US2286433A - Drawing compound - Google Patents

Description

Patented June 16, 1942 UNITED STATES PATENT OFFICE DRAWING COMPOUND James E. Montgomery, Highland Park, Mich.

No Drawing. Application August 23, 1939, Serial No. 291,617

8 Claims. (Cl. 252-14) This invention relates to drawing compounds. Compositions of ingredients referred to as drawing compounds herein are generally employed in the art of metal formingand in use are interposed between the surface of a metal being 5 formed and the configurating means employed in the forming operation.

Drawing compounds which are the subject of this invention contain new and different ingredients as film fortifiers than have heretofore been employed in drawing compounds and have the particular property of more effectively permitting and aiding metal being formed to undergo more or less cold plastic flow when subjected to heavy pressures or to a combination of lateral .tension 1 and heavy pressures usually applied by a configurating device to a work piece during the forming thereof.

Many compositions have been used heretofore to promote cold plastic flow in the art of configurating metal under pressure by means of dies and the like. Some of the prior art drawing compounds have consisted of but a single ingredient, others have contained two or more ingredients. Certain of the added ingredients introduced into the drawing compounds of the prior art provided new functions and properties.

Examples of prior art drawing compounds having but a single ingredient are those consisting of oils. Where the applied pressure is comparatively light and the resultant cold plastic flow expected and obtained is of a comparatively small degree, petroleum oils have proven quite satisfactory inasmuch as they allow slippage of the work face past the tool face and are capable of maintaining during the metal forming operation a lubricating film separating the work face and the tool face. However, as the pressure employed in the metal configurating operation increases, it has been common to employ animal and vegetable oils naturally containing a small percentage of free fatty acid which serves to anchor a film to both the work face and the tool face whereby to permit a considerable increase of pressure in the metal drawing or configurating as film fortifiers for the purpose of mechanically holding apart the work face and the tool face,

generally in metal configurating operations. The solid particles employed were at first mineral in nature and were selected from the class known as solid lubricants, for example graphite, which is both comparatively soft and slippery.

Although better results were obtained by the use of compositions containing solid lubricants, the incidence of scrap in metal forming operations still remained high. Study of this condition in sheet drawing lead to the conclusion that the fault lay in the manner of lateral extension of sheets during the drawing thereof.

In deep drawing operations, the work stroke of the male die forces the work sheet to be deformed plasticallyto conform to the configurations of the drawing cavity of the female die. During deformation considerable lateral tension is exerted on the work piece causing the peripheral portions thereof to move toward the drawing cavity. Deep drawing cannot be successfully accomplished if such movement is uncontrolled, therefore, the periphery of the work piece is held by initially adjustedforce against the face of the female die adjacent the cavity therein by means of draw-rings or the like. The hold-down pressure exerted by the draw-ring maintains a lateral tension in the work piece and, given proper lubrication, the work piece is fed evenly to the drawing cavity during the work stroke of the male die. The lateral movement of the piece being deformed is thus controlled by the amount or rate of feeding from under the draw-ring, the primary results being a more even cold plastic flow of the work piece.

thus permitting the use of greater pressures 53 At one time maximum lubrication had been sought as a property of drawing compounds, however, research disclosed that excessive lubrication renders diflicult the maintenance of the adjustment of the draw-ring pressure in deep drawing operations, undue slippage caused by excessive lubrication making the uniformity of the rate of feeding of a work piece from under the drawring quite impossible. This was found to be extremely important inasmuch as irregularity of rate of feed from under the draw-ring in deep drawings operations caused buckling, tearing, pickups and hard spots from overstraining the metal being drawn.

The film fortifiers which were first selected from solid mineral lubricating material were later replaced by film fortifiers of mineral particles intermediate in hardness between the hardness of the work face and the hardness of the hardened tool face in metal forming operations on the theory that such particles become em- I bedded in the work face and rode the tool face during the metal forming or configurating operation. This was a step forward in sheet drawing operations in that it secured a much more uniform rate of work feed than heretofore had been possible and, in general, a deeper draw was permitted and a reduction in scrap was accomplished. However, a new problem developed,

namely, the mineral particles employed as film fortifiers embedded themselves in the work face and were difficult to remove from the surface of the work piece by means of the usual subsequent cleaning operation employed, and the finish of the sheet after cleaning tended to be dull.

In order to meet demands for deeper drawing in sheet drawing operations, and to permit greater cross-sectional reduction in tube drawing, wire drawing and the like, and to obtain greater brightness of finish of the work piece after configurating, much research and study of the problem was undertaken which resulted in the instant invention.

