Effect of interconnected porosity on carbon diffusion depth in vacuum carburising process of iron compacts

Abstract

The research work was aimed at determining the influence of macro- and micropores on carbon diffusion depth in the process of vacuum carburising of iron compacts with density within 5·6 to 6·4 g cm–3. Vacuum carburising of the compacts made of iron powder ASC100·29 was performed at 1050°C in a laboratory vacuum furnace. The carburising effects were compared and evaluated in terms of thickness, structure and surface carbon content of the case. Simplified carbon concentration gradients in the carburised layers were determined for the examined densities. Empirical relationships were formulated for carbon content in the case at a fixed distance from the surface as a function of the compact density for the accepted process parameters. It was found that interconnected macropores are decisive for the carburising depth.