JPS6234295Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an X-ray analysis device that uses an electron beam to measure a wide two-dimensional distribution of inclusions in a large area steel sample such as a cross section of a slab.

In the sulfur print test method, a photographic paper soaked in sulfuric acid solution is attached to the surface to be tested (for example, a cross section of a slab) in order to detect the segregation and distribution state of sulfur (S) in steel materials. Since the smoothness is required to be on the same level as No. 1, it has the drawback that polishing requires a large amount of time. Moreover, only sulfur and phosphorus can be directly detected with sulfur print, and other inclusions cannot be directly observed. Among inclusions other than sulfur, aluminum (Al), manganese (Mn), etc. are alumina (Al ₂ O ₃ ) or sulfur compounds (e.g. MnS) that behave in the same way as sulfur.
This was estimated empirically from the distribution pattern of sulfur prints, but as the content of sulfur in steel materials has decreased in recent years, these measurements tend to become increasingly difficult.

On the other hand, there is an X-ray microanalyzer (EPMA) as a device that directly measures various inclusions on a surface to be inspected. This method involves irradiating a sample with an electron beam with a very narrow beam diameter (1 to 100μφ), detecting the X-rays emitted from the inclusions, and determining the elements and amount of the inclusions.
Although it is a dimensional measurement, since it is an X-ray condensing method that uses a curved crystal in the X-ray spectroscopy system, the Rowland circle (concentrating circle) is located below the sample position. Therefore, the size of the sample is limited, and only about 20 x 20 mm ² can be analyzed. Therefore, the scanning range is 1 to several mm.
Because the area is so narrow, it is not suitable for obtaining a wide distribution pattern like a sulfur print, and the surface to be examined requires a flatness similar to that of an electron microscope sample, so it takes time to polish it. is similar to sulfa print.

In order to solve this problem, the present inventors have proposed an X-ray analyzer that measures the cross section of a slab over a wide range using an electron beam with a beam diameter selected in the range of 0.1 to 10 mm. The outline will be explained with reference to FIG. In this figure, reference numeral 1 denotes a metal material multi-element simultaneous distribution measuring device, and everything other than the electron gun and electron optical system of the device is kept in a vacuum container. 2 is a pulse motor 3,
4 is a sample stage that moves in the X and Y directions,
A sample 5 is placed on the top surface. Sample 5
For example, the width (Y direction) is 30 cm and the length (X direction) is 2 m.
The cross-section of a CC (continuously cast) slab of approximately Ru. 7a to 7d are X-ray spectrometers that use planar crystals as spectroscopic crystals, which detect characteristic X-rays of Al, P, S, and Mn and convert them into electric signals (one pulse equals one X-ray quantum). (equivalent pulse train). 8 is a high voltage circuit that applies a high voltage for acceleration to the electron gun 6;
Its output is confirmed through the high pressure control system 10. The beam diameter of the electron beam EB is controlled by changing the voltage applied from the beam control circuit 11 to the electron lens 6a, and the degree of vacuum inside the apparatus 1 is confirmed through the vacuum state detection section 12. 13a to 13d are counters that count the output pulses of the X-ray spectrometers 7a to 7d, respectively, and the counting period thereof is defined (gate controlled) by the gate control circuit 14. The pulse motors 3 and 4 are connected to the X-axis pulse generation circuit 15 and the Y
Each is driven by the output of the axial pulse generation circuit 16, and changes the electron beam EB irradiation position on the sample 5 in the same manner as television scanning. Reference numeral 17 denotes an alarm circuit, which turns on the lamp 9 if any abnormality occurs. Reference numeral 20 denotes a data processing system for control analysis, which includes a microcomputer 21, a minicomputer system 22, and a graphic display 23. The minicomputer system includes a minicomputer main body 24, an analysis calculation memory 25,
A data bus 2 is connected between the main body 24 and the microcomputer 21 and between the memory 25 and the display 23.
Connected at 7,28. 29 is a line for control signals.

