Masselin is the proud manufacturer of the largest spring in the world!.

Gros ressort

In spite of its huge size, this part must still maintain tight tolerances and is subject to the strictest tests.
Generally, a spring of this size is used by subsea actuators to open or close the valves on oil drilling platforms. With safety the main concern, there is no margin for error.
We also produce medium-sized and small parts, always with the same high level of precision, and are the only French manufacturer to be RCCM approved.




We produce parts for use in the following sectors:

  • Nuclear (RCCM springs in accordance with level 1, 2 or 3 standard and ASME): valve springs, uranium door mechanisms for use in the reactor core, earthquake-resistant boxes.
  • Hydraulic: turbines, locks.
  • Electric: medium and high voltage, springs for use in circuit breakers, anti-vibration systems for wind turbines.
  • Oil and gas: springs for use in valve actuators, leaves for prospecting for oil.

Our design office will help you develop new parts, basing its suggestion for the right spring on your requirements.

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Familles de produits


We cover the full range of springs :

  • Compression
  • Tension
  • Torsion
  • Spring washers
  • Rings
  • Torsion bars / anti-roll bars
  • Shaped Springs, flat or from wire
Images familleDeProduits
Ressorts à bouts retrains
Ressort à pas variable
Ressort pour actionneur
Ressort à béquets droits
Ressort à béquet droits
Ressort de soupape avec rondelle
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Parts undergo testing in our workshop to ensure that they meet the strictest requirements for the greatest reliability :

  • Hardness testing
  • Size testing
  • Lengths under load and vertical stiffness
  • Non-destructive test (magnetic particle inspection, dye penetrant inspection etc.)
  • Metallographic testing (metallurgical structure, decarburisation etc.)
  • Shot peening intensity measurements
  • Failure analysis with research into the cause of rupture, if required

Raw materials :

For medium and large-sized springs, (Ø 18–97 mm), we use low alloy steels 51CrV4 and 52CrMoV4 in accordance with the standard EN 10089. Ultra-sonic testing is available on request to detect any internal defect. For smaller springs, there is the option of using stainless steels, nickel-based alloys (Inconel, Nimonic etc.), titanium (Grade 5 Ti-6Al-4V), copper beryllium (CuBe2) etc.

Protection against corrosion :

We have a powder coating facility and a liquid paint plant to ensure that our products are treated with the best possible protection against corrosion.

Double-layer paint provides 1500 hours of resistance to salt spray.