Tetsu-to-Hagane

[title in Japanese]

[in Japanese]

1976 Volume 62 Issue 7 Pages 787-788
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_787

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A Trial of Continuous Production of Iron Whiskers

Akimitsu OKURA

1976 Volume 62 Issue 7 Pages 789-797
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_789

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Iron whisker, a single crystal of high purity, has high tensile strength. This material is expected to be used as fiber in composite materials as well as electrical materials.
While whiskers have excellent properties, utilization is limited because of nonuniformity of length and of diameter.
The author have investigated the optimum condition to obtain uniformity of length and thickness of whiskers in continuous production by reduction of FeCl₂-nH₂O with hydrogen. In this study the emphasis has been placed on the description of the usefullness of a gas curtain device combined with hinged door in the processing of iron whiskers, and the discussion on the growth mechanism has been made.

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Determination of the Oxygen Content after Silicon Deoxidation by the Herty Method

Takashi SASA, Rokuro SAKAGAMI

1976 Volume 62 Issue 7 Pages 798-806
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_798

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Changes of the oxygen content in liquid iron after silicon addition have been determined by fixing the oxygen as Al₂O₃ with thin aluminum wire previously charged in the sampler and chemically analyzing the aluminum content of the inclusion which is a mixture of Al₂O₃ and SiO₂.
The results obtained arc as follows:
(1) The oxygen values at a certain time after silicon addition are independent of the amount of aluminum charged in the sampler and the kind of the sampler used.
(2) The oxygen content gradually decreases and reaches to the equilibrium value.
From these results and the calculation about the reduction of SiO₂ particles with aluminum in molten iron, it has been confirmed that besides SiO₂ particles (>1 μm), a large number of minute SiO₂ (<<1 μm) exist in liquid iron and a part of them remains to the last stage of the deoxidation process.
The result that the melt is super-saturated with oxygen untill the equilibrium is reached, is explained by the fact that the minute SiO₂ are easily reduced by aluminum during solidification of the sample.

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A Study of the Effects of CO₂ Absorption in the NaOH Solution-CO2 Gas Jet Model

Soichi INADA, Tetsuya WATANABE, Kenji ARAKI

1976 Volume 62 Issue 7 Pages 807-816
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_807

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In the gas-melt reactions which proceed by gas jet with molten metal, it is well-known that the mass transfer is greately influenced by the behaviour of gas jet imping on liquid surface, therefore, lancing con ditions are the important factor to control the reaction efficiency. There are, however, few studies which show quantatively the mass transfer from gas jet to liquid in accordance with lancing conditions.
Standing on this view point, this study has been directed for presenting an equation model which is capable of estimating the absorption efficiency of gas through the NaOH-CO₂ gas jet model. An equation model expressing the relationship between the apparent rate constant and the behaviour of gas jet has been introduced as follows: AV·k_L=dV_m²·d₀^-2 (H_O+ H_C) ^-1=α′M_j (H_O+H_C) ^-1whereA-surface area of bath, V=volume of liquid, k_L=apparent rate constant, V_m=volumetric gas flow rate, d₀=nozzle diameter, H_O=distance between the nozzle and the liquid surface, H_C=depth of crater formed by gas jet, α, α′=constant of proportionality, M_j=momentum of gas jet, respectively.
The values of the apparent rate constants K_L in the H₂O-CO₂ absorption model by BRADSHAW et al. have been reviewed according to the present equation model and the validity of the equation has been confirmed. The practical application of the present model to the VOD process for stainless steel making has been also discussed.

