Low-expansion alloy · Open-die forgings
1.3912 Forgings Invar 36 · Alloy 36 · FeNi36 · UNS K93600 · ASTM F1684
Forged rings, flanges, round bars, discs, shafts, sleeves, bushings and tube sheets in 1.3912 low-expansion alloy. Melting, forging, heat treatment, ultrasonic testing and certification are all carried out in our own plant.
Grade summary
1.3912 is the European material number (Werkstoff Nr.) for the binary iron-nickel low-expansion alloy containing 35 to 37 % nickel. It is sold commercially as Invar 36, Alloy 36, FeNi36 or Nilo 36, and is listed as UNS K93600 in the United States. The coefficient of thermal expansion is about 1.3 × 10-6 /K near room temperature, roughly one tenth that of 304 stainless steel. It stays low from cryogenic temperatures up to about 260 °C (500 °F).
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. We forge 1.3912 to customer drawings and supply it with EN 10204 3.1 or 3.2 material certificates.
- Ni 35.0-37.0 %
- CTE 1.3 x 10-6 /K
- EAF + VOD + ESR
- UT to EN 10228-3
- EN 10204 3.1 / 3.2
- Made to drawing
Thermal expansion
Why 1.3912 is specified
1.3912 is chosen when a part has to hold its dimensions through a temperature change. The chart compares it with three materials commonly considered for the same components.
Cross reference
1.3912 equivalent grades and standards
Drawings from different countries call this alloy by different names. The designations below all refer to the same nominal 36 % nickel-iron low-expansion alloy. If your drawing carries any of them, Jiangyin Jiangnan Metal can quote the forging.
| System / region | Designation | Notes |
|---|---|---|
| EN / DIN (Werkstoff Nr.) | 1.3912 | European material number |
| EN / DIN (name) | FeNi36 · NiFe36 | Chemical-symbol designation |
| UNS (USA) | K93600 · K93601 · K93603 | Varies with product form and purity |
| ASTM | F1684 Alloy 36 | Wrought low-expansion alloys |
| ASTM (sheet, strip, wire) | B388 · B753 | Applies to non-forged product forms |
| AFNOR (France) | NF A54-301 | Chemistry only |
| GB (China) | 4J36 | Chinese precision alloy designation |
| Trade names | Invar 36 · Nilo 36 · Pernifer 36 · Vacodil 36 | Trademarks of their owners, used here for identification only |
| Military | MIL-S-16598 · MIL-I-23011 Cl. 7 | Where invoked by the purchaser |
Equivalences are given for identification. The governing specification is the one named on the purchase order.
Datasheet
1.3912 chemical composition
Composition supplied by Jiangyin Jiangnan Metal for 1.3912 forgings, in weight percent. The melting route is EAF plus VOD followed by ESR remelting, which controls sulphur, gas content and inclusion cleanliness. These matter on a forging that will later be finish-machined to tight tolerance.
| Element | C | Si | Mn | P | S | Cr | Mo | Ni |
|---|---|---|---|---|---|---|---|---|
| wt. % | max 0.10 | max 0.50 | max 0.50 | max 0.025 | max 0.025 | max 0.50 | max 0.50 | 35.0-37.0 |
| Element | V | W | Ti | Cu | Al | Nb | Co | Fe |
|---|---|---|---|---|---|---|---|---|
| wt. % | n/s | n/s | n/s | n/s | n/s | n/s | max 1.00 | 60.00-65.00 |
n/s = not specified. Nickel is the controlling element and iron is the balance. Delivered chemistry is reported per heat on the EN 10204 certificate.
Datasheet
1.3912 mechanical properties
Tensile strength depends on delivery condition. Open-die forgings are normally supplied annealed. The harder tempers below apply to cold-worked bar and strip and are listed for reference when a drawing calls them out.
| Condition | Tensile strength, psi | Tensile strength, MPa |
|---|---|---|
| Annealed | 85,000 max | 586 max |
| 1/4 hard | 90,000 to 115,000 | 620 to 793 |
| 1/2 hard | 105,000 to 125,000 | 724 to 862 |
| Hard | 120,000 min | 827 min |
| Property | Metric | Imperial |
|---|---|---|
| Ultimate tensile strength | 490 MPa | 71 ksi |
| Yield strength, 0.2 % offset | 240 MPa | 35 ksi |
| Elongation in 50 mm | 42 % | 42 % |
Typical values for guidance, not guaranteed minima. Mechanical test results for your heat are reported on the material certificate. Section size, forging reduction and heat-treatment cycle all affect the result.
Datasheet
1.3912 physical properties
| Property | Value | Condition / note |
|---|---|---|
| Density | 8.1 g/cm3 (0.293 lb/in3) | Room temperature |
| Melting point | 1,429 °C (2,605 °F) | Approximate |
| Coefficient of thermal expansion | 1.3 x 10-6 /K | 20 to 100 °C, annealed |
| Low-expansion service range | cryogenic to 260 °C | Expansion rises above this range |
| Magnetic response | Ferromagnetic | At room temperature and throughout the low-expansion range |
| Annealing temperature | 830 to 900 °C | Slow cool. Cycle depends on section and stability requirement |
| Welding filler | CF36 bare wire | GTAW and GMAW |
Typical published values for the alloy class, given for design guidance. Confirm critical values against the applicable specification for your application.
