JPH10330776A - Lubricant composition and working method for isothermal forging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricant compsn. for isothermal forging which provides good lubrication effect and releasability by a lubrication treatment not based on a precoating method and enables continuous isothermal forging even in the case of a large-size work and/or a high working ratio and to provide a working method using the same. SOLUTION: A lubricant compsn. contg. a nickel powder and at least either an ammonium borate or an amine borate in a wt. ratio of (10:90)-(90:10) is mixed with water to give a liq. mixture with a concn. of 20-80 wt.%. The mixture is sprayed to at least either a material to be worked or a metal mold heated to 500-1,000 deg.C before isothermal forging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of applying a titanium alloy to a mold and a material at the time of isothermal forging, thereby reducing the coefficient of friction, facilitating the working and preventing seizure. TECHNICAL FIELD The present invention relates to a lubricating composition for constant temperature forging, which can facilitate release from a mold, and a processing method by constant temperature forging using the lubricant composition.

[0002]

2. Description of the Related Art A constant temperature forging process is a die forging process performed while maintaining a mold and a material to be processed at the same temperature, and is used for forming difficult-to-process materials such as titanium alloys and nickel-based alloys. The pressurization of the mold is usually performed by applying a constant high pressure for a long time by hydraulic means.

For example, in isothermal forging of a β-type titanium alloy, a mold and a material to be processed are heated to the same temperature in the range of 700 to 950 ° C., and the mold containing the material to be processed is heated for 30 to 60 minutes. The molding is performed by pressing.

[0004] In constant temperature forging, a lubricant is usually applied to both the mold and the material to be processed in order to reduce the coefficient of friction between the mold and the material and to facilitate release from the mold. I do. As a conventional lubrication method, a so-called pre-coat method is adopted in which a lubricant composition is previously applied to a mold and a material to be processed before they are heated to a predetermined forging temperature to form a lubricating film.

[0005] The lubricant used in this precoating method is
As disclosed in Japanese Patent Application Laid-Open No. 54-1111056, it is composed of a mixture of a glass component that melts at the forging temperature and a high hardness (Mohs hardness of 5.5 or more) inorganic abrasive component that does not melt at the forging temperature. As the inorganic abrasive component, carbide,
Synthetic materials such as oxides and nitrides and natural minerals can be used. It is also known to use a solid lubricant, such as boron nitride or graphite, with a glass component instead of an inorganic abrasive.

[0006] In order to form a lubricating film using this mixture, a coating liquid is prepared by dispersing each powder of a glass component and an abrasive component in an organic solvent solution of an organic polymer. This coating liquid is applied to the mold and the material to be processed, heated and dried (solvent removal) as necessary, and a lubricating film containing the glass component and the abrasive component powder in the organic polymer is obtained. Is formed.

At the time of forging, the die on which the lubricating film is formed and the material to be processed are first preheated, and the organic polymer is eliminated by thermal decomposition. Thereafter, the mold and the material to be processed are set in a hydraulic press, heated to a predetermined forging temperature, and then pressurized. At the forging temperature, the glass component is in a molten state, and a lubricating effect (friction coefficient reduction effect) is achieved by interposing a liquid lubricating film in which the inorganic abrasive component is dispersed in the glass melt between the mold and the workpiece. Be demonstrated. After release and cooling, the glass adhered to the molded body is removed by shot blasting or pickling.

[0008]

When constant temperature forging is performed by employing lubrication by the precoating method, the mold must be cooled each time it is used, and the working efficiency is greatly reduced. Further, a drying step of the applied lubricant composition and a preheating step for eliminating the organic polymer before forging are required, and the number of steps is increased. In addition, the lubricating film may peel off during transport of the work material on which the lubricating film has been formed in advance by the precoating method to the forging equipment, and the lubricating effect may not be sufficiently obtained. This last problem was remarkable especially when the shape was large and the degree of processing was large.

