JP2015189952A - Steel wire material having lubrication coating excellent in corrosion resistance and processability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel wire material having a lubricant coating capable of achieving both of processability such as wire drawability, spike property, ball ironing properties and decladding properties and corrosion resistance such as long-term rush preventive properties.SOLUTION: There is provided a steel wire material containing water-soluble silicate and water-soluble tungstate with a mass ratio of water-soluble silicate/water-soluble tungstate in a range of 0.7 to 10 and having a lubrication coating without phosphorous on a surface.

Description

  The present invention relates to a steel wire having a lubricating film containing no phosphorus on its surface.

  In plastic processing of steel wires and steel wires, friction generated when metal surfaces (especially dies and workpieces) rub against each other violently increases processing energy, generates heat, and causes seizure. Various targeted lubricants have been used. Oil and soap have been used for a long time as lubricants, and by supplying them to the friction surface, the frictional force has been reduced as a fluid lubrication film, but plasticity that slides under high surface pressure with large heat generation due to surface area expansion In processing, seizure phenomenon is likely to occur due to lack of lubricity or running out of the lubricating film. For this reason, borate films, phosphate crystal films, etc. that have sufficient film strength and that are less likely to cause lubrication film breakage due to being present at the interface between the die and the workpiece even under high surface pressure, and avoid direct contact between metals A technique of previously coating a metal material surface with a solid film such as an inorganic film has been generalized. In particular, a composite film composed of a zinc phosphate film and a soap layer (hereinafter sometimes referred to as a chemical conversion film) has high processability and corrosion resistance and is widely used.

  On the other hand, in recent years, the processing energy has been further reduced, the degree of processing has been increased, difficult-to-process materials can be handled, and the environmental protection of the coating process (for example, phosphating has caused a large amount of industrial waste such as sludge. There is a problem in terms of maintenance), and immersion of phosphorus such as bolts (if phosphorus of the coating component remains after header processing of high-strength bolts, phosphorus enters the steel during heat treatment and causes brittle fracture). The demands are increasing rapidly in various fields, and while considering environmental protection for these demands, solid coatings having high lubricity are being developed. This technique is to form a film having high lubricity by a simple process of applying a water-based plastic processing lubricant to the surface of a workpiece and drying it.

  Patent Document 1 discloses a composition in which (A) a water-soluble inorganic salt and (B) wax are dissolved or dispersed in water, and the solid content weight ratio (B) / (A) is in the range of 0.3 to 1.5. An aqueous lubricating film treating agent for plastic working of metal materials and a method for forming the film are disclosed.

  Patent Document 2 discloses an aqueous lubricant film treatment agent containing an alkali metal borate (A), wherein the alkali metal borate (A) contains lithium borate, and the alkali metal borate (A) contains all alkali metals. The molar ratio of lithium to 0.1 to 1.0 and the molar ratio (B / M) of boric acid B and alkali metal M of the alkali metal borate (A) to 1.5 to 4 0.0, a water-based lubricating film treating agent for plastic working of metal materials and a method for forming the film are disclosed. This technique is said to be able to form a film having not only workability but also high corrosion resistance by suppressing the crystallization of the film that occurs when the film absorbs moisture.

  Patent Document 3 contains an A component: an inorganic solid lubricant, a B component: a wax, and a C component: a water-soluble inorganic metal salt, and a solid content mass ratio between the A component and the B component (A component / B component). ) Is 0.1 to 5, and the solid content mass ratio of the C component to the total amount of the A component, the B component, and the C component (C component / (A component + B component + C component)) is 1 to 30%. A water-soluble lubricant for non-phosphorous plastic working is disclosed. This technique is a lubricant that does not contain phosphorus, and is said to be able to realize corrosion resistance equivalent to that of a chemical conversion coating.

  Patent Document 4 contains a water-soluble inorganic salt (A), one or more lubricants (B) selected from molybdenum disulfide and graphite, and a wax (C), and these are dissolved in water or Aqueous lubrication in which (B) / (A) is 1.0 to 5.0 in terms of solids weight ratio and (C) / (A) is 0.1 to 1.0 in terms of solids weight ratio. A film treatment agent and a method for forming the film are disclosed. This technology is said to be able to realize high workability equivalent to that of a chemical conversion treatment film by blending molybdenum disulfide or graphite with a conventional water-based lubricating film treatment agent.

  Patent Document 5 discloses silicate (A), polycarboxylate (B), water-compatible polymer and / or water-compatible organic lamellar structure (C), molybdate and / or tungstate. (D) and the film formation agent whose mass ratio of each said component is a predetermined | prescribed ratio is disclosed.

  As described in Patent Documents 1 to 5, the water-soluble inorganic salt is an essential component in the solid film of the aqueous lubricant film treating agent. The reason is that a lubricating film composed of a water-soluble inorganic salt has a sufficient film strength, and as described above, it is difficult to cause the lubricating film to break by intervening at the interface between the die and the workpiece even under high surface pressure. This is because direct contact can be avoided. Therefore, in the case of a water-based lubricating film treatment agent, a good lubricating state can be maintained during plastic processing by combining a solid film made of a water-soluble inorganic salt or a water-soluble resin with an appropriate lubricant capable of reducing the friction coefficient.

  The film formation mechanism of the water-based lubricating film composed of water-soluble components will be described. The water-soluble inorganic salt of the water-soluble component is in a state of being dissolved in water in the lubricant treatment liquid. When the lubricant is applied to the surface of the metal material and dried, the solvent water evaporates to form a lubricating film. At that time, the water-soluble inorganic salt is deposited as a solid on the surface of the metal material to form a solid film. The solid coating formed in this way has a coating strength that can withstand plastic processing, and exhibits good lubricity during plastic processing by incorporating an appropriate lubricant that reduces the friction coefficient.

