Tetsu-to-Hagane

Carbon Equivalent, Maximum Hardness and Cracking in Welding Steel

Haruyoshi SUZUKI

1984 Volume 70 Issue 16 Pages 2179-2187
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2179

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Acoustic Emission Source Characterization and Its Application to the Study of Dynamic Micro-cracking

Takanori OHIRA, Teruo KISHI

1984 Volume 70 Issue 16 Pages 2188-2195
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2188

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Present Status of Stainless Steel Sheet for Railway Rolling Stock

Masayoshi OGAYA

1984 Volume 70 Issue 16 Pages 2196-2203
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2196

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Standard Test Method for Threshold Stress Intensity Factor K_ISCC in Stress Corrosion Cracking (JSPS 129 Committee Recommendation)

Takao AOKI, Tadao IWADATE

1984 Volume 70 Issue 16 Pages 2204-2207
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2204

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Study of Primary Melt Formation and Transition Mechanism to Final Slag of Sintered Ore

Ichiro SHIGAKI, Mineo SAWADA, Osamu TSUCHIYA, Kunihiro YOSHIOKA, Tasuk ...

1984 Volume 70 Issue 16 Pages 2208-2215
Published: December 01, 1984
Released on J-STAGE: February 16, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2208

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Liquidus temperatures, obtained by quenching technique, were measured for mixtures in the system CaO-SiO₂-Al₂O₃-Fe₃O₄in 10^-7 atm atmosphered P_O₂. Analysis of final silicate slag of sintered are by use of EPMA revealed that chemical compositions lay in the field near the pseudowollastonite-dicalcium eutectic line between 1 250°C and 1 300°C in the phase diagram.
An interrupted sintering pot test and sintering simulation experiments of the mixture of raw materials showed that there were two kinds of primary melts, which were liquid silicate and liquid calcium ferrite. Liquid calcium ferrite generated two kinds of structures; one consisted of quarternary calcium ferrite and silicate slag, and the other was mainly composed of dicalcium silicate and dicalcium ferrite or magnetite.
With increasing temperature, primary silicate melt of low basicity dissolves dicalcium silicate and becomes final slag of higher basicity.

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Studies on Some Aspects of Deterioration of Coke in Blast Furnace

Hiroshi HARAGUCHI, Tetsu NISHI, Yoshiaki MIURA, Miyoshi USHIKUBO, Tami ...

1984 Volume 70 Issue 16 Pages 2216-2223
Published: December 01, 1984
Released on J-STAGE: February 16, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2216

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Based on the results of dissection of Nagoya BF No.1, studies were conducted on the degradation of coke in a large blast furnace. The results of these studies show the following facts. 1) The degradation of coke in blast furnaces is greatly influenced by the temperature at which coke is subjected to CO₂ reaction. 2) The lump coke, which begins to degrade due to selective solution loss and to decrease its strength at 1 000°C, does not change its grain size up to 1 400°C but begins to reduce it sharply above 1 400°C. 3) The coke fines depositing between the lower part of the shaft and the tuyeres are generated in the vicinity of the raceway and move there by the kinetic energy of the blast. 4) The increase in the alkali content of coke (by 5% maximum in the present study) does not decrease the strength of coke.
Further, the relationship between the inner volumes of Nippon Steel's dissected blast furnaces and the changes in coke size in these furnaces was studied. It is suggested that the coke particle size reduction ratio is higher and the coke degradation conditions are severer in large blast furnaces than in small ones.

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Flow of Iron in Blast Furnace Hearth

Masaharu TACHIMORI, Jiro OHNO, Masakazu NAKAMURA, Yukiaki HARA

1984 Volume 70 Issue 16 Pages 2224-2231
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2224

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Fundamental aspects of the hot metal flow in the blast furnace hearth during tapping have been studied for the better control of the hot metal flow to prolong furnace life.
Blast furnace hearth is regarded as a packed bed of coke with considerably good permeability in terms of metal flow. Characteristics of metal flow in a hearth have been analysed by using the numerical calculation, as well as, model experiments.
Equal velocity lines in an uniformly packed hearth are formed on vertical cyrindrical surfaces of which central axis coincides with the position of a tap hole. The flow velocity at a center of hearth is about 0.1cm/s. If a coke free space is formed at the bottom of hearth, flow pattern varies remarkably. The flow velocity in a coke free space of 10cm thickness is more than 10 times of the velocity for uniform bed, and more than 50% of hot metal is drained through it. The velocity in the space decreases remarkably with the increase of the depth of the space The velocity in a space of 40 cm deep is reduced to the same level as that for the uniform flow.