An object of the present invention is to surely lubricate (reduce the coefficient of friction) even in a constant temperature forging having a large shape and a large workability.
A lubricant composition for constant temperature forging, which can exert a mold release effect, can be lubricated without using a precoat method, and enables continuous forging, and a constant temperature forging method using the same. That is.

[0010]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventors have found that a mixture of nickel powder and a certain borate can be mixed with water and sprayed. Knowing that it is effective, the present invention has been completed.

In the present invention, the nickel powder and at least one kind of borate selected from ammonium salts and amine salts of boric acid may be prepared by mixing nickel powder: borate in a weight ratio of 10:90 to 90:10 and further surfactants and / or thickeners in total 5% by weight of the total composition
It is a lubricant composition for constant temperature forging, which may be contained in the following amount.

According to the present invention, the lubricant composition 20
~ 80 parts by weight mixed with 80-20 parts by weight of water, 500
There is also provided a processing method by constant temperature forging, which comprises performing spraying on at least one of a workpiece and a mold heated to about 1000 ° C. and then performing constant temperature forging.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The essential components of the lubricant composition for constant temperature forging according to the present invention are nickel powder and one or more borates selected from ammonium salts and amine salts of boric acid. is there.

Nickel powder does not melt even at a constant forging temperature, and retains its powder shape to function as a solid lubricant. Conventionally, there has been no attempt to use nickel powder as a lubricant, but the present inventors have found that nickel powder is stable in isothermal forging and can function sufficiently as a solid lubricant.

On the other hand, when the borate is heated to a temperature of 500 to 1000 ° C., it decomposes to produce molten boron oxide (B ₂ O ₃ ). The molten (fluid) boron oxide wraps the solid nickel powder and acts to smoothly supply the powder to the lubricating surface (the interface between the high-temperature mold and the material to be processed). The material itself exerts a fluid lubrication effect. By converting boric acid into an ammonium salt or an amine salt, boric acid can be solubilized in water, thereby acting to uniformly attach boric acid (ions) to a lubricating surface. The attached borate ions are immediately decomposed when they come into contact with the high-temperature mold or the work material, and become molten boron oxide which functions as the above-mentioned fluid lubricant.

That is, in the lubricant composition of the present invention, nickel powder functions as a solid lubricant, and borate functions as a supply source of a fluid lubricant, and the lubricating effects of these two types of lubricants are high in combination. A lubrication effect can be exhibited.

The nickel powder preferably has an average particle size of 50 μm or less and a purity of 98% or more. If the average particle size of the nickel powder exceeds 50 μm, the dispersibility becomes poor, and it becomes difficult to uniformly supply the nickel powder when used as a slurry by mixing with water, and the storage stability in a slurry state also increases. descend. If the purity of the nickel powder is lower than 98%, lubricity is impaired by impurities mainly composed of inorganic substances existing as impurities.

As the borate, an ammonium salt or an amine salt is used. Borates that can solubilize boric acid in water include alkali metal borates (eg, sodium borate, potassium borate, etc.). Alkali metal borates are alkali metal oxides (E.g., Na
₂ O, K ₂ O) reacts with the mold at a constant temperature forging temperature and damages the mold. Other metal borate salts are generally water-insoluble and cannot solubilize boric acid in water.

As the ammonium borate, those precipitated by mixing an aqueous boric acid solution and aqueous ammonia can be used, and salts of (NH ₄ ) ₂ O and B ₂ O ₃ in various molar ratios can be used. It has been known. You can use any of these,
A mixture of two or more ammonium borates having different molar ratios may be used. Further, ammonium borate generally has water of crystallization, but may contain water of crystallization or may be anhydrous.

The borate amine salt is preferably a salt with an alkanolamine such as monoethanolamine, diethanolamine, triethanolamine, ethyl monoethanolamine, dimethylethanolamine, diethylethanolamine, ethyldiethanolamine and monoisopropanolamine. However, salts of boric acid with alkylamines such as monomethylamine, diethylamine, triethylamine, monomethyldiethylamine can also be used.