International Publication No. 02/012420 JP 2011-246684 A JP 2013-209625 A International Publication No. 02/012419 JP 2002-363593 A

  However, the lubricating films of Patent Documents 1 to 5 are significantly inferior in long-term rust prevention for 2 months or more as compared with the chemical conversion film, and cannot be increased to a practical level. This is because the main component of the film is a water-soluble component, so that moisture in the atmosphere can be easily absorbed or permeated, and the steel material can easily come into contact with moisture. In Patent Document 2, although corrosion resistance is improved by suppressing crystallization of the film due to moisture absorption, moisture absorption itself is not suppressed, and sufficient corrosion resistance is not obtained. Moreover, it is described that the water-based lubricating film described in Patent Document 3 exhibited a corrosion resistance equivalent to or higher than that of the chemical conversion coating film in a corrosion resistance test in a laboratory in which rusting was accelerated using a thermo-hygrostat. However, the actual environment in which the lubricant film is used is usually in a state where dust, dust, and pickling chemical mist can adhere, and in such a harsh environment, the corrosion resistance is better than the chemical conversion film. The actual situation is inferior. As described above, there has been no water-based lubricating film that does not contain phosphorus that has a rust prevention property equal to or higher than that of the chemical conversion film.

  Examples of water-soluble inorganic salts that can provide relatively high corrosion resistance include alkali metal salts of silicates (hereinafter sometimes referred to as silicates), alkali metal salts of tungstates and / or ammonium salts (hereinafter referred to as May be described as tungstate). These water-soluble inorganic salts are also described in Patent Document 1, Patent Document 4 and Patent Document 5. However, they also have a practically inferior corrosion resistance compared to the chemical conversion coating.

  The water-soluble silicate has a property that it hardly permeates moisture in the water-soluble inorganic salt and has very high adhesion to the material. Because of this property, it is a material that can exhibit relatively high corrosion resistance, although not as much as the chemical conversion coating. This is because the water-soluble silicate is crosslinked and forms a network structure in the process of forming a film in which water as a solvent of the lubricant volatilizes. However, because of this network structure, the water-soluble silicate film is too brittle as a lubricating film. For this reason, when a base material is processed, a film | membrane may crack and it may not fully follow. In addition, due to the network structure, the adhesiveness is too high, film removal failure may occur, and various problems may be caused in subsequent processes. For example, in the case where plating is performed in a subsequent process, not only does the film component enter and contaminates the plating solution, but also causes defective plating in the portion where the film component remains.

  Further, water-soluble tungstate hardly absorbs moisture from the outside air when a film is formed. This is because when the water-soluble tungstate forms a film, it forms particulate crystals. Furthermore, water-soluble tungstate has the property of forming a passive film having a self-repairing function on the surface of the steel material, and it can be expected to form a highly corrosion-resistant film by using it as a film component. Moreover, since water solubility itself is high, it can be easily removed with an aqueous solution. However, since the water-soluble tungstate is crystalline, it has poor adhesion to the material and cannot form a uniform film, so that the expected corrosion resistance and workability cannot be obtained. For example, the adhesion and uniformity of the film can be improved by adding a synthetic resin component to the lubricant, but the corrosion resistance is still inferior to that of the chemical conversion film.

  Moreover, the aqueous | water-based lubricating film processing agent containing the water-soluble inorganic salt published in patent documents 1-3 was inferior in processability compared with the chemical conversion treatment film in common. This is particularly noticeable in severe processing where the surface area expansion ratio is several tens of times (hereinafter sometimes referred to as “strong processing”), such as insufficient deformation of the material, reduction in mold life, and seizure. Occur.

  By containing molybdenum disulfide and graphite, the water-based lubricating film treating agent described in Patent Document 4 can obtain workability equivalent to or better than that of the chemical conversion film even during strong working. However, when these components are blended, the color of the lubricating liquid becomes black, and the apparatus, its surroundings and workers are significantly contaminated. Molybdenum disulfide and graphite are liable to settle, and over time, they may harden at the bottom of the treatment tank and become difficult to redisperse, making stable operation difficult. Further, these two components are factors that greatly reduce the corrosion resistance, and the corrosion resistance is inferior to that of the lubricating film of Patent Documents 1 to 3 as well as the chemical conversion coating.

  In Patent Document 5, a coating material containing silicate (A) as a main component and containing too much corrosion-resistant agent (D) or the like has seizure when the extrusion load is high. Since it is inferior, stable work becomes difficult, and long-term rust prevention is not sufficient.

  Thus, a water-based lubricating film could not form a film having high corrosion resistance over a long period of about two months or more and workability at the time of strong processing, which is comparable to a chemical conversion film even in a practical environment. Further, when the silicate is contained in the water-based lubricating film treating agent, defective film removal becomes a problem.

  Therefore, the present invention is to provide a steel wire having a lubricating film capable of satisfying both workability such as wire drawability, spike property, ball ironing property, film removal property and corrosion resistance such as long-term rust prevention property. It was raised as an issue.

  As a result of intensive studies to solve the above problems, the present inventors have determined a specific ratio of silicate and tungstate, that is, a mass ratio of water-soluble tungstate / water-soluble silicate. In order to complete the present invention, it was found that by forming a composite lubricating film with a ratio, high corrosion resistance and workability that could never be achieved with these components alone, and sufficient adhesion and film removal properties were obtained. It came.

  In order to solve the above-mentioned problems, the present invention is configured as follows.

  The steel wire material of the present invention contains a water-soluble silicate and a water-soluble tungstate, and the mass ratio of the water-soluble tungstate / water-soluble silicate is in the range of 0.7 to 10 and does not contain phosphorus. It has a gist in that it has a lubricating film on its surface.

  The lubricating film is formed using a composition in which a water-soluble silicate and a water-soluble tungstate are mixed so that the mass ratio of water-soluble tungstate / water-soluble silicate is in the range of 0.7 to 10. It is preferable that

  The lubricating film contains a resin, and the mass ratio of resin / (water-soluble silicate + water-soluble tungstate) is preferably 0.01 to 1.5.

  The resin is preferably at least one selected from vinyl resins, acrylic resins, epoxy resins, urethane resins, phenol resins, cellulose derivatives, polymaleic acid, and polyester resins.

  The lubricating film contains a lubricant, and the mass ratio of lubricant / (water-soluble silicate + water-soluble tungstate) is preferably 0.01 to 1.5.

  The lubricant is preferably at least one selected from wax, polytetrafluoroethylene, fatty acid soap, fatty acid metal soap, fatty acid amide, molybdenum disulfide, tungsten disulfide, graphite, and melamine cyanurate.

The film mass per unit area of the lubricating film is preferably 1.0 to 20 g / m ² .

  In the steel wire rod of the present invention, since the lubricating film is configured as described above, the steel wire rod has excellent corrosion resistance such as wire drawability, spike property, ball ironing property, workability such as film removal property, and long-term rust prevention property. Is obtained. Moreover, the point that all of these performances are equivalent to or better than that of a steel wire having a chemical conversion coating is a great advantage compared to conventional water-based lubricating coatings.

