Nickel Alloy NiCr80/20-SR (Stress relieved)
Heat-treated state
UNS N06003 · ASTM B344 · JIS NCHW1 · GB Cr20Ni80
Use when coiled or formed elements must keep dimensional stability on first heat-up without full softening.
Values for the SR condition
Other NiCr80/20 tempers and conditions
NiCr80/20 is listed in 6 conditions; see the grade overview at NiCr80/20.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Heavy sections for furnace fixtures, cast-in elements and machined resistor bars. | 350 | 690 | 38 | 155 HB | 1.6 % IACS |
AnnealedDefault soft (bright/strand annealed wire, strip, ribbon) | Default stocked condition: soft, fully ductile wire/ribbon for coiling heating elements. | 400 | 700 | 35 | 160 HB | — |
Quarter hard | Slight cold work for straighter wire and better handling stiffness while keeping useful ductility. | 620 | 830 | 20 | 19 HRC | 1.6 % IACS |
SRThis page Stress relieved | Use when coiled or formed elements must keep dimensional stability on first heat-up without full softening. | 620 | 860 | 18 | 21 HRC | 1.6 % IACS |
Half hard | Pick for stiffer ribbon/strip and formed parts needing springback control before a final anneal. | 760 | 950 | 12 | 24 HRC | 1.6 % IACS |
Hardened | Maximum strength and straightness for spring-like or tension-loaded resistance elements; anneal or first-fire before tight coiling. | 980 | 1,150 | 4 | 34 HRC | — |
What is NiCr80/20-SR?
NiCr80/20-SR is NiCr80/20 heat treated to SR — use when coiled or formed elements must keep dimensional stability on first heat-up without full softening. NiCr80/20-SR has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 81% of nickel alloy grades. Elongation at break is 18% and the elastic modulus is 219 GPa (31.8 Msi). NiCr80/20-SR has a density of 8.4 g/cm³ (0.303 lb/in³), heavier than 57% of nickel alloy grades. It melts at 1,380°C (2,516 °F). Annealed is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- High service temperature — 1,150°C (2,102 °F), better than 95% of nickel alloy grades
- Easy to machine — 30/100, better than 90% of nickel alloy grades
- High strength — 620 MPa (89.9 ksi), better than 81% of nickel alloy grades
Limitations
- Hard to polish — 60/100, worse than 84% of nickel alloy grades
- Limited ductility — 18%, worse than 77% of nickel alloy grades
NiCr80/20-SR properties
Typical room-temperature values for NiCr80/20-SR; 22 are specific to this condition. Other listed values are NiCr80/20 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
NiCr80/20-SR has a density of 8.4 g/cm³ (0.303 lb/in³), heavier than 57% of nickel alloy grades. It melts at 1,380°C (2,516 °F).
Mechanical14
NiCr80/20-SR has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 81% of nickel alloy grades. Elongation at break is 18% and the elastic modulus is 219 GPa (31.8 Msi).
Thermal6
NiCr80/20-SR is rated for continuous service to 1,150°C (2,102 °F). It conducts heat at 11.3 W/m·K (6.53 BTU/hr·ft·°F), better than 50% of nickel alloy grades. Thermal expansion is 13.4 µm/m·K (7.44 µin/in·°F).
Electrical3
NiCr80/20-SR conducts electricity at 1.6 % IACS, better than 70% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), worse than 71% of nickel alloy grades.
Sustainability4
Producing a kilogram of NiCr80/20-SR takes about 145 MJ of energy and emits 11.5 kg of CO₂ — less than 77% of nickel alloy grades. Typical recycled content is 30%.
Manufacturability8
NiCr80/20-SR's machinability is poor (30/100, better than 90% of nickel alloy grades); weldability good (68/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with NiCr80/20-SR
Is NiCr80/20 easy to machine?
