Tetsu-to-Hagane

[title in Japanese]

[in Japanese]

1961 Volume 47 Issue 14 Pages 1871-1872
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1871

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Activity of CaO in the Binary System CaO-SiO₂

Activity of lime in blast-furnace type slags-I

Kiyoshi SAWAMURA

1961 Volume 47 Issue 14 Pages 1873-1878
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1873

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The e. m. f. measurement of double cells was applied in order to determine directly the activity of CaO in CaO-SiO₂ slags at 1, 600°C.
The electrodes used in the cell were of two tungsten rods, which had been treated in a molten slag bath by passage of direct current as cathodes and confirmed to be capable of using for a calcium electrode by electrode potential measurement, spectroanalysis and X-ray diffraction.
The e. m. f. of eight CaO-SiO₂ slags against a reference slag and the e. m. f. of one of them against the CaO-Al₂O₃ molten slag coexisting with solid lime were measured at 1, 600°C. From these observed values the activities of CaO at 1, 600°C relative to solid lime were calculated.
The activity of SiO₂ in the system was also found from that of CaO relative to solid silica by means of the Gibbs-Duhem relation.
Even a small amount of the sulfur in slags lowered very rapidly the activity of CaO in them.

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On the Microscopic Structure and Chemical or Crystalline Composition of Nonmetallic Inclusions in Steel

Tomizo ONUKI, Yosaku KOIKE, Tomio CHIBA

1961 Volume 47 Issue 14 Pages 1878-1883
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1878

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The remarkably large streak seams occurred under particular operational conditions or experiments were observed to study precisely the mutual relations among their microscopic structures, chemical compositions, crystalline structures with an X-ray diffraction and polarizing microscope and by measurement of microhardness and etching grade. Most of these inclusions were artificially composed in order to identify the compositions of inclusions and to research the process of such occurrence.
(i) The physical and chemical characters of α-alumina, SiO₂, MnO, MnO-FeO, sulphide, comparatively simple silicate and aluminate were sufficiently ascertained.
(ii) Microhardness test on inclusions was easily carried out in general case and recognized to be effective for the determination of various inclusions.
(iii) Grades of etching caused by reagents on each crystalline compositions of inclusions were different respectively, but often difficult to be decided quantitatively.(iv) According to these experiments, chemical or crystalline compositions of streak seams can be nearly detected by their microscopic structure and microhardness.
(v)α-alumina inclusions were sometimes produced from the mullite in chamotte, when the deoxidation product which contained a high percentage of MnO reacted with the refractory chamotte.

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Temperability of Mn-Cr Spring Steel

Manabu UENO, Iku UCHIYAMA, Akihiko HOSHINO

1961 Volume 47 Issue 14 Pages 1884-1892
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1884

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The temperability of the Mn-Cr spring steel, namely the behaviors of the carbide and the mechanical properties going through a process of tempering are studied in this report, and the results obtained are as follows:
(1) In the case when the tempering parameter T (C+log t) is introduced, the hardness is decreased linearly with tempering parameter up to 500°C.
(2) From measurement of X-ray line broadening, it is suggested that the hardness is dependent upon the lattice strain of ferrite.
(3) By the tempering above 500°C, the alloy elements such as Cr and Mn concentrate into the carbide phase; and there is a remarkable fall in the hardness that is caused by the removal of the alloy elements from the matrix ferrite. So, it is possible to conclude that the factors affecting on the hardness are the crystal strain of a matrix ferrite and- also the content of alloy elements in the ferrite.
(4) The shapes of the carbide formed during tempering does not affect the hardness, but the ductility and the fatigue strength.
(5) The yield-tensile ratio takes a low value in the presence of an excessive lattice strain of ferrite; and, with rising of the tempering temperature, this value is increased gradually as a result of disappearance of strain.
However, it tends to be decreased by growth of carbide particles with further rising of tempering temperature. Consequently, it takes the maximum value at a temperature of 450-500°C.

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Hot-Twist Ductility of High Cr-Ni Austenitic Steels

Study on high Cr-Ni austenitic steels-I

Fujio TSUKAMOTO, Takashi SUZUKI

1961 Volume 47 Issue 14 Pages 1892-1898
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1892

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The “hot-twist ductility” of highly alloyed austenitic steels such as AISI type 309, 310 and 330 was studied. Effects of alloying elements, melting practices, and grain size of these steels on the “hot-twist value” at testing temperatures ranging from 1, 000 to 1, 300°C were mainly investigated by torsion testing at a rate of 200 rpm.
Fully austenitic specimens showed twist value curves of a convex type at testing temperatures, while two-phase specimens had much lower twist values than the former, nearly constant through all testing temperatures. With the former specimens, a transcrystalline fracture was observed at temperatures lower than that showing maximum twist value, while an intercrystalline fracture was shown at temperatures higher than that.
In the case of type 310 steel, the higher the carbon content of specimen, the lower was its twist value. On the other hand, the maximum twist value was obtained with 0.2% C specimen in the case of type 309 steel. This difference was attributed to the fact that the ductility of these steels depended upon the stability of austenitic structure.
Besides, effects of Si, Ni, Cr, N and Nb contents on twist value were explained. Comparing vacuum-melted with air-melted specimens, the effect of melting atmosphere was not so clear than that of alloying elements. Addition of small quantity of Al improved hot-twist ductility, while addition of large amount of Al as well as B up to 0.01% in the form of Fe-B much impaired ductility.
In the case of high-C steels, the increase of annealing temperature which resulted in grain-coarsening decreased the hot-twist value owing to the increase of solubility of C atoms, while no change of the hot-twist value were observed with very low-C steels. Therefore, it was concluded that grain size itself did not affect the hot ductility.

