Cr20Ni35 Heat Resistant Nickel Chromium Iron Alloy with High Positive Temperature Coefficient
Cr20Ni35 Heat-Resistant Nickel-Chromium-Iron Alloy with High Positive Temperature Coefficient
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Chemical Composition Wt.% Cr20Ni35 |
% | Ni | Fe | C | Si | Mn | P | S | Cr |
| Min | 34 | 1 | 18 | ||||||
| Max | 37 | Rest | 0.08 | 3 | 1 | 0.02 | 0.015 | 21 |
Main characteristics of Ni-Cr and Ni-Cr-Fe electric heating alloys
|
Type
|
Cr30Ni70 | Cr15Ni60 | Cr20Ni35 | Cr20Ni80 | Cr20Ni30 | Cr25Ni20 | |
| Main Chemical composition | Ni | Rest | 55.0-61.0 | 34.0-37.0 | Rest | 30.0-34.0 | 19.0-22.0 |
| Cr | 28.0-31.0 | 15.0-18.0 | 18.0-21.0 | 20.0-23.0 | 18.0-21.0 | 24.0-26.0 | |
| Fe | ≤ 1.0 | Rest | Rest | ≤ 1.0 | Rest | Rest | |
| Max. continuous service temp. of element (℃) | 1250 | 1150 | 1100 | 1200 | 1100 | 1050 | |
| Resistivity at 20 ℃(μΩm) | 1.18±0.05 | 1.12±0.05 | 1.04±0.05 | 1.09±0.05 | 1.06±0.05 | 0.95±0.05 | |
| Density(g/cm3) | 8.10 | 8.20 | 7.90 | 8.40 | 7.90 | 7.15 | |
| Thermal condyctivity (KJ/m·h·℃) | 45.2 | 45.2 | 43.8 | 60.3 | 43.8 | 43.8 | |
| Coefficient of lines expansion (α×10-6/℃) | 17.0 | 17.0 | 19.0 | 18.0 | 19.0 | 19.0 | |
| Melting point (approx.)(℃) | 1380 | 1390 | 1390 | 1400 | 1390 | 1400 | |
| Elonation at rupture(%) | ＞20 | ＞20 | ＞20 | ＞20 | ＞20 | ＞20 | |
| Micrographic structure | Austenite | Austenite | Austenite | Austenite | Austenite | Austenite | |
| Magnetic properties | Non-magnetic | Low-magnetic | Low-magnetic | Non-magnetic | Low-magnetic | Non-magnetic | |
| Note:The various grades of electric resistance alloy material are blended with the amountof rare earth, titanium and other trace elements, to improve the processing performance andextend the period of the uselife. | |||||||
Key Features of NiCr Alloy Wire Cr20Ni35:
- Composition:
Nickel (Ni): 35% (provides excellent high-temperature stability and good electrical resistivity).
Chromium (Cr): 20% (enhances oxidation resistance and improves strength at high temperatures).
Iron (Fe): The balance, used to enhance the overall mechanical properties of the alloy.
Carbon (C): Low content to improve machinability and prevent carbide precipitation during heat exposure.
- High-Temperature Resistance:
Designed to withstand continuous exposure to temperatures up to 1100°C (2012°F).
Maintains strength and stability at elevated temperatures, making it suitable for resistive heating applications and other high-heat environments.
- Oxidation and Corrosion Resistance:
Oxidation Resistance: The alloy has a high degree of oxidation resistance due to the chromium content, which forms a stable oxide layer that prevents further oxidation.
Corrosion Resistance: With its significant chromium content, it also offers resistance to corrosion in many environments, particularly oxidizing atmospheres at high temperatures.
- Electrical Resistivity:
Stable Electrical Resistivity: Offers a predictable and stable resistance under high temperatures, making it ideal for heating elements, resistors, and thermocouples.
Good Heat Generation Efficiency: Due to its resistive properties, it generates heat efficiently when used in electrical heating applications.
- Mechanical Properties:
Strength and Ductility: Provides good tensile strength at high temperatures and remains ductile enough for fabrication.
