Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 70, Issue 10
Displaying 1-25 of 25 articles from this issue
  • Michio INOUYE
    1984 Volume 70 Issue 10 Pages 1315-1324
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
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  • Mitsuo KAMA
    1984 Volume 70 Issue 10 Pages 1325-1330
    Published: August 01, 1984
    Released on J-STAGE: February 15, 2010
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  • Akira SATO
    1984 Volume 70 Issue 10 Pages 1331-1342
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
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  • Hiroshi MAKI
    1984 Volume 70 Issue 10 Pages 1343-1347
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
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  • Tadashi TAKIMOTO
    1984 Volume 70 Issue 10 Pages 1348-1356
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
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  • Kiminari KAWAKAMI
    1984 Volume 70 Issue 10 Pages 1357-1361
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
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  • Kyoji SATO, Yasunori NISHIKAWA, Yoshinobu UEDA
    1984 Volume 70 Issue 10 Pages 1362-1369
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    An analytical procedure was developed for reduction in fluidized beds with batch-wise iron ore feed based on the bubble assemblage model and the three-interface reaction model with solid-state diffusion. The experimental results of hydrogen reduction in the high pressure fluidized bed were analyzed according to the proposed procedure. The simulated results were able to describe the experimental data up to the final stage in which the reduction rate became extremely low. Effects of pressure, temperature, gas velocity, bed height, and fractional reduction on the reduction rate and the utilization factor for hydrogen were elucidated quantitatively by the proposed analytical procedure.
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  • Hiroyuki TAKASHIMA, Yutaka SUZUKI, Motofumi KAMINAKA, Katsuhiko KABURA ...
    1984 Volume 70 Issue 10 Pages 1370-1376
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    For ignition furnaces of sintering plants, the combustion equipment free from troubles which are caused by coal ash melting has been developed for pulverized coal firing. The developed burner has a high combustion efficiency of fuel with a short stable flame, that is, when coal combustion rate is 30 kg/h and injecting coke oven gas is equivalent to 10% of total heat input of fuel, the flame length is 0.8 m. The developed distributor for pulverized coal has been proved to give a small distribution error of less than ±4%.
    These burners and distributor were attached to an ignition furnace in the Sintering Plant. In comparison with the conventional coke oven gas firing (25 burners), heat input was increased by the change of heat distribution but ignition fuel cost was decreased 40%. Good quality of sintered ore was also achieved.
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  • Akihiro ONO, Naoharu YAMAGUCHI
    1984 Volume 70 Issue 10 Pages 1377-1384
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    A new spectrophotometric method for determination of elemental sulfur in blast furnace slag has been developed. The outline of the procedure is as follows. A slag sample is powdered with n-hexane using a disk mill and elemental sulfur in the sample is extracted into n-hexane at the same time. The ultraviolet absorption of the n-hexane layer is measured at 275 nm to determine the quantity of elemental sulfur.
    By using this method elemental sulfur can be determined with high accuracy, provided the amount is higher than 0.002%. The coefficient of variations at the 0.05 and 0.2% levels of elemental sulfur are 2.3 and 1.4%, respectively. The time required for analysis of one sample is less than 10 min. There is no interference effect for sulfur compounds in the slag sample such as sulfate, thiosulfate, sulfite, sulfide and poly-sulfides.
    When a slag sample is powdered under the dry condition before the n-hexane extraction, lower analytical values are obtained, because elemental sulfur changes into poly-sulfides by the reaction with Ca components of the slag sample. This chemical change is found to be suppressed by simultaneous performance of powdering and extraction. Based on this technique, an analytical method is proposed and successfully applied to determine elemental sulfur in a slag sample.
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  • Kensuke SASSA, Takao CHOH
    1984 Volume 70 Issue 10 Pages 1385-1391
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    In order to find the effect of phosphorus vapor on the gasification of graphite and coke in carbon dioxide, the gasification rates of electrode graphite and metallurgical coke in CO2-CO-Ar gas mixture were measured in the temperature range of 900-1 000°C at atmospheric pressure. The rate of gasification decreased with increasing the partial pressure of phosphorus. Phosphorus was found to have strong retardation effect.
