JP2011227056A - Element mapping method, element mapping device, and method for manufacturing steel product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a distribution state of high concentration elements and low concentration elements other than main component elements contained in a steel material.SOLUTION: An electron beam source 2 irradiates an electron beam E to a steel material S. WDX3 measures a distribution state of low concentration elements other than main component elements contained in the steel material S by detecting X ray generated from irradiation of the electron beam E. EDX4 measures a distribution state of high concentration elements other than the main component elements by detecting X ray transmitted through a filter 7 made of a Cr foil, thereby enabling to measure the distribution state of the high concentration elements and the low concentration elements other than the main component elements contained in the steel material S simultaneously and with high accuracy.

Description

  The present invention relates to an element mapping method and element mapping apparatus for measuring a distribution state of elements contained in a steel material, and a method for manufacturing a steel product based on the element distribution state measured by the element mapping method. It is about.

  Conventionally, an electron probe microanalyzer (EPMA) has been mainly used as an element mapping apparatus for measuring the distribution state of elements contained in a sample. This EPMA is composed of a wavelength dispersive X-ray detector (WDX). That is, EPMA irradiates a sample with an electron beam, and selects X-rays (characteristic X-rays) having a wavelength corresponding to the element to be measured from the X-rays having various wavelengths generated at that time. By measuring the intensity of characteristic X-rays with a detector, the distribution state of elements contained in the sample is measured. Since EPMA can usually be equipped with up to five WDXs, EPMA can simultaneously measure distribution states of up to five elements.

  In the measurement method using EPMA, when elements with different concentrations (hereinafter, high-concentration elements and low-concentration elements) coexist in the sample, the distribution state of both elements is to be measured simultaneously in one measurement. Then, the following first and second problems occur. The first problem is that if the irradiation current amount of the electron beam is suppressed to an optimum irradiation current amount for the high concentration element so that the X-ray intensity is not counted down at the detector, the characteristic X-ray of the low concentration element is obtained. This is a problem that the measurement accuracy of the low-concentration element is deteriorated because the strength of is extremely small. The second problem is that when the irradiation current amount of the electron beam is increased so that the measurement accuracy of the low concentration element is improved, the measurement accuracy of the high concentration element is deteriorated. This is because when the amount of electron beam irradiation current is increased, the intensity of the characteristic X-rays of the high-concentration elements becomes too large, causing the X-ray intensity to be counted off at the detector, and the intensity of the characteristic X-rays is accurately determined. This is because it becomes impossible to measure.

  In general, high-precision measurement that can be used for process analysis is difficult unless EPMA is used. However, as described above, simultaneous measurement under a plurality of conditions on the same sample cannot be performed with EPMA. For this reason, in the measurement method using EPMA, when high-accuracy measurement is required for both high-concentration elements and low-concentration elements, measurement must be performed twice under different measurement conditions. However, generally, since it takes a lot of time to measure the distribution state of elements, it is not actually performed to measure twice under different measurement conditions. That is, when a high-concentration element and a low-concentration element coexist in a sample, the element distribution state is measured at the expense of measurement accuracy for either element.

  In order to simultaneously measure the distribution state of the high-concentration element and the low-concentration element with high accuracy, it is conceivable to apply the techniques described in Patent Document 1 and Patent Document 2 to EPMA. Specifically, the technique described in Patent Document 1 relates to an apparatus called an X-ray microanalyzer in which WDX and an energy dispersive X-ray detector (EDX) are mounted in one apparatus, and uses a light element filter. By reducing the intensity of X-rays incident on the EDX, WDX measurement and EDX measurement are performed under the same analysis conditions. On the other hand, the technique described in Patent Document 2 relates to a fluorescent X-ray analyzer, which attenuates X-rays generated from Si, which is a main component element of a silicon wafer, by an Al filter having an atomic number one smaller than Si. Thus, the concentration of Fe or Ni other than Si is detected. In EDX, a sample is irradiated with an electron beam, and X-rays of various energies generated at that time are simultaneously detected for each energy. According to EDX, it is possible to measure the distribution state of all elements existing within the energy range detected by the energy of characteristic X-rays.

