Summary
UNS N07500 is a precipitation-hardening nickel-chromium-cobalt superalloy sold commercially as Udimet 500 (U-500). Its nominal chemistry is 18.5% cobalt, 18% chromium, 4% molybdenum, 3% titanium and 3% aluminium with nickel as the balance. Solution treated and double aged, it typically reaches 1310 MPa tensile strength, 840 MPa 0.2% proof strength and 20% elongation at room temperature. It is specified for turbine discs and rings, valve internals, pump shafts and other parts that have to hold strength at temperature.
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China, produces UNS N07500 as seamless rolled rings, discs, shafts, flanges, sleeves, bushings, tube sheets and round bars to ASTM B637. Parts are made to customer drawing, ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388, and shipped worldwide. Quotations are issued within 24 hours at sales@steelforgepieces.com.
UNS N07500 at a glance
| UNS number | N07500 |
|---|---|
| Common names | Udimet 500, U-500, Udimet alloy 500, alloy 500 superalloy |
| Alloy family | Precipitation-hardening (gamma-prime) nickel-chromium-cobalt superalloy |
| Supply specification | ASTM B637 |
| Melting route | EAF + VOD, then ESR remelt |
| Delivery condition | Solution treated and double aged, rough machined to agreed allowance |
| Density, typical | 8.02 g/cm3 (0.290 lb/in3) |
| Melting range, typical | 1300 to 1395 °C |
| Related grades | Waspaloy (N07001), Rene 41 (N07041), Inconel X-750 (N07750), Incoloy 901 |
| Manufacturer | Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu, China |
Physical values are typical published figures for this alloy family and are given for design guidance. Acceptance is governed by the certified values on the mill certificate for the heat supplied.
What UNS N07500 is
UNS N07500 belongs to the group of nickel superalloys that carry both high cobalt and a high combined titanium plus aluminium content. That combination precipitates a large volume fraction of gamma prime, the ordered Ni3(Al,Ti) phase that holds strength at high temperature. Molybdenum adds solid-solution strength, chromium provides oxidation resistance, and trace boron and zirconium strengthen the grain boundaries.
The same gamma prime narrows the forging window. Working UNS N07500 needs close control of soak temperature, strain rate and finishing temperature, so the grade is normally bought from open-die shops that run superalloys regularly. Forging history sets the grain size, and grain size decides whether a part passes ultrasonic testing.
Chemical composition
NickelCobalt ChromiumMolybdenum AluminiumTitanium C, Fe, B, Zr
| Element | Nominal, wt % | Function |
|---|---|---|
| Nickel (Ni) | Balance, approx. 53 | Matrix and host for the gamma-prime precipitate |
| Cobalt (Co) | 18.50 | Raises the gamma-prime solvus and hot strength |
| Chromium (Cr) | 18.00 | Oxidation and hot-corrosion resistance |
| Molybdenum (Mo) | 4.00 | Solid-solution strengthening |
| Aluminium (Al) | 3.00 | Forms gamma prime, Ni3(Al,Ti) |
| Titanium (Ti) | 3.00 | Forms gamma prime and raises the precipitate volume |
| Carbon (C) | 0.08 | Carbide formation at grain boundaries |
| Iron (Fe) | below 1.00 | Residual |
| Boron (B) and zirconium (Zr) | Trace | Grain-boundary strengthening, typical micro-additions |
Nominal chemistry for reference. Heat-specific analysis is reported on the EN 10204 3.1 certificate that ships with every UNS N07500 forging from Jiangyin Jiangnan Metal Co., Ltd.
Mechanical properties
The figures below are typical room-temperature values for UNS N07500 forgings in the solution-treated and aged condition. Section size, forging reduction and the exact ageing cycle all move them, so acceptance limits should be agreed at enquiry stage and written into the order.
| Property | Metric | Imperial |
|---|---|---|
| Ultimate tensile strength | 1310 N/mm2 (MPa) | approx. 190 ksi |
| 0.2% proof (yield) strength | 840 N/mm2 (MPa) | approx. 122 ksi |
| Elongation (5d) | 20 % | 20 % |
| Work-hardening behaviour | Pronounced. The alloy hardens quickly under the tool and stays gummy, unlike steel. | |
Typical values for reference, not a guarantee. Tensile testing is carried out on each heat-treatment lot and reported on the certificate. Elevated-temperature, stress-rupture and impact testing can be added on request.
