US2531553A - Upsetting-die lubricant for application to bolt stock or the like - Google Patents

Description

Patented Nov. 28, 1950 UPSETTING-DIE LUBRICANT i on ArrLIoA- 'rIoN 'ro BoL rs'rocK on THE LIKE Charles G. Canney, Worcester, Mass.,assignor to The American Steel and Wire Company of New Jersey, a corporation of New Jersey No Drawing. Application May 29, 1946, Serial No. 673,175

. 2 Claims.

This invention relates to improvements in lubricants for bolt stock to be subjected to cold upsetting.

In the manufacture of bolts, screws, rivetsand the like on cold heading machines, it is essential that the wire or rod from which such products are fabricated have a coating which will protect the tools of the headers, notably dies, from rapid or excessive wear by preventing direct contact of metal against metal.

In practice, it is essential that this coating fulfillcertain requirements. For example the coating should not clog the dies, nor become impregnated with foreign particles of an abrasive nature from the time the wire is made until it is used. Additionally, the coating must have the necessary lubricating qualities for wire drawing and heading die extrusion, and it must remain stable under varying conditions of temperature and humidity, and not decompose over long periods of time. Furthermore, the coating must act as an anti-rust agent with respect to the wire surface and also with respect to surfaces of the products from cold heading machines which are to be subjected to further processing at a later date, and

it must be easily removable from the surface of the formed products in preparation for plating while not leaving any foreign residue which requires excessive effort to remove after the headed capable of powdering away to a certain degree under deformation.

1 have invented a lubricant which satisfies the above requirements and a method of processing wire by the aid thereof. According to my invention, the wire is prepared in the following manner and sequence, expressed first in general terms, to be elaborated upon hereinafter. The general sequence of operations is:

1. Wire or rods are cleaned to remove scale, grease, or other foreign matter, following which a 2. light or heavy sull coat is applied, depending on the number of drafts to be made. Then a 3. light or heavy lime coating is applied, depending on the number of drafts to be made.

Next 4-, the coated rods or wire are dried, afterwhich v 5. the thus-coated rods or wire are drawn to finish size through a novel lubricant consisting of a mixture of grease identified as No. 2 consistency, and hydrated lime. The end result is a wire or rod surface on which is a layer of sull adjacent to the surface of the wire or rod, changing gradually to an external surface of asiillgrease-lime composite, comprising a very thin, brown, hard, glossy, tightly bonded coat.

The lubricant referred to in (5) above is composed of from approximately ten per cent to approximately thirty per cent of No, 2 consistency grease, and from approximately seventy per cent to approximately ninety per cent of fortifying agent, which may be lime, such as hydrated lime, borax, or hydrated lime mixed with graphite.

The No. 2 consistency grease referred to above is composed of approximately eighty-five per cent mineral oil and fifteen per cent soaps. To make the soap a definite amount of fats and fatty acids are saponified to soap by a converting agent, such 'as soda ash, or the carbonates or hydroxides of the alkali metal group or hydroxides of the alkaline earth metals, the saponification being carried out by heating the mixture of fats andsaponifying agent. The mineral oil and soap then are added together with agitation and heating until the soap disperses throughout the mineral oil in a homogeneous colloidal suspension. On cooling down, the resulting mass becomes gelatinous and forms the lubricating grease herein referred to. However, instead of saponifyingfats and fatty acids and mixing the resulting soap with the mineral oil in two steps, the mineral oil is mixed with the fats and fatty acids and the latter saponified in the presence of the mineral oil in a single kettle under elevated temperature and pressure to effect the colloidal dispersion of the soap in a single kettle, rather than to saponify in one kettle and suspend in another without the medium of pressure.

The following are some of the factors that influence the melting point, penetration value, and texture of the resulting grease: 1) the temperature. and pressure employed during manufacture; (2) the physical and chemical characteristics of the fats and fatty acids employed; and (3) the amount of soap combined with the oil. Thus, in the manufacture of greases, it is possible to have melting points up to 600 F., or penetration values down to 0. It is a matter of material selection and method of preparation.

