Tetsu-to-Hagane

[title in Japanese]

[in Japanese]

1969 Volume 55 Issue 10 Pages 865-866
Published: September 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.10_865

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Theoretical Analyses on the High Pressure Operation and Oxygen Enriched Operation of Blast Furnace

Keichi WAKABAYASHI, Masami FUJIURA, Takashi MORI, Nobuo INOUE

1969 Volume 55 Issue 10 Pages 867-876
Published: September 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.10_867

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Mathematical models are proposed for analizing blast furnace preformance.
High pressure operation and oxygen enriched operation are studied with the proposed models. The production rate and the fuel ratio predicted from the models agreed very well with the operation data. Also, possibility of predicting production limit is discussed.

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Kinetics of Nitrogen Removal from Liquid Iron

Kanae SUZUKI, Kazumi MORI, Yohei ITO

1969 Volume 55 Issue 10 Pages 877-886
Published: September 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.10_877

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The rate of nitrogen removal from liquid iron containing oxygen has beenstudied by blowing Argas onto the inductively stirred liquid iron at I600°C.
At constant oxygen content, the rate of nitrogen removal is proportional tothe second power of the concentration of nitrogen in liquid iron. The rate is retarded markedly with increasing oxygen content. The rate constant κ(cm/wt%. sec) is inversely proportional to the concentration of oxygen contents ([%O]>0.01%), but at lower contents of oxygen the rate constant tends to approach a con-stant value.
It is shown that the removal of nitrogen is controlled by the chemical reaction rate. The results are

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On the Behavior of the Oxide Inclusions of System MnO-Si0₂-Al₂O₃ in Steels during Hot-rolling, and their Influence on Tensile Strength of the Steels

Hikoya IWAI, Bunzo TSUJINO, Shigeteru ISA, Takeo Ao

1969 Volume 55 Issue 10 Pages 887-900
Published: September 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.10_887

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The oxide inclusions in commercial steels consist mainly of the simple orthe complex oxides formed from the system MnO-SiO₂-Al₂O₃.
In the present investigations, the behavior of those oxide inclusions in steels during hot-rolling was observed by the same procedures as used for our previous work: that is, the steel specimens containing uniformly a certain amount of those oxide inclusions were prepared by powder metallurgy technique. These steel specimens were hot-rolled under the following conditions: the rolling temperatures were 1250-1000°C and 1000-800°C, the rolling ratio was 1/5. Then, changes of inclusions in shape, composition and crystallographic structure during hot-rolling were examined. The tensile tests of rolled steel specimens in the rolling direction were carried out to examine the influence of those inclusions on tensile strength of the steels.
The main results were as follows:
(I) The complex inclusions having nearly the same melting or softening points as the rolling temperature, were deformed plastically and turned into the stringer type. When both the rolling temperature and ratio are maintained to constant, the lower the melting point of inclusion and the better the homogeneity in composition of inclusion are, the larger the degree of deformation of inclusion becomes.
(2) The complex inclusions formed from the system MnO-SiO₂, having low melting points were softened at 1000°C.
(3) When the steel specimens coexisting MnO and SiO₂ of simple oxide inclusions were rolled between 1250°C and 1000°C, both inclusions were consolidated, tusned into manganese silicates whose melting points were lower, and deformed plastically. Those manganese silicates were partly crystallized into tephroite (2MnO.SiO₂).
(4) Those oxide inclusions in steels affected scarecely tensile strength of steels.

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Study on Development of High Mn Austenitic Heat Resisting Steel

Choice of base composition and the effect of small additions of Ti and Nb

Tohru MIMINO, Kazuhisa KINOSHITA, Isao MINEGISHI, Takayuki SHINODA

1969 Volume 55 Issue 10 Pages 901-915
Published: September 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.10_901

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High Mn austenitic stainless steel has been developed for high temperature applications especially for boiler tubes. The most suitable chemical composition has been found to be 18%Cr-6%Ni-8%Mn, the structure this steel is almost wholly austenitic and its properties of creep-rupture strength, resistance to oxidation at elevated temperature and hot workability are comparable to those of type 304 steel.
Small amounts of Ti and Nb have been added simultaneously to this type of steel (being called 18-6-8Ti Nb steel) to improve the elevated temperature strength. The carbon content being about 0.2%, the optimum amounts of Ti and Nb have been found to be the atomic ratio of (Ti+Nb)/C being in the range of 0.1 to 0.5. The resultant steel has considerably high creep-rupture strength in the temperature 600 to 700°C, and is believed to be very economical steel for high temperature applications.
The mechanism of raising the creep-rupture strength due to the additions of Ti and Nb is considered to be to depress the coalescence of M₂₃C₆ carbides in the grains and on the grain boundaries and to make the carbides dispersing very finely within the grains during its use at high temperature. This mechanism is seemed to be the same as in the case of 18%Cr-10%Ni austenitic steel.

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On the Evaluation of Steel Quality by Non-destructive Testing Technique

Eiji ISONO

1969 Volume 55 Issue 10 Pages 916-931
Published: September 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.10_916

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The 2nd Report of Comparative High Temperature Tensile Testing of Steels

Shuji TAIRA

1969 Volume 55 Issue 10 Pages 932-945
Published: September 01, 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.10_932

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[title in Japanese]

1969 Volume 55 Issue 10 Pages 946-955
Published: September 01, 1969
Released on J-STAGE: December 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.10_946

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Erratum to : Electric Conductivity of Liquid PbO-SiO₂, PbO-GeO₂, PbO-P₂O₅, PbO-B₂O₃ PbO-SiO₂-GeO₂Systems

1969 Volume 55 Issue 10 Pages N178
Published: 1969
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.55.10_N178

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