JP6912586B2 - Manufacturing method of titanium or titanium alloy green compact - Google Patents

Description

The present invention relates to a method for producing a titanium or titanium alloy green compact.

Titanium and titanium alloys have excellent mechanical properties, but are difficult to process, and complex-shaped products have traditionally been manufactured by cutting. However, in the case of manufacturing by cutting, there is a problem that the yield is low and the product unit price becomes very high.

As one of the methods for solving the above problems, a method for producing titanium and a titanium alloy green compact using a raw powder mixing method is known. In the raw powder mixing method, pure titanium powder and powder for adding alloying elements are mixed at a predetermined ratio, filled in a mold, compacted at room temperature, and then sintered or hydrostatically pressed (cold isometric). Pressure press: CIP) is a processing method that performs processing and the like.

For example, in Japanese Patent Application Laid-Open No. 7-90313, a powder molding mold is produced by a blow molding method using a thermoplastic resin, the powder molding mold is filled with titanium powder, and the mold is molded by a hydrostatic molding press. This describes a method for producing a molded article of titanium powder.

Japanese Unexamined Patent Publication No. 7-90313

However, in the method of forming a molded product by blow molding a thermoplastic resin as exemplified in Patent Document 1, a high-density molded product without cracking can be obtained, but the thickness accuracy is difficult to obtain. Therefore, the titanium or titanium alloy green compact produced by using the molded product produced by blow molding tends to have a deviation in external dimensions. In order to improve the accuracy of the external dimensions, there is a method of using a metal mold or the like, but it is expensive and it becomes difficult to manufacture a complicated shape.

In view of the above problems, the present invention provides a method for producing titanium or titanium alloy green compact, which has high accuracy in external dimensions and can more economically manufacture titanium or titanium alloy green compact having a complicated shape. do.

As a result of diligent studies, the present inventor has found that it is useful to use a CIP molding mold having a predetermined thickness range using a thermoplastic resin having a predetermined characteristic.

In one aspect, the present invention completed based on the above findings is a titanium or titanium alloy powder obtained by using a cold isotropic press to obtain a titanium or titanium alloy powder having a relative density of 80%, preferably 84% or more. A method for manufacturing a body, which is made of a thermoplastic resin having a thickness of 1.0 to 1.8 mm, a compressive modulus of 5 MPa to 100 MPa, and a shore D hardness of 30 to 65, and is used for a powder supply port and powder filling. A method for producing a titanium or titanium alloy green compact using a CIP molding mold having a cavity of is provided.

In one embodiment, the method for producing a titanium or titanium alloy green compact according to the present invention measures the thickness of any 10 points in the longitudinal direction of the CIP molding mold (maximum value-minimum value) / (maximum value). The mold thickness error range index α represented by (+ minimum value) is 0 to 0.05.

In another embodiment of the method for producing a titanium or titanium alloy green compact according to the present invention, the CIP molding mold is continuous with the large diameter portion and the large diameter portion, and the cross-sectional area of the horizontal cross section is larger than that of the large diameter portion. The ratio D (minimum diameter of small diameter part / maximum diameter of large diameter part) of the minimum diameter of the small diameter part to the maximum diameter of the large diameter part in the horizontal cross section is 0.5 or more and less than 0.8. Is.

In still another embodiment of the method for producing a titanium or titanium alloy green compact according to the present invention, in the CIP molding mold, the outer surface of the small diameter portion is inclined with respect to the outer surface of the large diameter portion, and the large diameter portion is formed. The angle θ formed by the straight line extending in the extending direction of the outer surface of the large diameter portion from the end of the outer surface of the small diameter portion and the outer surface of the small diameter portion is 10 degrees or more and less than 60 degrees.

In still another embodiment, the method for producing a titanium or titanium alloy green compact according to the present invention includes producing a mold for CIP molding using a 3D printer device.

