US1156995A - Method of coating metal. - Google Patents

Description

J A. HANLON.

METHOD OF COATING METAL. I APPLICATION FILED sin. 18. m2.

1,156,995. i Patented Oct. 19, 1915.

INVEN'I'OR.

WI'I'NESSIL'S: '6 4 5 T BY an 'd m X EMM am W I ATTORNEY.

JOHN A. HANLON, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO HANLON-GREGORY GALVANIZING COMPANY, OF PITTSBURGH, PENNSYLVANIA, -A CORPORATION OF PENNSYLVANIA.

METHOD OF COATING METAL.

Specification of Letters Patent.

Application" filed September 18, 1912. Serial No. 721,080.

To all whom it may concern: Be it lmown that I, JOHN A. I-IANLoN, a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Coating Metal, of which the following is a specification.

This invention relates to a method of coating metal, and particularly to a method of coating steel or iron with lead, zinc, or compositions thereof.

The object of the invention is to provid a method whereby strips of iron or. steel may be provided with a very thin coating of metal applied in such manner that the coating metal is spread very evenly and forced into the pores of the base material, to

form a firm and secure bond or physical con- .nection therebetween, to enable the coated material to be bent or folded upon itself or at very-sharp angles, without breaking, cracking, stripping or peeling of the coating metal.

'In the drawings, which illustrate one embodiment of apparatus for carrying out the method, Figure 1 is a longitudinal sectional elevation through the coating tank with a scraping device therein; Fig. 2 is a plan view of the scraping device; Fig. 3 is a transverse section on the line 33, Fig. 2, one of the levers being shown in dotted lines in raised position; Fig. 4 is a longitudinal section on the line 4-4, Fig. 2; and Fig. 5 is an enlarged longitudinal section on the line 55, Fig. 2. I

Although in the past attempts have been made to provide strips of steel or iron with a thin closely adhering coating of zinc or lead, or compositions thereof, which will not crack, break or peel, this has never been accomplished successfully to" my knowledge. In the case of lead it has commonly been found that it will not adhere to the surface of the steel or iron or, if it does adhere, then only in blotches or spots and not continuously', while, in the case of zinc, it has always been necessary to run the strip orshect through the bath of metal at such a slow rate of speed as will permit the base metal to be brought up to the temperature'of the bath before leaving the same, which rate of speed is so slow as to permit a comparatively thick coating of zinc to be deposited on the strip, the wiping or stripping rolls or other devices commonly employed, and through which the strip passes as it emergesfrom the pet, being unable to so materiallyreduce or thin and .spread this thick coating that it strip is bent at sharp angles.

By my invention I propose to immerse or submerge a strip in a bath of the coating metal, by passingit therethrough, and then, after it emerges from the. bath of metal,

applying scrapers to both sides of the strip, said scrapers being of such type and so aphigher rate of speed than according to prior practice, thereby reducing the period during whlch it is submerged. in the metal, and the amount of coating metal which will adhere thereto. The strip may also, if de= sired, be passed successively through a plurality 'of similar scrapers which, in turn, will remove increments or additional portions of the coating metal. According to this method the scrapers not only remove from the base material a large proportion of the coating metal which has adhered thereto, but also by pressure applied thereto, compact the coating, spread it, and force it into the pores of the base metal, thereby forming a very thin coating having a firm physical bond or connection to the base ma- Patented Oct. 19, 1915. i

will not peel or crack when the sheet or terial so that the finished product may be bent or folded either upon itself, or at very sharp angles, without breaking, cracking, stripping or peeling. This product, I believe, has never before been successfully produced. a

To carry out the method I employ an apparatus of suitable construction, one embodiment'thereof beingshown in the drawings. This comprises a suitable pot or kettle l which is of cast or plate iron or steel,

which is mounted 'on a suitable foundation 2 and is filled or nearly filled with molten metal 3 which it is desired to coat upon their forward-ends, are provided with downwardly bent hooks 6 to hook over the transverse bar or supportt, which is preferably so disposed as to lie a short distance below the level of the molten metal 3 in the pot. At the rearward end of the frame 5 its side 7 members form a pair of handles 7 which may be used to lift the scraping device from the pot and place it in position therein when desired. Between the slde members 5 are transverse members '8, 8 to tie the frame the sets of scraping devices are alike,

together and make it rigid.

As shown in Fig. 2, bers 8, ofwhich two or more may be used, as desired, are located near the forward end of the frame 5 and in'such position asto be above the surface of the molten metal within the pot. These transverse members eachcarry a pair of oppositely disposed sets of scrapers or wiping devices, thus making four setsof such devices in all, although more .may be used, if desired. Since all of it will be necessary to describe only one thereof.

