ITRM930524A1 - LUBRICANTS FOR DRY DRAWING OF WIRES. - Google Patents

Description

DESCRIPTION

accompanying an application for an invention patent

by title:. "Lubricants Der the dry drawing of wires".

The present invention relates to compounds for the dry drawing of dust-free wires, to the processes for their production, in particular to lubricating compounds for the dry drawing of wires characterized as compositions. and dry, bulk free-flowing, non-dusty, non-pulverizable constructions having at least one reproducibly controlled size which form viscous lubricating films either directly or after size reduction.

Basis of the invention Wire drawing? a process used to produce wire from rods by passing by pulling the rod and the wire through one or more? dies to reduce the area of the cross section until a final product of the desired cross section is obtained.

"Wand" is a term used to indicate a non-drawn, hot-rolled piece used in the wire drawing process. Wire is the term used to indicate the product of drawing, that is, a rod that has been reduced cross section area.

The dies used in the wire drawing process must be of sufficient hardness to withstand pressure, heat, and abrasives - t? developed by the wire passing through the die. Most of the dies for wire drawing? made of special alloys such as tungsten carbide or similar hard materials or alternatively, the surfaces of the die, which may be in contact with the moving wire, are coated with abrasion resistant, thermally stable coatings. Direct contact between the surface of the die and the moving surface of the wire must be kept to a minimum, or preferably completely avoided, to maintain the desired surface characteristics of the wire and prevent excessive wear and damage of the die.

Typical dies designed for wire drawing operations consist of 4 zones which can be described as follows: Zone 1, or the approach zone, consists of an angle opening.

circumferential re surrounding the moving wire which allows the lubricant to draw the. wire to enter the die.The angle of the inner surface of the area of. approach, with respect to the moving rod or the wire surface,? typically from 6? at 25 ?. The choice of the angle of the approach zone depends on the size and composition of the wire to be drawn, on the speed? of drawing, by the number of reductions required, and by the lubricant formulation and by the physical form. The lubricant must be in a form that allows it to enter the approach zone together with the thread. Zone 2, or reduction zone,? the point inside the die where the plastic deformation of the rod or wire occurs. It is in zone 2 that the reduction of the cross-sectional area is obtained during drawing. Zone 2? a continuous extension of zone 1, which surrounds the moving wire. The angle of the inner surface of zone 2 with respect to the moving wire determines both the degree of reduction of the cross section and d? a major factor in controlling the thickness of the lubricant film for the drawing of the wire which remains on the surface of the wire as it exits the wire. This residual lubricant? essential when it is necessary to use a certain number of dies in series to make reductions of the straight section in pi? stages. Zone 3? Reported as the support zone. It mainly serves to ensure the final shape of the wire. Zone 4? the pressure relief zone. The pressure developed between the surfaces of the wire and the die can? reach many thousands of pounds per square inch during the drawing operation. It is necessary that this pressure is released at the exit of the die in order to avoid damage to the die. Without a pressure relief zone, shattering of the die could occur.

Dies can be used in combination with a single die holder. These are referred to as pressure dies and are and are designed to increase the pressure on the wire drawing lubricant to force additional lubricant onto the wire surface and thereby increase the thickness of the residual lubricant film.

How ? been noted above,? It is essential that the rod or wire is prevented from coming into contact with the surface of the die during drawing. This ? obtained by maintaining a continuous lubricating film between the surface of the die and the surface of the moving wire. When dry wire drawing lubricants are used, the rod or wire is pulled continuously through a bed of dry wire drawing lubricant contained in a "soap box" or "drawing box" The soap box has an inlet opening and an outlet opening through which the yarn passes. The outlet opening of the soap box? consisting of a first die placed in such a way that the die is below the surface level of the compound for drawing the wire contained in the soap box. Periodic additions of the wire drawing compound are made in the soap box to ensure that its first wire is always submerged in the wire drawing compound.

When using a series of dies for multi-stage reductions, there may be additional soap boxes associated with the specific dies. The purpose of these additional boxes? to provide an additional surface lubricant coating.

