JP2010125465A - Casting analyzer and casting analyzing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a casting analyzer and a casting analyzing method which can observe the solidified state of a molten metal in casting using a general X-ray source. <P>SOLUTION: The casting analyzer comprises: an X-ray emission means 1 having an X-ray source; a mold 2 for analysis having a cavity 20 through which X-rays emitted from the X-ray emission means 1 are transmitted and in which a molten metal is filled, and solidifying the molten metal to a direction almost orthogonal to the direction through which the X-rays are transmitted; and an X-ray detection means 3 installed on the side opposite to the X-ray emission means 1 with the mold 2 for analysis held and detecting the X-rays transmitted through the mold 2 for analysis as an image, and analyzes the solidified state of the molten metal in the cavity from the lightness of the transmitted X-ray image obtained by the X-ray detection means 3. In particular, by using at least either selected from the dimensions and material of the mold 2 for analysis in a suitable range, a clear transmitted X-ray image can be obtained, further, the solidification of the molten metal to the transmitting direction of the X-rays is satisfactorily suppressed, and it is made suitable for two-dimensional observation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a casting analysis apparatus and a casting analysis method that can be used for designing a casting method and evaluating a molten metal.

  Casting is a common method for producing metal parts. In casting, solidification proceeds by heat removal from the surface of the mold that the molten metal contacts. At this time, casting defects such as gas defects, shrinkage cavities, and segregation of solute elements may occur inside the casting. Since a casting defect becomes a starting point of fracture, it is regarded as a problem in casting quality. Such defects are difficult to remove completely by subsequent plastic working, and it is necessary to produce a high-quality casting by casting. Therefore, it is desired to grasp the state of the molten metal in the mold and to design a mold that can suppress the occurrence of casting defects inside the casting.

There is already a technique for observing the flow of molten metal in the cavity by photographing the molten metal supplied into the mold with X-rays. For example, in Patent Document 1, tracer particles having X-ray transmission characteristics different from that of the molten metal are mixed into the molten metal supplied into the mold, and the molten metal flow is visualized using an X-ray analyzer. ing. Further, in Non-Patent Document 1, nucleation / growth during solidification is observed in a thin metal melt having a thickness of 100 μm using a high-intensity synchrotron radiation facility (SPring-8).
JP 2007-54873 A H. Yasuda and eight others, “In-situ observation of nucleation, fragmentation and microstructure evolution”, Proceedings of 10th Asian Foundry Congress ), May 2008, p. 145-148

  In Patent Document 1, although the molten metal flow in the mold can be observed, the change from the liquid phase to the solid phase cannot be captured. This is because, in the first place, Patent Document 1 does not aim to distinguish between the liquid phase and the solid phase. If only the molten metal flow is observed, the contrast between the tracer particles, the molten metal, and the gas phase only needs to be clear. Therefore, the determination can be made only by irradiating the mold actually used during casting with X-rays. However, it is impossible to observe the solidification state of the molten metal under such observation conditions.

  On the other hand, in Non-Patent Document 1, it is possible to observe a change from a liquid phase to a solid phase. However, since SPring-8 cannot irradiate a wide area with X-rays with high parallelism, it can be observed only in a narrow range. That is, the use of SPring-8 is suitable for observing a fine structure, but is not suitable for observing a macroscopic coagulation state. Further, since SPring-8 is a very special facility, there is a problem that it cannot be easily used for analysis of a mold used for casting a product or evaluation of a molten metal.

  An object of this invention is to provide the casting analysis apparatus and casting analysis method which can observe the solidification state of the molten metal in casting using a general X-ray source in view of the said problem.

The casting analysis apparatus of the present invention includes an X-ray irradiation means having an X-ray source,
An analysis mold for solidifying the molten metal in a direction substantially perpendicular to the direction of transmission of X-rays having a cavity through which X-rays irradiated from the X-ray irradiation means are transmitted and filled with the molten metal;
X-ray detection means for detecting as an image X-rays installed on the opposite side of the X-ray irradiation means across the analysis template, and transmitted through the analysis template;
And analyzing the solidification state of the molten metal from the difference in brightness caused by the difference in the X-ray transmittance between the solid phase and the liquid phase of the transmitted X-ray image obtained by the X-ray detection means. Features.