The mixing ratio of nickel powder and borate in the lubricant composition for constant temperature forging of the present invention is such that the weight ratio of nickel powder: borate is 10:90 to 90:10. When the weight ratio is out of this range, the balance between the solid lubricant and the fluid lubricant is poor, and the lubricating effect of the present invention cannot be sufficiently exhibited.
A preferred compounding ratio is that the weight ratio of nickel powder: borate is
20:80 to 80:20, especially 30:70 to 70:30.

The lubricant composition for constant temperature forging of the present invention may contain, in addition to the essential components nickel powder and borate, small amounts of optional components as long as they do not adversely affect the action of these essential components. It is preferable that the total amount of the optional components is 5% by weight or less based on the entire lubricant composition. Examples of suitable optional ingredients include surfactants and thickeners.

The surfactant has an effect of enhancing the dispersion stability of nickel powder in water. As the surfactant, any of a nonionic type, an anionic type and a cationic type can be used. Examples of suitable surfactants include, but are not limited to, polyoxyethylene nonyl phenyl ether, alkanolamides of fatty acids, sodium or ammonium salts of sulfonic naphthalene condensates, and the like. The amount of the surfactant added is usually based on the total weight of the composition.
Up to 2.5% by weight is sufficient.

When the thickener is added, the viscosity of the mixture when the lubricant composition of the present invention is mixed with water increases, and the dispersion stability of the nickel powder in the mixture increases. Examples of suitable thickeners include ammonium or alkali metal salts of carboxymethyl cellulose (eg, sodium salt) and the like. The amount of the thickener used is usually sufficient within 2.5% by weight of the total weight of the composition.

The constant temperature forging using the lubricant composition of the present invention can be carried out as described below. First, the lubricant composition of the present invention is mixed with water to dissolve the borate in water, and the nickel powder is dispersed in water. This mixing with water may be carried out immediately before use, or a mixed solution previously mixed with water may be stored. When storing the mixed solution, it is particularly preferable to add the above surfactant.

The mixing ratio of the lubricant composition and water in this mixture is in the range of 20:80 to 80:20 by weight. This weight ratio is preferably from 25:77 to 75:25, more preferably from 30:70 to 70:30. If the amount of water is too small, the viscosity of the mixed solution is high, which hinders spraying and may cause uneven adhesion of the lubricant composition. On the other hand, if there is too much water, the viscosity of the mixed solution is too low, and it becomes difficult for the mixture to adhere to a high-temperature mold or a material to be processed due to a popping (repelling) phenomenon, and the adhesion efficiency becomes extremely poor.

The mixed solution with water is sprayed onto at least one of the material to be processed and the mold heated to 500 to 1000 ° C., preferably 500 to 950 ° C., and then subjected to isothermal forging. It is preferable to spray the mixture on both the mold and the material to be processed, but depending on the degree of processing, the material of the mold, and the viscosity of the mixture, it is sufficient to spray only one of the mold and the material to be processed. In some cases, a lubricating effect and releasability can be obtained.

A mold having excellent heat resistance capable of maintaining mechanical strength under isothermal forging conditions and not forming an alloy or reacting with a material to be processed under these conditions is used. For constant temperature forging of β titanium alloy, use common superalloys (eg, IN 100)
Molds are used.

The heating temperature of the material to be processed and the mold is 500 to
The reason why the temperature is set to 1000 ° C. is that the temperature at which the lubricating performance of nickel powder is effective is within this temperature range. The heating temperature may be set within the above temperature range according to the forging temperature of the material to be processed. For example, since the isothermal forging temperature of a β-type titanium alloy is 700 to 950 ° C., the heating temperature is within this range.

Therefore, when the isothermal forging of the β titanium alloy is performed, the die and / or the material to be processed are heated to the forging temperature, and then a mixture of the lubricant composition of the present invention and water is mixed. Can be sprayed. When the temperature is reduced by the spraying, the temperature is reheated to a predetermined temperature. As another method, the die and / or the material to be processed is heated to a temperature higher than 500 ° C. and lower than the forging temperature, the above-mentioned mixed solution is sprayed, and the heating is continued to raise the temperature to the predetermined forging temperature. It can also be done.

