Rolling device and manufacturing method for the same

Abstract

To provide a rolling device with high performance by using a material that has high non-magnetic properties, high corrosion resistance and high rigidity and of which workability and Young's modulus are equivalent to steel.SOLUTION: A member that constitutes at least one of an inner member, an outer member and a rolling element, constituting a rolling device, is constituted by nickel-based alloy comprising 35-45 wt.% of Cr, 3.7-5 wt.% of Al, balance Ni and unavoidable impurities. Rockwell hardness in a surface layer of the nickel-based alloy constituting at least one of the inner member, the outer member and the rolling element is 40 HRC or less after solid solution treatment, and is 58 HRC or more after precipitation hardening treatment. An average KAM (Kernel Average Misorientation) value in the surface layer of the nickel-based alloy constituting at least one of the inner member, the outer member and the rolling element is 0.35 or less after the solid solution treatment, and is 0.5 or more after the precipitation hardening treatment.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a rolling device and a method for manufacturing the rolling device. [Background technology]

[0002] Known examples of conventionally used mechanical elements include rolling devices such as ball screws, linear guides, linear bearings, ball splines, etc. Such rolling devices include an inner member having a raceway surface on its outer surface, an outer member having a raceway surface facing the raceway surface of the inner member and disposed outside the inner member, and a plurality of rolling elements disposed between the raceway surfaces so as to be able to roll, thereby allowing the outer member to reciprocate or rotate in the axial or circumferential direction of the inner member.

[0003] In this type of rolling device, multiple rolling elements disposed between the inner and outer members repeatedly perform rolling motion, so that the components of the rolling device are subjected to repeated contact stress. For this reason, metal materials with excellent fatigue life and wear resistance are generally used for the materials constituting the inner and outer members and rolling elements.

[0004] Furthermore, since this type of rolling device is sometimes used in applications that require a clean environment, such as clean rooms, semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, food processing equipment, etc., or in special environments, such as medical equipment, the materials that make up the inner member, outer member, and rolling elements may be required to have properties such as high corrosion resistance and non-magnetism. Beryllium copper and austenitic stainless steel are conventional materials that are non-magnetic and highly corrosion resistant, and attempts have been made to apply these non-magnetic and highly corrosion resistant materials to rolling devices. For example, Patent Document 1 below discloses a rolling device (motion guide device) using an austenitic metal and a manufacturing method thereof. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2006 / 112213 Summary of the Invention [Problem to be solved by the invention]

[0006] However, materials such as beryllium copper and austenitic stainless steel have a low maximum hardness of about 40HRC on the Rockwell hardness scale, so when rolling devices are made using these materials, there is an issue that the rated load is lower than that of conventional products.As a countermeasure to this issue, in the conventional technology, a larger model number for the rolling device than the conventional one was selected, and the rated load was increased by increasing the size of the rolling device.

[0007] Although ceramic materials exist as non-magnetic, highly corrosion-resistant, and sufficiently hard materials, they have a problem in that it is difficult to manufacture a high-precision rolling device due to their poor workability. Furthermore, ceramic materials have a disadvantage in that they have a high Young's modulus and low toughness, making it impossible to realize a configuration in which pressure can be applied to the rolling device.

[0008] The present invention has been made in consideration of the various problems existing in the prior art described above, and its object is to obtain a material that has high non-magnetic properties and high corrosion resistance, while also having high hardness that makes it usable as a rolling device, and further has workability and Young's modulus comparable to steel, thereby obtaining a rolling device with high performance. [Means for solving the problem]

[0009] The rolling device according to the present invention is a rolling device comprising an inner member having a raceway surface on its outer surface, an outer member having a raceway surface opposing the raceway surface of the inner member and disposed outside the inner member, and a plurality of rolling elements disposed between the raceway surfaces so as to be able to roll freely, wherein at least one of the inner member, the outer member, and the rolling elements is made of a nickel-based alloy containing 35 to 45% by weight of Cr, 3.7 to 5% by weight of Al, the balance being Ni and unavoidable impurities, and the nickel-based alloy constituting at least one of the inner member, the outer member, and the rolling elements has a Rockwell hardness of 40 HRC or less after solution treatment and 58 HRC or more after precipitation hardening treatment, and the average KAM (Kernel Average Misorientation) value of the nickel-based alloy constituting at least one of the inner member, the outer member, and the rolling elements is 0.35 or less after solution treatment and 0.5 or more after precipitation hardening treatment.

[0010] A method for manufacturing a rolling device according to the present invention is a method for manufacturing a rolling device comprising an inner member having a raceway surface on an outer surface thereof, an outer member having a raceway surface opposing the raceway surface of the inner member and disposed outside the inner member, and a plurality of rolling elements disposed between the raceway surfaces to freely roll, the method comprising the steps of: selecting a nickel-based alloy consisting of 35 to 45 wt. % Cr, 3.7 to 5 wt. % Al, the balance Ni and unavoidable impurities as a material constituting at least one of the inner member, the outer member, and the rolling elements; setting a Rockwell hardness of a surface layer of the nickel-based alloy constituting at least one of the inner member, the outer member, and the rolling elements to 40 HRC or less after a solid solution treatment and 58 HRC or more after a precipitation hardening treatment; and setting a Kernel Average Hardness (KAM) of the surface layer of the nickel-based alloy constituting at least one of the inner member, the outer member, and the rolling elements to 40 HRC or less after a solid solution treatment and 58 HRC or more after a precipitation hardening treatment. The present invention is characterized in that the misorientation value is 0.35 or less after solution treatment and 0.5 or more after precipitation hardening treatment. Effect of the Invention

