Anti-seize Lubricating Compound

Bergeron, deceased March 28, 1

Patent Grant 3652414

U.S. patent number 3,652,414 [Application Number 04/789,425] was granted by the patent office on 1972-03-28 for anti-seize lubricating compound. Invention is credited to Frank E. Bergeron, deceased.


United States Patent 3,652,414
Bergeron, deceased March 28, 1972

ANTI-SEIZE LUBRICATING COMPOUND

Abstract

A lubricating and sealing compound for sealing pipe threads and the like comprising: (1) 4 percent to 92.5 percent by weight of a base lubricating agent and, preferably, of a base grease produced using a soap from the group of aluminum, barium, calcium complex, lithium and sodium soaps; (2) 2 to 20 by weight of a fish oil-based lead soap; (3) 0.5 to 10 percent by weight of a sulfur modified sperm oil such as sulfurized or sulfonated sperm oil; and (4) 5 to 90 percent by weight of solids. The solids comprise either copper alone or, preferably, copper in combination with; (5) 5 to 30 percent by weight of this compound of powdered lead; and (6) 5 to 30 percent weight of amorphous graphite.


Inventors: Bergeron, deceased; Frank E. (La Canada, CA)
Family ID: 25147608
Appl. No.: 04/789,425
Filed: January 6, 1969

Current U.S. Class: 508/119; 508/123
Current CPC Class: C10M 5/00 (20130101); C10M 7/00 (20130101); C10M 2201/042 (20130101); C10M 2207/282 (20130101); C10M 2201/041 (20130101); C10M 2207/125 (20130101); C10N 2050/10 (20130101); C10N 2010/08 (20130101); C10M 2201/103 (20130101); C10M 2219/024 (20130101); C10M 2201/064 (20130101); C10M 2203/108 (20130101); C10M 2207/34 (20130101); C10M 2207/129 (20130101); C10N 2010/04 (20130101); C10N 2010/06 (20130101); C10M 2219/044 (20130101); C10N 2010/02 (20130101)
Current International Class: C10m 005/22 ()
Field of Search: ;252/19,35,26

References Cited [Referenced By]

U.S. Patent Documents
2065248 December 1936 Smith
2295189 September 1942 Swinson
2543741 February 1951 Zweifel
2790770 April 1957 Fainman et al.
2818386 December 1957 Francis et al.
2888402 May 1959 Nelson
3003962 October 1961 Jordan et al.
3396108 August 1968 Caruso
Primary Examiner: Wyman; Daniel E.
Assistant Examiner: Vaughn; I.

Claims



It is claimed:

1. An anti-sieze lubricating compound comprising an oil thickened to a grease consistency with a metallic stearate soap selected from the group consisting of aluminum stearate soap, barium stearate soap, calcium complex stearate soap, lithium stearate soap, and sodium stearate soap; and containing synergistic anti-sieze proportions of:

a. a fish oil lead soap,

b. sulfurized sperm oil,

c. finely divided copper,

d. powdered lead, and

e. amorphous graphite.

2. The lubricating compound of claim 1 wherein the fish oil in the fish oil lead soap is selected from the group consisting of tuna oil, herring oil, menhaden oil, anchovy oil, mackeral oil and sardine oil.

3. The lubricating compound of claim 2 wherein the oil which is thickened to a grease consistency is mineral oil.

4. The lubricating compound of claim 3 containing from about 1 percent to about 15 percent by weight of the fish oil lead soap.

5. The lubricating compound of claim 4 containing from about 0.5 percent to about 7.5 percent by weight of the sulfurized sperm oil.

6. The lubricating compound of claim 5 containing at least 5 percent by weight of copper and between about 5 percent and about 30 percent by weight of each of the powdered lead and the amorphous graphite.

7. An anti-sieze lubricating compound comprising an oil thickened to a grease consistency with an aluminum stearate soap and containing synergistic anti-sieze proportions of:

a. a fish oil lead soap,

b. sulfurized sperm oil,

c. finely divided copper,

d. powdered lead, and

e. amorphous graphite.

8. The lubricating compound of claim 7 wherein the fish oil in the fish oil lead soap is selected from the group consisting of tuna oil, herring oil, menhaden oil, anchovy oil, mackeral oil, and sardine oil.

