US2329483A - Bearing - Google Patents

Description

- Sept 14, 194-3. I P. E. QUENEAU ET AL 2,329,483

BEARING Original Filed May 27, 195 B 6 1. J 1 lat- .2.

NICKEL flLLo) PHOSPHOE B ROIVZE NICKEL ALLOY 1 N VE N TORS P1704 ET/E/V/YZ; ua-A0970 BYMMMW ATTORNEY.

Patented Sept. 14, 1943 UNITED STATES PATENT OFFICE BEARING Paul Etienne Queneau. Copper Cliff, Ontario,

Canada,

and

William Alvin Mudge, NcwYork,

N. Y., assignors to The International Nickel Company, Inc., New York, N. Y., a corporation of Delaware Original application May 27, 1938, Serial No. 210,370. Divided and this application February 5, 1941, Serial No. 377,428

, bearing (anti-friction) alloys containing principally lead, tin, antimony, copper, etc., but these have only a moderate resistance to certain types of corrosion and were generally soft. Usually these alloys possessed low melting points and low resistance to high temperature. Other hearing metals, such as bronze, lead-copper, or hard lead type have fulfilled some of the requirements of hardness and strength, but do not satisfy the most exacting corrosion-resisting requirements, particularly of sea water corrosion. Furthermore, good and adequate lubrication is necessary at all times. Case hardened steels have relatively good anti-galling properties and very high strength and hardness, but have little or no' resistance to corrosion. A malleable, high strength metal or alloy having good resistance to corrosion in most media and good anti-galling or anti-friction properties when used for rolling and/or sliding friction has not been commercially available. The art has been confronted with a problem requiring the production or treatment of alloys having relatively high tensile strength, such as about 100 or 140 to 160,000 pounds per square inch tensile strength with a minimum of per cent elongation, having excellent corrosion resistance to salt water and certain other agents-operating without galling under sliding and rolling friction, and being self-lubricating. In connection with the use of alloys of the aluminum-copper-nickel series. described in the U. S. Patent No. 1,572,744 to Merica and the U. S. Patents Nos. 1,755,554, 1,755,555, 1,755,556 and 1,755,557 to Mudge, under conditions where anti-galling is required, it has been customary in the past to treat the surface by wiping a very thin layer of tin or solder Adequate. and effective anchorage for the coatimproved anti-friction and anti-galling structure having high strength and corrosion resistance.

It is an object of the present invention to provide a new anti-friction and anti-galling bearing alloy characterized by good resistance to corrosion and the ability to operate under conditions of sliding and/or rubbing friction without failure through galling or seizing.

It is another object of the present invention to provide an improved composite anti-friction and anti-galling structure of high strength and good resistance to corrosion. Other objects and advantages will become ap parent from the following description taken in conjunction with the accompanying drawing, in which:

Figs. 1 and 2 are views representing photomicragraphs of the present improved anti-friction and anti-galling structure illustrating desirable types of bearing surfaces;

Fig. 3 represents a photomicrograph of a cross section of an improved anti-friction and anti-galling structure showing ,mountains or projections on the roughened, face of the underlying base or foundation stratum peeping thriough the applied layer of anti-friction metal; an

Fig. 4 is similar to Fig. 3 and illustrates schematically a cross section of an embodiment of the invention employing a plurality of layers of metal, the first or intermediate layer acting as a. bonding layer.

Broadly stated the bearng contemplated by the present invention *comprisesa layer of antifriction metal or alloy applied to the bearing face of a metal base to form a composite material.

ing is obtained by roughening the bearing face of the base to provide hills or projections separated by valleys or depressions. In the finished bearing the bearing surface comprises tops of the hills as islands of harder material surrounded thereon. This was satisfactory in service only as long as the tin remained intact. However, since the tin or the anti-friction (layer) metal was only in mechanical contact with the underlying by the layer of softer anti-friction metal in the valleys or depressions. The layer metal and the base metal are preferably difi'used into each other by heat treatment. As a result, a novel and efficient bond is produced between the layer and the base materials and the bearing combines the hardness and resistance to corrosion of the base metal with the anti-galling properties of the layer metal. Furthermore, the bonding provides a means of keeping this layer intact with the base so that it will not strip or wear off in service as usually occurred heretofore in the cases of the conventional wiped tin layer.

