US2126747A - Alloy - Google Patents

Description

Patented Aug. is, 1938 k ,PATE

NT OFFICE ALLOY Anthony G. de Golyer, New York, N. Y.

No Drawing.

3 Claims.

The present invention relates to a new and useful alloy and relates particularly to an alloy containing boron, tungsten; chromium, vanadium, zirconium and nickel, which is character 5 ized by being responsive to thermal treatment for'the improvement of physical properties.

Y An object of the present invention is to provide an alloy especially adapted for use as metal cutting tools; the cutting eiiiciency of which is superior to that of present known high speed steels and other alloys. A further object is provide an alloy which is free from, or substantially free from carbon and which isreadil-y amenable to thermal treatment, by means of which the hardness, tensile strength, cutting ef- I ficiency and other physical properties and characteristics may be accurately controlled over a comparatively wide range.

. I have found through experiment that byalloying or otherwise intimately combining boron, tungsten, vanadium, chromium, zirconium and nickel within the range of boron 0.50% to 3%,

tungsten 5% to 30%, vanadium 1% to 8%, zir-.

'conium 0.25% to 5%,.chromium 1% to and 25 nickel substantially the balance, I obtain metallic compositions which poses in combination materially improved physical properties compared to those of heretofore known alloys or compositions intended for the cutting or working of metals.

Alloys of this invention may be used in the cast condition but approximate maximum values of hardness, resistance to impact and certain other important physical properties can, be developed 5 only through thermal treatment, or through mechanical working and subsequent thermal treatment. Bodies of the alloys which havebeen subjected to such treatment are particularly valuable for use as tools, dies and the like for the 40 cutting or mechanical working of metals. Numerous metallic compositions have heretofore been proposed as improvement on the generally known 18-4-1 type of tungsten-chromiumvanadium high speedtool steel, and while many such compositions possess greater hardness thansuch steel, all of them have disadvantages which render them unsuitable for general application as metal cutting or forming tools. Compositions containing principally carbides of tungsten, mol'ybdenum or tantalum bonded: with a relatively soft matrix metal have a high degree of hard:

ness, but are extremely brittle. Cast compositions of-the typesheretofore proposed requirethe presence of at least 1.50% carbon to qualify 4 u as metal cutting tools and, as is well" known, such Application September 3, 1936, Serial No. 99,243

alloys are not only brittle, but are so sensitive to various operatingconditions as to greatly restrict the scope of usefulness. One of the greatest disadvantages of such heretofore proposed compositions is that none of them 'are responsive to thermal treatment for regulation of physical properties, and consequently physical properties and characteristics are governed entirelyby the chemical composition of the sintered or cast material.

My alloy may be used in the as-cast condition, or it may be forged or otherwise mechanically worked. In either case I prefer to subject the alloy to thermal treatmentbefore using it as a cutting tool or die. Both the cast and forged material are equally amenable to thermal treatment. For example, cast bodies of this alloy may have a hardness of from-50 to on the Rockwell C. scaleand by subjecting thematerial to suitable thermal treatment, such as quenching from 0 ly 60 to Rockwell C. In the latter condition the alloy is especially valuable for the cutting or mechanical working of a large number of metals and alloys, as well as numerous non-metallic vis that virtually all of the maximum hardness, developed by thermal treatment, is retained when the alloy is subjected to elevated temperatures, e. g. such as are generated in the tip of stool cutting metal at high speed. Although the alloy has a high degree of hardness and resistance to abrasion by hot metal chips, especially after thermal treatment, it is remarkably resistant to failure from sudden or repeated shock. Therefore. tools made of the present alloy retain an emcient cutting edge for longer periods than other tools. The more important distinctive and valuable advantages are, apparently, due to the presence of appreciable amounts of boron in the composition, in conjunction with the otheressential component elements within the percentages specified herein.

I have found that molybdenum may be used to supplant all or a portion of the tungsten oi the materials. An important property of this alloy 3 19.5%. Vanadium 4%, chromium 4%, zirconium 0.80%, nickel balance; boron 1.65%, molybdenum.

l3%, vanadium 3.5%, chromium 3.5%, zirconium 3.75%, nickel balance; boron 1.70% tungsten 5% molybdenum vanadium 5%, chromium 8%, zirconium 4.6%, nickel balance; boron 1.10%, molybdenum 12%, vanadium 6%, chromium 7%, zirconium 1.75%, nickel balance.