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Behavior of Slag Inclusions during Solidification of a Large Forging Ingot

Koreaki SUZUKI, Kozo TANIGUCHI, Tomoo TAKENOUCHI

1976 Volume 62 Issue 7 Pages 817-826
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_817

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In order to investigate the behavior of slag inclusions during solidification process of large forging ingots, granular mixtures of the synthetic slag and Fe-1%P alloy uniformly containing fine Si0₂ inclusions were held at the solid-liquid coexisting temperature. On the basis of the experimental results, some discussions were made on the behavior of exogeneous slag inclusions during solidification of a 220 t commercial ingot. The results obtained were summarized as follows; (1) Slag inclusions were found to absorb fine SiO₂ inclusions distributed in the surroundings, resulting in the decrease of CaO content during holding at the liquid-solid coexisting temperature.
(2) The change in CaO content in slag inclusions with the distance from the surface to the center of the ingot was well explained by the dilution model obtained by the experiment.
(3) The maximum diameter of inclusions growing by coagulation during solidification of the ingot was estimated to be 60-70 μm.

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Effects of Rare Earth Elements on Properties of High Quality Ingots

Moriyuki ISHIGURO, Masaharu ITO, Tatsumi OSUKA

1976 Volume 62 Issue 7 Pages 827-835
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_827

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To produce high quality high-tensile steels, rare earth metals (REM) were added into molten steel with a sulfur content 0.007% in the mould, and investigation was made on the inner quality of the 30 t big-end down ingots (amount of added REM: 0.032 and 0.052 wt%), and on the properties of the plates from these ingots. Conclusions reached are as follows:
(1) REM treatment to killed steel results in the conversion of MnS to sulphides and oxisulphides of rare earths which are hardly deformable by hot rolling. Thus, sulphide shape control can be successfully made of REM addition.
(2) REM has a stronger deoxidizing ability than Al.
(3) The separation of REM inclusions from sound ingot portions can be sufficiently made by this method as industrial process.
(4) Among inverse V-segregation in REM treated ingot, sulphur shows negative segregation. A proposal is presented to explain the cause of this negative segregation of sulphur.

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On the Natural Convection in Solidification Process

Kenichi MIYAZAWA, Iwao MUCHI

1976 Volume 62 Issue 7 Pages 836-845
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_836

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Experiments to demonstrate the behaviors of natural convection along the solidification front in the mold were conducted by the use of KCl solution as the solidification system and with the aid of the thymol blue method as the flow visualization technique.
Experimental results show that with the increase in the solidification time, the maximum velocities of natural convection in the upper region of the mold decrease monotonously and the positions at which the maximum velocity in the lower region of the mold appears approach to the solidification front. For the case of eutectic solution it is found that the mean maximum velocity in the upper region of the mold is proportional to the square root of a modified Grashof number.
Furthermore, the approximate estimations with regard to the natural convection along the dendritic interface are presented on the basis of the boundary layer theory. By comparing the observed data of the mean maximum velocities with those calculated curves, the effects of the fluid flow in mushy zone on the velocity in the boundary layer and on its thickness are investigated.

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Effect of the High-Temperature-Coiling on the Properties of Continuously Annealed Product

Haruo KUBOTERA, Kazuhide NAKAOKA, Kenji ARAKI, Kaoru WATANABE, Koji IW ...

1976 Volume 62 Issue 7 Pages 846-855
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_846

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In contrast to the established processing principle for the batch annealed cold rolled sheet gauge product, where the hot strip is coiled at a temperature around 560°C, coiling at a higher temperature near 700°C is desirable when the cold rolled strip is processed through the continuous annealing line.
The high temperature coiling is beneficial both to the formation of faborable recrystallization texture and the grain growth at the continuous annealing stage. These beneficial effects owe to the microstructure of the hot band, which is characterized by the coarsened carbides and a larger ferrite grain size. Of these, the former is responsible for both the texture formation and the larger ferrite grains.
The coagulated carbides serve to make the situation where recrystallization commences with the solute carbon content far less than the solution limit, leading to the formation of the {111} rich texture.
The coagulation of carbides is beneficial also to the grain growth, since the spacing of the particles are several times larger than the recrystallized ferrite grain diameter and the inhibition of grain boundary migration is greatly reduced.

