著者

作井 誠太 中村 正久 布村 成具

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.48, no.1, pp.28-34, 1962-01-01 (Released:2010-02-22)

参考文献数

7

被引用文献数

4 1

---

This paper describes of the influences of deformation rate of wide range on the tensile impact properties of several steels by using a high-speed impact-tensile testing machine with a large rotary disk. The deformation rate was varied from static region to 80m/s, and the testing temperature from room temperature to 800°C. The results obtained were summarized as follows:(1) Blue brittleness was observed clearly in mild steel and two alloy steels, and temperature range of blue brittleness shifted to higher temperature with increasing rate of deformation. This shift was conspiquous up to a speed of deformation of 10m/s, but was decreased beyond this speed. Moreover, at the speed of 40m/s the blue brittleness temperature was decreased on the contrary.(2) The similar dependence on deformation rate was also made clear, with regard to the brittleness of 18-8 stainless steel which was due to the effect similar to that causing blue brittleness as well as the brittleness of pure copper at elevated temperature.(3) At higher temperature over 600°C, the critical impact velocity was not observed so distinctly as obtained at room temperature. Tensile strength was lowered with a larger scattering as the deformation rate was increased, while, correspondingly, the value of elongation or reduction of area showed tendency to be rather larger. This phenomenon, named by the authors as “high-rate deformation softening”, was discussed in relation to the loadtime curves observed experimentally.

著者

山本 俊二

出版者

社団法人日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.55, no.4, pp.326-337, 1969

被引用文献数

6

著者

山尾 文孝 佐々 健介 岩井 一彦 浅井 滋生

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.83, no.1, pp.30-35, 1997-01-01 (Released:2009-06-19)

参考文献数

11

被引用文献数

33 41

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The principle on separating inclusions in a molten metal by using a fixed alternating magnetic field has been confirmed through experiments with molten aluminium. The separating efficiency of inclusions is studied through experimental and analytical ways under different operating conditions. The mathematical model to predict the separating efficiency is developed and the efficiencies predicted by the model are compared with the experimental ones.A feasibility study on the application of an electromagnetic inclusion separation in a molten steel is performed. An operating non-dimensional parameter, Y ≡(ρfdp2Be2LtS) (μfμeWdt2) which characterizes an electromagnetic inclusion separation process is newly proposed.

著者

川本 正幸 柳楽 知也

出版者

一般社団法人 日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.100, no.4, pp.472-484, 2014

被引用文献数

10

---

The continuous casting technology of steels in Japan has been well-developed over the past 60 years since the introduction of a continuous casting machine and its technology from Europe. The continuous casting ratio of steels has reached over 98%. A large number of researchers have been conducted on fundamental researches for the improvement of continuous casting technologies. Some of the development histories are summarized in the book, entitled ìHistory of Steel Continuous Casting Technology in Japanî in 1996. In recent years, a near-net-casting has been also developed for higher efficiencies and productivity in many countries. This paper reviews the histories of development in the continuous casting in Japan on technologies regarding (1) Pouring to mold, (2) mold lubrication, (3) cooling of a solidifying shell, (4) machine type, (5) reduction of casting defects, (6) tundish, (7) measurement and control processes and (8) different types continuous castings. The fundamental researches on the major casting defects including macrosegregation, cracking and inclusions that are formed in a continuous casting are also reviewed. Some brief comments on the further development of continuous casting in the future are described.

著者

佐藤 忠雄

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.43, no.7, pp.745-748, 1957-07-01 (Released:2009-05-26)

参考文献数

5

被引用文献数

1

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Recently the heat resisting alloys have made remarkable developments. There are few differences in the essential consideration of chemical constituents, but the aging time has been so prolonged that the stability of structure and strength at elevated temperature much increased. In heat-resisting alloys, some phenomena such as creep and fatigue take place under repeated stresses during practical use.The transformation and precipitation of the alloys are accelerated by these repeated stresses so that there occurs a change of the volume and a decrease in the creep or the fatigue strength.Further, a systematic research on these problems is needed. It is also presumed neccessary that new manufacturing techniques, for example, vacuum-melting, vacuum-casting and hotextrusion should be introduced for further improvements in heat resisting alloys.