The wire that is pulled through the die system travels at high speed. of a few feet per minute (1 foot = about 0.3 m), depending on the die system, the composition of the wire, the reduction of the required cross-sectional area, the capacity? cooling system, and the available lubricant. At these high speeds? ? it is necessary that the surface of the non-drawn rod is roughened so? that the lubricant will adhere? to the surface in quantity? enough and will be? brought into the die. The roughening of the wand can? be done by applying chemical coatings to the rod prior to its introduction into the wire drawing system. The compositions of coating pi? common are based on quicklime, borax, or phosphates. The resulting rough coating is commonly referred to as a "lubricant carrier" coating.

A mechanically descaled wand can? be sufficiently rough without further coating or, if? necessary, can? be made rough cp, an additional mechanical treatment. Lubricant applicators can be used to force lubricant onto the surface of the wand by pressure.

The lubricating compounds for dry drawing wire must be free-flowing in the soap box so that fresh lubricant is exposed to the moving wire. If the drawing compound fails to move freely due to gravity? or mechanical stirring in the soap box, it will be? compact in a dense mass through the auale the moving wire former? a channel. This ? a condition known as "channel formation". Once canal formation occurs, there? a loss of contact between the wire and the dry lubricant and, as a result, the die system? deprived of the lubricant and s? will verify? damage to the wire and to the surface of the die.

When the lubricating compound for the dry drawing of the wires enters the die in the approach zone, it is converted by heat and / or pressure into a film of a consistency similar to that of plastic. If it were converted to a liquid, it would offer, if it would, a little protection against lateral movement of the wire through the area and contact with it. surface of the die. Furthermore, the greater part of the liquid lubricant applied to the wire in this type of drawing system would be lost immediately at the exit of the die and would not be available as a residual lubricant for the protection of other dies in a multiple system. dies.

The composition of the lubricating compounds for dry wire drawing? has been extensively discussed in the patent and technical literature, some examples of which are indicated below in the detailed description. In a broad sense,? dry wire drawing compounds are typically based on a combination of fatty acid soaps, an excess of free or basic fatty acid, and, as required for specific applications, various thickening agents, pressure additives, pigments, charge, and thermal stabilizing agents. The lubricating compounds for the drawing of dry wires pi? commonly used are based on calcium soaps or sodium soaps. A manufacturer of lubricating compounds for dry wire drawing typically offers several hundred different formulations, each designed to meet the technical requirements of specific wire drawing applications.

Historically, lubricating compounds for dry wire drawing have been produced as fine powders to meet the stringent requirements of the wire drawing process. However, these powdered materials are very dusty, causing worker irritation and leading to unclean work areas.

Have several approaches been tried to alleviate dust problems? associated with lubricating compounds for dry wire drawing. These include tableting, extrusion, flaking, beading, and wetting. However, none? complete success status.

The wetting of the compound with a liquid to eliminate the dust? introduces an inactive diluent that often has a harmful effect on one or more? of the properties essential elements of the lubricant, such as lowering the melting point or reducing mass flowability.

The "beading"? a method of manufacturing lubricating compounds for the drawing of dry wires described in Canadian Patent 1006497. Although this patent describes a composition which? "essentially dust-free", it states that "the presence of fine materials in - minor quantities .... can be tolerated or loss of operational efficiency. In practice, these bead compositions are less than completely dust-free as the presence of fine particles would be expected ^ Removal of fine particles by sieving or washing would add costly production steps. Furthermore, the roll-formed beads are not uniform in size in any direction, resulting in separation during shipping and I 'use.

The flaking of lubricating compounds for dry wire drawing by pouring a molten mass of the lubricant onto a cold cylinder? essentially inefficient. The resulting flakes are too large, typically half an inch (12 mm) in diameter, to function efficiently in wire drawing systems. Grinding the flakes to produce smaller particle sizes small 1nvar1 probably leads to the production of a fine dust fraction and dustiness.

