What Is HAYNES® HR-120® Alloy?
A Complete Material Guide for Engineers

What Is HAYNES® HR-120® Alloy?

HAYNES® HR-120® is a solid-solution-strengthened iron-nickel-chromium (Fe-Ni-Cr) heat-resistant alloy developed and trademarked by Haynes International, Inc., registered under the Unified Numbering System as UNS N08120 and designated 2.4854 under European DIN/EN standards.

Unlike conventional austenitic stainless steels (e.g., 310S) or fully nickel-base alloys (e.g., Inconel® 601 or Haynes® 230), HR-120 occupies a deliberate middle position. Its nickel content (~37%) delivers exceptional corrosion and creep resistance at elevated temperatures, while keeping raw-material cost well below pure Ni-base grades. The result is an alloy uniquely suited to the 900–1150°C operating band where neither stainless steels nor premium Ni-base grades offer the best cost-performance balance.

The alloy achieves its performance through precise additions of chromium (25%), nitrogen, tungsten, and niobium to strengthen the austenite matrix at elevated temperatures, plus aluminum and silicon to improve oxidation and sulfidation surface resistance.

Chemical Composition of HAYNES® HR-120® (UNS N08120)

The table below lists the full elemental range per ASTM B564 / ASME SB-564. Verifying these values on mill test reports is essential to confirm alloy identity, particularly for the distinguishing micro-alloying additions (W, Nb, N).

★ Highlighted elements (W, Nb, N) distinguish HR-120 from older Fe-Ni-Cr grades like Alloy 800H. Always verify on MTR.

Why Tungsten, Niobium, and Nitrogen?

Tungsten and niobium partition to the austenite lattice and grain boundaries, resisting dislocation motion above 900°C where carbon-only strengthening becomes ineffective. Nitrogen improves pitting resistance during ambient-temperature handling, cleaning, and storage.

Mechanical Properties of HAYNES® HR-120® (UNS N08120)

All values represent solution-annealed (1177–1210°C) forged material unless stated otherwise.

Room-Temperature Properties

Elevated-Temperature Tensile Strength (Typical Forged Bar)

High-Temperature Performance of HAYNES® HR-120®

The defining advantage of HR-120 versus competing Fe-Ni-Cr grades is its stress-rupture performance above 900°C, enabled by tungsten and niobium additions that retard dislocation creep relative to Alloy 800H or 310S.

100-Hour Rupture Stress Comparison (Typical Values)

At 980°C, HR-120 carries 73% more sustained stress than Alloy 800H for equivalent 100-hour rupture life — directly enabling thinner walls, lower mass, and longer replacement intervals in furnace fixtures and radiant tubes.

Mean Thermal Expansion Coefficient

Corrosion, Oxidation, Carburization & Sulfidation Resistance

HR-120 was designed for environments presenting multiple simultaneous corrosion modes — oxidation, carburization, and sulfidation — that defeat most single-purpose alloys. The 25% chromium content forms a dense, self-healing Cr₂O₃ scale, reinforced by aluminum and silicon above 900°C.

Oxidation Resistance

In cyclic oxidation testing at 1010°C (fan-cooled every 30 minutes for 500+ hours), HR-120 showed metal loss comparable to Alloy 800H and significantly better than 310SS, while offering superior mechanical strength at those temperatures.

Carburization Resistance

In 982°C carburization testing in carbonaceous gas streams, HR-120 demonstrated very low carbon absorption — substantially below 800H and Alloy 330 under equivalent conditions. Critical for ethylene cracking furnace components where carburization is the primary degradation mechanism.

Sulfidation Resistance

The chromium and aluminum content provides good resistance to mixed oxidizing/sulfidizing atmospheres typical of waste incinerators, waste-to-energy boilers, and certain petrochemical environments. In strongly reducing, low-O₂ sulfidizing conditions, all Fe-Ni-Cr alloys including HR-120 are susceptible to accelerated attack — site-specific coupon testing is recommended.

Aqueous Corrosion Resistance

At ambient temperatures, the nitrogen addition provides measurable pitting and crevice corrosion resistance for standard industrial handling. HR-120 is not optimized for highly reducing or halide-rich aqueous service.

HAYNES® HR-120® vs. Competing Alloys

Selecting a high-temperature alloy involves tradeoffs between performance, cost, availability, and fabricability. The cards below compare HR-120 against the most commonly evaluated alternatives.

Forging & Heat Treatment of HAYNES® HR-120® (UNS N08120)

HR-120 can be processed by conventional hot- and cold-working methods, though it requires tighter temperature control and higher press loads than standard austenitic stainless steels due to its higher work-hardening rate.

Hot Working Parameters

Jiangsu Liangyi's facility is equipped with 0.75t, 1t, 3t, 6t, and 9t electro-hydraulic forging hammers and 2,000t, 4,000t, and 6,000t hydraulic forging presses, with 3m and 6m ring-rolling machines providing the press force required for HR-120's higher work-hardening rate. Our full range of HR-120 open die forgings and seamless rolled rings — from 30 kg discs to 30-ton shafts and rings up to 6,000 mm OD — is available with EN10204-3.1 documentation as standard.

Solution Annealing — Mandatory Step

All HR-120 forged components must be solution annealed after forging to dissolve carbide precipitates and restore full ductility. Skipping this step produces a sensitized microstructure prone to intergranular corrosion and premature creep failure in service.

Open Die Forging vs. Seamless Rolled Rings

• A
  Open Die Forging

  Suited to discs, shafts, hubs, blocks, and custom-profile components from 30 kg to 30,000 kg. Repeated press strokes and die rotations produce refined, directional grain flow optimizing fatigue and creep resistance along the primary stress axis.
• B
  Seamless Rolled Rings

  Preferred for flanges, seal rings, turbine rings, bearing races, and gear blanks. Circumferential grain flow aligned to the ring geometry delivers superior hoop-stress resistance. Jiangsu Liangyi produces HR-120 rolled rings from 100mm to 6,000mm OD.

Welding Recommendations

HAYNES® HR-120® is readily weldable by GTAW (TIG), GMAW (MIG), SMAW, and SAW processes. Recommended filler material: HAYNES® 556® filler wire (registered trademark of Haynes International, Inc.) or Hastelloy® X as an alternative. Post-weld solution annealing at 1177–1210°C is strongly recommended for components operating above 700°C.

Industrial Applications of HAYNES® HR-120® Forgings

The combination of high-temperature strength, multi-mode corrosion resistance, and competitive cost makes HR-120 the material of choice across a wide range of thermally demanding industries. Below are the primary sectors served by custom UNS N08120 forged components.

Applicable Standards & Certifications

Third-party inspection bodies commonly used by our clients (buyers arrange and pay independently): TÜV · Bureau Veritas (BV) · DNV · Germanischer Lloyd (GL) · ABS · Lloyd's Register · RINA · RMRS. Jiangsu Liangyi will cooperate fully with any accredited inspection body your project requires.

NDT Capabilities Available In-House

Visual (VT) · Dimensional Inspection · Ultrasonic Testing (UT per ASTM A388 / EN10228) · Dye Penetrant Testing (PT) · Magnetic Particle Inspection (MPI) · Metallographic Examination · Hardness Testing (Brinell / Vickers) · Chemical Analysis · Mechanical Testing (Tensile, Yield, Elongation, Charpy Impact)

FAQ: HAYNES® HR-120® (UNS N08120)