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Nobuo TSUCHIYA, Seiji TAGUCHI
1983 Volume 69 Issue 16 Pages
1945-1954
Published: December 01, 1983
Released on J-STAGE: February 15, 2010
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In Response to a Question in a Column : "How can we measure the atomic size of solute?"
Kiyoyuki TERAKURA
1983 Volume 69 Issue 16 Pages
1955-1960
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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Mitsuo YAMASHITA, Mitsuru WAKAMATSU
1983 Volume 69 Issue 16 Pages
1961-1966
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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Hiroshi MATSUZAWA
1983 Volume 69 Issue 16 Pages
1967-1971
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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-Report of the Joint Research Society, ISIJ-JISTIC-
Yukio YAMADA
1983 Volume 69 Issue 16 Pages
1972-1973
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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Tsuneo MIYASHITA, Hideyuki YOSHIKOSHI, Seiji MATSUI, Osamu TAJIMA, Hir ...
1983 Volume 69 Issue 16 Pages
1974-1981
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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For the purpose of developing a process in which the cold pellet can be produced in about 10 hours, the continuous rapid curing procedure has been investigated using iron ore pellet with 10%-portland cement and dust pellet with 14%-B.F. granulated slag as binder.
1) A continuous curing with about 10 hours is possible by the combination of pre-drying, steaming below 100°C and drying.
2) The strength of pellet using portland cement is improved in drying with atmosphere.
3) In the operation of pilot plant with 6.5 ton/day, the compressive strength of produced ore pellet and dust pellet are 170-200kg p and 140-170kg/ p respectively, and their physical properties are comparable to that of fired pellet.
4) The required energy of this process is about 80 000kcal t product, and this process is a polution-free and energy saving process in which the waste gas from the plant can be used.
5) The hydrates of cement are decomposed in 800-900°C, however, the shape and strength of pellet are remained by sintering between ore and cement particles. Above 1 000°C the coherence of pellet is reinforced. This phenomena agree with the behavior of swelling and strength of pellet during reduction.
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Takaji KUSAKAWA, Manabu OHORI, Tomoyuki OBANA, Chihiro TAKI, Kiichi HA ...
1983 Volume 69 Issue 16 Pages
1982-1988
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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This work was carried out to obtain the knowledge of the dephosphorization ability of calciumsiliside. Electrolytic iron was melted in magnesia crusibles in a flow of argon gas. After melted down, the mixture of calciumsilicide and calciumfluoride was added on the surface of the molten iron as flux. The results obtained are summarized as follows.
1) In the case of the single addition of calciumsilicide, the phosphorus concentration decreased only a little. In the case of the mixture of calciumsilicide and calciumfluoride, however, the decreasing of the phosphorus concentration was markedly observed.
2) The degree of dephosphorization increased, as the amount of calciumsilicide in the flux increased.
3) The rate of dephosphorization increased, as the amount of calciumfluoride in the flux increased.
4) As the initial carbon concentration increased, the degree of dephosphorization decreased.
5) Spheroidal calciumphosphides were observed in the flux on the inside surface of the magnesia crusible.
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Kazumi OGINO, Kiyoshi NOGI, Chiaki HOSOI
1983 Volume 69 Issue 16 Pages
1989-1994
Published: December 01, 1983
Released on J-STAGE: February 16, 2010
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The effect of coexistence of a plural surface active elements, oxygen and sulphur, on the surface tension of molten iron has been studied. Measurements of the surface tension of molten iron have been carried out with the sessile drop method at 1 600°C.
The surface tension of molten Fe-O-S alloy is represented by the following equation.
γ=1 910-825 log(1+210wt%O)-540 log(1+185wt%S) (dye/cm) (0≤wt%O/0.0160+wt%S/0.0300≤1)
The validity of the equation has been confirmed by an application of this equation to data of other investigators.
The average occupied area in the coexistence of oxygen and sulphur is smaller than that in the individual existence of oxygen or sulphur in molten iron. This fact implies that oxygen and sulphur are more closely packed when they coexist.
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Hidemaro TAKEUCHI, Shogo MATSUMURA, Yasunobu IKEHARA
1983 Volume 69 Issue 16 Pages
1995-2001
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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Surface segregation is often found to occur on oscillation marks of continuously cast austenitic stainless steel slab surface. The actual state of surface segregation and the effect of oscillation conditions on them have been investigated in order to make clear the formation mechanism of surface segregation.
