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

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 sub-sized tensile specimens were produced using the Markforged Metal X™ 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 94% while reducing the tensile strength by only 19% 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, laser scanning was employed to assess 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.