JPH10316990A - Water-base lubricant for metal plastic working - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricant which exhibits a good lubricity when applied to a metal mold and does not cause sticking to the mold, underfilling, and deposition on the mold by incorporating an aldonate having a specific chemical structure into a water-base lubricant for metal plastic working contg. an alkali salt of a polycarboxylic acid. SOLUTION: The joint use of an alkali salt of a low-molecular polycarboxylic acid and an alkali salt of a high-molecular polycarboxylic acid is pref. Examples of the high-molecular polycarboxylic acid are a maleic acid copolymer and polyacrylic acid. The content of the salt in the aq. soln. is 1-15%. The aldonate used is one which has 4-8 carbon atoms and is a salt of a group 2 element. The content of the aldonate in the aq. soln. is 0.1-40%. A pref. example of the aldonate is calcium gluconate. If necessary, a water-soluble high-molecular compd. may be added as a mold sticking agent. The total content of ingredients in the lubricant is 2.0-75%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous lubricant for metal plastic working (hereinafter, simply referred to as "aqueous lubricant").

[0002] Here, plastic working includes forging, press working,
Although spinning, rolling, rolling, extrusion and drawing are included, the aqueous lubricant of the present invention is particularly suitable for forging.

[0003]

2. Description of the Related Art In recent years, various water-based lubricants containing an alkali salt of a polycarboxylic acid and containing no graphite, which is non-staining and free from smoke or inflammation, have been proposed in place of oil-based lubricants. .

For example, there are lubricants using an alkali salt of fumaric acid (JP-A-58-52935) and lubricants using an alkali salt of phthalic acid (JP-A-58-84898).

[0005] These lubricants are said to be inferior in lubricity, film formation, heat resistance and the like as compared with the graphite-based aqueous lubricant (see the section of "Prior Art" in JP-A-1-299896). ).

In view of the above, Japanese Patent Application Laid-Open No. 1-299896 proposes an aqueous lubricant having the following structure.

A composition processing water comprising an aqueous composition containing 0.1 to 30% by weight of a mixture of an alkali salt of fumaric acid and an adipic acid and 0.01 to 20% by weight of a water-soluble polymer compound. Soluble lubricant. "

[0008]

However, as a result of a follow-up test conducted by the present inventors, the aqueous lubricant has no problem in forming a lubricating film, but has a problem in lubricating performance (especially in a high-temperature atmosphere). ), It turns out that it is not always enough.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide an aqueous lubricant for metal plastic working with enhanced lubrication performance.

[0010]

An aqueous lubricant for metal plastic working according to the present invention is used for metal plastic working.
An aqueous lubricant containing an alkali salt of a polycarboxylic acid, which further comprises, in addition to the alkali salt of a polycarboxylic acid, an aldonic acid group 2 salt having 4 to 8 carbon atoms as an essential component. Things.

[0011]

DETAILED DESCRIPTION OF THE STRUCTURE In the following description, the weight unit is a weight unit unless otherwise specified.

(1) The aqueous lubricant for metal plastic working according to the present invention is used at the time of metal plastic working and presupposes that it contains an alkali salt of polycarboxylic acid.

Here, the polycarboxylic acid alkali salt includes a low molecular weight polycarboxylic acid alkali salt and a high molecular weight polycarboxylic acid alkali salt. However, in general, from the viewpoints of heat resistance and mold adhesion, the low molecular weight polycarboxylic acid alkali salt is preferable. It is desirable to use an acid alkali salt and a high molecular weight polycarboxylic acid alkali salt in combination (see JP-A-6-212184 / 8-157860).

As the alkali salt, a sodium salt, a potassium salt, and a lithium salt can be preferably used, and a sodium salt is particularly preferable.

(I) Examples of the alkali salt of a low-molecular polycarboxylic acid include the above-mentioned alkali salts of aliphatic saturated and unsaturated dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, malic acid, and fumaric acid. Alkali salts of aromatic polycarboxylic acids such as phthalic acid, terephthalic acid and trimellitic acid can be used.

It is desirable to use a low molecular weight polycarboxylic acid alkali salt in combination, and particularly preferable to use an unsaturated / saturated dicarboxylic acid salt in combination. For example, it is used in combination with an alkali salt of fumaric acid and an alkali salt of adipic acid.

The mixing ratio of each alkali salt of fumaric acid and adipic acid is usually the former / the latter = 2/8 to 8/2 (preferably 4/6 to 6/4), and the aqueous solution of both is used. The total content of the composition is 0.1 to 40% (preferably 0.5 to
20%).

