--- title: "NCF 625 Forgings, JIS G4902 Alloy 625 Forged Rings, Flanges, Bars and Shafts" description: "NCF 625 (JIS G4902 / UNS N06625 / Alloy 625) open-die forgings: rolled rings, flanges, bars, shafts, discs. EN 10204 3.1/3.2 certified. Jiangyin, China." canonical: "https://www.steelforgepieces.com/Nickel-Alloy/NCF625.html" manufacturer: "Jiangyin Jiangnan Metal Co., Ltd." address: "No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China" telephone: "+86-189-2135-9659" email: "sales@steelforgepieces.com" grade: "NCF 625" equivalents: "UNS N06625, Alloy 625, Inconel 625, W.Nr. 2.4856, NiCr22Mo9Nb, NC22DNb, NA 21, NW6625, NS3306" standards: "JIS G4902, ASTM B564, ASME SB-564, ASTM B443, ASTM B446" updated: "2026-08-22" --- # NCF 625 Forgings, Made to Drawing NCF 625 is the JIS G4902 designation for the nickel-chromium-molybdenum-niobium alloy also written as UNS N06625, Alloy 625, Inconel 625 and W.Nr. 2.4856. Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu, China. We forge NCF 625 into seamless rolled rings, flanges, bars, shafts, discs, sleeves and tube sheets, solution annealed, ultrasonically tested, and certified to EN 10204 3.1 or 3.2. | | | |---|---| | Nickel | 58% min | | Chromium | 20-23% | | Molybdenum | 8-10% | | Nb + Ta | 3.15-4.15% | | Density | 8.44 g/cm3 | | Service temperature | -196 to 980 C | ## What NCF 625 is, and why it is forged NCF 625 is a solid-solution-strengthened nickel alloy. Molybdenum and niobium dissolved in the nickel-chromium matrix carry the strength rather than a hardening heat treatment, so the alloy holds its properties from cryogenic temperature up to about 980 C. The same chemistry makes it resistant to chloride stress-corrosion cracking, pitting and crevice attack in seawater, sour gas, and both oxidising and reducing acids. Open-die forging closes the porosity left by casting, refines grain size, and aligns grain flow with the principal stress direction of the part. A forged NCF 625 flange or ring is denser and tougher than the same shape cut from plate or bar stock, and it gives cleaner ultrasonic results. Jiangyin Jiangnan Metal Co., Ltd. produces NCF 625 as custom open-die forgings and seamless rolled rings. We work to drawing rather than from a stock catalogue, and there is no tooling charge for standard open-die shapes. Send a drawing or the finished dimensions and we forge to that print. ## NCF 625 equivalent grades and standards Drawings from different countries call this alloy by different names. All of the designations below cover the same UNS N06625 chemistry. | Standard or region | Designation | Product form covered | |---|---|---| | JIS (Japan) | NCF 625 | G4902 plate and sheet; G4901 bar; G4903 pipe; G4904 tube | | UNS (USA) | N06625 | All forms | | ASTM / ASME | B564 / SB-564 | Nickel alloy forgings, the usual specification for forged parts | | ASTM | B446 | Bar and rod | | ASTM | B443 | Plate, sheet and strip | | Werkstoff (Germany) | 2.4856 | All forms | | DIN / EN name | NiCr22Mo9Nb | All forms | | AFNOR (France) | NC22DNb | All forms | | BS (UK) | NA 21 | All forms | | ISO | NW6625 | All forms | | GB (China) | NS3306 / GH3625 | All forms | | Trade names | Inconel 625, Nicrofer 6020 hMo, Chronin 625, Haynes 625, Altemp 625 | All forms | | Sour service | NACE MR0175 / ISO 15156-3 | Compliant material available on request | Inconel is a registered trademark of Special Metals Corporation. Nicrofer is a registered trademark of VDM Metals. Haynes is a registered trademark of Haynes International. These names are listed for cross-reference only. Jiangyin Jiangnan Metal is not affiliated with or endorsed by those companies. ## NCF 625 chemical composition Weight percent, to JIS G4902, identical to UNS N06625. | Element | Min | Max | Role in the alloy | |---|---|---|---| | Ni (nickel) | 58.0 | - | Austenitic matrix, SCC resistance | | Cr (chromium) | 20.0 | 23.0 | Oxidation and pitting resistance | | Mo (molybdenum) | 8.0 | 10.0 | Crevice and reducing-acid resistance | | Nb + Ta (niobium, tantalum) | 3.15 | 4.15 | Solid-solution strengthening, carbide stabilisation | | Fe (iron) | - | 5.0 | Residual | | C (carbon) | - | 0.10 | Restricted to limit carbide precipitation | | Si (silicon) | - | 0.50 | Residual from deoxidation | | Mn (manganese) | - | 0.50 | Residual | | Al (aluminium) | - | 0.40 | Deoxidiser | | Ti (titanium) | - | 0.40 | Deoxidiser, carbide and nitride former | | Co (cobalt) | - | 1.0 | Residual, restricted for nuclear service | | P (phosphorus) | - | 0.015 | Impurity | | S (sulphur) | - | 0.015 | Impurity, controlled