JPH06166883A - Dry drawing lubricant - Google Patents

Abstract

Shaped, dust-free dry wire drawing compound lubricants having at least one reproducibly controlled dimension and methods for their preparation comprising the steps of conglutinating and pressure forming the lubricant composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is a dust-free product.
free) dry wire drawing compounds and processes for their preparation, especially dry free flowing non-powdered non-dusty compositions,
And a reproducible, controlled dimension of at least 1 to form a viscous lubricious film, either directly or after reduction of cross-sectional area.
The present invention relates to a dry drawing composition lubricant characterized by having a structure having two.

[0002]

BACKGROUND OF THE INVENTION Wire drawing is used to produce wire by drawing bar and wire through one or more dies to reduce the cross-sectional area to obtain a final product having the desired cross-sectional area. It is a process that is performed. The term "bar material" is a term used for a hot-rolled non-drawn work material used in a drawing process. "Wire rod" is a term for a product produced by drawing, that is, a rod rod having a reduced cross-sectional area.

The die used in the wire drawing process must have sufficient hardness to withstand the pressure, heat and wear caused by the wire passing through the die. Most wire drawing dies are made of special alloys such as tungsten carbide or similar hard materials, or instead their surface, which may come in contact with running wire, is thermally stable and wear resistant. Covered by a coating. Direct contact between the die surface and the running wire surface should be kept to a minimum to maintain the desired surface properties of the wire and avoid excessive die wear and damage, or no contact at all is preferred. .

A typical die designed for drawing operations consists of four bands which can be described as follows. Band 1 (the inlet channel) consists of a circumferential angular opening that surrounds the running wire which allows the draw lubricant to enter the die. The angle of the inner surface of the inflow zone is typically 6 to 25 degrees with respect to the surface of the running bar or wire. The choice of inlet channel angle depends on the size and composition of the wire being drawn, the drawing speed, the number of reductions required, and the composition and physical shape of the lubricant. The lubricant must have a shape that allows it to enter the inlet channel along with the wire. Band 2 (reduction band) is a place in the die where plastic deformation of the rod or wire occurs. It is in this zone 2 that a reduction in cross-sectional area occurs during drawing. Band 2 is a continuous extension of band 1 and surrounds the running wire. The angle of the inner surface of the strip 2 with respect to the running wire determines the extent of cross-sectional area reduction and is a major factor in controlling the thickness of the draw lubricant film remaining on the wire surface when exiting the die. This residual lubricant is indispensable when many dies are continuously used to perform multi-step cross-sectional area reduction. The band 3 is called a bearing band. This mainly serves to ensure the final shape of the wire. Band 4 is a pressure relief band. The pressure created between the wire and the die surface during the drawing operation can reach thousands of pounds per inch ² . This pressure must be released at the die exit in a manner that does not damage the die. Without a pressure relief zone, the die could crack.

The dice can be used in combination with one die stand. These are called pressure dies, and are designed to increase the pressure applied to the drawing lubricant in order to attach the additional lubricant to the surface of the wire and increase the thickness of the residual lubricant film.

As mentioned above, it is important to prevent the bar or wire from contacting the die surface during drawing.
This is accomplished by maintaining a continuous film of lubricant between the die surface and the running wire surface. When a dry wire drawing lubricant is used, the bar or wire is continuously drawn through a bed of dry wire drawing lubricant contained in a "soap box" or "die box". Wire passes through the soap box 1
It has one inlet and one outlet. The outlet of the soap box consists of a first die positioned below the surface level of the wire drawing compound contained within the soap box. In order to ensure that the first die is always submerged in the wire drawing composition, the wire drawing composition is added to the soap box on a regular basis.

When continuous dies are used for multi-step reduction, additional soap boxes may be associated with a particular die. The purpose of these additional soap boxes is to provide the wire with an additional surface lubricant coating if necessary.

The wire rod drawn through the die system is
Run at speeds of several feet to thousands of feet per minute depending on the die system, wire composition, degree of cross-sectional area reduction required, cooling capacity, and available lubricants. At such high speeds, it is necessary to roughen the undrawn bar surface so that a sufficient amount of lubricant can be deposited on the surface and carried into the die. Roughening the bar may be accomplished by applying a chemical coating prior to its introduction into the drawing system. The most common coating compositions are those based on lime, borax, or phosphate. The resulting rough coating is commonly referred to as a "lubricant carrier" coating.

Mechanically descaled bars are sufficiently rough without further coating, and if necessary can be roughened by the addition of mechanical treatment.
A lubricant applicator can be used to apply the lubricant to the bar by pressure.

