Effects of scanning speed on creep behaviour of 316L stainless steel produced using selective laser melting

Abstract

Increasing numbers of critical components for the aerospace and power industries are fabricated using additive manufacturing (AM). To increase the productivity of high‐temperature components by AM, the scanning speed needs to be maximized without sacrificing the required creep properties. In this study, five rectangular blocks were manufactured using selective laser melting while varying the scanning speed from 420 to 980 mm/s. Small punch creep tests were conducted at 650°C using 10 × 10 × 0.5 mm specimens machined from each block. Creep deformation and rupture life were measured. Power law creep constants were also determined. Difference of creep behaviours were explained based on the microstructures showing pore defects and the measured metal density values. A 3D response surface plot was employed to predict the creep life as a function of the scanning speed and the energy density. As a consequence, a scanning speed range of 416 to 572 mm/s is recommended to maximize productivity and to increase creep resistance.

Effect of Laser Speed and Hatch Spacing on the Corrosion Behavior of 316L Stainless Steel Produced by Selective Laser Melting

“…In the recent years, the AM of AISI 316L has been extensively studied. Although it is a steel for applications where a high resistance to corrosion is necessary, most of the studies are based on the assessment of the microstructural and mechanical properties [10][11][12][13][14][15][16][17]. The microstructure of AM 316L SS consists of very fine interconnected cellular or columnar sub-grains inside each individual large grain of austenite (δ-ferrite may be present in intercellular regions) [18].…”

Effects of processing parameters on creep behavior of 316L stainless steel produced using selective laser melting

“…The chemical composition of the SS316L material is shown in Table 1. During the SLM process, a bidirectional scanning pattern was adopted, and the substrate was pre-heated at 250 °C to obtain the highest block density and avoid balling surface defects [6][7][8][9]. Argon gas was used during the manufacturing process to prevent oxidation.…”

“…SP creep test results of blocks 02-06 in Table 3 showed effect of varying energy density [9]. The minimum creep displacement rate as a function of applied SP load and the creep rupture life as a function of the applied load are shown in Figs.…”

“…Proper creep resistance should be assured for components manufactured by SLM and are designed for high temperature application. This is done by carefully considering the particular microstructures formed during the SLM process [6][7][8][9].…”

“…Regarding the creep of SLM materials, Williams et al investigated the effects of multiaxial stress on the creep behavior of SS316L for different building orientations [25]. The small punch (SP) creep test technique was applied to study the creep resistance of SLMmanufactured blocks of SS316L [6][7][8][9].…”