WO2002072345A1

WO2002072345A1 - Metallic material for plastic working with gradient two-layer lubricant coating film and process for producing the same

Info

Publication number: WO2002072345A1
Application number: PCT/JP2002/002072
Authority: WO
Inventors: Hidehiro Yamaguchi; Yasuo Imai; Masayuki Yoshida
Original assignee: Nihon Parkerizing Co., Ltd.
Priority date: 2001-03-07
Filing date: 2002-03-06
Publication date: 2002-09-19
Also published as: JP4054539B2; JP2002264252A

Abstract

A metallic material for plastic working which has excellent lubricating properties. The metallic material for plastic working has a gradient two-layer lubricant layer which comprises a base layer located on the metal side, having a thickness of 0.1 to 15.0 νm, and comprising an inorganic compound as the main component and a lubricant layer located on the surface side, having a thickness of 0.1 to 10.0 νm, and comprising a lubricant as the main component and in which the ratio of the thickness of the lubricant layer to that of the base layer is from 0.2 to 3.0. The inorganic compound is preferably a phosphate, sulfate, borate, silicate, molybdate, tungstate, etc. The lubricant is preferably a metal soap, wax, polytetrafluoroethylene, molybdenum disulfide, graphite, etc. The metallic material may be iron, steel, stainless steel, etc. The gradient two-layer lubricant layer can be formed by bringing the surface of a metallic material into contact with a water-based treating liquid containing an inorganic compound and a lubricant as major ingredients and then drying the surface.

Description

Description Metallic material for plastic working having a two-layer inclined lubricating film and its manufacturing method

TECHNICAL FIELD The present invention relates to a novel metal material for plastic working having a surface provided with an inclined two-layer lubricating film having excellent lubricity that can withstand plastic working such as forging, drawing, and drawing, and a method for producing the same. Background art

Generally, when plastically processing a metal material such as steel or stainless steel, a lubricating film is formed on the metal surface in order to prevent seizure or galling caused by metal contact between the workpiece and the tool. The lubricating film is of a type in which a lubricant is physically attached to the metal surface and a type in which a chemical conversion film is formed on the metal surface by a chemical reaction and then a lubricant is applied. There is. A lubricating film formed by physically attaching to a metal surface has poor adhesion compared to a lubricating film formed by applying a lubricant after forming a chemical conversion coating on the metal surface, and is generally used for light machining. Used as

In the case where a lubricating film is formed after the formation of a chemical conversion film, a phosphate film or oxalate film, which acts as a carrier, is formed on the surface, and then a slippery lubricant is used. I do. This type has a two-layer structure consisting of a chemical conversion film as a carrier film and a lubricant, and exhibits extremely high seizure resistance. For this reason, it has been used in a very wide range in plastic working fields such as wire drawing, pipe drawing, and forging. In plastic processing, especially in the field where processing is severe, a method of using a phosphate film or an oxalate film as a base and using a lubricant on the base is often used. Lubricants used to form a lubricating film on a chemical conversion coating can be broadly divided into two types depending on the method of use. One is a type in which a lubricant is physically attached to a chemical conversion treatment film, and the other is a type in which a lubricant is reacted and attached to a chemical conversion treatment film. As the former lubricant, mineral oil, vegetable oil and synthetic oil are used as base oils and extreme pressure agents are added to them, or solid lubricants such as graphite and molybdenum disulfide are dissolved in water together with one component of the binder. And those used in the adhesion and drying processes. Since these lubricants can be used more easily by spray coating and dip coating, they have the advantage of requiring almost no liquid management.However, they have low lubricity and can be used for relatively light lubrication. the high _c whereas the latter lubricants, reactive stone鹼such as stearic acid sodium is used. The reactive stone exhibits high lubricity by reacting with the chemical conversion coating, and is particularly suitable when high lubricity is required.