    The experimental result were interpreted by use of Langmuir-Hinshelwood type reaction mechanism (R=k1PCO22/1+k1/k2RCO22+k3PCO+k4Pp) and the rate constants k1, k2 and the adsorption coefficients K3, K4 were obtained as follows.
    For electrode graphite ; k1=exp (17.78-65 851.2/RT) (mol/min · atm· g-c), k2=exp (9.585-24 578/RT) (mol/min · g-c), k3 = exp (-13.74 + 38, 108.3/RT) (atm-1), and K4=exp (-8.53 + 43 235.6/RT) (atm-1), and for metallurgical coke ; k1=exp (20.49-68 350/RT) (mol/min · atm · g-c), k2=exp (5.478-14 405/ RT) (mol/min · g-c), K3 =esp (-8.30 +23 330/RT) (atm-1), and K4=exp (-3.92 +31 704.7/RT) (atm-1).
    Activation energies for k1, with electrode graphite and metallurgical coke are obtained 65.85kcal/mol and 68.35kcal/mol respectively.
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  • Takehide SENUMA, Hiroshi YADA, Yoshikazu MATSUMURA, Shuichi HAMAUZU, K ...
    1984 Volume 70 Issue 10 Pages 1392-1399
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    An accurate estimation of the resistance to hot deformation is one of the most important factors for the gauge accuracy of hot strip sheets. Application of an equation determined by data of single pass deformation to the calculation of the resistance to deformation for high speed continuous hot rolling often causes a considerable error. The main reason for the error lies in the metallurgical phenomena during a multiple deformation process, which are different from those of a single deformation. In this investigation, a new calculation model has been developed which takes the influence of the metallurgical phenomena like recovery and recrystallization on the resistance to hot deformation into consideration. It has been shown that the dislocation density is a suitable quantity which describes the influence of the metallurgical changes on the resistance to hot deformation quantitatively.
    The model has been applied to a high speed continuous hot strip mill and a remarkable improvement in the estimation of the resistance to deformation has been achieved.
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  • Akira MATSUDA, Takahisa YOSHIHARA, Kazuaki MIYACHI, Yasuhiro HIROOKA, ...
    1984 Volume 70 Issue 10 Pages 1400-1406
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    A new electrogalvanizing line started its operation in January, 1982 at Chiba Works, Kawasaki Steel Corporation, which has several excellent characteristics on operation and products such as below mentioned.
    (1) Plating voltage of CAROSEL method with chloride bath is so low as under 10 V for the current density 150 A/dm2.
    (2) Uncoated surface of one-side electrogalvanized product, which is perfectly free from Zn throw-around, has good phosphatability and paintability similar to those of cold rolled product.
    (3) Newly designed counter flow system increases limited current density of Zn plating up to 200 A/dm2.
    (4) Zinc phosphate product has excellent whiteness and good paintability owing to appropriate control of Ni content in the phosphate film.
    (5) Hydrogen quantitative feeding method has been developed for smaller deviation of Cr coating weight and color tone of chromate product. Resin coating on chromate product improves corrosion resistance and antifingerprint property.
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  • Kiyoshi BESSYO, Hisashi YOSHINAGA, Seiichi WATANABE, Masaaki NAKAMURA, ...
    1984 Volume 70 Issue 10 Pages 1407-1413
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    The direct quenching method, as a process of effectively using the heat after rolling is recently gaining interest not only because it saves energy but also because it increases the hardenability of steel. The mechanism of increasing the hardenability of steel, an outline of the manufacturing method of high strength steel plate by roller quenching equipment installed on-line in the plate mill and the characteristic properties of 60 kgf/mm2 and 80 kgf/mm2 high strength steel plates obtained by the direct quenching method are described.
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  • Kanji KAWAGUCHI, Mitsuo KAWAI, Matsuo MIYAZAKI, Osamu WATANABE
    1984 Volume 70 Issue 10 Pages 1414-1420
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    One housing 200 MW class steam turbine requires a rotor with both high temperature creep rupture strength and low temperature toughness.