The dry wire drawing composition lubricant must flow freely in the soap box in order to expose the new lubricant to the running wire. If the wire drawing composition cannot move freely due to gravity or mechanical agitation in a soap box, the wire drawing composition solidifies into a dense mass, forming wires and channels running through the dense mass. Will be done. This is a condition known as "tunnel flaw".
Once a tunnel flaw occurs, the contact between the wire and the dry lubricant is lost, resulting in a lack of lubricant in the die system and damage to the wire and die surface.

As the dry wire drawing compound lubricant enters the die in the inlet zone, it is transformed by heat and / or pressure into a film of plastic-like consistency. If it turns into a liquid, it provides little, if any, protection to the wire that moves laterally through it and contacts the die surface. Furthermore, most of the liquid lubricant applied to the wire in this type of drawing system is lost immediately upon exiting the die, leaving residual lubricant to protect the other dies in a multi-die system. Can not be used as.

The composition of dry wire drawing compound lubricants has been extensively discussed in the patent and technical literature, some examples of which are described in detail below. In a broad sense, dry wire drawing formulations typically include fatty acid soaps, overbased or free fatty acids, and the various thickeners, pressure additives, pigments, fillers, thermal additives required for a particular application. Based on a combination of stabilizers. The most commonly used dry wire drawing composition lubricants are based on calcium or sodium soaps. Manufacturers of dry draw compound lubricants typically provide hundreds of different formulas, each of which is designed to meet the technical requirements of a particular wire drawing application.

[0013]

Dry wire drawing compound lubricants have historically been produced as fine powders to meet the stringent requirements of the wire drawing process. However, these powdered materials are very dusty, which gives workers an irritating and unsanitary working environment.

Various approaches have been tried to alleviate the dust problems associated with dry wire drawing compound lubricants.
These include tableting, extrusion, flaking, beading, wetting. But none of them have reached full success.

Infiltrating the formulation with a liquid to control dust involves introducing an inert diluent which often has multiple deleterious effects on important lubricant properties, such as lower melting points or reduced free-flowing properties. Become.

"Beading" refers to Canadian Patent No. 100649
A method of making the dry wire drawing composition lubricant disclosed in No. 7. Although this patent discloses a "substantially dust-free" composition, it states that "the presence of a small amount of fines ... is acceptable without loss of working efficiency". In practice, these beaded compositions are by no means totally dust-free, as would be expected from the presence of fine particles. Removal of fines by screening or washing would add an expensive manufacturing step. Furthermore, the beads formed by rolling are not homogeneous in size in any direction, resulting in separation during shipping and use.

The molten mass of lubricant is cast on a chill roll (cas
flaking the dry wire drawing formulation lubricant is essentially ineffective. The resulting flakes are too large--typically one-half inch diameter (12 mm)-to effectively function in a drawing system. Grinding the flakes into smaller particles inevitably results in finely divided parts and dust.

Tableting is an expensive process, and the particle size--typically greater than a quarter inch (6 mm) in diameter--is unsatisfactory.

In the dry wire drawing compound industry it is customary to operate a conventional screw extruder, such as that used in making pelletized plastics or plastic additives, in a conventional manner to extrude the dry wire drawing compound. Have been tried, but still unsuccessful. Although the pellets produced are dust free, the work energy required to form them does not melt or reduce to a convenient size during the drawing process to harden the pellets. is there.

[0020]

SUMMARY OF THE INVENTION It is, in particular, dry wire drawing that the method of the present invention solves all the problems of the prior art attempts to produce effective, dust-free, dry wire drawing compound lubricants. This is entirely surprising as it does not require permanent additional additives such as water-soluble binders that interfere with or alter the lubricating properties of the formulation lubricant.

The present invention has all the advantageous properties of dust free dry wire drawing compound lubricants and powder lubricants, and has reproducible, controlled dimensions with no undesirable powder properties such as dust generation. The present invention relates to a method for producing a metal soap composition having at least one of The method comprises the steps of coalescing and shaping a dry wire drawing compounding composition under controlled pressure. The coalescing and shaping steps can be performed sequentially or simultaneously.

[0022]

The materials used as raw materials in the process are usually powder-form dry wire drawing compounds, unreacted basic compounds, free fatty acids, as well as special needs for metal soaps. Various adjuvants such as small amounts of fillers, pigments, dyes, extreme pressure additives, stabilizers, thickeners, waxes and polymers, esters, ethoxylates, metal wetting agents and the like.

A wide range of temperatures can be used in the pressure forming step, with the restriction that it is below the melting point of the metal soap component of the dry wire drawing formulation. At least one of the dimensions of the shaped article formed by the pressure forming step has reproducible uniformity. A wide range of forming pressure energies may be used, provided that it is not greater than required to reduce the products of the process to smaller particles by milling, softening or melting during subsequent use.

