Nickel Alloy · Grade Reference & Supply
Alloy 475 Forgings: Rings, Flanges, Bars, Discs and Shafts
Alloy 475 is a designation shared by two unrelated materials. NILO® Alloy 475 (Werkstoff 2.4486) is a nickel-iron controlled-expansion alloy with 46–48 % nickel, used for glass-to-metal seals. Custom 475 is a premium-melted martensitic precipitation-hardening stainless steel that reaches up to 2000 MPa (290 ksi) tensile strength. Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China, forges both variants into rings, flanges, bars, discs and shafts, supplied with EN 10204 3.1 or 3.2 certification.
- Grade
- Alloy 475
- Also known as
- NILO 475 · Custom 475
- Werkstoff (var. A)
- 2.4486
- Standards (var. A)
- DIN 17745 · NF A54-301
- Product forms
- Rings · Flanges · Bars · Discs
- Process
- Open-die forged / ring rolled
- NDT
- EN 10228-3 · SEP 1921 · A388
- Certificate
- EN 10204 3.1 / 3.2
- Forged by
- Jiangyin Jiangnan Metal
- Plant
- Zhouzhuang, Jiangyin, CN
- Melting route
- EAF + VOD · ESR opt.
- Lead time
- 25–35 days
Which Alloy 475 do you need?
Check the variant before ordering. Two materials are sold under the number 475 and they are not interchangeable. The controlled-expansion grade is austenitic and is specified for its low thermal expansion. The stainless grade is martensitic and is specified for strength. Ordering the wrong one is the most common cause of a rejected Alloy 475 delivery, so Jiangyin Jiangnan Metal checks the variant against your drawing before a heat is released.
Variant A Controlled expansion
NILO® Alloy 475
A nickel-iron alloy with 46–48 % nickel, balance iron. Its thermal expansion coefficient of roughly 9–10 × 10⁻⁶/°C sits close enough to soft lead and soda-lime glass to form a hermetic seal.
- Werkstoff 2.4486 · DIN 17745 · NF A54-301
- Austenitic, non-magnetic above the Curie point
- Not age hardenable; strength comes from working and grain control
- Related grades: Alloy 42, 45, 46, 48, 52, Invar 36
Variant B High strength
Custom 475 stainless
A premium-melted martensitic precipitation-hardening stainless steel, roughly 11 Cr, 8 Ni, 5 Mo, 8.5 Co and 1.25 Al, balance iron. Tensile strength reaches 2000 MPa (290 ksi) with usable toughness and resistance to atmospheric corrosion.
- Proprietary CarTech® grade; ordered to datasheet or customer spec
- Martensitic and magnetic
- Age hardenable, H975 peak age at 525 °C (975 °F)
- Related grades: Custom 455, Custom 465, 13-8Mo, 17-4PH
If your drawing calls out a glass sealing application, a Curie temperature or an expansion coefficient, you need Variant A. If it calls out an ageing condition such as H975 or H1000, or a tensile strength above 1400 MPa, you need Variant B.
Chemical composition of Alloy 475
Variant A: NILO® Alloy 475 (2.4486)
| Element | Symbol | Content, wt % |
|---|---|---|
| Nickel | Ni | 46.0 – 48.0 |
| Iron | Fe | Balance |
| Manganese | Mn | 0.30 – 0.60 |
| Silicon | Si | 0.15 – 0.30 |
| Carbon | C | 0.05 max |
| Cobalt | Co | 0.50 max |
| Copper | Cu | 0.10 max |
| Chromium | Cr | 0.10 max |
| Aluminium | Al | 0.10 max |
| Sulfur | S | 0.015 max |
| Phosphorus | P | 0.015 max |
Chromium-bearing sealing variants (for example the 47Ni–6Cr type used where the oxide layer must bond directly to the glass) are a different specification. State the chromium requirement on your enquiry if your seal depends on it.
