Ingenieurwissenschaften und zugeordnete Tätigkeiten
Filtern
Erscheinungsjahr
Dokumenttyp
- Vortrag (87)
- Posterpräsentation (36)
- Beitrag zu einem Tagungsband (30)
- Zeitschriftenartikel (13)
- Sonstiges (13)
- Buchkapitel (1)
- Dissertation (1)
Sprache
- Englisch (167)
- Deutsch (12)
- Italienisch (1)
- Mehrsprachig (1)
Referierte Publikation
- nein (181) (entfernen)
Schlagworte
- Corrosion (181) (entfernen)
Organisationseinheit der BAM
- 7 Bauwerkssicherheit (87)
- 7.6 Korrosion und Korrosionsschutz (87)
- 5 Werkstofftechnik (40)
- 5.1 Mikrostruktur Design und Degradation (37)
- 6 Materialchemie (26)
- 6.2 Material- und Oberflächentechnologien (22)
- 4 Material und Umwelt (16)
- 4.1 Biologische Materialschädigung und Referenzorganismen (15)
- 5.0 Abteilungsleitung und andere (3)
- 6.3 Strukturanalytik (3)
- 9 Komponentensicherheit (3)
- 9.0 Abteilungsleitung und andere (3)
- 3 Gefahrgutumschließungen; Energiespeicher (2)
- 3.2 Gefahrguttanks und Unfallmechanik (2)
- 5.6 Glas (2)
- 1 Analytische Chemie; Referenzmaterialien (1)
- 1.4 Prozessanalytik (1)
- 4.2 Material-Mikrobiom Wechselwirkungen (1)
- 4.5 Kunst- und Kulturgutanalyse (1)
- 5.4 Multimateriale Fertigungsprozesse (1)
- 6.0 Abteilungsleitung und andere (1)
- 6.7 Materialsynthese und Design (1)
- 7.4 Baustofftechnologie (1)
- 9.2 Versuchsanlagen und Prüftechnik (1)
Eingeladener Vortrag
- nein (87)
Meteorites are a unique and inspiring material for microstructural studies because if their very specific genesis. Iron meteorites have been formed under unimaginable cooling rates of a few ten Kelvins per million years so that the observable transformation of the formerly huge Fe-Ni single crystals of taenite occurred under nearly-equilibrium conditions. Octahedrites (meteorites having a Ni content between 6...15%) are characterized by ribbons of the low-temperature Fe-Ni phase kamacite separated by rims of residual taenite. This very specific feature is known as Widmanstaetten structure and has been investigated by synchrotron radiation in order to cover a higher volume fraction for a statistically relevant description of orientation relationships. However, plessite – a microstructure mainly consisting of the same phases – reflects the orientation relationship between kamacite and taenite as well. For their characterization, a scanning electron microscope is very suitable in order to investigate crystal orientations or identify phases. Despite the apparently ideal formation circumstances of iron meteorites, Ni concentration profiles prove non-equilibrium conditions. Combined EDS (energy dispersive spectroscopy) and EBSD (electron backscatter diffraction) measurements at a selected plessitic region of the Cape York iron shows that a correlation exists between Ni-concentration and the locally detected orientation relationship.
Combining CO2 Streams from Different Emitters – A Challenge For Transport And Storage Infrastructure
(2015)
The European Directive 2009/31/EC on the geological storage of CO2 envisages an open access of CO2 streams from different emitters to a nation- or even EUwide CO2 pipeline network if CO2 stream compositions meet “reasonable minimum composition thresholds”. As of today it is not known how such “composition thresholds” may be defined and which impurity levels may be viable in practical application.
To set up recommendations for criteria and respective threshold values for CO2 stream compositions, the project “CLUSTER” will investigate how a dynamic interplay – both in terms of mass fluxes and compositions – of CO2 streams from regionally clustered CO2 sources sharing a transport and storage infrastructure will impact corrosion, e.g., of pipelines and plant components, and geochemical alteration of cap rocks and reservoir rocks. In addition, the behaviour of such a highly dynamic CCS system will be considered for an overall optimization of system design including CO2 stream mixing schemes and facilities or interim CO2 storage.
Ferritic-martensitic high temperature alloys are used as building components for different power plant technologies. Depending on the type of fuel, the used power plant materials are exposed to different temperatures and reactive atmospheres containing e.g. CO2, O2, or SO2. Despite the sulfur chemistry is commonly present as an impurity in fossil or bio fuels; its role in high temperature corrosion is not entirely understood. During high temperature corrosion, high-alloyed steels often show sulfur precipitates with the ignoble alloy component(s) along grain boundaries within the base material. Sulfur precipitates are known to seriously influence the mechanical properties of the building component. In the case of VM12 and T92 steels, sulfur phases penetrate the base material along grain boundaries during the corrosion under oxyfuel atmosphere up to 20 µm within the first 960h (Fig. 1a). Figure 1a shows the oxide scale and (Cr, Mn, Fe)xSy grain boundary precipitates in the base material for a T92 steel aged for 960h under oxyfuel atmosphere. Figure 1b shows a thin oxide scale with nodules and also sulfur precipitates of (Fe, Cr)xSy along grain boundaries of the base material for a Fe13Cr model alloy aged for 24h under SO2 atmospheres. After 24h, sulfur precipitates already reached a depth of ca. 15 µm.
The present work shows the corrosion behavior of Fe-Cr model alloys with Cr-contents similar to technical steels up to 13 wt%, aged under oxyfuel (27H2O/60CO2/1SO2/10N2/2O2) and SO2 atmospheres in the temperature range of 550 °C < T < 700 °C and for different time scales between 24 h < t < 960 h. During aging, the reactive gases were added when the experimental temperature was reached. To focus on the reaction of the intended elements Fe, Cr, S, and O, model alloys of high purity are used. Transport depths of sulfur and the nucleation of the precipitates are discussed for both, model alloys and technical steels.
