JP2019059983A - Bearing component and ball bearing - Google Patents

Abstract

To provide a bearing component having both dimensional stability and static load capacity.SOLUTION: The steel bearing component according to one embodiment of the present invention has a hardened layer on its surface. The hardened layer includes a martensite phase, an austenite phase, and a carbide phase. The relationships of 0.064×Y+0.002×Z<1 and 0.43×X-0.15×Y>1 are satisfied where X (unit: °) is the half width in the X-ray diffraction of the martensite phase, Y (unit: percent) is the volume ratio of the austenite phase in the hardened layer, and Z (unit: percent) is the area ratio of the carbide phase in the hardened layer.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a bearing component and a rolling bearing.

  A hardened hardened layer is provided on the raceway surfaces of the inner and outer rings constituting the rolling bearing and on the rolling surface of the rolling element constituting the rolling bearing. The quench hardened layer contains a retained austenite phase. When the rolling bearing is used for a long time in a high temperature environment, the retained austenite phase decomposes into a ferrite phase and a carbide phase. Because the retained austenite phase and the ferrite phase have different crystal structures, a volume change (expansion) occurs when the retained austenite phase is decomposed. For example, when the volume of the inner ring constituting the rolling bearing changes (expansion), the fitting margin with the shaft decreases to cause creep. Thus, the volume change (expansion) of the bearing component that constitutes the rolling bearing causes the early damage of the rolling bearing.

  When a large load is applied while the rolling bearing is stationary, indentations may occur on the raceway surface and the rolling surface. Such an indentation causes a decrease in the rotational accuracy of the rolling bearing and an abnormal noise at the time of rotation. As described above, high dimensional stability and high static load capacity are required for the bearing components that constitute the rolling bearing.

  For example, Japanese Patent Application Laid-Open No. 2013-124416 (Patent Document 1) describes a technique for improving dimensional stability by carbonitriding the surface of a bearing component.

JP, 2013-124416, A

  The mechanical properties of the bearing parts that make up the rolling bearing are related to the metallographic structure of the steel that makes up the bearing parts. However, it has not been clarified what kind of metallographic structure the steel constituting the bearing component improves dimensional stability and static load capacity.

  The present invention has been made in view of the problems of the prior art as described above. More specifically, the present invention provides a bearing component and a rolling bearing capable of achieving both dimensional stability and static load capacity.

  The steel bearing component according to one aspect of the present invention has a quench hardened layer on the surface. The quenched and hardened layer contains a martensite phase, an austenite phase, and a carbide phase. Half-width in X-ray diffraction of martensite phase is X (unit: °), volume ratio of austenite phase in quenched hardened layer is Y (unit: percent), area ratio of carbide phase in quenched hardened layer is Z If (unit: percentage), the relationship of 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1 is satisfied.

  The hardness (static load capacity) of the quench-hardened layer increases as the amount of carbon in the martensitic phase increases (as the half-width width in X-ray diffraction of the martensitic phase increases). On the other hand, as the amount of carbon in the martensitic phase increases, the volume ratio of the austenite phase in the quenched and hardened layer increases, and the carbide area ratio in the quenched and hardened layer decreases. That is, as the amount of carbon in the martensitic phase increases, the dimensional stability decreases. From another point of view, the static load capacity and dimensional stability of the quench-hardened layer are in a trade-off relationship. According to the findings found by the present inventors, when the quench-hardened layer satisfies the relationship of 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1, Static load capacity can be improved as long as dimensional stability can be maintained. Therefore, according to the bearing component according to one aspect of the present invention, dimensional stability and static load capacity can be compatible.

  In the above bearing component, the half width may be the half width of the diffraction peak in the {211} plane of the martensitic phase by the CuKα ray. In the above bearing component, the steel may be SUJ2 defined in JIS.

In the above bearing component, the dimensional change rate of the quench hardened layer may be 6 × 10 ⁻⁴ or less. The indentation depth may be 0.2 μm or less when a ceramic ball having a diameter of 3/8 inch is pressed to the quenched and hardened layer with a load of 471N.

