US3124531A

US3124531A - Metal working lubricant

Info

Publication number: US3124531A
Authority: US
Publication date: 1964-03-10
Anticipated expiration: 1981-03-10

Description

United States Patent 3,124,531 METAL WORKING LUBRICANT Joshua C. Whetzel, Jr., Fox Chapel, and Sayre Rodman, Oakmont, Pa., assignors to Far-Best Corporation, Los Angeles, Calif, a corporation of California g No Drawing. 'Filed Oct. 28, 1959, Ser. No. 849,147

- 4 Claims. (Cl. 25252) This invention relates to improved lubricants for use in Working metal as by rolling, drawing or forging aluminum or other metal and is described herein particularly as applied to the rolling of aluminum sheets and foil.

While rolling aluminum and aluminum alloys to produce sheet or foil, lubricants are used to decrease friction between the metal and rolls of the rolling mill and to promote good surface finish. These lubricants also serve as heat transfer fluids to remove heat generated in the rolls and metal during rolling. In addition to the above uses, lubricants should be compounded so as to minimize stain on the surface of the metal during anneal cycles or in storage. These lubricants should be non-toxic to mill personnel in use and also non-toxic to subsequent users of the metal if residual films of lubricant remain on the metal surface. Further, these lubricants should not possess objectionable odors and they should satisfy the usual criteria of availability and economy.

Lubricants used for rolling of aluminum are almost always mixtures of polar or oiliness additives with light mineral or hydrocarbon oils or distillates.

I The additives employed for aluminum rolling are generally fats, such as palm oil or lanolin, or other esters of fatty acids,, such as butyl stearate. The purpose of these additives is to provide the light mineral oil or mineral distillate with more oiliness or boundary lubricating ability than it would otherwise possess. Generally, these fatty esters, being closely related chemically, all work in about the same way. They show characteristic relationships between concentration in a lubricant and resultant effects.

The effect of additives in rolling lubricants is to improve the lubricating ability of the oil, thus decreasing friction in the roll bite between rolls and metal. By resultant effects, a decrease in friction allows greater and more eflicient reduction in thickness of the metal being rolled. These additives also, through their chemical or polar action, serve to decrease the tendency of the metal to weld to or pick up on the surface of the rolls during rolling.

For most rolling jobs, the concentration of additive in the light petroleum oil or distillate will range from 1 to about At intermediate stages in the manufacture of aluminum sheet or foil, the rolled strip metal must be annealed or heat treated to soften its structure. In a majority of cases, probably, the final manufacturing step before shipment will be an annealing treatment. The typical heat treating cycles demand that the metal be heated for a period of time at temperatures ranging from about 650 F. to about 900 F., usually in an inert atmosphere. Because of industrypractices, the rolling lubricant is allowed to remain ice on the metal surface during this operation. Thus, careful attention must be given to the tendencies of both additive and base oil to form residues as a result of such heating. These residues which commonly occur to a minor extent are called stains" and appear on the metal surface as a discoloration, marring the luster and value of the product.

Of prime importance in considering the staining tendencies of a potential additive or base oil is the boiling range of these materials and their heat degradation (cracking or polymerization) behavior in atmospheres of the type found in annealing furnaces.

The vehicle used for rolling, light mineral or petroleumderived light oils and distillates, will vary in viscosity in usual work from about 30 to about 60 Saybolt seconds, universal, at F. The choice of viscosity for a particular rolling job will vary with the particular requirements. Reduction per pass, assuming equivalent rolling loads and equivalent additive concentration, normally increases with increasing oil viscosity. Capacity of a lubricant to remove heat from the rolls and metal will vary inversely with increasing viscosity. Also, finish or luster of the rolled metal is somewhat dependent upon the viscosity of the lubricant used in rolling, so long as other factors, unrelated to lubrication, remain equal. And, in addition, the amount or degree of stain remaining on the rolled product after annealing will vary directly with oil viscosity and boiling range.

