鉄と鋼
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
71 巻, 9 号
選択された号の論文の18件中1~18を表示しています
  • 藤本 盛久
    1985 年 71 巻 9 号 p. 1059-1069
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
  • 椿野 晴繁, 山川 宏二
    1985 年 71 巻 9 号 p. 1070-1076
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
  • 岸 輝雄, 大友 暁, 横井 信
    1985 年 71 巻 9 号 p. 1077-1084
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
  • 館 充
    1985 年 71 巻 9 号 p. 1085-1093
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
  • 片山 博, 徳田 昌則
    1985 年 71 巻 9 号 p. 1094-1101
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
    Synthetic FeCr2O4 and MgCr2O4 were reduced by graphite powder under various conditions of temperature and gaseous atmosphere. The kinetic data were analyzed by the use of the rate equation offered by E. T. TURKDOGAN et al. for the oxidation of carbon with gaseous CO-CO2 mixture.
    In the carbothermic reduction of FeCr2O4, the rate was clarified to be mainly controlled by the BOUDOUARD reaction process, which was accelerated to a great extent by the metallic and carbide phases formed. On the other hand, the reduction rate of MgCr2O4 appeared to be mixed-controlled by the BOUDOUARD reaction and gaseous reduction processes.
    Furthermore, the rate-determining process in the carbothermic reduction of more complicated chromites and chromite ores was examined on the basis of the rate constants for the carbothermic reduction of FeCr2O4 and Cr2O3. As the result, it was clarified that the reduction rate of those chromites, especially of Al2O3-containing chromites is mainly controlled by the gaseous reduction process of the chromite particle.
  • 小林 睦弘, グーデナウ H.W., ブルヒャード W.G., シェーファー H.C.
    1985 年 71 巻 9 号 p. 1102-1109
    発行日: 1985/07/01
    公開日: 2010/05/25
    ジャーナル フリー
    Some iron ores were reduced by CO gas in a modified scanning electron microscope equipped with a temperature and gas control; iron precipitates during the reduction were directly observed. Growing mechanism of such precipitates was discussed on their growth in vertical and horizontal directions: the vertical growth is caused by precipitation of supersaturated iron ions under an iron nucleus, which is consequently pushed out toward a free space; while the horizontal one by precipitation of iron ions at a three-phase boundary of precipitated iron, wustite and gas where they were produced. The typical fibrous iron was represented as the result of predominant vertical growth. Very long, fine and dense fibrous iron which appeared in a sulfur-bearing atmosphere was speculated to be attributed to inhibition of the sulfur from the three-phase boundary reaction.
  • 森 一美, 平沢 政広, 新貝 元, 圃中 朝夫
    1985 年 71 巻 9 号 p. 1110-1116
    発行日: 1985/07/01
    公開日: 2010/01/19
    ジャーナル フリー
    A kinetic study has been investigated on the reaction between molten Cu-0.1%Si alloy and a Li2O-SiO2-Al2O3-FeO slag. The explored reaction was Si+2FeO=SiO2+2Fe. The metal-slag melt was stirred by an alumina rod. The experimental temperature was 1250°C.
    In one series of experiments, initial FeO contents of slag were varied from 5 to 15% at a constant rotational speed of the stirrer (200 rpm). The rate data could be represented apparently by linear relationship between log[%Si] and the time (t). Apparent mass-transfer coefficients of Si in metal, k'Si, were calculated. At initial FeO contents, (%FeO)0, below 9%, the reaction rate is controlled both by Si transport in the metal phase and Fe0 transport in the slag phase. At (%FeO)0_??_9%, the reaction rate is controlled only by Si transport in the metal phase.
    In another series of experiments, the stirring speed was varied as 70400 rpm at (%FeO)0=9%. The mass-transfer coefficients, k'Si, were found to be proportional to the 0.5 power of rpm of the stirrer. This experimental finding can be ascribed to the fact that the reaction is of mass-transfer controlled.
    The present reaction system has been established as a suitable model for the purpose of investigating the role of stirring in slag-metal reactions at high temperatures.
  • 別所 永康, 谷口 尚司, 菊池 淳
    1985 年 71 巻 9 号 p. 1117-1124
    発行日: 1985/07/01
    公開日: 2010/01/19
    ジャーナル フリー
    Characteristics of bubble dispersion and fluid flow in a gas-stirred vessel have been studied.
