4J36 (Invar 36) is a nickel-iron low expansion alloy featuring an extremely low coefficient of thermal expansion near room temperature. It maintains dimensional stability across -60°C to 100°C, with a linear expansion coefficient as low as 1.2×10⁻⁶/°C. The alloy exhibits good ductility, toughness, and machinability, and remains ferromagnetic below its Curie point of 230°C. Widely used in precision instruments, aerospace components, optical systems, and cryogenic equipment where dimensional stabi

Advantage

1.Ultra-low thermal expansion (≈1.2×10⁻⁶/°C), near-zero dimensional change from -60°C to 100°C 2.Excellent dimensional stability and high precision for critical components 3.Good ductility, weldability, and machinability for complex part fabrication 4.Consistent mechanical properties and low magnetic permeability at cryogenic temperatures

Ingredient

• Ni
• 35.0 ~ 37.0
• Fe
• Balance
• Mn
• 0.20 ~ 0.60
• Si
• ≤0.30
• C
• ≤0.05
• P
• ≤0.020
• S
• ≤0.020
• Co
• ≤0.50

Standard

• USA
• ASTM F1684 / ASME SF1684
• China
• GB/T 15018‑2017、YB/T 5241‑2021

Mechanics

• STATE
• RP
• YIELD
• EXTEND
• SHRINK
• HARDNESS
• IMPACT
• Annealed
• ≥450 MPa
• ≥240 MPa
• ≥30 %
• ≥40 %
• ≤160 HBW
• ≥27 J

• STATE
• Annealed
• RP
• ≥450 MPa
• YIELD
• ≥240 MPa
• EXTEND
• ≥30 %
• SHRINK
• ≥40 %
• HARDNESS
• ≤160 HBW
• IMPACT
• ≥27 J