US1718685A - Ferro-aluminum alloy and method of making it - Google Patents

Description

Patented June 25, 1929'. I 1,718,685

' UNITED STATES PATENT OFFICE.

RALPH n mum, on MENANns, AND HENRY ,A. :nE ERIEs, E ALBANY, NEw YORK,

AssIeNo s T0 LUDLUM STEEL ooMrAN 0E WATERVLIET, NEW YORK, A con- PoRATI'oN OF NEW JERsEY. v

FERBO-ALUMINUM ALLOY AND METHOD OF MAKING IT.

Ho Drawing. Application filed April 25, 1927. Serial No. 186,570.

Attemptshave been made heretofore to up to the desired 60%. This procedure of make alloy steels containing substantial introducing the aluminum in two stages as amounts of aluminum; but great difliculties described makes it feasible to introduce the areencountered,particularly when it is dedesired amount of aluminum without the diffi sired to have the aluminum present in a defificulties which are otherwise experienced, as nite predetermined proportion. These difdescribed above. It is importantthatneither ficulties arise from the fact that aluminum too much nor too little of the aluminum be has a lower melting point than iron, is lighter used 111' the deoxidizing step. If the amount than iron, and has great aflinity for oxygen. 1s either too large or too small a scum or to When aluminum is added to a molten bath dross will form consisting I principally of of steel, it will melt quickly, float on the suraluminum oxide which will make impossible face, and rapidly oxidize. An uncertain part the addition of the desired amount of alumif th l i ill th r f r pass ofi as num or its forming the desired alloy. The slag and in addition th ti f th formation of the dross or aluminum oxide 15 aluminum oxide may be held in the steel in h p f he bath once started, its formaa finely divided state. This latter condition lon continues progressively as the further is very objectionable and renders the steel aluminum is added. The production of a unfit for commercial use. The impossibility fcrro-alummum of a definite chemical comof making the alloy to any definite specificaposltionwould under such conditions become 20 tion in this way is obvious. The action of the IHIPOSSIblGJ aluminum just described has resulted in its A typl al alloy produced by our method use as a deoxidizcr o preventive against \Vlt-lllll the range desired is 21S fOllOlVSf oxidation of molten steel, and its use has been Per cent. restricted to this purpose. f f .055 r 535 By our method, described below, it be- Slhcon 0.58 comes possibleto obtain alloys of aluminum Iron 45.23 and steel with the aluminum present in any Alumlnum 54.00 so desired proportion within very narrow limh proportions of 40% iron and 60% a1umi and the p' p lment'lon may be num are based on the theoretical formula to stated as the provis on of a method of pI'0- Al p d it ill b t d th t th iducmg such alloys: tion Whose analysis is given approximates Our invention is based on the fact dismi -1 1 covered by us that the difliculties pointed out method f preparing this alloy iabove are almost entirely absent if the alumi- Hates the loss f some zf t i bl 35 T111111 is added to-the Steel bath in the tion of the aluminum through oxidation.

a l of composltlon which would make it impossible to make the as f y P05511319 of 111011 and alloy of anydefinite aluminum content; and aluminum. The difficulty fl also eliminates the danger of the inclusion or of mlkmg Such a y 0f h compoltlon occlusion in the finished product of any alumimentloned; and a Partof 01117 lllventlqn 15 h num oxide which would render the steel unfit new method next described of preparmg this for uses we Want to put i to. 20450 alloy. This alloy of substantially 40% steel and TolJrepal'e thls alloy of steel and 60% aluminum content is intended principalalumlnuln We Proceed as follows: ly for use in connection with the preparation t5 W? first melt steel scrap next to be described of alloys containing! any of sultable composltion. An electric furnace ll d i d proportion f l i m is convenient for this purpose. Th molten though we do not wish to be understood as bath is then deoxidized by adding a small limiting ourselves in this respect. amount of aluminum, onlyasuflicient amount We 'have found that the addition to a 5U of this metal being added to form a very thin molten bath of steel of alloy'of the composi film of molten aluminum on the surface of the tion indicated by the formula Al Fe, that is, bath. Next suflicient molten or preheated of substantially 40% iron and 60% aluminum aluminum is added to bring the percentage content, results in a melting of this alloy and a uniform mixing of the aluminum content through the melt, Without its floating to the surface and there oxidizing. The alloy, we have noticed, takes longer to melt, and this slower melting may have something to do with the good results obtained. We have found that adding aluminum to the steel .in a combination of iron and aluminum in almost any proportion probably gives better results than adding the aluminum by itself; but the best results are obtained with the proportion of aluminum and iron described above. The results I are markedly inferior when a departure from the proper proportion of about 7% plus or minus or more of either constituent is made. With an alloy containing iron in percentages of 10 to 20 and the balance substantially aluminum, the advantage, if there is any, has become so slight as not to be noticeable.

We claim:

1. In the preparation of a ferro-a-luminum alloy the steps of melting iron, adding a small amount of aluminum thereby deoxidizing the iron, and then adding sufficient aluminum to alloy the steps of melting iron, addin" just n h sufiiclent aluminum to form a thin film on the surface, and then adding sufiicient melted aluminum to bring the aluminum content up to 60% of the initxure.

4. In the preparation of a ferro-aluminum alloy, the steps of melting some iron, adding a small amount of aluminum, thereby deoxidizing the iron, adding a suflicient amount of aluminum to bring the aluminum content up to 60% of the mixture, and adding such an amount of the alloy so formed to a batch of molten iron as will give the desired aluminum content to the resultant alloy.

RALPH P. DE VRIES. HENRY A. DE FRIES.