The most preferred use of the novel products of this invention is in wire drawing through fixed or roller dies. As used herein, the terms "dust-free" or "non-dust" refer to a shaped wire drawing formulation composition as formed and substantially free of dusty particulates. A small amount of dust particles may occur during the cutting operation to form the desired length of the structure, but these are easily removed by exposing the structure to reduced pressure, especially during the cutting operation. be able to.

[0025]

DETAILED DESCRIPTION OF THE INVENTION A method of making a coalesced and shaped dust free dry wire drawing lubricant formulation has been discovered, the resulting shaped lubricant formulation product having reproducible and controlled dimensions. Has at least one. This method
It can be carried out using various devices such as a screw extruder, a roller extruder, or a roller extruder.
The crushing action that occurs in the pellet molding machine in pellet production, whether it is a fixed die with rotating roller pressure or a rotating die with fixed roller pressure, effectively reduces agglomerates and produces a more homogeneous drawing compounded product. Occurs, which in turn will result in a more uniform coating on the wire.

Dry wire drawing lubricant formulations useful in the present invention include:
It is widely described in the following documents, which are incorporated herein by reference. One such publication is "Choosing a by Richard Platt of Wire Technology, May 1989.
Powdered Lubricant for Ferrous Wire Drawing "discusses the general composition of dry wire drawing lubricants and provides a table of properties relating that composition to residual film thickness.
Ferr issued by ociation International, Inc.,
The document entitled "Lubrication of Ferrous Wire" in "The Manufacture of Ferrous Wire," Vol.
It describes various types of lubricants, their proper selection, and some scholarly terminology--hence the industry.
We accept the term "lean" for lubricants that leave a thick residual film on the wire, while those that leave a thin film are called "rich". A "rich" lubricant has a higher fatty acid content than a "lean" lubricant. Pl
A further class discussed by att divides dry wire drawing formulations into soluble sodium soap formulations and insoluble calcium soap formulations. "Lean" soap formulations are typically 3
While containing 0% fatty acids, "rich" soap formulations typically contain 70% fatty acids. Both of these references suggest that other additives may be present to help maintain viscosity during the drawing process, to act as an extreme pressure lubricant, to provide corrosion resistance properties, and to color. Disclosure. Franks U.S. Pat. No. 2,956,017 discloses calcium soap compositions useful in dry wire drawing formulations. Franks further notes that the combination of calcium soap and diamide wax is advantageous. Blatchford U.S. Pat. No. 4,404,828 discusses wire drawing processes utilizing dry wire drawing lubricant powders, classification and composition of dry wire drawing powder lubricants, dust problems associated with powder lubricants, and the like.

Dry wire drawing lubricant formulations useful in the present invention are based on metal soaps, especially the calcium and sodium soaps described in the references cited above. The method described herein is also advantageous for reworking "spent" wire drawing compounds-that is, materials that the die system did not accept or passed through the die and separated from the wire. They have the same chemical composition or heat exposure,
It can be altered by metal pickups or other forms of contamination. Such materials are often in the form of scales or flakes, cords, or powders. These used materials can be recovered by, for example, a vacuum system and used alone or in a new wire drawing compound, often without the need for intermediate purification steps, to produce a dry wire drawing compound structure of satisfactory shape. It can be blended with objects and reprocessed.

The process of the present invention comprises (A) the step of coalescing the dry wire drawing lubricant composition and (B) the step of shaping the coalesced product under controlled pressure and is reproducible. Provided is a dust-free shaped lubricant product which has at least one controlled dimension and can be finely pulverized by a drawing process. Steps A and B can be performed sequentially or simultaneously.

"Coalescence" is a term used to describe the process of laminating individual particle masses together as if they were glued together. A coalescing "agent" is a combination of heat and pressure in the presence or absence of water. If water is present, it may be the water remaining in the metal soap composition generated during the reaction of the metal hydroxide with the fatty acid, or, for example, adding water during the pressure forming step. You can also If water is present, it is usually present in the range of about 0.5 to about 10.0 wt% of the final product weight. The maximum amount of water present in a given composition of the wire drawing formulation depends on the end use of the wire drawing formulation and will vary with wire composition, process configuration, wire speed.

