US1613571A

US1613571A - Process of making molybdenum steel

Info

Publication number: US1613571A
Application number: US70188A
Authority: US
Inventors: Frederick M Becket
Original assignee: ELECTRO METALLURG CO
Current assignee: ELECTRO METALLURG CO; ELECTRO METALLURGICAL Co
Priority date: 1925-11-19
Filing date: 1925-11-19
Publication date: 1927-01-04
Anticipated expiration: 1944-01-04

Description

Patented" 4, 1927.

UNITED STATESV'VPATENT oFFlcE.

UREDEBIJK' BECKET, OF NEW YORK, N.-Y., AS SIGNOI B T ELEGTRO METALLURGICAL COMPANY, A CORPORATION OF WEST VIRGINIA.

PROCESS OF MAKING- MOI LYBDENUM STEEL.

No Drawing.

direct processes, i. e. by processes which do not involve the preparation of metallic molybdenum or of a molybdenum alloy. In the practice fof these direct processes it has hitherto been customary to introduce molyb- 80 denum into the steel furnace or crucible as an oxide of moiybdenum or as a molybdate. When derived from molybdenite ore or concentrate, preparation of the oxide or of the molybdate -has hitherto involved a roasting 2 operation whereby the molybdenum contentof the-ore was converted into molybdenum oxide or,- under certain conditions when the roasting charge contained lime or iron oxide, into ca cium molybdate and iron molybdate, respectively. Even when any of the aforesaid chemical compounds of molybdenum have been prepared fr'om the ore in the wet way by leaching and precipitation methods, oxidation or preliminary roasting of the molybdenite or a charge mixture containing ithas been characteristic of the process-as a whole.

According to the present invention molybdenum sulfid is brought as such into reactive 4o relation to the steel bath. My investigations have shown that under suitable conditions of practice the molybdenum content of the. sulfid is recovered completely or in amount sufliciently high to represent an entirely practicable recovery ratio; and what is of vital importance from the commercial aspect, this recovery is effected with little or no attendant increase in the sulphur content of the finished metal. In other words, in the practice of the.present invention the unit cost of the molybdenum contained in the Application filed November 19, 1925. Serial No. 70,188.

finished steel may in good practice be made to approach very closely, and practically to equal, that of the molybdenum content of the original ore or concentrate.

I The following specific examples illustrate preferred procedures, as carried out in the basic electric furnace:

I. Molybdenite concentrate analyzing 54.15% molybdenum and corresponding approximately to 90% MOS was added to a heat of steel in a basic-lined electric furnace in such amount that them'olybdenum in the concentrate added was 0.43% of the weight of the .steel in thefurnace. The addition was made in this case after the first or oxidizing slag had been removed but prior to the attainment of those strongly reducing conditions which are characterized by a slag of the,carbide type. This was followed by furnace additions of washed metal, highcarbon ferromanganese and low-carbon ferrochrome, in the order stated. Three hours after the addition of molybdenite concen trate to the bath, and thirty minutes after the addition oflow-carbon ferrochrome, the heat was poured and treated in the ladle with ferrosilicon. The finished steel had the followingcomposition:

Percent.

C 0.37 Si 0.35 Mn 0.81 P 0.011 S 0.012 Cr 1.12 Mo 0.44

addition of high-carbon ferro-manganese. ,The amount of molybdenum thus added as molybdenite was equivalent to 0.40% of the metal charge. The steel, which was treated in the ladle with ferrosilicon, had the following compos1tion:

Percent. G 0.40 Si 0.27 Mn 0.68 P 0.012 S 0.017 Cr 1.12 Mo 0.35

erating agents may be added, such as bori c oxid, glass, fiuorspar, silica and basiccompounds, including compounds of the alkali metals, without departure from the present invention, provided that the process of incorporating said fluxes and agglomerants preserves the chemical identity of the molybdenum sulfid, or provided that said process brings about only in part the chemicalconversion of the sulfid into other product or products. 7 It'will be understood by those skilledfiii the art that the temperature and composition of the steel and of the slag, as well as the time allowed for their reaction with molybdenum sulfid, may exert a marked effect .uponthe percentagerecovery of molybdenum in the finished steel, and also upon. the sulphur content of the latter. More especially in the caseof open-hearth practice it is preferable under certain conditions to add the molybdenite in successive batches rather early inthe progress of'the heat, and to distribute it over the surface of the bath, rather than to make the entire addition at one time and at one location within the furnace.

I claim:

1. Process of making molybdenum steel, comprising bringing molybdenum sulfid into reactive relation with a steel bath in the absence of abnormal reducing conditions.

2. Process of making molybdenum steel, comprising bringing molybdenite into reactive relation with a steel bath inthe absence of abnormal reducing conditions.

3. Process of making molybdenum steel, comprising bringing a molybdenite concentrate into reactive relation with a steel bath in the absence of abnormal reducing condit'ions.

4. Process of making molybdenum steel, comprising agglomerating molybdenum sul fid and bringing the 'agglomerate into reactive relation With a steel bath in the absence of abnormal reducing conditions.

, In testimony whereof, I affix my signature, FREDERICK M. BECKET.