JP2011068961A - PESTLE AND MORTAR FOR MOLDING TABLET USING Ni-Cr-Al SYSTEM ALLOY - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pestle and a mortar for molding a tablet using an Ni-Cr-Al system alloy having reduced variation in the concentration of Cr. <P>SOLUTION: The pestle and mortar for molding a tablet use an Ni-Cr-Al system alloy having a composition composed of, by mass, 30 to 45% Cr and 2 to 6% Al, and the balance Ni with inevitable impurities, and in which the variation in the concentration of Cr in the unit area of 500×500 μm is ≤3 mass%. The segregation of Cr in the Ni-Cr-Al system alloy caused by cooling unevenness is reduced by the control of the size of an ingot and the temperature of a mold. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a tableting punch and mortar suitable for tableting a raw material containing a corrosive substance such as acidic powder.

Conventionally, when compressing raw materials such as powders and granules to form tablets such as pharmaceuticals, quasi-drugs, cosmetics, agricultural chemicals, feeds, foods, etc., a mortar having a through-hole according to the tablet shape, A molding die is used in which a lower punch and an upper punch inserted into a through hole (mortar hole) of the die are combined. In a tablet molding machine using such a mold, a desired tablet is molded by first filling a raw material such as a powder into a die into which a lower punch is inserted and compressing the raw material with an upper punch. The

Examples of molds used in tablet molding machines include iron-based alloys such as alloy tool steels (eg, SKS2 and SKD11), or Mo and W, as described in, for example, JP-A-7-8540. Conventionally, cemented carbides mainly composed of these compounds have been used.

However, these conventional mold alloys do not necessarily have satisfactory characteristics in terms of corrosion resistance and strength, and depending on the properties of the raw materials, there is a problem that the mold life is significantly reduced. Yes.

For example, with the diversification of applications in recent years, it has become necessary to press-mold highly corrosive powders such as acidic powders and alkaline powders. For molding such highly corrosive powder,
When using a conventional mold made of alloy tool steel or the like, the surfaces thereof are corroded early. Corrosion on the mold surface causes a reduction in the releasability of the raw material powder, and further causes strength deterioration.

In addition, in order to improve the corrosion resistance of a mold made of alloy tool steel or the like, it has been attempted to coat the surface with chrome plating, but a sufficient effect has not been obtained due to peeling of the plating layer. Although the chrome plating layer shows a certain effect on the improvement of surface hardness,
Since the film itself easily peels off, it is not possible to obtain an effect of improving wear resistance sufficiently and stably. From this, while maintaining the strength and hardness of the mold member,
It is desired to improve the corrosion resistance and wear resistance.

In order to solve such a problem of wear resistance, Japanese Patent Application Laid-Open No. 2001-62595 (Patent Document 1) describes a tablet molding pestle and a die having high hardness and high corrosion resistance. This alloy has both high hardness and high corrosion resistance, but also has mold release properties. Although it has good mold release properties for several hours immediately after tablet formation, further improvement in mold release properties is desired for mass production. It was. Further, since this alloy has a relatively low fatigue strength, it has been desired to increase the strength and to provide a mirror finish on the molding surface.

For example, Japanese Patent Application Laid-Open No. 63-18031 (Patent Document 2) discloses a hot press die having excellent corrosion resistance, Cr 20-50% by mass, Al 1.5-9% by mass, and the balance being substantially Ni. The mold is described. This press mold has a temperature of 500 to 800 ° C. and a press pressure of 500 to
It has characteristics such as high hardness with respect to hot pressing at 2000 kg / cm ² (50 to 200 MPa), buckling resistance, and corrosion resistance with Ni or Cr. However, although the mold parts made of this Ni-Cr-Al alloy are excellent in material hardness and corrosion resistance, they do not necessarily have sufficient wear resistance, and wear on the sliding parts of the parts depending on the use conditions. Progresses and the component life is shortened.

