1. |
Solubility of nitrogen in CaO‐SiO2‐CaF2slag system |
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Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 6,
2016,
Page 221-226
Hyo Seok Song,
Peter Chang Hee Rhee,
Dong Joon Min,
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摘要:
Equilibrium experiments between gas and slag were carried out to understand the thermodynamic behaviour of nitrogen in the CaO‐SiO2‐CaF2slag system at 1600°C. The solubility of nitrogen in this slag system increased as the oxygen potential decreased and as the reaction temperature increased. The values of the nitride capacity have a minimum at about 2.0 slag basicity, having higher values in both more acidic and basic regions. This may be explained by two mechanisms for nitrogen dissolution; incorporated nitride ion and free nitride ion state. In slag with 2.0 basicity or less, MgO content increased the nitride capacity slightly. At higher slag basicity, however, nitride capacity decreased with MgO content. The effects of BaO to substitute CaO on nitride capacity showed similar behaviour as MgO. This complex relationship between basicity of slag and nitride capacity is explained by using optical basicity. It was found that nitride capacity and optical basicity had a close relationship even in the different basic oxide systems.
ISSN:0003-8962
DOI:10.1002/srin.199605481
出版商:Wiley
年代:2016
数据来源: WILEY
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2. |
Influence of gases dissolved in cooling water on heat transfer during stable film boiling |
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Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 6,
2016,
Page 227-234
Rudolf Jeschar,
Heiner Kraushaar,
Holger Griebel,
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摘要:
Results of investigations concerning the determination of the influence of the water quality on the heat transfer of quenched hot metal surfaces are presented. With an immersion quenching device, tests have been carried out for various cooling water qualities. Apparently there was no correlation between the water quality and the cooling process (Leidenfrost temperature). High concentrations of dissolved gases yield stable vapour films (low Leidenfrost temperatures are measured). Salt displaces the dissolved gases from the water; the Leidenfrost temperature rises: the higher the salt concentration, the lower the gas concentration and, therefore, the higher the Leidenfrost temperature. If salt concentrations are high or the cooling water is degassed, the vapour film falls apart just after Immersion. An extended model considering the Influence of the gases allows the correlation of the water quality/salt concentration and the heat transfer/Leidenfrost temperature.
ISSN:0003-8962
DOI:10.1002/srin.199605482
出版商:Wiley
年代:2016
数据来源: WILEY
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3. |
Study on buckling of convex fillet welded joint |
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Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 6,
2016,
Page 235-239
Dong Jianling,
Wang Zhaolin,
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摘要:
In the production of spherical vessels by using single‐curvature polyhedron hydrobulging technology, one of the difficulties to be overcome is buckling of a convex fillet welded joint, which can make a polyhedron fracture along the fillet welded joint during hydrobulging, quality of the spherical vessel bulged from the polyhedron bad. In order to find measures to solve the problem, this paper studies the buckling mechanism of a convex fillet welded joint. It shows that the direct reason for buckling is the action of compressive stress along the tangential direction of the convex fillet welded joint, and the height of a buckle increases with the inside pressure of a bulged polyhedron during the bulging process after buckling occurs. Avoiding a convex fillet welded joint forming an enclosed ring or approximately enclosed ring in a section and outside the constant‐area sphere of the polyhedron or increasing dihedral angle of covex fittet welded joints can decrease the compressive stress along the tangential direction of the convex fillet welded joint. So the measures can prevent buckling from occurring or decrease height of a buckle.
ISSN:0003-8962
DOI:10.1002/srin.199605483
出版商:Wiley
年代:2016
数据来源: WILEY
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4. |
Effects of tramp elements Cu, P, Pb, Sb and Sn on the kinetics of carburization of case hardening steels |
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Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 6,
2016,
Page 240-246
Andreas Ruck,
Daniel Monceau,
Hans Jürgen Grabke,
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摘要:
Investigations on the effect of tramp elements and impurities on the gas carburization of case hardening steels in CO‐H2‐H2O gas mixtures at 930°C in a flow apparatus by thermogravimetric experiments were carried out. The influence of surface segregation on the kinetics of the surface reaction and the influence of decreasing carbon transfer coefficientßon the carbon concentration profile were estimated. Numerical calculations were developed to determine the carbon transfer coefficientß.
ISSN:0003-8962
DOI:10.1002/srin.199605484
出版商:Wiley
年代:2016
数据来源: WILEY
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5. |
Validation of thermal‐kinetic‐diffusion model for arc plasma surface hardening of steel |
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Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 6,
2016,
Page 247-252
Michail Kryzhanovski,
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摘要:
Realistic analysis of the surface hardening pocesses during an arc plasma torch application indicates that the events taking place during a plasma torch pass should be properly looked at as a thermal‐kinetic‐diffusion problem. Arbitrary separation of these components may lead to erroneous evaluation of the variables and parameters that characterise the process. Consequently, a complex finite element model, which describes elementary processes of gas‐solid surface interaction by the method of molecular gas dynamics, connects the transfer processes between gaseous and solid phases and takes into consideration thermal and diffusion events in the steel, has been developed. The adequacy of the mathematical model was substantiated by comparing model predictions to measurements made during surface hardening using an arc nitrogen plasma torch. It was proved that the approach gives the possibility to compute with sufficient accuracy the transient distributions of temperature and concentration fields in the steel surface layer during surface hardening using high‐enthalpy gas flux.
ISSN:0003-8962
DOI:10.1002/srin.199605485
出版商:Wiley
年代:2016
数据来源: WILEY
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6. |
Determination of stacking fault energy of austenite in a duplex stainless steel |
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Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 6,
2016,
Page 253-256
Wolfgang Reick,
Michael Pohl,
Angelo Fernando Padilha,
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摘要:
A determination of stacking fault energy (SFE) of the austenite phase of a duplex stainless steel, material no. 1.4462, has been carried out using transmission electron microscopy (TEM). Furthermore, cold rolling tests and microstructural analysis have been realized in order to allow a detailed discussion of the obtained SFE‐values. The results of this Investigation indicate that the stacking fault energy of the austenite phase within the duplex stainless steel Is lower than those of single‐phase austenitic stainless steels. This is justified by the chemical composition; mainly by the Cr and Ni alloying contents. Nevertheless, work hardening of the austenite during cold deformation is not as accentuated as expected by the low SFE‐values, because at higher deformation levels the deformation mainly occurs within the ferrite phase.
ISSN:0003-8962
DOI:10.1002/srin.199605486
出版商:Wiley
年代:2016
数据来源: WILEY
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7. |
Influence of microalloy type and content on induced precipitation kinetics in microalloyed steels |
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Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 6,
2016,
Page 257-262
Sebastián F. Medina,
Alberto Quispe,
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摘要:
Using torsion tests, and applying the back extrapolation method, the statically recrystallized fraction has been determined for low carbon microalloyed steels with different V, Nb and Ti contents, at different temperatures and an equivalent strain of 0.20%. At temperatures below the static recrystallization critical temperature (SRCT), or the temperature at which strain induced precipitation commences, recrystallized fraction against time curves show a plateau caused by precipitations. The formation of the plateau makes it possible to evaluate precipitation‐time‐temperature (PTT) diagrams, and thus to know the precipitation kinetics. The PTT diagrams show that an increase in the microalloy content raises SRCT and reduces incubation time. For similar Nb, V and Ti contents, Nb is the element which raises SRCT the most.
ISSN:0003-8962
DOI:10.1002/srin.199605487
出版商:Wiley
年代:2016
数据来源: WILEY
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