US1713766A - Alloy - Google Patents

Description

Patented May Zll, W2

GEORGE G. MARSHALL AND HAROLD S. BOOTH, OF CLEVELAND, OHIO.

ALLOY.

No Drawing.

The present invention relates to an alloy containing chromiun'r and beryllium and iron, which possesses many properties which make it of great utility in the arts.

Chromium alloys as a rule are quite heavy, that is to say, they are of high specific gravity, and by the alloying of beryllium with chromium the specific gravity of the resultant alloy is materially decreased so that structures fabricated from the alloy possess all the desirable qualities inherent in the chromium, but are much lighter than where .the alloy is made of the usual chromium alloys. v

It is obvious where the lightness of the resistant alloy is of special advantage, that the beryllium content may be increased to the maximum with corresponding reduction of iron and chromium content.

In all of the instances which have just been mentioned, the presence of the beryllium produces an alloy of lower specific gravity than would be the case if the beryllium were not present, and in addition the beryllium and chromium performs certain other useful functions in the alloy, which makes its presence desirable, as for instance, the beryllium and chromium forms a skin oxide or compound chromate upon the out side of the alloy which is very adherent and protects the underlying metal against deterioration, due to a further oxidation, which is important, particularly where the article which is fabricated out of the alloy is subj ect to repeated heating and cooling, and the temperature to which it is heated is comparatively high, which would tend to induce oxidizing effects.

The chromium, beryllium, iron-alloy exhibits the property of nonwarping even when repeatedl heated and cooled. This is an important eature, and makes the alloy particularly useful in all those places where a structure is required to withstand repeated beatings and coolings, and is also sub ect to high temperature.

A very important property of this alloy is its resistance to corrosion, due to acids as well as alkalies. As is Well known, the hot dilute forms of the various acids are exceedingly corroding in their actions upon most metals. The alloy containing beryllium and chromium and iron, is exceedingly resistant to acids and alkalies. This fact, coupled with Application filed February 27, 1923. Serial No. 621,663.

the fact that the alloy containing beryllium produces a lighter alloy than the irorr or chromium alloy alone, marks an important property, inasmuch as the usual forms of acid containers or conductors wherein iron and chromium are used as the basis of the alloy, are exceedingly heavy, and where, as in the present instant, the resultant alloy contaming beryllium is much lighter, the importance of this property will be appreciated.

In making the alloy, the ferro-chrome where ferro-chrome is used as the basis of the alloy, is heated in the electric furnace to fusion and beryllium is added, the beryllium usually being added shortly before the batch of alloy is poured from the furnace, at which time it is desirable to add a small quantity of silicon in order to produce greater fluidity and secure an easy pouring of the batch. The amount of silicon used is very small, and should not appear in the final alloy in greater quantities than 1 per cent, as the silicon tends to make the alloy grainy, and decreases its tensile strength.

The desired properties of the alloy are best exhibited in an alloy containing chromium 4% to 6% beryllium 2% to 10% and iron approximately As a specific example of an alloy produced and having the desired qualities, we would give the followmg:

Chromium 6%, iron 90%, beryllium 4%.

While the above proportions are considered to produce the best results, for certain purposes higher percentages of chromium and beryllium may be used. For example, an increase in the chromium content up to 20% raises the melting point and resistance to oxidation. The upper limits of the chromium and beryllium content have been found to be chromium substantially 42%, iron 46% and beryllium 12%. This alloy, however, is extremely brittle and hard to work but has great resistance to oxidation and is useful for its nonwarping qualities and may be advantageously used in carbonizing boxes and other articles which are required to withstand high temperatures.

An alloy having proportions of chromium, iron and beryllium within the limits above specified has a very high melting point, in the neighborhod of 2500 F and from this springs its ability to withstand high temperatures.

This application is in part a continuation of our co-pending application Serial No. 278,822, filed February 24, 1919.

Having described our invention, we claim:

5 1. An alloy containing beryllium, iron and chro ium in substantially the following proportions ;-beryllium 2% to 12%, iron 46% to 90%,chromium 4% to 42%.

2. An alloy containing beryllium, iron and 10 chromium in substantially the following proportions beryllium 2% to 10%, iron 90%, chromium 4% to 6%.

3. An alloy containing beryllium, iron and chromium in substantially the following proportions beryllium 4%, iron 90%, chr0- mium 4%.

In testimony whereof, we our signatures.

HAROLD S. BOOTH. GEORGE G. MARSHALL.

hereunto aflix