Refractory Metal N1
N1 is a Chinese domestic Zr-1%Nb alloy standardized for nuclear fuel cladding and pressure tube use, roughly equivalent to Russian E110, and is stocked as RXA, SRA, PRXA, CW, BQ-RXA and HR-ANN.
Reference datasheet — N1 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the RXA condition
N1 tempers and conditions
N1 is supplied in 6 conditions, soft to hard. RXA is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
RXADefault Recrystallization annealed | Standard condition for PWR fuel cladding tube: maximum ductility, lowest irradiation growth, stable creep behaviour. | 260 | 420 | 30 | 150 HB | 3.1 % IACS |
Hot rolled + annealed | General mill product form for grid straps, end plugs and machined components rather than thin-wall tube. | 270 | 430 | 28 | 152 HB | 3.1 % IACS |
beta quenched then recrystallization annealed | Beta-quench homogenizes Nb distribution before final anneal; used for pressure-tube and corrosion-optimized cladding lots. | 280 | 440 | 28 | 157 HB | 3.1 % IACS |
Partially recrystallized annealed | Intermediate strength/ductility balance used for guide tubes and some cladding designs. | 350 | 480 | 22 | 166 HB | 3.1 % IACS |
Cold worked + stress-relief annealed | Choose where higher strength and creep-collapse resistance of the tube are needed and some ductility can be traded away. | 430 | 540 | 15 | 185 HB | 3 % IACS |
Cold worked | Intermediate mill condition or hard strip/wire where maximum strength is wanted and ductility is not critical. | 540 | 620 | 9 | 17 HRC | 3 % IACS |
What is N1?
N1 is a Chinese domestic Zr-1%Nb alloy standardized for nuclear fuel cladding and pressure tube use, roughly equivalent to Russian E110, and is stocked as RXA, SRA, PRXA, CW, BQ-RXA and HR-ANN. It is chosen for low neutron absorption combined with good ductility and formability (75/100), giving 260 MPa yield, 420 MPa tensile and 30% elongation, typically as thin-wall cladding tube, pressure tube and bar. Service temperature is limited to about 400 °C, machinability is low (32/100), and all joining must be done under vacuum or high-purity argon. E110 and M5 are the direct alternatives. N1 has a density of 6.55 g/cm³ (0.237 lb/in³), lighter than 77% of refractory metal grades. It melts at 1,850°C (3,362 °F). N1 has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 68% of refractory metal grades. Elongation at break is 30% and the elastic modulus is 97 GPa (14.1 Msi).
What is N1 used for?
- fuel cladding tubes
- pressure tubes
- reactor structural parts
Advantages
- Ductile — tolerates forming and impact — 30%, better than 86% of refractory metal grades
- Readily welded — 75/100, better than 81% of refractory metal grades
- Forms and bends easily — 75/100, better than 81% of refractory metal grades
- Lightweight — 6.55 g/cm³ (0.237 lb/in³), better than 77% of refractory metal grades
Limitations
- Low stiffness — 97 GPa (14.1 Msi), worse than 91% of refractory metal grades
- Low electrical conductivity — 3.1 % IACS, worse than 78% of refractory metal grades
N1 properties
Typical room-temperature values for N1-RXA; bars are the position among refractory metal grades.
Physical3
N1 has a density of 6.55 g/cm³ (0.237 lb/in³), lighter than 77% of refractory metal grades. It melts at 1,850°C (3,362 °F).
Mechanical16
N1 has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 68% of refractory metal grades. Elongation at break is 30% and the elastic modulus is 97 GPa (14.1 Msi).
Thermal6
N1 is rated for continuous service to 400°C (752 °F). It conducts heat at 18 W/m·K (10.4 BTU/hr·ft·°F), worse than 70% of refractory metal grades. Thermal expansion is 5.9 µm/m·K (3.28 µin/in·°F).
Electrical3
N1 conducts electricity at 3.1 % IACS, worse than 78% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 86% of refractory metal grades.
