Tetsu-to-Hagane

[title in Japanese]

[in Japanese]

1978 Volume 64 Issue 1 Pages 1-2
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_1

JOURNAL FREE ACCESS

Download PDF (1519K)
Production and Technology of Iron and Steel

in Japan during 1977

Tsuneyo IKI

1978 Volume 64 Issue 1 Pages 3-24
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_3

JOURNAL FREE ACCESS

Download PDF (6387K)
Removal of Fine Particles in Ores for Blast Furnace by Pneumatic Classifier of Horizontal Type

Natsuo HATTA, Jun-ichi KOKADO

1978 Volume 64 Issue 1 Pages 25-33
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_25

JOURNAL FREE ACCESS

Show abstractHide abstract

A pneumatic classifier of horizontal type is used instead of the wire sieve in order to eliminate fines in ores charged into blast furnace. The former is very convenient because it is free from troubles such as choking of the meshes and the breakdown in the case of the wire sieve. The removal of fines in sintered ores with increasing the mixing ratio (feed quantity to air quantity) was experimentally and theoretically examined in consideration of the scattering of the apparent specific weight and drag coefficient for the particles.
The results obtained are as follows:
(1) The classification is effectively carried out in when a distinct difference in horizontal travelling distance according to particle size can be made, even if the apparent specific weight and drag coefficient scatter in some extent.
(2) With increasing the mixing ratio, the classification accuracy is lowered due to increasing of the collision frequency among the particles within the classification region. It is possible to avoid to some extent by thinning the thickness of feed particle bed.
(3) The removal of fines is considerably successful by decreasing the cross section area of duct and increasing the air velocity in the case of classifing under condition of the same feed quantity and the same air quantity.
(4) For the increase of the mixing ratio, it is practically economical to shorten the height of the duct and to make a calm zone within the classifing region without lowering the classification accuracy remarkably.

View full abstract

Download PDF (1788K)
Effects of Electric and Magnetic Forces on the Solidified Structure

Shigeo ASAI, Kenzi YASUI, Iwao MUGHI

1978 Volume 64 Issue 1 Pages 34-41
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_34

JOURNAL FREE ACCESS

Show abstractHide abstract

To clarify the effects of the electric and magnetic forces on the solidified structure, the solidification experiments were systematically conducted on the Sn-10%Pb alloy. A direct or an alternative electric currents, magnetic currents and the currents combined them were introduced into the molten metal. The alloy was solidified under the nine different conditions.
The effects of the electric field, the magnetic field and the combined field on each solidified structure were examined on the basis of the solidified structure and the theoretical considerations of the fluid flow caused under each experimental condition.
It is concluded that the columnar structure can be developed by preventing the fluid flow and the fine equi-axed zone can be obtained by the forced fluid flow.

View full abstract

Download PDF (6328K)
Estimation of Solute Concentration Distribution Accompanied by Interdendritic Solidification

Kazuo WATANABE

1978 Volume 64 Issue 1 Pages 42-51
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_42

JOURNAL FREE ACCESS

Show abstractHide abstract

A peculiar break point in the cooling curves was experimentally observed. This point may be resulted from the rapid progress of solidification caused by the supercooling of interdendritic liquid.
For studying the mechanism mentioned above mathemaical models for estimating the distribution of the solute concentration in the interdendritic liquid have been developed. The models are described for three cases where the liquid-solid interface is plain, cylindrical surface, and spherical one, respectively. Two models for the second and the third cases, which represent the state of the liquid surrounded with the dendrite arms, show that the difference between the liquid concentrations at the liquid-solid interface and those at the midpoint of adjacent dendrites increase when the solid fraction increases at the constant ratio. And it may be understood that the concentration difference results in the supercooling. While for the first model the difference of the concentrations decreases.
Furthermore, by the use of the third model the measured temperatures where the break point occurs can be explained.

