Self-heating behavior during cyclic loadings of 316L stainless steel specimens manufactured or repaired by Directed Energy Deposition

Abstract

The purpose of this article is to assess a self-heating testing method for the characterization of fatigue properties of single-track thickness additively manufactured specimens. It also evaluates the impact of the microstructure orientation with respect to the loading direction on the dissipative behavior and the initiation of microcracks. The 316L stainless steel specimens under scrutiny were manufactured by Directed Energy Deposition in two configurations: (i) fully printed specimens (2 orientations) and (ii) repaired specimens. The paper first presents a morphologic and crystallographic texture analysis and second, a series of self-heating tests under cyclic loading. The microstructural analysis revealed elongated grains with their sizes, shapes and preferred orientations controlled by process parameters. The self-heating measurements under cyclic tensile loading proved that the dissipation estimation through infrared measurements can be performed on small scale, thin specimens. The self-heating curves could successfully be represented by the Munier model. Moreover, several links between the printing parameters and self-heating results could be established. For example, a smaller vertical increment between successively deposited layers leads to higher mean

Hybrid subtractive–additive manufacturing processes for high value-added metal components

“…7 Process plan alternatives generated for the particular case study treatment. Although 316L cannot be heat treated, AM of 316L alloys has been successfully used in the past [32][33][34][35][36][37], even for repair purposes [38], and its fatigue life has been deemed satisfactory [39][40][41]. The processes used in this case are DLM, milling, and vision-based metrology, but additional processes could be considered as appropriate.…”

Tensile and ductile fracture properties of as-printed 316L stainless steel thin walls obtained by directed energy deposition

“…It has been observed that additively manufactured 316L exhibits higher yield stress and ultimate tensile strength than conventionally manufactured 316L, and a lower elongation to failure and fracture toughness [19]. In addition, the influence of layer orientation and surface roughness on the fatigue behavior of SLM parts were addressed in [20,21]. The ability to manufacture 316L stainless steel parts using the DED additive manufacturing technology have been investigated in a number of recent works [22][23][24][25][26][27][28].…”

Experimental investigation of the fatigue crack growth behavior in wire arc additively manufactured ER100S‐1 steel specimens

“…5 In addition to the fabrication of new parts, the WAAM technique also facilitates the repair of damaged structures, as an alternative to the replacement of the entire component. 6,7 Similarly to all AM techniques, as well as all the advantages mentioned for WAAM, this technique may also involve some disadvantages. The main disadvantage of such a fabrication method is the possibility of relatively high roughness on the outer surface of the as-built parts and dimensional inaccuracies that may impose the requirement of further post-deposition treatments such as surface machining, high pressure rolling, etc.…”