ASTM B393 R04210 Niobium Fittings – Commercial-Grade Pure Niobium, Plate-Formed
What are ASTM B393 R04210 niobium fittings? They are caps, stub ends, large-bore and eccentric reducers, segmented elbows, headers and other fabricated fittings made from ASTM B393 sheet and plate in UNS R04210. R04210 is commercial-grade unalloyed niobium (ASTM Type 2). It is pure niobium, not a niobium alloy, and it costs less than reactor-grade R04200 because its impurity limits are slightly wider.
Note on specifications: ASTM B393 covers niobium and niobium-alloy strip, sheet and plate. Fittings formed or fabricated from that plate carry its grade, chemistry and test requirements. Butt-weld elbows and tees in smaller sizes are formed from ASTM B394 R04210 tube, and socket-weld and threaded fittings are machined from B392 bar.
R04210 Plate-Formed Fittings – Quick Facts
- Grade: UNS R04210, unalloyed niobium, commercial grade (Type 2)
- Raw material: ASTM B393 sheet (0.13–4.76 mm) and plate (over 4.76 mm)
- Fitting types: caps, stub ends, large-bore and eccentric reducers, segmented elbows, tees and headers, flanged nozzles
- Joining: TIG or electron-beam welding in high-purity argon or vacuum
- Condition: annealed, pickled and clean
- Certificate: EN 10204 3.1 with interstitial (C, O, N, H) analysis
ASC LLP, Mumbai, supplies R04210 fittings with matching plate, tube and flanges. For reactor-grade material see R04200 pure niobium fittings; browse all niobium fittings.
Properties of R04210 Niobium
- Corrosion resistance: excellent in hydrochloric, nitric and dilute sulphuric acid, most organic acids, many chloride solutions and liquid metals.
- Ductility: very ductile and easy to form, spin and deep-draw – ideal for plate-formed fittings.
- Weldability: weldable by TIG or EB in an inert or vacuum atmosphere.
- Moderate strength: pure niobium is soft – for higher strength use Nb-1Zr (R04251 / R04261).
- Lower cost than reactor grade: same minimum strength as R04200, with wider oxygen and tantalum limits.
Where Niobium Works – and Where It Doesn’t
- Use for: HCl, HNO₃, dilute H₂SO₄, acetic and other organic acids, bromine and chlorine chemistry, liquid sodium and lithium.
- Avoid: hydrofluoric acid and fluorides, hot concentrated sulphuric acid, strong hot alkalis, and conditions that charge hydrogen (galvanic contact with active metals).
- Temperature: niobium oxidises rapidly in air above about 400 °C – high-temperature service must be in vacuum, inert gas or liquid metal.
Plate-Formed R04210 Fitting Types
| Fitting type | Plate-forming / fabrication route |
| Caps | Deep-drawn or spun from B393 sheet / plate |
| Stub ends | Formed from plate or machined from plate rings |
| Large-bore and eccentric reducers | Rolled cone from plate, longitudinal weld |
| Segmented (mitred) elbows | Rolled and welded segments from plate |
| Tees, laterals & headers | Fabricated from rolled plate with welded branches |
| Flanged nozzles & transitions | Fabricated to drawing from plate |
Sizes to drawing – including large bores not available as tube.
Mechanical Properties – ASTM B393
| Grade (sheet / plate, annealed) | Tensile strength (min) | 0.2% yield strength (min) | Elongation (min) |
| R04200 / R04210 (pure Nb) | 125 MPa (18 ksi) | 73 MPa (10.5 ksi) | 20% |
| R04251 / R04261 (Nb-1Zr) | 195 MPa (28 ksi) | 125 MPa (18 ksi) | 20% |
Minimum tensile requirements for annealed sheet and plate per ASTM B393.
R04210 Plate-Formed Fittings Specifications
| Item | Details |
| Product | R04210 pure niobium fittings formed or fabricated from sheet and plate |
| Material standard | ASTM B393 (strip, sheet, plate) |
| Sheet thickness | 0.005 – 0.1875 in (0.13 – 4.76 mm) |
| Plate thickness | Over 0.1875 in (4.76 mm) |
| Sizes | To drawing |
| Welding | TIG / EB in argon chamber or vacuum |
| Testing | Chemical incl. interstitials, dimensional, visual, dye penetrant; radiography of seams on request |
| Certificate | EN 10204 3.1; third-party inspection on request |
R04210 Chemical Composition (ASTM B393)
| Element (max %) | R04210 – Type 2 (commercial grade) | R04200 – Type 1 (reactor grade) |
| Oxygen (O) | 0.025 | 0.015 |
| Carbon (C) | 0.01 | 0.01 |
| Nitrogen (N) | 0.01 | 0.01 |
| Hydrogen (H) | 0.0015 | 0.0015 |
| Tantalum (Ta) | 0.3 | 0.1 |
| Tungsten (W) | 0.05 | 0.03 |
| Molybdenum (Mo) | 0.020 | 0.010 |
| Zirconium (Zr) | 0.02 | 0.02 |
| Titanium (Ti) | 0.03 | 0.02 |
| Hafnium (Hf) | 0.02 | 0.02 |
| Iron (Fe) | 0.01 | 0.005 |
| Silicon (Si) | 0.005 | 0.005 |
| Nickel (Ni) | 0.005 | 0.005 |
| Niobium (Nb) | Remainder | Remainder |
R04210 allows more oxygen and tantalum than reactor-grade R04200, which makes it the economical choice for chemical and industrial service.
