Carburising is a thermochemical treatment aimed at hardening steels by adding carbon and increasing surface hardness.
Carburising is a thermochemical treatment aimed at hardening steels by adding carbon and increasing surface hardness. Low-pressure carburising nowadays is an efficient alternative to conventional carburising / carburation techniques, notably bringing about noticeable improvements in homogeneity, penetration and a total absence of intergranular oxidation.
BMI optionally offers the ALLCARB® process for its entire range of high-temperature furnaces (vacuum annealing, vacuum gas quenching and vacuum oil quenching). This technique has been in operation since 1990 in sectors such as aeronautics and the automotive industry. The technique, the use of gas, carburising and the systems are the subject of numerous patents.
The ALLCARB® technique is distinguished by its industrial results: precise, reproducible and homogeneous. Its use is facilitated by a software assistant, which helps to calculate the cycle parameters according to the depth sought and the steel grade. However, the user retains the possibility of modifying them in order to optimise them for his specific application.
Different from the current low-pressure carburising techniques, ALLCARB® perfectly meets industrial constraints:
The carburising gases generally used at low-pressure were replaced by a gas that ensured perfect reproducibility with neither the inconveniences of propane, which does not penetrate thoroughly and forms soot, nor those of methane whose dissociation is difficult to control.
The ALLCARB® technique is handled automatically by a pilot software that determines the progress of the cycle to obtain the desired carbon profile. The choice of temperature is left to the user to optimise the balance between the carburising duration, deformation and dispersion. Atmosphere management is ensured by a vacuum gauge, a pumping unit and mass flow meters. On the basis of four parameters: temperature, steel grade, carburizing depth and surface carbon, the software establishes the pressures, time and outputs to be applied during the cycle.
As a standard, the ALLCARB® technique is planned for an injection-controlled single-sequence operation but can also be used in a multi-boost mode (series of enrichment phases).