9. The lubricating compound of claim 8 wherein the oil which is thickened to a grease consistency is mineral oil.

10. The lubricating compound of claim 9 containing from about 1 percent to about 15 percent by weight of the fish oil lead soap.

11. The lubricating compound of claim 10 containing from about 0.5 percent to about 7.5 percent by weight of the sulfurized sperm oil.

12. The lubricating compound of claim 11 containing at least 5 percent by weight of copper and between about 5 percent and about 30 percent by weight of each of the powdered lead and the amorphous graphite.
Description



BACKGROUND OF THE INVENTION

This invention relates to anti-seize lubricants and, more particularly, to lubricating and sealing compounds for pipe threads, bolting and the like.

In applications such as in oil well drilling, piping must be capable of being threadedly coupled and uncoupled even though subjected to high temperatures, for example, 450.degree. F. and above, and to high pressures, for example up to 6,000 p.s.i. and higher. Additionally, threaded pipe joints must be capable of preventing leakage of fluids through the helical thread passages of pipe joints even though the fluids may be under relatively high pressure and even though the pipe joints may be subjected to constant vibration. Bare metal contact between threaded-together pipes, under the foregoing conditions, results in the pipes "freezing" and/or welding together. Additionally, thread tolerances are such that substantial leakage can occur where only metal-to-metal contact exists between threaded-together pipes.

To overcome the foregoing problems, various lubricants and/or sealing compounds have been developed. Such compounds, when painted onto interlocking threads, produce a marked improvement over metal-to-metal contact in preventing both welding of the metal parts and leakage of fluids through the threaded joint. One such lubricating and sealing compound is described in U.S. Pat. No. 2,543,741, issued Feb. 27, 1951, to H. C. Zweifel. The Zweifel U.S. Pat. No. 2,543,741 describes an improved sealing and lubricating compound for pipe threads and the like containing a combination of copper, powdered lead and amorphous graphite in a petroleum vehicle comprising mineral oil and metallic soaps such as aluminum, lithium, sodium and calcium soaps and clay base thickeners. The improved characteristics of this compound rest primarily on the superior lubricating characteristics of the flaked copper and upon the superior sealing characteristics of the combination of amorphous graphite and powdered lead in combination with the copper. A further desirable characteristic of the Zweifel compound is that it is capable of laying down a thin film of copper at locations on the threaded metal surfaces where the surface has been worn and roughened due to extreme pressure.

The Zweifel composition prolongs the useful life of the threaded joints in which it is employed because it tends to heal the scars and roughened areas resulting from excessive wear and makeup torques just below that pressure required to cause the joint to "freeze or seize" during makeup or breakout. However, roughened surfaces and relatively high pressures are required to lay down the aforementioned copper film. Thus, the copper film primarily acts as a healing agent rather than a score prevention agent. Although the Zweifel U.S. Pat. No. 2,543,741 compound represents an improvement in its ability to withstand breakdown as measured by the standard Timken test method, as compared to the base grease from which it was prepared, today's deep drilling techniques, as employed in oil field drilling, demand an even greater ability to withstand breakdown.

As previously noted, the ability of a lubricant to withstand extreme pressures without breaking down is a highly desirable characteristic of such compounds. However, it has been generally overlooked that, as the load bearing capabilities of the lubricating agent increase, the area of the scar produced on a test block subjected to the aforementioned Timken test increases markedly. Although a larger scar area would generally indicate a longer life for the metal because of a lower pressure per unit area of scar, the larger scar ares itself has an offsetting detrimental effect on the useful life of the metal part. That is, the detrimental increase in scar area more than offsets the beneficial increase in the load bearing capacity provided by the lubricant. Therefore, it is of paramount importance to reduce the scar area. Presently available lubricating compounds, while notably increasing the load bearing capacity of threaded joints, do so at the expense of the useful life of the threaded parts due to the aforementioned increase in scar area.

SUMMARY OF THE INVENTION

The compound of this invention is an anti-seize compound comprising a base lubricating agent in amount between about 4 percent and about 92.5 percent by weight, a fish oil-based lead soap in amount between about 2 percent and about 20 percent by weight, a sulfur modified sperm oil in amount between about 0.5 percent and about 10 percent by weight, solids in amount between about 5 percent and about 90 percent by weight, the solids comprising copper alone or, preferably, powdered lead in amount between about 5 percent and about 30 percent by weight of the compound, and amorphous graphite in amount between about 5 percent and about 30 percent by weight.

