R04200 Pure Niobium Fittings – ASTM B392 / B394, Reactor Grade
What are R04200 niobium fittings?
They are pipe fittings – elbows, tees, reducers, caps, stub ends and couplings – made from pure (unalloyed) niobium, reactor grade UNS R04200 (ASTM Type 1). R04200 is the highest-purity commercial niobium grade, with very low oxygen, tantalum and metallic impurities. It is soft, ductile and easy to weld, and resists most acids at moderate temperatures – often as a lower-cost alternative to tantalum.
Specifications: ASTM B392 covers niobium bar, rod and wire; ASTM B394 covers seamless and welded tube. R04200 fittings are machined from B392 bar or formed from B394 tube, and certified to those standards.
R04200 Niobium Fittings – Quick Facts
- Grade: unalloyed niobium, reactor grade, UNS R04200 (Type 1)
- Raw material: ASTM B392 bar / rod, ASTM B394 tube, ASTM B393 plate
- Fitting types: butt-weld elbows, tees, reducers, caps, stub ends; socket-weld and threaded fittings machined from bar
- Dimensions: ASME B16.9 / B16.11 profiles or customer drawing
- Condition: annealed (at least 90% recrystallized), pickled and clean
- Certificate: EN 10204 3.1 with interstitial (C, O, N, H) analysis
ASC LLP, Mumbai, supplies R04200 niobium fittings with matching flanges, fasteners and tube. See all niobium fittings or our niobium & niobium alloy range.
R04200 Chemical Composition (ASTM B392)
| Element (max %) | R04200 – Type 1 (reactor grade) | R04210 – Type 2 (commercial grade) |
| Oxygen (O) | 0.015 | 0.025 |
| Carbon (C) | 0.01 | 0.01 |
| Nitrogen (N) | 0.01 | 0.01 |
| Hydrogen (H) | 0.0015 | 0.0015 |
| Tantalum (Ta) | 0.1 | 0.3 |
| Tungsten (W) | 0.03 | 0.05 |
| Molybdenum (Mo) | 0.010 | 0.020 |
| Zirconium (Zr) | 0.02 | 0.02 |
| Titanium (Ti) | 0.02 | 0.03 |
| Hafnium (Hf) | 0.02 | 0.02 |
| Iron (Fe) | 0.005 | 0.01 |
| Silicon (Si) | 0.005 | 0.005 |
| Nickel (Ni) | 0.005 | 0.005 |
| Niobium (Nb) | Remainder | Remainder |
Limits per ASTM B392 (ingot analysis). R04200 has tighter limits than commercial-grade R04210 – especially oxygen and tantalum – and is chosen for nuclear, superconducting and high-purity service.
Mechanical Properties – R04200 vs Nb-1Zr vs C-103
| Grade (annealed) | Tensile strength (min) | 0.2% yield strength (min) | Elongation (min) |
| R04200 / R04210 – pure niobium | 125 MPa (18 ksi) | 73 MPa (10.5 ksi) | 25% |
| Nb-1Zr (R04251 / R04261) | 195 MPa (28 ksi) | 125 MPa (18 ksi) | 20% |
| C-103 (R04295) | 370 MPa (54 ksi) | 260 MPa (38 ksi) | 20% |
Minimum values for annealed material per ASTM B392 / B394 (C-103 per B655). Pure niobium is soft and very ductile – it is chosen for corrosion resistance and purity, not strength. Where more strength is needed, use Nb-1Zr or C-103.
Types of R04200 Niobium Fittings
| Fitting type | Typical production route | Dimensional profile |
| Butt-weld elbows (45°, 90°, 180°) | Formed from ASTM B394 seamless or welded tube | ASME B16.9 or drawing |
| Equal & reducing tees | Formed from tube or machined from bar | ASME B16.9 or drawing |
| Concentric & eccentric reducers | Formed from tube | ASME B16.9 or drawing |
| Caps & stub ends | Formed from plate (B393) or machined from bar (B392) | ASME B16.9 or drawing |
| Socket-weld & threaded fittings | Machined from ASTM B392 bar | ASME B16.11 or drawing |
Niobium fittings are usually small-bore – typically ½” to 4″ NB – and are often made to drawing. ASME B16 standards are used for dimensions only; pressure ratings for niobium are set by the purchaser’s design calculation.
Corrosion Resistance of Pure Niobium
- Resists: nitric acid, hydrochloric acid (at moderate concentration and temperature), dilute sulphuric and phosphoric acids, most organic acids, chloride solutions, wet chlorine and bromine, and many liquid metals.
- Attacked by: hydrofluoric acid and fluorides, hot concentrated sulphuric and phosphoric acids, fuming sulphuric acid (oleum) and strong alkalis.
- Hydrogen: niobium can absorb hydrogen and become brittle if it is coupled to a less noble metal in acid, or exposed to hydrogen at high temperature.