However, the use of reactive stones involving chemical reactions requires liquid management, temperature control to control the chemical reaction, and renewal of disposal due to liquid deterioration. For the purpose of global environmental protection in recent years, reduction of industrial waste has become a major issue. Therefore, there is a need for lubricants and disposal methods that do not generate waste. In addition, in the prior art, simple processing is desired because the management of the process and the processing solution is complicated. Various lubricating film forming compositions and forming methods have been proposed that meet such problems and demands. For example, there is disclosed a lubricant composition comprising a water-soluble polymer or an aqueous emulsion thereof as a base material and a solid lubricant and a chemical conversion film forming agent (Japanese Patent Application Laid-Open No. 52-20967). However, nothing comparable to chemical conversion treatment has been obtained.

In addition, the present applicant has previously described (A) a water-soluble inorganic salt, (B) a solid lubricant, (C) at least one oil component selected from mineral oil, animal and vegetable oils and fats, and (D) an interface component. Water for cold plastic working of metal in which a solid lubricant and oil are uniformly dispersed and emulsified, comprising an activator and (E) water. Although a system-based lubricant was proposed (Japanese Patent Publication No. 10-85085), the lubricant according to the present invention is unstable for industrial use because the oil component is emulsified. High lubricity has not been demonstrated stably.

Further, it contains (A) a synthetic resin, (B) a water-soluble inorganic salt and water, and the solid content weight ratio (B) Z (A) is 0.25 / 1 to 9/1, and the synthetic resin A lubricant composition for plastic working of metallic materials in which is dissolved or dispersed has been proposed (Japanese Patent Publication No. 2000- 638880). However, the lubricant according to the present invention has a synthetic resin as a main component. However, sufficient lubrication has not been stably demonstrated under severe processing conditions. Although the lubricants of these inventions have limited components and ratios, there is no description about the structure of the lubricating film itself, and no specifics have been made.

The present invention is intended to solve the above-mentioned problems of the prior art. In consideration of global environmental conservation, the present invention can be applied to various metal materials, and is a coating-type metal plastic working water which does not require the conventional chemical treatment. An object of the present invention is to provide a plastic working metal material having excellent lubricity by using a system lubricant and further limiting the film structure thereof, and a method for producing the same. Disclosure of the invention

Means for Solving the Problems The present inventors have conducted intensive research on means for solving the above problems, and as a result, formed a base layer having a specific thickness on the metal interface side of the surface, and a lubricant layer having a specific thickness on the surface side. It was found that a metal material for plastic working having an inclined two-layer lubricating film in which the lubricant layer / base layer thickness ratio was a specific value had excellent lubricity. The present inventors have found that an inclined two-layer lubricating film can be obtained by bringing an aqueous treatment solution containing an inorganic compound and a lubricant as main components into contact with a metal surface, and then drying the metal surface, thereby completing the present invention.

That is, the present invention is a metal material for plastic working provided with an inclined two-layer lubricating film comprising a base layer and a lubricant layer on the surface, wherein the pace layer is made of metal. A layer mainly composed of an inorganic compound having a thickness of 0.1 to 15.0 m located on the interface side with the lubricant, and the lubricant layer having a thickness of 0.1 to 10.0 located on the surface side. A metal material for plastic working, which is a layer containing a lubricant of zm as a main component, and having a lubricant layer / base layer thickness ratio of 0.2 to 3.0.

It is preferable that the inorganic compound is at least one selected from the group consisting of-, phosphate, sulfate, borate, silicate, molybdate, and sugestonate. Preferably, it is at least one selected from the group consisting of stone, wax, polytetrafluoroethylene, molybdenum disulfide and graphite. The metal material is preferably iron, steel, stainless steel, aluminum, aluminum alloy, magnesium, magnesium alloy, titanium, titanium alloy, copper, copper alloy, tin, tin alloy, and the like.

In addition, the present invention provides an aqueous treatment solution containing an inorganic compound and a lubricant as a main component in contact with the surface of a metal material, followed by drying, so that the thickness of the inorganic compound as a main component on the interface side with the metal is reduced. A base layer with a thickness of 1 to 15 m is located, and a lubricant layer with a thickness of 0.1 to 10〃m is located on the surface side, and a lubricant layer / base layer thickness ratio. Is a method for producing a metal material for plastic working, characterized by forming an inclined two-layer lubricating film having a ratio of 0.2 to 3. BRIEF DESCRIPTION OF THE FIGURES

