Residual stresses of wire arc additively manufactured stainless steel square hollow section members

This paper investigates the residual stresses of wire arc additively manufactured (WAAM) stainless steel square hollow section (SHS) members. The WAAM SHS members were fabricated by feedstock wire ER308L with a diameter of 1.2 mm. Tensile coupon tests and grading calibration tests were conducted to obtain the strain release coefficients (SRCs) and calibration constants (CCs). Four specimens were tested subsequently using the hole-drilling method to obtain the residual stress distributions of WAAM stainless steel 308L SHS members. For longitudinal membrane residual stresses, a consistent tensile–compressive–tensile pattern was observed in each plate. For transverse membrane residual stresses, a tensile–compressive–tensile pattern was observed in each plate at midspan sections, contrasting with a compressive–tensile–compressive pattern at end sections. Bending residual stresses were negligible in both directions without distinct distribution patterns. The general distribution and the effects of deposition path and heat treatment are discussed. Additionally, the test results are compared with existing residual stress distribution models for conventionally fabricated carbon steel and stainless steel SHS members. The new residual stress distribution models for WAAM stainless steel SHS members with and without heat treatment are proposed and assessed. Comparing to the existing models for conventionally fabricated SHS members, the proposed models provides more accurate and consistent predictions.