Tetsu-to-Hagane

[title in Japanese]

[in Japanese]

1969 Volume 55 Issue 1 Pages 1-2
Published: January 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_1

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1968 Perspective of Production and Technique of Iron and Steel in Japan

Takeshi YAMAOKA

1969 Volume 55 Issue 1 Pages 3-12
Published: January 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_3

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Influence of the Flow Rate of Gas on the Rate of Reaction between Molten Iron and Gas

Koin ITO, Kokichi SANO, Shunsuke ARINO

1969 Volume 55 Issue 1 Pages 13-19
Published: January 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_13

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Experiments were done on the rate of decarburization of molten iron with CO₂-Ar mixtures. The rate of reaction at the whole surface of melt varied almost proportionally to the flow rate of gas, but deviated remarkably from the linear relation at high flow rates. If the blowing tube approached to melt, the rate of reaction increased. When the interface area was changed with magnesia ring of i.d. 2r, the rate of reaction was proportional to r₃ but not to r². When the velocity of gas stream was high, it was clarified that the outer parts of metal surface attributed hardly to decarburization. A linear relation was found between the flow rate of gas and the rate of decarburization per unit area of melt at the front of the blowing tube. As the results, it seems probable that the difference of attribution in different localties to the proceeding of reaction is caused by the difference of velocity of gas stream at different localties at the interface. Variations of the rate of decarburization were also tried to be explained by means of the gas boudary layer theory.

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On the floating-up Velocity and the Loagulability of the Primary

Products in Si-Deoxidation in a Static Iron Bath

Saburo KOBAYASHI, Hisashi NISHIUMI

1969 Volume 55 Issue 1 Pages 20-26
Published: January 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_20

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For the deoxidation of iron melt with silicon, a study has been made to investigate the floating-up velocity of the particles of the primary product in the static iron bath and the coagulation of them on the way of floating-up.
The results obtained are as follows;
1) The floating-up velocity of the particles of the primary product consisting of components SiO₂ and FeO obeys better a velocity equation υ= (3/2)(Δρg/18η) x² rather than Stokes' equation υ= (Δρg/18η) x², where x is radius of a particle.
2) The so called “local reaction heat effect” is possible to stimulate thegrowth of the primary products by coagulation in the early period of deoxidation. Therefore, when the amount of reactant or added silicon is large which would increase the heat effect, and the agitation is strong, the number of coarse particles will increase.
As a result, the separation of the primary product from the bath becomes more rapid with the increase of added silicon.
3) When the amount of added silicon is small, the coagulation of the products is poor in the early period of deoxidation because of the small heat effect. However, the separation of the products is as rapid as in the case of the large amount of added silicon, for there issome composition range favourable for the coagulation on the way of floating up in the bath.
4) The amount of added silicon does not essentially affect the floating-upremoval rate of the primary product in high silicon range.
5) When the concentration of the suspension of the inclusion particles in the bath is high, all the particles contribute almost equally to the coagulation on the way of floating up independently of radii.
6) In case that the primary deoxidation products are some oxide mixtures, the constitution of chemical composition of the particles has a considerable influence on the floating-up removal rate from the bath.

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Anisotropic Behaviors of Prestrained Sheet Steels and Subsequent Formability

Kiyota YOSHIDA, Kunio MIYAUCHI, Susumu MIZUNUMA

1969 Volume 55 Issue 1 Pages 26-47
Published: January 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_26

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The development of planar anisotropy and the abrupt change in the mechanical properties of sheet steels (four Al-stabilized and one rimmed) due to the increase of prestrain are investigated in relation to the variation of crystallographic texture for different prestraining modes of uniaxial tension, biaxial tension, tension-compression, and bending-unbending.
The mechanical properties of those variously prestrained sheet steels may be explained more reasonably by employing the latent workhardening theory in a macroscopic deformation model having the active and latent slip systems resolved into width and thickness components in addition to the information from the variation of pole figure.
A concept of “re-formability”, the formability of prestrained sheet metal having a certain deformation texture developed in it, is proposed for more systematic understanding of press formability, where it is distinguished from the ordinary or primary formability of sheet metal in terms of the variation of deformation path from the first forming to the subsequent one.
The variation of mechanical properties including the r value during the first forming of monotonic deformation path is generally increased by increasing the difference in the mode of deformation between the first forming and the subsequent one, and also by increasing the difference between the strain ratio (r value) of the virgin material and that forcedly given in the first forming, that is, the difference between the preferred orientation of sheet metal and the stable end orientation in the forming.