for hot workability | Actual heat analysis is reported per heat number on the EN 10204 certificate. Tighter internal limits can be agreed at order, for example cobalt 0.10% max for nuclear service, or restricted niobium for weld-overlay compatibility. ## Mechanical and physical properties ### Room-temperature mechanical minima | Condition | 0.2% proof stress | Tensile strength | Elongation | Hardness | |---|---|---|---|---| | Solution annealed (Grade 2, 1090 C min) | 275 N/mm2 min | 690 N/mm2 min | 30% min | typ. 75-95 HRB | | Annealed (Grade 1, 870-1040 C) | 379 N/mm2 min | 758 N/mm2 min | 30% min | 35 HRC max | Grade 1 is the normal choice for service below about 600 C and for NACE MR0175 sour-service applications, where the 35 HRC cap applies. Grade 2 is specified where creep strength above 600 C governs. State the grade on the enquiry. If it is not stated, parts are supplied solution annealed. ### Physical properties | Property | Value | |---|---| | Density | 8.44 g/cm3 (0.305 lb/in3) | | Melting range | 1290-1350 C | | Modulus of elasticity | 207.5 GPa | | Thermal conductivity | 9.8 W/m.K | | Mean coefficient of thermal expansion, 20-100 C | 12.8 um/m.K | | Specific heat capacity | 410 J/kg.K | | Electrical resistivity | 1.29 uOhm.m | | Magnetic permeability at 20 C | 1.0006, non-magnetic | | Curie temperature | below -196 C | ### Corrosion and temperature performance - Chloride stress-corrosion cracking: effectively immune, which is why NCF 625 replaces austenitic stainless steel in seawater and sour-gas duty. - Pitting and crevice corrosion: PREN above 45, giving resistance in warm chloride environments where 316L and duplex grades fail. - Oxidising acids: good performance in nitric and mixed acids from the 20-23% chromium. - Reducing acids: good performance in sulphuric, phosphoric and hydrochloric service from the 8-10% molybdenum. - Oxidation: scaling resistance to approximately 980 C in air. - Cryogenic service: retains toughness and ductility down to -196 C, so the alloy is used in LNG hardware. - Sensitisation range: prolonged exposure between roughly 650 C and 900 C precipitates carbides and gamma double prime phase and lowers ductility. Allow for this in design and in post-weld heat treatment. ## NCF 625 forged product range All shapes below are produced in NCF 625 as open-die forgings or seamless rolled rings, made to drawing. Contact us with the finished dimensions to confirm the size range for a specific part. - Seamless rolled rings. Rolled, not cut from plate. Circumferential grain flow. - Forged rings and hollow blanks. Trepanned or mandrel-forged, any wall to bore ratio. - Forged flanges. WN, SO, blind, orifice, long WN, to ASME B16.5, B16.47 or custom. - Forged round bars. Peeled or rough-turned, cut to length. - Shafts and spindles. Stepped, hollow-bored, eccentric. - Discs and blanks. OD greater than length, upset-forged for radial grain flow. - Sleeves, bushings and cylinders. Bored and honed on request. - Tube sheets. Solid or clad, drilled to layout on request. - Valve bodies, seat rings and stems for ball, gate, globe, check and plug valves. NACE MR0175 available. - Nozzles, manifolds and blocks. Wellhead and Christmas tree parts. - Pipe and tube blanks. Forged and bored hollows. - Custom shapes to print. No tooling cost for standard open-die work. ## How an NCF 625 forging is made Each stage below generates a record that appears on the material certificate. 1. **Melting and remelting.** EAF with AOD or VOD refining, followed by electroslag remelting to control segregation and inclusion content. VIM plus ESR or VIM plus VAR is available for aerospace and critical service. 2. **Ingot inspection and cropping.** Heat analysis confirmed by spectrometer before the ingot is released. Hot top and bottom cropped. 3. **Heating and open-die forging.** Soaked and forged between 1150 C and 1200 C, finishing above 950 C. Reduction ratio and upsetting sequence are set so that grain flow follows the loaded direction of the part. 4. **Ring rolling.** Ring geometries are pierced and then rolled to a seamless ring. Grain flow runs circumferentially, which a ring cut from plate cannot reproduce. 5. **Heat treatment.** Annealed at 870-1040 C for Grade 1, or solution annealed at 1090-1200 C for Grade 2, then rapid cooled. Charts and furnace records are retained per heat-treatment lot. 6. **Rough or finish machining.** Turned, bored, faced or drilled to the agreed condition: as-forged, rough machined with allowance, or fully finished to print. 7. **Non-destructive testing.