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Effect of Mo, Si and Cu Additions, Respectively, on Mechanical Properties and Corrosion Resistance of 30Ni-20Cr Stainless Steel

Studies on 30Ni-20Cr stainless steels-I

Shigehiro INOUE

1961 Volume 47 Issue 14 Pages 1898-1903
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1898

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Changes of mechanical properties and corrosion loss were observed with specimens of 30 Ni-20Cr stainless steels by varying Mo, Si and Cu contents, respectively.
The following results were obtained:
(1) The higher the Mo content, the higher the tensile strength, the yield strength and the elastic limit of forged specimens. But the maximum tensile strength of cast specimens was obtained by addition of 8.8% Mo.
(2) The minimum corrosion loss in a boiling solution of 5wt.% H₂SO₄ and HCI was obtained by addition of 3-4% Mo, also the minimum grain-boundary corrosion loss was obtained by addition of 3-7% Mo.
(3) Effect of Si and Cu contents on mechanical properties and corrosion loss was less than that of Mo.

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On Chemical Composition of Secondary Phases and Behavior of Each Element by Aging in the Gamma-Type Fe-Co-Cr-Ni Base Heat-Resisting Alloy, LCN-155

Study on tempering process of γ-type heat-resisting alloys.-IV

Yunoshin IMAI, Tsuyoshi MASUMOTO

1961 Volume 47 Issue 14 Pages 1903-1911
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1903

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In the present study, the chemical compositions of secondary phases and the behavior of each element by aging after solution-treatment with the LCN-155 type heat-resisting alloys were examined by chemical analyses of residues extracted electrolytically.
The results obtained were as follows:
(1) The metallic constituents in the secondary phases after aging consisted mainly of Cr, at a lower temperature and consisted of Cr and Mo, W, and Cb with a larger atom radius at a higher temperature. With the duration of aging, the ratio of concentrations of metallic elements to C and N in the precipitates increased.
(2) The C, N, Cr, Mo, W, and Cb in the alloys were concentrated into the precipitates with the duration of aging, e. g., in the state as aged at 900°C for 168 hours the most parts of Cb, about 50% of each C and N, about 10% of each Mo and W, and about 4% of Cr in the alloy.
(3) Additions of Cb or/and N induced the changes in the partial distributions of elements, especially C, Mo, and W, into the matrix and the precipitates.
(4) In the alloys containing Cb, the undissolved Cb compound after solution treatment consisted of (Cb, Cr, Mo, W) ₄ (C, N) ₃. The precipitates in the fully age-hardened alloys were presumed to be as follows:
C-Fe-Co-Cr-Ni-Mo-W alloy (Cr₂₁Mo_1.5W_0.5) C₆:[M₂₃C₆ carbide]
C-Fe-Co-Cr-Ni-Mo-W-Cb alloy (Cr₁₈MO₂W₁Cb₂) C₆:[M₂₃C₆ carbide]
C-Fe-Co-Cr-Ni-Mo-W-N and C-Fe-Co-Cr-Ni-Mo-W-N-Cb alloys (Cr, Co, Fe, Ni) _x (Mo, W, Cb) _y (C, N), _z:[X phase]

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Effect of Elements and Heat-Treatment on the Precipitation of Ni-Base Heat-Resisting Alloys

Sadao KOSHIBA, Tsuneo KUNOU, Shin KIMURA

1961 Volume 47 Issue 14 Pages 1911-1918
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1911

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his report deals with the effect of additional elements such as Mo, Al, W, V and Nb on the precipitation, and with the behavior of the precipitation due to the heat-treatment in the Ni-base heat-resisting alloys.
The precipitates were isolated electrolytically from specimens, and chemical composition and crystalline structure of the isolated precipitates were determined by chemical analysis and X-ray diffraction, and the shape of the precipitates were observed by electron microscopy. The results obtained were as follows:
(1) The precipitates of aging-treated specimens which were added with several elements consisted of Ni₃ (Al·Ti), M₂₃C₆ and Ti (C·EN) usually, and the most portion of the precipitates was Ni₃ (Al·ETi).
Among the added elements, especially, in the case of Al or Nb addition, Ni₃ (Al·ETi) or Nb₄ (C·EN)₃ was precipitated plentifully, and the amount of precipitates, as-aged hardness and strength at high temperature of the alloys were increased conspicuously.
(2) The insoluble precipitates in solution-treated states were only Ti (C·EN).
The amount of precipitates were influenced by aging temperature, but the effect of solutiontreatment temperature were hardly observed.
The amount of precipitates was increased with the rise of aging temperature, and it showed the highest value when the specimens were aged at 800°C, but precipitates were decreased rapidly in the specimens by aging treatment at above 850°C
Presumably, it should be the result of precipitation or dissolution of Ni3 (Al·ETi) due to the degree of aging temperature.

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On the Large Steel Forgings

Masayoshi KAWAI

1961 Volume 47 Issue 14 Pages 1919-1932
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1919

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[title in Japanese]

1961 Volume 47 Issue 14 Pages 1933-1937
Published: December 01, 1961
Released on J-STAGE: December 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1933

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[title in Japanese]

1961 Volume 47 Issue 14 Pages 1938-1940
Published: December 01, 1961
Released on J-STAGE: December 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1938

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[title in Japanese]

[in Japanese], [in Japanese], [in Japanese]

1961 Volume 47 Issue 14 Pages 1941-1943
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1941

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[title in Japanese]

1961 Volume 47 Issue 14 Pages 1944-1945
Published: December 01, 1961
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.47.14_1944

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