Nickel Alloy Forgings · Material Data Sheet
Alloy 725 (UNS N07725) Forgings
Forged rings, seamless rolled rings, flanges, round bars, shafts, discs, sleeves, bushings and tube sheets in age-hardenable Alloy 725, manufactured to ASTM B564.
- UNS Number
- N07725
- Alloy Type
- Ni-Cr-Mo-NbAge-hardenable
- Min. Tensile
- 965 MPa140 ksi
- Min. 0.2% Yield
- 827 MPa120 ksi
- Min. Elongation
- 20 %
- Density
- 8.31 g/cm³0.300 lb/in³
- Forging Standard
- ASTM B564
- Melting Route
- EAF + VOD + ESR
Alloy 725 (UNS N07725) is an age-hardenable nickel-chromium-molybdenum-niobium superalloy. It holds the corrosion resistance of Alloy 625 at roughly twice the strength. Strength comes from precipitation of the gamma double-prime phase during ageing rather than from cold work, so heavy forged sections develop uniform properties through the wall.
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin City, Jiangsu Province, China, manufactures Alloy 725 forged rings, flanges, bars, shafts, discs and tube sheets to ASTM B564, supplied solution treated and double aged with EN 10204 3.1 or 3.2 certification.
§ 01
What Is Alloy 725?
Alloy 725 is a nickel-based superalloy covered by UNS number N07725. It runs 55 to 59 percent nickel, 19 to 22.5 percent chromium, 7 to 9.5 percent molybdenum and 2.75 to 4.0 percent niobium, with iron as the balance. That matrix chemistry sits close to Alloy 625, so the alloy holds the same resistance to chloride pitting, crevice corrosion and stress-corrosion cracking.
The difference between the two alloys is strength. Alloy 625 is solid-solution strengthened and ships annealed at 414 MPa minimum yield. Alloy 725 carries enough niobium and titanium to precipitate the gamma double-prime phase (γ″, Ni3Nb) during a two-step ageing cycle, which lifts minimum yield strength to 827 MPa. Corrosion performance is unaffected. Since the strengthening comes from heat treatment and not from cold work, a 600 mm forged section develops the same properties as a 60 mm bar. That is the reason Alloy 725 is specified for large subsea and wellhead components.
Alloy 725 is used for sour service in oil and gas production, where a part has to carry load in wet H2S. The alloy is listed in NACE MR0175 / ISO 15156-3, and API 6ACRA covers age-hardened Alloy 725 for oilfield equipment.
INCONEL is a registered trademark of Special Metals Corporation. Jiangyin Jiangnan Metal Co., Ltd. is an independent forging manufacturer and is not affiliated with or licensed by Special Metals Corporation. The name Inconel 725 appears on this page only to identify the generic alloy UNS N07725.
§ 02
Chemical Composition of Alloy 725
Chemical composition limits for Alloy 725 (UNS N07725) in weight percent, as supplied by Jiangyin Jiangnan Metal Co., Ltd. Every heat ships with a mill certificate reporting the actual ladle analysis.
| Element | Ni | Cr | Mo | Nb | Ti | Al | Fe | C | Mn | Si | P | S |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min % | 55.00 | 19.00 | 7.00 | 2.75 | 1.00 | – | Bal. | – | – | – | – | – |
| Max % | 59.00 | 22.50 | 9.50 | 4.00 | 1.70 | 0.35 | Bal. | 0.03 | 0.35 | 0.20 | 0.015 | 0.010 |
Iron is the balance. Niobium may be reported as Nb + Ta depending on the governing specification. Limits follow ASTM B564 and ASTM B805 for UNS N07725. Confirm the edition against your purchase specification.
§ 03
Mechanical Properties of Alloy 725 Forgings
Alloy 725 forgings ship in the solution treated and double aged condition. Minimum room temperature properties for forged product manufactured by Jiangyin Jiangnan Metal Co., Ltd. are listed below.
| Property | Metric | Imperial |
|---|---|---|
| Ultimate tensile strength | 965 MPa min | 140 ksi min |
| 0.2 % offset yield strength | 827 MPa min | 120 ksi min |
| Elongation in 4D | 20 % min | 20 % min |
| Hardness | Typically 32 to 40 HRC | Per governing specification |
Hardness acceptance limits for sour service are set by NACE MR0175 / ISO 15156-3 and by the equipment specification such as API 6ACRA, and depend on product form, section size and service environment. Confirm limits against the current edition before ordering. Impact testing, hardness banding and elevated temperature tensile testing can be added to any order.
