US1531784A - Sheet metal - Google Patents

Description

C. W.' HAZELETT March 31. 192s.

SHEET METAL l Filed Dec. 13, 1921 2 Sheets-Sheet 1 w M4 y mw M M l W c. w. HAzELET-rf March 31. 1925.

SHEET METAL Filed Dec. 13. '1921 2 Sheets-Sheet 2 JOO ,DIH/fritas Mama c55-z' Zweig/2702 MMM, jffajgA/Q/S Patented Mar. 3l, 1925.

UNITED STATES APATENT OFFICE.

'BY MESN E ASSIGNMENTS, CLEVELAND, OHIO'.

SHEET METAL.

Application led December 13, 1921.

To all whomr t may concern.'

Be it known that I, CLARENCE W. HAZE- LETT, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga 5 and State of Ohio, have invented a certain new and useful Improvement in Sheet Metal, of which the following is a full, clear, and exact description, reference being had to the VVaccompanying drawings.

This invention relates to cast sheets of metals of the lower and medium melting temperatures, as distinguished from metals having high melting temperatures, such as steel. I have discovered that certain characteristics of thin cast sheet metal are coincident with results of greater economy of F manufacture, greater strength, more uniform physical characteristics, and very much higher degree of resistance to corrosive actions.

Up to the time of the present invention steel metal in commercial use is manufac-v tured almost entirely by rolling processes,

although a small amount may be made by casting sheets of small area in molds. I have produced a metal resulting in the above 4 and other advantages, and capable of being manufactured in large commercial quantities at an exceeding low cost, by a continuous casting process, resulting in a continuous strip of predetermined thickness and Width, delivered at a highrate of speed. Such a process, adapted for making the sheet metal herein described, is fully disclosed and claimed in my copending application led November 11th, 1920, Serial -Number 423,- 309. Y

It is my intention to`conne the present application entirely to my sheet metal. To

4.0 determine the characteristics of my sheet metal, as to its strength, acid resisting propertics and other properties, comparison may be made with the characteristics of sheetsr formed by methods previously known and used.

To fully disclose this invention, I illustrate the characteristics of the crystalline structure, and describe its properties as embodied in sheets made of a certain lead alloy,

and compare these properties and characteristics with those of rolled and cast sheets of the same alloy, made in the forms heretofore used. Therefore, in the drawings, Fig. l, is a section perspective of a piece of my sheet 5 metal considerably enlarged; Figs. 2, 3, 4

serial No. 522,108.

and 5 are reproductions of micro-photographs, taken after etching, illustrating the crystalline structure, progressively from one side of the sheet to the other and taken at right angles to the plane of the sheet, approximately in the position shown by the small circles with which each of these figures is connected; Fig. 6 is a reproduction of a micro-photograph taken after etching and in the same plane as the sheet at the side on which Fig. 5 terminates; Fig. 7 is a reproduction of a micro-photograph of a sheet of similar thickness cast in a mold; Fig. 8 is a reproduction of a micro-photograph illustrating the struc-ture of a rolled sheet; ig. l9 is a similar reproduction of cast pig or in ot of the same alloy as the sheet illustrated in Figs. l to 6. The micro-photographs from which Figs. 7, 8 and 9 are taken are made at 100 diameters, as are the other views 2 to 6. p

My sheet metal is hereinafter more fully described in reference to the drawings and its particular novel characteristics are summarized in the claims.

The sheet embodying my invention and discovery has within the meaning of the appended claims and as above outlined, certain very marked novel features of crystalline structure. As at present successfully practiced, the results may be illustrated by an alloy in wide commercial use, for example, for storage battery plates, linings for acid tanks an other uses, and composed of 7 per cent antimony and 93 per cent lead. Variations of these proportions and other ingredients in similar alloys produce structural results quite like those illustrated in In Fig. l, l0 designates a sheet being a representation of a small piece taken from a commercial sheet of my metal made in a continuous strip and enlarged to five dameters for clearness of illustration.

Discussing first, the crystalline structure of sheets of this antimony lead, examination under microscope has disclosed that at one side of the sheet, it has a coarse crystalline structure while at the other side the crystals are comparatively small. This outstanding feature is noticeable in my sheets made of various metals, and particularly when made by my process, described in the previously mentioned application. At one side of the sheet of metal, the crystalline structure is similar tothe normal crystalline structure of a cast piece of material with comparatively large crystals, while at the other side of the sheet are fine small crystals, and the size from one side to the other grows progressively smaller with considerable uniformity. In'this discussion, I am referring to sheets from a few thousandths of an inch in thickness up to sheets of one eighth of an inch or somewhat greater, although it is to be understood I do not wish to limit my invention to particular thickness to consider its scope as. relating to comparatively thin sheets of material.

Illustrating this decreasing of the size of the crystals from one side of the sheet to the other, we may refer to Figs. 2, 3, 4 and 5, the circle of vision of which is illustrated to define its position with relation to the sheet by the circles 2a 3, 4aL and 5a, respectively. Fig. 2 is taken to include/the upper edge of the sheet, that is from the upper surface into the metal, say one fourth of its thickness. It shows the coarser crystals. It can be noted that the crystalline structure reproduced in Fig. 3, is somewhat finer than that of Fig. 2. Fig. 4 which is taken still farther fro-m the upper side of the sheet 10 is still smaller than that of Fig. 3 and the size of the crystals is very noticeably smaller than those of Fig. Zat the top of the metal sheet. In this view the crystals grow noticeably smaller from the upper part of Fig. 4 to the lower part, while Fig. 5 which includes the lower edge of the sheet shows the very fine crystalline structure at the lower side o the sheet. The upper part of this Figure 5 (which includes the same Zone as the lower part of the igure 4) shows a crystal formation substantially the same as Fig. 4 at its lower side.

The relationship of the crystals, one to another, appears substantially uniform, whether examined t right angles to the plane of the sheet, or whether the section is taken parallel to the plane of the sheet. To illustrate this, Fig. 6 is taken on an etched portion'of the lower side of the sheet, and it will be noted that the crystalline structure is very si 'lar to that of the lower part of Fig. 5, alt ough the plane of the section is at right angles to that of Fig. 5.

Summarizing the characteristics of my sheet, then, we find that regardless of thickness, it has a crystalline structure at any one point somewhat similar to that of the ingot of the same material, but varying in size from very fine crystals at one side to comparatively coarse, much larger, crystals at the other side of the sheet. The variation is substantially uniformly progressive from one side of the sheet tothe other.

By way of illustrating the marked differences of my sheet material, from sheets of the same material made by methods heretoof the sheet, other than fore known and having the usual crystalline structure of such material, as heretofore used in commercial quantities; I have taken this same alloy made in a sheet of the same thickness by the usual process of rolling. The crystal formation of this sheet is illustrated in Fig. 8. It will be noted that the crystalline structure is substantially broken down or obliterated. This rolled sheet is an example of the widely used commercial rolled sheet of lead and its alloys. Fig. 7 is a view showing the structure of mold cast sheets of this same alloy as illustrated in Figs. 1 to 6. The same alloy cast in an ingot or pig, without the influence of any mechanical pressure and allowed to cool naturally, that is simply by radiation is illustrated in Fig. 9. It will be noted that this produces a largeV pronounced crystalline structure having marked differences from my sheet at any particular point.

`As noted in the legends on the-drawings, Figs. 7 8 and 9 are each reproductions of photographs taken at 100 diameters, the same as are Figs. 2 to 6 inclusive.

In working toward the end of producing commercial sheet metal more economically than by methods heretofore used, I have sought to produce at the same time a metal having superior properties for the different uses to which it may be put. This I have accomplished by the metal now described, for example, a series ofl authenticated tests have developed that my sheet of antimony lead used for the purposes of this f illustration has very much larger tensile.

strength than sheets or strips of rolled lead, of the same alloy. For example, the strength tests show that my metal is approximately 85% greater'in tensile strength and ultimate strength longitudinally of the sheet. I furthermore find that the rolled sheet is very much weaker transversely of the direction of its rolling than it is longitudinally of its direction of rolling, whereas my sheet has the same strength in all direct-ions of the plane of the sheet. That is to say that transversely of the sheet, thetensile strength of m sheet metal is the same as longitudinally of it and it has therefore much higher tensile strength in all directions of the sheet than rolled sheet lead has in the direction of its greatest strength. I also find that a rolled sheet has a tendency to break or split when sharply folded over on itself longitudinally of its direction of rolling, even though it ma p fail to break or split when sharply folde on itself transversely of the direction of rolling; whereas my sheet, being of uniform characteristics in all directions of the plane of the sheet, has no such pronounced tendency to break or split when folded sharply upon itself along any direction of the plane of the sheet.

For use in lining of acid tanks, containtwo mold members ing, for example sulphuric acid or nitrous vitriol, I find my sheets have much greater life than the same alloy when rolled. Tests of applications of sulphuric acid (I-IZSO4) specic gravity 1.15 applied for 168 hours disclose that my sheet metal showed no loss of weight, whereas rolled lead similarly treated showed 0.14 per cent loss. Using the same acid specific gravity 1,8 for the same length of time and at a temperature of 20 to 25 degrees centigrade, my sheet metal showed about one third as much loss as rolled metal of the same alloy. The same was true of a nitrous vitriol test. The use of this metal for lining of acid tanks is very advantageous, offering Ia cheaper metal of higher resisting qualities and greater length of life in service. f

It is to be understood that the illustration of ant-imony lead as embodying this invention or discovery, is not to be taken as a limitation of this invention to this material, as practice has demonstrated that many other metals are included within the scope of this invention. The characteristics, both crystalline and physical properties, of other metals having melting points of suiiciently low temperature as to be feasibly manufactured by my method, are very similar.

For convenience, I may mention in this specification that a method of manufacturing the metallembodying the characteristics of this invention has been found to result from the use of stationary and lrelatively moving members between which the molten metal is caused to flow and pass therefrom in its frozen state. The temperatures of the cure a relative dierence between them, causing one side of the sheet to cool somewhat more rapidly than the other, while on the slower cooling side (i. e., higher temper- :zi-ture ithe cooling is such as to freeze the material just as it passes from between the mold members.4v

.I claim is: il. :sheet of metal of predetermined 'thickness having uniform surfaces and having leef-ore any further treatment fa different are so governed -as to secrystalline structure at and near one side of the sheet than the structure at and near the other side of the sheet.

2. A sheet or' meta-l cast but not otherwise treated and of the same constitution throughout but having a variation in crystalline formation ranging from coarse crystals at one side ofthe sheet to fine crystals at the other side of the sheet.

3. A sheet of cast metal of the same constitution throughout having defined regular opposite surfaces and before further treatment consisting of a fine grain crystalline structure at one side and a comparatively coarse grain crystalline structure at the other. Y Y

' 4. A cast sheet of metal or metal alloy of the same constitution throughout but having a variation in crystalline formation so that one side of the sheet are coarse grains or crystals, at the other side of the sheet are line grains or crystals, while intermediate the two sides is an intermediate size of grains or crystals.

5. A cast thin sheet of metal having one side structurally different from the other and having a tensile strength greater in any line of the plane of the sheet than rolled sheet of the same composition and thickness is in the line of its greatest strength.

6. A cast sheet of metal formed in a continuous strip and having a crystalline structure throughout and having a tensile strength transversely of the strip equal to that longitudinally of the strip.

7. A cast sheet of metal formed in a continuous strip and having no apparent grain in any direction of the material as compared to the grain of a rolled sheet.

8. A cast metal sheet formed in a continuous lstrip fof indefinite length and having a crystalline structure uniform longitudinally of "th-e slsieet, though varying from large to fine y'crystals from one plane surface of the .she-'et to the other.

YIn itestimony whereof, I hereunto aix my signature.

CLARENCE lV. HAZELETT.

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