JP2011001606A - Alloy material with high hardness, high corrosion resistance and high wear resistance, wear-resistant member using the same, and method for producing the wear-resistant member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Ni-Cr-Al alloy having reduced variation in a Cr concentration, to provide a wear-resistant member using the same, and to provide a method for producing the wear-resistant member.SOLUTION: The alloy material with high hardness, high corrosion resistance and high wear resistance is composed of, by mass, 30 to 45% Cr and 2 to 6% Al, and the balance Ni with inevitable impurities, and in the alloy material, the variation in the concentration of C in a unit area of 500 μm×500 μm is ≤3 mass%. The wear-resistant member uses the same. By the control of the size of an ingot and the temperature of a mold, Cr segregation caused by cooling non-uniformity is reduced.

Description

  The present invention relates to a high-hardness corrosion-resistant wear-resistant alloy material, a wear-resistant alloy member using the same, and a method for producing the same.

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. When a conventional mold made of alloy tool steel or the like is used to form such highly corrosive powder, 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 has a certain effect on the improvement of surface hardness etc., it will peel off easily, so it is possible to obtain a sufficient and stable improvement in wear resistance etc. Can not. For these reasons, it is desired to improve the corrosion resistance and wear resistance while maintaining the strength and hardness of the mold member.
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.

On the other hand, the application requiring corrosion resistance is not limited to a manufacturing apparatus such as the mold for corrosive powders described above, but includes, for example, chemical processing apparatuses, waste liquid and waste mud processing apparatuses, combustion apparatuses and peripheral parts thereof. Can be mentioned. In addition, corrosion-resistant steel such as stainless steel has been conventionally used for applications such as resin lenses and engineering plastics, such as resin molding dies, blades, and linear motion bearings, which mainly require corrosion resistance. However, corrosion-resistant steel such as stainless steel has insufficient strength and hardness, and cannot be used for applications that require particularly hardness and wear resistance.
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 die has characteristics such as high hardness and resistance to buckling against hot pressing at a temperature of 500 to 800 ° C. and a pressing pressure of 500 to 2000 kg / cm ² (50 to 200 MPa). In addition, corrosion resistance is obtained by 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, small pores are generated due to dropping of the precipitated carbide particles during polishing, and the polished surface is damaged due to the falling particles, and mirror finishing is 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. In the case of conventional materials, the polishing process takes more time than necessary to eliminate fine surface irregularities, and even if polishing takes time, it does not improve and sometimes becomes 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. In addition, there is a problem that a clean blade surface cannot be obtained when applied to a blade.
The present invention is for solving such problems, and by reducing Cr segregation, it eliminates a partial hardness difference and has a high hardness for eliminating fine irregularities on the polished surface when polishing is performed. An object is to provide a corrosion-resistant and wear-resistant alloy material, a wear-resistant member using the same, and a method for producing the same.

The high-hardness corrosion-resistant wear-resistant alloy material of the present invention contains 30 to 45% by mass of Cr, 2 to 6% by mass of Al, the balance is made of Ni and inevitable impurities, and has a variation in Cr concentration of unit area 500 μm × 500 μm. It is characterized by being 3% by mass or less. Moreover, it is preferable that the average hardness is Hv150 or more and Hv200 or less. Further, when a unit area of 500 μm × 500 μm is divided into 25 small units of 100 μm × 100 μm, 3 or less of 25 small units whose Cr concentration is shifted by 1.5% or more from the average of the unit areas (0 Preferably).
Further, such a high hardness corrosion resistant wear resistant alloy material is suitable for a wear resistant member formed by polishing a part or all of the surface. The wear resistant member preferably has 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 the polished part is 0.5 μm or less. Moreover, it is preferable that the area of the grind | polished location is 10 mm < ² > or more. Further, the surface roughness Ra is preferably 1 μm or less.

Moreover, the manufacturing method of the wear-resistant member of the present invention includes 30 to 45% by mass of Cr, 2 to 6% by mass of Al, and the remaining Ni and raw materials that are inevitable impurities are mixed and dissolved to form Ni-Cr. A step of preparing a molten Al alloy, a step of preparing an ingot having a minimum distance of 120 mm or less from the cooling surface of the mold using the molten Ni-Cr-Al alloy, and subjecting the ingot to a solution treatment to obtain a hardness A step of preparing a high-hardness corrosion-resistant wear-resistant alloy material having Hv of 150 to 200, a step of machining the high-hardness corrosion-resistant wear-resistant alloy material, a step of applying an aging heat treatment at 500 to 750 ° C., and a surface It comprises a step of applying a 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. 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.