  The “solidified state” specifically refers to the degree of solidification progress expressed by the amount of solid phase crystallization and the solid phase rate, the position of the solid-liquid interface (solidification interface), the crystallization time of the solid phase, the casting This includes the formation process of the nest, generation of bubbles due to dissolved gas contained in the molten metal, and the like.

  As described above, conventionally, the idea of analyzing the solidification state of the molten metal in the mold has never been found. The present inventors have focused on the fact that the transmitted X-ray image becomes darker as the solid phase increases in the solidification process. Therefore, the analysis mold for solidifying the molten metal is suitable for analyzing the solidification state of the molten metal by transmission X-ray images. That is, the casting analysis apparatus of the present invention includes an analysis mold for solidifying a molten metal in a direction substantially orthogonal to a direction through which X-rays are transmitted. Since the solidification progress direction is substantially perpendicular to the X-ray transmission direction, the solidification state can be observed two-dimensionally by a transmission X-ray image. In particular, by using at least one of the dimensions and material of the analysis mold within a suitable range, a clear transmitted X-ray image can be obtained, and solidification in the X-ray transmission direction can be well suppressed and two-dimensional. Suitable for observation.

  Note that the transmission X-ray image darkens as the solid phase increases in the solidification process of the molten metal because of the difference in density between the liquid phase and the solid phase. Since the density of the solid phase is higher than the density of the liquid phase, the more the solid phase exists, the more difficult it is to transmit X-rays. Therefore, it is possible to analyze the solidification state of the molten metal, especially the degree of solidification, the position of the solid-liquid interface (solidification interface), the crystallization time of the solid phase, etc. from the difference in the brightness of the transmitted X-ray image. Become.

  Furthermore, it is good to provide the brightness calculation means which calculates a brightness from at least one part of the said transmission X-ray image obtained by the said X-ray detection means. Since the solidification state of the molten metal can be quantified by the brightness calculation means, a more detailed solidification analysis is possible. Furthermore, it is good to provide the determination means which determines the cleanliness of the said molten metal when the brightness calculated by the said brightness calculation means exceeds a threshold value.

Further, the present invention can also be regarded as a casting analysis method. That is, the casting analysis method of the present invention is a casting analysis method for analyzing the molten metal filled in the analysis mold by X-ray,
A pouring step of pouring the molten metal into the analysis mold;
An X-ray irradiation step of irradiating the analysis mold with X-rays;
A solidification step of solidifying the molten metal filled in the analysis mold in a direction substantially orthogonal to a direction through which X-rays pass in parallel with the X-ray irradiation step;
An X-ray detection step for detecting, as an image, X-rays transmitted through the analysis template in parallel with the X-ray irradiation step;
A solidification analysis step of analyzing a solidification state of the molten metal from a difference in brightness caused by a difference in X-ray transmittance between at least a solid phase and a liquid phase of a transmission X-ray image obtained in the X-ray detection step;
It is characterized by including.

  The best mode for carrying out the casting analysis apparatus and the casting analysis method of the present invention will be described below.

[Casting analysis equipment]
The casting analysis apparatus of the present invention mainly includes an X-ray irradiation means, an analysis mold, and an X-ray detection means. And the solidification state of a molten metal is analyzed from the difference in the brightness of the transmitted X-ray image obtained by the X-ray detection means. As the molten metal analyzed by the casting analysis apparatus of the present invention, an aluminum alloy or a magnesium alloy that easily transmits X-rays is preferable.

  The X-ray irradiation means has an X-ray source. The X-ray irradiating means may be a simple one that has a general X-ray source, can be used for fluoroscopic photography, and can be installed in a factory or the like. If stipulated, the acceleration voltage for generating X-rays is 50 keV to 200 keV. If the acceleration voltage is too high, the transmitted X-ray image is hardly contrasted, and the difference between the solid phase and the liquid phase does not appear clearly, so that it is unsuitable for analyzing the solidification state of the molten metal.

The analysis mold transmits X-rays irradiated from the X-ray irradiation means. Therefore, it is preferable that the analysis mold is made of a size and a material that allow easy transmission of X-rays. The analysis mold has a front wall facing the X-ray irradiation means and a back wall facing the X-ray detection means (described later). The front wall and the back wall have a mass absorption coefficient μ for X-rays generated at an acceleration voltage of 80 keV. / [rho is 0.25 cm ² / g or less further may consists of a material which is 0.1~0.2cm ² / g. If the mass absorption coefficient exceeds 0.25 cm ² / g, X-rays that pass through the analysis mold are not sufficient, and a transmission X-ray image sufficient to analyze the solidification state of the molten metal cannot be obtained. . Specifically, graphite (0.160cm ² / g), calcium silicate (Nichias Co. Rumibodo: 0.242cm ² / g), alumina (0.185cm ² / g), mullite (0.187cm ² / g ) And the like. The mass absorption coefficient μ / ρ in parentheses is a value for X-rays generated at an acceleration voltage of 80 keV.