According to the above-mentioned X-ray analyzer, it is possible to obtain an inclusion distribution pattern similar to that of sulfur print even if the polishing of the cross section of the slab as the surface to be inspected is extremely simple, and moreover, it is possible to obtain an inclusion distribution pattern similar to that of sulfur aprint, regardless of the content of sulfur. It has the advantage of directly measuring a wide range of distribution patterns of other inclusions. By the way, in this apparatus, a magnetic crane is used to carry the sample because it is necessary for one operator to carry the sample 5 onto the sample stage 2 and perform the analysis operation in order to save labor. However, in this method, sample 5 is magnetized;
The magnetic field generated by the magnetized sample 5 may cause the irradiation position of the electron beam EB to deviate from the normal point. The elemental analysis value obtained by irradiating one point of the sample 5 with the electron beam EB is written into the memory using the X, Y position coordinates of the sample 5 specified by the pulse motor as an address, and the two-dimensional distribution state of the inclusions is analyzed. A map shown is created, and the display 23 is operated by this map readout signal, so that the electron beam EB does not move straight, but deviates from the planned position, resulting in sample 5 being
If the light is incident on the surface, the image pattern (element distribution pattern) displayed on the display 23 will be different from the actual one. To avoid this, demagnetization can be performed, but in the conventional method of passing the material to be demagnetized through a demagnetizing coil, sample 5, which is the object of the present invention, has a width of 30 mm, like the cross section of a continuous cast slab.
Since the degaussing coil is large, with a length of 2 m and a length of 2 m, the degaussing coil must be large and must be installed at the entrance of the measuring device 1, resulting in large and expensive equipment.

The present invention solves such problems and is extremely simple.
This method attempts to perform reliable demagnetization using an inexpensive method, and involves irradiating a large area steel sample in a vacuum with an electron beam with a beam diameter selected in the range of 0.1 to 10 mm, and scanning the sample by moving it. In an X-ray analysis apparatus for measuring inclusions in the sample, a demagnetizing coil is connected to the sample in order to demagnetize the irradiated area of the sample guided to the electron beam irradiation position before the electron beam irradiation position. It is characterized in that it is disposed in front of the electron beam irradiation position with a small distance above the surface of the area to be irradiated with the electron beam. This will be explained in detail below with reference to the illustrated embodiments.

FIG. 2 shows an embodiment of the present invention, and the same parts as in FIG. 1 are given the same reference numerals. The computer 30 corresponds to the microcomputer 21 or minicomputer 24 in FIG. 1, and the sample movement control circuit 31 selectively drives the pulse motors 3 and 4 according to its control program. Pulse oscillation circuit 32
The drive circuit 33 is a combination of the X-axis and Y-axis pulse generation circuits 15 and 16 shown in FIG. (including the amount and direction of movement on the Y axis), the pulse motors 3 and 4 are rotated by the required steps. The irradiation position P of the electron beam EB is fixed and is located at two points in the X and Y directions of the sample 5.
Due to the dimensional movement, the surface of the sample 5 is scanned two-dimensionally. Demagnetizing coils 34A to 34D are demagnetized by coil drivers 35A to 35D. 36 is a coil driver 35A to 35 based on the X-axis information and Y-axis information from the control circuit 31.
This is a direction discrimination circuit that is selectively activated in D.

The degaussing coils 34A, 34C are fixedly provided symmetrically on the X-axis with the irradiation position P as the center by holding means (not shown), and the degaussing coils 34B,
34D is provided symmetrically on the Y axis with the irradiation position P as the center. The degaussing coils 34A to 34D are coils having, for example, 50 to 100 turns, and are supplied with an alternating current of about 1 A. Demagnetizing coil 34A (34B
34D) is placed close to the surface of the sample 5 at a distance of about 0.5 to 1 mm, as shown in Figure 3a, and the magnetic flux of the coil causes the electron beam to
30~ between the irradiation position P and the EB so as not to deflect the EB.
Leave a distance of about 50mm. In order to completely eliminate the influence, it is preferable to provide a magnetic shield such as a magnetic ring, although not shown. FIG. 3b shows the coil arrangement, and arrows X _A , X _C , Y _B , and Y _D indicate the moving directions of the sample 5, respectively. Degaussing coil 34A, 34
C is selected when the sample 5 moves in the X _A (X _C ) direction, and degaussing coils 34B and 34D are selected when the sample 5 moves in the Y _B (Y _D ) direction. Therefore, as shown in Figure 3a, sample 5 is
When moving in direction _A , the irradiated area 5a that reaches the irradiation position P is moved to the irradiation position P by the degaussing coil 34A.
It is possible to demagnetize locally in front of the

