JP6055970B2 - Surface hardness evaluation method using X-ray diffractometer and X-ray diffractometer - Google Patents

Description

  The present invention relates to a method for evaluating the surface hardness of an object using an X-ray diffractometer that forms an X-ray diffraction image by irradiating the object with X-rays and diffracting the object with X-rays. The present invention also relates to an X-ray diffraction measurement apparatus provided with an arithmetic device for executing the evaluation method.

  Conventionally, in order to evaluate the hardness of the surface of a metallic object that has been subjected to a predetermined treatment or the hardness of the surface of a metallic object that has passed the years, the hardness of the surface has been measured by various methods. . Among these evaluation methods, as a method capable of nondestructively evaluating the surface hardness, there is a method using X-ray diffraction as shown in Patent Document 1 or Patent Document 2, for example. This method irradiates an object of a metallic object with X-rays, forms an X-ray diffraction image by diffracted X-rays generated at the object, and a characteristic value based on the intensity distribution of the diffracted X-rays of the formed image ( This is a method for obtaining the surface hardness using the relationship between the characteristic value and the surface hardness obtained in advance. This method has an advantage that the hardness of the surface can be evaluated without damaging the object and the evaluation can be performed in a short time.

JP-A-6-347425 JP 2007-271600 A

  However, there are some problems in the method for evaluating the surface hardness of an object using X-ray diffraction. The first problem is that a normal diffraction X-ray intensity distribution may not be obtained due to large crystal grains of the object, and the surface hardness of the object may not be obtained accurately. This is a problem. The second problem is that the characteristic value based on the intensity distribution of the diffracted X-rays is an X-ray intensity, an X-ray irradiation time, an X-ray incident angle, and an X-ray irradiation point where an X-ray diffraction image is formed. Even when an X-ray diffraction image is formed with all the parameters that may affect the characteristic value such as the distance to the same being formed, the variation in the characteristic value is large. That is, the problem is that the surface hardness of the object cannot be obtained with high accuracy by several measurements, and if it is attempted to improve the accuracy by obtaining an average value by measuring many times, the measurement takes time. It is. The third problem is that if the shape of the object is a complicated shape such as a gear, the X-ray incident angle must be set to an appropriate angle in order to obtain an X-ray diffraction image. When the incident angle is changed, the intensity distribution of the diffracted X-rays and the characteristic value based on the distribution also change, and the surface hardness of the object cannot be obtained with high accuracy.

  The present invention has been made to solve this problem, and an object of the present invention is to use an X-ray diffractometer that forms an X-ray diffraction image by irradiating an object with X-rays and diffracting the object with X-rays. In the method for evaluating the surface hardness of an object, the surface hardness of the object can be obtained with high precision by forming an X-ray diffraction image once, and the surface of the object can be accurately obtained without making the incident angle of X-rays constant. An object of the present invention is to provide a surface hardness evaluation method capable of obtaining hardness. And it is providing the X-ray-diffraction measuring apparatus provided with the arithmetic unit which performs this evaluation method in an apparatus.

In order to achieve the above object, the present invention is characterized by an X-ray emitter that emits X-rays toward an object to be measured, and an X-ray emitted from the X-ray emitter toward the object to be measured. The X-ray diffracted light generated at the measurement object is received by an imaging surface perpendicular to the optical axis of the X-ray emitted from the X-ray emitter, and X-ray diffraction is performed on the imaging surface. In the method for evaluating the surface hardness of an object to be measured using an X-ray diffractometer having a diffraction ring forming means for forming a diffraction ring that is an image of light, a diffraction ring forming step for forming the diffraction ring by the diffraction ring forming means And a diffraction ring intensity distribution detection step for detecting an intensity distribution corresponding to the intensity of X-ray diffracted light in the diffraction ring formed by the diffraction ring formation step, and an intensity distribution detected by the diffraction ring intensity distribution detection step. Based on the intensity distribution in the radial direction of the diffraction ring Which is the brute wide diffraction ring width is calculated at a plurality of points of diffraction ring, a diffraction ring width change curve calculation step of calculating a variation curve for the circumferential direction of the diffraction rings of the diffraction ring width, the diffraction ring width change curve calculating step The diffraction ring width average step for calculating the average value of the diffraction ring width and the average value of the diffraction ring width obtained by the diffraction ring width average step are acquired in advance from the change curve of the diffraction ring width calculated by It is to perform a surface hardness calculation step of calculating the surface hardness of the measurement object using the relationship between the diffraction ring width and the surface hardness.

According to this, since the diffractive ring width is calculated and averaged at all points over the entire circumference of the diffractive ring, variations in the diffractive ring width can be reduced and accurate surface hardness is obtained. be able to. Furthermore, the inventor measured the diffraction ring width by changing the incident angle of the X-ray with respect to the object. Even if the change curve of the diffraction ring width with respect to the circumferential direction of the diffraction ring changes depending on the incident angle of the X-ray. It was found that the average value of the diffraction ring width calculated from the change curve of the diffraction ring width did not change. We also found that this can be explained theoretically. This theoretical explanation will be given in the form for carrying out the invention. That is, according to this, the surface hardness of the object can be obtained with high accuracy without making the incident angle of X-rays constant.

  Another feature of the present invention is that the diffraction ring width averaging step calculates a parameter in the reference change curve when the reference change curve whose curve shape is set in advance with the calculated change curve most closely, The average value of the diffraction ring width is calculated from the calculated parameters.

  According to this, even if the diffracted X-ray is obstructed due to the measurement object having a complicated shape, etc., and even if a part of the diffraction ring is missing, the reference change that most closely matches the calculated change curve If the parameters of the curve are obtained, the average value of the diffraction ring width can be obtained with high accuracy, and the surface hardness with high accuracy can be obtained. The inventor has found that it can theoretically be explained that the shape of the change curve of the diffraction ring width with respect to the circumferential direction of the diffraction ring is a sine curve. In addition, it was confirmed that the result of measuring the change curve of the diffraction ring width with respect to the circumferential direction of the diffraction ring for a plurality of objects was also the same.

  Another feature of the present invention is that, in the diffraction ring width change curve calculation step, after calculating the change curve, the deviation of the calculated curve shape of the change curve from the curve shape of the reference change curve is calculated and calculated. The point where the deviation exceeds a preset allowable value is to be excluded from the calculated change curve.

  According to this, even if there is an abnormal part in the change curve of the diffractive ring width with respect to the circumferential direction of the diffractive ring, the diffractive ring width is calculated from the parameters of the reference change curve that most closely matches after automatically excluding the part. Therefore, the average value of the diffraction ring width can be obtained with high accuracy in a short time, and the surface hardness with high accuracy can be obtained.

  Another feature of the present invention is that the diffraction ring forming step is performed after the incident angle of the X-ray from the X-ray emitter to the measurement object is set to 10 degrees or more, and is detected by the diffraction ring intensity distribution detection step. The shape of the diffraction ring is detected on the basis of the intensity distribution, and the residual stress calculation step of calculating the residual stress of the measurement object using the cos α method from the detected shape of the diffraction ring is performed. According to this, an object can be evaluated not only by surface hardness but also by residual stress.

  Furthermore, the implementation of the present invention is not limited to the surface hardness evaluation method using the X-ray diffractometer, but is an X equipped with an arithmetic device for executing the above-described surface hardness evaluation method by a program. The invention can also be implemented as an invention of a line diffraction measuring apparatus.

1 is an overall schematic diagram showing an X-ray diffraction measurement system including an X-ray diffraction measurement apparatus used in an embodiment of the present invention. It is an enlarged view of the X-ray-diffraction measuring apparatus of FIG. It is a fragmentary sectional view which expands and shows the part through which the X-ray passes in the X-ray-diffraction measuring apparatus of FIG. It is an expansion perspective view of the plate part of FIG. It is a figure which shows the image imaged with the camera function of a X-ray-diffraction measuring apparatus with the optical axis of LED light, and the optical axis of an imaging lens. It is process drawing when measuring the surface hardness of a target object using an X-ray-diffraction measuring apparatus. It is a figure which shows the intensity distribution and half value width of the diffraction X-ray of the radial direction of a diffraction ring. It is a figure which shows the change curve of the half value width with respect to the circumferential direction of a diffraction ring for every incident angle of an X-ray. It is a figure which shows the relationship between a half value width and the surface hardness of a target object. It is a figure explaining the reason which the relationship of FIG. 8 arises. It is a figure for demonstrating the reason which the relationship of FIG. 8 arises using numerical formula, and is the figure which expanded the X-ray irradiation point and was seen from the upper direction. It is a figure for demonstrating the reason which the relationship of FIG. 8 arises using numerical formula, and is the figure which expanded the X-ray irradiation location and was seen from the horizontal direction. It is a figure for demonstrating the reason which the relationship of FIG. 8 arises using numerical formula, and is the figure which exaggerated the cross-sectional diameter of the emitted X-ray, and showed the width | variety of the diffraction X-ray. It is a figure for demonstrating the reason which the relationship of FIG. 8 arises using numerical formula, and is the figure which showed the diffraction ring and X-ray irradiation point when an X-ray incident angle is 0 degree by the orthogonal coordinate. It is a figure for demonstrating the reason which the relationship of FIG. 8 arises using numerical formula, and is the figure which showed the diffraction ring and X-ray irradiation point when an X-ray incident angle was made into the predetermined angle by the orthogonal coordinate.

  A configuration of an X-ray diffraction measurement system including an X-ray diffraction measurement apparatus used in an embodiment of the present invention will be described with reference to FIGS. In order to measure and evaluate the surface hardness and residual stress of the measurement object OB, this X-ray diffraction measurement system irradiates the measurement object OB with X-rays and emits the X-ray from the measurement object OB. A diffraction ring is formed by the diffracted X-rays generated, and the calculation processing is performed by detecting the intensity distribution of the diffracted X-rays of the formed diffraction ring. In the present embodiment, the measurement object OB is an iron member.

  The X-ray diffraction measurement apparatus includes an X-ray emitter 10 that emits X-rays, a table 16 for mounting an imaging plate 15 on which a diffraction ring is formed by diffracted X-rays, and a table drive mechanism 20 that rotates and moves the table 16. And a laser detector 30 for measuring the shape of the diffraction ring formed on the imaging plate 15, and these X-ray emitter 10, imaging plate 15, table 16, table driving mechanism 20 and laser detector 30. And a housing 50 to be used. The X-ray diffraction measurement system includes an object setting device 60 on which a measurement object OB is set, a computer device 90, and a high-voltage power supply 95 together with the X-ray diffraction measurement device. The housing 50 also includes various circuits that are connected to the X-ray emitter 10, the table 16, the table driving mechanism 20, and the laser detection device 30 to control operation and input detection signals. In FIG. 1, various circuits indicated by a two-dot chain line shown outside the casing 50 are accommodated within a two-dot chain line in the casing 50. In FIG. 1 and FIG. 2, circuit boards, electric wires, fixtures, air cooling fans, and the like are omitted.