The reduction in tablets? an expensive process, and, again, the particle size, typically a quarter of an inch (6 mm) or more in diameter, isn't it? satisfying

The extrusion of dry wire drawing compounds using conventional screw extruders, operated in a conventional manner, such as those used in the preparation of bite plastics or plastic additives? unsuccessfully attempted in the lubricating compound industry for dry wire drawing. While the bits produced were free of dust, the work energy required to form them hardened the bits themselves so that they did not melt or shrink to a useful size in the wire drawing process.

It is completely surprising that the process of the present invention solves all the problems of the previous attempts to prepare lubricating compounds for dry, dust-free, efficient wire drawing, especially since it has been developed. no additional permanent additives were required such as water-soluble binding agents which could interfere with the properties. lubrication or change these properties? of lubricating compounds for dry wire drawing.

Add it to the invention

The present invention relates to a method for the production of priming compounds for the drawing of dry, dust-free wire and soap-compositions for metals having at least one dimension controlled from the point of view of reproducibility. who own all the properties? advantageous of powder lubricants and none of the properties? undesirable dust, such as the production of dust. The process comprises the steps of conglutinating and shaping the compound composition for dry wire drawing under controlled pressure. The stages of conglutination and shaping can be carried out in succession or simultaneously.

The materials used as starting materials in the process are dry wire drawing compounds, usually in powder form, including metallic soaps, basic unreacted compounds, free fatty acids, and, if required for specific applications, quantities ? minors of various auxiliary agents such as bulking agents, pigments, dyes, extreme pressure additives, stabilizers, thickeners, waxes and polymers, esters, ethoxylates and metal wetting agents.

A wide range of temperatures can be used in the forming stage under pressure, with the limitation that it is below the melting point of the metal soap component of the dry wire drawing composition. At least one size of the shaped article formed in the pressure forming stage? uniformly reproducibly.

A wide range of energy of pressure formation can? be used with the condition that it is not greater than the energy required pi? late to reduce the product of the process into smaller particles? small during use by dusting, softening, or melting.

The application pi? preferred for the original products of the invention? in the drawing of wires through stationary or roller dies. As used herein the terms such as "dust free" or "dust free" refer to compound constructions for drawing shaped wire which are essentially free of particulate materials which can generate dust as formed. Quantity Minor dust particles can be produced during the cutting operations to form the construction of desired length or lengths, but these can be easily removed, typically exposing the construction to vacuum during the cutting operation.

Detailed description of the invention Now? A method has been discovered for the production of lubricating compounds for drawing conglutinated and shaped dry powder-free wires, the products of shaped lubricating compounds thus obtained having at least a reproducibly controlled size. The method can? be carried out using a variety? of equipment such as screw extruders, roller extrusion presses, or roller presses. The grinding action that occurs in the production of small pieces in presses for reduction into small pieces, or in stationary dies with pressure of rotating cylinders or rotating dies with pressure of stationary cylinders, efficiently reduces the agglomerates resulting in a compound product for the drawing of dry wires pi? uniform which in turn d? as a result, a coating pi? uniform on the wire.

