310S Austenitic Stainless Steel Coil Cold Rolled 0.5mm-6mm 25Cr-20Ni High Temperature Furnace Grade SS Coil

Our 310S (UNS S31008) austenitic stainless steel coil is engineered for the most demanding high-temperature service conditions where standard 304/316 would rapidly succumb to oxidation, scaling, and creep deformation. With a nominal composition of 25% chromium and 20% nickel (substantially enriched compared to 304's 18Cr-8Ni), 310S provides exceptional oxidation resistance in air up to 1150C continuous service and 1035C intermittent service. The high chromium content promotes formation of a dense, adherent Cr2O3 scale that serves as an effective diffusion barrier against further oxidation, while elevated nickel ensures a fully austenitic microstructure resistant to sigma phase embrittlement during extended elevated temperature exposure. The low carbon designation (max 0.08%) minimizes carbide precipitation that could compromise ductility after thermal cycling. Our 310S coils are produced through EAF melting with AOD refining, continuous casting, hot rolling, solution annealing at 1040-1150C followed by rapid quenching, and cold rolling with intermediate annealing. The microstructure is fully austenitic with controlled grain size (ASTM 5-7) optimized for balanced creep strength and oxidation resistance. Every heat is verified by OES for composition and tensile tested at ambient and, upon request, elevated temperatures. Complete EN 10204 Type 3.1 certification and optional third-party inspection agency verification are standard.

• Exceptional High-Temperature Oxidation Resistance: With 25% chromium, 310S forms a highly protective Cr2O3 oxide scale that resists spallation during thermal cycling and maintains protective character to temperatures approaching 1150C. Isothermal oxidation testing (100-hour exposure in still air) demonstrates weight gain rates below 1 mg/cm2 at 1000C, compared to rapid breakaway oxidation in 304 above 900C. Essential for furnace components, radiant tubes, burner nozzles, and heat treatment fixtures.
• Superior Creep and Stress Rupture Strength: The high alloy content provides significantly better creep resistance than 304/316 above 600C. The 100,000-hour creep rupture strength at 700C is approximately 15-20 MPa for 310S, roughly 3-4 times higher than 304 at the same temperature. This creep performance makes 310S suitable for pressure-containing components operating in the creep range, including superheater and reheater tubing in power generation boilers.
• Resistance to Carburization and Nitriding: High chromium and nickel content provides superior resistance to carbon absorption (carburization) and nitrogen absorption (nitriding) from process atmospheres at elevated temperatures. The protective chromium oxide scale serves as a carbon diffusion barrier, while the nickel-rich matrix resists formation of embrittling carbide and nitride phases. Critical for heat treatment furnace components exposed to endothermic carburizing and ammonia-based nitriding atmospheres.
• Good Resistance to Thermal Fatigue: 310S demonstrates excellent resistance to thermal fatigue cracking under cyclic heating and cooling conditions encountered in batch-type furnaces, heat treatment fixtures, and intermittently operated combustion equipment. High ductility (min 40% elongation), lower thermal expansion than 304 (15.9 vs 17.2 um/m/C), and stable oxide scale enable 310S components to withstand thousands of thermal cycles without developing fatigue cracks.
• Proven Performance Across Multiple Industries: 310S has accumulated decades of successful service experience across thermal processing, power generation, petrochemical, and aerospace industries. This extensive track record provides engineering confidence in material selection, supported by comprehensive databases of mechanical properties, corrosion rates, and oxidation kinetics at elevated temperatures. ASME Section II Part D and EN 13445 include 310S in their allowable stress tables for elevated temperature design.
• Stable Austenitic Structure Without Sigma Embrittlement: The high nickel content (19-22%) maintains a fully austenitic structure that resists sigma phase formation, a hard brittle intermetallic compound that forms in ferrite-containing stainless steels during 550-900C exposure. While 310S can eventually form sigma after very long exposures (thousands of hours), the kinetics are substantially slower than in duplex or ferritic grades, providing a wider processing and service window.
• Good Weldability for Furnace Equipment Fabrication: 310S is weldable using GTAW, GMAW, and SMAW with matching filler metals (ER310/E310-16). The fully austenitic solidification mode eliminates hot cracking risk associated with ferrite-containing weld metals, but requires careful parameter control to avoid solidification cracking in highly restrained joints. Preheat is generally not required and post-weld heat treatment is unnecessary for most applications.

310S coils are specified for the most demanding high-temperature applications. Primary sectors include industrial furnace components (radiant tubes, muffles, retorts, burner nozzles, combustion chamber liners, conveyor belts), heat treatment equipment (annealing boxes, carburizing furnace fixtures, nitriding components, vacuum furnace hot zones), power generation (boiler superheater tube supports, burner fronts, ash hopper liners, flue gas expansion joints), petrochemical processing (ethylene cracking furnace tubes, steam reformer components, FCCU regenerator internals), incineration and thermal oxidation (grate components, combustion chambers, afterburner liners), and aerospace (jet engine combustion chamber components, afterburner flame holders). The combination of outstanding oxidation resistance, good creep strength, and proven long-term service performance has established 310S as the reference grade for applications operating continuously above 1000C in oxidizing atmospheres.

310S coils receive specialized packaging with acid-free interleaving paper, high-alloy-specific VCI anti-corrosion paper, heavy-duty waterproof polyethylene film with heat-sealed seams, high-tensile steel strapping, and edge protection rings. Coils on ISPM 15 pallets or steel cradles. Container stowage with timber blocking, air bags, and rated lashing chains. Complete EN 10204 Type 3.1 certification. Type 3.2 and elevated temperature tensile certification available on request.