US1116899A - Method of making sound steel castings. - Google Patents

Description

form of term-titanium,

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LEWIS 'B. LINIDEMUTH, 0F STEE specification of Letters Patent, Application filed April ii, ism. term! in 831,202.

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,li'iETHQD U5. MAKING i'SG'Um STEEL GASTINGS.

Patented Nov. 16, 1914,

To all'wfiom it may concern:

Be it known that 1, Lewis B. Lrsonnu'rn, a citizen of the United'states of America, residing at Steclton, in the county of Date phin and State of Pennsylvania, have invented certain new and useful Improvements in Methods of Making Sound Steel Castings; and 1 do hereby declare the following' to be a full, clear, and exact description of the invention, such as will enable others skilled in theart to which it ap pertains to make and use the same.

This invention relates to a method of making sound ingots or castings of steel, and has for its objectto eliminate the pipe at the center of large bodies of metal, due to their natural cooling The method consists in placing on top of the ingot or casting, after it has been poured, a coinbustible in the form of a metalloid that has a high heat of combustion and which also, when oxidized, will not enter into the steel and change its composition. That is to say, I use a substance that develops a high heat, upon oxidation when placed upon the surface of the hot metal under the action of an oxidizing blast, and which is a metalloid in the'sense that it is capable of .actingboth as an acid and a case. These substancesare, silicon, which is preferably in the form of term-silicon, aluminum, or titanium preferably in the which when free to oxidize are prone to slag formation rather than combination with or solution in the iron, so that they willnot enter the metal at at least, under most unfavorable con ditions of use, will enter only about an inch into the surface portion o'f the metal that by the oxidizing blast.

becomes agitated The substances less than that of molten iron. The heat of combustion supplies the heat required to maintain the top of the casting molten until after the body of the casting has set sufiie ciently to overcome any tendency to form a 1 e.

'lhb material used according to this process with uniform success on a large number of ingots and other heavy castings, is silicon, preferably in the form of form-silicon containing fifty per cent. silicon, to which was supplied a blast of air under pressure, supplied through a half-inch pipe over the surface of the casting, the pressure of the air being sufiicient to slightly agitate the surface of the metal added from time to time, preferably in small one per cent. In

- got; and. numerous severence show remarkable uniformity of metallic I use have aspecific gravity still rising in The form-silicon is lumps from one to three inches in diameter. The heat developed is sufficient to keen the top of the casting in a fluid condition and at a high temperature.

in order to ascertain -whether any of the silicon enters the metal, a large number of tests have been made, and samples of molten metaltaken from an ingotat about the middie of the process show no appreciable change in composition of the steel, the analyses showing in some cases silicon of about three one-hundredths of making these tests a short crop end is cut oil, not over 15% of the in analyses at the point of the metal and normal silicon content.-

It has heretofore been proposed to use carbon with a blast of air on top of an ingot, to prevent piping, but the carbon enters the steel and changes its composition, so that a great'deal more metal will have to be cut from the top of the ingot. It has also been proposed to employ a blast of top ofthe metal, which is to the silicon in thometal to produce the necessary heat; such an operation would rob the steel of its normal silicon content, so that an increase of air only on thecombine with this process also requires an abnormal to be cut oil at the top of amount or" metal the ingot to obtain an ingot of uniform conipositionthroughout.

This invention is carried out as follows when used in connection with seven and a half ton ingots, twenty-six inches square an' about seventy-eight inches long. The steel is teamed, either through the top or through the bottom of the ingot mold, and when the mold is nearly full and the metal is the mold, the air 'blast is turned on, on top of the metal with justsuflicient force to agitate the surface. Immediately after the pouring oi the metal has stopped a sniall quantity of form-silicon is thrown on top of the steel, and as the silicon is oxidized, more ferro-silicon is add ed from time to time, according to the appearance of the metal under the air jet, to keep up the temperature of the metal, and keep the top molten; As the slag increases the blast of air must be increased, in

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order to keep about three or four square 11?- inches, more or less, of the metal exposed to view. Roughly speaking, it takes about to pipe.

five pounds of ferrosilieon per ton of ingot, and operation continues an hour, more or less, until the body of the ingot has cooled sullieiently to obviate any tendency The steel when teeniecl, is in state known dead. l l olainil I, The method of making sound castings, which comprises acting on the surface of] the molten metal of the casting, until the 1 body of the casting hes solidified, with an oxidizing blast and a solid combustible that willnot substantially enter the metal, said blast oxidising the sombnstible as it melts.

[The method of making sound steel castings, which comprises acting on the surface of the molten metal, after teeming, and until the body of the casting has cooled snllieiently to prevent piping, with an sir blast and a metelloid that IS oxidized by thea 'blast as it melts, will supply heat to the casting and will not substantially enter the molten metal.

The metl'iod of making sound costings, 1 whieh comprises supplying an sir blast and l silioon to the molten surface of the casting after teeming and While cooling down sufliciently to prevent piping. I

4-. The method of making sound castings, which comprises supplying an air blast and ferro-silioon from time to time to the surface of the casting, during the cooling down I 01'. the oesting flioient to prevent piping.

The method of making sound castings, I l

. which comprises acting on the top of the molten. metal with an oxidizing blast of sufmisses fieient strength to lceep a, portion of the surtsee exposed and free from slag, and a substance that has a high heat of oxidation, is prone to slag formation and will not enter or substantially enter the metal of the casting and until the body of the casting has set or hardened, thereby keeping the surface portion of the casting molten, and preventing pipizw.

6. The method, of making sound castings, which comprises acting on the surface of the molten metal of the casting with an air blast of snflicient strength to keep a portion of the surface exposed and free from slag, and adding ferro-silieon from time to time to keep the upper portion of the casting molten until the body of the casting has set or hardened, thereby preventing piping without causing the silicon to enter or substantially enter the metal 7. The method of making sound steel caste ings, which comprises acting upon the surface of the molten steel while in the mold, until the body of the casting has solidified, with an oxidizing blast and a combustible that will not substantially enter the steel, thereby producing a solid steel casting of substantially uniform composition.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribing Witnesses.

LEWIS B. LINDEMUTH. Witnesses CHAS, R. HoLToN, Wm. B. MILLER.