Tetsu-to-Hagane

[title in Japanese]

[in Japanese]

1960 Volume 46 Issue 5 Pages 537-538
Published: May 01, 1960
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_537

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Operation with Self-Fluxing Sinter in the Blast Furnace

Keizi Tuzihata, Makoto Inoue, Naoto Nakamura, Masakazu Yoshinaga, Kozi ...

1960 Volume 46 Issue 5 Pages 539-548
Published: May 01, 1960
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_539

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The author performed a large-scale experimental operation of a blast furnace with self-fluxing sinter burden at No. 2 Kukioka Blast Furnace during the period from June 1958 to March 1959. Investigation of variable problems such as effectiveness of lime-sinter, optimum blast furnace operation measures for lime-sinter and other various problems for use of lime-sinter, were performed by this experimental blast furnace operation.
So remarkable results were obtained as shown in the followings by 100% self-fluxing sinter burden:
(1) The author performed productivity test during the period of December, 1958 and February, 1959 respectively. Pig iron production of more than 1, 200 ton per day was achieved during both periods. This production record corresponds to productivity factor of more than 14 ton per day per m³.
(2) Remarkable coke-ratio record of 518 kg per ton pig iron was also achieved in November 1958. The reasons for these excellent results were investigated.

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Reduction Reactions between Molten Slags Containing Titanium-Oxide and Pig Iron and the Behavior of Titanium-Oxide

Kazumi Mori

1960 Volume 46 Issue 5 Pages 548-555
Published: May 01, 1960
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_548

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The author studied the reduction of titanium and silicon from the slags of the system CaO-SiO₂-TiO₂ (TiO₂ 15, 25, 35%; CaO/SiO₂ 0.5-1.3) into carbon-saturated iron in a graphite crucible at 1550°C. The duration of each study was 75 minutes during which metal and slag samples were taken at 10 or 15 minutes intervals. K_{Ti, Si}= { [ Ti] (Si) } / { (Ti) [ Si] } was determined from the analyses. It was found that a certain time had elapsed before the quasiequilibrium state was attained, when K_{Ti, Si} reached a constant value. This constant KTi, Si is termed the index number of the quasi-equilibrium state.
The influence of slag compositions upon the contents of titanium and silicon in the iron at the same time of reduction was somewhat complicated, except that the titanium was increased with the increase of titania in the slag and the silicon was decreased with increase of CaO/SiO₂. On the contrary, it was presumed that the relationship between the index number K_{Ti, Si} slag compositions was definitely established.
At the constant titania coatents the index number K_{Ti, Si} was increased with increase of CaO/SiO₂ and at the cunst, CaO/SiO₂ it was decreased as titania was increased. Then, (CaO) / { (SiO₂) +f_T (TiO₂) } or B_L, which the author had recently given as a new scale of basicity, was taken as the basicity of the slag, and K_{Ti, Si} was plotted against the basicity. It was shown by this plot that all the points representing slags of different titania contents lay along the same line, and KTi, Si was increased with increase of the basicity.
The contents of Ti₂O₃ in the slags was decreased with increase of CaO/SiO₂. It was establi shed as a rule that in the slags containing the oxide of a transition metal such as Fe, Cr or Ti the concentration of cations with higher valency was increased with increase of slag, basicity.
Furthermore, by studying the practical data of titaniferous iron sand smelting in an elec tric furnace, it was indicated that the reduction of each element was controlled by the common degree of reduction. It was found that K_{Ti, Si}=0.658 (σ=0.097) in the range of slag basicity B_L =0 - -1.0.

