Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 47 , Issue 4
Showing 1-15 articles out of 15 articles from the selected issue
  • [in Japanese]
    1961 Volume 47 Issue 4 Pages 573-574
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Ryohei TANAKA, Rokuro ITO
    1961 Volume 47 Issue 4 Pages 575-580
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    The effect of cooling rate in normalizing of copper-bearing low-carbon cast steels containing 0.1% C, 0.5% Si, 1.0% Mn and various amounts of copper up to 3.0%, on the precipitationhardening by subsequent tempering has been studied and discussed. The main results obtained are as follows:
    (1) In steels containing 1.0-1.5% copper, the most significant precipitation-hardening on tempering is found to occur, the hardening being apparent even after a considerably slow cooling by normalizing. While, in steels containing copper more than 2.0%, the precipitation of copper occurs easily during cooling in normalizing, and the hardening due to the subsequent tempering is smaller as compared with that containing less copper.
    (2) It is concluded that during the normalizing-cooling of steels containing copper more than 2.0%, copper-rich phase precipitates quickly at a temperature above 700°C together with ferrite as a binary eutectoid from austenite, facilitating the precipitation of copper from ferrite during cooling down to lower temperatures.
    (3) Due to the cooling rate in normalizing, the copper content, and the tempering, the change of tensile strength of the steels is found to be proportional to the hardness change described above. While, elongation of the steels is decreased only when the cooling rate is increased, and it is not affected by copper content and by tempering treatment at 550°C.
    (4) It is also certified that the addition of copper improves the fluidity of molten steels.
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  • Shoichi NAKANISHI, Akio TAKEMASA
    1961 Volume 47 Issue 4 Pages 581-585
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    Fracture surface of plain carbon steel were observed with an electron microscope.
    The crack initiation and the process of its propagation in a steel which was slowly given tension were examined to some extent in relation to the structure of steel.
    The results were as follows:
    1) The point of crack initiation had a relation with a pearlite banding.
    2) The grain boundaries had a function to absorb the cracks. i. e. ductility of steel was increased in accordance with the grain refining.
    3) The ball-type nonmetallic inclusions (under about 0·5μ) had no effect on crack propagation.
    4) The elongated type nonmetallic inclusions did not arrest the crack propagation.
    5) The nonmetallic inclusions above 5p directly had little effect on initiation and propagation of cracks.
    6)“Tongue” peeled surface was seemed to be an initial stage of twin formation and such deformation absobed the energy at the fracture surface.
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  • Eiichiro ASANO, Toru ISHIDA
    1961 Volume 47 Issue 4 Pages 585-591
    Published: April 01, 1961
    Released: December 22, 2010
    JOURNALS FREE ACCESS
    Effects of addition of some elements on properties of Si-Mn structural steel were investigated. In the report I (Tetsu to Hagané, Vol.45, No.10 (1959) 1158), the effects of addition of V were researched, while in this report II, effects of B and Mo on Si-Mn and Si-Mn-Cr structural steel were studied.
    There were four groups among specimens tested:
    The 1st group, containing 4 grades steel, was prepared for testing the effects of B on properties of Si-Mn steel. The 2nd group, containing 3 grades of steel, was for testing the effects of B with Mo on properties of Si-Mn steel. The 3rd group, containing 3 grades ofsteel, was for testing B, and the 4th group, was for B with Mo on properties of Si-Mn-Cr steel.
    All samples were melted by a high-frequency induction furnace and cast into 10 kg ingots, and then rolled or forged down to 16mm ∅; bars.
    The specimens were tested under various conditions; such as rolled or as forged, furnacecooled or air-cooled after heating and, as quenched-and-tempered.
    Mechanical properties as well as hardenability were tested.
    It was concluded as follows:
    (1) Addition of B to Si-Mn steel was found to enhance both tensile and yield strength as well as hardness, with specimens subjected to quenching and tempering treatment. No appreciable effcet of B, however, was recognized on the strength and hardness of the steel in the case of furnace-cooling or air-cooling treatment. Addition of 0.0050% B to these grades of steel was presumably essential to give the best result on the strength of specimens as quenched and tempered.
    (2) Addition of both B and 0.5% Mo to Si-Mn steel improved the yield and tensile strength as well as hardness of the specimen as quenched and tempered. The similar effects were observed on the hardness of specimens subjected to furnace-cooling or air-cooling. It was found that 0.0050% B was suitable to give the best effect for strengthening of the steels after air cooling or furnace cooling, but that 0.0100% B was essential to give the best effect on it after quenching and tempering.
    (3) Addition of both B and Mo to Si-Mn steel resulted in an increase of pearlitic hardenability, where as addition of only B had no effect on it.
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  • Hideo SHIMODA, Shinsaku ONODERA, Akira TOKUDA, Ryosuke HOMMA, Hiroshi ...
    1961 Volume 47 Issue 4 Pages 591-599
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    In order to investigate into the cause of various deflections liable to take place in turbine shafts during heat-indication test, the authors reproduced deflections experimentally using model shafts as big as about 1/3-1/6 in dimensions of an actual shaft.
    Thus, it was made clear that, besides the physical properties of a shaft itself, surface conditions of a shaft such as the way of sticking of dirts and scales, and conditions of machined surface possibly would be important causes for appearance of the deflections.
