JPH08233755A - Method and apparatus of x-ray diffraction for tubular sample - Google Patents

Abstract

PURPOSE: To evaluate the local or average crystal structure on the circumference of the outer surface of a tubular sample using an X-ray diffractometer. CONSTITUTION: The optical system in a diffractometer comprises an incident system including an X-ray source 16, a solar slit 17 for limiting vertical divergence, a wide divergence slit 18, etc., and a light receiving system including a sample stage 13, a tubular sample 19, a thin slit 20 for limiting lateral scattering, a thin solar slit 21 for limiting lateral divergence, a thin slit 22 for limiting lateral scattering, etc., and an X-ray detector 23. Contact line 26 of the tubular sample 19 is aligned with the θ-axis of the diffractometer and an X-ray beam is projected to the outer surface of the tubular sample 19 in order to detect the X-ray diffracted only on the contact line 26 thus obtaining local or average information related to the crystal structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray diffraction method and apparatus for analyzing a local or average crystal structure on the circumference of the outer surface of a cylindrical sample having arbitrary inner and outer diameters. Regarding

[0002]

2. Description of the Related Art In various industrial machines, so-called high performance and severe usage conditions have been encountered when operating under high speed, high pressure, high temperature or low temperature atmosphere. For this reason, for example, in laying rails, rolling rolls, and bearings of machines, it is not possible to deal with such usage conditions with only conventional materials, and improvement of materials or development of new materials is an essential requirement. .

In such material research, a rotary rolling test between a cylindrical test piece fixed to one drive shaft and a cylindrical test piece fixed to a free shaft has been widely performed, and its contact surface, that is, a cylinder. There has been a strong demand for nondestructive measurement and analysis of the crystal structure of the outer surface of the test piece. A conventional focused X-ray diffractometer has been used as a general-purpose instrument for crystal structure analysis of a flat sample.

Here, FIG. 9 shows a configuration example of a conventional X-ray diffractometer. As shown in this perspective view, the X-ray beam 2 emitted from the X-ray source 1 has a relatively large divergence angle that restricts the divergence in the vertical direction. And the divergence angle depends on the interval) and the flat sample 5 is irradiated through the divergence slit 4. In addition,
The divergence slit 4 controls the irradiation area of the X-ray beam 2 with respect to the flat sample 5, and is normally set wide so as to increase the irradiation area and increase the X-ray intensity.

Diffracted X-rays 6 from the flat sample 5 pass through a wide scattering slit 7 similar to the divergence slit 4 and a solar slit 8 having a relatively large divergence angle for limiting the divergence up and down and enter a light receiving slit 9. Then, the X-ray detector 10 concentrates on one point and is detected. That is, the reason why the flat sample is used in this way is to fully utilize the concentration effect of the diffracted X-rays 6 in the light-receiving slit 9, whereby the weak diffracted X-ray beam is concentrated at the position to be measured. , To increase the strength and obtain information on the average crystal structure.

[0006]

However, the optical system in the conventional apparatus cannot satisfy the X-ray beam concentration condition particularly for a cylindrical sample having a convex surface, and the crystal state of the sample is not satisfied. It was also impossible to detect the dependent diffracted X-rays. Furthermore, the conventional X-ray diffractometer does not include a sample stand that can detect diffracted X-rays from the outer surface of a cylindrical sample. For this reason, in the past, this has hindered material research for industrial machinery and the like.

An object of the present invention is to solve the above problems and to make it possible to evaluate a local or average crystal structure on the circumference of the outer surface of a cylindrical sample by an X-ray diffractometer. .

[0008]

According to an X-ray diffraction method of a cylindrical sample according to the present invention, the contact line of the cylindrical sample and the θ axis of the X-ray diffractometer are made to coincide with each other, and the X-ray is applied to the outer surface of the cylindrical sample.
A step of injecting a line beam; a step of detecting diffracted X-rays from only the contact line of the cylindrical sample; and a step of detecting local information about the crystal structure on the outer surface of the cylindrical sample from the detected diffracted X-rays. It is equipped with the step of seeking.

Further, in the X-ray diffraction method for a cylindrical sample according to the present invention, the cylindrical sample is rotated around its central axis, and diffracted X-rays are detected along the circumference of the outer surface of the cylindrical sample. The method further comprises steps to obtain average information on the crystal structure.