It is desired that resin molds such as resin lenses and engineering plastics have good mirror finish. Conventional steel is an alloy that is hardened by a relatively large carbide precipitated. For this reason, the occurrence of small holes due to the falling of the precipitated carbide particles during polishing, damage to the polished surface due to the falling particles,
Mirror finish processing was difficult. In addition, Ni plating or CrN coating is applied to improve the releasability of conventional steel materials, but it is not a satisfactory releasability. There was a problem to do.

In order to further improve the properties, International Publication No. 2006/035671 pamphlet (Patent Document 3) describes the X-ray diffraction intensity after aging treatment of Ni—Cr—Al alloy as a mold. It is disclosed to improve the properties. Thereby, an unaged structure | tissue can be reduced.

  However, it has been found that control of an unaged tissue as in the past is not sufficient.

In pursuit of this cause, Ni-Cr-Al alloy is prone to segregation of Cr, and where there is a large amount of segregation of Cr, fine unevenness is likely to occur on the mirror surface after polishing due to the difference in hardness from its periphery after aging heat treatment. There was a problem.

JP 2001-62595 A JP-A 63-18031 International Publication No. 2006/035671 Pamphlet

Conventional Ni—Cr—Al alloys cannot sufficiently improve Cr segregation. As a result, a partial hardness difference occurred, and fine irregularities were generated on the polished surface when the polishing process was performed. If the fine irregularities remain, the surface cannot be flattened. For example, in applications such as molds, the molding surface must be flattened. With conventional materials, the polishing process takes longer than necessary to eliminate fine surface irregularities,
Even if polishing is performed over time, it may not be improved and may become defective. When a die is molded using a surface that is not a uniform flat surface, the surface of the molded product becomes uneven, and there is a problem that a beautiful molded product cannot be made.

The present invention is for solving such problems, and by reducing Cr segregation, eliminating a partial hardness difference, and after removing fine irregularities on the polished surface when polishing is performed, An object of the present invention is to provide a tablet-molding pestle and mortar using a Ni-Cr-Al-based alloy with improved releasability and mirror finish on the molding surface.

In the tablet-forming pestle and die of the present invention, the Ni—Cr—Al-based alloy contains 30 to 4 Cr.
5% by mass, 2 to 6% by mass of Al, the balance is made of Ni and inevitable impurities, and variation in Cr concentration with a unit area of 500 μm × 500 μm is 3% by mass or less. Moreover, it is preferable that the average hardness is Hv150 or more and Hv200 or less. In addition, when the unit area of 500 μm × 500 μm is divided into 25 small units of 100 μm × 100 μm, 3 out of 25 small units whose Cr concentration is shifted by 1.5% or more from the average of the unit areas.
It is preferable that the number is less than or equal to 0 (including 0).

Further, it is preferable that the tablet forming punch and die are made of the Ni—Cr—Al-based alloy, have an average hardness of Hv600 or more and Hv750 or less, and a hardness variation of the same plane is 2.0% or less. Moreover, it is preferable that the maximum value of the surface unevenness of a portion where a part or all of the surface is polished is 0.5 μm or less. The area of the polished part is 10
It is preferably mm ² or more. Further, the surface roughness Ra is preferably 1 μm or less.

Further, in the tablet forming punch and die of the present invention, the Ni—Cr—Al alloy is composed of 3 Cr.
0 to 45 mass%, Al containing 2 to 6 mass%, the balance of Ni and raw materials that are inevitable impurities are mixed and melted to prepare a Ni-Cr-Al-based alloy molten metal, and the Ni-Cr- Al
A step of preparing an ingot having a shortest distance from the cooling surface of the mold of 120 mm or less using a molten alloy of the mold, and a Ni—Cr— having a hardness Hv of 150 to 200 by solution treatment of the ingot.
A step of preparing an Al-based alloy, a step of machining the Ni-Cr-Al-based alloy, and 5
It comprises a step of performing an aging heat treatment at 00 to 750 ° C. and a step of performing a surface polishing process.