  There is no particular limitation on the thickness of the front wall and the rear wall in the direction in which X-rays are transmitted, but both the front wall and the rear wall are preferably 1 to 20 mm, and more preferably 5 to 15 mm. If the thickness exceeds 20 mm, X-rays that pass through the analysis mold are not sufficient, and a transmission X-ray image sufficient to analyze the solidification state of the molten metal cannot be obtained. Therefore, it is preferable that the thickness of the front wall and the back wall is thin, but less than 1 mm is not preferable because the strength for holding the molten metal is insufficient. In addition, it is preferable that the thickness of a front wall and a back wall is uniform.

  The analysis mold has a cavity filled with the molten metal and solidifies the molten metal in a direction substantially perpendicular to the direction through which X-rays pass. In other words, in the analysis mold, solidification in the X-ray transmission direction is suppressed. With this configuration, it is possible to two-dimensionally analyze the solidified state of the molten metal from the transmitted X-ray image. The analysis mold may include a front wall facing the X-ray irradiation unit, a back wall facing the X-ray detection unit, and a side wall that divides the cavity together with the front wall and the back wall. At this time, by making the thermal conductivity of the front wall and the rear wall lower than the thermal conductivity of the side walls, solidification in the X-ray transmission direction is effectively suppressed. Specifically, it is preferable to use front and rear walls made of a heat insulating material, and metal side walls made of copper, copper alloy, aluminum, aluminum alloy, or the like having high thermal conductivity among metals. As the heat insulating material, graphite or calcium silicate that easily transmits X-rays can be used. Alternatively, the side wall may be forcibly cooled to promote solidification of the molten metal in a direction substantially perpendicular to the direction through which X-rays pass. At this time, it is more effective if the side wall is made of a material having high thermal conductivity.

  Further, the cavity of the analysis mold is preferably 3 to 20 mm, more preferably 5 to 15 mm, in the direction in which X-rays are transmitted. If it is less than 3 mm, solidification in the X-ray transmission direction tends to be dominant, and it is not suitable for observing the solidification state. On the other hand, if it exceeds 20 mm, X-rays that pass through the analysis mold are not sufficient, and a transmission X-ray image sufficient for analyzing the solidification state of the molten metal cannot be obtained, which is not preferable. Note that the thickness of the cavity is preferably uniform.

  The analysis mold may further include a cooling means for cooling the side wall as described above, a temperature measuring means for measuring the temperature of the molten metal, and the like. By measuring the temperature at a predetermined position with the temperature measuring means, the solid phase ratio at that position can be calculated and compared with a transmission X-ray image.

  The X-ray detection unit is installed on the opposite side of the X-ray irradiation unit with the analysis template interposed therebetween, and detects X-rays transmitted through the analysis template as an image. A specific example of the X-ray detection means is an image intensifier (II). I. I. It is possible to detect and amplify even weak light and visualize it as an image with high contrast. Furthermore, the X-ray detection means may include an imaging device that images the detected transmitted X-ray image intermittently or continuously.

  It is possible to analyze the solidification state of the molten metal from the transmitted X-ray image detected by the X-ray detection means. As described above, when solidification progresses and there are many solid phases in the molten metal, X-rays are hardly transmitted. That is, the X-ray transmittance differs between the solid phase and the liquid phase. Therefore, the solidification state of the molten metal can be analyzed from the brightness of the transmitted X-ray image. Specifically, since the solid-liquid interface is known from the contrast of the transmission X-ray image of the entire analysis mold, the solidification process can be observed by continuously analyzing the transmission X-ray image. In addition to the contrast between the solid phase and the liquid phase, the contrast between the metal and the gas phase can be clearly obtained, so that it is possible to directly observe the generation behavior of the cast hole. Therefore, the casting analysis apparatus of the present invention is suitable for designing a casting plan.