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The Reducing Dephosphorization of Molten Stainless Steel and Slag Treatment

Toshiaki ARATO, Tetsuro UCHIDA, Yoshifumi OMORI

1984 Volume 70 Issue 16 Pages 2232-2238
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2232

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The dephosphorization of molten stainless steel by the addition of metallic Ca has been studied by using a laboratory scale high frequency furnace and industrial scale electric arc furnace. In addition, safety treatments of dephosphorization slag were examined.
The results obtained are summarized as follows:
(1) In a laboratory scale test, the relation between activities of C and O (a_C and a_O) of molten steels and dephosphorization ratios were found. Optimum conditions where dephosphorization ratios reached more than 50% were a_C<0.92 and a_O<4×10^-4 at 1 480°C.
(2) In order to obtain the optimum condition of 18Cr8Ni steel, it was necessary to control carbon and oxygen contents in the range of 0.3%<C<1.0% and O<60 ppm at 1 480°C, respectively.
(3) In the industrial scale experiment on 13Cr5Ni steel, dephosphorization ratio and desulfurization ratio were 33% and 55%, respectively, by the addition of Ca=10.6 kg per ton steel.
(4) Concentrations of PH₃ and H₂S generating from dephosphorization slag were measured. Maximum concentrations were 160 ppm/g for PH₃ and 400 ppm/g for H₂S before safety treatment. After the safety treatment by using oxide slag, maximum concentrations decreased to 2 ppm/g for PH₃ and 11 ppm/g for H₂S.

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Practical Shape Meter for Hot Strip Mill

Sadao KAWASHIMA, Saburo TSURUTANI, Kiyoshi HIRATA, Eisuke TANAKA, Take ...

1984 Volume 70 Issue 16 Pages 2239-2245
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2239

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A practical shape meter to measure the manifest shape of running strip on a hot strip mill line with high accuracy has been developed. Structures and operating results of the meter are reported.
The points of designing were getting good stability of an eddy current type displacement meter, protecting sensor heads and sensor positioning mechanism, and so on. Moreover the following functions were given; automatic sensor positioning, remote calibration of the displacement meter, statistical data processing of steepness data, and communication to a process computer.
From the results of performance in Kakogawa Works, measuring accuracy of ±0.16% in steepness and time between failures more than 100 00 h have been obtained.

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Experimental Determination of Isothermal Section in a Ni-Cr-W Ternary System at 1 000°C

Makoto KIKUCHI, Masanori KAJIHARA, Yoshikuni KADOYA, Shu-ichi TAKEDA, ...

1984 Volume 70 Issue 16 Pages 2246-2253
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2246

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An isothermal section of an equilibrium phase diagram in a Ni-Cr-W ternary system was experimentally determined at 1 000°C. Seventeen alloys with multiphase composition were equilibrated at 1 000°C for more than 10 000 h. Three terminal solid solutions: fcc γ nickel-rich, bcc α₁chromium-rich and bcc α₂ tungsten-rich phase, and two intermetallic compounds: β-Ni₄W and σ phase, were observed as stable phases. Two-phase tie-lines and three-phase tie-triangles were determined by means of an electron microprobe analysis.

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Effects of Heat Treatment and Chemical Composition on Intergranular Embrittlement Phenomena in Ultra-low-carbon Low-alloy Steels

Masakazu NIIKURA, Sadahiro YAMAMOTO, Chiaki OUCHI, Isao KOZASU

1984 Volume 70 Issue 16 Pages 2254-2261
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2254

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Effects of metallurgical factors on grain boundary embrittlement phenomena in ultra-low-C low-alloy steels (basic composition; 0.025C-2Mn-0.05Nb-Ti-B) were systematically investigated. Intergranular fracture in the low temperature Charpy test apparently occurred in ultra-low-C Nb-contained steels reheated in the temperature range of 600-700°C, which have the microstructure of martensite and/or bainite with a coarse prior austenite grain size 150μm.
Either decrease of C content or increase of Nb content enhanced the intergranular embrittlement, and intergranular fracture occurred in the C range lower than a critical carbon content which increased with niobium content. Carbon segregation on the prior austenite grain boundaries was revealed by Auger electron spectroscopy for the steels and segregated carbon content was found to decrease remarkably in the lower-carbon steels and the higher-niobium steels. There was a consistent correlation between the fractional increase of intergranular fracture appearance and the decrease of segregated C content.
The same mechanism for intergranular fracture as in pure iron was considered to operate in the steels. The general conditions for the intergranular embrittlement and effects of P content, B content and the prior austenite grain size were also discussed.