** Ultrasonic testing after heat treatment and rough machining, plus liquid penetrant testing and positive material identification. NCF 625 is non-magnetic, so PT replaces magnetic particle inspection. 8. **Certification and marking.** Hard-stamped or vibro-etched with heat number and part number, then released against an EN 10204 3.1 or 3.2 certificate. ## Inspection, testing and certification Supplied with every NCF 625 forging: - Chemical analysis reported by heat number - Tensile, yield and elongation at 20 C - Hardness, HRB or HRC to specification - Impact testing, Charpy V, on request - Heat-treatment charts and furnace records - UT to ASTM A388, SEP 1921 or EN 10228-3 - PT to ASTM E165 or EN ISO 3452 - PMI by portable XRF or OES - Grain size to ASTM E112 - Intergranular corrosion test, ASTM G28 method A - NACE MR0175 / ISO 15156-3 compliance statement - Dimensional report against your drawing - EN 10204 3.1 mill certificate as standard - EN 10204 3.2 witnessed by BV, SGS, TUV, LR or DNV - Heat-to-part traceability, hard stamped - Third-party or customer source inspection welcome ## Where NCF 625 forgings are used | Industry | Typical NCF 625 forged components | Reason for the alloy | |---|---|---| | Offshore and subsea oil and gas | Wellhead and Christmas tree bodies, hubs, connectors, hangers, forged blocks | Sour service, seawater, chloride SCC immunity | | Valves | Bodies, bonnets, seat rings, stems, balls, gates, plugs | Erosion and corrosion resistance, NACE compliance | | Chemical and petrochemical | Reactor nozzles, flanges, tube sheets, agitator shafts, pump parts | Mixed oxidising and reducing acid duty | | Pressure vessels and heat exchangers | Tube sheets, shell flanges, nozzles, forged heads, air receivers | ASME code service at elevated temperature | | Flue-gas desulphurisation | Scrubber internals, forged rings, dampers | Wet acid chloride condensate | | Power generation | Turbine seal rings, gas compressor parts, fasteners, gearbox rings | Creep and oxidation strength above 600 C | | Marine and shipbuilding | Propulsion shafts, sleeves, seawater pump bodies | Seawater and crevice corrosion | | Pulp, paper and bleaching | Digester hardware, rolls, forged discs | Chlorine dioxide and organic acids | | Pharmaceutical and biochemical | Crystalliser parts, agitator shafts, sanitary flanges | Cleanability and product purity | | Aerospace and nuclear | Bellows blanks, ducting rings, structural forgings | Cryogenic to high-temperature strength, low cobalt on request | ## Frequently asked questions ### What is NCF 625? NCF 625 is the Japanese Industrial Standard designation for a nickel-chromium-molybdenum-niobium alloy containing at least 58% nickel, 20-23% chromium, 8-10% molybdenum and 3.15-4.15% niobium plus tantalum. It is specified in JIS G4902 and is the same material as UNS N06625, Alloy 625 and W.Nr. 2.4856. NCF 625 combines high strength with resistance to pitting, crevice corrosion, chloride stress-corrosion cracking and oxidation, from cryogenic temperature up to about 980 C. ### Is NCF 625 the same as Inconel 625? Yes. NCF 625 and Inconel 625 describe the same alloy chemistry, UNS N06625. NCF 625 is the JIS designation used in Japan, Inconel 625 is a registered trade name of Special Metals Corporation, and 2.4856 is the German Werkstoff number. Jiangyin Jiangnan Metal Co., Ltd. supplies forgings in this alloy against whichever designation and standard your drawing calls out. ### What is the chemical composition of NCF 625? Per JIS G4902: carbon 0.10% max, silicon 0.50% max, manganese 0.50% max, phosphorus 0.015% max, sulphur 0.015% max, nickel 58.0% min, chromium 20.0-23.0%, molybdenum 8.0-10.0%, niobium plus tantalum 3.15-4.15%, iron 5.0% max, aluminium 0.40% max, titanium 0.40% max and cobalt 1.0% max. This composition is identical to UNS N06625 in ASTM B443, B446 and B564. ### What are the mechanical properties of NCF 625 forgings? Solution annealed as Grade 2, NCF 625 forgings meet a minimum tensile strength of 690 N/mm2, a minimum 0.2% proof stress of 275 N/mm2 and a minimum elongation of 30%. Annealed as Grade 1, the minima are 758 N/mm2 tensile, 379 N/mm2 proof stress and 30% elongation. Grade 1 is used up to about 600 C. Grade 2 is specified where creep resistance above 600 C is required. ### Which forged shapes can be produced in NCF 625? Jiangyin Jiangnan Metal produces NCF 625 in open-die and ring-rolled form: seamless rolled rings, forged flanges, round bars, shafts, spindles, discs, blanks, sleeves, bushings, hollow cylinders, tube sheets, nozzles, valve