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On the Stability of Molten Iron Jet through Various Shapes of Nozzles

Study of the hydrodynamics of molten steel in tapping and teeming-III

Yosaku Koike, Yozo Muto, Sozaburo Okubo

1960 Volume 46 Issue 5 Pages 556-560
Published: May 01, 1960
Released on J-STAGE: December 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_556

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In the previous research (ib., Tetsu-to-Hagané vol. 44, 1958, p. 122.), the characteristics of jets of some water solutions and mercury through the nozzles of various diameters and shapes were studied, and the flowing property of a nozzle tapered at entrance and with a short parallel straight part at outlet was better than that of normal one.
In this research, the flowing conditions of the molten iron through 20mm ∅; and 40mm ∅; practical nozzles were observed, and for both sizes of nozzles, specially tapered and nor mally designed types were examined. The results obtained were as follows:
(i) 20mm ∅; nozzle:
The condition of jets through both types of nozzles (specially tapered and normally designed) were almost the same and seemed not to be turbulent at a high head (about 900mm). The flowing properties of both type nozzles were different at a low head. Though the jets through tapered nozzles were dripping under 200mm head, the jets through normal ones dripping under 340mm head.
(ii) 40mm ∅; nozzle:
The jets through tapered nozzles did not show turbulence even at the 900mm head, but the jets through normal nozzles were thought to be turbulent above 700-750mm head. The dripping condition of jets through both tapered and normal nozzles were almost same at a low head. The dripping range of each type nozzle was very small and could not be measured clearly.
(iii) Bubble enfolded by molten iron jet:
If the molten iron jet was assumed to begin enfolding bubbles at the same Reynolds number ×ν (kinematic viscosity) where the mercury jet began to enfold bubbles, the molten iron jets through 20mm ∅; and 40mm ∅; nozzles began to enfold bubbles at 640mm and 580mm heads respectively by calculation.
Though the experiments for higher heads of a ladle and errosion of nozzle material have not been completed yet, some considerations for design of nozzles and ladles were described in conclusion based on the results of the previous and this investigations.

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Effect of W, Mo and V on the Various Properties of High-C, High-Cr Die Steel (SKD 1)

Sadao Koshiba, Kingo Kiyonaga

1960 Volume 46 Issue 5 Pages 561-566
Published: May 01, 1960
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_561

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High-C, high-Cr cold die steel (SKD 1) is widely used for punching dies and appreciated as an abr asion-resisting and a material non-deformable due to heat treatment. Lately, necessity for promoting productivity of motor or transformer core materials due to increased demands needs to further improve die life of this steel. Based on the above reason, the effect of W, Mo and V was investigated on such various properties of SKD 1, which contained the behavior of hardness, micro-structure, hardenability, distortion ratio due to heat treatment, toughness and wear resistance. Main results obtained were as follows:
(1) By addition of Mo and W to SKD 1, as-quenched hardness was increased at lower temperatures and decreased at higher temperatures. On the other hand, the addition of V showed the inverse effect.
(2) The addition of W, Mo and V increased the resistance to temper-softening of quenched specimens. This effect was in the following order: Mo>W>V.
(3) Hardenability of SKD 1 was improved by addition of these alloying elements, but the effect of Mo was much remarkable.
(4) V-contained specimens were comparatively insensitive to changes of distortion ratios due to quenching temperature.
(5) Decomposition of retained austenite due to tempering appeared in one or two stages, influenced by chemical composition of specimens. By observation on the dilatation of specimens, it was deduced that the addition of W developed the decomposition of retained austenite in the first stage of tempering, and the combined addition of Mo and V depressed this tendency.
(6) Wear resistance was improved by addition of W, Mo and V, but especially the effect was the strongest with W and the weakest with Mo.