Product forms
1.3912 forged product forms
All shapes are produced by open-die forging or ring rolling from ESR ingot, then heat treated and rough machined. Send a drawing or a finished-size sketch with your machining allowance and we quote from it.
-
Forged rings and seamless rolled rings
OD 200 to 3,000 mm
Height to 800 mm -
Forged flanges
WN, SO, BL, LJ, orifice
To ASME B16.5 / B16.47 or drawing -
Forged round bars
Dia 30 to 800 mm
Length to 6,000 mm -
Forged discs and disks
Dia 150 to 2,000 mm
Thickness 20 to 500 mm -
Forged shafts and spindles
Stepped, eccentric, hollow
Length to 6,000 mm -
Forged sleeves and bushings
OD 100 to 1,500 mm
Bored and rough machined -
Forged tube sheets
Dia to 3,000 mm
Drilled to layout on request -
Forged pipes and tubes
Bored from solid
Heavy wall, short length -
Valve components
Bodies, stems, seat rings, blocks
Ball, gate, globe, check, plug -
Custom open-die forgings
Blocks, nozzles, manifolds, rolls
Made entirely to drawing
Process route
How 1.3912 forgings are made
Every 1.3912 forging leaving Jiangyin Jiangnan Metal follows the same documented sequence. Each stage is recorded and traceable to the heat number printed on your certificate.
- Melting, EAF plus VODElectric arc furnace melting followed by vacuum oxygen decarburisation, which brings carbon, sulphur and dissolved gases down.
- Remelting, ESRElectroslag remelting refines the ingot structure, reduces segregation and improves inclusion cleanliness. This matters on a low-expansion alloy that has to stay dimensionally stable after machining.
- Open-die forging or ring rollingThe ingot is upset and drawn on the press, or pierced and rolled on the ring mill, to break down the cast structure and develop grain flow that follows the part contour.
- Heat treatmentAnnealing at 830 to 900 °C with slow cooling. Where maximum dimensional stability is specified, a stabilising cycle is added after rough machining.
- Rough machiningTurned or milled to the agreed allowance, so that ultrasonic testing sees a clean surface and the customer receives a part ready for finish machining.
- Non-destructive testingUltrasonic examination to EN 10228-3, SEP 1921 or ASTM A388 as specified. PT and hardness survey on request.
- Certification and releaseEN 10204 3.1 mill certificate as standard, or 3.2 with third-party witness. Marking, preservation and packing per your instructions.
Applications
Where 1.3912 forgings are used
The alloy is used where a part has to hold its dimensions through a temperature change.
Cryogenic and LNG
- Containment and membrane components for LNG tankers
- Transfer lines and pipe supports for liquefied gas
- Forged flanges and tube sheets for cryogenic heat exchangers
- Valve bodies and seat rings sealing from ambient down to -196 °C
Aerospace composite tooling
- Forged blocks and plates for composite lay-up moulds
- Mould frames that hold tolerance through the autoclave cycle
- Jigs and fixtures where CTE has to match the cured laminate
Precision instruments and optics
- Optical and laser bench structures
- Metrology frames, length standards, gauge bodies
- Positioning devices and stages for photonic equipment
- Seals, spacers and rigid instrument housings
Electronics and control
- Bimetal thermostat elements paired with a high-expansion alloy
- Cavity resonators for radar and microwave equipment
- Magnetic shielding and small transformer cores
- Clock balance wheels and pendulum rods, the original use for the alloy
Pressure equipment
- Forged flanges and tube sheets for shell-and-tube exchangers
- Nozzles and forged shells for air receivers and pressure vessels
- Heavy-wall bored forgings replacing seamless pipe in short lengths
Rotating and mechanical parts
- Shafts, spindles and eccentric shafts in precision drives
- Forged gears and rolls where centre distance has to stay fixed
- Bushings and sleeves running against dissimilar metals
Quality
Testing, inspection and certification
Non-destructive testing
- Ultrasonic testing to EN 10228-3, SEP 1921, ASTM A388, or the acceptance class named on your order
- Penetrant testing to ASTM E165 on machined surfaces where specified
- Dimensional inspection reported against the customer drawing before release
Documentation
- EN 10204 3.1. Mill certificate issued by our own quality department, supplied as standard
- EN 10204 3.2. Certificate countersigned by an independent inspection body such as SGS, BV, TÜV, Lloyd's or your nominated agency
- Reported data. Heat number, chemistry, mechanical results, heat-treatment record, NDT report
FAQ
1.3912 frequently asked questions
Answers to the questions that come up most often on enquiries for 1.3912 forgings.