    Nitrogen gas was injected into water through a 0.6 cm diameter nozzle at the center of the bottom of 0.29 m diameter acrylate vessel. Flow patterns were visualized by using insoluble salt particles dispersed in water. In order to simulate the flow patterns, the "bubble dispersion model" is proposed. This model consists of equations of flow and bubble dispersion with constant values of effective kinematic viscosity, υe, and effective dispersion coefficient of bubbles, De. The values of De are assumed to be equal to those of υe and are calculated by the ad hoc model proposed by SPALDING et al.
    The computed flow patterns were roughly consistent with the observed results in the range of qG=1.67×10-51.67×10-4 m3/s and z1=0.10.4 m, where qG is the gas flow rate and z1 is the height of water.
  • 尾野 均, 桝井 為則, 森 久
    1985 年 71 巻 9 号 p. 1125-1131
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
    Recently, it is clarified that dephosphorization of hot metal by lime injection with oxygen is more effective than usual dephosphorization with nitrogen. Then the authors made dephosphorization tests by lime injection to compare two kinds of injection gas (N2 and O2), and discussed the dephosphorization reaction on each condition.
    As a result, following items were clarified. The rate of dephosphorization by lime injection is mainly dependent on oxygen feeding rate and slagging rate of lime. So the rate of dephosphorization by O2 injection is larger than that by N2 injection.
    Therefore, it is desirable to adopt a lime injection with O2 gas to increase the reaction rate and to decrease the consumption of lime.
    Then, it becomes a subject of discussion that decarburization is accelerated by O2 injection. However, it is possible by use of mixed gas of N2 and O2 to control the decarbuization rate and dephosphorization rate to a certain extent.
  • 井上 肇, 浅井 滋生, 鞭 巌
    1985 年 71 巻 9 号 p. 1132-1139
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
    Investigation on V-type segregation is now a crucial subject not only in the production of large size ingots but also in the process of continuous casting with electromagnetic stirring.
    To clarify the formation mechanism of V-type segregation, marked V-type segregations are made in the cold model experiment by use of NH4Cl aqueous solution. The formation mechanism of V-type segregation is considered to consist of the following two processes, namely (1) the formation process of fissures caused by slipping phenomena of equiaxed crystals and (2) the growing process from fissures to V-type segregations. The former induces the V-type slip lines in equiaxed zone and the latter makes V-type channel segregation.
    The slipping phenomena in equiaxed zone are theoretically analyzed on the basis of powder mechanics and the calculated shapes of slip lines are compared with the shapes of V-type segregation observed in the cold model experiments.
  • 国重 和俊, 長尾 典昭, 松岡 孝, 浜松 茂喜
    1985 年 71 巻 9 号 p. 1140-1146
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
    Hot strip mills can be used for thermo-mechanically treating steels through various processing parameters of rolling and coiling. A laboratory simulation was carried out to study the relationship between the coiling temperature, microstructure, and mechanical properties of controlled rolled Ti-bearing steel. Decrease of a coiling temperature from 600°C to a low temperature such as 400°C significantly improved formability as well as low temperature toughness with a small change in strength.
    This type of steel is strenghened mainly by TiC precipitation before coiling, especially during controlled rolling. The steel coiled conventionally at 600°C is strengthened further by additional TiC precipitation during slow cooling after coiling, while the steel coiled at about 400°C is hardened by bainite transformation instead of by such TiC precipitation. The bainite strengthening is responsible for improving formability and low temperature toughness.
    The laboratory studies have led to the success in the production of 80 kgf/mm2 grade Ti-bearing steel with excellent formability and low temperature toughness.
  • 藤岡 康夫, 室 博
    1985 年 71 巻 9 号 p. 1147-1154
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
    A new machining process, called auscutting, has been developed, in which the cutting operation is made in supercooled austenite state during quench cooling. To control the cutting conditions and lengthen the tool life, the cutting temperature is measured in this process by a tool-work thermocouple method. The black ceramic tool (Al2O3+TiC) used has some electric conductivity and the black ceramic-bearing steel thermocouple exhibits the thermo-e.m.f. of about 1 mV/100°C. The influence of cutting conditions on the cutting temperature and the microstructure of chips is investigated.
    The results obtained are summarized as follows:
    (1) The cutting temperature in auscutting is about 200°C higher than that in usual cutting process for the annealed steel and reaches 1100°C at the cutting speed of 200 m/min and the feed of 0.2 mm/rev.
    (2) The chip disposability is very good, because the chips are saw-toothed and hardened after cooling to room temperature.
  • 古林 英一
    1985 年 71 巻 9 号 p. 1155-1162
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
    本研究の内容を要約すると次のとおりである.