Processes of roughening the base, of applying the coating to the base, of heat treating the coated base, and of machining the composite bearing are disclosed in our copending application, Serial No. 210,370, filed May 27, 1938, now

- adequate.

Patent No. 2,241,789, granted May 13, 1941., of which the present application is a division.

It is ,to be observed that the nature of the bond between the base and layer metals or alloys will vary with the chemical and physical properties of these materials. Some will bond more readily than others, some produce a greater thickness in thebonding than others, and in some cases the amount of bonding is very small. Nevertheless, the superior performance of and new results produced by the novel heat-treated products is direct evidence that the heat treatment is beneficial and desirable. It is also true that the heat-treatment produces a certain amount of sintering and intra-diifusion in the layer metal, when applied by spraying, for example, and that this is of distinct advantage in reducing (but not completely eliminating) the porosity thereof. Similarly, the heat-treatment importance. When the heat-treatment is conducted in an atmosphere of reducing gases, it tends to eliminate oxides by reduction, particularly in the cases of sprayed coatings.

It, is to be noted that the porous nature of sprayed metal coatings is distinctly advantageous with regard to their use as bearing surfaces. This porosity enables them to absorb a considerable amount of lubricating medium and hold the latter in reserve for periods in which, for one reason or another, the lubrication is not For example, the bearing on .which a sprayed coating has been applied may be subjected to a vacuum to remove the air from the pores and then immediately immersed in a liquid lubricant under high pressure to impregnate the bearing with the lubricant.

As those skilled in the art will readily understand, the selection of the exact nature or properties of the layer material must be governed by the type of service desired. For example, if the corrosive medium in which the alloy must work is a sulphuric acid medium, a lead-containing layer alloy would preferably be chosen; if the corrosive medium is sea water, a silver-cadmium layer alloy containing about to 95% of silver with the balance cadmium would preferably be chosen. Particularly satisfactory results have been obtained within the range of about 65 to 95% silver, and a preferred range is about 75% to 85% silver, with the balance substantially cadmium. A similar choice may also-be made with reference to the base metal. For example, if high tensile strength is desired combined with lightness (low specific gravityione or more of the aluminum alloys of the age-hardening type would be selected; if high strength and hardness with corrosion resistance are desired, one of the alloys of the 'aluminum-copper-nickel type previously mentioned would preferably be chosen.

The present invention contemplates the use of a layer alloy which improves the corrosion resistance as well as the anti-galling properties of In corrosionresisting services this latter feature is of great I ing on steel.

the base-alloy,-such as a silver-cadmium coat- For special purposes, a generally considered base metal may also be used as a layer metal in order to impart specially desired properties together with hearing characteristics, such as, for example, the use of bronze on nickel alloys or the use of aluminum alloys on steel.

From. a broad point of view, when resistance to corrosion is involved, the selection of the layer material is based in part upon the position of the materials involved in the well established electromotive series. For best results, not only the chemical properties of the layer material must be considered but also its position in the electromotive series. Its position in the series should, in general, be lower than that of the base material, 1. e., the layer material should be cathodic with respect to the base material. selection on the foregoing basis will serve to decrease the likelihood of corrosion. of the layer material.

For the purpose of securing best results, especially in connection with sea water, we prefer to use a base constituted of nickel base alloys. Typical of such alloys are nickel-copper alloys sold under the trade-mark Monel and nickelchromium-iron alloys sold under the trade-mark Inconel. We may also use iron base alloys, such as the carbon and alloy steels, or copper base alloys, such as brasses, bronzes and nickel silvers, or aluminum base alloys, preferably of the age-hardening type, such as duralumin.

For the layer, we prefer to use silver or cadmium or alloys thereof. We may likewise employ anti-friction materials, such as tin, zinc, aluminum, lead, copper, antimony, carbon (graphite), indium, beryllium, bismuth, gold, palladium, platinum, silicon, rhodium, etc., singly or in combination. Indium is of particular benefit in increasing the corrosion resistance of certain of the cadmium and copper base alloys.

When it is diiiicult or impossible to obtain a diffusion bond between the layer and the base metals, an intermediate layer of a satisfactory bonding element or alloy will first be coated on the base metal prior to application of the selected layer material. In this manner, an anti-friction and anti-galling structure or bearing is produced comprising a base, an intermediate layer, and a bearing layer. Upon subsequent appropriate heat-treatment, the desired bond would be obtained, thus producing a structure or bearing comprising a plurality of irregular layers or laminations bonded to the base. For the purpose of providing specific corrosion-resisting properties to the base metal when the surface coating of bearing metal would be unsatisfactory for this purpose an intermediate metallic coat may be of 'value. While a difiusion bond is highly desirable, particularly if it has good physical properties, it is not absolutely necessary.