- Oxidation: niobium oxidises in air above about 400 °C – high-temperature service must be in vacuum or inert gas.
For the most severe hot acids, tantalum performs better; for moderate conditions, niobium gives similar protection at lower cost and about half the weight.
R04200 Niobium Fittings Specifications
| Item | Details |
| Product | R04200 pure niobium pipe fittings |
| Grade | UNS R04200 (Type 1, reactor grade); R04210 on request |
| Material standards | ASTM B392 (bar), ASTM B394 (tube), ASTM B393 (plate / sheet) |
| Fitting types | Elbows, tees, reducers, caps, stub ends, couplings, unions, plugs, bushings |
| Dimensions | ASME B16.9, ASME B16.11 profiles, or customer drawing |
| Sizes | Typically ½” – 4″ NB; other sizes to drawing |
| Ends | Butt-weld (square or bevelled), socket-weld, threaded |
| Condition | Annealed, pickled and clean |
| Testing | Chemical incl. interstitials, tensile, dimensional, visual; dye penetrant on request |
| Certificate | EN 10204 3.1; third-party inspection on request |
Welding & Fabrication
- Welding: TIG or electron-beam welding in a high-purity argon chamber or vacuum; oxygen or nitrogen pick-up makes the weld brittle.
- Forming: R04200 can be bent, flared and deep-drawn at room temperature.
- Machining: soft and gummy – use sharp tools, positive rake and plenty of coolant to avoid galling.
- Annealing: only in vacuum or inert gas, never in air.
Physical Properties of Pure Niobium
| Property | Value (approx.) |
| Density | 8.57 g/cm³ |
| Melting point | ≈ 2,477 °C (4,491 °F) |
| Thermal conductivity | ≈ 54 W/m·K |
| Coefficient of thermal expansion | ≈ 7.3 µm/m·°C |
| Superconducting transition | ≈ 9.2 K |
| Magnetic | Non-magnetic |
Applications of R04200 Niobium Fittings
| Industry | Applications of R04200 niobium fittings |
| Chemical processing | Acid piping, heat-exchanger connections, condensers and thermowells (nitric and hydrochloric acid service) |
| Superconducting & research | Cryogenic and vacuum piping for RF cavity and accelerator systems |
| Nuclear | High-purity piping and test hardware |
| Vacuum & furnace | Vacuum and inert-gas furnace connections |
| Electronics & coating | Piping for PVD / sputtering and high-purity process equipment |
Pure niobium is not used for rocket nozzles or other hot load-bearing parts – those use the C-103 niobium alloy.
Why Buy R04200 Niobium Fittings from ASC LLP?
- Correct grade and paperwork: R04200 to ASTM B392 / B394, with 3.1 certificates showing oxygen, tantalum and other interstitials.
- Complete R04200 line: R04200 flanges, R04200 fasteners, R04200 pipes and R04200 plates.
- Fittings from tube: see R04200 fittings to ASTM B394.
- Small quantities and drawings welcome – prototypes, test loops and spares.
Send grade, fitting type, size, wall and quantity to sales@amardeepsteel.com or call 022-67439130.
Frequently Asked Questions – R04200 Niobium Fittings
What is R04200 niobium?
UNS R04200 is reactor-grade unalloyed (pure) niobium, ASTM Type 1. It has the tightest impurity limits of the commercial niobium grades – for example oxygen 0.015% and tantalum 0.1% maximum.
What is the difference between R04200 and R04210 niobium?
Both are pure niobium with the same minimum strength. R04200 (reactor grade) has tighter limits on oxygen, tantalum, tungsten and molybdenum; R04210 (commercial grade) allows slightly more impurities and costs less.
What is the strength of R04200 niobium fittings?
Annealed R04200 niobium has a minimum tensile strength of 125 MPa (18 ksi), minimum yield strength of 73 MPa (10.5 ksi) and minimum elongation of 25% per ASTM B392 and B394.
Which ASTM standard covers R04200 niobium fittings?
There is no separate niobium fittings standard. Fittings are machined from ASTM B392 bar or formed from ASTM B394 tube (and B393 plate), and are certified to those material standards.
Is pure niobium resistant to acids?
Yes, pure niobium resists nitric acid, moderate hydrochloric acid, dilute sulphuric acid and most organic acids. It is attacked by hydrofluoric acid, hot concentrated sulphuric acid and strong alkalis.
When should I use Nb-1Zr or C-103 instead of pure niobium?
Use Nb-1Zr when you need more strength or high-temperature performance in vacuum, inert gas or liquid metal, and C-103 for load-bearing parts at very high temperature. Pure niobium is best where corrosion resistance and purity matter more than strength.
Global Reach
ASC LLP supplies niobium, tantalum and other refractory-metal products to chemical, research, nuclear and electronics customers worldwide, with secure packing and full documentation. Buyers in the USA, Europe, the Middle East and Asia rely on our R04200 pure 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.