Heat treatment
Udimet 500 is normally given a three-stage or four-stage cycle. The three-stage route is the one used to develop maximum high-temperature properties in forged material: one solution treatment followed by a double age.
The 1080 °C / 4 h and 840 °C / 24 h stages are the cycle Jiangyin Jiangnan Metal Co., Ltd. runs as standard for UNS N07500 forgings. Where a customer specification calls for a four-stage cycle or a different ageing schedule, the furnaces are run to that specification and the charts are supplied with the certificate.
How we forge UNS N07500
The route below is what a UNS N07500 order runs through at our plant in Jiangyin. Each step is recorded, so a finished ring can be traced back to its ingot.
- Melt and refine. Electric arc furnace with vacuum oxygen decarburisation, then an electroslag remelt (EAF + VOD + ESR) to control segregation and inclusion content.
- Cog the ingot. The ESR ingot is soaked into the forging window and cogged on the open-die press to break down the as-cast structure and reach the agreed reduction ratio.
- Forge or roll to shape. Upset, punch, then either open-die forge discs, shafts and blocks, or ring-roll seamless rolled rings on the ring mill.
- Solution treat and age. 1080 °C / 4 h air cool, then 840 °C / 24 h air cool, with calibrated furnace charts.
- Rough machine. Cut back to the agreed stock allowance so ultrasonic testing sees a representative surface.
- Test and certify. Chemistry, mechanical tests and ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, then EN 10204 3.1 certification, or 3.2 with a third party such as SGS, BV, TUV or Lloyd's.
Product forms and size range
Everything is made to drawing. There is no catalogue stock list for UNS N07500. Send the geometry and the quantity, and the forging weight comes back with the price.
| Form | Typical range | Notes |
|---|---|---|
| Seamless rolled rings and forged rings | OD 100 to 3000 mm, height to 800 mm | Ring-rolled, wall from 20 mm |
| Discs, blanks, tube sheets | Diameter to 1500 mm | Solid or trepanned |
| Shafts, eccentric shafts, spindles | Diameter 60 to 800 mm, length to 6000 mm | Stepped shafts machined to drawing |
| Flanges, hubs, valve bodies and seats | To drawing | Weld-neck, blind and special profiles |
| Sleeves, bushings, hollow bars | To drawing | Bored and rough machined |
| Round bars, blocks, nozzles, gear blanks | To drawing | Cut to length |
| Single-piece forged weight | 5 kg to 6000 kg | Larger pieces on enquiry |
| Minimum order | 1 piece | Prototypes and single spares accepted |
Where UNS N07500 forgings are used
Turbines and rotating equipment
Discs, rings, spindles, gear blanks and bars for gas turbines, industrial compressors, power transmission and gearboxes, where strength has to survive the running temperature.
Valves and flow control
Valve stems, seat rings, blocks and bodies for ball, gate, globe, check and plug valves in high-temperature or aggressive service.
Pumps
Forged shafts and sleeves for chemical pumps and plunger pumps that see both load and corrosive media.
Oil, gas and subsea
Bushings, sleeves, discs and blocks for wellhead and Christmas tree assemblies, subsea and deepwater production systems, and nitrogen and air generation packages.
Pressure equipment
Tube sheets, nozzles, forged flanges and pipe sections for shell and tube heat exchangers, air receivers, columns, towers, silos and preheaters.
Heavy and process machinery
Eccentric shafts, rolls, wheels, manifolds and crankshafts for cement and sugar mills, mixers, shipbuilding, pulp and paper, and pharmaceutical process units.
Machining and fabrication notes
UNS N07500 cuts broadly like Monel 400 and Monel K-500, but at a much higher strength level. It work-hardens under the tool and stays gummy in a way steel does not:
- Rigid setup, minimum overhang, and the heaviest tool that fits the feature.
- Sharp positive-rake tooling, replaced before the edge rounds. A dull edge burnishes and hardens the surface.