It has been found that a suspension in an oleaginous medium of certain finely divided proteins and proteinous materials containing substantially no added water, the proteinous particles will elastically compress under heavy pressures to a thin yet discrete form capable of serving as a film fortifier to maintain a positive separation of metallic surfaces when interposed therebetween in metal forming andconfigurating operations, and, upon release of the pressure exerted by the dies on the work piece, the proteinous particles therebetween tend to revert to their prior form and do not plastically adhere to the metal surfaces whereby the Work face is left in a bright, easily cleaned condition.

Where proteinous particles are employed in drawing compounds, they impart an even sliding action between dies and work being configurated and will not permit a metal to metal lock. The proteinous particles are not soluble in oil, but due probably to being derived from oil-bearing plant parts, they have the property of carrying oil most tenaciously, still retaining two or three per cent when compressed under heavy pressures. However, they are not fused by the heavy pressure and tend to reabsorb the expressed oil after the release of the pressure applied thereto.

The finely divided proteinous particles, when used in oleaginous carriers as film fortifiers in place of either solid mineral lubricants or solid harder, mineral particles, by virtue of their retained oil content which confers upon them compressibility without losing their discrete form, maintain lubrication efficiently at the greater pressures necessary for greatly increased cold plastic flow of the work metal desired or required in modern deep drawing operations. Comparative improvements are obtained in tube drawing, wire drawing and the like. I

- The applicant has found that certain finely divided organic preferably proteinous materials such as peanut meal, fiaxseed meal, soybean meal, pecan meal, cocoa bean meal, and the like supply particles which, although insoluble in oleaginous lubricants, are well wetted by them and form in them a stable internal phase capable of retaining an efilcient amount of such lubricants under heavy pressures encountered in metal drawing operations.

In the instant invention, the materials used as film fortifiers are preferably employed in their commercial forms which possess only small quantities of oil and contain substantially no added water.

Apparently lubricant is held around and in the proteinous particles by the same substances that retain the oil content natural to them, among such being lecithin and cholesterol. It is well known that when proteinous substances containing quantities of oil and other oleaginous materials have been subjected to heavy pressures in attempts to mold them into plastics, the oil content thereof prevents coherence, the mass behaving elastically and maintaining discreteness of the particles composing it as evidenced by the crumbling of the mass after release of pressure thereon. This non-coherence materially aids in producing the desirable effects obtained from the use of proteinous materials as film fortifiers in oleaginous lubricants in metal configurating operations wherein no evidence of plastic films remain on drawn work, the drawn surfaces being substantially bright and clear.

Although the use of proteinous materials have been found preferable, it is not intended to exclude from the scope hereof the use of other organic elastically compressible particles which are capable of maintaining discrete from under heavy pressures and which are not soluble in an oleaginous medium when employed in such as film fortifiers.

One example of a drawing compound particularly adapted for use in deep drawing of sheets comprises 1% to 50% by weight of finely divided peanut meal or its equivalent and 99% to 50% of vegetable, animal or fish oil of a fluid nature at normal room temperatures. The peanut meal is intimately mixed and dispersed throughout the oil medium. Such drawing compounds provide superior results to similar compositions containing petroleum lubricating oils.

Still another illustrative example of a drawing compound embodying the invention particularly adapted for use in deep drawing of sheets and in stamping comprises 1% to 50% by weight of finely divided peanut meal or its equivalent and 99% to 50% of neutral petroleum lubricating oil of a Saybolt viscosity of 100" to 750" at 100 degrees F. The peanut meal or its equivalent is intimately mixed and dispersed throughout the oil medium.

Another example of a drawing compound embodying the invention adapted particularly for use in deep drawing of sheets and the like comprises 5% to 50% by weight of finely divided peanut meal, fiaxseed meal, soybean meal, pecan meal, cocoa bean meal or the like intimately mixed with to 50% of powdered st'earic acid or its equivalent.

Another example of a drawing compound embodying the invention which may be successfully employed in deep drawing operations comprises 5% to 50% by weight of a meal of the class characterized by peanut meal admixed with 95% to 50% of camauba wax or any wax-like product which, when melted, has the physical properties of an oil-like liquid.

The two foregoing examplesof drawing compounds are preferably prepared as a finely ground or fiaked powder and are employed as an improvement over drawing compounds containing graphite -or other solid lubricants which have heretofore been used in extremely dimcult drawing operations. The compositions may be apphed by sprinkling directly upon the die or work surfaces or they may be admixed with an oily vehicle so as to Permit its application upon die paratus or soybean meal, pecan meal or work surfaces by brushing. When the compound is applied as a powdered mixture, the oleaginous constituent is melted to an oily liquid by the heat developed in the drawing operation and suspends the meal.