More specifically, the base lubricating grease is presently preferably formulated from the combination of a mineral oil and a soap selected from the group of aluminum soap, calcium complex soap, barium soap, lithium soap, and sodium soap. The fish oil-based lead soap is formulated from the combination of lead and a fish oil such as tuna oil, herring oil, sardine oil and menhaden oil, in a suitable petroleum base oil. The sulfur modified sperm oil may be sulfonated sperm oil, but is preferably sulfurized sperm oil.

The compound of this invention exhibits the aforedescribed desirable characteristics of the lubricating compound described in the Zweifel U.S. Pat. No. 2,543,741. That is, the compound of this invention has excellent lubricating and sealing characteristics due to the presence in this compound of the copper, graphite and powdered lead solids. Furthermore, the compound of this invention exhibits a substantially increased load bearing capacity and wear reducing ability as compared with the compound described in the Zweifel U.S. Pat. No. 2,543,741.

The addition of the various aforedescribed components to the base grease to produce the compound of this invention produces a lubricating compound which has a substantially higher resistance to load than does the base grease alone. Unexpectedly, and contrary to the performance of other similar lubricating compounds, the compound of this invention produces wear scar areas on test blocks (when subjected to the Timken test) which are smaller than the wear scars produced by the base grease alone at lower loading. Thus, the useful life of metal surfaces protected by the compound of this invention is improved both by the increased load carrying ability of this compound and by its ability to decrease the size of scar marks produced in the metal surface.

In contrast to the Zweifel U.S. Pat. No. 2,543,741 compound, the compound of this invention acts as a scar prevention agent as contrasted with a scar healing agent in that the copper contained in the compound is laid down on a metal surface protected by this compound in thin film form at relatively low pressures and even on smooth surfaces. That is, even before the surface has been roughened, as required for copper deposition from the Zweifel U.S. Pat. No. 2,543,741 compound, the copper is laid down as a thin film to begin protecting the metal surface from additional loading. The early deposition of copper by the compound of this invention extends the useful life of the metal part which it is intended to protect because the wear resistance of the copper takes effect before the wear resistance of the lead soap and sulfur modified sperm oil, which decreases with increasing loading, is lost, thereby providing an overlapping of the wear resistance characteristics of the lead soap and copper and thus increasing the wear resistance characteristics of the total compound.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In general, the lubricating compound of the invention is an extreme pressure, anti-seize compound which comprises, in combination, specific amounts of a base lubricating agent, a fish oil-based lead soap, a sulfur modified sperm oil, and solids comprising either copper alone or, preferably, the combination of powdered lead, copper, and amorphous graphite. This compound has a grease consistency and is formulated using amounts of the above-identified components so that the solids are dispersed therein.

Preferably, the base lubricating agent is a grease derived from the combination of a mineral oil and a soap selected from the group of aluminum, barium, lithium, calcium complex, and sodium soaps. The fish oil-based lead soap is a soap derived from the combination of lead and a fish oil in a suitable petroleum oil base and the sulfur modified sperm oil may be sulfurized or sulfonated sperm oil.

This compound exhibits improved load bearing and wear reducing characteristics. As to the latter characteristic, not only are scars produced on the underlying, protected surfaces reduced in area, but copper is deposited on the underlying surface at substantially lower loads than heretofore achieved. The reasons for these improved results and, particularly, for the early, i.e., low load, deposition of copper are not fully understood. However, it is presently believed that the early deposition of copper is due to an interaction between the fish oil-based lead soap and sulfurized or sulfonated sperm oil to form a compound which forms a film on the underlying surface to which the copper adheres.

All concentrations given herein are percent by weight and are percent by weight of the total compound of this invention unless otherwise indicated.

