from the conferences organized by TANGER Ltd.
It has been observed that the products obtained by means of 3D printing technology, even in the case of consideration of optimal parameters of printing technology recommended by the manufacturers of metal powders laser sintering systems, are characterized by certain structural discontinuities (pores and unmelted powder) in surface layer. Therefore, surface modification via shot peening is considered suitable for additive manufacturing of parts made of 17-4PH stainless steel. The specimens have been produced by means of EOSINT M280 system dedicated for laser sintering of metal powders. The objective of this study was to determine the effect of shot peening pressures (0.4 MPa and 0.6 MPa) and two types of blasting media (CrNi steel shot and ceramic beads based on ZrO2) on the tribological characteristics, surface topography and hardness of specimens of DMLS 17-4PH stainless steel. Wear tests have been carried out by means of ball-on-disc tribotester in dry sliding method at room temperature (about 22ºC). Wear loss after tribology testing was calculated via profilometry measurements of the worn surface, i.e. wear grooves, using contact profilometer. Finally, the wear mechanism was investigated using a scanning electron microscope (SEM). Adhesive and abrasive wear were two predominant mechanisms of tribological deterioration. The general results of all tests indicate to favourable effect of shot peening process on the hardness and wear resistance of 17-4PH steel. The highest increase in hardness was obtained for the surfaces modified by steel shot and ceramic beads using a peening pressure of 0.6 MPa, respectively mean: 550±34 HV0.3 and 554±22.2 HV0.5. DMLS 17-4PH specimens modified by shot peening using steel beads and a pressure of 0.6 MPa exhibited the optimum surface morphology, hardness and microstructure, and thus improved wear.
Keywords: Additive manufacturing, 17-4PH steel, shot peening, direct metal laser sintered, wear resistance© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.