Anexample of a drawing compound embodying the invention particularly adapted for use in the cold drawing of tubular products and the like comprises 2% to by weight of finely di-. vided peanut meal or its equivalent and 98% to 80% of an oleaginous substance such as beef tallow of high free fatty acid content sufiicient to secure 7% to 20% of free fatty acid in the compounds. The peanut meal or its equivalent is intimately admixed in uniform dispersion with the tallow and the mixture placed in a large tub or vat suitably equipped with closed steam coils or the like for heating the same and a'suitable ap-' air line for maintaining continuous agitation. The temperature in the tub or vat is preferably brought to and maintained at 150 'degrees to 180 degrees F. Tubes to be drawn are dipped into the solution and allowed to fill within the bore and then completely drained. After draining, the inner and outer surfaces of the tubes remain coated with the tallow or the like through- "50% of. a proteinous out which is the dispersed and evenly distributed I finely divided peanut meal or its equivalent. As the oleaginous constituent drains away to a thin film, the tube or the like remains evenly wetted on all surfaces and evenly coated with the meal. The tube is allowed to cool to normal room temperature which causes the oleaginous constituent to adhere to the metal surface of the tube and bind the meal to the tube walls. The tallow or other oleaginous constituent acts as a lubricant for drawing and the meal performs the function of lubricant carrier insuring the passage of lubricant between the tube surfaces and the die surface during drawing. The meal further acts as a film fortifier preventing metal to metal contact. The novel drawing compound provides drawn .or formed tubes with a comparativelybrightsurface inasmuch as it permits a polishing action without allowing gummy adherence of the film fortifier to the tube walls, thus securing surface brightness of the tube being drawn.

An example of a drawing compound embodying the invention for use in cold wire drawing comprises 80% to 90% by Weight of finely divided peanut meal or its equivalent and 20% to 10% of soap powder. Another example preferably employed in the cold drawing of wire comprises 80% to 90% by weight of finely divided peanut meal or its equivalent and 20% to 10% of metallic stearates, oleates or the like. And still another example of a drawing compound embodying the invention particularly adapted for use in the cold drawing of wire comprises 80% to 90% by weight of organic meal from an oil-bearing source of the class which includes peanut meal, fiaxseed meal, and the like and 20% to 10% of lubricating substances of a wax-like nature such as stearic .acid, carnauba wax and the like.

Although but a'few illustrative examples have beengiven of drawing compounds embodying the invention in particular reference to their use in deep drawing of sheets, in metal stamping and sheet drawing generally, in the cold drawing of tubular products and the like, and in the cold drawing of wire, many other and various drawthan by comprising an intimate finely divided-proteinous -meal containing substantially no added wag ter of the class consisting of peanut meal, flax.- seed meal, soybean meal, pecan meal and cocoa bean meal, and 99% to of a neutral petroleum lubricating oil having a Saybolt viscosity of 100" to '750" at 100 degrees F.

2. A. drawing compound comprising an intimate mixture of 1% to 50% of a finely divided proteinous meal containing substantiallyno added water of the class consisting of peanut meal, fiaxseed meal, soybean meal, pecan meal and co-' coa bean meal, and 99% to 50% of an animal, fish or vegetable oil fiuidat normal room temperatures.

3. A drawing compound comprising 5% to meal containing substantially no added water of the class consisting of peanut meal, fiaxseed meal, soybean meal, pecan meal andv cocoa bean meal intimately mixedwith an oleaginous material which, when under temperature conditions incidental 'to a metal drawing operation, has the physical properties of an oily liquid.

4-. A drawing compound comprising 5% to 50% of a proteinous metal containing substantially no added water of the class consisting of peanut meal, fiaxseed meal, soybean meal, pecan meal and cocoa bean meal intimately mixed with carnauba wax.

5. A drawing compound comprising an intimate mixture of 2% to 20% of a finely divided proteinous meal containing substantially no added water of the class consisting of peanut meal, flexseed meal, soybean meal, pecan meal and cocoa bean meal, and 98% to tallow having high free fatty acid content! 6. A drawing compound comprising an. intimate mixture of 2% to 20% of a finely divided proteinous meal containing substantially no added water of the class consisting of peanut meal, fiaxseed meal,.soybean meal, pecan meal and cocoa bean meal, and 98% to 80% of beef tallow having afree fatty acid. content sufficient to secure 7% to 20% of free fatty acid in the compound. I

'7. A drawing compound comprising an intimate mixture of 80% to of a finely divided proteinous meal containing substantially no added water of the class consisting of peanut meal, fiaxseed meal, soybean meal, pecan meal and cocoa bean meal, and 20% to 10% of oleaginous material.

8. A drawing compound comprising an intimate mixture of 80% to 90% of a finely divided proteinous meal containing substantially no added water of the class consisting of peanut meal; fiaxseed meal, soybean meal, pecan meal and cocoa bean meal, and 20% to 10% of lubrieating substances of an oleaginous nature and normally solid except that under temperature JAMES E. MONTGOMERY.

ing compounds obviouslymay be made by those of beef