    A new type of deflection which, though seemingly resembling the type C deflection, would be due to causes quite different from the said type C was found and designated as type C' deflection. Further it has been made clear that, as well as the deflection of types A and D, this C' type probably would be ascribed to an asymmetric thermal emissivity on the surface of a shaft.
    The results thus obtained from the tests of model shafts were confirmed in practical heatindication tests of turbine shafts
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  • Sadao KOSHIBA, Tsuneo KUNOU
    1961 Volume 47 Issue 4 Pages 599-603
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    Experimental studies were made on the effect of C, Cr, Mo and V on hardness on heat treatments, mechanical properties at elevated temperature, rupture strength, microstructures and deformation ratios of 3% Cr heat-resisting steel, which is used for heat-resisting parts of aeroplane structures.
    Results obtained were as follows:
    (1) With increase of C contents, the hardness on heat treatment and the tensile strength at elevated temperatures were increased. But the rupture strength showed the maximum value at about 0.36% C.
    (2) By further addition of Cr contents, the as quenched-and-tempered hardness below 600°C were increased. The as-tempered hardness, the tensile strength and the rupture strength in a range of high temperature above 650°C were decreased.
    (3) By increase of Mo, the hardness after heat treatment was increased, but the tensile strength at elevated temperature and the rupture strength showed maximum value at about Mo content.
    (4) Addition of V increased the hardness of steel on heat treatment, but the tensile strength at elevated temperatures and the rupture strength became maximum at about0.55%V content.
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  • Masao KAWAHATA
    1961 Volume 47 Issue 4 Pages 604-611
    Published: April 01, 1961
    Released: December 22, 2010
    JOURNALS FREE ACCESS
    As a result of the rapid development of vacuum melting process, many super-alloys have been developed. It is evident that the high temperature properties of these super-alloys depend on various melting processes. It is the purpose of this study to point out the high-temperature properties of A-286 and Incoloy T containing some scavenging elements such as Ti and Al. Therefore, in order to obtain a good comparision between an air-melting and various vacuum-melting techniques, it was first necessary to obtain heats of similar chemical compositions. 10kg electrolytic materials were melted in an alumina or magnesia crucible with a laboratory-scale vacuum-induction equipment which had 25KW capacity and about 60kC frequency.
    Degassing process during vacuum induction melting was done by two methods of carbon and hydrogen refining.
    Attainable oxygen and nitrogen levels in these specimens refined by carbon are lower than those of these specimens refined by hydrogen. 18mm ∅; forged bars made from both air-and vacuum-melted ingots were used for age hardening, short-time tensile test, rotating-bending fatigue test, high-temperature creep-rupture test, electron-microscopy and X-ray examinations.
    In terms of the relationship between rupture time and gas content of each specimen, hightemperature rupture properties of Incoloy T were improved by reducing the gas content.
    On the other hand, the same result was not obtained in the case of A-286. Those were much the same in age-hardened characteristics, short-time tensile strength and rotating-bending fatigue strength by both melting methods but the ductility after tensile test for the vacuum-melted specimens of A-286 were superior to those for the air-melted. According to the results of long-time creep-rupture tests at 650 and 815°C, the rupture strength in the vacuum-melted Incoloy T specimens was especially superior to those of the air-melted.
    The instability break points which were found on stress-rupture design curves at each test temperature depended on the translation from a transcrystalline to an intercrystalline type fracture, and the break points of vacuum-melted Incoloy T appeared after a longer time than the air-melted alloys.
    It was believed that the strengthening characteristics of vacuum-melted Incoloy T were caused by precipitations in grain boundaries and matrices.
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  • Shigeo WAKAMATSU
    1961 Volume 47 Issue 4 Pages 612-616
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    No satisfactory and reliable method for the determination of metallic iron in basic slag has been available. Although HgCl2 method has found wide. usage in the determination of metallic iron, no application to the determination of metallic iron in basic slag has been re-ported. As part of a program to develop chemical methods of analysis for basic slag, an investigation of the determination of metallic iron by EDTA titration technique was undertaken in the laboratory of Toto Steel Mfg-Co., Ltd.
    In the recommended method, 0.5g of sample in 50ml of ethyl alcohol solution, containing HgCl2 of about 10 times of metallic iron, kept at 60°C for 20mn, to dissolve only metallic iron and leaving the iron oxides, CaO, etc. unattacked regardless of their ratios. Then the solution was filtered and washed with ethyl alcohol, and 10ml of (NH4) 2S2O8 (20%) solution, 2ml of 1 to 1 HCl, and 100ml of water were added to the filtrate. pH of the solution was adjusted to 2.0-2.5, with 50% of ammonium acetate solution and iron (III) was titrated at 40°C with a standard EDTA solution using tiron as an indicator. In this titration, Hg2+ did not interfere.
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  • Isao TANABE
    1961 Volume 47 Issue 4 Pages 617-633
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Kazuo TSUYA
    1961 Volume 47 Issue 4 Pages 634-646
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Seita SAKUI
    1961 Volume 47 Issue 4 Pages 647-657
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • [in Japanese]
    1961 Volume 47 Issue 4 Pages 658-672
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • 1961 Volume 47 Issue 4 Pages 672
    Published: 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • 1961 Volume 47 Issue 4 Pages 673-675,646
    Published: April 01, 1961
    Released: December 22, 2010
    JOURNALS FREE ACCESS
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  • 1961 Volume 47 Issue 4 Pages 676-677
    Published: April 01, 1961
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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