FIG. 1 shows evaluation criteria for seizure when evaluating the ball ironing property.

  The present invention provides a lubricating film containing a water-soluble silicate and a water-soluble tungstate, wherein the mass ratio of water-soluble tungstate / water-soluble silicate is in the range of 0.7 to 10, and does not contain phosphorus. The present invention relates to a steel wire characterized by having on the surface.

  In the present invention, the steel used for the steel wire includes carbon steel, alloy steel, special steel and the like. As such steel, carbon steel having a carbon content of 0.2% by mass or less (excluding 0% by mass) to carbon steel having a carbon content of more than 0.2% by mass and not more than 1.5% by mass, and uses of mild steel or carbon steel Depending on the above, alloy steel or special steel containing at least one selected from silicon, manganese, phosphorus, sulfur, nickel, chromium, copper, aluminum, molybdenum, vanadium, cobalt, titanium, zircon and the like can be mentioned. In the present invention, the steel wire generally refers to steel processed into a wire by hot working. The steel wire material of the present invention includes a steel wire. With steel wire, steel wire was further processed, such as steel wire drawn to specified size (wire diameter, roundness, etc.), steel wire or drawn steel wire plated Say things.

The steel wire of the present invention is not particularly limited as long as it has a lubricating film described later and has excellent corrosion resistance and workability, but a further film, that is, a base film is formed between the surface of the steel wire and the lubricating film. May be. Any of these films may be a single layer or two or more layers.
The lubricating film and the base film do not contain phosphorus, and the lubricating film treating agent used for forming the film does not contain a component containing phosphorus. However, in the present invention, it is not excluded that a component containing phosphorus is inevitably mixed in the coating on the surface of the steel wire in the operation process or the like. That is, even if phosphorus is contaminated as an inevitable impurity in actual operation, if phosphorus is contained in an amount of about 1% by mass or less, it is unlikely that the steel wire will be brittlely broken by such phosphorus. It can be assumed that phosphorus does not occur.

  Hereinafter, each component, composition, etc. of the lubricating film in the steel wire according to the present invention will be described in order.

  The steel wire rod of the present invention includes a water-soluble silicate and a water-soluble tungstate, and a lubricating film having a water-soluble tungstate / water-soluble silicate mass ratio in the range of 0.7 to 10 on the surface. Must have. Lubrication with high corrosion resistance, workability, sufficient adhesion, and film-removability that could not be achieved with water-soluble silicates, water-soluble tungstates alone, or other water-soluble inorganic salts. A film can be formed.

  For example, when a water-soluble silicate and a water-soluble tungstate described later are combined to form a lubricating film, the water-soluble tungstate is incorporated into the network structure formed by the water-soluble silicate. . As mentioned above, the disadvantage of water-soluble tungstate is largely due to the formation of a crystalline film, but by incorporating it into the network structure of water-soluble silicate, water-soluble tungstate is present uniformly and finely. Will be able to. As a result, the properties of the water-soluble silicate that hardly permeate moisture and the passive film having the self-healing function of the water-soluble tungstate are compatible, and the corrosion resistance is remarkably improved.

  Moreover, improvement of processability and film removal property is mentioned as an influence which water-soluble tungstate has on water-soluble silicate. As mentioned above, the reason why water-soluble silicates are inferior in processability and film removal is due to the formation of a strong continuous film by polymerizing water-soluble silicates. By interposing the tungstate in the network structure of the water-soluble silicate, the formation of a strong network structure can be appropriately inhibited, and the workability and film removal can be improved.

  The ratio of the amount of water-soluble silicate and the amount of water-soluble tungstate is important for the development of the above performance. The mass ratio of water-soluble tungstate / water-soluble silicate is 0.7 or more, preferably 0.9 or more, more preferably 1.1 or more. The mass ratio is 10 or less, preferably 6.0 or less, and more preferably 3.0 or less. When the mass ratio of the water-soluble tungstate / water-soluble silicate is less than 0.7, sufficient corrosion resistance and workability cannot be obtained, and a film having poor film removal properties is obtained. This is because the passive film is not sufficiently formed due to the relatively small amount of tungsten, and a strong network structure is formed when the silicate amount is relatively increased. When the mass ratio of the water-soluble tungstate / water-soluble silicate exceeds 10, a film in which sufficient corrosion resistance and workability cannot be obtained. This is due to the fact that the amount of water-soluble silicate is relatively reduced, so that moisture easily permeates, and tungsten crystals are precipitated, resulting in a decrease in the adhesion and uniformity of the film.

  By combining water-soluble silicate and water-soluble tungstate at an appropriate ratio in this way, it is possible to achieve high processability that could not be achieved by the synergistic effect and high corrosion resistance in a practical environment, and at the same time It is possible to form the lubricating film having a good film-removing property. When forming the lubricating film, a lubricating film treating agent containing a water-soluble silicate and a water-soluble tungstate may be prepared and applied to the surface of the steel wire.

  In the present invention, the lubricating film is a composition comprising a water-soluble silicate and a water-soluble tungstate so that the mass ratio of water-soluble tungstate / water-soluble silicate is in the range of 0.7 to 10. It may be formed using.

In the lubricating film, the mass ratio of tungsten / silicon is preferably 1.3 or more, more preferably 1.8 or more, and further preferably 2.0 or more. The mass ratio is preferably 18 or less, more preferably 10 or less, and still more preferably 5.4 or less.
When the mass ratio of tungsten / silicon is less than 1.3, sufficient corrosion resistance and workability cannot be obtained, and a film having poor film removal properties is obtained. This is because the amount of the tungstate is relatively reduced, the passive film is not sufficiently formed, and the amount of the silicate is relatively increased to form a strong network structure. To do. When the mass ratio of tungsten / silicon exceeds 18, a film in which sufficient corrosion resistance and workability cannot be obtained. This is due to the fact that the amount of silicate becomes relatively small and moisture can easily permeate, the crystals of the tungstate precipitate, and the adhesion and uniformity of the film are lowered. In the present invention, the mass ratio of tungsten / silicon is based on the ratio of the tungsten element derived from the water-soluble tungstate and the silicon element derived from the water-soluble silicate in the film, for example, inductively coupled plasma. Alternatively, it can be calculated using fluorescent X-ray analysis.