  A rolling bearing according to an aspect of the present invention is a steel having a first raceway surface and having a second raceway surface, wherein the second raceway surface is disposed to face the first raceway surface. And an outer race, and a steel rolling element disposed between the inner race and the outer race and having a rolling surface. A quench hardened layer is provided on at least one of the first raceway surface, the second raceway surface, and the rolling surface. The quenched and hardened layer contains a martensite phase, an austenite phase, and a carbide phase. Half-width in X-ray diffraction of martensite phase is X (unit: °), volume ratio of austenite phase in quenched hardened layer is Y (unit: percent), area ratio of carbide phase in quenched hardened layer is Z When (unit: percent), 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1 are satisfied.

  According to the bearing component and the rolling bearing according to one aspect of the present invention, dimensional stability and static load capacity can be compatible.

It is a top view of bearing component 10 concerning an embodiment. It is sectional drawing in II-II of FIG. It is an enlarged view in III of FIG. It is a sectional view of rolling bearing 100 concerning an embodiment. It is a process chart showing a manufacturing method of bearing part 10 concerning an embodiment.

  The details of the embodiment will be described with reference to the drawings. In the following drawings, the same or corresponding parts will be denoted by the same reference numerals, and the description thereof will not be repeated.

(Configuration of bearing component according to the embodiment)
Hereinafter, the configuration of the bearing component 10 according to the embodiment will be described.

  The bearing component 10 according to the embodiment is, for example, an inner ring of a rolling bearing. However, the bearing component 10 according to the embodiment is not limited to this. The bearing component 10 according to the embodiment may be an outer ring or a rolling element of a rolling bearing. In the following, the case where the bearing component 10 according to the embodiment is an inner ring of a radial ball bearing will be described as an example.

  The bearing component 10 according to the embodiment is made of steel. The steel which comprises the bearing component 10 which concerns on embodiment is bearing steel, for example. The steel constituting the bearing component 10 according to the embodiment is preferably a high carbon chromium bearing steel defined in JIS G 4805: 2008 (hereinafter simply referred to as “JIS standard”). More specifically, the steel constituting the bearing component 10 according to the embodiment is SUJ 2 defined in the JIS standard.

  FIG. 1 is a top view of a bearing component 10 according to an embodiment. FIG. 2 is a cross-sectional view taken along line II-II of FIG. As shown in FIGS. 1 and 2, the bearing component 10 according to the embodiment has an annular shape (ring shape).

  The bearing component 10 according to the embodiment has a central axis A. The bearing component 10 according to the embodiment has an upper surface 10a, a bottom surface 10b, an inner peripheral surface 10c, and an outer peripheral surface 10d. The top surface 10 a and the bottom surface 10 b are orthogonal to the central axis A. The bottom surface 10 b is the opposite surface of the top surface 10 a. The inner circumferential surface 10c and the outer circumferential surface 10d are continuous with the top surface 10a and the bottom surface 10b. The inner circumferential surface 10 c and the outer circumferential surface 10 d are parallel to the central axis A. The distance between the inner circumferential surface 10 c and the central axis A is smaller than the distance between the outer circumferential surface 10 d and the central axis A. The outer circumferential surface 10d constitutes a raceway surface. A raceway groove is provided on the outer circumferential surface 10d. The outer circumferential surface 10 d is recessed toward the inner circumferential surface 10 c in the raceway groove.

  FIG. 3 is an enlarged view of III in FIG. As shown in FIG. 3, the bearing component 10 according to the embodiment has a quenched and hardened layer 11. The quench-hardened layer 11 is a layer composed of steel hardened by quenching. The quench hardened layer 11 is on the surface of the bearing component 10 according to the embodiment. More specifically, the quench hardened layer 11 is on the outer peripheral surface 10 d.

Quenched and hardened layer 11 contains an austenite phase, a martensite phase, and a carbide phase. The quench hardened layer 11 also contains a ferrite phase. The austenite phase is a high temperature phase of iron (Fe) having a face center cubic (fcc) structure. The martensitic phase is a non-equilibrium phase of iron obtained by quenching an austenitic phase containing carbon (solid solution of carbon). The carbide phase is a phase composed of iron carbides (eg, Fe ₃ C, cementite). The ferrite phase is a low temperature phase of iron having a bcc (body center cubic) structure.