The amount of the mixed solution sprayed varies depending on the proportion of water in the mixed solution and the viscosity of the solution, but is preferably an amount such that the amount of the attached nickel powder is 30 to 150 g / m ² . By spraying the mixture onto a hot mold and / or workpiece, water in the mixture evaporates, and the ammonia and amine components of the borate evaporate or decompose. A liquid (fluid) lubricant film in which the powder is dispersed is formed on the spray surface. After the spraying, if necessary, the workpiece is heated to a predetermined processing temperature, and the material to be processed is set in a mold and pressurized by a hydraulic press to perform constant temperature forging. The processing conditions may be set in the same manner as in the conventional constant temperature forging.

After the completion of the isothermal forging, the compact is removed from the mold by heating as in the prior art. If the temperature is higher than 500 ° C., the lubricant composition of the present invention is still in a fluid state.
The molded body can be easily removed from the mold. The lubricant component adhering to the molded body can be easily removed by shot blasting or the like.

The mold can be used for the next constant temperature forging operation immediately after the mold release. If necessary, heat the mold, raise the temperature to a temperature or a constant temperature forging temperature suitable for applying the lubricant composition of the present invention, spray the mixture, and perform the constant temperature forging in the same manner as described above. Do. Since the lubrication treatment is performed not by the precoating method but by spraying the heated mold before forging, the mold can be used continuously. If the previous lubricating film remains in the mold, the lubrication processing of the mold can be omitted or the spray amount can be reduced.

[0034]

【Example】

(Examples 1 to 8) Flaky nickel powder (average particle size 25 μm) or spherical nickel powder (average particle size 25 μm) was mixed with boric acid monoethanolamine salt and / or ammonium salt in the ratios shown in Table 1 below. Mix to form a solid mixture AF
Was prepared.

[0035]

[Table 1]

The above solid mixture was mixed with the anionic surfactant (sodium salt of a naphthalene sulfonate condensate), a thickener (sodium salt of carboxymethyl cellulose) and water in the proportions shown in Table 2 to prepare Examples 1 to 8. Was prepared.

Each of these mixed liquids was used in a thermostatic forging test of a molded body shown in FIG. 1 (a mold was made of IN 100, and a material to be processed was a β titanium alloy <Ti-10Al-2Fe-3V>). All of the mixed liquids had good adhesion at the time of spraying, and there were no problems in any of lubricity, releasability, and mold wear during forging. Also,
In each case, the mold could be used continuously (that is, after the mold was released hot, the same mixture was immediately sprayed without cooling and the next forging process was performed).

The temperature forging test was performed at a temperature of 750 ° C.
The test was performed under the conditions of a pressure of 3500 Ton by a hydraulic press and a pressurization time of 60 minutes. The mixture was sprayed when both the mold and the material to be processed were heated to 750 ° C., and the spray amount was 50 g / m ² as the amount of nickel powder deposited.

[0039]

[Table 2]

(Comparative Examples 1 to 5) For comparison, mixed liquids of Comparative Examples 1 to 5 having the compounding ratios shown in Table 3 were prepared, and these were used for isothermal forging test in the same manner as in Examples 1 to 8. Was done.
However, the mixed solution of Comparative Example 1 formed a lubricating film by a precoat method. The flaky nickel powder and thickener used were the same as those used in Examples 1-8.

The liquid mixture of Comparative Example 1 corresponds to the lubricant composition disclosed in Japanese Patent Application Laid-Open No. 54-1111056, which is a prior art. The composition of the glass powder, in weight percent, is Si
O ₂ : 43.4%, B ₂ O ₃ : 27.6%, Na ₂ O: 19.8%, CaO: 6.0
%, MgO: 1.3%, Al ₂ O ₃ : 1.1%, K ₂ O: 0.7%, Fe ₂ O ₃ :
0.1%. This glass exhibits a lubricating function by fluid lubrication by melting at the forging temperature and solid lubrication by SiC as an abrasive. However, this mixed solution was applied to both the mold and the work material, heated and dried to form a lubricating film, and then subjected to isothermal forging under the same conditions as above. The object and the mold reacted, resulting in mold wear. In addition, there was a problem in the releasability. Furthermore, since this mixture is applied by the precoat method, it cannot be used for continuous forging.

