Creep behavior of 316 L stainless steel manufactured by laser powder b e d fusion

Additive manufacturing as a new processing technique can produce unique microstructure that is difficult to achieve using conventional techniques. In this study, we have investigated the creep behavior of 316 L stainless steel produced by a laser powder bed fusion process at temperatures of 550, 600 and 650 degrees C and stresses between 175 and 300 MPa. We found that additively-manufactured 316 L stainless steel had a higher stress dependence of the minimum creep rate than conventionally-made Type 316 SS, which could be attributed to the dislocation cell structure resulting from the printing process. The dislocation cell structure was unstable under creep, evolving into a uniform dislocation structure under the test conditions. While internal porosity in AM 316 L SS may serve as nucleation sites of creep voids and may be responsible for a relatively lower creep life, additively-manufactured 316 SS did not show inferior creep ductility when compared with conventionally-made 316 SS. The creep life of AM 316 L SS could be improved by stabilizing dislocation cell structure and/or reducing internal porosity through an optimized additive manufacturing process. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Additive manufacturing of 316L stainless steel shows advantages in creep behavior, such as higher stress dependence of the minimum creep rate and relatively lower creep life. The creep life of AM 316L SS can be improved through optimized manufacturing processes.