Hangbo Alloy Group
Shanghai · Est. 2012
UNS N07520 — Precipitation-hardened Ni-Co-Cr superalloy for gas-turbine discs, shafts, blading, and high-temperature rotating components in the 760–927°C service range. Manufacturer & global supplier.
Udimet 520 (UNS N07520) is a precipitation-hardened, vacuum-melted nickel-cobalt-chromium superalloy developed for high-temperature structural service in the 760–927°C (1400–1700°F) range. It is the upgraded successor to Udimet 500, engineered to deliver a superior combination of high-temperature strength, creep resistance, low-cycle fatigue resistance, and fabricability for the most demanding rotating components of aircraft and industrial gas turbines.
The alloy's strength comes from gamma-prime [γ′ = Ni₃(Al,Ti)] precipitation hardening reinforced by solid-solution additions of cobalt, molybdenum, and tungsten. Compared with its predecessor, Udimet 520 trades some cobalt for higher molybdenum and a refined Al/Ti balance, which improves creep and stress-rupture resistance, thermal stability, and forgeability. Its primary applications are gas-turbine discs, shafts, spacers, and turbine blading, where long life under high stress and temperature is mandatory.
Udimet 520 is an austenitic, non-magnetic alloy with good oxidation and moderate hot-corrosion resistance. Hangbo Alloy Group supplies Udimet 520 as forged bar, billet, discs, rings, and gas-atomized powder, with full certification for aerospace and power-generation buyers seeking a dependable Udimet 520 supplier.
Hangbo Alloy Group manufactures and supplies Udimet 520 (UNS N07520) forged bar, billet, turbine discs, rings, and gas-atomized powder with full mill test reports and heat-treatment certification. Stock and made-to-order available.
Udimet 520 is precipitation-hardened by a high volume fraction of gamma-prime. The cobalt and molybdenum contents provide solid-solution strengthening and raise the gamma-prime solvus, broadening the useful precipitation window and improving creep resistance. The controlled carbon and boron levels strengthen grain boundaries, while ultra-low sulfur and phosphorus preserve hot ductility.
| Element | Standard / Limiting Range (wt%) | Typical Value | Role in the Alloy |
|---|---|---|---|
| Nickel (Ni) | Balance | ~55 | Austenitic FCC matrix, oxidation & corrosion resistance |
| Chromium (Cr) | 18.0 – 20.0 | 19.0 | Cr₂O₃ scale; oxidation & hot-corrosion resistance |
| Cobalt (Co) | 11.0 – 14.0 | 12.5 | Solid-solution strengthening; raises γ′ solvus |
| Molybdenum (Mo) | 5.50 – 7.00 | 6.0 | Solid-solution strengthening; creep resistance |
| Titanium (Ti) | 2.90 – 3.25 | 3.0 | γ′ former [Ni₃(Al,Ti)] |
| Aluminum (Al) | 1.80 – 2.30 | 2.0 | γ′ former; scale adhesion |
| Tungsten (W) | 0.80 – 1.20 | 1.0 | Solid-solution strengthening at high temperature |
| Carbon (C) | 0.020 – 0.060 | 0.04 | MC/M₂₃C₆ carbides; grain-boundary strength |
| Boron (B) | 0.004 – 0.010 | 0.006 | Grain-boundary strengthening |
| Iron (Fe) | ≤ 1.0 (residual) | 0.5 | Controlled low to preserve matrix |
| Silicon (Si) | ≤ 0.15 | 0.10 | Deoxidation; controlled for hot ductility |
| Manganese (Mn) | ≤ 0.15 | 0.10 | Deoxidation; sulfur control |
Note: Sulfur is typically ≤0.015% and phosphorus ≤0.015% (impurity control). The composition is normally procured to a producer/OEM specification such as Special Metals PDS 15125A1; the ranges above are typical published limiting values for wrought product.
