Alloy 556 (UNS R30556) is an iron-nickel-chromium-cobalt alloy specifically formulated to resist multiple forms of high-temperature corrosion simultaneously. Unlike conventional alloys optimized for single degradation mechanisms, this material provides balanced resistance to sulfidation, carburization, chlorination, and oxidation while maintaining excellent high-temperature strength and fabricability .
1. Product Specifications & Physical DataZYTC Alloy supplies UNS R30556 in mill forms suitable for waste processing, chemical recovery, and industrial heating applications requiring verified corrosion resistance in aggressive combustion environments. Available Forms: Plate, sheet, strip, bar, billet, wire, welding products, pipe, tube, and forgings . Specifications: ASTM B435 (plate/sheet/strip), B572 (rod), B619/B622/B626 (pipe/tube), AMS 5831 (wire), UNS R30556 .
| Chemical Composition (Weight %) | Haynes® 556 Specification |
|---|
| Iron (Fe) | Balance (approx. 31% nominal) | | Chromium (Cr) | 21.0 - 23.0 | | Nickel (Ni) | 19.0 - 22.5 | | Cobalt (Co) | 16.0 - 21.0 | | Molybdenum (Mo) | 2.5 - 4.0 | | Tungsten (W) | 2.0 - 3.5 | | Tantalum (Ta) | 0.30 - 1.25 | | Nitrogen (N) | 0.10 - 0.30 | | Manganese (Mn) | 0.50 - 2.0 | | Silicon (Si) | 0.80 max. | | Aluminum (Al) | 0.50 max. | | Carbon (C) | 0.05 - 0.15 | | Lanthanum (La) | 0.005 - 0.10 | | Zirconium (Zr) | 0.005 - 0.15 | | Boron (B) | 0.02 max. |
| Physical Properties | Metric | Imperial |
|---|
| Density | 8.23 g/cm³ | 0.297 lb/in³ | | Melting Range | 1330 - 1415°C | 2425 - 2580°F | | Modulus of Elasticity (RT) | 206 GPa | 29.7 × 10⁶ psi | | Thermal Conductivity (RT) | 11.1 W/m·K | 77 BTU·in/hr·ft²·°F |
| Mechanical Properties (Annealed Plate) | Temperature | Metric | Imperial |
|---|
| Tensile Strength | RT | 805 MPa | 116 ksi | | Yield Strength (0.2% offset) | RT | 375 MPa | 55 ksi | | Elongation | RT | 51% | 51% | | Tensile Strength | 760°C (1400°F) | 475 MPa | 69 ksi | | Yield Strength | 760°C (1400°F) | 200 MPa | 29 ksi | | Elongation | 760°C (1400°F) | 53% | 53% |
2. Fabrication & Material ComparisonHaynes® 556 nickel alloy offers good fabricability with proper techniques, making it practical for complex fabricated assemblies. Heat Treatment: Supplied in solution-annealed condition [2150°F (1175°C) with rapid cooling or water quench]. Heat treatment below solution temperature may cause secondary phase precipitation and should be avoided . Forming: Good hot and cold workability. Hot working requires holding at 1175°C (2150°F) to bring entire piece to temperature. Cold forming readily accomplished due to good ductility; anneal after working to restore properties . Welding: Excellent weldability using GTAW, GMAW, SMAW, and resistance welding. Matching filler metal (ERNiCrMo-3 type or specific 556 composition) recommended for corrosion resistance . Machining: Responds to conventional methods for high-temperature alloys. Carbide tooling recommended with positive rake angles; low cutting speeds and high feed rates reduce work hardening . Material Comparison : vs. 310 Stainless: Superior resistance to sulfidation, carburization, and chlorination; significantly higher high-temperature strength. vs. Alloy 800H: Dramatically better sulfidation resistance (23.2 mils affected vs. 2.0 mils at 980°C); preferred for sulfur-bearing environments. vs. Alloy 600/601: Outperforms in mixed corrosive environments; 556 remains intact where 600/601 are consumed or perforated in sulfidation testing.
3. Applications Waste Processing: Municipal and industrial waste incinerator components (superheater tubing, structural members, air nozzles) Metallurgical Processing: Hot-dip galvanizing hardware (chains, hooks, baskets, thermocouple sheaths), high-speed furnace fans, brazing fixtures Chemical Processing: Rotary calciners, carbon regenerators, high-sulfur petroleum feedstock equipment Power Generation: Burner buckets, fluidized bed combustor internals, heat exchangers Aerospace: Non-rotating gas turbine components (combustors, transition ducts) burning low-grade fuels Industrial Heating: Recuperators, kiln components, diesel engine air preheaters, coil annealing furnace covers
Contact ZYTC Alloy for certified Alloy 556 (UNS R30556) materials with complete traceability, technical datasheets, and competitive pricing on standard sizes or custom-fabricated components. Email:daisy@zytcsteel.com WhatsApp/WeChat: +86 17335753350 |