JP 60-257051 A JP 2000-55839 A

  However, when the techniques described in Patent Documents 1 and 2 are applied to EPMA to measure the distribution state of high-concentration elements and low-concentration elements other than Fe, which is a main component element contained in steel materials, the following is shown. Such a problem occurs. That is, when the technique described in Patent Document 1 is applied to EPMA and the distribution state of elements contained in the steel material is measured, most of the X-ray intensity detected by EDX is occupied by the characteristic X-ray intensity of Fe. . For this reason, in order to detect clearly the distribution state of elements other than Fe contained in the steel material, the X-ray intensity integration time must be measured at least on the order of seconds. Accordingly, even if the technique described in Patent Document 1 is applied to EPMA in which the integration time per point is on the order of several tens of milliseconds, the distribution state of elements other than Fe can hardly be detected. The distribution state of the high concentration element and the low concentration element cannot be measured.

  Moreover, when measuring the distribution state of the elements contained in the steel material by applying the technique described in Patent Document 2 to EPMA, the intensity of the characteristic X-rays of Fe and Ni is also reduced by passing through the filter. X-ray intensity sufficient for measurement of the distribution state of is not obtained. In particular, in order to measure the distribution of Mn, which is a high-concentration element contained in steel materials, but with an overwhelmingly lower concentration than Fe, which is the main component, the intensity of the characteristic X-ray of Fe is greatly reduced. Therefore, it is necessary to increase the intensity of the characteristic X-ray of Mn. However, even if, for example, Mn having an atomic number 1 smaller than Fe is simply applied to the filter by applying the technique described in Patent Document 2, the mass absorption coefficient of Mn is small with respect to the energy of FeKα rays that are characteristic X-rays of Fe. For this reason, the intensity of the characteristic X-rays of Fe cannot be greatly reduced to increase the intensity of the characteristic X-rays of Mn. Needless to say, it is more difficult to simultaneously measure an element at a lower concentration than Mn.

  For this reason, when the distribution state of the elements contained in the steel material is measured by applying the technique described in Patent Document 2 to EPMA, most of the X-ray intensity is occupied by the characteristic X-ray intensity of Fe. Since the device described in Document 2 is a fluorescent X-ray analyzer, in order to clearly detect the distribution state of elements other than Fe, the accumulated time of X-ray intensity must be measured at least on the order of seconds. Don't be. Therefore, even if the technique described in Patent Document 2 is applied to EPMA in which the integration time per point is performed on the order of several tens of milliseconds, the distribution state of elements other than Fe can hardly be detected. The distribution state of the high concentration element and the low concentration element cannot be measured.

  From the above, it has been expected to provide a technique capable of simultaneously and highly accurately measuring the distribution state of high-concentration elements other than Fe and low-concentration elements contained in steel materials. In the present specification, the high concentration element means an element having a concentration of at least twice or more by mass% with respect to the concentration of the low concentration element. However, in order to achieve the effect of the present invention more effectively, the concentration of the high concentration element is preferably 10 times or more by mass% with respect to the concentration of the low concentration element. Further, examples of the high concentration element include Mn, Cr, and Mo, and examples of the low concentration element include Nb, S, P, Si, Cu, and V.

  The present invention has been made in view of the above problems, and its purpose is to simultaneously and highly accurately measure the distribution state of high-concentration elements and low-concentration elements other than the main component elements contained in the steel material. It is an object to provide a possible element mapping method and element mapping apparatus. Moreover, the other object of this invention is to provide the manufacturing method of the steel products which can improve the yield of steel products.

  In order to solve the above problems and achieve the object, an element mapping method according to the present invention includes a step of irradiating a steel material with an electron beam, and an X-ray generated along with the irradiation of the electron beam. A first step of measuring a distribution state of a first element other than a main component element contained in the steel material by detecting with a detector, and the X-ray transmitted through a filter made of chrome foil is an energy dispersive type A second step of measuring a distribution state of a second element having a concentration higher than that of the first element, which is an element other than the main component element contained in the steel material by detecting with an X-ray detector; The first step and the second step are executed simultaneously.

  In order to solve the above-described problems and achieve the object, an element mapping apparatus according to the present invention detects an electron beam source that irradiates a steel material with an electron beam, and X-rays generated by the irradiation of the electron beam. By detecting the X-ray transmitted through a filter made of a chrome foil and a wavelength dispersive X-ray detector that measures the distribution state of the first element other than the main component element contained in the steel material, An energy dispersive X-ray detector that measures a distribution state of a second element that is an element other than the main component contained in the steel material and has a higher concentration than the first element.