Furthermore, it is preferable to provide a brightness calculation means for calculating the brightness from at least a part of the transmitted X-ray image obtained by the X-ray detection means. In order to quantify the solidification state of the molten metal by the brightness calculation means, for example, X-rays transmitted through the analysis template may be received with M bits (bit: M is an integer) to form an image. Alternatively, if the transmitted X-ray image is analog data, it may be converted into digital data of M bits (bit: M is an integer). Thus, the brightness is expressed in ^2M gradation, and the larger the value, the brighter. The value of M is preferably 10 or more and 16 or less. If it is less than 10 bits, the contrast between the solid phase and the liquid phase may not be clearly obtained. Here, the contrast suitable for analyzing the solidified state of the molten metal is that the brightness difference before and after eutectic phase crystallization is 2 ^M−8 or more in M bits, and further 1.25 × 2 ^M−8 or more ( It is good that it is 16 or more, more preferably 20 or more in 12 bits. This is because if the brightness difference before and after eutectic phase crystallization is less than 2 ^M−8 , the brightness difference may be unrecognizable because it is buried in brightness “fluctuation” that occurs when receiving transmitted X-rays. In addition, when the value of M is large, accurate data conforming to the transmitted X-ray image can be obtained. However, if the value exceeds 16 bits, the obtained data size becomes large, which is not preferable. Note that by performing digital processing on the transmitted X-rays, casting analysis using various software becomes possible.

  Furthermore, it is preferable to include a determination unit that determines the cleanliness of the molten metal when the lightness calculated by the lightness calculation unit exceeds a threshold value. The cleanliness of the molten metal determined by the determination means is the amount of gas contained in the molten metal. When dissolved gas exists in the molten metal, it is generated as bubbles during the progress of solidification. A metal melt with a large amount of bubbles, that is, a large amount of dissolved gas, is not suitable for casting. When bubbles are generated in the liquid phase, the brightness of the transmitted X-ray image is increased, so that the purity of the molten metal can be determined. Even if shrinkage cavities are generated due to phase transformation from the liquid phase to the solid phase, the brightness of the transmitted X-ray image is increased. However, with the casting analysis apparatus of the present invention, by observing a transmission X-ray image over time, whether the void that caused the increase in brightness is a bubble generated in the liquid phase, It is easy to determine whether there is.

  Further, by using the casting analysis apparatus of the present invention, it is possible to analyze the solidification state inside the mold (manufacturing mold) actually used at the time of casting. Specifically, the cross section perpendicular to the X-ray transmission direction of the analysis mold is set to the same shape as the cross section of the analysis site that is a part of the production mold for manufacturing the casting. As described above, the analysis mold is suppressed from solidifying in the X-ray transmission direction. Therefore, in the analysis mold, the solidification process at the analysis site is reproduced, and the solidification state of the molten metal inside the production mold can be analyzed from the brightness of the transmitted X-ray image obtained by the X-ray detection means. . Therefore, when it is desired to analyze the solidification state of the entire production mold, a plurality of analysis molds having a cross-sectional shape corresponding to each position of the production mold are produced. By preparing a plurality of analysis molds and analyzing the solidification state of the molten metal using the casting analysis apparatus of the present invention, it is possible to capture the solidification state in the production mold three-dimensionally.

[Casting analysis method]
The casting analysis method of the present invention is a casting analysis method for analyzing a molten metal filled in an analysis mold by X-rays, and mainly includes a pouring step, an X-ray irradiation step, a solidification step, an X-ray detection step, and a solidification step. Analysis process.

  The pouring step is a step of pouring molten metal into the analysis mold. The analysis template is as described above. What is necessary is just to select suitably conditions for pouring, such as molten metal temperature and pouring speed.

  The X-ray irradiation step is a step of irradiating the analysis template with X-rays. X-ray irradiation may be started at least by the end of the pouring process or immediately after the end. However, when it is desired to observe the hot water flow when the molten metal is filled in the analysis mold, it may be performed in parallel with the pouring step.

  The solidification step is a step of solidifying the molten metal in a direction substantially perpendicular to the direction through which X-rays pass in parallel with the X-ray irradiation step. By using the analysis mold already described, the molten metal after pouring is solidified in a direction substantially orthogonal to the direction through which X-rays pass.