Thermal Fatigue Resistance: Resistant to thermal cycling, making it ideal for applications that undergo repeated heating and cooling cycles.
- Weldability and Fabrication:
Weldable: Can be welded using standard welding techniques such as TIG (GTAW) and MIG (GMAW) welding, with minimal risk of cracking or other issues.
Formability: Easily drawn into wires, rods, and other shapes for a variety of applications, particularly in heating elements and electrical components.
Applications:
- Heating Elements: Commonly used in industrial furnaces, electric heating elements, and ovens where high-temperature stability is critical.
- Resistors: Used in the manufacturing of precision resistors and resistor grids that require stable electrical resistance.
- Thermocouples and Sensors: Suitable for high-temperature thermocouples and temperature sensing elements.
- Electrical Components: Often found in electrical heating components such as toasters, dryers, water heaters, and other similar products.
- High-Temperature Applications: Also used in some chemical processing applications that require materials resistant to high heat and oxidation.
Technical data of wires
| Dia. (mm) | Cross-sectional area (mm²) | Weight/Meter (g/m) | Resistance/Meter at 20 ℃ (Ω/m) | Dia. (mm) | Cross-sectional area (mm²) | Weight/Meter (g/m) | Resistance/Meter at 20 ℃ (Ω/m) |
| 0.018 | 0.000255 | 0.002117 | 3410-4610 | 0.25 | 0.04909 | 0.4074 | 20.88-23.54 |
| 0.020 | 0.000314 | 0.002606 | 2940-3740 | 0.28 | 0.06158 | 0.5111 | 16.64-18.76 |
| 0.022 | 0.000380 | 0.003154 | 2440-3100 | 0.30 | 0.07069 | 0.5867 | 14.49-16.35 |
| 0.025 | 0.000491 | 0.004075 | 1880-2400 | 0.32 | 0.07548 | 0.6265 | 12.74-14.36 |
| 0.028 | 0.000616 | 0.005113 | 1530-1870 | 0.33 | 0.08553 | 0.7099 | 12.20-13.40 |
| 0.030 | 0.000707 | 0.005868 | 1338-1696 | 0.38 | 0.1134 | 0.9412 | 9.13-10.09 |
| 0.032 | 0.000804 | 0.006673 | 1180-1440 | 0.40 | 0.1257 | 1.0433 | 8.24-9.108 |
| 0.035 | 0.000962 | 0.007985 | 981-1200 | 0.41 | 0.132 | 1.0956 | 7.68-8.89 |
| 0.040 | 0.001257 | 0.01043 | 780.7-954.1 | 0.45 | 0.159 | 1.3197 | 6.51-7.196 |
| 0.045 | 0.00159 | 0.0132 | 594-726 | 0.50 | 0.1963 | 1.6293 | 5.273-5.829 |
| 0.050 | 0.001963 | 0.01629 | 499.6-610.6 | 0.55 | 0.2376 | 1.9721 | 4.518-4.994 |
| 0.055 | 0.00238 | 0.01975 | 407-477 | 0.60 | 0.2827 | 2.3464 | 3.797-4.197 |
| 0.063 | 0.00312 | 0.02590 | 321.41-377.31 | 0.65 | 0.3318 | 2.7539 | 3.235-3.575 |
| 0.070 | 0.00385 | 0.03196 | 260.5-305.9 | 0.70 | 0.3848 | 3.1938 | 2.789-3.083 |