Therefore, to provide the desired properties and necessary requirements in particular cases of rolling, we find relatively well defined lubricants in general use. For heavier so-called sheet gauges or on breakdown mills rolling sheet destined for lighter gauges, light mineral oils with viscosities of about 38 to 45 Saybolt seconds, universal, at 100 F., are used compounded with about 1 to 5% of fatty oils or fatty acid esters. In the manufacture of light gauge aluminum sheet and foil, close control of roll temperature is necessary to control roll shape and thus good heat transfer fluids are needed. This requirement dictates the use of lighter distillates, such as kerosene, in the viscosity range of 30 to 35 Saybolt seconds, universal, at 100 F. Also, in such application, less reduction is often taken and, at the same time, luster, finish and stain requirements are very strict. All of the requirements dictate the use of light distillates, such as kerosene, usually compounded with 5% or less of fatty oils or fatty acid esters.

An object of our invention is to provide a more useful additive than has been known previously for use in light mineral oils and distillates to form a lubricant for metal working, particularly to lubricate the rolling of aluminum sheet and foil.

We havefound that the combination of fatty alcohols of the general formula R-OH, where. R is a straight paraifinic chain of from 10 to 20 carbon atoms, either saturated or partially unsaturated, and polypropylene glycols of the general formula HO-CH CHCH O--CH CHCH OH and average molecular weight ranging from 134 through 4000, possess unexpected excellent properties as additives for rolling aluminum sheet and foil when dissolved in light petroleum oils and distillates having viscosities ranging between 30 and 80 Saybolt seconds, universal, at 100 The lower members or the polypropylene glycol series (below 750 average molecular weight) are almost completely insoluble in the usual light mineral oils and distillates used for rolling aluminum. One of the purposes F., the viscosity preferably being between 30 and 60 Sayof the fatty alcohol in the mixture is to provide a coupling bolt seconds, universal, at 100 F. action, thus providing mutual solubility of the glycol and Fatty alcohols are produced by high pressure catalytic mineral oil. hydrogenation or sodium reduction of fatty acids or fatty Typical compositions according to the invention are acid esters derived from fats. The commercial grades of given in Table 1.

Table 1 [Components, parts per 100, by weight] Composition No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1s 19 20 Name of Component:

00ml. Lauryl Ale 3 Coml. Oleyl Alc. Tallow Alcohol 3. 95 3.825 3. 05 3.3 2. 6 3 12 1. 5 .75 Dipropylene Glycol.. 1 Polypropylene Glycol 150. .05 .175 .35 0.7 .5 .25 Polypropylene Glycol 425. Polypropylene Glycol 1025 Polypropylene Glyc0l3000 Kerosene, 31 SUS, 100 F Light Mid. Oil, 37 SUS,100 F. 90 96 96 96 96 96 9e 90 84 92 9s 09 Light Min. Oil, 58 SUS, 100 F 96 fatty alcohols are mixtures of several different alcohols, reflecting the mixtures of fatty acids in the fat from which they were derived. Thus, in the terminology of these materials, we have mixtures known as coconut or tal- The mixtures of fatty alcohols and polypropylene glycols of our invention are unique in that the combination of the materials is a better lubricant than equivalent concentrations of either the fatty alcohols or the polypropylene glycols alone. The following Table 2 illustrates this phenomenon. The data were obtained under actual rolling conditions, rolling aluminum strip of the thickness indicated on a rolling mill equipped with instruments for measuring rolling loads. The comparative figures given are reductions in thickness of the strip, in one pass, at constant rolling load, as indicated. Reduction under these conditions is a direct function of decrease in friction caused by the lubricant.

Table 2 COMPOSITION, BY TYPE OF ALCOHOL, PERCENT Chain Coml. 00ml. Coml. Alcohol Length, Lauryl Oleyl allow Carbon Ale. Ale. Ale. Atoms Y Arachidonyl the highest member of the homologous series now in commercial production. Typical specifications of a few members of this series follow:

AVERAGE MOLECULAR WEIGHT Specific Gravity, 20/20 C 1. 0245 1. 0114 1. 004 1.0070 1.001 (25C) (25C) Viscosity, Centistokes,

210 F 3. 0 4. 5 7.8 10. 9 50.9 Flash Point, F 250 385 495 420 440 Solubility in Water, 20 0,

percent 0. 2 0.1 Solubility in Heptane, 20 0,

percent 1 Complete. 2 Insoluble.

