316L Austenitic Stainless Steel Coil Cold Rolled 2B 0.4mm-5mm Marine Grade Molybdenum 16Cr-10Ni-2Mo Corrosion Resistant

Our 316L (UNS S31603) austenitic stainless steel coil represents the premier choice for applications exposed to aggressive chloride-containing environments where standard 304 would be vulnerable to pitting and crevice corrosion. The defining metallurgical feature of 316L is the deliberate addition of 2.0-3.0% molybdenum, which dramatically enhances the stability and protective capability of the passive chromium oxide surface film, particularly in the presence of halide ions (chlorides, bromides) that aggressively attack standard stainless steels. With a Pitting Resistance Equivalent Number (PREN) exceeding 24 (Cr + 3.3Mo + 16N), 316L provides a substantially higher threshold against localized corrosion initiation compared to 304 (PREN ~18-20). The low carbon designation (max 0.03% C) eliminates the risk of intergranular chromium carbide precipitation during welding or thermal processing, maintaining full corrosion resistance in the as-welded condition without requiring post-weld solution annealing. This characteristic is critical for fabricated equipment such as pressure vessels, heat exchangers, and piping systems where in-situ post-weld heat treatment is impractical. Our 316L coils are manufactured through EAF melting, AOD refining for precise chemistry control, continuous casting, hot rolling, annealing and pickling, and final cold rolling with bright annealing in controlled atmosphere furnaces. The 2B finish provides a smooth uniform surface with Ra 0.1-0.5um. Full material certification to EN 10204 Type 3.1 is provided with every shipment, with optional 3.2 certification by independent inspection agency available upon request.

• Superior Pitting and Crevice Corrosion Resistance: The 2% molybdenum addition raises the critical pitting temperature (CPT) by 15-25C compared to 304 under equivalent chloride exposure. Standard ASTM G48 testing demonstrates pitting resistance in 6% FeCl3 solution at temperatures exceeding 20C, compared to 304 which pits at or below 0C in the same environment. This makes 316L the minimum acceptable stainless steel grade for marine atmospheric exposure, coastal architectural applications, chemical processing equipment handling moderate chloride concentrations, and pharmaceutical manufacturing where surfaces must withstand aggressive cleaning and sterilization chemicals including sodium hypochlorite and peracetic acid solutions.
• NACE MR0175 Compliance for Sour Service: 316L meets the stringent metallurgical requirements of NACE MR0175/ISO 15156 for sulfide stress cracking (SSC) resistance in H2S-containing oil and gas production environments. The controlled hardness (maximum 22 HRC in solution annealed condition), low carbon content, and optimized chemical composition ensure resistance to environmentally assisted cracking mechanisms in sour service conditions up to the material's specified temperature and H2S partial pressure limits.
• Excellent Weldability with Low Heat Input Sensitivity: The ultra-low carbon content (max 0.03%) ensures freedom from intergranular carbide precipitation during welding, even in heavy section welds with multiple passes and extended thermal exposure. The chromium depletion zone that forms along grain boundaries in standard 316 during welding does not develop in 316L, maintaining full intergranular corrosion resistance in the as-welded condition. All common fusion welding processes are applicable including GTAW, GMAW, SMAW, SAW, and FCAW.
• Pharmaceutical and Biotechnology Grade Compatibility: 316L is the industry-standard material of construction for pharmaceutical, biotechnology, and medical device manufacturing equipment per ASME BPE, USP Class VI, and EP 3.1.X requirements. The 2B surface finish with Ra below 0.5um meets surface finish specifications for product contact surfaces, while the molybdenum-enhanced corrosion resistance withstands CIP cycles using hot alkaline detergents, acid passivation solutions, and steam sterilization at 121-135C without pitting or surface degradation.
• High Temperature Mechanical Property Retention: 316L maintains useful mechanical properties at elevated temperatures significantly exceeding the limits of 304. The molybdenum addition contributes to improved creep resistance and stress rupture properties at temperatures up to 550C continuous service and 870C intermittent exposure. The minimum 0.2% proof stress at 200C is approximately 150 MPa, declining to ~120 MPa at 400C, providing sufficient design margins for pressure vessel applications operating at moderate elevated temperatures.
• Comprehensive Surface Finish Portfolio: Beyond the standard 2B cold rolled finish, our 316L coils are available in a complete range of surface finishes: BA (Bright Annealed) provides mirror-like reflectivity, No.4 (brushed/satin) with 180-240 grit directional polishing for architectural applications, HL (Hairline) offers continuous linear grain for large surface areas, Mirror 8K provides >95% reflectivity for premium decorative applications, and No.1 (HRAP) for structural and industrial applications where surface aesthetics are secondary.
• Verified Corrosion Performance Documentation: Beyond standard mill test certification, we offer a comprehensive suite of corrosion testing services to validate 316L performance. ASTM G48 Method A (ferric chloride pitting test), ASTM A262 Practice C (nitric acid/huey test for intergranular corrosion), ASTM G28 Method A (ferric sulfate-sulfuric acid test), and electrochemical testing per ASTM G61 (cyclic potentiodynamic polarization) are available to characterize pitting potential, repassivation potential, and critical crevice corrosion temperature for your specific application environment.

316L stainless steel coils are specified for the most demanding corrosion resistance applications where 304 would be inadequate. Primary applications include marine and offshore engineering (deck hardware, railing systems, fasteners, structural brackets, yacht fittings, offshore platform walkways and grating, desalination plant components), chemical and petrochemical processing (pressure vessels, storage tanks, heat exchangers, distillation columns, piping systems handling chlorinated hydrocarbons, organic acids, and halogenated compounds), pharmaceutical and biotechnology manufacturing (bioreactor vessels, chromatography columns, sterile piping systems, WFI storage and distribution, cleanroom structural components), food processing for aggressive media (citrus juice processing, vinegar production, soy sauce fermentation, dairy processing with chlorinated cleaning agents), pulp and paper industry (digester components, bleach plant equipment, chemical recovery boiler tubing), textile dyeing and finishing (dye bath vessels, bleaching range components), coastal architectural applications (exterior cladding within 5km of breaking surf, bridge expansion joint covers), and medical device manufacturing (surgical implant components, orthopedic fixation devices). The molybdenum content distinguishes 316L as the minimum acceptable grade whenever chlorides exceed 200 ppm at ambient temperature or whenever warm chloride solutions are encountered.

316L coils receive enhanced protective packaging with acid-free interleaving paper, heavy-duty VCI anti-corrosion paper with molybdate-based inhibitors specifically formulated for stainless steel, multi-layer UV-stabilized waterproof polyethylene film with heat-sealed seams, heavy-duty edge protection rings, and high-tensile steel strapping. Coils are mounted on ISPM 15 certified pallets or welded steel cradles. Container stowage uses rated timber dunnage, pneumatic dunnage bags, and grade-80 lashing chains. Each coil carries a weatherproof identification tag. Complete EN 10204 Type 3.1 certification is standard, with Type 3.2 independent inspection agency certification available. Pharmaceutical-grade 316L products include additional documentation covering surface finish certification, passivation records, and cleanroom packaging verification to support cGMP compliance.