CONTINUOUS STRIP, FINISHING THE SURFACES OF THE CONTINUOUS STRIP IN THE WELD AREA TO FORM A JOINT HAVING SMOTH SEALABLE SURFACES AND A THICKNESS SUBSTANTIALLY LESS THEN THE COMBINED THICKNESS OF THE TWO JOINED STRIP MATERIAL, STORING CERTAIN OF THE CONTINUOUS STRIP TO ASSURE A CONTINUOUS SUPPLY OF STRIP MATERIAL DURING THE TIME REQUIRED FOR THE ADDITION OF ANOTHER COIL OF STRI MATERIAL TO THE CONTINUOUS STRIP, PASSING THE STIP THROUGH AN ELECTROLYTIC APPARATUS TO CLEAN AND CHARGE THE STRIP WITH HYDROGEN, RINSING THE STRIP, DRYING THE STRIP, PASSING THE STRIP THROUGH A SEAL INTO A VACUUM CHAMBER AND MAINTAINING A TENSION ON THE STRIP WHILE WITHIN THE VACUUM CHAMBER TO FACILITATE TRACKING ALONG A PREDETERMINED PATH WITHIN THE VACUUM, CHAMBER, HEATING THE STRIP TO RMOVE GASES AND OXIDES FROM THE STRIP, THERMALLY TREATING THE STRIP TO MAINTAIN THE STRIP AT THE DESIRED COATING TEMPERATURE, DEPOSITING METAL ON OPPOSITE SURFACES OF THE STRIP FROM SOURCES OF METAL VAPOR BY CONDENSATION OF METAL VAPOR ON THE MOVING STRIP, PASSING THE STRIP OUT OF THE VACUM CHAMBER THROUGH A SEAL, REWINDING THE COATED STRIP MATERIAL IN COIL FORM, TOGETHER WITH THE STORING OF PORTIONS OF THE COATED STRIP MATERIAL AS IT PASSES OUT OF THE VACUUM CHAMBER DURING THE REMOVAL OF A COIL AND FEEDING THE COATED STRIP MATERIAL DURING THE WINDING OF A COIL AT A FASTER RATE THAN THE FEED RATE THROUGH THE VACUUM CHAMBER TO SUBSTANTIALLY DEPLETE THE STORED COATED STRIP MATERIAL, AND THEN CUTTING OFF THE INDIVIDUAL COIL.