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Effects of Strain, Strain Rate, and Temperature on the Hot Worked Structure of a 0.16% Carbon Steel

Seita SAKUI, Taku SAKAI, Kazuo TAKEISHI

1976 Volume 62 Issue 7 Pages 856-865
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_856

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The high temperature tensile deformation of a 0.16% carbon steel was studied over a wide range of strain rate from 18 sec^-1 to 2.6×10^-4 sec^-1 in the austenite range. From the metallographic investigation of the specimens quenched by hydrogen gas instantaneously after deformation, it was observed that the structure rapidly deformed (ε=18 sec^-1), which was very unstable at deformation temperature and underwent static recrystallization in less than 0.2 seconds, was retained to room temperature by the instantaneous quenching.
The relation between the strain at which the structure changes distinctly (ε_c), and the strain at the firstmaximum flow stress (ε_M) is expressed by the following equation; ε_c= (0.72±0.06) ·ε_M. The average grain size varied with the increasing strain in the range over ε_c and approached to a value determined by the strain rate (and the temperature) in high strain region. The final grain size (D) is dependent solely on the first maximum flow stress (σ_M) regardless of the deformation conditions (i. e. initial structure, temperature and strain rate), and expressed by σ_M=σ₀+K·D^-N, where σ₀, K and N are constants, and 17σ0 and N are equal to zero and 0.70, respectively. The deformed structure in high strain region showed a mixture of uniformly distributed isolated fine grains and comparatively coarse grains with serrated boundaries whose period was about the smaller grain size, and this state of mixture was almost the same regardless of the deformation conditions.
The apparent activation energy for high temperature deformation obtained from the temperature and the strain rate dependence of σ_M was approximately equal to that for the self-diffusion of Fe atom in the austenite range of 0.16% C-Fe. It is concluded, therefore, that the deformation of 0.16% C-Fe in the austenite range is controlled by the dynamic recrystallization process in terms of the self-diffusion of the Fe atom. This fact suggests that whether the observed stress-strain curve shows a peak stress type or a stress oscillation type depends on the difference between an initial grain size (D₀) and a dynamically recrystallized grain size (D), and the peak stress type curve is observed when a grain size decreases with deformation (D<D₀), and the stress oscillation type curve appears when a grain size increases with deformation (D>D_O).

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Effect of Shape of MnS Inclusion on Ductility of Rolled Plate

Hisashi TAKADA, Koji KANEKO, Tsuyoshi INOUE, Shushi KINOSHITA

1976 Volume 62 Issue 7 Pages 866-874
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_866

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A study has been made of the effect of shape of MnS inclusion on the directionality of mechanical properties using a commercial grade 0.13%C-1.34%Mn steel. Shapes of inclusion are varied with temperature and reduction ratio of rolling. Mechanical properties of longitudinal (L), transverse (C) and through-hickness (Z) directions are measured.
MnS inclusion deforms to greater extent as rolling temperature decreases and relative plasticity of inclusion (ratio of plasticity of inclusion to that of matrix) is about 0.5 at 1250°Cand 1.0 at 900°C. The variation of ductility (reduction of area and Charpy shelf energy) with rolling conditions is clearly described as a function of IAR (inclusion aspect ratio) in each direction.
Efforts are made on expressing the ductility in one parameter regardless of direction and rolling conditions and it is found that Charpy shelf energy can be described as a function of log (1-2f_A/2f_A), where 2f_A is the area fraction of MnS inclusions on the ductile fracture surface of a test piece.

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Observations of Ductile Fracture Processes and Criteria of Void Initiation in Spheroidized and Ferrite/Pearlite Steels

Tsuyoshi INOUE, Shushi KINOSHITA

1976 Volume 62 Issue 7 Pages 875-884
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_875

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An investigation was made of the ductile fracture processes both in spheroidized and ferrite/pearlite steels.
Transmission electron microscopic study was performed to observe the dislocation structures in and around spheroidite and pearlite at the stage prior to void initiation. Stages of growth and linkage of voids were pursued by means of scanning electron microscopy.
In the vicinity of spheroidite and pearlite, dislocation tangling and cell formation occur as deformation proceeds. A few dislocations were observed in cementite both in spheroidite and pearlite at strains immediately before void initiation.
Combining these observations with previously reported results, criteria of void initiation were discussed. In spheroidized steels, stress predicted by Fisher-Hart-Pry (FHP) model is exerted on spheroidite and void initiation occurs when the stress reaches the fracture stress of cementite. In ferrite/pearlite steels, FHP stress applied to pearlite induces slips in pearlitic ferrite and secondary stress concentration to cementite plate. This secondary stress can be predicted by Ansell-Lenel model and void initiation occurs when the secondary stress overcomes the fracture stress of cementite.