  The half width of the martensite phase in the quenched and hardened layer 11 is X (unit: °), the volume ratio of the austenite phase in the quenched and hardened layer 11 is Y (unit: percent), and the carbide phase in the quenched and hardened layer 11 Assuming that the area ratio of (Z) (unit: percent), the relational expression of 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1 is satisfied.

  When X-ray diffraction is performed on the hardened layer 11, a diffraction peak occurs at an angle θ1 corresponding to a specific crystal plane of the martensite phase. In addition, when X-ray diffraction is performed on the hardened layer 11, the diffraction intensity is 1⁄2 of the diffraction peak value at an angle θ2 larger than the angle θ1 and an angle θ3 smaller than the angle θ1. The difference between the angle θ2 and the angle θ3 is the half width of the diffraction peak in the X-ray diffraction of the martensitic phase.

  The above specific crystal plane is preferably the {211} plane of the martensitic phase. The {211} plane of the martensitic phase means all planes that are crystallographically equivalent to the (211) plane of the martensitic phase. The X-ray used for this X-ray diffraction is preferably a CuKα ray. The X-ray diffraction is performed, for example, using MSF-3M manufactured by Rigaku Corporation.

  The volume ratio of the austenite phase in the quenched and hardened layer 11 and the area ratio of the carbide phase in the quenched and hardened layer 11 are measured by the following method. First, mirror polishing of the bearing component 10 according to the embodiment is performed. Second, the mirror polished surface is corroded. This corrosion is performed using a corrosive liquid (pyracles) containing picric acid and alcohol. Third, SEM (Scanning Electron Microscope) observation of the corroded mirror-polished surface is performed.

  Then, the area ratio of the austenite phase and the area ratio of the carbide phase in the quenched and hardened layer 11 are calculated by performing image analysis on the SEM image acquired from the mirror-polished surface which has been corroded. The area ratio of the austenite phase in the quenched and hardened layer 11 is regarded as the volume ratio of the austenite phase in the quenched and hardened layer 11.

(Configuration of rolling bearing according to the embodiment)
The configuration of the rolling bearing 100 according to the embodiment will be described below.

  The rolling bearing 100 according to the embodiment is, for example, a radial ball bearing. However, the rolling bearing 100 according to the embodiment is not limited to this. The rolling bearing 100 according to the embodiment may be a thrust ball bearing. The rolling bearing 100 according to the embodiment may be a radial roller bearing. The rolling bearing 100 according to the embodiment may be a thrust roller bearing. In the following, the case where the rolling bearing 100 according to the embodiment is a radial ball bearing will be described as an example.

  FIG. 4 is a cross-sectional view of the rolling bearing 100 according to the embodiment. As shown in FIG. 4, the rolling bearing 100 according to the embodiment includes an inner ring 20, an outer ring 30, rolling elements 40, and a cage 50. The inner ring 20, the outer ring 30, and the rolling elements 40 are made of steel. This steel is, for example, a bearing steel. This steel is preferably a high carbon chromium bearing steel defined in the JIS standard. More specifically, this steel is SUJ2 defined in the JIS standard.

  The inner ring 20 is a ring-shaped member. The inner ring 20 has a first raceway surface 20a. More specifically, the first raceway surface 20 a is constituted by the outer circumferential surface of the inner ring 20. A raceway groove is provided on the first raceway surface 20a. The outer ring 30 is a ring-shaped member. The outer ring 30 has a second raceway surface 30a. More specifically, the second raceway surface 30 a is constituted by the inner peripheral surface of the outer ring 30. A raceway groove is provided on the second raceway surface 30a. The inner race 20 and the outer race 30 are disposed such that the first raceway surface 20a and the second raceway surface 30a face each other. More specifically, the outer ring 30 is disposed outside the inner ring 20.