  The X-ray detection step is a step of detecting, as an image, X-rays that have passed through the analysis template in parallel with the X-ray irradiation step. In the solidification analysis step, the solidification state of the molten metal is analyzed from at least the brightness difference caused by the difference in X-ray transmittance between the solid phase and the liquid phase in the transmitted X-ray image obtained by the X-ray detection means. It is a process. The X-ray detection process and the solidification analysis process are as already described in the section of “Casting analysis apparatus”.

  The casting analysis method of the present invention further includes a brightness calculation step for calculating brightness from at least a part of the transmitted X-ray image, and the cleanliness of the molten metal when the brightness calculated by the brightness calculation means exceeds a threshold value. A determination step for determining may be included. The brightness calculation step and the determination step are as already described in the section of “Casting analysis device”.

  As mentioned above, although embodiment of the casting analysis apparatus and casting analysis method of this invention was described, this invention is not limited to the said embodiment. The present invention can be implemented in various forms without departing from the gist of the present invention, with modifications and improvements that can be made by those skilled in the art.

  Hereinafter, the present invention will be specifically described with reference to examples of the casting analysis apparatus and the casting analysis method of the present invention.

FIG. 1 is a schematic diagram of a casting analysis apparatus. The casting analysis apparatus includes an X-ray generator 1, an analysis mold 2, an image intensifier (II) 3, and a television camera 4. As the X-ray generator 1, HMX225 manufactured by X-Tek (USA), I.D. I. As TH 3, TH49432QX H681 VR33 manufactured by Thales Electronics Devices (France) was used. X-ray generator 1 and I.I. I. 3 are arranged opposite to each other with the analysis mold 2 interposed therebetween. In other words, the X-rays irradiated from the X-ray generator 1 pass through the analysis template 2 and I.I. I. 3 is input. The TV camera 4 is an I.I. I. In order to visualize the optical image of the transmitted X-ray of the analysis template 2 converted and output by the I. 3 on the output side. Image data of the TV camera 4 is a digital data of 12bit, X-rays transmitted through the analysis mold 2 is represented by the lightness of the 4096 gradations ^{(= 2 12} gradations). Hereinafter, the configuration of the analysis mold 2 will be described.

  2 and 3 are cross-sectional views of the central portion of the analysis mold 2. FIG. 2 shows a cross section perpendicular to the direction through which X-rays pass. FIG. 3 shows a cross section parallel to the direction through which X-rays pass. The analysis mold 2 includes a front wall 21 facing the X-ray generator 1, I.V. I. 3 and a side wall 22 that defines the cavity 20 together with the front wall 21 and the back wall 23. Both the front wall 21 and the rear wall 23 are 110 mm × 100 mm × 10 mm graphite plates. The side wall 22 is formed by cutting out a central portion of a 110 mm × 100 mm × 10 mm copper plate in accordance with the shape of the side surface 22s of the cavity 20 and forming a gate 20a communicating with the central portion. Furthermore, a flow path 22 a through which cooling water circulates is formed at the peripheral edge of the side wall 22. The front wall 21, the side wall 22, and the back wall 23 are laminated and fixed in order in the direction in which X-rays are transmitted. That is, the opposing surfaces of the front wall 21 and the back wall 23 become the front surface 21 s and the back surface 23 s that define the cavity 20. As can be seen from the dimensions of the front wall 21, the side wall 22, and the back wall 23, the analysis mold 2 has a cavity 20 with a thickness T = 10 mm and a thickness t = 10 mm with respect to the direction in which X-rays are transmitted. A front wall 21 and a back wall 23 are provided. The maximum width of the cavity 20 was 90 mm, and the maximum height of the cavity 20 (including the gate 20a) was 90 mm.

  The casting analysis of the aluminum alloy was performed using the casting analysis apparatus described above. AC4C and ADC12 (both JIS standards) were prepared as aluminum alloys.

  First, a molten aluminum alloy (ADC12: 750 ° C.) was poured into the analysis mold 2. When the cavity 20 was filled with the molten metal, the X-ray generator 1 (X-ray tube voltage 80 keV) was activated, and X-ray irradiation was started on the analysis mold 2. At the same time, I.I. I. 3 and the TV camera 4 were activated. Further, the cooling water was circulated through the flow path 22a to promote the solidification of the molten metal filled in the cavity 20 in one direction. I. I. The transmitted X-rays input to 3 were converted into an optical image, and this optical image was continuously recorded by the television camera 4.