The scraping devices are preferably .of the co nstruction illustrated and claimed in my companion application Serial No. 721,-

' 079,- filed September 18, 1912, and briefly scraping device described comprise a plate or support 12 secured to the transverse member 8, and

having remov'ably bolted thereto a lower .scraping or wiping device 13, comprismg a flat knife, blade or strip of rolled steel having either a square or rectangular upper edge portion, but preferably the latter, .over which the strips of metal being coated pass through the apparatus. Above each of the scrapers 13 is mounted a cooperating upper 14: which is removably bolted to a supporting. member 15 and which is of the same'construction as the lower scraping device. The support 15 is pivotally secured at 11 to the upper end of a pivot member 11 vertically adjustable in a supporting ledge 10 on the frame, and, at its outer end, is provided with an upwardly offset handle member 16 to enableit and the upper scraping deviceto be raised from or lowered upon the strips passing through the device. It will also be understood that the handle member 16 moves between guides 18 on the frame and may be as long or as short as desired and may also be provided with suitable means, such as an aperture 17, for the attachment of a weight 17 thereto.

The pot 1 is first filled with metal 3, such as iron, and supplied in the form of a coil, is passed between the upper and lower scraping knives of'the first pair and then, in a similar manner, between the upper and lower scrapers of the second and succeeding pairs. The coil is supported on a suitable spindle and the free end of the strip is led v tactwith the upper surface of the strip, the transverse memwhereby the sharp edges of the scrapers of the first set remove or scrape off a considerable po'rtion of the surplus bath metal and dross from both sides of the strip passing through the apparatus, which drains into the melting pot 1. At the same time, the scrapers 13 and 14 of the first set spread compact and thin the coating metal and force it into the pores of the strip. The

upper scrapers causes them, and the lower scrapers as well, to compact the coating metal and positively force the same into the pores of the base material. After the strip has passed the first set of scrapers it passes through a second similar set which removes a second portion of the coating metal and thin and spread the same and force it more firmly into physical connection with the base metal. Additional sets of scraping devices may be used if desired, although in practice, I have found that two sets are sufficient.

In coating metal, as heretofore carried out, it has never been the'practice to operate the winding or coiling apparatus, to cause the strip to travel at a speed faster than the rate of flow of the molten metal itself, the common speed being about 15 feet per minute. From experience it is found that molten lead or zinc will flow upon the surface of base metal, at a given rate, which rate is never exceeded by the rate of travel of the strip or sheet through the bath. By my improved method the surplus coating metal may be forcibly removed at almost any rate of travel of-the strip through the scrapers.

Consequently the stripbeing coated can be passed through the apparatus at a very high rate of speed, say, for example, at. a rate of'lOO feet per minute, more or less. The scraping devices are placed comparatively close to, but at the same time are spaced away from, the surface of the molten metal bath'and the strip reaches the scrapers before the metal has achance to solidify or set to any appreciable extent. In the case of zinc 1t is found that steel or iron may be pressure applied to the levers carrying the produced with a three per cent. coating on 23 gage, in other Words, with a coating of three pounds of zinc to every hundred pounds of base material. This coating is very considerably thinner than any that has heretofore been applied and steel or iron thus coated with a zinc or lead coating may be bent or folded, as described, Without any danger of the surface coating cracking, breaking or peeling. When the pot or kettle is filled with molten lead, it is found that the lead adheres to the surface of the base material, probably due to the high rate of speed at which this passes through-the apparatus, and is thinned and compacted and bound to the base material to form a thin coating therefor. At the same time the coating is continuous and uninterrupted and will not crack, break or peel.

What I claim is 1. The method of coating metal strips, consisting in passing the same through a bath of molten metal at a rate of speed faster than the natural rate of flow of the molten metal on said strips at or near the bath, to wit, at a speed in excess of fifty feet per minute, and applying edgedscrapers with material pressure to both sides of the strips metal and dross before it solidifies and spreading and pressing the remaining thin coating into the pores of the base material to theerby form a firm bond or physical connection between the strip and coating metal.

2. The method of coating steel or iron strips with softer metal, consisting in passing the same through a"molten bath of the softer metal at a rate of speed faster than the natural rate of flow of the molten metal on said strips at or near the bath, to wit, at a rate of speed in excess of fifty feet per minute, and after it has left the bath and before the molten metal has left the strip forcibly scraping both sides of the strip to thereby remove the surplus coating metal and dross before it solidifies and spread and thin the remaining coating and force it into the pores of the strip to thereby form a firm physical bond or connection therewith and a thin permanent coating for the same.

In testimony whereof, I have hereunto set my hand.

JOHN A. HANLON. Witnesses:

ELBERT L. HYDE, J. L. TREFALLER, Jr.

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