  The casing 50 is formed in a substantially rectangular parallelepiped shape, and includes a bottom wall 50a, a front wall 50b, a rear wall 50e, a top wall 50f, a side wall (not shown), and corners of the bottom wall 50a and the front wall 50b. It is formed to have a notch wall 50c and a connecting wall 50d provided so as to be cut out from the front side to the back side of the sheet. The notch wall 50c is composed of a flat plate perpendicular to the bottom wall 50a and a parallel plate, and the connecting wall 50d is perpendicular to the side wall and has a predetermined angle with the bottom wall 50a. This predetermined angle is, for example, 30 to 45 degrees. A handle 51 for carrying the housing 50 is provided on the upper surface wall 50 f of the housing 50. On the side wall of the rear side of the casing 50 in the figure, a fixture that is fixed to a support rod 52 (not shown in FIG. 1) is provided. The casing 50 has a notch portion wall 50c that is an object setting device 60. It is fixed to the support rod 52 in the illustrated inclined state so as to be opposed to the upper surface. The support rod 52 is erected and fixed on an installation plate 53 formed in a flat plate shape placed on the installation surface.

  The object setting device 60 is configured by a so-called goniometer, and moves the stage 61 on which the measurement object OB is placed in the X, Y, and Z axis directions in the figure and around the X axis and the Y axis in the figure. Rotate (tilt). A height adjusting mechanism 63, first to fifth plates 64 to 68, and a stage 61 are sequentially placed from the bottom to the top on a flat plate-like installation plate 62 placed on the installation surface. . The height adjustment mechanism 63 has an operation element 63a, and moves the first plate 64 up and down (that is, moves in the Z-axis direction) relative to the installation plate 62 by rotating the operation element 63a. By changing the vertical distance between the first plates 64, the height of the first plate 64, that is, the height of the stage 61 is changed.

  An operating element 65a is assembled to the second plate 65, and the third plate 66 is rotated about the X axis with respect to the second plate 65 by a rotation operation of the operating element 65a via a mechanism (not shown). The inclination angle of the third plate 66 around the X axis relative to the second plate 65, that is, the inclination angle of the stage 61 around the X axis is changed. An operation element 66a is assembled to the third plate 66, and the fourth plate 67 is rotated around the Y axis with respect to the third plate 66 by a rotation operation of the operation element 66a via a mechanism (not shown). The inclination angle of the fourth plate 67 around the Y axis relative to the third plate 66, that is, the inclination angle of the stage 61 around the Y axis is changed. An operating element 67a is assembled to the fourth plate 67, and the fifth plate 68 is moved in the X-axis direction with respect to the fourth plate 67 by a rotation operation of the operating element 67a. The position of the fifth plate 68 in the X-axis direction with respect to the fourth plate 67, that is, the position of the stage 61 in the X-axis direction is changed. An operation element 68a is assembled to the fifth plate 68, and the stage 61 is moved in the Y-axis direction with respect to the fifth plate 68 by a rotation operation of the operation element 68a. The position of the fifth plate 68 in the Y axis direction, that is, the position of the stage 61 in the Y axis direction is changed. Further, the operating elements 65a and 66a can indicate the rotation angle (inclination angle) with a scale, and the rotating angle indicated by the operating element 65a increases when it rotates counterclockwise in the X-axis direction of FIG.

  The X-ray control circuit 71 is controlled by a controller 91 that configures a computer device 90 to be described later, and a high-voltage power supply 95 is supplied to the X-ray emitter 10 so that X-rays with a certain intensity are emitted from the X-ray emitter 10. The drive current and the drive voltage supplied from are controlled. In addition, the X-ray emitter 10 includes a cooling device (not shown), and the X-ray control circuit 71 also controls a drive signal supplied to the cooling device. Thereby, the temperature of the X-ray emitter 10 is kept constant.

  The table driving mechanism 20 includes a moving stage 21 below the X-ray emitter 10. The moving stage 21 is in the plane formed by the optical axis of the X-ray emitted from the X-ray emitter 10 and the normal line of the measurement object OB by the feed motor 22 and the screw rod 23, and the X-ray light. It can move in the direction perpendicular to the axis. The feed motor 22 is fixed in the table driving mechanism 20 and cannot move with respect to the housing 50. The screw rod 23 extends in a direction perpendicular to the optical axis of the X-ray emitted from the X-ray emitter 10, and one end thereof is connected to the output shaft of the feed motor 22. The other end portion of the screw rod 23 is rotatably supported by a bearing portion 24 provided in the table drive mechanism 20. The moving stage 21 is sandwiched between a pair of opposed plate-like guides 25 and 25 fixed in the table driving mechanism 20, respectively, and can move along the axial direction of the screw rod 23. ing. That is, when the feed motor 22 is driven forward or backward, the rotational motion of the feed motor 22 is converted into the linear motion of the moving stage 21. An encoder 22 a is incorporated in the feed motor 22. The encoder 22a outputs a pulse train signal that alternately switches between a high level and a low level to the position detection circuit 72 and the feed motor control circuit 73 each time the feed motor 22 rotates by a predetermined minute rotation angle.

  The position detection circuit 72 and the feed motor control circuit 73 start to operate in response to a command from the controller 91. Immediately after the start of measurement, the feed motor control circuit 73 drives the feed motor 22 to move the moving stage 21 to the feed motor 22 side. When the pulse train signal output from the encoder 22a is not input, the position detection circuit 72 outputs a signal indicating that the movement stage 21 has reached the movement limit position to the feed motor control circuit 73, and sets the count value to “0”. Set to. When the feed motor control circuit 73 receives a signal indicating that the movement limit position has been reached from the position detection circuit 72, the feed motor control circuit 73 stops outputting the drive signal to the feed motor 22. The above movement limit position is set as the origin position of the moving stage 21. Therefore, the position detection circuit 72 outputs a position signal representing “0” when the movable stage 21 moves in the upper left direction in FIGS. 1 and 2 and reaches the movement limit position, and the movement stage 21 moves to the movement limit position. When moving to the lower right, the pulse train signal from the encoder 22a is counted, and a signal indicating the movement distance x from the movement limit position is output as a position signal.

  When the feed motor control circuit 73 receives a set value indicating the position of the moving stage 21 from the controller 91, the feed motor control circuit 73 drives the feed motor 22 in the forward or reverse direction according to the set value. The position detection circuit 72 counts the number of pulses of the pulse signal output from the encoder 22a. Then, the position detection circuit 72 calculates the current position (movement distance x from the movement limit position) of the movement stage 21 using the counted number of pulses, and outputs it to the controller 91 and the feed motor control circuit 73. The feed motor control circuit 73 drives the feed motor 22 until the current position of the moving stage 21 input from the position detection circuit 72 matches the position of the moving destination input from the controller 91.

  Further, the feed motor control circuit 73 inputs a set value indicating the moving speed of the moving stage 21 from the controller 91. Then, the moving speed of the moving stage 21 is calculated using the number of pulses per unit time of the pulse signal input from the encoder 22a, and the calculated moving speed of the moving stage 21 becomes the moving speed input from the controller 91. The feed motor 22 is driven.

  The upper ends of the pair of guides 25 are connected by a plate-like upper wall 26. A through hole 26 a is provided in the upper wall 26, and the center position of the through hole 26 a faces the center position of the emission port 11 of the X-ray emitter 10. The line enters the table driving mechanism 20 through the emission port 11 and the through hole 26a.

  In a state where an imaging plate 15 to be described later is in the diffraction ring imaging position (the state shown in FIGS. 1 to 3), a through hole is provided at a position facing the through hole 26a of the moving stage 21 as shown in an enlarged view in FIG. 21a is formed. The moving stage 21 is assembled with a spindle motor 27 having an output shaft 27a whose center of rotation is the position of the central axis of the exit port 11 and the through holes 26a, 21a. The output shaft 27a is formed in a cylindrical shape and has a through-hole 27a1 having a circular cross section with the center of rotation as the central axis. On the opposite side of the spindle motor 27 from the output shaft 27a, a through hole 27b having the central position of the through hole 27a1 as a central axis is provided. A cylindrical passage member 28 for reducing the inner diameter of a part of the through hole 27b is fixed on the inner peripheral surface of the through hole 27b.

  An encoder 27c similar to the encoder 22a is incorporated in the spindle motor 27. The encoder 27c outputs, to the spindle motor control circuit 74 and the rotation angle detection circuit 75, a pulse train signal that is alternately switched between a high level and a low level every time the spindle motor 27 rotates by a predetermined minute rotation angle. Furthermore, the encoder 27c outputs an index signal that switches from the low level to the high level for a predetermined short period of time for each rotation of the spindle motor 27 to the controller 91 and the rotation angle detection circuit 75.

  The spindle motor control circuit 74 and the rotation angle detection circuit 75 start to operate in response to a command from the controller 91. The spindle motor control circuit 74 inputs a setting value representing the rotational speed of the spindle motor 27 from the controller 91. Then, the rotational speed of the spindle motor 27 is calculated using the number of pulses per unit time of the pulse signal input from the encoder 27c, and the calculated rotational speed becomes the rotational speed (set value) input from the controller 91. A drive signal is supplied to the spindle motor 27. The rotation angle detection circuit 75 counts the number of pulses of the pulse train signal output from the encoder 27c, calculates the rotation angle of the spindle motor 27, that is, the rotation angle θp of the imaging plate 15 using the count value, and sends it to the controller 91. Output. The rotation angle detection circuit 75 sets the count value to “0” when the index signal output from the encoder 27c is input. That is, the position where the index signal is input is the position where the rotation angle is 0 °. Note that the position of the imaging plate 15 at a rotation angle of 0 ° means that the laser beam is irradiated when an index signal is input when a diffraction ring formed on the imaging plate 15 is read by laser irradiation from a laser detection device 30 described later. It is a position that has been. This position is a line because it is at each radial position.

  The table 16 is formed in a circular shape, and is fixed to the tip of the output shaft 27 a of the spindle motor 27. The center axis of the table 16 coincides with the center axis of the output shaft of the spindle motor 27. The table 16 has a protrusion 17 that is provided integrally and protrudes downward from the center of the lower surface, and a thread is formed on the outer peripheral surface of the protrusion 17. The central axis of the protrusion 17 coincides with the central axis of the output shaft 27 a of the spindle motor 27. An imaging plate 15 is attached to the lower surface of the table 16. The imaging plate 15 is a circular plastic film whose surface is coated with a phosphor. A through-hole 15a is provided at the center of the imaging plate 15. By passing the protrusion 17 through the through-hole 15a and screwing a nut-shaped fixture 18 on the outer peripheral surface of the protrusion 17, the imaging plate 15 is fixed between the fixture 18 and the table 16. The fixture 18 is a cylindrical member, and a thread corresponding to the thread of the protrusion 17 is formed on the inner peripheral surface.

