US1998956A - Ferrous alloy - Google Patents

Description

Patented Apr. 23, 1935 I UNITED STATES PATENT-OFFICE FERBOUS ALLOY Joseph V. Emmons, Shaker Heights, Ohio, as-

signor to The Cleveland Twist Drill Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Original application December 22,

1934, Serial No. 758,754. Divided and this ap plication March 11, 1935, Serial No. 10,391

13 Claims. (01. 75-4) This application is a divisionof my co-pendcipal alloying element, and when thus added ing application Serial No. 758,754, filed Decemin amounts which bear a certain proportional reber 22, 1934. lationship to the amount of tungsten present,

This invention relates to ferrous alloys and has a powerful auxiliary effectuponsuch steel.

more particularly to alloy steels in which tung- Such results are considerably more pronounced 5 sten is employed as aprinclpal alloying constituthan those usually achieved by the addition of ent. More specifically, this invention relates to molybdenum to high tungsten steels in accordthat type of ferrous alloys or alloy steels which ance with the practices in the'prlor art. is employed in the form of cutting tools and It is a principal object of this invention, therewear-resisting parts and which type is commonly fore, to provide a ferrows alloy composition, or 10 referred to by those familiar with the art as an more particularly, a tool steel of the type in alloy tool steel. which tungsten is a principal alloying consti- As is well known to those familiar with the. tuent and to which there has also been added art, alloy tool steels have, in the past, been made a minor amount of molybdenum for its powerful 1:, with tungsten as the principal alloying constituauxiliary efiect, thus producing a steel which, cut and the types commonly known as high when used for purposes of cutting tool, wearspeed steels are at present the standard com resisting parts and the like, has performance mercial tool steels for high duty machining of characteristics equal to and in certain respects metallic substances. The tungsten high speed superior to those of comparable steels in the steel most widely used commercially at the presprior art.

ent time is essentially an alloy of carbon and It is a further object of my invention to provide iron with approximately 18% tungsten, 4% a high speed tool steel of the high tungsten type chromium and 1% vanadium. This standard type having cutting or wear-resisting properties suis commonly known as 18 -4l high speed perior to the cutting or wear-resisting properties steel. In addition, such steel contains minor of the standard 18--4-1 tungsten high speed 25 quantities of such alloying elements and impuritool steel. ties as manganese, silicon, copper, sulphur, phos- It is also an object of my invention toprovlde phorus, arsenic, tin, etc. Such elements as coa high speed toolsteel of the high tungsten type bait, nickel, uranium and tantalum are somesubstantially equal in cutting or wear-resisting times added to secure certain changes in the qualities to the standard 184--l high speed tool 30 properties of the steel. I steel but which contains a materially lesser In my previous U. S. Patent No. 1,937,334 is amount of the expensive ingredient tungsten.

disclosed the fact that a very satisfactory steel It is also an object of myinvention to provide capable of being satisfactorily used for the same a high speed tool steel of the type in which purposes for which 18-4-1 high speed steel has tungsten is the alloying element having the doini- 35 been used may be secured, if to a steel in which nating effect and which steel has a lower .it. is molybdenum is the principal alloying ingredigravity than comparable steels of this type known ent, minor amounts of tungsten are added and to the prior art.

. if the amount of such tungsten is present in a It is a further object of my invention to provide 40 defined proportional relationship to the amount high speed tool steels which may attain a higher 40 of molybdenum present. It has been explained degree of secondary hardness after hardening and that the unexpectedly desirable results secured tempering than is usual wit the standard by the addition of minor amounts of tungsten 184-1 type of steel. to a molybdenum steel as taught in my above It is still another object of my invention to proidentified patent is due to a powerful auxiliary vide steels having high secondary hardness and 45 effect which such minor amount of tungsten has also having, high values of strength and of plasupon the molybdenum content of the alloy. The ticity developed simultaneously by the same heat desirable results secured by the addition of such treatment so that said steels exhibit exceptional minor amounts of tungsten to a molybdenum toughness.

steel are greater than any results which would be Other objects of my invention will appear as the 50 expected upon the theory of equivalency of tungdescription proceeds.

sten and bolyb'ienum as taught in the prior'art. To the accomplishment of the foregoing and The present invention relates to the discovery related ends, said invention, then consists of the that molybdenum, when added to a ferrous means hereinafter fully described and particu- 5 alloy composition, in which tungsten is the prinlarly pointed out in the claims.