In Comparative Examples 2 and 3, similarly to the borate of the present invention, boric acid, which becomes a molten liquid of boron oxide (ie, a fluid lubricant) at the forging temperature, functions as a solid lubricant. This is an example of combining with boron nitride or fluorinated gold mica.

However, in Comparative Example 2, when the mold temperature was high, it was difficult to adhere to the mold even when sprayed. Further, during continuous operation, the spray nozzle may be clogged, and it is difficult to use the nozzle for continuous operation. Comparative Example 3
In the mixed solution of the above, there was a problem in the releasability because the melt of boron oxide generated from boric acid melts the fluorinated gold mica.

Comparative Examples 4 and 5 are examples in which nickel powder was used as a solid lubricant in the same manner as in the present invention, and this was combined with glass or borax which became molten at the forging temperature.

In Comparative Example 4, since the borax component Na ₂ O reacted with the mold, the mold was worn as in Comparative Example 1, and at the same time, there was a problem with the releasability. Also in Comparative Example 5,
Because glass containing alkali metal oxide was used,
Similarly, the mold was worn, and there was a problem in the releasability.

Comparative Example 6 is an example in which nickel powder is combined with boric acid. When boric acid is used in place of the ammonium or amine salt of boric acid, the solubility of boric acid in water is low, and Since the recrystallized grains precipitated by the change are coarse, workability during spraying is inferior.

Comparative Example 7 is an example of combining amine borate with abrasive particles (SiC) instead of nickel powder as a solid lubricant. However, SiC has no lubricity and has a problem in formability. Was.

[0048]

[Table 3]

[0049]

EFFECTS OF THE INVENTION The lubricant composition for constant temperature forging and the processing method according to the present invention have a sufficient lubricating effect (reduction in friction coefficient) for the die and the material to be processed for constant temperature forging without using the precoating method. Releasability can be imparted. As a result, lubrication is possible even for a constant-temperature forging having a large shape and a large workability. In addition, since a lubricating film can be formed by spraying the mold and the workpiece at a high temperature, the mold does not need to be cooled for each mold release as in the precoat method. Since the mold can be lubricated, continuous forging becomes possible. This gives β
The efficiency of constant temperature forging of titanium alloy etc. is greatly improved.

The lubricant composition and processing method of the present invention
In particular, it is suitable for isothermal forging of β-titanium alloy, but it is naturally applicable to isothermal forging of other metal materials whose working temperature is in the range of 500 to 1000 ° C.

[Brief description of the drawings]

FIG. 1 shows the shape of a compact in a constant temperature forging test performed in Examples and Comparative Examples, and FIG. 1 (a) is a perspective view, and FIG.
FIG. 2B is a cross-sectional view taken along line AA of FIG.

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C10M 103: 04) (C10M 111/02 103: 04 103: 00 105: 62) C10N 10:16 30:02 30:04 40:24 40: 36 50:02

Claims (3)

[Claims] A nickel powder and at least one type of borate selected from ammonium salts and amine salts of boric acid, wherein the weight ratio of nickel powder: borate is from 10:90 to 90:10.
A constant temperature forging lubricant composition containing the following proportions. 2. The lubricant composition according to claim 1, further comprising a surfactant and / or a thickener in an amount of not more than 5% by weight of the total composition. 3. The lubricant composition according to claim 1, wherein
A mixed solution obtained by mixing 20 to 80 parts by weight of water with 80 to 20 parts by weight of
A processing method by constant temperature forging, which comprises performing spraying on at least one of a material to be processed and a mold heated to 100 to 1000 ° C. and then performing constant temperature forging.