    A new rotor forging has been investigated in terms of the effects of additional elements (Nb and Ni) and heat treatments on 1Cr-1Mo-0.25V steel creep rupture strength and toughness. The additional elements and differential heat treatment (DHT) showed synergistic improvement in these mechanical properties. Thus, the 1Cr-1Mo-0.25V-Nb-Ni steel can be employed after DHT as rotor material for the one housing 200 MW class steam turbine.
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  • Thoru ISHIGURO, Yoshikuni MURAKAMI, Tadayoshi TSUKEDA, Keizo OHNISHI
    1984 Volume 70 Issue 10 Pages 1421-1428
    Published: August 01, 1984
    Released on J-STAGE: May 07, 2010
    JOURNAL FREE ACCESS
    Recently, the intergranular creep cracking was found at the weld joints of high temperature reactors made by the 1 1/4Cr-0.5Mo pressure vessel steel. The cracking is caused by the fact that the coarse grain region of weld heat affected zone of low creep rupture ductility is located at the stress concentration sites.
    For the purpose of suitable material selections, creep rupture behavior of the synthetic HAZ was studied for various Cr-Mo steels containing 1 to 5% chromium. Both the creep rupture ductility and notched sensitivity of the weld HAZ were found to be remarkablely improved by increasing Cr contents.
    Effects of the Cr content on the rupture ductility were discussed on various metallurgical view points. Some results imply that improved rupture ductility caused by higher Cr contents is attributed to reducing γ/α transformation temperatures, avoiding the formation of high density Mo2C carbides and decreasing the size of grain boundary carbides.
    In order to prevent the creep cracking of the weld Joint, therefore, the application of Cr-Mo steels of higher Cr content is recommended for the pressure vessel used in higher temperatures over 500°C.
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  • Masakazu NIIKURA, Sadahiro YAMAMOTO, Chiaki OUCHI, Isao KOZASU
    1984 Volume 70 Issue 10 Pages 1429-1436
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    The α→γ transformation behavior and its correlation with mechanical properties were systematically investigated in two types of transformation-strengthened steel under a range of very low carbon content from 0.005% to 0.05%. Those are C-high Mn-Nb-B bainite steels and C-high Mn-Mo-Nb acicular ferrite steels. The effects of C content and controlled rolling on the microstructures and mechanical properties were studied, by focusing on the difference between these two steels. The microstructure of bainite steels was recognized as type I upper bainite which was characterized by lath structure of 0.5-1μm width with a retention of austenite grain boundaries in pan-cake shape. Acicular ferrite steels showed a mixed microstructure consisting of polygonal ferrite and upper bainite.
    Transformation behavior and mechanical properties in bainite steels did not change markedly with both C content and the degree of controlled rolling, while they changed remarkably in acicular ferrite steels with those variables. Metallurgical factors controlling the strength and toughness in both steels were discussed in detail.
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  • Yoshitaka IWABUCHI
    1984 Volume 70 Issue 10 Pages 1437-1444
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    It is known that the toughness of 13Cr-3.8Ni cast steel decreases when the steel is tempered at around 550°C and cooled at slow rate. Effects of tempering temperature, holding time and repetition of tempering on toughness deterioration of the steel are investigated by means of metallurgical observation and mechanical test. It is found that toughness decreases with increase of yield strength which accompanies the increase of corrosion loss in 6.0% HNO3 solution. Fracture appearance transition temperature and yield strength tend to decrease with the increase of the degree of tempering, while the amount of austenite increases. Toughness is recovered when the steel is tempered at higher temperatures such as 630°C. From these results it is considered that the deterioration of toughness during tempering is ascribed to the rejection of carbon from reverted austenite during slow cooling and the formation of carbide.
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  • Tsutomu IKOMA, Osamu KOJIMA, Kotaro HATAKEYAMA, Shogo KANAZAWA, Teruo ...