Physical Properties of Niobium
| Property | Value (approx.) |
| Density | 8.57 g/cm³ |
| Melting point | ≈ 2,477 °C (4,491 °F) |
| Crystal structure | Body-centred cubic |
| Coefficient of thermal expansion | ≈ 7.3 µm/m·°C (20–100 °C) |
| Thermal conductivity | ≈ 53 W/m·K |
| Magnetic | Non-magnetic |
Applications of R04210 Niobium Fittings
| Industry | Applications of R04210 plate-formed fittings |
| Chemical processing | Large-bore acid lines, headers and vessel nozzles in HCl and nitric service |
| Acid recovery & pickling | Reducers, caps and manifolds for acid recovery units |
| Vacuum furnaces | Hot-zone shields, retort parts and fabricated connections (vacuum or inert gas) |
| Industrial equipment | Linings, transitions and fabricated parts where pure niobium is specified |
Pure niobium is not used for jet-engine parts, nuclear fuel cladding or implants in these forms; superconducting magnets use Nb-Ti or Nb₃Sn wire.
Our Pure Niobium Fittings Range
| Page | What it covers |
| R04200 pure niobium fittings | Reactor-grade pure niobium fittings – main page |
| R04210 fittings from tube | Butt-weld elbows, tees and reducers formed from ASTM B394 tube |
| This page | R04210 caps, stub ends and fabricated fittings from ASTM B393 plate |
| Nb-1Zr niobium fittings | Higher-strength Nb-1Zr (R04251 / R04261) |
Why Buy R04210 Fittings from ASC LLP?
- Correct grade: R04210 plate to ASTM B393 with 3.1 certificates showing oxygen, tantalum and other interstitials.
- Plate, tube or bar routes: plate-formed, tube-formed and machined fittings from one supplier.
- Matching parts: R04210 flanges, R04210 fasteners and B393 R04210 plates.
- Drawings and one-off parts welcome, with clean export packing.
Send drawing, thickness and quantity to sales@amardeepsteel.com or call 022-67439130.
Frequently Asked Questions – ASTM B393 R04210 Niobium Fittings
What is R04210 niobium?
UNS R04210 is commercial-grade unalloyed niobium (ASTM Type 2). It has the same minimum strength as reactor-grade R04200 but allows more oxygen (0.025% max) and tantalum (0.3% max), so it costs less.
What does ASTM B393 cover?
ASTM B393 covers niobium and niobium-alloy strip, sheet and plate in grades R04200, R04210, R04251 and R04261. Fittings formed or fabricated from B393 plate carry its grade and test requirements.
What are the mechanical properties of R04210 sheet and plate?
ASTM B393 requires annealed pure niobium sheet and plate to have a minimum tensile strength of 125 MPa (18 ksi), yield strength of 73 MPa (10.5 ksi) and elongation of 20%.
What is the difference between R04200 and R04210?
Both are pure niobium. R04200 (reactor grade) has tighter limits on oxygen, tantalum, tungsten and molybdenum; R04210 (commercial grade) allows slightly more impurities and is used where nuclear-grade purity is not required.
Which acids is niobium resistant to?
Niobium resists hydrochloric, nitric and dilute sulphuric acid, most organic acids and many chloride solutions. It is attacked by hydrofluoric acid, hot concentrated sulphuric acid and strong hot alkalis.
Global Reach
ASC LLP supplies niobium, tantalum and other refractory-metal products to chemical, research and high-temperature industries worldwide, with secure packing and full documentation. Buyers in the USA, Europe, the Middle East and Asia rely on our ASTM B393 R04210 niobium fittings for certified material and traceability.
Countries We Export To
UNITED STATES, EUROPE, UK, UAE, SAUDI ARABIA, OMAN, KUWAIT, JORDAN, QATAR, INDONESIA, MALAYSIA, BRAZIL, SPAIN, ITALY, FRANCE, GERMANY, BAHRAIN, SRI LANKA, AZERBAIJAN, AUSTRALIA, AUSTRIA, PHILIPPINES, TURKEY, RUSSIA, IRAN, IRAQ, CANADA, KOREA, JAPAN, YEMEN, FINLAND, ZIMBABWE, HUNGARY, PORTUGAL, VIETNAM, MOROCCO, THAILAND, SOUTH AFRICA, MEXICO, SINGAPORE, GREECE, KUWAIT, POLAND, NEW ZEALAND, SWEDEN, SWITZERLAND, BELGIUM, BHUTAN, BANGLADESH, TAIWAN, ROMANIA, CAMBODIA, KAZAKHSTAN, AFGHANISTAN.
