1.3927 Forgings: Alloy 48 (UNS K94800) Rings, Flanges, Shafts and Bars
1.3927 is the Werkstoff number for Alloy 48, a nickel iron alloy with about 48% nickel and the rest iron. The same material is listed as UNS K94800, ASTM F30, DIN 17745 and AFNOR NF A54-301. Werkstoff numbers 1.3922 and 1.3926 cover it too. Mills and stockists also sell it as NILO 48, Pernifer 48, Invar 48, Glass Seal 48 and SUPRA 50. Its expansion rate follows soft lead and soda lime glass closely, which is why it goes into glass to metal seals and into industrial thermostats running up to 450 °C (840 °F).
Jiangyin Jiangnan Metal Co., Ltd. forges 1.3927 into rings, seamless rolled rings, flanges, shafts, discs, sleeves, bushings, tube sheets and round bars. We are an open die forging works at Zhouzhuang Town, Jiangyin, Jiangsu, China. Every piece leaves with an EN 10204 3.1 certificate, or 3.2 if you ask for it at order stage.
- Werkstoff
- 1.3927
- UNS
- K94800
- ASTM
- F30
- Nickel
- 48% nom.
- Density
- 8.20 g/cm³
- Inflection pt.
- 460 °C
1.3927 equivalent grades and specifications
Enquiries for this alloy arrive under a dozen different names. Quote any designation in the table and you get the same material.
| System | Designation | Notes |
|---|---|---|
| Werkstoff (W.-Nr.) | 1.3927 | 1.3922 and 1.3926 cover the same alloy |
| DIN | DIN 17745 | Wrought nickel iron alloys, controlled expansion |
| UNS | K94800 | Unified Numbering System |
| ASTM | ASTM F30 | Sheet, strip, rod, bar, tubing and wire |
| AFNOR | NF A54-301 | French standard |
| AWS | AWS 092 | Welding designation |
| Trade and shop names | Alloy 48, NILO 48, Pernifer 48, Invar 48, Glass Seal 48, SUPRA 50 | Also written Ni-Fe 48, NiFe48, Ni48 |
Do not confuse this with Invar 36. Invar 36 (W.-Nr. 1.3912, UNS K93600) has almost no expansion and is bought for dimensional stability. Alloy 48 expands more, on purpose, to follow glass. If your drawing wants stability rather than a glass seal, go to our Invar 36 forgings page.
Chemical composition of 1.3927
We melt 1.3927 by EAF plus VOD or by ESR. Both routes keep sulphur, phosphorus and gas content down. Inclusions and segregation ruin the expansion behaviour and leak a glass to metal seal, so there is no point saving money at the melt shop.
| Element | Minimum % | Maximum % | Nominal % |
|---|---|---|---|
| Nickel (Ni) | - | - | 48.0 |
| Cobalt (Co) | - | 1.00 | - |
| Manganese (Mn) | - | 0.80 | - |
| Silicon (Si) | - | 0.30 | - |
| Chromium (Cr) | - | 0.25 | - |
| Aluminium (Al) | - | 0.10 | - |
| Carbon (C) | - | 0.05 | - |
| Sulphur (S) | - | 0.025 | - |
| Phosphorus (P) | - | 0.025 | - |
| Iron (Fe) | Balance | ||
Nickel is trimmed inside its range to hit the expansion figure on the order, so a mill certificate for 1.3927 will read close to 48.0% but rarely exactly 48.0%. That is how the alloy is controlled and it is not a deviation.
Mechanical and physical properties
The figures below are typical for annealed material, which is the condition 1.3927 forgings normally ship in. Cold work left in the part shifts the expansion curve, so anything going into a seal or a thermostat should not be delivered work hardened.
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength | 520 MPa | 75 ksi |
| Yield strength (0.2% offset) | 260 MPa | 38 ksi |
| Elongation in 50 mm | 43% | 43% in 2 in |
| Hardness, annealed | 80 HRB max | 80 HRB max |
| Density | 8.20 g/cm³ | 0.296 lb/in³ |
| Inflection point | 460 °C | 860 °F |
| Mean expansion coefficient, 20 to 400 °C | 9 to 10 x 10⁻⁶ /K | 5.0 to 5.6 x 10⁻⁶ /°F |
| Max. thermostat service temperature | 450 °C | 840 °F |
Treat these as design guidance, not acceptance criteria. For a glass seal the expansion curve is the property that decides whether the job works, and it has to be agreed against the governing specification before we start. Tell us the glass you are sealing to and we will fix the expansion requirement with the mill.
1.3927 forged products we make
We are a forging works, not a trading house. The billet is upset, drawn, punched and ring rolled on our own presses at Zhouzhuang Town. The forms below are ones we run regularly in 1.3927.
| Form | Size range | Typical use |
|---|---|---|
| Seamless rolled rings | OD 200 to 2,500 mm, height up to 600 mm | Sealing rings, resonator bodies, shielding rings |
| Forged rings and flanges | OD 100 to 2,000 mm | Vacuum device flanges, lamp and tube seal flanges |
| Round bars | dia. 20 to 600 mm | Thermostat rods, machined seal blanks |
| Discs and blocks | dia. 100 to 1,500 mm | Positioning devices, bimetal components |
| Shafts and spindles | dia. 50 to 800 mm, length up to 6,000 mm | Instrument shafts, eccentric shafts |
| Sleeves and bushings | OD 80 to 1,200 mm | Glass to metal seal housings, spacers |
| Tube sheets | dia. up to 2,500 mm | Heat exchanger tube sheets in controlled expansion duty |
| Forged pipes and tubes | OD 100 to 1,200 mm | Transfer lines, cryogenic and LNG components |
Parts go out as forged, rough machined or finish machined to your drawing. If you want us to leave stock on, tell us how much per side, otherwise we work to normal open die allowance. We also run forged rolls, forged tube sheets and forged valve seat rings in this and other nickel alloys.