1 and 2 are diagrams illustrating a method used for testing the lubrication performance of the metal material for plastic working of the present invention. FIG. 1 is a diagram for explaining the posterior perforation test method, and FIG. 2 is a diagram for explaining the spike test method. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the contents of the present invention will be described in more detail. The plastic working metal of the present invention The metal material has a two-layer inclined lubricating film consisting of a base layer and a lubricant layer on its surface. The inclined type of the inclined two-layer lubricating film in the present invention means that the film layer has a concentration gradient. In other words, the components are not completely divided into two layers (two layers), but the concentration of the lubricant decreases from the outermost surface of the film toward the metal interface, while the concentration of the base component increases. It is a thing. In the present invention, the pace layer has good followability at the time of plastic working, retains a lubricant, and imparts hardness and strength against seizure with a mold. On the other hand, the lubricant layer has the effect of improving the slipperiness of the film and reducing the coefficient of friction. It is important to have two layers, a base layer on the metal side and a lubricant layer on the surface side, and either one does not exhibit lubricity that can withstand plastic working.

The thickness of the base layer is preferably in the range of 0.1 to 15 m, more preferably in the range of 2 to 8 m. If the thickness of the pace layer is less than 0, sufficient lubricant retention cannot be exhibited. On the other hand, if the thickness of the pace layer exceeds 15 m, the film is too thick, and it is not preferable because it is easy to form a flaw during processing. The thickness of the lubricant layer is preferably in the range of 0, 1 m to 10 m, more preferably in the range of 1 to 6 / m. If the thickness of the lubricant layer is less than 0.1 m, sufficient lubricity cannot be obtained. On the other hand, if the thickness exceeds 10 m, surplus scum (adhesion to a mold or the like) is generated during processing, which is not preferable.

The thickness ratio of the lubricant layer paste layer is preferably in the range of 0.2 to 3, and if it is less than 0.2, the whole film is too hard and has poor slipperiness. On the other hand, if the value is 3 or more, the retention is inferior, and the followability as a whole is impaired, which is not preferable. The total thickness of the lubricating film is the sum of the thicknesses of the base layer and the lubricant layer, and ranges from 0.2 to 25 m. If the total film thickness is less than 0.2 zm, the lubricity is insufficient and it cannot withstand severe working plastic deformation. On the other hand, if it exceeds 25 zm, excess waste increases and the cost increases, which is not preferable. The thickness of the total film thickness, the pace layer and lubricants layer of lubricating film is to cut the metal material after the film formation, _c entire film thickness measuring by the cross-section polished and analyzed, especially advanced analytical instruments Is not required and can be observed with a microscope. The thickness of the pace layer and the lubricant layer is measured using EPMA. Quantitative analysis is performed on the film part of the cross section. First, representative elements as main components of the base layer and the lubricant layer are set. For example, if the main component of the base layer is zinc phosphate, it is appropriate to set phosphorus as the representative element, and if the main component of the lubricant layer is ox, it is appropriate to set carbon as the representative element. is there. The quantitative analysis of these two elements is linearly analyzed from the surface to the metal interface. Next, the two abundance ratios are calculated as mole fractions. When the mole fraction is 1 or more, the lubricant layer is used up to 1 or more, and when it is less than 1, the base layer is used. In the actual measurement, of course, this line analysis was performed five or more times with different coating locations in order to correct the data variability and the unevenness of the coating (variation due to the location of the coating). Finally, the thicknesses of the pace layer and the lubricant layer are calculated based on the results.