Physical properties
| Property | Value |
|---|---|
| Density | 8.31 g/cm³ (0.300 lb/in³) |
| Melting range | 1271 to 1343 °C (2320 to 2450 °F) |
| Modulus of elasticity, 20 °C | Approx. 204 GPa (29.6 × 10&sup6; psi) |
| Magnetic response | Non-magnetic in the aged condition |
Physical property values are typical and given for design guidance. They are not acceptance criteria.
§ 04
Melting Route and Heat Treatment
Jiangyin Jiangnan Metal Co., Ltd. sources Alloy 725 melted by the EAF + VOD + ESR route. Electric arc melting is followed by vacuum oxygen decarburisation to hold carbon under the 0.03 percent limit, then electroslag remelting to refine the ingot structure and control non-metallic inclusions. The ESR step is what makes the ultrasonic cleanliness levels asked for on subsea components achievable.
Typical heat treatment cycle
- Solution treatment. Hold at approximately 1038 °C (1900 °F), then quench or cool rapidly.
- First age. Hold at approximately 732 °C (1350 °F) for 8 hours.
- Controlled furnace cool. Cool at a controlled rate to approximately 621 °C (1150 °F).
- Second age. Hold at approximately 621 °C (1150 °F) for 8 hours, then air cool.
Times and temperatures are typical for Alloy 725 and are adjusted for section size and for the properties required by the governing specification. Solution treatment and both ageing steps run as one controlled sequence. Furnace charts are available on request.
§ 05
Alloy 725 vs Alloy 625 vs Alloy 718
These three nickel alloys are regularly compared against each other. Alloy 625 is chosen for corrosion resistance and formability, Alloy 718 for maximum strength in a less aggressive environment, and Alloy 725 where a part needs high strength and 625-class corrosion resistance at the same time.
| Characteristic | Alloy 725 (N07725) | Alloy 625 (N06625) | Alloy 718 (N07718) |
|---|---|---|---|
| Strengthening mechanism | Age hardening (γ″) | Solid solution | Age hardening (γ″) |
| Condition compared | Solution treated + aged | Annealed | Solution treated + aged |
| Min. tensile strength | 965 MPa (140 ksi) | 827 MPa (120 ksi) | 1275 MPa (185 ksi) |
| Min. 0.2% yield strength | 827 MPa (120 ksi) | 414 MPa (60 ksi) | 1034 MPa (150 ksi) |
| Chromium | 19.0 to 22.5 % | 20.0 to 23.0 % | 17.0 to 21.0 % |
| Molybdenum | 7.0 to 9.5 % | 8.0 to 10.0 % | 2.8 to 3.3 % |
| Iron | Balance | 5.0 % max | Balance, approx. 18 % |
| Corrosion resistance | Very high | Very high | Moderate |
| Typical application | Subsea hangers, high-strength sour service | Cladding, bellows, chemical process | Turbine discs, oilfield equipment |
Values are typical minimums for the conditions noted and vary with specification, product form and section size. Confirm against the governing purchase specification.
§ 06
Alloy 725 Forged Product Forms and Size Range
Jiangyin Jiangnan Metal Co., Ltd. manufactures Alloy 725 forgings to drawing, to standard dimensions, or as rough machined blanks with an agreed machining allowance. The table covers routine production. Ask about anything outside it.
| Product form | Typical size range | Typical use |
|---|---|---|
| Seamless rolled rings | OD 200 to 2500 mm, wall 30 to 400 mm, height ≤ 800 mm | Hanger bodies, valve seats, connectors |
| Forged flanges | OD ≤ 2000 mm, thickness ≤ 500 mm | Wellhead, pressure vessel, piping |
| Forged round bars | Ø 50 to 800 mm, length ≤ 6000 mm | Machined valve and completion parts |
| Forged discs and blanks | Ø 100 to 2000 mm, thickness 30 to 600 mm | Closures, tube sheets, covers |
| Forged shafts and spindles | Ø 60 to 800 mm, length ≤ 8000 mm | Pump and compressor shafts, mandrels |
| Sleeves and bushings | OD ≤ 1500 mm, ID ≥ 60 mm | Wear sleeves, bearing housings |
| Hollow bars and forged tubes | OD ≤ 1200 mm, ID ≥ 60 mm | Heat exchanger and process components |
| Tube sheets | Ø ≤ 2500 mm | Shell and tube heat exchangers |
| Blocks and rectangular forgings | Length ≤ 3000 mm | Valve bodies, manifolds, blocks |
| Single-piece weight | 20 kg to 20 000 kg | All forms |
Supply conditions: as forged, rough machined, solution treated and aged, or finish machined to drawing. Send a drawing or the finished dimensions with your required specification and we will quote a forging weight and price.