  The table 16, the projecting portion 17 and the fixture 18 are also provided with through holes 16a, 17a and 18a, respectively. The central axis of the through holes 16a, 17a and 18a is the same as the central axis of the table 16, and the through hole 18a. Is smaller than the through holes 16a and 17a, and is the same as the inner diameter of the passage member 28 described above. Accordingly, the X-ray emitted from the output shaft 27a of the spindle motor 27 passes through the through holes 16a, 17a, and 18a, and the measurement object is positioned below and outside via the circular hole 50c1 provided in the notch wall 50c. It is emitted toward OB. In this case, since the inner diameter of the passage member 28 and the inner diameter of the through hole 18a are small, the X-rays that have entered the through holes 27b, 27a1, 16a, and 17a through the passage member 28 are slightly diffused, but the through hole 18a. X-rays emitted from the light become parallel light parallel to the axis of the through hole 27a1 and are emitted from the circular hole 50c1. The inner diameter of the circular hole 50c1 is large in order to guide the diffracted light from the measurement object OB to the imaging plate 15.

  The imaging plate 15 is driven by the feed motor 22 and moves together with the moving stage 21, the spindle motor 27, and the table 16 from the origin position to the diffraction ring imaging position for imaging the diffraction ring. As described above, the measurement object OB is irradiated with the X-rays emitted from the X-ray emitter 10 at the diffraction ring imaging position. In addition, the imaging plate 15 is driven by the feed motor 22 while being driven by the spindle motor 27 and rotated, together with the moving stage 21, the spindle motor 27, and the table 16, in the diffraction ring reading region for reading the imaged diffraction ring, And move in the diffractive ring erasing region to erase the diffractive ring. In this case, in the movement of the imaging plate 15, the central axis of the imaging plate 15 is the optical axis of the X-ray emitted from the X-ray emitter 10 and the position (line) at a rotation angle of 0 ° in the imaging plate 15. In a state maintained in a plane formed by the X-ray, it moves in a direction perpendicular to the optical axis of the X-ray.

  The laser detection device 30 detects the intensity of light incident from the imaging plate 15 by irradiating the imaging plate 15 that images the diffraction ring with laser light. The laser detection device 30 is sufficiently separated from the measurement object OB and the imaging plate 15 at the diffraction ring imaging position toward the feed motor 22. That is, when the imaging plate 15 is at the diffraction ring imaging position, the X-ray diffracted by the measurement object OB is not blocked by the laser detection device 30. The laser detection device 30 includes a laser light source 31, a collimating lens 32, a reflecting mirror 33, a dichroic mirror 34, and an objective lens 36.

  The laser light source 31 is controlled by the laser driving circuit 77 to emit laser light that irradiates the imaging plate 15. The laser drive circuit 77 is controlled by the controller 91 and controls and supplies a drive signal so that laser light having a predetermined intensity is emitted from the laser light source 31. The laser drive circuit 77 inputs a light reception signal output from the photodetector 42 described later, and controls a drive signal output to the laser light source 31 so that the intensity of the light reception signal becomes a predetermined intensity. Thereby, the intensity of the laser light applied to the imaging plate 15 is kept constant.

  The collimating lens 32 converts the laser light emitted from the laser light source 31 into parallel light. The reflecting mirror 33 reflects the laser light converted into parallel light by the collimating lens 32 toward the dichroic mirror 34. The dichroic mirror 34 transmits most of the laser light incident from the reflecting mirror 33 (for example, 95%) as it is. The objective lens 36 focuses the laser light incident from the dichroic mirror 34 on the surface of the imaging plate 15. The optical axis of the laser light emitted from the objective lens 36 is in a plane formed by the optical axis of the X-ray emitted from the X-ray emitter 10 and the position (line) at the rotation angle 0 ° in the imaging plate 15. The direction parallel to the optical axis of the X-ray, that is, the direction perpendicular to the moving direction of the moving stage 21.

  A focus actuator 37 is assembled to the objective lens 36. The focus actuator 37 is an actuator that moves the objective lens 36 in the optical axis direction of the laser light. The objective lens 36 is located at the center of the movable range when the focus actuator 37 is not energized.

  When the laser beam condensed by the objective lens 36 is irradiated on the surface of the imaging plate 15 where the diffraction ring is imaged, a photo-stimulated luminescence phenomenon occurs. That is, after imaging the diffraction ring, when the imaging plate 15 is irradiated with laser light, the phosphor of the imaging plate 15 is light corresponding to the intensity of the diffracted X-ray and has a wavelength shorter than the wavelength of the laser light. To emit. The reflected light of the laser light irradiated and reflected on the imaging plate 15 and the light emitted from the phosphor pass through the objective lens 36, and most of the light emitted from the phosphor is reflected by the dichroic mirror 34. Most of the reflected light of the laser beam is transmitted. In the reflection direction of the dichroic mirror 34, a condenser lens 38, a cylindrical lens 39, and a photodetector 40 are provided. The condensing lens 38 condenses the light incident from the dichroic mirror 34 on the cylindrical lens 39. The cylindrical lens 39 causes astigmatism in the transmitted light. The photodetector 40 is composed of four divided light receiving elements composed of four light receiving elements having the same square shape divided by dividing lines, and the light incident on the light receiving areas A, B, C, and D arranged in the clockwise direction. A detection signal having a magnitude proportional to the intensity is output to the amplifier circuit 78 as a light reception signal (a, b, c, d).

  The amplifying circuit 78 amplifies the light reception signals (a, b, c, d) output from the photodetector 40 with the same amplification factor to generate light reception signals (a ′, b ′, c ′, d ′), Output to the focus error signal generation circuit 79 and the SUM signal generation circuit 80. In this embodiment, focus servo control based on the astigmatism method is used. The focus error signal generation circuit 79 generates a focus error signal by calculation using the amplified light reception signals (a ′, b ′, c ′, d ′). That is, the focus error signal generation circuit 79 calculates (a ′ + c ′) − (b ′ + d ′) and outputs the calculation result to the focus servo circuit 81 as a focus error signal. The focus error signal (a ′ + c ′) − (b ′ + d ′) represents the amount of deviation of the focal position of the laser beam from the surface of the imaging plate 15.

  The focus servo circuit 81 is controlled by the controller 91, generates a focus servo signal based on the focus error signal, and outputs the focus servo signal to the drive circuit 82. The drive circuit 82 drives the focus actuator 37 according to the focus servo signal to displace the objective lens 36 in the optical axis direction of the laser light. In this case, the focus servo signal is generated so that the value of the focus error signal (a ′ + c ′) − (b ′ + d ′) is always a constant value (for example, zero), so that the laser is applied to the surface of the imaging plate 15. The light can be continuously collected.

  The SUM signal generation circuit 80 adds the received light signals (a ′, b ′, c ′, d ′) to generate a SUM signal (a ′ + b ′ + c ′ + d ′) and outputs it to the A / D conversion circuit 83. To do. The intensity of the SUM signal is equivalent to the intensity of a small amount of laser light reflected by the imaging plate 15 and reflected by the dichroic mirror 34 and the intensity of light generated by the stimulated emission. Since the intensity of the reflected laser light is substantially constant, the intensity of the SUM signal corresponds to the intensity of light generated by the stimulated emission. That is, the intensity of the SUM signal corresponds to the intensity of the diffracted X-ray incident on the imaging plate 15. The A / D conversion circuit 83 is controlled by the controller 91, receives the SUM signal from the SUM signal generation circuit 80, converts the instantaneous value of the input SUM signal into digital data, and outputs the digital data to the controller 91.

  Further, the laser detection device 30 includes a condenser lens 41 and a photodetector 42. The condenser lens 41 is a part of the laser light emitted from the laser light source 31, and condenses the laser light reflected without passing through the dichroic mirror 34 on the light receiving surface of the photodetector 42. The photodetector 42 is a light receiving element that outputs a light receiving signal corresponding to the intensity of light collected on the light receiving surface. Therefore, the photodetector 42 outputs a light reception signal corresponding to the intensity of the laser light emitted from the laser light source 31 to the laser driving circuit 77.

  Further, an LED light source 43 is provided adjacent to the objective lens 36. The LED light source 43 is controlled by the LED drive circuit 84 to emit visible light and erase the diffraction ring imaged on the imaging plate 15. The LED drive circuit 84 is controlled by the controller 91 and supplies a drive signal for generating visible light having a predetermined intensity to the LED light source 43.

  The X-ray diffraction measurement apparatus has an LED light source 44. As shown in FIGS. 2 to 4, the LED light source 44 is fixed to the lower surface of one end portion of the plate 45 disposed between the X-ray emitter 10 and the upper wall 26 of the table driving mechanism 20. The plate 45 is fixed to the output shaft 46a of the motor 46 fixed in the housing 50 at the other end upper surface, and is in a plane parallel to the upper wall 26 of the table driving mechanism 20 by the rotation of the motor 46. Rotate. Stopper members 47 a and 47 b are provided on the upper wall 26 of the table driving mechanism 20. When the plate 45 is rotated in the direction D <b> 1 in FIG. 4, the LED light source 44 is connected to the X-ray emitter 10. The rotation of the plate 45 is restricted so that it stops at a position (position A) opposite to the exit hole 11 and the through hole 26 a of the upper wall 26 of the table drive mechanism 20. On the other hand, when the plate 45 is rotated in the direction D2 in FIG. 4, the stopper member 47b is formed between the emission port 11 of the X-ray emitter 10 and the through hole 26a of the upper wall 26 of the table driving mechanism 20. The rotation of the plate 45 is restricted so that it stops at a position (B position) that is not blocked. In other words, the A position is a position where the plate 45 is in the state shown in FIGS. 2 and 3, and the LED light emitted from the LED light source 44 enters the passage of the passage member 28 provided in the through hole 27 a 1 of the spindle motor 27. This is the incident position. The B position is a position where X-rays emitted from the X-ray emitter 10 are not blocked by the plate 45.

  The LED light source 44 emits LED light according to a drive signal from an LED drive circuit 85 that is controlled by the controller 91. LED light is diffused visible light, and when the plate 45 is in the A position, a part of the plate 45 passes through the through holes 26a and 21a, the passage of the passage member 28 and the through hole 27b, and the output shaft 27a of the spindle motor 27. Is incident on the through hole 27a1 and emitted from the through holes 16a, 17a, 18a and the circular hole 50c1 of the notch wall 50c. Also in the case of this LED light, since the inner diameter of the passage member 28 and the inner diameter of the through hole 18a are small, the X-rays that have entered the through holes 27b, 27a1, 16a, and 17a through the passage member 28 are slightly diffused. The LED light emitted from the through hole 18a becomes parallel light parallel to the axis of the through hole 27a1, and is emitted from the circular hole 50c1. Therefore, the LED light source 44, the passage member 28, the through hole 18a, and the like constitute the visible light emitter of the present invention that emits parallel light, which is visible light, to the measurement object OB.