Udimet 520 behaves as a typical high-strength nickel-base superalloy: moderate density, low thermal conductivity, and a thermal-expansion coefficient between those of stainless steels and cobalt-base alloys.
| Property | Value | Notes |
|---|---|---|
| Density | 8.21 g/cm³ (0.297 lb/in³) | Typical |
| Melting Range | 1260 – 1405 °C (2300 – 2560 °F) | Solidus – liquidus |
| Thermal Expansion (20–100°C) | ~13.5 × 10−6 /°C | Mean coefficient |
| Thermal Expansion (20–800°C) | ~14.8 × 10−6 /K | Mean coefficient |
| Thermal Conductivity | ~11.5 W/(m·K) at 100°C | Low; control heat input |
| Electrical Resistivity | ~1.25 μΩ·m | Typical |
| Modulus of Elasticity (RT) | ~200 – 210 GPa | Decreases with temperature |
| Magnetic Properties | Non-magnetic (austenitic FCC) | |
Properties below are typical minima for forged bar/disc stock in the standard solution-plus-aged condition. Actual values depend on product form, section size, and exact heat-treatment cycle.
| Property | Typical / Minimum Value | Condition |
|---|---|---|
| Tensile Strength (Rm) | ≥ 1250 MPa (≈180 ksi) | Aged |
| Yield Strength (Rp0.2) | ≥ 900 MPa (≈130 ksi) | Aged |
| Elongation (A) | ≥ 12% | Aged |
| Reduction of Area (Z) | ≥ 15% | Aged |
| Hardness | HRC 38 – 42 (≈300 – 340 HB) | Aged |
| Property | ~730°C (1350°F) | Notes |
|---|---|---|
| Tensile Strength | ~1000 – 1070 MPa | Typical aged bar |
| Yield Strength (Rp0.2) | ~730 – 830 MPa | Typical aged bar |
| Elongation | ~15% | Good ductility retained |
The 1000-hour rupture strength illustrates the alloy's creep capability across its service range (typical precipitation-hardened values from producer data):
| Temperature | 1000-h Rupture Strength |
|---|---|
| 649°C (1200°F) | ~585 MPa |
| 704°C (1300°F) | ~475 MPa |
| 760°C (1400°F) | ~345 MPa |
| 816°C (1500°F) | ~230 MPa |
| 871°C (1600°F) | ~150 MPa |
Udimet 520 requires a multi-step precipitation-hardening cycle to develop its optimum gamma-prime distribution:
Exact cycles follow the controlling specification (e.g., PDS 15125A1) and are adjusted for section size and component type. Vacuum or protective-atmosphere treatment is used to avoid surface oxidation on finished parts.
Udimet 520 is only moderately weldable and is sensitive to hot cracking. Where joining or rebuilding is required, GTAW (TIG) or electron-beam welding is used, typically on solution-treated material with controlled low-to-moderate heat input and preheat near 200°C. A full solution-plus-aging treatment after welding is required to restore properties. Matching-composition wire (ER Udimet 520) is preferred; procedure qualification is strongly recommended because welding experience with the alloy is limited.
Contact Hangbo Alloy Group for certified Udimet 520 forged bar, billet, turbine discs, rings, and gas-atomized powder. Competitive Udimet 520 price, fast mill lead times, full MTR and third-party inspection support.
Udimet 520 maintains useful oxidation and hot-corrosion resistance across its service temperature band:
Hangbo Alloy Group supplies Udimet 520 (UNS N07520) in the following product forms, produced by VIM (+ESR/VAR) melting for high purity and low gas content:
| Product Form | Typical Size / Condition |
|---|---|
| Forged Round Bar / Billet | Diameter 10 – 300 mm; solution-treated or fully heat-treated |
| Discs / Pancakes / Rings | Diameter 200 – 1200 mm; forged, heat-treated, machined |
| Hot-Rolled Bar | Diameter 8 – 120 mm |
| Gas-Atomized Powder | 15 – 53 µm (AM/HIP), 45 – 150 µm (PM) |
| Welding Wire (ER Udimet 520) | Diameter 0.8 – 2.4 mm; spools / cut lengths |
| Precision-Machined Components | To customer drawing; discs, rings, flanges |
All products are supplied with EN 10204 Type 3.1 material certificates, including chemical analysis, room- and high-temperature mechanical tests, and ultrasonic/penetrant inspection where specified.
