Stainless Steel-316/316L

316L is an ultra-low carbon (C ≤ 0.03%), molybdenum-containing (Mo ≈ 2–3%) austenitic stainless steel belonging to the AISI 300 series. The “L” stands for “Low Carbon,” designed to prevent intergranular corrosion caused by chromium carbide precipitation during welding or high-temperature service.
It is a low-carbon modification of grade 316, offering significantly improved weldability and corrosion resistance while maintaining good strength and formability.

Excellent Corrosion Resistance

•  Due to the addition of 2–3% molybdenum (Mo), 316L exhibits superior resistance to pitting and crevice corrosion in chloride-containing environments (e.g., seawater, salt spray, bleach).
• Offers better resistance to reducing acids (e.g., dilute sulfuric, phosphoric, acetic acid) than 304/304L.
• Pitting Resistance Equivalent Number (PREN) typically ranges from 24 to 30, calculated as: PREN = %Cr + 3.3×%Mo + 16×%N.
  Excellent Weldability
  Preheating or post-weld heat treatment is generally not required (except for thickness >25 mm or extremely low ambient temperatures).
•  Matching filler metals (e.g., ER316L, E316L-16) are recommended to maintain corrosion resistance.
•  Post-weld pickling/passivation is not mandatory but highly recommended to optimize surface corrosion resistance.

Good Mechanical & Physical Properties

Non-magnetic in annealed condition (slight magnetism may develop after cold working)
Low thermal conductivity (~16 W/m·K), relatively high thermal expansion coefficient (16×10⁻⁶/K)
Cannot be hardened by heat treatment; only strengthened by cold working

Machinability & Surface Finishing

•  Poor machinability compared to carbon steel; carbide tools, low cutting speeds, and ample coolant are recommended.
•  Compatible with polishing, sandblasting, electropolishing (EP), and passivation.
• Electropolishing significantly enhances surface smoothness and corrosion resistance, commonly used in pharmaceutical and semiconductor industries.