High temperatures can be used to promote coalescence and pressure formation to obtain the desired shape and physical strength of the final product. The elevated temperature used in this step is below the melting point of the metal soaps used in dry wire drawing lubricants.
Preferred temperatures range from about 50 to about 120 ° C., 7
Most preferred is 0 to 90 ° C. These elevated temperatures refer to the temperature at which the dry wire drawing composition enters the forming apparatus or is present in the forming apparatus. The elevated temperature of the lubricant composition may be residual heat from the soap forming step, or heat may be applied to parts of the forming equipment that come into contact with the dry wire drawing formulation by exposing the composition to elevated temperatures or during the forming step. May be added by supplying. If the pressure-forming device consists of part of a continuous process, the residual heat of soap production is effectively used. Advantageously, the pellets emerging from the die plate are cooled to minimize sticking to each other or to the surface of the process equipment by passing air between them to reduce their temperature. Also, depressurize these emerging pellets at or near a cutter bar that cuts the pellets to the desired length to reduce or remove fine particles that may occur during the cutting or breaking operations. Can be exposed to.

The pressure exerted on the product being coalesced or being coalesced to form a shaped dust-free dry wire drawing composition is extensive, and the metal soap composition of the dry wire drawing composition, It is determined by the strength required for a shaped object effective in drawing and being capable of withstanding the rigors of transportation and handling, and the process forming equipment used. It also depends on the temperature used and the presence or absence of water. It is the physical strength required of the final shaped product that determines how much pressure will be used. For example, pellets (or other structures) of the dry wire drawing compound produced by the method of the present invention.
When the enough to resist crushing or decomposed into powder during shipping and handling strong enough (generally capable of withstanding a pressure of at least about 10 pounds / inch ²⁾ it is in contact with the wire traveling Is easily pulverized (about 30
It is generally satisfactory if it can be milled at pressures below 0 pounds per inch ^2. ) It is important that the size of such pellets decrease rapidly during the drawing operation so that they can enter the inflow zone of the die where softening and melting of the plastic film begins. Some pellets, especially those with a diameter of less than 1 mm, can enter the inflow zone without being comminuted or go directly to the melt.

While the action of the wire running through the pellets in the soap box is the main force to pulverize the pellets,
It is desirable to add a small amount of comminuted wire drawing compound to the soap box at start-up of the wire drawing line to ensure complete coverage of the wire before the grinding process reaches equilibrium. Other methods of accomplishing this include the use of a lubricant applicator, which is well known in the art for grinding lubricant and applying powder onto the wire.

A particular advantage of the geometry of the wire drawing formulations described herein is that they form a "blanket" for the ground material in the soap box. Large shaped structures rise above the soap box, while finely ground material surrounds the remaining wire below the soap box. This blanketing action inhibits the release of the finely ground wire drawing compound to the atmosphere. A further advantage of these shaped structures is that the coating deposited on the wire is produced using conventional powder wire drawing formulations, presumably due to segregation of the powder material into a non-homogeneous layer during transport and handling. It means that it is more homogenous than the one that has been applied, and that the wire, which has been coated in turn to be more homogeneous, is easier to work after the drawing operation.

The shaped non-dust wire drawing lubricant produced by the method of the present invention can be produced in various shapes such as cubes, spheres, cylinders, pellets and flakes. However, it is important that at least one dimension be reproducibly controlled and not too large to be used in the wire drawing operation. In general, larger diameter wire can be processed with larger or smaller structured wire drawing lubricants produced by the method of the present invention, while smaller diameter wire usually requires a smaller structured wire drawing compound. And Typical sizes of the products of the invention that can be successfully used in wire drawing are those having a diameter or thickness of about 0.5 to about 10 mm. All other dimensions are approximately 5 to 7 times the regulated dimensions or less.

The indication that the lubricant structure has at least one reproducibly controlled dimension is a blend of two or more sets of pellets, each set having different reproducibly controlled dimensions. The use of things is included.

The preferred shape of the product is a cylindrical pellet having a diameter of 2 mm and a length of 10 mm or less. Most preferred 2
One specific example is a pellet having a diameter of 1.6 mm and a length of about 10 mm and a pellet having a diameter of 1 mm and a length of about 5 mm. Some of the representative examples are as follows.

[0037]

EXAMPLES Examples AD Representative dry drawing lubricants were prepared in a stirred reactor at a final temperature of 90 ° C and molded into non-dust pellets on a roller extruder. The composition is as shown in Table 1 below. The roller extruder used in the experiment has a diameter of 1 m.
It consisted of a flat die plate with multiple perforations of m length 3 mm. Two series of rollers crossed over each perforation opening every 2-3 seconds. The roller was suspended about 0.75 mm above the surface of the die plate. The lubricant compositions of Examples A to D were continuously fed into the space between the roller surface and the die plate. The lubricant composition was converted from substantial powder to a continuous extruded strand through each die plate perforation. A crusher blade rotating below the die plate and adjusting the distance from the die plate and the speed of rotation controlled the length of each resulting pellet. Thus an average of about 7 mm of extruded strands with a diameter of 1 mm
Cut or chopped to a controlled length of mm. The water listed in Table 1 was blended to convert the metal oxides to metal hydroxides, which in turn replaced the metal hydroxides with fatty acids to form soaps. Additives were conventional fillers, thickeners, rust inhibitors and the like.