| Standard / Designation | Description |
|---|---|
| UNS N07520 | Unified Numbering System designation for Udimet 520 |
| Werkstoff-Nr. | — (no EN/DIN W.Nr. is published for this grade) |
| Special Metals PDS 15125A1 | Producer material specification / data sheet for UDIMET alloy 520 |
| OEM gas-turbine specs | Procured to GE / P&W-type proprietary purchase orders |
| Product form | Forged bar, ring, disc, billet to customer/OEM specification |
| Heat treatment | Solution + two-stage aging per PDS 15125A1 |
| Property | Udimet 520 | Udimet 500 | Waspaloy | Inconel 718 |
|---|---|---|---|---|
| UNS | N07520 | N07500 | N07001 | N07718 |
| Nominal Co % | 11 – 14 | 15 – 20 | 12 – 15 | ≤ 1 |
| Nominal Cr % | 18 – 20 | 18 – 19 | 18 – 21 | 17 – 21 |
| Nominal Mo % | 5.5 – 7.0 | 3.0 – 5.0 | 3.5 – 5.0 | 2.8 – 3.3 |
| Strengthening | γ′ | γ′ | γ′ + B/Zr | γ″ + γ′ |
| Service temp | 760 – 927°C | 650 – 870°C | up to ~870°C | up to ~650°C |
| RT tensile (typ.) | ≥1250 MPa | ~1200 MPa | ~1200 MPa | ~1275 MPa |
| Weldability | Moderate | Moderate | Moderate | Good |
| Primary use | Turbine discs/shafts | Turbine discs | Turbine discs/rings | Turbine discs/rings |
Selection guide: Choose Udimet 520 when service temperatures exceed the practical limit of Inconel 718 (≈650°C) and when maximum creep and stress-rupture strength are needed for discs and shafts. Choose Udimet 500 for slightly lower-temperature disc service, Waspaloy for rings and cases needing good hot-corrosion resistance, and Inconel 718 when weldability and fabricability dominate.
Udimet 520 (UNS N07520) is a precipitation-hardened nickel-cobalt-chromium superalloy developed for high-temperature structural service in the 760-927°C (1400-1700°F) range. It is strengthened by gamma-prime [Ni3(Al,Ti)] precipitation plus solid-solution additions of cobalt, molybdenum, and tungsten. Its primary use is gas-turbine discs, shafts, blading, and other rotating hot-section components in aircraft and industrial gas turbines.
Typical limiting composition of Udimet 520 (UNS N07520): Nickel balance; Chromium 18.0-20.0%; Cobalt 11.0-14.0%; Molybdenum 5.50-7.00%; Titanium 2.90-3.25%; Aluminum 1.80-2.30%; Tungsten 0.80-1.20%; Carbon 0.020-0.060%; Boron 0.004-0.010%; with iron, silicon, and manganese as controlled trace residuals (S and P each typically ≤0.015%).
In the standard precipitation-hardened condition, Udimet 520 typically delivers room-temperature tensile strength ≥1250 MPa (≈180 ksi), yield strength ≥900 MPa (≈130 ksi), elongation ≥12%, reduction of area ≥15%, and hardness about HRC 38-42 (≈300-340 HB). At 730°C (1350°F) the alloy still retains roughly 1000-1070 MPa tensile and 730-830 MPa yield strength with good ductility.
Udimet 520 has a density of about 8.21 g/cm³ (0.297 lb/in³). Its melting range is approximately 1260-1405°C (2300-2560°F). The thermal expansion coefficient is about 13.5 ×10⁻⁶/°C at 20-100°C and roughly 14.8 ×10⁻⁶/K over 20-800°C. It is an austenitic, non-magnetic alloy.
