Steel Science Portal

Tetsu-to-Hagané
New Arrival Alert : OFF

You can use this feature after you logged into the site.
Please click the button below.

Log in / Sign up

Grid List Abstracts

ONLINE ISSN: 1883-2954
PRINT ISSN: 0021-1575

Tetsu-to-Hagané Vol. 89 (2003), No. 12

  • Activities of MnO and SiO2 in the MnO-SiO2-CrOx, Melt and Equilibrium Relation among Inclusions of This Ternary System and Molten Stainless Steel during Si-deoxidation Process

    Mitsuru TANAHASHI, Tsuyoshi TANIGUCHI, Tomohiro KAYUKAWA, Chikabumi YAMAUCHI, Toshiharu FUJISAWA

    pp. 1183-1190

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    Abstract

    The activities of MnO and SiO2 in the liquid phase region of the MnO-SiO2-CrO, x ternary system saturated with MnO·Cr2O3 solid solution were determined by conducting the equilibrium experiments between the above-mentioned ternary liquid phase and molten iron under the condition of the oxygen partial pressure, PO2=2×10-6Pa at 1873K. By using the thermodynamic data of the MnO-SiO2-CrOx system determined in the previous and the present studies by the authors, the effect of the amount of Si addition on the equilibrium oxygen concentration in molten stainless steel and the composition of non-metallic inclusions under the various conditions of Si-deoxidation process were calculated with the aid of the thermodynamic data related to molten steel. The behavior of inclusions formed during the process is discussed based on the results obtained.

  • Analysis of Steel Scrap Preheating Process by Recovery of Waste Heat in Continuous Casting

    Tao WANG, Masahiro KAWAKAMI, Kenichiro MORI

    pp. 1191-1197

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    Abstract

    A method for preheating steel scraps using waste heat in a continuous casting process was proposed. Experiment and numerical analysis were carried out to examine the ability of scrap preheating and to determine the factors affecting the rise in scrap temperature. The commercial FEM software ANSYS was used for simulation of temperature distributions in the scrap. The simulated results agreed well to the experimental ones with the emissivities of heat source and samples of 0.85 and 0.65, respectively. The thickness (Hs) of the scrap sample and the distance (D) between the heat source and sample were found to affect the rise in sample temperature largely. The overall heat transfer can be given by the following dimensionless relation:
    Nu0=[(5.505D*H*0.75-0.403)Ra0.18t*-1-26.21(D*H*)1/3+9.96]×(1+0.268D*-2.19H*-0.73)
    A higher preheating efficiency is anticipatable to combine the proposed method with the conventional ways of scrap preheat using waste gas.

  • Effect of Pore Structure of Coke on CO2 Reactivity and Abrasion of Coke

    Hidekazu FUJIMOTO, Shozo ITAGAKI, Izumi SHIMOYAMA, Kiyoshi FUKADA, Tatsuro ARIYAMA

    pp. 1198-1204

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    Abstract

    Improvement in coke strength against abrasion is needed for a stable operation of blast furnace. Pore structure of coke (e.g. pore size distribution and tortuosity) is important for an improvement of coke abrasion strength, because its effect influences CO2 diffusion coefficient and coke strength after CO2 reaction. In this study, production of coke samples having different pore structure was attempted by blending different size of slightly caking coal to coal blend. The effect of pore structure on CO2 reactivity and abrasion after CO2 reaction was investigated.
    In case that larger size (2-3 mm) slightly caking coal was added to coal blend and carbonized (Coke A), the pore size distribution of coke became wider and contained larger pore which had higher value of tortuosity than the coke produced by adding smaller size (1-2 mm) slightly caking coal particles (Coke B). Difference in pore structure is considered to be originated by bubble size generated during softening of coal particles. Relationship between pore size and tortuosity is caused by the quantity of bottle-neck type pores in coke.
    The reactivity of Coke A was higher and the extent of the reaction at inner part of coke lump analyzed by X-ray computerized tomography was larger, compared with the Coke B. These differences are considered to be based on the fact that large pore enhances diffusion of CO2 into inner part of the coke, and that concentration of shear stress easily occurs around large pores.