bodies, valve seat rings, valve stems, blocks and custom shapes made to drawing. There is no tooling charge for standard open-die shapes. ### How is NCF 625 melted and heat treated? NCF 625 is melted by electric arc furnace with AOD or VOD refining followed by electroslag remelting. VIM plus ESR or VIM plus VAR is available for aerospace and critical service. Alloy 625 is solid-solution strengthened, so it is supplied annealed at 870-1040 C or solution annealed at 1090-1200 C and rapid cooled. Ageing is not standard practice for corrosion service because it lowers ductility and corrosion resistance. ### What testing and certification is supplied with NCF 625 forgings? Every forging ships with a chemical analysis by heat, mechanical test results, heat-treatment records and traceable heat and part numbers. Ultrasonic testing is carried out to ASTM A388, SEP 1921 or EN 10228-3 acceptance classes by agreement, with liquid penetrant testing to ASTM E165 and positive material identification. Certification is issued to EN 10204 3.1, or EN 10204 3.2 with third-party witness by BV, SGS, TUV, Lloyd's Register or DNV. ### What industries use NCF 625 forgings? Offshore and subsea oil and gas production, wellhead and Christmas tree components, valves and valve internals, chemical and petrochemical process plant, pressure vessels and shell-and-tube heat exchangers, flue-gas desulphurisation, seawater and marine equipment, power generation and turbine hardware, pulp and paper, pharmaceutical and biochemical plant, and nuclear and aerospace components. ### Where is your NCF 625 forging factory located? Jiangyin Jiangnan Metal Co., Ltd. operates an open-die forging plant at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Jiangyin is on the Yangtze River in the Suzhou, Wuxi and Changzhou industrial belt, about 30 km from Zhangjiagang Port and 150 km from the Port of Shanghai. Enquiries: +86-189-2135-9659 or sales@steelforgepieces.com. ### How do I request a quotation for NCF 625 forgings? Send a drawing or the finished dimensions to sales@steelforgepieces.com with the quantity, the specification you need (NCF 625, UNS N06625, Alloy 625 or 2.4856), the delivery condition of as-forged, rough machined or finish machined, the required test scope and the certification level. Jiangyin Jiangnan Metal returns a price and lead time, normally within one working day. ## About the manufacturer Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China. The plant forges custom parts and seamless rolled rings in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys, including NCF 625, Inconel 625, NCF 690, Alloy 600 (2.4816) and Alloy 718 (2.4668), and supplies them to buyers in the oil and gas, valve, chemical process, power generation, marine and heavy machinery sectors worldwide. All work is made to drawing. Parts are released against EN 10204 3.1 or 3.2 certification with heat-to-part traceability, and customer or third-party source inspection is accepted at any stage of production. | | | |---|---| | Company | Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory | | Plant address | No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China | | Telephone, WhatsApp, WeChat | +86-189-2135-9659 | | Email | sales@steelforgepieces.com | | Website | https://www.steelforgepieces.com/ | | Nearest ports | Zhangjiagang, about 30 km; Shanghai, about 150 km | ## Related grades Nickel alloys: [Inconel 625](https://www.steelforgepieces.com/Nickel-Alloy/inconel-625.html), [NCF 690](https://www.steelforgepieces.com/Nickel-Alloy/NCF690.html), [2.4668 Alloy 718](https://www.steelforgepieces.com/Nickel-Alloy/2.4668.html), [2.4816 Alloy 600](https://www.steelforgepieces.com/Nickel-Alloy/2.4816.html), [all nickel alloy forgings](https://www.steelforgepieces.com/Nickel-Alloy/). Precipitation-hardening stainless: [PH13-8Mo](https://www.steelforgepieces.com/Stainless-Steel/PH13-8Mo.html), [17-4PH](https://www.steelforgepieces.com/Stainless-Steel/17-4ph.html), [15-5PH](https://www.steelforgepieces.com/Stainless-Steel/15-5ph.html), [17-7PH](https://www.steelforgepieces.com/Stainless-Steel/17-7ph.html). --- Technical data on this page is compiled from JIS G4902 and ASTM B443, B446 and B564 and is given for guidance. It is not a warranty of properties for any specific application. Confirm requirements against your own specification before ordering. Inconel is a registered trademark of Special Metals Corporation and is used here for cross-reference only. Copyright 2026 Jiangyin Jiangnan Metal Co., Ltd. Page last reviewed 22 August 2026.