  The rolling element 40 is a spherical member. The rolling element 40 has a rolling surface 40 a. More specifically, the rolling surface 40 a is constituted by the surface of the rolling element 40. The rolling element 40 is disposed between the inner race 20 and the outer race 30 so as to be sandwiched between the raceway groove provided on the first raceway surface 20a and the raceway groove provided on the second raceway surface 30a.

  Although not shown in FIG. 4, a quench-hardened layer 11 is provided on at least one of the first raceway surface 20 a, the second raceway surface 30 a, and the rolling surface 40 a. That is, at least one of the inner ring 20, the outer ring 30, and the rolling element 40 is the bearing component 10 according to the embodiment. The quench hardened layer 11 is the same as the quench hardened layer 11 of the bearing component 10 according to the embodiment.

  That is, the quench hardened layer 11 provided on the first raceway surface 20a, the second raceway surface 30a, and the rolling surface 40a includes a martensite phase, an austenite phase, and a carbide phase, and the quench hardened layer 11 The half-width in X-ray diffraction of martensite phase in X is X (unit: °), the volume ratio of austenite phase in quench-hardened layer 11 is Y (unit: percent), of carbide phase in quench-hardened layer 11 When the area ratio is Z (unit: percent), the relational expression of 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1 is satisfied.

  The holder 50 is made of, for example, a synthetic resin. The holder 50 is a ring-shaped member. The holder 50 is provided with a through hole. The through hole penetrates the cage 50 from the inner peripheral surface side toward the outer peripheral surface side. The through holes are arranged at a predetermined pitch in the circumferential direction of the holder 50. The cage 50 is disposed between the inner race 20 and the outer race 30 so as to be sandwiched between the first raceway surface 20 a and the second raceway surface 30 a. Rolling elements 40 are disposed in the through holes. Thus, the rolling elements 40 are arranged at a predetermined pitch along the circumferential direction.

(Method of manufacturing bearing component according to the embodiment)
Hereinafter, a method of manufacturing the bearing component 10 according to the embodiment will be described.

  FIG. 5: is process drawing which shows the manufacturing method of the bearing components 10 which concern on embodiment. As shown in FIG. 5, the method of manufacturing the bearing component 10 according to the embodiment includes a preparation process S10, a quenching process S20, a tempering process S30, and a post-treatment process S40.

  In preparation process S10, the workpiece member used as bearing component 10 which concerns on embodiment is prepared by passing through hardening process S20 and tempering process S30. The processing target member is a steel ring-shaped member. This steel is, for example, a bearing steel. The steel is preferably a high carbon chromium bearing steel defined in JIS. More specifically, this steel is preferably SUJ2 defined in JIS.

The quenching step S20 has a heating step S21 and a cooling step S22. In the heating step S21, the member to be processed is heated to a temperature equal to or higher than the A ₁ transformation point (hereinafter referred to as "heating temperature"). The A ₁ transformation point is the temperature at which the ferrite phase in the steel starts to transform to the austenite phase. In the heating step S21, after the processing target member is heated to the heating temperature, the heating temperature is maintained for a predetermined time (hereinafter, referred to as "holding time"). The heating temperature is preferably 900 ° C. or more and 1000 ° C. or less. The heating temperature is more preferably 900 ° C. or more and 950 ° C. or less. This heating is performed by induction heating using, for example, a single turn coil.

  As the holding time lengthens, or as the heating temperature increases, the amount of carbon dissolved in the base material of the steel material constituting the member to be processed in the heating step S21 increases. Therefore, the area ratio of the carbide phase in the quenched and hardened layer 11 can be controlled by controlling the holding time and the heating temperature.

  As the amount of solid solution of carbon in the martensitic phase in the steel increases, the c-axis of the martensitic crystal extends. Therefore, the half value width of the diffraction peak in the X-ray diffraction of the martensitic phase tends to be large. The solid solution amount of carbon in the martensitic phase in the steel material tends to increase as the retention time is lengthened or as the heating temperature is raised. Therefore, by controlling the holding time and the heating temperature, it is possible to control the diffraction peak in the X-ray diffraction of the martensitic phase.

