Akademik Veri Yönetim Sistemi
14th International Conference on Technology of Plasticity, ICTP 2023, Mandelieu-La Napoule, Fransa, 24 - 29 Eylül 2023, ss.344-351
Gradual material loss due to wear causes geometrical deviations in tools and indirectly in part geometries in metal forming applications. Therefore, improvement of forming tool surfaces to prolong tool life is a constant challenge. Conventional hardness enhancement applications include generating a diffusion layer or PVD coating. A recent approach to further enhance surface hardness and increase the hardness depth of metal forming tools is to apply severe shot peening (SSP) prior to nitriding. Dislocation density increase combined with the ultra-fine grains generated after SSP on surface layer provides faster diffusion of nitrogen molecules. However, increase in surface roughness may be observed after SSP which may cause inhomogeneities in nitride layer. In the current study, effect of the initial surface roughness on the final surface topography of 1.2379 tool steel after SSP has been investigated. Three different surface states were generated using grinding, sandpapering and polishing. After hardening the samples to 61 HRC, SSP has been applied on specimens. Studies revealed that SSP decreases surface roughness for ground samples while increasing the same property for sandpapered and polished ones. Moreover, it is found that surface region hardness can be increased via SSP and subsurface microstructure can be altered. Such a modified microstructure may enable better nitride diffusion.