1) Surface segregation occurs only in the valley of osillation marks and two typical forms, over-flow type and mini-bleed type, are observed.
2) Surface segregation is composed of bands of enriched solutes, (Ni), (Mn), (Si), (P), etc.
3) The shorter the negative strip time (
tN) is, the smaller the freqency of occurence and depth of surface segregation become.
4) It is considered that the formation mechanism of surface segregation can be explained by over-flow and bleeding-out of solute enriched molten steel into oscillation marks of slab surface.
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Masashi MITSUTSUKA, Heiji MORISE, Tetsuya OGURA, Osamu NAKAMURA
1983 Volume 69 Issue 16 Pages
2002-2009
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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In order to save the cooling time of billets on cooling bed, a fog-jet cooling process has been investigated. The main results obtained are as follows :
(1) To realize homogeneous and regulating cooling of billets, the most favorable cooling process consists of on-corner arrangement of billets and air-atomized fog-jet cooling
(2) From the standpoints of depressing the cracking and deforming of billets by forced-cooling and to save required time for cooling, the following two step cooling process is suitable: the natural cooling for high temperature zone (the initial to about 500°C) and the fog-jet cooling for low temperature zone (under about 500°C).
(3) In the cases of 123mm square billets containing from 0.2 to 0.8wt% carbon they are naturally cooled from about 1 000°C down to about 550°C (billet core temperature), and then fog-cooled under impinged water flux equal or lower than 20 and 40
l/m
2·min at top and bottom, respectively, and are scarecely unfavorably affected in their structures and mechanical properties.
In addition, the following items have been studied: influence of billets arrangement on cooling time, fog-cooling conditions of decreasing bending of billets, influence of carbon content on cooling curves during natural cooling, influence of scale on billet surfaces on cooling curves during fog-cooling, deflection of asrolled hot billets, selection of fog nozzle free from clogging, and an example of basic design of a billet cooling bed with fog-cooling facilities.
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Osamu NAKAMURA, Mikihiko TAURA, Masashi MITSUTSUKA, Heiji MORISE, Kenj ...
1983 Volume 69 Issue 16 Pages
2010-2015
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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New fog cooling facilities for billets have been developed at Kamaishi Works, Nippon Steel Corporation. The facilities have a walking beam type cooling bed, and as-rolled hot billets are arranged on their corners and rotated on the bed in walking.
The billets are natural-cooled from the initial temperature to about 550°C (core temperature) at the front part of bed and then fog-jet-cooled to about 100 °C at the later part.
In this report the following items are described: the new techniques developed, the basic design and main specifications of the facilities, the passages of constructions and operational performances, improved points and unsettled problems, and others.
Main techniques developed are the billet straightening mechanism using billet pusher, the system of oncorner arrangement and rotation of billets on the cooling bed, and the fog jet cooling device of billets having the crossflow type nozzles.
This instalation has been smoothly operated since June 1975 with a sufficient cooling capacity using the fogcooling method for all billets containing carbon lower than 0.75 wt%. This has given no cracking and less deformation, very small reject level of billets (about 0.05%), and no nozzle clogging for about eight years.
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Junji KIHARA, Ken ISHIGURO
1983 Volume 69 Issue 16 Pages
2016-2023
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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The widthspread behavior in flat rolling is an old but still important problem to be clarified, because it is one of basical problems in general caliber rolling, and is more important for caliberless rolling technique.
Several geometrical parameters have been investigated about how they affect the widthspread behavior in actual hot rolling experiments. They are rolling reduction, ratio of thickness to roll radius and ratio of width to thickness. From an energetical point of view, a simple calculation system of the mean widthspread is proposed and evaluated by using the experimental results, which strongly support the calculating system; in the range of 0.64-3.6 of width/thickness, and 0.18 to 0.50 of thickness/roll radius. The side barreling behavior is expressed with 4-th power polynominal very well in wide range rolling conditions, and the mathematical expression with rolling parameters mentioned above are obtained in the same range as for the mean widthspread behavior. For the range of high value of thickness/roll radius, greater than 0.86, however, succesful expression is not obtained, although in this range the side barreling behavior can be still well expressed with 4-th power polynominal function of the coordinate in thickness direction.