Variant B: Custom 475 stainless
| Element | Symbol | Content, wt % |
|---|---|---|
| Chromium | Cr | 10.50 – 11.50 |
| Nickel | Ni | 7.50 – 8.50 |
| Cobalt | Co | 8.00 – 9.00 |
| Molybdenum | Mo | 4.50 – 5.50 |
| Aluminium | Al | 1.00 – 1.50 |
| Manganese | Mn | 0.50 max |
| Silicon | Si | 0.50 max |
| Carbon | C | 0.015 max |
| Phosphorus | P | 0.015 max |
| Sulfur | S | 0.010 max |
| Iron | Fe | Balance |
Figures above are nominal specification ranges for grade selection. The certified heat analysis for your order is issued on the EN 10204 3.1 or 3.2 certificate that ships with the forgings.
Physical and mechanical properties
Variant A: NILO® Alloy 475, typical values
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.20 g/cm³ | 0.296 lb/in³ |
| Melting range | ≈ 1425 °C | ≈ 2597 °F |
| Mean thermal expansion, 20–400 °C | 9.0 – 10.0 × 10⁻⁶/°C | 5.0 – 5.6 × 10⁻⁶/°F |
| Curie temperature | 350 – 370 °C | 662 – 698 °F |
| Thermal conductivity at 20 °C | 13.5 W/m·K | 7.8 Btu/hr·ft·°F |
| Electrical resistivity | 0.48 µΩ·m | 289 Ω·cmil/ft |
| Modulus of elasticity | 145 GPa | 21.0 × 10⁶ psi |
| Specific heat | 505 J/kg·K | 0.121 Btu/lb·°F |
| Tensile strength, annealed | 500 – 600 MPa | 73 – 87 ksi |
Variant B: Custom 475 stainless, typical values
| Condition | Tensile strength | Notes |
|---|---|---|
| H975, peak aged at 525 °C (975 °F) | up to 2000 MPa / 290 ksi | Maximum strength with usable toughness and ductility |
| Aged 525–595 °C (975–1100 °F) | Lower, tunable | Higher ageing temperature trades strength for toughness |
| Solution treated | Soft martensite | Condition for machining and forming before ageing |
Section size affects achievable properties in heavy forgings. Confirm the test location and orientation required by your specification (surface, mid-radius, or ½ T) at enquiry stage.
Alloy 475 forged product range and sizes
Jiangyin Jiangnan Metal Co., Ltd. open-die forges Alloy 475 to drawing. The table below gives the working envelope at the Zhouzhuang plant. Send a drawing and the achievable forged size and machining allowance will be confirmed against it.
| Forged form | Size range | Typical use |
|---|---|---|
| Forged rings / seamless rolled rings | 200 – 3000 mm OD | Sealing rings, housings, bearing races, flange blanks |
| Forged flanges | 100 – 2000 mm OD | Vacuum and pressure joints, instrument connections |
| Round bars | 80 – 1200 mm dia. | Machining stock, shafts, valve stems, pins |
| Discs and blanks | up to 2500 mm dia. | Tube sheets, closure plates, gear and rotor blanks |
| Shafts and spindles | up to 6000 mm long | Drive shafts, eccentric shafts, rolls, spindles |
| Sleeves and bushings | 100 – 1500 mm OD | Wear sleeves, spacers, guide bushings |
| Hollow forgings and tube sections | to drawing | Pipe sections, cylinders, pressure housings |
| Valve components | to drawing | Bodies, stems, seat rings, blocks, nozzles |
Single piece weight 20 kg to 20,000 kg. Supplied as-forged, rough machined, heat treated, or finish machined to print.
How Alloy 475 forgings are produced
The route from melted heat to certified forging at the Zhouzhuang plant.
- Melting
EAF plus VOD refining. ESR remelt is added when the drawing calls for premium-melted material.
- Ingot inspection and cropping
Ladle analysis verified, then hot-top and bottom ends cropped to remove segregation and shrinkage.
- Open-die forging
Upsetting and drawing under hydraulic press to break down the cast structure, targeting a reduction ratio of at least 4:1 in the finished section.
