Laser powder bed fusion residual stresses: Measurement agreement, machine parity, and baseplate-driven heat-treatment response of 316L stainless steel

Residual stresses were quantified in a 316 L stainless steel additive manufacturing benchmark arch to assess part-to-part and machine-to-machine variability and the influence of baseplate during stress-relief heat treatment. Nominally identical arches were built by laser powder bed fusion (LPBF) on a MetalFAB1 and an EOS M290 using each vendor’s recommended process window, then characterized by synchrotron and neutron diffraction. As-built profiles from all scanners showed a consistent peak tensile stress of ∼380 MPa at the top surface and compressive stresses toward the arch apex, with inter-instrument variations (80 ± 50 MPa) comparable to part-to-part differences (50 ± 30 MPa). A 700 °C/2 hour heat treatment reduced near-surface tensile stress by 200 ± 20 MPa (stainless baseplate) and 270 ± 20 MPa (ferritic baseplate), highlighting the role of baseplate thermal-expansion mismatch. The MetalFAB1 residual stress state was modelled using an inherent-strain build simulation and a viscoelastic heat-treatment analysis. Finite-element predictions captured the larger stress reduction assuming a ferritic baseplate (≈255 MPa vs. ≈190 MPa). These results indicate that, for similar deposition schemas operating within a full-density process window target, long-range residual stresses are governed primarily by temperature-dependent yield rather than precise energy–density settings. Baseplate selection and heat-treatment timing therefore provide effective levers for residual-stress mitigation in LPBF 316 L.