In yet another embodiment, the method for producing a titanium or titanium alloy green compact according to the present invention includes producing a mold for CIP molding using a 3D printer device using a material extrusion method.

In still another embodiment, the method for producing a titanium or titanium alloy green compact according to the present invention includes producing a mold for CIP molding using a 3D printer device using a material injection method.

In still another embodiment of the method for producing a titanium or titanium alloy green compact according to the present invention, 80 to 100% by mass of pure titanium powder having an average particle size of 30 μm or more and less than 100 μm is filled in the cavity of a CIP molding mold. Including doing.

In still another embodiment, the method for producing a titanium or titanium alloy green compact according to the present invention comprises a pure titanium powder having an average particle size of 30 μm or more and less than 100 μm, and an alloy element powder or a mother alloy having an average particle size of 5 μm or more and less than 50 μm. It includes filling 1 to 20% by mass of the powder into the cavity of the CIP molding mold.

According to the present invention, it is possible to provide a method for producing titanium or titanium alloy green compact, which has high accuracy of external dimensions and can more economically manufacture titanium or titanium alloy green compact having a complicated shape.

It is sectional drawing which shows an example of the CIP molding mold which concerns on embodiment of this invention, and the measurement position (arbitrary 10 points) of the thickness of the CIP molding mold which is an example. It is explanatory drawing explaining the inclination angle θ of the large-diameter part and the small-diameter part of the mold for CIP molding which concerns on embodiment of this invention, and FIG. (B) is an example in which the small diameter portion has a curved slope.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention describes the structure, arrangement, etc. of the components as follows. It is not specific.

The method for producing a titanium or titanium alloy green compact according to an embodiment of the present invention is a titanium or titanium alloy having a relative density of 80% or more and further a relative density of 84% or more using a cold isotropic press (CIP). A method for producing a titanium or titanium alloy green compact that can obtain a green compact, for example, a CIP molding mold 1 having a powder supply port 2 and a powder filling cavity 3 as illustrated in FIG. Can be used.

In order to produce titanium or titanium alloy green compact having a high accuracy of external dimensions and having a complicated shape, the material of the CIP molding mold 1, the compressive modulus, and the shore D are related to the manufacturing process of the CIP treatment. It is necessary to adjust the hardness to an appropriate range and to increase the thickness and thickness accuracy of the CIP molding mold 1.

Specifically, the CIP molding mold 1 according to the present embodiment needs to have a thickness of 1.0 to 1.8 mm. If the thickness is less than 1.0 mm, the weight of the filling powder may deform the CIP molding mold 1 and reduce the dimensional accuracy. On the other hand, if the thickness is larger than 1.8 mm, there is no problem in the obtained green compact, but the cost of the molding material increases, which impairs economic efficiency.

Regarding the dimensional accuracy of the thickness, the mold thickness error range index α expressed by (maximum value-minimum value) / (maximum value + minimum value) when the thickness of any 10 points in the longitudinal direction of the mold is measured. Is preferably 0 to 0.05. When evaluating the dimensional accuracy of the thickness, if the thickness measurement points are locally biased, it may not be possible to appropriately evaluate the variation in the thickness of the CIP molding mold 1 as a whole. Therefore, in the present embodiment, as a measurement point of "arbitrary 10 points of thickness", it means a place where the longest surface of the CIP molding mold 1 is divided into 10 equal parts. For example, as shown in FIG. 1, the CIP molding mold 1 is allowed to stand on the horizontal plane so that the longitudinal direction along the maximum length of the CIP molding mold 1 faces the direction perpendicular to the horizontal plane, and the direction perpendicular to the horizontal plane. The thickness at each position (1 to 10) obtained by dividing the CIP molding mold 1 into 10 equal parts can be measured.

That is, as shown in FIG. 1, the “mold thickness error range index α” is an arbitrary height of the CIP molding mold 1 when the CIP molding mold 1 is divided into 10 equal parts along the longitudinal direction of the CIP molding mold 1. It refers to the error range index evaluated by measuring the thickness of the measurement point at the position and using the maximum and minimum values. The thickness can be measured, for example, by using a digital caliper or the like for each measurement point.