  According to the present invention, since Cr segregation is reduced, a high-hardness corrosion-resistant wear-resistant alloy material that eliminates partial hardness differences and can reduce fine irregularities on the polished surface after polishing is provided. can do. In addition, since the wear-resistant member using such a high hardness corrosion-resistant wear-resistant alloy material has reduced fine irregularities, a flat polished surface can be obtained. Moreover, the manufacturing method of an abrasion-resistant member can obtain the abrasion-resistant member of this invention efficiently.

The figure which shows an example of the abrasion-resistant member (cutlery) of this invention. Sectional drawing of FIG. The figure which shows an example of an ingot. The figure which shows unit area 500 micrometers x 500 micrometers.

The high-hardness corrosion-resistant wear-resistant alloy material of the present invention contains 30 to 45% by mass of Cr, 2 to 6% by mass of Al, the balance is made of Ni and inevitable impurities, and has a variation in cross-sectional Cr concentration of unit area 500 μm × 500 μm. Is 3% by mass or less.
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).
The inevitable impurities indicate elements other than Ni, Cr, and Al, and the total content is preferably 1% by mass or less. Further, as a component other than Ni, Cr, and Al, it is selected from Zr (zirconium), Hf (hafnium), V (vanadium), Ta (tantalum), Mo (molybdenum), W (tungsten), and Nb (niobium). You may contain 0.2-2 mass% of at least 1 or more types of element. These elements are effective for improving the hardness of the alloy material.
Moreover, Mg (magnesium) is effective as a deoxidizer, and the addition amount is preferably 0.001 to 0.015% by mass. If it is less than 0.001% by mass, the effect of addition is insufficient, and if it exceeds 0.015% by mass, not only a further effect cannot be obtained but also the hardness may be lowered.

The present invention is characterized in that, in the Ni—Cr—Al alloy material 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. Further, the variation in Cr concentration is preferably as small as possible, and is preferably 2% by mass or less.
The variation in Cr concentration is performed by SEM-EDX method (X-ray spectroscopy using an energy dispersive X-ray spectrometer). Select an arbitrary measurement surface (a cut surface may be used for measurement) of a high-hardness corrosion-resistant wear-resistant alloy material or a wear-resistant member using the same, and average a unit area of 500 μm × 500 μm by the SEM-EDX method The amount of Cr is measured, 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 of the Cr concentration is, in the unit (100 μm × 100 μm), the maximum value (Cr mass%) − minimum value (Cr mass%) = Cr concentration variation (mass%).
In the present invention, the variation in Cr concentration is 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. Further, when Al is analyzed in the same manner, the variation in Al concentration is preferably 0.5% by mass or less, more preferably 0.1 to 0.3% by mass.
Further, the high hardness corrosion resistant wear resistant alloy material refers to a material obtained by subjecting an ingot after casting to plastic processing such as forging and rolling and subjecting it to a solution treatment. In addition, the wear-resistant member is a member obtained by processing an alloy material and subjecting it to an aging heat treatment, or a member subjected to polishing.

  In addition, when the unit area of 500 μm × 500 μm is divided into 25 small units of 100 μm × 100 μm, the Cr concentration is shifted by 1.5% or more from the average of the unit area, and 3 or less of the small units are 25 or less. It is preferable. 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. FIG. 4 shows a diagram in which a unit area of 500 μm × 500 μm is divided into 25 small units of 100 μm × 100 μm. 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, the Cr concentration is 3 or less (including 0) of 25 small units having a deviation of 1.5% or more from the average of the unit areas.

The high hardness corrosion resistant wear resistant alloy material preferably has an average hardness of Hv150 to 200. In particular, it is preferable that the hardness of the alloy material obtained by forging and rolling the ingot after casting and performing solution heat treatment is in the range of Hv150 to 200. If it is this range, it will be easy to adjust the average of the hardness after an aging heat processing in the range of Hv600-750.
In order to make a wear-resistant member using a high-hardness corrosion-resistant wear-resistant alloy material, the shape is adjusted by performing machining such as forging, rolling, and punching. Next, an aging heat treatment is applied to improve the hardness. Since Cr segregation is reduced in the present invention, the average hardness is Hv600 or higher and Hv750 or lower, and the hardness variation can be 2.0% or less.
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, as for hardness measurement locations, if there are polished locations, any five locations are selected from the polished portion (polished locations), and the hardness Hv is measured at each location.