The ingot size is preferably 80 mm or less at the longest distance from the cooling surface. Further, casting is preferably performed at a mold temperature of 50 ° C. or higher and 200 ° C. or lower. Also,
In the step of casting the ingot, the thickness of the mold is preferably 50 mm or more.

Moreover, it is preferable that the surface roughness Ra after polishing is 1 μm or less.

The present invention is for solving such a problem, and by reducing Cr segregation of the Ni—Cr—Al based alloy, a partial hardness difference is eliminated and the polishing surface is subjected to polishing. An object of the present invention is to provide a tableting punch and die using a Ni-Cr-Al alloy having a flat polished surface with reduced fine irregularities.

It is a figure which shows the principal part structure of the one structural example of the tablet molding machine using the tableting punch and mortar of this invention in a partial cross section. The figure which shows an example of an ingot. The figure which shows unit area 500 micrometers x 500 micrometers.

As the Ni—Cr—Al based alloy applied to the tablet forming punch and die of the present invention, Cr
30 to 45% by mass, Al 2 to 6% by mass, the balance is made of Ni and inevitable impurities, and the variation in the cross-sectional Cr concentration of unit area 500 μm × 500 μm is 3% by mass or less. is there.

Cr (chromium) is a material for ensuring corrosion resistance and workability, and is preferably 30 to 45 mass%, more preferably 35 to 41 mass%. If it is less than 30% by mass, the corrosion resistance is insufficient, and if it exceeds 45% by mass, segregation of Cr tends to occur and the workability is lowered. Al (aluminum) is a material for adjusting the hardness. The content is preferably 2 to 6% by mass, more preferably 3 to 5% by mass. The balance is Ni (nickel).

Inevitable impurities indicate elements other than Ni, Cr, and Al, but their contents are 1 in total.
The mass% or less is preferable. Further, as components other than Ni, Cr and Al, Zr (zirconium), Hf (hafnium), V (vanadium), Ta (tantalum), Mo (molybdenum),
At least one element selected from W (tungsten) and Nb (niobium) is 0.2
You may make it contain -2 mass%. These elements are effective for improving the hardness of the alloy material.

Further, Mg (magnesium) is effective as a deoxidizer, and the amount added is 0.001 to 0.001.
0.015 mass% is preferable. If it is less than 0.001% by mass, the effect of addition is insufficient.
. If it exceeds 015% by mass, not only the effect cannot be obtained but also the hardness may be lowered.

The tablet forming pestle and mortar of the present invention is characterized in that, in the Ni—Cr—Al alloy having the above alloy composition, the variation in Cr concentration of a unit area of 500 μm × 500 μm is 3% by mass or less. is there. Also, the smaller the variation in Cr concentration, the better, preferably 2
It is below mass%.

The variation in Cr concentration is performed by SEM-EDX method (X-ray spectroscopy using an energy dispersive X-ray spectrometer). An arbitrary measurement surface (a cut surface may be used for measurement) of a pestle and mortar or a Ni—Cr—Al alloy is selected, and a unit area of 500 μm × 500 μm is selected with SEM-E.
The average Cr amount is measured by the DX method, the measurement part is divided into 100 μm × 100 μm units (small units), and the Cr amount is analyzed for each small unit (100 μm × 100 μm). The variation in Cr concentration is the maximum value (% by mass of Cr) −minimum value (unit: 100 μm × 100 μm).
Cr mass%) = Cr concentration variation (mass%).

The Ni—Cr—Al-based alloy used for the tablet-forming pestle and die of the present invention has a Cr concentration variation of 3% by mass or less. If it exceeds 3% by mass, a Cr-rich region is partially formed and a hardness difference occurs. By reducing Cr segregation, a partial hardness difference is eliminated and polishing is facilitated. The smaller the variation in Cr concentration, the better. However, considering the complexity of production management, the variation in Cr concentration is preferably 0.5 to 1.4% by mass. In the same way, A
When l is analyzed, the variation in Al concentration is 0.5% by mass or less, and further 0.1 to 0.3% by mass
Is preferred.

