Search Sites

Tetsu-to-Hagané Advance Publication

ISIJ International
belloff

Grid List Abstracts

ONLINE ISSN: 1883-2954
PRINT ISSN: 0021-1575
Publisher: The Iron and Steel Institute of Japan

Backnumber

  1. Vol. 110 (2024)

  2. Vol. 109 (2023)

  3. Vol. 108 (2022)

  4. Vol. 107 (2021)

  5. Vol. 106 (2020)

  6. Vol. 105 (2019)

  7. Vol. 104 (2018)

  8. Vol. 103 (2017)

  9. Vol. 102 (2016)

  10. Vol. 101 (2015)

  11. Vol. 100 (2014)

  12. Vol. 99 (2013)

  13. Vol. 98 (2012)

  14. Vol. 97 (2011)

  15. Vol. 96 (2010)

  16. Vol. 95 (2009)

  17. Vol. 94 (2008)

  18. Vol. 93 (2007)

  19. Vol. 92 (2006)

  20. Vol. 91 (2005)

  21. Vol. 90 (2004)

  22. Vol. 89 (2003)

  23. Vol. 88 (2002)

  24. Vol. 87 (2001)

  25. Vol. 86 (2000)

  26. Vol. 85 (1999)

  27. Vol. 84 (1998)

  28. Vol. 83 (1997)

  29. Vol. 82 (1996)

  30. Vol. 81 (1995)

  31. Vol. 80 (1994)

  32. Vol. 79 (1993)

  33. Vol. 78 (1992)

  34. Vol. 77 (1991)

  35. Vol. 76 (1990)

  36. Vol. 75 (1989)

  37. Vol. 74 (1988)

  38. Vol. 73 (1987)

  39. Vol. 72 (1986)

  40. Vol. 71 (1985)

  41. Vol. 70 (1984)

  42. Vol. 69 (1983)

  43. Vol. 68 (1982)

  44. Vol. 67 (1981)

  45. Vol. 66 (1980)

  46. Vol. 65 (1979)

  47. Vol. 64 (1978)

  48. Vol. 63 (1977)

  49. Vol. 62 (1976)

  50. Vol. 61 (1975)

  51. Vol. 60 (1974)

  52. Vol. 59 (1973)

  53. Vol. 58 (1972)

  54. Vol. 57 (1971)

  55. Vol. 56 (1970)

  56. Vol. 55 (1969)

  57. Vol. 54 (1968)

  58. Vol. 53 (1967)

  59. Vol. 52 (1966)

  60. Vol. 51 (1965)

  61. Vol. 50 (1964)

  62. Vol. 49 (1963)

  63. Vol. 48 (1962)

  64. Vol. 47 (1961)

  65. Vol. 46 (1960)

  66. Vol. 45 (1959)

  67. Vol. 44 (1958)

  68. Vol. 43 (1957)

  69. Vol. 42 (1956)

  70. Vol. 41 (1955)

Tetsu-to-Hagané Advance Publication

Evaluation of Corrosion on Steel Surface Using Image Processing

Takahiro Igarashi, Yu Sugawara, Kyohei Otani, Takahito Aoyama

Abstract

Using two types of image processing techniques without machine learning, edge extraction processing and keypoint extraction processing, progressively corroded regions under the rust layer from images of corroded steel surfaces was extracted. We found that there was a relatively good correlation between the keypoint strength obtained from the keypoint extraction processing for HSL transformed and histogram flattened corroded surface images and the corrosion depth after rust removal.

Bookmark

Share it with SNS

Article Title

Evaluation of Corrosion on Steel Surface Using Image Processing

Properties at Corrosion Sites Formed on Pure Iron during Wet-dry Cycling Test and on Steel during Exposure Test

Soshiro Yamazaki, Fuka Kawamura, Koki Saito, Makoto Chiba

Abstract

Steels are widely used as a structural material for infrastructure, such as bridges. However, some of bridges built in Japan, have passed more than 50 years, since construction. Thus, these bridges will need to be reconstruction, because atmospheric corrosion of these materials will occur in this condition. However, there are numerous bridges in Japan, and reconstruction of these bridges would need much cost. Therefore, it is necessary to establish the technique for selection of the bridges with severe damage by atmospheric corrosion. To establish a new non-destructive and non-contact techniques for identifying the sites of atmospheric corrosion occurred in steel, used as structural materials for bridges, the relation between corrosion site and color of corrosion product, surface morphology or distribution of surface potential of the pure iron and steel after corrosion test were evaluated.

Bookmark

Share it with SNS

Article Title

Properties at Corrosion Sites Formed on Pure Iron during Wet-dry Cycling Test and on Steel during Exposure Test

Effect of Manganese on Cryogenic Toughness of 7% Nickel-added Steels with Intermediate Heat Treatment

Yuya Sato, Shunichi Tachibana, Takeshi Nishiyama, Rikiya Madanbashi, Osamu Umezawa, Tetsuya Tagawa

Abstract

The effect of the manganese content of 7 % nickel-added steel on cryogenic toughness was investigated. When Charpy absorbed energy was investigated in the steels with wide range manganese content from 0.05 % to 2.16 %, the absorbed energy at −196 °C increased with a decrease of manganese content. The two steels with manganese contents of 0.2 % and 0.8 % were selected for use in a more detailed investigation regarding the dependence of toughness at −196 ℃ on the intermediate heat treatment temperature, fracture behaviors and the retained austenite. Although the 0.2 % manganese steel stably exhibited a high absorbed energy at −196 ℃ at all intermediate heat treatment temperatures examined in this work, it was necessary to select an appropriate intermediate heat treatment temperature for the 0.8 % manganese steel in order to achieve high absorbed energy at −196 ℃. The total amount of the retained austenite and the size and the nickel content locally segregated into an identical retained austenite were quantified by using XRD and SEM/EDS, and the characteristics of the retained austenite in the steels with low manganese alloy designs were investigated. The cleavage-type brittle fracture that appeared in some specimens was discussed from the viewpoint of the stability of retained austenite.

Bookmark

Share it with SNS

Article Title

Effect of Manganese on Cryogenic Toughness of 7% Nickel-added Steels with Intermediate Heat Treatment

Effect of BN Surface Segregation on Coatability in Hot-dip Galvanizing of B-added Steel

Daisuke Tahara, Katsuya Hoshino, Shoichiro Taira

Abstract

Boron (B) is frequently used as additives to improve the hardenability of advanced high strength steel. It has been reported that B in steel reacts with atmospheric N2 during annealing at low oxygen potential (low dew point) to form boron nitride (BN) by the thermodynamical calculation. In this study, the effect of BN formation on the steel surface on the coatability during hot-dip galvanizing was investigated, experimentally. B-free specimens and specimens containing 15 or 30 ppm B were annealed at various temperature and dew point, and then hot-dip galvanized. The annealed specimens were also prepared and analyzed with GD-OES, XPS, SEM-EDX and TEM-EELS to investigate the oxide and nitride formation on the steel surface during annealing. As results, coatability deteriorated as the amount of B in steel and the annealing temperature increase, and as the dew point decrease. These trends were not correlated with the amount of oxide but the amount of BN formation, suggesting that BN formation deteriorated the coatability. The surface and cross-sectional analysis revealed that BN formed around the oxide to cover the steel surface. This would lead the deterioration of the coatability because most of the steel surface was covered with BN as well as oxide, which are known to have low wettability with molten Zn.