An objective of the present invention is to provide alloys having high hardness, high resistance to shock and impact, advantageous metal cutting properties, etc., which are free or substantially free from carbon, and thus eliminate all of the serious disadvantages associated with carbon containing non-ferrous alloys or compositions intended for metal cutting tools. Although I prefer to have the alloys of this invention entirely free from carbon, in many instances I have found carbon present in the nature of an impurity incidental to manufacture. It is important to restrict the amount of carbon so present to a maximum of about 0.15%, as I have found that the presence or higher percentages of this element make the alloy extremely brittle and subject to failure during cutting operations, and, greatly retards or entirely prevents the desired and necessary reactions during thermal treatment. Furthermore, the presence of appreciable amounts of carbon decreases the red hardness of the alloy, i. e. hardness at temperaturm of approximately 550 C. and higher.

By reason of the iact that the elements forming the essential components of the alloy of the present invention invariably are contaminated with other elements whenproduced in commercial quantities, the alloys of my invention usually contain insignificant amounts of one or more elements in the nature of impurities incidental to manufacture. Because of the fact that the maximum values of physical properties of thepresent alloy can be developed only through thermal treatment, it is essential that the amount of such incidental impurities present be limited to percentages which will not be efiective in retarding, or entirely preventing the necessary physical reactions during thermal treatment. the percentages of such impurities should also be restricted to amounts which will not be eiiective on the physical properties or characteristics of the alloy either before or after.

thermal treatment.

I have found that the most harmful impurities commonly present, in addition to carbon, are silicon and aluminum. The presence of either of. these elements in amounts greater than approximately 1% renders the alloyoi the present invention entirely unsuitable for thermal treatcomponents tungsten mium 1% to 25%, the

ment bymeans of which the hardness, tensile strength and impact resistance and other properties may be accurately controlled. One of the chief disadvantagesoi silicon and aluminum is that these elements apparently form chemical compounds with one or more or the essential of the present alloy,'and such compounds are not only hard, impact resistance, but are virtually insoluble in the solid composition during thermal treatment.

' It will be apparent, therefore, that the presence of eifective amounts of impurities, such as carbon, silicon and aluminum, materially change the character of the alloy through rendering it not amenable to thermal treatment.

My investigations indicate that the preferred structure of a body of the present alloy is produced only by means of thermal treatment, 'and that this comprises at least two principal constituents: one, a relatively hard intermetallic compound of boron with one or more of the other essential components; and, second, a solid solution of two or more of the essential components which has a lower degree of hardness and functions as a matrix. In some instances the structure will contain a third constituent in the nature of an eutectoid. The ratio of the constituents and the ratio of particle size in any particular body of the alloy may be accurately controlled and fixed .over a wide range by means of thermal treatment, or mechanical working and subsequent thermal treatment.

By reason of the combined advantageous physical properties possessed by the alloy of the present invention, tools andother articles composed of this alloy may be operated efllciently and economically under conditions which are impossible or uneconomical with tools or articles composed of heretofore known alloys or metallic compositions.

By the term the balance substantially nickel in the foregoing and in the following claims, I intend that the alloy of the present invention brittle and lacking in.

comprises boron, vanadium, zirconium, chromium and metal of the group tungsten, molybdenum and uranium, within the percentage limits specifled, with the remainder nickel except for ineffective amounts of impurities which may be present incidental to manufacture, as hereinbefore explained.

I claim:

1. A precipitation hardened alloy containing boron 0.50% to 3%, metal from the group tungsten, molybdenum and uranium 5% to 30%, vanadium 1% to 8%, zirconium 0.25% to 5%, chromium 1% to 25%, the balance'nickel.

2. A precipitation hardened alloy containing boron 0.50% to 3%, tungsten 5% to 30%, vanadium 1% to 8%, zirconium 0.25% to 5%, chromium 1% to 25%, the balance nickel.

3. A precipitation hardenedj alloy containing boron 0.50% to 3%. molybdenum 5% to 30%, vanadium 1% to 8%, zirconium 0.25% to 5%, chrobalance nickel.

ANTHONY G. D! GOLYER. 65