US2397222A - Beryllium copper alloy steels and articles of manufacture produced therefrom - Google Patents

Description

Patented Mar. 26, 1946 BEBYLLIUM COPPER ALLOY STEELS AND ARTICLES OF MANUFACTURE PRODUCED THEBEFBOM Enrique G. 'Iouceda, Loudonville, and Ralph P. De Vries, Menands, N. Y., aasignors to Allegheny Ludlum Steel Corporation, a corporation of Pennsylvania No Drawing. Application July 28, 1942, Serial No. 452,640

9 Claims. (Cl. 75-124) Our present invention relates to beryllium-containing alloy steels and to cast, forged and rolled articles of manufacture composed thereof.

It has been difficult in the past to produce alloy steels characterized both by high strength and by good ductility especially in conjunction with a fluidity point such that castings can be made by various procedures, In particular, alloy steels with a fluidity point at or below 2500 F. in which melting occurs through a short range of temperatures have been much desired but not heretofore realized although recasting can best be carried out under such conditions. These and other considerations have thus given rise to problems to the solution of which our present invention is directed.

One of the objects of our present invention, therefore, is to produce beryllium alloy steels which possess desirable physical properties and ture fabricated therefrom as by casting, forging or rolling operations have unusual and unexepected properties making them useful for a variety of purposes and supplying a need not heretofore satisfied so far as we are aware. Our new alloy steels are particularly noteworthy in that they contain an amount of beryllium which may range from a very minute amount in the neighborhood of .05% to the appreciable quantity of about .5%. These beryllium alloy steels contain an amount of copper ranging from about .5-8%, an amount of silicon ranging from about .5-4.5% and an amount of molybdenum ranging from about .15-2.5%. These steels likewise contain carbon and the content of this element may range from approximately .08-1.5%. Manganese may always be present in these alloys but the amount thereof should preferably be limited to a maximum of approximately 175%. The usual metalwhich can be readily fabricated into a variety :0 ioids sulphur and phosphorus are present in the of useful products.

Another object of our invention resides in the production of articles of manufacture by casting,

forging and rolling them from beryllium alloy steels which combine high strength and good as Reierenccisflrstmade toTable I:

ductility with unusual fluidity.

A further object of our invention is to produce alloy steels containing a small amount of beryllium ranging from about .05-.5% in combination with the other elements hereinafter specified and which are not only themselves possessed. of unusual physical properties but which make possible the fabrication of various articles of manufacture therefrom which also possess new and valuable properties.

Other and further objects and advantages will be understood by those skilled in this art or will be apparent or pointed out hereinafter.

Our present invention is predicated upon the discovery that alloy steels composed of the constituents hereinafter specified in approximately the amounts set forth and articles of manufacnormal amounts found in steels. The physical and metallurgical nature and properties of these alloy steels are best set forth byway of examples, a number of which follows.

Table l A No. Mn Cu ssssssssesas lessees-lessees l me: than Steels 51-307, i i-30d, A5309 and A-tlii illustrate the influence of varying amounts of beryllium on the fluidity point or our new alloy steels in melting for recasting are obtained when these operations take place under reducing conditions.

Reference is next had to Table II:

Table II Transverse test A No. Heat treatment Bend Unnotchczi impact Bend Rockwell F, p. s. i.

Degrees Degrees 1650" I oil 750- 42 285, 009 7 55 ft.--lbsl 33 230,000 4 26 234,000 10 55 278,000 1 276,000 2 245, 600 ll 28 260,000 1 261,000 2 28 228, 000 258,000 2 32 220, 000 4 26 242,000 23 51 282,000 1 97B 193, 000 12 92? 168, 000 23 328 ft.1bs 13 26 240,000 6 1600 F. oil 760 53 287, (100 0 1550 F. oil 760 51 483,000 0 Machined 1 rounds" d0 225,000 0 J,

F=flber stress on extreme fiber in pounds per square inch.

