US 2565938 A
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Patented Aug. 28, 1951 k LUBRIOAN T METAL-ROLLING COMPOSITION Robert C. Williams, Columbus, Ohio, assignor to The Ironsides Company, Columbus, Ohio, a corporation of Ohio No Drawing. Application May 11, 1949, Serial No. 92,729
The present invention relates generally to lubricating materials or compositions, and more particularly to an improved lubricant composition for use with metals undergoing various types of forming operations, such as gauge reduction between the rolls of a cold-rolling mill.
In the past, the generally accepted material used as a lubricant for metals undergoing rolling operations was palm oil, or a mixture of palm oil with other materials or ingredients, such as certain liquid hydrocarbon vehicles or solvents. The primary objections to the use of palm oil as a lubricating material stem from the fact that this material is generally an imported product whose availability and cost are subject to extreme fluctuation, and whose physical properties and chemical composition are subject to relatively wide variation. A major disadvantage in the use of palm oil as a lubricant material for metal rolling operations is caused by a relatively wide variation in the free fatty acid content of different shipments or batches of palm oil as received at the import market. As is well known, the free fatty acid content of imported palm oil may vary generally between approximately ten per cent and upwards of thirty-five per cent, depending upon the time interval between production and use and the temperatures to which the same has been subjected during production, storage and use; it being understood that the free fatty acid content of palm oils generally increases due to a breaking down of the natural vegetable fats and fatty acid compositions during sustained periods of storage, particularly wheresuch storage is eifected in relatively high temperature climates.
It will be manifest that a relatively high free fatty acid content within a lubricant rolling material is particularly disadvantageous for use with metalswhich are intended to undergo plating or tinning operations after rolling, due to the fact that such metals are generally subjected to cleaning or washing operations with relatively strong alkalies or bases, such as sodium hydroxide, which react with free fatty acids to form soaps or certain saponification products Which greatly interfere with the complete cleaning of the metal preparatory to tinning or plating operations.
Furthermore, palm oils have a natural tendency to break down under relatively elevated temperature conditions, such as are encountered during rolling operations, and thereby form or produce an excess of free fatty acids which, in the event that the palm oil is used with an emulsify-r 6 Claims. (01. 252-57) ing agent, oftentimes causes an imbalance of the emulsifying agent, resulting in an unstable emulsion.
It is, therefore, the primary objective of the present invention to provide a lubricant composition for use in metal rolling operations which possesses improved operational characteristics over previously accepted palm oil compositions and which may be produced from relatively inexpensive land readily available materials at a fraction of the cost of palm oil or palm oil compositions, and which may be easily compounded and supplied to the user with a predetermined.
desired percentage of free acids.
It is another object of this invention to provide a lubricant rolling composition whose free acid content may be critically controlled so as to fall within ranges desired for various types of metal-forming operations, and particularly where metals are to undergo subsequent plating or tin ning operations.
It is still a further object of this invention to provide a lubricant composition for metal-forming operations which may be supplied to the user with a more or less definite and known acid content without requiring the user to resort to time-consuming and expensive analyses of the lubricant material prior to its use to determine the percentage of acid content therein or to take steps to adjust the acid content prior to the use of the material.
Yet another object of the present invention is to provide a lubricant composition which may be compounded from an inexpensive by-product of a pulp paper-making process, known as tall oil, which has a relatively high and stable free acids content and a solid fat material, such as the better grades of beef or mutton tallow, which are solids at ordinary room temperatures, and which perferably have a free fatty acid content ranging from less than one to five percent and well below the range of acid content of the tall oil, whereby a simple proportional compounding of these two separate ingredients results in end products of buttery consistency having desired and known percentage ranges of free acids commensurate with the requirements of various metal-forming operations.
The present improved lubricant composition comprises an intimate and homogeneous mixture of a normally viscous liquid material (at ordinary room temperatures), known as tall oil, and a normally solid (at ordinary room temperatures) animal or hydrogenated vegetable fat or oil having a free fatty acids content not to exceed 5 3 percent by weight of the fat or oil and a titre point ranging between 27 C. and 45 C.