  Examples of the water-soluble silicate used in the lubricant film treating agent include lithium silicate, sodium silicate, and potassium silicate. These may be used alone or in combination of two or more.

  Examples of the water-soluble tungstate used in the lubricant film treating agent include lithium tungstate, sodium tungstate, potassium tungstate, and ammonium tungstate. These may be used alone or in combination of two or more.

  Next, the resin will be described. The resin is blended in the film for the purpose of binder action, improvement of adhesion between the substrate and the film, leveling by thickening action, and stabilization of the dispersed component. Examples of resins having such functions and properties include vinyl resins, acrylic resins, epoxy resins, urethane resins, phenol resins, cellulose derivatives, polymaleic acid, and polyester resins. These may be used alone or in combination of two or more.

  In the present invention, the lubricating film contains a resin, and the mass ratio of resin / (water-soluble silicate + water-soluble tungstate) is preferably 0.01 or more, more preferably 0.05 or more. . Moreover, it is preferable that the said mass ratio is 1.5 or less, More preferably, it is 1.0 or less. When the mass ratio is less than 0.01, the above-mentioned action is not sufficiently exhibited. When the mass ratio exceeds 1.5, the amount of the water-soluble silicate and the water-soluble tungstate is relatively small and sufficient. Processability and corrosion resistance cannot be realized.

  Next, the lubricant will be described. The lubricant itself is slippery and has a function of reducing the frictional force. Generally, when the frictional force increases during plastic processing, processing energy increases, heat generation, seizure, etc. occur, but if lubricant is included in the lubricant coating agent used in the present invention, it exists in a solid form in the lubricant coating. Thus, an increase in frictional force is suppressed. Examples of the lubricant having such functions and properties include wax, polytetrafluoroethylene, fatty acid soap, fatty acid metal soap, fatty acid amide, molybdenum disulfide, tungsten disulfide, graphite, and melamine cyanurate. These may be used alone or in combination of two or more.

  Specific examples of the wax include polyethylene wax, paraffin wax, microcrystalline wax, polypropylene wax, and carnauba wax. Specific examples of the fatty acid soap include sodium myristate, potassium myristate, sodium palmitate, potassium palmitate, sodium stearate, and potassium stearate. Specific examples of the fatty acid metal soap include calcium stearate, zinc stearate, barium stearate, magnesium stearate, and lithium stearate. The fatty acid amide is, for example, an amide compound having two fatty acids. Specific examples include ethylene bislauric acid amide, ethylene bis stearic acid amide, ethylene bisbehenic acid amide, N, N′-distearyl adipic acid amide, ethylene bis oleic acid. Amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide may be mentioned.

  When a lubricant is blended in the lubricating film, the mass ratio of lubricant / (water-soluble silicate + water-soluble tungstate) is preferably 0.01 or more, more preferably 0.05 or more. The mass ratio is preferably 1.5 or less, more preferably 1.0 or less. If the mass ratio of lubricant / (water-soluble silicate + water-soluble tungstate) is less than 0.01, the above performance cannot be exhibited because the amount of lubricant is too small. When the mass ratio exceeds 1.5, the amount of the water-soluble silicate and the water-soluble tungstate becomes relatively small, and the high corrosion resistance and workability that are the characteristics of the present invention cannot be expressed.

  In addition to water-soluble silicates, water-soluble tungstates, resins, and lubricants, the lubricating film of the steel wire rod of the present invention is leveled to ensure a uniform application state when a lubricant treatment liquid is applied to a substrate. A viscosity modifier can be blended for the purpose of imparting properties and thixotropy. In addition, as for these compounding quantities, 0.1-30 mass% is preferable with respect to the total solid content mass. Specific examples of such viscosity modifiers include smectite clay minerals such as montmorillonite, saconite, beidellite, hectorite, nontronite, saponite, iron saponite and stevensite, and inorganic thickening such as finely divided silica, bentonite and kaolin. Agents.

The lubricating coating may contain an inorganic salt such as sulfate or borate, or a water-soluble salt such as organic salt in order to improve adhesion and workability. Examples of the sulfate include sodium sulfate and potassium sulfate. Examples of the borate include sodium metaborate, potassium metaborate, and ammonium metaborate.
Organic salts include formic acid, acetic acid, butyric acid, oxalic acid, succinic acid, lactic acid, ascorbic acid, tartaric acid, citric acid, malic acid, malonic acid, maleic acid, phthalic acid, etc. and alkali metals, alkaline earth metals, etc. Salt.

  The lubricating coating of the steel wire rod of the present invention can impart high corrosion resistance before and after processing, but may further contain other water-soluble rust preventives and inhibitors for the purpose of further improving the corrosion resistance. Specific examples include various organic acids such as oleic acid, dimer acid, tartaric acid and citric acid, various chelating agents such as EDTA, NTA, HEDTA and DTPA, mixed components of alkanolamine such as triethanolamine, and p-t-butylbenzoic acid. Known amines such as carboxylic acid amine salts, dibasic acid amine salts, alkenyl succinic acid and water-soluble salts thereof, and aminotetrazole and water-soluble salts thereof can be used. These may be used alone or in combination of two or more. These compounding amounts are preferably 0.1 to 30% by mass relative to the total solid mass.

In the present invention, the lubricant film treatment agent contains the water-soluble silicate and the water-soluble tungstate as essential components, and contains the resin, the lubricant, and the water-soluble salt as necessary.
The water-soluble silicate is preferably more than 5% by mass in 100% by mass of the lubricant film treatment agent, more preferably 10% by mass or more, still more preferably 15% by mass or more, and 58% by mass or less. It is preferable that it is preferably 52% by mass or less, and more preferably 45% by mass or less.
The water-soluble tungstate is preferably 10% by mass or more, more preferably 15% by mass or more, further preferably 20% by mass or more, and 91% by mass or less, in 100% by mass of the lubricant film treatment agent. It is preferable that the content is 85% by mass or less, more preferably 80% by mass or less.
When the amount of the water-soluble silicate is 5% by mass or less and the amount of the water-soluble tungstate is more than 91% by mass, sufficient long-term rust preventive property cannot be obtained, and wire drawing property and ball ironing property are obtained. The film is inferior. This is due to the fact that the amount of water-soluble silicate is relatively reduced, so that moisture easily permeates, and tungsten crystals are precipitated, resulting in a decrease in the adhesion and uniformity of the film. When the amount of the water-soluble silicate is more than 58% by mass and the amount of the water-soluble tungstate is less than 10% by mass, a film with insufficient corrosion resistance and workability cannot be obtained. This is because a relatively thin passive film is not formed due to a relatively small amount of tungsten, and a strong network structure is formed due to a relatively large amount of water-soluble silicate.