If the content of the unsaturated or saturated alkali carboxylic acid is too large or too small, it is difficult to obtain practical lubricating performance and mold releasing performance. Further, if the total content of both alkali salts at the time of dilution is too small, the adhesion between the aqueous lubricant and the high-temperature mold is reduced, and a uniform lubricating film cannot be obtained. This may cause galling, cracking and the like. On the other hand, if the amount is excessive, stickiness and accumulation may occur around the mold.

(Ii) Examples of the alkali salt of a high molecular weight polycarboxylic acid include an alkali salt of a maleic acid copolymer and an alkali salt of a polyacrylic acid. Among these, the maleic acid copolymer alkali salt increases the viscosity of the diluent,
It is desirable because it has an effect of improving heat resistance and mold adhesion.

The content of the alkali salt of a high molecular weight polycarboxylic acid is 1 to 15% (preferably 2 to 15%) in the aqueous solution composition.
10%).

If the content of the alkali salt of the high molecular weight polycarboxylic acid is too small, the viscosity of the aqueous lubricant is low,
If the temperature is higher than the above, the adhesion to the mold becomes poor, and if it is excessive, the viscosity of the aqueous lubricant becomes too high, and the handling properties such as coating workability deteriorate, which is not preferable in use.

Examples of the usable maleic acid copolymer include:
Examples thereof include an isobutylene / maleic acid copolymer, a styrene / maleic acid copolymer, and a vinyl ethyl ether / maleic acid copolymer. An isobutylene / maleic acid copolymer can be preferably used.

(2) The above-mentioned aqueous lubricant is characterized in that, in addition to the alkali salt of polycarboxylic acid, an aldonic acid group 2 salt having 4 to 8 carbon atoms as an essential component is further contained as an essential component.

The aldonic acid group 2 salt of the periodic table has an effect of increasing lubricity.

The aldonic acid is not particularly limited as long as it has 4 to 8 carbon atoms, but gluconic acid is preferred. Here, a magnesium salt, a calcium salt, a barium salt, or the like can be suitably used as the Group 2 salt of the periodic table, but a calcium salt is particularly preferable.

The content of the aldonic acid group 2 salt of the periodic table is as follows:
0.1 to 40% (preferably 0.5 to 2%) in aqueous solution composition
0%).

(3) Further, in the above-mentioned aqueous lubricant, 10
In order to ensure the adhesion to the mold at about 0 ° C., in addition to the above-mentioned alkali salt of polycarboxylic acid and aldonic acid group 2 salt of aldonic acid having 4 to 8 carbon atoms, if necessary, a water-soluble polymer compound is added. It may be added as a mold adhesive.

Examples of water-soluble polymer compounds that can be used include:
Polyacrylamide, hydroxyethyl cellulose,
Examples thereof include carboxymethyl cellulose, ammonium polycarboxylate, and polyvinyl alcohol.
At this time, polyacrylamide is desirable because it also has an effect of increasing lubricity.

The amount of the water-soluble polymer to be added is usually 0.01 to 5% (preferably 0.02 to 2%) in an aqueous solution composition.
%).

(4) The method for preparing the aqueous lubricant of the present invention does not require a special device or a special method, and the above-mentioned components and water are sufficiently mixed at room temperature and pressure in a suitable container. It can be prepared by mixing. Normal,
The total content of each drug should be approximately 2.0-75% aqueous solution.

In the above preparation, the mixture may be supplied in the form of an alkali salt and mixed. However, usually, the mixture is supplied and mixed in the form of each dibasic acid and alkali hydroxide. Alkali hydroxide is
Slightly larger supply than the total equivalent of dibasic acid.

When this aqueous lubricant is used, it may be used as a stock solution, but it is usually appropriately diluted 2 to 20 times with water and applied to a mold by spraying or brushing.

[0033]

EXAMPLES The formulations shown in Table 1 were blended in respective amounts and mixed well at room temperature to obtain Examples 1-2 and Comparative Examples 1-3 and Conventional Examples 1-2.

(1) Examples prepared by the above method, comparative examples,
With respect to the conventional example, the friction coefficient was determined by a ring compression experiment.

The upper and lower sides of a mold (SKD61) of φ100 × 50 mm are heated to about 200 ° C., and 15 mL of a 10-fold diluted aqueous lubricant material is spray-coated on the contact surface of the upper and lower molds with the ring (air pressure: 0.1 mm). 39MPa (4kg / cm ² )
I do. On the other hand, a φ30 × φ15 × 10 mm ring (S45
C material) is heated to 1100 ° C. in an electric furnace.

Using a 100-ton mechanical press, the reduction rate (working degree) of the height of the mold and the ring and the rate of change of the inner diameter are determined by the “energy method by Kudo” (Proc. 5th. Japan Nat.C.
The coefficient of friction was determined by plotting on a theoretical curve determined by ong. Appl. Mech. (1955), 75). Table 1 shows the respective friction coefficients.