[0011] According to the present invention, a material is obtained which has high non-magnetic properties and high corrosion resistance, yet has high hardness that allows it to be used as a rolling device, and further has workability and Young's modulus comparable to steel, thereby making it possible to obtain a rolling device with high performance. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a flow chart showing the processing steps of the nickel-based alloy according to the present embodiment. [Diagram 2] FIG. 1 shows a test piece used in a Jominy test, in which (a) shows a top view and (b) shows a front view. [Diagram 3] FIG. 1 is a flow chart for explaining a test method of a Jominy test. [Figure 4] FIG. 1 is a diagram showing the results of temperature measurement over time measured using a test piece in a Jominy test. [Diagram 5] FIG. 1 is a diagram showing hardness values ​​measured using test pieces in a Jominy test after solution treatment and after precipitation hardening treatment, at each distance from the lower end of the test piece. [Figure 6] This is a KAM map showing the measured KAM values ​​visually recognizable by distance from the lower end of the test piece. [Figure 7] FIG. 1 is a diagram showing average KAM (Kernel Average Misorientation) values ​​after solution treatment and after precipitation hardening treatment obtained using test pieces in a Jominy test, for each distance from the lower end of the test piece. [Figure 8] FIG. 13 is a graph showing the results of measuring the relative permeability of the nickel-based alloy according to the present embodiment at different magnetic field strengths using a vibrating sample magnetometer. [Figure 9] FIG. 2 is a flow chart for explaining the test procedure of a hydrogen fluoride corrosion test carried out to verify the corrosion resistance of the nickel-based alloy of the present embodiment. [Figure 10]FIG. 2 is a diagram summarizing test results of the nickel-based alloy according to the present embodiment obtained by a hydrogen fluoride corrosion test. [Figure 11] FIG. 1 is a diagram summarizing test results obtained by a hydrogen fluoride corrosion test on SUS304 as a comparative example. [Figure 12] FIG. 1 is a diagram summarizing test results for HPM75 as a comparative example obtained by a hydrogen fluoride corrosion test. [Figure 13] FIG. 1 is a diagram summarizing test results obtained by a hydrogen fluoride corrosion test for SUS316L as a comparative example. [Figure 14] FIG. 1 is a diagram summarizing test results obtained by a hydrogen fluoride corrosion test on SUS440C as a comparative example. [Figure 15] 1 is an external perspective view illustrating one embodiment of a rolling device according to the present embodiment configured as a linear guide device; [Figure 16] 16 is a cross-sectional view for explaining an endless circulation path provided in the linear guide device shown in FIG. 15. [Figure 17] 1 is a diagram illustrating a case where the rolling device according to the present embodiment is configured as a ball screw device. [Figure 18] 1 is a diagram illustrating a case where the rolling device according to the present embodiment is configured as a spline device. [Figure 19] 1 is a partial vertical sectional perspective view illustrating one embodiment in which the rolling device according to the present embodiment is configured as a rotary bearing device; [Figure 20] FIG. 20 is a vertical sectional view of the rotary bearing device shown in FIG. [Figure 21] 1 is an external perspective view illustrating one embodiment of a rolling device according to the present embodiment configured as a sliding screw device; [Figure 22] FIG. 1 is a diagram for explaining various application examples of the present invention, and is a perspective partial cross-sectional view of the exterior of a rolling device in which a linear motion guide and a ball screw are combined into an integrated structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The inventors, in selecting a material that has high non-magnetic properties and high corrosion resistance, yet has high hardness that can be used as a rolling device, and further has workability and Young's modulus comparable to steel, have focused on nickel-based alloys while examining various materials and conducting test research. This nickel-based alloy is a metallic material belonging to non-ferrous metals, and can be softened by solid solution treatment and then hardened by precipitation hardening treatment. It is also known that the workability and Young's modulus are comparable to steel. Furthermore, nickel itself is a magnetic material, but it becomes non-magnetic by adding chromium. Furthermore, nickel is known to be a highly corrosion-resistant element. Therefore, it was expected that nickel-based alloys would be able to obtain properties such as high non-magnetic properties and high corrosion resistance that are difficult to achieve with steel, which is an iron-based metal. However, mass production is not possible unless the conditions for heat treatment such as solid solution treatment and precipitation hardening treatment are clarified, as well as the manufacturing conditions. After understanding these issues, the inventors conducted various tests and studies to determine the manufacturing conditions that would enable mass production of nickel-based alloys, and succeeded in discovering the nickel-based alloy of the present invention that is applicable to rolling devices, the details of which are described below.

[0014] First, the nickel-based alloy of the present invention, which the inventors found through intensive testing and research, is composed of 35-45 wt% Cr, 3.7-5 wt% Al, the balance being Ni and unavoidable impurities. More specifically, various testing and research were carried out based on the nickel-based alloy according to this embodiment, which satisfies the composition conditions shown in Table 1 below.

[0015] [Table 1]

[0016] As shown in Table 1, the nickel-based alloy according to the present embodiment has the following compositional conditions: 35-45 wt% Cr, 3.7-5 wt% Al, and the balance 55 wt% or more Ni and unavoidable impurities (however, Fe is less than 1 wt%). However, the inventors have confirmed that the nickel-based alloy according to the present embodiment described below has similar properties as long as it is made of 35-45 wt% Cr, 3.7-5 wt% Al, the balance Ni and unavoidable impurities. Therefore, the compositional conditions for determining the non-ferrous metal species applicable to the nickel-based alloy of the present invention may be 35-45 wt% Cr, 3.7-5 wt% Al, the balance Ni and unavoidable impurities.

