Characteristics of ASTM A240 317L Steel
Excellent Corrosion Resistance
High Molybdenum Content: The molybdenum content of 317L steel (3.0%-4.0%) is significantly higher than that of 316L steel (2.0%-3.0%), enabling superior resistance to pitting and crevice corrosion in chloride-, sulfide-, and acidic environments. For example, it exhibits extremely low corrosion rates in 5% sulfuric acid (≤49°C) and can tolerate higher concentrations of acidic conditions for short durations.
Sensitization Resistance: The low carbon content (≤0.030%) minimizes chromium carbide precipitation during welding, reducing the risk of intergranular corrosion. This makes it suitable for large-section welded components that cannot be annealed or require low-temperature stress relief.
High-Temperature Oxidation Resistance: In oxidative environments at ≤871°C, a stable surface oxide film forms, making it ideal for high-temperature components (e.g., valve shaft sleeves).
High Strength and Ductility
Mechanical Properties: Tensile strength ≥480 MPa, yield strength ≥176 MPa, elongation ≥40%, and hardness ≤200 HV, combining high strength with excellent plastic deformation capability.
Creep and Stress Corrosion Resistance: It maintains resistance to creep and stress corrosion cracking at elevated temperatures (e.g., 427-816°C), outperforming conventional stainless steels.
Machinability and Weldability
Ease of Fabrication: It can be formed via cold forging, drawing, bending, and other processes, with cold working hardening the material.
Welding-Friendly: No post-weld heat treatment is required. AWS E317L/ER317L filler or nickel-based welding materials containing chromium and molybdenum are recommended to match the base metal’s corrosion resistance.