  In the present invention, the lubricating film may be formed as a base lubricating film for a dry lubricant. By using it as an undercoat of a dry lubricant, the lubricity, seizure resistance, and corrosion resistance can be raised. The type of dry lubricant is not particularly limited, and general lubricating powders and wire drawing powders mainly composed of higher fatty acid soap, borax, lime, molybdenum disulfide, etc. can be used.

  In the present invention, the liquid medium (solvent, dispersion medium) in the film treatment agent for forming the lubricating film is water. In order to shorten the drying time of the lubricant in the drying process, an alcohol having a boiling point lower than that of water may be blended.

  The lubricating film treating agent may contain a water-soluble strong alkali component in order to increase the stability of the liquid. Specific examples include lithium hydroxide, sodium hydroxide, and potassium hydroxide. These may be used alone or in combination of two or more. These compounding amounts are preferably 0.01 to 10% by mass relative to the total solid mass.

  Lubricant treatment agent used in the present invention should be mixed by adding water-soluble silicate and water-soluble tungstate, resin, lubricant, and viscosity modifier if necessary to water which is a liquid medium. Manufactured by. The water-soluble silicate and water-soluble tungstate used here are water-soluble, but some resins, lubricants, viscosity modifiers, etc. are insoluble or sparingly soluble in water. Need to be distributed. If necessary, the dispersing method is carried out by adding a surfactant that can be a dispersing agent to water and sufficiently blending in water, and then stirring is continued until the dispersed state becomes uniform. The stirring method is performed by a general method such as propeller stirring or stirring with a homogenizer. In addition, in order to obtain a stable dispersion state, a known surfactant can be used.

  Next, the manufacturing method of the steel wire concerning the present invention is explained. The method of the present invention includes a steel wire rod cleaning step, a film treatment agent manufacturing step, and a drying step. Hereinafter, each step will be described.

・ Cleaning process (pretreatment process)
Before forming the lubricating film on the steel wire, it is preferable to perform at least one type of cleaning treatment selected from the group consisting of shot blasting, sand blasting, wet blasting, peeling, alkali degreasing and acid cleaning. The purpose of cleaning here is to remove oxide scales and various types of dirt (oil, etc.) grown by annealing or the like.

-Lubricant film manufacturing process In this invention, although the process which manufactures a lubricating film to a steel wire is not specifically limited, Application | coating, such as a dipping method, a flow coat method, a spray method, can be used. The coating is only required to be sufficiently covered with the lubricating film treating agent of the present invention, and the coating time is not particularly limited. Here, in order to increase the drying property, the steel wire may be heated to 60 to 80 ° C. and brought into contact with the lubricant coating agent. Moreover, you may make the lubricating film processing agent heated at 40-70 degreeC contact. By these, drying property improves significantly and drying may be attained at normal temperature, and the loss of heat energy can also be reduced.

-Drying process Next, it is necessary to dry the said lubricating film processing agent. Drying may be performed at room temperature, but may be performed at 60 to 150 ° C. for 1 to 30 minutes.

Here, the film mass of the lubricating film formed on the steel wire is appropriately controlled by the degree of subsequent processing, but the film mass is preferably 1.0 g / m ² or more, more preferably 2.0 g. / M ² or more, preferably 20 g / m ² or less, more preferably 15 g / m ² or less. When the film mass is small, the workability is insufficient. On the other hand, when the coating mass exceeds 20 g / m ² , workability is not a problem, but it is not preferable because clogging of the dies is caused. The film mass can be calculated from the mass difference and surface area of the steel wire before and after the treatment. In order to control so that it may become the above-mentioned film mass range, solid content mass (concentration) of a lubricating film processing agent is adjusted suitably. In practice, a high-concentration lubricant is often diluted with water and used in the treatment liquid. The water to be diluted is not particularly limited. For example, pure water, deionized water, tap water, ground water, industrial water, and the like can be used.

-Film removal method In the present invention, the lubricant film formed by the lubricant film treatment agent can be removed by dipping in a water-based alkaline cleaner or by spray cleaning. The alkaline cleaner is a solution in which a general alkali component such as sodium hydroxide or potassium hydroxide is dissolved in water. When the lubricant film is brought into contact with this, the lubricant film dissolves in the cleaning solution, so that it can be easily removed. Can be membrane. Moreover, it can be set as the film | membrane which is easy to drop off by the heat processing after a process. Therefore, it is possible to prevent contamination and plating defects in the subsequent process due to defective film removal by alkali cleaning or heat treatment.

  Hereinafter, about the case where steel wire material is made into a target, by giving an example with a comparative example, it explains still more concretely with the effect of the present invention. In addition, this invention is not restrict | limited by these Examples. In the following, “part” means “part by mass” and “%” means “% by mass” unless otherwise specified.

(1-1) Preparation of Lubricant Treatment Agents Lubricant treatment agents of Examples 1 to 18 and Comparative Examples 1 to 12 were prepared in the combinations and proportions shown in Table 1 below. Comparative Example 13 is a phosphate / soap treatment.

<Water-soluble silicate>
(A-1) Sodium metasilicate (A-2) No. 3 sodium silicate (Na ₂ O · nSiO ₂ n = 3)
(A-3) Lithium silicate (Li ₂ O.nSiO ₂ n = 3.5)
<Water-soluble tungstate>
(B-1) Ammonium tungstate (B-2) Sodium tungstate (B-3) Lithium tungstate <Resin>
(C-1) Polyvinyl alcohol (average molecular weight of about 50,000)
(C-2)) Sodium neutralized salt of isobutylene / maleic anhydride copolymer (average molecular weight of about 165,000)
<Lubricant>
(D-1) Anionic polyethylene wax (average particle size 5 μm)
(D-2) Ethylene bis stearic acid amide <water-soluble salt>
(E-1) Sodium metaborate (E-2) Sodium tartrate (E-3) Sodium sulfate (E-4) Sodium pyrophosphate <Undercoat>
(F-1) Zirconium chemical conversion treatment agent (Pulseed (registered trademark) 1500, manufactured by Nihon Parkerizing Co., Ltd.)

