JP4207165B2 - High hardness stainless steel excellent in mirror finish and method for producing the same - Google Patents

Description

  The present invention improves the specularity and hardness of stainless steel with excellent corrosion resistance, and is used for ultra-mirror surface molding of plastics and glass parts that require extremely high surface accuracy, such as optical disks and optical lenses. The present invention relates to a stainless steel that is most suitable for a corrosion-resistant wear mold and the like, and a manufacturing method thereof.

  Conventionally, in the field of optical disk resin molding such as CD and DVD media, the field of resin or glass molding for optical lenses, and the field of resin molding for optical components such as liquid crystal light guide plates, SUS420J2 of JIS steel grade or similar stainless steel is used. Cutting and grinding molds were used. In cases where extremely high accuracy is required, such as plastic optical parts, after the amorphous steel such as Ni-P is applied to the SUS420J2-equivalent steel, the molded surface may be finished by cutting with a diamond tool. In some cases, copper alloys with few impurities were similarly cut and finished.

On the other hand, there are SKD11 type and SUS440C type as materials that achieve both corrosion resistance and hardness. For example, a precipitation hardening stainless steel having a C content of 0.08% by mass or less (hereinafter referred to as%) and containing 2.0% to 5.0% Si and 6.0% to 10.0% Cr has been proposed. . An improved steel aiming at achieving high hardness by adding an appropriate amount of Mn, Ni, Mo, Cu, Nb, Ta, Ti, Co to this stainless steel has been proposed (Patent Document 1). .
JP 2001-107194 A

  Among the molds for molding optical disks and optical components described above, those made of SUS420J2 are advantageous in that a certain level is obtained in terms of corrosion resistance and high hardness, but the achieved hardness is limited to 55 HRC at most. There is a problem that the wear resistance is insufficient when the molding shots in use are stacked. In the case of applying Ni-P plating or a copper alloy, the hardness is further low, which is disadvantageous for long-term stable forming.

  In addition, SUS420J2 level corrosion resistance is not sufficient for long-term mass production in the case of molds for optical disk molding that requires water cooling and plastic molding that generates corrosive gas during use. there were. Furthermore, since SUS420J2 is accompanied by large chromium carbide precipitates on the order of microns in the structure, there is a problem that it is difficult to obtain a strict smooth mirror surface on the molding surface. This problem becomes a big problem when putting the next generation high density optical disk aiming at the average surface roughness of the sub-nano order into practical use.

  On the other hand, SKD11-based and SUS440C-based molten steels or powdered steels that are conventionally used for applications that require high hardness (58HRC or higher) and corrosion resistance are also used for optical disk molding that requires water cooling, and corrosive gas is used during use. In molds for plastic molding that occur, corrosion resistance is not sufficient for long-term mass production. In addition, since these materials contain hard alloy carbides, there is room for improvement when the super mirror finish is achieved.

  And although the improved steel described in Patent Document 1 is a material superior to the conventional steel in terms of both high hardness and high corrosion resistance, the maximum hardness achieved is a small steel piece called a round bar having a diameter of 20 mm. Even when water cooling (rapid cooling) advantageous for increasing the hardness is adopted as the cooling condition at the time of the solution treatment, the limit is around 58HRC in the subsequent aging treatment. If it is an optical disk or mold for molding optical components that is actually used, it is difficult to handle with such a small steel piece, and the cooling conditions during the solution treatment are also slow cooling such as air cooling to suppress heat treatment strain. Is desirable. In the case of the improved steel of Patent Document 1, if the above-described actual mold conditions are applied, the achieved hardness is less than 58 HRC.

  In addition, although the specularity achieved by the improved steel described in Patent Document 1 is superior to that of conventional steel, many Laves phases that are softer than carbides are precipitated in the structure. Obtaining a structure with high hardness is an important requirement for achieving excellent specularity. Therefore, in the field where super-mirror finish for optical disk and optical component molding is required, the improved steel of Patent Document 1 There is room for further improvement.

