Nickel-Iron Alloy 4750, also known as High Perm 49 (UNS K94840), is a 48% nickel-iron alloy that combines high saturation flux density (approximately 16,000 gauss / 1.6 tesla) with high magnetic permeability and low core loss. This alloy offers the highest saturation flux density among nickel-iron alloys, making it a versatile choice for magnetic applications. Typical applications include laminated cores for instrument transformers, magnetic shields, and cores for electronic and communications devices where its high permeability at low magnetizing forces can greatly increase device efficiency.
1. Product Specifications & Physical DataAlloy 4750 is a controlled-expansion nickel-iron soft magnetic alloy designed for applications requiring high saturation induction combined with good permeability. To achieve maximum softness and optimum magnetic and electrical properties, the alloy should be annealed in a dry hydrogen atmosphere at 1177°C (2150°F) for 2-4 hours, followed by controlled cooling. Available Forms: Bar, wire, sheet, and strip . Specifications: UNS K94840, ASTM A753 Alloy 2 .
| Chemical Composition (Weight %) | Alloy 4750 Specification |
|---|
| Nickel (Ni) | 47.0 - 49.0 | | Iron (Fe) | Balance | | Manganese (Mn) | 0.30 - 0.60 | | Silicon (Si) | 0.15 - 0.30 | | Carbon (C) | 0.05 max. | | Sulfur (S) | 0.01 max. | | Chromium (Cr) | 0.25 max. | | Molybdenum (Mo) | 0.10 max. | | Cobalt (Co) | 0.10 max. | | Titanium (Ti) | 0.10 max. | | Aluminum (Al) | 0.10 max. |
| Physical Properties | Metric | Imperial |
|---|
| Density | 8.18 g/cm³ | 0.295 lb/in³ | | Melting Range | 1427°C | 2600°F | | Curie Temperature | 449 - 499°C | 840 - 930°F | | Specific Heat Capacity | 0.1200 BTU/lb/°F | 502 J/kg·K | | Thermal Conductivity | 13.0 W/m·K | 90.2 BTU·in/hr·ft²·°F | | Electrical Resistivity | 48.2 µΩ·cm | 290 ohm-cir-mil/ft | | Temp Coefficient of Resistance | 20.0 × 10⁻⁴ /°F | 36.0 × 10⁻⁴ /°C |
| Modulus of Elasticity | Value (ksi) | Value (GPa) |
|---|
| Annealed (871°C) - Tension | 22.0 × 10³ | 152 GPa | | Annealed (871°C) - Torsion | 7.60 × 10³ | 52 GPa | | Cold Drawn - Tension | 24.0 × 10³ | 165 GPa | | Cold Drawn - Torsion | 7.80 × 10³ | 54 GPa | | Hydrogen Annealed (1177°C) - Tension | 22.5 × 10³ | 155 GPa | | Hydrogen Annealed (1177°C) - Torsion | 7.50 × 10³ | 52 GPa |
| Mechanical Properties (Annealed) | Metric | Imperial |
|---|
| Tensile Strength (min.) | 450 MPa | 65 ksi | | Yield Strength (0.2% offset) | 275 MPa | 40 ksi | | Elongation (min.) | 25% | 25% | | Hardness (Rockwell B) | 70 - 80 | 70 - 80 |
| Magnetic Properties (Hydrogen Annealed) | Value | Unit |
|---|
| Saturation Flux Density (Bs) | 1.6 T | 16,000 gauss | | Maximum Permeability (μmax) | 60,000 - 80,000 | — | | Coercive Force (Hc) | 0.3 - 0.5 Oe | 24 - 40 A/m | | Remanence (Br) | 0.6 - 0.8 T | 6,000 - 8,000 gauss |
2. FabricationHydrogen Annealing: 1177°C (2150°F) × 2-4 hours in dry hydrogen atmosphere, followed by furnace cool at 100-200°F per hour to 427°C (800°F), then any rate; essential for maximum softness and optimum magnetic properties . Process Annealing: 871°C (1600°F) for intermediate processing; relieves cold work stresses . Hot Working: 1093-1177°C (2000-2150°F); reheat as necessary . Cold Working: Good formability; can be cold rolled, drawn, and stamped . Machining: Similar to austenitic stainless steels; requires sharp tools and adequate lubrication . Welding: Not typically welded; magnetic properties are sensitive to thermal exposure.
3. ApplicationsInstrument Transformers: Laminated cores for current and voltage transformers requiring high saturation and good accuracy Magnetic Shields: Shielding for sensitive electronic equipment, CRT shields, MRI room shielding Communications Devices: Cores for inductors, chokes, and filters where high permeability at low excitation is beneficial Power Transformers: Small power transformers requiring high saturation flux density Relays & Actuators: Magnetic circuits for relays, solenoids, and magnetic actuators Aerospace Components: Magnetic components for avionics and flight control systems Medical Devices: Magnetic shielding for medical imaging equipment
Contact ZYTC Alloy for certified Nickel-Iron Alloy 4750 / High Perm 49 (UNS K94840) with complete traceability, technical datasheets, and competitive pricing. Available in bar, wire, sheet, and strip for magnetic core and shielding applications. Email: daisy@zytcsteel.com WhatsApp/WeChat: +86 17335753350 |
