When a precision instrument manufacturer faced challenges with dimensional instability due to thermal expansion, the solution was found in Invar Round Bars. Known for their extremely low coefficient of thermal expansion, these bars enable precise and stable components across aerospace, chemical, marine, power, and pharmaceutical industries. Engineers and procurement teams rely on Aurico Alloys LLP’s Invar bars to ensure product accuracy, reduced downtime, and improved safety.
Table of Contents:
Invar 36 (UNS K93603, ASTM F1684, Werkstoff 1.3912) is a nickel-iron alloy with approximately 36% nickel content, which minimizes thermal expansion to near zero over a wide temperature range. This unique property makes it indispensable in applications requiring dimensional stability such as aerospace instrument components, satellite platforms, optical devices, and precision machinery.
Aurico Alloys LLP offers Invar round bars from 6mm to 200mm diameter, with finishes including bright, polished, rough turned, and ground. Supplied with mill test certificates and full batch traceability conforming to ASTM, EN, DIN, ISO, and NACE MR0175 standards, these bars support high-specification manufacturing and critical project compliance worldwide.
Invar bars stand apart due to their low thermal expansion, excellent corrosion resistance, good machinability, and weldability ideal for chemical process plant components, precision instruments, cryogenic equipment, and marine applications where stability and reliability are paramount.
High-quality Invar Round Bars ready for industrial use.
Specification Overview
| Supplier & Manufacturer | Aurico Alloys LLP |
|---|---|
| Grade | Invar 36 |
| Standards | One rod and bar specification, in the identity table below. VDM also lists DIN 17745 and SEW 385 for this form. Inspection certificates to EN 10204. |
| Diameter Range | 6mm – 200mm |
| Length | 100mm – 6000mm |
| Finish | Bright, polished, rough turned, ground, no. 4 finish |
| Delivery | Full MTC, batch traceability, export packaging |
Equivalent Grades & Standards
| Property | Value |
|---|---|
| UNS number | K93600 / K93601 / K93602 / K93603 |
| Werkstoff / EN number | 1.3912 |
| EN designation | Ni36 |
| Density | 8.1 g/cm3 |
| Melting range | 1430 °C |
| Specific heat capacity (20 °C) | 486 J/kg·K |
| Thermal conductivity (20 °C) | 12.8 W/m·K |
| Electrical resistivity (20 °C) | 78 µΩ·cm |
| Modulus of elasticity (20 °C) | 143 GPa |
| Curie temperature | 230 °C |
| Rod and bar specification | ASTM F1684 |
Identifiers and physical constants for Invar 36. A dash means no such designation is published for this grade.
Stock & Product Availability
Aurico Alloys LLP stocks Invar round bars in various diameters and finishes, ready for global dispatch for precision and industrial applications requiring certified traceability and documentation.
Chemical Composition
| Element | Min (%) | Max (%) |
|---|---|---|
| Nickel (Ni) | 35 | 37 |
| Chromium (Cr) | — | 0.25 |
| Iron (Fe) | — | Balance |
| Cobalt (Co) | — | 0.5 |
| Manganese (Mn) | — | 0.6 |
| Silicon (Si) | — | 0.4 |
| Carbon (C) | — | 0.05 |
| Sulfur (S) | — | 0.015 |
| Phosphorus (P) | — | 0.015 |
Composition limits for Invar 36. These are specification limits for the grade, not measured values for a lot; the mill test certificate supplied with your order states the actual analysis.
Mechanical & Physical Properties
| Property | Typical Value |
|---|---|
| Tensile Strength (MPa) | 552 |
| Yield Strength (MPa) | 260 |
| Elongation (%) | 35 |
| Coefficient of Thermal Expansion (10^-6 /°C) | 1.2 (20-100°C) |
Applications & Benefits
- Precision instruments and optical devices requiring dimensional stability
- Cryogenic and aerospace instruments and structural components
- Chemical process plant components needing low thermal expansion
- Marine applications requiring corrosion and thermal shock resistance
- Electrical and magnetic shielding in electronic devices
- Industrial tooling and precision manufacturing equipment
FAQ & Search Trends
Global Export Destinations
We ship worldwide from Mumbai. See every destination we export to on our export markets page.
Domestic Supply Network Across India
We deliver across India from our Mumbai stockyard. See every city we supply on our supply locations page.
Conclusion
Invar Round Bars from Aurico Alloys LLP combine dimensional precision, corrosion resistance, and certified quality to serve chemical, marine, aerospace, power, and precision instrument industries globally. Are your precision-critical assets secured with the unparalleled stability of Invar?