1. |
Max‐Planck‐Institut für Eisenforschung GmbH ‐ Part 5: Department of Process Metallurgy |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 7,
2016,
Page 285-295
Hans‐Jürgen Engell,
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摘要:
The department of process metallurgy, headed by Professor Dr. H.‐J. Engell, investigates steel making processes, solidification technology and advanced metallic materials.
ISSN:0003-8962
DOI:10.1002/srin.198700223
出版商:Wiley
年代:2016
数据来源: WILEY
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2. |
Thermodynamics of antimony, arsenic, and tin in CaO—CaF2melts |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 7,
2016,
Page 296-302
Tomoo Isawa,
Takashi Wakasugi,
Kei Noguchi,
Nobuo Sano,
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摘要:
In view of the importance of tramp element contamination of steel products through a large volume of scrap consumption in the near future, the thermodynamic behaviour of Sb, As, Sn and Cu in CaO—CaF2melts under reducing conditions was studied by examining the dependences of distribution of each element between Cu, Ag or Sn alloys and CaO—CaF2melts on the CaO activity, oxygen partial pressure and temperature around 1 500°C.As a result, the reaction products on treatment by Ca compounds were demonstrated to be Ca3Sb2, Ca3As2, Ca2Sn and CaCu. Experimentally obtained distributions were extrapolated to lower oxygen partial pressures less than 10−18atm to estimate the feasibility of removing those tramp elements from molten iron. It is thermodynamically indicated that if the prevailing oxygen partial pressure of the environment is below 10−23atm, these impurities, except Cu, would be substantially removed from molten steel.
ISSN:0003-8962
DOI:10.1002/srin.198700224
出版商:Wiley
年代:2016
数据来源: WILEY
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3. |
Fundamentals of nitrogen transfer in gas‐metal bath systems during nitrogen injection |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 7,
2016,
Page 303-309
Eberhard Steinmetz,
Piotr R. Scheller,
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摘要:
This publication derives basic principles of mass transfer between nitrogen gas and metallic melts. Equilibrium solubility in multi‐component alloys can be calculated using known relations.To examine the question of the driving force for mass transfer, we first accept the usual treatment found in literature, namely that the concentration‐difference is responsible for mass transfer. In agreement with some earlier studies, it is suggested, however, that the activity difference or difference in chemical potential of nitrogen in co‐existing phases should be used to represent the driving force. Both models apply both to diffusion‐controlled mass transfer and to mass transfer occurring due to reaction at the interface.Calculated mass transfer for a bubble rising in a metal bath indicates that a very intensive mass transfer may be expected. This is confirmed in industrial practice.
ISSN:0003-8962
DOI:10.1002/srin.198700225
出版商:Wiley
年代:2016
数据来源: WILEY
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4. |
Kinetics of mass transfer during nitrogen injection in industrial Fe—Cr—Ni—Mo‐melts |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 7,
2016,
Page 310-318
Eberhard Steinmetz,
Piotr R. Scheller,
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摘要:
Experiments on the injection of nitrogen into Fe—Cr—Ni—Mo alloys in 30 t VOD‐Iadles have been carried out. The nitrogen contents obtained by nitrogen injection were between 0.05 and 0.17% for an initial nitrogen content of about 0.02%. Calculations of mass transfer associated with a rising nitrogen bubble indicate very high mass transfer rates for different nitrogen activities. The high efficiency of nitrogen gas measured in industrial practice agrees with these calculations. The specific interface area increases proportionally with the gas flow rate.According to reports in literature, nitrogen mass transfer can be described either as a 1st or 2nd order reaction. Both possibilities have been examined and the experimental results evaluated accordingly. In order to make possible a comparison with literature rate constants were first determined using comparable methods, i.e. on the assumption that the concentration difference is the driving force for mass transfer. The rate constants depend on the composition of the alloy. Assuming spherical cap bubbles with an equivalent diameter of 2.5 cm, the mass transfer coefficient was estimated to be about 5 to 8.10−3cm s−1, using a 1st order reaction model; the apparent activation energy then has a value of about 100 kJ/Mol. If a 2nd order reaction model is assumed, the