Verwendung nichtmetallischer Werkstoffe zur Verringerung von Korrosionsschäden

Use of non-metallic materials for reducing corrosion damage This paper discusses the application of non-metallic materials for corrosive working conditions. With regard to composite systems metal/non-metal many non-metallic materials nowadays have gained considerable importance. The paper concentrates on non-metallic coatings to protect metals against corrosion hazards. In particular, the groups of materials available, their properties, and the latest developments relating to coating processes are described in detail. It is demonstrated that composite structures have combined the properties of both groups of materials and thus opened up new possibilities for the future.     

Bücherschau

Ohne Zusammenfassung VDI     

Unterschiedliches Aufkohlungsverhalten von Schleudergußrohren aus G-X 40 NiCr 35 25 (W.-Nr. 1.4857) in einem Cracker zur Äthylenherstellung

Carburization of centrifugally cast tubes in the petrochemical industries and explication of this behaviour by laboratory tests with chromium nickel steels and chromium nicked materials in the temperature range 800 to 1150°C The carburization behaviour of the tubes used under the conditions of petrochemical cracking processes depends in a first line on the temperature. Up to 1000°C carbon pickup is low, but above 1050°C heavy carbon pickup and increasing carburization depth must be counted with. This temperature dependence is due to the fact that at 1050°C equilibrium is attained between chromium oxide and carbide, so that the oxide is no longer stable and the original protective effect of the oxide layer is lost. It is for this reason that pre-oxidation of the tubes has not only favourable effects: during cooling cracks may form in the oxide layer, so that carburization of a surface layer may set in at temperatures as low as 800°C. Carburization is delayed by high Cr, Ni and Si contents: for uses at 1100°C at least 28% Cr, 32% Ni and 2.5% Si are required.     

Formänderungen bei der plastischen Durchbiegung von gekerbten Rechteckstäben

Formänderungsmessungen an den Seitenflächen, im Kerbgrund und auf der Stauchseite von gekerbten Biegeproben nach Vierpunktbelastung bis zu hohen, stufenweise gesteigerten Durchbiegungen und örtlichen Formänderungen bis über 100%.     

Werkstoffauswahl in der Chemischen Verfahrenstechnik

Choice of Materials of Construction for Chemical Process Engineering. The choice of appropriate materials is of critical importance for the trouble-free operation of chemical plant and for economic production. Questions of materials should therefore be considered at an early stage of process development. As a rule, the boundary conditions having a direct influence on the choice of materials are communicated by the process engineer to the materials scientist. Several approaches to the proper choice of materials are usually possible. This choice must ensure that adequate safety reserves are available without making the plant unnecessarily expensive. Although numerous methods are available for determining the properties of materials, testing under operating conditions for specific applications is the optimal approach. The experience amassed by materials experts in practice is an extremely important and indispensable factor because there is much knowledge which cannot simply be expressed in equations and numbers.