  The object of the present invention is to solve the above-mentioned problems, and particularly excellent in mirror finish, which is optimal for the field of tools and parts such as special molds for molding plastic or glass parts that require extremely high surface accuracy. Another object of the present invention is to provide a high hardness stainless steel and a method for producing the same.

  As a result of studying the above-mentioned problems, the present inventor has developed a special mold material as described above, which requires corrosion resistance, high hardness, and a molding surface having a very smooth mirror surface that is unmatched in other mold applications. Therefore, it was found that the stainless steel added with the regulation of the amount of Mo and the optimum amount of Si was the most suitable for the application. And even when applying slow cooling conditions such as air cooling to the cooling of the solution treatment, we found a component composition that can achieve a hardness as high as 61 HRC if it is a quenching condition of 59 HRC or higher, which is water cooling. The inventors have found that obtaining by the consumable electrode type remelting method is optimal for exhibiting the effects of the present invention, and have reached the present invention.

That is, in the present invention, by mass%, C: 0.01 % or less, Si: 1.5 to less than 3.0 %, Mn: 3.0% or less, Cr: 6.0 to 12.0%, Ni: 4 0.0-10.0%, Co: 10.0% or less, Cu: 6.0% or less, Ti: 0.5-3.0 %, Al: 0.07-2.0 % , Mo Is a high-hardness stainless steel excellent in mirror finish, characterized in that N is restricted to 1.0% or less, N is 0.01% or less, and the balance is made of Fe and inevitable impurities. Preferably, Si: 2.0 to less than 3.0% or Mo is further restricted to 0.5% or less. You may contain 1.0% or less Nb or 1.0% or less Ta, or 0.1% or less Zr. More preferably, it is a stainless steel having a hardness of 59 HRC or more.

And this invention is obtained by performing a consumable electrode type remelting method, C: 0.01 % or less, Si: 1.5 to less than 3.0 %, Mn: 3.0% or less, Cr, : 6.0 to 12.0%, Ni: 4.0 to 10.0%, Co: 10.0% or less, Cu: 6.0% or less, Ti: 0.5 to 3.0%, Al: Containing 0.07 to 2.0 % , Mo is controlled to 1.0% or less, N is controlled to 0.01% or less, and the balance is made of Fe and unavoidable impurity stainless steel with a hardness of 59 HRC or more. It is a method for producing a high-hardness stainless steel excellent in mirror finish, characterized by tempering. The stainless steel may contain 1.0% or less Nb, or 1.0% or less Ta, or 0.1% or less Zr. Preferably, the tempering is performed at 1000 to 1150 ° C. and aging at 400 to 550 ° C.

  According to the present invention, it is possible to drastically improve the super-mirror finish and wear resistance of high hardness stainless steel having excellent corrosion resistance. This technology is indispensable for the practical application of long-term stable molding of plastic or glass parts that require precision.

  As described above, an important feature of the present invention is stainless steel to which an optimum amount of Si is added in addition to excellent corrosion resistance, and further, the type and optimum amount of other constituent elements, particularly the effect of Mo. As a result of revising the stainless steel, high hardness, super mirror finish, and wear resistance have been greatly improved, and an optimum manufacturing method for this stainless steel has also been found.

First, the component composition of the present invention will be described.
As described above, as a technique for increasing the hardness of stainless steel, it is difficult to obtain super-specularity when a precipitation action of hard carbide in the structure is employed. Therefore, in the stainless steel of the present invention, an intermetallic compound that is moderately softer than carbide is finely precipitated in the structure, and the carbide is reduced and refined to obtain ultra-specularity and high hardness. . For this reason, it is important to adjust the amount of C in stainless steel. By controlling C to 0.01 % or less, hard carbides in the steel structure are reduced, and the precipitation size is suppressed to the submicron order. Finishability can be realized . Good Mashiku is less than 0.01%.

