1. |
Laudation in honour of Professor Dr.‐Ing. Hans Paul Hougardy on the occasion of his 65th birthday |
|
Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 10,
2016,
Page 395-396
Winfried Dahl,
Preview
|
PDF (218KB)
|
|
ISSN:0003-8962
DOI:10.1002/srin.199605508
出版商:Wiley
年代:2016
数据来源: WILEY
|
2. |
Subcommittee for metallography, analysis and simulation of materials at the VDEh |
|
Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 10,
2016,
Page 397-400
Hans‐Joachim Wieland,
Preview
|
PDF (463KB)
|
|
ISSN:0003-8962
DOI:10.1002/srin.199605509
出版商:Wiley
年代:2016
数据来源: WILEY
|
3. |
Simulation of diffusion controlled phase transformations in steels |
|
Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 10,
2016,
Page 401-407
Gerhard Inden,
Peter Neumann,
Preview
|
PDF (858KB)
|
|
摘要:
Phase transformations in steels are currently treated with empirical approaches which make use of the vast amount of existing knowledge and experience. The aim of this paper is to show that more fundamental approaches are complementary, and mandatory in order to arrive at predictive capabilities. Such approaches have to take into account the local conditions on a microscopic level such as inhomogeneities, element distributions, driving forces, thermodynamic properties of the phases. With this sophistication it becomes possible to treat complex situations such as the long term stability of microstructures under service conditions, giving room for new optimizations.
ISSN:0003-8962
DOI:10.1002/srin.199605510
出版商:Wiley
年代:2016
数据来源: WILEY
|
4. |
Transformation of austenite into bainitic ferrite and martensite |
|
Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 10,
2016,
Page 408-411
Hermann Vetters,
Preview
|
PDF (492KB)
|
|
摘要:
The stress induced martensitic transformation in the upper metastable intermediate state of γ‐α transformation in ferrous materials, structured as ferritic bainite, is discussed. The fibrous structured ferritic bainite consists of retained austenite and ferrite platelets growing in the [111]α//[101]γ direction. The ferrite growth Induces carbon enrichment of the adjacent austenite at the phase boundaries. Strengthening at high stress levels up to the yield point causes dislocation tangles in the ferrite fibre and the formation of shear bands crossing each other in the retained austenite. At lower carbon contents of the austenite, lath martensite precipitates at the shear band intersections and at high shear band densities martensite blocks are observed. In carbon enriched austenite martensite lenses formed by shear processes have been observed. At alternating loading conditions, exceeding the stress level for athermic martensite formation, various shear planes are activated forming characteristic patterns of plate martensite.
ISSN:0003-8962
DOI:10.1002/srin.199605511
出版商:Wiley
年代:2016
数据来源: WILEY
|
5. |
Changes in transformation behaviour and microstructure of a CrV‐spring steel by thermomechanical treatment |
|
Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 10,
2016,
Page 412-418
Andreas Peters,
Radko Kaspar,
Oskar Pawelski,
Preview
|
PDF (772KB)
|
|
摘要:
The effect of austenite deformation on the transformation behaviour was investigated on a CrV‐spring steel with the major attention put on the martensitic transformation. In the first part, a small review is given on the relation between the state of austenite after hot deformation and its influence on the formation of martensite. In the laboratory tests, the second part of the paper, a conventional heat treatment (CHT) was compared with two types of austenite conditioning by thermomechanical treatment (TMT): TMTR‐ with deformation above the recrystallization temperature ϑRleading to a fully recrystallized austenite and TMTN‐ with deformation below ϑRwith a not recrystallized but possibly polygonized austenite. For the laboratory tests, the hot deformation simulator Wumsi was employed. After quenching In oil, the martensite after TMT consisted of associations of many fine fragments with a smaller number of large acicular martensitic units than observed after CHT. In both TMT‐variants small ferritic areas (<1 μ m) could be revealed. Different behaviour of martensite during tempering at low temperatures was observed after CHT and TMT. It can be explained by reduced inherent stresses generated during martensitic transformation after TMT, presumably as a result of a better ability of deformed austenite to withstand the accommodation strain during martensitic transformation. This may have considerable consequences for the toughness properties of tempered martensite.
ISSN:0003-8962
DOI:10.1002/srin.199605512
出版商:Wiley
年代:2016
数据来源: WILEY
|
6. |
Spatial distribution of Fe3C‐particles in steel during coarsening |
|
Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 10,
2016,
Page 419-422
Kurt Wiencek,
Preview
|
PDF (438KB)
|
|
摘要:
The particles’ arrangement of disperse phases can be described by the space distribution of particle centers as well as by relations between center positions and particle sizes. By means of the sphere models of known stochastic properties one can obtain some information on the particle arrangement by stereology. The models make it possible to determine (by calculation or simulation) functions which characterise the distribution of the centers of two‐dimensional particles In planar sections, i.e., the pair‐coorrelation function and the nearest neighbour distance distribution, and compare them with respective empirical functions. The steorological analysis of the two disperse systems of Fe3C‐particles in steel observed during the different stages of the coarsening process indicate that these dispersions follow the Stienen model (a model for non‐overlapping spheres), i.e., the particle centers form a Poisson point field while the particle sizes are dependent on and determined by the nearest neighbours distance of the particle centers.
