US1431621A - Method of manufacturing steel - Google Patents

Description

Patented Oct. 10, 1922.

UNITED STATES r 1,431,621 PATENT OFFICE.

JAY O. BENEKER, OF SEATTLE, WASHINGTON, AS SIGNOR OF ONE-THIRD TO FREDERICK F. M INTOSH, F GLEN OSBORNE, PENNSYLVANIA, AND ONE-THIRDTO ,WILLIAM B. SKIKLE, OF CORAOPOLIS, PENNSYLVANIA. i

METHOD OF MANUFACTURING STEEL.

No Drawing..

To all whom it may concern:

Be it known that I, JAY C. BENEKER, a citizen of the United States, a resident of Seattle, in the county of Kingand State of \Vashington, have invented a new and useful Improvement in Methods of Manufacturing Steel, of which the following is a specificatlon.

In the manufacture of manganese steel,

the usual practice is to add the manganese to a molten bath of steel in the form of a ferro-allo containing about 80% manganese and a out 6% carbon. Because the commercial grades of ferromanganese are so high in carbon,a very considerable amount of carbon is added to the bath, and it is therefore very diflicult, if not entirely impossible, to economically produce a low-carbon highmanganese steel. The steels which are men ufactured by the usual process and which contain more than quite small percentages of manganese are hard and brittle because of the combined effect of high carbon and manganese, and they have a very limited field of usefulness.

The object of the invention is to provide a method whereby low-carbon high-manganese steel may be economically iuanufac tured without substantial departure from the usual manner of procedure followed in the making of steel.

Low-carbon high-manganese steel as contemplated herein is steel containing not more than about carbon and not less than 5 about 1.00% manganese. In the practice of the invention manganese is added to a molten bath of steel in the form of a silico-nu nganese alloy, the silicon, or a large portion of it, being eliminated by oxidizing it. In

this way, the manganese, which has less at finity for oxygen than does silicon, becomes available for allo ing with the steel, and, the carbon of the si ico-manganese alloy being low, steel low incarbon and with the desired percentage of manganese is produced. The method may be carried out in various ways, but in the preferred practice the oxidation of silicon is brought about chiefly by blanketing the steel with a slag containin metallic or other oxides which may be readily reduced by the silicon.

The invention may be practiced in various ways. According to one manner of procedure, a melt of steel is worked down in a basic Application filed March 1, 1921. Serial No. 448,896.

furnace in the usual way of making Low carbon steel, and the slag is so controlled that it has a low silica content, preferably less than 15%. This may be done b causing the slag to have a large content 0 linie and a normal content of manganese and iron. Near the end of the heat the silico-man'ganese is introduced into the bath, the alloy, containmg from about 10 to 20% silicon and 50 to 70% man anese, 'the remainder being iron and a sma 1 amount of carbon and other impurities. The low-carbon content of the silico-manganese as compared to ferro-manganese alloys is due to the presence of silicon. The amount of silico-manganese thus introduced will depend of course upon the percentage of manganese desired in the steel. In the reaction that takes place, the silicon of the silico-manganese alloy, or a large ortion thereof, becomes oxidized by the oxides of the slag, the silicon having a greater atfinity for oxy en than does manganese. This reaction ta es place lar ely because of the low silica content of the slag. It will, of course, be understood that some of the silicon becomes oxidized by the oxides in the molten steel, and that some may remain in the steel. However, actual practice oi the invention has shown that'when the method is practiced in the manner described a large portion of the silicon enters the slag as silica. The amount of silicon remaining in the steel may be controlled by the composition of the slag and the period of time, after adding the silico-nianganese, which the heat is held in the furnace before tapping.

According to another and the preferred manner of procedure, a slag is maintained high in manganese oxides. This may be done by using considerable amounts of manganese ores either with the charge or as later additions in oxidizing the carbon of the melt. When the SiliCO-lllflngEtIlQSB is added, a larger percentage of manganese becomes alloyed with the steel for a given amount of silicO-manganese added than in the first described manner ol procedure. A large part of the silicon reduces the manganese oxides of the slag with the double result that the manganese is reduced from the slag and becomes alloyed with the steel and the silicon is eliminated as silica in the slag. Some of the silicon may reduce the iron oxides of the slag wth the same general result.