| 0.080 | 0.005027 | 0.04172 | 199.5-234.1 | 0.75 | 0.4418 | 3.6669 | 2.43-2.686 |
| 0.090 | 0.006362 | 0.0528 | 157.6-185.0 | 0.80 | 0.5027 | 4.1724 | 2.136-2.36 |
| 0.100 | 0.007854 | 0.0652 | 127.7-149.9 | 0.85 | 0.5674 | 4.7094 | 1.891-2.091 |
| 0.110 | 0.009852 | 0.08177 | 105.5-123.9 | 0.90 | 0.6362 | 5.2805 | 1.687-1.865 |
| 0.120 | 0.01227 | 0.1018 | 88.67-104.1 | 0.95 | 0.7088 | 5.883 | 1.46-1.62 |
| 0.140 | 0.01539 | 0.1277 | 65.85-75.77 | 1.00 | 0.7854 | 6.5188 | 1.367-1.511 |
| 0.150 | 0.01767 | 0.1467 | 56.75-66.63 | 1.10 | 0.9503 | 7.8875 | 1.13-1.26 |
| 0.160 | 0.02011 | 0.01669 | 50.42-58.00 | 1.12 | 0.9852 | 8.1772 | 1.05-1.17 |
| 0.170 | 0.022700 | 0.1884 | 44.18-51.86 | 1.18 | 1.0936 | 9.0769 | 0.95-1.05 |
| 0.180 | 0.02545 | 0.2112 | 40.26-45.40 | 1.20 | 1.313 | 10.8979 | 0.79-0.87 |
| 0.190 | 0.02835 | 0.2353 | 35.37-41.53 | 1.30 | 1.327 | 11.0141 | 0.78-0.86 |
| 0.200 | 0.03142 | 0.2608 | 32.62-36.78 | 1.40 | 1.539 | 12.7737 | 0.70-0.77 |
| 0.212 | 0.035300 | 0.2930 | 28.41-33.35 | 1.50 | 1.767 | 14.6661 | 0.60-0.67 |
| 0.220 | 0.03801 | 0.3155 | 26.65-30.39 | 1.60 | 2.011 | 16.8924 | 0.52-0.58 |
The tolerance or wires diameter
| Wires | Dia.(mm) | Tolerance |
| 0.018-0.025 | ±0.001 | |
| 0.028-0.035 | ±0.0015 | |
| 0.040-0.055 | ±0.002 | |
| 0.070 | ±0.0025 | |
| 0.08-0.10 | ±0.003 | |
| 0.11-0.14 | ±0.004 | |
| 0.16-0.20 | ±0.005 | |
| 0.22-0.25 | ±0.006 | |
| 0.28-0.30 | ±0.007 | |
| 0.32-0.40 | ±0.01 | |
| 0.41-0.50 | ±0.015 | |
| 0.55-0.80 | +0.02/-0.03 | |
| 0.85-1.00 | +0.02/-0.03 | |
| 1.10-1.50 | ±0.03 | |
| Note:special specification can be produced as per client's request. | ||
Technical data of ribbon
| Thickness × Width(mm) | Resistance/meter(20 ℃) (Ω/m) | Surface area/ohm (20℃) (cm2/Ω) | Weight/meter (g/m) | Surface area/meter (cm2/m) |
| 0.09x2.5 | 5.27 | 9.84 | 1.72 | 51.8 |
| 0.08x0.2 | 74 | 0.0756 | 0.122 | 5.6 |
| 0.08x0.3 | 49.4 | 0.154 | 0.183 | 7.6 |
| 0.08x0.4 | 37 | 0.259 | 0.244 | 9.6 |
| 0.08x0.5 | 29.6 | 0.392 | 0.305 | 11.6 |
| 0.08x0.6 | 24.7 | 0.551 | 0.367 | 13.6 |
| 0.08x0.7 | 21.2 | 0.737 | 0.428 | 15.6 |
| 0.08x0.8 | 18.5 | 0.951 | 0.489 | 17.6 |
| 0.08x0.9 | 16.5 | 1.19 | 0.55 | 19.6 |
| 0.08x1.0 | 14.8 | 1.46 | 0.611 | 21.6 |
| 0.08x1.2 | 12.3 | 2.07 | 0.733 | 25.6 |
| 0.08x1.5 | 9.87 | 3.2 | 0.916 | 31.6 |
| 0.08x1.8 | 8.23 | 4.57 | 1.1 | 37.6 |
| 0.08x2.0 | 7.4 | 5.62 | 1.22 | 41.6 |
| 0.07x0.2 | 84.6 | 0.0638 | 0.107 | 5.4 |
| 0.07x0.3 | 56.4 | 0.131 | 0.16 | 7.4 |
| 0.07x0.4 | 42.3 | 0.222 | 0.214 | 9.4 |
| 0.07x0.5 | 33.9 | 0.337 | 0.267 | 11.4 |
| 0.07x0.6 | 28.2 | 0.475 | 0.321 | 13.4 |
