AISI 316N is a nitrogen-strengthened, molybdenum-bearing austenitic stainless steel with excellent chloride corrosion resistance, while Nickel 600 is a nickel-based alloy for extreme high-temperature and highly corrosive environments, especially alkaline and reducing service. Where 316N may struggle, Nickel 600 offers better strength and stability, but at a higher cost. The selection is a classic cost-versus-performance decision.
Key Takeaways
316N: nitrogen solid-solution strengthening raises yield and creep resistance without losing corrosion resistance.
600: Ni ≥72%, resists high-temperature oxidation, carburization and caustic attack.
316N suits marine, food and general chemical service; 600 suits furnaces, reactors and nuclear parts.
Choose by temperature ceiling, media and budget.
What Is AISI 316N?
AISI 316N is a modified material based on standard 316 austenitic stainless steel with added nitrogen. Through nitrogen solid-solution strengthening it significantly improves strength, especially yield strength, and creep resistance without reducing corrosion resistance. While maintaining the chloride and pitting resistance of 316, it suits applications requiring both high structural strength and corrosion resistance: chemical pressure vessels, marine structures, high-strength fasteners and pressure-bearing equipment where reduced wall thickness saves cost.
What Is Nickel 600?
Nickel 600 (Inconel 600) is a nickel-chromium-iron solid-solution strengthened alloy with nickel 72% minimum, chromium 14-17% and iron 6-10%. It has excellent high-temperature corrosion resistance and oxidation resistance, and maintains good mechanical strength and plasticity below 700 °C, suiting nuclear reactors, aerospace engine components, petrochemical equipment and heat-treatment furnaces.
Chemical Composition
AISI 316N (UNS S31651): iron balance at about 60-65%, nickel 10.0-14.0%, chromium 16.0-18.0%, molybdenum 2.0-3.0%, nitrogen 0.10-0.16%, manganese up to 2.00%, silicon up to 1.00%, carbon up to 0.08%, phosphorus up to 0.045%, sulfur up to 0.030%. Nickel 600 (UNS N06600): iron 6.0-10.0%, nickel 72.0% minimum, chromium 14.0-17.0%, manganese up to 1.00%, silicon up to 0.50%, carbon up to 0.15%, phosphorus and sulfur up to 0.015%, copper up to 0.50%.
Physical Properties
316N (annealed): density 7.98 g/cm³, melting range about 1375-1400 °C, thermal expansion 16.0 x 10⁻⁶ /K, conductivity 16.3 W/(m·K), resistivity 0.74 μΩ·m, modulus 193 GPa, essentially non-magnetic. Nickel 600 (annealed): density 8.47 g/cm³, melting range 1354-1413 °C, expansion 13.3 x 10⁻⁶ /K, conductivity 14.9 W/(m·K), resistivity 1.03 μΩ·m, modulus 214 GPa, essentially non-magnetic.
Corrosion and Performance Comparison
316N offers good room-temperature strength and excellent corrosion resistance, but strength and corrosion resistance decrease at extremely high temperatures; the molybdenum addition gives superior chloride pitting and crevice resistance versus standard 304. Nickel 600 maintains strength at extreme temperatures that cause stainless failure, resists high-temperature oxidation, carburization and molten caustic soda, and prevents stress corrosion cracking. Best uses for 316N: marine finishing, food processing, medical implants, general chemical handling, bleaching solutions and the paper and textile industry. Best uses for 600: furnace components, heat exchangers, molten caustic service, nuclear reactors and stress corrosion cracking prevention.
Selection Guidance
For cost-effective marine, food or general chemical applications where temperatures stay moderate, choose 316N. For harsh high-temperature chemical processing, highly alkaline environments or nuclear duty, choose Nickel 600 despite the higher material and manufacturing cost.
Frequently Asked Questions
Q: What does nitrogen do in 316N?
Nitrogen solid-solution strengthening significantly raises yield strength and creep resistance without reducing corrosion resistance.
Q: Which alloy resists chloride pitting better?
316N, whose 2-3% molybdenum gives superior pitting and crevice resistance in chloride environments.
Q: Which alloy handles high-temperature oxidation?
Nickel 600, with strength retained at temperatures where stainless steel fails.
Q: Is Nickel 600 more expensive than 316N?
Yes, significantly, due to the 72% minimum nickel content.
Q: What are the UNS numbers?
AISI 316N is UNS S31651 and Nickel 600 is UNS N06600.
Q: Where is 316N used?
Chemical pressure vessels, marine structures, high-strength fasteners and pressure-bearing equipment.