  The motor 46 includes an encoder 46b similar to the encoders 22a and 27a. The encoder 46b generates a pulse train signal that alternately switches between a high level and a low level each time the motor 46 rotates by a predetermined minute rotation angle. 86. When a rotation direction and a rotation start instruction are input from the controller 91, the rotation control circuit 86 outputs a drive signal to the motor 46 to rotate the motor 46 in the specified direction. When the input of the pulse train signal from the encoder 46b is stopped, the output of the drive signal is stopped. Thereby, the plate 45 can be rotated to the A position and the B position, respectively.

  An imaging lens 48 is provided on the cutout wall 50 c of the housing 50, and an imager 49 is provided inside the housing 50. The image pickup device 49 is composed of a CCD light receiver or a CMOS light receiver in which a large number of image pickup devices are arranged in a matrix, and receives a light reception signal (image pickup signal) having a magnitude corresponding to the intensity of light received by each image pickup device. For each output to the sensor signal extraction circuit 87. The imaging lens 48 and the image pickup device 49 pick up an image of a region centered on the emission point of the LED light on the measurement object OB located at a position set with respect to the imaging plate 15. That is, the imaging lens 48 and the imager 49 function as a digital camera that images the measurement object OB. The position set with respect to the imaging plate 15 means that a vertical distance L from the X-ray and LED light emission point (irradiation point) to the imaging plate 15 on the measurement object OB is a predetermined distance. Is the position. In this case, the depth of field by the imaging lens 48 and the imaging device 49 is set in a range before and after the emission point. The sensor signal extraction circuit 87 outputs the intensity data of the light reception signal (imaging signal) from each imaging device of the imaging device 49 to the controller 91 together with the data indicating the position (that is, the pixel position) of each imaging device. Therefore, as shown in FIG. 5, the controller 91 outputs image data representing an image in the vicinity of the irradiation point P1 including the LED light irradiation point P1 on the measurement object OB, and displays an image on the display device 93 described later. Will be.

  Further, the optical axis of the imaging lens 48 is adjusted so as to be included in a plane including the optical axis of the X-ray emitted from the X-ray emitter 10 and a line having a rotation angle of 0 ° of the imaging plate 15. This plane is perpendicular to the surface of the stage 61 when the object setting device 60 has an inclination angle of 0. Further, the point where the optical axis of the imaging lens 48 and the optical axes of the X-rays and LED light irradiated to the measurement object OB intersect with each other in the X of the measurement object OB at a position set with respect to the imaging plate 15. It is the emission point (irradiation point) of the line and LED light. Further, an imaging lens is used with respect to the normal of the surface of the stage 61 when the inclination angle of the object setting device 60 passes through the X-ray and LED light emission points of the measurement object OB at the set position. The angle formed by the optical axis 48 is the angle formed by the X-ray emitted from the X-ray emitter 10 and the optical axis of the LED light emitted from the LED light source 44 with respect to the normal line (incidence of the X-ray and LED light). Angle).

  Therefore, the irradiation point of X-rays and LED light on the measurement object OB is at a position set with respect to the imaging plate 15, and the surface of the irradiation point is parallel to the upper surface of the stage 61 with an inclination angle of 0. When the measurement object OB is irradiated with the LED light from the LED light source 44, an image of the measurement object OB including the irradiation point P1 is captured by the imaging device 49, and the measurement object OB The light receiving point P2 of the reflected LED light is also imaged at the same position as the irradiation point P1 by the imager 49. That is, the LED light applied to the measurement object OB is parallel light, and the LED light generates scattered light and reflected light that is reflected substantially as parallel light at the irradiation point of the LED light on the measurement object OB. As shown in FIG. 5, the light incident on the imaging lens 48 among the scattered light forms an image at the position of the image pickup device 49 to become an image of the irradiation point P1, and the reflected light incident on the imaging lens 48 is condensed. The light is condensed by the image lens 48 and received by the image pickup device 49, and an image of the light receiving point P2 is obtained. At this time, if the irradiation point of the X-ray and the LED light is at the set position and the surface of the irradiation point is parallel to the upper surface of the stage 61 having the inclination angle 0, the light of the scattered light incident on the imaging lens 48 Since both the axis and the optical axis of the reflected light coincide with the optical axis of the imaging lens 48, the irradiation point P1 and the light receiving point P2 are at the same position. Note that the imaging device 49 images the measurement object OB, and the imaging device 49 is located slightly behind the focal position of the imaging lens 48. Strictly speaking, the reflection received by the imaging device 49 is reflected. The light is slightly diffused after being collected.

  The computer device 90 includes a controller 91, an input device 92, and a display device 93. The controller 91 is an electronic control unit mainly including a microcomputer including a CPU, ROM, RAM, a large capacity storage device, and the like, and executes various programs stored in the large capacity storage device to perform an X-ray diffraction measurement device. Control the operation of The input device 92 is connected to the controller 91 and is used by an operator to input various parameters, work instructions, and the like. As shown in FIG. 5, the display device 93 is in a position where irradiation points of X-rays and LED light are set on the display screen in addition to the image captured by the imager 49, and the surface of the irradiation point is inclined. When it is parallel to the upper surface of the stage 61 at the corner 0, a cross mark is displayed at a position where the irradiation point P1 and the light receiving point P2 are displayed. This cross mark is displayed independently of the captured image. Therefore, if the position and orientation of the stage 61 (measurement object OB) of the object setting device 60 are adjusted so that the irradiation point P1 and the light receiving point P2 coincide with the cross mark, the imaging plate 15 starts from the X-ray irradiation point. Is a predetermined distance, and the incident angle of the X-ray with respect to the measurement object OB is a predetermined angle (an angle formed by the optical axis of the X-ray and the normal line of the upper surface of the stage 61 having an inclination angle of 0). Further, the display device 93 visually notifies the operator of various setting situations, operating situations, measurement results, and the like. The high voltage power supply 95 supplies the X-ray emitter 10 with a high voltage and current for X-ray emission.

  When the measurement object OB has a complicated shape such as a gear, it may be necessary to irradiate the X-ray from a direction in which the diffracted X-ray is not obstructed. It is difficult to make the incident angle with respect to the object OB a predetermined angle. In such a case, the position and orientation may be adjusted so that only the irradiation point P1 coincides with the cross mark. It is possible to determine the surface hardness of the measurement object OB without setting the X-ray incident angle to a predetermined angle, and it is also possible to determine the residual stress by calculating the X-ray incident angle from the formed diffraction ring. It is. This will be described later.

  When measuring the surface hardness and residual stress of the measurement object OB using the X-ray diffraction measurement system including the X-ray diffraction measurement apparatus configured as described above, the process shown in FIG. 6 is performed. The operator first irradiates LED light from the X-ray diffraction measurement device in the stage adjustment step S1 to adjust the position and posture of the stage 61 (measurement object OB) of the object setting device 60. Next, in the diffraction ring imaging step S2, X-rays are irradiated to form a diffraction ring on the imaging plate 15. Next, in the diffraction ring reading step S3, the intensity distribution of the diffracted X-rays is measured by irradiating the laser beam from the laser detector 30 while rotating the table 16. Next, the diffraction ring formed on the imaging plate 15 in the diffraction ring elimination step S4 is erased. In the calculation step S5, the half-value width in the radial intensity distribution of the diffraction ring is calculated and averaged at a plurality of locations, and the average value of the half-value widths is obtained with the half-value width and the surface hardness obtained in advance. Fit the relationship curve to calculate the surface hardness. Further, the residual stress is calculated by detecting the shape of the diffraction ring from the intensity distribution of the diffracted X-rays.

  Hereinafter, steps S1 to S5 will be described. Steps S1 to S4 are described in detail in Japanese Patent Application Laid-Open No. 2014-98677, so only a brief description will be given. In the stage adjustment step S1, the operator places the measurement object OB on the stage 61 so that the measurement direction of the residual stress matches the Y-axis direction, and inputs the start of stage adjustment from the input device 92. As a result, the controller 91 outputs a command to each circuit, the imaging plate 15 is in the diffraction ring imaging position (the state of FIGS. 1 and 2), the plate 45 is in the A position, the LED light source 44 is lit and the LED is turned on. Light is emitted and applied to the measurement object OB. Further, an image pickup signal is input from the image pickup device 49 and a picked-up image is displayed on the display device 93. As shown in FIG. 5, since the LED light irradiation point P1 and the reflected light receiving point P2 are displayed in the captured image, the operator moves the stage 61 in the X-axis, Y-axis, and Z-axis directions while viewing the captured image. The irradiation point P1 is adjusted so that it coincides with the measurement location and the cross mark. Then, the stage 61 is rotated (tilted) around the X axis and the Y axis, and the light receiving point P2 is adjusted so as to coincide with the cross mark. As a result, the irradiation point P1 slightly deviates from the measurement position and the cross mark. By repeating a small amount of movement in the directions of the axis, Y axis, and Z axis and a minute rotation around the X axis and Y axis, the irradiation point P1 and the light receiving point P2 are made to coincide with the cross mark.

  Thereby, the X-ray irradiated to the measurement object OB becomes a measurement location, the Y-axis direction becomes the measurement direction of the residual stress, the distance L from the X-ray irradiation point to the imaging plate 15 becomes a predetermined distance, The incident angle of the X-ray with respect to the measurement object OB becomes a predetermined angle. As described above, when the measurement object OB has a complicated shape and it is difficult to set the incident angle of the X-ray to a predetermined angle, adjustment is performed so that only the irradiation point P1 matches the cross mark. Just do it.

  Next, the operator inputs the end of stage adjustment from the input device 92. Thereby, the controller 91 outputs a command to each circuit, stops the light emission of the LED light, stops the signal input from the image pickup device 49, and rotates the plate 45 to the B position. This completes the stage adjustment step S1.

  In the next diffraction ring imaging step S2, the operator inputs from the input device 92 the material of the measurement object OB (in this example, iron) and whether or not the X-ray incident angle ψ is a predetermined angle. As will be described later, when measurement is performed with the X-ray incident angle ψ set to 0 ° (normal incidence), the fact that the incidence is normal is input. Then, the start of measurement of surface hardness and residual stress is input. As a result, the controller 91 outputs a command to each circuit, rotates the imaging plate 15 at a low speed, sets the rotation angle to 0 °, which is an angle at which the index signal is input from the encoder 27c, and then outputs the X-ray from the X-ray emitter 10. The line is emitted and the emission is stopped after a predetermined time. Thereby, the diffraction ring is imaged on the imaging plate 15 by diffracted X-rays generated by X-rays having a predetermined intensity in a predetermined time.

