PSI - Issue 23

Jozef Majerík et al. / Procedia Structural Integrity 23 (2019) 541–546

546

Jozef Majerík et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 2. Measured nano-hardness courses of (a) hard finish turned and (b) cylindrically grinded surface layers depending on the measured depth under the machined surfaces. – microstructure is slightly heterogeneous, relatively coarse grained, and consists of high tempered martensite and bainite, along with fine globular secondary carbides, – results of AFM metallographic analysis of the cross-section of the specimens showed different changes in the structure of the sam ple’s surface layer after hard finish turning and grinding, – obtained nano-hardness values show that the hardened layer of the hard finish turned surface is well cohesive to the base material and is not mechanically damaged against grinded surfaces. In particular, the increased hardness of turned layer increases the wear resistance of the surface, from which a longer lifetime can be derived. For future investigations of the evaluated integrity parameters of tested specimens it might also be advisable to measure cutting tool wear or residual stresses, along with implementing a more complete concept of surface integrity to complement purely functional tests.

Acknowledgements

This work was supported by the Slovak Research and Development Agency under the contract No. APVV-15-0710.

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