USRE15407E - Pany op america - Google Patents

Description

- erties.

' measure UNITED STATES PATENT- oFI-lce.

FRANCIS FRARY, OF OAKMONT, PENNSYLVANIA, ASSIGNOR TO ALUMINUM OOM- OF' PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENN- pm or AMERICA, SYLVANIA.

plication for reissue .flle'd May T all whom it may concern:

Be it known that I, FRANCIS O. FRARY, a citizen of the United States, residing at Oakmont, in the county of Allegheny and State of Pennsylvania,- have invented a new and useful Aluminum Alloy, of which the following is a specification. 1

i This invention relates to aluminum alloys.

@I have found that alkaline-earth metals, when added in suitable proportions to alu-' minum alloys, and particularly tothose com risin aluminum, copper. andmagnesium and including or not manganese or a metal having similaraction in alloys, impart to such alloys valuable qualities or prop- By way of illustration, I ,will "now 'describe my invention in its application to specificalloys, but it is to be understood that my invention is not limited in its application to the alloys herein specifically described, my invention in its true scope being set forth by the appended claims.

imam constituent, about 4 per cent of copper and about 0.5 per cent of magnesium, and the other comprising these same constituents in substantially the proportions given with the addition of about 1 per cent of manganese. Both of these alloys are susceptible of a heat treatment, whereby their tensile strength may be increased a proximately to that of mild steel, and the1r;elon gation b from 'per centto per cent, on two-inch specimens. These alloys are therefore-very valuable for certainuses, as will be readily understood by those skilled in the art. Both of these alloys are however very diflicult and expensive to manufacture in sheet form, for the' reason that they are decidedlyhot short that is to say, a great-deal of trouble is experienced and much scrap is produced during the. hot rolling of the ingot in the process of reducing the. metal to a-state from whichfa sheet may later-be rolled, on "account of. the tendency of the metal to crack very badly.

These cracks extend from the edge of the slab into the body thereof and make necessary extensive shearing of the'edges, and in many cases the complete rejection of a considerable portion of the slabs is necessary.

"hibitive.

ALUMINUM ALLOY.

Specification of Beissued Letters Patent. Reissued July 11, 1922.

n Drawing Original m. 1,412,280, dated April 11, 1922, Serial No. 369,695, filed March 29, 1920. A

27, 1922. Serial No. 564,272. I

The application of these alloys to uses requiring that they be in sheet form is thus rendered extremely expensive-if not pro-, These objections apply particu larly to their use in the manufacture of various parts of dirigible balloons, aeroplanes and other air craft, as practically all the alloy to be used in the construction of these machines must firstbe rolled in the form of sheet,

By the addition to these alloys of a suitable proportion of'an alkaline earth metal, calcium for example, in accordance with my invention, these alloys are greatly improved, and so far as am aware novel alloys are obtained wherein a tendency seriously to crack during rolling, and particularlydur- .ingthe initial stages of hot rolling, is g'reatlv and if other conditions are properly controlled, the necessityof scrapping ingots and slabs on account of excessive cracking is done away with; The novel alloys thus obtained possess all the desirable properties of the twoztypes of alloys above described and at the'same time are easier and therefore cheaper to work.

The addition of too large an amount of calcium is to be avoided,i as otherwise the tensile strength obtained on heat treating is not as high as itshould be. As a general rule, the amount of calcium added neednot exceed 2 per cent, andless than one per cent may be used- For example in an aluminum alloy of which .the main constituent is aluminum, and containing of copper not more than 6 per cent and of magnesium not more than 2 per cent, I preferably use not more than 2 per cent of calcium. In an.

alloy of which'the main constituent is aluminum, and comprising of copper not more than 6 per cent, of magnesium not more than '2 per cent, and of manganese not more than 2 per cent, I also referably use not more than 2' .per 'cent 0 practicable alloy I recommend an alloy containing about 4.per cent'of copper, 0.6 to 1 per cent ofmanganese, from 0.3 to 1 per cent of magnesium, between 0.3 per cent and 0.6 per cent of calcium, and the balance aluminum.

The proportions of the constituents of the alloysgiven may be varied according to vacalcium. For a very r'ious requirements, without departing from the spirit of the invention, which is not to be. considered as limited to the given in any case. I

Various Well-known methods for the prepproportion aration of alloys may be used for the prep-- aration of-composit ions embodying my invention. For example, for the preparation of the aluminum, copper, magnesium, manganese, calcium alloy herein described by way 'ofillustration, preferably make use of the following rich alloys 2 A rich copper alloy containing about per cent of copper and about 80-per cent of aluminum, a

rich manganese alloy containing about 8' per cent of manganese: and about 92 per cent aluminumand a rich calcium alloy containing about 10 percent calcium, about 10 per cent copper and about v80 percent aluminum.