    (1)純銅型圧延集合組織を有するオーステナイトを変態させた時の変態集合組織をモンテカルロ法により計算機シミュレーションを行つた.従来の実験結果から上記条件に符合する典型的{001}極点図を選び,これまで知られているバリアント選択則をもとにした計算極点図と比較した.
    (2)バリアント選択がないと仮定した計算極点図の極点分布は,実測極点図の極密度分布より広い範囲を含み,バリアント選択の存在が示唆された.
    (3)バリアント選択則の一つとして,圧延による外力がオーステナイトのすべり系に及ぼす効果をもとにした活動すべり系モデルと晶癖面モデルを用いた計算では,実測結果をうまく説明できない.これに対してオーステナイトの{111}<112>せん断変形で,変形双晶の生ずる向きに対する圧延と逆向きの「圧延逆応力」の助けを仮定した計算と実測結果は比較的良く合致する.
  • 岩渕 義孝, 畔越 喜代治, 竹之内 朋夫, 宮本 剛汎
    1985 年 71 巻 9 号 p. 1163-1169
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
    Since the type 13Cr-Ni steels are easily hardened, hardness of the weldment rises without suitably post-weld heat treatment. Therefore, experiments have been made to study the effect of hardness on fatigue behavior in 13Cr-4Ni steel casting by using welded joints and as-quenched specimens. The results obtained are as follows;
    (1) Maximum hardness at heat-affected zone is markedly dependent upon carbon content in as-welded condition.
    (2) There is little difference between base metal and weld for fatigue strength of notched and smooth bar specimens in water.
    (3) Hardness and amount of retained austenite across the weldment are affected by heat cycles during the welding.
    (4) No effect of hardness levels on fatigue strength is observed in smooth and notched bar specimens.
    (5) Fatigue strength can be estimated from the modified GOODMANN diagram when the mean stress is applied.
  • 青木 孝夫, 中野 恵司, 福原 煕明, 岡田 明, 小林 志希男, 木村 勝美, 稲垣 道夫
    1985 年 71 巻 9 号 p. 1170-1177
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
    The sizes of planar defects in the butt welded joints of a high tensile steel were measured by ultrasonic testing with a point focussed angle probe, and the results were related to the fatigue and corrosion fatigue life predictions for the joints containing those defects. Surface and buried lack of penetration, and pear-shaped bead hot crack were artificially made in the welded joints by the control of gas metal arc welding conditions. The fatigue and corrosion fatigue life curves for the defective specimens were predicted by fracture mechanics technique using the fatigue crack growth data of weld metal measured in air and those of base metal in saltwater reported previously. Reasonably close agreement between the predicted and observed values was obtained for both the cases in fatigue and corrosion fatigue, and hence it was concluded that sufficiently accurate fatigue and corrosion fatigue life predictions would be possible provided the defect shape was detected with the accuracy of about ±1 mm as was done in this study.
  • 小林 俊郎, 若井 直人, 八木 渉, 梶野 利彦, 上田 俶完
    1985 年 71 巻 9 号 p. 1178-1185
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
    The mechanical properties such as strength, ductility, and toughness were examined in static- and dynamic-tensile tests, V-notched Charpy impact test, and dynamic fracture toughness (J-integral) test for three sorts of steels with the ausform of 25% rolling: (steel A) Fe-0.3C-9Cr-8Ni-4Mo-2Mn, (steel B) Fe-0.3C-9Cr-8Ni-4Mo-10Mn, and (steel C) Fe-0.3C-9Cr-12Ni-4Mo-10Mn.
    For steel A, besides the usual TRIP in a narrow sense caused by the deformation induced α'-martensite, a different type of TRIP in a wide sense was observed in the static tensile test, which was due to the substructure such as stacking fault and mechanical twin. In dynamic tensile test and Charpy impact test for steel A, TRIP slightly occurred.
    For steels B and C, TRIP in a wide sense alone occurred in the tests because of stabilization and low stacking fault energy of austenite matrix by high Mn content. High Mn TRIP steels provided an excellent dynamic fracture toughness.
  • 中野 正則, 大塩 昭義, 大久保 正, 近藤 伸彦, 大橋 章一, 吉原 一紘, 岸本 哲, 西野 真
    1985 年 71 巻 9 号 p. 1195-1197
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
  • 辻川 茂男
    1985 年 71 巻 9 号 p. 1268
    発行日: 1985/07/01
    公開日: 2009/06/19
    ジャーナル フリー
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