Metal Additive Manufacturing Conference 2018

The SLM (Selective Laser Melting) is an additive manufacturing technique (AM) that received in the more recent years an increasing interest for the production of mechanical components in many different technological fields. This technology is based on a layer by layer laser melting of metal powders deposited on a moving stage in order to obtain a controlled geometry of the component (3D printing). Many metals can be processed by using this technique such as Ti, Al or Ni alloys, tool or stainless steels. The aim of this work is to determine the tribological behaviour of an AISI 316L stainless steel produced by 3D printing and to compare these properties to the ones of a wrought AISI 316L stainless steel. The study of the wear performances at high temperature is also considered. This is a remarkable topic, mostly because these mechanical components frequently operate at high temperature. The samples, with a dimension of 20x30x6mm, were produced by SLM (Concept laser) using a chessboard laser scan. The as produced material, as well as the wrought one, were submitted to tribological tests, using a pin on disk geometry, at different temperatures (200°C, 400°C, 600°C). During the tests, the COF was acquired and monitored continuously for the whole test duration. The microstructure was deeply investigated by SKPFM, SEM, and light microscopes both at the contact point and at certain distance from it. Microhardness was also measured. The aim of these analysis was to determine the microstructural evolution of material caused by the testing temperature (thermal treatment) and the applied stresses at the contact point. The top view SEM analysis of the wear track was performed in order to determine the wear mechanism. The wear rate was calculated as a function of the testing temperature. The preliminary analyses have shown that the AM material presents a dual phase microstructure and small defects (porosities) affecting the wear behaviour. A correlation between testing temperature, microstructure evolution and the wear properties has been observed in the AM material.