Hard machining of agricultural machines parts
R. Drlička, J. Žarnovský, R. Mikuš, I. Kováč, M. Korenkohttps://doi.org/10.17221/50/2012-RAECitation:Drlička R., Žarnovský J., Mikuš R., Kováč I., Korenko M. (2013): Hard machining of agricultural machines parts. Res. Agr. Eng., 59: S42-S48.
For the renovation and/or improvement of the surface properties of machine elements, hard facing is often used. Hard structures obtained in layers or by heat treatment achieve a hardness of up to 68 hardness (HRC) or even more. The grinding of these surfaces demands the use of processing fluids and causes sometimes changes in the surface layers structure. Hard turning can replace grinding when certain requirements are fulfilled, particularly tough machining system. Hard deposits of two weld-on materials on a sample of steel grade S235JRG1 have been turned using cemented carbide inserts with a TiAlN coating of PVD type. The surface roughness measurements along with the observation of insert wear have been conducted to find proper machining parameters and conditions for this application. Cutting inserts manufacturer guidelines for special application could be insufficient or even not provided. Besides that, it is necessary in the experiments to take into account and examine the cutting ceramics and cubic boron nitride (CBN)/polycrystalline cubic boron nitride (PCBN). Keywords:
hard turning; tool wear; surface quality; roughness; hardness