Si is a main element that imparts strength to the stainless steel of the present invention. And it is an essential element for realizing mirror finish, which is important for application to the mold application assumed by the present invention. That is, excellent mirror finish is obtained by contributing to the precipitation strengthening mechanism of forming a G phase together with Cr, Ni, Co and Ti without relying on the conventional precipitation strengthening mechanism by carbide. Si dissolved in the matrix also has an effect of improving corrosion resistance (particularly sulfuric acid resistance). If it is less than 1.5%, the effect is insufficient, but if it is 3.0 % or more, a large Laves phase on the order of several tens of microns is precipitated, which itself deteriorates the mirror finish, and Si and Since other strengthening elements are also taken into the Laves phase, adding them in excess has no effect. Therefore, in the present invention, it is defined as 1.5 to less than 3.0 %. Preferably it is 2.0 to less than 3.0%.

  Mn acts as a deoxidizer for steel and is preferably contained in an amount of 0.05% or more. However, if it is too much, the amount of austenite in the structure increases excessively, making it difficult to obtain a predetermined hardness. Therefore, Mn is made 3.0% or less. Preferably it is 0.8% or less.

  Cr is an indispensable component for ensuring the corrosion resistance of stainless steel, and considering the use of the mold of the present invention, the corrosion resistance is insufficient at less than 6.0%. Moreover, G phase is formed with Si, Ni, Co, and Ti, and it contributes to precipitation strengthening. However, if it exceeds 12.0%, it becomes difficult to obtain a predetermined hardness, desirably 59 HRC or higher. Therefore, Cr is set to 6.0 to 12.0%.

  Ni is an element that imparts corrosion resistance to steel and has the effect of transforming the phase transformation of the steel into a desirable form in balance with Cr, that is, from austenite single phase to low carbon martensite single phase during solution heat treatment cooling. is there. And G phase is formed with Si, Cr, Co, and Ti, and it contributes to precipitation strengthening. However, if the amount is too large, the amount of austenite increases too much, and it becomes difficult to obtain a predetermined hardness. Therefore, Ni of the present invention is 4.0 to 10.0%.

  Co is an important element that contributes to precipitation strengthening by forming a G phase together with Si, Cr, Ni, and Ti in addition to improving corrosion resistance. However, since excessive content impairs machinability, it is made 10.0% or less.

  Cu contributes to precipitation hardening and improves corrosion resistance during aging after the solution treatment. However, since a large amount impairs hot workability, it is an important element for regulatory management. Although it is 6.0% or less in the present invention, it is preferably 2.0% or less in order to cope with the material size required for the actual mold.

  Ti is one of the main elements that contribute to age hardening during hardness tempering by solid solution and aging treatment. That is, it is an important element that forms a G phase together with Si, Cr, Ni, and Co and contributes to precipitation strengthening. Therefore, the content is 0.5% or more. However, if it is contained in a large amount, the toughness is lowered, and furthermore, a large Laves phase on the order of several tens of microns is increased, which itself deteriorates the mirror finish and Ti and other strengthening elements are also taken into the Laves phase. There is no effect even if added to. Furthermore, excess Ti forms carbides, nitrides, and the like, which adversely affects mirror finish. Therefore, it is 0.5 to 3.0% in the present invention. Desirably, it is 1.0 to 2.5%.

Al is an element that acts as a deoxidizer for steel. Namely, strengthening mechanism to which the present invention is adopted is not rely on the introduction of hard carbide, since the carbide conversely it is necessary to reduce the possible adverse effects on the mirror surface finish properties, C 0.01% below, preferably Restrict to less than 0.01%. Accordingly, deoxidation with C cannot be performed, so deoxidation with Al is effective. However, since much Al content reduces toughness, Al of the present invention is made 0.07 to 2.0 % . Desirably, it is 0.07 to 0.5 % .

In addition, Al, on the other hand, is feared to deteriorate the mirror finish of steel as a result of the formation of Al ₂ O ₃ and Al / Mg composite oxides. For example, after deoxidation, Al is removed from the molten metal as much as possible. It is desirable to do. Alternatively, Al deoxidation itself can be omitted by positively introducing a consumable electrode type remelting method.

