Tetsu-to-Hagane

[title in Japanese]

[in Japanese]

1970 Volume 56 Issue 10 Pages 1299-1300
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1299

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Reduction of Iron Ore at Temperatures above 900°

Fusatoshi EMOTO, Mitsuru TATE

1970 Volume 56 Issue 10 Pages 1301-1310
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1301

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For the purpose of clarifying the mechanism of the reduction of iron are in the high temperature range from 900°C to 1 450°C, the rate of reduction by CO gas with and without the presence of coke was studied.
In the case of reduction by CO gas only, the rate increased with the increase of temperature, but it became smaller when are or pellet began to fuse.
The rate of reduction was remarkably accelerated by solid coke when are or pellet fused, however, this effect of coke was weak when it remained in the solid state.
The rate of reduction by CO gas when temperature was raised with time was also studied and it was found that there were functional relations between heating velocity and reduction rate in the temperature rangefrom 900deg;C up to the fusion temperature. When the temperature was changed linearly with time, the degree of reduction increased linearly with temperature.
A specially designed thermobalance with strain gauge was employed in this study.

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Theoretical Analysis on the Dynamic Characteristics of Blast Furnace in the Region between Melting Zone and Tuyere Level

Masayuki HORIO, Iwao MUCHI

1970 Volume 56 Issue 10 Pages 1311-1322
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1311

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A mathematical model for analysing the dynamic characteristics of blast furnace in the region between melting zone and tuyere level are developed in this paper. On the basis of this model, the fundamental informations on the responses of both the location of melting zone and temperature of molten materials at the tuyere level to the step changes of blast temperature, steam ratio, blast volume and oil-injection rate have been obtained with the aid of digital computer.
Three principal time constants, i. e., time constant concerning the accumulation of materials in melting zone, one related to the accumulation of heat in coke zone supposedly located below melting zone and one connected with the shifting process of melting zone, have been taken into account in the analysis. It has been found that the shifting process of melting zone affects severely on the dynamic behavior of blast furnace, since the time constant connected with this process becomes large value such as several hours.

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Study on Solidification of Heavy Steel Ingots

Kiichi NARITA, Takasuke MORI

1970 Volume 56 Issue 10 Pages 1323-1341
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1323

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Solidification processes of heavy steel ingots are analogized by using computer, and internal structure is discussed in connection with distribution of chemical elements, equi-solidus line, freezing rate (velocity of averaged advancing solidus line) and staying time (staying time between liquidus and solidus temperature). The results are as follows:
1) An intimate relation is seen among the internal structures, freezing rate and its distribution.
2) Inverse V segregation appeared mainly in the zone with positive acceleration of freezing rate. This means that the segregation take place in granular crystal zone as well as in equi-axial crystal zone.
3) The pouring temperature appears to have a great influence on internal structures. In discussing the internal structures, therefore, a good care must be paid on the difference between the pouring temperature of liquid steel and the solidus temperature which is subject to the chemical composition.
4) The internal structures along an equi-time solidus line differ in top side and bottom side. There are branched columnar crystals in the top part, equi-axial crystals in the middle part and granular crystals on the bottom parts of 20t ingot along the 2 hr-solidus line after pouring.
5) The last solidifying zone (V segregation zone) shows the gourd-like-shape, which is obviously affected by the electric arc hot-topping, and then fine equi-axial crystals or granular crystals are formed at the bottom.

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Structure of Rust Layer Formed on Atmospheric Corrosion Resistant Steels

Masamichi KOWAKA, Jiro SATAKE, Taishi MOROISHI, Nobukatsu FUJINO

1970 Volume 56 Issue 10 Pages 1342-1351
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1342

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The distribution of elements in rust layer formed on low alloy steels after various periods of exposures in industrial and rural atmospheres was investigated by means of microscopic examination and electron probe microanalysis. The rust layer in large pits contains Cu, P, and Cr in a localized state. Cr and P concentrate around such defects in the rust as voids and cracks. The local concentration of Cu seems to diminish as the exposure period becomes longer. The rust layer on the flat surface surrounding large pits and also the surface layer above large pits have shown no evidence of localized concentration of Cu and P and are characterized by the fact that little Cr content is found in the rust. Si, main constituent of dusts, has been found in these parts of the rust, but none in the pits. It is supposed that Cr, P, and Cu produced by corrosion reaction presumably form far less soluble compounds than ferrous ion and are likely to precipitate in the pits while ferrousion diffuses out from the pits and precipitates on outer surface.

