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

Tetsu-to-Hagané Vol. 101 (2015), No. 11

  • Water Model Study of Viscosity Effect on Mold Powder Entrapment

    pp. 559-565

    Bookmark

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

    Log in / Sign Up

    DOI:10.2355/tetsutohagane.TETSU-2015-049

    Water model experiments were carried out to understand the mechanism of mold powder entrapment. The main objective is to clarify an effect of the viscosity of mold powder on the entrapment. Water and silicone oils of different viscosities were used as the working fluids. Onset of the entrapment was judged by eye inspection and using a high-speed camera. The critical water flow velocity at the interface was measured with a laser Doppler velocimetry (LDV) to describe the onset condition. The results were compared with a previously proposed analytical equation without containing the viscosity effect to highlight the effect.
  • The Conditions of Ettringite Formation by the Reaction of a Blast Furnace Slag with Aqueous Alkaline Solutions

    pp. 566-573

    Bookmark

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

    Log in / Sign Up

    DOI:10.2355/tetsutohagane.TETSU-2015-053

    Blast furnace (BF) slags have been utilized in cement, concrete aggregate, roadbed materials, and earthwork materials. If an appropriate control of the elution and compound formation is developed under severer environmental conditions, their usage would be more diverse. Because the chemical composition of BF slag is similar to that of Portland cement, the possibility of ettringite (3CaO·Al2O3·3CaSO4·32H2O) formation from BF slag following a mechanism similar to that of cement hydration might be possible under a wet alkaline environment. Therefore, the effect of an alkaline solution on ettringite formation from BF slags was investigated by slag-leaching experiments and thermodynamic calculations using PHREEQC. The formation of ettringite was observed only for the high pH solutions in the experiments, whereas its thermochemical possibility from the air-cooled BF slags was always expected by the calculation. The kinetic analysis showed that the dissolution of alumina from the slag may control the whole reaction rate. The mixing of granulated BF slag with air-cooled ones tended to enhance the ettringite formation. Furthermore, a technique for removing the ettringite formed in the slag was also developed.
  • Development of Stochastic Model of Production Time and Estimation Technology for Standard Production Time in a Plate Mill

    pp. 574-583

    Bookmark

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

    Log in / Sign Up

    DOI:10.2355/tetsutohagane.TETSU-2015-024

    Accurate estimation of the standard production time in steel plate mills is crucial for making successful production plans. Due to the complicated and stochastic processes of the steel plate mills, it is challenging and time-consuming to build precise mechanistic models which enable the estimation of the precise production time. To overcome this limitation, we propose a method to estimate the accurate standard production time from the historical process data instead of mechanistic models. In our method, decision trees are employed to identify the process flow for each order. Then the probability distribution of the process time for each process is computed by means of the maximum likelihood estimation. These probability distributions are combined into one probability distribution of the total production time in accordance with the predicted process flow. Finally, the standard production time is defined as the corresponding time with cumulative density function of the probability distribution at the specified confidence level. Real world steel production process data have been used to examine the effectiveness of the proposed approach. The results demonstrate that the new standard production time can increase the rate of production completion no later than the deadlines as well as shorten the average production time one to three days.
  • Effect of Both Iron Content and Lubricated Layer on the Sliding Performance of Galvannealed Steel Sheet

    pp. 584-589

    Bookmark

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

    Log in / Sign Up

    DOI:10.2355/tetsutohagane.TETSU-2015-027

    The effect of iron content of zinc layer and lubricated layer on sliding performance of the galvannealed steel sheets (GA) was investigated.
    The effect of iron content on friction coefficient for lubricated GA was dependent on the sliding condition. For the condition in which the contact pressure is high, the friction coefficient increased with the increase of iron content of GA. However, for the condition in which the pressure is low, the friction coefficient decreased with the increase of iron content. This tendency of the friction coefficient was also observed in the fender model press forming test.
    When the contact pressure is high, more oil pockets were formed on the surface due to the increase of the plateau area. Therefore, the friction coefficient decreased since the partial pressure was sustained in the oil pockets. Since the GA coating with low iron content is softer than that with high iron content, the friction coefficient of lubricated GA increased with the increase of iron content.
    On the other hand, when the contact pressure is low, the oil pocket was not formed on the surface. In addition, the lubricated layer is easily worn since the tool length is long and the lubricant surface is more damaged than in the case of short length tool. Therefore, the friction coefficient is affected by the adhesion between tool and GA surface. This is why the tendency of iron content on friction coefficient for GA and lubricated GA is similar.
  • Effect of Initial Ni Plating on the Structure and Hardness of Electrodeposited Ni-W Alloys with and without Annealing