  After the diffraction ring imaging step S2, the controller 91 automatically executes the diffraction ring reading step S3. The controller 91 outputs a command to each circuit, moves the imaging plate 15 to the diffraction ring reading start position, then rotates the table 16 at a predetermined constant rotational speed, and transmits laser light from the laser detection device 30 to the imaging plate 15. To irradiate. Then, focus servo control for focusing the laser beam on the surface of the imaging plate 15 is started, and movement of the imaging plate 15 in the lower right direction in FIGS. 1 and 2 is started. In this state, the operation of the rotation angle detection circuit 75, the position detection circuit 72, and the A / D converter 83 is started, and every time the rotation angle θp of the imaging plate 15 rotates by a predetermined small angle, the rotation angle θp and the laser Inputting and storing the radial distance r (radius value r) of the light irradiation position and the instantaneous value I (the intensity of the diffracted X-ray) of the signal from the A / D converter 83 is started. Thereby, the data of the rotation angle θp, the radius value r, and the instantaneous value I are stored for each irradiation position of the laser beam rotating in a spiral shape.

  In parallel with the storage operation, the controller 91 creates a change curve of the instantaneous value I with respect to the radius value r for each of a plurality of set rotation angles, and the change curves are obtained symmetrically at all rotation angles. At the time, the storage operation of the instantaneous value I, the rotation angle θp, and the radius value r is finished. Thereafter, the controller 91 outputs a command to each circuit to stop the focus servo control, stop the laser light irradiation, stop the movement of the imaging plate 15, and operate the rotation angle detection circuit 75 and the A / D converter 83. Stop. Thereby, the diffraction ring reading step S3 is completed. At this time, the intensity distribution of the diffracted X-rays in the diffraction ring is obtained as data of the rotation angle θp, the radius value r, and the instantaneous value I.

  After the diffraction ring reading step S3, the controller 91 automatically executes a diffraction ring elimination step S4. The controller 91 outputs a command to each circuit, moves the imaging plate 15 to the diffraction ring erasing start position, emits LED light from the LED light source 43, and irradiates the imaging plate 15 with the imaging plate 15 in FIG. And it is moved at a constant speed in the lower right direction of FIG. The rotation of the imaging plate 15 and the operation of the position detection circuit 72 are continued from the diffraction ring reading step S3. As a result, visible light from the LED light source 43 is spirally irradiated onto the imaging plate 15, and the diffraction ring formed by the diffracted X-rays is erased. When the diffraction ring erasure end position is reached, the controller 91 outputs a command to each circuit to stop the movement of the imaging plate 15, stop the light emission of the LED light source 43, stop the rotation of the imaging plate 15, and stop the operation of the position detection circuit 72. Do. Thereby, the diffraction ring erasing step S4 ends.

  After such a diffraction ring elimination step S4, the controller 91 performs the calculation step S5 automatically or in response to a command from the input device 92 by the operator. This calculation step S5 may be performed in parallel with the diffraction ring elimination step S4. In the calculation step S5, the controller 91 executes the installed calculation program, and uses the rotation angle θp, the radius value r, and the instantaneous value I data, and the pre-stored relationship curve between the half width and the surface hardness. The surface hardness of the measurement object OB is calculated. Using the rotation angle θp, the radius value r, and the instantaneous value I data and the previously stored parameters such as the distance L from the X-ray irradiation point to the imaging plate 15, the X-ray incident angle ψ, and the lattice plane spacing. Calculate the residual stress.

First, the surface hardness calculation method will be described. The controller 91 calculates in the order of (1) to (7) shown below, and calculates the surface hardness. (1) Creation of an intensity distribution curve of diffracted X-rays in the radial direction of the diffraction ring. A change curve of the instantaneous value I with respect to the radius value r (hereinafter referred to as r-I change curve) is created as shown in FIG. This is an intensity distribution curve of diffracted X-rays in the radial direction of the diffraction ring. In the data processing, the data group of the radius value r and the instantaneous value I is collected in the numerical order of the radius value r for each rotation angle θp. When the half-value width is a unit of angle in the stored relationship between the half-value width and the surface hardness, the radius value r is calculated by calculating tan ⁻¹ (radius value r / distance L). In units.

(2) Extraction of normal intensity distribution curve Ideally, the relationship curve should be symmetrical and pointed, but the measurement object OB has large crystal grains and the measurement object OB has a complicated shape. For this reason, there is a portion where the shape of the rI change curve is bad because, for example, a part of the diffracted X-ray is cut off. Next, processing for removing the rI change curve having a bad shape is performed. Specifically, the skewness and kurtosis of the r-I change curve are calculated, and the case where the skewness is larger than the pre-stored allowable value and the case where the kurtosis is smaller than the pre-stored allowable value are excluded. Perform the process. The skewness and kurtosis may be calculated using the normal skewness and kurtosis calculation formulas used in statistics with the peak value of the rI change curve as the average value. The skewness is a value for evaluating the left-right symmetry of the change curve, and the kurtosis is a value for evaluating the degree of sharpness of the change curve. As a result, an r-I change curve having a normal shape is extracted. If the number of r-I change curves extracted at this time is less than a preset allowable value, the half-value width averaging process described later cannot be performed with high accuracy, so that the display device 93 has a surface. When the hardness cannot be measured, an instruction to perform measurement by causing X-rays to enter the measurement object OB perpendicularly (at an incident angle of 0 °) is displayed, and the calculation of the surface hardness is completed. The reason will be described later. Further, a method for causing X-rays to enter the measurement object OB perpendicularly will be described later.

(3) Half width calculation Next, in all the extracted r-I change curves, the level obtained by dividing the difference between the peak value of the r-I change curve and the ground level value by 2, and adding the ground level value to that value The width of the change curve when the change curve is sliced is obtained as the half-value width W. This is the width indicated by W in FIG.

(4) Creating a change curve of the half width with respect to the circumferential position (rotation angle) If the average of the obtained half width W is applied to the relationship curve between the half width and the surface hardness, the measurement object The surface hardness of OB can be obtained. However, when a diffraction ring is created by causing X-rays to enter the measurement object OB at a predetermined incident angle as in the present embodiment, unless there is anything excluded by the r-I change curve, that is, all Unless the full width at half maximum W is obtained at the rotation angle θp, it is not possible to obtain an accurate average value by normal average calculation. The reason is that the change curve of the half-value width W with respect to the circumferential position (rotation angle) θp is always a sine curve having a rotation angle of 0 ° as a peak point and excluded by the r-I change curve. This is because a part of the change curve is missing, and therefore, in the normal average calculation, the average value deviates from the value of the center line (original average value) of the change curve. Therefore, a change curve of the half width W with respect to the circumferential position (rotation angle) θp (hereinafter referred to as θp-W change curve) is created, and an average value of the half width W is calculated from the θp-W change curve. . The creation of the θp-W change curve is a process for obtaining data of the half width W ′ obtained by performing the smoothing process using the data group of the rotation angle θp and the half width W in terms of data processing.

  When the number of r-I change curves extracted in the process (2) is less than the allowable value, the calculation process is terminated because the average value is accurately obtained when there are too many missing portions in the θp-W change curve. It is because it cannot ask. At this time, X-rays are incident on the measurement object OB at an incident angle of 0 ° so as to be displayed on the display device 93, and measurement is performed. When X-rays are incident on the measurement object OB at an incident angle of 0 °, the θp-W change curve becomes a straight line. Therefore, after performing the processing up to (3), the data value is added and divided by the number of data. The half width W can be averaged by a normal average calculation.

  When the inventor of the present application measures a large number of measurement objects OB a plurality of times and sets the incident angle of X-rays to the measurement object OB to 0 °, the θp-W change curve becomes a straight line, and the incident angle is set to 0 °. From this, it was found that the θp-W change curve is a sine curve having a rotation angle of 0 ° as a peak point, and its amplitude value increases. This is shown in FIG. It was also found that when the incident angle of X-rays is changed, the amplitude value changes, but the average value, that is, the value of the center line of the θp-W change curve does not change. They also found that these could be explained theoretically. Therefore, even if the incident angle of X-rays is 0 ° or a value other than the set value, the average value of the half width W does not change, and the surface hardness calculated from the half width W does not change. Therefore, as described above, when there are many missing portions in the θp-W change curve, the X-ray incident angle can be set to 0 ° and the measurement can be performed again, and the measurement object OB has a complicated shape. In this case, measurement can be performed without setting the incident angle of X-rays to a predetermined angle. Since it is important that the above characteristic of the θp-W change curve can be theoretically explained, it will be described in detail later.

(5) Exclusion of abnormal part of half-width change curve The created θp-W 'change curve is a sine curve if it is normal, but an abnormal r-I change curve remains even after the processing of (2). There is a possibility that there is a part deviating from the sine curve due to the reason. Therefore, a process of excluding abnormal portions from the θp-W ′ change curve is performed. In this process, first, the peak value and bottom value portions of the θp-W ′ change curve are detected, and after confirming that the rotation angle θp is different by 180 °, from the data of all the half widths W ′. Subtract the median value between the peak value and the bottom value, and create the half width W "divided by the difference between the peak value and the median value (difference between the median value and the bottom value). This is a standardized curve (bottom A curve with a value of -1 and a peak value of 1.) At this time, if any one of the peak value and the bottom value is not obtained as a result of the processing of (2), the peak The value obtained by averaging the data of the two half-value widths W ′ at the position 90 degrees from the value or the bottom value is set to the intermediate value, and the same processing is performed, and neither the peak value nor the bottom value is obtained. In this case, the number of r-I change curves extracted in the process (2) is smaller than the allowable value. Similar to time, the non-measurable and X-ray of the surface hardness is incident at an incident angle of 0 ° to the measurement object OB on the display device 93 displays an indication to perform measurement, calculation of surface hardness is terminated.

  After the half-value width W ″ is created, the θp−W ″ change curve is compared with the sin (θp + 90 ° + α) curve, and a process of excluding a portion having a large deviation from sin (θp + 90 ° + α) is performed. In data processing, α of sin (θp + 90 ° + α) is changed little by little, and the square of the difference between each half-value width W ″ and the value of sin (θp + 90 ° + α) is added and divided by the number of data Α is obtained as αd when the obtained value is minimum. Next, the half value width corresponding to the half value width W ″ whose absolute value of the difference between the half value width W ″ and the value of sin (θp + 90 ° + αd) is larger than the allowable value. The price range W ′ is excluded from the θp−W ′ change curve, whereby the abnormal portion is excluded from the θp−W ′ change curve.

  Here, the reason for obtaining the minimum value αd of α will be described. In the θp-W "change curve, a line XI where the plane including the optical axis of the emitted X-ray and the normal of the surface of the X-ray irradiation point intersects the imaging plate 15 is a line with a rotation angle of 0 °. However, since the measurement object OB has a complicated shape in the stage adjustment step S1, only the irradiation point P1 is adjusted so as to match the cross mark, and the curve becomes sin (θp + 90 °). If the light receiving point P2 is not adjusted, the line XI may deviate from the line having the rotation angle of 0 °. In this case, the peak point and the bottom point of the θp-W ″ change curve have the rotation angle θp. The point is shifted from the 0 ° point. Accordingly, sin (θp + 90 ° + α) is set, and processing for obtaining the minimum value αd of α is performed. Αd is an angle of deviation between the line XI and a line having a rotation angle of 0 °.