apparent activation energy has a value of about 125 kJ/Mol. Using the activity difference as the driving force for mass transfer, it was found that the kinetics of mass transfer in multi component alloys could be treated in a homogeneous manner. The mass transfer coefficient calculated in this way for a 1st order reaction lies between about 26 to 37.10−3cms−1and the actual activation energy has a value of about 25 kJ/Mol. The evaluation of the experimental results using a second order reaction model gives an equally good correlation between the rate constants and the gas flow rate as that obtained using a 1st order reaction model.In this case the actual activation energies determined are slightly higher ‐ 40 kJ/Mol. However, the activation energies in both cases (i.e. with or without regard to the nitrogen activity) do not lie in the range of activation energies associated with a process controlled by interface reactions. Due to the low concentrations, it is not possible to make a definite statement about the order of the reaction. However, the activation energies determined fit better to a 1st order reaction model. Relations have been derived which, assuming a 1 st order reaction, and taking into account the composition of the alloy, enable prior calculation of suitable parameters for nitrogen injections in industrial melts. This allows a more precise process control.
ISSN:0003-8962
DOI:10.1002/srin.198700226
出版商:Wiley
年代:2016
数据来源: WILEY
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5. |
Theoretical study of the effect of asymmetries on the cold rolling process |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 7,
2016,
Page 319-326
Reiner Sauer,
Oskar Pawelski,
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摘要:
In cold rolling of strip, geometrical, kinematical, and tribological asymmetries in the roll gap can exert an influence on roll force and torque. For its calculation the elementary theory of rolling is modified. The statics on the strip element are described in polar coordinates. The effects of non‐horizontal strip entry and of different diameters of the upper and lower work roll are investigated in detail.
ISSN:0003-8962
DOI:10.1002/srin.198700227
出版商:Wiley
年代:2016
数据来源: WILEY
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6. |
Dilatothermy ‐ a new quantitative research method for allotropic transformation |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 7,
2016,
Page 327-335
Nicole Lambert,
Robert Colin,
Mario Economopoulos,
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摘要:
The authors have developed a mathematical heat treatment model which allows to take into account the exothermal effect of allotropic transformation and to predict the microstructure of heated products. In this model, the cooling law of the product is calculated by a numerical integration of the “Fourier” equation taking into account the internal heat production due to the allotropie transformation. The process of this transformation has to be known as kinetics equations. To reach this aim, the authors have developed a new method of studying the allotropie transformation and have it applied to different recrystallised carbon steels. The method consists of two steps: experimental and numerical. From the experimental point of view, a new technique, dilatothermy, has been developed. It consists of realising simultaneously a thermal analysis and a dilatometrie one on the same specimen and of benefitting from the advantages of both methods. From the numerical point of view, the results of dilatothermy tests are treated in order to find a complete mathematical model of transformation comprising, for each microstructure, and equation describing transformation kinetics, the value of transformation heat and the mean transformation temperature of each constituent.The validity of the heat treatment model has been checked by both computation and laboratory tests. Some application cases have been considered. It is shown that the models are applicable to all types of thermal treatment carried out industrially. They allow the calculation of the steel temperature, the amount of each microstructural constituent and the temperature range in which they were formed.
ISSN:0003-8962
DOI:10.1002/srin.198700228
出版商:Wiley
年代:2016
数据来源: WILEY
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7. |
News from the Max‐Planck‐Institut für Eisenforschung GmbH |
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Archiv für das Eisenhüttenwesen,
Volume 58,
Issue 7,
2016,
Page 336-338
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ISSN:0003-8962
DOI:10.1002/srin.198700229
出版商:Wiley
年代:2016
数据来源: WILEY
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