When the mold thickness error range index α becomes larger than 0.05, the accuracy of the external dimensions of the titanium or titanium alloy green compact produced by using the CIP molding mold 1 deteriorates, and the springback force is controlled. Becomes difficult and causes breakage. The mold thickness error range index α is preferably 0.01 or less, more preferably 0.008 or less, and further preferably 0.001 or less.

When the target thickness of the CIP molding mold 1, that is, the thickness data of the CIP molding mold 1 at the time of manufacturing is known, the dimensional accuracy of the CIP molding mold 1 is evaluated by the mold thickness error range index β. You can also. The mold thickness error range index β is a measurement point at an arbitrary position at each height when the mold thickness error range index β is divided into 10 equal parts along the longitudinal direction of the CIP molding mold 1 in the same manner as the measurement of the mold thickness error range index α. Refers to "(maximum value-minimum value) / target thickness" when the thickness of each is measured. As the target thickness, for example, the thickness of the three-dimensional CAD source data at the time of molding the CIP molding mold 1 can be used.

When the mold thickness error range index β becomes larger than 0.5, the accuracy of the external dimensions of the titanium or titanium alloy green compact produced by using the CIP molding mold 1 deteriorates, and the springback force is controlled. Becomes difficult and causes breakage. An error with a mold thickness error range index β of 0.5 or less does not affect the physical properties of the CIP molding mold 1. The mold thickness error range index β is preferably 0.2 or less, more preferably 0.1 or less, and further preferably 0.05 or less.

Alternatively, the absolute value of any 10 points (thickness / target thickness × 100-100) at each height when the CIP molding mold 1 is divided into 10 equal parts along the longitudinal direction of the CIP molding mold 1. The average value of is also evaluated as the mold thickness error range index γ. The mold thickness error range index γ is preferably less than 1.5, more preferably 1.0 or less, still more preferably 0.5 or less.

As the material used for the CIP molding mold 1, a thermoplastic resin is preferable, and among them, a material obtained by mixing an elastomer with a base acrylic material can be preferably used. By stepwise mixing the elastomer, which is a rubber component, with the base acrylic material, the compressive elastic modulus and hardness of the present embodiment can be adjusted. As the elastomer, styrene-based, olefin / alken-based, vinyl chloride-based, urethane-based, amide-based thermoplastic elastomers and the like can be mixed with the thermoplastic resin. For example, a material whose hardness is adjusted by mixing an elastomer such as urethane acrylate with an acrylic resin can be preferably used as a material for the CIP molding mold 1. The elastomer can be mixed in an amount of 15 to 65 mass% with respect to the thermoplastic resin.

The compressive elastic modulus of the thermoplastic resin material is preferably 5 MPa to 100 MPa. If the compressive elastic modulus is less than 5 MPa, the rigidity of the CIP molding mold 1 is insufficient, the CIP molding mold 1 is deformed by the weight of the filling powder, and the dimensional accuracy of the CIP molded product is significantly lowered. When the compressive elastic modulus is made larger than 100 MPa, the rigidity of the CIP molding mold 1 becomes high, and when the CIP molding mold 1 is springed back during CIP unloading, the internal green compact is loaded with a load greater than the green compact strength. , May lead to breakage of green compact.

The compressive elastic modulus of the thermoplastic resin used in the CIP molding mold 1 is more preferably 8 MPa to 70 MPa, further preferably 30 MPa to 60 MPa, still more preferably 40 MPa to 60 MPa. The compressive modulus can be measured by a test method conforming to JIS K7181 (2011).