(6) Average value calculation of half-value width Next, the average value of the half-value width W is calculated from the θp−W ′ change curve. The calculation method of this process differs depending on the total number of rI change curves and the number of half-value widths W ′ excluded in the process (2) and the process (5). First, when none is excluded, a normal average calculation is performed in which all the half-value widths W are added and divided by the number of data. This is a calculation in which the θp−W ′ change curve is integrated and divided by the horizontal axis size of 360 °. Next, if the number of exclusions is less than the allowable value, the data W ′ lacking the θp−W ′ change curve is created by interpolation using the data on both sides, and the data is obtained by adding all the half-value widths W ′. Calculate by dividing by a number. This is a calculation in which a portion lacking the θp−W ′ change curve is created and integrated and divided by the size of 360 ° on the horizontal axis. Next, when the number of exclusions is larger than the allowable value, calculation is performed to obtain A and B of the curve [A · sin (θp + 90 ° + αd) + B] that most closely matches the θp−W ′ change curve. This calculation is performed as follows. When the θp−W ′ change curve has a peak point and a bottom point, first, (peak value−bottom value) / 2 is set to A, and (peak value + bottom value) / 2 is set to B. Next, every time A is changed by a minute amount, B is changed in a predetermined range, and the half value width W ′, the value of [A · sin (θp + 90 ° + αd) + B], and the square of the difference are added to obtain the number of data. A and B when the value divided by is minimized. If the θp-W ′ change curve has only one of a peak point and a bottom point, a value C is calculated by averaging two half-value widths W ′ at a position where the rotation angle θp is 90 ° from the peak value or the bottom value. (Peak value-C) or (C-bottom value) is set to A, and C is set to B. Similarly, each time A is changed by a small amount, B is changed within a predetermined range, and the half-value width W ′, the value of [A · sin (θp + 90 ° + αd) + B], and the square of the difference are added. Then, A and B when the value divided by the number of data is minimum are obtained. B obtained as a result of the calculation is an average value of the half width W. This is because B is obtained by integrating the curve of [A · sin (θp + 90 ° + αd) + B] and dividing it by 360 ° of the horizontal axis. Note that A is a value not related to the average value of the half width W, but as described above, the amplitude value of the θp-W change curve increases as the X-ray incident angle increases. As will be described later, it can be used when calculating the incident angle of the X-ray with respect to the measurement object OB.

(7) Calculation of surface hardness of measurement object OB Next, the average value of the half-value width W is applied to a relationship curve between the half-value width and the surface hardness stored in advance to determine the surface hardness of the measurement object OB. calculate. The relationship curve between the half width and the surface hardness is as shown in FIG. 9, and this relationship curve is prepared by preparing a sample with the surface hardness changed and measuring the above-mentioned using the above-described X-ray diffraction measurement system. The average value of the half width W can be obtained by the method and the calculation method, and the surface hardness of the sample can be measured by a destructive inspection method which is a known technique. The fact that there is a correlation between the half-value width and the surface hardness is also described in the prior art documents, but if the diffraction ring is imaged and the average value of the half-value width is obtained as in the present invention, the correlation coefficient A correlation between a high half width and surface hardness can be obtained.

  Next, the controller 91 calculates the residual stress of the measurement object OB. In this calculation, after calculating the radius value rp at the peak point of the r-I change curve calculated in (2) of the surface hardness calculation of the measurement object OB, the diffraction ring represented by the rotation angle θp and the radius value rp. And a parameter L such as a distance L from the X-ray irradiation point to the imaging plate 15, an X-ray incident angle ψ, and a lattice plane spacing. This calculation method is a well-known technique and is described in detail in [0026] to [0044] of Japanese Patent Laid-Open No. 2005-241308 and [0007] to [0017] of Japanese Patent Laid-Open No. 2011-27550. I will omit it. In addition, since there is a portion where the radius value rp at the peak point cannot be obtained because the r-I change curve is not normal, and the shape of the entire diffraction ring cannot be obtained, it is necessary to calculate the residual stress by another method. Since this method is described in detail in Japanese Patent No. 5408234, it is omitted here.

  In the above-described stage adjustment step S1, since the measurement object OB has a complicated shape, the adjustment is made so that only the irradiation point P1 matches the cross mark, and the light receiving point P2 is not adjusted. There is an arithmetic processing performed before the calculation of the residual stress. This is because the X-ray incident angle ψ is not a set value, and the plane XI intersects the imaging plate 15 with a plane including the optical axis of the emitted X-ray and the normal of the surface of the X-ray irradiation point portion. Is a calculation process performed because it does not coincide with a line with a rotation angle of 0 °, and specifically, a process for obtaining an X-ray incident angle ψ and a process for correcting the data of the rotation angle θp. This will be described below.

  As described above, as the incident angle ψ of X-rays increases, the amplitude value of the θp-W change curve that is a sine curve increases. Therefore, if a relationship curve between the amplitude value of the θp-W ′ change curve obtained by smoothing the θp-W change curve and the X-ray incident angle ψ is obtained and stored in advance, the surface hardness of the measurement object OB is calculated. By applying the value A of the curve [A · sin (θp + 90 ° + αd) + B] calculated in (6) to the relationship curve, the X-ray incident angle ψ can be obtained. When the number excluded in (6) of the surface hardness calculation of the measurement object OB is less than the allowable value, the value of A in the curve of [A · sin (θp + 90 ° + αd) + B] by the method described above at this stage. Is calculated. The relationship curve between the amplitude value of the θp-W ′ change curve and the incident angle ψ of the X-ray has been described above using the above-described X-ray diffraction measurement system by preparing a measurement object OB whose surface is parallel to the stage 61. The value of A of the curve of [A · sin (θp + 90 ° + αd) + B] is obtained by the measurement method and the calculation method, and thereafter the X-ray incident angle ψ by rotating the operation element 65a of the object setting device 60 The value A of the curve of [A · sin (θp + 90 ° + αd) + B] may be obtained by the same method each time. The first X-ray incident angle ψ is a set value, and the second and subsequent X-ray incident angles ψ are obtained by subtracting the rotation angle indicated by the first operation element 65a from the rotation angle indicated by the operation element 65a after the rotation operation. The angle is obtained by adding the angle to the set value of the incident angle ψ.

  The correction of the rotation angle θp data is a correction in which the line XI where the plane including the optical axis of the emitted X-ray and the normal of the surface of the X-ray irradiation point intersects the imaging plate 15 is set to 0 °. is there. Specifically, the correction is performed by subtracting αd, which is the deviation angle between the line XI calculated in (6) of the surface hardness calculation of the measurement object OB and the line having the rotation angle of 0 °, from each rotation angle θp. is there.

  When the calculation of the surface hardness and residual stress of the measurement object OB is completed, the controller 91 displays the calculation result of the surface hardness and residual stress on the display device 93. In addition to this, the intensity distribution image of the diffraction ring (image obtained from the data group of the instantaneous value I, the rotation angle θp and the radius value r with the instantaneous value I as the brightness), the X-ray incident angle ψ, and the X-ray irradiation point Measurement conditions such as the distance L from the imaging plate 15 to the imaging plate 15 may be displayed. By looking at the result, the operator evaluates the surface hardness of the measurement object OB from the surface hardness value, and evaluates the fatigue level of the measurement object OB from the residual stress value.

  Here, when the display device 93 displays that the surface hardness cannot be measured and an instruction to perform measurement by causing X-rays to enter the measurement object OB perpendicularly (at an incident angle of 0 °), the X-rays are measured. A method of making the light incident on the OB perpendicularly will be described. In the stage adjustment step S1, when the irradiation point P1 and the light receiving point P2 are adjusted so as to coincide with the cross mark, the incident angle of the X-ray with respect to the measurement object OB is a set value. Therefore, in this case, the operation element 65a of the object setting device 60 is rotated, and an angle obtained by subtracting the rotation angle indicated by the operation element 65a before the rotation operation from the rotation angle indicated by the operation element 65a after the rotation operation is obtained. The tilt state of the stage 61 may be adjusted so that the set value of the incident angle is a minus value. Further, since the measurement object OB has a complicated shape, only the irradiation point P1 is adjusted so as to coincide with the cross mark, and when the light receiving point P2 is not adjusted, the measurement object OB is provided on the notch wall 50c. A black film is provided in parallel with the cutout wall 50c at the circular hole 50c1. Then, the irradiation point of the emitted light from the LED light source 44, which is the irradiation point of the two LED lights formed on the black film, and the irradiation point of the reflected light from the measurement object OB are matched. The operation element 65a and the operation element 66a of the object setting device 60 may be rotated.

Next, it will be theoretically explained that the θp-W change curve, which is the change curve of the half width W with respect to the circumferential direction of the diffraction ring as described above, has the following characteristics.
A sinusoidal curve having a peak point at a rotation angle of 0 ° (a portion of a line where a plane including the normal of the optical axis of the X-ray and the plane of measurement intersects the imaging plate).
As the X-ray incident angle increases, the amplitude value increases. When the X-ray incident angle is 0 °, the amplitude value is 0, that is, a straight line.
When the incident angle of X-rays is changed, the amplitude value increases, but the average value (the value of the center line of the θp-W change curve) does not change.

  The X-ray incident on the measurement object OB has a certain cross-sectional diameter, and the X-ray irradiation point has a certain area. Therefore, hereinafter, in this description, the X-ray irradiation point is referred to as an X-ray irradiation circle. FIG. 10 shows X-ray diffraction in the measurement object OB with the cross-sectional diameter of the incident X-ray exaggerated. When diffraction X-rays are generated from each point in the X-ray irradiation circle, The half width at the angle θp is the diffracted X-ray generated from two points where the plane including the optical axis of the incident X-ray and the line of the rotation angle θp of the imaging plate 15 intersects the outer periphery in the X-ray irradiation circle. It can be considered that it is proportional to the width when incident on the imaging plate 15 (hereinafter referred to as imaging width). As shown in FIG. 10A, the imaging width is widened at a rotation angle of 0 °, but the imaging width is narrowed at a rotation angle of 180 °. As shown in FIGS. 10A to 10C, the difference in the imaging width of the diffracted X-rays at the rotation angle of 0 ° and the rotation angle of 180 ° decreases as the X-ray incident angle decreases. Thereby, the amplitude value of the θp-W change curve increases as the rotation angle of 0 ° becomes the peak point and the incident angle of the X-ray increases, and the amplitude value becomes 0 when the incident angle is 0 °. Explain that it becomes a straight line. However, this explanation alone cannot explain that the θp-W change curve becomes a sine curve and that the average value (center line value) does not change depending on the incident angle of X-rays. Do.

