FeCrAl -made Grade 216Nb(0Cr21Al6Nb)) resistance alloy is characterized by high resistivity, low resistance coefficient, high operating temperature, good oxidation resistance under high temperature, and a maximum applicable temperature of 1250℃.
What is the difference in performance between 0Cr21Al6Nb and 0Cr21Al6? It is all about the addition of the Niobium element.
| Grade | Chemical Composition(%) | |||||||||
| C | P | S | Mn | Si | Cr | Ni | Al | Nb | Fe | |
| Less than | ||||||||||
| 216Nb | 0.05 | 0.025 | 0.02 | 0.5 | 0.6 | 21~23 | ≦0.6 | 5.0~7.0 | 0.5 | Bal |
Note: DLX Alloy produces Grade 216Nb in the standard of GB/T1234-2012.
The Role of Niobium/Columbium (Nb/Cb) in FeCrAl Alloys
Niobium and columbium often coexist with tantalum, and their roles in alloys are similar. Niobium and tantalum partially dissolve into the solid solution, contributing to solid solution strengthening.
When dissolved in austenite, they significantly improve the alloy's hardenability. However, when present as carbide and oxide particles, they refine the grain size and reduce the alloy's hardenability.
They can increase the alloy's tempering stability and have a secondary hardening effect. Trace amounts of niobium can enhance the alloy's strength without affecting its plasticity or toughness.
Due to the grain refinement effect, niobium can improve the alloy's impact toughness and lower its brittle transition temperature.
When the niobium content is more than eight times the carbon content, it can almost completely fix all the carbon in the alloy, providing excellent hydrogen resistance.
In austenitic alloys, niobium can prevent intergranular corrosion caused by oxidizing media. Due to its ability to fix carbon and its precipitation-hardening effect, niobium can enhance the high-temperature properties of heat-resistant alloys, such as creep strength.
In summary, the Nb element in FeCrAl alloy can improve its impact toughness, lower brittle transaction temperature, and enhance creep strength.
Key Properties of Grade 216Nb
| Density (g/cm3) | 7.1 |
| Max. operating temperature (℃) | 1350 |
| Magnetic Properties | Magnetic |
| Resistivity (20℃)(Ω·mm2/m) | 1.45 |
| Tensile strength (Mpa) | 725 |
| Yield strength (Mpa) | 550 |
| Elongation (%) | 22 |
| Melting point (℃) | 1510 |
Specifications of 0Cr21Al6Nb Resistance Wire in DLX ALLOY
| Dimensions | Round wire Diameter 0.05mm to 6.0mm |
| Ribbon size Thick(0.05~0.5mm)* Width(0.5~6.0mm) | |
| Foils Thick(0.05~2.5mm)* Width(6~200mm) | |
| Round/Square/Hex Rods | |
| Surface Treatment | Black Oxidized/Sour White/Bright |
| Hardness | Hard/Soft |
| Package for Round Wire | Spooled(Dia 0.05mm to 1.2mm) Coil(over 1.2mm) |
Ferrous Chromium Aluminum alloy performance tables
| Alloy Nomenclature Performance | 1Cr13Al4 | 0Cr25Al5 | 0Cr21Al6 | 0Cr23Al5 | 0Cr21Al4 | 0Cr21Al6Nb | 0Cr27Al7Mo2 | |
| Main Chemical composition | Cr | 12.0-15.0 | 23.0-26.0 | 19.0-22.0 | 20.5-23.5 | 18.0-21.0 | 21.0-23.0 | 26.5-27.8 |
| Al | 4.0-6.0 | 4.5-6.5 | 5.0-7.0 | 4.2-5.3 | 3.0-4.2 | 5.0-7.0 | 6.0-7.0 | |
| Re | opportune | opportune | opportune | opportune | opportune | opportune | opportune | |
| Fe | Rest | Rest | Rest | Rest | Rest | Rest | Rest | |
| Nb0.5 | Mo1.8-2.2 | |||||||
| Max. continuous service temp. of element(°C) | 950 | 1250 | 1250 | 1250 | 1100 | 1350 | 1400 | |
| Resistivity at 20ºC(μΩ·m) | 1.25 | 1.42 | 1.42 | 1.35 | 1.23 | 1.45 | 1.53 | |
| Density(g/cm3) | 7.4 | 7.1 | 7.16 | 7.25 | 7.35 | 7.1 | 7.1 | |
| Thermal conductivity(KJ/m·h·ºC) | 52.7 | 46.1 | 63.2 | 60.2 | 46.9 | 46.1 | ||
| Coefficient of lines expansion(α×10-6/ºC) | 15.4 | 16 | 14.7 | 15 | 13.5 | 16 | 16 | |
| Melting point approx.( ºC) | 1450 | 1500 | 1500 | 1500 | 1500 | 1510 | 1520 | |
| Tensile strength(N/mm2) | 580-680 | 630-780 | 630-780 | 630-780 | 600-700 | 650-800 | 680-830 | |
| Elongation at rupture(%) | >16 | >12 | >12 | >12 | >12 | >12 | >10 | |
| Variation of area(%) | 65-75 | 60-75 | 65-75 | 65-75 | 65-75 | 65-75 | 65-75 | |
| Repeat Bending frequency(F/R) | >5 | >5 | >5 | >5 | >5 | >5 | >5 | |
| Hardness(H.B.) | 200-260 | 200-260 | 200-260 | 200-260 | 200-260 | 200-260 | 200-260 | |
| Continuous Servicetime(Hours/ ºC) | -- | ≥80/1300 | ≥80/1300 | ≥80/1300 | ≥80/1250 | ≥50/1350 | ≥50/1350 | |
| Micrographic structure | Ferrite | Ferrite | Ferrite | Ferrite | Ferrite | Ferrite | Ferrite | |
| Magnetic properties | Magnetic | Magnetic | Magnetic | Magnetic | Magnetic | Magnetic |
Magnetic | |