Tall oil is a viscous oily liquid at ordinary room temperatures and is obtained as a by-product from the wood of coniferous trees during the process of conversion of the wood fiber into cellulose by the sulphite paper-pulp process. It is a mixture of rosin acids and fatty acids with a small percentage of higher alcohols and generally has a free acids content ranging from 80. to 95 percent by Weight of the material.
Preferably, a high grade beef or mutton tallow is used as the principal ingredient ofthc present lubricant composition, although certain grades of other solid animal fats or oils, such as horse sufiiciently to be solid at ordinary room temperatures, may be employed with substantially equal results. It will be understood, however, that the animalor vegetable-fat. on oil. ingredient should have a relatiyelyjlow freeiiattyacids.content, preferably ranging from less than one. to four percent by. weight of the materialand not to exceed five percent. by. weight. Also, the animal, or vegetable fat or oil. used must be solid at ordinary room. temperatures (approximately C. to C.) and preferably has a titre or solidification range of from 27 C. to45 C.
, It has been found that lubricant rolling com positions used in the cold rolling, of, sheet metal to effect gauge. reduction of. the metal should preferably have a semi-solid, buttery consistency, and a relatively low free. acids content, preferably ranging from 6 to I L-percent by. weight of the lubricant composition. This limitation upon the percentage of free acids, particularly fatty androsin acids; is necessitated by the; fact that an excessive amount of free fatty or'rosin acids in alubricant rollingcomposition forshcet metals results in the formation of excessive. amounts of soaps or other saponification products when the sheet metal is subjected'to washing or cleansing prior to tinningor plating operations with caustic alkalies or bases, such as sodium hydroxide, or. alkaline salts, such. as sodium phosphates, which washing; or cleansing operationsare more orless standard practice in. preparing sheet metal for tinning operations aiterrolling. It has further been found that lubricant compositions or materials having a free acids content higher than approximately lcpercentby weight, when used in conjunction witlran emulsifying," agent for application to the. metal as an emulsion, tend to causeinstability within the emulsion which results in inefficient lubrication of the metal during. forming operations.
Hence, it is the ordinary practice of the metalforming industry, and particularly rolling mills, to specify that lubricant materials. or compositions be supplied which have a free. acids con" tent not to exceed. 15 percent by weight of the composition, and preferably in two. ranges, namely: 6 to 8: percent and. 1G to 14 percent, and a semi-solid or. buttery consistency in order.
that thevv same may be applied to. the metal. in av number of diiierent ways consistent with. the particular type of work beingdoneain' arrefidcientand. economicalmanner.
As a specific example of the-production of the present lubricant compositionto yield: an. end
product having a free'acids content-within the: range of 6 to 8 percent'by weight of the compo sition, 96 pounds of:beef7tallow having:a titrebr solidification pointxotapproximatelyt'l" C. and
a free fatty acids content of 3 percent by weight were blended at approximately 50 C. with 4 pounds of tall oil having a free acids content of percent by weight. The mixture was then allowed to cool to ordinary room temperatures (approximately, 25 C.) to provide 100 pounds of a buttery solid'lubricant composition having a total acids content of 6.28 percent by weight of the composition. It will be noted that this figure of 6.28 percent iswell within the desired lower range of6 to 8" percent of free acids, and allows for a slight increase in the percentage of free acids, suchas-mightbeoccasioned by prolonged storage of the material at relatively elevated temperatures prior to use of the material without exceedingthe desired upper limit of 8 percent.
.As an example of the compounding of the present lubricating composition to provide a total free acids content within the aforementioned desired higher range, viz. 10 to 14 percent, poundsof beef tallow having a titre polnt'of approximately 3'? (31 and" a free fatty acids content of 3 percent byweightwereblended with 10 pounds ofta'll oil having an averag free acids content of 85 percent by weight at approximately 50 C. Afterc'oollngto room temperatures, the mixture yielded pounds of a homogenous buttery solid composition having'a total' free acids content'of' 11.2percent Icy-weight of the composition.
Thus it will'be seen from the foregoing data that by'a' relatively. simple proportional compounding of the two. ingredients, preferably beef tallow and tall' oil, which have known acid values. the present lubricant composition may be supplied. in the desired ranges for total fre acids content. It will be understood that should it be desired that the composition have anexact or specific free acids content within the rangeof 6' to 14 percent, the requirements for such an exact content may, beeasily satisfiedby a simplemathematical determination of the amounts of the separate. ingredients required, knowing. the acid value thereof, and thereafter by blending the predeterminedamountstogether.