Manganese alloyed stainless steels represent a cost-effective alternative to conventional CrNi- stainless steels due to strong fl uctuations of the market prices for nickel seen during the last years. In CrMnNi steels, nickel is partially replaced by lower-cost manganese and small amounts of nitrogen for stabilization of the austenitic phase. This also brings benefi ts regarding the mechanical properties, as it results in an increased material strength. Laser beam welding of such materials was investigated for direct comparison with Standard CrNi steels. Main emphasis was laid on fi nding adequate process parameters to achieve a stable welding process and obtain a good weld quality. Two different laser sources, a 4.4 kW Nd:YAG and a 5 kW CO2 laser, were used to weld 1.5 mm stainless steel sheets in continuous wave mode. A high-Mn austenitic (1.4376) and a lean duplex (1.4162) steel, as well as the standard austenitic (1.4301) and duplex (1.4362) grades were selected as test materials. Both butt and lap joint confi gurations were studied. Experiments were carried out systematically, varying the welding speed, laser power and focal point position in order to determine adequate process windows. The infl uence of the shielding gas type and fl ow rate on the process stability and the weld quality were investigated. The effects of weld edge preparation on the weld appearance and quality levels attained were also examined. The obtained welded joints were subjected to radiographic tests for detection of internal imperfections. Also a metallurgical characterization of the samples regarding the resulting phase composition or balance and hardness depending on the welding process parameters was conducted. Furthermore, tensile and potentiodynamic tests were performed to evaluate the mechanical and corrosion properties, respectively. The results provide an insight into the advantages and limitations of the laser beam welding process for joining high-manganese alloyed stainless steels. Conditions for the production of defect-free and corrosion-resistant welds having good mechanical properties could be determined.
Properties of pipe steels for CCS (carbon capture and storage) technology require resistance against the corrosive environment of a potential CCS-site (heat, pressure, salinity of the aquifer, CO2-partial pressure). The influence of austenitzing in heat treatment routines of two different injection pipe Steels (1.4034, X46Cr13 and 1.4021, X20Cr13) was evaluated. Steel coupons were austenitized at different temperatures (900- 1050 °C) for different lengths of time (30-90 min) before quenching and annealing prior to long term corrosion experiments (60°C, 100 bar, artificial brine close to a CCS-site in the Northern German Basin, Germany). In general, fewer pits are found on X46Cr13. Comparing steels with 13% chromium each the higher carbon content of X46Cr13 (0.46% C) results in a lower number of pits compared to X20Cr13 (0.20% C). It is found that neither the carbon content of the steels nor austenitizing temperature has much influence, but local corrosion behaviour is most susceptible towards austenitzing time.
Properties of pipe steels for CCS (carbon capture and storage) technology require resistance against the corrosive environment of a potential CCS-site (heat, pressure, salinity of the aquifer, CO2-partial pressure). The influence of austenitzing in heat treatment routines of two different injection pipe steels (1.4034, X46Cr13 and 1.4021, X20Cr13) was evaluated. Steel coupons were austenitized at different temperatures (900-1050 °C) for different lengths of time (30-90 min) before quenching and annealing prior to long term corrosion experiments (60°C, 100 bar, artificial brine close to a CCS-site in the Northern German Basin, Germany). In general, fewer pits are found on X46Cr13. Comparing steels with 13% chromium each the higher carbon content of X46Cr13 (0.46% C) results in a lower number of pits compared to X20Cr13 (0.20% C). It is found that neither the carbon content of the steels nor austenitizing temperature has much influence, but local corrosion behaviour is most susceptible towards austenitzing time.
Similar to the success story of digital photography a major upheaval has been observed in digital industrial radiology. This paper is split into 3 parts:
Part 1: Film Replacement and Backscatter Imaging: Computed radiography with phosphor imaging plates substitutes film applications. Digital Detector Arrays enable an extraordinary increase of contrast sensitivity in comparison to film radiography. The increased sensitivity of digital detectors enables the efficient usage for dimensional measurements and functionality tests substituting manual maintenance. The digital measurement of wall thickness and corrosion status is state of the art in petrochemical industry. Photon counting and energy discriminating detectors are applied up to 300 Kv provide increased thickness dynamic and material discrimination by synchronously acquisition of images of the high and low energy part of the spectrum. X-ray back scatter techniques have been applied in safety and security relevant applications with single sided access of source and detector. First inspections of CFRP in aerospace industry were successfully conducted with newly designed back scatter cameras. Numeric modeling is used to design X-Ray optics and inspection scenarios as well as conducting RT training.
Part 2: Computed tomography (CT)
Part 3: Micro Radiography and Micro CT.
One of the alternative renewable fuels is biomass but it is a difficult fuel because of its diversity and complexity. It can contain high percentages of K and Cl responsible for corrosion together with sand that have additionally an abrasive effect during combustion. Because of permanently extending the surface reaction due to abrasion the corrosion of the materials increases. In particular in power plants, the superheater tubes are exposed to a corrosive abrasive attack that is one of the main sources of concern. The development of new alloys for multilayer surface, which combines corrosive and abrasive resistance is therefore of high importance. Those new technical approaches must be at the same time cost-effective to be an alternative to conventional materials. The aim of the presented investigation methods is to test and develop suitable alloys for coatings for the super heater tubes of biomass power plants. First results of abrasion investigations show improved abrasion resistance compared to the multi-component reference material Alloy 625.