  As described above, the longer the holding time or the higher the heating temperature, the more the carbon tends to form a solid solution in the steel material. As the solid solution amount of carbon in the steel material increases, the austenite phase which remains without being transformed to the martensitic phase after the cooling step S22 tends to increase. Therefore, the volume ratio of the austenite phase in the quenched and hardened layer 11 can be controlled by controlling the holding time and the heating temperature.

In the cooling step S22, the processing target member is cooled. In the cooling step S22, the processing target member is cooled from the heating temperature to a temperature equal to or lower than the _MS point of the steel forming the processing target member (hereinafter referred to as "cooling temperature"). The M 2 _S point is the temperature at which the austenitic phase begins to transform to the martensitic phase. Cooling of the processing target member in the cooling step S22 is performed using any known refrigerant. The refrigerant used for cooling the processing target member is, for example, oil or water.

  The cooling temperature and the cooling rate in the cooling step S22 are the amounts of the austenite phase in the steel material formed in the heating step S21 to be the martensite phase in the cooling step S22 (in other words, after the cooling step S22 Also affect the amount of remaining austenite phase). Therefore, the volume ratio of the austenite phase in the quenched and hardened layer 11 can be controlled also by controlling the cooling temperature and the cooling rate.

In the tempering step S30, the steel constituting the processing target member is tempered. The tempering of the processing target member holds the processing target member at a temperature below A ₁ point (hereinafter referred to as “tempering temperature”) for a predetermined time (hereinafter referred to as “tempering time”). It is done by. The tempering temperature is, for example, 180 ° C. The tempering time is, for example, 2 hours.

  In the tempering step S30, the austenite phase which has not become a martensitic phase even in the cooling step S22 is decomposed into a ferrite phase and a carbide phase. The amount of the austenite phase decomposed into the ferrite phase and the carbide phase changes by controlling the tempering temperature and tempering time. Therefore, the volume ratio of the austenite phase in the quenched and hardened layer 11 can be controlled by controlling the tempering time and the tempering time.

  In the post-processing step S40, post-processing is performed on the processing target member. In the post-processing step S40, for example, cleaning of the processing target member, machining of the processing target member, grinding, polishing and the like are performed. Thus, the bearing component 10 is manufactured.

(Evaluation of dimensional change rate and static load capacity)
Below, the evaluation test of the dimensional change rate and static load capacity performed with respect to the sample 1-sample 9 is demonstrated.

<Composition of steel materials>
Table 1 shows the compositions of the steel materials used in Samples 1 to 9. Although not shown in Table 1, iron (Fe) constitutes the balance of the steel material. As shown in Table 1, the steel materials used in Samples 1 to 9 are SUJ2 defined in JIS.

<Shape and size of sample>
Samples 1 to 9 are ring-shaped members. The dimensions of this ring-shaped member are: outer diameter 60.3 mm, inner diameter 53.7 mm, width 15.3 mm.

<Heat treatment conditions>
Table 2 shows the heat treatment conditions of the heat treatment performed on Samples 1 to 9. As shown in Table 2, in the samples 1 to 9, the heating temperature in the heating step S21 was set to 900 ° C., 950 ° C., or 1000 ° C.

  In Samples 1 to 9, the quenching step S20 and the tempering step S30 were performed such that the area ratio (Z) of carbides in the quenched and hardened layer 11 was 4 percent, 8 percent or 12 percent. .

<Method for evaluating dimensional change rate>
In the evaluation test of the dimensional change rate, the samples 1 to 9 were polished to test pieces having dimensions of an outer diameter of 60 mm, an inner diameter of 54 mm, and a width of 15 mm. After this polishing, each test piece was held at 230 ° C. for 2 hours in the air. After this holding, the dimensional change of each test piece was measured. The dimensional change rate was measured at two positions 90 ° apart from one another for each test piece. The dimensional change was taken as the average of three test pieces for each sample. When the dimensional change rate was 6 × 10 ⁻⁴ or less, it was evaluated as “OK”, and when it exceeded 6 × 10 ⁻⁴ , it was evaluated as “NG”.

