United States Patent COLD WORKING LUBRICANT FOR WIRE AND THE LH E Richard L. Carhart, Lockport, 11]., assignor to United States Steel Corporation, a corporation of New Jersey No Drawing. Application November 2, 1950, Serial No. 193,761

6 Claims. (Cl. 252-18) This invention relates to an improved lubricant for use in cold working wire and the like and is a continuationin-part of my copending application, Serial No. 633,259, filed December 6, 1945, and now abandoned.

The invention has among its objects the provision of a lubricant which may be used as a Wire drawing lubricant as well as a lubricant which may be applied as a coating on wire or rod which is to be cold deformed into nails, bolts, etc. Further, the lubricant of the present invention imparts a distinctive coating to the wire, such coating in some instances supplanting sull coating.

These and further objects of the invention will become more fully apparent in the following description.

Although the lubricant of the present invention is useful and displays advantages over the prior art lubricants in various applications where wire is cold worked, the invention will be particularly described, for purposes of illustration, in connection with the forming of Wire nails from drawn wire.

Substantially all modern automatic nail making machines have much the same principle of operation. They accomplish the forming of the nail by five operations which are: the forming of a head on the entering end of the wire, the subsequent feeding of a predetermined length of the headed wire into the machine, pinching the wire to form serrations under the head, cutting off the wire and forming the point, and expelling the nail from the machine. It is desirable that the wire as drawn, without intermediate cleaning and coating operations, be fed directly into the wire making machine, both for reasons of economy and for the lubrication of the various metal forming portions of the machine by reason of the thin coating of wire drawing lubricant remaining on the wire. Difificulty has been experienced, however, in nail forming machines working upon wire which has been drawn with a solid soap, such as a solid metal soap, as the wire drawing lubricant, because such thin coating of soap on the wire tended to be rather viscous and when scraped off the wire eventually to gum up the various dies of the machine. As a consequence, when employing wire so drawn, the nail making machines had to be stopped and cleaned of such lubricant rather frequently.

The present invention provides a novel wire drawing lubricant which is of such character that it is non-viscous and does not tend to gum up or clog the machine even though it may be eventually scraped off the wire during operation of the machine. In addition, the lubricant remaining on the wire after drawing is such that it lubricates the forming and cutting dies of the nail making machine more efliciently, thereby resulting in a noticeably increased operating life of such dies.

The lubricant of the present invention consists of a dry mixture of a water insoluble metal soap, ferrous or ferric sulphate having water crystallization, and a filler substantially inert with respect to the Wire. More specifically, the lubricant consists of from 8 to 35% by weight of a water insoluble metal soap, from 20 to 80% by weight of ferrous or ferric sulphate having water of crys- 2,736,699 Patented Feb. 28, 1956 "ice 2 tallization, and from 10 to 45% of a filler substantially inert with respect to the 'wire. Among the water insoluble metal soaps which may be employed in the lubricant are the stearates of calcium, zinc, aluminum, magnesium, lead, and the like, all of which are insoluble in water. The ferrous or ferric sulphate employed should be one containing a substantial amount of water of crystallization, that is, ferrous or ferric sulphate, each molecule of which has four or more molecules of water of crystallization. If ferrous sulphate is used, it may range between and include FeSO4'4HzO and FeSO4-7H2O. If ferric sulphate is used, itmay range between and include Fe2(SO4)3'4H2O and-Fe2(SO4)s-9H2O. Either ferrous or ferric sulphate maybe used as desired since each imparts the same properties to the resultant lubricant as will be explained more fully hereinafter. The filler employed should be a finely divided substance, substantially inert with respect to the wire, which has the function of extending the lubricant. The filler should also be one which does not act as an abrasive to thus cause undue wear on the wire drawing dies or the dies in the cold forming machines. pable of reacting withand'satisfying the sulphate radicalof the ferrous or ferric sulphate as will be explained more fully hereinafter. I have found it preferable to use, for this purpose, lime (CaO) and calcium carbonate (CaCOs) which may be used in the total amount indicated, either Example I Percent FeSO4-7H2O 50 Calcium stearate 21.5 CaO 11 CaCOs 17.5

Example II Percent Fe(SO4)3-9 H2O 50 Calcium stearate 21.5 CaO 11 CaCOz 17.5

The lubricant is prepared simply by mechanically mixing the several ingredients together in dry condition. It is used in the wire drawing method to lubricate the wire in at least the last die, or the last series of dies, the Inbricant being put in the die boxes of the wire drawing machine in the dry mixed condition. Preferably, the wire before entering such die boxes is provided with a surface which will readily pick up and retain such lubricant, as for instance, by having been lime coated and baked in the customary manner. In addition to performing Well as a lubricant in the wire drawing operation, the composition of the present invention results, as stated above, in particularly good operation of a subsequent wire forming machine.