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Prevention of the Intergranular Fracture in Iron-Phosphorus Alloys by Carbon

Shigeru SUZUKI, Minoru OBATA, Kenji ABIKO, Hiroshi KIMURA

1984 Volume 70 Issue 16 Pages 2262-2268
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2262

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Fe-P alloys with up to 0.67wt% phosphorus show intergranular fracture (IGF) by impact test after quenched from 1 073 K. Addition of carbon up to about 0.01wt% to the alloys prevents the intergranular fracture caused by the grain boundary segregation of phosphorus, and lowers the ductile-brittle transition temperature (DBTT). This effect is due to the segregation of carbon to grain boundaries. Aging at 873 K of the quenched specimen with 0.52%P and 0.0008%C reduces DBTT and increases the degree of grain boundary segregation of carbon while it does not affect the degree of grain boundary segregation of phosphorus. The grain boundary segregation of carbon increases the grain boundary cohesion and prevents the intergranular fracture without removing phosphorus from grain boundaries.
DBTT's of the Fe-P-C alloys are analyzed in terms of the degree of grain boundary segregation of carbon and phosphorus and the solution hardening by phosphorus (the bulk concentration of phosphorus). The site-competition between carbon and phosphorus is taken into account in the calculation of the degree of segregation. It is found that the increase in the boundary cohesion by the carbon segregation is an important factor to prevent IGF.

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Damping Capacity of Composite Sheets Made by Superplastic Rolling/Joining Technique of Steel-Superplastic Alloy

Akira AZUSHIMA, Tsunemasa MIURA, Matsuo MIYAGAWA

1984 Volume 70 Issue 16 Pages 2269-2275
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2269

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A study has been conducted to develop the composite sheets made by superplastic rolling/joining technique of steel-superplastic alloys which could be used for the damping material at high temperature. The superplastic alloys used were Zn-22%Al alloy, Al-6%Cu-0.5%Zr alloy and Al-12.9%Mg₂Si alloy and the composite sheets consisted of the three layers of steel and superplastic alloy (e. g. steel-s. p. alloy-steel, s. p. alloy-steel-s. p. alloy). In case of Zn-22%Al alloy, the volume percentage of the alloy was changed at five steps of 0, 25, 50, 75 and 100%. The specimens were rolled at 4 or 5 passes at 200°C and the final reduction became 80%. The laminar and granular structures could be obtained by heat treatments after rolling. In case of the other alloys, the volume percentage of the alloys was 50%. The specimens were rolled at 300°C and the final reduction became 80%. The results obtained were as follows;
(1) The damping capacity of the steel-Zn-22%Al alloy composite sheet could be obtained several times values of the steel in room temperature. The damping capacity increased with increasing temperature. Above the temperature of 200°C, the damping capacity exceeded 0.1.
(2) In the composite sheets of steel-Al superplastic alloys, good formability could be obtained by heat treatment.

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Design of a Composite Damping Sheet Made by Superplastic Rolling/Joining Technique of Steel-Superplastic Alloy

Akira AZUSHIMA, Matsuo MIYAGAWA

1984 Volume 70 Issue 16 Pages 2276-2281
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2276

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In a previous paper, the composite sheets made by superplastic rolling/joining technique of steel-super-plastic alloy were developed and it was found that they could be used for the damping material at high temperature. On the basis of these results, a study has been conducted to investigate the damping mechanism of the composite sheet and the design of the composite damping sheet of steel-superplastic alloy. The effect of the joining interface of the composite sheet on damping capacity could not be recognized. It became possible that the damping capacity of the composite sheet was calculated from each damping capacity characteristic. The damping capacity calculated from a simple model was generally in agreement with the measured one. From the calculated results, when the layer number of the composite sheets was five, the best damping capacity was obtained.

