Ferritic stainless steels (FSSs) have attracted considerable attention due to their excellent corrosion resistance and significantly lower cost compared with nickel-bearing austenitic stainless steels. However, the high-temperature wear behavior of additively manufactured FSS 430 has not yet been thoroughly investigated. This study aims to examine the microstructural characteristics and wear properties of laser powder directed energy deposition (LP-DED) FSS 430 fabricated under varying laser powers and hatch distances. Wear testing was conducted at 25 °C and 300 °C after subjecting the samples to solution heat treating at 815 °C and 980 °C for 1 h, followed by forced fan cooling. For comparison, an AISI 430 commercial plate was also tested under the same test conditions. The microstructural evolution and worn surfaces were analyzed using SEM-EDS and EBSD techniques. The wear performance was evaluated based on the friction coefficients and cross-sectional profiles of wear tracks, including wear volume, maximum depth, and scar width. The average friction coefficients (AFCs) of the samples solution heat treated at 980 °C were higher than those treated at 815 °C. Additionally, the AFCs increased with hatch distance at both testing temperatures. A strong correlation was observed between Rockwell hardness and wear resistance, indicating that higher hardness generally results in improved wear performance.

The aim of this work is to study the phase transformations, microstructures, and mechanical properties of ferritic stainless steel (FSS) 430 deposits on martensitic stainless steel (MSS) 410 base metal (BM) using laser powder-directed energy deposition (LP-DED) additive manufacturing. The LP-DED additive manufactured FSS 430 deposits on MSS 410 BM underwent post-heat treatment at 815 °C and 980 °C for 1 h, respectively. The analyses of phase transformations and microstructural evolutions of LP-DED FSS 430 on MSS 410 BM were carried out using X-ray diffraction, SEM, and EBSD. The highest strain was observed at the coarsened chromium carbide (Cr₂₃C₆) in the joint interface between AM FSS 430 and MSS 410 MB. This contributed to localized lattice distortion and mismatch in crystal structure between chromium carbide and the surrounding ferrite. Tensile strength properties at elevated temperatures were discussed to investigate the effects of the different post-heat treatments. The tensile properties of the as-built samples including tensile strength of about 550 MPa and elongation of about 20%, were the same as those of the commercial FSS 430 material. Tensile properties at 500 °C indicated a modest increase in tensile strength to 540–550 MPa. The specimens heat treated at 980 °C retained higher tensile strength than those heat treated at 815 °C. This would be attributed to the grain refinement from prior LP-DED microstructure and chromium carbide coarsening at higher heat treatment, which can increase dislocation density and yield harder mechanical behavior.