Wire coated with such composition and drawn has a reddish brown coating thereon, somewhat resembling the well known sull coating. Such coating differs, however, from a sull coating in that in the present method the base metal, that is the wire, is not actually oxidized as in the sulling method. The coating is believed to contain ferric hydroxide (Fe(OH)a), such ferric hydroxide The filler material must also be caresulting from a conversion of FeSO4 with water of crystallization to ferrous hydroxide (Fe(OH)2) under the heat and pressure of the wire drawing operation, the Fe(OH)2 then being oxidized to Fe(OH)3 where ferrous sulphate is used. When using ferric sulphate with water of crystallization the heat and pressure of the wire drawing operation will convert the ferric sulphate directly to ferric hydroxide (Fe(OH)3) because the ferric sulphate is already more highly oxidized than the ferrous sulphate. In order to convert either the ferrous or ferric sulphate to the hydroxide it is necessary that the sulphate radical of the ferrous or ferric sulphate be satisfied by combining with the metal radical of the filler material to form a compound such as calcium sulphate when lime (CaO) or calcium carbonate (CaCOs) is used as filler materials.

The lubricant of my invention is highly satisfactory for use as a coating medium for wire which is to be generally used in the manufacture of cold formed products, such as nails, bolts, screws, etc. The coating resulting from the use of this lubricant afiords excellent lubricating propcrties for cold forming operations and at the same time does not adhere to the surfaces of the forming dies and thus prevents clogging thereof.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. A cold working lubricant for wire or the like comprising a mixture of from 8 to 35% water insoluble metal soap, from 20 to 80% of a substance from the group consisting of ferrous sulphate, ferric sulphate and a combination thereof, each molecule of said ferrous sulphate and each molecule of said ferric sulphate having at least four molecules of water of crystallization, and from 10 to 45% of a filler compound having ametal radical which is above ferric iron in the electrornotive series and which will satisfy the sulphate radical of said ferrous sulphate and the sulphate radical of said ferric sulphate, said filler being substantially inert with respect to the wire and being a compound from the group consisting of the borates,

silicates, phosphates, carbonates, chromates, hydroxides, oxides, and sulphides of metals which are above ferric iron in the electromotive series, the percentages being by weight.

27 A cold working lubricant for wire or the like comprising a mixture of from 8 to 35% Water insoluble metal soap, from 10 to of a filler from the group consisting of CaO and CaCOs, and from 20 to of a substance from the group consisting of ferrous sulphate, ferric sulphate combination thereof, the percentages being by W t, it molecule of said ferrous sulphate and each molecule of said ferric sulphate having at least four molecules of Water of crystallization.

3. A cold working lubricant for wire or the like comprising a mixture of from 8 to 35% water insoluble metal soap, from 10 to 45% of a filler from the group consisting of Cat) and CaCOs, and from 20 to 80% FeSO4 each molecule of w iich has at least four molecules of water of crystallization, the percentages being by Weight.

4. A cold working lubricant for wire or the like comprising a mixture of from 8 to 35% water insoluble metal stcarate, from 10 to 45% CaO, and from 20 to 80% FeSOi each molecule of which has at least four molecules of Water of crystallization, the percentages being by weight.

5. A cold working lubricant for wire or the like comprisin a mixture of from 8 to 35% Water insoluble metal stearate, from 4 to 17% CaO, from 6 to 28% CaCOa, and from 20 to 80% FeSO4 each molecule of which has at least four molecules of Water of crystallization, the percentagcs being by weight.

6. A cold working lubricant for Wire or the like comprising a mixture of from 8 to 35% calcium stearate, from 4 to 17% CaO, from 6 to 28% CaCOg, and from 20 to 80% FeSO4-7HzO, the percentages being by weight.

Elder June 19, 1934 Pink Mar. 14. 1950