Berlin 2005 – scientific programme

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M: Metallphysik

M 32: Poster TU B (Symposium Tomographic Methods in Materials Research M-32.32-55)

M 32.23: Poster

Monday, March 7, 2005, 14:30–16:30, Poster TU B

New Expression for the Diffusivity of Carbon in Fe-C Austenite — •Jürgen Gegner — SKF GmbH, Material Physics, Ernst-Sachs-Str. 5, D-97424 Schweinfurt

In engineering technology of particularly case or through hardenable low-alloyed steels, precise mathematical prediction and analysis of carbon solid-state diffusion profiles is of special importance to proper heat treatment process control (carburization) and failure inspection (decarburization). Thus, reliable input data is required for correct simulations. Evaluating three discrete literature sources, for the concentration dependence of the carbon diffusivity in austenite linearized representations suitable for computing-time saving iterative calculations are derived between 0 and 1.4 m.% C and fitted with respect to temperature in the practically most relevant range form 1073 to 1373 K by means of two equivalent defining equations based on a simple polynomial expression and a physically founded Arrhenius approach, respectively. An extensive comparison to available literature references, which are partly inconsistent with each other, is drawn. The mathematical analysis of an industrial two-step gas carburizing experiment demonstrates the potential of the new expression.