  In order to solve the above problems and achieve the object, a method for manufacturing a steel product according to the present invention includes a step of manufacturing a steel product using a continuous casting machine, and the steel product using the element mapping method according to the present invention. Measuring the distribution state of elements other than the main component elements contained in the element, and controlling the operating conditions of the continuous casting machine based on the measurement result of the distribution state of the elements.

  According to the element mapping method and the element mapping apparatus according to the present invention, the distribution state of the high concentration element and the low concentration element other than the main component element contained in the steel material can be measured simultaneously and with high accuracy. Moreover, according to the manufacturing method of the steel product which concerns on this invention, the yield of steel products can be improved.

FIG. 1 is a block diagram showing a configuration of an element mapping apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of an X-ray spectrum obtained when no Cr foil is placed. FIG. 3 is a diagram showing an example of an X-ray spectrum obtained when a Cr foil is placed. FIG. 4 is a diagram showing an element mapping result of Nb using an element mapping apparatus according to an embodiment of the present invention. FIG. 5 is a diagram in which the intensity of the characteristic X-ray of Nb is displayed three-dimensionally. FIG. 6 is a diagram showing an element mapping result of Mn using an element mapping apparatus according to an embodiment of the present invention. FIG. 7 is a diagram in which the intensity of characteristic X-rays of Mn is displayed three-dimensionally. FIG. 8 is a schematic diagram showing a schematic configuration of a continuous casting machine used in the continuous casting process.

  Hereinafter, an element mapping method and an element mapping apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[Configuration of element mapping equipment]
First, with reference to FIG. 1, the structure of the element mapping apparatus which is one Embodiment of this invention is demonstrated.

  FIG. 1 is a block diagram showing a configuration of an element mapping apparatus according to an embodiment of the present invention. As shown in FIG. 1, an element mapping apparatus 1 according to an embodiment of the present invention includes an electron beam source 2, a wavelength dispersive X-ray detector (WDX) 3, and an energy dispersive X-ray detector (EDX) 4. As a main component. The electron beam source 2 irradiates the steel material S with the electron beam E. The irradiation current amount of the electron beam E is adjusted according to the detection ability of WDX3.

  The WDX 3 includes a spectral crystal 5 and a detector 6. The spectral crystal 5 selects X-rays (characteristic X-rays) X2 having a wavelength corresponding to the element to be measured contained in the steel material S from the X-rays X1 generated by irradiating the steel material S with the electron beam E. Then, the selected characteristic X-ray X2 is supplied to the detector 6. The detector 6 measures the distribution state of the element to be measured by detecting the intensity of the characteristic X-ray X2. As the detector 6, it is preferable to use a proportional counter with a short dead time so that the characteristic X-ray X 2 can be measured at a high count rate. In this case, it is desirable that the count rate of the proportional counter tube is about 60000 cps.

The EDX 4 includes a filter 7 and a detector 8. The filter 7 is for reducing the intensity of the characteristic X-ray of Fe contained in the X-ray X1 generated by irradiating the steel material S with the electron beam E. As the filter 7, it is desirable to use a Cr foil, the mass absorption coefficient for FeKα ray which is a characteristic X-ray of Fe is 463 cm ² / g, and the mass absorption coefficient for MnKα ray which is a characteristic X-ray of Mn is 62. It is preferable to use a Cr foil having a thickness of 3 cm ² / g and a thickness in the range of 5 to 50 μm. The placement method of the filter 7 may be any placement method as long as the filter 7 covers the light receiving surface of the detector 8.

  For example, when a Cr foil having a thickness of 30 μm is placed as the filter 7, the intensity of the FeKα ray, which is the characteristic X-ray of Fe, becomes 0.000046 after the Cr foil is transmitted with respect to the incident intensity of 1 and greatly decreases. On the other hand, the intensity of the MnKα ray, which is the characteristic X-ray of Mn, which is the main element of the steel material S having an element number one smaller than that of Fe, is 0.26 after the Cr foil transmission with respect to the incident intensity of 1, The amount of decrease is small compared to FeKα rays. For this reason, when Cr foil is not placed, as shown in FIG. 2, the ratio of the intensity of MnKα ray to the total intensity of X-ray X1 is about 3%, whereas Cr foil is placed As shown in FIG. 3, the ratio of the intensity of the MnKα ray to the total intensity of the X-ray X1 increases to about 21%. That is, by placing the Cr foil, the intensity of the MnKα line can be increased to 7 times. This is because the strength of FeKα rays, FeKβ rays, and FeL rays, which are Fe characteristic X-rays, is greatly reduced by Cr foil, whereas the intensity of MnKα rays, which are Mn characteristic X-rays, is slightly reduced. This is because it can be suppressed.

