Abstract
The use of metal additive manufacturing (AM) has strongly increased in the industry during the last years. More specifically, selective laser melting (SLM) is one of the most used techniques due to its numerous advantages compared to conventional processing methods. The purpose of this study is to investigate the effects of process parameters on the microstructural and corrosion properties of the additively manufactured AISI 316L stainless steel. Porosity, surface roughness, hardness, and grain size were studied for specimens produced with energy densities ranging from 51.17 to 173.91 J/mm3 that resulted from different combinations of processing parameters. Using experimental results and applying the Taguchi model, 99.38 J/mm3 was determined as the optimal energy density needed to produce samples with almost no porosity. The following analysis of variance ANOVA confirmed the scanning speed as the most influential factor in reducing the porosity percentage, which had a 74.9% contribution, followed by the position along the building direction with 22.8%, and finally, the laser energy with 2.3%. The influence on corrosion resistance was obtained by performing cyclic potentiodynamic polarization tests (CPP) in a 3.5 wt % NaCl solution at room temperature for different energy densities and positions (Z axis). The corrosion properties of the AM samples were studied and compared to those obtained from the traditionally manufactured samples. The corrosion resistance of the samples worsened with the increase in the percentage of porosity. The process parameters have consequently been optimized and the database has been extended to improve the quality of the AM-produced parts in which microstructural heterogeneities were observed along the building direction.
Highlights
Additive Manufacturing (AM) provides the capability to relax the design and manufacturing constraints by creating products with great geometrical complexity and without the need for extensive machining
This study aims to establish the corrosion properties of the AISI 316L stainless steel (316L SS) produced via selective laser melting (SLM) as compared to conventional production techniques; to explain the corrosion properties of produced components in terms of microstructure and parameters involved in the production process, such as laser energy and scanning speed; and to provide recommendations for process parameters in order to optimize the corrosion resistance of AM processes
The AM stainless-steel specimens were produced in Amsterdam (The Netherlands) at Shell Technology Centre Amsterdam (STCA) in an M2 dual laser machine under argon atmosphere, using 316L metallic powder from General Electric (GE), with a particle size distribution (PSD) of 15–45 μm provided by the supplier
Summary
Additive Manufacturing (AM) provides the capability to relax the design and manufacturing constraints by creating products with great geometrical complexity and without the need for extensive machining. Among the AM techniques, selective laser melting (SLM) is the most versatile, allowing for the creation of functional parts with mechanical properties similar to those of conventionally produced materials [6]. The wide variety of materials that can be produced, together with the low surface roughness achieved, are what differentiates this technique from other production methods [7]. The second layer of metal powder is spread out over the surface, and the same operation is repeated until the building process is completed. This technique still presents some challenges that must be addressed in order to improve the performance of the manufactured parts [8]. The combined action of these parameters can be reduced to the energy density (Ed) in J/mm, which is the input energy received by the sample during the AM process, represented in Equation (1)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