[0038]

[Table 1] Table 1 Dry wire drawing soap composition Soluble sodium Insoluble calcium soap (wt%) Soap (wt%) Rich lean Rich lean Example A ABCD fatty acid 72 49 58 32 metal oxide 9 5.5 30 50 50 additive 13 39.5 2 3 Water 6 6 10 15

The pelletized, non-dusting, millable, dry wire drawing formulations of Examples A to D were prepared at approximately 20 pounds per inch ^2.
It has been found that a powder can be comminuted by applying a force of (psi). The pellets of Examples A to D had sufficient cohesive strength to withstand breakage during packaging and shipping. Evaluation of the pellets of Examples A and C was performed on a production size wire drawing machine. The results are shown in Table 2. The "control" had the same lubricant composition but was not in pellet form. For the insoluble calcium soap (Example C), an additional 10% by weight of water was added during the pressure forming stage to produce pellets containing approximately 5% by weight unreacted water after partial drying.

[0040]

[Table 2]

Tests were conducted to determine the feasibility of applying the Examples EF processes to reworking "spent" materials. After some drawing work, take care to exclude metal particles and non-soap products, and remove the used lubricant (rich, soluble, sodium soap) from the floor below the drawing equipment and the soap box. It was collected.
The used material is dusty, the fatty acid content is about 77%,
The analysis was similar to that of Example A, except that the metal oxide was about 15%, the additive was about 8%, and the water was less than 1%. Using this material with a 1 mm die, some (Example E) as is, some (Example F) about 79-8
1% fatty acid, about 10-13% metal oxide, about 4-6
% Additive, mixed with new material containing less than 2% water (75% used / 25% new) and pelletized again. In a one hour evaluation test, pellets made from these materials both showed positive results as lubricants.

Example G A series of evaluation tests were performed to determine the strength of pellets produced according to the present invention. "Strength" is a machine designed to evaluate the physical properties of dry matter (Instron 4204 Tes
ter) refers to the force that can withstand pulverization into powder when exposed to the pressure between facing platens. The test is
0.8-6.2 mm diameter made from various compositions based on rich and lean, sodium and calcium
And pellets ranging in length from 3.4 to 13.3 mm. The results show that in all cases, the pellets withstand pulverization at pressures less than about 17 psi (1.2 Kg / cm ² ), from about 17 psi to about 292 ps.
At pressures between i (20.5 Kg / cm ² ) the pellets were shown to be easily comminuted.

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Claims (15)

[Claims] 1. A dry dust-free modeling dry drawing lubricant comprising metal soap, having at least one reproducible and controlled dimension, which can be finely ground into a viscous lubricating film by a drawing process. 2. The modeling lubricant according to claim 1, which is in the form of a cylindrical pellet. 3. Pellets of about 0.7 kg / cm ² (10 p
The shaped lubricant of claim 2 which resists the failure of force of si). 4. Pellets of about 0.7 to 21 kg / cm
The shaped lubricant of claim 2 which is easily milled with a force of between ² (10 and 300 psi). 5. The shaped lubricant according to claim 2, wherein the pellets have a diameter of 1 to 2 mm and an average length of 5 to 10 mm. 6. The modeling lubricant according to claim 1, which contains sodium or calcium soap. 7. A uniform coating of lubricant on the wire during wire drawing comprising continuously drawing the wire through a bed containing a shaped dry wire drawing lubricant according to claim 1 prior to drawing. how to. 8. The coated wire rod according to claim 7. 9. The method of claim 7 wherein some of the lubricant in the bed is in finely divided form. 10. A dry drawing lubricant free of dust, which is made of metal soap, has at least one reproducible and controlled dimension, and can be pulverized into a viscous lubricating film by a drawing process. A method of manufacturing, the method comprising coalescing and shaping a dry wire drawing composition under controlled pressure. 11. The method of claim 10 wherein the composition comprises sodium or calcium soap. 12. The method according to claim 10, which is carried out in the presence of water. 13. The method of claim 10, wherein the composition is coalesced at a temperature of about 50 to about 120.degree. 14. The method of claim 10, wherein a roller extruder is used to perform the shaping. 15. The method of claim 10 wherein the composition comprises a used wire drawing formulation.