Melting, forging and testing
Process route
EAF plus VOD or ESR melt, then ingot or billet, soak at roughly 1150 °C, open die forge or ring roll with the finish above about 900 °C, anneal, machine off the allowance, test, then final inspection and marking.
Non destructive testing
Every 1.3927 forging is ultrasonically tested. We work to EN 10228-3, SEP 1921 or ASTM A388, to the quality class stated on the order. Dye penetrant, magnetic particle inspection, hardness survey, mechanical testing and dimensional reports are available if you need them.
Certificates
EN 10204 3.1 mill certificate as standard. EN 10204 3.2 with a third party witness, TUV, SGS, BV, Lloyds Register or your own inspector, when it is stated at order stage. Each piece is hard stamped with its heat number so it can be traced back to the certificate.
Where 1.3927 is used
| Sector | Components | Why this alloy |
|---|---|---|
| Glass to metal sealing | Seal rings, sleeves, bushings and flanges for lamp bulbs, radio valves and vacuum devices | Expansion follows soft lead and soda lime glass, so the seal stays tight through thermal cycling |
| Industrial controls | Thermostat rods, bimetal strip parts, temperature regulators, relay parts | Predictable expansion up to 450 °C |
| Microelectronics | Semiconductor lead frames, electronic housings, hermetic packages | Controlled expansion plus soft magnetic behaviour |
| RF and microwave | Cavity resonators, echo boxes and filters for mobile telephony, magnetic shielding | Frequency holds steady as temperature moves |
| Precision instruments | Metrology devices, clock balance wheels, pendulum rods, optical frames | Dimensions repeat |
| Cryogenic and LNG | Transfer line parts, containers and fittings for LNG duty | Low temperature toughness with controlled contraction |
| Valves | Valve stems, seat rings, bodies and blocks for ball, gate, globe, check and plug valves | Used where sealing faces have to hold clearance across a temperature range |
Machining, welding and heat treatment
Machining. 1.3927 cuts much like an austenitic stainless. It is gummy and work hardens, so use sharp positive rake tooling, a rigid setup, plenty of coolant, low speed and a heavy feed. Do not let the tool dwell in the cut.
Hot and cold working. Same processes as austenitic stainless. Put in an interstage anneal after heavy cold reduction.
Heat treatment. The alloy does not age harden. Annealing and stress relief are used to even out the structure, hold dimensions and put the expansion curve back after working. Parts going to a glass seal usually get a final anneal in a controlled atmosphere so a clean, adherent oxide can be grown before sealing.
Welding. Matching filler or a compatible nickel filler. Weld metal and heat affected zone can expand differently from the parent metal, so on sealing components agree the weld positions at design stage rather than after the part is made.
Common questions about 1.3927
What is material 1.3927?
1.3927 is the Werkstoff number for Alloy 48, a nickel iron alloy with about 48% nickel and the rest iron. Its expansion rate follows soft lead and soda lime glass, so it is used for glass to metal seals and for industrial thermostats up to 450 °C. It sits under DIN 17745 and matches UNS K94800 and ASTM F30.
What is 1.3927 equivalent to?
UNS K94800, ASTM F30, DIN 17745 and AFNOR NF A54-301. Werkstoff numbers 1.3922 and 1.3926 cover the same alloy. Trade and shop names include Alloy 48, NILO 48, Pernifer 48, Invar 48, Glass Seal 48, SUPRA 50, AWS 092 and NiFe48.
What is the chemical composition of 1.3927?
Nickel 48.0% nominal, iron balance. Maximum limits are cobalt 1.00, manganese 0.80, silicon 0.30, chromium 0.25, aluminium 0.10, carbon 0.05, sulphur 0.025 and phosphorus 0.025%. Full table is in chemical composition above.
Can 1.3927 be forged, and at what temperature?
Yes. It open die forges and ring rolls without trouble. Normal practice is to soak at about 1150 °C and finish above roughly 900 °C, then anneal. Cold work left in the part shifts the expansion curve, so parts for sealing or thermostat duty go out annealed. We agree the exact route against your specification before cutting the billet.
What is the difference between 1.3927 and Invar 36?
Invar 36 (1.3912, UNS K93600) runs about 36% nickel and has almost no expansion, which is why it goes into tooling, gauges and cryogenic work. Alloy 48 runs about 48% nickel and expands at roughly 9 to 10 x 10⁻⁶ per K, set to follow soda lime glass. The two are not interchangeable.
Is 1.3927 magnetic?
Yes. It is ferromagnetic at room temperature and also serves as a soft magnetic material for shielding, small transformer cores and relay parts. The magnetic transition, quoted as the inflection point, sits near 460 °C. Above it the low expansion behaviour is gone.
What testing and certificates come with the forgings?
Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, whichever the order calls for, plus an EN 10204 3.1 mill certificate as standard. EN 10204 3.2 with a third party witness (TUV, SGS, BV, Lloyds Register or your own inspector) if it is stated at order stage. Each piece is hard stamped with its heat number.
How do I get a quotation?
Send the drawing or the finished sizes, the quantity, the specification and any testing or certificate requirement to sales@steelforgepieces.com, or call +86-189-2135-9659. Quotes normally go back within 24 hours.
Request a quotation for 1.3927 forgings
Send us the following and we will normally come back inside 24 hours:
- Drawing or finished sizes, and how much machining stock to leave
- Quantity and the date you need it
- Specification: 1.3927, Alloy 48, UNS K94800 or ASTM F30
- Testing and certificate level, EN 10204 3.1 or 3.2, and the UT class
- The glass type, if the part is a glass to metal seal