Turning now to the particular components of the compound of this invention, the base lubricating agent will first be described. The base lubricating agent may be a viscous oil alone, for example, a bright stock or it may be a semi-solid grease comprising an oil and a gelling agent or soap. The oil in the grease may be any suitable oil such as a polymerized hydrocarbon, e.g., polybutyne or polyisobutene, a synthetic oil, e.g., dioctyladipate or, preferably, a mineral oil. Combinations of these oils may also be used. The preferred mineral oil is preferably a neutral type hydrocarbon oil having a Saybolt Universal viscosity at 100.degree. F. in the range between about 100 and about 500 seconds (S.U.S.). Useful mineral oils well-known in the grease-making art include, for example: pale oil, red oil, process oil, neutral oil, floor oil, brown neutral oil, neutral distillate, treated neutral oil, and blends of these mineral oils from any petroleum source. These oils may contain bright stocks or other hydrocarbon materials capable of modifying the physical characteristics of the neutral oils.

Preferably, the gelling agent is a metallic soap. However, it may also be an inorganic thickening agent such as lampblack or processed clay. The metallic soap may not be normal calcium soap or lead soap, but it may be aluminum, calcium complex, lithium, barium, or sodium soap. A particularly useful metallic soap is aluminum stearate soap. As used herein, the term "soap" is intended to include compounds formed from the combination of metal elements or inorganic elements with animal or vegetable fats, fatty acids or fatty acid derivatives as well as certain petroleum derivatives such as oxidized petroleum.

The presently preferred combination of a mineral oil and a soap are employed in a ratio of mineral oil to soap between about 10:1 and about 19:1 by weight.

The petroleum of the base grease in the total composition is at least about 4 percent, and is sufficient to make 100 percent by weight of the final compound. The upper limit will be 92.5 percent or 82.5 percent depending upon whether the solids are copper alone or copper, amorphous graphite and powdered lead, respectively. Below this lower concentration, the composition is too viscous at applicable temperatures to be properly applied when used for the purposes intended. If less than this amount is used in the composition and low viscosity dilluents are used to compensate for the absence of the vehicle, i.e., the base grease, the composition may, upon standing, no longer be homogeneous. Above this upper concentration, one or more of the components will be present in a ratio to the other components that will result in the compound being partially or completely ineffective in its intended applications.

The fish oil-based lead soap, which is an extreme pressure agent, comprises: (a) a petroleum or mineral oil base derived from the combination of a bright stock having a viscosity between about 110 S.U.S. (Saybolt Universal Seconds) and about 250 S.U.S. at 210.degree. F. and a neutral oil having a viscosity between about 100 S.U.S and about 500 S.U.S. at 100.degree. F.; (b) a fish oil including herring oil, menhaden oil, sardine oil, mackerel oil, anchovy oil and, preferably, tuna oil; and (c) lead preferably derived from litharge (PbO).

An example of an effective fish oil-based lead soap has the following composition:

Mid Continent Bright Stock (150 S.U.S. at 210.degree. F.) 37.0 lb. Tuna oil 107.5 lb. 30-P oil (310 S.U.S. at 100.degree. F.) 147.0 lb. Litharge 86.0 lb.

The weight fractions of the components present in the fish oil-based lead soap are selected so that the tuna oil is miscible with the other oils and so that the resulting lead soap has a semi-solid or semi-plastic consistency. The amount of fish oil varies within a relatively limited range. For example, in the above-identified, tuna oil-based lead soap, the tuna oil may vary in amount between about 110 lb. and about 105 lb. Above about 110 lb. the resulting soap is so hard as to be practically unworkable and has to be heated before attempting to mix it with the base lubricating agent. Below about 105 lb., the resulting soap is too thin and tends to break down the structure of the base grease.

The fish oil-based lead soap is made by first mixing the litharge and the bright stock together to form a paste. Heating of this paste is commenced and the tuna oil is added with stirring. Heating is continued until the temperature of the mix rises above about 300.degree. F. and, preferably, to a temperature between about 300 F. and about 320.degree. F. When this elevated mix temperature has been reached, the low viscosity neutral oil is slowly added to thin the mix. The temperature of the mix is maintained above about 300.degree. F. during the entire addition of the neutral oil. If the mix temperature falls below about 300.degree. F., the reaction time is extended to the extent that the time becomes impractical and the desired reaction may not be completed. Heating of the mix is continued until substantially all of the litharge has reacted.

