Nickel and nickel alloys · Alloy 75 / Nicrofer 7520 / N06075 / 2.4951
Heat-Resistant Alloy 75 (Nimonic 75): Engineering Handbook
Engineering and Technical Review of Alloy 75 (UNS N06075)
| Supply Form | Marking | Main Standards | Analogues and Standardization |
|---|---|---|---|
| Sheet, plate, strip, bars, hexagonal bars, tubes, forged blanks | Alloy 75, Nicrofer 7520, Nimonic 75, VDM Alloy 75, UNS N06075 | ASTM B637; MSRR 7004, 7022, 7063, 7070, 7162, 7193, 7952 | W.Nr. 2.4951, 2.4630; DIN 17742, 17751, 17750, 17752, 17754; BS HR 203, 403, 3HR1, HR3, HR4, BS4HR 601; ISO NiCr20Ti |
Alloy 75, also known as Nimonic 75 (UNS N06075), is a heat-resistant nickel-chromium material alloyed with titanium. Its key operational properties are excellent resistance to high-temperature oxidation and high structural stability. These characteristics make it an indispensable structural material for components operating in aggressive gaseous environments at extreme temperatures, finding application in the aerospace industry and power generation.
Standard Chemical Composition of Alloy 75 (UNS N06075) in %
| C | 0,08-0,15 |
|---|---|
| Pb | <0,005 |
| S | <0,02 |
| Ti | 0,2-0,6 |
| Cu | <0,5 |
| Mn | <1,0 |
| Si | <1,0 |
| Fe | 4,0 |
| Co | <5,0 |
| Cr | 20,0 |
| Ni | 75,0 |
Mechanical Properties of Nicrofer 7520 Alloy at Room Temperature
| Tensile Strength | Yield Strength (0.2% offset) | Elongation (min) |
|---|---|---|
| 94,3 ksi | 39,2 ksi | 25% |
| 650 MPa | 270 MPa | 25% |
The alloy matrix is an austenitic Ni-Cr system with controlled titanium and carbon content. Such alloying provides a unique synergistic effect: high ductility for forming and outstanding heat resistance for operation. Key technological advantages of the material from EV Group China:
- Exceptional resistance to gas corrosion and oxidation in environments with high oxygen activity at temperatures up to 1100 °C.
- Low scaling rate during cyclic and static heating up to 1000 °C, ensuring dimensional stability of parts.
- Stability of strength characteristics and creep resistance under prolonged high-temperature loads.
- Absence of phase transformations leading to embrittlement, which guarantees long-term reliability and metallurgical stability of the structure.
Physical and Thermophysical Constants of Alloy 75
The material density under standard conditions (20°C) is 8.4 g/cm³.
| Melting Range | Specific Heat | Curie Temperature | Modulus of Elasticity | Coefficient of Linear Expansion (21-93 °C) | Thermal Conductivity | Electrical Resistivity |
|---|---|---|---|---|---|---|
| 1340-1380 °C | 445 J/kg*°C | 650 °C | 221 kN/mm² | 11,7 µm/m*°C | 12,2 W/m*°C | 109 µohm*m |
Critical technological note: contact of the alloy with sulfur, phosphorus, lead, and other low-melting metals must be avoided during processing and operation temperatures. These elements provoke the formation of eutectics along grain boundaries, leading to irreversible high-temperature embrittlement of the material.
Welding and Processing Technology
Alloy 75 demonstrates excellent weldability using standard methods, including argon arc welding (TIG/GTAW), gas metal arc welding (MIG/GMAW), and shielded metal arc welding (SMAW). To minimize the heat-affected zone and prevent overheating, pulsed welding modes with low heat input are recommended. Edge preparation before welding is mandatory and includes complete mechanical cleaning to a metallic luster to remove oxide films, scale, and any organic contaminants. Interpass temperature control is critical and should not exceed 120°C. Subsequent heat treatment of the welded joint for stress relief is generally not required.
Key Application Areas of Alloy 75
- Hot section components of gas turbine engines and installations: combustion chambers, flame tubes, power rings, exhaust gas systems.
- High-temperature fixtures for industrial furnaces, including muffles, retorts, conveyor belts, and fasteners for heat treatment.
- High-temperature shut-off and control valves, as well as springs and elastic elements operating at elevated temperatures.
- Structural components of nuclear reactor active zones and protective screens, where a combination of heat resistance and corrosion resistance is required.