[0017] Next, the inventors studied the processing steps for applying the nickel-based alloy of this embodiment to a rolling device. As a result, they thought that by adopting the processing steps shown in Fig. 1, it would be possible to manufacture a processed part of a nickel-based alloy applicable to a rolling device. Here, Fig. 1 is a flow chart showing the processing steps of the nickel-based alloy of this embodiment.

[0018] In the processing steps shown in FIG. 1, first, a rolled material made of a nickel-based alloy is prepared (step S10), and the rolled material is subjected to a first heat treatment, a solution treatment, to soften the material (step S11). Then, the material softened by the solution treatment is roughly processed (step S12) to obtain a shape similar to the part shape of the inner member, outer member, or rolling element that constitutes the rolling device. Furthermore, the material that has been roughly processed is subjected to a second heat treatment, a precipitation hardening treatment, to obtain a hardness that can be used as a component of the rolling device (step S13). Then, the material is processed by a grinding process to obtain the part shape of the inner member, outer member, or rolling element that constitutes the rolling device (step S14), and the obtained processed parts are assembled (step S15), and the parts such as the inner member, outer member, or rolling element that constitute the rolling device are completed (step S16). By performing such processing steps, the nickel-based alloy of this embodiment can be applied to the rolling device. However, in order to make the processing steps shown in Fig. 1 executable, if it is possible to grasp the conditions for carrying out the solution treatment which is the first heat treatment shown in step S11, the conditions for carrying out the precipitation hardening treatment which is the second heat treatment shown in step S13, and the depth near the surface of the material after the precipitation hardening treatment which is the second heat treatment shown in step S13 that is useful for a rolling device, then it is possible to know the possible range of the grinding process shown in step S14. Therefore, in order to make the processing steps shown in Fig. 1 executable, the inventors decided to carry out a Jominy test shown in Figs. 2 and 3 to evaluate the characteristics of the heat treatment process.

[0019] Here, Fig. 2 shows a test piece used in the Jominy test, in which (a) shows a top view and (b) shows a front view, and Fig. 3 is a flow chart for explaining the test method of the Jominy test.

[0020] The test piece 10 for the Jominy test conducted by the inventors has a cylindrical body with dimensions of φ25 mm×100 mm, as shown in FIG. 2, and six thermocouple installation holes 11 formed in the longitudinal direction from the top surface to the lower end. A thermocouple is installed in each of the six thermocouple installation holes 11. In the Jominy test of this embodiment, the test piece 10 is heated and then cooling water is applied to the lower end of the test piece 10. At this time, the temperature is measured at a total of six positions, 1.8 mm, 5 mm, 10 mm, 25 mm, 50 mm, and 75 mm from the lower end of the test piece 10, by using the thermocouples installed in each of the six thermocouple installation holes 11. As a result, the temperature at each elapsed time at the six temperature measurement positions set from the lower end of the test piece 10 toward the upper end, and the hardness of the test piece 10 after heat treatment and water cooling are measured, thereby making it possible to evaluate the characteristics of the heat treatment process.

[0021] Next, the method of the Jominy test performed by the inventors will be described with reference to FIG. 3. In the Jominy test of this embodiment, first, the test piece 10 shown in FIG. 2 is prepared (step S30), and the test piece 10 is heated at 1,150° C. for one hour (step S31). When the heating in step S31 is completed, cooling water at 20° C. is applied to the lower end of the test piece 10 to perform a solution treatment on the test piece 10 (step S32). In addition, while continuing to apply the cooling water, the temperature is measured at each elapsed time using six thermocouples installed on the test piece 10 (step S33). Furthermore, after the cooling with the cooling water is completed, the hardness of the test piece 10 for which the solution treatment has been completed is measured (step S34). Thereafter, the test piece 10 is further heated at 585° C. for 16 hours, and then air-cooled to perform a precipitation hardening treatment (step S35). After the precipitation hardening treatment in step S35 is completed, the hardness of the test piece 10 after precipitation hardening is measured (step S36). By carrying out the above steps, the Jominy test is completed.

[0022] The Jominy test shown in Figures 2 and 3 is originally a test method for evaluating the hardenability of steel, and this method is not generally applied to non-ferrous metal materials. However, the inventors have succeeded in evaluating the heat treatment characteristics of the nickel-based alloy of this embodiment, which is a non-ferrous metal material, by using the Jominy test for the first time. Next, the heat treatment characteristics of the nickel-based alloy of this embodiment obtained by using the Jominy test will be described.

[0023] First, FIG. 4 is a diagram showing the measurement results of temperature at each elapsed time measured using a test piece of a Jominy test. The results shown in FIG. 4 are graphs showing the measurement results performed in step S33 in FIG. 3. From the results shown in FIG. 4, it was confirmed that the closer to the lower end of the test piece 10 cooled by cooling water, the faster the cooling rate, and the further away the position, the longer it takes to cool. In other words, when the nickel-based alloy of this embodiment is subjected to a solid solution treatment, it is clear that the closer to the surface layer of the nickel-based alloy to be treated with the solid solution treatment (i.e., shallower), the faster the cooling rate is, and the further away from the surface layer (i.e., deeper), the slower the cooling rate is. From this result, it is clear that the effect of the solid solution treatment to soften the material is higher near the surface layer of the nickel-based alloy (i.e., shallower), so the hardness decreases, and the further away from the surface layer of the nickel-based alloy (i.e., deeper), the lower the effect, so the hardness tends to be maintained.

[0024] Based on the results shown in Fig. 4, the measured hardness values ​​after solution treatment and precipitation hardening treatment in the Jominy test were compared. Here, Fig. 5 is a diagram showing the measured hardness values ​​after solution treatment and precipitation hardening treatment measured using test pieces in the Jominy test, at each distance from the lower end of the test piece.