The fish oil-based lead soap is present in the compound of this invention in an amount between about 2 percent and about 20 percent. Below about 2 percent, the ability of the lead soap to perform the functions herein described is lost because of a dilution phenomenon characteristic of such compounds in a lubricating grease structure as opposed to their effectiveness in a non-thickened lubricating oil. This minimum ratio is established to assure the extreme pressure properties resulting in the synergistic phenomonon involving the essential presence of sulfurized or sulfonated sperm oil to accomplish the phenomenon of copper deposition and lower range, extreme pressure properties described herein. Above about 20 percent, the effectiveness of the lead soap diminishes at a rate to make economically unfeasible the use of an increased ratio of the lead soap to the other components of the composition.

The sulfur modified sperm oil may be either sulfonated or sulfurized sperm oil, but is preferably the latter which is a sperm oil having a sulfur content of about 8 to 12 percent by weight. The sperm oil is present in amounts between, about 0.5 percent to about 10 percent by weight. Below about 0.5 percent, the sperm oil is too diluted by the base grease to have any appreciable effect on the weld-prevention and wear-reduction properties of the compound of this invention. Above about 10 percent, the effectiveness of the sperm oil diminishes too rapidly to make the use of amounts of sperm oil above 10 percent economically feasible.

The copper or the combination of copper, powdered lead and amorphous graphite comprise what is hereafter designated as the "solids" constituents of the hereindescribed compound. The copper is fully described in the Zweifel U.S. Pat. No. 2,543,741 and that description is incorporated herein by reference. The term copper as used herein and in the claims denotes both elemental copper and copper alloy which, in turn, is used herein to designate an alloy having copper as the major constituent. The copper is present in the form of fine flakes or scales and preferably is in the form of particles ranging in size from about 1 micron to at least about one-half times larger, in their largest dimension, than the maximum combined tolerances of both the mating male and female threads. Generally, the copper particle or flake should not exceed, in its greatest dimension, about 76 microns. Ordinarily, the thickness of the copper particles or flakes will fall within the range of about 3.9 .times. 10.sup..sup.-5 to about 19.5 .times. 10.sup..sup.-5 inches and will generally be of substantially uniform thickness.

The combination of powdered lead and amorphous graphite acts as a damming or sealing agent. This combination effectively seals pipe threads at temperatures ranging from -87.degree. F. up to 450.degree. F. and above, and at pressures up to 6,000 p.s.i. and higher. The consistency of the amorphous graphite and powdered lead is such that they can be easily removed by normal cleaning procedures from the threads.

The total combined solids content, that is, the total of the copper, powdered lead and amorphous graphite, is at least about 15 percent by weight of the total composition, with each of these components present in amounts of at least 5 percent, and may range as high as about 90 percent of the total composition. If copper alone is employed, the lower limit is about 5 percent by weight. Below the lower limit of about 15 percent for the combined solids or about 5 percent for copper alone, the dilluent effect of the base grease and/or other components prevents the presence of sufficient flake copper at points of contact between mating surfaces, for example, threaded members, to adequately prevent excessive wear and/or seizure, welding or galling as the case may be. A lower concentration can result in leakage of threaded joints as described in the Zweifel U.S. Pat. No. 2,543,741. Above the upper limit of about 90 percent of total solids, application of this compound becomes impractical because of its thickness.

The amorphous graphite and powdered lead are present in a ratio of lead to graphite varying within the range of 1:3 to 3:1. Satisfactory results have been produced employing equal amounts of copper, graphite and lead, for example, about 10 percent by weight of the total compound, to give a total solids content of about 30 percent. The maximum amount of each of the lead and graphite is preferably about 30 percent.

The anti-seize, lubricating compound of this invention may be made by combining the components in various ways. For example, it has been found convenient to add the base grease to a conventional grease kettle and, thereafter, to add each of the other components to the base grease with stirring. Generally, no heating is required to completely mix the various components.