View full abstract

Download PDF (3249K)
Effect of Nitrogen Content on Deep Drawability of Rimmed Low Carbon Cold Rolled Steel Sheet

Masashi TAKAHASHI, Atsuki OKAMOTO, Shingo INO, Tadaaki NAKATA

1978 Volume 64 Issue 1 Pages 52-59
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_52

JOURNAL FREE ACCESS

Show abstractHide abstract

In the production of rimmed steel sheet, its nitrogen content converged to a constant level at box annealing process. Therefore increased nitrogen in steel making did not affect the strain aging properties of the sheet, but deteriorated the drawability or the r-value of the sheet.
To clarify the effect of nitrogen on recrystallization texture formation, the nitrogen content at cold rolling and that at recrystallization annealing were varied by atmospheric reaction at 350-400°C after cold rolling and then recrystallization textures were compared. Amounts of {111} and {110} components of the recrystallization texture were markedly affected by the nitrogen content at annealing, whereas they were not affected by that at cold rolling. Meanwhile, neither the amount of {100} component nor recrystallized grain size was influenced by nitrogen content.
It was supposed that high nitrogen content at the ladle in steel making induced larger amounts of nitrogen atoms as interstitials at recovery or recrystallization stage of the cold rolled steel, which promoted the recrystallization of {110} component and suppressed the development of {111} component at recrystallization annealing.

View full abstract

Download PDF (2305K)
The Effect of Warm Tensile Working on the Stress Relaxation Value in the Carbon Steel

Nobuyuki NAKAZAKI, Yosuku KOIKE, Jirou NAMEKATA

1978 Volume 64 Issue 1 Pages 60-69
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_60

JOURNAL FREE ACCESS

Show abstractHide abstract

In order to clarify the effect of warm tensile working on the stress relaxation value ΔP/P0 (ΔP: relaxed load, P0: initial load) at room temperature in a carbon steel (ferrite+lamellar pearlite), the effect of predeformation temperature (20°C-320°C), strain and structure have been studled, The results obtained are as follows:
(1) The decrease in the stress relaxation value is observed on specimens which predeformed in the temperature rahge from about 220°C to 270°C. These predeformation tcmperature correspond to the temperature where the strain aging increases with increasing dissolution of the iron nitride and carbide owing to predeformation.
(2) When the lamellar cementite have partially been broken by the predeformation in the temperature range from 20°C to 220°C, the relation between the relaxation value and logarithmic time is a snaky curve and then the relaxation value is shown its maximum value.
(3) While the linear relation is observed for the steel with bended and broken lamellar cementite, in this case the relaxation value increases proportionally with increasing predeformation strain.

View full abstract

Download PDF (6169K)
Heat Transfer Phenomena in Immersion Cooling of Heated Steel Plate and Influence of Water Stirring on Heat Transfer

Masashi MITSUKA, Keiji FUKUDA

1978 Volume 64 Issue 1 Pages 70-77
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_70

JOURNAL FREE ACCESS

Show abstractHide abstract

When an immersion method is used for the cooling of heated steel products, it is important that the characteristics of this method are made clear. In order to measure the values of heat transfer coefficient between a specimen and coolant, and to clarify the influence of coolant stirring on heat transfer, 28×550×1000mm³ steel plates of about 930°C have been immersed into still water or stirred water.
The main results obtained are summarized as follows:
(1) When a specimen is immersed vertically into water, the maximum of heat transfer coefficient between the specimen and water (α) is, in kcal/mm2·h·deg, (5-7) ×10³ for still water, (7-9) ×10³ for stirred water by air flow, and (10-12) ×10³ for stirred water by water flow.
(2) In a vertical immersion into still water, α is considered to be a function of the surface temperature of a specimen, θ_s, and the height from the lower edge, H, as indicated below.
α=10^(a+b·θ_s)· [1.0-k (H-10)]
Where a, b, and k are constants which depend on θ_s.
(3) When a specimen is immersed vertically into still water, αdecreases with increasing the size of the specimen.
(4) The stirring of coolant by fluid flow is effective for the accelaration of the heat transfer and the water flow method is superior to the air flow one.

