US1949112A - Riveted plated aluminium article - Google Patents

Description

Patented Feb. 27, 1934 UNITED STATES PATENT oFncE 1,949,112 RIVETED PLATED ALUMINIUM ARTICLE Gustav Schreiber, Bitterfeld, Germany, assignor to I. G. Farbenindustrie Aktiengesellschaft, Frankfort-on-the-Main, Germany No Drawing. Application July 8, 1931, Serial No. 549,574. In Germany July 18, 1930 4 Claims. (Cl. 29-181) It is well known that certain aluminium alloys having a high mechanical resistance, particularly alloys belonging to the duraluminum type, have a very limited resistance to the action of sea-water and similar corroding agents. In order to overcome this deficiency it has been proposed to provide articles made of such high 15 strength aluminium alloys with a skin or plating of a metal having a high resistance to corrosion, particularly technically pure aluminium. Thus, an article combining a high mechanical strength with a surface which is particularly resistant to 5 corrosion is obtained. The method in question has been widely employed for the manufacture of light metal sheets, and products obtained in this manner have become known under the names of Alclad or Alplat.

Insofar as a riveting of such articles is required, this was hitherto generally efiected by means of duraluminum rivets, so as to ensure high mechanical strength also in the combination. However. it has transpired that the vicinity of such rivets is liable to particularly violent corrosion, due to the relatively large electrolytic potential difference between the rivet material and the plating metal. On the other hand, the employment of rivets of pure aluminium, which recommends itself from the point of view of smallest possible difierence in electrolytic potential as compared with that of the plating metal, is impracticable owing to the inferior mechanical strength properties of the pure metal. Accordingly, the pres- 4C ent invention provides for a rivet material having at the same time a high strength and an electrolytic potential remaining approximately equal to that of the coating metal, namely technically pure aluminium.

1,; I have ascertained that alloys containing bemainder aluminium, have a mechanical strength which is entirely sufficient to resist the stresses to which rivets are subjected, and at the same time do not give rise to any perceptible corrosion in contact with pure aluminium. Thus, rivets made 6 from these-alloys fulfill the object of the present invention.

The mechanical strength of the alloys to be employed for making rivets according to the pres- .ent invention can be further improved by incorporating therein a small quantity of manganese (between about .3 and 1 percent).

Whenever technically pure aluminium is mentioned as the metal constituting the plating of the articles, it is to be understood that this term, in the sense of the invention, also comprises any alloy or metal having substantially the same electrolytic potential as technically pure aluminium itself.

I claim:

1. A structure comprising sheets of a high strength aluminum alloy coated with technically pure aluminum and rivets joining such sheets, the rivets being composed of a high grade aluminum alloy containing between about4 and 7% of magnesium and having an electrolytic potential remaining approximately equal to that of technically pure aluminum.

2. A structure comprising sheets of a high strength aluminum alloy coated with technically pure aluminum and rivets joining such sheets, the rivets being composed of an alloy of between aboutAand 7% of magnesium, the balance being aluminum.

3. A structure comprising sheets of a duraluminum alloy coated with technically pure aluminum and rivets joining such sheets, the rivets being composed of an alloy of between about 4 and-7% of magnesium, the balance being aluminum.

4. The structure defined in claim 2 wherein the alloyof the rivets contains between about 4 and 7% of magnesium and about .3 and 1% of manganese, the balance being aluminum.

GUSTAV SCImEIBER.