Structural Steel and Steel Construction
Morihisa FUJIMOTO
pp. 1059-1069
Readers Who Read This Article Also Read
Tetsu-to-Hagané Vol.71(1985), No.3
Tetsu-to-Hagané Vol.71(1985), No.12
Tetsu-to-Hagané Vol.71(1985), No.4
Grid List Abstracts
ONLINE ISSN: | 1883-2954 |
PRINT ISSN: | 0021-1575 |
Publisher: | The Iron and Steel Institute of Japan |
Backnumber
Vol. 110 (2024)
Vol. 109 (2023)
Vol. 108 (2022)
Vol. 107 (2021)
Vol. 106 (2020)
Vol. 105 (2019)
Vol. 104 (2018)
Vol. 103 (2017)
Vol. 102 (2016)
Vol. 101 (2015)
Vol. 100 (2014)
Vol. 99 (2013)
Vol. 98 (2012)
Vol. 97 (2011)
Vol. 96 (2010)
Vol. 95 (2009)
Vol. 94 (2008)
Vol. 93 (2007)
Vol. 92 (2006)
Vol. 91 (2005)
Vol. 90 (2004)
Vol. 89 (2003)
Vol. 88 (2002)
Vol. 87 (2001)
Vol. 86 (2000)
Vol. 85 (1999)
Vol. 84 (1998)
Vol. 83 (1997)
Vol. 82 (1996)
Vol. 81 (1995)
Vol. 80 (1994)
Vol. 79 (1993)
Vol. 78 (1992)
Vol. 77 (1991)
Vol. 76 (1990)
Vol. 75 (1989)
Vol. 74 (1988)
Vol. 73 (1987)
Vol. 72 (1986)
Vol. 71 (1985)
Vol. 70 (1984)
Vol. 69 (1983)
Vol. 68 (1982)
Vol. 67 (1981)
Vol. 66 (1980)
Vol. 65 (1979)
Vol. 64 (1978)
Vol. 63 (1977)
Vol. 62 (1976)
Vol. 61 (1975)
Vol. 60 (1974)
Vol. 59 (1973)
Vol. 58 (1972)
Vol. 57 (1971)
Vol. 56 (1970)
Vol. 55 (1969)
Vol. 54 (1968)
Vol. 53 (1967)
Vol. 52 (1966)
Vol. 51 (1965)
Vol. 50 (1964)
Vol. 49 (1963)
Vol. 48 (1962)
Vol. 47 (1961)
Vol. 46 (1960)
Vol. 45 (1959)
Vol. 44 (1958)
Vol. 43 (1957)
Vol. 42 (1956)
Vol. 41 (1955)
08 Oct. (Last 30 Days)
Morihisa FUJIMOTO
pp. 1059-1069
Readers Who Read This Article Also Read
Tetsu-to-Hagané Vol.71(1985), No.3
Tetsu-to-Hagané Vol.71(1985), No.12
Tetsu-to-Hagané Vol.71(1985), No.4
Teruo KISHI, Akira OHTOMO, Shin YOKOI
pp. 1077-1084
Mitsuru TATE
pp. 1085-1093
Readers Who Read This Article Also Read
Tetsu-to-Hagané Vol.92(2006), No.3
ISIJ International Vol.43(2003), No.10
ISIJ International Vol.46(2006), No.4
Hiroshi G. KATAYAMA, Masanori TOKUDA
pp. 1094-1101
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.
Mutsuhiro KOBAYASHI, Heinrich W. GUDENAU, Willy G. BURCHARD, H. Christian SCHAEFER
pp. 1102-1109
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.
Kazumi MORI, Masahiro HIRASAWA, Motoshi SHINKAI, Asao HATANAKA
pp. 1110-1116
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.
Nagayasu BESSHO, Shoji TANIGUCHI, Atsushi KIKUCHI
pp. 1117-1124
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, 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.
Hitoshi ONO, Tamenori MASUI, Hisashi MORI
pp. 1125-1131
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.
Hajime INOUE, Shigeo ASAI, Iwao MUCHI
pp. 1132-1139
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.
Kazutoshi KUNISHIGE, Noriaki NAGAO, Takashi MATSUOKA, Shigeki HAMAMATSU
pp. 1140-1146
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.
Yasuo FUJIOKA, Hiroshi MURO
pp. 1147-1154
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.
Ei-ichi FURUBAYASHI
pp. 1155-1162
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.
Yoshitaka IWABUCHI, Kiyoharu AZEKOSHI, Tomoo TAKENOUCHI, Takehiro MIYAMOTO
pp. 1163-1169
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.
Takao AOKI, Keishi NAKANO, Hiroaki FUKUHARA, Akira OKADA, Shigeo KOBAYASHI, Katumi KIMURA, Michio INAGAKI
pp. 1170-1177
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.
Toshiro KOBAYASHI, Naoto WAKAI, Wataru YAGI, Toshihiko KAZINO, Yoshisada UEDA
pp. 1178-1185
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.
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
pp. 1195-1197
Readers Who Read This Article Also Read
Tetsu-to-Hagané Vol.72(1986), No.9
Tetsu-to-Hagané Vol.71(1985), No.9
Tetsu-to-Hagané Vol.72(1986), No.9
辻川 茂男
pp. 1268-1268
Readers Who Read This Article Also Read
Tetsu-to-Hagané Vol.72(1986), No.9
Tetsu-to-Hagané Vol.72(1986), No.9
Tetsu-to-Hagané Vol.71(1985), No.9
08 Oct. (Last 30 Days)
ISIJ International Vol.64(2024), No.11
ISIJ International Advance Publication
ISIJ International Vol.64(2024), No.8
ISIJ International Advance Publication
Tetsu-to-Hagané Advance Publication
Zairyo-to-Kankyo Vol.69(2020), No.11
Zairyo-to-Kankyo Vol.50(2001), No.11
Tetsu-to-Hagané Vol.69(1983), No.15
You can use this feature after you logged into the site.
Please click the button below.
Please enter the publication date
with Christian era
(4 digits).
Please enter your search criteria.