US2157741A - Aluminum alloys - Google Patents

Description

Patented May '9, 1939 PATENT OFFICE ALUMINUM ALLOYS Edward A. Schmeller, Lakewood, Ohio, assignor of one-third to Frank I. Schmeller, Rocky River, Ohio, and one-third to JohnL. Schmeller,

Lakewood, Ohio No Drawing. Application February 4, 1939,

Serial No. 254,687

3 Claims.

This invention relates to an improvement in aluminum alloys. More particularly, it has in view alloys of aluminum requiring no heattreat* ment and having special machining qualities, and

also exhibiting desirable physical characteristics.

in the way of high tensile strength, suitable hardness, and a high degree of elongation. The 9.1--

loys combine with these qualities a number of other advantageous characteristics, such as resistance to oxidation and corrosion. The alloys are of extremely fine grain, and machining opertions result in a surface of a highly finished appearance.

These alloys, as stated, have high tensile strength and elongation without heat treatment.

and while other alloys, after heat treatment iii-- volving additional expense, may show comparable tensile strength and elongation, the cost of manufacture is greater and they have the disadvan- 1 tage of losing the increased physical characteristics, such as tensile strength or elongation upon being subjected to heating operations. The alloys of the formula herein set forth when used without special heat treatment may be freely welded or subjected to heating eflects without losing the characteristics stated. They at all times exhibit the qualities of high tensile strength and a-high degree of elongation, and at the same time provide the most satisfactory material for precision machining operations.

The alloys are of very wide application industrially, and while in no way limited to'use for fabrication of various structural parts for machines and the like, they are particularly suited for such use, especally in equipment requiring precision of manufacture and good appearance.

Heretofore there have been many alloys embodying various proportions of aluminum, mag

nesium, copper and the like, and certain elements, such as titanium, have been used ,to improve the grain structure of the finished product.

However, in many instances thealloys heretofore produced have involved complicated steps in alloying of the various elements, or in the develop-- ment of tensile strength of the. alloys through heat treatmentand the like, and this expense and the incidental disadvantages of heat treatment are avoided in the present invention.

The principal object of the invention is to provide alloys wherein the aluminum content is maintained at a relatively-high percentage, and wherein the other elements ofthe alloy are accurately proportioned to have combined action to increase the tensile strength of the finished product.

Another object of the invention is to provide alloys of aluminum having a high degree of tensile strength without sacrificing other desirable physical characteristics, suchas high degree ofelongation. 7

Another object of the invention is to provide aluminum alloys having high tensile strength, and a high degree of elongation and physicalcharac- .teristics without the necessity of heat treatment for such product.

Another object of the invention is to provide an aluminum alloy resistant to corrosion, and at the 4 same time having an unusual degree oftensile strength and elongation,and adapted for machine operations to a greater degree than other alloys having like physical characteristics.

Another object of the invention is. to provide an alloyof aluminum for use without heat treatment, buthaving a high degree of tensile strength and elongation comparable to those of. heattreatedalloys, which may be freely welded with-' out losing such high degree of tensile strength and elongation and other physical characteristics as would be the case with alloys receiving such qualities-through heat-treatment, wherein subsequent heating would destroy the original heattreating eifects. Y

Other and further objects of the invention will appear in the course of the followingdescription.

Some variations in the formula may be made, 3 but a relatively high percentage of aluminum, it will be noted, is used in every instance. 'Thus, one typical formula which has given most excellent results and showing without heat-treatment a tensile strength of 29,900 pounds with 11 per cent elongation in one instance, and a tensile strength of 31,500 pounds and an elongation of about 10 per cent in another instance, comprises the following:

ill

Aluminu 9 .65 Titanium .20 Copper 1.75 Tin 1.50 Zinc ,75 Magnesium g .90 Chromium- .25

Through the use of the following formula an increase in the elongation at the expense of tensile strength has been obtained:

Aluminum 94.95 Titanium .15 Copper L 1.50 Tin 1.25 Zinc 1 .75 Magnesium .40

The titanium and tin together produce an un-- usually fine grained dense product having great tensile strength, and at the same time having exceptional capacity for free machining, and presenting a finished surface after having been so machined. The combination of elements set forth produces an alloy in each instance of wide industrial application, which, in addition to having high tensile strength and a high degree of elongation, has fine appearance and capacity to res st oxidation and corrosive effects. While in the instances above stated the alloys will be found satisfactory for most uses without subsequent heat-treatment, it is not intended to restrict the use of the invention to the extent that certain specialized treatment shall not be applied in the event some very'unusual application 'of the alloys is to be made, particularly under certain high temperature conditions, or where some extraordinary-specifications have to be fulfilled. The widespread, and almost universal use of the alloys, without heat treatment, is provided for by the special formulas above set forth, which, as stated, have the advantage of low cost of production, and permanence of physical'characteristics, when welding or like operations are carried on.

Other modes of applying the principle of my invention may be employed instead of those explained, change being made as regards the means and steps herein disclosed, provided the means stated by any of the following claims or' the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. An alloy of aluminum for use without heat treatment consisting of about 1.75 per cent of copper, 1.50 per cent of tin, .20 per cent of, titanium,,..75 per cent of zinc, .90 per cent of magnesium, .25 per cent of chromium, the balance being aluminum.

2.'An alloy of aluminum for use without heat treatment consisting of about 1.75 to 1.85 per cent of copper, 1.50 to 1.75 per cent of tin, .20 per cent of titanium, .75 per cent of zinc, .90 per cent of magnesium, .25 per cent of chromium, the balance being aluminum.

3. An alloy of aluminum for use without heat treatment consisting of about 1.75 per cent of copper; 1.75 per cent of tin, .20 per cent of titanium, .75 per cent of zinc, .90 per cent of magnesium, .25 per cent of chromium, the balance being aluminum.