(1-2) Lubricant film treatment Each lubricant film treatment was performed on the surface of a sample steel wire (steel type: S45C) having a diameter of 3.2 mm in the following steps.

<Pretreatment and Lubricant Film Treatment of Examples 1-15 and Comparative Examples 2-12>
(A) Degreasing: Commercially available degreasing agent (Fine Cleaner (registered trademark) E6400, manufactured by Nippon Parkerizing Co., Ltd.), concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, room temperature, immersion 20 seconds (C) Pickling: 17.5% hydrochloric acid, room temperature, immersion for 20 minutes (d) Water washing: tap water, room temperature, immersion for 20 seconds (e) Neutralization: Commercial neutralizer (preparene (registered trademark) 27, Japan Parkerizing Co., Ltd.)
(F) Lubricant film treatment: Lubricant film treatment agent prepared in (1-1) Temperature 60 ° C., immersion 1 minute (g) Drying: 100 ° C., 10 minutes (h) Lubricant film amount is appropriately adjusted by treatment agent concentration

<Pretreatment and Lubricating Film Treatment of Examples 16-18>
(A) Degreasing: Commercial degreasing agent (Fine Cleaner (registered trademark) 6400, manufactured by Nihon Parkerizing Co., Ltd.), concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, normal temperature, immersion 30 seconds (C) Pickling: hydrochloric acid, concentration 17.5%, normal temperature, immersion 10 minutes (d) Water washing: tap water, normal temperature, immersion 30 seconds (e) Zirconium treatment: Commercial zirconium conversion treatment agent (Pulseed (registered trademark)) 1500, manufactured by Nihon Parkerizing Co., Ltd.) Concentration 50 g / L, temperature 45 ° C., immersion 2 minutes (f) Washing with water: tap water, room temperature, immersion 30 seconds (g) Lubricating film treatment: lubrication manufactured with (1-1) Film treatment agent Temperature 60 ° C., immersion 1 minute (h) Drying: 100 ° C., 10 minutes (i) Undercoat film amount: Zirconium undercoat 50 mg / m ² , Lubricant film amount is appropriately adjusted by treatment agent concentration

<Processing of Comparative Example 1>
(A) Degreasing: Commercial degreasing agent (Fine Cleaner (registered trademark) 6400, manufactured by Nihon Parkerizing Co., Ltd.), concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, normal temperature, immersion 30 seconds (C) Pickling: hydrochloric acid, concentration 17.5%, room temperature, immersion 10 minutes (d) Water washing: tap water, room temperature, immersion 30 seconds (e) pure water washing: deionized water, room temperature, immersion 30 ° C.
(F) Drying: 100 ° C. for 10 minutes

<Pretreatment and film treatment of Comparative Example 13 (phosphate / soap treatment)>
(A) Degreasing: Commercial degreasing agent (Fine Cleaner (registered trademark) 6400, manufactured by Nihon Parkerizing Co., Ltd.), concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, normal temperature, immersion 30 seconds (C) Pickling: hydrochloric acid, concentration 17.5%, normal temperature, immersion 10 minutes (d) Washing: tap water, normal temperature, immersion 30 seconds (e) Chemical conversion treatment: commercial zinc phosphate chemical conversion agent (Palbond (registered) (Trademark) 3696X, manufactured by Nihon Parkerizing Co., Ltd.) Concentration 75 g / L, temperature 80 ° C., immersion 10 minutes (f) Water washing: tap water, room temperature, immersion 30 seconds (g) Soap treatment: commercially available reactive soap lubricant (Paloub) (Registered trademark) 235, manufactured by Nippon Parkerizing Co., Ltd.) Concentration 70 g / L, temperature 85 ° C., immersion 3 minutes (h) drying: 100 ° C., 10 minutes (i) coating amount: 10 g / m ²

(1-3) Evaluation test (1-3-1) Workability (drawing property) test A drawing wire was drawn by drawing a φ3.2 mm × 20 m sample wire through a φ2.76 die. A missile C40 from Matsuura Kogyo Co., Ltd. was used as a dry lubricant. A dry lubricant was placed in the die box just before the material was pulled out so that it naturally adhered to the material. Evaluation was performed from seizure of the test material after wire drawing and the remaining amount of the lubricating film. In addition, the drawing of the phosphate / soap film of Comparative Example 13 does not use a dry lubricant in accordance with a normal usage method.
Evaluation criteria A: No seizure and no metallic luster. A lot of film remains on the whole.
○: There is no seizure and no metallic luster is observed, but the remaining film is slightly less than ◎.
Δ: Although there is no seizure, the remaining amount of the film is slightly small, and a metallic luster is recognized in part.
▲: There is no seizure, but metallic luster is observed in many parts.
X: Seizure occurred.

(1-3-2) Corrosion resistance (long-term rust prevention) test The wire material subjected to the above wire drawing test was exposed indoors in an open atmosphere in the summer for two weeks or two months, and the occurrence of rust was observed. It was judged that the larger the rusting area, the lower the corrosion resistance.
Evaluation standard ◎: Remarkably superior to phosphate / soap coating (rust area 3% or less)
○: Superior to phosphate / soap coating (rust area over 3% to 10% or less)
Δ: Equivalent to phosphate / soap coating (rust area over 10% to 20% or less)
▲: Inferior to phosphate / soap film (rust area more than 20% to 30% or less)
X: Remarkably inferior to phosphate / soap film (rust area over 30%)

  The test results are shown in Table 2. In all of the examples, rust was hardly generated over a long period of time, the corrosion resistance was good, and a lot of the lubricating film remained, resulting in good workability. Moreover, higher corrosion resistance was shown by performing a zirconium chemical conversion treatment as a base treatment. Comparative Example 1 is an example in which the lubricating film used in the examples is not formed, but seizure occurs at the time of wire drawing, rust frequently occurs in both 2 weeks and 2 months, and is not suitable as a practical level. there were. In Comparative Examples 2 to 9, the ratio of the water-soluble silicate and the water-soluble tungstate is set outside the scope of the present invention, but the workability is inferior and the corrosion resistance is also low because the film remaining after wire drawing is small. It was inferior. Comparative Examples 10 to 12 contain components other than silicates and tungstates as water-soluble inorganic salts, but the workability and corrosion resistance were inferior due to the small amount of film remaining after wire drawing. . Although the phosphate soap film of Comparative Example 13 treated with a reactive soap exhibits phosphorus with relatively good performance, it contains phosphorus, so that it was immersed in a heat treatment such as quenching and tempering while having a lubricating film on the surface. Since the steel wire may be fragile, it is out of the scope of the present invention. Similarly, Comparative Examples 9 and 10 are also outside the scope of the present invention because they contain phosphorus.