Reduction, percent of .005

Rolling Load 5500 lbs. per in. of Strip Width 64 64 65 Comp. N0. 16 64 4 parts Polyprop. Gly. 1025, parts Light Min. Oil, 37 SUS 59 4 parts Polyprop. Gly. 3000 in 96 parts Same Oil 61 4 ;())arts Tallow Alcohol in 96 parts Same Oil 58 4 parts Palm Oil, 96 parts Same 58 4 parts Lanolin, 96 parts Same Oi 59 Light Mineral Oil alone, 37 SUS. 47

Reduction, Percent of .0033 in Aluminum Alloy 1100 Rolling Load Rolling Load 5200 lbs. per 7500 lbs. per in. of Strip in. of Strip Width Width Comp. No. 4 52. 7 59. 2 4 parts Tallow Alehol, in Light Min. Oil,

37 SUS (Saybolt seconds, universal) 50.6 55. 5

Lubricants of our invention are more efiicient for rolling aluminum strip than the commonly used fats or fatty acid esters in a number of cases of rolling, using various gauge aluminum, various loads and various base oils, as the following Table 3 shows:

Comp. No. 3 Comp. No. Comp. No. Comp. No. Comp. No. 4 parts Palm Oil, in Light Min. Oil, 37 SUS 4 parts Butyl Stearate, in

Light Min. Oil, 37 SUS- 4 parts Lanolin, in Light Min. Oil, 37 SUS Light Min. Oil, 37 SUS, No

Additive Comp. No. 8 4 parts Palm Oil, in Light Min. Oil, 58 SUS 4 parts Butyl Stearate, in

Light Min. Oil, 58 SUS '4 parts Lanolin, in Light Min. Oil, 58 SUS Light Min. Oil, alone, No

Additive For comparing a range of concentrations of our lubri- The effect of additions of polypropylene glycol to a fatty alcohol in improving the lubricating properties is shown in the following Table 5, with reduction as a function of percent glycol, in a typical alcohol and glycol mixture. The total mixture was held constant at 4 parts by weight in a light mineral oil, 37 SUS at 100 F.

Table 5 Percent Polyprop. Reduction, Per- Glycol 150 in a cent, of .0033 in. Mixture of Tallow Aluminum Alloy Alcohol and 1100, Rolling Load Polyprop. Gly. 150 7800 lbs. per in. of

Strip Width A definite improving effect of glycol content is noted at the initial addition level of 1.25%.

Some of the novel lubricant additive mixtures of our invention are superior also from the anneal stain point of 25 view. As mentioned previously, an excellent criterion of freedom from anneal stain is the boiling range of the material in question. Since the removal of lubricant from the aluminum sheet or foil during the heat treating cycles is essentially a distillation process, we have used distil lation tests as a means of comparing their staining tendencant mixtures and a commercial product, we have chosen a typical ratio of alcohol to glycol, as described below. This has been compared to the same concentrations of butyl stearate, in a typical base oil, a light mineral oil,

viscosity 37 SUS at 100 F.

cies. We list below in Table 6 the temperatures at which the indicated percentages of materials were distilled and the quantity and type of residue, if any, which remained in the flask when distillation was complete. dues denote the relative staining quality at the final tem- These resi- Table 6 F.) Temperature of Liquid at Which Indicated Percent of Volume was Distiller. (Atm. Pressure) Composition Init. 10% 50% End Residue B. P. Pt.

4 arts Coml. Lauryl Ale., 1 part 480 495 525 545 570 595 670 None.

Polyprop. Gly. 150. 3%itsllallowAlc lpart Polyprop. 503 532 593 626 649 680 785 Do.

y. 50. Polyprop.Gly.150 464 468 491 527 536 545 549 Do. ButylStearate 670 685 710 735 735 775 875 Moderatie1 Carbon and arms Palm Oil 750 775 815 850 885 935 Very large amts. Carbon andResidue. Kerosene 390 400 410 425 435 440 460 None. Light Min. Oil, 37 SUS 520 528 545 565 590 597 615 Do.

Table 4 Reduction, Percent of .0033 in. Aluminum Alloy 1100, Rolling Load 6500 lbs. per Concentration in. of Strip Width of Additive in Light Min.

Oil, Mixture: 3 parts Tallow Alcohol; Butyl 1 part Polyprop. Stearate Gly.

peratures indicated. However, since much aluminum annealing is performed at temperatures below the final temperatures indicated in some cases, those materials with abnormally high end points on distillation would be unsatisfactory because of undistilled liquid residues which In this work, a neutral (natural gas) atmosphere was employed in line with the common practice in the industry. pheres had been employed, the results would have been different with, in most cases, more residues and higher 70 final distillation temperatures.