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Development of Covered Arc-welding Electrode for Austenitic Heat-resisting Steel (0.1C-2Si-24Cr-13Ni-0.8Mo-0.25N)

Rokuro FUJIMOTO, Shuichiro MIZOGUCHI

1984 Volume 70 Issue 16 Pages 2282-2288
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2282

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Purpose of this study is to develop covered arc-welding electrode for austenitic heat-resisting steel with high nitrogen concentration, 0.1C-2Si-24Cr-13Ni-0.8Mo-0.25N.
In order to prevent hot cracking of weld metal and to keep heat-resisting properties of weld metal equal to those of base metal, covered arc-welding electrode for HK40(0.4C-25Cr-20Ni), which includes less than one percent of Si in all-deposited weld metal, was chosen.
Effects of two kinds of coverings, lime-titania and lime, on blowhole in weld metal, crack-resisting properties of weld metal and creep rupture properties of welded butt joint at 1 000°C were investigated.
A lime-type covered arc-welding electrode which prevented blowhole in weld metal and excelled in crack-resisting properties of weld metal and creep rupture properties of welded butt joint could be successfully developed.
Chemical composition of all-deposited weld metal of this welding electrode is as follows; 0.4C-0.75Si-25Cr-20Ni-0.10V-0.02Nb-0.02Ti-0.04O-0.0005H-0.09N.
Various properties of welded butt joint of the above heat-resisting steel are also described in this article.

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Infrared Thickness Sensor of Paint Film

Shiro HAMADA, Kiyoshi AWAI, Keiji YAMAMOTO, Masaharu HIRATA

1984 Volume 70 Issue 16 Pages 2289-2293
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2289

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For the quality control of colored sheets, a film thickness sensor applied to a coil coating line has been developed. The thickness is related to the amount of infrared energy absorbed in the film. Infrared reflectivity of coated coils in the two wavelengths is measured in order to obtain an accurate thickness with reducing the errors caused by the variation of steel surfaces.
Continuous and noncontact measurement of coated film thickness has been made within an accuracy of ±0.3 μm of σ for primer films of about 6 μm in thickness and of ±1.0 μm of σ for top films of about 20 μm in thickness.

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[title in Japanese]

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

1984 Volume 70 Issue 16 Pages 2293-2293,2324
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2293

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The Development of "Macro Analyzer" and Its Application to Steel Analysis

Koicki KITAMURA, Katsuhiro KAWASHIMA, Hiromu SOGA, Hiroyuki OGAWA, Tsu ...

1984 Volume 70 Issue 16 Pages 2294-2300
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2294

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Two-dimensional quantitative quick analyzing method has been expected for the accurate evaluation of the segregation and inclusions in steel.
A new electron probe large area mapping analyzer("Macro analyzer"), that permits rapid and accurate two-dimensional analysis of elements even for the large sample(300×100 mm) with the undulation inherent to it, has been developed. This has been achieved by the development of a long-focus electron optics, a broad-view X-ray spectrometer, and a high-speed sample stage. This system was automatically operated with a control computer and at the same time the obtained two-dimensional data were processed with a data processing computer and shown on a color graphic display. By the development of this system, a new quantitative evaluation method of segregation and inclusions in continuously cast slabs and steel materials was established.
In this paper, as an example of the use of this system, quantitative characterization of small segregation spots in a lamellartear resistant steel was studied.

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Aging of Powdered Sample and Its Influence on Free Nitrogen Analysis by Constant Temperature-Hydrogen Hot Extraction Method

Yoshiro TAKIZAWA, Toshihiko HATA, Yoshihide ENDO

1984 Volume 70 Issue 16 Pages 2301-2304
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2301

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Determination of free nitrogen in steel by constant temperature-hydrogen hot extraction method was studied and optimum analytical conditions were established.
1) Lower measured values were obtained with samples that had passed for long time after powdering. 2) The result of 1) was considered to come from the fact that dissolved nitrogen in steel was locked to dislocations and/or formed cluster gradually, thus becoming difficult to be extracted. 3) Higher temperature of environment around samples accelerated these effects, so it must be avoided to heat powdered samples for washing and drying. 4) It is necessary to analyse samples of finer powders soon after powdering. 5) When the sample was analysed under these analytical conditions, free nitrogen could be fully extracted at 400°C.

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[title in Japanese]

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

1984 Volume 70 Issue 16 Pages 2305-2306
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2305

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[title in Japanese]

[in Japanese]

1984 Volume 70 Issue 16 Pages 2307-2308
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2307

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[title in Japanese]

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

1984 Volume 70 Issue 16 Pages 2313-2317
Published: December 01, 1984
Released on J-STAGE: June 30, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.70.16_2313

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