What is 1.3912 material?
1.3912 is the European material number for a binary iron-nickel alloy containing 35 to 37 % nickel with iron as the balance. It is a low-expansion alloy, sold commercially as Invar 36, Alloy 36, Nilo 36 or FeNi36, and designated UNS K93600 in the United States. Its defining characteristic is a coefficient of thermal expansion near 1.3 x 10-6 /K around room temperature.
Is 1.3912 the same as Invar 36?
Yes. 1.3912 and Invar 36 describe the same alloy. 1.3912 is the European material number and Invar 36 is a trade name. Alloy 36, Nilo 36, Pernifer 36, FeNi36, 4J36 and UNS K93600 all refer to the same nominal composition. Minor limits on residual elements can differ between the governing standards, so the specification named on the purchase order still controls acceptance.
What is the chemical composition of 1.3912?
Nickel 35.0 to 37.0 %, iron 60.00 to 65.00 %, carbon max 0.10 %, silicon max 0.50 %, manganese max 0.50 %, phosphorus max 0.025 %, sulphur max 0.025 %, chromium max 0.50 %, molybdenum max 0.50 % and cobalt max 1.00 %. Jiangyin Jiangnan Metal reports the actual heat chemistry on the EN 10204 certificate supplied with every forging.
What is the thermal expansion coefficient of 1.3912?
About 1.3 x 10-6 per kelvin between 20 and 100 °C in the annealed condition, roughly one tenth that of 304 stainless steel. The coefficient stays low from cryogenic temperatures up to about 260 °C (500 °F), then rises steadily above that. Exact values depend on heat treatment and prior cold work, so parts requiring maximum dimensional stability receive a stabilising cycle after rough machining.
Can 1.3912 be forged, and what forged shapes are available?
Yes. 1.3912 forges readily using practices similar to austenitic stainless steel. Jiangyin Jiangnan Metal produces 1.3912 as open-die forged rings, seamless rolled rings, flanges, round bars, discs, shafts, spindles, sleeves, bushings, tube sheets, bored pipes and tubes, valve bodies, seat rings, blocks and nozzles, all made to customer drawings.
Is 1.3912 magnetic?
Yes. 1.3912 is ferromagnetic at room temperature and throughout the temperature range where it shows its low-expansion behaviour. If your application requires a non-magnetic low-expansion material, this alloy will not be suitable and a different grade should be selected.
Is 1.3912 weldable?
Yes. 1.3912 is welded by GTAW and GMAW using CF36 bare filler wire. Surfaces must be free of oil, oxide and marking materials before welding. Where dimensional stability is critical, a post-weld stress-relief cycle is normally applied before finish machining.
How does 1.3912 resist corrosion?
1.3912 resists corrosion adequately in dry air at room temperature but will rust in moist air, because it is an iron-nickel alloy with no deliberate chromium addition. Parts held in storage or shipped by sea should be oiled or otherwise preserved. Painting or plating is common where the alloy will be exposed in service.
What certificates come with 1.3912 forgings?
EN 10204 3.1 mill certificates are supplied as standard, covering heat number, chemical analysis, mechanical test results, heat-treatment record and NDT report. EN 10204 3.2 certificates witnessed by SGS, BV, TÜV, Lloyd's or your own nominated inspector are available on request. Ultrasonic testing is performed to EN 10228-3, SEP 1921 or ASTM A388 as specified on the order.
Who supplies 1.3912 open-die forgings?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory located at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. It manufactures 1.3912 (Invar 36) forgings to customer drawings and ships worldwide. Enquiries: +86 189 2135 9659 or sales@steelforgepieces.com.
How do I get a price for a 1.3912 forging?
Send a drawing or a dimensioned sketch to sales@steelforgepieces.com. Include the shape, finished or rough-machined size, quantity, delivery condition and any testing or certification requirements. A quotation normally follows within one working day. If you only have a finished-part drawing, we will propose the forging envelope and machining allowance ourselves.
Manufacturer
Jiangyin Jiangnan Metal Co., Ltd.
We are an open-die forging factory in Jiangyin, Jiangsu Province, about one hour from the Port of Shanghai. We forge nickel alloys, stainless steel, tool steel, alloy steel and carbon steel to customer drawings, and ship finished, certified parts to pressure equipment, valve, aerospace, cryogenic and instrument manufacturers worldwide.
- CompanyJiangyin Jiangnan Metal Co., Ltd.
- AddressNo. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone+86 189 2135 9659
- Emailsales@steelforgepieces.com
- Websitewww.steelforgepieces.com
- CapabilityOpen-die forging, ring rolling, heat treatment, machining, NDT
Document reference
- Document
- 1.3912 (Invar 36) forging datasheet
- Issued by
- Jiangyin Jiangnan Metal Co., Ltd., No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Contact
- +86 189 2135 9659, sales@steelforgepieces.com
- Page
- https://www.steelforgepieces.com/Nickel-Alloy/1.3912.html
- Revision date