1. |
Calcium desulfurization equilibrium in liquid iron |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 10,
2016,
Page 403-409
Ryo Inoue,
Hideaki Suito,
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摘要:
Sulfur distribution ratios between CaO‐Al2O3slags and liquid iron were measured at 1873 K as a function of aluminum content using an alumina or a lime crucible. Activity coefficients of CaS relative to a solid standard state were obtained as 52&2.6 and 23&1.7 for the CaO‐Al2O3slags saturated with an Al2O3and a CaO crucible, respectively, in the concentration range up to the CaS solubility limit. From these results, logarithm of the equilibrium constant, logKCaS, for the calcium desulfurization reaction CaS(s) =Ca+Sand the first‐order interaction parametereSCa(eSCa) were estimated to be –8.72&0.27 and –269&28 (–336&35), respectively.
ISSN:0003-8962
DOI:10.1002/srin.199401184
出版商:Wiley
年代:2016
数据来源: WILEY
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2. |
Phase relations in the system CaO‐SiO2‐ZrO2at 1573 K |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 10,
2016,
Page 410-413
Pandit S. Shashidhara,
Jacob K. Thomas,
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摘要:
Zirconia‐based solid electrolytes with zircon (ZrSiC4) as the auxiliary electrode have been suggested of sensing silicon concentrations in iron and steel melts. A knowledge of phase relations in the ternary system MO‐SiO2‐ZrO2(M = Ca, Mg) is useful for selecting an appropriate auxiliary electrode. In this investigation, an isothermal section for the phase diagram of the system CaO‐SiO2ZrO2at 1573 K has been established by equilibrating mixtures of component oxides in air, followed by quenching and phase identification by optical miroscopy, energy disperse analysis of X‐rays (EDAX) and X‐ray diffraction analysis (XRD). The equilibrium phase relations have also been confirmed by computation using the available thermodynamic data on condensed phases in the system. The results indicate that zircon is not in thermodynamic equilibrium with calcia‐stabilized zirconia or calcium zirconate. The silica containing phase in equilibrium with stabilized zirconia is Ca3ZrSi2O9. Calcium zirconate can coexist with Ca3ZrSi2Og and Ca2SiO4.
ISSN:0003-8962
DOI:10.1002/srin.199401185
出版商:Wiley
年代:2016
数据来源: WILEY
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3. |
Kinetic model for reduction of iron oxide in molten slags by iron‐carbon melt |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 10,
2016,
Page 414-420
Amitava Paul,
Brahma Deo,
Narayanasami Sathyamurthy,
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摘要:
Rate of reduction of iron oxide in iron and steelmaking slags by mass contents of dissolved carbon (>3%) in molten iron depends upon activity of FeO, temperature, mixing of bulk slag and other experimental conditions. A general kinetic model is developed by considering mass transfer of FeO in slag, chemical reaction at gas‐metal interface and chemical reaction at gas‐slag interface, respectively, as the three rate controlling steps. A critical analysis of the experimental data reported in literature has been done. It is shown that in the case of slags containing mass contents of less than 5% FeO, the reduction of FeO is controlled by mass transfer of FeO in slag plus chemical reaction at gas‐metal interface; when slags contain more than 40% FeO, the reduction of FeO is controlled by chemical reaction at gas‐metal interface plus chemical reaction at gas‐slag interface; at intermediate FeO mass contents (between ∼ 5 and 40% FeO), the reduction of FeO is controlled by all three steps, namely, mass transfer of FeO in slag, chemical reaction at gas‐metal interface and chemical reaction at gas‐slag interface. The temperature dependence of rate constant for the gas‐slag reaction is obtained as:Ink2= –32345.4(&6128)/T+ 19.0(&3.42); σlnk2,1/T=&0.3.wherek2is expressed in mol m‐2s‐1bar‐1. The mass transfer coefficient of iron oxide in bulk slag is found to vary in the range 1.5 × 10‐5to 5.0 × 10‐5m/s, depending upon the slag composition as well as experimental conditions.