To illustrate the unexpected advantages resulting from use of the compound of this invention, various greases having the composition as shown in Table I were made up. --------------------------------------------------------------------------- TABLE I

grease Designation Composition __________________________________________________________________________ Base grease 92.5 % mineral oil (310 SUS at 100.degree. F.) + 7.25 % aluminum stearate soap. Grease A 70% Base grease + 10% copper + 10% lead + 10% graphite. Grease B 85% Base grease + 10% tuna oil-based lead soap (21.5% lead) + 5% sulfurized sperm oil. Grease C 55% Base grease + 10% copper + 10% lead + 10% graphite + 10% tuna oil-based lead soap (21.5% lead) + 5% sulfurized sperm oil. Grease D 90% Base grease + 10% commercial extreme pressure additive (Parapoid 10C) __________________________________________________________________________

grease A represents a lubricating compound made according to the Zweifel U.S. Pat. No. 2,543,741 and Grease B represents an improved lubricating compound made according to the method described in a U.S. patent application of the instant inventor, assigned to the instant assignee and filed herewith (hereafter "said copending application"). Grease C represents a compound of this invention and Grease D represents a presently available extreme pressure lubricant containing extreme pressure agents other than those employed in the present invention.

Each of the compositions of Table I was subjected to a test designed to show the breakdown load of each grease, i.e., the load at which each grease was no longer able to protect the underlying metal surface. The test equipment was a standard Timken lubricant tester for testing extreme pressure lubricants in which a metal ring or test cup is made to revolve and rub against a test block or coupon which is held stationary. A reservoir of special design was provided which continuously flowed lubricant onto the outer surface of the rotating ring so that lubricant was carried into lubricating position between the outer surface of the rotating ring and the contacting surface of the test block or coupon (the underlying surface). The ring was caused to rotate at about 800 r.p.m. and, simultaneously therewith, a load was applied downwardly to the lever arm carrying the test block in a manner to increase the pressure of the test block against the rotating cup or ring. The upward loading of the test block was increased with each test, which ran for about 10 minutes, until the load at which the lubricant passes and fails was determined.

At the end of each 10 minute test, the scar produced on the test block by the revolving ring was examined. A test block scar with straight line sides and no metal pickup indicated that the lubricant was properly protecting the metal surface of the block, whereas a test block scar with metal pickup causing the boundary lines of the scar pattern to be irregular indicated that the lubricant was not capable of protecting the metal surface of the test block at that test load. The loads at which the lubricant protected the metal surfaces (although not necessarily completely) were designated as "pass" loads and the loads at which the lubricant broke down and was completely unable to protect the underlying metal surface were designated as "fail" loads. In addition to a determination of the pass and fail loads, the area of the scar produced on the test block at the pass load, was determined. The results of the foregoing tests are set out in Table 2 below. --------------------------------------------------------------------------- TABLE 2

scar Grease Lever Load Area Pass Load Scar Area Designation Pass Fail in..sup.2 % Change % Change __________________________________________________________________________ Base grease 15 20 0.0235 Base Base Grease A 35 40 0.0260 +133 +11 Grease B 45 50 0.0355 +200 +51 Grease C 45 50 0.0225 +200 -4.2 Grease D 25 30 0.0150 +67 -36 __________________________________________________________________________

as can be seen from Table 2, each of the compounds showed a load increase over the base grease (15 lb. pass). The grease employing the presently available commercial extreme pressure additive (Grease D) produced the lowest load increase (25 lb. pass) whereas the two compounds (Grease B of said copending application and Grease C of this invention) containing the combination of fish oil-based lead soap and sulfurized sperm oil produced the largest increase in pass load (45 lb. pass). The base grease plus solids (Grease A) produced a moderate increase in lever load (35 lb. pass). From the foregoing, it is apparent that the compound of this invention has a substantially greater load resistance than does either the compound with a presently available commercial additive (Grease D) or a compound containing only the base grease and the same amount of copper, lead and graphite (Grease A). The latter comparison indicates that the substantial increase in load resistance derives from the combined fish oil-based lead soap and sulfurized sperm oil and that this increase is apparently not affected by the presence of the solids.

Other advantageous characteristics of the compound of this invention were also noted in connection with examination of the wear scars produced by the foregoing test. First, it was observed that copper was deposited from the composition of this invention on the smooth unscored surface of the wear scar produced at 30 lbs. loading, i.e., at 15 lb. less than the pass load. Although the deposition of a protective layer of copper was described in the Zweifel U.S. Pat. No. 2,543,741 such deposition of copper was always previously associated with scoring or roughening of the wear surface. That is, deposition of copper was heretofore possible only on surfaces which had been scored or roughened by the load applied to them. This was borne out by the foregoing tests summarized in Table 2. At both 20 lb. and 25 lb. lever loads with Grease A, no scoring or roughening of the underlying metal surface was observed and no copper deposition was observed. However, copper deposition was observed with this Grease (A) at 35 lb. load together with a scored underlying metal surface.

