US1373908A - Manufacture of steel - Google Patents

Description

UNITED STATES PATENT OFFICE.

ALADAR PACZ, OF CLEVELAND, OHIO, ASSIGNOR TO GENERAL ELECTRIC. COMPANY, A CORPORATION OF NEW YORK.

MANUFACTURE or STEEL.

No Drawing.

To all whom it may concern:

Be it known that I, ALADAR PACZ, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a new and useful Improvement in the Manufacture of Steel, of which the following is a specification.

My invention relates to improvements in the manufacture of steel and while of gen eral application to steel manufacture it applies more particularly to the manufacture of so-called alloy steels, in which there is incorporated with the steel one or more metals, such as tungsten, vanadium, chromium, molybdenum and uranium to produce steels suitable for tools, vehicle parts and other articles requiring metal having especial hardness, toughness, tensile strength, etc. The object of my invention is to pro duce steels having better physical characteristics and also to render such steels more uniform and free from defects.

According to my invention, I incorporate with the steel a certain percentage of tantalum or niobium or both and either of these or both may be incorporated in the steel alone or in combination with such metals as tungsten, vanadium, chromium. molybdenum o-r uranium or combinations of these, depending upon the nature of the steel desired. The incorporation of the tantalum or niobium improves the steel in any case and my invention, in its broadest aspect, comprehends the utilization of tantalum or niobium in the manufacture of steel in general. It is to be understood, however, that my invention relates more particularly to the so-called alloy steels where the production of a superior metal is the main object sought and where the cost in the steel, provided the desired qualities are secured, is not of such controlling importance as in the case of ordinary steel.

The toughening and hardening properties given to the steel by niobium or tantalum are increased as compared with those given by vanadium, tungsten, chromium, and molybdenum on account of the lower specific gravity of the niobium as compared for instance with molybdenum and that of tantalum as compared with tungsten. A given weight of niobium, and of tantalum, therefore, having a greater volume will exert a greater influence. The oxide of molybdenum and tungsten, especially the Specification of Letters Patent.

Patented Apr. 5, 1921.

former, are more volatile than those of niobium and tantalum. In consequence of this, the elfect of niobium and tantalum is more permanent when the metal is heated on ac-' count of less volatilization of the oxids which are formed. Another advantage possessed by the niobium and tantalum is the greater afiinity for gases, such as hydrogen, than other metals used for hardening and toughening steel. The niobium and tantalum also combine with any nitrogen or oxygen which may be present, thus purifying the metal bath and rendering the resultant metal more uniform.

In incorporating the tantalum or niobium or both, these metals singly or together may be added directly to the steel bath or a ferro alloy containing either one or both may be added or, in case it is desired to produce a metal containing tungsten, molybdenum, chromium or vanadium, the desired percentages of these metals may be incorporated in the ferro alloy. These ferro alloys may be produced either by reducing the metals from the oxids of niobium or tantalum or both by means of carbon, a sufiicient quantity of iron being added toform a desired alloy. Another method is to reduce by means of carbon the niobium or tantalum directly from the ores columbite or tantalite, in a manner similar to that followed in the production of ferro tungsten. In high speed steel, as now manufactured, the tungsten averages from 12 to 20%. According to my invention if it. is desired to replace the tungsten entirely with niobium or tantalum, a less percentage of these singly or in combination may be used than the percentage of tungsten. For instance, in case of niobium the percentage may average from 6 to 12, while in the case of tantalum the percentage may run from. 8 to 16. If a combination is used the proper modification of these amounts will be obvious. In case all of the tungsten is not eliminated and it is desired to retain a certain percentage of the tungsten while having present either the niobium or tantalum in less quantities than when they are used without the tungsten, the proper percentages can be readily calculated or indeed these percentages may be determined readily by experimentation. For example, about 3 to 6% niobium may be used with 6 to 10% of tungsten or 4 to 8% tantalum may be used with 6 to 10% tungsten. When all three metals are utilized the niobium may run from 2 to 4%, the tantalum from 3 to 6%, and the tungsten from 4 to 8%.

Niobium and tantalum or both may be introduced into the steel by introducing theconcentrates and a suitable reducing agent just as is done in the production of tungsten steel. Another method is to introduce them in the form of a, ferro alloy produced either from the oxids or the ore, just as is in the production of ferro tungsten. Still another method which maybe used when it is desired to incorporate the other metals, such ashere- I inbefore referred to, is to combine the con centrates of niobium or tantalum with the concentrates of these other metals and then to throw the whole mixture into the steel bath. In the manufacture of ferro-tungsten and ferro-chrome and other ferro alloys of thisnature, the niobium or tantalum concentrate may be mixed with the concentrate of tungsten, molybdenum, chromium, etc., and incorporated with the ironto produce a ferro-tungsten, ferro-ch'rome, ferro-molybdenum, containing a certain percentage of niobium or tantalum; These products can be distributed assubstitutes for the present ferro alloys which are added to the bath in the roduction of these steels.

It wlllbe recognized that these are merely illustrations and that my invention, ashereinbefore stated, is not limited to any particular proportions of these metals, but comprises in its scope the useof niobium or tantalum or both in steel alone or combined with other alloying metals. In the claims I have used the expression metal of the niobium class to cover either tantalum or niobium.

Havin fully described m invention, what I c aim and desire to obtam by Letters Patent is; v

1. A steel containinga smallproportion of niobium. 1

2. .A steel containing a small proportion of niobium and tantalum.

3. Asteelcontai'ning a small proportion of niobium and at least one "other of the rarer metals ordinarily used for alloy steels. 4. A steel containing a small proportion of a metal of the niobium class and at least one otherfof the rarer metals ordinarily used in alloy steels.

'5. A steel containing a small proportion of a metal of the nioblum' class in combination with tungsten.

6. High speedsteel containing a small proportlon of a metal of the niobium class.

Iigh speed steel containing .a small I 7 proportlon of niobium.

8. High speed steel containing a small proportlon of niobium and tantalum. v

9. A high speed steel containing a small proportion of a metal of the niobium class and at least one other of the rarer metals ordinarily used in high speed steel.

10. High speed steel containing a small proportion of a metal of the niobium class in combination with tungsten. x

11. High speed steel containing a -small tungsten.

12. High speed steel containing av small proportion of niobium and tantalum in combination with tungsten.

13. A. steel containing niobium in the proportion of-three to twelve per Cent.

14;. A steel containing niobium and tantalum the proportion of three to six per cent. niobium, and four to eight per cent. tantalum.

15. A steel containing tungsten, niobium or tantalum, the niobium being in the proportion ofvthree to six per cent, and the tungsten in the proportionof six to ten per cent...

16. A steel containing tungsten, niobium and tantalum, the tungsten belngin the proportion offour to eight per cent, the niobium'two to four per cent, and the tantalum three to six per cent; 4

' v ALADAR PACZ.

' proportion of niobium in combination with