Gummy and strongly work-hardening — use rigid setups, sharp positive-rake carbide, heavy positive feed, low speed (~15–25 m/min) and flood coolant; avoid dwelling.
Can NiCr80/20 be welded?
Readily GTAW/resistance/spot welded with matching NiCr80/20 or Ni-Cr-Fe filler; keep heat input low, use argon shielding and avoid sulfur-bearing contaminants on the surface.
Can NiCr80/20 be formed, bent or molded?
Annealed wire and ribbon draw, coil and bend easily; work-hardens fast so interstage anneals (~1000–1100 °C, rapid cool) are needed for heavy cold reductions.
What surface finishes work on NiCr80/20?
Normally supplied bright annealed or pre-oxidised; a controlled first firing in air builds the protective Cr₂O₃ layer — do not paint or plate the hot zone, and keep it free of oil, sulfur and chlorides.
NiCr80/20 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 |
|---|---|---|
| CrGB/T 1234 Cr20Ni80 allows up to 23 | 19 – 21 | 20 |
| Fe | ≤ 1 | 0.5 |
| Siimproves scale adhesion | 0.75 – 1.6 | 1.2 |
| Mn | ≤ 1 | 0.4 |
| C | ≤ 0.1 | 0.05 |
| Al | ≤ 0.5 | 0.2 |
| Ti | ≤ 0.5 | 0.2 |
| S | ≤ 0.02 | 0.01 |
| P | ≤ 0.02 | 0.01 |
| Ca+REmicro-additions for oxide adherence | ≤ 0.1 | 0.03 |
| Nibalance, incl. Co | ≥ 77 (balance) | — |
NiCr80/20-SR — frequently asked
What is NiCr80/20-SR used for?
NiCr80/20-SR is typically used for toaster and heater elements, industrial furnace heating elements and resistors. In short: highest-temperature nichrome grade; stable resistance to 1150 °C; standard heating-element wire.
What is the yield strength of NiCr80/20-SR?
NiCr80/20-SR has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 81% of nickel alloy grades. Strength varies by condition: see the 6 listed tempers.
Is NiCr80/20-SR easy to machine?
Not especially — machinability is rated poor (30/100, better than 90% of nickel alloy grades). Gummy and strongly work-hardening — use rigid setups, sharp positive-rake carbide, heavy positive feed, low speed (~15–25 m/min) and flood coolant; avoid dwelling.
Can NiCr80/20-SR be welded?
Yes — weldability is rated good (68/100). Readily GTAW/resistance/spot welded with matching NiCr80/20 or Ni-Cr-Fe filler; keep heat input low, use argon shielding and avoid sulfur-bearing contaminants on the surface.
What surface finishes work on NiCr80/20-SR?
Normally supplied bright annealed or pre-oxidised; a controlled first firing in air builds the protective Cr₂O₃ layer — do not paint or plate the hot zone, and keep it free of oil, sulfur and chlorides.
Can NiCr80/20-SR be formed, bent or molded?
Annealed wire and ribbon draw, coil and bend easily; work-hardens fast so interstage anneals (~1000–1100 °C, rapid cool) are needed for heavy cold reductions.
What is the maximum service temperature of NiCr80/20-SR?
NiCr80/20-SR is rated for continuous use to about 1,150°C (2,102 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between NiCr80/20 Annealed and NiCr80/20-H?
Annealed is the default condition — default stocked condition: soft, fully ductile wire/ribbon for coiling heating elements. H: maximum strength and straightness for spring-like or tension-loaded resistance elements; anneal or first-fire before tight coiling. Yield strength is 400 MPa in Annealed versus 980 MPa in H.
Sources
- ASTM B344 — Drawn or Rolled Nickel-Chromium and Nickel-Chromium-Iron Alloys for Electrical Heating Elements — ASTM International (2019)
- GB/T 1234 — (Cr20Ni80) (2012)
- Nikrothal 80 resistance heating alloy datasheet — Kanthal / Alleima (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.