Subscribe to our Newsletter
Model No: Elinvar Alloy
Elinvar Alloy - ASTM E112 - AMS 5668
Elinvar's constant elasticity is achieved through carbide precipitation, making it suitable for the mass production of watch hairsprings, precision springs, bellows, and shaped spring strips.
Quantity :
Product Introduction
If you have previously purchased spring steel, stainless steel, or even Ni-Span C, you might assume that Elinvar is merely another alloy with"decent elastic properties."
However, Elinvar addresses a fundamentally different pain point.
However, Elinvar addresses a fundamentally different pain point.
Unlike Ni-Span C—which relies on the γ' precipitate phase (Ni₃Ti/Al) to achieve constant elasticity—Elinvar takes a different approach: carbide strengthening (specifically, the M₇C₃ type). It represents an"industrially friendly"version of a constant-elasticity alloy; its compositional tolerance is an order of magnitude greater than that of Ni-Span C, and its thermal stability is significantly superior.
So, who needs Elinvar?
- Are you gearing up for mass production rather than simply fabricating a few laboratory prototypes?
- Is your supplier's heat-treatment furnace control limited to ±20°C, making it impossible to demand a tighter tolerance of ±5°C?
- Do you require a material with a virtually constant elastic modulus across a wide temperature range—from -40°C to +80°C—yet find that your budget cannot accommodate the cost of Ni-Span C?
Elinvar is the robust, practical choice. While it may not boast the absolute highest performance specifications, it is arguably the most suitable constant-modulus alloy for industrial-scale manufacturing.
*The Elinvar alloy supplied by Lork Group is delivered in strict compliance with AMS 5668 and ASTM E112 standards, accompanied by a comprehensive Certified Material Test Report (CMTR). If you are engaged in the mass production of precision instruments, watch hairsprings, or mechanical filters, read on.
Chemical Composition
(Compliant with AMS 5668 / ASTM Specifications)
| Material Type | C | W | Si | Ni | Cr | Mn | Fe |
|---|---|---|---|---|---|---|---|
| Content (%) | 0.2 - 2.0 | 1 - 3 | 0.3 - 2.0 | 33 - 35 | 5 - 12 | 0.45 - 2.4 | Balance |
Lork's Advice: When you receive a material certificate, focus on three key elements: Ni, C, and W. Any deviation in these three components will directly impact the final constant-elasticity performance.
Mechanical and Physical Properties
The following data are based on typical values for carbide-strengthened Elinvar (after appropriate heat treatment).
| Performance Specifications | Typical Value |
|---|---|
| Tensile Strength | ~1250 MPa |
| Yield Strength | ~1150 MPa |
| Young's Modulus (E) | 177 - 183 GPa |
| Temperature Coefficient of Elastic Modulus (βE) | -3 ~ +3 × 10⁻⁶/℃ |
| Mean Coefficient of Linear Expansion (α) | ~9 × 10⁻⁶/℃ |
| Hardness | 250 - 400 HV |
| Magnetic | Ferromagnetism |
Regarding Magnetism: This aspect distinguishes it from Ni-Span C. Elinvar is ferromagnetic and is therefore unsuitable for use in strong magnetic field environments (such as MRI systems or navigation magnetometers). If your application requires non-magnetic properties, choose Ni-Span C rather than Elinvar.
Targeted Purchase Recommendations (by Status and Usage)
Elinvar's greatest advantage is its suitability for industrial-scale production. However, from a procurement perspective, selecting the wrong material condition can still lead to problems.
Scenario 1: You need to mass-produce watch hairsprings or precision springs (formed via stamping or coiling).
- Recommended Procurement Condition: Cold-Drawn / Cold-Rolled (Work-Hardened)
Why? Components such as hairsprings and mainsprings demand exceptionally high precision in thickness/diameter, as well as superior surface quality. The cold-drawn/cold-rolled condition directly provides:
- Precise dimensional tolerances (±0.01 mm)
- A smooth surface finish (minimizing the need for subsequent polishing)
- Pre-existing strength (allowing for direct use in certain applications without the need for further heat treatment)
- Precise dimensional tolerances (±0.01 mm)
- A smooth surface finish (minimizing the need for subsequent polishing)
- Pre-existing strength (allowing for direct use in certain applications without the need for further heat treatment)
⚠️Note: If your application requires ultimate constant elasticity, material purchased in the cold-drawn condition will still require a subsequent aging treatment. However, after a hairspring has been coiled, it typically undergoes a stress-relief annealing process (at approximately 400°C); this step simultaneously accomplishes a partial aging effect. For specific processing details, please consult your heat treatment engineer.