    1984 Volume 70 Issue 10 Pages 1445-1451
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    New steels HT60 whose goal is weight reduction, rationalization of fabrication and construction of power transmission tower are developed. In hot dip galvanizing process, weld heat affected zone cracking occurs occasionally due to liquid zinc embrittlement of steel. The larger the scale of fabricated sub-assembly for hot dip galvanizing, the larger is the thermal stress arised during the process. Improvement of susceptibility to liquid zinc embrittlement becomes, then, more important in development of new steels to be employed for larger scale tower.
    This report describes 1) an estimation of weight reduction of tower by employing HT60 steels, 2) establishing test methods for assessment of liquid zinc embrittlement of steel, 3) effect of alloying elements on liquid zinc embrittlement of steel, and 4) properties of steel pipes, plate and flange developed based on the results of studies above mentioned.
    New steels HT60 have satisfactory mechanical properties and weldability together with low susceptibility to liquid zinc embrittlement, and are favorable for the large scale power transmission tower application.
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  • Hiroshi NOGUCHI, Tomoo TANAKA, Kooichi KAWAMOTO, Sumio UMEMOTO
    1984 Volume 70 Issue 10 Pages 1452-1458
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    Wear properties of high-chromium and adamite roll materials have been investigated by using roll wear machine designed to simulate the working conditions of a roll at high temperatures. It has been shown that high-chromium roll materials have better wear resistance than adamite roll materials. The use of the highchromium rolls for work roll in the primary stand of hot strip mill finishing train decreased roll cost without deteriorating surface of hot strip.
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  • Takashi ABE, Tetsuya SAMPEI, Hirotada OSUZU, Isao KOZASU
    1984 Volume 70 Issue 10 Pages 1459-1466
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    Despite of ferrite pearlite structure, microalloyed and controlled rolled bar revealed good fatigue property almost equivalent to quenched and tempered plain carbon steels whose microstructure was tempered martensite. Detailed study was carried out to give a comprehensive interpretation for this phenomenon. The relation between static strengthening mechanisms and fatigue property was investigated quantitatively, using low and medium carbon steels conventionally or controlled rolled with variation of Si and Mn contents and V or Nb additions. As a result of this, it was clarified that each strengthening mechanism showed different contribution in improving fatigue limit. Compared with grain refinement, pearlite and dislocation strengthening, both solid solution and precipitation strengthening improved fatigue limit efficiently as well as dispersion strengthening. This was caused by their effectiveness both in preventing dislocation from migration under cyclic loading and in strengthening ferrite matrix comparatively uniformly.
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  • Seiji SUZUKI, Toshihiro TAKAMURA
    1984 Volume 70 Issue 10 Pages 1467-1473
    Published: August 01, 1984
    Released on J-STAGE: February 15, 2010
    JOURNAL FREE ACCESS
    This investigation deals with the mechanism on the formation of white line in welded joints of ERW steel pipes. In order to demonstrate the formation mechanism, the difference in carbon contents between weld line and extruded melting bead in simulated resistance welded joints was investigated in detail, using hypoeutectics, eutectics and hypereutectics in Fe-C alloys.
    In hypoeutectics, the carbon content in weld line is lower than that in base metal, while the carbon content in extruded melting bead is higher. On the other hand, the carbon content in weld line is higher than that in base metal and the carbon content in extruded melting bead is lower in hypereutectics. No difference in carbon content occurs between weld line and extruded melting bead in eutectics.
    It can be deduced from these results that two phase region where solid and liquid phase coexist exists in weld line, and the liquid phase coexisting with solid phase is extruded outward and the solid phase remains in the weld line at upsetting. Thus, it can be concluded that the difference in the content of alloying elements between solid phase and liquid phase leads to the formation of white line in resistance welded joints such as ERW steel pipes.
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  • [in Japanese], [in Japanese]
    1984 Volume 70 Issue 10 Pages 1474-1477
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
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  • [in Japanese], [in Japanese]
    1984 Volume 70 Issue 10 Pages 1478-1481
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1984 Volume 70 Issue 10 Pages 1493-1495
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
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  • [in Japanese], [in Japanese], [in Japanese]
    1984 Volume 70 Issue 10 Pages 1495-1495,1500
    Published: August 01, 1984
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
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