  By giving an example together with a comparative example for a steel wire, the effect of the present invention will be described more specifically. In addition, this invention is not restrict | limited by these Examples. In the following, “part” means “part by mass” and “%” means “% by mass” unless otherwise specified.

(2-1) Preparation of Lubricating Film Treatment Agent Lubricating film treatment agents of Examples 19 to 38 and Comparative Examples 14 to 25 were prepared in the combinations and proportions shown in Table 3 for the components shown below. In addition, the comparative example 26 is a phosphate / soap treatment.

<Water-soluble silicate>
(A-1) Sodium metasilicate (A-2) No. 3 sodium silicate (Na ₂ O · nSiO ₂ n = 3)
(A-3) Lithium silicate (Li ₂ O.nSiO ₂ n = 3.5)
<Water-soluble tungstate>
(B-1) Ammonium tungstate (B-2) Sodium tungstate (B-3) Lithium tungstate <Resin>
(C-1) Polyvinyl alcohol (average molecular weight of about 50,000)
(C-2) Sodium neutralized salt of isobutylene / maleic anhydride copolymer (average molecular weight of about 165,000)
(C-3) Sodium carboxymethylcellulose (average molecular weight of about 30,000)
(C-4) Water-based nonionic urethane resin emulsion <Lubricant>
(D-1) Anionic polyethylene wax (average particle size 5 μm)
(D-2) Ethylene bis stearic acid amide (D-3) Calcium stearate (D-4) Polytetrafluoroethylene dispersion (average particle diameter 0.2 μm)
<Water-soluble salt>
(E-1) Sodium metaborate (E-2) Sodium tartrate (E-3) Sodium sulfate (E-4) Sodium pyrophosphate <Undercoat>
(F-1) Zirconium chemical conversion treatment agent (Pulseed (registered trademark) 1500, manufactured by Nihon Parkerizing Co., Ltd.)

(2-2) Lubricating film treatment The following lubricating film treatment was performed on various test pieces for evaluation assuming a bolt manufacturing process which is a processing target of a steel wire.

<Pretreatment and Lubricating Film Treatment of Examples 19 to 35 and Comparative Examples 14 to 25>
(A) Degreasing: Commercially available degreasing agent (Fine Cleaner (registered trademark) E6400, manufactured by Nippon Parkerizing Co., Ltd.), concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, room temperature, immersion 20 seconds (C) Pickling: 17.5% hydrochloric acid, room temperature, immersion for 20 minutes (d) Water washing: tap water, room temperature, immersion for 20 seconds (e) Neutralization: Commercial neutralizer (preparene (registered trademark) 27, Japan Parkerizing Co., Ltd.)
(F) Lubricant film treatment: Lubricant film treatment agent produced in (2-1) Temperature 60 ° C., immersion 1 minute (g) Drying: 100 ° C., 10 minutes (h) Lubricant film amount is appropriately adjusted by treatment agent concentration

<Pretreatment and Lubricating Film Treatment of Examples 36 to 38>
(A) Degreasing: Commercial degreasing agent (Fine Cleaner (registered trademark) 6400, manufactured by Nihon Parkerizing Co., Ltd.), concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, normal temperature, immersion 30 seconds (C) Pickling: hydrochloric acid, concentration 17.5%, normal temperature, immersion 10 minutes (d) Water washing: tap water, normal temperature, immersion 30 seconds (e) Zirconium treatment: Commercial zirconium conversion treatment agent (Pulseed (registered trademark)) 1500, manufactured by Nihon Parkerizing Co., Ltd.) Concentration 50 g / L, temperature 45 ° C., immersion 2 minutes (f) Washing water: tap water, room temperature, immersion 30 seconds (g) Lubricating film treatment: lubrication manufactured in (2-1) Film treatment agent Temperature 60 ° C., immersion 1 minute (h) Drying: 100 ° C., 10 minutes (i) Undercoat film amount: Zirconium undercoat 50 mg / m ² , Lubricant film amount is appropriately adjusted by treatment agent concentration

<Pretreatment and film treatment of Comparative Example 26 (phosphate / soap treatment)>
(A) Degreasing: Commercial degreasing agent (Fine Cleaner (registered trademark) 6400, manufactured by Nihon Parkerizing Co., Ltd.), concentration 20 g / L, temperature 60 ° C., immersion 10 minutes (b) water washing: tap water, normal temperature, immersion 30 seconds (C) Pickling: hydrochloric acid, concentration 17.5%, normal temperature, immersion 10 minutes (d) Washing: tap water, normal temperature, immersion 30 seconds (e) Chemical conversion treatment: commercial zinc phosphate chemical conversion agent (Palbond (registered) (Trademark) 3696X, manufactured by Nihon Parkerizing Co., Ltd.) Concentration 75g / L, Temperature 80 ° C, Immersion 7 minutes (f) Washing water: tap water, room temperature, immersion 30 seconds (g) Soap treatment: Commercially available reactive soap lubricant (Palube) (Registered trademark) 235, manufactured by Nihon Parkerizing Co., Ltd.) Concentration 70 g / L, temperature 85 ° C., immersion 3 minutes (h) drying: 100 ° C., 10 minutes (i) coating amount: 10 g / m ²

(2-3) Evaluation test (2-3-1) Workability (spike property) test A spike test was conducted as a test assuming shaft drawing when a steel wire was processed into a bolt. The spike test was conducted according to the description in JP-A-5-7969. Lubricity was evaluated by spike height and molding load after the test. The higher the spike height and the lower the molding load, the better the lubricity. According to the above document, the area expansion rate in the spike test is about 10 times. The lubricity of the film was evaluated by measuring the load and spike height during processing.
Test piece for evaluation: S45C spheroidized annealing material 25 mmφ × 30 mm
Evaluation standard spike performance: spike height (mm) / working load (kNf) × 100
The larger the value, the better the spike performance.
A: Remarkably superior to phosphate / soap coating (0.96 or more)
○: Superior to phosphate / soap coating (0.94 or more and less than 0.96)
Δ: Equivalent to phosphate / soap coating (0.92 or more and less than 0.94)
▲: Inferior to phosphate / soap film (0.90 or more and less than 0.92)
X: Remarkably inferior to phosphate / soap film (less than 0.90)