Udimet 520 is given a multi-step precipitation-hardening treatment: solution treat near 1080°C (1975°F) followed by rapid air or oil quench, then a two-stage age — typically 845°C (1550°F) for several hours and 760°C (1400°F) for about 16 hours, each air cooled. This produces a fine, uniform distribution of gamma-prime that provides maximum strength and creep resistance. Exact cycles follow the producer's specification (e.g., PDS 15125A1).
Udimet 520 is engineered for continuous service in the 760-927°C (1400-1700°F) range. It retains useful strength and oxidation resistance up to about 870°C (1600°F) and is not recommended for long-term use above roughly 950°C, where gamma-prime coarsening reduces strength.
Typical 1000-hour rupture strengths for precipitation-hardened Udimet 520 are about 585 MPa at 649°C, 475 MPa at 704°C, 345 MPa at 760°C, 230 MPa at 816°C, and 150 MPa at 871°C. These values make it suitable for high-stress turbine-disc and shaft service, with creep and stress-rupture resistance comparable to Waspaloy and René 41.
Udimet 520 is used for the most demanding rotating and static hot-section components of gas turbines: turbine discs, compressor discs, shafts, spacers, turbine blades and buckets, high-strength fasteners, and rings. It serves both aerospace engines and industrial/utility gas turbines where long life under high temperature and stress is required.
Both are gamma-prime strengthened nickel-cobalt superalloys, but Udimet 520 trades some cobalt for higher molybdenum (5.5-7.0% vs 3.0-5.0%) and a somewhat different Al/Ti balance. The result is improved creep and stress-rupture resistance, better high-temperature stability, and generally better fabricability than Udimet 500, while retaining comparable room-temperature strength. Udimet 520 is the more modern, upgraded grade for turbine-disc service.
Versus Waspaloy, Udimet 520 has higher molybdenum and a comparable cobalt level, giving it slightly higher strength and good hot-corrosion behaviour. Versus Inconel 718, Udimet 520 has a higher allowable service temperature (718 is typically used to about 650°C) and greater creep strength, while 718 offers easier fabrication and weldability. Udimet 520 is selected when service temperatures exceed the practical limit of 718.
Udimet 520 can be joined by GTAW (TIG) and electron-beam welding, but it is considered only moderately weldable and is sensitive to hot cracking. Welding is normally done in the solution-treated condition with controlled, low-to-moderate heat input and preheat around 200°C, followed by a full solution-plus-aging heat treatment to restore properties. Matching-composition wire (ER Udimet 520) is preferred. Many turbine-disc applications avoid welding and use forged monolithic parts.
Hangbo Alloy Group supplies Udimet 520 as forged round bar and billet (diameter roughly 10-300 mm), forged discs, rings and pancake forgings, hot-rolled bar, precision machined rings and flanges, gas-atomized powder for HIP / additive manufacturing, and matching welding wire (ER Udimet 520). All products are supplied with full mill test reports and can be delivered in the solution-treated or fully heat-treated condition.
Udimet 520 is identified by UNS N07520. It is not assigned a Werkstoff-Nr. (no EN/DIN number is published) and is most commonly procured to proprietary OEM and producer specifications such as Special Metals PDS 15125A1 and gas-turbine OEM material specs (GE, Pratt & Whitney-type). It is supplied as forged bar, ring, disc and billet to customer/OEM purchase orders with heat treatment per PDS 15125A1.
Udimet 520 is a premium aerospace/power-generation superalloy. Typical market pricing ranges from roughly $45-90/kg for forged bar and billet, higher for discs, rings, and precision-machined components, and $80-140/kg for gas-atomized powder, depending on section size, certification level, and nickel/cobalt/molybdenum market conditions. Lead times are typically 6-14 weeks for standard forged product and 10-20 weeks for discs, rings, or certified aerospace lots. Contact serena@hangboalloy.com for a competitive quote.