  FIG. 11 is an enlarged view of the X-ray irradiation circle incident at the incident angle on the measurement object OB. As described above and as shown in FIG. 13, the half value at the rotation angle θp is as follows. The width W is such that diffracted X-rays generated from two points where a plane including the optical axis of incident X-rays and the line of the rotation angle θp of the imaging plate 15 intersects the outer circumference of the X-ray irradiation circle are applied to the imaging plate 15. It can be considered that it is proportional to the imaging width Wi at the time of incidence. Here, the diffracted X-rays are only diffracted X-rays having a predetermined angle with the optical axis of the X-rays. That is, it is assumed that the diffracted X-ray is a straight line along the side surface of the cone when the vertex is the generation point of the diffracted X-ray. The incident angle of the diffracted X-ray with respect to the imaging plate 15 is constant regardless of the rotation angle θp so that the angle formed by the straight line along the side surface of the cone and the bottom surface of the cone is constant everywhere. Therefore, as shown in FIG. 13, the imaging width Wi is obtained by multiplying the width Wd of diffracted X-rays generated from two points on the outer periphery of the X-ray irradiation circle by a constant. In addition, the width Wd of the diffracted X-rays generated from two points on the outer periphery of the X-ray irradiation circle includes the diffracted X-rays generated from the center of the X-ray irradiation circle and the diffracted X-rays generated from the outer peripheral point of the X-ray irradiation circle. The width Wr is doubled. Therefore, it can be considered that the half width W is proportional to the width Wr of the diffracted X-ray, and the θp-W change curve can be considered to have the same curve shape as the change curve of the width Wr of the diffracted X-ray with respect to the rotation angle θp. it can.

Next, consider an equation that holds in the distance Xcr from the center of the X-ray irradiation circle to the outer peripheral point of the X-ray irradiation circle at the rotation angle θp. When X-rays having a circular cross section are incident at a certain incident angle, the X-ray irradiation circle becomes an ellipse, and the equation of the distance from the center to the outer periphery of the ellipse is established. That is, as shown in FIG. 11, when the short axis radius of the ellipse is a and the long axis radius is b, the following equation 1 is established.
When viewed in the plane of the X-ray irradiation circle, the outer peripheral point of the X-ray irradiation circle does not coincide with the line of the rotation angle θp, but this is because the plane of the X-ray irradiation circle and the plane of the imaging plate 15 are equal to the X-ray incident angle. FIG. 11 shows two points where a plane including the optical axis of the incident X-ray and the line of the rotation angle θp of the imaging plate 15 intersects the outer periphery of the X-ray irradiation circle. Become a point. In the following description, in order to make the calculation formulas easier to understand, the directions of the X axis and the Y axis are the same as those in FIG. 2, but the rotation angle θp is 0 ° in the X axis direction and the value increases counterclockwise. Then. That is, the X-axis direction is the downward direction in FIG. 11, the Y-axis direction is the rightward direction in FIG. 11, and the rotation angle θp is 0 ° in the downward direction in FIG. Therefore, the rotation angle θp in the following description is a value obtained by subtracting 90 ° from the rotation angle θp in the description of the half width W by the X-ray diffraction system described above.

Assuming that the incident angle of X-rays is ψ, as shown in FIG. 12, the minor axis radius a of the ellipse is equal to the cross-sectional diameter Xr of the irradiated X-rays, and the major axis radius b is Xr / cos ψ. Therefore, Equation 1 can be rewritten as the following Equation 2.

Next, consider the width Wr of the diffracted X-ray at the rotation angle θp. As shown in FIG. 13, in a plane including the optical axis of the incident X-ray and the line of the rotation angle θp of the imaging plate 15, the angle formed by the diffracted X-ray and the plane of the X-ray irradiation circle is θk (hereinafter, diffracted X-ray). , The width Wr of the diffracted X-ray is Xcr · sin θk. Substituting the equation of Equation 2 into Xcr, the width Wr of the diffracted X-ray is expressed by Equation 3 below.
The angle θk formed by the diffracted X-ray with the plane varies depending on the rotation angle θp. If the angle between the optical axis of the incident X-ray and the diffracted X-ray is θr, the angle θk formed by the diffracted X-ray with the plane is 90 ° − (ψ + θr) when the rotation angle θp is 90 °. When θp is 270 °, it becomes 90 ° − (ψ−θr). When the rotation angle θp is between 90 ° and 270 °, the angle θk formed by the diffracted X-ray with the plane is an intermediate value between these two values.

  Next, an equation for obtaining the angle θk formed by the diffracted X-ray and the plane will be considered. First, as shown in FIG. 14, considering the case where the irradiated X-rays are irradiated perpendicularly to the plane of the measurement object, the center coordinates of the X-ray irradiation circle are set to (0, 0, 0), and the incident X-rays And (0, 0, L) are the coordinates of the point where the optical axis of and the plane of the imaging plate 15 intersect. Since the angle θr formed between the optical axis of the incident X-ray and the diffracted X-ray is constant, the angle θr is generated from the center of the X-ray irradiation circle on the plane including the optical axis of the incident X-ray and the line of the rotation angle θp of the imaging plate 15. The distance to the point where the diffracted X-ray intersects the imaging plate 15 is L · tan θr. Therefore, on the plane including the optical axis of the incident X-ray and the line of the rotation angle θp of the imaging plate 15, the coordinates of the point where the diffracted X-ray generated from the center of the X-ray irradiation circle intersects the imaging plate 15 is (L · tan θr · cos θp, L · tan θr · sin θp, L).

Next, from this state, as shown in FIG. 15, a state where the incident X-ray is inclined by an angle of ψ (a state where the X-ray incident angle is set to ψ) is considered. This can be considered as a state in which the coordinate group is rotated counterclockwise in the X-axis direction with the X axis as the rotation axis. Therefore, the coordinates before rotation (x, y, z) and the coordinates after rotation (x The following equation (4) holds for ', y', z ').
When the coordinates (0, 0, 0), (0, 0, L) and (L · tan θr · cos θp, L · tan θr · sin θp, L) are substituted into (x, y, z), the corresponding (x The coordinates of ', y', z ') are (0, 0, 0), (0, L · sinψ, L · cosψ) and (L · tanθr · cosθp, L · tanθr · cosψ · sinθp + L · sinψ, − L · tan θr · sin ψ · sin θp + L · cos ψ). Let these coordinates be coordinates O, coordinates Ic, and coordinates R.

Next, consider a vector S obtained by outer product of a vector V from the coordinate O to the coordinate Ic and a vector D from the coordinate O to the coordinate R. This vector S is a normal vector of a plane including the optical axis of the incident X-ray and the line of the rotation angle θp of the imaging plate 15. Next, a vector F obtained by outer product of the vector S and a unit vector of (0, 0, 1) is obtained. This vector F is a vector parallel to a line in which a plane including the optical axis of the incident X-ray and the line having the rotation angle θp of the imaging plate 15 intersects the plane of the X-ray irradiation circle (XY plane in FIG. 15). As shown in FIG. 15, the angle θk formed by the diffracted X-ray at the position of the rotation angle θp and the plane is an angle formed by the vector F and the vector D, and the magnitudes of the vector F and the vector D are | F | and | D If |, it can be obtained by the following inner product equation of vectors.
When the components of the vector F and the vector D are obtained by calculating the coordinate values of the coordinates O, the coordinates Ic, and the coordinates R and the outer product, substituting them into the equation 5, and rearranging the equations, the following equation 6 is established.

As a result, an equation for obtaining the angle θk formed by the diffracted X-rays and the plane is obtained. By substituting Equation 6 into θk in Equation 3, the following Equation 7 can be obtained.
In Equation 7, the variables are the rotation angle θp and the width Wr of the diffracted X-ray. If the incident angle ψ of the X-ray is set, the rest are constants. Therefore, the change curve of the width Wr of the diffracted X-ray with respect to the rotation angle θp is a sinusoidal curve having an amplitude value A of the following formula 8 and a centerline value (average value) B of the following formula 9.

  In Equation 8, the X-ray incident angle ψ changes in the amplitude value A, and the other values are constants. Therefore, it can be seen from Equation 8 that the amplitude value A of the sine curve increases as the incident angle ψ of X-rays increases, and the amplitude value A becomes 0 when the incident angle ψ of X-rays is 0 °. Also, in Equation 9, all are constants. Therefore, it can be seen from Equation 9 that the value (average value) B of the center line of the sine curve does not change regardless of the incident angle ψ of the X-ray. As described above, the θp-W change curve can be regarded as having the same shape as the change curve of the width Xr of the diffraction X-ray with respect to the rotation angle θp. I can say that. Thereby, the feature of the θp-W change curve could be theoretically explained.

  As can be understood from the above description, in the above-described embodiment, X-rays are emitted toward the measurement object OB, and the diffracted X-rays generated at the measurement object OB are compared with the optical axis of the emission X-ray. When the surface hardness of the measurement object OB is evaluated using an X-ray diffraction system that receives light at an imaging plate 15 having a vertically intersecting imaging surface and forms a diffraction ring on the imaging plate 15, diffraction is performed on the imaging plate 15. After forming a ring and detecting the intensity distribution of the diffracted X-rays in the formed diffractive ring, the calculation program executed by the controller 91 of the X-ray diffraction system uses the intensity distribution of the diffracted X-rays in the radial direction of the diffractive ring. The half width W is calculated and averaged at a plurality of locations of the diffraction ring, and measured using the average value of the obtained half width W and a relationship curve between the half width and surface hardness stored in advance. versus And it calculates the surface hardness of the object OB.

  According to this, even if there is a location where the intensity distribution of diffracted X-rays in the radial direction of the diffractive ring is not normal, a portion where the intensity distribution of diffracted X-ray is normal can be extracted to calculate the width of the diffracted ring. Therefore, the surface hardness of the measurement object OB with high accuracy can be obtained. In addition, since the diffraction ring width is calculated and averaged at a plurality of locations, variations in the diffraction ring width can be reduced, and the surface hardness of the measurement object OB can be accurately obtained by forming an X-ray diffraction image once. Can be requested.

  In the above embodiment, the calculation program executed by the controller 91 is θp, which is a change curve with respect to the circumferential direction of the diffraction ring having the half width W based on the detected intensity distribution of the diffracted X-rays in the diffraction ring. A −W change curve is calculated, and an average value of the half width W is calculated from the calculated θp−W change curve.

  According to this, since the half-value width W is calculated and averaged everywhere over the entire circumference of the diffraction ring, the variation in the half-value width W can be further reduced, and the measurement object is accurate. The surface hardness of the object OB can be obtained. Further, as described above, the amplitude of the θp-W change curve varies depending on the incident angle ψ of the X-ray to the measurement object OB, but the center line of the θp-W change curve, that is, the average value of the half width W. Therefore, the surface hardness of the measurement object OB can be obtained with high accuracy without making the incident angle of X-rays constant.