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The method is applicable to the manufac ture of alloy steels low in carbon and high in manganese and which also contain other allowing metals such as chromium, molybdenum, tungsten, vanadium, copper, nickel, et cetera. For example, these alloying elements may be added as oxides in the charge or slag and be caused to enter the steel by the strong reducing action of the silicon, or they may be added to the molten bath in the usual form of ferro-alloys or metals.

The second of the above described manners of procedure may be modified by removing a first oxidizing slag so as to free the molten bath from phosphorus and other impurities, and then making up a high-manganese high-line slag for the reaction with the silicon. This practice is of special advantage in electric furnaces, but may also be used in the manufacture of steel in other furnaces for obtaining better control of the process.

As a specific example of the practice of the invention, I made a melt of steel using as a charge 73,000 lbs. of scra'p, 17,000 lbs. of cast iron, 3,800 lbs. coke, 2,000 lbs. manganese ore of about 45% manganese, and 5,500 lbs. burnt lime. After the carbon content had been worked down to about 05%, an addition of 1,000 lbs. of silicoma-nganese was made, the alloy being a 22% silicon and 55% manganese. About ten minutes later, a further addition of 1,000 lbs. of the same silico-manganese was made, and about fifteen minutes later the heat was tapped. Analyses of samples of the slag taken before and after the addition of the silico-manganese sowed that the silica content of the slag was increased about 41}%. The resultiqg steel was found to contain 1.13% manganeseand .06% carbon, and a test of the steel, after being heated to redness and quenched rather slowly and mildly, showed it to have an elastic limit of about 80,000 lbs., an elongation in two inches of 25% and a reduction in area of 55.4%.

The foregoing Specific example of how the method has actually been practiced is given, not by way of limitation, but as an illustration of the process and of the character of the resulting steel.

As previously stated, manganese steel made according to the process is low in carbon. Resulting from its low-carbon highmanganese content, the steel has unexpected physical properties. It has high strength and elasticity and is remarkably ductile in proportion to its strength, and may be advantageously used for many )urposes where strong ductile steels are esired. Steels made according to the process which have less than about 0.10% carbon and more than about 1.50% manganese have special commercial value.

I claim:

1. The method of manufacturing steel containing not more than about 35% carbon and not less than about 1.00% manganese. which consists in introducing a silico-manganese alloy into a molten bath of steel in its course of manufacture, and eliminating silicon by oxidizing it.

2. The method of manufacturing steel containing not more than about 35% carbon and not less than about 1.00% manganese, which consists in blanke'tin a 'bath of steel with a slag low in silica, introducing a. silica-manganese alloy in such bath, and eliminating silicon by reducing the oxides of the slag. I

3. The method of manufacturing steel containing not more than, about .35'% carbon and not less than about 1.00% manga nese, which consists in blanketing a bath of steel with a sla high in manganese oxides, introducing a si ice-man anese alloy in such bath, and eliminating si' icon by its reducipg action on the manganese oxides of the s a n testimony whereof, I have hereunto set my hand.

JAY C/BENEKE-R. J Witnesses: H. KING,

' .C. S. HUNTOON.

C Certificate of Correct ien. It. is hereby certified that the name of the second-mentioned assignee in Letters Patent No. 1,431,621, granted October 10, 1922, upon the ap Iication of Jay C. Beneker, of Seattle, Washington, for an improvement in Methods of Maimfacturing Steel, was erroneously written and printed as William B. Skikle, whereas said name shouldhave been written and printed as William 2?; Skihkle, as shown by the record of assignments in this oflice; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiiee.

Signed and sealed this 7th day of November, A. D., 1922.

[BILL] KARL FENNING,

Acting Commissioner of PM.