著者

武田 喜三

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.64, no.14, pp.2239-2246, 1978-12-01 (Released:2010-02-22)

被引用文献数

1

著者

小野寺 龍太 森川 龍哉 上木原 竜太

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.87, no.1, pp.63-69, 2001-01-01 (Released:2009-06-19)

参考文献数

7

被引用文献数

1 1

---

The yield point phenomena in low carbon steel have been explained by the Cottrell or the Johnston-Gilman theory in terms of microscopic variables such as dislocation density, dislocation velocity and the interaction energy between dislocation and solute atom. However, the lower yield stress and the amount of the Lüders strain (stretcher strain) seems not to have been predicted by the above theories. In the present work we tried to explain the phenomena quantitatively by a phenomenological (rheological) model using macroscopic variables such as work-hardening rate and the strain rate sensitivity of flow stress which we can be measured by tensile test. In the model a new internal stress was introduced which is supposed to be work (strain)-softened and age-hardened. Numerical calculation showed that the model can predict the values of the upper and lower yield stress and the amount of the Lüders strain, and the effect of strain rate on these characteristics.

著者

原勢 二郎 太田 国照 清水 亮 竹下 哲郎

出版者

社団法人日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.76, no.9, pp.1520-1527, 1990

被引用文献数

2 7

---

Orientation distribution in the 17%Cr stainless steel rough rolled with inter-pass time of 10s (specimen A) and 30s (specimen B) respectively were investigated utilizing SEM-ECP (selected area electron channeling pattern).<BR>Large colonies, groups of grains with the same orientation, of {100} <011>orientation are found in the specimen A after rough rolling. It is proposed to be formed by the poor static recrystallization during rough rolling due to the short inter-pass time and the suppression effect of static recrystallization caused by the &alpha;-&gamma; transformations immediately after the final pass of the rough rolling.<BR>Large ridging is observed in the cold rolled and annealed specimen A.<BR>The cause of the large ridging is considered to be due to the large colonies of {100} <011> orientation inherited from the rough rolled stage and scattered asymmetrically along the central line of the specimen thickness.

著者

藤井 哲雄

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.62, no.10, pp.1398-1411, 1976-09-01 (Released:2010-02-22)

参考文献数

14

被引用文献数

1 1

著者

的場 理一郎 中田 伸生 二村 裕一 土山 聡宏 高木 節雄

出版者

一般社団法人 日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.93, no.7, pp.513-517, 2007-07-01 (Released:2009-02-13)

参考文献数

9

被引用文献数

17 16

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The “nominal grain size” (average grain size) is generally applied to Hall-Petch relationship to evaluate grain refinement strengthening in polycrystalline materials. However, the steels with wide grain size distribution (duplex-grained structure) may not deform uniformly but yield preferentially from larger grains to finer ones. This phenomenon is called “micro-yielding”. In this study, the effect of duplex-grained structure on the yield stress was investigated by using some IF steels with different grain size distribution. As a result of tensile testing, the yield stress of duplex-grained steels could be conventionally plotted on the Hall-Petch relationship as a function of (nominal grain size)-1/2 in the range from 100 to 10 μm, even though the micro-yielding phenomenon occurred within the coarse grains at a lower stress than the macroscopic yield stress. When the volume fraction of grains with identical size is summed from larger-sized ones, the summated volume fraction (defined as the integrated volume fraction) always reaches 70-80 vol% at the nominal grain size irrespective of the difference in grain size distribution. These results suggest that polycrystalline materials including duplex-grained structure materials cause the macroscopic yielding when the grains of 70-80 vol% are micro-yielded.

著者

森本 忠興

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.57, no.1, pp.116-124, 1971-01-01 (Released:2012-02-20)

参考文献数

14

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The strength and toughness of a low alloy steel (0.8% carbon), quenched from 850°C and tempered at various temperatures below 600°C, have been investigated by static and dynamic bend tests and static torsion tests. The effect of notch radius on bend properties has also been studied. The results obtained in this study are summarized as follows:(1) The plastic deflection in the static bend test or the impact value decreases exponentially with increasing the stress-concentration factor “α” at the notch root.(2) The appearance of low temperature temper brittleness is markedly affected by test methods, that is, it appears at relatively low tempering temperatures and the embrittlement is more clearly observed in unnotched dynamic bend or static torsion tests than in static notched and unnotched bend tests.(3) An optimum hardness is observed on the fracture strength versus hardness curve in both bend and torsion tests.

著者

河合 正吉

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.47, no.14, pp.1919-1932, 1961-12-01 (Released:2010-10-12)

参考文献数

16

著者

土山 聡宏

出版者

一般社団法人 日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.100, no.9, pp.R20-R21, 2014 (Released:2014-08-31)

参考文献数

2

著者

利岡 靖継 雑賀 喜規 栗山 良員

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.54, no.4, pp.416-426, 1968-03-01 (Released:2010-10-12)

参考文献数

17

被引用文献数

2 2

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A simple method is proposed to predict mechanical properties of heattreated large steel forgings. The method is based on the findings. Firstly, the main considerations for the strength and the ductility are the carbon content of the forging and the microstructures induced during quenching. Secondarily, the microstructures can be computed from available CCT diagrams and cooling rates of quenching in the temperature range of 600°C to 300°C. These findings are verified experimentally on carbon steels and lowalloyed steels containing such elements as Ni, Cr and/or Mo. Equations for the rapid estimates of the cooling rates of steel forgings of the maximum diameter of 1000mm are derived experimentally as follows:log D+0.513 log C=2.37 when quenched in waterlog D+0.699 log C=2.02 oillog D+0.954 log C=1.18 airwhere, D is the diameter of a steel forging in mm. and C the looling rate in the temperature range of 600°C to 300°C in °C/sec.Discussions are given on the validities of the findings and the equations.