It is possible to form a graded two-layer film, and in consideration of the followability, adhesion and strength required for the base layer as a lubricating film, and the slipperiness required for the lubricant layer, these components are considered. As a result, it was found that an inorganic compound is preferable as a component of the base layer. As the inorganic compound, it is preferable to use at least one selected from the group consisting of phosphates, sulfates, silicates, borates, molybdates, and tungstates. Examples include zinc phosphate, calcium phosphate, sodium sulfate, potassium sulfate, potassium silicate, sodium borate (sodium tetraborate), potassium borate (potassium tetraborate, etc.), ammonium borate (tetraborate Ammonium molybdate, sodium molybdate, sodium tungstate, and the like. These may be used alone or in combination of two or more. In addition, as the component of the lubricant layer, it is preferable to use at least one selected from the group consisting of metal stone, wax, polytetrafluoroethylene (PTFE), molybdenum disulfide and graphite. In particular, in order to form an inclined two-layer lubricating film, it is more preferable to use a highly hydrophobic fluororesin such as metal stone, wax, or PTFE. Specifically, as the metal stone 、, a saturated fatty acid having 12 to 26 carbon atoms is reacted with at least one metal selected from the group consisting of zinc, calcium, potassium, aluminum, magnesium, and lithium. Examples thereof include calcium stearate, zinc stearate, barium stearate, magnesium stearate, and lithium stearate. Examples of the wax include microcrystalline phosphorus wax, polyethylene wax, polypropylene wax, carnauba wax and the like.

Next, a method of forming the inclined two-layer lubricating film composed of the pace layer and the lubricant layer of the present invention on the surface of the metal material will be described. The inclined two-layer lubricating film is formed by bringing an aqueous treatment liquid containing an inorganic compound and a lubricant as main components into contact with the surface of the metal material, and then drying the same. The specific operation will be described. In addition, it is considered that the inclined two-layer lubricating film is formed by the following theory. First, a processing liquid in which the paste layer component and the lubricant layer component are uniformly dissolved or dispersed is prepared. This treatment liquid is applied to the surface of the metal material. A thin film of the treatment liquid is formed on the surface of the metal material. Then, (1) If the metal material is heated beforehand to a temperature higher than the temperature of the processing solution and then applied, the temperature of the metal material is higher than the temperature of the processing solution. The temperature of the liquid interface is high, the temperature of the gas-liquid interface is low, a temperature difference is created in the thin film of the processing solution, and water as a solvent is volatilized, causing minute convection in the thin film. If (2) a room temperature metal material is coated with a room temperature processing solution, a thin film of the processing solution is formed on the surface of the metal material, and then dried by blowing hot air, the temperature of the gas-liquid interface will be high. Become The surface tension at the interface decreases, and a small convection occurs in the thin film of the processing solution to alleviate this, and a so-called Benal cell is generated.

In both cases (1) and (2), convection occurs, and components are separated into components with high affinity for air and components with high affinity for metals and water. When water gradually evaporates to form a final film, specific components become rich on the gradient film where the concentration gradient of the components occurs, that is, on the interface side with the metal and on the opposite surface side. This causes a component difference. In addition to the above, even when a film is formed after the solvent water has volatilized, by heating to an appropriate temperature, a specific substance in the film diffuses (bleeds) into the film and becomes more stable. In order to be in a state of being in a state, a component difference occurs. Therefore, it is considered that by selecting a component that takes these physicochemical properties into consideration, a graded two-layer lubricating film can be formed by pre-coating, drying, or subsequent heating.

As described above, the formation of the lubricating film on the surface of the metal material according to the present invention is formed by bringing the metal material into contact with the treatment liquid and then drying it, and is the formation of an unreacted lubricating film. . Then, for the purpose of promoting the formation of the inclined two-layer lubricating film, a known thickener or surfactant may be added to the treatment liquid as needed. For example, a viscous agent is effective for improving smoothness and suppressing film unevenness. Further, a polymer compound or the like may be added as one component of the binder in order to increase the adhesion of the film.

Preferred metal materials for the present invention are iron, steel, stainless steel, aluminum, aluminum alloy, magnesium, magnesium alloy, titanium, titanium alloy, copper, copper alloy, tin, and tin alloy. The shape of the metal material is not limited to a material such as a bar material or a block material, and may be a forged shape (gear, shaft, etc.), and is not particularly limited. In the present invention, a shotplast is used before the metal material is brought into contact with the above-mentioned processing solution. It is preferable to perform at least one type of cleaning treatment selected from the group consisting of sandblasting, degreasing and acid cleaning. The purpose of cleaning here is to remove oxide scales and various stains (oil, etc.) grown by annealing or the like.