  In the present invention, since the Cr concentration variation of the alloy material is proposed, the hardness variation can be further reduced to 2.0% or less after the hardness of the wear resistant member is increased to Hv600 or more and Hv750 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 was not controlled, the surface unevenness of the polished surface was as large as 1.5 μm or more even with the same Ra of 1 μm. 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. When such a polished surface is used, for example, in a mold for producing a molded product, the surface unevenness of the molded product becomes large, and there is a problem that a clean molded product cannot be formed or the molded product has insufficient releasability. By reducing Cr segregation as in the present invention, the surface unevenness can be reduced to 0.5 μm or less, so that even when used in a mold for producing a molded product, a mold having a smooth surface and good releasability can be produced. . Moreover, when it uses for a cutter, the surface is smooth and can obtain a sharp cutting surface (blade edge).

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, even if it is a grinding | polishing process part with a large area of 10 mm < ² > or more, the flat surface is obtained. Therefore, even if it is a wide wear-resistant member having a short side length of 4 mm or more, there is no polishing unevenness and a uniform mirror surface can be obtained.
Such an alloy material can be applied to various wear-resistant members. In particular, it is suitable for a wear-resistant member in which a part or all of the surface thereof is polished. Further, since Ni—Cr—Al alloy is a material exhibiting high hardness and high corrosion resistance, it can be applied to fields requiring such characteristics. Examples of wear-resistant members include molds, mortars, and molds for compressing raw materials such as powders and granules to form tablets for pharmaceuticals, quasi-drugs, cosmetics, agricultural chemicals, feeds, foods, etc. Etc. In addition, there are surgical scalpels, scissors, and general-purpose blades. Moreover, it is suitable for surgical instruments such as tweezers and surgical scalpels by utilizing the corrosion resistance. In any field, Ra 1 μm or less, further 0.5 μm or less is required.

  FIG. 1 shows a cutter as an example of the wear-resistant member of the present invention. In the figure, 1 is a blade, 2 is a blade edge, and 3 is a blade body. FIG. 2 is a cross-sectional view of the blade edge of FIG. 1 viewed from the thickness direction. The blade edge 2 is a place where the polishing process is performed, and the blade main body is a place where the polishing process is not performed.

Next, the manufacturing method of the wear resistant member of the present invention will be described. Although the manufacturing method of the abrasion-resistant member of this invention is not specifically limited, The following are mentioned as a method for obtaining efficiently.
The manufacturing method of the wear-resistant member of the present invention comprises 30 to 45% by mass of Cr, 2 to 6% by mass of Al, the remainder being mixed with Ni and raw materials that are inevitable impurities, and melted to be Ni-Cr-Al A step of preparing a molten alloy, a step of preparing an ingot having a maximum distance of 120 mm or less from the cooling surface of the mold using the molten Ni-Cr-Al alloy, and a hardness Hv by solution treatment of the ingot. A step of preparing a 150 to 200 high hardness corrosion resistant wear resistant alloy material, a step of machining the high hardness corrosion resistant wear resistant alloy material, a step of aging heat treatment at 500 to 750 ° C., and a surface polishing process It comprises the process of giving.
First, Cr, Al, Ni as raw materials and, if necessary, an element selected from Zr, Hf, V, Ta, Mo, W, and Nb are 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. 3 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. Further, casting is preferably performed at a mold temperature of 50 ° C. or higher and 200 ° C. or lower. By adjusting the ingot size and mold temperature, the ingot can be rapidly cooled to eliminate uneven cooling. By carrying out the rapid cooling process, the uniformly mixed raw material melt can be made into an ingot as it is, so that Cr segregation in the ingot can be eliminated.

In the production method of the present invention, it is important to control so as not to cause uneven cooling, and in particular, to manage the cooling process so as to prevent partial cooling. 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 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 wear-resistant member to be used finally is processed to a shape close thereto.

  Next, the process of performing an aging heat processing at 500-750 degreeC is performed. The heat treatment time is preferably 1 to 15 hours. The aging heat treatment is preferably a vacuum heat treatment in an argon atmosphere in order to prevent contamination such as oxidation. It is also effective to perform pretreatment heating before aging heat treatment as described in Patent Document 3 in order to eliminate unaged structures. 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 what consists of heating in (b), or what consists of holding for at least 0.5 hours in the temperature range of 400-500 ° C. Here, when the temperature increase rate in the above (a) is slower than 100 ° C./h, the characteristics appear, but it takes too much time for the treatment, which is not preferable in production. On the other hand, if the temperature rising rate is excessive such that it exceeds 500 ° C./h, the temperature distribution may become non-uniform or the volume shrinkage accompanying the precipitation may become excessive, leading to crack generation. When the holding time in (b) is less than 0.5 hour, 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 is performed at a place where a mirror finish with a surface roughness Ra of 1 μm or less and further Ra 0.5 μm or less is required. For example, in the case of a mold (mold), the inner surface is polished. Moreover, if it is a blade, the part which functions as a blade will be grind | polished. Examples of the polishing method include polishing using a diamond grindstone, such as polishing polishing. Moreover, you may perform cutting etc. as needed.

