Additive/subtractive hybrid manufacturing of 316L stainless steel powder: Densification, microhardness and residual stress

316L stainless steel specimens were manufactured by additive/subtractive hybrid manufacturing (ASHM). The densification level, mi-crostructure, microhardness and residual stress characterization in the different zones of the part were investigated. The density was determined by the Archimedes method, and the density measurement was divided into three regions, namely, the bottom, middle and top zones. The results show that the middle zone has a much smoother melting surface and that a relative density of nearly 100 % was achieved for the part in this study. The hardness profiles at room temperature, along the width and height directions of the cross-section of the top and bottom zones, were also studied. The residual stress was evaluated by X-ray diffraction (XRD) for the 316L SS specimen fabricated by the ASHM process, and it was compared with a specimen manufactured by the additive laser directed energy deposition (DED) process. The results show that the top and bottom zones exhibit tensile stress, and compressive stress occurs in the middle area. Moreover, the residual stress of ASHM shows a slightly smaller trend than that of the simplex DED due to the stress relaxation of the subsequent subtractive milling. These results may offer guidance for ASHM-fabricated 316L parts.

[1]  Sehyung Park,et al.  3D welding and milling: part II—optimization of the 3D welding process using an experimental design approach , 2005 .

[2]  Yang Wang,et al.  A complete study on satellite thruster structure (STS) manufactured by a hybrid manufacturing (HM) process with integration of additive and subtractive manufacture , 2017 .

[3]  D. Shim,et al.  Study of the effects of process parameters on deposited single track of M4 powder based direct energy deposition , 2017 .

[4]  Edward William Reutzel,et al.  Effect of processing conditions on the microstructure, porosity, and mechanical properties of Ti-6Al-4V repair fabricated by directed energy deposition , 2019, Journal of Materials Processing Technology.

[5]  Pingfa Feng,et al.  Prediction of surface residual stress after end milling based on cutting force and temperature , 2016 .

[6]  M. Pace,et al.  3D additive manufactured 316L components microstructural features and changes induced by working life cycles , 2017 .

[7]  P. Withers,et al.  Residual stress. Part 1 – Measurement techniques , 2001 .

[8]  A. Kromm,et al.  Effect of hatch length on the development of microstructure, texture and residual stresses in selective laser melted superalloy Inconel 718 , 2017 .

[9]  M. Yakout,et al.  Density and mechanical properties in selective laser melting of Invar 36 and stainless steel 316L , 2019, Journal of Materials Processing Technology.

[10]  F. Lu,et al.  Improved high-temperature hardness and wear resistance of Inconel 625 coatings fabricated by laser cladding , 2017 .

[11]  Pan Michaleris,et al.  Effect of stress relaxation on distortion in additive manufacturing process modeling , 2016 .

[12]  Doo-Sun Choi,et al.  3D welding and milling: Part I-a direct approach for freeform fabrication of metallic prototypes , 2005 .

[13]  N. Shamsaei,et al.  Effects of process time interval and heat treatment on the mechanical and microstructural properties of direct laser deposited 316L stainless steel , 2015 .

[14]  Y. Gong,et al.  Densification, surface morphology, microstructure and mechanical properties of 316L fabricated by hybrid manufacturing , 2018 .

[15]  Steven Y. Liang,et al.  Effects of depth of cut on the redistribution of residual stress and distortion during the milling of thin-walled part , 2015 .

[16]  Jianfei Sun,et al.  Effect of Machining Parameters on Surface Integrity in High Speed Milling of Super Alloy GH4169/Inconel 718 , 2016 .

[17]  Eric Coatanéa,et al.  Comparative environmental impacts of additive and subtractive manufacturing technologies , 2016 .

[18]  I. Todd,et al.  Reduction of micro-cracking in nickel superalloys processed by Selective Laser Melting: A fundamental alloy design approach , 2015 .

[19]  S. R. Chen,et al.  Structure/property (constitutive and spallation response) of additively manufactured 316L stainless steel , 2017 .

[20]  Moataz M. Attallah,et al.  Selective laser melting of Invar 36: Microstructure and properties , 2016 .

[21]  Fei Yan,et al.  A study of microstructures and mechanical properties of laser welded joint in GH3030 alloy , 2018, Journal of Mechanical Science and Technology.

[22]  Guillaume Mandil,et al.  Process planning for combined additive and subtractive manufacturing technologies in a remanufacturing context , 2017 .

[23]  J. Kruth,et al.  Residual stresses in selective laser sintering and selective laser melting , 2006 .

[24]  Guillaume Mandil,et al.  The development of a strategy for direct part reuse using additive and subtractive manufacturing technologies , 2018, Additive Manufacturing.

[25]  Konstantinos Salonitis,et al.  Additive manufacturing and post-processing simulation: laser cladding followed by high speed machining , 2016 .

[26]  Bo-Sung Shin,et al.  Development of a direct metal freeform fabrication technique using CO2 laser welding and milling technology , 2001 .

[27]  Alessandro Fortunato,et al.  Effect of Selective Laser Melting (SLM) process parameters on microstructure and mechanical properties of 316L austenitic stainless steel , 2017 .

[28]  Jenn‐Ming Yang,et al.  Densification behavior, microstructural evolution, and mechanical properties of TiC/316L stainless steel nanocomposites fabricated by selective laser melting , 2018 .

[29]  Guilan Wang,et al.  Metal direct prototyping by using hybrid plasma deposition and milling , 2009 .

[30]  Y. Ni,et al.  Residual stress measurement on propellant tank of 2219 aluminum alloy and study on its weak spot , 2017 .

[31]  S. Liang,et al.  Residual stress prediction in laser-assisted milling considering recrystallization effects , 2019, The International Journal of Advanced Manufacturing Technology.

[32]  Richard A. Wysk,et al.  Development of a modular computer-aided process planning (CAPP) system for additive-subtractive hybrid manufacturing of pockets, holes, and flat surfaces , 2018 .

[33]  Masahiko Mori,et al.  Innovative grid molding and cooling using an additive and subtractive hybrid CNC machine tool , 2017 .

[34]  Vimal Dhokia,et al.  Investigation of part distortions as a result of hybrid manufacturing , 2016 .