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Resulphurized Steels Containing Zirconium

Kiichi NARITA, Yoshihiro YAMAGUCHI, Naoomi YAGI, Takashi SHIMOHATA

1976 Volume 62 Issue 7 Pages 885-894
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_885

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Effects of zirconium addition on sulphide morphology, mechanical properties and machinability of resulphurized steels have been studied. Zirconium forms zirconium oxide, nitride, carbon-nitrogen sul phide and different types of sulphides in resulphurized steels. Remarkable improvements of sulphide morphology are observed in hot rolled steels containing a certain minimum amount of zirconium or more, which depends on both nitrogen and oxygen contents in steels. X-ray diffraction and electron diffraction analyses show that this non-deformable sulphide during hot rolling is MnS-Zr₃S₄ eutectic.
The formation of oval sulphide by zirconium addition has beneficial effects on the tensile ductility for the transverse specimens and the cold forgiability evaluated by the upset test, while little effect is observed for the properties of the longitudinal specimens.
Effects of zirconium addition on the machinability have also been investigated. In turning with high speed steel tool, the tool life, cutting force and cutting ratio are not apparently influenced by zirconium addition. Oval sulphides in zirconium contained steels, however, promote the void formation at the sulphide/matrix interface in the primary shear zone during chip formation.

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Effect of Boron on Transformation of Low-Carbon Low-Alloy Steels

Kazuo YAMANAKA, Yasuya OHMORI

1976 Volume 62 Issue 7 Pages 895-904
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_895

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The effect of boron on the transformation of low-arbon-1/2 Mo steels has been investigated by means of dilatometry and microstructural observations.
The steels containing below 30 ppm of boron exhibit the largest hardenability in case of austenitization at 930°C, but the hardenability is reduced by austenitization at higher temperatures. The hardenability of the steel containing boron of 60 ppm does not vary with the austenitizing temperature.
The steel with higher boron content of about 95 ppm increases its hardenability with increasing the austenitizing temperature up to 1 130°C.
Such behaviour can be explained in terms of grain boundary segregation of boron and the precipitation of Fe₂₃ (B, C) ₆. In addition to this, the effects of the precipitation of BN on hardenability and the crystallography of Fe₂₃ (B, C) ₆ are discussed.

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Review of the Recent Development of Electrical Sheet Steel

Satoru TAGUCHI

1976 Volume 62 Issue 7 Pages 905-915
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_905

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Metamorphism of Snow Crystals and Ice Sintering

Daisuke KUROIWA

1976 Volume 62 Issue 7 Pages 916-925
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_916

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Report of the Steel Plates and Sheets Committee of the Joint Research Society of ISIJ

Yasuo ARIMURA

1976 Volume 62 Issue 7 Pages 926
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_926

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Report of the Blooming and Slabbing Subcommittee of Steel Plates and Sheets Committee

Shigeru TAMAMOTO

1976 Volume 62 Issue 7 Pages 926a-931
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_926a

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Report of the Plates Subcommittee of Steel Plates and Sheets Committee Ryoji KUROTSU

Ryoji KUROTSU

1976 Volume 62 Issue 7 Pages 931-935
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_931

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Report of the Hot Strips Subcommittee of Steel Plates and Sheets Committee

Syuko MATSUMOTO

1976 Volume 62 Issue 7 Pages 935-936
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_935

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Report of the Cold Strips Subcommittee of Steel Plates and Sheets Committee

Hisashi TAKAHASHI

1976 Volume 62 Issue 7 Pages 937-940
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_937

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[title in Japanese]

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

1976 Volume 62 Issue 7 Pages 941-948
Published: June 01, 1976
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.62.7_941

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