[0025] As can be seen from FIG. 5, in the conventional knowledge of the technical field, it was believed that only precipitation hardening treatment contributes to an increase in hardness. However, from FIG. 5, which summarizes the results of the Jominy test conducted by the inventors, it became clear that the hardness after precipitation hardening treatment depends on the hardness after solution treatment. Specifically, it became clear that in order to satisfy the condition that the hardness after precipitation hardening treatment is 58HRC or more in Rockwell hardness, which the inventors considered as the hardness condition necessary for use as a component of a rolling device, the hardness at the time point after solution treatment needs to be 40HRC or less in Rockwell hardness. In this way, the knowledge that the hardness after the precipitation hardening treatment, which is the second heat treatment, will not be 58HRC or more unless the hardness is reduced to 40HRC or less in the stage of the solution treatment, which is the first heat treatment, was first revealed by adopting a completely new test evaluation method of applying the Jominy test to nickel-based alloys, which are non-ferrous metals.

[0026] Furthermore, as can be seen from FIG. 5, it has become clear that the condition for the hardness after precipitation hardening treatment to be 58HRC or more when water-cooled is satisfied if the nickel-based alloy is at a depth of 35 mm from the surface. This fact is an important finding in the grinding process shown in step S14 of the processing process of the nickel-based alloy of this embodiment shown in FIG. 1. This finding shows that when cutting out components of a rolling device from a rolled material that is subjected to rough processing and grinding, for example, if the raceway surface that needs to have a hardness of 58HRC or more is located at a depth of 35 mm or more, the hardness of 58HRC or more cannot be obtained after precipitation hardening treatment. In that case, the material should be cut out in advance so that the raceway surface is within 35 mm from the material surface, and then the solid solution treatment should be performed. In other words, the heat treatment characteristics of the nickel-based alloy of this embodiment have been clarified by the finding obtained this time, so that the nickel-based alloy can be used as a component of a rolling device and mass-produced.

[0027] Based on the findings in FIG. 5, the inventors conducted further studies. That is, the inventors performed analysis and evaluation based on a new evaluation method called KAM (Kernel Average Misorientation) value by performing measurements and analysis using EBSD (Electron Backscatter Diffraction), which is an additional function of SEM (Scanning Electron Microscope). This KAM value is an index adopted to specify the cooling rate after solution treatment. Specifically, the KAM value is a value that can be calculated by EBSD measurement using SEM, and indicates the crystal orientation difference. The EBSD measurement was performed under analysis conditions of an acceleration voltage of 15 kV, a step size of 0.1 μm, and an MMA threshold value of 5. The sample was cut out, mechanically polished and chemically polished to a mirror surface, and ion milling was performed at an acceleration voltage of 40 kV for 10 minutes to produce it. Fig. 6 shows a KAM map that visually indicates the KAM values ​​measured in this way, for each distance from the lower end of the test piece 10. Here, Fig. 6 shows a KAM map that visually indicates the measured KAM values, for each distance from the lower end of the test piece. In Fig. 6, the darker the hatching in the KAM map, the higher the calculated crystal orientation difference (which is an index of the amount of dislocation) and the higher the hardness value.

[0028] Furthermore, the inventors quantified the KAM map shown in FIG. 6 and created the diagram shown in FIG. 7. Here, FIG. 7 is a diagram showing the average KAM (Kernel Average Misorientation) values ​​after solution treatment and after precipitation hardening treatment obtained using a test piece of a Jominy test, for each distance from the lower end of the test piece. As can be seen from FIG. 7, at a depth of 35 mm from the surface of the nickel-based alloy, which is a condition under which the hardness after precipitation hardening treatment is 58HRC or more, the average KAM value after solution treatment is 0.35 or less, and the average KAM value after precipitation hardening treatment is 0.5 or more. That is, as a new index for applying the nickel-based alloy according to this embodiment as a component of a rolling device and mass-producing it, the condition that the average KAM value is 0.35 or less after solution treatment and 0.5 or more after precipitation hardening treatment was clarified. By being able to find a new index for applying the nickel-based alloy as a component of a rolling device, the applicability of the nickel-based alloy according to this embodiment can be expanded.

[0029] The inventors' test and research described above has revealed that the nickel-based alloy according to this embodiment has a high hardness that can be used for rolling devices by subjecting it to a predetermined heat treatment, and can also be used as a material with workability and Young's modulus comparable to that of steel. Therefore, the inventors next verified whether the nickel-based alloy according to this embodiment has high non-magnetic properties.

[0030] The inventors prepared a nickel-based alloy according to the present embodiment, in which the Rockwell hardness in the surface layer (up to a depth of 35 mm from the surface) is 40 HRC or less after solution treatment and 58 HRC or more after precipitation hardening treatment, and the average KAM (Kernel Average Misorientation) value in the surface layer (up to a depth of 35 mm from the surface) is 0.35 or less after solution treatment and 0.5 or more after precipitation hardening treatment, and evaluated the nonmagnetic properties by measuring the relative permeability of this nickel-based alloy.

[0031] First, the inventors measured the relative permeability using a measuring device called a Ferromast permeability meter, which is generally used to measure the relative permeability of low-permeability materials. The measurement conditions are shown in Table 2.

[0032] [Table 2]

[0033] The results of the measurements using the Ferromaster permeameter shown in Table 2 are shown in Table 3. Note that, in addition to the nickel-based alloy according to the present embodiment, the measurements using the Ferromaster permeameter were also performed for comparison with SUS304 that had been subjected to solid solution treatment as Comparative Example 1, HPM75 as Comparative Example 2, and SUS304 after work hardening as Comparative Example 3.