<Static load capacity evaluation test method>
In the static load capacity evaluation test, samples 1 to 9 were formed into test pieces of 6 mm × 15 mm × 3 mm by wire cutting and then mirror-polished to be made test pieces. The static load capacity evaluation test is the depth of indentation caused by plastic deformation when a ceramic ball 3/8 inches in diameter is pressed with a constant load on the 6 mm x 15 mm surface of each test piece subjected to mirror polishing. It was done by measuring the The load for pressing the ceramic ball is 471N. This load corresponds to the case where _{Pmax of} the Hertzian contact is 4 GPa. The depth of the indentation was taken as the average value of 3 test pieces for each sample. In addition, the case where the depth of the indentation was 0.20 μm or less was evaluated as “OK”, and the case where it exceeded 0.20 μm was evaluated as “NG”.

  In addition, in order to evaluate the relationship between the results of the dimensional change rate evaluation test and the static load capacity evaluation test and the metal structures of the samples 1 to 9, the austenite phase in the quenched and hardened layer 11 for the samples 1 to 9 The measurement of the volume ratio (Y) of and the full width at half maximum (X) in X-ray diffraction of the martensitic phase was performed. The measurement of the half value width in the X-ray diffraction of the martensitic phase was performed using CuK alpha rays for the {211} plane of the martensitic phase. The half width (X) in the X-ray diffraction of the martensite phase, the volume ratio (Y) of the austenite phase in the quenched and hardened layer 11, and the area ratio (Z) of the carbide phase in the quenched and hardened layer 11 are all 0. "OK" is evaluated when the relationship between 064 × Y + 0.002 × Z <1 and 0.43 × X-0.15 × Y> 1 is satisfied, and when this relationship is not satisfied, "NG" It was evaluated.

<Test result>
Table 3 shows the results of the dimensional change rate evaluation test and the static load capacity evaluation test for Samples 1 to 9.

  As shown in Table 3, for the samples 1 to 4, the results of the dimensional change evaluation test and the results of the static load capacity evaluation test were both “OK”. On the other hand, for samples 5 to 9, at least one of the dimensional change rate evaluation test result and the static load capacity evaluation test result was “NG”.

  Table 3 also shows the half width (X) in the X-ray diffraction of the martensitic phase, the volume ratio (Y) of the austenitic phase in the quenched and hardened layer 11 and the quenched and hardened layer 11 in the samples 1 to 9. It is shown whether the area ratio (Z) of the carbide phase in the above satisfies 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1.

  As shown in Table 3, for samples 1 to 4, the half width (X) in the X-ray diffraction of the martensitic phase, the volume ratio (Y) of the austenitic phase in the quenched and hardened layer 11, and the quenched and hardened layer 11 While the area ratio (Z) of the carbide phase in it satisfies the relationship of 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1, Samples 5 to 9 For this, this relationship was not fulfilled.

  From this, the half width (X) in the X-ray diffraction of the martensite phase, the volume ratio (Y) of the austenite phase in the quenched and hardened layer 11, and the area ratio (Z) of the carbide phase in the quenched and hardened layer 11 are as follows. , 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1, the dimensional stability and static characteristics of the bearing component 10 according to the embodiment are satisfied. Dynamic load capacity is shown to be improved.

(Effects of bearing component, rolling bearing, and method of manufacturing bearing component according to the embodiment)
As the amount of carbon in the martensitic phase increases, crystals of the martensitic phase extend in the c-axis direction, and the lattice strain of the martensitic phase increases. As a result, while the half value width in X-ray diffraction of a martensitic phase becomes large, the hardness of a martensitic phase rises and the hardness of quench hardening layer 11 rises (static load capacity of bearing parts 10 concerning an embodiment) Improve).