  FIG. 4 shows transmitted X-ray images continuously recorded by the television camera 4. Note that the transmission X-ray image shown in FIG. 4 is a still image at a certain point (in the middle of coagulation) of the transmission X-ray image continuously recorded along with the progress of coagulation. In the image of the television camera 4, as indicated by an arrow in FIG. 4, a dark region (including a large amount of solid phase) spreads from the side surface 22 s of the cavity 20 toward the center of the cavity 20 over time. Observed visually. That is, it was observed that the solidification interface moved by the above casting analysis apparatus. In FIG. 4, a dark region is seen on the side surface 22s side of the cavity 20, and the brighter the closer to the center. The brightest part in the center shows the presence of the gas phase and is the final solidified part where the cast hole is generated.

  In the above casting analysis apparatus, the same transmission X-ray image is obtained by changing the thickness t of the front wall 21 and the rear wall 23 in the direction in which X-rays are transmitted or the thickness T of the cavity 20 in the direction of transmission of X-rays. When t was 20 mm or less or T was 20 mm or less, the movement of the solidification interface could be easily observed visually. When t was 15 mm or less or T was 15 mm or less, an image equivalent to the transmission X-ray image shown in FIG. 4 obtained at t = 10 mm and T = 10 mm was obtained.

  Next, the brightness of a predetermined region (5 mm × 5 mm in terms of cavity size) of the obtained transmission X-ray image was calculated. Free software ImageJ manufactured by the National Institutes of Health was used to calculate the brightness of the transmitted X-ray image. The brightness with respect to the solid phase ratio is shown in FIG. The solid phase ratio was calculated from the measured value obtained by measuring the temperature of the molten metal in which solidification is in progress at the position corresponding to the site where the brightness was calculated. A similar analysis was performed for AC4C. The results are shown in FIG. Immediately after the start of cooling (solid phase ratio = 0), the brightness of the transmitted X-ray image was high because the liquid phase was almost liquid. However, the brightness of all the aluminum alloys gradually decreased as the solid phase ratio approached 1. Since ADC12 contains Cu and Zn, the brightness of the transmitted X-ray image was generally lower than that of AC4C.

  FIG. 6 is a graph showing the X-ray intensity ratio with respect to the solid phase ratio of ADC12 and AC4C. The X-ray intensity ratio on the vertical axis was obtained by calculating the transmitted X-ray dose from the known X-ray absorption rate corresponding to the type and amount of the crystallized substance with respect to the solid phase rate, assuming that the X-ray is monochromatic X-ray light. Is. For example, in AC4C, as shown in the schematic diagram of the metal structure shown in the graph of FIG. 6, after the primary crystal Al crystallizes in the liquid phase, the Al—Si eutectic phase crystallizes and completely solidifies. Since the primary crystal Al and the Al—Si eutectic phase have different densities, the transmitted X-ray dose greatly decreases when the Al—Si eutectic phase begins to crystallize. That is, the crystallization of the eutectic phase starts at a solidification rate of about 0.5 where the X-ray intensity ratio is greatly reduced. Further, in ADC 12, the amount of primary Al crystallized is smaller than that of AC4C. Therefore, in the ADC 12, a decrease in the transmitted X-ray dose indicating the start of crystallization of the eutectic phase is observed at a solid phase ratio of about 0.1.

  Here, when FIG. 5 and FIG. 6 are compared, they are almost the same. That is, the analysis using the casting analysis apparatus of the present invention was a highly reliable analysis that almost coincided with the theoretical value.

  Next, the molten metal (ADC12) was solidified using the analysis mold 2 in which the thickness of the front wall 21 and the back wall 23 was t = 24 mm, and the same analysis was performed. The results are shown in FIG. For comparison, FIG. 7 shows the lightness with respect to the solid phase ratio of ADC 12 as in FIG. 5 as “t = 10 mm”. As can be seen from FIG. 7, at t = 24, the brightness difference before and after the eutectic phase was crystallized was about 10. On the other hand, at t = 10, the brightness difference before and after the eutectic phase was crystallized exceeded 20. Moreover, the brightness was high overall as compared with t = 24. That is, it was found that the thinner the thickness t of the front wall and the rear wall in the direction in which X-rays pass, the easier it is to observe the solidified state of the molten metal based on the brightness of the transmitted X-ray image.