[0034] [Table 3]

[0035] As shown in Table 3, the relative permeability of the nickel-based alloy according to this embodiment is 1.001μ as a result of measurement using a Ferromast permeability meter. r In other words, the nickel-based alloy according to this embodiment has a magnetic field strength of 3.5×10 4 Relative permeability μ in A / m r But μ r It was also found that the nickel-based alloy according to this embodiment is a material having higher non-magnetic properties than the other comparative examples 1 to 3.

[0036] However, in the measurements using the Ferromaster permeability meter shown in Tables 2 and 3, the lower limit of measurable relative permeability is 1.001μ r Therefore, more detailed values ​​cannot be obtained. Therefore, the inventors decided to measure the magnetic properties of the nickel-based alloy according to this embodiment in detail using a vibrating sample magnetometer (VSM). Table 4 shows the measurement conditions of the vibrating sample magnetometer.

[0037] [Table 4]

[0038] The results of the measurements using the vibrating sample magnetometer shown in Table 4 are shown in Table 5. Note that, for comparison, measurements using the vibrating sample magnetometer were also performed on solution-treated SUS304 as Comparative Example 1, HPM75 as Comparative Example 2, and SUS304 after work hardening as Comparative Example 3, in addition to the nickel-based alloy according to the present embodiment.

[0039] [Table 5]

[0040] FIG. 8 is a graph showing the measurement results using a vibrating sample magnetometer. FIG. 8 is a graph showing the measurement results of the relative permeability of the nickel-based alloy according to this embodiment for each magnetic field strength using a vibrating sample magnetometer. As shown in FIG. 8 and Table 5, the measurement using the vibrating sample magnetometer showed that the nickel-based alloy according to this embodiment has a maximum relative permeability of 1.00035μ, which is lower than the lower limit of the measurement using a Ferromast permeability meter. r It was revealed that the nickel-based alloy according to the present embodiment exhibited a very low value of -7.8×10. This result indicates that the nickel-based alloy according to the present embodiment has very high non-magnetic properties, even compared to the materials of Comparative Examples 1 to 3. In addition, when the nickel-based alloy was measured using a vibrating sample magnetometer, the applied magnetic field was -7.8×10 5 ~7.8×10 5 It was revealed that the nickel-based alloy according to the present embodiment exhibits a very low relative magnetic permeability in a wide range of magnetic fields, from 3.5×10 A / m. 4 Relative permeability μ in A / m r But μ r ≦1.0004, and this inequality satisfies the applied magnetic field of -7.8×10 5 ~7.8×10 5 It was also found that this holds true in the range of A / m.

[0041] The inventors' research and testing described above has revealed that the nickel-based alloy according to this embodiment has high hardness that can be used as a rolling device by subjecting it to a predetermined heat treatment, and can be used as a material with workability and Young's modulus comparable to that of steel. It has also been revealed that the nickel-based alloy according to this embodiment has high non-magnetic properties. Therefore, the inventors next verified whether the nickel-based alloy according to this embodiment has high corrosion resistance.

[0042] The details of the test conducted by the inventors to verify the corrosion resistance of the nickel-based alloy according to this embodiment will be described with reference to Fig. 9. Here, Fig. 9 is a flow chart for explaining the test procedure of the hydrogen fluoride corrosion test conducted to verify the corrosion resistance of the nickel-based alloy according to this embodiment.

[0043] The hydrogen fluoride corrosion test conducted by the inventors was conducted to evaluate the corrosion resistance of the test material against hydrofluoric acid (HF), and the test material was five types of materials, namely, the nickel-based alloy according to the present embodiment, SUS304, HPM75, SUS316L, and SUS440C. Two test pieces of the test material were prepared for each material, and two types of solutions were prepared by diluting hydrofluoric acid with ultrapure water, with solution concentrations of 0.1% and 1%. As a specific procedure for the hydrogen fluoride corrosion test, as shown in FIG. 9, first, the test piece surface is ground to a uniform roughness Ra of 0.1 to 0.2 μm (step S90), and then the test piece surface is washed with n-hexane (step S91). The test pieces thus prepared were masked with a masking seal with a hole of φ30 mm (step S92), and solutions with a solution concentration of 0.1% and 1% were dropped onto each sample to bring them into contact with the liquid, and then air-dried for 24 hours (step S93). Note that, in the air-drying performed in step S93, even if the solution dried, no additional solution was added and the test pieces were allowed to air-dry as they were. Thereafter, the test pieces were washed with running ultrapure water, and then air-dried for another 24 hours (step S94). Finally, the test piece surface obtained through the process consisting of steps S90 to S94 was photographed with a digital camera and a digital microscope (step S95), and the photographed photographs were visually observed to evaluate the corrosion resistance of the test material.

[0044] The test results obtained by the hydrogen fluoride corrosion test described with reference to FIG. 9 are shown in FIG. 10 to FIG. 14. Here, FIG. 10 is a diagram summarizing the test results of the nickel-based alloy according to the present embodiment obtained by the hydrogen fluoride corrosion test, FIG. 11 is a diagram summarizing the test results of SUS304 as a comparative example obtained by the hydrogen fluoride corrosion test, FIG. 12 is a diagram summarizing the test results of HPM75 as a comparative example obtained by the hydrogen fluoride corrosion test, FIG. 13 is a diagram summarizing the test results of SUS316L as a comparative example obtained by the hydrogen fluoride corrosion test, and FIG. 14 is a diagram summarizing the test results of SUS440C as a comparative example obtained by the hydrogen fluoride corrosion test. In addition, in FIG. 10 to FIG. 14, for two types of hydrogen fluoride solution concentrations of 0.1% and 1%, the upper row shows an overall appearance photograph, the middle row shows an enlarged photograph at a magnification of 20 times, and the lower row shows an enlarged photograph at a magnification of 100 times.