  However, in order to increase the amount of carbon in the martensitic phase, it is necessary to increase the heating time or to prolong the holding time. When the heating time is increased or the holding time is lengthened, the amount of the carbide phase in the quenched and hardened layer 11 decreases and the amount of the austenite phase formed in the heating step S21 increases. As a result, the amount of austenite phase (residual austenite) in the quench hardened layer 11 remaining without being transformed to the martensitic phase also by the cooling step S22 increases, and the dimensional stability of the bearing component 10 according to the embodiment decreases. Resulting in.

  Thus, since there is a trade-off relationship between static load capacity and dimensional stability, the half width in X-ray diffraction of the martensitic phase, the volume ratio of the austenitic phase in the quenched and hardened layer 11, and the quenching If the area ratio of the carbide phase in the incoming hardening layer 11 is not appropriately controlled, the static load capacity and the dimensional stability of the bearing component 10 according to the embodiment can not be compatible.

  As described above, in the bearing component 10 according to the embodiment, the half width (X) in the X-ray diffraction of the martensite phase, the volume ratio (Y) of the austenite phase in the quench hardened layer 11, and the quench hardened layer 11 The area ratio (Z) of the carbide phase in 4 satisfies the relationship of 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1. From the above test results, when this relationship is satisfied, static load capacity can be improved while maintaining dimensional stability. Therefore, according to the bearing component 10 according to the embodiment, both dimensional stability and static load capacity can be achieved.

  As described above, in the rolling bearing 100 according to the embodiment, at least one of the first raceway surface 20a, the second raceway surface 30a, and the rolling surface 40a is provided with the quench-hardened layer 11. Therefore, according to the rolling bearing 100 which concerns on embodiment, dimensional stability and static load capacity can be made to make compatible.

  Although the embodiments of the present invention have been described as above, various modifications of the above-described embodiments are possible. Further, the scope of the present invention is not limited to the above-described embodiment. The scope of the present invention is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

  The above embodiments are particularly advantageously applied to a bearing component, a method of manufacturing the same, and a rolling bearing using the bearing component.

  10 bearing parts, 10a upper surface, 10b bottom surface, 10c inner peripheral surface, 10d outer peripheral surface, 11 hardened layer, 20 inner ring, 20a first raceway surface, 30 outer ring, 30a second raceway surface, 40 rolling elements, 40a rolling Surface, 50 cage, 100 rolling bearing, A central axis, S10 preparation process, S20 hardening process, S21 heating process, S22 cooling process, S30 tempering process, S40 post-treatment process.

Claims (5)

A steel bearing component having a quench hardened layer on its surface,
The quench hardened layer includes a martensite phase, an austenite phase, and a carbide phase,
The half width in X-ray diffraction of the martensite phase is X (unit: °), the volume ratio of the austenite phase in the quench hardened layer is Y (unit: percent), the carbide phase in the quench hardened layer Bearing parts in which the relationship between 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1 is satisfied, where Z (unit: percent) is the area ratio of .   The bearing component according to claim 1, wherein the half width is a half width of a diffraction peak of {211} plane of the martensitic phase by CuKα ray.   The bearing component according to claim 1, wherein the steel is SUJ 2 defined in JIS standard. The dimensional change of the quenched and hardened layer is 6 × 10 ⁻⁴ or less,
The indentation depth at the time of pressing the ceramic ball of 3/8 inch in diameter with the load of 471 N to the said quenching-hardening layer will be 0.2 micrometer or less, It is any one of Claims 1-3. Bearing parts. A steel inner ring having a first raceway surface,
A steel outer ring having a second raceway surface and disposed such that the second raceway surface faces the first raceway surface;
And a steel rolling element disposed between the inner ring and the outer ring and having a rolling surface,
A hardened hardened layer is provided on at least one of the first raceway surface, the second raceway surface, and the rolling surface.
The quench hardened layer includes a martensite phase, an austenite phase, and a carbide phase,
The half width in X-ray diffraction of the martensite phase is X (unit: °), the volume ratio of the austenite phase in the quench hardened layer is Y (unit: percent), the carbide phase in the quench hardened layer A rolling bearing satisfying 0.064 × Y + 0.002 × Z <1 and 0.43 × X−0.15 × Y> 1 where an area ratio of Z is a unit (percent).

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