    pp. 590-597

    Bookmark

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

    Log in / Sign Up

    DOI:10.2355/tetsutohagane.TETSU-2015-050

    Electrodeposition of Ni-W alloys was conducted from an unagitated sulfate solution containing citric acid at pH 5 and 60 °C under coulostatic (9.0×105) and galvanostatic (100-5000 A·m–2) conditions onto steel sheets with an initial Ni plating, and the effect of initial Ni plating on the structure and hardness of deposited Ni-W alloys was investigated before and after annealing. The precipitates of Ni4W and NiW were observed in deposits obtained at all the current densities after annealing, irrespective of having undergone initial Ni plating or not. Without initial Ni plating, a lot of large precipitates occurred in the vicinity of steel substrate, while the fine precipitates occurred with initial Ni plating. Without initial Ni plating, the W content in deposits increased in the vicinity of steel substrate due to diffusion of Ni in deposits into steel substrate during annealing. With initial Ni plating, the W content in deposits in the vicinity of Ni plating decreased due to diffusion of Ni in Ni plating into deposits during annealing. Before annealing, W content in deposits was lower with initial Ni plating than that without Ni plating. With initial Ni plating, W content in deposits was lower and Ni diffused from Ni plating to deposits during annealing, as a result, the formation of large precipitates of Ni4W and NiW seems to be suppressed. The hardness of deposited Ni-W alloys after annealing increased when the precipitates of Ni4W and NiW became uniform and fine.
  • Effect of Annealing Duration on the Structure and Hardness of Electrodeposited Ni-W alloys

    pp. 598-604

    Bookmark

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

    Log in / Sign Up

    DOI:10.2355/tetsutohagane.TETSU-2015-051

    Electrodeposition of Ni-W alloys was conducted from an unagitated sulfate solution containing citric acid at pH 5 and 60 °C under coulostatic (9.0×105) and galvanostatic (100-3000 A·m–2) conditions onto steel sheets with an initial Ni plating to investigate the effect of annealing duration on the structure and hardness of deposited Ni-W alloys. The crystallite size of Ni in deposits with several seconds annealing increased significantly compared to without annealing, and gradually increased with annealing duration. With increasing the holding time at 700 °C to 100 and 1000 s, the precipitates of Ni4W and NiW were increased and became coarse at upper layers of deposits. The hardness of all the deposits increased with annealing, and the degree of increase became significantly large with increasing W content in deposit by increasing current density. The hardness of deposit with W content 45 mass% was maximum at holding time of 10 s at 700 °C, and gradually decreased with increasing annealing duration. The hardness of deposits increased when the precipitates of Ni4W and NiW were uniformly distributed in a fine size, which showing the optimum precipitation state at holding time of 10 s at 700 °C.
  • Characteristic Fatigue Crack Growth Behavior of Low Carbon Steel Under Low-pressure Hydrogen Gas Atmosphere in an Ultra-low Frequency

    pp. 605-610

    Bookmark

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

    Log in / Sign Up

    DOI:10.2355/tetsutohagane.TETSU-2015-018

    In order to clarify an influence of hydrogen on the fatigue crack propagation in ultra-low frequency region, we investigated the crack propagation rates of S10C at different frequencies in hydrogen and nitrogen atmospheres. In the low-pressure hydrogen gas atmosphere, the crack propagation rate decreased with decreasing in frequency within the present experimental range. In particular, the crack propagation rate in the ultra-low frequency (10–3 Hz) became the same as that in nitrogen atmosphere. To explain the disappearance of the hydrogen effect in the ultra-low frequency, we proposed that carbon diffusion causing strain-age hardening also contributes to the decrease in crack propagation rate in the ultra-low frequency under the hydrogen atmosphere.
  • Recrystallization Behavior and Texture Evolution in Severely Cold-rolled Fe-0.3Mass%Si and Fe-0.3Mass%Al Alloys