FIG. 4 is a block diagram of main parts showing another embodiment of the present invention. In the above embodiment, four fixedly arranged degaussing coils were selectively used depending on the moving direction of the sample 5, but in this embodiment, a ring 40 having a single degaussing coil was used at the irradiation position P. It is arranged to be rotatable around the center, and its rotational position is changed by a motor 41. The motor 41 is controlled by a drive control circuit 42, to which two pieces of information are fed back. One is information from the rotational angle movement sensor 43, and the other is information obtained by detecting four through holes 44A to 44D drilled in the ring 40. In the latter case, light from a light source 45 is detected by a photodetector 46, and its photoelectric conversion output is amplified by an amplifier 47. Now, if the degaussing coil 34 (see FIG. 5) provided in the ring 40 is at the same position as the coil 34A in FIG. 41 to sequentially connect the through holes 44B, 44C, and 44D to the photodetector 46.
When the degaussing coil 3 is rotated to the position detected by
4 are degaussing coils 34B, 34C, and 34D in Fig. 3.
Move to the same position sequentially. Therefore, the degaussing coil 3
By changing the rotational position of the sample 4 in accordance with the moving direction of the sample 5, the irradiated region of the sample 5 can be locally demagnetized in front of the irradiation position P, as in the previous embodiment. Further, the rotation angle movement sensor 43 generates pulses as the motor and therefore the ring 40 rotate, and the count value of the pulses indicates the rotation angle, so the desired angle is given as a numerical value, and the count value of the output pulses of the sensor 43 is The degaussing coil can be moved to any desired angular position by rotating the motor until it becomes equal to .

As mentioned above, in the present invention, since the electron beam irradiation area of the sample is locally demagnetized in advance, the electron beam can be reliably guided to the proper irradiation position even if the sample is magnetized before being delivered. . Moreover,
Degaussing by a degaussing device (degaussing coil) is performed locally and sequentially in parallel with electron beam scanning after the sample is introduced into the vacuum system of the X-ray analyzer, so a degaussing line is provided externally in advance and a separate process Compared to the method of demagnetizing the sample, this method has the advantage of being able to shorten the process by one step and simplifying the device configuration. The embodiment shown in Fig. 4 has the advantage of requiring only one degaussing coil, but if multiple demagnetizing coils are used as in the embodiment shown in Fig. 2, a rotation mechanism cannot be incorporated into the vacuum system. This has the advantage of being unnecessary.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an X-ray analyzer using a large diameter electron beam, Fig. 2 is a schematic diagram showing an embodiment of the present invention, and Figs. 3a and b are degaussing coils shown in Fig. 2. 4 is a main part configuration diagram showing another embodiment of the present invention, and FIG. 5 is a positional relationship of a single degaussing coil used to explain the operation of FIG. 4. FIG. 1... Metal material multi-element simultaneous analysis device, 3, 4...
...Pulse motor, 5...Sample, 5a...Irradiation area, 6...Electron gun, 34, 34A to 34D...
...Degaussing coil, P...irradiation position, EB...electron beam.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A large-area steel sample is irradiated with an electron beam with a beam diameter selected in the range of 0.1 to 10 mm in a vacuum, and the sample is moved and scanned to detect the inside of the sample. In an X-ray analysis device that measures inclusions, a degaussing coil is scheduled to be irradiated with the electron beam of the sample in order to demagnetize the irradiated area of the sample guided to the electron beam irradiation position before the electron beam irradiation position. 1. An X-ray analysis device for steel samples, characterized in that a booth is placed on the surface of the area and placed in front of an electron beam irradiation position. (2) A steel sample is placed on a sample stage that is moved in the X and Y directions by a motor, and four degaussing coils are fixedly arranged in the X and Y directions with the electron beam irradiation position as the center. 2. The X-ray analysis apparatus for a steel sample according to claim 1, wherein a coil in the direction of movement and in front of the irradiation position is excited depending on the direction of movement. (3) A steel sample is placed on a sample stage that is moved by a motor, and a degaussing coil is attached to a ring that rotates around the electron beam irradiation position, and rotates in accordance with the moving direction of the sample stage so that the degaussing coil is placed in front of the irradiation position. An X-ray analysis apparatus for a steel sample according to claim 1, which is characterized in that it is configured so as to be arranged as follows.