ISSN:0003-8962
DOI:10.1002/srin.199605513
出版商:Wiley
年代:2016
数据来源: WILEY
|
7. |
Determination and assessment of homogeneous microstresses in polycrystalline materials |
|
Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 10,
2016,
Page 423-429
Herfried Behnlten,
Vildor Hauk,
Preview
|
PDF (660KB)
|
|
摘要:
Microstresses due to different origins and tfieir spacial distributions are of increasing interest for tiie description of material properties and mechanical behaviour. They cause broadenings as well as shifts of the X‐ray interference lines, and by this they can be classified into inhomogeneous and homogeneous microstresses. The latter are discussed in this paper. The definitions of the different kinds of microstresses are described. The possibilities of microstress determination and separation are outlined and illustrated with examples. A short review Is given on the assessment of homogeneous microstresses with respect to their stability during cyclic loading and their influence on the loading capacity.
ISSN:0003-8962
DOI:10.1002/srin.199605514
出版商:Wiley
年代:2016
数据来源: WILEY
|
8. |
Microalloyed, vacuum degassed high‐strength steels with special emphasis on IF steels |
|
Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 10,
2016,
Page 430-437
Bernhard Engl,
Thomas Gerber,
Preview
|
PDF (931KB)
|
|
摘要:
In comparison with other high‐strength concepts, high‐strength IF steel has a particularly high forming capacity with increased strength, while the sheet thickness reduction through forming is, on the whole, smallest with high‐strength IF steel. Solid‐solution hardening through Si, Mn and P is particularly suitable as a mechanism for increasing strength, as this leads to comparatively low formability losses with increased strength values. An additional increase in strength is possible using the bake‐hardening effect. This can be achieved with an incomplete C and N binding through Ti and/or Nb, or through stoichiometric microalloying with V. The effect is basically caused by the relatively low thermodynamic stability of VC. V‐alloyed, vacuum degassed steel combines in this way good forming behaviour with an increase in strength through bake‐hardening.Through an increasing segregation of P at grain boundaries, solid solution hardening with this element can lead to unfavourable embrittlement in higher strength IF steel and to intercrystalline fracture. B‐addition to the amount of 0.002% (mass content) greatly reduces the tendency to become brittle without leading to any remarkable losses with regard to formability. Examinations concerning the precipitation behaviour of Ti‐IF steel with P show that a formation of iron titanium phosphate (FeTiP) in the hot strip only occurs where there is an excess of Ti and high coiling temperatures are used. For a P‐alloyed IF steel with stoichlometrical Ti‐content no precipitation of FeTiP takes place in hot band, nor is the thermal activation in continuous annealing simulation sufficient to achieve a transformation of existing Ti‐precipitates into FeTiP, which might occur according to literature.
ISSN:0003-8962
DOI:10.1002/srin.199605515
出版商:Wiley
年代:2016
数据来源: WILEY
|
9. |
Toughness requirements for steel structural components with surface flaws |
|
Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 10,
2016,
Page 438-443
Fabian Grimpe,
Winfried Dahl,
Wolfgang Bleck,
Preview
|
PDF (603KB)
|
|
摘要:
Fracture mechanic safety analyses consist of a comparison between material toughness and toughness requirement of the Investigated structure. For the selection of suitable materials the requirements must be known. The fracture mechanics toughness requirements for a structural component depend on several parameters. Load case, geometry of the component and of a postulated or detected flaw, strength of the steel and the chosen safety criterion are decisive for the toughness requirements. Performing three‐dimensional elastic plastic finite element analyses the toughness requirements for plates of high strength structural steels with surface flaws have been determined as a function of the above mentioned parameters.
ISSN:0003-8962
DOI:10.1002/srin.199605516
出版商:Wiley
年代:2016
数据来源: WILEY
|
10. |
High strain rate superplasticity in the fine‐grained duplex stainless steel Fe‐22Cr‐5Ni‐3Mo‐0.3N |
|
Archiv für das Eisenhüttenwesen,
Volume 67,
Issue 10,
2016,
Page 444-449
David Hernandez,
Georg Frommeyer,
Harald Hofmann,
Preview
|
PDF (708KB)
|
|
摘要:
The fine‐grained duplex stainless steel Fe‐22Cr‐5Ni‐3Mo‐0.3N consisting of α‐ and γ‐Fe(Cr,Ni,Mo) solid solutions exhibits structural superplasticity at deformation temperatures of 900 to 1050°C. The equiaxed microstructure with an average grain size ofdα,γ≈ 3 μm was produced by thermomechanical processing. This steel shows also superior superplastic properties at high strain rates up to ε ≈ 5 · 10−2s−1. Maximum strain rate exponents ofm≈ 0.5 and elongations to failure of more than 800% were achieved. The superplastic deformability (m>0.3) of this steel in a wide strain rate range enables near net shape deep drawing or blow forming of parts with complex shape applying low flow stresses.A deformation model is presented to describe the superplastic behaviour at high strain rates. Grain and interphase boundary sliding is accommodated by sequential steps of dislocation glide and climb. The maximumm‐value of about 0.5 and an activation energy of 260 kJ/mol, which is comparable to that of self diffusion of Iron in γ‐Fe (270 kJ/mol), and high dislocation densities indicate that dislocation climb in the slightly solid solution hardened γ‐Fe phase (solid solution class II type of material) is the rate controlling step for superplastic flow.
ISSN:0003-8962
DOI:10.1002/srin.199605517
出版商:Wiley
年代:2016
数据来源: WILEY
|