§ 07
Applications and Industries
Alloy 725 is specified where a component has to carry high load in an environment that would attack a conventional high-strength steel. Typical uses of Alloy 725 forgings:
- Subsea and offshore oil production. Tubing hangers, hanger bodies, casing hangers, landing nipples, packers, mandrels, sour-service fasteners, wellhead and Christmas tree components.
- Valves and flow control. Forged valve bodies, valve stems, seat rings, blocks and closures for ball, gate, globe, check and plug valves.
- Pressure vessels and heat exchangers. Forged flanges, tube sheets, nozzles and shell sections for shell and tube exchangers, air receivers, columns and towers.
- Chemical and process plant. Pump shafts, plunger pump components, crystalliser parts and process module hardware in chloride-bearing or acidic service.
- Rotating and power transmission equipment. Shafts, spindles, gear blanks and compressor components where corrosion rules out alloy steel.
- Marine and shipbuilding. Forged rolls, wheels, manifolds and heavy machinery components in seawater service.
§ 08
Testing, Inspection and Certification
Every Alloy 725 forging leaving Jiangyin Jiangnan Metal Co., Ltd. ships with a material certificate to EN 10204 3.1. EN 10204 3.2 certification countersigned by a third-party inspection body such as SGS, BV, TUV, Lloyd's Register or DNV is available when the order calls for it.
| Test | Standard | Scope |
|---|---|---|
| Chemical analysis | ASTM E1473, spectrometric | Every heat |
| Tensile test | ASTM E8 / ISO 6892-1 | Every heat treatment lot |
| Hardness test | ASTM E18 (HRC) | Every heat treatment lot |
| Ultrasonic testing | ASTM A388, EN 10228-3, SEP 1921 | To specified acceptance class |
| Liquid penetrant testing | ASTM E165 / ISO 3452 | On request |
| Impact test | ASTM E23 / ISO 148-1 | On request |
| Grain size and microstructure | ASTM E112 | On request |
| Corrosion test | ASTM G48, NACE TM0177 | On request |
| Dimensional report | To customer drawing | Every piece |
Traceability runs from ingot to shipment. Heat number, forging lot, heat treatment charts and test locations are recorded and reported on the certificate. Hard stamping and paint marking follow the customer marking specification.
§ 09
Manufacturing Capability
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The plant sits in the Jiangyin forging cluster on the south bank of the Yangtze, about 150 km from the Port of Shanghai. Materials forged include carbon steel, alloy steel, tool steel, stainless steel and nickel-based superalloys such as Alloy 725, Inconel 718, Inconel 625, Incoloy 825, Monel 400 and the Hastelloy grades.
In-house capability covers open-die forging, seamless ring rolling, heat treatment with charted furnaces, ultrasonic and penetrant inspection, mechanical testing and rough machining. Forging, heat treatment and testing run under one roof, so Jiangyin Jiangnan Metal controls the route from ingot to certified forging and can hold delivery dates on prototype and repeat orders alike.
Enquiries are handled in English and Chinese. Send a drawing, a sketch with finished dimensions, or the alloy grade, product form and quantity, and the engineering team will confirm feasibility, forging weight and lead time.
§ 10
Request a Quotation for Alloy 725 Forgings
Send the drawing or finished dimensions of the Alloy 725 forging you need, together with the governing specification and quantity. We return a price and lead time, normally within one working day.
- Company Jiangyin Jiangnan Metal Co., Ltd.
- Factory No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Phone +86 189 2135 9659
- WhatsApp +86 189 2135 9659
- Email sales@steelforgepieces.com
- Website www.steelforgepieces.com
§ 11
Frequently Asked Questions About Alloy 725
Is Alloy 725 the same as Inconel 725?
Yes. Alloy 725 and Inconel 725 refer to the same material, UNS N07725. INCONEL is a registered trademark of Special Metals Corporation, so independent manufacturers describe the material by its generic designation, Alloy 725, or by its UNS number. Chemistry, heat treatment and mechanical requirements are identical.
What is the UNS number for Alloy 725?
The UNS number for Alloy 725 is N07725. It is also called Nickel Alloy 725 or NiCr21Mo9Nb. Supplier designations vary, so quote UNS N07725 on purchase orders to avoid ambiguity.
What is the difference between Alloy 725 and Alloy 625?