Bookmark

Share it with SNS

Article Title

Effect of BN Surface Segregation on Coatability in Hot-dip Galvanizing of B-added Steel

Conveyor Belt Vibration Analysis Using High-Speed Video Images

Feiyue Wang, Kohei Shimasaki, Takashi Fujimoto, Shaopeng Hu, Idaku Ishii, Ai Matsumoto, Yoshiyuki Umegaki, Tomohiko Ito

Abstract

This study proposes a novel video-based conveyor monitoring method that can estimate distances between belt-supporting rollers by analyzing belt vibration responses in high-frame-rate (HFR) images. Focusing on the fact that the vibration components of a belt include frequencies inversely proportional to the distance between its ends, roller-to-roller distances that correspond to the state of contact between a belt and rollers are estimated by HFR-video-based analysis that can detect vibration peak frequencies at multiple belt positions without directly observing them captured in images. Its effectiveness was verified by conducting a wide-area monitoring test of a material handing conveyor in ironworks for roller-to-roller distance estimation with vibration frequency analysis at multiple points on its several-tens-of-meters belt in 9344×600 images captured at 300 fps.

Readers Who Read This Article Also Read

Bookmark

Share it with SNS

Article Title

Conveyor Belt Vibration Analysis Using High-Speed Video Images

Microstructural Evolution and Quantitative Evaluation of Precipitates during Long-term Creep of KA-SUS304J1HTB

Hayato Tokunaga, Shengde Zhang, Kenji Kako, Masatsugu Yaguchi, Koji Tamura, Yusuke Minami

Abstract

This paper presents microstructural evolution and quantitative evaluation of precipitates during long-term creep of KA-SUS304J1HTB steel. Thermal aging and creep tests were conducted on a virgin material at 600 ~ 700 °C, for up to 26000 h, and the microstructures in grip and gage sections of creep ruptured specimens were observed by scanning and transmission electron microscopy including chemical analysis techniques. The effects of temperature and time on the growth of the σ phase and the Cu phase were quantitatively evaluated. Mean particle size of the Cu phase in the grain was increased with aging time by the volume diffusion control theory, and the activation energy for the Cu phase growth was calculated. Mean particle size of the σ phase and the Cu phase in grips were comparable to those in gage section, indicating that stress has little effect on both parameters. On the other hand, the average of the maximum particle size in the observation area and area fraction of the σ phase were larger in the gage section than those in the grips due to the effect of stress.

Readers Who Read This Article Also Read

Bookmark

Share it with SNS

Article Title

Microstructural Evolution and Quantitative Evaluation of Precipitates during Long-term Creep of KA-SUS304J1HTB

Color Tone of Corrosion Products and Estimation of Rust Composition by Image Processing

Kenta Fujihashi, Wataru Oshikawa

Abstract

Appropriate maintenance and maintenance of infrastructures that has been used for a long time is required because there is the concern that safety will deteriorate due to atmospheric corrosion. However, the cost of maintenance and management is also increasing, and there is required to save labor and improve efficiency of maintenance and management. Therefore, the purpose of this study was to easily estimate the rust composition by the image processing of image of steel surface corroded by the outdoor exposure test. The outdoor exposure test was conducted in Choshi City and those conditions were open exposure and shelter exposure for 2.5 years. The compositions of those corrosion products measured by X-ray diffraction. Exposed test pieces were photographed RAW with the digital camera. Those photographs were developed and trimmed. The obtained images were converted from RGB images to La*b* and LCh images. The histograms of hue were fitted to the Gaussian function to determine the peak position and the spread of the histogram. As a result, it was indicated that the peak position shown in the histogram of hue shifted to the low-angle side due to the increase in FeFe2O4. In addition, it was indicated that the composition ratio of α-FeOOH, β-FeOOH, γ-FeOOH and FeFe2O4 can be estimated by the shape, spread and peak position of the histogram of hue. As shown in the graphical abstract, the composition ratio of the corrosion products measured by RIR method and estimated by image processing was in good agreement.

Bookmark

Share it with SNS

Article Title

Color Tone of Corrosion Products and Estimation of Rust Composition by Image Processing

Effect of Re-ignition Method on Sinter Yield Through Improving Carbon Combustion Ratio at Upper Layer of Sinter Packed Bed

Masaru Matsumura, Ryota Kosugi, Yuichiro Yamamoto, Junji Nagata, Kenichi Higuchi

Abstract

Conventionally, it has been known that the product yield of the upper part of the sintering layer is extremely low, because of the heat loss caused by transferring heat toward the space above sintering layer, and of the large amount of unburned carbon in upper sintering layer.

Bookmark

Share it with SNS

Article Title

Effect of Re-ignition Method on Sinter Yield Through Improving Carbon Combustion Ratio at Upper Layer of Sinter Packed Bed

Density and Surface Tension Measurement of Fe-Ga Melts Using Electromagnetic Levitation Technique

Masayoshi Adachi, Hideo Higashi, Ikuma Nagakusa, Toru Kawamata, Tsuyoshi Kumagai, Tsuguo Fukuda, Shigeru Suzuki, Hiroyuki Fukuyama

Abstract

Fe-Ga alloys are expected as a magnetostrictive material. Currently, Fe-Ga single crystals have been fabricated by the Czochralski method. Thermophysical properties of the Fe-Ga melt are necessary for the improvement of the crystal growth technique, however, these have not measured to date. The aim of this study was therefore to measure the density and surface tension of Fe-Ga melts using electromagnetic levitation technique. It is possible to measure thermophysical property of sample melts at undercooling condition using the electromagnetic levitation method. The density and surface tension of the Fe-Ga decreased with increasing temperature including supercooling temperature region. The molar volume of the Fe-Ga melt is smaller than the molar volume calculated assuming ideal solution. The surface tension of the Fe-Ga melt was in good agreement with the surface tension calculated from Butler model.

