1. |
Simulation of gas dispersion in a metallurgical bubble reactor |
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Archiv für das Eisenhüttenwesen,
Volume 64,
Issue 12,
2016,
Page 581-587
K. Tayfun Erkeskin,
Hans Adolf Friedrichs,
Winfried Dahl,
Klaus W. Lange,
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摘要:
A better understanding of complex process phenomena and engineering of gas dispersion techniques in metallurgical processes can be obtained with the method of computer aided process simulation. Main target of this investigation is to analyze the influence of operational and design parameters such as gas flow rate, reactor diameter, liquid height, or injector size, number and location on the system quantities like mixing power, hold up or degassing rates.The bath aspect ratio should be between 0.8 and 1.2 if the desorption at the bath surface is playing an important role. An optimization of the injected gas quantitiy can be achieved with increased injector cross‐section area (bigger bubbles ascending faster and increasing the mixing power) or higher aspect ratios (longer bubble residence times in the reactor). Dead zones can be avoided by distribution of gas through several injectors positioned symmetrically, increasing total mixing power and specific interface area in the system.
ISSN:0003-8962
DOI:10.1002/srin.199301575
出版商:Wiley
年代:2016
数据来源: WILEY
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2. |
A model of post‐combustion in iron‐bath reactors, part 4: results for post‐combustion with preheated air |
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Archiv für das Eisenhüttenwesen,
Volume 64,
Issue 12,
2016,
Page 588-596
Liuyi Zhang,
Franz Oeters,
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摘要:
This paper describes calculated results of post‐combustion with pre‐heated air, heat transfer from gas to the melt via a mixture of metal and slag droplets, reoxidation at the metal droplets, CO evolution rate from the melt, production rate of the reactor, and carbon consumption of various process modes of a 15‐t reactor with or without oxygen blowing through the vessel bottom. Using pre‐heated air, the achievable post‐combustion degree is higher than using pure oxygen. Nevertheless, slag droplets as heat carrier are necessary. With 50 % slag droplets the real post‐combustion degree can be higher than 45 %. With 90 % slag droplets it can be even higher than 80 %. The operating point of the reactor is discussed.
ISSN:0003-8962
DOI:10.1002/srin.199301576
出版商:Wiley
年代:2016
数据来源: WILEY
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3. |
Evaluation of deterioration mechanisms and roll life of different roll materials |
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Archiv für das Eisenhüttenwesen,
Volume 64,
Issue 12,
2016,
Page 597-603
Sven‐Erik Lundberg,
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摘要:
Evaluation of wear loss of rolls in operation is very difficult since the rolling conditions are hard to keep under control. To solve this problem a high temperature test rig was designed. A conventional roll material was compared to a hot work tool steel. The main wear mechanisms were different. The conventional roll grade was mainly subjected to thermal fatigue as could be expected. The hot work tool steel was mainly subjected to abrasive wear, and no evidence of thermal fatigue was found. The rate of material loss was 6 times higher in the hot work tool steel, but when the deterioration caused by thermal fatigue of the cast iron is taken into consideration, the deterioration rate was of the same order in both materials. The friction between the hot steel and the roll materials were of the same order. The frictional value should be a measure of the wear rate. Since the wear mechanisms are not equal, the coefficient of friction found in the test rig is only qualitatively related to roll wear.
ISSN:0003-8962
DOI:10.1002/srin.199301577
出版商:Wiley
年代:2016
数据来源: WILEY
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4. |
Simulation of the temperature field along the cross‐section of a ring during the ring rolling process |
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Archiv für das Eisenhüttenwesen,
Volume 64,
Issue 12,
2016,
Page 604-610
Kevin E. Sweeney,
Achim Kluge,
Herbert Wiegels,
Reiner Kopp,
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摘要:
This paper presents the approach used to simulate the temperature distribution/progression of a ring with a rectangular cross‐section during the ring rolling process. The previously existing 2‐D FEM program Finel was used and modifications were made to consider the metal flow in the out‐of‐plane direction. Simulations were performed for the austenitic steel X6CrNiNb18‐10 and the aluminium alloy AA‐2219. Each simulation was a combination of multiple, alternating thermal/mechanical and thermal calculations, representing the time the cross‐section is in the roll gap and the time it is between the roll gaps. The results from the simulation were compared to preliminary measured values.