- Low surface speed with a positive, uninterrupted feed. Never let the tool rub or dwell in the cut.
- Flood coolant delivered at the cutting edge rather than behind it.
- Leave stock for a finishing pass that cuts under the work-hardened layer left by roughing.
We supply UNS N07500 forgings black, rough machined to an agreed allowance, or finish machined to your drawing. On this alloy the finish-machined option is often cheaper once tooling cost is counted.
Testing, inspection and certification
| Test | Standard | Scope |
|---|---|---|
| Ultrasonic testing | EN 10228-3, SEP 1921, ASTM A388 | Standard on every forging, acceptance class to order |
| Chemical analysis | Per ASTM B637 | Standard, per heat |
| Tensile testing | ASTM E8 or ISO 6892 | Standard, per heat-treatment lot |
| Hardness | ASTM E18 or E10 | Standard |
| Dye penetrant | ASTM E165 | On request. PT is used because the alloy is non-magnetic |
| Grain size and microstructure | ASTM E112 | On request |
| Elevated temperature and stress rupture | ASTM E21, ASTM E139 | On request |
| Certification | EN 10204 3.1 or 3.2 | 3.1 standard, 3.2 third-party inspection available |
UNS N07500 compared with related grades
| Grade | Cr | Co | Mo | Ti | Al | UTS, typical |
|---|---|---|---|---|---|---|
| UNS N07500 (Udimet 500) | 18 | 18.5 | 4 | 3.0 | 3.0 | approx. 1310 MPa |
| Waspaloy (N07001) | 19 | 13.5 | 4.3 | 3.0 | 1.4 | approx. 1275 MPa |
| Rene 41 (N07041) | 19 | 11 | 10 | 3.1 | 1.5 | approx. 1400 MPa |
| Inconel X-750 (N07750) | 15.5 | n/a | n/a | 2.5 | 0.7 | approx. 1200 MPa |
Nominal values for orientation only. Udimet 500 carries the most cobalt and the most aluminium of the four, so it holds the most gamma prime and the most hot strength, and it is also the hardest of the four to forge and machine. Rene 41 uses molybdenum instead, and Inconel X-750 is the easier, lower-strength option.
Request a quotation for UNS N07500 forgings
Send a drawing or a rough size list. A price, a forging weight and a lead time come back within 24 hours. Typical lead time is 25 to 45 days depending on size, heat treatment and testing scope.
- Drawing, or rough dimensions (OD x ID x height, or diameter x length)
- Quantity, and whether the item repeats
- Delivery condition: black, rough machined, or finish machined
- Specification and acceptance class for ultrasonic testing
- Certificate type: EN 10204 3.1, or 3.2 with a named third party
Frequently asked questions
What is UNS N07500?
UNS N07500 is a precipitation-hardening nickel-chromium-cobalt superalloy, sold under the trade name Udimet 500 or U-500. Its nominal composition is about 18.5% cobalt, 18% chromium, 4% molybdenum, 3% titanium and 3% aluminium with nickel as the balance. The titanium and aluminium form the gamma-prime precipitate that carries the high-temperature strength, and the alloy is normally supplied in the solution-treated and double-aged condition.
What is UNS N07500 equivalent to?
UNS N07500 is the unified numbering designation for the alloy sold as Udimet 500, also written U-500, Udimet alloy 500 or alloy 500 superalloy. Bars, forgings and forging stock in this grade are covered by ASTM B637. It belongs to the same family as Waspaloy (UNS N07001) and Rene 41 (UNS N07041) but carries more cobalt than Waspaloy.
What is the chemical composition of UNS N07500?
The nominal chemistry of UNS N07500 is carbon 0.08%, cobalt 18.50%, chromium 18.00%, molybdenum 4.00%, aluminium 3.00%, titanium 3.00%, iron below 1.00% and nickel as the balance, with small boron and zirconium additions for grain-boundary strength. Certified values for each heat are reported on the EN 10204 3.1 mill certificate.
What are the mechanical properties of UNS N07500?
In the solution-treated and aged condition, UNS N07500 forgings typically reach 1310 MPa tensile strength, 840 MPa 0.2% proof strength and 20% elongation measured over five diameters at room temperature. These are typical values for reference. Acceptance is governed by the values on the mill certificate for the delivered heat.