Alloy 725 and Alloy 625 share a similar nickel-chromium-molybdenum matrix, so their resistance to chloride pitting, crevice corrosion and stress-corrosion cracking is comparable. The difference is strength. Alloy 625 is solid-solution strengthened and supplied annealed at 414 MPa (60 ksi) minimum yield. Alloy 725 is age-hardenable and reaches 827 MPa (120 ksi) minimum yield after solution treatment and double ageing, roughly double the strength in the same corrosive service.
What is the difference between Alloy 725 and Alloy 718?
Both are gamma double-prime age-hardening alloys, but Alloy 718 contains only 2.8 to 3.3 percent molybdenum against 7.0 to 9.5 percent in Alloy 725. That extra molybdenum gives Alloy 725 better resistance to pitting and to sour, chloride-bearing environments. Alloy 718 is stronger, typically 1034 MPa minimum yield in the aerospace aged condition against 827 MPa for Alloy 725. Alloy 718 is chosen for maximum strength and Alloy 725 where corrosion resistance cannot be compromised.
What heat treatment is used for Alloy 725 forgings?
Alloy 725 forgings are solution treated at approximately 1038 °C (1900 °F), then double aged: held at about 732 °C (1350 °F) for 8 hours, furnace cooled at a controlled rate to about 621 °C (1150 °F), held a further 8 hours and air cooled. Jiangyin Jiangnan Metal Co., Ltd. runs solution treatment and both ageing steps as one controlled sequence and supplies the furnace charts with the certificate.
Is Alloy 725 suitable for sour service with H2S?
Alloy 725 is widely used for sour service and is listed in NACE MR0175 / ISO 15156-3 for wet H2S environments. Age-hardened Alloy 725 for oil and gas drilling and production equipment is covered by API 6ACRA. The permitted environmental envelope and hardness limits depend on material condition and the specific service, so confirm them against the current edition of the standard and your equipment specification before ordering.
Which standard covers Alloy 725 forgings?
Alloy 725 forgings are normally supplied to ASTM B564, the specification for nickel alloy forgings, with bar product to ASTM B805. Oilfield equipment usually invokes API 6ACRA and NACE MR0175 / ISO 15156-3 in addition. Jiangyin Jiangnan Metal Co., Ltd. manufactures Alloy 725 forgings to ASTM B564 and works to a customer specification where one is supplied.
Can Alloy 725 be welded?
Alloy 725 can be welded using processes and filler metals suitable for nickel-chromium-molybdenum-niobium alloys. Because strength comes from precipitation hardening rather than cold work, a welded assembly normally needs a full solution treatment followed by re-ageing to restore properties in the weld metal and heat-affected zone. Qualify the welding procedure with the design authority before production.
What is the largest Alloy 725 forging you can produce?
Jiangyin Jiangnan Metal Co., Ltd. produces Alloy 725 forgings from 20 kg to 20 000 kg per piece: seamless rolled rings to 2500 mm outside diameter, forged discs and tube sheets to 2500 mm diameter, round bars to 800 mm diameter and shafts to 8000 mm long. Send a drawing and we will confirm feasibility for anything outside this envelope.
What certification is supplied with Alloy 725 forgings?
Every order ships with a material certificate to EN 10204 3.1 covering chemical analysis, mechanical test results, heat treatment condition and heat number. EN 10204 3.2 certification countersigned by SGS, BV, TUV, Lloyd's Register or DNV is available on request, as are ultrasonic testing reports to ASTM A388, EN 10228-3 or SEP 1921.
What is the minimum order quantity and lead time for Alloy 725 forgings?
Jiangyin Jiangnan Metal Co., Ltd. accepts single-piece orders for Alloy 725 forgings, including prototypes and one-off replacement parts. Lead time depends on raw material availability, forging size and the heat treatment and testing scope. Contact sales@steelforgepieces.com with a drawing for a confirmed schedule.
§ 13
Reference Standards
- ASTM B564, Standard Specification for Nickel Alloy Forgings.
- ASTM B805, Standard Specification for Nickel-Chromium-Molybdenum-Niobium Alloy rod and bar.
- API 6ACRA, Age-Hardened Nickel-Based Alloys for Oil and Gas Drilling and Production Equipment.
- NACE MR0175 / ISO 15156-3, Materials for use in H2S-containing environments in oil and gas production.
- EN 10204, Metallic products, types of inspection documents.
Document JNM-DS-N07725
Title Alloy 725 (UNS N07725) Forgings, Material Data Sheet
Issued by Jiangyin Jiangnan Metal Co., Ltd., Jiangyin City, Jiangsu Province, China
Revision
Source https://www.steelforgepieces.com/Nickel-Alloy/ALLOY-725.html