The thickness of the applied layer metal may vary within relatively wide limits, but for practical purposes thicknesses from about 0.0005 to about 0.050 inch have iven satisfactory results. In any particular case, the thickness will be governed by the nature of the material used, its ease of application, its ease of bonding by heat-treatment, and the like. We have produced satisfacof both base and layer metals. After heat-treatment, the surface of the work may-be smooth machined or allowed to remain slightly rough as desired. The thickness of the coating in its final form is in the order of magnitude of about 0.001 inch. When manufacturing the parts to be subsequently treated, theyare finished from about 0.0005 inch to about 0.001 inch below the tolerance specified.

The type of finished surface desired is one in which the coating or layer metal has been machined down until minute areas of the base metal starts showing through'the coating. In other words, a hill and valley structure in which the exposed tops of the hills are base metal and the valleys are filled with anti-friction metal. The coating is dressed down until the area of exposed base metal is equal to about 20% of the total bearing surface. The ratio of the exposed base metal to the silver-cadmium coating that remains is therefore about 1:4. It is important that the finished bearing surfaces show a uniformly spotted or leopard skin effect. It is essential that the base metal mountain or hill tops peeping through the valleys filled .wth layer metal be fineof a relatively softer constituent, but the islands in the bearings embodying the present invention are formed of a plurality of relatively hard grains forming a load supporting structure (e. g., of a nickel-copper alloy) surrounded by a matrix or ground mass of soft plastic material (e. g., silvercadmium alloy) Figs. 1 and 2 show desirable types of bearing surface. The light areas represent the layer of anti-friction metal, in this embodiment constituted of Ag-Cd alloy, and the dark areas depict the tops of the hills or projections on the roughened bearing face of the base or foundation stratum constituted of aluminumecopper-nickel alloy.

These figures illustrate the desired spotted or mottled or variegated finished bearing surface.

Fig. 4 is similar to Fig. 3 and illustrates schematically the embodiment of the invention in which an intermediate layer is used to assist in bondingthe outer layer of bearing-metal to thebase or foundation stratum. The intermediate layer; as described hereinbefore and as understood by those skilled in the art, should be capable of forming a diffusion bond between the layer and the base metals, i. e., should be a metal which alloys comparatively easily with the base metal and the bearing metal when exposed in intimate contact therewith at heat treating temperatures. Satisfactory results have been obtained, for example, using tin as the bonding metal between a base of aluminum-copper-nickelalloy and a layer of silver-cadmium bearing metal. Tin has also been used satisfactorily between the same type of base metal and bearing metal layers of silver and phosphor bronze. (See Table I, below.) The application or deposition of a plurality of layers of different metals to the roughened face of the base or foundation stratum produces, prior to the machining or dressing operation, an intermixed or agglomerate body having a plurality of irregular laminations or strata which become bonded to the base during the heat treating step. When the bearing surface is then dressed or machined by any suitable mechanical operations to reduce the bearing to required dimensions and to provide the required smooth surface finish, these irregular strata are cut or cross sectioned at various angles depending upon the angle of slope of the ad- 'jacent projection or hill to the surface. The finished surface thus comprises contiguous areas of different metal constituents of the 'bearing prO- ducing a mottled or variegated bearing surface.

In Table I are summarized the results obtained ina long series of tests on an aluminum-coppernickel alloy or a copper-nickel alloy which was surfaced with different alloys and was treated in accordance with the principles of the present invention to produce a novel product. tests a diameter'rod was rotated in a 2 inch cubic block of the same metal, without lubrication of any kind and under considerable pressures:

Table I Metal for 2 in. g p Layer z on fifai i egin ii t ii Load R.P.M. Time to produce gelling for A 1 lame or lame er rod hydrogen atmosphere) A Pounds Minutes Cu-Ni alloy None 24 0.75 to 1.2.

Do do 1, 000-2, 000 a) Zinc 2,000

Chromium plated 2, 000 19 3.0. Tin 2, 000 19 14.0.

None 1,000-2, 000 20 0.20 to 1.66.