  The detector 8 measures the distribution state of the element to be measured contained in the steel material S by detecting the X-ray X1 transmitted through the filter 7 for each energy. As the detector 8, it is desirable to use a silicon drift detector (SDD) having a counting rate of 50000 cps or more. In the conventional EDX, a semiconductor detector (SSD) is used as a detector. However, the count rate of SSD is about 10,000 cps, which is lower than the count rate of WDX3 (about 60000 cps). WDX3 can measure X-ray intensity of about 60,000 cps for one element, whereas SSD has a total intensity in the entire energy range, that is, a count rate of the total element intensity in the steel material S. 10000 cps. For this reason, focusing on one element, the SSD count rate is two or more orders of magnitude lower than the WDX3 count rate, although it depends on the concentration.

  For this reason, when an SSD is used as the detector 8, it becomes difficult to measure at the same level as WDX3. In contrast, when the SDD is used as the detector 8, the count rate of the EDX4 can be made closer to the count rate of the WDX3 because the count rate of the SDD is one digit or more larger than the count rate of the SSD. The reason why the count rate of EDX4 should be 50000 cps or more is that if the count rate is 50000 cps or more, among the spectroscopic crystals constituting WDX3, the count rate is at least the same level as the spectroscopic crystal having a low count rate. This is because it can be secured. A counting rate of 100000 cps or more is more preferable because the counting rate can be secured to the same level as that of a crystal having a high counting rate among the spectral crystals. However, the detector 8 is not limited to the SDD, and may be any type as long as it satisfies the above-described count rate condition.

  Although the count rate of EDX4 can be improved by using SDD as the detector 8, the count rate is still insufficient as compared with the count rate of WDX3. However, as described above, in the element mapping apparatus 1, the filter 7 is disposed between the steel material S and the EDX 4, and the filter 7 reduces the intensity of the characteristic X-ray of Fe contained in the X-ray X1. As a result, the strength ratio of the element to be measured is increased. Therefore, according to the element mapping apparatus 1, the EDX 4 can perform measurement with accuracy and time that can withstand process analysis and the like in a measurement time (at least twice as long) as that of the WDX 3. Specifically, by using the filter 7 to increase the intensity ratio of the element to be measured by 7 times, and further using an SDD capable of counting 10 times or more of SSD as the detector 8, there is no conventional Cr foil filter, Compared with an apparatus using an SSD as a detector, the intensity measurement can be performed about 100 times in the same measurement time, and the element distribution state can be measured in a short time.

[Element mapping method]
Next, an element mapping method that is an embodiment of the present invention using the element mapping apparatus 1 will be described.

  In the element mapping method according to an embodiment of the present invention, first, the electron beam source 2 irradiates the steel material S with the electron beam E. Next, the WDX 3 sorts the characteristic X-ray X2 of the low-concentration element from the X-ray X1 generated by the irradiation of the electron beam E by the spectroscopic crystal 5, and the detector 6 determines the intensity of the selected characteristic X-ray X2. The distribution state of low concentration elements is measured by Nb, S, P, Si, Cu, V etc. can be illustrated as a low concentration element. At the same time, the EDX 4 detects the X-ray X1 transmitted through the filter 7 for each energy to measure the distribution state of the high concentration element. Examples of the high concentration element include Mn, Cr, and Mo. Thereby, the distribution state of the high concentration element and the low concentration element other than the main component element contained in the steel material S can be measured simultaneously and with high accuracy.

  It should be noted that the irradiation current amount of the electron beam E is preferably adjusted so as to sufficiently obtain the characteristic X-ray intensity of the low concentration element. However, at this time, when the X-ray intensity of the detector 8 is counted down and the measurement accuracy on the EDX 4 side is lowered, the X-ray intensity of the detector 8 is adjusted by appropriately adjusting the thickness of the filter 7. It is better to suppress the occurrence of counting down. In this embodiment, the distribution state of the low concentration element and the high concentration element is measured on the WDX3 side and the EDX4 side, respectively. However, if the count rate of EDX4 can be made larger than the count rate of WDX3, the WDX3 side And the distribution state of the high concentration element and the low concentration element may be measured on the EDX4 side, respectively.