Bookmark

Share it with SNS

Article Title

Density and Surface Tension Measurement of Fe-Ga Melts Using Electromagnetic Levitation Technique

Application of Admittance Analysis for Corrosion Rate Evaluation of Carbon Steel with Rust Layer in Electrochemical Impedance Spectroscopy

Yusaku Akimoto, Yoshinao Hoshi

Abstract

This paper describes an evaluation method for corrosion rate of carbon steel covered with rust layer by admittance analysis in electrochemical impedance spectroscopy. The polarization resistance, Rp, is often estimated from the impedance spectrum of carbon steel to determine the corrosion rate. The Rp can be determined from the impedance spectrum when the low frequency impedance is converted to the real axis on the Nyquist diagram. Because the impedance spectrum of carbon steel covered with rust layer often describes a part of loop in the low frequency range, it is difficult to determine the Rp by extrapolating the low frequency impedance to the real axis. In the present study, an admittance analysis was employed to determine the Rp from the admittance spectrum of carbon steel covered with rust layer. The admittance is plotted as the reciprocal of impedance on the complex plane. In this case, the Rp can be determined from the admittance spectrum when the low frequency admittance is converged to the real axis. The admittance spectrum of carbon steel with rust layer indicated that the low frequency admittance was converted to the real axis, namely, the Rp could be determined from the admittance spectrum. The corrosion rate of carbon steel with rust layer could be estimated from the Rp by admittance analysis, demonstrating that the value was corelated to that estimated from corrosion loss. The impedance and admittance simulations were performed using an equivalent circuit to discuss the time constant observed in the low frequency range.

Bookmark

Share it with SNS

Article Title

Application of Admittance Analysis for Corrosion Rate Evaluation of Carbon Steel with Rust Layer in Electrochemical Impedance Spectroscopy

Identification of Structural Damage by Rate of Change of Non-Dimensional Displacement of Beams Subject to Moving Loads

Aoi Koga, Taisei Uchida, Kenji Sasaki, Idaku Ishii, Kohei Shimasaki, Hiroshi Matsuda

Abstract

This study aims to identify structural damage in beams subjected to moving loads using the rate of change of the time history response of non-dimensional displacements. We analyze the time response of displacements of beams subjected to moving loads using the finite element method. The structural damage of the beam is simulated by changing the cross-sectional shape of the beam in a part of the section. The analysis results show that damage cannot be identified by the displacement time-history response alone but can be identified using the change rate of the displacement time-history response. Furthermore, it is shown that damage can be identified independent of the magnitude and velocity of the moving load by using the rate of change of the non-dimensional displacement time history response. These results suggest that our method can be used to identify damage in actual structures subjected to moving loads.

Bookmark

Share it with SNS

Article Title

Identification of Structural Damage by Rate of Change of Non-Dimensional Displacement of Beams Subject to Moving Loads

Origin of Serrated Markings on the Hydrogen Related Quasi-cleavage Fracturein Low-carbon Steel with Ferrite Microstructure

Kazuho Okada, Akinobu Shibata, Hisashi Matsumiya, Nobuhiro Tsuji

Abstract

A typical hydrogen-related transgranular fracture, namely quasi-cleavage fracture, is usually accompanied by serrated markings on the resultant fracture surfaces in steels with body-centered cubic phases. The present paper investigated the microscopic three-dimensional morphology and crystallographic feature of serrated markings in a 2Mn-0.1C steel mainly composed of ferrite microstructure. The serrated markings corresponded to the corners of the step-like morphologies which consisted of microscopic {011} facets whose longitudinal directions were almost parallel to <011> or <211> direction. In addition, the microscopic {011} quasi-cleavage facets had the largest inclination angle from tensile axis among six crystallographically equivalent {011} planes, suggesting that resolved normal stress imposed on the {011} plane is an important factor for the hydrogen-related quasi-cleavage fracture. We propose that not only the slip deformation enhanced by hydrogen but also the coalescence of vacancies/voids induced by hydrogen-enhanced plastic deformation should be considered for understanding the mechanism of the hydrogen-related quasi-cleavage fracture along the {011} planes.

Bookmark

Share it with SNS

Article Title

Origin of Serrated Markings on the Hydrogen Related Quasi-cleavage Fracturein Low-carbon Steel with Ferrite Microstructure

Development of a Method for Estimating Stress-strain Relationships Based on the Results of Indentation Tests that Eliminated the Size Effect Attributed to Ultra-small Loads

Takumi Sakamaki, Keisuke Nishimoto, Masaki Nishimura, Yoshiteru Aoyagi

Abstract

For small samples for which tensile tests cannot be conducted, methods have been developed to estimate stress-strain relationships using indentation tests and analysis models that simulate these tests. However, precise modeling of factors such as wear at the indenter tip and friction coefficients between the indenter and material is challenging. A few examples are applied to small regions, such as single crystal grains, using small loads. In this study, we developed a method to estimate stress-strain relationships based on the work-hardening law from load-displacement curves and hardness measured by pyramidal indentation tests. Using the presented method, we evaluated the stress-strain relationships from nanoindentation test results obtained under a load of five mN and results from micro-Vickers hardness tests conducted under a load of 10 N. While micro-Vickers test results estimated curves similar to tensile test results, the estimation accuracy decreased for nanoindentation tests with lower loads. This reduction in accuracy is attributed to the size effect of hardness, which occurs under low-load conditions. To improve the estimation accuracy under low-load conditions, we determined correction coefficients to reduce the influence of the size effect by comparing the estimation results under both load conditions for ferritic single-phase materials fabricated within the compositional range of hypoeutectoid steel. As a result, it is now possible to estimate the stress-strain relationship using indentation tests from microregions, approaching the scale of single crystal grains, for materials within the compositional range of hypoeutectoid steel.

Bookmark

Share it with SNS

Article Title

Development of a Method for Estimating Stress-strain Relationships Based on the Results of Indentation Tests that Eliminated the Size Effect Attributed to Ultra-small Loads

Measurements of Carbon Content and Retained Austenite Volume Fraction in Steels by Neutron Bragg-edge Transmission Analysis at a Compact Neutron Source, AISTANS

Koichi Kino, Yo Tomota, Nagayasu Oshima

Abstract

Neutron Bragg-edge transmission analysis was performed at a newly constructed compact neutron source, AISTANS, for 30Mn-C austenitic steels and ferrite-bainite-retrained austenite (TR) steels, which had previously been measured at BL22, RADEN, in J-PARC MLF. Employing a newly developed 2D Li-glass neutron detector, Bragg-edge spectra were obtained at 1 kW electron-beam operation of AISTANS. The obtained profiles were analyzed using the RITS code. In 30Mn-C steels, the determined lattice parameters were found to show a linear dependence with carbon content, similarly to the results obtained at RADEN. In TR steels, Bragg-edge spectra obtained from three orthogonal directions were differently shaped each other stemmed from the texture. Reasonable fitting was obtained only in the cases in which the influence of texture was weak; the profile obtained along the rolling direction or averaged one of the three directional results.

