4J36 (Invar 36, UNS K93600) is a 36% nickel low-expansion iron-nickel alloy with a mean coefficient of thermal expansion of about 1.2×10⁻⁶/°C from −80 to +100 °C — roughly one tenth that of ordinary steel. It is used where dimensional stability is critical: precision instruments, LNG tanks and composite tooling.
As a manufacturer and global exporter of special alloys since 2012, Shanghai Hangbo Alloy Group Co., Ltd. supplies Invar 36 / 4J36 as round bars (φ2–600 mm, up to 12 m), plates & sheets (0.5–100 mm thick, up to 2500 mm wide), precision strip (0.02–3.0 mm, ±0.005 mm tolerance), seamless tubes & pipes (φ6–630 mm OD, 0.5–40 mm wall), forgings & rolled rings (up to 7500 kg, 3500 mm OD) — all with EN 10204 3.1 certified material test reports.
Invar 36 / 4J36 Chemical Composition (wt%)
| Element | Content (wt%) | Element | Content (wt%) |
|---|---|---|---|
| Fe (铁) | Balance | Si (硅) | ≤ 0.30 |
| Ni (镍) | 35.0–37.0 | C (碳) | ≤ 0.05 |
| Co (钴) | ≤ 0.50 | P (磷) | ≤ 0.020 |
| Mn (锰) | 0.20–0.60 | S (硫) | ≤ 0.020 |
Invar 36 / 4J36 Mechanical Properties
| Property | Value |
|---|---|
| Tensile strength (Rm) | ≥ 440 MPa |
| Yield strength (Rp0.2) | ≥ 240 MPa |
| Elongation (A) | ≥ 30 % |
| Hardness | ≤ 170 HB |
| Density | 8.10 g/cm³ |
| Melting range | 1430–1450 °C |
| Thermal conductivity | 10.5 W/m·K |
| Young's modulus | 141 GPa |
| Max service temperature | −80 ~ +100 ℃ (dimensional stability range) |
Key Advantages
- CTE near room temperature of about 1.2×10⁻⁶/°C
- Outstanding dimensional stability for precision reference parts
- Most stable between −80 and +100 °C
- Retains good toughness at cryogenic temperatures (LNG)
Relevant Standards
- ASTM F1684
- GB/T 14985
- UNS K93600
Typical Applications
- LNG carrier tanks and transfer piping
- Precision instruments, clocks and measurement standards
- Aerospace composite lay-up tooling
- Electronic packaging and lead frames
- Liquefied gas tank liners
Why Buy from Hangbo Alloy?
- Factory-direct manufacturer — founded 2012, headquartered in Shanghai Qingpu
- Full product range — bar, plate, sheet, strip, tube, forging, welding wire, flanges and machined parts
- Certified quality — ISO 9001:2015, GB/T 19001-2016, GJB 9001C-2017, EN 10204 3.1 mill test certificates with third-party inspection (SGS / BV / TUV) available on request
- Complete mill documentation — chemical analysis, mechanical test, ultrasonic test (UT), hardness and grain-size reports with every shipment
Contact Us — Shanghai Hangbo Alloy Group Co., Ltd.
Shanghai Hangbo Alloy Group Co., Ltd.
📍 No. 388 Songhuang Road, Qingpu District, Shanghai, China
📞 Tel / WhatsApp: +86 15618279078
✉️ Email: demi@nickel-alloy.com
🕒 Available 24 hours a day, 7 days a week — enquiries answered around the clock.
Send your drawing or enquiry (grade, form, size, quantity, standard) for a same-day quotation.
Frequently asked questions
Why is Invar 36's expansion so low?
This is the Invar effect: the 36% nickel iron-nickel alloy exhibits volume magnetostriction below its Curie temperature, so the normal lattice expansion with temperature is offset by magnetic contraction, giving very low net thermal expansion. Above the Curie point (about 230 °C) the CTE rises rapidly to that of ordinary steel.
What forms and sizes are available?
We supply Invar 36 / 4J36 as round bars (φ2–600 mm, up to 12 m), plates & sheets (0.5–100 mm thick, up to 2500 mm wide), precision strip (0.02–3.0 mm, ±0.005 mm tolerance), seamless tubes & pipes (φ6–630 mm OD, 0.5–40 mm wall), forgings & rolled rings (up to 7500 kg, 3500 mm OD). Custom lengths, tolerances and machining to drawing are available on request.
What is the MOQ and lead time?
MOQ is flexible — trial orders from a single piece are welcome. Stock sizes ship in 3–7 days; custom forgings and machined parts typically 15–35 days depending on quantity and process.
Can you provide third-party inspection and shipping to my port?
Yes. SGS / BV / TUV or your nominated inspector can witness all tests before shipment. Full export documentation is provided, and we ship worldwide by sea or air on FOB, CIF or DDP terms.