  Mo is an element that has been conventionally added as an element that improves corrosion resistance and contributes to age hardening during solidification and tempering by aging treatment. However, as Mo is added, a large Laves phase on the order of several tens of microns increases, which degrades the mirror finish. And, in addition to Mo, other strengthening elements are also taken into the Laves phase, which adversely affects the increase in hardness. Therefore, in the present invention, it is important to limit Mo to 1.0% or less, preferably 0.5% or less, and more preferably less than 0.4%.

  N forms nitrides and carbonitrides with Ti and the like, and adversely affects the mirror finish. Therefore, N must be regulated to 0.01% or less. Desirably, it is regulated to 0.005% or less, and more desirably to 0.003% or less.

What is particularly important in the component composition of the present invention is the combined management of Si and Mo, in which the contained Si is managed in a low region and Mo is regulated. In other words, by reviewing the effect of Mo, limiting Mo to 1.0% or less, and finding the optimum amount of Si amount range of 1.5 to less than 3.0 %, precipitation of a large Laves phase Can be suppressed. And even if water cooling or oil cooling is not applied to the cooling conditions of the solution treatment, it is possible to achieve sufficient use hardness under the air cooling conditions, specifically high hardness of 59 HRC or more, and to reduce the heat treatment distortion in question. Can do. Naturally, water cooling or oil cooling may be applied. In this case, even higher hardness reaching 61 HRC can be achieved.

  The stainless steel of the present invention may contain Nb and / or Ta as necessary. Nb has the effect of increasing the aging hardness of stainless steel, but if it is contained excessively, a large Laves phase on the order of several tens of microns will increase, and the mirror finish will deteriorate, and Nb and other strengthening elements will be removed. Therefore, even if added excessively, there is no effect. Therefore, if added or contained, 1.0% or less is desirable. More desirably, it is 0.5% or less. In addition, in order to acquire said effect, containing 0.1% or more is desirable.

  Ta, like Nb, has the effect of increasing the aging hardness of stainless steel, but too much content also adversely affects the mirror finish. Therefore, if added or contained, 1.0% or less is desirable. More desirably, it is 0.5% or less. In addition, in order to acquire said effect, containing 0.1% or more is desirable.

Alternatively, the stainless steel of the present invention may contain Zr as necessary. Zr has an effect to prevent the occurrence of pinholes by replacing causing pinholes _as Al ₂ O ₃ and Al / Mg composite oxide when the mirror-finished to ZrO _2, excessive content of In this case, a large Laves phase on the order of several tens of microns and Zr inclusions increase, and the mirror finish is also deteriorated. Therefore, even if added or contained, 0.1% or less is desirable. The content is more preferably 0.08% or less, but in order to obtain the above effect, the content is preferably 0.01% or more.

  Further, as described above, it is desirable that the stainless steel of the present invention has a hardness of 59 HRC or more, and there is an important feature in that this is achieved. A hardness of 59 HRC or higher makes it difficult to scratch during rough polishing of mirror polishing, and facilitates mirror finishing and at the same time improves wear resistance. In order to achieve such high hardness, the component composition of the stainless steel is an important factor. Therefore, if the stainless steel of the present invention is applied to a molding die for products that require extremely high surface accuracy, such as plastics and glass parts, the hardness is tempered, and cutting or grinding / polishing is performed. Molded surfaces that have been machined such as lapping have excellent super-mirror finish and wear resistance during molding.

  And in addition to said component composition which comprises the stainless steel of this invention, it is desirable for it to be obtained by the consumable electrode type remelting method, for example. That is, the stainless steel of the present invention obtained by performing a consumable electrode type remelting method such as a vacuum arc remelting method (VAR) or an electroslag remelting method (ESR) is mirror-finished. Non-metallic inclusions such as alumina that cause pinholes during finishing are reduced, and more stable ultra-mirror finish can be realized. The consumable electrode type remelting method may be performed once or a plurality of times, and the steel ingot obtained thereby may be hot-worked by forging or rolling.

