JPH11222599A - Lubricating coating film for metal plastic working - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having excellent lubricating properties, not causing environmental pollution and not causing rusting by incorporating an alkali metal or alkaline earth metal carbonate and a binder. SOLUTION: An alkaline earth metal carbonate such as calcium carbonate or magnesium carbonate is mixed with a binder being a metasilicate such as sodium metasilicate. The amount of the binder used is 25-150 pts.wt., desirably, 25-125 pts.wt. per 100 pts.wt. carbonate. The lubricating coating agent can be applied in the form of an aqueous solution or dispersion, so that a chlorine- containing or fluorine-containing solvent need not be used. Further, even when an auxiliary lubricant is used in the plastic working of a metal, the coating film of the carbonate is desirable as a carrier which carries the auxiliary lubricant. In use, the lubricating coating agent is added to water to prepare a vat bath. The concentration of the carbonate in the vat bath is desirably 5-40 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal used for plastic working, such as drawing, drawing, punching, and forging, of a metal material to be processed such as stainless steel, high carbon steel, titanium steel and its alloy steel. The present invention relates to a lubricating coating agent for plastic working.

[0002]

2. Description of the Related Art Metal forming such as wire drawing or wire drawing is performed by drawing a metal material such as a wire or a rod through a die to obtain a product having a desired shape and dimensions, and drawing by drawing a wire through a die. In this case, since the metal material and the die are baked when they come into direct contact with each other, the processing is performed with a lubricant interposed therebetween. Since such a lubricant has the advantages of improving workability and extending the life of a die in addition to preventing seizure, a lubricating treatment is always performed especially in processing difficult-to-machine materials.

[0003] In many cases, a lubricant is formed of a lubricating film forming a film on the surface of a metal material such as a wire, and an auxiliary lubricant (such as calcium stearate or sodium stearate) used in a die box immediately before a die. Dry lubricants mainly composed of metal soaps, chlorinated oils, and wet lubricants using sulfated oils). The lubricating coating agent imparts lubricity to the metal material and serves as a carrier for drawing the auxiliary lubricant into the die.

[0004] Representative examples of such lubricant coating agents are shown below. (1) Lime soap (2) Phosphates, especially zinc phosphate (3) Oxalates (4) Chlorine or fluororesins (5) Inorganic salts, especially borax for iron and stainless steel, sulfuric acid for stainless steel potassium

[0005]

The lime soap of the above (1) is used in the form of an aqueous dispersion of calcium hydroxide and metal soap, and a metal agent is immersed in this dispersion and dried to form a lubricating film. Is formed. However, the lime soap film has insufficient lubricity, and further involves the generation of dust during processing and transport of the film treating agent, thus causing a problem that the working environment is deteriorated.

The above phosphate (2) is most commonly used as an iron-based lubricating coating for plastic working. However, it requires time and effort in liquid management and requires measures against phosphorus during wastewater treatment. Insufficient wastewater treatment leads to eutrophication of rivers.
Further, the phosphate coating has a serious problem of phosphorus immersion which causes delayed fracture of high tension bolts.
The oxalate of (3) above is well known as a coating agent for plastic working of stainless steel.However, oxalate is a harmful substance and requires careful handling, and hexavalent chromium is discharged into wastewater. Wastewater treatment problems arise. Further, after the oxalic acid film treatment, if the coated material is left in a high humidity atmosphere for a long time, rust may be generated.

The chlorine-based resin or the fluorine-based resin of the above (4) forms a lubricating resin film on the surface of a metal material. Solvents such as fluorotrichloroethane, trichlene, perchrene, 1,1,1-trichloroethane, and methylene chloride are used in large amounts. Therefore, there are problems in working environment, groundwater pollution, air pollution, and ozone layer destruction due to the use of fluorocarbon solvents.
Therefore, their use is restricted by laws and regulations.

Since the inorganic salt of the above (5) is water-soluble or water-dispersible, water can be used as a solvent.
There is an advantage that the above problem does not occur. However, among the above-mentioned inorganic salts, borax has a problem that since the film after drying has high hygroscopicity, the film crystallizes due to moisture absorption, and the performance as a carrier for the auxiliary lubricant is reduced. On the other hand, since potassium sulfate is a sulfate, chromium-based stainless steel has a problem that rust is generated by the coating treatment. In addition, since the potassium sulfate film is relatively hard, there is also a problem that a so-called indentation phenomenon occurs in which the film is embedded in the surface of the metal material to be processed by the pressure during plastic working.

