A Thermo-Metallurgical Model for Steel Cooling Behaviour : Proposition, Validation and Comparison with the Sysweld's Model

the aim of this work is to include the metallurgical behaviour of steels (and specifically their phase transformations) into thermo-mechanical studies. In this purpose, a new model of anisothermal phase transformations during the cooling stage is proposed. Developed in the thermodynamics framework of simple materials with memory variables, its originality lies in the choice of the temperature time derivative T' as an independent variable. The identification and the transformation rates computation use the CCT diagrams which are considered as families of particular solutions of evolution equations. The validation shows ability of the model to simulate all CCT deductible tests. Furthermore, for some tests not included into the CCT the numerical results remain good and the model, from which evolution equation form as been let free, allows to incorporate them to the identification data without modifying the CCT simulation accuracy. Lastly, for all the previous tests, this model has been compared with the one of the Sysweld software