Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Analysis of dewaxing and sintering of steel powder compacts

Classical analysis of powder sintering is not relevant to describe the sintering of dense metal powder compacts. In particular it cannot explain the deformation of such compacts, which is very small (typically less than 1%), strongly anisotropic and significantly affected by pressing and dewaxing conditions. From the information collected by various methods (dilatometry, impulse excitation technique, mechanical testing, X-ray microtomography) a description of the dewaxing and sintering process of steel powder compacts has been worked out. It points out the prominent role of so-called contact pores, which are created during compact ejection, on the deformation and strengthening of the material during heating. These pores are more numerous in denser compacts and preferentially oriented perpendicularly to the pressing direction. They tend to open during dewaxing, which results in swelling and weakening of the compact, and to close early during sintering, which leads to a larger shrinkage in the pressing direction with respect to the transverse direction.

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Reported by

Institut National Polytechnique de Grenoble
Laboratoire GPM2, ENSPG, BP 46