It is the schematic of a casting analysis apparatus. It is sectional drawing of the center part of the casting_mold | template for analysis, Comprising: The cross section of a perpendicular | vertical direction is shown with respect to the direction which X-ray permeate | transmits. It is sectional drawing of the center part of the casting_mold | template for analysis, Comprising: A cross section parallel to the direction which X-ray permeate | transmits is shown. It is the transmission X-ray image obtained by the analysis using a casting analyzer. It is a graph which shows the brightness (measured value) of the transmission X-ray image with respect to the solid-phase rate (calculated from temperature measurement) of ADC12 and AC4C. It is a graph which shows the X-ray-intensity ratio (calculated value) with respect to the solid-phase rate of ADC12 and AC4C. It is a graph which shows the lightness (measured value) of the transmission X-ray image with respect to the solid-phase rate (calculated from temperature measurement) of ADC12.

Explanation of symbols

1: X-ray generator (X-ray irradiation means)
2: Analysis mold 20: Cavity 21: Front wall 22: Side wall 23: Back wall 3: Image intensifier (X-ray detection means)

Claims (11)

An X-ray irradiation means having an X-ray source;
An analysis mold for solidifying the molten metal in a direction substantially perpendicular to the direction of transmission of X-rays having a cavity through which X-rays irradiated from the X-ray irradiation means are transmitted and filled with the molten metal;
X-ray detection means for detecting as an image X-rays installed on the opposite side of the X-ray irradiation means across the analysis template, and transmitted through the analysis template;
And analyzing the solidification state of the molten metal from the difference in brightness caused by the difference in the X-ray transmittance between the solid phase and the liquid phase of the transmitted X-ray image obtained by the X-ray detection means. Characteristic casting analysis device.   The casting analysis apparatus according to claim 1, further comprising brightness calculation means for calculating brightness from at least a part of the transmitted X-ray image obtained by the X-ray detection means.   Furthermore, the casting analysis apparatus of Claim 2 provided with the determination means which determines the cleanliness of the said molten metal when the brightness calculated by the said brightness calculation means exceeds a threshold value. The analysis template has a front wall facing the X-ray irradiation means and a back wall facing the X-ray detection means, and the front wall and the back wall absorb mass with respect to X-rays generated at an acceleration voltage of 80 keV. The casting analysis apparatus according to claim 1, wherein the casting analysis apparatus is made of a material having a coefficient of 0.25 cm ² / g or less.   The analysis mold has a front wall facing the X-ray irradiating means and a back wall facing the X-ray detecting means, and the thickness of the front wall and the back wall in the direction in which X-rays pass is 1 to 1. The casting analysis apparatus according to claim 1, which is 20 mm.   The casting analysis apparatus according to claim 1, wherein the cavity of the analysis mold has a thickness of 3 to 20 mm in a direction in which X-rays are transmitted.   The analysis mold includes a front wall facing the X-ray irradiation means, a back wall facing the X-ray detection means, and a side wall that defines the cavity together with the front wall and the back wall. The casting analysis apparatus according to claim 1, wherein the thermal conductivity of the wall and the back wall is lower than the thermal conductivity of the side wall.   The casting analysis apparatus according to claim 1, wherein the molten metal is an aluminum alloy or a magnesium alloy.   The casting analysis apparatus according to claim 1, wherein the analysis mold includes temperature measuring means for measuring a temperature of the molten metal.   The cross section perpendicular to the X-ray transmission direction of the analysis mold has the same shape as the cross section of the analysis site that is a part of the production mold for manufacturing the casting, and the transmission obtained by the X-ray detection means. The casting analysis apparatus according to claim 1, wherein the solidification state of the molten metal at the analysis site is analyzed from the brightness of an X-ray image. A casting analysis method for analyzing a molten metal filled in an analysis mold by X-ray,
A pouring step of pouring the molten metal into the analysis mold;
An X-ray irradiation step of irradiating the analysis mold with X-rays;
A solidification step of solidifying the molten metal filled in the analysis mold in a direction substantially orthogonal to a direction through which X-rays pass in parallel with the X-ray irradiation step;
An X-ray detection step for detecting, as an image, X-rays transmitted through the analysis template in parallel with the X-ray irradiation step;
A solidification analysis step of analyzing a solidification state of the molten metal from a difference in brightness caused by a difference in X-ray transmittance between at least a solid phase and a liquid phase of a transmission X-ray image obtained in the X-ray detection step;
A casting analysis method comprising: