Session: MF-16-01 Creep and Creep-Fatigue Interaction

Paper Number: 61836

Start Time: Tuesday, July 13, 2021, 05:00 PM

61836 - Creep Damage Predictions Under Multiaxial Conditions for 316L Stainless Steel Samples Manufactured by Laser Powder Bed Fusion 

316L stainless steel, used mainly in high-temperature applications, can be manufactured by laser powder bed fusion (LPBF). However, the high-temperature LFBF manufacturing process can lead to undesirable multiaxial residual stresses (RS), which may require relaxation by heat treatments. The high residual stresses combined with high operating temperatures will induce creep deformation and damage processes. Therefore, it is important that the creep behaviour of LPBF 316L under multiaxial stress conditions is understood and models developed to predict the creep deformation and damage processes. Creep tests have previously been performed on notched bar test samples of two different notched acuities to examine the influence of stress triaxiality on creep failure behaviour. The notched bar samples were built in both the horizontal and vertical orientations (i.e. parallel and perpendicular to the build direction).

In this work, a FE modelling methodology has been developed to simulate the deformation behaviour of these notched bars and creep damage models implemented to predict the damage evolutions and final failure.  Creep damage models have based on a ductility exhaustion approach have been employed and compared to the experimental results. Both the vertical and horizontal sample orientations have been modelled for two notch geometries. This has enabled the effects of build orientation and initial processing defects on creep performance to be assessed.

Presenting Author: Daniel J Burridge Imperial College London

Authors:

Daniel J Burridge Imperial College London
Catrin M. Davies Imperial College London