US1357549A - Apparatus for high-temperature uses - Google Patents

Description

UNITED STATES PATENT @FEWQE FRANK A. FAHRENWALD, OF CLEVELAND HEIGHTS, OHIO.

APPARATUS FOR HIGH-TEMPERATURE USES.

No Drawing.

.7 0 all whom it may concern:

Be it known that I, FRANK A. FAHREN WALD, a citizen of the United States, resid- This invention relates to alloys and has 7 for its especial object the provision of an inexpensive and mechanically strong composltion of matter which shall withstand repeated exposure to high temperatures without material oxidation, disintegration or change of shape. A great need exists for such an alloy in the manufacture of heat treating boxes; carbonizing boxes; lead pots; furnace parts; retorts for the distillation of wood, coal oil and oil bearing shales; containers for the production of calcium cyanamid; doors, chains, link and rabble arms for metallurgical furnaces; and many other metallurgical and chemical relations. Also such alloys in case they have the requisite hardness are of great value for cutting tools and tools for working hot metal. All the foregoing uses are grouped under the expression Apparatus for high temperature uses.

The essential desiderata of such appara tus are cheapness and availability, coupled with reasonably long life. Containers, boxes, and some other articles have been made from certain alloys of nickel and chromium, and serve very effectually the uses to which they are put but their expensiveness is absolutely prohibitive for most purposes, and the same is true of most other compositions heretofore proposed for such uses. The object of my invention is to secure a suflicieiiitly resistant alloy for most practical purposes with the use of inexpensive ingredients and without requirin expensive processes of manufacturing. 1 y improved alloy may be either cast directly to shape or by suitable precautions in composition can be machined as hereafter set forth.

-Although special substances may be added for special purposes as hereafter set forth my improved apparatus is ordinarily made from an alloy containing essentially the following ingredients, (the first column showing substantially the preferred compo- Specification of Letters Patent.

Patented Nov. 2, 1920 Application filed. August 25, 1919. Serial No. 319,756.

sition'and the second column the variat1ons):

Iron 70% (%75%) Chromium 15% (10%20%) Cobalt 13.5% (10%-,20%) Manganesel .5% .2%1% Silicon .5% .2%3% Carbon .2%-3% The iron constitutes the base of the alloy and is chosen for its cheapness, its amount decreasing with the excellence of the composition, although preferably preponderant in all cases. The chromium affords resistance to oxidation at high temperatures and increases the solubility of the minor constituents thus improving the physical properties of the alloy. The cobalt is employed for its toughening and hardening qualities. Cobalt in an amount of 10% or greater has a hardening effect superior to that produced by any amount of nickel whatever. In quantities less than about 10% cobalt is not appreciably superior to nickel in this regard, and sufiers the drawback that its price is about three times that of nickel, while above about 15% to 20% its hardening effect does not increase proportionally to the increased price consequent upon its use. The manganese is employed as a scavenger and to improve the casting qualities of the alloy. The silicon has a decided hardening effect and also the added quality of shielding other ingredients against oxidation although in its larger quantities it tends to produce brittleness which restricts its use;

The carbon tends to produce hardness, increases the resistance of the alloy to deformation at points below fusion and also i11- creases the fluidity of themolten alloy thus assisting in the casting. If the carbon and silicon are both restricted to .5% or less of the alloy, the articles cast therefrom can be readily machined after annealing.

The addition to the alloy of from about 1% to about 8% of a tungsten-like metal (by whichImean tungsten or molybdenum) greatly increases its resistance to distortion at high temperatures and so improves it for many uses as for example in tools for working hot metal.

N 0 special precautions are required in the manufacture of the alloy since it can be made either in crucibles or by the electric furnace method although I prefer to employ the method described and claimed in my application filed simultaneously herewith and denominated case E. The only precautions necessary are to restrict the carbon and silicon to the desired limits and this is pe culiarly easy with my improved process although it can be accomplished in other ways. It is also necessary to restrict the sulfur and phosphorus to less than about .05 each which can be effected by a proper selection of the ore coupled with the use of suitable slags and furnace linings as will be well understood by those skilled in the art of iron metallurgy. It will also be understood that other ingredients can be added than those herein listed and generally that many variations in composition are permitted within the scope of the claims hereto annexed.

Having thus described my invention what I claim is 1. Apparatus for high temperature uses made from an alloy containing a preponderance of iron together with from about 10 to per cent. of each of the metals cobalt and chromium, and at least about 2% of each of the substances carbon, silicon, and manganese.

2. Apparatus for high temperature uses made from an alloy containing from about 10 to about 20 per cent. of each of the metals cobalt and chromium, together with from about 2% to 3% of each of the substances carbon and silicon, the bala c being mostly iron.

Apparatus for high temperature uses made from an alloy containing a preponderance of iron alloyed with ten to twenty per cent. of cobalt and small amounts of carbon, silicon, and manganese, the balance consist ing essentially of one or more metals from the chromium group.

4;. Apparatus for high temperature uses made from an alloy containing a preponderance of iron together with about ten to twenty per cent. of each of the metals cobalt and chromium, and about one to eight per cent. of a tungstendilre metal, and also small amounts of carbon and silicon.

Apparatus for high temperature uses made from an alloy containing substantially iron 70%, chromium 15%, cobalt 13% to 14% and fractional percentages of carbon, silicon, and manganese.

In testimony whereof, I hereunto aiiix my signature.

FRANK A. FAHRENWVALD.