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Junji KIHARA
1983 Volume 69 Issue 16 Pages
2024-2029
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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A passive mill which was made originally for testing lubricants in aluminum cold rolling is reformed to a more powerful one suitable to the tester of lubricants in cold rolling of steel strips. In the tester, tribological conditions, i.e., rolling load, circumferential velocity of roll, exit strip velocity and so on can be varied independently. With use of the tester, are tested five sorts of lubricants modelling the actual lubricants in practice. After the cource of experiments, it is found that almost all lubrication properties in practice are able to be reproduced in the tester, and the classification of grade of each lubricant is easy with use of the tester.
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Seiichi MUNEKI, Yoshikuni KAWABE, Junji TAKAHASHI
1983 Volume 69 Issue 16 Pages
2030-2036
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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It has been reported that the maximum tensile strength of maraging steel attainable by applying thermomechanical treatment consisting of hot rolling+aging was about 360 kgf/mm
2. The purpose of this study was to increase further this tensile strength by changing the alloy composition based on 10Ni-18Co-12Mo-1Ti maraging steel and by applying the thermomechanical treatment consisting of the hot rolling+cold rolling+aging. Cold rolling was effective for increasing the strength of 10Ni-18Co-12Mo-1Ti maraging steel by improving toughness and preventing the unstable fracture in low stress levels. However, strengthening and toughening by cold rolling were strongly dependent upon the hot rolling conditions, because the microstructures were greatly changed. This increase in strength was most pronounced for the specimen having the microstructure with the fine grain and the reduced amount of coarse precipitates formed in the austenite. The tensile strength of 397 kgf/mm
2 was achieved in the 10Ni-18Co-12Mo-2Ti, 10Ni-20Co-12Mo-1Ti, and 10Ni-18Co-14Mo-1Ti maraging steels which were properly hot rolled and then cold rolled for 80% reduction. When the cold reduction exceeded 80%, the specimen became susceptible to unstable fracture in a low stress level and the tensile strength exhibited a wide scatter, but the highest tensile strength of 438 kgf/mm
2 was achieved by some of 95% cold rolled specimens in this study.
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Kentaro ASAKURA, Toshio FUJITA, Hidenori MIYAKE
1983 Volume 69 Issue 16 Pages
2037-2044
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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The effect of carbon on creep rupture properties and room-temperature toughness of (910)Cr-(1.82)Mo heat resisting steels with V and Nb was studied. The amount of carbon content was varied from 0.02% to 0.23% in order to improve toughness without decrease in creep rupture strength. The difference in creep rupture strength and Charpy absorbed energy between 10Cr-2Mo steels and 9Cr-1.8Mo steels was studied with respect to the ratio of δ-ferrite to martensite, the precipitates, and the microstructure.
The results indicated that the 9Cr-1.8Mo-0.1V-0.05Nb steels with 0.05-0.14%C tempered at 800°C showed good toughness, and that 10
4h rupture strength of the steel was as high as that of SUS 316 at 550°Cand SUS 304 austenitic stainless steel at 600°C. It was concluded that the optimum amount of δ-ferrite with respect to both creep rupture strength and Charpy absorbed energy was 1020%.
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Tatsuhiko TANABE, Tatsuo SHIKAMA, Yoshikazu SAKAI, Masakazu FUJITSUKA, ...
1983 Volume 69 Issue 16 Pages
2045-2051
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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Creep rupture properties of Ni-Cr-W alloys developed for nuclear steel making, which precipitate α-W, were investigated in the temperature range from 900°C to 1 050°C in He environment (He-2) which simulates the primary coolant of High Temperature Gas Cooled Reactor (HTGR), and at 900°C in reducing gas environment which is to be used when direct steelmaking system is connected with the primary system of the HTGR. The results were discussed in terms of environmental factors such as carburization, decarburization and oxidation. It was found that the two alloys have the possibility to satisfy the target of R & D, that is, "the alloy should have the 50 000 h rupture strength of more than 1 kg/mm
2". Further, the degradation of the rupture strength in the alloy which has α-W as a main strengthener, did not appear in spite of severe decarburization of the alloys.
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Tatsuhiko TANABE, Tatsuo SHIKAMA, Yoshikazu SAKAI, Masakazu FUJITSUKA, ...
1983 Volume 69 Issue 16 Pages
2052-2059
Published: December 01, 1983
Released on J-STAGE: February 15, 2010
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Creep rupture properties of heat resistant alloys with carbide or carbide and γ' precipitates were investigated in the temperature range from 900° to 1 050°C in He and reducing gas atmospheres. The degradation of the rupture strengths took place in the alloys, which have carbide as a strengthener, due to decarburization in He atmoshere at higher temperature than 1 000°C. In the alloy which was strengthened mainly by γ', the solutioning of γ' led to the degradation of the rupture strengths, but to the restoration of rupture ductilities in greater extent. A new method to predict the rupture life, steady state creep rate, etc. from 0.2% proof stress was proposed. In most cases, the method was found to be satisfactory in the sense that it represents the degradation behaviour of the alloys according to various causes.
