Alloy 36 (Invar): Complete Properties & Application Guide

← Back to Knowledge Center

Overview

Alloy 36, also known as Invar (UNS K93600 / W.Nr. 1.3912), is a nickel-iron alloy with an extremely low coefficient of thermal expansion, approximately one-tenth that of carbon steel at room temperature. This unique property makes it invaluable for precision instruments and dimensional-stability-critical applications.

Chemical Composition

The chemical composition of Alloy 36 (Invar) is carefully controlled to achieve its unique combination of properties and performance characteristics.

Element	Min %	Max %
Iron (Fe)	Balance	Balance
Nickel (Ni)	35.0	37.0
Carbon (C)	—	0.05
Manganese (Mn)	—	0.35
Silicon (Si)	—	0.35
Chromium (Cr)	—	0.25
Cobalt (Co)	—	0.50

Mechanical Properties at Room Temperature

The mechanical properties of Alloy 36 (Invar) vary depending on product form and heat treatment condition. The data below represents typical values for solution-annealed material.

Property	Value
Tensile Strength	517 MPa
Yield Strength (0.2% offset)	276 MPa
Elongation in 2 inches	35%
Density	8.05 g/cm3
Melting Point	1430 °C
Max Service Temperature	260 °C

Corrosion Resistance

Good atmospheric corrosion resistance. Not recommended for corrosive environments without protective coating. The alloy can be plated or coated to enhance corrosion resistance for specific applications.

Applications

The unique combination of properties makes Alloy 36 (Invar) suitable for a wide range of demanding applications:

• Precision Instruments: Seismographs, chronometers, and surveying equipment.
• LNG Industry: Membrane containment systems for LNG carriers and storage tanks.
• Electronics: Lead frames, shadow masks, and electronic components.
• Aerospace: Composite tooling and mold materials.
• Cryogenics: Pipelines and vessels for cryogenic fluid transport.

Available Product Forms

Hangbo Alloy Group manufactures and supplies Alloy 36 (Invar) in the following product forms, conforming to ASTM, AMS, and ASME specifications:

• Round Bars: Diameters from 6 mm to 300 mm, hot-finished or cold-drawn, solution annealed.
• Seamless Tubes & Pipes: Sizes from 6 mm OD to 219 mm OD, various wall thicknesses.
• Plates & Sheets: Thicknesses from 0.5 mm to 50 mm, hot-rolled or cold-rolled.
• Forgings: Custom flanges, rings, discs, and complex shapes per customer drawing.
• Welding Wire: Diameters 0.8 mm to 5.0 mm, precision-wound coils and spools.

Related Standards

Standard	Description
ASTM F1684	Low Expansion Alloy
ASTM B753	Thermostat Metals
AMS I-23011	Military Specification
DIN 1715	German Standard
GB/T 4339	Chinese Standard
JIS H2501	Japanese Standard

Contact Us for Alloy 36 (Invar)

Hangbo Alloy Group maintains extensive inventory of Alloy 36 (Invar) in all standard product forms. We can provide mill test certificates, third-party inspection reports (SGS, TUV), and custom processing services.

For quotations, material certifications, or technical consultation, contact our sales team or call +86-136-1165-6360. We typically respond within 10 minutes.