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 degrees C using 10 x 10 x 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.