Tetsu-to-Hagane

Structural Steel and Steel Construction

Morihisa FUJIMOTO

1985 Volume 71 Issue 9 Pages 1059-1069
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1059

JOURNAL FREE ACCESS

Download PDF (5294K)
Hydrogen Attack of Steels

Harushige TSUBAKINO, Koji YAMAKAWA

1985 Volume 71 Issue 9 Pages 1070-1076
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1070

JOURNAL FREE ACCESS

Download PDF (1295K)
Report on Committee of the Evaluation of Structural Materials

Teruo KISHI, Akira OHTOMO, Shin YOKOI

1985 Volume 71 Issue 9 Pages 1077-1084
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1077

JOURNAL FREE ACCESS

Download PDF (1357K)
Report on Ironmaking Technology in Post-war Japan by Professor T. L. JOSEPH

Mitsuru TATE

1985 Volume 71 Issue 9 Pages 1085-1093
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1085

JOURNAL FREE ACCESS

Download PDF (1579K)
Rate-determining Process in Carbothermic Reduction of Chromites

Hiroshi G. KATAYAMA, Masanori TOKUDA

1985 Volume 71 Issue 9 Pages 1094-1101
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1094

JOURNAL FREE ACCESS

Show abstractHide abstract

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.

View full abstract

Download PDF (987K)
Fibrous Growth of Iron Precipitates during Reduction of Iron Ores by CO Gas

Mutsuhiro KOBAYASHI, Heinrich W. GUDENAU, Willy G. BURCHARD, H. Christ ...

1985 Volume 71 Issue 9 Pages 1102-1109
Published: July 01, 1985
Released on J-STAGE: May 25, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1102

JOURNAL FREE ACCESS

Show abstractHide abstract

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.

View full abstract

Download PDF (10695K)
Mass-transfer in a Slag-Molten Copper Reaction System of Si Oxidation

Kazumi MORI, Masahiro HIRASAWA, Motoshi SHINKAI, Asao HATANAKA

1985 Volume 71 Issue 9 Pages 1110-1116
Published: July 01, 1985
Released on J-STAGE: January 19, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1110

JOURNAL FREE ACCESS

Show abstractHide abstract

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.

View full abstract

Download PDF (1106K)
Fluid Flow in a Gas-stirred Vessel

Nagayasu BESSHO, Shoji TANIGUCHI, Atsushi KIKUCHI

1985 Volume 71 Issue 9 Pages 1117-1124
Published: July 01, 1985
Released on J-STAGE: January 19, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1117

JOURNAL FREE ACCESS

Show abstractHide abstract

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, υ_e, and effective dispersion coefficient of bubbles, D_e. The values of D_e are assumed to be equal to those of υ_e 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 q_G=1.67×10^-51.67×10^-4 m³/s and z₁=0.10.4 m, where q_G is the gas flow rate and z₁ is the height of water.

View full abstract

Download PDF (3112K)
Influence of the Kinds in Injection Gases on the Dephosphorization of Hot Metal

Hitoshi ONO, Tamenori MASUI, Hisashi MORI

1985 Volume 71 Issue 9 Pages 1125-1131
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1125

JOURNAL FREE ACCESS

Show abstractHide abstract

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.

View full abstract

Download PDF (1026K)
Theoretical Analysis and Model Experiments on Formation Mechanism of V-type Segregation

Hajime INOUE, Shigeo ASAI, Iwao MUCHI

1985 Volume 71 Issue 9 Pages 1132-1139
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1132

JOURNAL FREE ACCESS

Show abstractHide abstract

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.

View full abstract

Download PDF (7010K)
Strength, Low Temperature Toughness and Formability of Thermo-mechanically Treated Ti-bearing Steel Sheet

Kazutoshi KUNISHIGE, Noriaki NAGAO, Takashi MATSUOKA, Shigeki HAMAMATS ...

1985 Volume 71 Issue 9 Pages 1140-1146
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1140

JOURNAL FREE ACCESS

Show abstractHide abstract

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.

View full abstract

Download PDF (3270K)
Measurement of Cutting Temperature and Properties of Chips on the Machining of Bearing Steel in Supercooled Austenite

Yasuo FUJIOKA, Hiroshi MURO

1985 Volume 71 Issue 9 Pages 1147-1154
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1147

JOURNAL FREE ACCESS

Show abstractHide abstract

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.

View full abstract

Download PDF (5879K)
Computer Simulation of Transformation Textures in Steels

Ei-ichi FURUBAYASHI

1985 Volume 71 Issue 9 Pages 1155-1162
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1155

JOURNAL FREE ACCESS

Show abstractHide abstract

Computer simulation study has been made on the martensite texture of steels transformed from rolled austenite having the Cu-type rolled texture; the aim is to appraise variant selection rules so far proposed, i.e. "Active slip (AS) system model", "BOKROS-PARKER (BP) model", and "Twinning shear (TS) model". 360 or 720 initial orientations of austenite composing the Cu-type texture were generated using the random number, and individual orientations were transformed into martensite orientations using KURDJUMOV-SACHS, NISHIYAMA or BAIN relation in a manner of Monte Carlo method.
Pole figures of {001} structure simulated in this way were compared with experimentally determined pole figures by H. ABE et al.; the materials were Fe-25.7% Ni and Fe-30.2% Ni alloys heavily rolled in the austenitic state and transformed into martensite after rolling. The AS model and BP model were not successful in simulating the observation, but the TS model, when applied to the anti-rolling stress (i.e. stress with the sign opposite to the rolling stress), was able to explain fairly well the pole distributions of dislocated martensite texture of the Fe-25.7% Ni alloy.

View full abstract

Download PDF (1427K)
Hardness and Fatigue Behavior in Weldment of 13Cr-4Ni Steel Casting

Yoshitaka IWABUCHI, Kiyoharu AZEKOSHI, Tomoo TAKENOUCHI, Takehiro MIYA ...

1985 Volume 71 Issue 9 Pages 1163-1169
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1163

JOURNAL FREE ACCESS

Show abstractHide abstract

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.

View full abstract

Download PDF (2613K)
Detection of Defects in Welded Joint of a Structural Steel and Prediction of Fatigue and Corrosion Fatigue Lives for the Joints Containing Those Defects

Takao AOKI, Keishi NAKANO, Hiroaki FUKUHARA, Akira OKADA, Shigeo KOBAY ...

1985 Volume 71 Issue 9 Pages 1170-1177
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1170

JOURNAL FREE ACCESS

Show abstractHide abstract

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.

View full abstract

Download PDF (2754K)
Effects of Manganese and Nickel Increase on Mechanical Properties of TRIP Steel

Toshiro KOBAYASHI, Naoto WAKAI, Wataru YAGI, Toshihiko KAZINO, Yoshisa ...

1985 Volume 71 Issue 9 Pages 1178-1185
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1178

JOURNAL FREE ACCESS

Show abstractHide abstract

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.

View full abstract

Download PDF (8871K)
[title in Japanese]

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

1985 Volume 71 Issue 9 Pages 1195-1197
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1195

JOURNAL FREE ACCESS

Download PDF (647K)
[title in Japanese]

[in Japanese]

1985 Volume 71 Issue 9 Pages 1268
Published: July 01, 1985
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.71.9_1268

JOURNAL FREE ACCESS

Download PDF (2320K)

Register with J-STAGE for free!