The dry wire drawing lubricating compounds useful in the present invention have been extensively described in the literature as follows, each of which? incorporated herein for reference. One such publication, an article by Richard Platt entitled "Choosing a Powdered LU? Bricant for Ferrous JUre Drawing" in WTre Technology, May 1989, describes the general composition of a lubricant for dry wire drawing and provides a table owned in relation to the composition to the residual thickness of a film. Another article titled "Lubricaiion of Ferrous Wire" in Ferrous Wire? volume 1, "The Manufacture of Ferrous ire ,." published by the Wire Association International, Inc., discusses various types of lubricants, their proper choice, and some of the terminology - thus, the descriptive terms accepted by the lubricant industry that leave a thick residual film on the wire? "lean", while those that leave a thin film are reported as "rich". The "rich" lubricants have a higher fatty acid content? high of "lean" lubricants. A further classification discussed by Platt divides compounds for dry wire drawing into compounds d? soluble sodium soaps and insoluble calcium soap compounds. A "lean" soap formulation typically contains 30% fatty acid while a "rich" soap formulation typically contains 70% fatty acid. Both of these articles describe that other additives may be present to help maintain stickiness. during the drawing process, to act as lubricants for extreme pressures, to provide anti-corrosive characteristics, and to add color. U.S. Patent No. 29560 * 7 (Franks) discloses calcium soap compositions useful in dry wire drawing compounds. Franks also notes that the combination of calcium soaps with diamine waxes? advantageous. United States Patent No. 4404828 (Blatchford) describes the process of? wire drawing using lubricating powders for wire drawing, classification and composition of powder lubricants for dry wire drawing, the dust problem associated with powder lubricants, and so on. Dry wire drawing lubricating compounds useful with the present invention are those which are based on metal soaps, particularly calcium soaps and sodium soaps as described in the references mentioned above. The procedure described here? Also advantageous in the novel treatment of "spent" wire drawing compounds - that is, those materials which have been eliminated from the drawing system or which have been passed through the die or dies and become separated from the wire. They can be unchanged due to their chemical composition or be modified by exposure to heat, absorption of metals or other forms of contamination. Such materials are often in the form of flakes or flakes, string-like materials or dust. These spent materials can be recovered by vacuum systems, for example, and again subjected to treatment alone or in admixture with virgin wire drawing compound to produce satisfactory shaped constructions of dry wire drawing compounds, often without stages. purification intermediates. The method of the invention comprises the steps of (A) conglutinating the lubricating composition for dry wire drawing and (B) shaping the conglutinated product under controlled pressure to provide a dust-free shaped lubricating product having at least one controlled size in reproducible way, pulverizable by the wire drawing process. Stages A and B can be performed sequentially or simultaneously. ; "Conglutination"? a term used to describe the process of attaching a mass of individual particles together as if they were glued together. The ", agent" of conglutination? a combination of heat and pressure, with or without water present. Self ? present water, can? be the water that remains in the metal soap composition produced during the reaction of the metal hydroxide with the fatty acid or it can be be added to the process, for example, in the pressure forming step. If the water? present it will be? normally present in the range of from about 0.5 to about 10.0 2 by weight of the weight of the finished product. The maximum water present in any given wire drawing compound composition depends on the end use of the wire drawing compound and varies with wire composition, process configuration, and speed. of the thread. Elevated temperatures may be employed to facilitate conglutination and pressure formation of the desired shape and physical strength of the desired product. The elevated temperatures used in the process will be lower than the melting point of the metal soap used in the dry wire drawing lubricant. Preferred temperature range? from - about 50 to about 120? C, pi? preferably 70-90. These elevated temperatures refer to the temperature of the dry wire drawing compound composition as it enters the forming equipment. present in the training equipment. The elevated temperatures of the lubricating composition may be the residual heat from the soap forming step or may be achieved by exposing the composition to elevated temperatures or by providing heat to those portions of the forming apparatus which come into contact with the wire drawing compound. during training. Where the pressure forming apparatus comprises a portion of a continuous process, the residual heat of the soap making is used to advantage. The bits exiting the die plate can be advantageously cooled by passing air through to lower their temperature and minimize adhesion to each other or to the surfaces of the processing equipment. Can these exiting bits also be subjected to a vacuum, close to the bar of the cutting device? to the bar itself that cuts 1 pieces to the desired lengths, to reduce or eliminate the fine particles that can be generated during the cutting or breaking action. The pressure that must be applied to the conglutinated or conglutinated product to form the powder-free, shaped, dry wire drawing compound covers a wide range and determined by the metal soap composition of the dry wire drawing compound, by the strength required of shaped articles to withstand the rigors of shipping and handling and still being useful in wire drawing, by the forming process equipment that is used. It? also influenced by the temperature used and by the presence or absence of water. AND? the physical strength required of the final shaped product which determines how much pressure should be used. For example, bits (or other forms) of dry wire drawing compound produced by the process of the present invention should be strong enough to resist cracking or deterioration to form dust during transportation and handling (generally capable of withstanding pressures of at least 10 pounds per square inch (approx.0.7 kg / cm) but easily powdered when in contact with the moving wire (generally satisfactory if pulverized at a pressure of less than approximately 300 pounds per square inch ( about 21.1 kg / cm). It is essential that these pieces are reduced in size rapidly during the wire drawing operation so that they can enter the approach area of the die where softening and melting begins to form a plastic film Some pieces, especially those with a diameter of less than 1 mm, can enter the approach or and zone are directly in the melt without pulverizing.