The following description sets forth in detail some approved combinations of ingredients embodying my invention, such disclosed means constituting however, but a few of the various forms in which the principle of the invention may be used.

The present invention relates, as previously indicated, to the discovery that certain minor amounts of molybdenum, as hereinafter more fully defined, when added to a ferrous alloy composition of the type in which tungsten is a principal alloying ingredient, have a powerful auxiliary alloying eflect thereon, considerably greater than any effect of molybdenum previously observed in such alloy compositions.

More specifically, this invention comprises the discovery-that in the class of alloy tool steels in which tungsten is the dominating alloying element, there is a definite relationship between tungsten and molybdenum which, if properly observed, produces unexpectedly favorable results.

This relationship is made effective by adding to such steels auxiliary molybdenum inamounts from about 12% to about 28% of the amount of tungsten present. Such additions have been found to greatly and unexpectedly increase the cutting and wearing quality of tools made from the steel.

The above given range of from about 12% to 28 for the ratio between the tungsten and molybdenum may be conveniently divided into the following narrower ranges, viz:-

Molybdenum from about 12% to about 15% of the tungsten present;

Molybdenum from above 15% to about 25% of the tungsten present;

Molybdenum from above 25% to about 28% of the tungsten present.

The previously defined range for the ratio between the two elements may be further divided in the following manner, viz:- V

- Molybdenum from about 12% to about 20% of the amount of tungsten present; and

Molybdenum from above.20% to about 28% of the amount of tungsten present.

In the ensuing description wherein will be found a disclosure of a large number of alloys, in which the above defined-proportional relationship between tungsten and molybdenum is maintained, it will be noted that there are certain groups of compositions which may be conveniently classified in the above defined manner.

The broad limits of composition within which this invention resides are as follows:

Carbon about 0.15% to about 1.60% Silicon a trace to about 3.00% Chromium about 3.25% to about 6.00% Tungsten about 8.00% to about 20.00% Vanadium none to about 6.00% Molybdenum about 0.96% to about 5.60% Cobalt none to about 16.00%

the remainder being substantially iron together with such other alloying elements and impurities as are sometimes found in this type of alloy composition.

A somewhat narrower range of compositions is as follows:

Carbon about 0.65% to about 0.90%

Silicon about 0.20% to about 2.20% Chromium about 3.37% to about 4.98% Tungsten about 10.32% to about 19.00% Vanadium about 0.45% to about 3.09% Molybdenum about 1.24% to about 5.32% Cobalt none to about 14.00%

the remainder being substantially iron together with such other alloying elements and impurities as are sometimes found in this type of alloy composition.

A still narrower range of composition is as follows:

the remainder being substantially iron together with such other alloying elements and impurities as are sometimes found in this type of alloy composition.

Specific examples of alloy compositions made in accordance with this invention and falling within the above defined ranges of compositions, as well as within the above-mentioned proportional relationship between tungsten and molybdenum are as follows:

Example N0.

M0 Ratio w Actual Per cent Per cent Per Per Per cent Per cent 4. 00

preciably, thus reducing the weight of steel r'e- I Attention is directed to the fact that in the foregoing table the various compositions are arranged in the order of the proportional relationship therein between molybdenum and tungsten. I

In the following table I include certain data in regard to the heat treatment and some of the physical properties of certain of the examples of the specific alloy compositions included in the quired to make a tool or other article of manuiacture.