Bookmark

Share it with SNS

Article Title

Measurements of Carbon Content and Retained Austenite Volume Fraction in Steels by Neutron Bragg-edge Transmission Analysis at a Compact Neutron Source, AISTANS

Active Structure Sensing Based on High-resolution Cameras

Banri Kishibe, Feiyue Wang, Kohei Shimasaki, Idaku Ishii, Hiroshi Matsuda

Abstract

This study proposes a novel approach to structural health monitoring through active structure sensing using a high-resolution camera for deflection distribution measurement under operational conditions. With the increasing the number of aging social and plant infrastructures, structure health monitoring becomes crucial for early detection of structural anomalies due to deterioration. Conventional contact sensors like strain gauges and accelerometers face challenges in installation and structural limitations, and confine frequent inspections to infrastructures under operation regulations and elevating inspection costs. This study introduces an active sensing method that captures the effects of load passage on deflection displacement around structural anomalies of infrastructures in operating with moving loads, and dimensionless deflection influence lines are defined as speed- and weight-invariant features in active structure sensing. Their effectiveness for structural anomaly detection is validated by showing dimensionless deflection influence lines when loads are moving on 3-m-length H section metal beams.

Bookmark

Share it with SNS

Article Title

Active Structure Sensing Based on High-resolution Cameras

Identification of Rusts Formed on Steels by Image Analysis with HSV Color Space

Hiroo Ishii, Masatoshi Sakairi

Abstract

Corrosion products formed on steel in various environments were identified with image analysis, Raman spectroscopy, and X-ray diffraction (XRD). The results of Raman spectroscopy showed that γ-FeOOH exhibits bright yellow color and β-FeOOH exhibits gray color. Main corrosion products composition formed on the steels by XRD analysis was γ-FeOOH. Using proper threshold of HSV color space, makes it possible to identify corrosion products formed on steel. Comparison of corrosiveness of exposed environments and formed corrosion products, α-FeOOH is preferentially formed in mild corrosive environments, while β-FeOOH was formed in severe corrosive environments.

Bookmark

Share it with SNS

Article Title

Identification of Rusts Formed on Steels by Image Analysis with HSV Color Space

Composition Analysis of Corrosion Products on Steel by Machine Learning of Optical Microscopic Images

Yuki Tsuji, Kota Hirasawa, Sunao Shoji, Yuichi Kitagawa, Yasuchika Hasegawa, Koji Fushimi

Abstract

Analysis of the corrosion distribution and composition of corrosion products on steel surfaces using supervised machine learning of optical microscopic images was investigated. The accuracy of the artificial intelligence in evaluating the composition of iron compound reference samples was affected by the illumination intensity and surface roughness during image capture. The evaluation accuracy was high for compounds with a wide distribution of R value such as Fe2O3 and FeOOH, but low for compounds with a narrow distribution such as Fe3O4. The results of wet-dry cycling tests on weathering steel with NaCl particles on the surface showed that the transition of corrosion products during the corrosion progress can be analyzed from optical microscope images.

Bookmark

Share it with SNS

Article Title

Composition Analysis of Corrosion Products on Steel by Machine Learning of Optical Microscopic Images

Determination of Distribution and Structures of Manganese Aqua and Chloro Complexes in Hydrochloric Acid Solutions at 298 K

Masahito Uchikoshi, Kenʼichi Kimijima, Kozo Shinoda

Abstract

As part of the research on metal aqua and chloro complexes in hydrochloric acid solutions, which is one of the fundamentals in the development of marine resource and the hydrometallurgical process, we have investigated distributions and structures of metal aqua and chloro complexes have been analyzed. The adsorption behavior of manganese species on anion exchange resin was investigated to understand the approximate distribution of manganese aqua and chloro complexes and found that anionic manganese complexes are formed in the concentrated hydrochloric acid solutions. The UV-vis absorption spectra of the manganese species in hydrochloric acid solutions at 298 K were collected for analysis of complex formation behavior. It was determined that the number of complex species to be three using the first derivative test. A series of UV-vis absorption spectra was analyzed using the thermodynamic model fitting analysis. As the results, the distribution of manganese aqua and chloro complexes and their stability constants were determined. The XANES and EXAFS spectra of individual species were obtained dividing a series of the spectra by the distribution of complexes in matrix form. The individual EXAFS spectra were examined using FEFF fitting analysis. The three manganese aqua and chloro complexes are [MnII(H2O)x]2+ (x = 4, 5, or 6), [MnIICl2(H2O)4]0,and [MnIICl4]2−. Only [MnIICl2(H2O)4]0 was confirmed to have an octahedral structure. The structures of the rest of complexes were not clearly determined.

Bookmark

Share it with SNS

Article Title

Determination of Distribution and Structures of Manganese Aqua and Chloro Complexes in Hydrochloric Acid Solutions at 298 K

Effect of Accumulation of Molten Slag and Iron at Blast Furnace Hearth on Gas Pressure Drop

Ryotaro Matsunaga, Yusuke Kashihara, Kazuhira Ichikawa, Toshiyuki Hirosawa, Tetsuya Yamamoto

Abstract

In the lower part of the blast furnace, molten slag and iron accumulate in the coke packed bed and is drained from the tapping hole. However, if tapping rate is reduced, these melts accumulate and an increase in the gas pressure drop occurs. This leads to the furnace troubles such as raw materials hanging.

Bookmark

Share it with SNS

Article Title

Effect of Accumulation of Molten Slag and Iron at Blast Furnace Hearth on Gas Pressure Drop

Automatic Detection Method of Camera Direction from Target Normal Direction in Sampling Moire Method and its Application to Displacements Measurement of Large Structures

Wei Jiang, Aoi Tamura, Idaku Ishii, Kohei Shimasaki, Tomohiko Ito, Yoshiyuki Umegaki, Motoharu Fujigaki

Abstract

Large structures, such as bridges or unloader cranes in a steel plant, require health inspection methods to monitor their operation. Optical inspection methods offer numerous advantages for these large structures compared to traditional contact-based inspection methods. The sampling moire method is one such phase analysis method. Its features include high precision and non-contact field inspection. When measuring large structures, the measuring instruments are often positioned far away, sometimes several hundred meters, from the target. Calibration of such larger structures while in motion is nearly impossible. In this paper, the authors propose a calibration-free sampling moire method for measuring 3-axis displacements. This method initially measures the angles between cameras and the target. Subsequently, these angles are used to calculate a coefficient array, which translates phase differences into displacement values. Thus, the proposed method enables measurement of larger structures situated at a distance. Indoor experiments were conducted to verify the principles of the proposed method, and outdoor experiments were performed in a real steel plant to measure the displacements of an actual unloader crane. The results demonstrate that the proposed method can accurately measure the displacements of a working unloader crane.

