Ferrium S53® is a new secondary hardening ultra-high-strength (UHS) stainless steel, with more Cr than other Co–Ni UHS steels (UHSSs). The solid-solution step is an important step in the heat treatment of Ferrium S53®. This study investigated the effect of solid-solution temperature on the microstructure and mechanical properties of Ferrium S53®. Steel samples were solid-solution-treated at six different temperatures between 935 °C and 1185 °C for one hour. The resulting microstructures were characterized by X-ray diffraction (XRD), optical microscopy, field emission scanning electron microscopy, and transmission electron microscopy. The tensile strength and impact toughness at different solid-solution temperatures were also evaluated, and their relationship with the microstructure was discussed. The secondary phase of Ferrium S53® steel precipitated during stress annealing was M₂₃C₆, mostly around 100 nm, having C, Cr, Mo, and W as main components. After one hour of solid-solution treatment at 1035 °C, the steel was entirely austenitized, but up to 1085 °C, the secondary phase was completely dissolved. The increase of the solid-solution temperature increased the retained austenite content and the toughness and led to the dissolution of the secondary phase. The last one is the main reason for the change of strength. The experimental results showed that the most appropriate solid-solution temperature for Ferrium S53® is 1085 °C.

FerriumS53®是一种新型的二次硬化超高强度（UHS）不锈钢，其铬含量高于其他Co-Ni UHS钢（UHSSs）。固溶步骤是FerriumS53®热处理中的重要步骤。这项研究调查了固溶温度对FerriumS53®的微观结构和力学性能的影响。将钢样品在935°C和1185°C之间的六个不同温度下固溶处理1小时。通过X射线衍射（XRD），光学显微镜，场发射扫描电子显微镜和透射电子显微镜对所得的微结构进行表征。还评估了在不同固溶温度下的拉伸强度和冲击韧性，并讨论了它们与微观结构的关系。₂₃ C ₆，主要在100 nm附近，具有C，Cr，Mo和W作为主要成分。在1035°C下进行一小时的固溶处理后，钢被完全奥氏体化，但是直到1085°C，第二相才完全溶解。固溶温度的升高增加了残余奥氏体含量和韧性，并导致第二相的溶解。最后一个是强度变化的主要原因。实验结果表明，FerriumS53®的最合适固溶温度为1085°C。