The Shore D hardness of the thermoplastic resin used for the CIP molding mold 1 is preferably 30 to 65, more preferably 32 to 60. When the shore D hardness is less than 30, the rigidity of the CIP molding mold 1 is insufficient, and the shape cannot be maintained and the mold 1 is crushed. When the shore D hardness is made larger than 65, the rigidity of the CIP forming mold 1 becomes high, and when the CIP forming mold 1 is springed back during CIP unloading, the internal green compact is loaded with a load greater than the green compact strength. This may lead to breakage of the green compact. The shore D hardness can be measured by a test method based on JIS K7215 (1986).

As shown in FIG. 1, the CIP molding mold 1 is continuous with the large diameter portion 11 and the large diameter portion 11, and has a smaller horizontal cross-sectional area than the large diameter portion 11 from the small diameter portion 12 and the small diameter portion 12. Also includes a large diameter portion 13 having a large horizontal cross-sectional area and continuous with the small diameter portion 12, and a top portion 14 continuous with the large diameter portion 13 and having a powder supply port 2 at the top.

The horizontal cross-sectional area of the small-diameter portion 12 gradually decreases from the bottom to the top, becomes the minimum cross-sectional area at the intermediate portion, and the horizontal cross-sectional area gradually increases from the intermediate portion toward the large-diameter portion 13. It can have a shape with a horizontal constriction.

The large diameter portions 11 and 13 may have a polygonal horizontal cross section, or may have a circular or elliptical horizontal cross section, and may be appropriately changed according to the intended use, and have a specific shape. Is not particularly limited. _{Further, the ratio D of the minimum diameter D 12} of the small diameter portion 12 to _{the maximum diameter D 11 of the large diameter portions 11 and} 13 in the horizontal cross section (small diameter portion minimum diameter D ₁₂ / large diameter portion maximum diameter D ₁₁ ) is 0.5 or more. It is less than 0.8. The shapes of the large diameter portions 11 and 13 and the small diameter portions 12 are preferably substantially similar to each other in horizontal cross sections, but may have different shapes.

As shown in the enlarged view of FIG. 2A, in the CIP molding mold 1, the outer surface 121 of the small diameter portion 12 is inclined with respect to the outer surface 111 of the large diameter portion 11. An angle θ formed by a straight line X extending in the extending direction of the outer surface 111 of the large diameter portion 11 from the end 112 of the outer surface 111 of the large diameter portion 11 and the outer surface 121 of the small diameter portion 12 (example of FIG. 2A). Then, the angle θ) formed by the outer surface 121 of the small diameter portion 12 when measured counterclockwise from the straight line X is 10 degrees or more and less than 60 degrees. When the outer surface 121 of the small diameter portion 12 has a curved surface, as shown in FIG. 2B, the _{position where the minimum diameter D 12} is obtained in the horizontal cross section of the small diameter portion 12 and the end portion 112 of the large diameter portion 11 The angle θ formed by the straight line Y and the straight line X (that is, the angle formed by the straight line Y when measured counterclockwise from the straight line X with respect to the straight line X) is 10 degrees or more and less than 60 degrees.

The CIP molding mold 1 having a complicated shape as shown in FIGS. 1 and 2 (a) and 2 (b) can be manufactured by using a 3D printer device. As a result, the thickness can be made uniform and the dimensional accuracy can be improved as compared with the case where the mold is formed by blow molding as in the conventional case. Further, since it is not necessary to manufacture a mold or the like when manufacturing the mold, the CIP molding mold 1 having a more economically complicated shape can be manufactured so as to have high dimensional accuracy.

A general-purpose device can be used as the 3D printer device, but it is preferable to use a 3D printer device using a material extrusion method or a 3D printer device using a material injection method.

Titanium according to the present embodiment is formed by filling the cavity 3 in the CIP molding mold 1 according to the present embodiment with pure titanium powder or pure titanium powder and alloy element powder or mother alloy powder and performing CIP treatment. Alternatively, a titanium alloy green compact can be obtained. In the present embodiment, "pure titanium" means industrial pure titanium satisfying the composition specified in JIS Class 2. The alloy element powder is a single element powder such as Al powder or V powder, and the mother alloy powder is a powder containing a plurality of elements.

