The Effects of Combined Laser Cladding and Layer-by-Layer Remelting on the Forming Quality and Properties of H13 Steel Clad Layers

To improve the forming quality, microstructural characteristics, and mechanical properties of multi-track multilayer laser-clad H13 steel structures, a combined laser cladding and layer-by-layer remelting process was employed. The basic cladding parameters were comprehensively evaluated using an orthogonal experimental design combined with the entropy weight method–gray relational analysis (EWM-GRA), while the remelting parameters were determined through a full-factorial experiment. Multi-track multilayer specimens with and without layer-by-layer remelting were subsequently compared in terms of forming characteristics, microstructure, and mechanical properties. Within the investigated parameter range, the preferred cladding parameter combination was a laser power of 1300 W, scanning speed of 12 mm/s, and powder feed rate of 13 g/min, while the preferred remelting parameter combination was 780 W and 18 mm/s. Layer-by-layer remelting produced a smoother surface with less pronounced inter-track overlap traces. Qualitative examination of the cross-sections suggested a tendency toward fewer locally observed pores and reduced variation in microstructural morphology among regions at different heights. The average microhardness increased from 756.9 HV to 789.5 HV, while the ultimate tensile strength and yield strength increased from 1524.23 MPa and 1173.37 MPa to 1604.46 MPa and 1342.88 MPa, respectively. The increased strength was accompanied by reduced elongation after fracture, from 2.57% to 1.41%. These results provide a reference for process parameter selection and property tailoring of layer-by-layer remelting in multi-track multilayer laser-clad H13 steel structures.