Phosphor bronze "do 2. 000 19 8.75-45.0. 'lin 6 hrs. at 420 F. 2, 000 19 60.0 (surface not gelled but slightly sealed). 'Iin and phosphor bronze... 6 hrs. at 420 F 2, 000 19 60.0 (surface not galled but slightly scaled).

Silver and tin 6hrs. at 420 F 2,000 19 60.0 gsigiace not gallcd and only sli htly sea e Silver and cadmium with 2 hrs. at 600 F. fol- 2,000 20 60.0 (no galling but considerable scaling).

tin as intermediate layer. loggedFby 3 hrs at 7 Silver and cadmium 6 hrs. at 420 F 2, 000 10' 60.0t(su(|1'fa?ctnrt galltcg and alm)nst as'gnod a on 0 es as a egmmn Do Silver and cadmium 10 hrs. at 750 F 2. 000 20 00.0 (no gelling but some scaling).

A designates a copper-nickel alloy. B designates an aluminum-coppcr-nickcl alloy.

Fig. 3 shows a desirable type of bearing surface in cross section. The polycrystalline mountains or hills constituted of base metal are peeping through valleys filled with a coating constituted of the anti-friction metal.

7 ducted on thrust bushings in a traversing gear In these boxin comparison with a standard bronze bushing, under conditions where the aluminum-copper-nickel alloy could not be used without surface treatment. Table II summarizes the results of cordance with the principles of the present invention has been in daily continuous service without any of the difficulties previously encountered.

An example showing the excellent resistance this series of tests: to corrosion of the novel product embodying our Table II Cycles elapsed in test at rate of 85 per Type of base metal Layer metal Thrust load Lubrication min. until first Bonding or diflusion heat treatment indication oi gelling occurred Standard bearing bronze None 1,000 Castor oil... 17, 054 None. Al-Cu-Ni alloy Wiped tin 1,000 do 10, 750 'Do. D WipIeid 50-50 lead-tin 1,000 do 4, 977 Do.

so er. I do 1.000 .--..do 19,283 3 hrs. in molten solder at 1,040 F. do 1,000 None 3,120 Do:

Plated Cd 1,000 Castor oil. 16, 250 8 hrs. at 525 F- Silver solder l, 000 do 15,013 2 hrs. at 1050 F. do 1.000 None 5, 391 Do.

invention will now be given. An aluminum-copper-nickel alloy had a bonded 75 per cent silver 25 per cent cadmium surface and was exposed continuously in a 4 per cent common salt (NaCl) solution for two weeks. At the end of this period no evidences of corrosion were detected.

Although the present invention has been described in connection with preferred embodiments, it is to be understood that various modifications may be made without departing from the spirit and scope of the invention as described herein and as defined in the appended claims.

Table III Type of friction a gg lg g g i g Area tested Pressure loud ag m Lubrication Description Res lt nu r D strokes per min.

1. 0.020 in. (machined fin- 2sq. in 1,250 p. s. i. Sliding Light machine oil. (a) see. under friction No failure. ish). followed by 120 sec.

rest period to dissipate temperature. 1 do .do do d (b) 60 see. under friction D and minute rest p 1 do ...d0 d d do (c) 6 cycles of 15 sec. of D0,

""" friction and sec. of

rest.

2 0001-0002 in. (rough lsq. in 1,000 b D Rolliflg- Light ac ine oil. (a) 142 see. under friction Do,

finish). inclgiflof roller followed by 80 sec. rest.

en 2 do -do do do do (b) 13 min. under friction Do,

followed by 1 hr. rest. 2 do .do 1,000 p. s. i. Sliding" do (c) 12 cycles of 15 sec, or

friction and 45 sec. of'

rest.

3 do -.do 1,000 l sp r R ling- Non (a) 76 min. of friction inch of roller length. 3 do ..do 1,000 11.8.1 11 1 02. d0 (b) 12 cycles of 15 sec. of Do,

""" friction and 45 sec. of

re 3 do .d0 2,0001 S- do (c) 12 cycles of 15 sec. of D I friction and 45 sec. rest.

