Giving strength to matter.

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THERMILYON Group specializes in heat treatment and vacuum coatings for mechanical engineering.

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Improve the mechanical performance of your parts

A true pioneer in contract heat treatment for the subcontracting industries, the THERMILYON group has been capitalizing on technical innovation and service provision in heat treatment and vacuum deposition since 1960.

With a network of eight sites in France and abroad, the THERMILYON Group prioritizes close relationships with its partners and actively listens to understand their needs and challenges.

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Solutions tailored to your needs

To ensure that our advice is always well-informed and objective, the THERMILYON Group offers a wide range of solutions to provide treatment adapted to the environment and constraints of the room.

Heat treatment
Heat treatment
parts partially coated with platin vacuum coating
Vacuum deposition
Vacuum deposition
1960

Year the THERMI-LYON Group was founded

5000

More than 5,000 customers in France and abroad

32

Millions of euros in sales

20

Millions of euros in human and technological investment over the past 4 years

165

employees

100

100% of our sites are certified

expertise in every market

To meet the expectations and requirements of certain markets, our sites are specialized and organized by market sector.

Customer testimonials

Cédric Lancieux

Technical Director, Euroteknika 

"We needed to call on a company skilled in vacuum coating to ensure lasting quality for our products. It was thequality aspect that drew me back to them. We make products that stay in patients' mouths; quality is paramount in our business, and it's an aspect that Thermi-Platin more than lived up to. What Euroteknika needs is to differentiate itself in the market, and the coating produced by Thermi-Platin is a differentiator. Today, they are even proactive and solution-oriented. They come to us with real answers."

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Portrait of Cédric Lancieux, Euroteknika employee

Claude Madelmont

Borg Warner Supplier Selection Manager

"We specialize in what's known as the powertrain; that's everything to do with the engine and transmission. These parts have electromagnetic and wear-resistance characteristics. This is a very important point. The THERMILYON Group specializes in controlled atmosphere nitrocarburizing. This involves heat-treating the part to make it harder and more resistant to wear. This is a state-of-the-art treatment. Trempelec processes 15,000 to 25,000 partsat a time".

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Portrait of Claude Madelmont, Borgwarner collaborator

Damien Pignol

Methods and Supply Chain Engineer at Lisi Aerospace Additive Manufacturing

"When it comes to research and development aimed at creating new treatments to meet emerging challenges, Thermi-Garonne clearly stands out for its receptiveness and ability to propose innovative solutions, setting itself apart from the competition.
Thermi-Garonne's uniqueness lies in its 100% management of LISI Aerospace Additive Manufacturing parts."
As for the service offered by Thermi-Garonne, Damien Pignol expresses great satisfaction, ranking them among the top three suppliers for the company.

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lisi aerospace logo

Jérôme Lefebvre

Purchasing manager at ERMO-tech

"We specialize in the cosmetics, pharmaceuticals, medical and fine wall sectors, as well as in high-precision, high-speed closures. Thermi-Platin treats certain parts of our molds to extend their service life. All contact, friction and sliding between parts need to be hardened with DLC, a surface coating. Today, we have an average lead time of 3 days with Thermi-Platin. Thermi-Platin has been able to offer relevant products and prove its responsiveness to the needs of the ERMO group. They also provide us with a partner and technical support in our search for solutions.

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    Our partners

    fim logo
    logo uimm auvergne rhone alpes
    logo of A3TS, the association for heat treatment and surface treatment
    logo cluster aeronautique auvergne rhone alpes
    logo cluster aeronautique aerospace valley
    logo member of the Astech cluster
    woman looking through a microscope
    loading a nitrex nitriding furnace at Thermi-Picardie

      Our locations near you

      Trempelec
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      Thermi-Loire
      • 143 Avenue Benoît Fourneyron 42160 ANDRéZIEUX-BOUTHéON
      • +33477555230
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      Thermi-Garonne
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      Thermi-Bugey
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      Thermi-Picardie
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      Thermi-Metalurgica
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      Thermi-Lyon
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      Thermi-Platin
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      Discover the thermilyon group

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      Our certifications

      ISO 13485
      ISO 13485 certification logo

      ISO 13485 establishes the criteria for the quality management system of an organization providing medical devices and related services in compliance with customer requirements and applicable regulations.

