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Home Controlled gas cementation

gas cementation

Objective: precise control of cemented layer characteristics and depth.

Gas carburizing, a crucial heat treatment, enriches the steel's surface layer with carbon, essential for increasing wear and fatigue resistance at the surface. This process can also incorporate nitrogen for carbonitriding, increasing surface hardness while maintaining good core mechanical properties. Hardening, carried out after case-hardening, is essential to achieve high hardness performance and durability, while controlling the deformations associated with rapid cooling and martensitic transformation.

Traditionally carried out in a nitrogen-methanol atmosphere, Thermi-Lyon's innovative Thermi-Carb® gas carburizing process uses a controlled mixture of active gases (such as CH4) and air, optimizing carbon diffusion and the gaseous phase of the treatment. The process is computerized for precise parameter control, ensuring excellent control of operations and results in an industrial environment.

automatic oven line trempelec, bach oven

Our process

Depending on the number, size and configuration of parts, and the desired treatment depth, various types of furnace are used, such as pot furnaces, batch furnaces (with integrated quench tank), and conveyor furnaces. The "Thermi-Carb®" process, specially developed by the THERMILYON Group, is particularly well suited to pot and batch furnaces, optimizing carburizing and carbonitriding of mechanical components. A nitrogen-methanol atmosphere is traditionally used for belt furnaces, favoring high-precision heat treatment.

01

Pressure and temperature control

The treatment is carried out at slightly above atmospheric pressure, operating at high temperatures of 900 to 940°C for carburizing and 820 to 900°C for carbonitriding. These precise settings produce a high-quality case-hardened layer, increasing mechanical strength and surface hardness while minimizing the risk of inter-granular oxidation.

02

Continuous management

An advanced computer system continuously monitors crucial process parameters such as time, temperature and composition of the active atmosphere. The use of an oxygen probe or an infrared analyzer for CO and CO2 enables precise calculation of the carbon potential, ensuring uniformity of the surface layer and consistent quality of surface and core mechanical characteristics, tailored to each steel grade.

03

Recommendations

For mild and medium-hard steels (C10 to C45, A40 to A60), case-hardening is generally not recommended due to their low hardenability, which can lead to incompatibilities between core and surface hardness, as well as heterogeneities in the case-hardened layer. Carbonitriding, on the other hand, is recommended for free-cutting steels such as C10, S300 and S300 Pb, as the addition of nitrogen during this process enables higher surface hardnesses to be achieved, offering improved wear resistance.

    Features and benefits

    Gas carburizing significantly improves surface wear and fatigue resistance, while maintaining excellent core strength properties. This method, which focuses on enriching the surface layer of metals with carbon, also enhances the durability and performance of treated components.

    Mechanical resistance

    Thermi-Lyon's case-hardening and carbonitriding processes deliver high levels of wear, seizure and fatigue resistance, even in low-cost steels with good machinability. This approach guarantees high quality and reliability for a wide range of industrial applications, including demanding sectors such as automotive and public works.

    Precision

    We offer high precision and reliability in the reproduction of heat treatments, thanks to our mastery of advanced techniques and the diversity of technologies adapted to different types of parts, including pot, batch and belt furnaces. These technologies ensure consistent, cost-effective results, boosting competitiveness in the marketplace.

    Deformation control

    Uniformity of the treated layer and controlled depth of treatment are essential to maintain hardening performance. Martensitic transformation can lead to dimensional variations; however, the rigorous control of our Thermi®-Carb process, in combination with the latest generation of oil quenching devices, minimizes these deformations. This level of control is crucial to ensuring the quality and precision of processed parts, enhancing their durability and operational efficiency.

    For study and order

    Information to be communicated :

    Type of treatment: case-hardening or carbonitriding.

    - Drawing of the part, specification, weight, number of parts per shipment and per year.
    - Nature of the metal. Preferred AFNOR or commercial designation.
    - Conventional depth and surface hardness (core hardness results from steel grade).
    - Deformation tolerance (with possible straightening and allowance for finish machining).

    Ask for a quote

    business sectors concerned

    Gaseous carburizing and carbonitriding are widely used for mechanical parts subjected to fatigue and friction (wear resistance and seizure).

    Aerospace
    Aerospace market
    Automotive
    Automotive market
    Rail energy
    Rail energy market
    Machines and components
    Machinery and components market
    Medical
    Medical market
    Tools
    Tools market
    Sports and leisure
    Sports and leisure market
    Public works
    Public works contract

      Our various documentations

      Heat treatment white paper
      Thermilyon Group white paper on metal heat treatmentRead more
      Atmospheric carburizing with Thermi-Carb
      automatic oven line trempelec, bach ovenRead more
      See all our certifications

      Our FAQs

      What is the advantage of carburizing / carbonitriding?

      Diffuse carbon (carbon and nitrogen in the case of carbonitriding) on the surface of the part, to considerably improve the part's mechanical strength and wear resistance on the surface, while maintaining good core strength.

      What is heat treatment?

      It's an operation that modifies the internal structure of an alloy to change its properties. In general, there are 3 phases: heating, holding at temperature and slow or rapid cooling (in this case called quenching).

      What is the advantage of atmospheric treatment?

      Atmospheric heat treatment enables the use of low-cost steels. Atmospheric technologies are ideal for large-scale production runs and large dimensions.

      What machining allowances need to be taken into account for heat treatment operations?

      Heat treatment reveals different levels of stress from previous stages (manufacturing). These stress relaxations can lead to deformations that must be anticipated at the time of machining. In the case of heat treatment in the mass (quenching, tempering), these extra thicknesses depend on the dimensions of the part, but are of the order of a few tenths to 1 mm.

      To limit the level of deformation, it is advisable to carry out a stabilization treatment on the blank.

      See all FAQs

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      Our dedicated team will get back to you.

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