[Example]
(Examples 1-5, Comparative Examples 1-2)
A raw material powder composed of 38% by mass of Cr, 3.8% by mass of Al, and the balance Ni was mixed and melted to prepare a raw material melt.
Next, the ingot was adjusted to the cylindrical ingot and mold temperature shown in Table 1.
Each ingot was subjected to hot forging and hot rolling, and then subjected to solution heat treatment at 1000 to 1300 ° C. in an argon atmosphere using a vacuum heat treatment furnace to produce an alloy material.
Next, the obtained alloy material was subjected to forging, rolling, and cutting to produce a plate material having a length of 30 mm × width of 5 mm × thickness of 1 mm. The tip (2 mm long × 5 mm wide) was pressed and bent so as to have a triangular cross section. Then, after aging heat treatment was performed in an argon atmosphere at 650 to 700 ° C. for 4 to 10 hours using a vacuum heat treatment furnace, the tip portion was polished so as to have a mirror surface with a surface roughness Ra of 0.5 μm. Note that the tip portion is a portion that becomes a cutting edge.
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 wear-resistant member (blade) according to the present example suppresses variation in Cr concentration (Cr segregation), and thus 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 alloy composition shown in Table 3, a punch was produced as a mold for tableting.
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 surface used as the molding surface of the ridge was polished so as to have a surface roughness Ra of 0.2 μm. The same measurement as Example 1 was performed about each cage.

  As can be seen from Table 4, it can also be used for molds. Even in a wide wear-resistant member, Cr segregation can be reduced. Therefore, a polished surface with small surface irregularities can be obtained. When this tablet was used to mold a tablet, the releasability was good.

DESCRIPTION OF SYMBOLS 1 ... Blade 2 ... Cutting edge 3 ... Blade body part

Claims (13)

High hardness characterized by 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 Corrosion-resistant and wear-resistant alloy material. The high hardness corrosion-resistant wear-resistant alloy material according to claim 1, wherein the average hardness is Hv150 or more and Hv200 or less. When a unit area of 500 μm × 500 μm is divided into 25 small units of 100 μm × 100 μm, the Cr concentration is shifted by 1.5% or more from the average of the unit area, and 3 or less of 25 small units (including 0) The high-hardness corrosion-resistant wear-resistant alloy material according to any one of claims 1 and 2. A wear-resistant member manufactured using the high-hardness corrosion-resistant wear-resistant alloy material according to any one of claims 1 to 3, and having a part or all of the surface polished. The wear-resistant member according to claim 4, wherein the average hardness is Hv600 or more and Hv750 or less, and the hardness variation of the same plane is 2.0% or less. The wear-resistant member according to claim 4 or 5, wherein the maximum value of the surface irregularities of the polished portion is 0.5 µm or less. The wear-resistant member according to any one of claims 4 to 6, wherein an area of the polished portion is 10 mm ² or more. The wear-resistant member according to any one of claims 4 to 7, wherein the surface roughness Ra is 1 µm 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;
A step of solution-treating the ingot to prepare a high-hardness corrosion-resistant wear-resistant alloy material having a hardness Hv of 150 to 200;
Machining the high hardness corrosion resistant wear resistant alloy material;
Applying aging heat treatment at 500 to 750 ° C .;
A method for producing a wear-resistant member, comprising a step of performing surface polishing. The method for producing a wear-resistant member according to claim 9, wherein the ingot size has a maximum distance from the cooling surface of 80 mm or less. The method for producing a wear-resistant member according to any one of claims 9 to 10, wherein casting is performed at a mold temperature of 50 ° C to 200 ° C. The method for producing a wear-resistant member according to any one of claims 9 to 11, wherein, in the step of casting the ingot, the thickness of the mold is 50 mm or more. The method for producing a wear-resistant member according to any one of claims 8 to 11, wherein the surface roughness Ra after polishing is 1 µm or less.

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