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Organisationseinheit der BAM
- 7.6 Korrosion und Korrosionsschutz (354) (entfernen)
In the late 1980s, a new type of corrosion appeared in drinking water installations where galvanized steel pipes failed forming a deep groove with no corrosion at the other surfaces. The reason was discussed quite fiercely between failure analysts and material suppliers. In the end the discussion lead to the solution: inductive welded pipes of a certain sulphur content were prone to selective corrosion. The history of the arguments is discussed using old communications between Wilhelm Schwenk and Wolfgang Stichel, who later published the results in a paper unfortunately only I german.
Thus the knowledge got lost and new cases based on the same material problems are observed in application of so-called C-Steel piping systems. Failure cases are shown.
The screening of coatings shows that the modification by adding individual pigment was not sufficient to protect carbon steel even during a short-term exposure, indicated by the discoloration after only seven days of exposure.
Electrochemical tests indicated that the coating cathodically protects carbon steel or slows down the corrosion reaction.
A long-term exposure test confirmed that the PANI/SiO2 modified coating successfully protects the carbon steel in the Sibayak artificial geothermal water at 150 °C for 6 months.
Corrosive geothermal brines are a major challenge to geothermal power-plants. For cost reasons, plant designers favorize low alloyed steels, e.g., carbon steel, which are susceptible to uniform and localized corrosion when exposed to geothermal brines having acidic and saline properties. To solve such problem, coatings or inhibitors would be a protective solution as an alternative to the use of high alloyed materials.
This study investigated a coating system consisting of polyaniline/silicon dioxide basing on locally available resources. Protection against corrosion of carbon steel is shown by long-term exposure and electrochemical tests of coated carbon steels, performed in an artificial acidic and saline geothermal brine, comparable to real conditions at a site in Indonesia.
Therefore, an integrated coating system is presented for corrosion protection, combining the electro-chemical functionality of polyaniline and the physical advantages of silica.
Nachdem im Verbundprojekt COORAL das Hauptaugenmerk auf überkritisches CO2 gelegt wurde, d. h. Transport über kurze Strecken bei erhöhter Temperatur, wurde in CLUSTER ein größeres lokales Transport-Netzwerk betrachtet, bei dem CO2 bei geringeren Temperaturen, also vorwiegend im flüssigen Zustand transportiert wird. Wurden in COORAL die CO2-Ströme von Kohlekraftwerken untersucht, ging es in CLUSTER zusätzlich um die Emissionen von relevanten Industrien, deren CO2-Emissionen nicht ohne Weiteres vermieden werden können.
Aufgrund der Erfahrungen in COORAL konnte eine Auswahl von kommerziellen Werkstoffen getroffen werden, die für einen konkreten Einsatz für CCS zur Verfügung stünden. Die gemischten und fluktuierenden CO2-Zusammensetzungen sind bei geeigneten Begrenzungen der Begleit¬stoffe im CO2 bezüglich Korrosionsvorgänge beherrschbar. Die Machbarkeit eines lokalen CCS-Clusters erscheint daher gegeben, soweit dies die Anlagen für Kompression, Transport und Injektion betrifft.
CCS technology - Carbon Dioxide Capture and Storage, has been recognized as an excellent technology to reach the target of CO2 reduction. However, the safety issue and cost effectiveness currently hinder the future of CCS. Recent studies have shown that even at a very low concentration of impurities (less than 100 ppmV of SO2, NO2, O2 and H2O) the droplet formation and condensation of sulfuric and nitric acids in dense phase CO2 are possible and observable [1-3].To reveal the mechanism of droplet corrosion in dense CO2 at high pressure and low temperature, further studies on factors that affect wettability and resulting corrosion behaviors of transport pipeline steels are needed.
In this work, carbon steel 1.8977 (L485MB), CrMo-alloyed steel 1.7225 (42CrMo4), martensitic steel 1.4313, and superaustenite steel 1.4562 (alloy 31) were investigated. The wettability was determined by contact angle measurement of sessile drop in CO2 atmosphere, at different pressure and temperature. The corrosion behavior of steels was investigated with standard exposure tests, followed by mass loss determination, surface characterization by scanning electron microscope (SEM) and chemical analysis by Energy Dispersive X-Ray Analysis (EDX). Exposure tests with and without the synthetic CO2 saturated water droplets were performed at both low temperature (278 K) and higher temperatures (288 K and 313 K) at high pressure where CO2 is supercritical or in dense phase. The investigated flue gases were SO2 (70-220 ppmV) and O2 (6700 ppmV) and water (50-200 ppmV). To reveal the effects of surface morphology, carbon steel coupons with different surface roughness were prepared to expose to CO2 stream containing oxidizing/reducing impurities to observe the condensation and the corrosion process that followed.
This book fulfills its intention to provide a comprehensive overview on 3D-printing of metals.
The interested reader can get a lot of information about the topics one should deal with when working with additively manufactured metallic parts. It gives a general roadmap where to start, what to learn and how it fits together.
This book provides a state‐of‐the‐art overview on the processing, characterization, and modelling of metallic and ceramic materials used for energy and environmental applications. 17 scientists show a collection of current knowledge in 8 chapters.
This book fulfills its intention to provide a reference book containing a collection of publications on thin films and coatings made of ceramic and metals used for energy and environmental applications. It covers a broad range of this topic and provides a comprehensive insight. Graduate and undergraduate students of materials science and mechanical engineering can find an overview on this topic to step in this interesting field of engineering.
The copper alloyed stainless steel 1.4542 (X5CrNiCuNb16-4) is used in different areas due to its good mechanical properties and corrosion resistance. Strength and corrosion resistance can be adjusted by the heat treatment, which is of importance for the application of this alloy. The mechanical properties (strength and hardness) are attributed to the dispersive precipitation of the copper rich ε–Phase. The additional precipitation of chromium carbides can reduce the corrosion resistance. Different ageing states were produced to investigate the precipitation behaviour with various methods. Furthermore, the influence of cold-rolling on the precipitation behaviour was studied in comparison to a solution annealed state without deformation. The microstructure was studied by SEM and the variations of hardness and magnetic proportion were characterised. The electrochemical potentiodynamic reactivation (EPR) was used to determine the corrosion resistance and detect chromium depletion in all heat-treated states. The results show that a work hardening accelerates the precipitation rate, while ageing at 600 °C reduces the corrosion resistance due to chromium depletion.
The copper alloyed stainless steel 1.4542 (X5CrNiCuNb16-4) is used in different areas due to its good mechanical properties and corrosion resistance. Strength and corrosion resistance can be adjusted by the heat treatment, which is of importance for the application of this alloy. The mechanical properties (strength and hardness) are attributed to the dispersive precipitation of the copper rich ε–Phase. The additional precipitation of chromi-um carbides can reduce the corrosion resistance. Different ageing states were produced to investigate the precipitation behaviour with various methods. Furthermore, the influence of cold-rolling on the precipitation behaviour was studied in comparison to a solution annealed state without deformation. The microstructure was studied by SEM and the variations of hardness and magnetic proportion were characterised. The electrochemical potentiodynamic reactivation (EPR) was used to determine the corrosion resistance and detect chromium depletion in all heat-treated states. The results show that a work hard-ening accelerates the precipitation rate, while ageing at 600 °C reduces the corrosion resistance due to chromium depletion.