Readers Who Read This Article Also Read

Bookmark

Share it with SNS

Article Title

Automatic Detection Method of Camera Direction from Target Normal Direction in Sampling Moire Method and its Application to Displacements Measurement of Large Structures

Relation between Surface Appearance and Corrosion Depth Distribution of Carbon Steel under Atmospheric Corrosion Environment

Yu Sugawara, Takahiro Igarashi

Abstract

Degradation due to atmospheric corrosion is an important problem for steel structures such as bridges. In order to maintain steel structures safely over a long period of time, there is a need for a low-cost and easy-to-use method to evaluate corrosion degradation. In this study, corrosion morphology under atmospheric corrosion environment was focused on. The relation between the surface appearance and the distribution of corrosion depth of the carbon steel specimen after atmospheric exposure was analyzed, and the prediction of corrosion morphology under rust layers by surface observation of steel specimens was examined. It was found that deeply-corroded areas were possible to be located within the dark brown regions in the rusted specimen after the atmospheric exposure. As the exposure period increased, the correspondence between the dark brown regions in the rusted specimen and deeply-corroded areas became clearer. Since the corrosion progressed more locally as the exposure period increased, it is considered that the surface appearance of the rusted specimen showed traces of the deeply-corroded areas.

Bookmark

Share it with SNS

Article Title

Relation between Surface Appearance and Corrosion Depth Distribution of Carbon Steel under Atmospheric Corrosion Environment

Effect of Wettability on the Behavior of Non-metallic Inclusions in the Submerged Entry Nozzle in CC Mold

Tomoharu Nakane, Hiroshi Harada

Abstract

Molten steel flow in the submerged entry nozzle (SEN) largely affects the cast steel quality. However, it wasn’t clarified how non-metallic inclusions behave at the front of nozzle wall in the SEN. One of the reasons is that the contact angle of inclusions with molten steel is bigger than 90 degree and the effect of wettability of the inclusions and nozzle wall on the multi-phase flow behavior in SEN has not been fully clarified. In this study, water model to simulate the multi-phase flow in the SEN has been constructed to investigate the effect of wettability of particles and the nozzle wall on the fluid flow by changing the contact angle of the surface of particles and the nozzle wall. Additionally, an endoscope has been installed into the stopper in order to directly observe the behavior of particles in the SEN. As a result, it was found that particles coated with hydrophobic agent are swept away as if they hit on the nozzle wall and changed the flow direction in the air. This is why the air film was surrounded around the particle by the hydrophobic treatment and cavity bridge was formed between the hydrophobic treated particles in the water. The adhesion force acting between the hydrophobic treated particles was calculated by theoretical analysis and the aforementioned adhesion force could not be ignored compared to the buoyancy force and the drag force in the water.

Readers Who Read This Article Also Read

Bookmark

Share it with SNS

Article Title

Effect of Wettability on the Behavior of Non-metallic Inclusions in the Submerged Entry Nozzle in CC Mold

Domain Wall Structure Model of through the Thickness of Fe-Si Sheet Studied by X ray Topography

Takashi Kataoka, Yusuke Kawamura, Toshiro Futagi, Yoshiyuki Ushigami

Abstract

Fe-Si sheet, which has {110}<001> crystal orientation (Goss-FeSi), consists of Basic domain and Lancet-comb domain. Although the geometric structures of the Lancet-comb domain have been predicted by theoretical aspects, they have not been proved by experimental studies.

Bookmark

Share it with SNS

Article Title

Domain Wall Structure Model of through the Thickness of Fe-Si Sheet Studied by X ray Topography

Effect of Combined Additional B and Mo on Recrystallization Behavior in Low Carbon Steel

Yasuyuki Ogisu, Takeshi Toyoda, Masaaki Fujioka, Jun Takahashi

Abstract

Effect of combined addition of boron (B) and molybdenum (Mo) on recrystallization behavior in austenite was investigated using low-carbon steels. The B-Mo combined added steel remarkably retarded recrystallization after hot deformation, compared to the steels added individually. Three-dimensional atom probe analysis revealed that the addition of B significantly increases the amount of Mo segregation in the austenite grain boundaries. Thermodynamic calculations based on the grain boundary phase model suggested that the interaction between B and Mo atoms increases the grain boundary segregation energy of Mo. The solute drag force was estimated by Cahn's model using the increased segregation energy of Mo, which quantitatively explained the remarkable retardation in recrystallization in the B-Mo combined steel.

Readers Who Read This Article Also Read

Bookmark

Share it with SNS

Article Title

Effect of Combined Additional B and Mo on Recrystallization Behavior in Low Carbon Steel

Influence of Tensile Stress during Annealing on Primary Recrystallization Texture Development in Fe-3%Si Alloy

Nobusato Morishige, Yoshiyuki Ushigami, Kohsaku Ushioda

Abstract

Primary recrystallization texture strongly influences the magnetic properties of grain-oriented electrical steel through secondary recrystallization. In this study, the effect of applied tensile stress during annealing on grain growth and primary recrystallization texture formation in Fe-3%Si alloy was investigated. It was revealed that grain growth is promoted under the condition of applied tension, and the intensity of {411}<148> orientation increases, while the intensity of {111}<112> orientation decreases. The changes in grain diameters and textures are explained by the normal grain growth with the size advantage of larger {411}<148> grains and disadvantage of smaller {111}<112> grains than the average sized grains. Moreover, KAM value of {111}<112> grains was confirmed to be larger than that of {411}<148> grains after tension annealing. This suggests that the stored energy in {111}<112> grains is larger than that in {411}<148> grains, which would promote the selective growth of {411}<148> grains with SIBM mechanism by consuming {111}<112> grains with relatively higher stored energy.

Bookmark

Share it with SNS

Article Title

Influence of Tensile Stress during Annealing on Primary Recrystallization Texture Development in Fe-3%Si Alloy

Influence of Nitrogen Content and Deformation Temperatures on Dislocation Structures in Austenitic Stainless Steels

Soh Yabuki, Yasuhito Kawahara, Shunya Kobatake, Chikako Takushima, Jun-ichi Hamada, Kenji Kaneko

Abstract

Nitrogen-added austenitic stainless steels exhibit excellent work-hardenability due to planar slips of dislocations. Two mechanisms of the planar slip have been proposed so far: glide plane softening mechanism and stacking-fault energy (SFE) reduction mechanism, which are thought to be dependent on nitrogen content and deformation temperature. In this study, conventional TEM, STEM-EDS and HR-STEM characterizations were carried out to clarify the influences of deformation temperature and nitrogen content on the dislocation characteristics of austenitic stainless steels. In the case of the nitrogen-added steel, the dislocation configurations became planar at a high temperature, 973 K. HR-STEM analysis revealed that SFE decreased with N addition and increased with temperature increase. Weak-beam TEM and HR-STEM analyses revealed that the planar dislocations were composed of 60 mixed-dislocations and SFs at room temperature, and edge-dislocation and SFs at 973 K. These results suggested that the edge components of defects interacted elastically with N and N-Cr pairs and contributed to the origin of the planar slips.

