Influence of Direct Aging on the Mechanical Behavior of Laser Welded 3D-Printed SAE 630 (17-4PH) Stainless Steel Parts

Abstract This study investigates the impact of direct aging on the mechanical properties of 3D-printed and laser welded tensile samples made from SAE 630 (17-4PH) martensitic precipitation-hardened stainless steel. ASTM E8-22 flat subsized tensile specimens were produced using a commercially available industrial additive manufacturing system, utilizing a plastic-matrix-bound commercially available 17-4PH metal powder filament and 100% infill using OEM supplied printing parameters. Four conditions were evaluated, with two samples per condition to ensure data reproducibility. The sample conditions were as follows: (1) as-printed & sintered, (2) welded using an IPG LightWeld 2000 XR handheld laser welding machine (using AWS/SFA A5.9 ER630 filler wire), (3) direct aged per AMS 2759/3J H1150 after printing, and (4) laser-welded followed by direct aging. Tensile testing revealed that direct aging enhances ductility by 118% while reducing the tensile strength by only 21% and still meeting the strength requirements outlined in ASTM A564-13. Direct aging also shifted the failure location from the weld zone to the base material. Additionally, optical scanning was employed to assess dimensional stability due to residual stress evolution across the as-printed, welded, and heat-treated conditions. These findings demonstrate the effectiveness of direct aging in improving the performance of welded 3D-printed 17-4PH stainless steel components.