    Recommended Articles: Behavior of Dioxins in the Sintering Process of Iron Ores [ View more ]

    x

    Readers Who Read This Article Also Read

    1. Behavior of Dioxins in the Sintering Process of Iron Ores Tetsu-to-Hagané Vol.87(2001), No.5
    2. Grinding Sludge Recycling to Reduce Environmental Load (Investigation of Relation between Machine Characteristic and Grinding Sludge Briquetting Condition) Tetsu-to-Hagané Vol.93(2007), No.3
    3. Effect of Coal Interaction on Coke Strength Tetsu-to-Hagané Vol.87(2001), No.5

  • Effect of Atmospheric Gas Composition on Reaction Behavior of Low Porosity Carbon Composite Iron Ore Pellet

    Yasuaki UEKI, Takayuki MAEDA, Masakata SHIMIZU, Yoshiyuki MATSUI, Akito KASAI

    pp. 1205-1211

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    Abstract

    The reaction behavior of low porosity carbon composite pellet produced by hot briquetting process was examined under various gas atmospheres such as N2, CO and 50vol%CO-50vol%CO2. The reduction reaction was affected largely by atmospheric gas at low temperature, and affected small at high temperature. On the other hand the gasification of coal was affected by not atmospheric gas but temperature. The effect of atmospheric gas on the reaction behavior was explained by variation of pressure in sample during reaction. The reactions in nitrogen gas atmosphere above 1000°C were controlled by the gasification of coal. Therefore, kinetic analysis in nitrogen gas atmosphere was carried out by using the first order reaction model. The temperature dependencies of reaction rate constants for the gasification of coal obtained by kinetic analysis were as follows.
    kCC=exp(5.51-130×103/RT)
    kC2=exp(5.67-160×103/RT)

    Recommended Articles: Behavior of Dioxins in the Sintering Process of Iron Ores [ View more ]

    x

    Readers Who Read This Article Also Read

    1. Behavior of Dioxins in the Sintering Process of Iron Ores Tetsu-to-Hagané Vol.87(2001), No.5
    2. Grinding Sludge Recycling to Reduce Environmental Load (Investigation of Relation between Machine Characteristic and Grinding Sludge Briquetting Condition) Tetsu-to-Hagané Vol.93(2007), No.3
    3. Effect of Coal Interaction on Coke Strength Tetsu-to-Hagané Vol.87(2001), No.5

  • Reduction and Carburization of Carbon Composite Iron Ore Hot Briquet on Condition of Increasing in Temperature

    Akito KASAI, Masaaki NAITO, Yoshiyuki MATSUI, Yoshiaki YAMAGATA

    pp. 1212-1219

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    Abstract

    Carbon composite iron ore hot briquet was new material for ironmaking and was made by binder-less briquetting in use of thermal plasticity of coal. Physical and chemical properties of the briquet were low slag rate, low porosity and high crushing strength without curing in comparison with carbon composite iron ore cold bonded pellet.
    In this paper, application of the briquet to shaft furnace was discussed. In order to clarify reduction and carburization of the briquet on condition of increasing in temperature, reduction experiments were carried out. The following results were obtained.
    (1) During reduction, crushing strength of the briquet did not decrease in widely difference from cold bonded pellet.
    (2) In heat-up reduction tests under load, reduction and carburization of the briquet occur in lower temperature in comparison with sinter and iron ore pellet.
    (3) Using the briquet in blast furnace simulator, temperature of thermal reserve zone decrease and CO gas utilization increase in comparison with sinter. It was expected that reaction efficiency of lumpy zone in blast furnace was improved by using the briquet.

    Recommended Articles: Cold Strength Enhancement Mechanism of Carbon Composite Iron Ore Hot Briquet [ View more ]

    x

    Readers Who Read This Article Also Read

    1. Cold Strength Enhancement Mechanism of Carbon Composite Iron Ore Hot Briquet Tetsu-to-Hagané Vol.87(2001), No.5
    2. Behavior of Dioxins in the Sintering Process of Iron Ores Tetsu-to-Hagané Vol.87(2001), No.5
    3. Grinding Sludge Recycling to Reduce Environmental Load (Investigation of Relation between Machine Characteristic and Grinding Sludge Briquetting Condition) Tetsu-to-Hagané Vol.93(2007), No.3

  • Genetic Algorithm with Reduction of Search Space Using Operational Constraints and Its Application to Scheduling System for Steelmaking Process

    Satoshi FUJII, Sunao TANIMOTO, Shinji TOMIYAMA, Ryosuke KIMURA, Masaaki SHIRAI, Hiroaki MIYAHARA

    pp. 1220-1226

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    Abstract

    This paper describes an automatic scheduling system for steelmaking process from refining converter to continuous caster. Conventionaldaily scheduling system does not get an optimal solution automatically, but gets a feasible solution with no machine conflicts between processes. It is very difficult to get the optimal solution for the large-scale and complex problem of steelmaking process scheduling, because this scheduling involves particular constraints and varying production requirements of each process. The proposed scheduling procedure consists of optimal method by using modified genetic algorithm (GA). This method applies multi-constraints to the reduction of the search space obtaining feasible solutions. And it can suppress the calculation time. The system has two benefits. One is an extension of the weekly scheduling system from the daily one. The other is an improvement in the quality of the schedule. The cost effectiveness is low waiting time of secondary refining process and low changing of alternative secondary refining process. This algorithm was installed in the scheduling system of NKK Keihin Works and has contributed to improving its efficiency in the steelmaking process.

