An efficient laser-CMT+P additive manufacturing process for large 316 L components

To reduce forming defects in additive manufacturing (such as sagging, seam bulges, and surface irregularities) and to achieve additive manufacturing with low heat input, automation, high efficiency, and stability, this study innovatively proposes a novel spatially flexible dual-pulse hybrid process that integrates low-heat-input, low-power pulsed lasers with CMT+Pulse technology. The results show that laser-assisted thermal regulation coupled with pulsed molten pool stirring improves molten pool stability and deposition continuity. Optimized shielding gas flow of 15 L/min and a 15% overlap ratio suppressed lack-of-fusion defects and improved layer stacking quality. The deposited structure comprised dendritic-shaped γ-austenite and δ-ferrite phases. The final product showed a UTS of 669 MPa, a maximum EL of 51%, and a maximum YS of 0.2% of 389 MPa. Its suitability for large-scale metal structures was demonstrated by the successful fabrication of a massive circular 316 L component.