and by comparing the same in Table I it will be noted that composition i i-308 with a beryllium content of 3% had the lowest fluidity point (2475 F.). I'herefore, it will be appreciated that, the balance of the composition being constant, the amount of beryllium employed must be adjusted so that a clean-cut fluidity point can be secured which is at or below 2500 F., fluidity '40 points above that value being deemed unsatisfactory. While composition A-3l0 containing .l% beryllium has a fluidity point above 2500 F., nevertheless, this amount of beryllium is well within our invention because for other compositions its fluidity point is adequately low. For example, in composition A-299, which contains .11% beryllium, the fluidity point is 2450 F., an entirely satisfactory value, and it will be further noted in connection with this composition that as compared with compositions A-'-307-A-310, inclusive, it contained more copper and less sili- COD. compositions A-330 and A-295 contain molybdenum. While these molybdenum-containing compositions have satisfactory fluidity points and while they come directly within the purview of our present invention, nevertheless, we wish it understood that molybdenum is an optional 'rather than an essential component and when employed serves the purpose of increasing the strength of these already high strength alloy steels. Composition A-331 demonstrates also that the use of .1% beryllium makes it possible to secure a satisfactory fluidity point and this composition is particularly characterized by a higher carbon content than the other steels in this table.

These facts will inform the metallurgist as to the importance of adjusting the entire composition and will teach how to avoid the production of steels which melt through a comparatively long mushy range. This, in particular, is extremely important in recasting and in this connection we wish to point out that the best results Some of the mechanical properties of our new alloy steels in the as cast condition are set forth in Table II which, for most of the compositions included in Table I, sets forth the transverse strengths which can be obtained and also the ductility in terms of degrees of bend in the transverse tests from the various heat treatments designated. While it so happens that the highest heat treatment designated in Table II is 1750 F. this is purely due to the fact that the results It will be further noted from Table I that included are illustrative and not limitative, because we have found that our new alloy steels may be treated at temperatures as high as 2150 F. and that they can then be drawn back to obtain a wide range of properties depending upon the intended purpose. Even when heat treated from 2150 F. our alloy steels have an extremely fine, silky fracture equal to that of the best cast alloy steel practice. Table II shows that these steels may be heat treated to impart thereto a hardness as low as 9'7 Ball Rockwell, when quenched and drawn, and up to 60 Cone Rockwell when quenched from the low temperature of about 1550'F. followed by drawing at the comparatively low temperature of 750 F.

Except for compositions A329--A-331, inclusive, all tests were made on bar stock in the as cast condition with such imperfections as ordinarily occur on the surface of such castings and in some instances these imperfections led to premature rupture. In the case of compositions A-329 to A-331 such were all machined to 1" rounds. The unusually high strength values of steel A-330 showed that these steels are very resistant to the shearing action of the transverse test and this in turn means that they are extremely good in the cast state to resist rupture such as that produced from suddenly applied stress.

That these steels forge and roll well to any size or shape that can be commercially produced by conventional forging or 'rolling operations is illustrated by Table III, which follows:

Table III ngo 01 M0 B8 5.01: 222. 3:50 .202.

DRAW TEMP. 750 F.

DRAW TEMP. 050 F.

DRAW TEMP. 1100* F.

DRAW TEMP. 750 F.

DRAW TEMP. 050 r.

140,000 157,500 182,000 120,500 10.0 20.5 ass DRAW TEMP. 1100" F.

DEAW TEMP. 750 F.

DRAW TEMP. 250 F.

DRAW TEMP. 1100 F.

Non:

P. L.-proportional limit. Prod-stress to produce .0002 set. Y. P.-yield point by dividers. '1. 8.-te11silc strength,

In this table we show the tensile properties obtained on three rolled steels, two of which contain beryllium and respond to our invention and the third of which contains no beryllium, being included for comparative purposes. The values enumerated in Table 111 show a definite superiority for the beryllium-containing steels. They also show that to some extent at least beryllium may constitute or be considered as a replacement of part of the silicon content, constituting a definite contribution to the strength of the steel and at the same time increasing the ductility of the steel as will be appreciated from the elongation and reduction of area. set forth.