View full abstract

Download PDF (2059K)
Static Tensile Properties of Mixed Structure of Martensite and Residual Ferrite in Ni-Cr-Mo Steels Containing Medium Carbon

Yoshiyuki TOMITA, Sachio OKI, Kunio OKABAYASHI

1978 Volume 64 Issue 1 Pages 78-87
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_78

JOURNAL FREE ACCESS

Show abstractHide abstract

A study has been made to clarify the effect of residual ferrite on static tensile properties of Ni-Cr-Mo steels containing medium carbon. Results obtained are summarized as follows:
(1) The 0.2% proof stress approximately follows the calculated law of mixture up to 14% of residual ferrite, but becomes to deviate significantly from it beyond 14%.
(2) Both elongation and reduction in area remarkably decrease with an increase in residual ferrite.
(3) From the analyses of true stress-strain diagrams and microfractographs, a detrimental effect on ductility results from the fact that, in low volume fraction of residual ferrite, microcracks are initiated by fracturing of the residual ferrite in a brittle manner due to higher plastic restraining of it by martensite in the process of plastic deformation, and that with increasing in the residual ferrite microcracks which are initiated by fracturing of it, this mainly resulting from stress concentration in the neiborhood of interfaces between martensite and residual ferrite due to ununiform deformation, become to be simultaneously propagated through embrittled martensite.

View full abstract

Download PDF (5305K)
Precipitation Hardening Produced by Ausaging of 245kg/mm² Grade 18% Ni Maraging Steel

Ko SOENO, Tetsuro KURODA

1978 Volume 64 Issue 1 Pages 88-94
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_88

JOURNAL FREE ACCESS

Show abstractHide abstract

Ausaging behavior in 245kg/mm² grade maraging steels has been investigated. Appreciable precipitation-hardening is produced by ausaging at temperatures below about 625°C. The precipitation hardening is considered to be due to relatively high titanium content. It is also observed that elongation and reduction of area are decreased with increasing ausaging temperature. The decrease in ductility is considered to be caused by the formation of coarse precipitates at the austenite grain boundaries. The coarse precipitates are greatly suppressed when ausaging temperature is decreased to about 550°C. After ausaging at 550°C from 3000min to 6000min, the following mechanical properties are obtained; ultimate tensile strength: 200-210kg/mm², elongation: 10-15%, reduction of area; 60-65%. However, the ductility of specimens ausaged at 550°C for longer times tends to decrease because of the formation of relatively coarse precipitates at the austenite grain boundaries.

View full abstract

Download PDF (3303K)
Precipitation of Intermetallic Compounds in Austenite and Its Effects on Toughness of As-Quenched Martensite in 13%Ni Maraging Steel

Koji HOSOMI, Yoshio ASHIDA, Hiroshi HATO, Kazunori ISHIHARA, Hitoshi N ...

1978 Volume 64 Issue 1 Pages 95-104
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_95

JOURNAL FREE ACCESS

Show abstractHide abstract

The precipitation of intermetallic compounds in austenite and its effects on the toughness of as-quenched martensite in 13%Ni maraging steel have been studied by means of Charpy impact tests and structural observations. The heat-treatment process investigated comprises intermediate isothermal holding in the temperature range from 800°C to 1100°C after homogenization at 1200°C reheating of the martensite to the austenite region below 1100°C after quenching to room temperature from 1200°C.
Not only the intermediate holding but also the reheating introduced a drastic decrease in Charpy impact energy of the as-quenched martensite. Structural observations revealed the coarse precipitates on prior austenite grain boundaries and within the grains for both heat-treatments. Prolonged intermediate isothermal holding was necessary to cause the precipitation within the grains. However, when the martenisite was reheated to the range between Af and the austenite recrystallization temperature, the precipitation within the grains was promoted in short time, due to the presence of the nucleation sites formed in martensite on the heating up to the austenitic region, or probably to the internal strains of the reverted austenite.
These precipitates were considered to be intermetallic compounds of Fe₂Mo or (Fe, Co) ₇Mo₆. The major loss in the toughness of as-quenched martensite of 13%Ni maraging steel was associated with the precipitation of intermetallic compound containning Mo during holing in the austenite regions.