[0009] In addition, graphite and molybdenum-based lubricating coating agents are known in addition to the above. However, graphite may cause generation of dust and dirt on workers, and molybdenum-based coating agents are expensive. There is a problem that there is. Accordingly, an object of the present invention is to provide a lubricating coating agent for metal plastic working which does not cause environmental pollution, does not cause rust, is easy to handle, and has excellent lubricity.

[0010]

Means for Solving the Problems The inventor of the present invention has conducted intensive studies to solve the above-mentioned problems, and as a result, the use of a carbonate which has not been used as a lubricating coating agent until now has the surface of a metal material. As a result, the present inventors have found the surprising fact that a lubricating film having excellent lubricating properties can be obtained, thereby completing the present invention. The carbonate does not cause rust on the metal material unlike conventional potassium sulfate, and can be used by dissolving or dispersing in water. Therefore, a chlorine-based or fluorine-based solvent such as a conventional resin coating agent is used. Therefore, there is no risk of environmental pollution, easy handling, and no risk of dust generation.

The above-mentioned carbonate coating is also suitable as a carrier for supporting the auxiliary lubricant when an auxiliary lubricant is used during plastic working of metal. Furthermore, since the carbonate coating in the present invention is relatively soft, there is no occurrence of the indentation phenomenon that occurs when conventional potassium sulfate is used.

That is, the lubricating coating agent for metal plastic working of the present invention is characterized by containing a carbonate of an alkali metal or an alkaline earth metal and a binder agent. The binder is used to increase the strength of the carbonate film. As such a binder, it is preferable to use a metasilicate.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The lubricating coating agent for metal plastic working of the present invention contains, as described above, a carbonate of an alkali metal or an aryl earth metal and a binder as main components.
Examples of the alkali metal carbonate include lithium carbonate,
Sodium carbonate, sodium bicarbonate, potassium carbonate,
And potassium hydrogen carbonate. Examples of the alkaline earth metal carbonate include beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate. In the present invention, only one of these carbonates may be used, or two or more thereof may be used in combination. Further, in the present invention, a carbonate other than an alkali metal or alkaline earth metal carbonate can be used in combination, if necessary. Examples of such a carbonate include manganese carbonate, iron carbonate, ammonium carbonate, ammonium hydrogen carbonate and the like.

In the present invention, it is particularly preferred to use carbonates of alkaline earth metals such as calcium carbonate and magnesium carbonate from the viewpoints of lubricity, workability, handleability, rust prevention, environmental pollution prevention and the like. As calcium carbonate, both heavy calcium carbonate obtained by pulverizing limestone and synthesized precipitated calcium carbonate (light calcium carbonate) can be used.

As the above-mentioned binder agent, for example, metasilicate (a salt of an alkali metal such as sodium, an alkaline earth metal, a transition metal or the like) is preferably used. Further, instead of or together with metasilicate, sodium silicate (water glass), a water-soluble or water-dispersible resin such as a melamine resin, a phenol resin, an acrylic resin, etc., and glue, konjac paste , Brown sugar or the like may be used as a binder agent.

The above-mentioned binder agent has functions of imparting ductility to the carbonate, facilitating the formation of the carbonate film at the time of film formation, increasing the strength of the formed film, and improving the peeling resistance. . These binders are preferably water-soluble or water-dispersible, but even if the binder itself is not water-soluble or water-dispersible, for example, it can be uniformly dispersed in water by using in combination with a surfactant or the like. Can be.

The amount of the binder is appropriately determined depending on the type of the carbonate and the binder used. Usually, the binder is used in an amount of 25 to 150 parts by weight, preferably 25 to 150 parts by weight, per 100 parts by weight of the carbonate. It is preferable to mix in a proportion of 125 parts by weight. If the amount of the binder agent is less than the above range, peeling of the coating may occur. On the other hand, when the amount of the binder agent is more than the above range, the resulting coating film may be hard and may have poor lubricity.

In order to form a lubricating film on the surface of a workpiece using the lubricating film agent of the present invention, first, the lubricating film agent of the present invention containing predetermined amounts of the above-mentioned carbonate and binder is added to water. To prepare a bath solution. At this time, the concentration of the carbonate in the construction bath solution is suitably 5 to 40% by weight, preferably 5 to 35% by weight, more preferably 5 to 25% by weight.

