An innovative multiscale numerical framework to design industrial quenching process safely – INFINITY

Quenching processes of metals are widely adopted procedures in the industry, in particular automotive, nuclear and aerospace industries since they have direct impacts on changing mechanical properties, controlling microstructure and releasing residual stresses. Today there is a strong demand from many industrial companies to control this cooling process taking into account realistic quenching environments with their complexity in order to obtain the desired metallurgical properties such as hardness and yield strength. This demand is accented by the severe requirements in shorter deadlines to design new materials and high quality product. Indeed, the mastering of the cooling rates respecting the metallurgical route with a good homogeneity and reliability is essential to achieve the required microstructure and the mechanical performance.

The numerical simulation is a quite standard tool in the framework of metallurgical industry for forming processes but at this time no software is enough predictable ensuring precise heat transfer between the quenching environments and the treated part. A precise numerical multiscale modeling that offers detailed understanding of the complex behavior of multiphase fluid flow and its impact on the part cooling is then a subject of major importance. Indeed, it allows first to reduce the time and cost of developing new materials and therefore to continually develop safe and reliable products that meet the customer specifications and second, to improve the design of existing or new quenching devices, limiting production costs and decreasing energy consumption.

Despite the evident industrial interest for modeling precisely quenching process during alloy heat treatment, there is no global study neither global answer addressing this problem in an industrial context. Therefore, the INFINITY partners: ARCELORMITTAL, AREVA NP, AUBERT & DUVAL, CEFIVAL, CMI, FAURECIA, INDUSTEEL, LISI AEROSPACE, MONTUPET, SAFRAN, SCC and TSV, have decided to structure their needs by supporting the following chair proposal.

Indeed, in order to predict precisely the liquid-to-vapor phase transition during boiling as well as to study the optimal combinations of quench parameters to reduce residual stresses in solid ingots, an innovative coupled numerical framework needs to be designed and implemented. We believe that achieving this breakthrough requires first the development of a unified ground-breaking adaptive finite element numerical strategy attended by experimental validations under well-defined and controlled conditions and, second, the development of an immersed multiphase strategy in order to leverage the simplicity and flexibility of fluid-solid-heat coupling.

Through the INFINITY chair, the candidate and the involved researchers propose, thanks to a very promising immersed volume method, to consolidate a unified multiscale framework around this purpose and to integrate this work and capitalize it in the finite element software THOST® . Modeling the liquid-to-vapor phase change, predicting different boiling modes with the transition between them and modeling the fluid-solid-heat coupling with solid phase transformation are mainly aimed. Two main representative quenching environments will be considered: immersed quenching and jet quenching. Moreover a large part of the proposed work will be also dedicated to experimental investigations and validations.

The INFINITY chair contributes then to a long-term vision of high fidelity numerical tool as a basis for reliable simulations of quenching processes allowing the partners to remove several major technical barriers, to faster aid to decision for delivering high quality parts while minimizing residual stresses, preventing cracking and thus optimizing heat processes.