[0045] As is clear from Figs. 10 to 14, the nickel-based alloy according to this embodiment was confirmed to maintain an extremely clean state without rust or deterioration of surface properties, even though it was exposed to hydrogen fluoride solutions with a solution concentration of 0.1% and a solution concentration of 1% and then air-dried. On the other hand, among the materials used as comparative examples, for HPM75 shown in Fig. 12 and SUS440C shown in Fig. 14, rust was confirmed to have occurred on the entire surface of the test piece. In addition, for SUS304 shown in Fig. 10 and SUS316L shown in Fig. 13, although there was little rust, deterioration of surface properties was confirmed. It was confirmed by the hydrogen fluoride corrosion test described above that the nickel-based alloy according to this embodiment has extremely high corrosion resistance.

[0046] As described above, the inventors' test and research have revealed that the nickel-based alloy according to this embodiment has the following characteristics, and while it has high non-magnetic properties and high corrosion resistance, it also has high hardness that allows it to be used as a rolling device, and furthermore, it is a material with workability and Young's modulus comparable to that of steel. The alloying components of the nickel-based alloy according to the present invention are 35-45% by weight of Cr, 3.7-5% by weight of Al, the balance being Ni and unavoidable impurities. The Rockwell hardness of the surface layer of the nickel-based alloy is 40HRC or less after solution treatment, and 58HRC or more after precipitation hardening treatment. The average KAM (Kernel Average Misorientation) value in the surface layer of the nickel-based alloy is 0.35 or less after solution treatment and 0.5 or more after precipitation hardening treatment. The surface layer of the nickel-based alloy includes at least a portion extending from the surface of the nickel-based alloy to a depth of 35 mm. - Magnetic field strength of nickel-based alloys: 3.5×10 4 Relative permeability μ in A / m r is μ r <1.001 inequality. Furthermore, the magnetic field strength of nickel-based alloys is 3.5×10 4 Relative permeability μ in A / m r is μ r It satisfies the inequality ≦1.0004. By applying the nickel-based alloy according to the present invention having the above-mentioned configuration to a rolling device, a rolling device having high performance can be obtained. Next, an example in which a member made of the nickel-based alloy according to the present invention is applied to a rolling device will be described.

[0047] [Application example to rolling devices] A specific embodiment of a rolling device using a member made of the nickel-based alloy according to the present invention as a rolling and sliding member will be described with reference to the drawings. The embodiments of the rolling device exemplified below do not limit the invention according to each claim, and not all combinations of features described in the embodiments are necessarily essential to the solution of the invention. In addition, the "rolling device" in this specification includes any device that involves rolling and sliding motion, such as rolling bearings used in machine tools, non-lubricated bearings used in vacuum, linear guides and linear guide devices, ball spline devices, ball screw devices, roller screw devices, cross roller rings, etc.

[0048] (Example of application to linear guide devices) The rolling device according to the present embodiment can be configured as a linear guide device as shown in Fig. 15 and Fig. 16. By using the components made of the nickel-based alloy according to the present invention as the components of the linear guide device, a rolling device with high performance can be realized, which includes components having high non-magnetic properties and high corrosion resistance, high hardness usable as a rolling device, workability, and Young's modulus comparable to steel. Here, Fig. 15 is an external perspective view illustrating one embodiment of the rolling device according to the present embodiment configured as a linear guide device. Also, Fig. 16 is a cross-sectional view for explaining the infinite circulation path provided in the linear guide device shown in Fig. 15.

[0049] First, the configuration of the linear guide device 40 illustrated in Figures 15 and 16 will be described. The linear guide device 40 as a rolling device according to this embodiment includes a track rail 41 as an inner member, and a moving block 43 as an outer member slidably attached via balls 42 installed on the track rail 41 as a plurality of rolling elements. The track rail 41 is a long member having a cross section perpendicular to its longitudinal direction formed into a substantially rectangular shape, and on its surface (top and both side surfaces), a rolling element rolling surface 41a is formed over the entire length of the track rail 41 as a track surface that becomes a track along which the balls 42 roll.

[0050] Here, the track rail 41 may be formed to extend linearly or curvedly. In addition, the number of rolling element rolling surfaces 41a illustrated in Fig. 15 and Fig. 16 is four in total, two on each side, but the number can be changed as desired depending on the application of the linear guide device 40.

[0051] On the other hand, the moving block 43 is provided with a loaded rolling element rolling surface 43a as a raceway surface at a position corresponding to each of the rolling element rolling surfaces 41a. The rolling element rolling surface 41a of the track rail 41 and the loaded rolling element rolling surface 43a of the moving block 43 form a loaded rolling path 52, in which a plurality of balls 42 are sandwiched. Furthermore, the moving block 43 is provided with four unloaded rolling paths 53 extending parallel to each of the rolling element rolling surfaces 41a, and a direction change path 55 connecting each of the unloaded rolling paths 53 and each of the loaded rolling paths 52. A combination of one loaded rolling path 52 and one unloaded rolling path 53 and a pair of direction change paths 55 connecting them forms one infinite circulation path (see FIG. 16).

[0052] Furthermore, a plurality of balls 42 are installed so as to be able to circulate infinitely in an infinite circulation path consisting of a loaded rolling path 52, an unloaded rolling path 53, and a pair of direction change paths 55, 55, thereby enabling the moving block 43 to move back and forth relative to the track rail 41.