While the action of the movement of the thread through the bits in the soap box? the main force that reduces the pieces to dust, can? It would be desirable to add a small amount to the initial start-up of a wire drawing line. of pulverized compound for drawing wires to the soap box to ensure a complete coating of the wire before the pulverization process reaches equilibrium. Another means of getting there? ? the use of lubricant applicators which are well known in the art to crush lubricants and force dust onto the wire.

A particular advantage of the shaped constructions of wire drawing compounds described herein? that they form a "blanket" over the pulverized material in the soap box. The most shaped constructions? large ones rise to the top of the soap box while the pulverized materials remain at the bottom of the soap box surrounding the thread. This covering action suppresses the release of finely pulverized wire drawing compound to the atmosphere. An additional advantage of these shaped constructions? that the coatings deposited on the wire are more? uniforms of those produced using conventional compounds for the drawing of powdered wires, possibly due to the segregation of the powdered material into non-homogeneous layers during transport and handling; the wire evenly coated in turn? pi? easy to handle in post-drawing operations.

The powder-free, shaped wire drawing lubricants produced by the process of the invention can be produced in a wide variety of products. of shapes, such as, for example, cubes, balls, cylinders, pieces, or flakes. However, ? It is essential that at least one dimension be reproducibly controlled and not so large that it is not usable in the wire drawing operation. In general, a large diameter wire can be treated with small or large constructions of shaped wire drawing lubricants produced by the process of the invention, while small diameter wires will normally require larger constructions. small compounds for wire drawing. A typical size for the products of the present invention that can be used successfully in wire drawing? one having a diameter or thickness of about 0.5 to about 10 mm. All other size will be about 5-7 times the checked size, or less.

The indication that lubricant constructions have at least one reproducibly controlled size includes the use of a mixture of two or more. groups of pieces, each group of pieces having variable dimensions of the dimension (or dimensions) controlled in a reproducible way

A favorite shape of the product? a cylindrical piece having a diameter of 2 mm and a length not greater than 10 mm. The realizations more? preferred are pieces having a diameter of 1.6 mm and a length of about 10 mm and pieces having a diameter of 1 mm and a length of about 5 mm.

Here are some representative examples:

Examples A-D

Representative dry wire drawing lubricants were prepared in a stirred reactor at a final temperature of 90 ° C and formed into dust-free chunks in an extrusion barrel. The compositions are shown in the following table I.

The barrel extrusion press used in the experiment included a flat nozzle plate having a plurality of cylinders. of perforations with a diameter of 1 mm and 3 mm in length. A series of two cylinders moves / transversely through the upper openings of each of the perforations every 2-3 seconds. The cylinders were suspended approximately 0.75mm above the top surface of the mouthpiece plates. The lubricating compositions of Examples A to D were fed continuously into the space between the cylinder surface and the nozzle plate. The lubricating composition was converted from essentially powder to continuous filaments extruded through each perforation of the nozzle plate. A crushing blade, which rotates under the mouthpiece plate and adjusted, for the distance from the mouthpiece plate and the speed? of rotation controlled the length of each piece produced. Thus, the extruded filaments, 1 mm in diameter, were cut or broken to a controlled length of about 7 mm on average.

The water reported in Table I is used in the formulation to convert metal oxides into metal hydroxides which in turn react with fatty acids to form soaps. The additives are conventional bulking agents, thickening agents, anti-corrosives, and the like.

Table I.

Composition of soap for dry wire drawing

It was found that the powder-free n-bits compounds for pulverizable dry wire drawing of Examples A to 0 could be pulverized into powder by applying a force of approximately 20 pounds per square inch (psi) (approximately 1.4 kg / cm 2) The bits of Examples A to D were cohesive enough to resist shattering during packing and transportation.