Several comparisons can be drawn from these data. Since light mineral oils are invariably used, there would be no advantage in using an additive having a lower boiling range than they exhibit. It is desirable that the addi- 75 tive approach as closely as possible to the limit which 65 remain on the sheet surfaces.

It oxidizing atmosthese oils set so that higher anneal temperatures need not be maintained simply to drive olf additives present on the finished sheet. This i the fault from which fats and fatty esters suffer, as can be seen. Their end points in distillation are so high that operators are forced to heat their product much above temperatures necessary to heat treat the aluminum. These practices, of course, are wasteful and expensive of times and eflicient use of the furnaces.

According to our invention, the lubricant comprises an additive dissoived in a light petroleum oil or distillate having a viscosity between 30 and 80 Saybolt seconds, universal, at 100 F., the additive constituting about 1 to 25%, by Weight, of the oil or distillate, the additive being a mixture of hatty alcohols of the general formula ROH, Where R is a straight parafinic chain of from 10 to carbon atoms, either saturated or partially unsaturated, and polypropylene glycol having an average molecular Weight between 134 and 4000, the polypropylene glycol amounting to about 1 to 75%, by weight, of the additive.

The invention is not limited to the preferred embodiment but may be otherwise embodied or practiced Within the scope of the following claims.

We claim:

1. A metal working lubricant consisting essentially of an additive dissolved in a light petroleum oil having a viscosity between and 80 Saybolt seconds, universal, at 100 F., the additive constituting about 1 to 25%, by weight, of the oil, the additive being a mixture of fatty alcohols of the general formula ROH, where R is a stnai-ght panaifinic chain of from 10 to 20 carbon atoms with not more than one double bond, and polypropylene glycol having an average molecular weight between 134 and 4000, the polypropylene glycol amounting to about 1 to 75%, by Weight, of the additive.

2. An additive for light petroleum oils and distillates to improve their lubricating properties, said additive consisting essentially of a nihiture of fatty alchols of the genernal formula ROH, where R is a straight parafiinic chain of from 10 to 20 canbon atoms with not more than one double bond, and polypropylene glycol having an average molecular weight between 134 and 4000, the polypropylene glycol amount to about 1 to by weight, of the additive.

3. A metal working lubricant consisting essentially of an additive dissolved in a light petroleum oil having a viscosity between 30 and Saybolt seconds, universal, at F., the additive constituting about 1 to 25%, by weight, of the oil, the additive being a mixture of fatty alcohols of the general formula ROH, Where R is a straight paraflinic chain of from 10 to 20 carbon atoms with no double bonds, and polypropylene glycol having an average molecular weight bet-ween 134 and 4000, the polypropylene glycol amounting to about 1 to 75 by weight, of the additive.

4. An additive for light petroleum oils and distillates to improve their lubricating proper-ties, said additive consisting essentially orf a mixture of fatty alcohols of the general formula ROH, where R is a straight paraffinic chain of from 10 to 20 carbon atomswith no double bonds, and polypropylene glycol having an average molecular Weight between. 134 and 4000, the polypropylene glycol amounting to about 1 to 75 by weight, of the addtiive.

References Cited in the file of this patent UNITED STATES PATENTS Jahn July 29, 1952 OTHER REFERENCES

Claims

1. A METAL WORKING LUBRICANT CONSISTING ESSENTIALLY OF AN ADDITIVE DISSOLVED IN A LIGHT PETROLEUM OIL HAVING A VISCOSITY BETWEEN 30 AND 80 SAYBOLT SECONDS, UNIVERSAL, AT 100*F., THE ADDITIVE CONSTITUTING ABOUT 1 TO 25%, BY WEIGHT, OF THE OIL, THE ADDITIVE BEING A MIXTURE OF FATTY ALCOHOLS OF THE GENERAL FORMULA R-OH, WHERE R IS A STRAIGHT PARAFFNIC CHAIN OF FROM 10 TO 20 CARBON ATOMS WITH NOT MORE THAN ONE DOUBLE BOND, AND POLYPROPYLENE GLYCOL HAVING AN AVERAGE MOLECULAR WEIGHT BETWEEN 134 AND 4000, THE POLYPROPYLENE GLYCOL AMOUNTING TO ABOUT 1 TO 75%, BY WEIGHT, OF THE ADDITIVE.