- Ring rolling
For seamless rolled rings, the pierced blank is expanded on a radial-axial ring mill to finished diameter and wall.
- Heat treatment
Variant A is annealed to set grain size and expansion behaviour. Variant B is solution treated then aged, for example H975 at 525 °C.
- Rough machining
Scale and decarburised skin removed, opening a clean surface for ultrasonic inspection.
- Testing
Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, plus chemistry, mechanical, hardness and dimensional inspection.
- Certification and despatch
EN 10204 3.1 mill certificate, or EN 10204 3.2 countersigned by a third-party inspection body where required.
Applications for Alloy 475 forgings
Variant A: controlled-expansion applications
- Glass-to-metal seals in soft lead and soda-lime glasses: hermetic feedthroughs, headers, eyelets
- Lamp and vacuum devices: lead-in wires, envelope components, electron tube parts
- Microelectronic packages: sealing frames, lids, hermetic housings
- Thermostatic bimetal: the low-expansion side of the strip
- Optical and laser systems: mounts, spacers, frames and supports that hold alignment through temperature change
- Precision instruments: metrology fixtures, clock and balance components, positioning devices
- Composite tooling: moulds whose expansion has to track a carbon-fibre layup
- RF and microwave hardware: cavity resonators, filters, magnetic shielding, electronic housings
Variant B: high-strength applications
- Aerospace fittings: structural attachments, actuator parts, high-load pins
- Valve internals: stems, seat rings, blocks and bodies under high pressure
- Rotating parts: shafts, spindles and eccentric shafts needing strength with corrosion resistance
- Offshore and downhole tooling: components exposed to marine atmospheres
- High-strength fasteners and load-bearing hardware
Testing, inspection and certification
| Check | Method / standard | Supplied as |
|---|---|---|
| Chemical analysis | Spectrometry, heat and product analysis | Certificate, per heat |
| Ultrasonic testing | EN 10228-3 · SEP 1921 · ASTM A388 | UT report with acceptance class |
| Mechanical testing | Tensile, yield, elongation, reduction of area | Certificate, per lot |
| Impact testing | Charpy V-notch at specified temperature | On request |
| Hardness | Brinell or Rockwell, mapped where specified | Certificate |
| Grain size / microstructure | Metallographic examination | On request |
| Dimensional inspection | Against approved drawing | Inspection report |
| Documentation | EN 10204 3.1 or 3.2 | 3.2 countersigned by SGS, BV or TÜV |
Third-party inspection can be witnessed at the plant. Nominate your inspection body on the purchase order so hold points are built into the routing.
Alloy 475 frequently asked questions
What is Alloy 475?
Alloy 475 is a designation shared by two unrelated materials. NILO® Alloy 475 (Werkstoff 2.4486, DIN 17745) is a nickel-iron controlled-expansion alloy with 46–48 % nickel, used for glass-to-metal seals in soft lead and soda-lime glass. Custom 475 is a premium-melted martensitic precipitation-hardening stainless steel containing roughly 11 % chromium, 8 % nickel, 5 % molybdenum, 8.5 % cobalt and 1.25 % aluminium, used where tensile strength up to 2000 MPa is needed with good corrosion resistance. Jiangyin Jiangnan Metal Co., Ltd. open-die forges both.
Are there really two different materials called Alloy 475?
Yes. They share a trade number and nothing else. NILO Alloy 475 is austenitic, cannot be age hardened, and is chosen for a thermal expansion coefficient of about 9–10 × 10⁻⁶/°C that matches soft glass. Custom 475 is martensitic, is age hardenable, and is chosen for strength. Confusing them is the single most common cause of a rejected Alloy 475 order, so Jiangyin Jiangnan Metal asks every buyer to confirm the intended grade against the drawing before the heat is released.
What is the chemical composition of Alloy 475?