4 No anti-gelling coating ldo 1,000 ns- Sliding" Light ac ine oil. (r) 0590. of friction Badlygglled, machined. Al-Cu-Ni alloy surlace p. s. i. indicates pounds per square inch.

able pressure, exhibited'tendencies to gall and seize in spite of lubrication. The face of this steel spline shaft was provided with a thin -25 silver-cadmium alloy layer by electrodeposition. The results have been very satisfactory and suc- Thus, small amounts of other elements may be included in the silver-cadmium alloy to favorably influence certain of its properties, e. g., indium to improve corrosion resistance, and copper or nickel up to about 2% to improve the physical properties. In the. foregoing description and the following claims the term bearing face is applied to the surface or surfaces of the base metal which is or are treated in accordance with the cessful and the steel spline shaft treated in acl5 principles of the present invention to form a.

' the bearing.

We claim:

1. A composite metallic anti-friction and antigalling bearing comprising a body of coppernickel alloy and a layer of silver-cadmium alloy bonded together at their interface, the bearing face of the body having a plurality of small approximately equally spaced hills, separated by shallow valleys, over substantially its entire surface, the bearing surface comprising tops of said hills surrounded by a matrix of the cadmiumsilver alloy.

2. A composite metallic anti-friction and antigalling bearing comprising a body of base metal of desired strength but deficient in anti-friction and anti-galling properties and a layer of cadmium-silver alloy containing about 10 to 95% silver and the balance substantially cadmium, the face of said body in contact with said layer being provided with a plurality of small metal hills extending through said layer to provide a bearing surface comprising areas of said metal hills surrounded by a matrix of the cadmium-silver alloy.

3. A composite metallic bearing comprising a body of base metal having a bearing face, and a layer of silver alloy containing about to 35% cadmium anchored to said face by projections from said body extending through said layer.

4. A corrosion resistant bearing comprising a body of nickel alloy possessing strength and corrosion resistance, a plurality of projections on one face of said body, and an adherent layer of bearing metal softer than said nickel alloy body bonded to said face, the bearing surface comprising tops of said projections surrounded by said bearing metal.

5. A hearing adapted for use in contact with sea water, brines and the like comprising a body of nickel-copper alloy possessing strength and corrosion resistance and an adherent layer of silver-cadmium alloy intimately bonded thereto, said body of nickel-copper alloy having a plurality of projections of small cross sectional size extending through the layer of silver-cadmium alloy and forming a minor part of the bearing surface.

6. A composite metallic anti-friction and antigalling bearing having a bearing surface comprising a plurality of separate irregular macroscopic islands of an alloy comprised largely of nickel and copper constituting a load supporting struc-. ture surrounded by a matrix of bearing metal,

said islands of nickel-copper alloy forming a minor portion of said bearing surface and said matrix of bearing metal forming a major portion of said bearing surface.

7. A composite metallic anti-friction and antigalling bearing having a bearing surface com- 5 prising a plurality of separate irregular macroscopic islands of a copper-containing alloy constituting a load supporting structure surrounded "by a matrix of bearing metal containing lead,

said islands of copper-containing alloy forming a minor portion of said bearing surface and said matrix of lead-containing bearing metal forming a major portion of said bearing surface.

8. A composite metallic anti-friction and antigaliing bearing having a bearing surface comprising a plurality of small separate irregular islands of an alloy comprised largely of nickel and copper constituting a load supporting structure surrounded bya matrix of an alloy comprised largely of lead andtin, said islands of nickel-copper alloy forming a minor portion of said bearing surface and said matrix of lead-tin alloy'forming a major portion of said bearing surface.

9. A bearing having a composite surface com- 5 prised in major part of a silver-cadmium alloy containing silver as the major constituent and the balance of said surface being small, polycrystalline islands of material harder than the surrounding silver-cadmium alloy.

10. A hearing having a composite surface comprised in part of bearing metal and the balance of said surface being small, polycrystalline islands of nickel alloy harder than the surrounding hear.- ing metal.

body of base metal having a bearing face and a layer of silver alloy containing up to about 2% of at least one metal of the group consisting of nickel and copper anchored to said face by projections from said body extending through said layer.

12. A composite metallic bearing comprising a body of base metal having a bearing face and a layer of an alloy including silver in predominant amounts and the balance substantially cadmium, anchored to said face by projections from said body extending through said layer.

13. A composite metallic bearing comprising body of base metal having a bearing face and a layer of an alloy comprising about 10% to 95% silver. small amounts of indium eifectiveto increase the corrosion-resistance of the alloy, and the balance substantially cadmium, anchored to said face by projections from said body extending through said layer.

PAUL ETIENNE QUENEAU. WILLIAM ALVIN MUDGE.

11. A composite metallic bearing comprising a v

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