    pp. 611-618

    Bookmark

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

    Log in / Sign Up

    DOI:10.2355/tetsutohagane.TETSU-2015-043

    The effect of Si and Al additions on the recrystallization behavior of severely cold-rolled Fe by 99.8% reduction was investigated in comparison with a previous study on pure Fe6). In Fe-0.3mass%Si alloy, recrystallized grain with {411} <011> and {411} <148> preferentially nucleated at an early stage of recrystallization, and the texture did not changed substantially with the progress of recrystallization, which supports the oriented nucleation theory. The {411} <148> texture significantly increased at the expense of recrystallized grains with {100} <023> and {322} <236> during normal grain growth. In Fe-0.3mass%Al alloy, dynamic recovery during heavy cold-rolling and substantial subgrain growth during low temperature annealing (350˚C) occurred, similar to the case of pure Fe and different from that of Fe-0.3mass%Si alloy. This is presumably because of the subtle influence of Al addition on cross-slip frequency and smaller solute-vacancy interaction as compared with Si addition. Furthermore, at the early stage of recrystallization, nuclei had similar orientations as cold-rolling texture. With the progress of recrystallization, {100} <012> and {111} <112> orientations intensified. In the following normal grain growth, {100} <012> texture intensified. However, the change in the texture during growth cannot be explained only by the size effect. A rigorous grain growth simulation model is required to explain the experimental facts by considering the dependency of grain boundary mobility and energy on grain boundary characteristics.
  • Effect of One-Pass ECAP prior to Cold Rolling on the Deformation Structure and Recrystallization in Ferritic Stainless Steel Sheets

    pp. 619-625

    Bookmark

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

    Log in / Sign Up

    DOI:10.2355/tetsutohagane.TETSU-2015-047

    Equal-channel angular pressing (ECAP) was applied to ferritic stainless steel sheets for one pass prior to cold rolling in order to improve formability and alleviate ridging of the sheets. Effect of the channel angle of ECAP (90° and 120°) on the deformation microstructure and the subsequent recrystallization was focused. One-pass ECAP indeed modified the cold-rolled microstructures, texture and subsequent recrystallization as compared with that in cold rolling alone. In particular, grain-scale shear bands are introduced during ECAP in otherwise hard-to-recrystallize <100>//ND grains by ECAP, and they facilitated the recrystallization. However, the effect of reducing the channel angle from 120°to 90°on the recrystallization and the formability was limited in spite of higher shear strain imposed on the sheets. The reduction of the channel angle affects an increase of misorientation between the shear band and the matrix and does not increase the density of shear band.

Article Access Ranking

19 Mar. (Last 30 Days)

  1. Dependence of Carbon Concentration and Alloying Elements on the Stability of Iron Carbides ISIJ International Advance Publication
  2. Comprehensive Optimization Control Technology of Rolling Energy and Oil Consumption in Double Cold Rolling ISIJ International Advance Publication
  3. Experiments on Removal of Hydrophilic Fine Particles in Bubbly Flow ISIJ International Vol.59(2019), No.2
  4. Effects of Impurities and Processing Conditions in Al–1%Mn Alloys on the Formation of Thermally Stabilized Substructures MATERIALS TRANSACTIONS Vol.59(2018), No.11
  5. Coating Film Profiles Generated by Fluctuating Location of the Wiping Pressure and Shear Stress ISIJ International Vol.59(2019), No.2
  6. Temperature Field Distribution of a Dissected Blast Furnace ISIJ International Advance Publication
  7. Effect of Nut Coke Addition on Physicochemical Behaviour of Pellet Bed in Ironmaking Blast Furnace ISIJ International Advance Publication
  8. Evolution of Blast Furnace Process toward Reductant Flexibility and Carbon Dioxide Mitigation in Steel Works ISIJ International Vol.56(2016), No.10
  9. Effect of EAF Slag Temperature and Composition on its Electrical Conductivity ISIJ International Vol.59(2019), No.2
  10. Fundamentals of Silico-Ferrite of Calcium and Aluminium (SFCA) Iron Ore Sinter Bonding Phase Formation: Effects of Basicity and Magnesium on Crystallisation during Cooling ISIJ International Vol.59(2019), No.2

Search Phrase Ranking

19 Mar. (Last 30 Days)

  1. blast furnace
  2. blast furnace productivity
  3. blast furnace permeability
  4. galvanizing
  5. 鉄と鋼
  6. tuyere abrasion
  7. tuyere erosion
  8. isij
  9. lme
  10. tuyere failure