US1915824A - Treatment of metals - Google Patents

Description

June 27, 1933. c. HARDY ET AL TREATMENT OF METALS Filed May 19, 1951 lNVENTOR-S CHARLES HARD) DOA/4L0 M 66077 BY GM,DW,W

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Patented June 27, 1933 UNITED STATES PATENT OFFICE CHARLES HARDY, OF PELHAM MANOR, AND DONALD M. SCOTT, OF BUFFALO, NEW YORK TREATMENT OF METALS Application filed. May 19,

for alloying Or for purification, it is frequently desirable to introduce agents that have a lower specific gravity than the metal to be treated. The material introduced, therefore, on account of its buoyancy, tends to rise and collect at the surface; where it reacts with the molten metal mainly at its surface. When a highly reactive refining agent collects at the surface, it tends also to react with the surrounding atmosphere. When preparing alif the added alloying constituent, or constituents, has a lower specific gravity, the alloying activity may well take place only at the surface, whereas it should of course take place substantially throughout the entire body of molten metal under treatment. Results are similar with refining metals. The added refining agent, which has a lower specific gravity, tends promptly to collect on the surface, where its scavenging activity is largely restricted.

As a result of our investigations, we have determined that metal of lower specific gravity in solid form may be suitably introduced into a bath of molten metal having a higher specific gravity. The metal or metals to be added may be effectively introduced below the surface of the bath of metal to a depth at which its presence may be effectively utllized.

The present invention accordingly contemplates a method of treating metal in molten form, whether it be for alloying or for purifying purposes, or both, according to which a charge of metal to be added in solid form is introduced into a bath of the molten metal to o be treated with suflicient force to cause the charge of added metal to penetrate well below the surface of the molten bath.

A force greater than gravity is required to sink the added metal or metals deeply into the molten bath of metal to be treated. Insuf- 1931. Serial No. 538,616.

ficient penetration is normally obtained even when throwing the added solid metals into the metal bath. The mass of added metal must be forcefully and violently propelled in order to reach deeply below the surface. For this purpose, satisfactory projecting means must be employed, such as a gun, a machine gun, a powder-fired rifle, a strong spring-release device, a catapult, a compressed air projecting apparatus, or other suitable contrivance.

In the practice of the present invention, we have particularly in mind the preparation of alloys according to which an alloying metal or metals in solid form is introdued into a bath of molten metal. For example, such alloying constituents as the following may be introduced into a molten bath of steel; silicomanganese, ferro-silicon, ferro-tungsten, ferro-chrome, ferro-nickel, or any other suitable combination. The metal or metals added may be either in alloy or non-alloy form. In the practice of the invention, we also contemplate the purification or refining of metals in molten form. Such highly reactive metals'as calcium, magnesium, sodium, lithium, barium, strontium, and potassium, may be employed in suitable form.

The metal or metals to be added may be used in any suitable form. They are used in masses and may be in the form of alloys, slugs, bullets, lumps, agglomerates, briquettes or any other suitable solid form which adapts them for introduction into molten metal in accordance with the present invention.

In the present preferred practice of the invention, the added metal, or metals, is introduced in predetermined amounts. For example, in the preparation of a silico-manganese steel, the amount of silicon and manganese required may be calculated, and therefore introduced into a molten bath of steel in predetermined amounts. Tests of the metal under treatment may periodically be made to determine to what extent the alloying or purification step has proceeded. Further masses of the metal or metals to be added may then be introduced into the body of molten metal undergoing treatment in ,accordance with these determinations.

The metal to be treated may be kept in any desired vessel While undergoing the treatment operation. In the preferred practice of the invention, we introduce the metal or metals to be added to the molten metal to be treated while it is still in a ladle coming from the reduction or smelting furnace. In this manner advantage may be taken of the molten state of the metal as it comes from the furnace. The metal to be treated may of course be melted in a special treatment furnace, but this step is preferably avoided to economize in heat.

Various modifications of the practice of the invention will undoubtedly occur to those skilled in this particular branch of metallurgy, that do not depart from the spirit of our invention. The principles herein disclosed are highly useful in effecting the alloying and purification of various metals. It is particularly true of iron and its alloys, such as steel, ferro-tungsten, steel, chrome-steel, nickelsteel, chrome-nickel steel, silico-manganese steel, fcrro-silicon steel, copper and its alloys, silicon manganese, nickel and its alloys, aluminum and its alloys, magnesium and its alloys, calcium and its alloys, sodium and its alloys, and in fact practically all metals and their alloys. From our foregoing disclosure, it will be seen that we have developed a method according to which counteracting diiferences in specific gravities may be effectively overcome by velocity.

The invention may be considered in con junction with the figure of an apparatus adapted for a practice of the process of the invention, as illustrated by the accompanying drawing. The apparatus shown comprises a melting pot 1 constructed of suitable material, containing a body or bath of molten metal 2. The pot is closed on all sides, except for a suitable opening 3 in the top thereof; the opening being preferably small so that oxidizing air may not have ready access to the body of molten metal and to prevent loss of metal by splashing.

A mechanical shooting device 4 is shown above the pot, with its discharge end extending downwardly into the neck of the pot. The shooting device consists of an elongated cylinder 5 open at its lower end and closed at its upper end by means of a cap 6. A plunger head 7 mounted on a slide rod 8 of appropriate length fits in the interior of the cylinder. A compression spring 9 fits around the rod, one end of the spring being attached to the plunger head 7 and the other end of the spring being attach-ed to the cap 6.

A pair of tension springs 10 and 11 are suitably mounted exterior of the cylinder 5. The lower ends of the springs are attached to lugs 12 and 13, respectively, permanently aifixed to the cylinder 5 near its lower end. The upper ends of the tension springs are 5 attached to laterally extending shoulders emme 14 and 15, respectively; the shoulders in turn being permanently attached to the rod 8 at or near its upper end. A suitable handle 16 is mounted on the rod 8 at its upper end.