ISSN:0003-8962
DOI:10.1002/srin.199301578
出版商:Wiley
年代:2016
数据来源: WILEY
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5. |
Hot stress‐strain curves of steel determined by different kinds of deformation |
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Archiv für das Eisenhüttenwesen,
Volume 64,
Issue 12,
2016,
Page 611-617
Radko Kaspar,
Peter Michael Müller,
Franz‐Dieter Philipp,
Günter Backmann,
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摘要:
For the modelling of microstructure development during hot deformation operations as well as for the prediction of deformation loads stress‐strain data are required. For this purpose various laboratory deformation techniques are employed. On two steel grades (medium carbon Cr‐Mo steel and austenitic Cr‐Ni steel) axisymmetric and plane strain compression tests as well as torsion tests were applied with the aim of comparing equivalent stress‐strain curves determined by such different deformation tests. The results showed that for the calculations of deformation loads during multi‐deformation industrial operations with rather small individual deformation steps, the choice of laboratory deformation test is not a critical point. Nevertheless, conflicting results are expected by an exact interpretation of stress‐strain curves concerning microstructural development by using different testing methods.
ISSN:0003-8962
DOI:10.1002/srin.199301579
出版商:Wiley
年代:2016
数据来源: WILEY
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6. |
Thermodynamic calculation and precipitation of carbides in the Fe‐Cr‐Ni‐C system |
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Archiv für das Eisenhüttenwesen,
Volume 64,
Issue 12,
2016,
Page 618-622
Caian Qiu,
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摘要:
A series of calculated isothermal and vertical sections of the Fe‐Cr‐Ni‐C phase diagrams have been presented, and some of them are compared with experimental observations available. These diagrams can provide an important basis for heat treatments and for further developments of stainless steels. Effects of the alloying elements on the phase relations and on the precipitation of the Cr‐rich carbide (M23C6) have been examined by means of thermodynamic calculation. After introducing proper assumptions, the critical condition for M23C6precipitation from the austenite were calculated from the thermodynamic properties of the Fe‐Cr‐Ni‐C system, and such conditions predict the loss of corrosion resistance of austenitic stainless steels.
ISSN:0003-8962
DOI:10.1002/srin.199301580
出版商:Wiley
年代:2016
数据来源: WILEY
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7. |
Kinetics of ferrite transformation in an HSLA steel containing Nb |
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Archiv für das Eisenhüttenwesen,
Volume 64,
Issue 12,
2016,
Page 623-629
Shant P. Gupta,
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摘要:
An investigation was carried out to study the thickening kinetics of ferrite allotriomorph in a high‐strength low‐alloy (HSLA) steel containing Nb. Using optical microscopy to measure growth distance, it has been shown that the movement of the α/γ interface follows a parabolic relationship with the reaction time. By modelling the steel as a ternary Fe‐C‐Mn alloy, the growth rate constants, αe and αpara, were calculated assuming full equilibrium and paraequilibrium modes of transformation, respectively. The parabolic growth rate constant lies within an order of magnitude of the values for αpara up to about 1000 K with no partitioning of Mn. An abrupt decrease in the rate of growth of ferrite has been observed at higher temperatures. The parabolic growth rate constant at the highest temperature (1062 K) is about an order of magnitude higher than the value of αe indicating that equilibrium partitioning of Mn has occurred. Thus a change from no partitioning at lower temperatures to partial or full partitioning of Mn at higher temperatures describes the kinetics of ferrite transformation in this steel.
ISSN:0003-8962
DOI:10.1002/srin.199301581
出版商:Wiley
年代:2016
数据来源: WILEY
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8. |
News from the Max‐Planck‐Institut für Eisenforschung GmbH |
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Archiv für das Eisenhüttenwesen,
Volume 64,
Issue 12,
2016,
Page 630-632
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ISSN:0003-8962
DOI:10.1002/srin.199301582
出版商:Wiley
年代:2016
数据来源: WILEY
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