View full abstract

Download PDF (9833K)
The Effect of Second Phase Particles on the Tensile Properties of Ferritic Iron at Low Temperature

Ryuichi HAMANO, Kazuo TSUYA

1978 Volume 64 Issue 1 Pages 105-112
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_105

JOURNAL FREE ACCESS

Show abstractHide abstract

The effect of two kinds of the finely dispersed particles with different elastic modulus from iron matrix (∈-Cu and TiN) on the low temperature ductility of ferritic iron was investigated.
∈-Cu particles were uniformly dispersed in the matrix by aging of Fe-1.83% Cu allay at 700°C for 96h, whereas TiN particles were uniformly dispersed by internal nitriding of Fe-0.1% Ti alloy at 700°C for 4h. By the presence of TiN particles, the elongation at 77K of ferritic iron with 150μ grain diameter increased by about 20%, whereas, by the presence of ∈-Cu particles, the elongation at 77K of ferritic iron with 60μ grain diameter decreased by about 20%. The reason is considered that the presence of TiN particles favors cross slip of screw dislocation around these particles which changes the deformation mode of coarser grained ferritic iron from twinned to slipped, whereas ∈-Cu particles do not work so.

View full abstract

Download PDF (6191K)
The Influence of Solution and Precipitation Behavior of M₂₃ (C, B) ₆ on the Hardenability of Boron Steels

Seiichi WATANABE, Hiroo OHTANI, Tatsuro KUNITAKE

1978 Volume 64 Issue 1 Pages 113-120
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_113

JOURNAL FREE ACCESS

Show abstractHide abstract

Cu-Ni-Cr-Mo-B low alloy steels whose total boron content exceeds a certain limit show superior hardenability when they are austenitized at lower temperatures (≤900°C), although their hardenability decreases with higher austenitizing temperatures and longer holding times. As M₂₃ (C, B) ₆ in these steels is partly undissolvable at lower austenitizing temperatures, B content in solid solution is not determined uniquely from Fe-B-Al-N equilibrium state but rather regulated by the solubility product of M₂₃ (C, B) ₆.
At lower temperatures (≤900°C) boron content in solid solution which balances with M₂₃ (C, B) ₆ is considered appropriate for hardenability. At higher temperatures (>900°C), boron content in solution which equilibriates with M₂₃ (C, B) ₆ increases and exceeds the limit over which the hardenability of boron steels decreases. Heating below Ac1 for a long period, while M₂₃ (C, B) ₆ is enriched with C, Mn, and Mo atoms, austenitizing condition appropriate for the hardenability is transferred to higher temperatures and longer periods. This is because the solubility product of M₂₃ (C, B) ₆ is lessened and the particles grow coarsed.
Boron content in solid solution which balances with M₂₃ (C, B) ₆ is determined approximately from the relation among the decrease of hardenability, quenching temperature, and boron content in solution calculated from the Fe-Al-B-N system. The result is as follows: 880°C-3ppm, 900°C-6ppm and 930°C-8ppm.
These values are considered to depend strongly on Cr, Mn, and Mo contents and prior heat treating history. In excess boron containing steels, boron constituents are observed on the prior austenite grain boundaries at distances longer than 15mm from the quenched end of Jominy end quench test specimens, when they are quenched from 930°C.

View full abstract

Download PDF (4330K)
Reduction Test of Hematite Ore Powder by Gas Flowing High Pressure DTA Method

Yasunori NISHIKAWA, Yoshinobu UEDA, Sogo SAYAMA, Shigeru UEDA, Shinich ...

