US2254202A - Aluminum alloy - Google Patents

Description

Patented Sept. 2, 1941 UNITED STATES PATENT OFFICE ALUMINUM ALLOY George Edward Barnes, Cleveland, Ohio No Drawing. Application July 29, 1940,

Serial No. 348,20!

2 Claims.

' to obtain strength.

Another object is to produce an aluminum alloy that may be subjected to casting, forging, rolling and machining operations without sacrificing hardness and strength and capable of resisting corrosion to a greater degree than any other known aluminum alloy.

A further object is to produce an aluminum alloy that when cast may be machined without the use of any solution, 1. e., in its dry state, thus being workable like bronze, any such operation producing a mirror-like finish free from pits, abrasions and other objectionable effects heretofore peculiar to machine operations as applied to aluminum alloy parts.

According to this invention, I make a casting alloy by compounding elements such as may be secured in the purchase of several commercial aluminum alloys of recognized standard quality, then combining these alloys with commercial aluminum (99% pure) so that the relative quantities under practical foundry practice fall by weight within the ranges set out below:

Per cent 30 Copper 4.5 to 6.0 Nickel .5 to 2.0 Magnesium .1 to .25 Titanium .1 to .25 Chromium .25 to .5 J5 Balance-Commercial aluminum (99% pure) and traces of other elements.

Total 100.0 40

Mycasting alloy is made in a manner different than commonly used and is briefly described, as follows: First, I mix the aluminum alloys with the aluminum (99% pure) in the proportions by weight indicated above (or as set forth in the practical examples hereinbelow). Second, I melt this mixture. Third, I then allow the molten mass to soak from fifteen to thirty minutes Fourth, I then pour this molten mass into molds and form ingots of my alloy. Fifth, I allow these ingots to rest or age for at least twenty-four (24) hours before remelting for such purpose as may be required.

My invention may be more readily perceived r by the practical foundryman by considering'one typical batch that I have made up for experimental purposes, as follows:

Pounds 50/50 copper-aluminum 6 20/80 nickel-aluminum 2 6/94 magnesium-aluminum 1 6/94 titanium-aluminum 1% 20/80 chromium-aluminum 1 Commercial aluminum (99% pure) 50 This mixture works out approximately and by calculation, as follows:

Per cent Aluminum 93.552 Copper 5,200 Nickel .640 Magnesium .144 Titanium .144 Chromium .320

Total "100.000

vare termed surface and inside shrink, and

is free from porosity and makes a tight, closegrained casting. Also, my alloy when cast produces parts that may be machined in their dry state to a mirror-like finish, free from dragging, pits or abrasions, and thus produces results far superior to those obtained through the use of any other casting alloys discovered to-date.

My alloy, as illustrated by the above practical example, shows a tensile strength above 27,000

pounds per square inch when made up in a sand cast test-bar andafter ageing for three days. A similar test-bar, after ageing of two to three weeks, showed a tensile strength of about 30,000 pounds per square inch with an elongation of slightly more than 2.0%.

. I find the composition of the several standard commercial alloys does vary from time to time but my tests show uniform results if the elements so commercially obtained and mixed do not vary if present within the ranges set out hereinbefore.

I therefore produce an homogeneous and stable aluminum casting alloy which may be subjected to forging. rolling and machining, with advantages and properties for superior to any heretofore discovered.

What I claim is: r

1. A casting alloy composed of the elements 5 in the relative quantities by weight within the ranges set out below: 7

' Per cent Copper 4.5 to 6.0 Nickel .5 to 2.0 Magnesium .1 to .25 Titanium .1 to .25 Chromium .25 to .5 Aluminum ..The remainder Traces of impurities and other elements.

2. A casting alloy composed of the elements in the relative quantities by weight as specifically set out below:

(without consideration of traces of other elements and impurities).

GEORGE EDWARD BARNES.