From the foregoing description, it will be apparent that my invention relates not to the substitution of molybdenum for tungsten in high speed tool steels as has been suggested in certain instances in the prior art, but instead to the production of a new type of tungsten steel in which previous table a specific minor amount of molybdenum is used Tampering Maximum Maximum Plasticity at specific Hardness in Best hardrange [or secondary torsional maximum my"; in annefled Example number ening range maximum hardness obstrength obstrength in ma ed condition.

F. second served Rockserved degree of condition Rockwell hardness F well scale inch-pounds 1 twist l B scale 2270-2340 990-1140 66. 0 476 12a 8. 32 2310-2340 1040-1140 66. 3 457 I 34 v 8. 39 100-101 2270-2350 About 1040 8. 36 2270-2340 940-1 65. 3 442 50 8. 29 102-104 2290-2340 940-1140 66. 1 484 102 8. 38 94-99 2270-2340 940-1140 65. 2 431 38 8. 30 99-100 2270-2440 840-1040 65. 4 449 96 8. 32 99-100 2270-2310 990-1140 66. 5 429 29 8. 29 99-100 22%- 1040-1140 67. 7 454 45 8. 28 97-99 2270-2330 940-1090 66. 4 435 96 8. 21 2270-2330 940-1140 66. 9 446 56 8. 24 97-100 2310-2440 990-1140 65. 7 429 48 8. 40 97-88 2240-2310 940-1090 66. 6 449 45 8. 57 96-}01 2240-2310 940-1040 65. 4 418 47 8. 35 101- 02 $50-$10 940-1190 67. 8 452 58 8. 99-100v 2270-2330 1040-1140 8. 99-101 2240-2310 940-1040 64. 4. 429 67 8. 33 99-100 2240-2310 940-1090 64. 5 446 94 8. 25 98 2240-2270 940-1040 62.4 8.'% 100-104 2240-2340 940-1040 66. 2 453 62 8. 39 100-102 1 For a description oi the method of determing these properties refer to Proceedings American Society for Testing Materials" vol. 31

Part II (1961), Page 47.

Certain maximum values, such as hardness. given in the foregoing table, are those which have been observed; however, it is possible that higher values may be attainable by diflferent heat treatments.

While the above values, indicating the best hardening and tempering ranges, are the results of actual observations, it is recognized that they are a, matter of opinion only and for specific purposes, desirable. heat treatment might be found outside these values.

It will be observed that the specific gravities oi! the examples listed in the above table are materially lower than those of the 18--4-1 type of high speed steel, the specific gravity of which is generally in excess of 8.60.

Particular attention is called to Examples No. 8 and 14. These steels showed outstanding. cutting quality when used as drills, their drillingperi'ormance definitely exceeding that of the drills made of l8--41 high speed steel with which they were compared. I

Particular attention is also called to the high secondary hardness developed by Examples Nos. 3,

6, 9, 10, 11, 12, 14, 16, 23. Hardnesses in excess of Rockwell C 66 are regarded as beungabove those ordinarily developed in the 18-4-1 type-oi high speed steel. 7

Attention is alsocalled' to the. high tempering range which is recorded for Example 16. The values of 940110 1190 indicate'a bropd range and a l high order of red-hardness.

The abnormally high plasticiiy values shown by Examples 2, 6, 8,11 and 19 are caused by the peculiarity that the maximum strength of the steel is developed at a tempering temperature so low that it falls within the range of high plasticity.

The high silicon contents of many of the above examplesare round to producea very sound,

thoroughly .deoxidized steel. High silicon alto reduces the specific gravity of the steel quite apfor its powerful auxiliary eflect in increasing the cutting and wearing qualities of such steel. By the addition 0! the auxiliary quantities of molybdenum in the above defined specific ratio to the amount oi'tungsten'present, II have been able to produce a high speed steel of the tungsten type having cutting properties better than those of the molybdenum-free tungsten steels of the prior art and also better than certain other molybdenum containing tungsten steels oi the prior art which lie outside the above specified range of ratios of molybdenum to tungsten and with which comparisons have been made- A wide variety of heat treatments may ployed in connection with the above mentioned steels, including among others hardening, tempering, carburizing,- and nitriding, for the purpose be deposited as weld metal ior'the purpou of producing localized cutting or wear-resisting portions of an article of manufacture.