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Study on Precipitation Hardening of Martensitic Fe-Ni-Be Alloys

Masao KANAO, Toru ARAKI, Hideo NUMATA, Keishi NAKANO

1969 Volume 55 Issue 1 Pages 48-58
Published: January 01, 1969
Released on J-STAGE: December 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_48

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Age hardening behaviours and precipitation process of martensitic Fe-5%Ni-Be alloys were investigated. The results obtained were as follows:
(1) Fe-5%Ni-Be alloys containing 0.47%Be or above were remarkably hardened by aging in the temperature range between 400°C and 550°C after water-quenched from austenite region.
(2) There were two types of equilibrium precipitates in the aged alloy. One was finely distributed general-type precipitate, and the other was stringer-like one produced by grain boundary reaction. Both of them were C_sCl type NiBe having lattice parameter of about 2.62Å. The reaction was suppressed by the addition of small amount of Ti or Zr, accompaniedby significant improvement of hardening.
(3) Through the transmission electron microscopy and X-ray diffraction analysis, . it is considered that the alloys are hardened by the formation of clusters with ordered structure rich in solute arom on the matrix lattice.
(4) General-type precipitates were formed with the same orientation as the bcc martensite matrix. However, as the misfit of the two bcc lattices was relatively large, the coherency strain and in the lattice was possibly lost and the specimen was over-aged by the precipitation. Double diffraction phenomenon was often observed on the diffraction patterns from the precipitated specimens.
(5) Fe-5%Ni-Be alloys showed reversion phenomenon when they were re-heated for short period at e. g. 625°C after pre-aged for 7hr at 450°C.

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Oxygen Converter/DM (Duo Vortical Mixing) Steelmaking

Kiichi NARITA, Akitu TOMITA, Sinji KOYAMA, Takamiti ITO, Yasuo HIROOKA

1969 Volume 55 Issue 1 Pages 59-68
Published: January 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_59

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The DM reversible shaking of a vessel is very effective for mixing the melt with slag owing to the active mixing action (duo vortical mixing) compared with the Kaldo and Rotor processes.
An investigation was made on the refining reaction which resulted from the combination of slag-metal reaction by DM operation and gas-metal reaction by LD operation in one vessel.
In the LD/DM combined process, the respective conditions of oxygen blowing and duo vortical mixing can be independently varied. The experiments under various conditions were to find the optimum condition for rapid refining to low phosphorous steel.
The conditions of experiments were as follows:
Using one-slag practice,
i) simultaneous operations of LD and DM,
ii) simultaneous operations of LD and DM, followed by LD operation only, and
iii) LD operation only, followed by the simultaneous operations of LD and DM.
Using two-slag practice,
i) simultaneous operations of LD and DM, followed by LD operation only, and
ii) LD operation only, followed by simultaneous operations of LD and DM.
The experimental results were as follows:
1. The rate of dephosphorization during the LD/DM operation in the first stage of refining was two times as rapid as that during only the LD operation in the same stage.
2. The dephosphorization during the LD/DM operation in the first stage of refining proceeded prior to the decarburization. For example, phosphorous content in bath decreased to 0.003 to 0.004% at 2% carbon in bath.
3. It was proven that the control of refining reactions of the melt could be made by optional combination of the conditions between oxygen blowing and duo vortical mixing in the case of the LD/DM operations.

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On the Substitutional Solid-Solution Strengthening in Iron Alloys

Shin TAKEUCHI

1969 Volume 55 Issue 1 Pages 69-83
Published: January 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_69

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My Attachment for Iron-and Steel-Making Technique

Eiji MUNEKATA

1969 Volume 55 Issue 1 Pages 84-89
Published: January 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_84

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Recent Buildings and their Effect on Steel

Hajime UMEMURA

1969 Volume 55 Issue 1 Pages 90-93
Published: January 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_90

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New Electrolyte for Electrolytic Isolation Method

Shigeo WAKAMATSU

1969 Volume 55 Issue 1 Pages 94-95
Published: January 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_94

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An electrolytic solution containing 1% NaCl-3 to 5% EDTA solution is used as a new electrolyte in the electrolytic isolation for the metallographic analysis of steel.
The steel sample, which is covered with filter paper, is connected as an anode, and is dissolved in 100ml of NaCl-EDTA electrolyte at current density of 50mA/cm₂ for 2 to 4hr. A residue of carbide, nitride, oxide and other impurities can be collected in the filter paper, and is separated and analyzed by a chemical procedure as directed in previous papers. To the electrolyte, HNO₃, HClO₄ and H₂SO₄ are added, subsequently, it is evaporated to dense white fumes, and then the elements as solid solution are determined by a photometric method. Quantitative recovery of sulfides in carbon steel is obtained by use of NaCI-EDTA electrolyte.

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[title in Japanese]

1969 Volume 55 Issue 1 Pages 96-99
Published: January 01, 1969
Released on J-STAGE: December 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.1_96

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