Thermal compensation strategy in selective electron beam melting: Tailoring the microstructure and mechanical properties of H13 tool steel

• Thermal compensation optimizes microstructure in SEBM-fabricated H13 steel. • Distinct microstructures exhibit significant performance differences. • Mixed martensite and bainite H13 steel achieve optimal strength and ductility. • Optimized mechanical properties surpass conventional manufacturing methods. H13 tool steel has extensive application in the mold manufacturing industry due to its excellent thermal strength and wear resistance. However, additively manufactured H13 exhibits inferior mechanical properties, high residual stress, and high volume fraction of retained austenite, which limits its application. To solve this problem, our work aims to optimize the microstructure and mechanical properties of H13 steel using Selective Electron Beam Melting (SEBM) with different thermal compensation strategies. The microstructural evolution and mechanical property strengthening mechanism of SEBM-fabricated H13 steels were discussed. The results indicated that the microstructure of H13 steel is a mixture of bainite and martensite, achieving an optimal balance between strength of 1809 ± 11 MPa and plasticity of 10.48 % when the thermal compensation current was 40 mA. This can be attributed to adjustments in grain size, dislocation density, and precipitate phases during thermal compensation strategies. The synergistic strengthening effects of high density of dislocations, numerous fine V 8 C 7 precipitates, and refined grains result in mechanical properties that surpass those of other additive manufacturing and conventional methods. Therefore, controlled thermal compensation was an effective tool for regulating the microstructure and mechanical properties of materials, providing a valuable reference for the fabrication of high-performance H13 steel components.