Sustainability4
Producing a kilogram of N1 takes about 1,200 MJ of energy and emits 72 kg of CO₂ — less than 51% of refractory metal grades. Typical recycled content is 10%.
Manufacturability8
N1's machinability is poor (32/100, better than 67% of refractory metal grades); weldability very good (75/100); formability very good (75/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the refractory metal family
Yield strength against density for every refractory metal grade FabDigit runs. N1 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with N1
Is N1 easy to machine?
Machine like titanium — sharp, positive-rake carbide, low speed / heavy feed, flood coolant; collect fines wet since dry chips and dust are pyrophoric.
Can N1 be welded?
GTAW or electron-beam in a high-purity argon chamber or vacuum with full back-purge; any O/N/H pickup embrittles the joint and degrades corrosion.
Can N1 be formed, bent or molded?
Cold pilgering plus intermediate vacuum anneals is the standard tube route; bend radii ≥3t cold, texture control governs irradiation growth.
N1 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Nbprincipal alloying element | 0.9 – 1.1 | 1 |
| Ocontrolled for strength | 0.05 – 0.12 | 0.09 |
| Fe | ≤ 0.05 | 0.03 |
| C | ≤ 0.02 | 0.01 |
| N | ≤ 0.01 | 0 |
| Hfnuclear grade — low neutron absorption | ≤ 0.01 | 0.01 |
| Si | ≤ 0.01 | |
| Ni | ≤ 0.01 | |
| Cr | ≤ 0.02 | |
| H | ≤ 0 | |
| Zr | balance |
What surface finishes work on N1?
Pickle in HNO3/HF then rinse thoroughly, or electropolish/autoclave-passivate to form the protective black oxide; avoid iron contamination from steel tooling.
Equivalent designations
Standards and trade names that resolve to Refractory Metal N1 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Zr-1Nb
How much does N1 cost?
N1 is a high-cost refractory metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
N1 — frequently asked
What is N1 used for?
N1 is typically used for fuel cladding tubes, pressure tubes and reactor structural parts. In short: domestic E110 equivalent; most formable Zr-1%Nb grade; low neutron absorption.
What is the yield strength of N1?
N1 has a typical yield strength of 260 MPa (37.7 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 68% of refractory metal grades. Strength varies by condition: see the 6 listed tempers.
Is N1 easy to machine?
Not especially — machinability is rated poor (32/100, better than 67% of refractory metal grades). Machine like titanium — sharp, positive-rake carbide, low speed / heavy feed, flood coolant; collect fines wet since dry chips and dust are pyrophoric.
Can N1 be welded?
Yes — weldability is rated very good (75/100). GTAW or electron-beam in a high-purity argon chamber or vacuum with full back-purge; any O/N/H pickup embrittles the joint and degrades corrosion.
What surface finishes work on N1?
Pickle in HNO3/HF then rinse thoroughly, or electropolish/autoclave-passivate to form the protective black oxide; avoid iron contamination from steel tooling.
Can N1 be formed, bent or molded?
Cold pilgering plus intermediate vacuum anneals is the standard tube route; bend radii ≥3t cold, texture control governs irradiation growth.
What is the maximum service temperature of N1?
N1 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between N1-RXA and N1-CW?
RXA is the default condition — standard condition for PWR fuel cladding tube: maximum ductility, lowest irradiation growth, stable creep behaviour. CW: intermediate mill condition or hard strip/wire where maximum strength is wanted and ductility is not critical. Yield strength is 260 MPa in RXA versus 540 MPa in CW.
How much does N1 cost?
N1 is a high-cost refractory metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B811 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding — ASTM International (2019)
- ASTM B350/B350M Zirconium and Zirconium Alloy Ingots for Nuclear Application — ASTM International (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Zirconium and Hafnium) — ASM International (1990)
- IAEA TECDOC series on zirconium alloy fuel cladding behaviour and thermophysical properties — IAEA (2010)
- Zr-1Nb (E110/M5-type) cladding tube technical data — nuclear zirconium tube producers (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.