An X-ray diffraction apparatus for cylindrical samples according to the present invention is
A divergent X-ray beam is formed by having a solar slit that limits the divergence of X-rays emitted from the X-ray source and a wide slit that limits the irradiation area of the X-rays that should be incident on the cylindrical sample. The divergent beam incident system and the contact line on the outer surface of the cylindrical sample having an arbitrary outer diameter and inner diameter are made to coincide with the θ axis of the X-ray diffractometer, and the divergent X-ray beam is irradiated along the contact line. And a slit slit for limiting upper and lower divergence of the divergent diffracted X-ray beam from the cylindrical sample, a solar slit having a small divergence angle, and a slit slit, and the diffracted X-ray beam is applied to these slits. Through the parallel beam receiving system for detecting the diffracted X-rays from only the contact line of the cylindrical sample through, through controlling the driving and rotating position of the cylindrical sample, and detecting by the X-ray detector An arithmetic unit for analyzing the diffracted X-rays, in which and a display device for displaying a local or average information about the crystal structure of the cylindrical sample from the calculation result of the arithmetic unit.

Also, in the X-ray diffraction apparatus for cylindrical samples according to the present invention, the sample stage has a drive shaft of a drive motor attached to a bearing part coupled to a rotary shaft supported by the bearing part, A rotation mechanism configured to fix and support the cylindrical sample at one end thereof via a sample receiving plate and to rotate the cylindrical sample around its central axis so that the cylindrical sample can be stopped at an arbitrary position; and the diffract. A Y-axis stage that holds the bearing so as to move the central axis of the cylindrical sample in the Y direction parallel to the θ rotation axis of the meter, and the Y-axis stage that supports the cylindrical sample through the bearing. And an X-axis stage adapted to move in the X direction orthogonal to the central axis of the cylindrical sample, so that a desired portion on the outer surface of the cylindrical sample coincides with the θ rotation axis of the diffractometer. Move By doing so, the contact point to which the X-ray beam should be incident is set at the site of the outer surface.

Further, in the X-ray diffraction apparatus for cylindrical samples according to the present invention, the drive motor is fixed to the bearing portion by a metal fitting, and a slit plate and a photosensor are attached to the drive shaft to control the rotation and stop positions, Further, the drive shaft is coupled to the rotary shaft supported by the bearing portion via a coupling, and a sample receiving plate is mounted perpendicularly to the rotary shaft, and the sample receiving plate is attached via the sample receiving plate. A taper portion of the rotating shaft is provided, and a fixing groove for a holding metal fitting is provided along the central axis of the rotating shaft in the cross section of the tip of the taper portion, and a cylindrical sample having an inner diameter larger than the diameter of the bottom surface of the taper portion is provided. Place it on the sample receiving plate, fit the outer opening collet into the taper part, attach the holding metal fitting to the fixing groove to fix the cylindrical sample to the sample receiving plate, and rotate the cylindrical sample around the central axis. Rotate to Is a rotation mechanism configured to stop at an arbitrary position, a Y-axis stage that holds the bearing unit to move the central axis of the cylindrical sample in the Y direction parallel to the θ rotation axis of the diffractometer, Contact with the cylindrical sample that is movable in the X direction orthogonal to the central axis of the cylindrical sample integrated with the Y-axis stage and that is perpendicular to the X direction and coincides with the θ rotation axis of the diffractometer After the positioning metal fittings attached to the bracket surface of the length which is not in contact with the outer surface of the cylindrical sample to set the contact position, the positioning metal fittings are rotated by 90 ° to be fixed to the brackets. The sample stage is composed of an X-axis stage.

[0013]

According to the present invention, an X-ray beam is irradiated onto the outer surface of a cylindrical sample that continuously rotates or stands at an arbitrary position, and diffracted X-rays from only the contact line of the cylindrical sample are detected by a parallel beam receiving system. In addition, it is possible to analyze the average or local crystal structure by the arithmetic device and display the information on the display device.

Further, in the apparatus of the present invention, the X-ray emitted from the X-ray source is converted into a divergent X-ray beam through a solar slit having a large divergence angle which limits the divergence up and down or a wide slit which limits the irradiation area on the sample. Divergent beam injection system,
A cylindrical sample having an arbitrary outer and inner diameter irradiated with the divergent X-ray beam from the divergent beam incidence system, the contact point of the outer surface of the cylindrical sample and the θ axis of the diffractometer, and the cylindrical sample Rotate around or stop at an arbitrary position to make a divergent X-ray beam incident around the contact line on the outer surface of the cylindrical sample, and to limit the divergence of the divergent diffracted X-ray beam from the cylindrical sample to the left and right. Slit slit, slit solar slit with small divergence angle and slit, slit, slit, and high-resolution parallel beam reception that detects diffracted X-rays only from the contact line on the outer surface of a cylindrical sample with an X-ray detector. Control the rotation and stop position of the system and the cylindrical sample, and X
It is composed of a display device and an arithmetic device for analyzing and displaying the diffracted X-rays detected by the line detector.