[Experimental example]
Next, the element mapping apparatus 1 according to an embodiment of the present invention and the conventional apparatus using the SSD as the detector 8 of the EDX 4 without installing the filter 7 are used for element mapping on the steel slab. The results of experiments conducted are shown below. Element mapping refers to dividing a region to be measured into a grid of a certain size and obtaining a two-dimensional distribution of concentration obtained from the intensity of X-rays by the intensity of X-rays or a calibration curve at each lattice point. means.

  In this experiment, a material 10 mm thick and about 80 mm wide cut out and polished from the central segregation portion of the C cross section of the steel slab was used as the steel material S. The thickness of the Cr foil constituting the filter 7 was 30 μm. The analysis conditions were such that the acceleration voltage, irradiation current, and beam diameter of the electron beam E were 25 kV, 5 μA, and 100 μm, respectively, and the integration time per measurement point was 10 msec. The analysis target elements of WDX4 and EDX5 were Nb and Mn, respectively. The time required for the measurement was about 13 minutes.

  FIG. 4 is a diagram showing an element mapping result of Nb using an element mapping apparatus according to an embodiment of the present invention. FIG. 5 is a diagram three-dimensionally displaying the intensity of the characteristic X-ray of Nb in the region R1 shown in FIG. As shown in FIGS. 4 and 5, the center segregation of Nb could be confirmed in the region R1 of the steel material S by using the element mapping apparatus 1 which is an embodiment of the present invention. The concentration of Nb determined from the intensity of the characteristic X-ray of Nb was 0.01 to 5% by mass.

  FIG. 6 is a diagram showing an element mapping result of Mn using an element mapping apparatus according to an embodiment of the present invention. FIG. 7 is a diagram three-dimensionally displaying the intensity of Mn in the region R2 shown in FIG. As shown in FIGS. 6 and 7, center segregation of Mn could be clearly confirmed in the region R2 of the steel material S by using the element mapping apparatus 1 which is an embodiment of the present invention.

  On the other hand, in elemental mapping using a conventional apparatus, since the characteristic X-ray intensity of Fe accounts for most of the X-ray intensity and the count rate of SSD is low, the characteristic X-ray intensity of Mn is per measurement point. Only a few to tens of counts were obtained, and as a result, central segregation of Mn could not be confirmed.

  Thereby, according to the element mapping apparatus 1 which is one embodiment of the present invention, it is confirmed that low-concentration Nb element mapping and high-concentration Mn element mapping can be performed quickly and with high accuracy. It was done. However, the combination of elements that can be elementally mapped is not limited to the combination of Nb and Mn. For example, elements such as S, P, Si, Cu, and V are used by WDX3, and elements such as Cr and Mo are used by EDX4. Can be mapped. In this case, the measurement conditions may be selected as appropriate.

[Application example]
The element mapping method which is one embodiment of the present invention can be used for process analysis of a continuous casting process, for example. FIG. 8 is a schematic diagram showing a schematic configuration of a continuous casting machine used in the continuous casting process. As shown in FIG. 8, the continuous casting machine 10 includes a tundish 12 into which molten steel 11 is poured from a ladle (not shown), and a molten steel 11 poured from the tundish 12 through an immersion nozzle 13 on the surface of the solidified shell. A copper mold 15 that is molded and semi-solidified until 14 grows into dendrites, a slab support roll 17a that cools the semi-solid slab 16 drawn from the mold 15 vertically downward, and a slab support roll A slab support roll 17b that cools and conveys the slab 16 drawn by 17a, a slab support roll 17c that cools and transports the slab 16 conveyed by the slab support roll 17b in the horizontal direction, and a slab support roll 17c. And a gas cutting machine 18 that manufactures a steel slab 19 by cutting the slab 16 conveyed by a predetermined length.