Steels of some of the above compositions, due to their great strength and toughness, are suitable for use as supporting and auxiliary wearing parts be emin composite tools, employing primary cutting I I edges or wearing surfaces formed on elements of hard non-ferrous metallic compositions.

Exceptional hardness is obtainable by appropriate heat treatment of certain of the abovementioned compositions. 7 tools particularly suitable for machining materials of greater hardness than those at present considered machinable by steels oi the 18--4--1 high speed steel type.

Steels made m accordance with this invention may be produced with extreme hardness and a low degree of toughness. Suchsteel may be uti- This makes possible 1 at temperatures approaching the melting point,

makes possible the production therefrom of certain articles of manufacture by various processes requiring a high degree of plastic flow, such as die forging, pressing and extruding.

As is well known to those familiar with the art, any specification for a particular alloying composition must permit of certain variations due to the fact that in making up the steel it is extremely diiilcult, if not impossible, to commercially produce a composition exactly like a given specification. It is to be understood, therefore, that throughout the description and claims where .I have used figures to denote definite amounts and ranges, such amounts and ranges are to be construed to include the range of variations usually permissible in making up steel to given specifications.

It is understood that in the composition specified therein, minor amounts of other alloying elements and'impurities such as manganese, nickel,

titanium, tantalum, uranium, copper, aluminum,

sulphur, phosphorus, arsenic, tin, etc., may be included and when the phrase the balance being substantially all iron is used, it is intended to include minor amounts of such elements.

8.00% to about 20.00%;

Other forms may be employed embodying the features of my invention instead of the one here explained, change being made in the composition, provided the elements in the amounts stated by any of the following claims or the equivalent of such stated elements be employed.

I therefore particularly point out and distinctly claim as my invention:-

1. A ferrous alloy comprising: carbon from about 0.15% to about 1.60%; chromium from about 3.25% to about 6.00% tungsten from about molybdenum from twelve and one-half per cent to twenty-eight per cent of the amount of tungsten present; silicon from a substantial amount to about 3.00%; vanadium from a substantial amount to about 6.00% cobalt from a substantial amount to about 16.00%; and the remainder being substantially all iron.

2. A ferrous alloy comprising; carbon from about 0.15% to about 1.60%; chromium from about 3.25% to about 6.00%; tungsten from about to about 19.00%; molybdenum from twelve and one-half per cent to twenty-eight per cent of the amount of tungsten present; silicon from a substantial amount to about 3.00%; vanadium from a substantial amount to about 6.00%; cobalt from a substantial amount to about 16.00%; and the remainder being substantially all iron. I

3. A ferrous alloy comprising: carbon from about 0.15% to about 1.60%; chromium from about 3.25% to about 6.00%; tungsten from about 11.04% to about 16.50%; molybdenum from twelve and one-half per cent to twenty-eight per "cent of the amount of tungsten present; silicon from a substantial amount to about 3.00%; vanadium from a substantial amount to about 6.00% cobalt from a substantial amount to about 16.00%; and the remainder being substantially all iron.

4. A ferrous alloy comprising: carbon fromabout 0.15% to about 1.60%; chromium from about 3.25% to about 6.00% tungsten from about 8.00% to about 20.00%; molybdenum from twelve and one-half per cent to fifteen per cent of the amount of tungsten present; silicon from a substantial amount to about 3.00%; vanadium from a substantial amount to about 6.00%; cohalt from a substantial amount to about 16.00%; and the remainder being substantially all iron.

