⚡ Quick Specs: Nitronic 50
What Is Nitronic 50?
Nitronic 50 — known as UNS S20910, EN 1.3964, and originally as XM-19 — is a nitrogen-strengthened austenitic stainless steel developed by Armco (now AK Steel / Outokumpu) in the 1960s. By adding roughly 0.25% nitrogen and increasing manganese to ~5%, the alloy achieves a remarkable combination: about twice the yield strength of standard 316L, excellent chloride stress-corrosion cracking resistance, and full non-magnetic behavior in the annealed condition.
For designers, Nitronic 50 is the workhorse material that bridges the gap between standard 300-series stainless and full nickel-base superalloys. It costs less than Inconel or Hastelloy, weighs less than 316L for the same strength, and lasts years longer in marine and chemical service. As an established Nitronic 50 supplier and manufacturer, Hangbo Alloy Group supplies the grade in bar, plate, sheet, wire, and forgings to marine, aerospace, oil & gas, and chemical customers worldwide.
Chemical Composition
Nominal composition of Nitronic 50 per ASTM A276 / A479 is shown below. All values in weight percent (wt%).
| Element | Content (wt%) |
|---|---|
| C | ≤ 0.06 |
| Si | ≤ 1.00 |
| Mn | 4.0 – 6.0 |
| P | ≤ 0.045 |
| S | ≤ 0.030 |
| Cr | 20.5 – 23.5 |
| Ni | 11.5 – 13.5 |
| Mo | 1.5 – 3.0 |
| N | 0.20 – 0.40 |
| Nb | 0.10 – 0.30 |
| V | 0.10 – 0.30 |
| Fe | Balance |
The 0.2–0.4% nitrogen content is the heart of Nitronic 50. Nitrogen is a strong austenite stabilizer and an extremely potent solid-solution strengthener — every 0.10% nitrogen adds roughly 60–80 MPa to yield strength. The 4–6% manganese further stabilizes the austenite and improves nitrogen solubility, allowing the alloy to maintain a fully austenitic structure without forming strain-induced martensite during cold work.
Physical Properties
| Property | Value |
|---|---|
| Density | 7.88 g/cm³ (0.285 lb/in³) |
| Melting Range | 1370 – 1425 °C (2500 – 2600 °F) |
| Specific Heat (20 °C) | ~ 500 J/kg·K |
| Thermal Conductivity (20 °C) | ~ 14 W/m·K |
| Electrical Resistivity (20 °C) | ~ 0.82 µΩ·m |
| Young's Modulus | ~ 200 GPa |
| Magnetic Permeability (Ann.) | ~ 1.01 (fully non-magnetic) |
| Mean CTE (20–200 °C) | ~ 16.0 × 10⁻⁶ /K |
Mechanical Properties (Room Temperature, Annealed)
| Property | Annealed Bar | High-Strength (Cold Worked) |
|---|---|---|
| Tensile Strength (Rm) | ≥ 690 MPa (100 ksi) | ≥ 1000 MPa (145 ksi) |
| Yield Strength (Rp0.2) | ≥ 380 MPa (55 ksi) | ≥ 900 MPa (130 ksi) |
| Elongation (A%) | ≥ 30% | ≥ 15% |
| Hardness | ≤ 293 HB | ≤ 350 HB |
| Reduction of Area | ≥ 50% | ≥ 40% |
| Condition | Annealed 1065 °C, WQ | Cold-worked (varies) |
Note the 380 MPa minimum yield — about 2.3× the 170 MPa typical of 316L. The alloy also retains useful ductility (≥30% elongation) and toughness, allowing cold heading, swaging, and forming operations that would be impossible with duplex or martensitic alternatives of similar strength.
Corrosion Resistance
Nitronic 50 was designed to outperform 316L in chloride-rich, sour, and marine environments. Its nitrogen-stabilized austenite and higher Mo (2% vs 2% in 316L, but with N strengthening the passive film) give it meaningfully better pitting, crevice, and SCC resistance while keeping it in the stainless family.
- Chloride SCC: Nitronic 50 is immune to chloride SCC at temperatures that would crack 316L — a critical advantage for hot chloride service and sour oil & gas.
- Pitting Resistance: PREN ≈ 30 (Cr + 3.3·Mo + 16·N) — comparable to 6Mo super-austenitic grades in low-chloride service, but lower than Alloy 926 in hot concentrated chlorides.
- Sulfuric Acid: Good resistance below 40% concentration at moderate temperatures, particularly in oxidizing conditions.