  In the above embodiment, the calculation program executed by the controller 91 calculates the centerline value of the sine curve when the sine curve most closely matches the calculated θp-W change curve, and calculates the calculated centerline value. The average value of the half width W is set.

  According to this, even when the diffracted X-ray is interrupted due to the measurement object OB having a complicated shape or the like, and even when a part of the diffraction ring is missing, the calculated θp-W change curve is the most. If the center line value of the coincident sine curve is obtained, the average value of the half width W can be obtained with high accuracy, and the surface hardness of the measurement object OB can be obtained with high accuracy.

  In the above embodiment, the arithmetic program executed by the controller 91 calculates the θp-W change curve, then normalizes the calculated θp-W change curve, and normalizes the sine curve of the normalized θp-W change curve. Deviations from are calculated, and locations where the calculated deviation exceeds a preset allowable value are excluded from the θp-W change curve.

  According to this, even if there is an abnormal part in the θp-W change curve, the average value of the half width W is obtained from the center line value of the most coincident sine curve after automatically removing the part. Therefore, the average value of the half width W can be accurately obtained in a short time, and the surface hardness of the measurement object OB can be accurately obtained.

  In the above embodiment, the calculation program executed by the controller 91 detects the shape of the diffraction ring based on the detected intensity distribution of the diffracted X-rays in the diffraction ring, and the cos α method is detected from the detected shape of the diffraction ring. Is used to calculate the residual stress of the measurement object OB. According to this, an object can be evaluated not only by surface hardness but also by residual stress.

  Furthermore, in carrying out the present invention, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the object of the present invention.

  In the above embodiment, the incident angle ψ of the X-ray with respect to the measurement object OB is set to a predetermined angle so that the residual stress of the measurement object OB can be measured in addition to the surface hardness of the measurement object OB. . When the normal portion of the θp-W change curve is small, the X-ray incident angle ψ with respect to the measurement object OB is set to 0 ° for measurement. However, when it is desired to measure only the surface hardness of the measurement object OB, the X-ray incident angle ψ with respect to the measurement object OB may be set to 0 ° from the beginning. In this case, since the θp-W change curve is a straight line, a half-value width can be obtained by extracting a portion where the r-I change curve is normal and performing a normal average calculation. In this case, the operator may display an r-I change curve on the display device 93 and extract a portion determined to be appropriate. Further, when the X-ray diffraction measurement apparatus is used only for measuring the surface hardness of the measurement object OB, the housing 50 of the X-ray diffraction measurement apparatus is supported in a posture in which X-rays are incident on the stage 61 perpendicularly. You may make it fix to the rod 52. FIG.

  In the above embodiment, the X-ray incident angle ψ with respect to the measurement object OB is adjusted to a predetermined angle, and the adjustment is difficult when the measurement object OB has a complicated shape or the like. In the calculation of the residual stress, the X-ray incident angle ψ is obtained from the amplitude value of the θp-W change curve. However, if the accuracy of the residual stress calculation may be slightly reduced, the measurement object OB The X-ray incident angle ψ may not be adjusted. According to this, the time required for adjustment can be shortened without changing the measurement accuracy of the surface hardness of the measurement object OB.

  In the above embodiment, after the diffraction ring is formed on the imaging plate 15 and the intensity distribution of the diffracted X-ray is detected, the surface hardness and residual stress of the measurement object OB are calculated by executing the calculation program of the controller 91. I tried to do it. However, if the measurement may take time, the calculation using the intensity distribution data of the diffracted X-rays may be performed by another device, or a part or all of the calculation may be performed artificially. Further, the X-ray diffraction measurement device is a device that only forms a diffraction ring, the imaging plate 15 on which the diffraction ring is formed is detached from the table 16 and set in another device to detect the intensity distribution of the diffraction X-ray, and the diffraction ring. The erasure may be performed by another device.

  In the above embodiment, the half-value width is used as the width based on the intensity distribution in the radial direction of the diffraction ring. However, if the width is based on the intensity distribution in the radial direction of the diffraction ring, other values are used. Also good. For example, an integral width may be used, or a width obtained by slicing at a level 1 / β of the peak value and β being set to an appropriate value may be used.

  Moreover, in the said embodiment, although it was set as the structure which can adjust the position and attitude | position of the measurement target OB using the moving mechanism and rotation mechanism of the target set apparatus 60, the measurement target OB is fixed and X-ray diffraction measurement is carried out. The housing 50 of the apparatus may be connected to an arm type moving device or the like to adjust the position and posture of the housing 50 with respect to the measurement object OB. In this case, it is effective when the measurement object OB is a heavy object or is fixed and difficult to transport.

  In the embodiment and the modification, a diffraction ring is formed on the imaging plate 15, and the intensity distribution corresponding to the intensity of the diffracted X-rays in the diffraction ring is obtained by laser irradiation from the laser irradiation device 30 and light intensity detection. Detecting and erasing the diffraction ring by irradiating with LED light. If the diffraction ring is formed and its intensity distribution can be detected, what kind of method is used to form the diffraction ring and detect the intensity distribution? It may be used. For example, instead of the imaging plate 15, an X-ray CCD having a plane as wide as the imaging plate 15 is provided, and when X-ray irradiation from the X-ray emitter 10 is performed, an electric signal output from each pixel of the X-ray CCD is used. You may make it detect the intensity distribution in a diffraction ring. Further, instead of the X-ray CCD having the same area as the imaging plate 15, the X-ray CCD having a small size is scanned while detecting the position, and the electric signal output from each pixel of the X-ray CCD and the X-ray CCD. You may make it detect the intensity distribution in a diffraction ring from a scanning position.

DESCRIPTION OF SYMBOLS 10 ... X-ray emitter, 15 ... Imaging plate, 15a, 16a, 17a, 18a, 21a, 26a, 27a1, 27b ... Through-hole, 16 ... Table, 18 ... Fixing tool, 20 ... Table drive mechanism, 21 ... Moving stage , 22 ... feed motor, 23 ... screw rod, 27 ... spindle motor, 28 ... passage member, 30 ... laser detector, 31 ... laser light source, 36 ... objective lens, 44 ... LED light source, 45 ... plate, 46 ... motor, 47a, 47b ... stopper member, 48 ... imaging lens, 49 ... imaging device, 50 ... housing, 50a ... bottom wall, 50c ... notch wall, 50d ... connecting wall, 52 ... support rod, 60 ... target set Device 61 ... Stage 63a, 65a, 66a, 67a, 68a ... Operator 90 ... Computer device 91 ... Controller 92 Input device, 93 ... display, 95 ... high voltage power supply, OB ... measurement object

Claims (5)

An X-ray emitter that emits X-rays toward a target measurement object;
X-ray radiated from the X-ray emitter toward the measurement object, and X-ray diffracted light generated at the measurement object is applied to the optical axis of the X-ray emitted from the X-ray emitter. An object to be measured using an X-ray diffractometer that includes a diffraction ring forming unit that receives light on an imaging surface that intersects perpendicularly and forms a diffraction ring that is an image of the X-ray diffracted light on the imaging surface. In the surface hardness evaluation method,
A diffractive ring forming step of forming a diffractive ring by the diffractive ring forming means;
A diffraction ring intensity distribution detection step for detecting a distribution of intensity corresponding to the intensity of the X-ray diffracted light in the diffraction ring formed by the diffraction ring formation step;
Based on the intensity distribution detected by the diffraction ring intensity distribution detection step, a diffraction ring width that is a width based on an intensity distribution in the radial direction of the diffraction ring is calculated at a plurality of locations of the diffraction ring, and the diffraction ring width is calculated. Diffractive ring width change curve calculating step for calculating a change curve with respect to the circumferential direction of the diffractive ring,
From the diffraction ring width change curve calculated by the diffraction ring width change curve calculation step, a diffraction ring width average step of calculating an average value of the diffraction ring width;
Surface hardness for calculating the surface hardness of the object to be measured using the average value of the diffraction ring width obtained by the diffraction ring width averaging step and the relationship between the diffraction ring width and the surface hardness acquired in advance. A method for evaluating the surface hardness of an object to be measured, comprising performing a calculation step. In the surface hardness evaluation method of the measuring object according to claim 1 ,
The diffraction ring width averaging step calculates a parameter in a reference change curve when a reference change curve whose curve shape is set in advance matches the calculated change curve, and calculates the diffraction ring width from the calculated parameter. A method for evaluating the surface hardness of an object to be measured, comprising calculating an average value. In the surface hardness evaluation method of the measuring object according to claim 2 ,
In the diffraction ring width change curve calculation step, after calculating the change curve, the deviation of the calculated curve shape of the change curve from the curve shape of the reference change curve is calculated, and the calculated deviation is set to a preset tolerance. A method for evaluating the surface hardness of an object to be measured, wherein a portion exceeding the value is excluded from the calculated change curve . In the surface hardness evaluation method of the measuring object according to claim 1 to claim 3 ,
The diffraction ring forming step is performed after the incident angle of the X-ray from the X-ray emitter to the measurement object is set to 10 degrees or more,
Based on the intensity distribution detected by the diffraction ring intensity distribution detection step, the shape of the diffraction ring is detected, and the residual stress of the object to be measured is calculated from the detected shape of the diffraction ring using the cos α method. A method for evaluating the surface hardness of a measurement object, comprising performing a calculation step. An X-ray emitter that emits X-rays toward a target measurement object;
X-ray radiated from the X-ray emitter toward the measurement object, and X-ray diffracted light generated at the measurement object is applied to the optical axis of the X-ray emitted from the X-ray emitter. Diffractive ring forming means for receiving light at imaging surfaces that intersect perpendicularly to each other and forming a diffraction ring that is an image of the X-ray diffracted light on the imaging surface;
Diffractive ring intensity distribution detecting means for detecting an intensity distribution corresponding to the intensity of X-ray diffracted light in the diffractive ring formed by the diffractive ring forming means;
Based on the intensity distribution detected by the diffraction ring intensity distribution detecting means, a diffraction ring width, which is a width based on the intensity distribution in the radial direction of the diffraction ring, is calculated at a plurality of locations of the diffraction ring, and the diffraction ring width is calculated. Diffractive ring width change curve calculating means for calculating a change curve with respect to the circumferential direction of the diffractive ring,
From the diffraction ring width change curve calculated by the diffraction ring width change curve calculation means, a diffraction ring width average means for calculating an average value of the diffraction ring width;
The surface hardness of the measurement object is calculated using the average value of the diffraction ring width obtained by the diffraction ring width averaging means and the relationship between the previously obtained diffraction ring width and the surface hardness of the object. An X-ray diffraction measurement apparatus comprising a surface hardness calculation means.