The estimation from the pieces of Examples A and C was carried out on equipment for drawing wires of a size in production. The results are shown in Table II. The "reference" samples were the same lubricating compositions but not in bite form. With the insoluble calcium soap (Example C), 10% by weight of additional water was added in the pressure forming step to produce bits containing about 115% by weight of unreacted water after partial drying.

Table 1 to I I

No.

v

Q

b

Dust production:

for the pieces none none for the abundant reference abundant Examples E-F

Was a test carried out to determine applicability? of the process of reprocessing the "exhausted" material. After a few operations! of wire drawing, the spent lubricant (a sodium, soluble, rich soap) was collected from the floor under the wire drawing machine and from the soap box, taking care to exclude metal particles and non-soap products. The spent material was dusty and had a similar analysis to that of Example A above, except that the fatty acid content was about 77%, the metal oxides about 15%, the additives about 8% , and water less than 1%. This material was again reduced to small pieces on a 1 mm mouthpiece, partly as such (example E) and partly (example F) Mixed with virgin material

rite / 25% - virgin), the virgin material being made up of about 79-81% of fatty acid, about -10-13% of metaIlic oxide, about 4-6-% of additives, and less than 2% of water. Bits prepared from both materials - showed positive lubrication results in an estimate of one hour.

Example 3

A series of estimates were made to determine the strength of the bits produced according to the present invention - the "strength", with reference to the resistance to powder reduction where they were exposed to the pressure between two opposing plates in a machine (an apparatus d? test Instron 4204 Tester) was indicated to estimate the properties? physics of dry materials. The tests were carried out on pieces consisting of various compositions, based on sodium and calcium, rich and lean, with diameters ranging from 0.8 to 6.2 mm and lengths ranging from 3.4 to 13.3 mm. 1 results in all? cases showed that? bits were resistant to powder reduction at pressures below about 17 oses (1.19 kg / cm) and about 292 psi (20.44 kg / cm).

Claims (2)

CLAIMS 1. Dust-free, shaped, dry-wire drawing lubricants which consist of metallic soaps, have at least one reproducibly controlled size, and are pulverizable by wire drawing processes into viscous lubricating films. . 2. Shaped lubricant as in claim 1 which? in the form of a cylindrical sump 3. Shaped lubricant as in claim 2 wherein the chip resists shattering at a hole of about 10 psi (about 0.7 kg / cm). 4. Shaped lubricant as in claim 2 wherein the chip easily reduces to powder at a force of between about 10 psi (0.7 kg / cm) and about 300 psi (-21 kg / cm). - 5.-Shaped lubricant as in claim 2 wherein the piece has a diameter of 1 to 2 mm and an average length of 5 to 10 mm. 6. A shaped lubricant as in claim 1 wherein the lubricant contains a sodium or calcium soap. 7.-Method for providing a thread with a uniform lubricating coating during the drawing of the thread which includes the operation of pulling said thread, before through a bed containing the lubricant for drawing d? shaped dry wires of claim 1. 8. Coated wire according to claim 7. 9. A method as claimed in claim 7 wherein - some amount - of the lubricant in the bed? in pulverized form. 10. Process for the production of compounds for the drawing of dry, powder-free and shaped wires, which are made up of metal soaps, have at least a reproducibly controlled dimension, and can be pulverized by means of wire drawing procedures such as ? to form viscous lubricating films, which method comprises conglutinating and shaping the compound composition for the dry wire under controlled pressure. 11. A process as claimed in claim 10 wherein the composition contains a sodium or calcium capon. 12. Process of claim 10 conducted in the presence of water. 13. Process as claimed in claim 10 wherein the composition? conglutinated at a temperature of about 50? C to about 120? C. 14. Process of claim 10 wherein a roller extractor press is used to carry out the shaping. 15. Process as claimed in claim 10 Where the composition? Consisting of compounds for the drawing of exhausted wires.