What is the heat treatment for UNS N07500 forgings?
Udimet 500 is normally given a three-stage or four-stage cycle. The three-stage route used for forged material is a solution treatment at 1080 °C for 4 hours followed by air cooling, then ageing at 840 °C for 24 hours followed by air cooling. A further lower-temperature ageing stage can be added when maximum high-temperature strength is required.
Is UNS N07500 difficult to machine?
Yes. UNS N07500 work-hardens quickly during cutting and stays gummy in a way that carbon and stainless steels do not. It machines broadly like Monel 400 and Monel K-500 but at a higher strength level, so it needs rigid setups, sharp positive-rake tooling, low surface speeds with a heavy positive feed, and generous coolant so the tool never dwells in the cut.
Which standard covers UNS N07500 forgings?
Jiangyin Jiangnan Metal Co., Ltd. supplies UNS N07500 forging material to ASTM B637, the specification for precipitation-hardening nickel alloy bars, forgings and forging stock for moderate or high temperature service. Ultrasonic testing follows EN 10228-3, SEP 1921 or ASTM A388, and certification is issued to EN 10204 3.1 or EN 10204 3.2.
What forms and sizes of UNS N07500 forgings are available?
Jiangyin Jiangnan Metal Co., Ltd. produces UNS N07500 as seamless rolled rings, forged rings, discs, blanks, shafts, eccentric shafts, flanges, sleeves, bushings, tube sheets, hollow bars, round bars, blocks and nozzles. Rings are rolled up to about 3000 mm outside diameter and single forged pieces run from roughly 5 kg to 6000 kg, all made to customer drawing.
Who supplies UNS N07500 open-die forgings?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China that manufactures UNS N07500 (Udimet 500) forgings to customer drawings and ships worldwide. Enquiries go to sales@steelforgepieces.com or +86-189-2135-9659, and quotations are issued within 24 hours of receiving a drawing or size list.
How do I get a quotation for UNS N07500 forgings?
Send the drawing or the rough size, the quantity, the delivery condition and any specification or testing requirement to sales@steelforgepieces.com. Jiangyin Jiangnan Metal Co., Ltd. replies with a price, a forging weight and a lead time within 24 hours. Typical lead time for UNS N07500 forgings is 25 to 45 days depending on size, heat treatment and testing scope.
What is the difference between UNS N07500 and Waspaloy?
Both are gamma-prime strengthened nickel-cobalt superalloys. UNS N07500 (Udimet 500) carries about 18.5% cobalt and 3% aluminium against roughly 13.5% cobalt and 1.4% aluminium in Waspaloy (UNS N07001). The higher aluminium gives Udimet 500 a larger gamma-prime volume fraction and more high-temperature strength, at the cost of a narrower forging window and harder machining.
What is UNS N07500 used for?
UNS N07500 forgings are used for gas turbine discs, rings and shafts, valve stems, seats and bodies in high-temperature service, chemical and plunger pump shafts, subsea and wellhead components, compressor and gear-box parts, and pressure-equipment items such as tube sheets, nozzles and flanges that must hold strength at temperature.
About the manufacturer
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China. We forge rings, seamless rolled rings, discs, shafts, flanges, sleeves, bushings and bars to customer drawing in carbon steel, alloy steel, tool steel, stainless steel and nickel-base superalloys, including UNS N07500 (Udimet 500), Waspaloy, Inconel, Incoloy, Hastelloy and Monel grades. Orders ship worldwide with EN 10204 3.1 or 3.2 certification.
- CompanyJiangyin Jiangnan Metal Co., Ltd.
- TypeOpen-die forging factory and forged component manufacturer
- AddressNo.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Post code214423
- Phone+86-189-2135-9659 (0086-189-2135-9659)
- Emailsales@steelforgepieces.com
- Websitewww.steelforgepieces.com
- Ships toWorldwide
Cite this page
Jiangyin Jiangnan Metal Co., Ltd. (2026). UNS N07500 (Udimet 500) forgings: composition, properties, heat treatment and available forms. Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/UNS-N07500.html