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The Effect of Ti on High Temperature Properties of Austenitic Steel

Ryuichi Nakagawa, Yasuo Otoguro

1960 Volume 46 Issue 5 Pages 566-571
Published: May 01, 1960
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_566

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Following the previous report (Tetsu-to-Hagane 45, 1959, 11, p. 1276), the effect of Ti and C on the mechanical properties (such as creep rupture strength, tensile strength and aging hardness) and the microstructure of 18 Cr-12 Ni austenitic stainless steel containing Ti were studied.
The range of the C contents studied was from 0.06% to 0.49%, and that of the Ti contents was from 0% to 155%.
With these steels, TiC and Cr₂₃C₆ precipitated during aging at 600, 650, 700 and 750°C. The aging hardness increased with increasing C contents and decreased with increasing Ti contents.
When the Ti content was over four times as much as theC content, large granular TiC remained on grain boundaries. It seemed that this structure had a unfavorable effect on the mechanical properties.
Precipitates were examined by the same method as described in the previous report. With the specimens with 0. 06% and 0. 12% of C, X-ray diffraction lines of TiC, TiN, τ phase which seemed Ti sulfide were obtained but with the specimens with higher C contents, TiN and τ phase were not detected.
The tensile strength depended mainly upon the C content dissolved in the matrix.
When the Ti content was about four times as much as the C content, the creep rupture strength was maximum for each C content.

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Effect of Various Elements on the Properties of 2lCr -4Ni Valve Steel

Naomichi Yamanaka, Kunio Kusaka, Masanobu Kitahara

1960 Volume 46 Issue 5 Pages 571-577
Published: May 01, 1960
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_571

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To investigate the influence of C, Si, Ni, M n and N₂ on the properties of “21Cr-4Ni” valve steel, which was beginning to be used for automotive ind h ustry nowadays, the authors measured ardness change, mechanical properties at room and elevated temperature, rapture strength, magnetic permeability, oxidation resista nce in the air at elevated temperature, corrosion resistance to liquid PbO and 40% boiling HNO ₃ solution, hardness change in nitriding byNH₃ gas and carbo-nitriding by NaCN-BaCl₂ salt.
The results obtained were as follows:
(1) The as-quenched and the as-tempered hardness, the tensile and the yield strength at room temperature were increased with C contents, but the impact strength at room and elevated temperature were decreased with C contents. The corrosion resistance to liquid PbO was enhanced with C contents.
2) When Si content was (less than 0. 5%, the tensile and the rupture strength at elevated temperatures were most excellent, and the corrosion resistance to liquid PbO and 40% boiling HNO₃ solution were strong also. As Si content was increased more than 0. 5%, the corrosion resistance to liquid PbO and boiling 40% HNO₃ solution were decreased, but the oxidation resistance in the air at elevated temperatures was enhanced with Si addition.
3) The impact strength at room temperature was increased with (Ni addition, and the oxidation resistance in the air at elevated temperatures was enhanced by Ni addition.
4) The tensile strength and the yield strength at room temperature (were slightly increased with Mn contents, but the impact strength at elevated temperature was decreased by Mn addition.
5) This alloy steel was capable of nitriding by NH₃ gas, and carbo-nitriding by NaCNby BaCl₂ salt.

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Welding of Stainless Steels (II) -Review-

Haruyoshi Suzuki

1960 Volume 46 Issue 5 Pages 578-588
Published: May 01, 1960
Released on J-STAGE: December 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_578

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Progress in Blast Furnace Practice

Kamekichi Wada

1960 Volume 46 Issue 5 Pages 589-597
Published: May 01, 1960
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_589

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Present Overseas Situations in Iron and Steel Analysis

Hidehiro Goto

1960 Volume 46 Issue 5 Pages 598-602
Published: May 01, 1960
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_598

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[title in Japanese]

1960 Volume 46 Issue 5 Pages 603-611
Published: May 01, 1960
Released on J-STAGE: December 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_603

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[title in Japanese]

1960 Volume 46 Issue 5 Pages 612-616,597
Published: May 01, 1960
Released on J-STAGE: December 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_612

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[title in Japanese]

1960 Volume 46 Issue 5 Pages 617-618
Published: May 01, 1960
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_617

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[title in Japanese]

1960 Volume 46 Issue 5 Pages 623-624
Published: May 01, 1960
Released on J-STAGE: October 12, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.46.5_623

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