(2-3-2) Workability (upsetting-ball ironing test) An upsetting-ball ironing test was performed as a test assuming the forming of a bolt head when processing a steel wire into a flange bolt or the like. The upsetting-ball ironing test was conducted according to the description in JP2013-215773A. The area expansion rate in the upsetting-ball ironing test is 150 times or more at the maximum, and the area expansion rate is very large as compared with the spike test. Therefore, for example, it is a test that can reproduce a process requiring high workability such as forming the head of a hexagon bolt with a flange. The anti-seizure performance of the film was evaluated by evaluating the amount of seizure entering the ironing surface.
Test piece for evaluation: S10C spheroidized annealing material 14 mmφ × 32 mm
Bearing ball: 10mmφ SUJ2
Evaluation criteria (A to B were evaluated based on the seizure state shown in FIG. 1)
It was evaluated how much area burned with respect to the entire area of the ironing surface.
◎: Remarkably superior to phosphate / soap coating ○: Superior to phosphate / soap coating △: Equivalent to phosphate / soap coating ▲: Inferior to phosphate / soap coating ×: From phosphate / soap coating Markedly inferior

(2-3-3) Film-removability test The film-removability test is a cylindrical test piece, using a flat mold on both the top and bottom, upsetting with a compression ratio of 50%, and immersed in the following alkaline detergent The film residual rate was calculated by measuring the film weight before and after the film removal treatment.
Test piece for evaluation: S45C spheroidized annealing material 25 mmφ × 30 mm
Alkaline detergent: 2% NaOH aqueous solution film removal conditions: liquid temperature 60 ° C., immersion time 2 minutes Treatment method:
Measurement of film weight before film removal treatment → Film removal treatment → Washing → Drying → Film weight measurement after film removal treatment Film remaining rate (%) = (film weight after film removal treatment / film weight before film removal treatment) x 100
Evaluation criteria:
The lower the film remaining rate, the better the film removal performance ◎: The film remaining rate is 0%
○: Film remaining ratio is over 0% to less than 8% Δ: Film remaining ratio is 8% or more to less than 16% ▲: Film remaining ratio is 16% or more to less than 25% ×: Film remaining ratio is 25% or more

(2-3-4) Evaluation of corrosion resistance (long-term rust prevention) The test pieces subjected to the above-mentioned film treatment were exposed indoors in an open atmosphere in summer for 2 weeks or 2 months, and the occurrence of rust was observed. It was judged that the larger the rusting area, the lower the corrosion resistance.
Test piece: SPCC-SD 75mm x 35mm x 0.8mm
Evaluation criteria:
A: Remarkably superior to phosphate / soap coating (rust area 3% or less)
○: Superior to phosphate / soap coating (rust area over 3% to 10% or less)
Δ: Equivalent to phosphate / soap coating (rust area over 10% to 20% or less)
▲: Inferior to phosphate / soap film (rust area more than 20% to 30% or less)
X: Remarkably inferior to phosphate / soap film (rust area over 30%)

The test results are shown in Table 4. As is clear from Table 4, the examples had good workability (spike properties, ball ironing properties, film removal properties) and corrosion resistance (long-term rust prevention properties). Moreover, higher corrosion resistance was shown by performing a zirconium chemical conversion treatment as a base treatment. In Comparative Examples 14 to 21, the ratio of the water-soluble silicate to the water-soluble tungstate was set outside the range of the present invention, but the results of ball ironing property and corrosion resistance tended to be inferior. Comparative Examples 22 to 25 contain components other than water-soluble silicate and water-soluble tungstate as water-soluble inorganic salts, but there was a tendency that the results of ball ironing and corrosion resistance were inferior. Although the phosphate soap film of Comparative Example 26 treated with a reactive soap exhibits relatively excellent performance, it contains phosphorus, so that when the heat treatment such as quenching and tempering is performed with the lubricating film on the surface, phosphorus is immersed. Since there exists a possibility that a steel wire may become weak, it is outside the scope of the present invention. Similarly, Comparative Examples 19 and 22 are also out of the scope of the present invention because they contain phosphorus.
Furthermore, even if the lubricating film contains a water-soluble silicate, the film-removing property was not sufficient when it did not contain a water-soluble tungstate.

  As is clear from the above explanation, the steel wire rod of the present invention does not contain phosphorus, so it has no phosphorus immersion property during heat treatment, and has high workability and corrosion resistance equivalent to or higher than conventional phosphate and soap treatment materials. It can be compatible. Since the film removal property of the lubricating film after processing with a cleaning agent is also good, it contributes to improving the process efficiency when performing post-processes such as plating after processing to bolts and the like. Therefore, the industrial utility value is extremely large.

Claims (7)

  It contains a water-soluble silicate and a water-soluble tungstate, the water-soluble tungstate / water-soluble silicate mass ratio is in the range of 0.7 to 10, and has a phosphorus-free lubricating film on the surface. A steel wire characterized by A steel wire having a lubricating film that does not contain phosphorus,
The lubricating film is formed by using a composition in which a water-soluble silicate and a water-soluble tungstate are mixed so that the mass ratio of water-soluble tungstate / water-soluble silicate is in the range of 0.7 to 10. Steel wire characterized by being made.   The steel wire rod according to claim 1 or 2, wherein the lubricating film contains a resin, and a mass ratio of resin / (water-soluble silicate + water-soluble tungstate) is 0.01 to 1.5.   The steel wire according to claim 3, wherein the resin is at least one selected from vinyl resins, acrylic resins, epoxy resins, urethane resins, phenol resins, cellulose derivatives, polymaleic acid, and polyester resins.   The steel according to any one of claims 1 to 4, wherein the lubricating film contains a lubricant, and a mass ratio of lubricant / (water-soluble silicate + water-soluble tungstate) is 0.01 to 1.5. wire.   The steel according to claim 5, wherein the lubricant is at least one selected from wax, polytetrafluoroethylene, fatty acid soap, fatty acid metal soap, fatty acid amide, molybdenum disulfide, tungsten disulfide, graphite, and melamine cyanurate. wire. Steel wire rod according to any one of claims 1 to 6 coating mass is 1.0 to 20 g / m ² per unit area of the lubricant film.