    Recommended Articles: 第58回講演大会講演大要14 [ View more ]

    x

    Readers Who Read This Article Also Read

    1. 第58回講演大会講演大要14 Tetsu-to-Hagané Vol.45(1959), No.9
    2. Formation Process of White Etching Area under Rolling Contact in Bearing Steel Tetsu-to-Hagané Vol.89(2003), No.7
    3. 日本鉄鋼協会第57回講演大会講演大要13 Tetsu-to-Hagané Vol.45(1959), No.3

  • Aluminizing Treatment of Mild Steel Using Aluminum Foil

    Tomohiro SASAKI, Takao YAKOU

    pp. 1227-1232

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    Abstract

    To obtain the ductile and corrosive coating treatment for steel, the aluminizing treatments using aluminum foil on mild steel surface were performed at diffusion temperature from 700 to 1000°C. The foil aluminized steels had less voids in diffusion layers, than the hot-dip aluminized steels. The foil aluminized steels at diffusion temperature not higher than 800°C had a thinner brittle layer of aluminum rich intermetallic Fe2Al5, and that at diffusion temperature not lower than 900°C had thicker layers of iron rich intermetallics such as FeAl and Fe3Al. It was found that the three body abrasive wear rates of aluminized steels with FeAl and Fe2Al that diffused at not lower than 900°C against free SiC grains were smaller wear rate than those of the steels diffused at higher than 800°C.

    Recommended Articles: 第58回講演大会講演大要14 [ View more ]

    x

    Readers Who Read This Article Also Read

    1. 第58回講演大会講演大要14 Tetsu-to-Hagané Vol.45(1959), No.9
    2. Formation Process of White Etching Area under Rolling Contact in Bearing Steel Tetsu-to-Hagané Vol.89(2003), No.7
    3. 日本鉄鋼協会第57回講演大会講演大要13 Tetsu-to-Hagané Vol.45(1959), No.3

  • Grain Refinement of High Strength Low Alloy TRIP-aided Ferrous Steels by Thermomechanical Processing in α+γ Region

    Koh-ichi SUGIMOTO, Akira HAYAKAWA, Tomohiko HOJO, Shun-ichi HASHIMOTO, Shushi IKEDA

    pp. 1233-1239

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    Abstract

    The effects of thermomechanical processing in an α+γ region on microstructure and retained austenite characteristics were investigated to enhance the workability limit of a newly developed high strength low alloy TRIP-aided ferrous steel. Ultra fine polygonal ferrite grains of 1 to 2 μm in diameter were formed inside prior martensite lath structure with interlath retained austenite plates or needles when the steels with martensite single phase were subjected to 30-50% reduction at intercritical annealing temperatures between 760 and 800°C, followed by austempering at 375-425°C for 100 s. It was confirmed by EBSP analysis that some of the ultra fine polygonal ferrite grains possessed a large difference in orientation from neighboring grains. Under the same conditions, volume fraction of retained austenite was significantly increased with a small decrease in its carbon concentration, compared to the steel subjected to only heat treatment. The refining of polygonal ferrite grain was principally caused by interlath austenite plates or needles suppressing the grain growth of polygonal ferrite recrystallized just after intercritical reduction.

    Recommended Articles: 第58回講演大会講演大要14 [ View more ]

    x

    Readers Who Read This Article Also Read

    1. 第58回講演大会講演大要14 Tetsu-to-Hagané Vol.45(1959), No.9
    2. Formation Process of White Etching Area under Rolling Contact in Bearing Steel Tetsu-to-Hagané Vol.89(2003), No.7
    3. 日本鉄鋼協会第57回講演大会講演大要13 Tetsu-to-Hagané Vol.45(1959), No.3

  • Relation between Creep Rate during Accelerating Creep Stage and γ Channel Thickness in Single Crystal Nickel-based Superalloy, CMSX-4

    Nobuhiro MIURA, Yoshihiro KONDO, Takashi MATSUO

    pp. 1240-1247

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    Abstract

    To elucidate the origin of the onset of accelerating creep in a single crystal nickel-based superalloy, CMSX-4, the correlation between the creep rate during the accelerating creep stage and the thickness of γ channel was investigated by using the single crystals crept at 1273K in a wide stress range of 100-400 MPa. The shape of γ' phase and the thickness of γ channel at the time of the onset of accelerating creep turn to different ones with decreasing the stress. At the stress of 160 MPa, the cuboidal γ' phase turns its shape to a rafted one. While at the stresses less than 160 MPa the rafted γ' phase appears before the onset of accelerating creep. At the stresses higher than 250 MPa, the cuboidal γ' phase still remains. The correlation between the thickness of γ channel, λγ and the creep rate during the accelerating creep stage, ε, was evaluated, and the following equation, ε∝λ4 γ is proposed and confirmed in a wide stress range of 100-400 MPa, independent of the shape of γ' phase. In addition, it was also confirmed that the radius of dislocation curvature within γ channel of the crept specimens was proportional to the thickness of γ channel defined by TEM.
    Consequently, the origin of the onset of accelerating creep in a single crystal nickel-based superalloy was interpreted by the loss of creep resistance due to an increase in the thickness of γ channel, λγ.

