Comparative Analysis of Wear Properties of 440C Tool Steel Fabricated by Spray Forming and Conventional Casting

Abstract Spray forming is a rapid solidification manufacturing technique that produces finer grains and more homogeneous carbide distribution, which leads to improved mechanical properties compared to conventional cast processes. This research compares the wear resistance of heat-treated AISI 440C martensitic stainless steel produced via conventional casting and spray-forming, emphasizing how the process-structure influences the wear behavior. The microstructures of the alloys were characterized using x-ray diffraction, scanning electron microscopy, and electron backscatter diffraction to correlate microstructural characteristics with wear performance. The wear resistance of each material was evaluated using a dry sliding ball-on-disk configuration at room temperature. In both materials, the primary wear mechanism was oxidative, with minor indications of adhesive and abrasive wear. The results showed that the spray-formed (SF) steel exhibited up to 24% reduction in the specific wear rate compared to its conventionally cast counterpart. This improvement in SF material can be attributed to the higher fraction of Cr 23 C 6 carbide, a finer and more homogeneous Cr 23 C 6 carbide distribution, and lower carbide near neighbor distance within a martensitic matrix, which reduces material loss during wear by increasing matrix support and decreasing abrasive and adhesive wear mechanisms.