Moreover, the Ni-Cr-Al type alloy used for the tablet molding punch and mortar indicates a solution obtained by subjecting an ingot after casting to plastic processing such as forging and rolling and subjecting it to a solution treatment. In addition, tablet forming pestle and mortar indicate a Ni-Cr-Al-based alloy processed and subjected to an aging heat treatment, and a polished product.

In addition, the Ni—Cr—Al alloy used for the tableting punch and die has a unit area of 500.
When μm × 500 μm is divided into 25 small units of 100 μm × 100 μm, it is preferable that the number of small units whose Cr concentration is shifted by 1.5% or more from the average unit area is 3 or less in 25. In addition to reducing the Cr concentration variation (maximum value-minimum value) to 3% by mass or less, it is effective in reducing Cr segregation to suppress concentration deviation as much as possible. The unit area 500 in FIG.
A diagram in which μm × 500 μm is divided into 25 small units of 100 μm × 100 μm is shown. First, using the SEM-EDX method, the Cr concentration is obtained in a visual field having a unit area of 500 μm × 500 μm, and this value is taken as an average value. Next, the Cr concentration is analyzed in a visual field of a small unit of 100 μm × 100 μm. This operation is performed for 25 small units, and the number of small units whose Cr concentration is shifted by 1.5% or more compared with the average value is counted. In the present invention, when such an analysis method is used, Cr
The number of small units whose density is shifted by 1.5% or more from the average unit area is 3 or less (including 0) of 25 units.

In addition, Ni—Cr—Al alloys used for tablet molding pestles and mortars have an average hardness of H
It is preferable that it is v150-200. In particular, it is preferable that the hardness of the Ni—Cr—Al alloy obtained by subjecting the ingot after casting to forging and rolling and solution heat treatment is in the range of Hv 150 to 200. Within this range, the average hardness after aging heat treatment is Hv600 to 750.
Easy to adjust to the range.

In order to make a tablet-forming punch and die, it is manufactured in an ingot shape by a melting method, and then subjected to mechanical processing such as forging, rolling, and punching to prepare the shape. Next, an aging heat treatment is applied to improve the hardness. The tablet forming pestle and die in the present invention reduce Cr segregation in the Ni—Cr—Al alloy, so the average hardness is Hv600 or more and Hv750 or less, and the hardness variation is 2.0% or less. It can be.

The measuring method of hardness is performed with a load of 1 kg based on JIS-Z-2244. Measure five points on the same measurement surface and determine the average value. The variation in hardness is obtained by [(maximum hardness−minimum hardness) / (average value of hardness)] × 100%. In addition, if there are places where the hardness is measured, select any five locations from the polishing portion (the location where the polishing process),
The hardness Hv shall be measured at each location.

Since the tablet forming punch and die in the present invention have reduced Cr concentration variation of the Ni—Cr—Al alloy, the hardness of the wear-resistant member is increased to Hv600 or more and Hv750 or less,
Furthermore, the hardness variation can be reduced to 2.0% or less. In addition, a polished surface without fine irregularities can be obtained when polishing is performed. For this reason, the polishing time can be shortened even if a mirror polishing process is performed with a surface roughness Ra of 1 μm or less, and further 0.5 μm or less. Therefore, the polishing efficiency is improved. Further, when such mirror processing is performed, the surface unevenness of the polished portion can be flattened to 0.5 μm or less. For this reason, the defect occurrence rate is also reduced and the product yield is improved.

Conventionally, the surface roughness Ra was simply managed, but if the segregation of Cr is not controlled, the same Ra1
Even when the thickness is μm, the surface unevenness of the polished surface was as large as 1.5 μm or more. When the cause of this surface unevenness was investigated, it was found that there was a cause of surface unevenness at the boundary of the Cr segregation part.

On such a polished surface, for example, when it is used for tablet molding pestles and mortars for making molded products, the surface irregularities of the molded products become large, and there is a problem that the molded products cannot be made clean or the releasability of the molded products is insufficient. there were. By reducing Cr segregation in Ni-Cr-Al alloys as in the present invention, the surface irregularity can be reduced to 0.5 μm or less, so that the surface is smooth when applied to tablet molding ridges and mortars that make molded products. It is possible to make tablet forming pestle and mortar with good releasability.