In addition to the above-mentioned carbonates and binders, surfactants, other lubricants (molybdenum disulfide, graphite, lime, etc.), pH adjusters (aqueous ammonia, amines, etc.) are contained in the construction bath liquid. Additives such as thickeners can be added as needed. The prepared bath solution is
The solid content concentration is preferably 20% by weight or less, and more preferably 6 to 15% by weight. If the solid content concentration is higher than that, the viscosity becomes too high, so that the formation of a film on the surface of the workpiece is hindered. May cause damage.

The method for forming a lubricating coating mainly includes an immersion method and an in-line method, and the lubricating coating agent of the present invention can be applied to either method. In either case, the lubricating film is formed by immersing the work material in the construction bath solution or applying the construction bath solution to the surface of the work material and then drying it. Here, the immersion method refers to a method of immersing a workpiece one by one in a construction bath liquid. The in-line method is a method in which a continuous long work material such as a wire rod is continuously guided into a building bath, immersed or coated, and further dried and plastically processed (drawing work or the like) is continuously performed.

The above-mentioned bath solution may be used at room temperature. In this case, it is desirable to preheat the work material to about 100 ° C. in advance. Generally, the bath solution is about 80-9.
It is preferable to use while stirring at a temperature of 0 ° C. Then, the work material is immersed in the heated building bath solution for about 5 to 15 minutes, and then pulled up, whereby the moisture attached to the surface of the work material is quickly volatilized to obtain a dry film. be able to.

On the other hand, when the material to be processed is small, small, or thin, the drying property after the immersion treatment is poor. Therefore, it is preferable to provide forced drying means such as hot air drying. In particular, in the case of in-line lubricating coating treatment, it is preferable to provide forced drying means in order to accelerate drying.

The material to be lubricated by using the lubricating coating agent of the present invention is not particularly limited, and may be any of various stainless steels, steels, titanium steels, aluminum steels, and alloy steels thereof. Is also applicable,
Particularly, it is suitable for plastic working of stainless steel, high carbon steel, titanium steel, etc., which are called difficult-to-work materials requiring high lubricity during working.

The workpiece on which the lubricating film is formed as described above is used for plastic working such as drawing, drawing, punching, and forging. At this time, the work material on which the lubricating film has been formed may be used as it is for plastic working, but especially in the case of difficult-to-work materials, an auxiliary lubricant placed in the die box immediately before the die adheres to the surface. It is sent to the dice. As the auxiliary lubricant, for example, a dry lubricant mainly containing a metal soap made of a higher fatty acid salt such as calcium stearate is mainly used.

In the present invention, since the carbonate is in intimate contact with the surface of the workpiece in the form of an amorphous crystal, the surface is uneven, and the auxiliary lubricant is held in the concave portion. For this reason, the auxiliary lubricant is excellent in holding property at the time of processing, so that there is an advantage that the workability is improved and the life of the die is prolonged.

【Example】

Hereinafter, the lubricating coating agent of the present invention will be described in detail with reference to examples. Examples 1 to 5 Calcium carbonate and sodium metasilicate were mixed at predetermined ratios shown in Table 1 below to prepare lubricating coating agents. This lubricating coating agent was dissolved in 4 times the amount of water to obtain a bath solution.

[0027]

[Table 1]

Comparative Example 1 Chlorine-based resin (“No.
C)) was used as a lubricating coating agent, which was dissolved in methylene chloride to a concentration of 30% by weight to obtain a building bath solution.

Comparative Example 2 Potassium sulfate was used as a lubricating coating agent, and
It was dissolved to a concentration of 5% by weight to obtain a bath solution. Comparative Example 3 Calcium hydroxide and a metal soap (calcium stearate and oil fatty acid) were dispersed in water to obtain a lime soap having a total solid content of 25% by weight.

Comparative Example 4 An oxalate was dissolved in water to a concentration of 20% by weight.
A bath solution was obtained. Comparative Example 5 A crystalline borax powder was dissolved in water to a concentration of 15% by weight to obtain a bath solution.

Comparative Example 6 Zinc phosphate was dissolved in water to a concentration of 20% by weight to obtain a bath solution. Test Example A lubricating coating was formed using each of the bath solutions obtained in the above Examples and Comparative Examples, and the lubricity was evaluated. The test method is as follows.

