US1441479A - Process for making an alloying alloy - Google Patents

Description

Jan. 9, 1923. 1,441,479

W. BENNETT. PROCESS FOR M KING AN ALLOYING ALLOY- FILED S PT- 8. I922.

lnveniar Wilsm Ee/z/zett 7 Patented Jan. 9, 1923.

UNITED S ATES PATENT OFFICE.

I WILSON BENNETT, 0F WELLINGTON, NEW ZEALAND.

PROCESS ro'a MAKING An ALLOYING Ame.

I Application filed September 8, 1922. Serial No. 586,998.

To all whom it, may concern);

- Be it known that I, WILSON BENNETT, a

citizen of New Zealand, residin at Wellington, New Zealand, have invente certain new and useful Improvements in Processes for Making an Alloying Alloy, of which the following is a specification.

This invention relates to the process of making an alloying alloy referred to in my application for patent 57 2,100 filed June 30, 1922.

In that a plication I pointed out the advantages 0 making my "alldying alloy of chromium, etc., directly from theores, thus obviating the step of previously refining the ores of chromium in making my" alloying alloy.

An object of the present inventionois to.

produce this alloying alloy in a continuous process and without removing the.alloying alloy from the furnace in which it is produced.

With this and other objects in view which will appear as the description proceeds, the

invention consists of the novel features hereinafter described in detail, illustrated in'the annexed .drawing and more particularlypointed out in the appended claims.

' angles toFig. 1;,and,

' 40 1 A and B are carbon electrodes and C is a of metal of approximately the same compo- Referring to the] drawings wherein the same letters represent corresponding parts in the different views v Figure 1. is a sectional view of a suitable furnace for use in carrying out my inven-' tion with'the electric circuits and contacts diagrammatically shown connected to the furnace;

Fig. 2 is a section of the furnace at right Fig. 3 is a sectional view of a detail of-the water cooled bottom electrode.

water cooled electrode in the bottom of the furnace, said bottom being preferably'lined with a magnesite material 0, the test of the body of the furnace being the ordinary material. The electrode C, I preferably make sition as the alloy formed in this furnace.

D, E, F, G, H and J represent switches,

the special functions of which will be later referred to in detail. They may be closed or opened to make or break certa'incircuits leading from a transformer 'K to .the electrodes A, B and C. The'electrodes A and 'B may be supported by an arm L which in.

turn is supported on a standard P attached meet the requirements of to the side of the furnace or supported on a base at the side of the furnace. This standard is screw-threaded at its upper end at Q, and a screw extended from an upper part M attached to the arm L so that when the screw is rotated by a handle R the electrodes A and B will be raised and lowered in the furnace for a purpose to be described hereafter.

N are digrammatical representations of a water tube passing upwardly and then horizontally and/downwardly through the bottom of the electrode C, and water passed through the tube N will serve the purpose of keeping cool the electrode during-the operation of the furnace.

I have discovered that certain metals and metalloids when .alloyedtogether exercise a very beneficial effect in minimizing the rusting or corrosive properties of iron, when these" metals and metalloids are present in certain predetermined quantities, for example, I have found that chromium, nickel,

copper, molybdenum, vanadium and silicon,

when added in certain percentages to iron, produce a ferrous alloy highly impervious to rust and corrosion, in addition to adding exceptional physical properties, such as the ability of withstanding the action of acids, alkalis and gases to a marked degree.

I have also found that these alloys are suitable to both hot andicold working and can be readily manufactured into shapes to ordinary commercial use.

In order that the iron alloys shall most advantageously possess the qualities herein described, it is necessarythat'the constituent metals be substantially free from carbon,

sulphur, manganese and phosphorus, which seriously interfere with the working properties of the iron alloy, a carbon contentof one pgr cent being the maximum amount. It

.is even preferable to obtain an iron alloy with a carbon content of less than one per cent. I Indeed, the total of carbon, sulphur,

' may be added in the form of cupric-nickel metal such as Monel metal.

In carrying out my entire process I take as a base, decarbonized and refined. iron such as is used for ingot iron or steel manufacture, which may be produced in the ordinary manner. in an open hearth furnace, care being taken to eliminate carbon, manganese, sulphur and phosphorus to the lowest possible extent. To the molten iron I add an alloying alloy of chromium, nickel, copper,

molybdenum, vanadium and silicon in such percentages to produce the quantity and quality of the completed iron alloy desired, using aluminium as a. deoxidizing, degasifying andsolidifying agent.

My method of preparing the alloying alloys is of prime importance and I prefer to use the furnace illustrated in the drawing in making this alloyingalloy.

To produce the alloying alloy -I first intimaitely mix crushed chromite ore wit-h coke and pile this charge of material around the electrodes A .and B.. This charge is then covered with a. slaggingmaterial of lime and fluorspar. The furnace is then set into operation as an arc furnace by closing the switches E and either G, H or J, depending upon the amount of current that. I wish passed through theelectrodes AB. the switches D and F being left open. This will produce an are from the lower extremities of the electrodes A and B. The charge is completely melted and the result is a fused mass of chromlum, iron, carbon and metalloids. This product is known commercially as ferro chromium. In thls stage of the process the molten bath of metal will be in the metal minimizes the chromium oxide losses in theslag to a marked degree which otherwise are relatively high when silicon is switches carbon content required is obtained.

not employed during the decarburizing process.

