Resistance-heating properties
Room-temperature resistivity Required by the standard
| Form and size band | ρ (20 °C) / μΩ·m |
|---|---|
| Wire, dia. <0.50 mm | 1.09 ± 0.05 |
| Wire, dia. 0.50–3.00 mm | 1.13 ± 0.05 |
| Wire, dia. >3.00 mm | 1.14 ± 0.05 |
| Strip, t ≤0.80 mm | 1.09 ± 0.05 |
| Strip, t >0.80–3.00 mm | 1.13 ± 0.05 |
| Strip, t >3.00 mm | 1.14 ± 0.05 |
Applies to soft (annealed / solution-treated) material only. The size bands differ between wire and strip — wire splits at 0.50 mm, strip at 0.80 mm — so the same 1.09 figure covers different sizes; look it up by the actual product form.
⚠ Where wire (or strip) is accepted on ohms-per-metre, the room-temperature resistivity is not an acceptance item; the ohms-per-metre requirement governs instead.
Resistance-temperature factor Informative only — not a basis for acceptance
| Temperature / °C | Factor k |
|---|---|
| 20 | 1.000 |
| 100 | 1.006 |
| 200 | 1.012 |
| 300 | 1.018 |
| 400 | 1.025 |
| 500 | 1.026 |
| 600 | 1.018 |
| 700 | 1.010 |
| 800 | 1.008 |
| 900 | 1.010 |
| 1000 | 1.014 |
| 1100 | 1.021 |
| 1200 | 1.025 |
Multiply the 20 °C resistivity by this factor to obtain the resistivity at temperature.
For 80/20 nickel-chromium the factor peaks near 500 °C (1.026), falls back to 1.008 at 800 °C and then rises slowly again — the whole curve stays between 1.000 and 1.026. An element on a fixed supply voltage therefore changes resistance by less than 3% between cold and working temperature: inrush current is small and power barely drifts with temperature. That is what makes nickel-chromium elements comparatively easy to design.
No temperature factor is given for Cr20Ni80 at 1300 °C, and none is extrapolated.
Rapid life test Required by the standard
| Test temperature | 1200 | °C |
| Rapid life, min. | 80 | h |
Tested to GB/T 13300, "Rapid life test for high-resistance heating alloys".
⚠ 1200 °C is the TEST temperature, not a service temperature. The rapid life test is an accelerated screen for the oxidation resistance of a heat; reading it as "this alloy may be used continuously at 1200 °C" is a misreading. Actual element temperature depends on surface loading, furnace atmosphere, support arrangement and the life you will accept — none of which the standard specifies.
No maximum service temperature is specified at all.
Ohms-per-metre uniformity Required by the standard
| Wire | Ohms-per-metre uniformity within any spool: ≤4% |
| Strip | Ohms-per-metre uniformity within any coil of cold-rolled strip: ≤5% |
Uniformity is calculated as RJY = 2(R1−R2)/(R1+R2) × 100%, where R1 and R2 are the highest and lowest ohms-per-metre on the same spool.
The supplier may waive or sample-check this where it can guarantee conformity, so per-spool measured data has to be written into the contract.
Recommended heat treatment Informative only — not a basis for acceptance
| Solution | 980-1150 °C, water or air cool |
This is a recommended heat treatment, not an acceptance requirement.
Applies to wire and strip over 2 mm in diameter or thickness.
Chemical composition
Nominal: mid-range where both limits are given, the cap where only a maximum is, balance takes the remainder. Exact specified ranges below.
| Element | Name | Content % | |
|---|---|---|---|
| Main elements3 elements | |||
| Ni | Nickel | Bal. | |
| Cr | Chromium | 20 – 23% | |
| Si | Silicon | 0.75 – 1.6% | |
| Element | Name | Content % | |
|---|---|---|---|
| Minor & residual6 elements | |||
| Al | Aluminium | ≤ 0.5% | |
| Fe | Iron | ≤ 1% | |
| C | Carbon | ≤ 0.08% | |
| Mn | Manganese | ≤ 0.6% | |
| P | Phosphorus | ≤ 0.02% | |
| S | Sulphur | ≤ 0.015% | |
Mechanical minima by form
Guaranteed values differ by form, size and delivery condition; quotations confirm the specification, form, size and condition.
| Form | Condition | Rm MPa | Rp0.2 MPa | A ≥ % | Other requirements and notes |
|---|---|---|---|---|---|
| Wire and filler metals | |||||
| Wire, dia. >3.00 mm / NiCr strip over 0.200 mm thick | Solution treated (soft) | ≥ 650 | — | ≥ 25 | |
| Wire, dia. 0.10–3.00 mm | Solution treated (soft) | ≥ 650 | — | ≥ 20 | |
| Wire | Rapid life test | — | — | — | Also specified: Rapid life ≥ 80 h @ 1200 °C |
| Several forms | |||||
| Wire and strip over 2 mm in diameter or thickness | Solution treatment recommended | — | — | — | Also specified: Heat treatment 980–1150 °C, water quench or air cool |
Where this grade is recommended
Matched in 1 service conditions; ranks and scores computed from the condition-scoring matrix.
| Service condition | Industry | Temperature | Rank | Score |
|---|---|---|---|---|
| Heating elements & electrodes | Furnaces & Vacuum | 1000 – 1400 °C | 7 / 7 | 86 |
Designations & equivalents
| UNS | N06023 |
| W.Nr. (Germany) | 2.4869 |
| EN designation | NiCr8020 |
| Trade name(s) | Nichrome 80/20 / Nikrothal 80 / Chromel A / Brightray B / Cronix 80 |
| ASTM / AISI | B344 |
| GOST (Russia) | ≈ Х20Н80 |
Cross-references are common near-equivalents for search and shortlisting; substitution across standards requires clause-by-clause verification. All grades in one cross-reference table →
Applicable standards
2 specifications. Name the standard and its edition on the order.
Guaranteed values and required tests differ between specifications — see Mechanical minima by form for the figures per form.
Frequently asked questions
What is Nichrome 80/20?
Nichrome 80/20 — Resistance heating alloys. The Ni-Cr heating workhorse — 1200 °C in air
What is the maximum service temperature of Cr20Ni80?
Typically about 1200 °C; the practical limit depends on media, stress and design life — acceptance per the governing standard.
What is the tensile strength of Cr20Ni80?
The specified minimum tensile strength is 650 MPa for the main product form. Minima for other forms and sizes are listed under "Mechanical minima by form" on this page.
Which standards cover Cr20Ni80?
GB/T 1234—2012, ASTM B344
Where is Cr20Ni80 typically used?
Heating elements & electrodes (Furnaces & Vacuum)
In which forms is Cr20Ni80 available?
Tube, plate, strip, bar, forgings, wire and other forms — sizes and delivery condition confirmed per order, with EN 10204 3.1 / 3.2 certification.
Same series
Download PDF datasheet
This grade’s datasheet as an A4 PDF — for filing, printing or forwarding to colleagues.
Download PDF datasheetSupply & enquiry
Tube & pipeφ1 – 219 × 0.25 – 25 mm
Plate4.76 – 80 mm
Barφ8 – 300 mm
Wire & filler metalsφ0.01 – 8 mmFor this grade we can supply, against your service conditions:
- Tube, plate, strip, bar, forgings, wire and more — with size range and lead time
- Chemistry and mechanical test report (EN 10204 3.1 / 3.2)
- Like-for-like alternatives and selection advice
- Applicable standards and inspection scope
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