According to the present invention, from the basic investigation, the outer surface of the cylindrical sample is irradiated with the divergent X-ray beam, and the diffracted X-ray from only the contact line in the divergent diffracted X-ray beam from the outer surface of the cylindrical sample. X-ray optical system capable of detecting X-rays, or a cylindrical sample having an arbitrary inner / outer diameter, is moved in the X-direction or Y-direction, installed at a position where diffracted X-rays can be detected, and rotated around the central axis. Provided is a sample table capable of stopping rotation at an arbitrary position. That is, by detecting diffracted X-rays only from the contact lines on the outer surface of a cylindrical sample having an arbitrary inner / outer diameter, information on the average or local crystal structure (crystal system, lattice constant, identification of substance, The quantity, texture, fatigue level, etc.) are now required.

Preferred embodiments of the method and apparatus for X-ray diffraction of a cylindrical sample according to the present invention will be described below with reference to FIGS. 1 to 8.

As shown in FIG. 1, the apparatus of the present invention is provided with a powerful X-ray generator 11, an X-ray diffractometer 12, a sample stage 13, an arithmetic unit 14 and a display unit 15 as its main components. There is.

2 and 3 are a plan view and a perspective view of an optical system in the X-ray diffractometer 12 according to the present invention. This optical system includes an X-ray source 16, an incident system including a solar slit 17 for limiting vertical divergence, a wide divergent slit 18 and the like, a sample stage 13, a cylindrical sample 19, and left and right scattering. Slit slit 2 to limit the
0, a slit solar slit 21 for limiting left and right divergence, a slit slit 22 for limiting left and right scattering, and the like, and an X-ray detector 23. That is, the optical system of the present invention comprises a divergent incidence system, a sample stage on which a cylindrical sample is mounted, and a high-resolution parallel beam receiving system.

The solar slit 17 has a structure in which thin metal plates are vertically and closely (in FIG. 2, normal to the drawing) close to each other and are evenly spaced. on the other hand,
The solar slit 21 is a structure in which thin metal plates are stacked laterally (in the plane of FIG. 2 or parallel direction in the drawing) close to each other at equal intervals. However, the gap is smaller than that of the solar slit 17.

In this optical system, the center of the X-ray 24 emitted from the X-ray source 16, the divergent X-ray beam 25 passing through the wide solar slit 17 and the wide divergent slit 18 is set on the sample stage 13. It is incident on the contact 26a (see FIG. 2) on the outer surface of the cylindrical sample 19 at the Bragg angle θ.
In this case, the incident X-ray other than on the generatrix 26 corresponding to the contact point 26a has a Bragg angle of θ ± Δθ because the outer surface of the cylindrical sample 19 is a convex curved surface (cylindrical surface). Therefore, in the parallel beam receiving system, the slit slit 20, the slit solar slit 21, the slit slit 22 and the X-ray detector 23 are installed at an angle of 2θ with respect to the center of the incident X-ray. On the contact line (bus line 26) on the outer surface of 19, the diffracted X-ray 27 can be detected only from the incident angle θ.

The slit slit 20 and the slit slit 2
Reference numeral 2 has the same width and shields scattered rays on the left and right. Further, at a position other than the contact point 26a on the outer surface of the cylindrical sample 19, since the X-ray beam is incident at the Bragg angle θ ± Δθ, it becomes divergent diffracted X-rays 27 ′ and 27 ″. 27 ′ and 27 ″ cannot reach the X-ray detector 23. Therefore, in the optical system of the present invention, unlike the conventional focusing diffractometer, the local diffraction X is generated only from the contact 26a on the outer surface of the cylindrical sample 19.
The line is detected. When the cylindrical sample 19 is continuously rotated around its central axis, an average diffracted X-ray along the circumference of the outer surface can be detected.