As the filler, for example, by filling 80 to 100% by mass of pure titanium powder having an average particle size of 30 μm or more and less than 100 μm into the cavity of the CIP molding mold, a titanium or titanium alloy green compact having a relative density of 80% or more is filled. Is obtained. Alternatively, 1 to 20% by mass of pure titanium powder having an average particle size of 30 μm or more and less than 100 μm and alloy element powder or mother alloy powder having an average particle size of 5 μm or more and less than 50 μm are filled in the cavity 3 of the CIP molding mold 1. By carrying out the CIP treatment, a titanium or titanium alloy green compact having a relative density of 80% or more can be obtained. The powder filling and CIP treatment can be carried out under generally well-known conditions. The average particle size refers to the value of the particle size D50 (median diameter) of the particle size distribution (volume basis) obtained by the laser diffraction / scattering method. The main alloy systems used for titanium alloy powders are Ti-6Al-4V, Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-2Mo, Ti-6Al-2Sn-4Zr-6Mo, Ti. -10V-2Fe-3Al and the like can be mentioned.

According to the titanium or titanium alloy green compact according to the embodiment of the present invention, a mold for CIP molding in which the thickness and thickness accuracy are controlled by using a predetermined thermoplastic resin using a 3D printer. By obtaining 1 and performing a CIP treatment using this, titanium or a titanium alloy green compact having a high accuracy in external dimensions and a complicated shape can be produced more economically.

Examples and comparative examples of the present invention will be described below, but it goes without saying that the present invention is not limited to the following examples.

Based on the 3D data of the CIP molding mold whose thickness is adjusted between 0.5 and 1.75 mm, a mixture of an elastomer and an acrylic resin as a thermoplastic resin (hereinafter referred to as "acrylic + elastomer"). And an acrylic resin and a silicon resin, a mold for CIP molding was produced by a 3D printer. As the resin material composed of acrylic + elastomer, two types having different compressive elastic modulus and shore D hardness were used. A mold for CIP molding using acrylic + elastomer and acrylic as the thermoplastic resin was produced by a material injection method using a 3D printer device ProJet5500X manufactured by 3D Systems. A mold for CIP molding using a silicon resin material as a thermoplastic resin was produced by a material injection method using a 3D printer device AGILISTA-3200 manufactured by KEYENCE. The ratio D of the large diameter part to the small diameter part of the CIP molding mold is set to 0.6, and the angle θ between the large outer diameter and the small outer diameter is set to 27 degrees to obtain the CIP molding mold having the shape shown in FIG. Made.

The cavity in the prepared CIP molding mold was filled with pure titanium powder TC-150 (particle size width 45-150 μm, average particle size 90 μm) manufactured by Toho Tech, and CIP treatment was performed. For the CIP treatment, a cold hydrostatic pressure forming apparatus CL4-22-60 manufactured by Nikkiso Co., Ltd. was used.

The cavity in the prepared CIP molding mold is filled with pure titanium powder, tapped, sealed with vinyl tape, vacuum packed, and the vacuum packed pure titanium powder filled product is set in a cold hydrostatic molding device. And pressurized. When it reached about 300 MPa, it was held for 1 minute and then decompressed, and the titanium powder-filled product was taken out from the cold hydrostatic molding apparatus. The obtained molded product was heated at atmospheric pressure and 130 ° C. for 15 minutes, and the softened CIP molding mold was removed using a cutter, nippers, or the like to obtain a green compact.

The mold thickness error range indices α, β, γ, compressive elastic modulus, shore D hardness, and powder density (relative density) were measured for the CIP molding molds produced using each material and each device. As the target thickness, the thickness at the time of creating 3D data was used. The CIP molding mold 1 was divided into 10 equal parts in the longitudinal direction (12 mm intervals in this example), and the thickness of 10 points was measured with a tickness gauge. The compressive elastic modulus was calculated from the measurement results carried out in accordance with JIS K7181 (2011). Shore D hardness was measured according to JIS K7215 (1986). The green compact density was calculated from the density / theoretical density 4.51 / cm ^{3 × 100 obtained by the Archimedes method.} Furthermore, the presence or absence of breakage of the obtained green compact was observed. The results are shown in Table 1.