[0053] In the linear guide device 40 according to this embodiment having the above-mentioned configuration, it is preferable to use the nickel-based alloy according to the present invention described above for at least one of the track rail 41 as the inner member, the moving block 43 as the outer member, and the balls 42 installed as the multiple rolling elements.

[0054] In the linear guide device 40 according to this embodiment, the nickel-based alloy of the present invention may be used for all of the components, or may be used for some of the components. This selection may be made depending on the usage environment and usage purpose of the linear guide device 40, manufacturing costs, etc.

[0055] (Example of application to rolling element screw devices) Moreover, the rolling device according to this embodiment can be configured as a ball screw device 56 as shown in Fig. 17. Fig. 17 is a diagram illustrating the rolling device according to this embodiment configured as a ball screw device. Such a ball screw device 56 is a device including a screw shaft 57 as an inner member, and a nut member 59 as an outer member attached to the screw shaft 57 via a plurality of balls 58 so as to be relatively rotatable.

[0056] The screw shaft 57 is an inner member having a rolling element rolling groove 57a formed as a spiral raceway surface on its outer circumferential surface, while the nut member 59 is an outer member having a load rolling groove formed as a spiral raceway surface corresponding to the rolling element rolling groove 57a on its inner circumferential surface. The nut member 59 is capable of reciprocating relative to the screw shaft 57 in accordance with the relative rotational movement of the screw shaft 57 with respect to the nut member 59.

[0057] Furthermore, by using the nickel-based alloy according to the present invention described above for the screw shaft 57, nut member 59, balls 58, and other members that make up the ball screw device 56, it is possible to realize a high-performance ball screw device 56 whose constituent members include materials that have high non-magnetic properties and high corrosion resistance, high hardness that makes them suitable for use as a rolling device, and workability and a Young's modulus that are comparable to steel.

[0058] (Example of application to spline devices) Furthermore, the rolling device according to this embodiment can be configured as, for example, a spline device 60 as shown in Fig. 18. Fig. 18 is a diagram illustrating the rolling device according to this embodiment configured as a spline device.

[0059] Here, the configuration of the spline device 60 shown in FIG. 18 will be briefly described. The spline device 60 has a spline shaft 61 as an inner member, and a cylindrical outer cylinder 63 as an outer member movably attached to the spline shaft 61 via balls 62 as a plurality of rolling elements. On the surface of the spline shaft 61, a rolling element rolling surface 61a is formed as a raceway surface that becomes the raceway of the balls 62 and extends in the axial direction of the spline shaft 61. On the outer cylinder 63 attached to the spline shaft 61, a loaded rolling element rolling surface is formed as a raceway surface corresponding to the rolling element rolling surface 61a. On these loaded rolling element rolling surfaces, a plurality of protrusions are formed that extend in the direction in which the rolling element rolling surface 61a extends. A loaded rolling path is formed between the loaded rolling element rolling surface formed on the outer cylinder 63 and the rolling element rolling surface 61a formed on the spline shaft 61. Next to the loaded rolling path, an unloaded return path is formed along which the balls 62 that are released from the load move. A cage 64 that aligns and holds a number of balls 62 in a circuit shape is incorporated in the outer cylinder 63. The balls 62 are freely rollable between the loaded rolling element rolling surface of the outer cylinder 63 and the rolling element rolling surface 61a of the spline shaft 61, and are arranged so as to circulate infinitely through an unloaded return passage, thereby allowing the outer cylinder 63 to reciprocate relatively to the spline shaft 61.

[0060] Also in the case of the spline device 60 shown in FIG. 18, by using the nickel-based alloy according to the present invention described above for the spline shaft 61, outer cylinder 63, balls 62 and other members constituting the spline device 60, it is possible to realize a high-performance spline device 60, whose constituent members include materials with high nonmagnetic properties and high corrosion resistance, high hardness that allows use as a rolling device, and workability and Young's modulus comparable to steel.

[0061] (Example of application to a rotating bearing device) Furthermore, the rolling device according to this embodiment can be configured as a rotary bearing device 70 as shown in Fig. 19 and Fig. 20. Fig. 19 is a partial vertical cross-sectional perspective view illustrating one embodiment in which the rolling device according to this embodiment is configured as a rotary bearing device. Fig. 20 is a vertical cross-sectional view of the rotary bearing device shown in Fig. 19.

[0062] As shown in Figures 19 and 20, a rolling device configured as a rotary bearing device 70 has an inner ring 71 as an inner member having an inner raceway surface 72 with a V-shaped cross section on its outer peripheral surface, an outer ring 73 as an outer member having an outer raceway surface 74 with a V-shaped cross section on its inner peripheral surface, and rollers 77 as a plurality of rolling elements cross-arranged so as to be able to roll between a raceway 75 formed by the inner raceway surface 72 and the outer raceway surface 74 and having a substantially rectangular cross section, so that the inner ring 71 and the outer ring 73 perform relative rotational movement in the circumferential direction.

[0063] By using the nickel-base alloy according to the present invention described above for the components constituting such a rotating bearing device 70, it is possible to realize a rotating bearing device 70 having high performance, including components made of materials that have high non-magnetic properties and high corrosion resistance, high hardness sufficient for use as a rolling device, and workability and a Young's modulus comparable to steel.

[0064] (Example of application to a sliding screw device) The above-mentioned devices have been described by taking as examples devices in which a plurality of rolling elements are interposed between an inner member and an outer member. However, the scope of application of the present invention, which is characterized by configuring a high-performance rolling device including components made of the nickel-based alloy according to the present invention, which have high non-magnetic properties and high corrosion resistance, high hardness usable as a rolling device, workability, and a material with a Young's modulus comparable to steel, is not limited to those using such rolling elements, and can also be suitably used for devices in which the inner member and the outer member are in direct contact with each other without the intermediation of rolling elements, allowing relative motion.