ISSN:0003-8962
DOI:10.1002/srin.199401186
出版商:Wiley
年代:2016
数据来源: WILEY
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4. |
Thermodynamic activities of FeO in CaO‐FeO‐SiO2slags |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 10,
2016,
Page 421-428
Johan Bygdén,
Du Sichert,
Seshadri Seetharaman,
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摘要:
In the present work, a thermodynamic model to describe the activities of components in complex slag systems based on a Temkin approach has been put forward. The model was applied to the ternary system CaO‐“FeO”‐SiO2in order to calculate the activities of FeO as a function of temperature and composition from literature data. For this purpose, the experimental data on the activity of FeO available in literature were complemented in the present work by ZrO2‐CaO solid electrolyte galvanic cell measurements for some selected compositions. An assessment of the data for the binary systems FeO‐SiO2and CaO‐FeO was carried out. The computed ternary activities are presented in the form of iso‐activity lines at 1673 and 1873K. On the basis of the model predictions, the reliability of the solid electrolyte method for such measurements is discussed.
ISSN:0003-8962
DOI:10.1002/srin.199401187
出版商:Wiley
年代:2016
数据来源: WILEY
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5. |
Remelting of scrap containing tungsten and nickel in the electric arc furnace |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 10,
2016,
Page 429-432
Oleg Ostrovski,
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摘要:
Remelting of the metallic scrap containing tungsten and nickel and thermodynamic properties of slag containing tungsten oxide are discussed. Tungsten and nickel in the metallic scrap have to be separated before the scrap may be used for melting of some steels (for example, high speed steel). To separate tungsten and nickel, such scrap (waste drills) was remelted in the 25 t electric arc furnace under oxidizing conditions. Tungsten was oxidised and transferred to the slag phase, while nickel remained in the metal. Further, the slag containing tungsten oxide was used in the melting of high speed steel. Metal containing nickel was utilized in the constructional steel production. Technology of the scrap remelting was developed on the basis of thermodynamic analysis of slag containing tungsten oxide and tungsten slag‐metal partition. It was found that the coefficient of tungsten distribution between iron and basic CaO‐SiO2‐FetO‐WO3slag increases with increasing slag basicity. In the industrial oxidising heats a slag of high basicity was used, it secured 94% tungsten extraction from scrap to the slag.
ISSN:0003-8962
DOI:10.1002/srin.199401188
出版商:Wiley
年代:2016
数据来源: WILEY
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6. |
Steady state model for current and temperature distributions in an electric smelting furnace |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 10,
2016,
Page 433-437
Eunny Sridhar,
A. K. Lahiri,
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摘要:
A two‐dimensional mathematical model has been developed for predicting current and temperature distributions in an electric smelting furnace. The current distribution is calculated by solving differential equation for magnetic field intensityHθwith A.C. input. Temperature distribution in the furnace is evaluated by solving the equation for conservation of energy. The data used for the model is based on the ferro manganese production. The effect of various operating parameters such as electrode depth, electrical conductivity of the charge and the slag on the power consumption, heat loss, slag and top gas temperatures have been studied in the present model.
ISSN:0003-8962
DOI:10.1002/srin.199401189
出版商:Wiley
年代:2016
数据来源: WILEY
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7. |
Phase transformations and microstructure changes in a 12%Cr‐steel during tempering at 1053 K |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 10,
2016,
Page 438-443
Jozef Janovec,
Barbara Richarz,
Hans Jürgen Grabke,
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摘要:
The evolution of the microstructure and the phase transformations in a 12% Cr‐steel during tempering at 1053 K for 30 s, 0.25, 1 and 2 h were studied. The investigations were carried out by transmission electron microscopy. For the identification of the different phases and the determination of their chemical composition electron diffraction and energy dispersive X‐ray spectroscopy were used. Four different types of precipitates were found: MX, M3C, M2X and M23C6. They showed the following time dependent precipitation sequence: MX → MX + M3C → MX + M2X + M23C6→ MX + M23C6. Changes in the chemical composition of the various precipitates were determined. The chemical composition of the M23C6carbide was nearly constant, whereas it varied with time for the M2X and MX carbonitrides. Two different types of MX particles were identified: Ti,V‐rich precipitates in the quenched and short‐term tempered states and V,Cr‐rich particles in the longer‐term tempered states. Two types of orientation relationships between the ferrrite and the M23C6were observed:and.