In Comparative Examples 1 and 2 in which the CIP molding mold having a thickness of 0.5 mm was produced, the CIP molding mold could not be produced. Even in Comparative Example 5 having a thickness of 1.0 mm using a silicon resin, a mold for CIP molding could not be produced. In Comparative Examples 3 and 4 using an acrylic resin whose compressive elastic modulus and shore D hardness were outside the range of the present invention, a mold for CIP molding could be produced, but the obtained green compact was broken. occured. In Comparative Example 6, although the mold could be produced, the shape could not be maintained during the CIP treatment due to insufficient strength, and crushing occurred. In Examples 1 to 4, it was possible to prepare a green compact having a relative density of 84% and no breakage.

1 ... CIP molding mold 2 ... Powder supply port 3 ... Cavity 11 ... Large diameter part 12 ... Small diameter part 13 ... Large diameter part 14 ... Top 111, 121 ... Outer surface 112 ... End

Claims (7)

A method for producing a titanium or titanium alloy green compact obtained by using a cold isotropic press to obtain a titanium or titanium alloy green compact having a relative density of 80% or more.
It is made of a thermoplastic resin with a thickness of 1.0 to 1.8 mm, a compressive elastic modulus of 5 MPa to 100 MPa, and a shore D hardness of 30 to 65. The mold thickness error range index α represented by (maximum value-minimum value) / (maximum value + minimum value) when measured is 0 to 0.05, and the powder supply port and the cavity for powder filling are separated. A mold for CIP molding to be possessed is produced using a 3D printer device.
A method for producing a titanium or titanium alloy green compact, wherein a filler is filled in the cavity of the CIP molding mold, and after filling, cold isotropic pressing is performed without heat treatment. The CIP molding mold includes at least a large-diameter portion and a small-diameter portion that is continuous with the large-diameter portion and has a smaller cross-sectional area in the horizontal cross section than the large-diameter portion, and the maximum of the large-diameter portion in the horizontal cross section. The titanium or titanium alloy dust powder according to claim 1 , wherein the ratio D of the minimum diameter of the small diameter portion to the diameter (minimum diameter of the small diameter portion / maximum diameter of the large diameter portion) is 0.5 or more and less than 0.8. How to make a body. In the CIP molding mold, the outer surface of the small diameter portion is inclined with respect to the outer surface of the large diameter portion, and the outer surface of the large diameter portion extends from the end of the outer surface of the large diameter portion. The method for producing a titanium or titanium alloy green compact according to claim 1 or 2 , wherein the angle θ formed by the straight line extending in the direction and the outer surface of the small diameter portion is 10 degrees or more and less than 60 degrees. The method for producing a titanium or titanium alloy green compact according to any one of claims 1 to 3 , wherein the mold for CIP molding is produced by using a 3D printer device using a material extrusion method. The method for producing a titanium or titanium alloy green compact according to any one of claims 1 to 3 , wherein the mold for CIP molding is produced by using a 3D printer device using a material injection method. The titanium or titanium alloy according to any one of claims 1 to 5 , which comprises filling 80 to 100% by mass of pure titanium powder having an average particle size of 30 μm or more and less than 100 μm into the cavity of the CIP molding mold. Method for producing green compact. A pure titanium powder having an average particle size of 30 μm or more and less than 100 μm and an alloy element powder or a mother alloy powder having an average particle size of 5 μm or more and less than 50 μm are filled in the cavity of the CIP molding mold in an amount of 1 to 20% by mass. The method for producing a titanium or titanium alloy green compact according to any one of claims 1 to 5, which comprises.

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