著者

梅本 実 田村 今男

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.68, no.3, pp.383-392, 1982-03-01 (Released:2009-06-19)

参考文献数

42

被引用文献数

4 4

著者

郡司 好喜

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.80, no.4, pp.N176-N186, 1994-04-01 (Released:2009-06-19)

参考文献数

36

被引用文献数

3 3

著者

杉本 孝一

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.60, no.14, pp.2203-2220, 1974-12-01 (Released:2010-10-12)

参考文献数

53

被引用文献数

19 17

著者

今宿 晋 大谷 一誓 河合 潤

出版者

一般社団法人 日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.100, no.7, pp.905-910, 2014 (Released:2014-06-30)

参考文献数

23

被引用文献数

1 2

---

We have recently realized an electron probe microanalyzer (EPMA) and cathodoluminescence (CL) spectrometer with a palm-top size chamber including the electron source and the sample stage using a pyroelectric crystal as the electron source. In the present study, we carried out microanalysis and elemental mapping using the portable EPMA and CL spectrometer. As for the portable EPMA, the electron beam bombarded a sample and the wall of the stainless steel chamber due to using a LiTaO3 single crystal with a cuboidal shape. The electron beam was focused on the sample by setting a metal needle on the pyroelectric crystal and covering the needle holder with an insulating material. The spot size of the focused electron beam was 300 μm. We succeeded in elemental analysis in micro-scale region using the focused electron beam. The portable EPMA can also detect light elements such as Mg, Al and Si by introducing the X-ray detector into sample chamber. The portable CL spectrometer can detect ppm order of rare-earth elements in a mineral ore. The portable CL spectrometer can also perform an elemental mapping of rare-earth elements by capturing a CL image with CMOS camera.

著者

福井 彰一

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.55, no.2, pp.151-161, 1969-02-01 (Released:2010-10-12)

参考文献数

13

被引用文献数

16 10

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The influence of tempering on the delayed fracture characteristics in 0.1N HCl solution, the initiationand propagation behavior of cracks in delayed fracture and the hydrogen embrittlement characteristics in-tensile tests have been studied in metallurgical view point for several low-alloy steels with the difference in, carbon content and tempering behavior.In general, the delayed fracture strength ratio (fracture strength at 30hr in life divided by static strength)-varied depending on the hardness of the steel, and showed almost constant value of 0.85 in all steels with thehardness up to Hv 350 and rapidly decreased the value with increase in hardness above Hv 350.Contradictorily to the general aspects described above, an abnormal increase appeared in the delayed.fracture strength ratio for the steel tempered at about 250°C, independently on the hardness of the steel.This phenomenon shifted to the higher tempering temperature as silicon content in the steel was increased.Considering the stabilizing effect of silicon on epsilon carbides, it is supposed that the phenomenon is attributedto the precipitation of epsilon carbides.The cracks in delayed fracture initiated at the prior austenite grain boundaries, but the propagation pathdiffered according as the tempering condition of the steel. It has been observed that the cracks propagatedat the prior austenite grain boundaries in the steels tempered in the temperature range of primary temper-brittleness (500°F embrittlement), and mainly propagated across the interior of the grains the steelstempered in the temperature out of the range of primary temper-brittleness.From the results of the electron microscopic observation of the precipitation behavior of carbides, ithas been observed that cementites precipitated in a line at the prior austenite grain boundaries in the specimenof which crack in delayed fracture propagated along the grain boundaries. The delayed fracturestrength of these steels were inferior to those cracks propagated across the interior of the grains.The dependence of the degree of hydrogen embrittlement, which was indicated as the decrease of the reductionof area in tensile test for the steel dipped in 0.1N HCl solution, on the tempering temperature was in goodagreement with that of the delayed fracture strength in the same solution. This fact suggests that themicrostructure of the steel contributed in the same way to both of the delayed fracture strength and the hydrogen embrittlement.

著者

杉本 克久

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.70, no.7, pp.637-649, 1984-05-01 (Released:2009-06-30)

参考文献数

56

被引用文献数

14 6