| 0.07x0.7 | 24.2 | 0.637 | 0.374 | 15.4 |
| 0.07x0.8 | 21.2 | 0.822 | 0.428 | 17.4 |
| 0.07x0.9 | 18.8 | 1.03 | 0.481 | 19.4 |
| 0.07x1.0 | 16.9 | 1.26 | 0.535 | 21.4 |
| 0.07x1.2 | 14.1 | 1.8 | 0.641 | 25.4 |
| 0.07x1.5 | 11.3 | 2.78 | 0.802 | 31.4 |
| 0.06x0.2 | 98.7 | 0.0527 | 0.0916 | 5.2 |
| 0.06x0.3 | 65.8 | 0.109 | 0.137 | 7.2 |
| 0.06x0.4 | 49.4 | 0.186 | 0.183 | 9.2 |
| 0.06x0.5 | 39.5 | 0.284 | 0.229 | 11.2 |
| 0.06x0.6 | 32.9 | 0.401 | 0.275 | 13.2 |
| 0.06x0.7 | 28.2 | 0.539 | 0.321 | 15.2 |
| 0.06x0.8 | 24.7 | 0.697 | 0.367 | 17.5 |
| 0.06x0.9 | 21.9 | 0.875 | 0.412 | 19.2 |
| 0.06x1.0 | 19.7 | 1.07 | 0.458 | 21.2 |
| 0.06x1.2 | 16.5 | 1.53 | 0.55 | 25.2 |
| 0.05x0.2 | 118 | 0.0422 | 0.0764 | 5.00 |
| 0.05x0.3 | 79 | 0.0886 | 0.115 | 7.00 |
| 0.05x0.4 | 59.2 | 0.152 | 0.153 | 9.00 |
| 0.05x0.5 | 47.4 | 0.232 | 0.191 | 11.00 |
| 0.05x0.6 | 39.5 | 0.329 | 0.229 | 13.00 |
| 0.05x0.7 | 33.9 | 0.443 | 0.267 | 15.0 |
| 0.05x0.8 | 29.6 | 0.574 | 0.305 | 17.0 |
| 0.05x0.9 | 16.3 | 0.722 | 0.344 | 19.0 |
| 0.05x1.0 | 23.7 | 0.886 | 0.382 | 21.0 |
| Ribbon is rolled by the wire, the actual cross-sectional area of the ribbon is smaller 8％ than calculated by the rectangular. | ||||
Advantages of NiCr Alloy Wire Cr30Ni35:
- High-Temperature Performance: Excellent resistance to high-temperature oxidation, making it suitable for environments up to 1100°C (2012°F).
- Good Electrical Resistivity: Ideal for use in heating elements, resistors, and other electrical applications where stable resistivity is required.
- Corrosion Resistance: Resists corrosion in a range of high-temperature, oxidizing conditions.
- Fatigue and Thermal Cycling Resistance: Withstands repeated heating and cooling without degradation.
- Fabrication Flexibility: Can be easily fabricated into wire forms for a range of applications, especially in industrial and electrical environments.
Limitations of NiCr Alloy Wire Cr30Ni35:
- Cost: As with most high-performance alloys, it may be more expensive compared to other metals like stainless steel, which may limit its application in cost-sensitive areas.
- Limited Resistance to Strong Acids: While it is highly resistant to oxidation, it may not perform as well in strongly acidic or highly corrosive environments compared to specialized alloys like Inconel or Hastelloy.
- Cold Work Hardening: Can work-harden during cold-forming processes, requiring specialized handling or processing methods to prevent cracking or damage.
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