Bookmark

Share it with SNS

Article Title

Influence of Nitrogen Content and Deformation Temperatures on Dislocation Structures in Austenitic Stainless Steels

Warm V-Bendabilites and Hydrogen Embrittlement Properties of Ultrahigh-Strength Quenching and Partitioning-TRIP Steel Sheets

Tomohiko Hojo, Akihiko Nagasaka, Chihaya Tabata, Yuki Shibayama, Junya Kobayashi, Eiji Akiyama

Abstract

The warm V-bendabilities and hydrogen embrittlement properties of ultrahigh-strength Quenching and Partitioning (QP)-Transformation-Induced Plasticity (TRIP) steel sheets were investigated to apply the QP-TRIP steel sheets for automotive structural parts manufactured by cold or warm press forming. V-bending tests were carried out at a crosshead speed of 1 mm/min at V-bending temperatures of 25, 100 and 150 ℃ using a hydraulic servo testing machine with a 88-degree V-punch (punch tip radius R=2 mm, R/t0=1.7) and a V-dice (dice groove size l=12 mm, dice shoulder diameter 0.8 mm) using V-bend specimens with dimensions of 5 mm width, 50 mm length and 1.2 mm thickness without and with hydrogen. Hydrogen charging was conducted by means of cathodic charging using a 3 wt% NaCl+3 g/L NH4SCN solution at a current density of 10 A/m2 for 48 h before V-bending. The main results were obtained as follows.

Bookmark

Share it with SNS

Article Title

Warm V-Bendabilites and Hydrogen Embrittlement Properties of Ultrahigh-Strength Quenching and Partitioning-TRIP Steel Sheets

Construction of a Gigahertz Measurement System and Application of Non-destructive Testing Inside Reinforced Concrete

Tadao Tanabe

Abstract

A spectral measurement system using a sub-THz source in the bandwidth up to 100 GHz, obtained by multiplying and amplifying a frequency-variable signal in the GHz band operated by a silicon semiconductor device, was constructed in conjunction with a frequency-tunable single-frequency THz source using GaP, which has been developed previously, in a transmission and reflection optical arrangement. The absorption spectra of ferrous corrosion products and the reflective imaging of metal fragments hidden behind concrete plate were measured. These results of the sub-THz and THz waves suggest that the interior of building structures can be inspected non-destructively based on the dielectric constant-based absorption and reflection of corrosion products and metals inside the concrete and metal surface under coating respectively, which have a high transmission property.

Bookmark

Share it with SNS

Article Title

Construction of a Gigahertz Measurement System and Application of Non-destructive Testing Inside Reinforced Concrete

Mechanical Properties and Microstructure of High Strength Steel for Fracture Suppression and High Absorbed Energy in Automobile Collision

Shinsuke Komine, Tatsuya Nakagaito, Shinjiro Kaneko, Yuki Toji, Tomohiro Sakaidani, Kentaro Sato

Abstract

A fundamental study on the axial crush performances of HSS (High Strength Steel) was carried out to clarify the effects of microstructure and mechanical properties on crashworthiness. Axial crush tests were performed to evaluate the crush performances of the HSS with different microstructures and mechanical properties and identify the fracture origins. The cracks in the press formed area were observed and the cracks led to the fractures. The high λ (Hole expansion ratio) steel showed excellent crush performances by crack suppression. Crash deformation in the press formed area was simulated by the ORB (Orthogonally Reverse Bending) fracture tests and the crack suppression factors were investigated. Through the ORB fracture test, it was clarified that the reduction of the hardness gaps between phases and the refinement of the hard phases (Fresh martensite) were effective for suppressing cracks in the press formed area. These microstructures were occurred by the Q&P (Quenching & Partitioning) process for increasing λ. Therefore, it was found that the microstructural design for increasing λ also contributed to excellent crush performances.

Bookmark

Share it with SNS

Article Title

Mechanical Properties and Microstructure of High Strength Steel for Fracture Suppression and High Absorbed Energy in Automobile Collision

Year-round Monitoring of Temperature and Humidity using a Sensor Network installed in the Hokkaido Centennial Memorial Tower

Kazuhisa Azumi, Masatoshi Sakairi, Koji Fushimi, Takashi Sato, Ken Mikami, Masazumi Miura

Abstract

Daily and seasonal changes in temperature (T) and relative humidity (RH) were monitored using a sensor network system installed in the Hokkaido Centennial Memorial Tower, built more than 50 years ago using weathering steel, to investigate its corrosion condition. Five T-RH sensors were set at the south side wall, inside the south tower, in the semi-open central area, inside the north tower, and on the north side wall on the 4th, 14th, and 24th floors. The T changed as a function of altitude, location in the floor, season, weather, solar radiation, diurnal cycle, distance from the wall, etc. The highest T of the south wall at daytime in the winter season could rise more than 30 °C even if the outer temperature was below 0 °C due to solar radiation causing the repetition of ice or snow melting in the daytime and freezing of water at night. The change in RH and T inside the tower followed a Tomashov-type RH-T curve (high RH at low T in the morning and evening). In winter, however, T and RH distribution, i.e., high-RH (> ca.60%) area below the freezing point and low-RH area with the high-T, caused air transportation inside the tower, condensation (and freezing) in the low-T area, and drying in the high-T area. In the visual inspections, severe corrosion, such as blistering and peeling, has been observed at the bottom of the tower, where snow has accumulated, and rainwater has stayed for a long time, especially at welds and joints.