Moreover, the measuring method of surface unevenness | corrugation shall measure a grinding | polishing surface with a surface roughness meter, calculates | requires a cross-sectional curve, and calculates | requires the largest unevenness | corrugation difference. The unevenness difference is the difference between adjacent recesses and protrusions, and the largest unevenness difference is defined as the maximum surface unevenness.

Moreover, since the surface unevenness | corrugation after grinding | polishing processing can be made small, the area of the location polished is 10 mm < ² >.
A flat surface can be obtained even if the polishing portion is wide as described above. Therefore, the length of the short side is 4
Even if it is a wear-resistant member having a width of at least mm, there is no unevenness in polishing and a uniform mirror surface can be obtained.

The Ni—Cr—Al-based alloy used in the tablet-forming pestle and mortar of the present invention is a material exhibiting high hardness and high corrosion resistance. It is suitable when molding tablets for external products, cosmetics, agricultural chemicals, feeds, foods and the like.

The Ni—Cr—Al-based alloy used in the tablet molding pestle and mortar of the present invention can make the surface irregularities of the molding surface of the pestle and the mortar hole (through hole) of the mortar 0.5 μm or less, so the surface is smooth and separated. It is possible to make molds and mortars with good moldability. In addition, since it has good corrosion resistance, even when it is applied to pestle and mortar of raw material containing corrosive substances such as acidic powder, the corrosion progress of pestle and mortar accompanying contact with corrosive substances is prevented. It can be greatly reduced. This means that the mold releasability (for example, powder separation) accompanying the corrosion of the mold surface, and further the strength reduction is suppressed. Therefore, it is possible to achieve a long life of the pestle and the mortar.

The method for producing a Ni—Cr—Al based alloy used for the tableting punch and die of the present invention is C
a step of mixing 30 to 45% by mass of r and 2 to 6% by mass of Al, with the balance being Ni and raw materials that are inevitable impurities, and melting to prepare a Ni—Cr—Al alloy melt; −
A step of preparing an ingot having a maximum distance from the cooling surface of the mold of 120 mm or less using a molten Al alloy, and a Ni—Cr having a hardness Hv of 150 to 200 by solution treatment of the ingot.
-A step of preparing an Al alloy material, a step of machining the Ni-Cr-Al alloy material, a step of aging heat treatment at 500 to 750 ° C, and a step of surface polishing. It is characterized by.

First, Cr, Al, Ni as raw materials, Zr, Hf, V, Ta, Mo, W as required
, A predetermined amount of an element selected from Nb is weighed, mixed and dissolved. At this time, if a vacuum melting method is used, it is possible to reduce the mixing of impurities during melting.

An ingot is manufactured by pouring a raw material melt obtained by melting the raw material into a mold. At this time, the ingot size is adjusted so that the shortest distance of the ingot from the cooling surface of the mold is 120 mm or less. The cooling surface of the mold refers to a surface in contact with the raw material melt in the mold (that is, the inner surface of the mold becomes the cooling surface). For example, in the case of a cylindrical ingot having a diameter <length, the radius of the ingot is the shortest distance from the cooling surface to the ingot. In the case of manufacturing a rectangular column ingot or a flat plate ingot having a square short side length <length, the length to the center point in the cross section in the thickness direction is the shortest distance from the cooling surface to the ingot. In the case of a cylindrical ingot with a diameter> length, half of the length of the ingot in the thickness direction is the shortest distance from the cooling surface to the ingot. FIG. 2 shows an example of an ingot. The arrow indicates the diameter, and the shortest distance from the cooling surface to the ingot indicates the radius of the cylinder.