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Metallographic Analysis of Vanadium in High Strength Steel

Shigeo WAKAMATSU

1970 Volume 56 Issue 10 Pages 1352-1364
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1352

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A simple and accurate method has been developed for the metallographic analysis of vanadium in high strength steel.
1. Separation of vanadium compound from steel.
(a) The steel sample covered with close-texture filter paper as a diaphragm and connected as an anode, is dissolved into 100 to 130ml of 1% NaCl-5% EDTA electrolyte (pH 6-7) with current density of 50 mA/cm² for 1 to 2 hr. Remove the anode, and residue is collected into the filter paper. To the residue and filter paper add 50ml of HCl (1: 4), and pass in a stream of air for 30 min at room temperature.
(b) Filter and wash with water. Add 5ml of HNO₃ and 10ml of HClO₄ to the filterate and evaporate to dense white fumes, cool, dilute to 50ml and determine vanadium as (Fe, V) ₃C in accordance with section 2.
(c) Add 30ml of HNO₃ and 20ml of HClO₄ to the electroyte and evaporate to dense white fumes, cool, dilute to 100ml, and determine vanadium as solid solution in accordance with section 2.
(d) Transfer the paper and residue (paragraph (b)) to a beaker, add 30ml of HCl (1:1) and boil for 5 min.
(e) Filter and wash with water. Add 5ml of HNO₃ and 10ml of HClO₄ to the filterate and evaporate to dense white fumes, cool, dilute to 50ml, and determine vanadium as V₂O₃ in accordance with section 2.
(f) Transfer the paper and residue (paragraph (e)) to a beaker, add 40ml of HNO₃ (1:3), and boil for 5 min.
(g) Filter and wash with water. Add 10ml of HClO₄ to the filterate and evaporate to dense white fumes, cool, dilute to 50ml, and determine vanadium as V₄C₃ in accordance with section 2.
(h) Transfer the paper and residue (paragraph (g)) to a beaker, add 30ml of HNO₃ (1:1) and 5ml of H₂O₂ and boil for 10 min.
(i) Filter and wash with water. Add 10ml of HClO₄ to the filterate and evaporate to dense white fumes, cool, dilute to 50ml, and determine vanadium as VN in accordance with section 2. Discard the residue.
2. Photometric determination of vanadium.
Transfer 20ml of each of solutions (section 1.(b), (c), (e), (g) and (i)) to separatory funnels, add 2ml of copper solution (0.5%) and 1 drop of KMnO₄ solution (1%), and let stand for 5min. Add 15ml of N-benzoylphenylhydroyxylamine chloroform solution (0.067%) and 10ml of HCl (2:1), and shake for 30 sec. Measure the absorbance of organic phase against chloroform at 530mμ.

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Superlattices in Iron-Base Alloys (Structures and Mechanical Properties)

Soji NENNO, Toshio SABURI

1970 Volume 56 Issue 10 Pages 1365-1382
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1365

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Application of Electron Diffraction to Magnetic Analysis

Shigeto YAMAGUCHI

1970 Volume 56 Issue 10 Pages 1383-1395
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1383

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Toward New Relationship between Iron & Steenndustries and Steel Market

Kenkichi TOSHIMA

1970 Volume 56 Issue 10 Pages 1396-1400
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1396

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Properties of Oxide Strengthening Alloys

Yunoshin IMAI

1970 Volume 56 Issue 10 Pages 1401-1405
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1401

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On the Hexagonal Carbide V₂C Precipitated in Austenitic Steels

Ryohei TANAKA, Takayuki SHINODA, Tomoyuki ISHII

1970 Volume 56 Issue 10 Pages 1406-1408
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1406

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Hexagonal carbide V₂C has never been found in steel.
The present authors, however, found that this carbide was precipitated in 16% chromium-12% nickel-0.12% carbon austenitic steels containing vanadium by the electron microscopic and electron diffraction methods.
The carbide V₂C had lattice constants of a=2.8 Å and c=4.5 Å, and axial ratio c/a of about 1.6, and dispersed as small grain-like particles, near by carbide M₂₃C₆ which precipitated in grain boundary.
The precipitation of the V₂C carbide was found to occur only in the steels with a comparatively low value of V/-(C+ N) atomic ratio, and the carbide seemed to be a transitional phase since it disappeared after a prolonged heating.

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[title in Japanese]

[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...

1970 Volume 56 Issue 10 Pages 1409-1434
Published: September 01, 1970
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1409

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[title in Japanese]

1970 Volume 56 Issue 10 Pages 1435-1444
Published: September 01, 1970
Released on J-STAGE: December 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.56.10_1435

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