1978 Volume 64 Issue 1 Pages 121-127
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_121

JOURNAL FREE ACCESS

Show abstractHide abstract

The effect of reduction condition of hematite ore (32-60mesh) under high pressure (0-100kg/cm²) H₂ flow was studied using dynamic gas flow type high pressure DTA equipment. Besides usual nonisothermal DTA method, new attempt on isothermal DTA method was made by the equipment.
The results obtained are as follows:
(1) The rate of reduction was high when reduction temperature was raised from 500°C to 850°C. The lowering of reduction rate around 700°C, which was pointed out in some papers, was not observed.
(2) The effect of an increase of H₂ pressure on reduction rate became very small at a pressure upper than 15kg/cm². The effect of H₂ pressure was relatively large under a reduction condition of low temperature and low gas pressure.
(3) The rate of reduction increased with increasing H₂ (STP) gas flow rate. It was found that the effect of gas flow rate on the rate of reduction was remarkably larger than the effect of gas pressure under the experimental conditions in this study.

View full abstract

Download PDF (1509K)
Mechanical Properties of 12% Cr Steel Forging for Large Steam Turbine

Mitsuo KAWAI, Kanji KAWAGUCHI, Hiroshi YOSHIDA, Ei KANAZAWA, Satoru MI ...

1978 Volume 64 Issue 1 Pages 128-134
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_128

JOURNAL FREE ACCESS

Show abstractHide abstract

In order to develop a new rotor forging, for compact designed larger steam turbine, which has higher mechanical properties than 1Cr-1Mo-0.25V rotor at elevated temperature, an investigation has been carried out on the mechanical properties and the uniformity of 12Cr-Mo-V-Ta-N model rotor and high and intermediate pressure rotor for 375 MW steam turbine.
12Cr-Mo-V-Ta-N rotor has better room temperature tensile strength and impact value than 1Cr-1Mo-0.25V rotor, in the part of shaft, body surface and body center. Creep rupture strength of 12Cr-Mo-V-Ta-N rotor, one of the most important properties, is also higher than 1Cr-1Mo-0.25V rotor and it uniformity is excellent.
It is expected that a newly developed 12Cr-Mo-V-Ta-N rotor with good mechanical properties andsoundness can be applicable for larger steam turbine.

View full abstract

Download PDF (4491K)
LNG Tank-Its Structure, the Materials and Welding Techniques

Yasunosuke OGAWA, Mitsuhiro SAKAMOTO, Kiyoaki TOYOMASU, Mitsuo OHYAMA, ...

1978 Volume 64 Issue 1 Pages 135-144
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_135

JOURNAL FREE ACCESS

Download PDF (2164K)
Controlling Sulfide Shape with Rare Earths or Calcium during the Processing of Molten Steel

Koji SANBONGI

1978 Volume 64 Issue 1 Pages 145-154
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_145

JOURNAL FREE ACCESS

Download PDF (3254K)
Preparation and Quality Test of Minor Element Series B of Japanese Standards of Iron and Steel

Sen-ichi HARIMAYA

1978 Volume 64 Issue 1 Pages 155-164
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_155

JOURNAL FREE ACCESS

Download PDF (1580K)
A Future Trend of Research and Development in Steel Industry of Japan

Shin-ichi NAGASHIMA

1978 Volume 64 Issue 1 Pages 165-170
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_165

JOURNAL FREE ACCESS

Download PDF (1627K)
Some Impressions in USA and Canada

Masao KANAO

1978 Volume 64 Issue 1 Pages 171-174
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_171

JOURNAL FREE ACCESS

Download PDF (1407K)
[title in Japanese]

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

1978 Volume 64 Issue 1 Pages 175-179
Published: January 01, 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_175

JOURNAL FREE ACCESS

Download PDF (1360K)
Erratum to : Absorption of Sulphur from Gas Phase to Liquid Slags under Reducing Atmasphere

1978 Volume 64 Issue 1 Pages N17
Published: 1978
Released on J-STAGE: February 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.64.1_N17

JOURNAL FREE ACCESS

Download PDF (102K)

Register with J-STAGE for free!