Further reference is bad to Table IV, which follows:

Table IV Yield Tensile Elo Red. f 0 Si Mn Be M0 Cu 1 State point, will, 111111011 10102510 area.

p. a. i. p. a. i. in 2" percent A-307 0.63 3.25 0.60 0.20 1.50 A! cast I500 Foildrawn750F--- 88,000 2.0 4.0 10-309-... .48 3.25 .50 .40 1.60 do 01,001 1.0 2.1 21-310..-- .54 3.25 .50 .10 1.50 (in 05,000 3.0 7.1 A-414..- .15 2.00 .50 .10 1.00 1700* F. oil drawn 750 F. 1% hrs. 101,000 7.5 13.5

I'- A416...- 18 2.00 .50 .5 1.00 170(1); F. 011 drawnl750 F. 2 hrs. 106,)0 0. 6 12. 4

a A416..-- .26 2.00 10 6 1.00 (1); F. 011 drawn 760 F. 1} hi:- MM 3.0 15. 6

I A206.... .45 1.60 .10 .6 2.00 1500 F. 011 drawn 950. 185,000 1.0

From the foregoing it will thus be understood that our invention involves the introduction of about .05-.5% beryllium into copper, silicon steels, manganese ordinarily being present up to 35% and molybdenum optionally present in the amount heretofore specified. These alloy steels are noteworthy for their exceptional properties and characteristics and they constitute valuable additions to the alloy steel art. For most purposes the amount of beryllium may be in the lower half of the range set forth and for rolled and forged steels need not exceed approximately 25% although more may be used. For casting purposes where the lowest fluidity points are desired or required the beryllium content may run somewhat higher, for example, about .3%. The foregoing is, however, to be considered as illustrative and not as restrictive and within the terms of the appended claims other and further additions, omissions, substitutions and modifications may be made without departing'from the spirit and scope of our invention.

Having thus described our invention, what we claim as new and desire to secure as Letters Patent are:

1. An alloy steel containing as its principal alloying constituents, carbon from about 0.08% to about 1.50%, silicon in the neighborhood of 0.5% to 4.5%, copper from about 1% to about 8% and beryllium from about 0.10% to about 0.50% and characterized by low melting point and high physical properties in the as cast or hot worked condition.

2. An alloy steel containing as its principal constituents carbon from about 0.30% to about 1.00%, silicon from about 1.50% to about 3.25%, copper from about 1.25% to about 6.00% and beryllium from about 0.10% to about 0.50% and characterized by low melting point and high physicals in the as cast or hot worked condition.

3. An alloy steel having a comparatively sharp fluidity point ranging from about 2450 F. up to and including, but not exceeding, about 2500 F. and composed of carbon within the range including from about 0.08% to about 1.50%, silicon within the range including from about 0.50% to about 4.50%, copper within the range including from about 0.50% to about 8.00%, beryllium within the range including from about 0.05% to about 0.50% and molybdenum within the range.

including from about 0.15% to about 2.50% and the remainder, except for usual impurities in common amounts, substantially all iron.

4. An alloy steel containing as its principal alloying constituents carbon within the range including from about 0.08% to about 1.50%, copper within the range including from about 0.50% to about 8.00%, silicon within the range including from about 0.50% to about 4.50% and beryllium within the range including from about 0.05% to about 0.50%, a small amount of manganese in an amount not exceeding about 0.75% and the remainder substantially iron and characterized by having a fluidity point below 2500 F.

5. An alloysteel having a comparatively shar fluidity point ranging from about 2450 F. and

up to and including, but not exceeding about 2500 F. and, in addition to iron and the usual impurities in common amounts, consisting of carbon within the range including from about 0.30% to about 1.50%, copper within the range including from about 1.00% to about 6.00%, beryllium within the range including from about 0.10% to about 0.40%, silicon within the range including from about 1.50% to about 3.50% and not more than about 0.75%. manganese.

6. An alloy steel having a fluidity point not in excess of 2500 F. and characterized by good ductility and transverse strength in the cast state and consisting of carbon within the range including from about 0.40% to about 1.00%, copper within the range including from about 1.50% to about 6.00%, beryllium within the range including from about 0.10% to about 0.30%, silicon within the range including from about 1.50% to about 3.00%, not more than 0.75% manganese with the remainder, except for usual impurities in common amounts, substantially all iron.

7. Alloy steel having the composition defined in claim 3 and in which there has been incorporated a small amount of manganese not in excess of approximately .7 5%.

8. An article of manufacture composed of alloy steel as defined in claim 3 and characterized by good transverse strength and ductility after quenching from a relatively low temperature followed by drawing back at not over about 750 F.

9. A beryllium alloy steel casting characterized by a fluidity point not in excess of 2500 F. and having good tensile strength coupled with good ductility, said casting being produced from alloy steel of the composition defined in claim 3.

ENRIQUE G. TOUCEDA. RALPH P. DE VRIES.