ISSN:0003-8962
DOI:10.1002/srin.199401190
出版商:Wiley
年代:2016
数据来源: WILEY
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8. |
Phase transformations during tempering of the Fe‐15Cr‐1Mo martensites containing nitrogen or carbon |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 10,
2016,
Page 444-450
Hans Berns,
Sergej Nikolaijevitsch Bugajchuk,
Vladimir Andrejevitsch Duz,
Rüdiger Ehrhardt,
Valentin Gennadijevitsch Gavriljuk,
Yuri Nikolaljevitsch Petrov,
Igor Arkabijevitsch Yakubzov,
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摘要:
Hardness measurements, dilatometry, internal friction measurements, Mössbauer spectroscopy and transmission electron microscopy are utilized in order to study the effect of tempering on the microstructure of a stainless martensitic steel containing 15% Cr, 1% Mo and 0.6% N. A similar carbon steel containing 15% Cr, 1% Mo and 0.6% C is used for comparison. Tempering of alloy Fe‐15Cr‐1Mo‐0.6N in the low temperature range of 353‐473 K leads to formation of hexagonal ∊‐nitride (Fe,Cr)2N, which is followed by precipitation of the orthorombic ∊‐nitride (Fe,Cr)2N at temperatures of 573‐773 K. The hexagonal nitride Cr2N is precipitated at 923 K and preferably formed at grain boundaries. The alloy Fe‐15Cr‐1Mo‐0.6C shows the expected tempering behaviour. ∊‐carbide (Fe,Cr)2C and cementite (Fe,Cr)3C are precipitated during low temperature ageing, followed by the formation of Cr7C3carbides after the temperature has risen to 873 K. With a similar interstitial content the amount of retained austenite in the nitrogen martensite is nearly twice as high as in the carbon one. Furthermore, the thermal stability of the retained austenite of the nitrogen alloy is substantially higher than that of the carbon steel.
ISSN:0003-8962
DOI:10.1002/srin.199401191
出版商:Wiley
年代:2016
数据来源: WILEY
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9. |
Fatigue behaviour of Ni3Al(B) alloys at room temperature |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 10,
2016,
Page 451-454
Gang Li,
Jian‐Ting Guo,
Zhong‐Guang Wang,
Chang‐Xu Shi,
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摘要:
The high cycle fatigue behaviour of high boron polycrystalline Ni3Al alloys is studied. A single phase Ni3Al alloy with a mole fraction of 0.6% B and a Ni3Al alloy containing a mole fraction of 1.0% B with a small amount of the boride eutectic at the grain boundaries are selected for investigation. High cycle fatigue tests at room temperature with R (minimum stress/maximum stress) 0.1 are conducted in air and at 30 Hz. The results show that the Ni3Al(0.6% B) alloy is better than the Ni3Al(1.0% B) alloy in the fatigue resistance, although, the latter is much higher than the former in static strengths. The fatigue fracture surfaces are observed by SEM.
ISSN:0003-8962
DOI:10.1002/srin.199401192
出版商:Wiley
年代:2016
数据来源: WILEY
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10. |
Evaluation of abrasive‐wear and erosion‐corrosion resistance of high‐Cr cast‐steel |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 10,
2016,
Page 455-458
W. A. Metwally,
M. K. Samy,
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摘要:
In order to evaluate the performance of high‐Cr cast‐steel (15.4% Cr), as a pump casing material, abrasive wear, hardness, corrosion, erosion‐corrosion resistance were examined and compared with grey cast iron eventually used. The results obtained were analyzed on a microstructural basis with respect to Cr content of the matrix, amount and types of carbides and the extent of surface passivation. Martensitic high‐Cr steel has shown a better performance than grey cast iron.
ISSN:0003-8962
DOI:10.1002/srin.199401193
出版商:Wiley
年代:2016
数据来源: WILEY
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