NILO Alloy 475 is nominally 46.0–48.0 % nickel with the balance iron, plus 0.30–0.60 % manganese, 0.15–0.30 % silicon, 0.05 % carbon maximum and low residual cobalt, copper, chromium and aluminium. Custom 475 is nominally 10.50–11.50 % chromium, 7.50–8.50 % nickel, 4.50–5.50 % molybdenum, 8.00–9.00 % cobalt, 1.00–1.50 % aluminium, 0.015 % carbon maximum, 0.50 % manganese maximum and 0.50 % silicon maximum, balance iron. Certified heat analysis is supplied on the EN 10204 3.1 or 3.2 certificate.
What is Alloy 475 used for?
NILO Alloy 475 is used for glass-to-metal seals in soft lead and soda-lime glass, lamp and vacuum device components, thermostatic bimetal, optical and laser instrument frames, magnetic shielding and precision metrology parts. Custom 475 is used for high-strength shafts, valve stems and seats, fasteners, aerospace structural fittings and downhole tooling where both strength and corrosion resistance are required.
Which standards cover Alloy 475?
NILO Alloy 475 is covered by DIN 17745 as Werkstoff 2.4486 and by AFNOR NF A54-301. Custom 475 is a proprietary CarTech® grade, normally purchased to the producer's datasheet or to a customer aerospace specification. Jiangyin Jiangnan Metal supplies forgings to either route and ultrasonically tests to EN 10228-3, SEP 1921 or ASTM A388.
What forged shapes can be made from Alloy 475?
Jiangyin Jiangnan Metal open-die forges Alloy 475 as forged rings and seamless rolled rings, flanges, round bars, discs, shafts, spindles, eccentric shafts, sleeves, bushings, tube sheets, tubes and pipe sections, valve bodies, valve stems and seat rings, nozzles, manifolds, gear blanks, rolls, and custom blanks made to drawing.
What sizes of Alloy 475 forgings can be supplied?
Rings are produced from 200 mm to 3000 mm outside diameter, round bars from 80 mm to 1200 mm diameter, and discs to 2500 mm diameter, with single piece weights from 20 kg to 20,000 kg. Send the drawing or the finished dimensions and Jiangyin Jiangnan Metal will confirm the achievable forged size and machining allowance.
What testing and certification is supplied?
Every lot is supplied with chemical analysis, mechanical properties, hardness and dimensional inspection. Ultrasonic testing is performed to EN 10228-3, SEP 1921 or ASTM A388 as specified. Documentation is issued as an EN 10204 3.1 mill certificate, or an EN 10204 3.2 certificate countersigned by a third-party inspection body such as SGS, BV or TÜV on request.
How does Alloy 475 differ from Alloy 42, 46, 48 and 52?
All are nickel-iron controlled-expansion alloys in the same family, and the number tracks nickel content, which sets the thermal expansion coefficient. Alloy 42 has about 42 % nickel and the lowest expansion of the group, Alloy 46 about 46 %, NILO Alloy 475 about 47 %, Alloy 48 about 48 % and Alloy 52 about 51 %. The grade is selected to match the expansion of the specific glass or ceramic being sealed, so Alloy 52 suits soft soda-lime glass while Alloy 42 suits harder sealing glasses.
What is the minimum order quantity and lead time?
Jiangyin Jiangnan Metal accepts single-piece orders for Alloy 475 forgings, including one-off prototypes and replacement parts. Typical lead time is 25 to 35 days from drawing approval, depending on section size, heat treatment and whether third-party inspection is required.
How do I get a quote for Alloy 475 forgings?
Email the drawing or the required dimensions to sales@steelforgepieces.com, or call +86 189 2135 9659. Include the grade variant, forged or finish-machined condition, quantity, applicable specification and any NDT or certification requirement. Jiangyin Jiangnan Metal replies to Alloy 475 enquiries within 24 hours on working days.
Request a quotation for Alloy 475 forgings
Send a drawing or the finished dimensions. Quotations for Alloy 475 forgings are returned within 24 hours on working days.
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
- Plant
- No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu, China
- Telephone
- +86 189 2135 9659
Jiangyin Jiangnan Metal Co., Ltd. (2026). Alloy 475 Forgings: Rings, Flanges, Bars and Discs. Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/Alloy-475.html