The electrodes A and B are now depressed so as to barely clear the metal surface, allowing only a small gap between the molten metal and the electrodes to prevent the metal bath from being impregnated by carbon I from the electrodes. The furnace is now operated as a. resistance or incandescent furnace with the upper electrodes A and B connected in parallel to one pole and the water cooled metal electrode C situated in the base of the hearth, connected to the opposite pole. This ma be accomplished by closing F and either G H or J, depending on the amount of current. desired, and opening switch E. The temperature is raised and the decarburizing process proceeded with until a test piece shows the required carbon content of the finished alloying allo The additional alloys of nickel, copper, molybdenum and vanadium should be introduced at this stage. They may be added in the form of metals or ferro alloys of these metals, previously prepared. The chromium and iron contents of the metal bath should be determineduand. chromite ore or ferro chromium should be introduced if the chro- "mium content should be found to be toolow,

excess of the desired amount. The decarburizing process is proceeded with until tile.

11 practice: it will be found'that the components of the alloying materials are easily oxidized, especially'the silicon and chromium- These oxidized products form a-chromiferous'silicate slag. This slag can be employed to great advantage as fluxing material for subsequent meltings/and decarburization.

The slag is carefully removed, leaving the metal bath with a clean surface. A covering of crushed lime is then thrown on the metal bath and the temperature of the furnace is raised .to a. point whichwill-reduce the lime very quickly to a fluid state. When the lime slack is melted, coke dust is carefully thrown on top of the slag around and between the electrodes A, B, care being taken not to allow coke to come in contact with the molten metal. The upper electrodes A, B, are elevated and the furnace operated as an arc furnace at high temperature to form a calcium carbide covering of the lime and coke. Immediately the coke dust is thoroughly incorporated with the lime, the upper electrodes are lowered to slightly above the metal bath surface as before described by turning the. handle R and operating the screw to lower the electrodes, and the furnace is then operated as a resistance or incandescent furnace, setting up a flow of metal under the calcium carbide flux. This is the third stage of the process and will be found in practice to speedily eliminate sulphur, phosphorus, manganese and silicon to an extremely lowdegree. The completed alloying alloy is then run into the ladle and the refined iron previously referred to as ob tained from the open hearth furnace is poured directly into the mixture. 4 It is very desirable in order toobtain satisfactory results that the completed iron alloy be made with accuracy, and to insure" that the resulting compound shall contain the proper proportions as specified. T0 attain this result a ladle with a suitable Weighing attachment is advisable and the desired percentage, by weight, of the alloying alloy run into the ladle from the electric furnace Into this molten mixture sufficient of the refined iron from the open heart-h furnace is poured to produce the quantity and quality of the completed iron alloy desired. Aluminium or'silicon either, or both, being inserted into the ladle toact as a deoxidizing,

I degasifying and solidifying agent during I is then run into ingots or suitable moulds to,

the mixing stage. The completed iron alloy produce castings, transferred to soaking pits, rolled, pickled, annealed and manufactur ed into sheets and shapes in the usual manner.

It is evident-that my invention permits of various modification, for example, the proportion of copper, nickel, molybdenum, vanadium or silicon may be changed considerably, and under certain conditions one or more of theseelements may be omitted, al-

though I prefer to use them approximately in the-percentages specified, Y i

I claim as my invention 1. The process of producing an alloying alloy which consists in mixing clironium ores Wath ore reducing agents in an electric I furnace, passing an electric are through the mixtureto reduce and refine the metals, removing the resulting slag, adding a decalbur zmg mixture including a high content of-sihcon to the remaining metals and passmg a current through the mass to reduce the Y slag.

silicon.

carbon to a low percentage and to eliminate excessive chromide oxide losses during the decarbonization, and removing the resulting 2. A process of producing an alloying alloy from ores, which consists in mixing chromite ores with a carbonaceous material, covering the same with a basic material, then passing an are through the ores to melt and reduce the same, removing the same with a slagging material and passing an electric aretherethrough, removing the slag thus formed, coveringthe top of the metal with lime, a chromium ore, mill scale and silicon, passing a current through the mixture to rid the alloy of its carbon content as described; 7

6. The process set forth in claim 5, together with the step of adding some form of'nickel and copper to the resulting alloy.

7. The process-set forth in claim 5 togethe r with the, step of adding nickel, copper, molybdenum and vanadium to the alloy formed. 3 r, p

In testimonv whereof I afiix my signature in presence of two witnesses.

Witnesses:

CHAS. B; COMPTON, 'Srnwan'r L'. WHITMAN.

. loy as set forth in claim 1 and adding to the WILsoN BENNETT.

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