Bookmark

Share it with SNS

Article Title

Year-round Monitoring of Temperature and Humidity using a Sensor Network installed in the Hokkaido Centennial Memorial Tower

Residual Stresses in Polycrystalline Iron Alloys Measured by X-ray Diffraction and Related Microstructure

Shigeru Suzuki, Shigeo Sato, Susumu Imashuku, Hiroyuki Sato, Shun-ichiro Tanaka

Abstract

This article describes results of the residual stress measurements in different iron alloys using a few non-destructive techniques based on X-ray diffraction. It was shown that the results provide useful information for understanding the microstructural phenomenon in each alloy, although these techniques are not universally applicable to various cases. In this paper, the residual stresses formed during stress-induced martensitic transformation and its reverse transformation in shape memory alloys, the residual stresses balancing between two phases in duplex stainless steels and the residual stresses formed by inhomogeneous plastic strains in polycrystalline twin-induced plasticity steels are shown. It is important to select an adequate method according to the phenomena and properties of interest in iron alloys. The residual stresses formed in a high-entropy alloy containing iron are also presented, taking into account into the inhomogeneity in bulk. The residual stresses and related microstructural data in materials in structures and device components are considered to be effective parameters for evaluating their mechanical properties. While modern diffraction measurement methods are relatively easy to be operated, it is noted that the results include issues related to the microstructure of the materials. These issues should also be discussed in the residual stress measurements at different scales, and reliable fundamental data related to residual stress considering the microstructure would be necessary for discussion.

Bookmark

Share it with SNS

Article Title

Residual Stresses in Polycrystalline Iron Alloys Measured by X-ray Diffraction and Related Microstructure

Characterization of Anisotropic Properties of Functional Iron Alloy Sheets

Masahito Watanabe, Kiyoshi Urakawa, Yoshio Ishigaki, Taisuke Furuse, Motohiro Kasuya, Shigeo Sato, Shigeru Suzuki

Abstract

To understand the anisotropy of properties in FeCo-V alloy sheets, the Young's modulus, texture, and residual stress of samples of different treatments were investigated using the X-ray diffraction method. In the cold-rolled alloy sheets, the anisotropy of Young's modulus in different directions within the sheet plane was similar to that of the annealed samples at 600 °C, although there was some variation. The anisotropy of the Young's modulus was different from that of the cold-rolled and annealed samples at low temperatures. According to the results of texture measurements on alloy sheets subjected to each treatment, the direction of the lower Young's modulus almost corresponds to a specific texture component, suggesting that the texture component affects the anisotropy of the Young's modulus. X-ray diffraction rings from alloy sheets are used in the residual stress measurement, which may contain information on the process of alloy sheets and changes in the texture due to heat treatment. Residual stress shows anisotropy within the surface of cold-rolled alloy sheets, indicating high compressive residual stress in the rolling direction and in the transverse direction. In general, lower residual stress in the sheets annealed at 600 °C may be related to dislocation rearrangement in the alloys. Furthermore, in the samples annealed at 850 °C, recrystallization and related phenomena are reflected in the deviation from the plot for residual stress, which may also affect the texture.

Bookmark

Share it with SNS

Article Title

Characterization of Anisotropic Properties of Functional Iron Alloy Sheets

Formation Mechanism of Secondary Inclusions in Fe-36mass%Ni Alloy Using a Novel Combination Analysis Technique

Hiroshi Fukaya, Jonah Gamutan, Makoto Kubo, Shintaro Yano, Shigeru Suzuki, Takahiro Miki

Abstract

Controlling the size, number, and composition of secondary inclusions is vital in the production of high-quality steels. In this study, experimental and computational investigation of the relationship between secondary inclusion formation in Fe-36mass%Ni alloy and cooling rate was carried out. Assuming the case of large ingots, solidification experiments using various cooling rates (0.17 to 128 K/min) were employed and the size, number, composition, and distribution of inclusions were analyzed by SEM-EDS automatic inclusion analysis. Like previous studies, inclusion number density increased with increasing cooling rate, while inclusion size decreased with increase of cooling rate. On the contrary, oxide inclusion area fraction was found to have little relationship with the cooling rate and was instead found related with oxygen content of the sample. As a new attempt to investigate the relationship between microsegregation and secondary inclusion formation, a combination of SEM-EDS analysis and EPMA mapping analysis was carried out. By superimposing information of microsegregation and inclusions, it was found that high-Al2O3 inclusions formed during the early stage of solidification, whereas low-Al2O3 inclusions formed during the later stage of solidification. These findings suggest that Al2O3 inclusions formed in the early stage of solidification reacted with the remaining Si-enriched liquid steel and changed into low-Al2O3 inclusions. Experimental results were also confirmed by thermodynamic calculations. Present work made it possible to understand deeper the relationship between microsegregation and secondary inclusion formation.

Bookmark

Share it with SNS

Article Title

Formation Mechanism of Secondary Inclusions in Fe-36mass%Ni Alloy Using a Novel Combination Analysis Technique

Displacement Distribution Monitoring of an Unloader Crane in Ironworks Using High-speed and High-resolution Vision

Feiyue Wang, Kohei Shimasaki, Shaopeng Hu, Idaku Ishii, Yoshiyuki Umegaki, Tomohiko Ito

Abstract

In this study, we develop a high-speed, high-resolution vision system that enables real-time measurement of deflection displacement distribution in cranes with long beam structures. It can measure dynamic displacement distribution with sub-pixel accuracy in real time by executing digital image correlation for 4096×904 images at 100fps. Millimeter-level deflections at tens of points on a crane are measurable with the position of its moving load when a camera is tens of meters away from the crane. The trolly of a crane indicates the load position, and our system can also analyze deflection influence lines at all points on the crane as speed-invariant features that indicate its structural property. The effectiveness of our vision-based displacement measurement is demonstrated by showing experimental results for (1) a 1-m-length belt conveyor, and (2) an unloader crane with a 98-m beam structure operating in ironworks.

Bookmark

Share it with SNS

Article Title

Displacement Distribution Monitoring of an Unloader Crane in Ironworks Using High-speed and High-resolution Vision

Estimation Method of Whiteline Intensity of Platinum Compounds at L3 Edge XANES and the Oxidation Number Using a Laboratory-type Spectrometer

Takashi Yamamoto, Kazunori Miyamoto

Abstract

Pt L3 edge XANES spectra of various kinds of platinum compounds were recorded using a laboratory-type X-ray absorption spectrometer. In order to investigate precision and the accuracy for oxidation state analysis of platinum species with a simple method, the white line intensity was evaluated by least squares fitting using four kinds of profile functions (Gaussian, Lorentzian and two types of pseudo-Voigt functions) and one arctangent function for continuum state. Differences in estimated values and the deviations depending on the type of profile function adopted were discussed. White line intensity could be determined easily and reproducibly using pseudo-Voigt function where a fraction of Lorentzian function is variable. The relationship between oxidation number of Pt compounds and white line area obtained by pseudo-Voigt method are the most preferable. The height of the white line for divalent compounds varies greatly in some cases, and then it is inappropriate to apply the height to estimation of the oxidation number of unknown samples. The changes in platinum species of silica supported Pt(NH3)4Cl2 of a catalyst precursor during air calcination was examined by in-situ XANES. The platinum species exist as divalent species up to 473 K, and changed to zero-valent between 473 and 573 K. The present in-situ laboratory XAFS experiment and the oxidation state analysis is consistent with SR XAFS studies by other research group.

