Invar 36 Round Bars, Sheets and Plates: Sizes, Standards and Procurement Guide
Invar 36 is a nickel-iron low-expansion alloy used in precision engineering, aerospace tooling, instrumentation and specialised industrial applications. Its low coefficient of thermal expansion makes it suitable for components where dimensional stability across temperature changes is important.
Industrial buyers sourcing Invar 36 must consider more than the material grade. Product form, dimensions, material condition, applicable specifications, tolerances and test documentation all influence whether the supplied material meets the intended application requirements.
This guide explains the key considerations when purchasing Invar 36 round bars, sheets and plates.
What Is Invar 36?
Invar 36, also known as Alloy 36 or FeNi36, is a nickel-iron alloy containing approximately 36% nickel, with iron forming the balance.
Its defining characteristic is a low coefficient of thermal expansion over a specified temperature range. This property makes it useful for precision components that must minimise dimensional changes when temperatures fluctuate.
Common material designations include:
- Invar 36
- Alloy 36
- FeNi36
- UNS K93600
- W.Nr. 1.3912
These designations should be checked against the applicable material specification. Buyers should not assume that every designation or product standard is automatically interchangeable.
Invar 36 Round Bars
Invar 36 round bars are used in machined components, precision fixtures, tooling, instrumentation parts and specialised engineering assemblies.
Round bars can be processed through turning, milling, drilling and other machining operations to manufacture components with specific dimensions and tolerances.
Important Round Bar Buying Parameters
Before ordering Invar 36 round bars, confirm:
- Required diameter.
- Required length or cut-to-size dimensions.
- Dimensional tolerances.
- Material condition.
- Applicable specification.
- Surface finish requirements.
- Quantity and inspection requirements.
- Material test certificate requirements.
The required diameter and length should be clearly mentioned in the purchase enquiry. Availability and supply dimensions must be confirmed with the supplier rather than assumed from a general size chart.
Invar 36 Sheets and Plates
Invar 36 sheets and plates are used in precision tooling, dimensional control equipment, specialised fixtures, optical systems and other applications where low thermal expansion is important.
The choice between sheet and plate depends on thickness, component design, machining requirements and the applicable product specification.
Key Sheet and Plate Specifications
When sourcing Invar 36 sheets or plates, buyers should identify:
- Required thickness.
- Width and length.
- Flatness and dimensional tolerances.
- Supplied material condition.
- Surface condition.
- Required cutting or processing.
- Applicable material standard.
- Required inspection and documentation.
For precision applications, flatness and dimensional stability may be as important as nominal thickness. These requirements should be stated clearly in the purchase specification.
Invar 36 Sizes and Dimensional Requirements
There is no single universal size range that applies to every Invar 36 supplier or product specification.
Dimensions depend on the product form, manufacturing route, material condition and supplier’s supply capability.
A clear enquiry should specify the following:
| Product form | Information to provide |
|---|---|
| Round bars | Diameter, length, tolerance and quantity |
| Sheets | Thickness, width, length and quantity |
| Plates | Thickness, width, length, flatness and quantity |
| Cut pieces | Finished dimensions, tolerance and quantity |
For machined components, buyers should also account for machining allowance and final finished dimensions when determining the required raw material size.
Invar 36 Standards and Material Designations
Invar 36 is supplied against material specifications that define chemical composition, mechanical requirements, testing and product-form requirements.
Depending on the application, buyers may encounter designations such as UNS K93600 and W.Nr. 1.3912. The governing standard and its applicable edition should be confirmed before purchase.
ASTM International provides access to material standards and technical specifications. Buyers can consult ASTM International when identifying the relevant standard for their project.
A material designation alone may not define every requirement. The purchase order should clearly state the required product form, dimensions, condition and testing documentation.
Chemical Composition and Material Verification
Invar 36 is generally associated with approximately 36% nickel and iron as the balance. The permitted limits for nickel and other elements depend on the applicable specification.
For industrial procurement, buyers should verify the supplied material through its material test certificate rather than relying only on a commercial product description.
Important checks include:
- Grade and material designation.
- Chemical composition.
- Heat or batch identification.
- Mechanical test results where required.
- Material condition.
- Applicable specification.
- Traceability information.
For applications that depend on thermal expansion performance, buyers should separately specify the required coefficient of thermal expansion, temperature range and supporting test documentation.
Understanding Invar 36 Weight for Procurement
Weight estimation is useful when planning material requirements, transportation and purchasing quantities.
