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 32.24: Poster

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

New Computer Model for Decarburization of Steels with Simultaneous Carbide Dissolution — •Jürgen Gegner — SKF GmbH, Material Physics, Ernst-Sachs-Str. 5, D-97424 Schweinfurt

Decarburization, i.e. outward diffusion of carbon caused by oxidation reactions, seriously impairs the mechanical edge zone properties of the affected material. This process represents the most important undesirable side effect to common heat treatment (e.g. austenitizing, soft annealing) and hot-working operations (e.g. forging, upsetting) of particularly low-alloyed steels. Reliable simulation tools are thus required for substantiated failure analyses. If the initial carbon content of the steel exceeds its solubility in austenite, decarburization is accompanied by carbide dissolution and thus becomes a complex diffusion process with simultaneous chemical reaction. A realistic computer model for the involvement of this background process, based on an iterative solution of Fick’s law, is developed. Applying the novel calculation tool, the effect of the rate constant of carbide dissolution on the carbon profiles is discussed in detail considering decarburization of standard rolling bearing steel 100Cr6 (SAE 52100) in contaminated protective atmosphere under usual austenitizing conditions at 1123 K as example.