4 to 6 show examples of the structure of the sample table 13 according to the present invention. 4 is a front view thereof, FIG. 5 is a plan view thereof, and FIG. 6 is a side view at the time of adjusting the position of the cylindrical sample.
The sample table 13 includes a rotation mechanism for rotationally driving or stopping the cylindrical sample 19 around the central axis, and a cylindrical sample 19
X-ray stage 28 for moving the cylindrical sample 19 to a position for detecting the diffracted X-ray 27 from the contact line on the outer surface of the
And a Y-axis stage 29.

As shown in FIG. 4, the motor 30 has a metal fitting 31.
Is attached to the bearing box (bearing portion) 32 by
The bearing box 32 is fixed to the Y-axis stage 29.
A slit plate 34 and a photo sensor 35 are attached to the drive shaft 33 below the motor 30 to control the rotation and stop positions. On the other hand, the drive shaft 3 on the upper side of the motor 30
6 is coupled to a rotating shaft 39 supported by a bearing 38 via a coupling 37. A sample receiving plate 40 is vertically attached to the rotating shaft 39, and a taper portion 41 is provided on the sample receiving plate 40. A fixing groove 43 that engages with the press fitting 42 is provided along the axis of the rotating shaft 39 from the tip (upper end) of the taper portion 41.

Then, the sample receiving plate 4 in the tapered portion 41
The cylindrical sample 19 having an inner diameter larger than the bottom of the
The cylindrical sample 19 is fixed to the sample receiving plate 40 by placing it on the sample holder 0, fitting the outer opening collet 44 into the tapered portion 41, and inserting the holding metal fitting 42 into the fixing groove 43. Therefore,
This rotating mechanism is controlled by the arithmetic unit 14 via the lead wire 45 of the motor 30 or the lead wire 46 of the photo sensor 35, and can rotate the cylindrical sample 19 and make it stand still at an arbitrary position.

Further, the Y-axis handle 4 of the Y-axis stage 29
By the operation of 7, the center of the rotating shaft 39, that is, the cylindrical sample 1
The rotating mechanism can move up and down along the central axis of 9. Further, the Y-axis stage 29 is coupled to the X-axis stage 28, and can be moved in the X direction orthogonal to the Y direction by operating the X-axis handle 48.

According to the X-axis stage 28, the X
By rotating the X-axis handle 48, the positioning metal fitting 51 attached to the outer surface of the bracket 50 which is perpendicular to the direction and in which the θ rotation axis 49 of the diffractometer 12 coincides, and the cylindrical sample 19 are rotated. The contact position on the outer surface of the cylindrical sample 19 on the sample table 13 can be set by the contact as shown in FIG. After that, FIG.
As shown in FIG. 7, the positioning metal fitting 51 is rotated 90 ° (see the dotted line in FIG. 6) and fixed to the bracket 50 having a length that does not contact the cylindrical sample 19.

As described above, in the apparatus of the present invention, the cylindrical sample 19 having an arbitrary inner / outer diameter is used as the X-axis stage 28 or the Y-axis stage 29.
Thus, the incident X-ray can be easily and accurately set to a position where irradiation or diffraction X-ray can be detected. The sample table 13 is fixed by inserting the jig 52 provided on the bottom of the X-axis stage 28 into the θ axis of the diffractometer 12.

Therefore, the apparatus of the present invention irradiates the outer surface of a cylindrical sample having an arbitrary inner / outer diameter that rotates or stops with incident X-rays, and measures diffracted X-rays only from the contact points on the outer surface. Then, it is analyzed by the arithmetic unit 14 and the result is displayed. Therefore,
Changes in the crystal structure of rolling rails, rolling rolls, bearing steel brake materials, etc. during rolling fatigue will be clarified, and improvement of fatigue resistant materials and development guidelines will be easily obtained.

Next, a specific example of measurement / analysis to which the present invention is applied will be described. In this example, the crystal structure of a conventional railroad rail is analyzed. In this type of railway rail, the cumulative tonnage (cumulative tonnage) is 10 billion tons, and the fatigue crack rapidly increases, and when it reaches about 30 billion tons, the crack may grow and break. It is considered that this is because deformation texture formation or fatigue progressed due to contact between the train wheels and the rail head surface. In order to clarify the change in the crystalline state of the rolling fatigue process of this rail, a laboratory experiment using a two-cylindrical contact rolling device was conducted.