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      EN 9100

      EN 9100 certification guarantees the quality management system requirements of the ISO 9001 series, and specifies additional definitions and notes for the aerospace and defense industry.

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      IATF 16949
      logo IATF 16949 certification dedicated to the automotive industry

      The IATF 16949 standard, dedicated to the automotive sector, establishes criteria for quality management processes, encouraging continuous improvement, defect prevention and the reduction of non-conformities and scrap within the automotive supply chain.

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      NADCAP Heat Treating
      logo nadcap heat treating

      NADCAP is an accreditation program for aerospace and defense subcontractors, designed to ensure the quality and reliability of products and services. This accreditation focuses on the special processes employed in the manufacture, testing and maintenance of components and systems used in these industries. Within the THERMILYON Group, NADCAP applies only to the special heat treatment process.

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      ISO 9001

      The ISO 9001 standard, widely recognized throughout the world, helps organizations improve their performance by meeting quality management system requirements and demonstrating a commitment to customer satisfaction.

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      See all our certifications

      Increase the performance of your parts

      The THERMILYON Group is your partner for improving your mechanical parts. Our teams will help you choose the treatment best suited to your needs.

      Contact us

      Our latest news

      Find out all the latest news about the THERMILYON Group as well as heat treatment and vacuum deposition.

      What are the implications of certifications for heat treatment in the aerospace industry?
      In the aerospace industry, every component must meet extreme standards for safety, performance, and reliability. Heat treatment plays a central role in achieving the desired mechanical properties, but it cannot be carried out without a strict framework for control and validation. This is where certifications and […] come into play.
      March 26, 2026
      What are the implications of certifications for heat treatment in the aerospace industry?
      Vacuum Deposition and Heat Treatment: Toward Ever More Effective Solutions?
      In an industrial landscape characterized by ever-increasing demands for reliability, durability, and performance, manufacturers are seeking solutions capable of optimizing the performance of their mechanical components. Heat treatment and vacuum coating have emerged as key technological solutions for addressing these challenges. Whether the goal is to increase […]
      May 7, 2026
      Vacuum Deposition and Heat Treatment: Toward Ever More Effective Solutions?
      stainless steel components requiring appropriate heat treatment
      What heat treatments are used for stainless steel components?
      Stainless steels are a family of materials that are essential in a wide range of industrial sectors, including medical, aerospace, automotive, tools, energy, and electronics. Their properties make them indispensable for critical components. However, even a material as high-performance as stainless steel requires considerable expertise to achieve its optimal performance. This is where treatments come in.
      March 2, 2026
      What heat treatments are used for stainless steel components?
      aerospace mechanical workshop in the Paris region
      Heat treatment in Île-de-France, a key driver for the performance of aerospace industry players
      With the presence of manufacturers, engine builders, equipment suppliers, and maintenance centers, the Île-de-France region occupies a strategic position in the European aerospace industry. In this environment, where every component must guarantee absolute safety, mastery of heat treatment in Île-de-France has become an essential factor in performance. Metal parts designed to fly, withstand [...]
      February 23, 2026
      Heat treatment in Île-de-France, a key driver for the performance of aerospace industry players
      How does vacuum deposition improve resistance to friction and wear?
      In many industrial sectors, component wear remains one of the main causes of reduced performance, premature failure, and additional maintenance costs. Faced with these constraints, the use of vacuum coatings has emerged as a leading technological solution for improving the durability of parts subjected to repeated friction. Thanks to […]
      February 2, 2026
      How does vacuum deposition improve resistance to friction and wear?
      tray containing medical devices made of steel and heat treated
      The role of heat treatment in extending the service life of medical components
      In the medical sector, every instrument, implant, or assembly component must guarantee an impeccable level of reliability. Parts are subjected to demanding conditions: constant contact with the human body, exposure to chemical agents, repeated mechanical stress, and intensive sterilization cycles. To ensure consistent performance over time, it is […]
      January 21, 2026
      The role of heat treatment in extending the service life of medical components