For a theoretical estimate of an Invar 36 round bar, the following formula can be used:
Weight (kg) = 0.00636 × D² × L
Where:
- D = diameter in millimetres.
- L = length in metres.
This estimate assumes a density of approximately 8.1 g/cm³. Actual weight can vary with the supplied material dimensions and density.
For sheets and plates, the theoretical weight can be estimated using:
Weight (kg) = Length × Width × Thickness × Density
For this calculation, use length, width and thickness in metres and density in kg/m³. An approximate density of 8,100 kg/m³ may be used for preliminary estimation, subject to confirmation against the material data.
These formulas are for planning purposes. Commercial invoicing weight should be confirmed using the supplier’s agreed weighing and measurement method.
Applications of Invar 36 Round Bars, Sheets and Plates
Different product forms support different manufacturing requirements.
Round Bar Applications
- Precision-machined components.
- Specialised engineering fixtures.
- Instrumentation components.
- Dimensional control assemblies.
- Custom tooling parts.
Sheet and Plate Applications
- Aerospace composite tooling.
- Precision moulds and fixtures.
- Optical and measurement equipment.
- Specialised instrument housings.
- Low-expansion engineering structures.
The final material selection should always be based on the operating temperature, dimensional tolerances, mechanical loading and applicable project requirements.
Invar 36 Procurement Checklist for Industrial Buyers
Before placing an order, use the following checklist to reduce specification gaps and procurement errors.
- Confirm the grade: Specify Invar 36 and the required material designation.
- Identify the product form: Round bar, sheet, plate or cut piece.
- Specify dimensions: Include diameter or thickness, width, length and tolerances.
- State the applicable standard: Mention the required specification and edition.
- Confirm material condition: State any required annealed or other specified condition.
- Define performance requirements: Include thermal expansion requirements where relevant.
- Request documentation: Specify MTC, chemical analysis and any additional testing.
- Confirm quantity: State the required number of pieces or total quantity.
- Clarify delivery requirements: Mention destination and required delivery schedule.
- Confirm commercial terms: Request pricing, taxes, packing and applicable delivery terms.
Sourcing Invar 36 from Manan Steel & Metals
Manan Steel & Metals, established in 2007, supplies specialty metals and industrial materials from Mumbai, India.
For buyers looking for Invar 36 round bars, sheets, plates and other material requirements, sharing complete technical details helps the team understand the required grade, product form and dimensions.
When requesting a quotation, provide:
- Invar 36 grade and designation.
- Required product form.
- Dimensions and tolerances.
- Quantity.
- Applicable specification.
- MTC and testing requirements.
- Delivery location.
Visit Manan Steel & Metals or submit your requirement through the official contact page.
Frequently Asked Questions About Invar 36 Sizes and Procurement
1. Is Invar 36 available in round bars?
Invar 36 is used in round bar form for precision-machined components and specialised engineering applications. Specific diameters, lengths and supply conditions should be confirmed with the supplier.
2. Can Invar 36 be supplied in sheets and plates?
Invar 36 is used in sheet and plate applications, including precision tooling and dimensional control equipment. Required thicknesses and dimensions must be checked against supplier capability and the applicable specification.
3. What is the density of Invar 36?
A commonly used approximate density for Invar 36 is 8.1 g/cm³. The actual value should be verified against the relevant material data for accurate engineering calculations.
4. What is the difference between Invar 36 and Alloy 36?
Invar 36 and Alloy 36 are commonly used names for the same low-expansion nickel-iron alloy family. Buyers should still confirm the exact grade designation and applicable specification before ordering.
5. Which documents should be requested when purchasing Invar 36?
Buyers should specify the applicable material test certificate and chemical composition report. Depending on the application, mechanical test results, thermal expansion data and traceability documents may also be required.
6. How can buyers calculate the weight of Invar 36 round bars?
A preliminary theoretical estimate can be calculated using:
Weight (kg) = 0.00636 × Diameter² (mm) × Length (m)
This uses an approximate density of 8.1 g/cm³. Actual supplied weight may differ.
Conclusion
Selecting the right Invar 36 round bar, sheet or plate requires attention to material designation, dimensions, tolerances, material condition and documentation. These details are particularly important in precision engineering and applications where low thermal expansion is a key design requirement.
Industrial buyers should provide complete technical specifications before ordering to ensure that the selected material matches the intended application.
For Invar 36 material enquiries, contact Manan Steel & Metals with your required product form, grade, dimensions and quantity.
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