This device has two rotating shafts, an A-axis on the driving side and a B-axis on the free side. The rotation speed and load of each axis are controlled by a computer. The experimental conditions are the contact load, the maximum Hertz pressure (the surface pressure when the wheel and the rail contact each other, which can be obtained from the Hertz equation), and the average tangential force in consideration of the running conditions of the conventional line. And lubrication were combined. In addition, since the existing wheels and rails have the same composition, a cylindrical sample (outer shape: 1
(00 mmφ, inner diameter: 20 mmφ, width: 30 mm) was prepared and attached to each shaft. Then, after reaching a predetermined cumulative tonnage, the cylindrical sample assuming a rail was removed from the B axis, and the crystal state was measured and analyzed by the apparatus of the present invention.

Then, the rolling fatigue test and the work of measurement / analysis by the apparatus of the present invention were repeated until the cumulative ton was 40 billion tons. Two types of sample rotation methods were used for the measurement. That is, one is to continuously rotate a cylindrical sample in order to obtain an average crystal state, and perform a goniometer scan of θ-2θ to detect a diffracted X-ray. On the other hand, diffracted X-rays were detected by combining step rotation of a cylindrical sample and θ-2θ goniometer scanning in order to obtain a local crystalline state.

1) Diffracted X-rays when continuously rotated by the apparatus of the present invention are detected for cylindrical samples of each cumulative ton, and the intensity and width spread of the diffracted X-rays of each crystal orientation (parameter of nonuniform strain). The average texture and fatigue level were calculated from. FIG. 7 shows this result and shows the relationship between the deformation texture and the fatigue level with respect to the cumulative tonnage. And
The following points became clear. Due to the increase in the cumulative tonnage, the {110} orientation generated by the contact between the wheel and the rail decreases, and the {100} orientation of the deformation stable orientation develops. Fatigue degree (width expansion of diffracted X-rays in the {211} direction)
Has almost no change in cumulative tonnage up to 10 billion tons,
It has been rapidly increasing at more than 10 billion tons.

2) The cumulative tonnage in which fatigue cracks are recognized is 3
With respect to a cylindrical sample of 5 billion tons, the diffracted X-rays when the step scanning was performed were detected, and the local texture and the fatigue degree were obtained from the diffracted X-ray intensity and the width spread of each crystal orientation. FIG. 8 shows this result, and shows the relationship between the deformation texture and the fatigue level with respect to the outer circumference of the cylindrical sample. And the following points became clear. Non-uniform texture is formed on the outer surface of the cylindrical sample, especially in the vicinity of the crack {100} of deformed texture.
The azimuth was well developed. Fatigue progressed more markedly in the vicinity of the crack than in other places.

As described above, it has been found that the cracks caused by rolling fatigue of the rail are closely related to the formation of texture and the accumulation of non-uniform strain. Then, it was revealed that it is important to suppress the formation of {100} texture in the rolling fatigue resistant material.

[0035]

As described above, according to the X-ray diffraction method for a cylindrical sample of the present invention and the apparatus therefor, the crystal structure state of fatigue processes of rolling rolls, bearing materials, brake materials, etc. as well as laying rails is clarified. Since it can be used for the improvement and development of fatigue resistant materials, the effect is great.

[Brief description of drawings]

FIG. 1 is a diagram showing a main configuration of an X-ray diffraction apparatus in an example of the present invention.

FIG. 2 is a plan view of an optical system in an X-ray diffractometer according to the present invention.

FIG. 3 is a perspective view of an optical system in the X-ray diffractometer according to the present invention.

FIG. 4 is a front view showing a configuration example of a sample table according to the present invention.

FIG. 5 is a plan view showing a configuration example of a sample table according to the present invention.

FIG. 6 is a side view showing a configuration example of a sample table according to the present invention.

FIG. 7 is a graph showing an example of measurement / analysis results by the device of the present invention.

FIG. 8 is a graph showing an example of measurement / analysis results by the device of the present invention.

FIG. 9 is a diagram showing a main configuration of a conventional X-ray diffraction apparatus.