  In order to refining the steel ingot of the composition of the present invention obtained above to a high hardness stainless steel of 59HRC or higher with excellent mirror finish, after performing a solution treatment at 1000 to 1150 ° C. It is desirable to perform an aging treatment at 400 to 550 ° C. In the solution treatment at less than 1000 ° C., the Laves phase does not dissolve, which adversely affects the mirror finish and the increase in hardness. In the solution treatment at more than 1150 ° C., the crystal grains become coarse and the toughness decreases. In addition, since a precipitation hardening phase does not precipitate in an aging treatment of less than 400 ° C., it is difficult to obtain a hardness of 59 HRC or more. . In the tempering of the present invention, after the solution treatment, the aging treatment may be performed after the sub-zero treatment.

In showing the effect of the stainless steel of this invention, in this Example 1, it evaluates at the time of applying the water cooling conventionally applied to the cooling conditions of the solution treatment. First, a steel ingot obtained by vacuum induction furnace melting (sample No. 4 is vacuum arc remelting) is hot-worked, and a chemical component (mass%) shown in Table 1 consisting of the balance Fe and inevitable impurities ( The dimensions were 15 × 15 × 30 mm). These samples were subjected to a tempering treatment of a solution treatment (1100 ° C.), a sub-zero treatment (−78 ° C.), and an aging treatment (480 ° C.) to evaluate the hardness achieved. Sample No. No. 10 is a large sample obtained by hot working a steel ingot obtained by vacuum arc remelting to a diameter of 200 mm and tempering a solid solution treatment (1100 ° C.) and an aging treatment (490 ° C.) . This sample is used for evaluation in Examples 2 and 3 described later.

  Here, the cooling during the above-mentioned solution treatment was performed by adjusting to a cooling rate of 15 minutes of semi-cooling, separately from water cooling. Semi-cooling refers to the time required for cooling from the solution treatment temperature to half the temperature of (solution treatment temperature + room temperature). And in this Example 1, the condition of semi-cooling 15 minutes corresponding to the cooling rate when the steel material having a diameter of 300 mm when the stainless steel of the present invention is applied to the above-described actual mold is oil-cooled also. Applied. Table 2 shows the obtained hardness. Sample No. As for 1, 2, 3 and 12, the microstructure after aging treatment is shown in FIGS.

  Then, in order to evaluate the mirror finish of each sample with adjusted hardness, mirror finishing was performed under the conditions (alumina polishing finish) that assumed mirror polishing applied to the molding surface processing of optical disc molds. The specularity of the processed surface was evaluated. The evaluation of the specularity is based on the specularity (○) of the specularity of the SUS440C equivalent powder steel (59.8HRC) exhibiting good specularity (micrograph magnified photograph [× 900 times] is shown in FIG. 5). Those exhibiting superior specularity were marked with ““ ”(FIG. 6), and those with slight inferiority but without any difficulty in use were marked with“ Δ ”(FIG. 7). In addition, in this preparation sample, there was no sample which was inferior in specularity so that it was hard to endure use. The results are shown in Table 3.

  Sample No. in Table 1 1 to 9 are steels satisfying the present invention. Nos. 5 and 6 are added with Nb and Ta, respectively. These samples have a combined effect of Si low-frequency management and Mo regulation, so that the cooling conditions for the solution treatment are 60 HRC or more even when semi-cooled for 15 minutes. The hardness reached about 61 HRC at 2, 3 and 4, and excellent high hardness characteristics were obtained. Furthermore, sample no. When the cooling condition of the solid solution treatment No. 9 was water-cooled, a hardness of 61.4 HRC was obtained. In addition, sample Nos. To which Nb and Ta were added 5 and 6, when the solution treatment temperature was 1150 ° C., sample No. Hardness equivalent to 2, 3, 4 is obtained. The steel satisfying the present invention is shown in FIGS. By adopting the simultaneous management of Si and Mo of the present invention as shown in 1, 2 and 3 microstructures, the precipitation of large Laves phase is almost suppressed, and as shown in Table 3, the super mirror finish Excellent results were also obtained.