Ithas been foundv that the present lubricating. compositionhaving, a free acids content ranging. between :6 and 15' percent hasgiven excellent results when used gs a. lubricant in metal rolling operations where gauge reductions of the order of 65- percent have been-effected when operating. upon relatively hard metals,. such as double A: chrome steel. The present lubricant composi-- tionis further characterizedby its ability to Withstand the relatively extreme high pressures encountered. during. rolling. operations without breaking dcwnto yield an undesirabl high percentage of freeiatty or rosin acids which greatly" impede subsequent tinning or plating operations the same undergo? final finishing or pinch roll-- ing operations.
Inuse, the present lubricant composition may be applied. in'its buttery solid form to the sheets of metal or 'the rollsof the rolling mill prior to or during" rolling operations by'drip'ping or sprayingv t the same -thereon, by dipping the sheet metal-into the composition, or by placing aquan-- mill.
tity of the composition within a porous fabric or cloth bag and thereafter permitting the bag to Wipe the surface of the sheets or rolls during rolling operations. The present composition may also be applied to the metal or the rolls of a mill in an emulsion form in water, where either mechanical agitation or an emulsifying agent is employed to maintain the material in its emulsified condition. Further, the present lubricating composition may be diluted or cut with a suitable hydrocarbon solvent or liquid vehicle, such as kerosene, and applied in liquid form to the metal prior to or during rolling operations.
In view of the foregoing, it will be noted that the present invention provides an improved and versatile lubricant rolling composition for use with metals undergoing forming operations, such as gauge reduction between th rolls of a rolling The present composition is characterized by its ability to be compounded from relatively low cost and readily available domestic materials which, when combined in definite relative proportions, produce a composition whose properties excel the highest grades of imported palm oils as a lubricant for metal-forming operations. The present lubricant is further characterized by the fact that the same may be supplied with a relatively low, known, and stable free acids content in comparison with the oftentimes high and extremely variable free acids content of imported palm oils or palm oil compositions, thereby enabling the present composition to be used as a lubricating material for metals which are intended for subsequent tinning or plating operations which require that the metal be relatively free from free acids, without resorting to expensive and time-consuming analyses to determine the acid content of the lubricant prior to its use and thereafter taking steps to adjust the acid content of the lubricant to adapt the same for particular uses. Another important advantage to the use of the present composition stems from its physical property of being a buttery or pasty solids material at ordinary room temperatures, thereby enabling the same to be efliciently and economically applied to the metal undergoing forming operations in a, variety of ways.
1. A lubricant composition for metals undergoing forming operations consisting essentially of a non-flowing mixture of 1 to 17 parts of tall oil having a free acids content of from 80 to 95 percent by weight with 83 to 99 parts of a fat normally solid at ordinary room temperatures having a free fatty acids content not to exceed 5 percent by weight and a titre point ranging Tall 011, 1 to 17 parts Solid Fat, 83 to 99 parts the said composition having a total free acids content of 6% to 14% by weight thereof.
3. A lubricant rolling composition of solid non-flowing consistency having a total free acids content of 6% to 14% by weight of the composition and consisting essentially of a homogenous mixture of from 83 to 99 parts by weight of tallow having a free fatty acids content of from 1 to 5 percent by weight and from 1 to 17 parts by Weight of tall oil having a total acids content of from to percent by weight.
4. A lubricant rolling material of solid nonflowing consistency having a total free acids content of from 6 to 8 percent by weight of the material and consisting essentially of a mixture of 4 parts by weight of tall oil and 96 parts by weight of a tallow having a free fatty acids content not to exceed 5 percent.
5. The composition set forth in claim 2 emulsified in aqueous solution.
6. The composition set forth in claim 2 diluted with kerosene.
ROBERT C. WILLIAMS.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 8,176 Selgrath June 24, 1851 1,919,125 Patch July 18, 1933 2,258,552 Harris Oct. 7, 1941 2,270,319 Lieber Jan. 20, 1942 2,326,387 Nill Aug. 10, 1943 2,377,106 Reswick May 29, 1945 2,417,283 Zimmer Mar. 11, 1947