317 Stainless Steel: Enhanced Molybdenum for Severe Corrosion

 

What defines 317's chemical composition?​

It contains 18-20% chromium, 11-15% nickel, 3-4% molybdenum, and 0.08% max carbon. The higher molybdenum content compared to 316 (which has 2-3% molybdenum) enhances its resistance to pitting and crevice corrosion, especially in chloride-rich settings.​

 

How does 317 perform in corrosive environments?​

317 outperforms 316 in highly aggressive conditions, including sulfuric acid, phosphoric acid, and high-chloride solutions. It resists pitting and crevice corrosion better, making it suitable for chemical processing, waste treatment, and offshore applications.​

 

What are its mechanical properties and formability?​

317 has a tensile strength of around 515 MPa and good ductility, with elongation up to 40%. It's weldable and formable using standard techniques, though it work-hardens more than 304, requiring occasional annealing for complex shapes.​

 

How does 317 compare to 317L?​

317L is a low-carbon variant (≤0.03% carbon) of 317, designed to prevent intergranular corrosion after welding. 317 offers slightly better high-temperature strength due to its higher carbon, while 317L is preferred for welded structures in corrosive environments.​

 

What are 317's typical applications?​

Commonly used in chemical storage tanks, pharmaceutical processing equipment, and offshore oil rig components. It's also found in pulp and paper industry machinery and wastewater treatment systems where resistance to harsh chemicals is critical.