Readers Who Read This Article Also Read

Bookmark

Share it with SNS

Article Title

Estimation Method of Whiteline Intensity of Platinum Compounds at L3 Edge XANES and the Oxidation Number Using a Laboratory-type Spectrometer

Polarization X-Ray Fluorescence Analysis by Milliwatt X-ray Tube

Jun Kawai, Toshihide Kato, Susumu Imashuku

Abstract

X-ray spectra scattered to 90°were measured for various scatterers of 5-mm thick B4C, acrylic, titanium, iron, zirconium, and lead plates, and their combinations such as B4C(5 mm thick) on acrylic plate (1 or 5 mm thick). The degree of polarization was estimated from the observed X-ray spectra at 0°and 90°. Using the best scatterer as an X-ray polarizer for each samples, polarization X-ray fluorescence (XRF) spectra of various samples such as cabtyre cable, book cover made of synthetic-resin, and steel making slag, compared with non-polarization XRF spectra. Toxic elements in some samples were more sensitive for polarized XRF, while other samples were more sensitive for non-polarized XRF. The reasons for such contradicted experimental results were discussed. Most of the measurements were performed by 15 mW X-ray tube power for polarization XRF, and by 3 mW for non-polarized XRF. The meanings of lowest power XRF measurements in the literature were also discussed. This kind of low power experiments may open the possibility of easy way of experiments, and non-invasive XRF analysis for cultural heritage.

Bookmark

Share it with SNS

Article Title

Polarization X-Ray Fluorescence Analysis by Milliwatt X-ray Tube

In-situ Observation of the Environmental Resistance of Pure Iron Using Hydrogen and Oxygen Sensors in the Environment Simulating Hydrogen Combustion

Michihisa Fukumoto, Hiroki Takahashi

Abstract

The environmental resistance of pure iron was evaluated with oxygen and hydrogen sensor installed after the oxidation furnace. The amount of introduced oxygen was precisely controlled by oxygen pump-sensor at the front stage of the oxidation furnace and the reaction with hydrogen was analyzed. As a result, when oxygen was supplied, a reaction between hydrogen and oxygen occurred, but when sufficient oxygen was not supplied, a hydrogen-vapor environment was created and oxidation was not accelerated. However, when the amount of supplied oxygen was excessive, the environment became oxygen-steam environment and the oxidation was accelerated. At that time, it was clarified that the oxidation by oxygen was dominant under the oxygen-water vapor environment, and the mass gain increased. In addition, the border of the region dominated by oxygen oxidation and that by steam oxidation was clarified by precisely controlling the amount of supplied oxygen by the oxygen pump sensor.

Bookmark

Share it with SNS

Article Title

In-situ Observation of the Environmental Resistance of Pure Iron Using Hydrogen and Oxygen Sensors in the Environment Simulating Hydrogen Combustion

Gas Pressure Measurement Beneath of Oxide Scale during High-temperature Oxidation of Steel

Ryoto Okumura, Yuto Adachi, Yasumitsu Kondo

Abstract

Blistering occurs when oxide scale swells during oxidation at steel high temperatures.Blistered scale causes surface defects when steels are rolled. An assumption has been proposed that the pressure of CO and CO2 gas generation beneath the scale causes blisters. This study the qualitative measurements of the gas pressure beneath the oxide scale were tried.A stainless tube was set in order to connect to the beneath the scale during oxidation.Positive pressures were confirmed beneath oxide scale. Also gas permeability through FeO mono-layer scale was obtained.

Bookmark

Share it with SNS

Article Title

Gas Pressure Measurement Beneath of Oxide Scale during High-temperature Oxidation of Steel

A Method for the Analysis of Chromium at Sub-μg L−1 Level Using a Portable Total Reflection X-ray Fluorescence Spectrometer

Rihoko Miyazaki, Kosei Oikawa, Shinsuke Kunimura

Abstract

In this study, total reflection X-ray fluorescence (TXRF) spectra of dry residues of 10 μL, 100 µL, 200 µL, and 400 μL droplets of a solution containing 10 μg L−1 of Cr on hydrophobic film coated sample holders were measured by a portable TXRF spectrometer, and these spectra were compared. The net intensity of the Cr Kα peak per the concentration of Cr in the sample solution (counts / μg L−1) increased with an increase in the volume of a droplet of the sample solution. This was because the mass of Cr in the dry residue increased with an increase in the volume of a droplet of the sample solution. This enhancement in the net intensity of the Cr Kα peak per the concentration of Cr led to a significant improvement in the detection limit expressed as the concentration of Cr. Detection limits for Cr obtained from the measurements of the dry residues of 10 μL, 100 µL, 200 µL, and 400 μL droplets of the sample solution were 2.1 μg L−1, 0.30 μg L−1, 0.13 μg L−1, and 0.09 μg L−1, respectively. Measuring the dry residue of a large volume droplet of a water sample would be useful for the analysis of trace elements in the sample.

Bookmark

Share it with SNS

Article Title

A Method for the Analysis of Chromium at Sub-μg L−1 Level Using a Portable Total Reflection X-ray Fluorescence Spectrometer

Rapid Identification of Crystal Structure of Alumina Scale on Heat-resistant Alloy

Susumu Imashuku

Abstract

Identifying a crystal structure of alumina (Al2O3) scale is critical for evaluating the performance of heat-resistant alloys because α-Al2O3 is stable and protective against high-temperature oxidation and corrosion but θ- and g-Al2O3 provide poor oxidation resistance. Conventional methods to identify crystal structures of Al2O3 scales are time-consuming. Herein, the author proposes a method to rapidly identify crystal structures of Al2O3 scales on β-NiAl by obtaining their cathodoluminescence (CL) spectra. α-, θ-, and g-Al2O3 can be identified by detecting a sharp peak at 695.8 nm and 686.3 nm, and a broad peak at around 700 nm, respectively, in CL spectra. Concentrations of α-, θ-, and g-Al2O3 scales can be determined roughly from intensities of these peaks. This method can be applied to areas ranging from the millimeter to micrometer scale, and the acquisition time for the CL spectra was less than 10 s. The results indicate that obtaining CL spectra contributes to the identification of crystal structures of Al2O3 scales on heat-resistant alloys and a reduction in time to evaluate the performance of heat-resistant alloys.

Bookmark

Share it with SNS

Article Title

Rapid Identification of Crystal Structure of Alumina Scale on Heat-resistant Alloy

Article Access Ranking

19 Jul. (Last 30 Days)

You can use this feature after you logged into the site.
Please click the button below.

Advanced Search

Article Title

Author

Abstract

Journal Title

Year

Please enter the publication date
with Christian era
(4 digits).

Please enter your search criteria.