The aluminum used will preferably be commercially pure ingot aluminumpreferablyof a grade which contains less than 1 per cent total impurities and I use metallic ma esium of the usual commercial grade. t is not strictly essential that the rich alloys above-mentioned have the composition given, but the compositions given are approximately those of the commercial al- ,loys which are easily dbtained and for this reason I prefer to usefthemi Infpreparing the alloy the proper amounts of each of the above materials necessary to produce the de sired composition are 'weighed out. The ingot aluminum together with the rich copper and rich manganese alloys are charged into a crucible of suitable size and melted, care being taken that the [temperature shall.not

I rise above 1500 F. Thecrucible is then removed from the fire, the rich calcium alloy and metallic magnesium added and dissolved, the whole thoroughly .stirred together andthen returned to the fire to be reheated to the proper pouring temperture. When this is attained, the alloy is'skimmed and poured into rolling ingots in the usual The elements or metals composing thealloys embodying. my invention are effective constituentsof said alloys.

' operation. r I r 'The term alkaline-earth metal as used While I have particularly emphasized the increased ease of hot rolling produced by the addition of an alkaline-earth metal, herein calcium, in accordance with'my invention, there is evidence also of better rolling qualities of the alloy during the period of cold rolling which always follows the hot rolling herein is intended to include the alkalineearth metals usually referred to by that term, with the exception of magnesium.

In carrying out my invention I preferably use what is known as commercialllyi pure aluminum, whiclT always contains sma amounts of lien and silicon, and possibly other minor impurities. The word aluminum, however, wherever used in the speci fication and claims, is not to be understood as referring to. any particular kind of aluminum, but on the contrary, it is to be interpreted in its broadest sense as including any loys.

Claims. 1. -An alloy comprising aluminum, copaluminum suitable for making aluminum alper, magnesium and calcium, calcium not being the main constituent. V

2. .An. alloy comprising aluminum, copper, magnesium, 'manganese and calcium, calcium not being the main constituent.

3. An alloy comprising aluminum, copper, magnesium and an alkaline-earth metal, the alkaline-earth metal not being the main constituent.

4. An'alloy; comprising aluminum, cop-- per, magnesium, manganese and an alkalineearth metal, the alkaline-earth metal not being the main constituent:

5. An alloy having as its main constituent aluminum and comprising lesser quantities of copper, manganese,- magnesium and calciuma 6. alloy having as its main constituent aluminum and comprising lesser quantities of copper, magnesium and calcium 7 An alloy having as its main constituent aluminum and comprising lesser quantities v of copper, manganese, magnesium and an alkaline-earth metal.

'8. An alloy having as its main constltuent aluminum and comprising lesser quantities having as its main constituent aluminum, the

copper content not exceeding 6 per cent and the content of each of the metals manganese,

magnesium andv calcium not exceeding 2 per cent.

12. An alloy comprising aluminum, cop-- per, magnesium and calcium, having as Its ,maincon'stituent aluminum, the copper content not exceeding 6 per cent and the ,content alkali-earth V of each of the metals magnesium and calcium not exceeding 2 per cent.

13. An alloy consisting of aluminum, co per, manganese, magnesiumand calciumjt 6 copper content not exceeding 6 percent and thecontent of each of the metals manganese,

magnesium andcalcium not exceeding 2 per cent.

14. An alloy consisti per, magnesium and calcium, the copper conof aluminum, coptent not exceeding 6 per cent and the content of each of the metals magnesium and calcium not exceeding 2 per cent.

15. An alloy comprising aluminum as its main constituent and copper, magnesium and calcium, the copper content being about 4 per cent and the content of each of the metals magnesium and calcium not exceedmg 1 per cent.

16. An alloy comprising aluminum as its main constituent and copper, manganese, magnesium and calclum, the copper content being about 4 per cent and the content of each of the metals manganese, magnesium and calcium not exceeding '1 per cent.

17. An alloyhaving aluminum as its main constituent, and containing ofi copper about '4 per cent, of manganese from 0.6 per cent to 1 per cent, of magnesium from 0.3 per cent to 1 per, cent and of calcium from 0.3 per cent to 0.6 per cent.

18. An alloy comprisin an alkaline-earth metal an in which alumialuminum, and

num is the main constituent, the alkalineearth metal content not- .exceeding about 2 per cent. 1 v

19. An alloy comprising aluminum and calcium in which aluminum is the main constituent and the calcium content does not exceed about 2 per cent.

20. An aluminum alloy having aluminum as its main constituent and containing from about 4 per cent to about 6 per cent of copper and from about 1 per cent to about 2 per sent of each of the metals, magnesium, manganese and calcium.

21. An aluminum alloy having as its main constituent aluminum and containing from about 4 per cent to about 6 per' cent of copper and from about 1 per cent to about 2 per cent of each of the metals magnesium and calcium.

In testimony whereof, I have signed my name to this specificatio FRANCIS c. FRARY.