The thickness of the lubricating film formed on the metal surface of the present invention is adjusted to a specified thickness by appropriately controlling the amount of the treatment liquid applied and the concentrations of the inorganic compound and the lubricant in the treatment liquid. Although the amount of application is not particularly limited, it is generally 10 to 100 gZm ² . The concentrations of the inorganic compound and the lubricant are not particularly limited, but are generally 0.1 to 30% by weight. In addition, the contact time, the contact temperature, and the like are not particularly limited. Although the contact method is not particularly limited, a dipping method, a flow coating method, a spray method, or the like can be used. The drying method is not particularly limited, but a method is used in which a metal material workpiece to be treated is heated in advance and dried using this heat, a method using dry air, a method of blowing hot air, or the like. can do. Example

Examples of the present invention will be described together with comparative examples, and the effects thereof will be described more specifically.

• Posterior drilling test specimen

The material used for the posterior drilling test was a commercially available S45C spheroidized annealed material. The specimen was cylindrical, 3 mm in diameter and 2 mm in height from 18 to 40 mm in height. It is changed in.

• Spike specimens

The material subjected to the spike test was a commercially available S 45 C spheroidized annealed material, and the test piece was cylindrical, 25 mm in diameter (^, 30 mm in height). is there.

Treatment liquid 1.

Base layer component: Zinc phosphate

Lubricant layer component: zinc stearate

Lubricant Z inorganic compound ratio: 0.6

Solid content: 3% by weight

Processing solution 2.

Base layer component: zinc phosphate sodium tetraborate (weight ratio 1: 2) Lubricant layer component: zinc stearate + calcium stearate (weight ratio lubricant / inorganic compound ratio: 1.0

Solid content concentration: 10% by weight

Processing solution 3.

Base layer component: Potassium tetraborate

Lubricant layer component: Micro Chris Yu phosphorus wax

Lubricant ratio of inorganic compound: 0.3.

Solid concentration: 5% by weight

Processing solution 4.

Base layer component: Potassium sulfate potassium tetraborate (weight ratio 1: 1) Lubricant layer component: PTF E

Lubricant / inorganic compound ratio: 0.3

Solid concentration: ²⁰ % by weight

Processing solution 5.

Pace layer component: sodium tetraborate

Lubricant layer components: calcium stearate + polyethylene wax (weight ratio 1: 2)

Lubricant / inorganic compound ratio: 3.0 Solid content concentration: 10% by weight

Treatment solution 6.

Base layer component: sodium tetraborate

Lubricant layer component: None

Solid content concentration: 10% by weight

Treatment liquid Ί.

Pace layer component: None

Lubricant layer component: polyethylene wax

Solid concentration: 10% by weight

Examples 1 to 5

The above material was degreased with a commercially available degreasing agent (registered trademark FINECLINA-1 340, manufactured by Nippon Parkerizing Co., Ltd.) at a concentration of 20 g / L, a temperature of 60 ° C, and an immersion time of 10 minutes. It was treated and immersed and washed in tap water at 60 ° C for 30 seconds. Next, each material was immersed in the above-mentioned treatment liquids 1 to 5 at 60 ° C for 10 seconds, pulled up, and sprayed with hot air at 80 ° C for 3 minutes while the liquid was still attached, and dried. I let it.

Comparative Examples 1-2

The above-mentioned material was degreased and washed with water in the same manner as in Examples 1 to 5, and then treated in the same manner as in Examples 1 to 5 using the above-mentioned treatment solutions 6 and 7.

Comparative Example 3

The above-mentioned material was degreased and washed with water in the same manner as in Examples 1 to 5. Then, the substrate was immersed in the above-mentioned treatment solution 1 at 60 ° C for 10 seconds, pulled up, and air blown (air pressure: 3 Kgf / cm ² ) to sufficiently drain the solution. Sprayed for minutes and dried.

The total thickness of the lubricating film, the thickness of the base layer, and the thickness of the lubricant layer were measured for the test pieces of the materials of Examples 1 to 5 and Comparative Examples 1 to 3 by the method described below. Method, posterior drill test and spike test Was done. Table 1 shows the results of this measurement and test.