By reducing the size of the ingot to a radius of 120 mm or less, and further to a radius of 80 mm or less, cooling unevenness during cooling can be eliminated. The mold temperature is 50 ° C or higher and 200 ° C.
Casting is preferably performed as follows. By adjusting the ingot size and mold temperature, the ingot can be rapidly cooled to eliminate uneven cooling. By quenching,
Since the molten raw material mixed uniformly can be made into an ingot as it is, Cr segregation in the ingot can be eliminated.

In the manufacturing method of the Ni—Cr—Al alloy according to the present invention, it is important to control so as not to cause uneven cooling, and particularly to manage the cooling process so as not to be in a partially decooled state. In order to eliminate uneven cooling, it is effective to make the ingot small, but if it is too small, the mass productivity is lowered, so the length of the short side of the ingot is preferably 30 mm or more. The short side length of the ingot indicates the diameter of a circle of the cylindrical ingot, and in the case of a quadrangular columnar ingot, the short side of the square.

In addition, it is effective to use a thick mold having a mold thickness of 50 mm or more, and further 100 mm or more, in order to prevent uneven cooling. The mold is made of an iron alloy such as cast iron or carbon steel. By increasing the thickness of the mold, the heat capacity of the mold can be increased and cooling unevenness can be reduced.

Thus, the cooling process is managed to reduce the segregation of Cr, and then the ingot is prepared. Next, the obtained ingot is subjected to forging, rolling, and surface polishing as necessary to adjust the shape. The forging process and the rolling process may be performed hot. Thereafter, solution heat treatment is performed by heat treatment at 1000 to 1300 ° C. After the solution heat treatment, the hardness Hv of the alloy material is preferably 150 to 200. Even if Cr segregation is reduced, if the hardness of the ingot is as small as less than 100, the desired hardness cannot be obtained after the aging treatment described later. Moreover, when it exceeds 200, it will become hard too much and it will be difficult to cut. Further, the solution heat treatment is preferably a vacuum heat treatment in an argon atmosphere in order to prevent contamination such as oxidation.

Next, a process of machining the obtained Ni—Cr—Al alloy material is performed. The machining indicates a process for performing plastic working such as forging, rolling, cutting, cutting, and punching. Moreover, various processes may be combined as needed, and a washing process or a heat treatment process may be inserted in the middle. By this machining, the shape of the finally used tablet forming punch and mortar is processed to a shape close to that.

Next, the process of performing an aging heat processing at 500-750 degreeC is performed. The heat treatment time is 1-15.
Time is preferred. In addition, aging heat treatment is performed in an argon atmosphere to prevent contamination such as oxidation.
It is preferable to use vacuum heat treatment. It is also effective to perform pretreatment heating before aging heat treatment as described in Patent Document 3 in order to eliminate the unaged structure. As preferable pretreatment heating before the aging heat treatment, for example, (i) a temperature of 400 to 700 ° C., a temperature rising rate of 100 ° C./h or more, 500 ° C./h or less, preferably 100 ° C./h or more, 400 ° C./h In the following, mention may be made of heating by (b) or (b) holding for at least 0.5 hours in the temperature range of 400 to 500 ° C. Here, when the rate of temperature increase in the above (a) is slower than 100 ° C./h, the characteristics appear, but it takes too much time for processing, which is not preferable in production. On the other hand, if the rate of temperature rise is excessive such that it exceeds 500 ° C./h, volume shrinkage due to non-uniform temperature distribution and precipitation may become excessive, leading to crack generation. When the holding time in (b) is less than 0.5 hours, the effect of this pretreatment heating may not be sufficiently obtained. The upper limit of the holding time is preferably 5 hours. Even if the heat treatment is performed for more than 5 hours, it is difficult to obtain further effects.

Next, a step of performing surface polishing is performed. The surface polishing process has a surface roughness Ra of 1 μm or less,
Further, it is applied to a place where mirror processing of Ra 0.5 μm or less is necessary. For example, in the case of a tableting punch and mortar, the inner surface is polished. Examples of the polishing method include polishing using a diamond grindstone, such as polishing polishing. Moreover, you may perform cutting etc. as needed.