The results shown in Table 1 show that Conventional Examples 1 and 2 were based on a combination of sodium fumarate and sodium adipic acid, and to which hydroxyethyl cellulose was added as a water-soluble polymer compound (adhesive). Compared to Comparative Examples 1 to 3 in which sodium polyacrylate and sodium salt of maleic acid copolymer were added to the above base, sodium salt of maleic acid copolymer and calcium gluconate (Aldonic acid Periodic Table 2 salt) It can be seen that each of the examples of the present invention containing the combination of (1) and (2) has a low coefficient of friction. Furthermore, it can be seen that Example 1 in which polyacrylamide was added as the water-soluble polymer compound had a further reduced coefficient of friction as compared to Example 2 in which sodium polyacrylate was used.

[0038]

[Table 1]

(2) Next, a test was conducted using the actual machine of the embodiment.

The aqueous lubricant of Example 1 was diluted 20-fold with water, spray-applied to a forging die heated to about 100 to 300 ° C. by a 2500 t mechanical press, and sprayed to about 1100 to 1
Hot forging (product weight: 810 g × 2 open type) of the S30L material heated to 200 ° C. was performed. About 1000
Even if 0 pieces were forged, there was no cracking, no underfill, no accumulation on the mold, and good results were obtained.

Similarly, the aqueous lubricant of Example 1 was
Diluted by a factor of 1, and with a 1600t mechanical press, about 100-3
Spray-applied to a forging die heated to 00 ° C.
The material of S45 heated to 00 to 1200 ° C. was subjected to hot forging (product weight: 1200 g closed type). About 10
Even forging 2,000 pieces, there was no cracking, no underfill, no accumulation on the mold, and good results were obtained.

Similarly, the aqueous lubricant of Example 2 was added to 160
Spray-applied to a forging die heated to about 100 to 350 ° C. by a 0t mechanical press to hot forge the SCR20 material heated to about 1100 to 1200 ° C. (product weight: 8
50 g closed type). Even when about 7,000 pieces were forged, there was no cracking, no underfill, and no accumulation on the mold, and good results were obtained.

[0043]

The aqueous lubricant of the present invention has the following structure, in addition to the alkali salt of a polycarboxylic acid, further comprising an aldonic acid group 2 salt having 4 to 8 carbon atoms as an essential component. It works.

As shown in the above examples, the low-molecular-weight polycarboxylic acid of the prior art in which a water-soluble high-molecular compound was added to a low-molecular-weight polycarboxylic acid was used.
Compared to each aqueous lubricant of Comparative Example using a high-molecular polycarboxylate, the coefficient of friction is kept small,
There is no coating deposition on the mold.

That is, when the aqueous lubricant of the present invention is used after being applied to a mold, the lubricating performance is good, there is no sharpness or underfill in the mold, and further, deposition on the mold occurs. Nothing.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10N 10:02 30:06 40:24 40:36

Claims (7)

[Claims] 1. An aqueous lubricant containing an alkali salt of a polycarboxylic acid, which is used in metal plastic working, and further comprises an aldonic acid having 4 to 8 carbon atoms in addition to the alkali salt of a polycarboxylic acid. An aqueous lubricant for metal plastic working, comprising a group III salt as an essential component. 2. The aqueous lubricant for metal plastic working according to claim 1, wherein the aldonic acid group 2 salt of the periodic table is calcium gluconate. 3. The metal plastic working machine according to claim 1, wherein the polycarboxylic acid alkali salt is a combination of a low molecular weight polycarboxylic acid alkali salt and a high molecular weight polycarboxylic acid alkali salt. Aqueous lubricant. 4. The method according to claim 3, wherein the low molecular weight dicarboxylic acid alkali salt is a combined system of fumaric acid and adipic acid alkali salt, and the high molecular weight polycarboxylic acid alkali salt is a maleic acid copolymer alkali salt. An aqueous lubricant for metal plastic working characterized by the fact that: 5. The method according to claim 4, wherein the alkali salt of the dicarboxylic acid: 0.1 to 30 wt%, the alkali salt of the maleic acid copolymer: 1 to 15 wt%, and the aldonic acid Group 2 salt of the periodic table: 0.1 to Aqueous lubricant for metal plastic working characterized by having an aqueous solution composition of 30 wt% 6. The metal according to claim 5, wherein the mixing ratio of the alkali dicarboxylate to the alkali fumarate and the alkali adipic acid salt is the former / the latter = 2/8 to 8/2. Aqueous lubricant for plastic working. 7. The aqueous lubricant for metal plastic working according to claim 1, wherein polyacrylamide is further added for increasing lubricity.