  • Creep Damage at Fine Grained Heat Affected Zone of Seam Welded Cr-Mo Steel Pipes and a Proposed Mechanism of Its Origination and Growth

    Hideshi TEZUKA

    pp. 1248-1254

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    Abstract

    A seam welded Cr-Mo steel pipe elbow that had been used as main steam piping at a thermal power plant was investigated. Creep damages at fine grained heat affected zone of the seam weld, called as type IV damages, were observed. Hook-shaped microcracks surrounded by many polygonal hollows were observed by optical microscopy and scanning electron microscopy. Those polygonal hollows were seemed to form the same hook-shaped lines as microcracks. Fine bainite grains surrounded by coarse carbides and creep cavities were also lined in the same manner as the hollows. From the appearances of the hook, it was inferred that these damages were originated locally at the former austenite grain boundaries.
    Dense precipitations of carbides (DPCs) were found on extraction replicas by transmission electron microscopy. At the beginning of the usage, there might be high-carbon-content fine bainite grains and DPCs were created in these grains by aging. Because of the similarities in shapes, sizes and distributions, DPCs were regarded as root causes of the hollows and the cracks. Many creep cavities would appear at DPCs and fine bainite grains would easily be isolated. As DPCs line on the former austenite grain boundaries, exfoliated fine bainite grain boundaries would link each other to form a microcrack.
    In order to suppress type IV damage, it would be effective to avoid the origination of fine bainite with high-carbon-content grains on the former austenite grain boundaries. Adding normalizing twice or more to the heat treatment process for the plate materials before welding is proposed.

    Recommended Articles: 第58回講演大会講演大要14 [ View more ]

    x

    Readers Who Read This Article Also Read

    1. 第58回講演大会講演大要14 Tetsu-to-Hagané Vol.45(1959), No.9
    2. Formation Process of White Etching Area under Rolling Contact in Bearing Steel Tetsu-to-Hagané Vol.89(2003), No.7
    3. 日本鉄鋼協会第57回講演大会講演大要13 Tetsu-to-Hagané Vol.45(1959), No.3
  • © 2003 The Iron and Steel Institute of Japan

Article Access Ranking

17 Jan. (Last 30 Days)

  1. A Review of the Chemistry, Structure and Formation Conditions of Silico-Ferrite of Calcium and Aluminum (‘SFCA’) Phases ISIJ International Vol.58(2018), No.12
  2. Improving Blast Furnace Raceway Blockage Detection. Part 1: Classification of Blockage Events and Processing Framework ISIJ International Advance Publication
  3. Phase Transformation Behavior of Oxide Scale on Plain Carbon Steel Containing 0.4 wt.% Cr during Continuous Cooling ISIJ International Vol.58(2018), No.12
  4. Hydrogen Embrittlement Susceptibility Evaluation of Tempered Martensitic Steels Showing Different Fracture Surface Morphologies Tetsu-to-Hagané Vol.105(2019), No.1
  5. Heat Transfer Characteristic of Slit Nozzle Impingement on High-temperature Plate Surface ISIJ International Advance Publication
  6. Gasification and Migration of Phosphorus from High-phosphorus Iron Ore during Carbothermal Reduction ISIJ International Vol.58(2018), No.12
  7. Effect of Coke Size on Reducing Agent Ratio (RAR) in Blast Furnace ISIJ International Vol.58(2018), No.12
  8. Improvement of Sinter Productivity by Control of Magnetite Ore Segregation in Sintering Bed ISIJ International Vol.58(2018), No.12
  9. High Temperature Thermal Diffusivity Measurement for FeO Scale by Electrical-Optical Hybrid Pulse-Heating Method ISIJ International Vol.58(2018), No.12
  10. Effect of TiO2 and MnO on Viscosity of Blast Furnace Slag and Thermodynamic Analysis ISIJ International Vol.58(2018), No.12

Search Phrase Ranking

17 Jan. (Last 30 Days)

  1. blast furnace
  2. blast furnace productivity
  3. blast furnace permeability
  4. 鉄と鋼
  5. continous annealing
  6. laser welder
  7. titanium
  8. activity feo
  9. argon steel
  10. eaf operation