Scenario 2: You need to process elastic components into complex shapes (e.g., bellows, irregularly shaped spring strips).
- Recommended Procurement Condition: Annealed (Solution-treated)
Why? In the annealed state, the material exhibits excellent elongation, making it suitable for stamping, bending, and deep drawing. After processing, it undergoes age hardening to boost its strength.
⚠️Note: The aging temperature for Elinvar is lower than that of Ni-Span C (approximately 500–600°C), and the resulting dimensional change is also smaller. However, if your component tolerances are at the micron level, you must still account for aging shrinkage (approximately 0.03–0.06%).
Scenario 3: You require a"ready-to-use"elastomer (e.g., a pressure sensor diaphragm).
- Recommended Procurement Condition: Aged + Precision Ground/Polished
Why? You can install it directly upon receipt, saving you the trouble and risk associated with performing heat treatment yourself.
⚠️Note: In its aged state, the material exhibits high hardness; therefore, subsequent finishing operations must be performed via grinding. Lork Group offers precision centerless grinding services, capable of achieving diameter tolerances of ±0.01 mm.
Scenario 4: You require a mechanical filter tuning fork or resonator (where frequency stability requirements are extremely stringent).
- Recommended Procurement Status: Aged + Accompanied by Measured βE Curves
Why? For this specific application, the frequency-temperature coefficient depends directly on the material's βE value. Do not rely on"standard values"; instead, insist on the actual measured data for the specific batch in question.
Notes on ASTM E112:
You may encounter"ASTM E112"in the specifications; this is not a standard exclusive to Elinvar, but rather a standard method for determining the grain size of metallic materials. Suppliers of Elinvar cite this standard to demonstrate that the material's grain size meets the specified requirements (typically Grade 5 or finer). Coarse grain structure leads to increased elastic hysteresis, resulting in a decline in precision.
Traceability Documents Provided by Lork Group:
Original Manufacturer's Material Test Report (CMTR)
Measured βE Curve Across the Full Temperature Range
Grain Size Rating Report (per ASTM E112)
Dimensional Inspection Report
Before placing an order, answer these 4 questions.
Elinvar is relatively low-maintenance, but it should not be purchased blindly. Please answer the following questions (or click the button on the right to contact a technical engineer directly):
Q1: What is your application?
A. Watch Hairsprings/Mainsprings (Requires extremely high precision + extremely low hysteresis)
B. Precision Instrument Springs/Pressure Gauge Tubes (Stable over a wide temperature range)
C. Mechanical Filters/Tuning Forks (Frequency stability is the priority)
D. Other (Please specify)
A. Watch Hairsprings/Mainsprings (Requires extremely high precision + extremely low hysteresis)
B. Precision Instrument Springs/Pressure Gauge Tubes (Stable over a wide temperature range)
C. Mechanical Filters/Tuning Forks (Frequency stability is the priority)
D. Other (Please specify)
Q2: What is your production mode?
A. Mass Production; requires high material property consistency (Recommended: Elinvar)
B. Small-Batch/Prototyping; seeks ultimate performance (Recommended: Ni-Span C)
C. Unsure; advice needed
Q3: Is your operating environment exposed to magnetic fields?
A. Yes (Near MRI machines, navigation equipment, electron microscopes, etc.) → Elinvar is unsuitable; Ni-Span C or 3J58 is recommended
B. No, or magnetic fields are very weak → Elinvar is suitable
Q4: What are your subsequent processing steps?
A. Stamping/Coiling → Recommended: Cold-Drawn/Cold-Rolled condition
B. Turning/Milling/Drilling → Recommended: Annealed condition
C. Direct Assembly → Recommended: Age-Hardened condition + Precision Polishing
Regarding Pricing and Delivery Lead Times
Elinvar is considerably less expensive than Ni-Span C—it contains approximately 8% less nickel and is free of titanium. However, do not compare its price to that of 304 stainless steel; they belong to entirely different price tiers.
Lork Group Reference Price Range (Based on 2026 Market Conditions; Spot Stock):
Annealed Bright Bar: $20–35/kg (MOQ: 50–200 kg)
Cold-Drawn / Cold-Rolled: Price premium of 10–20%
Aged + Precision Ground: Quoted individually based on processing complexity
Cutting Services: We offer precision saw-cutting services with a length tolerance of ±1 mm.
Email: [daisy@lorkgroup.com]
WeChat/WhatsApp: [+ 86 175 1308 1871]
WeChat/WhatsApp: [+ 86 175 1308 1871]