Thus, the function of copper in the Zeifel U.S. Pat. No. 2,543,741 composition was as a sealant in that the surface was required to be roughened before the copper would deposit to protect the surface from further injury. In contrast, the deposition of copper from the composition of this invention does not require that the surface be initially roughened or scored. Therefore, such deposition of copper begins to protect the metal surface from scoring at pressure less than those at which scoring occurs.

The early, i.e., at relatively low loads, deposition of copper means that the advantages of the protective layer of copper on the metal surface is obtained at lower load conditions so that the protection effected by the copper is obtained before the protection from the lead soap component of the grease is lost. This overlapping of protection derived from the lead soap and the copper film results in continuous protection over a wider range of loads thereby resulting in substantially longer protection of the metal surface from scoring.

Comparison of the scar areas indicates that a synergistic result is produced by the components of the compound of this invention, i.e., apparently by the combination of the fish oil-based lead soap, sulfurized sperm oil and solids (copper, graphite, lead). In which combination these components act to produce the synergistic effect is not presently known. However, the synergistic effect itself is readily observable from the test data of FIG. 2.

Grease A (containing the solids, but no lead soap or sperm oil) exhibits a wear scar area increase over the base grease of 11 percent at its higher pass load of 35 lb. Thus, a substantial increase (+133 percent) in pass load over the base grease is accompanied by a small increase (+11 percent) in scar area over the base grease. Grease B (containing no solids, but containing both fish oil-based lead soap and sulfurized sperm oil) exhibits a 200 percent increase in pass load over the base grease, but is accompanied by a 51 percent increase in scar area over the base grease.

From this data, it would be expected that a grease containing the solids and fish oil-based lead soap and sulfurized sperm oil would exhibit a wear scar area increase and that this increase would probably be between the increases for Grease A and Grease B. However, this expected result does not occur as shown by the data obtained from the tests on Grease C. Instead, the load increase is equal to the higher load increase (+200 percent) of Grease B and this is accompanied by a decrease (-4 percent) in scar area over the base grease. Thus, at loads triple those to which the base grease can be safely subjected, Grease C actually permits less wear than does the base grease at its lower pass load. By comparison, although Grease A and B are capable of withstanding higher loads than the base grease, this capability is accompanied by a wear scar increase.

Grease D (employing a commercial extreme pressure additive) also exhibited a decrease in wear scar area as compared to the base grease. However, this scar area decrease was associated with only a 67 percent increase in load resistance. At 35 lb. load (fail), this grease permitted substantial scoring of the underlying surface and at 45 lb. load (fail) it permitted total scoring of the underlying surface. Because of its lower load capability, it could not be successfully used in the extreme pressure applications in which Grease C of this invention could be successfully employed.

Should scoring of the wear surface take place when using the composition of this invention, copper will be deposited in the scored area to thereby effect a healing of the scored area. Thus, in addition to the increased protection derived from the early deposition of copper from the herein-described composition on smooth wear surfaces, the healing advantages of the Zweifel U.S. Pat. No. 2,543,741 composition are retained.

When a lubricant is subjected to a load at or near its failure load, it is common for a weld ridge resulting from metal build-up to be produced at points along the edge of the wear area. In each such instance, a distressed area is produced in the wear scar adjacent to the weld ridge. This distress area serves to further weaken the metal, thereby further decreasing its useful life. This phenonomen was observed in connection with the tests run on the Zweifel U.S. Pat. No. 2,543,741 composition at 35 lbs. load. By comparison, although weld ridges were produced in the test blocks at 40 lb. and 45 lb. load when using the hereindescribed composition, no evidence of distress in the wear scar area adjacent the weld ridge was observed. Therefore, the useful life of the metal is extended due to the elimination of the stress area adjacent to a weld ridge when using the sealing and lubricating composition of this invention.

From these tests, it will be apparent that the compound of this invention produces the advantages provided by the Zweifel U.S. Pat. No. 2,543,741 composition and, furthermore, that it produces the additional advantages of early copper deposition on smooth surfaces and decreased wear scar area even at high pass loads.

* * * * *


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