  Sample No. No. 12 is high in Si and Mo, but the cooling condition of the solution treatment is about 57 HRC when the cooling is semi-cooled for 15 minutes, and the hardness of 59 HRC cannot be achieved even with water cooling. Furthermore, even when the solution treatment temperature is increased to 1150 ° C. and water cooling is performed, it is the limit to reach 59HRC. Although the mirror finish is superior to conventional steels such as SUS420J2, many large Laves phases on the order of several tens of microns are precipitated as shown in Fig. 4, and as shown in Table 3, super mirror finish is achieved. Inhibits sex.

  Sample No. 13 and 14 are sample Nos. Although 12 Si was controlled low, Mo is still high. Sample No. No. 13 is low in Si and relatively small in Ti, so the hardness is less than 57 HRC even if the cooling condition of the solution treatment is water cooling. Sample No. 14 is Sample No. By increasing Ti to 13, the cooling condition of the solution treatment satisfies 59 HRC in the semi-cooled 15 minutes, can achieve 60 HRC in the water cooling, and sufficiently satisfies the application to the actual mold in hardness. Obtained. However, with regard to the mirror finish, the sample No. Although the deposition of Laves phase larger than 12 could be suppressed, it still contained a large amount of Mo, which is insufficient to satisfy the super mirror finish.

Next, in the present Example 2, the case where air cooling is applied to the cooling conditions of the solution treatment is evaluated. This is an effective cooling condition for suppressing heat treatment distortion in the manufacture of a real mold. Sample No. in Table 1 2 and No. In No. 3, a solution treatment (1100 ° C.) was performed, followed by an aging treatment (480 ° C.). Sub-zero processing was not performed. And as for the cooling conditions of the solution treatment, in addition to the semi-cooled 15 minutes assuming oil cooling in the real mold (diameter 300 mm) as described above, the diameter of 200 mm is also applied to the real mold. A semi-cooled 70 minute condition corresponding to a slow cooling rate when the steel was air-cooled was applied. Table 4 shows the hardness in each case. And sample No. which actually has a diameter of 200 mm. For a 1 0, since the application of the air to the cooling conditions of the solution treatment, a cooling rate equivalent 70 minutes semi-cold.

  And in order to evaluate the mirror finish of each sample which adjusted hardness, the mirror finish similar to Example 1 was given and the mirror finish of the processed surface was evaluated. The evaluation of the specularity is based on the same evaluation method as in Example 1, with the specularity of SUS440C equivalent powder steel (59.8HRC) in Example 1 as the reference “◯”. The results are shown in Table 5.

From Tables 2 and 4, Sample No. satisfying the present invention was obtained. Nos. 2 and 3 were able to achieve a hardness of 59 HRC or higher without sub-zero treatment. Furthermore, even when the cooling rate was less than air cooling (semi-cooled 70 minutes) in the solution treatment when assuming a real mold, a result that a hardness of 59 HRC or higher could be achieved was obtained. And even if it is these microstructures, sample No. of FIGS. The deposition of the Laves phase on the order of several tens of microns, similar to 1 to 3, is suppressed, and as shown in Table 5, the super mirror finish is also achieved. Sample No. 10 was actually applied with air cooling, but a hardness of 60 HRC or higher was obtained. Also, with regard to the microstructure, precipitation of the Laves phase on the order of several tens of microns was suppressed, and as shown in Table 5, super mirror finish was also achieved.

In Example 3, the sample No. 1 satisfying the present invention was used. 10 (60.5HRC) and as a comparative material, SUS440C equivalent powder steel (59.9HRC) with good hardness and mirror finish was evaluated for corrosion resistance. Corrosion resistance was evaluated by immersing the salt spray test method of JIS-Z-2371 and a sample (diameter 10 mm, length 20 mm) in 200 ml of 1% by weight acid (hydrochloric acid, sulfuric acid, nitric acid) for 24 hours. Corrosion weight loss test was conducted in which the weight loss was reduced. In Example 3, the rating number method (JIS-Z-2371-Appendix 1; test piece effective surface was used to evaluate the size and number of corrosion defects with a number of 0 to 10 in which the effective surface of the test piece was 360 mm ^2. Table 6 shows the results of the salt spray test and Table 7 shows the results of the corrosion weight loss test evaluated using the method. .