Next, an example of a tablet molding machine using a tablet molding die as a tablet molding die and mortar according to the present invention will be described. FIG. 1 is a partial cross-sectional view of the main structure of a tablet molding machine. In the tablet molding machine 10 shown in the figure, an upper punch 1, a lower punch 2 and a mortar 3 are shown.

The mortar 3 is mounted with a mortar 11 so that the mortar hole 3a is positioned in the vertical direction. The upper rod 1 and the lower rod 2 are held slidably in the vertical direction by the upper rod holding plate 12 and the lower rod holding plate 13, respectively.

The mortar 3 is mounted with a mortar 11 so that the mortar hole 3a is positioned in the vertical direction. The upper rod 1 and the lower rod 2 are held slidably in the vertical direction by the upper rod holding plate 12 and the lower rod holding plate 13, respectively.

The molding part 2a of the lower jaw 2 is inserted into the mortar hole 3a, and the head 2b of the lower jaw 2 is in contact with the lower jaw guide 14 in this state. A raw material 15 is filled in a container constituted by the molding part 2a of the lower punch 2 and the mortar 3a. As the raw material, various powders, granules, gels, high-viscosity liquids, mixtures thereof and the like are used.

A molding part 1a of the upper punch 1 is inserted into the mortar hole 3a filled with the raw material 15. Then, by pressing the head 1b of the upper punch 1 through the pressure guide 16, the filled raw material 15 is compressed from above and below to form a tablet. Note that the tablet molding machine 10 has a pressurizing unit (not shown), and thereby a necessary pressure is applied to the pressurizing guide 16.

In this tablet molding machine 10, mold assembly parts (at least the molding part) such as the upper punch 1, the lower punch 2, and the mortar 3 are formed of the Ni—Cr—Al alloy with reduced Cr segregation described above. Therefore, since the surface irregularities of the ridges 1 and 2 and the mortar 3 can be made 0.5 μm or less, a molding die having a smooth surface and good releasability can be produced. Ni-Cr-Al having high hardness and high corrosion resistance
For example, when tableting raw materials that contain highly corrosive substances such as acidic powder, the progress of corrosion of the pestle and die due to contact with the highly corrosive substances is greatly suppressed. be able to. Therefore, it is possible to suppress a decrease in releasability (for example, powder separation) associated with corrosion of the surface of the pestle or mortar, and further a decrease in strength, and it is possible to stably form tablets over a long period of time. Become. As a result, it is possible to improve the tableting yield and reduce the molding cost.

[Example]
(Examples 1-5, Comparative Examples 1-2)
A raw material consisting of 38% by mass of Cr, 3.8% by mass of Al, and the balance Ni was mixed and melted to prepare a molten raw material.

  Next, the ingot was adjusted to the cylindrical ingot and mold temperature shown in Table 1.

A round bar having a diameter of 35 mm was formed by hot forging and hot rolling. Each of these Ni—Cr—Al-based alloy materials was held at 1000 to 1300 ° C. for 2 hours and then cooled with oil and subjected to solution treatment. Next, each Ni—Cr—Al-based alloy material after the solution treatment was cut so as to be 1% larger than the dimensions of the predetermined ridges (upper heel and lower heel).

  The hardness of each Ni—Cr—Al alloy material after solution treatment is as shown in Table 1.

Next, each Ni-Cr-Al alloy material subjected to rough processing is subjected to 650 to 70 using a vacuum heat treatment furnace.
After holding at 0 ° C. for 4 to 10 hours, it was cooled to room temperature.

Thereafter, the molding surface of the punch and the surface used as the mortar of the mortar were polished so as to have a surface roughness Ra of 0.5 μm.

Comparative Example 1 was prepared with an ingot size that was 200 mm away from the cooling surface of the mold, and Comparative Example 2 was prepared with a mold that did not meet the manufacturing conditions, such as being performed at room temperature (25 ° C.) without preheating the mold temperature.

The measurement of each parameter was performed by the method described above by selecting a portion subjected to polishing.