While the building bath solution was heated to 85 ° C. and stirred, a stainless steel pipe of SUS304 (surface gloss finish, outer diameter 22 mm, inner diameter 19 mm, thickness 1.5 m) was added thereto.
m, having a length of 45 mm and an upper end of about 5 mm having a shape of being pushed outward in a trumpet shape) for 5 minutes. The stainless steel pipe was preheated to 90 ° C in advance. After immersion, the stainless steel pipe was pulled out of the bath and dried in that state to obtain a lubricating coating.

Then, after applying a low-viscosity chlorinated oil as an auxiliary lubricant to the lubricating film, a stainless steel pipe is inserted into a hole formed in a metal block, and the upper end of the trumpet is spread out in a trumpet shape. Locked around the entrance edge. The metal block has a height of 75 mm, and the hole has a diameter of 23.50 mm at the entrance on the upper surface, is tapered to a depth of 45 mm from the entrance, and has an inner diameter of 2 mm at a depth of 45 mm.
2.10 mm. The hole has a uniform diameter from the depth of 45 mm to the outlet.

In this state, a steel ball having a diameter of 20.6 mm is pushed into the pipe by applying a load of 10 tons from the upper end of the stainless steel pipe, and is forcibly passed through the pipe. This is comparable to drawing, and the processing rate calculated from the change in the thickness of the lower end of the pipe before and after passing the steel ball is about 48%. Observe the inner surface of the pipe after the steel ball has passed and the contact surface of the steel ball with the naked eye and a loupe with a magnification of 5 times,
The lubricity of the lubricating coating was evaluated on the basis of the following five steps in consideration of the state during processing and the like.

XX: The steel ball stopped moving in the middle of pushing with a load of 10 tons, and it was impossible to push further. ×: The pipe could not withstand the indentation load, the pipe was broken on the way, and many scratches occurred on the steel balls and the inner surface of the pipe. Δ: Many flaws were generated on the inner surfaces of steel balls and pipes during processing and were not practical. : Slight flaws were observed on the inner surface of the steel ball or pipe, and practical use was possible. ◎: Almost no flaw was observed. Table 2 shows the test results.

[0036]

[Table 2]

From Table 2, it can be seen that the lubricating coatings composed of calcium carbonate and metasilicate used in Examples 1 to 5 have lubricity equal to or higher than the lubricating coatings of Comparative Examples. I understand.

Of the comparative examples, the comparative example 1 provided the best results, but it was difficult to use it because it used a chlorine-based solvent and had problems such as air pollution. Also,
When SUS430 and SUS410 stainless steel coated with potassium sulfate of Comparative Example 2 were allowed to stand at room temperature for 10 days, rust was generated on the coated portion. Furthermore, since the oxalate of Comparative Example 4 was a deleterious substance, it was difficult to handle the oxalate, and there was a problem that the wastewater contained hexavalent chromium.

Examples 6 to 10 Examples 1 to 5 were repeated, except that the respective binders shown in Table 3 were used in the amounts shown in Table 3 in place of sodium metasilicate.
A bath solution (solid content: 20% by weight) was prepared in the same manner as described above, and a lubricating coating evaluation test was performed using this in the same manner as in the above Test Example. Table 3 shows the results.

[0040]

[Table 3]

From Table 3, it can be seen that high lubricity was obtained when a binder other than sodium metasilicate was used. Examples 11 to 14 The construction bath solution (20 parts by weight of carbonate, 20 parts by weight of sodium metasilicate and 160 parts by weight of water) in the same manner as in Example 3 except that the carbonates shown in Table 4 were used instead of calcium carbonate. , A solid content concentration: 20% by weight), and using this, an evaluation test of the lubricating coating was performed in the same manner as in the above Test Example. Table 4 shows the results.

[0042]

[Table 4]

From Table 4, it can be seen that high lubricity was obtained also when a carbonate other than calcium carbonate was used.

[0044]

As described above, since the lubricating coating agent for metal plastic working of the present invention contains an alkali metal or alkaline earth metal carbonate and a binder, it does not cause environmental pollution, and There is an effect that no rust is generated on the workpiece, the handling is easy, and the lubricating property is excellent. Therefore, the lubricating coating agent of the present invention can be suitably used for various metal plastic workings of difficult-to-machine materials and the like.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10N 40:24

Claims (3)

[Claims] 1. A lubricating coating agent for metal plastic working comprising an alkali metal or alkaline earth metal carbonate and a binder agent. 2. The lubricating coating agent for metal plastic working according to claim 1, wherein the carbonate is a carbonate of an alkaline earth metal. 3. The lubricating coating agent for metal plastic working according to claim 1, wherein said binder agent is a metasilicate.