US1736120A - Molybdenum alloy iron and steel - Google Patents

Description

E: New. 3%, lg

MQLDENUM ALLOY Ho Erawing.

The main objects and advantages of my in-" vention will be set forth in part hereinafter, and in part will be obvious herefrom, or may be learned by practice with the invention.

Among the principal advantages of the molybdenum-bearing pig iron of my invention are its relatively low temperature meltmg point, whereby it lends itself most flex- 16ib1y to the manufacture of alloy irons and steels in different ways and according to different processes, some of which will be described hereinafter. The percentages of molybdenum in my pig iron may be widely 20 varied so far as concerns the broader features of my invention, but these percentages will be kept within limits so that the iron will be fusible at usual steel and iron furnace temperatures. Another advantage of said prodnot of my invention is that it contains no molybdenum, and probably no other carbon compounds which are not dissociable at or-' dinary steel or iron furnace temperatures. Another advantage of this product of my invention is that it does-not require further reduction, but only intermixture, or melting together to efiect the desired percentage alloy of the iron and steel, which intermixture may be eife'cted at the ordinary and necessary temperatures of the various iron or steel making operations, even such operations wherein relatively low temperatures prevail.

So far as concerns my present invention, it is broadly immaterial as to the manner "in p which it is produced; however, the preferred process for producing the mol bdenum pig iron of my invention is describe and claimed in my copending application Ser. No. 230,381, filed November 1, 1927.

. As set forth in said application, a molybdenum-containing compound or other suitable molybdenum-containing substance or material is added to the successive charges of a blast furnace, during the usual operation 5 thereof, the addition of such molybdenum i f KISSQGK, GE: FOREST HILLS, NEW YORK am am application filed November 15, 1927, Serial No. 238,521.

compound or other molybdenum-containing substance being in such quantity as to produce the desired percentage of molybdenum alloy in the pig iron which is the product of the furnace. I

Various molybdenum compounds may be employed in' producing the molybdenumbearing pig iron of my process, as may be found convenient or desirable, such as molyb denum oxide, calcium molybdate, or molyb- 6o denum sulfide. If desired, there may be added to an ordinary blast furnace charge sufiicient of the molybdenum compound of vknown metallic content to secure the desired or predetermined percentage of molybdenum as in thepig iron, as for example, to introduce four pounds of molybdenum for every one hundred pounds of iron contained in the charge. In view of the continuous operation and periodic charging of the blast furnace with-predetermined quantities of the charging materials, the molybdenum-bearing compound, in predetermined amount, may be included with any one of the charging materials. The percentage of molybdenum obtained in 7 the pig iron will be found practically equivalent to the predetermined percentage introduced into the furnace charge.

1 The molybdenum-containing compound introduced into the blast furnace char e in the manner described, or any other suita le manner during the operation goes down through the furnace with the other ingredients of the charge. and is progressively subjected to the smelting or reducing operation'of the furnace. As the furnace operation proceeds and the charge materials are subjected to the gradually increasing temperatures and progress to a state of complete fusibility, the molybdenum is released from its compound and is absorloed practically completely into the liquid iron' as a permanent alloy thereof in the predetermined percentage proportion. v

I do not wish to be bound'byany definite theory of the alloying process which proceeds concurrently-With the blast-furnace operation, but it would appear that due to therelatively'low affinity of molybdenum-for oxygen and possibly due to the presence of powerful reducing agents, and the gradual and proessive temperature increase downwardly through the furnace, the molybdenum either directly or indirectly is completely reduced to the metallic state, and absorption thereof by 5 the iron is insured, even at the temperatures prevailing in the blast furnace. In any event, substantiall the entire molybdenum content of the moly denum-bearing compound introduced into the charge will be transmitted as 10 an alloy into the pig iron. I h .The product of my invention, molybdenumbearing pig iron, provides a material for makinga molybdenum alloy steel by'the so called hot-metal process. In connection with this process, molten pigiron containing 'a known percentage of molybdenum may be taken from a blast furnace and added .while a still molten, in predetermined quantities, to

' the charge of the steel-making furnace. If more convenient or desirable, however, the

solid molybdenum-bearingpig iron, in quantitles sufiicient to provide the percentage of.

molybdenum desired inthe finished. alloy the steel-making furnace.

the ordinary cupolafurnace.

name to this specification.

malleable or semi-steel e molybdenum content thereof being approx mately four per cent.

3. An alloy'to be used for alloy denum with steel or iron com risln denum-bearin pig iron, t e mo content thereo being approximatel cent, and said pig iron being fusib e nary iron furnace temperatures.

In testimony whereof, I have signed my ing molyba molybfour per ALAN mssocn.

steel, may be added to the original charge of i It is impracticable to produce a molybdenum alloy from cupola iron with fem-molybdenum by reason. oi its relatively high temperatu're melting. point. the possible presence of undissociable carbides. together with lack of means for proper; mixing, with consequent poor-distribution of the. molybdenum throughout the iron. The use of a molybdenum'compound v is'not available for completion of the reducmg reaction before the metalis too cool for v as an addition to the cupola so ladle is unsatisfactory for the reason that at the prevailing temperatures suflicient time casting. and eflicient and complete mixing. is

5 impracticable.

The molybdenum pig iron of my invention likewise provides a most excellent and suitable material ior addition to the charged! the cunola furnace. to produce a deei molybdenum alloy tlor. casting. Itmay be introduced as apart of the original charge of the ;-cu pola furnace in such relativepro- .iportiou as effect the desired enum in p l bution 'of the 'alloythroughout the product and without the introduction of any harmfulimpurities, whereby made from such 'alloy iron are of very superior quality and w purity. Should it be desired, the molybdenum pig iron may be melted in a separate furnace, and the molten molybdenum-hearing pc on e o o a melting ordinary tageal- .V out fromthe furnace; It insures uniform dish-is therefrombeaddedindesired ro-- whichie at ordi-,