- Nitric Acid: Excellent resistance up to 70% concentration; widely used in nitric acid coolers, condensers, and reboilers.
- Sour Service: Qualified under NACE MR0175 / ISO 15156 to specific H₂S partial-pressure limits.
Cryogenic Performance
Unlike ferritic and duplex stainless, Nitronic 50 is fully austenitic and shows no ductile-to-brittle transition. Charpy V-notch impact toughness remains above 200 J down to –196 °C (–320 °F). This makes the alloy a proven specification for LNG piping, valve bodies, and downhole tooling exposed to arctic and sub-zero conditions.
Applications
The unique strength + corrosion combination makes Nitronic 50 the material of choice for components that 316L is too weak for and Inconel is too expensive for.
| Application Area | Typical Components & Notes |
|---|---|
| Marine Engineering | Pump shafts, valve stems, propeller shafts, non-magnetic fasteners, naval mine-countermeasure hardware |
| Aerospace | Actuator pins, landing gear, fasteners, flap tracks — the alloy is on the QPL for several airframers |
| Oil & Gas (Downhole) | Packers, hangers, safety valve components, and tooling exposed to H₂S / CO₂ / chlorides |
| Chemical Processing | Nitric acid coolers, sulfuric acid piping, urea reactor internals, organic acid equipment |
| Pulp & Paper | Bleach plant washers, chlorination-stage equipment, paper machine parts |
| Cryogenic / LNG | LNG piping, valve bodies, and pump internals down to –196 °C |
| Power Generation | Nuclear valve and pump internals, MSR piping, fossil-fuel boiler tube hangers |
| Pharmaceutical & Food | Mixer shafts, agitators, and CIP system hardware where non-magnetic high strength is needed |
Available Product Forms
| Product Form | Typical Dimensions |
|---|---|
| Round Bars (ASTM A276 / A479) | φ 6 – φ 350 mm, hot-rolled, cold-drawn, forged |
| Plates & Sheets (ASTM A240) | Thickness 0.5 – 60 mm, width up to 2000 mm |
| Wire (ASTM A580) | φ 0.5 – φ 10 mm, cold-drawn, spring temper available |
| Hex & Square Bars | Custom sizes for fastener and valve-stem production |
| Forgings (ASTM A182 / AMS 5764) | Discs, rings, shafts, custom shapes |
| Welding Consumables | AWS A5.4 E209 / A5.9 ER209, plus ERNiCrMo-3 for high-corrosion joints |
Related Standards & Specifications
| Standard | Product Scope |
|---|---|
| ASTM A276 / A479 | Bar & shapes (pressure-vessel grade) |
| ASTM A240 / ASME SA-240 | Plate, sheet & strip |
| ASTM A580 | Wire |
| ASTM A182 | Forged flanges, fittings, valves |
| AMS 5764 | Bar & forging (aerospace) |
| AMS 5765 | Plate & sheet (aerospace) |
| ASME SA-479 | Bar for boiler & pressure vessels |
| NACE MR0175 / ISO 15156 | Sour-service environments |
| DIN / W.Nr. | 1.3964 |
Frequently Asked Questions (FAQ)
1. What is Nitronic 50?
Nitronic 50 (UNS S20910 / W.Nr. 1.3964, also known as XM-19) is a nitrogen-strengthened austenitic stainless steel. It delivers roughly twice the yield strength of standard 316L while retaining excellent corrosion resistance — particularly to chloride pitting, crevice, and stress-corrosion cracking. As a leading Nitronic 50 manufacturer and supplier, Hangbo Alloy Group supplies the grade in bar, plate, sheet, wire, and forgings for marine, aerospace, chemical, and oil & gas applications.
2. What is the chemical composition of Nitronic 50?
Nominal Nitronic 50 composition (wt%): C ≤0.06, Si ≤1.00, Mn 4.0–6.0, P ≤0.045, S ≤0.030, Cr 20.5–23.5, Ni 11.5–13.5, Mo 1.5–3.0, N 0.20–0.40, Nb 0.10–0.30, V 0.10–0.30, Fe balance. The ~0.25% nitrogen addition and manganese stabilization are what give Nitronic 50 its exceptional combination of strength and corrosion resistance.
3. What is the density and melting point of Nitronic 50?
Nitronic 50 has a density of approximately 7.88 g/cm³ (0.285 lb/in³) and a melting range of about 1370–1425 °C (2500–2600 °F). The density is slightly lower than 316L because of the high Mn and N content.