As can be seen from the table, the Ni—Cr—Al alloy according to this example has a Cr concentration variation (
(Cr segregation) is suppressed, so the variation in planar hardness is small. As a result, the difference in surface irregularities when the polishing process is performed can be reduced.

(Examples 6 to 10)
Using the Ni—Cr—Al-based alloy composition shown in Table 3, tablet forming punches and mortars were produced.

Each ingot was subjected to hot forging and hot rolling, and then subjected to solution heat treatment at 1100 to 1250 ° C. to produce an alloy material. Next, forging, rolling, and cutting were performed so that the shapes shown in Table 4 were obtained, and then aging heat treatment was performed at 600 to 700 ° C. × 6 to 12 hours. Thereafter, the molding surface of the punch and the surface used as the mortar of the mortar were polished so as to have a surface roughness Ra of 0.2 μm. The same measurement as in Example 1 was performed for each pestle and mortar.

As can be seen from Table 4, also in the tablet forming punch and die using the Ni—Cr—Al alloy, Cr segregation can be reduced and a polished surface with small surface irregularities can be obtained. When a tablet was formed using this pestle and mortar, the release property was good.

DESCRIPTION OF SYMBOLS 1 ... Upper gutter 1a, 2a ... Molding part 2 ... Lower gutter 3 ... Dice 3a ... Dice hole (through hole)
10 ... Tablet molding machine

Claims (13)

N containing 30 to 45% by mass of Cr, 2 to 6% by mass of Al, the balance being Ni and inevitable impurities, and variation in Cr concentration of unit area 500 μm × 500 μm being 3% by mass or less
A tablet forming punch and die comprising an i-Cr-Al alloy. The tablet-forming pestle and die according to claim 1, wherein the Ni-Cr-Al-based alloy has an average hardness of Hv150 or higher and Hv200 or lower. The Ni—Cr—Al based alloy has a unit area of 500 μm × 500 μm with 25 small units 1
2. The small unit in which Cr concentration is shifted by 1.5% or more from the average unit area when divided into 00 μm × 100 μm is 3 or less (including 0) of 25 small units. The tablet forming punch and mortar according to claim 2. A tablet molding die and die produced by using the Ni-Cr-Al alloy according to claim 1 and polishing a part or all of the surface. The average hardness is Hv600 or more and Hv750 or less, and the hardness variation of the same plane is 2.
The tablet forming punch and mortar according to claim 4, which is 0% or less. 6. The tablet forming pestle and die according to claim 4 or 5, wherein the maximum value of the surface irregularities in the polished portion is 0.5 [mu] m or less. The tablet molding punch and die according to any one of claims 4 to 6, wherein an area of the polished portion is 10 mm ² or more. 8. The tablet forming pestle and die according to claim 4, wherein the surface roughness Ra is 1 [mu] m or less. A step of mixing 30 to 45% by mass of Cr, 2 to 6% by mass of Al, and mixing Ni and raw materials which are inevitable impurities, and preparing a Ni-Cr-Al alloy melt by melting;
Using the Ni-Cr-Al alloy molten metal to prepare an ingot having a shortest distance from the cooling surface of the mold of 120 mm or less;
Preparing a Ni—Cr—Al alloy having a hardness Hv of 150 to 200 by solution treatment of the ingot;
Machining the Ni-Cr-Al alloy;
Applying aging heat treatment at 500 to 750 ° C .;
A method for producing a tableting punch and die, comprising a step of performing a surface polishing process. The ingot size has a maximum distance from the cooling surface of 80 mm or less, and the manufacturing method of the tablet forming punch and die according to claim 9. The method for producing a tablet molding punch and die according to any one of claims 9 to 10, wherein casting is performed at a mold temperature of 50 ° C to 200 ° C. 12. The method for producing a tablet molding punch and mortar according to claim 9, wherein the thickness of the mold is 50 mm or more in the step of casting the ingot. 12. The method for producing a tablet molding punch and mortar according to claim 8, wherein the surface roughness Ra after the polishing process is 1 [mu] m or less.

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