Nichrome 20 (UNS S31008 / W.Nr. 1.4843) is an austenitic nickel-chromium alloy for use at temperature up to 1050℃. The alloy is characterized by high resistivity and good oxidation resistance. It has good ductility after use and excellent weldability.
Equivalent Grades
| Trademark | GB | GOST | ASTM | UNS | DIN | W.Nr. | NF | BS | JIS | SS |
Nikrothal 20
Resistohm 20 | Cr25Ni20 | Х25Н20 | 310S | S31008 | CrNi25 20 | 1.4843 | – | – | – | – |
Chemical Composition, %
| Alloy | C | Si | Mn | P | S | Cr | Ni | Al | Fe |
| Nichrome 20 | ≤0.08 | 1.0-3.0 | ≤1.00 | ≤0.020 | ≤0.015 | 24.0-26.0 | 19.0-22.0 | – | Bal |
Mechanical Properties (RT, Annealed)
| Tensile Strength, Rm/MPa | Elongation, A/% |
Dia. >3.00mm (Wire)
Thk. >0.20mm (Strip) | Dia. 0.10-3.00mm (Wire)
Thk. ≤0.20mm (Strip) |
| ≥600 | ≥25 | ≥20 |
Physical Properties
| Max Working Temp., ℃ | Melting Point, ℃ | Density, g/cm3 | Resistivity, μΩ·m 20℃ | Specific Heat, J/(g•K) | Thermal Conductivity, W/(m•K) 20℃ | Average Coefficient of Thermal Expansion,α×10-6/℃ 20-1000℃ | Micrographic Structure | Magnetic Properties |
| 1100 | 1390 | 7.90 | 1.04 | 0.50 | 13 | 19.0 | Austenitie | Non-Magnetic |
Life Test
| Test Temperature, ℃ | Continuous Service Time Hours, ℃ |
| 1100 | ≥80 |
Temperature Factor of Resistivity
| 20℃ | 100℃ | 200℃ | 300℃ | 400℃ | 500℃ | 600℃ | 700℃ | 800℃ | 900℃ | 1000℃ | 1100℃ | 1200℃ | 1300℃ |
| 1.00 | 1.04 | 1.10 | 1.14 | 1.17 | 1.21 | 1.23 | 1.26 | 1.28 | 1.30 | 1.32 | 1.34 | – | – |
Available Products and Specifications
| Rod, Bar, Wire and Forgings | GB/T 1234-2012, ASTM B344-01, DIN 17470-1984 |
| Plate, Sheet and Strip | GB/T 1234-2012, ASTM B344-01, DIN 17470-1984 |
| Pipe and Tube | – |
| Welding Product | – |
| Others | – |
Features
- High resistivity
- Moderate oxidation resistance
- Good ductility after use
- Excellent weldability
Applications
- Terminals attached to nickel chromium heating elements
- Element fasteners
- Refractory anchor bolts
