Microstructure evolution of hot-work tool steels during tempering and definition of a kinetic law based on hardness measurements

Abstract : Microstructural evolutions of the 55NiCrMoV7 steel during tempering were investigated by transmission electron microscopy, scanning electron microscopy and X-ray diffraction in order to describe the main mechanisms of softening. The softening resistance is strongly associated with evolution of obstacles to the movement of dislocations (prior austenitic grain boundary, lath boundary, secondary carbides, etc.). Only the average size of carbides was found to be influenced by tempering conditions. Moreover, a strong correlation observed between the hardness measured after tempering and the average size of carbides showing that this easy test could in this case partially characterize the state of the microstructure after tempering. Performing hardness measurements at the as-quenched, tempered and annealed states, a kinetic law of tempering based on the work of Johnson, Mehl and Avrami has been proposed. This law was validated in the case of complex tempering and for other steels and can well describe the evolution of hardness during tempering.
Type de document :
Article dans une revue
Materials Science and Engineering: A, Elsevier, 2004, 380 (1-2), pp.222-230. 〈10.1016/j.msea.2004.03.067〉
Liste complète des métadonnées

https://hal.archives-ouvertes.fr/hal-01715086
Contributeur : Imt Mines Albi Ecole Nationale Supérieure Des Mines d'Albi-Carmaux <>
Soumis le : jeudi 22 février 2018 - 12:45:24
Dernière modification le : lundi 6 août 2018 - 15:03:05

Identifiants

Collections

Citation

Z Zhang, Denis Delagnes, Gérard Bernhart. Microstructure evolution of hot-work tool steels during tempering and definition of a kinetic law based on hardness measurements. Materials Science and Engineering: A, Elsevier, 2004, 380 (1-2), pp.222-230. 〈10.1016/j.msea.2004.03.067〉. 〈hal-01715086〉

Partager

Métriques

Consultations de la notice

29