The mineral oil employed in the production of No. 2 consistency grease has a gravity of 24 B., flash point,340 F., fire point395 F., viscosity 3 150 seconds Saybolt at 100 F. The properties and make-up of the No. 2 consistency grease are as follows:

Penetration 265-290 Melting point, (approx.) F 195 Moisture percent-.. 1-1.5 Free fatty acid do 0.2 Soap do Mineral oil do 85 Referring more specifically to steps 1 through 5, above, these generally expressed steps may be defined more specifically as follows, the steps being numbered to correspond with each step as numbered above:

1. Rods or wire first are cleaned in the conventional manner, such as in hot sulphuric acid maintained at a temperature of from 160 F. to 190 F. Instead of sulphuric acid, hot or cold hydrochloric acid may be used in the cleaning operation.

2. A sull coat then is applied to the wire, which may be either a light sull or a heavy sull. A light sull is applied by subjecting the wire to an atomized water spray for about twenty minutes. Such a sull coat will persist for two or three drafts of wire drawing. A heavy sull coat is applied to the wire by subjecting the wire to an atomized water spray for about sixty minutes. Such a heavy sull coat will persist on the wire for four or more drafts of wire drawing.

3. The sull coated rods or wire are then dipped in a bath of hot lime maintained at a temperature of from 180 F. to 200 F. This lime bath is an emulsion containing from four to five per cent lime and the rest water. The rods or wire are dipped in this lime bath for from one to two minutes. A heavy lime coat may be applied if desired by dipping the rods in a lime bath containin from approximatel seven per cent to approximately eight per cent lime and the remainder water, for approximately the same period of time.

4. The lime coated rods are removed from the lime tub and allowed to drip ofi, after which they are dried in a flash baker for five or ten minutes. If desired, the lime coated rods may be baked in a conventional baker which requires from three to four hours.

5. The rods or wire then are drawn through a die using the wire lubricant described above. The wire, after it is drawn a sufficient number of drafts, will have an amount of lubricant coated on its surface so as to give a desired predetermined finish.

This is a desirable quality in that it disperses any excess lubricant or that which is not essential for lubricity by powdering away and avoiding any tendencies to load or pit hammer or heading dies.

In the above-outlined procedure, step No. 2 provides for the application of a sull coat to the wire before it is dipped into the lime. If desired, this sull coat may be eliminated, but it has been found that when the sull coat is applied, the die life in the upsetting machines is practically doubled as compared with the die life when using non-sull coated rods or wire.

The coating or lubricant applied to the wire, as described above, has the following characteristics which are outstanding:

1. The coating or lu bricant has a pulverizing or flaking ability, that is, the coatin will flake setting operation. This is a. desirable quality in 4. that it disperses the coating after it has performed its function in protecting the upsetting dies so that it thereafter does not adhere to and clog up the dies.

2. The lubricant or coating has great mobility, that is, plasticity.

3. The lubricant has a, high surface tension which gives it a high film strength, that is, ability to resist friction. The lubricant has a higher film strength than the so-called lacquo finish obtained in accordance with the process of the United States Patent to Flint 0. Elder, No. 1,963,298, granted June 19, 1934.

4. The lubricant provides excellent protection against corrosion. It affords from approximately 400 to 500 per cent better protection against corrosion than is afforded by the lacquo finish described in the said Elder patent.

By virtue of my invention, the lime coating may be omitted in certain instances, in which event, the rods or wire to be drawn are cleaned, sullcoated as described above, passed through the above-described grease-hydrated lime lubricant. and drawn.

If desired, coloring matter may be added to the lubricant to provide distinctive identifying colors for the stock. Thus, for example, there may be incorporated in the lubricant from about three to eight per cent of a dye material, the coloring however having no eifect on the lubricating value of the lubricating composition.

