US2097179A - Alloy - Google Patents

Description

' P.......i ocszc, 1931 2,097,179

UNITED STATES PATENT OFFICE" .Anthony G. de Golyer, New Yorln-N. Y.

No Drawing. Application August 21, 1936,

Serial N0. 97,193

3 Claims 148-321) The present invention relates to a new and only brittle, but are so sensitive to various operuseful alloy and relates particularly toan alloy ating conditions as to greatly restrict the scope containing boron, tungsten, chromium and nickof usefulness. One of the greatest disadvantages el, which is characterized by being responsive "of such heretofore proposed compositions is that 5 to thermal treatment for the improvement of none of them are responsive to thermal treat- 5 physical properties. w ment for regulation of physical properties, and

An object of the present invention is to proconsequently physical properties and character-'- vide an alloy especially adapted for use as metal istics are governed entirely by the chemical comcutting tools, the cutting efficiency of which is position of the sintered or cast material.

superior to that of present known high speed My alloy may beused in the as-cast condition, 10 steels and other alloys. A further object is to orit may be forged or otherwise mechanically provide an alloy which is free from, or substan-- worked, I have found that both the cast and tially free from carbon and which is readily forged material are amenable to thermal treatamenable to thermal treatment, by means of ment. For example, cast bodies of this alloy which the hardness, tensile strength, cutting efmay have a hardness of from 50 to 60 on the 15 ficiency and other physical properties and char- Rockwell C. scale and by. subjecting the material acteristics may be accurately controlled over a to suitable thermal treatment, such as quenchcomparatively wide range. ing from a temperature higher than approxi- I have found through-experlmentthat by almately 1000 C., the hardness may be lowered to loying or otherwise intimately combining boron, an approximate range of from 40 to 4'7 Rockwell 20 tungsten, chromium and nickel within the range C. In this condition the bodies may be ground, of boron 0.50% to 2.75%, tungsten 5% to shaped or formed, as desired. The alloy may chromium 1% to 15%, and nickel substantially subsequently be submitted to a second thermal the balance, that I obtain metallic compositions treatment, such as heating to a temperature of 5 which possess in combination materially imless than 1000 C. for a period of one hour or 25 provedphysical properties compared to those of more, by which the hardness may be increased heretofore known alloys or compositions intended to from approximately 60 to 70 Rockwell C. for the cutting or working of metals. In the latter condition the alloy is especially Alloys of this invention may be used in the valuable for the cutting or mechanical working cast condition but approximate maximum values of a large number of metals and alloys, as well 30 of hardness, resistance to impact and certain as numerous non-metallic materials. An imother important physical properties can be deportant property of this alloy is that virtually all veloped only through thermal treatment, or of the maximum hardness, developed by thermal through mechanical working and subsequenttreatment, is retained when the alloy is subjectthermal treatment. Bodies of the alloys which ed to elevated temperatures, e. g. such as are 35 have been subjected to such treatment are pargenerated in the tip of a tool cutting metal at ticularly valuable for use as tools, dies and the high speed. Although the alloy has a high delike for the cutting or mechanical working of gree of hardness and resistance to abrasion by meta1s hot metal chips, especially after therma1 treat- Numerous metallic compositions have heretoment, it is remarkably resistant to failure from 40 fore been proposed as improvement onthe gensudden or repeated shock. Therefore, tools made erally known 18-4-1 type of tungsten-chromiumof the present alloy retain an efiicient cutting vanadium high speed tool steel, and while many edge for longer periods than other tools. of such compositions possess greater hardness The more important distinctive and valuable than such steel, all of them have disadvantages advantages are, apparently, due to the presence 45 which render them unsuitable for general appliof appreciable amounts of boron in the composication as metal cutting or forming tools. Sintion, in conjunction with theother essential comtered or semi-fused compositions containing ponent elements within the percentages specified principally carbides of tungsten, molybdenum or herein.

tantalum bonded with a relatively soft matrix I have found that molybdenum may be used 50 metal have a high degree of hardness, but are to supplant all or a portion of the tungsten of extremely brittle. Cast compositions of the types the'present alloy. Likewise, uranium may be heretofore proposed require the presence of at ,used in place of either tungsten or molybdenum. least 1.50% carbon to qualify as metal cutting Specific examples of compositions within the tools and, as is well known, such alloys are not scope of the present invention which I have 55 found well adapted for metal cutting tools, dies and the like are the following: boron 1.20%,

- 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 of higher percentages of this element make the alloy extremely brittle and subject to failure during cutting operations, and, also inhibits the desired and necessary re- 'actions during thermal treatment. Furthermore, the presence of appreciable amounts of carbon decreases the red hardness of the alloy, 1. e. hardness at temperatures of approximately 550 C. and higher. 1

By reason of the fact that the elements forming the essential components of the alloy of the present invention invariably are contaminated with other elements when produced in commercial quantities, the alloys of my invention usually contain insignificant amounts of one or more elements, such as manganese, silicon and aluminum, in the nature of impurities incidental to manufacture. The amount of such impurities should be restricted to percentages which are not effective on the physical properties or characteristics of the alloy, nor on the physical reactions during thermal treatment. I have found that the amount of any one of such incidental impurities should be restricted to percentages not exceeding 1%, and in many instances to materially lower percentages. The presence of larger amounts of suchimpurities, particularly silicon and aluminum, materially decreases the resistance of the alloy to failure under shock and impact during cutting operations, and, further, inhibits the desired physicalreactions during thermal treatment. Therefore, the presence of effective amounts of impurities, such as carbon, silicon and aluminum, act to appreciably lower the cutting efllciency and general value of the present alloy.

My investigations indicate that the preferred structure of a body of the present alloy. particularly after thermal treatment, 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 and other articles composed of this alloy may be operated eflloiently 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 comprises boron, chromium, and metal of the group tungsten, molybdenum and uranium within the percentage limits specified, with the remainder nickel except for ineffective amounts of impurities which may be present incidental to manufacture.

I claim:

1. An age hardened alloy containing boron 0.50% to 2.75%, metal from the group tungsten, molybdenum and uranium 5% to 25%, chromium 1% to 15%, the balance substantially nickel.

- 2. An age hardened alloy containing boron 0.50% to 2.75%, tungsten 5% to 25%, chromium 1% to 15%, the balance substantially nickel.

3. An age hardened alloy containing boron 0.50% to 2.75%, molybdenum 5% to 25%, chromium 1% to 15%, the balance substantially nickel.