In order to introduce a charge of solid metal 17 deeply into the body of molten metal confined in the pot 1, the charge is placed within the cylinder 5. The handle 16 is pulled upwardly to compress the spring 9 and to extend the tension springs 10 and 11, whereby the plunger head 7 is moved toward the cap 6. In order to gras the shooting device manually, a handle ot shown) is suitably attached to the cylinder 5; so that it may be gripped with one hand while the handle 16 is gripped with the other hand. The charge of solid metal 17 is permitted to slide in engagement with the plunger head 7 in its retracted position. On releasing the handle 16, the charge of solid metal is shot or projected at high velocity into the body of molten metal 2, and may well reach a position near the bottom of the pot indicated by the numeral 17. The cylinder 5 is kept out of contact with the molten metal 2.

We claim:

1. In the method of treating metal in molten form, the step which comprises shooting a charge of metal of lower specific gravity in solid form at high velocity into a bath of the molten metal to be treated with suificient propellant force to cause the charge of added metal to penetrate deeply below the surface of the metal bath, said charge of metal of lower specific gravity in solid form being shot into the bath of molten metal by a shoot ing device held above and out of contact with said bath.

2. In the method of treating metal in molten form, the step which comprises shooting a compact charge of metal having a lower specific gravity in solid form at high velocity into a bath of the molten metal to be treated with sutlicient propellant force to cause the charge of added metal to penetrate deeply below the surface of the metal bath, said charge of metal of lower specific gravity in solid form being shot into the bath of molten metal by a shooting device held above and out of contact with said bath.

3. In the method of treating metal in molten form, the step which comprises shooting an alloy charge of lower specific gravity in solid form at high velocity into a bath of the molten metal to be treated with sufficient propellant force to cause the charge of said alloy metal to penetrate deeply below the surface of the metal bath, said charge of metal of lower specific gravity in solid form being shot into the bath of molten metal by a shooting device held above and out of contact with said bath.

4. In the method of treating metal in molten form to produce an alloy, the step which comprises projecting a mass of alloying metal Ian in solid state under sufiicient velocity to carry the mass of alloying metal deeply into the bath of molten metal to be alloyed, said mass of alloying metal in 7 solid state being shot into the bath of molten metal by a shooting gevlilce held above and out of contact with said 5. In the method of refining metal in molten form, the step which comprises projecting an agglomerate containing a highly reactive refining metal admixed with metal of the kind to be refined under suflicient velocity adapted to carry the agglomerate deeply into the bath of molten metal to be refined, said agglomerate being shot into the bath of molten metal to be refined by a shooting device held above and out of contact with said bath.

6. In the method of preparing an alloy of steel, the step which comprises mechanically shooting a charge containing a predetermined amount of alloying metal in solid form at high velocity deeply into a molten bath of the steel, said charge being shot into the molten bath of steel by a shooting device held above and out of contact with said bath.

7. In the method of preparing an alloy of steel, the step which comprises mechanically shooting a charge containing a predetermined amount of alloying metal in solidform at high velocity deeply into a molten bath of the steel, said charge of alloying metal comprising at least one of the following ferro-silicon, ferro-tungsten, ferrochrome, ferro-nickel, silico-manganese and the like, the charge of alloying metal in solid form being shot into the bath of molten steel by a shooting device held above and out of contact with said bath.

8. In the method of treating metal in molten form, the step which comprises shoot ing a charge of metal of lower specific gravit in solid form at high velocity into a bath oi the molten metal to be treated with suffieient propellant force to cause the charge of added metal to penetrate deeply below the surface of the metal bath, the charge of metal of lower specific gravit in solid form comprising at least one of t e following calcium, magnesium, sodium, lithium barium strontium, potassium and the like, sai charge of metal of lower 8 ific gravity in solid form being shot into t e bath of molten metal by a shooting device held above and out of contact with said bath.

9. In the method of treating a bath of molten metal, the step which comprises mechanically shooting a charge of metal in solid form at high velocity deeply into the bath of molten metal, said charge of metal um, strontium, potassium and the like; the

charge of solid metal being shot into the bath of molten metal by a shooting device above and out of contact with said bath of molten metal.

10. In the method of treating a bath of molten metal, the step which comprises mechanically shooting a charge of metal in solid form at high velocity deeply into the bath of molten metal, the charge of solid metal being shot into the bath of molten metal by a shooting device above and out of contact with said bath of molten metal.

11. In the method of treating a bath of molten steel, the step which comprises mechanically shootin a charge of metal in solid form at high ve ocity deeply into the bath of molten steel, said charge of metal in solid form comprising at least one of the following: ferro-silicon, ferro-tungsten, ferrochrome, ferro-nickel, silico-mangane'se, calcium, magnesium, sodium, lithium, barium, strontium, potassium and the like; the charge of solid metal being shot into the bath of molten steel by a shooting device above and out of contact with said bath of molten steel.

12. In the method of treating a bath of molten steel, the step which comprises mechanically shooting a charge of metal in solid form at high velocity deeply into the bath of molten steel, the charge of solid metal being shot into the bath of molten steel by a shootmg device above and out of contact with said bath of molten steel.

13. In the method of preparing an alloy of steel, the step which comprises mechanically shooting a charge containing a predetermined amount of alloying metal in solid form at high velocity deeply into the bath of molten steel, the char e of solid alloying metal being shot into t e bath of molten steel by a shooting device above and out of contact with said bath of molten steel.

In testimony whereof we aifix our signatures.

CHARLES HARDY. DONALD M. SCOTT.

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