In general the most severe wear on dies, either full faced dies or recessed faced dies, from the standpoint of critical tolerance area is the area around the die hole, that is, from several thousandths of an inch outside the hole beyond the radius down into the hole below the radius several thousandths of an inch. Insertion of the blank into the die may be made with a minimum of friction due to the smooth thin adherent coating. Such features of the coating also prevent blanks from sticking in the die and also permits making of long shanked work Where other lubricants would cause much difiiculty.

As the hammer delivers its blow, the blank effects a minute forward travel from the force of impact resulting in excessive friction potential on the die. It has been found that dies reach a constant temperature of approximately F. The No. 2 consistency grease described herein has a melting point approximately 45 higher than this, or approximately F., thus avoiding any major changes in its physical condition, which, under higher temperatures, causes the grease to go from the solid to liquid state which reduces coating efficiency by film strength depreciation. In addition to protection provided from the radius down into the hole by the lubricant in the solid state at this area, the plasticity of the coating is also effective in providing lubrication in that the smooth coating is not broken or ruptured and also permits extrusion of the shank. The condition of the coating at this pointfurther enhance die life by reducing Wear on the first 0.0005 inch of a new die hole where rapid opening is a normal expectancy of the said tolerance.

The area from the radius out on the face of the die or under the head of the work develops a relatively instantaneous temperature of 300 F. to 400 F., which changes the grease into a very soft state. Lubricative action "Ts bolstered by the presence of lime and sull which was incorporated in the coil described previously herein. In the case of recessed faced dies such physical condition is advantageous in that the corners of the die do not load up with lubricant which results in desirable sharp corners on the headed part.

Being an extremely smooth continuous adherent coating, the inability of moisture to break down the finish permits unusual long periods of warehouse storage without added protection, such as paper wrapping.

While the invention is described in detail above, it is not desired to be limited to the exact and specific materials and methods described, as there may be used such substitutions, modificacations or equivalents, as are embraced within the scope of the invention as embraced in the appended claims.

I claim:

1. A wire drawing lubricant comprising from 70 to 90% hydrated lime and from to 30% of a grease composed of substantially eighty-five per cent mineral oil and fifteen per cent soap, said oil having originally a gravity of approximately 24 B., a fiash point of approximately 340 F., a fire point of approximately 395 F., and a Saybolt viscosity of 150 seconds at 100 F., the said grease having a penetration value of from approximately 265 to approximately 290, a melting point of approximately 95 F., and a moisture content of from approximately 1 to 1.5 per cent.

2. A lubricant suitable for applying to bolt stock for lubricating cold-heading dies, said lubricant consisting of from 10 to of a grease composed of a mineral oil and soap, the grease havin a melting point of approximately 195 F., and from to of a fortifying agent for the grease selected from the group consisting of hydrated lime, hydrated lime mixed with graphite, and boraX, said lubricant being capable of forming on the stock when drawn through a reducing die, a thin, hard, tightly adherent film which flakes 01f under the impact of the heading dies.

CHARLES G. CANNEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Elder Dec. 24, 1946

Claims (1)

1. A WIRE DRAWING LUBRICANT COMPRISING FROM 70 TO 90% HYDRATED LIME AND FROM 10 TO 30% OF A GREASE COMPOSED OF SUBSTANTIALLY EIGHTY-FIVE PER CENT MINERAL OIL AND FIFTEEN PER CENT SOAP, SAID OIL HAVING ORIGINALLY A GRAVITY OF APPROXIMATELY 24* BE., A FLASH POINT OF APPROXIMATELY 340*F., A FIRE POINT OF APPROXIMATELY 395*F., AND A SAYBOLT VISCOSITY OF 150 SECONDS AT 100*F., THE SAID GREASE HAVING A PENETRATION VALUE OF FROM APPROXIMATELY 265 TO APPROXIMATELY 290, A MELTING POINT OF APPROXIMATELY 195*F., AND A MOISTURE CONTENT OF FROM APPROXIMATELY 1 TO 1.5 PER CENT.