  Among steel slabs cast by such a continuous casting machine, the number of typical steel slabs that require evaluation of center segregation is about 3 to 4 per day. However, when measuring the distribution state of elements contained in a steel slab using conventional EPMA, a measurement time of about 20 hours is required for one slab. For this reason, in the conventional EPMA, only about one slab per day can be measured for the element distribution state, and it has not been applicable to the process analysis of the continuous casting process. On the other hand, according to the element mapping method according to an embodiment of the present invention, the element distribution state in the slab cross section having a width of about 2 m necessary for the quality evaluation of the steel slab is approximately 4 minutes of the measurement time by the conventional EPMA. Can be carried out in about 5 hours corresponding to 1.

  Therefore, according to the element mapping method which is one embodiment of the present invention, it is possible to evaluate 3 to 4 steel slabs per day, and it can be applied to process analysis of a continuous casting process. Moreover, the element distribution state of the steel slab manufactured by such a continuous casting machine 10 changes according to the operating conditions of the continuous casting machine 10 such as the cooling speed and the conveyance speed. Therefore, the element distribution state of the steel slab measured by the element mapping method according to one embodiment of the present invention and the operating conditions of the continuous casting machine 10 at that time are associated and stored in the database, and stored in the database. By controlling the operating conditions of the continuous casting machine 10 so that a desired element distribution state can be obtained based on the information, the steel product having the desired element distribution state is produced, and the production yield of the steel product is reduced. Can be improved.

  As is clear from the above description, according to the element mapping method and the element mapping apparatus which are one embodiment of the present invention, the steel material S is irradiated with the electron beam E, and X-rays generated along with the irradiation of the electron beam E are generated. Is detected by the detector 6, the distribution state of the low-concentration elements other than the main component elements contained in the steel material S is measured, and the X-ray transmitted through the filter 7 made of Cr foil is detected by the detector 8. Since the distribution state of high-concentration elements other than the main component elements is measured by means of the above, the distribution states of the high-concentration elements and low-concentration elements other than the main component elements contained in the steel material S are measured simultaneously and with high accuracy. Can do.

  Although the embodiment to which the invention made by the present inventor is applied has been described above, the present invention is not limited by the description and the drawings that form a part of the disclosure of the present invention according to this embodiment. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

  The present invention can be applied to the measurement of the distribution state of high-concentration elements and low-concentration elements other than the main component elements contained in the steel material.

DESCRIPTION OF SYMBOLS 1 Element mapping apparatus 2 Electron beam source 3 Wavelength dispersive X-ray detector (WDX)
4 Energy dispersive X-ray detector (EDX)
5 Spectroscopic crystal 6 Detector 7 Filter 8 Detector E Electron beam S Steel material X1, X2 X-ray

Claims (9)

Irradiating the steel material with an electron beam;
A first step of measuring a distribution state of a first element other than a main component element contained in the steel material by detecting a X-ray generated with irradiation of the electron beam with a wavelength dispersive X-ray detector. When,
By detecting the X-ray transmitted through the filter made of chrome foil with an energy dispersive X-ray detector, it is an element other than the main component element contained in the steel material and has a higher concentration than the first element. A second step of measuring a distribution state of the second element;
And the first step and the second step are performed simultaneously.   2. The element mapping method according to claim 1, wherein a counting rate of the energy dispersive X-ray detector is 50000 cps or more.   The element mapping method according to claim 1, wherein the energy dispersive X-ray detector includes a silicon drift detector.   The element mapping method according to claim 1, wherein the wavelength dispersion type X-ray detector includes a proportional counter. An electron beam source for irradiating the steel material with an electron beam;
A wavelength dispersive X-ray detector for measuring a distribution state of a first element other than a main component element contained in the steel material by detecting X-rays generated by irradiation with the electron beam;
An energy dispersive X-ray detector that measures a distribution state of a second element other than a main component element contained in the steel material by detecting the X-ray transmitted through a filter made of a chromium foil;
An element mapping apparatus comprising:   6. The element mapping apparatus according to claim 5, wherein a counting rate of the energy dispersive X-ray detector is 50000 cps or more.   The element mapping apparatus according to claim 5 or 6, wherein the energy dispersive X-ray detector includes a silicon drift detector.   The element mapping apparatus according to any one of claims 5 to 7, wherein the wavelength dispersion type X-ray detector includes a proportional counter. Producing steel products with a continuous casting machine;
Measuring a distribution state of elements other than the main component contained in the steel product using the element mapping method according to claim 1;
Controlling the operating conditions of the continuous casting machine based on the measurement result of the distribution state of the elements;
The manufacturing method of the steel product characterized by including.