[0065] For example, as shown in FIG. 21, the present invention can be applied to a rolling device configured as a sliding screw device 80. Here, FIG. 21 is an external perspective view illustrating one embodiment of the rolling device according to the present embodiment configured as a sliding screw device. The sliding screw device 80 shown in FIG. 21 has a screw shaft 81 as an inner member having a screw groove formed as a helical raceway surface on its outer circumferential surface, and a nut member 83 as an outer member having a nut groove formed as a helical raceway surface corresponding to the screw groove on its inner circumferential surface, so that the nut member 83 can reciprocate relative to the screw shaft 81 in accordance with the relative rotational movement of the screw shaft 81 with respect to the nut member 83.

[0066] 21, the nickel-based alloy according to the present invention can be used for either or both of the constituent members, the screw shaft 81 and the nut member 83. By using the nickel-based alloy according to the present invention for the members constituting such a sliding screw device 80, it is possible to realize a sliding screw device 80 having high performance, including constituent members made of a material with high nonmagnetic properties and high corrosion resistance, high hardness usable as a rolling device, workability, and Young's modulus comparable to steel.

[0067] Although the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above embodiments. Various modifications and improvements can be made to the above embodiments.

[0068] For example, the present invention can be applied to a rolling device 90 in which a linear motion guide and a ball screw are combined into an integrated structure as shown in Fig. 22. In the case of the rolling device 90 shown in Fig. 22, the screw shaft 91 and the moving block 93 are installed via a plurality of balls 95, but it is also possible for the screw shaft 91 and the moving block 93 to be configured as a sliding screw without the plurality of balls 95.

[0069] It will be apparent from the description of the claims that such modified or improved forms may also be included within the technical scope of the present invention. [Explanation of symbols]

[0070] 10 test piece, 11 thermocouple installation hole, 40 linear guide device (rolling device), 41 raceway rail (inner member), 41a rolling body rolling surface (raceway surface), 42 ball (rolling body), 43 moving block (outer member), 43a loaded rolling body rolling surface (raceway surface), 48, 49 screw hole, 52 loaded rolling path, 53 unloaded rolling path, 55 direction change path, 56 ball screw device (rolling device), 57 screw shaft (inner member), 57a rolling body rolling groove (raceway surface), 58 ball (rolling body), 59 nut member (outer member), 60 spline device (rolling device), 61 spline shaft (inner member), 61a rolling body rolling surface (raceway surface), 62 ball (rolling body), 63 outer cylinder (outer member), 64 Cage, 70 rolling bearing device (rolling device), 71 inner ring (inner member), 72 inner raceway surface (raceway surface), 73 outer ring (outer member), 74 outer raceway surface (raceway surface), 75 raceway, 77 roller (rolling element), 80 sliding screw device, 81 screw shaft (inner member), 83 nut member (outer member), 90 rolling device, 91 screw shaft (inner member), 93 moving block (outer member), 95 ball (rolling element).

Claims

1. an inner member having a raceway surface on an outer surface thereof; an outer member having a raceway surface facing the raceway surface of the inner member and disposed outside the inner member; A plurality of rolling elements rollably disposed between the raceway surfaces; In a rolling device comprising: At least one of the inner member, the outer member, and the rolling elements is made of a nickel-based alloy containing 35 to 45% by weight of Cr, 3.7 to 5% by weight of Al, the balance being Ni and unavoidable impurities; the surface layer of the nickel-based alloy constituting at least one of the inner member, the outer member, and the rolling elements has a Rockwell hardness of 40 HRC or less after a solution treatment and 58 HRC or more after a precipitation hardening treatment; a surface layer of the nickel-based alloy constituting at least one of the inner member, the outer member, and the rolling elements has an average KAM (Kernel Average Misorientation) value of 0.35 or less after a solution treatment and 0.5 or more after a precipitation hardening treatment.

2. The rolling device according to claim 1, The magnetic field strength of the nickel-based alloy constituting at least one of the inner member, the outer member, and the rolling elements is 3.5×10 ４ Relative permeability μ in A / m ｒ But μ ｒ <1.

001.

3. The rolling device according to claim 1, The magnetic field strength of the nickel-based alloy constituting at least one of the inner member, the outer member, and the rolling elements is 3.5×10 ４ Relative permeability μ in A / m ｒ But μ ｒ A rolling device, characterized in that it satisfies the inequality: ≦1.0004.

4. an inner member having a raceway surface on an outer surface thereof; an outer member having a raceway surface facing the raceway surface of the inner member and disposed outside the inner member; A plurality of rolling elements rollably disposed between the raceway surfaces; A method for manufacturing a rolling device comprising: a nickel-based alloy containing 35 to 45 wt. % Cr, 3.7 to 5 wt. % Al, the balance being Ni and unavoidable impurities, is selected as a material constituting at least one of the inner member, the outer member, and the rolling elements; The surface layer of the nickel-based alloy constituting at least one of the inner member, the outer member and the rolling elements has a Rockwell hardness of 40 HRC or less after a solution treatment and 58 HRC or more after a precipitation hardening treatment; and A manufacturing method for a rolling device, characterized in that an average KAM (Kernel Average Misorientation) value in a surface layer of the nickel-based alloy constituting at least one of the inner member, the outer member, and the rolling elements is set to 0.35 or less after a solid solution treatment, and to 0.5 or more after a precipitation hardening treatment.

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