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Keiichi SHIMOMURA, Tetsuo SHOJI, Hideaki TAKAHASHI
1983 Volume 69 Issue 16 Pages
2060-2067
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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The feasibility of using acoustic-emission techniques for elastic-plastic fracture toughness test of a Cr-Mo-V steel at a high temperature has been examined. Fractographic study and frequency analysis characterization of AE behavior have been carried out. AE signals observed during the test can be classified into three groups: Type I, II, III, and three different types of fracture surfaces are observed. Some interruption tests reveal that Type I AE is generated from the micro-cracking due to decohesion of MnS inclusions or coalescence between main crack and voids nucleated by decohesion of MnS inclusions, Type II AE having the largest amplitude from the intergranular pop-in cracking, and Type III AE from the formation of intergranular dimple facet, respectively.
JiAE denoted by an abrupt increase of ∑
EAE-
J correlation is proposed as a conservative fracture toughness characterizing the intergranular cleavage cracking.
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[in Japanese]
1983 Volume 69 Issue 16 Pages
2067
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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Hiroyuki TSUGE, Junichiro MURAYAMA, Hiroo NAGANO
1983 Volume 69 Issue 16 Pages
2068-2075
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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Effect of oxyanions such as MoO
2-4, WO
2-4, and CrO
2-4 on the intergranular stress corrosion cracking (IGSCC) of Type 304 stainless steel in high temperature water was studied. The results obtained are as follows :
1) Addition of such oxyanion as MoO
2-4, WO
2-4, and CrO
2-4 suppresses IGSCC of sensitized Type 304 stainless steel in high temperature nondeaerated water. The effectiveness of the inhibitive action by the oxyanion is ranked in the order of MoO
2-4>WO
2-4>CrO
2-4.
2) The mechanism of IGSCC inhibition by MoO
2-4 ion for sentized Type 304 stainless steel in high temperature water is considered as follows, i.e., the presence MoO
2-4 ion decreases the dissolution rate of Cr depleted zone at grain boundaries to the level of matrix by helping the formation of the Cr rich film containing MoO
3 or adsorbed MoO
2-4 ion on the surface of Type 304 stainless steel.
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Koji SHIBATA, Natsuki NAMURA, Yasuo KISHIMOTO, Toshio FUJITA
1983 Volume 69 Issue 16 Pages
2076-2083
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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Low cyclic fatigue behavior of some 18Cr-8Ni and 25Cr-20Ni austenitic stainless steels has been studied. Cyclic softening was observed after the initial cyclic hardening in all the steels investigated. The formation of α' martensite during the cyclic deformation depressed the softening and introduced the second hardening. The softening was revealed remarkably by nitrogen addition, and solute carbon also produced large softening but to a lesser degree than nitrogen. The cyclic softening occured especially in the surface layer of the specimens, and more slip bands were observed at the surface of the specimens showing the remarkable softening. A planar structure of dislocations was produced and a cell structure was scarcely observed in all the steels showing the large softening, while dislocations tended to form a cell or a band structure in the steels showing the small softening. The planar structure might enhance the cyclic softening through increasing the Bauschinger effect, the density of mobile dislocation, and/or the number of the slip band. The tendency of dislocations to form the planar structure could not be explained only with the stacking fault energy. The large cyclic softening observed in this study seemed to increase the fatigue life. In the case of stress controlled tests, however, the lives of the steel showing the significant softening were shorter, when they were compared at about the same strength ratio of the applied stress to 0.2% proof stress or ultimate tensile strength.
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Tadashi CHIDA
1983 Volume 69 Issue 16 Pages
2084-2086
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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Tomomi MURATA, Minoru SASAKI, Isamu TAGUCHI
1983 Volume 69 Issue 16 Pages
2087-2092
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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[in Japanese]
1983 Volume 69 Issue 16 Pages
2093-2094
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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[in Japanese], [in Japanese]
1983 Volume 69 Issue 16 Pages
2098
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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[in Japanese], [in Japanese], [in Japanese]
1983 Volume 69 Issue 16 Pages
2099-2100
Published: December 01, 1983
Released on J-STAGE: June 30, 2009
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