4. What are the mechanical properties of Nitronic 50?
Annealed bar (room temperature): tensile strength ≥690 MPa (100 ksi), 0.2% yield strength ≥380 MPa (55 ksi), elongation ≥30%, hardness ≤293 HB. Annealed at 1065 °C and water-quenched, the alloy reaches 2× the yield strength of 316L while maintaining 35–40% elongation. Higher strengths (≥1000 MPa tensile) are achievable by cold working.
5. How does Nitronic 50 compare to 316L?
Both are austenitic, non-magnetic in the annealed state, and weldable, but Nitronic 50 has roughly 2× the yield strength of 316L, ~3× the Mo content, and nitrogen strengthening. Pitting and crevice corrosion resistance are clearly better, and chloride SCC resistance is far superior — 316L routinely suffers SCC in warm chloride brines, while Nitronic 50 resists it. For high-stress marine hardware, fasteners, pump shafts, and valve stems, Nitronic 50 is the lighter, stronger, longer-lasting substitute for 316L.
6. What is the maximum service temperature of Nitronic 50?
Nitronic 50 retains useful mechanical strength up to about 870 °C (1600 °F) for intermittent service and ~600 °C (1110 °F) for continuous service. For cryogenic applications it is exceptional: impact toughness is retained down to –196 °C (–320 °F) and the alloy is fully austenitic, so no ductile-to-brittle transition occurs.
7. Is Nitronic 50 magnetic?
In the annealed condition Nitronic 50 is essentially non-magnetic (permeability ~1.01). Cold working increases magnetic response slightly, but it remains well below the values for duplex or martensitic grades. For non-magnetic instrumentation, marine mine-countermeasure, and MRI-grade hardware, Nitronic 50 is a proven specification.
8. Can Nitronic 50 be welded?
Yes. Nitronic 50 is readily welded by GTAW, GMAW, and SMAW. Matching filler metal is AWS A5.4 E209 or AWS A5.9 ER209. For highest corrosion performance, a nickel-rich filler such as ERNiCrMo-3 (Inconel 625) is sometimes used. No preheat is required; interpass temperature should be limited to about 150 °C. The nitrogen content keeps the alloy fully austenitic, eliminating concerns about weld sensitization.
9. What standards apply to Nitronic 50?
Nitronic 50 is produced under ASTM A276 (bar), A479 (bar for boilers/pressure vessels), A240 (plate/sheet), A580 (wire), A182 (forged flanges/fittings), AMS 5764 (bar/ forging), AMS 5765 (plate/sheet), and the corresponding ASME SA equivalents. It is also qualified under NACE MR0175 / ISO 15156 for sour service up to defined limits.
10. What are the typical applications of Nitronic 50?
Primary applications: (1) Marine — pump shafts, valve stems, propeller shafts, fasteners, non-magnetic hardware; (2) Aerospace — actuator pins, landing gear components, fasteners; (3) Oil & gas — downhole tooling, packers, hangers, sour-service components; (4) Chemical — sulfuric and nitric acid service, urea equipment; (5) Pulp & paper; (6) Cryogenic — LNG equipment, down to –196 °C; (7) Power generation — nuclear and fossil-fuel valve and pump internals.
11. What is the price and lead time for Nitronic 50?
Nitronic 50 is a premium nitrogen-strengthened stainless. Indicative pricing: bars $15–25/kg, plates $20–35/kg, forgings $25–40/kg. Lead time is typically 6–10 weeks for mill orders. Hangbo Alloy Group maintains inventory of common bar and plate sizes for fast shipment. MOQ: 100 kg for stock items, 300 kg for custom specs. Contact hangbo@nickel-alloy.com for current pricing.
12. What is the difference between Nitronic 50 and Nitronic 60?
Nitronic 50 (UNS S20910) is a nitrogen-strengthened austenitic stainless for strength + corrosion resistance. Nitronic 60 (UNS S21800) is a silicon-and-nitrogen modified austenitic stainless optimized primarily for galling and wear resistance; it sacrifices some corrosion performance for exceptional metal-to-metal wear behavior. Choose Nitronic 50 when strength, chloride SCC resistance, and general corrosion dominate the design; choose Nitronic 60 for valve seats, wear plates, pins, and bushings where galling is the limiting factor.
Need Nitronic 50 for Your Project?
Hangbo Alloy Group is a trusted global manufacturer and supplier of Nitronic 50 (UNS S20910 / 1.3964) in bar, plate, sheet, wire, and forgings. Mill test certificates to EN 10204 3.1, full traceability, and competitive pricing on every order.