As is clear from Table 1, it is understood that Examples 1 to 5 according to the method for producing a metal material for plastic working of the present invention exhibit excellent lubricity. Comparative Example 1, in which the lubricant layer thickness and the lubricant layer / base layer ratio were out of the range of the present invention, was inferior in lubricity. In particular, the spike test resulted in seizure of the mold and could not be formed. Comparative Example 2 in which the thickness of the base layer and the ratio of the lubricant layer / base layer were out of the range of the present invention was also inferior in lubricity. Further, Comparative Example 3, in which the thicknesses of the base layer and the lubricant layer were out of the range of the present invention, was also inferior in lubricity.

Measurement and test method

(1) Measurement method of total film thickness, pace layer thickness and lubricant layer thickness Using a commercially available EPMA (8705 L type manufactured by Shimadzu Corporation), the base layer and The thickness of the lubricant layer was measured. In the measurement, the representative elements were P and C for treatment solutions 1 and 2, K and C for treatment solution 3, K and F for treatment solution 4, and Na and C for treatment solution 5. The measurement was performed five times with different parts, and the average value was shown.

(2) Rear drilling test method (see Fig. 1) One set of the above-mentioned cylindrical rear perforated test piece shown in (A) of FIG. 1 was sequentially formed by a die and a punch of a 200-ton crank press shown in (B) of FIG. Make a cup-shaped molded product of C). In forming, it is processing with 50% reduction in area, leaving 10mm. The height in the cup of the test piece with no scratches on the inner surface shall be the good drilling depth (mm). Here, it is assumed that the performance of the sample prepared by the conventional chemical reaction Z-stone treatment is 56 mm or more. The die is SKD11, the punch is HAP40, the land diameter is 2.2.1 mm, and the machining speed is 30 strokes / min.

(3) Spike test method (see Fig. 2)

The spike test was performed in accordance with the method described in JP-A-5-79669. As shown in FIG. 2 (a), the columnar spike test piece 2 is placed on a die 2 having a mouth-like inner surface shape, and then a test is performed by applying a load via a plate 3. The specimen is pushed into the die and formed into the shape of the processed specimen shown in Fig. 2 (b). In this way, a spike according to the die shape was formed, and the lubricity was evaluated based on the spike height (mm) at this time. Therefore, the higher the height, the better the lubricity. Here, 13.0 mm or more, which is the performance of the sample prepared by the conventional chemical reaction / stone treatment, is evaluated as good. Industrial applicability

As is clear from the above description, the use of the metal material for plastic working and the method for producing the same according to the present invention can produce a film having high lubricity by simple processing, and also generate industrial waste. Since it has no impact on the environment and has little impact on the environment, its industrial utility value is extremely high.

Claims

The scope of the claims

1. A metal material for plastic working provided with an inclined two-layer lubricating film consisting of a base layer and a lubricant layer on the surface, wherein the pace layer has a thickness of 0.1 to 15. A lubricant layer having a thickness of 0.1 to 10.0 m and located on the surface side, and a lubricant layer Z-based. A metal material for plastic working, wherein a layer thickness ratio of the layers is 0.2 to 3.0.

2. The plastic working according to claim 1, wherein the inorganic compound is at least one selected from the group consisting of phosphates, sulfates, borates, silicates, molybdates, and ungstenates. For metal material.

3. The metal material for plastic working according to claim 1, wherein the lubricant is at least one selected from the group consisting of metal stone, wax, polytetrafluoroethylene, molybdenum disulfide and graphite.

4-Any of claims 1 to 3, wherein the metal material is iron, steel, stainless steel, aluminum, aluminum alloy, magnesium, magnesium alloy, titanium, titanium alloy, copper, copper alloy, tin, tin alloy. Or the metal material for plastic working according to item 1.

5. An aqueous treatment liquid containing an inorganic compound and a lubricant as a main component is brought into contact with the surface of the metal material, and then dried, so that a thickness of the inorganic compound as a main component on the interface side with the metal is 0.1 to 0.1. A base layer of 15 zm is located, and a lubricant layer containing a lubricant as a main component of 0.1 to 10 / m is located on the surface side, and the layer thickness ratio of the lubricant layer / base layer is 0. A method for producing a metal material for plastic working, characterized by forming an inclined two-layer lubricating film of 2-3.