18Ni(350) martensitic age-hardening steel is a high-strength and high-toughness stainless steel, belonging to high-performance alloy steel. With its excellent strength, toughness, high-temperature resistance and corrosion resistance, it is widely used in high-performance fields such as aviation, aerospace and automobiles.

Aging precipitation phase: During the subsequent aging treatment process, the martensite phase undergoes transformation, and alloying elements in the steel (such as nickel, chromium, molybdenum, etc.) will precipitate strengthening phases, forming nanoscale precipitates, further enhancing the mechanical properties of the steel. This organizational structure enables 18Ni(350) steel to possess both high strength and good plasticity and toughness after aging treatment, especially demonstrating outstanding mechanical properties in high-temperature environments.

Chemical composition（%）

Performance characteristics of 18Ni(350)

Mechanical properties

Tensile strength: approximately 1500MPa. Some data indicate that the tensile strength is ≥2490MPa. In situations with high strength requirements, it is particularly suitable for high-load working environments such as aero engines.

Yield strength: approximately 1200MPa. It has a relatively high yield strength and can withstand considerable external forces without undergoing plastic deformation.

Elongation: Approximately 10-12%, and the elongation after fracture can usually reach around 12%. Despite its high strength, it also has good ductility, which can meet the manufacturing requirements of complex-shaped parts and adapt to complex load environments.

Hardness: After aging treatment, the hardness can reach 45-50HRC, featuring high wear resistance and durability.

Aging treatment

After quenching, steel undergoes aging treatment, typically at a temperature of 450-550 ° C. The aging time varies depending on the alloy composition and required properties, usually ranging from 2 to 6 hours. The aging process leads to the precipitation of strengthening phases, further enhancing the strength and hardness of the steel. Some data also show that the solution temperature is generally controlled at 1050 to 1150℃, with a holding time of about 1 hour. Aging treatment is usually carried out at 480 to 520℃, and the holding time is adjusted according to different cross-sectional dimensions.