[Explanation of symbols]

 11 X-ray generator 12 X-ray diffractometer 13 Sample stand 14 Arithmetic device 15 Display device 16 X-ray source 17 Solar slit 18 Divergence slit 19 Cylindrical sample 20 Slit slit 21 Slit solar slit 22 Slit slit 23 X-ray detection 24 X-ray 25 Divergent X-ray beam 26 Busbar 28 X-axis stage 29 Y-axis stage 30 Motor 31 Metal fittings 32 Bearing box 34 Slit plate 35 Photo sensor 37 Coupling 38 Bearing 39 Rotating shaft 40 Sample receiving plate 42 Holding metal fitting 44 Outside opening Collet 45 Lead wire 46 Lead wire 47 Y-axis handle 48 X-axis handle 51 Bracket

Claims (5)

[Claims] 1. A step of causing an X-ray beam to be incident on an outer surface of the cylindrical sample by aligning a contact line of the cylindrical sample with a θ axis of an X-ray diffractometer, and Detecting diffracted X-rays, obtaining local information about the crystal structure on the outer surface of the cylindrical sample from the detected diffracted X-rays,
An X-ray diffraction method for a cylindrical sample, comprising: 2. The X-ray diffraction method according to claim 1, wherein the cylindrical sample is rotated around its central axis, and diffracted X-rays are detected along the circumference of the outer surface of the cylindrical sample. An X-ray diffraction method for a cylindrical sample, further comprising the steps of: obtaining average information about a crystal structure. 3. A divergent X-ray beam is provided with a solar slit for limiting the divergence of X-rays emitted from an X-ray source and a wide slit for limiting the irradiation area of X-rays to be incident on a cylindrical sample. The divergent beam incident system so formed is aligned with the contact line on the outer surface of the cylindrical sample having an arbitrary outer diameter and inner diameter, and the θ axis of the X-ray diffractometer, and the divergence X along the contact line. A sample stage adapted to irradiate a beam of rays, a slit slit for limiting the vertical divergence of the divergent diffracted X-ray beam from the cylindrical sample, a solar slit having a small divergence angle, and a slit slit. Diffraction X
A parallel beam receiving system configured to detect a diffracted X-ray from only the contact line of the cylindrical sample through a line beam; and a driving and rotating position of the cylindrical sample, and X
And a display device that displays a local or average information regarding a crystal structure of the cylindrical sample from a calculation result of the calculation device, the calculation device analyzing the diffracted X-ray detected by the line detector. X-ray diffractometer for cylindrical samples. 4. The X-ray diffractometer according to claim 3, wherein, in the sample stage, a drive shaft of a drive motor attached to a bearing unit is coupled to a rotary shaft supported by the bearing unit, At one end of
A rotation mechanism that fixes and supports the cylindrical sample via a sample receiving plate, and that can rotate the cylindrical sample around its central axis so that it can be stopped at an arbitrary position, and the θ rotation axis of the diffractometer. In the Y direction parallel to
A Y-axis stage that holds the bearing so as to move the central axis of the cylindrical sample; and a Y-axis stage that supports the cylindrical sample via the bearing, in the X direction orthogonal to the central axis of the cylindrical sample. And an X-axis stage adapted to be moved to a desired position on the outer surface of the cylindrical sample so as to coincide with the θ rotation axis of the diffractometer. An X-ray diffractometer for a cylindrical sample, wherein a contact point on which an X-ray beam should be incident is set. 5. The drive motor is fixed to the bearing portion with metal fittings, a slit plate and a photo sensor are attached to the drive shaft to control the rotation and stop positions, and the drive shaft is provided with the bearing through a coupling. Is connected to the rotating shaft supported by the shaft, a sample receiving plate is attached perpendicularly to the rotating shaft, and a taper portion of the rotating shaft is provided through the sample receiving plate. A fixing groove for the metal fitting is provided in the cross section of the tip along the central axis of the rotating shaft, and a cylindrical sample having an inner diameter larger than the diameter of the bottom surface of the taper portion is placed on the sample receiving plate and The outer opening collet is fitted to the portion, the pressing metal fitting is attached to the fixing groove to fix the cylindrical sample to the sample receiving plate, and the cylindrical sample is rotated around the central axis or stopped at an arbitrary position. Rotation mechanism A Y-axis stage that holds the bearing for moving the central axis of the cylindrical sample in the Y direction parallel to the θ rotation axis of the diffractometer; and a central axis of the cylindrical sample integrated with the Y-axis stage. A positioning metal piece that is movable in the X direction orthogonal to the X direction, and that is attached to a bracket surface that is perpendicular to the X direction and that has a length that does not come into contact with the cylindrical sample that coincides with the θ rotation axis of the diffractometer; The sample stage is composed of an X-axis stage which is brought into contact with the outer surface of the cylindrical sample to set a contact point, and then the positioning metal fitting is rotated by 90 ° to be fixed to the bracket. The X-ray diffractometer according to claim 3, wherein