5. A ferrous alloy comprising; carbon from about 0.65% to about 0.90%; chromium from about 3.37% to about 4.98%; tungsten from about 10.32% to about 19.00%; molybdenum from twelve and one-half per cent to fifteen per cent of the amount of tungsten present; silicon from about 0.20% to about 2.20%; vanadium from about 0.45% to about 3.09%; cobalt from a substantial amount to about 14.00%; and the remainder being substantially all iron.

6. A ferrous alloy comprising: carbon from about 0.65% to about 0.85%; chromium from about 3.42% to about 4.73% tungsten from about 11.04% to about 16.50%; molybdenum from twelve and one-half per cent to fifteen per cent of the amount of tungsten present; silicon from about 0.27% to about 1.00%; vanadium from about 0.68% to about 2.46%; cobalt from a substantial amount to about 12.00%; and the remainder being substantially all iron.

7. A ferrous alloy comprising: carbon from about 0.15% to about 1.60%; chromium from about 3.25% to about 6.00%; tungsten from about 8.00% to about 20.00%; molybdenum from fifteen per cent to twenty per cent of the amount of tungsten present; silicon from a substantial amount to about 3.00%; vanadium from a substantial amount to about 6.00%; cobalt from a substantial amount to about 16.00%; and the remainder being substantially all iron.

8. A ferrous alloy comprising: carbon from about 0.65% to about 0.90%; chromium from about 3.37 %to about 4.98%; tungsten from about 10.32% to about 19.00%; molybdenum from fifteen per cent to twenty per cent of the amount of tungsten present; silicon from about 0.20% to about 2.20%; vanadium from about 0.45% to about 3.09%; cobalt from a substantial amount to about 14.00%; and the remainder being sub stantially all iron.

9. A ferrous alloy comprising: carbon from about 0.65% to about 0.85%; chromium from about 3.42% to about 4.73%; tungsten from about 11.04% to about 16.50%; molybdenum from fifteen per cent to twenty per cent of the amount of tungsten present; silicon from about 0.27% to about 1.00%; vanadium from about 0.68% to about 2.46%; cobalt from a substantial amount to about 12.00%; and the remainder being substantially all iron.

10. A ferrous alloy comprising: carbon from about 0.15% to about 1.60%; chromium from about 3.25% to about 6.00%; tungsten from about 8.00% to about 20.00%; molybdenum from twenty per cent to twenty-eight per cent of the amount of tungsten present; silicon from a substantial amount to about 3.00%; vanadium from a substantial amount to about 6.00%; cobalt from a substantial amount to about 16.00%; and the remainder being substantially all iron.

11. A.ferrous alloy comprising: carbon from about 0.65% to about 0.90%; chromium from about 3.37% to about 4.98%; tungsten from about 10.32% to about 19.00%; molybdenum from twenty per cent to twenty-eight per cent of the amount of tungsten present; silicon from about 0.20% to about 2.20%; vanadium from about 0.45% to about 3.09%; cobalt from a substantial amount to about 14.00%; and the remainder being substantially all iron.

12. A ferrous alloy comprising: carbon from about 0.65% to about 0.85%; chromium from about 3.42% to about 4.73% ;'tungsten from about 11.04% to about 16.50%; molybdenum from twenty per cent to twenty-eight per cent of the amount of tungsten present; silicon from about 0.27% to about 1.00%; vanadiumfrom about 0.68% to about 2.46%; cobalt from a substantial amount to about 12.00%; and the remainder being substantially all iron.

13. A tool formed of a ferrous alloy comprising: carbon from about 0.15% to about 1.60%; chromium from about 3.25% to about 6.00%; tungsten from about 8.00% to about 20.00%; molybdenum from twelve and one-half per cent to twenty-eight per cent of the amount of tungsten present; silicon from a substantial amount to about 3.00%; vanadium from a substantial amount to about 6.00%; cobalt from a substantial amount to about 16.00%; and the remainder being substantially all iron.

JOSEPH V. EMMONS.