  According to the results of the salt spray test in Table 6, the SUS440C equivalent powder steel has a corrosion area ratio of more than 25% after 5 hours of salt water spray, and exceeds 50% after 24 hours. However, sample no. It can be seen that No. 10 is not corroded at all even after 240 hours and has excellent corrosion resistance. In the corrosion weight loss test of Table 7, sample No. No. 10 is clearly corrosive resistant to each acid as compared with SUS440C equivalent powder steel.

  The stainless steel of the present invention having a high degree of corrosion resistance, specularity, and high hardness is a PPS resin containing a reinforcing agent such as glass fiber that requires similar characteristics in addition to a mold for molding optical disks and optical lenses. It can also be applied as a so-called super engineering plastic molding die. It can also be applied to cutting tools, tablet punches, precision machine parts, and the like.

It is a microscope picture which shows an example of the microstructure of this invention steel. It is a microscope picture which shows an example of the microstructure of this invention steel. It is a microscope picture which shows an example of the microstructure of this invention steel. It is a microscope picture which shows the microstructure of comparative steel. It is a microscope picture which shows the mirror-finishing surface (evaluation (circle)) of SUS440C equivalent powder steel. It is a microscope picture which shows an example of the mirror-finishing surface (evaluation (double-circle)) of this invention steel. It is a microscope picture which shows an example of the mirror surface processing surface (evaluation (triangle | delta)) of a comparative steel.

Claims (12)

C: 0.01 % or less, Si: 1.5 to less than 3.0 %, Mn: 3.0% or less, Cr: 6.0 to 12.0%, Ni: 4.0 to 10. 0%, Co: 10.0% or less, Cu: 6.0% or less, Ti: 0.5-3.0 %, Al: 0.07-2.0 % , Mo is 1.0% Below, N is restricted to 0.01% or less, and the balance consists of Fe and inevitable impurities, and is a high hardness stainless steel with excellent mirror finish. The high-hardness stainless steel with excellent mirror finish according to claim 1, wherein Si is 2.0 to less than 3.0% by mass%. The high-hardness stainless steel excellent in mirror finish according to claim 1 or 2, wherein Mo is regulated to 0.5% or less by mass%. The high-hardness stainless steel excellent in mirror finish according to any one of claims 1 to 3, wherein Nb is 1.0% or less by mass%. The high-hardness stainless steel excellent in mirror surface finish according to any one of claims 1 to 4, wherein Ta: 1.0% or less in mass%. The high-hardness stainless steel excellent in mirror finish according to any one of claims 1 to 5, wherein the mass% is Zr: 0.1% or less. The high-hardness stainless steel excellent in mirror finish according to any one of claims 1 to 6, wherein the hardness is 59 HRC or more. C: 0.01 % or less, Si: 1.5 to less than 3.0 %, Mn: 3.0% or less, Cr: 6.0 to 0.0% by mass% obtained by performing the consumable electrode type remelting method 12.0%, Ni: 4.0-10.0%, Co: 10.0% or less, Cu: 6.0% or less, Ti: 0.5-3.0 %, Al: 0.07-2 0.0 % is contained, Mo is controlled to 1.0% or less, N is controlled to 0.01% or less, and the balance is to refine Fe and inevitable impurities stainless steel to a hardness of 59 HRC or more. A manufacturing method of high hardness stainless steel with excellent mirror finish. The method for producing high-hardness stainless steel excellent in mirror finish according to claim 8, wherein the stainless steel is Nb: 1.0% or less in mass%. The method for producing high-hardness stainless steel with excellent mirror finish according to claim 8 or 9, wherein the stainless steel is Ta: 1.0% or less in mass%. The method for producing a high-hardness stainless steel excellent in mirror finish according to any one of claims 8 to 10, wherein the stainless steel is Zr: 0.1% or less by mass%. The tempering is performed at a solid solution treatment at 1000 to 1150 ° C and an aging treatment at 400 to 550 ° C, and the high hardness stainless steel having excellent mirror finish according to any one of claims 8 to 11 Manufacturing method.