Forgeabilité des aciers inoxydables austéno-ferritiques

tel-00672279, version 1 - 21 Feb 2012
Table of contents 1
Table of contents
Remerciements ...................................................................................... i
Abstract ............................................................................................... vii
Table of contents .................................................................................. 1
List of symbols ...................................................................................... 7
Chapter I. Introduction: scientific and industrial motivations ......... 11
I.1 Industrial motivations .............................................................................. 12
I.2 Materials and microstructures ................................................................ 14
I.2.1 Materials investigated .......................................................................................14
I.2.2 Microstructures after continuous casting ...........................................................15
I.2.3 Microstructures during hot rolling ......................................................................16
I.2.3.1 The hot rolling process ............................................................................................ 16
I.2.3.2 Microstructures after the roughing-mill operations .................................................. 17
I.2.3.3 Microstructures in the vicinity of the edges ............................................................. 18
I.3 Guideline ................................................................................................... 18
Chapter II. State of the art regarding the hot working of duplex
stainless steels ................................................................................... 21
II.1 Microstructural evolution during hot working ....................................... 22
II.1.1 As-cast microstructure ......................................................................................22
II.1.2 Changes in morphology and distribution of the dispersed γ-austenite................23
II.1.2.1 Interphase boundary sliding .................................................................................... 24
II.1.2.2 Rotation ................................................................................................................... 25
II.1.2.3 Shear banding ......................................................................................................... 26
II.1.3 Plastic deformation ............................................................................................27
II.2 Mechanical behaviour during hot working ............................................ 28
II.2.1 Viscoplastic hardening laws: influence of temperature and strain rate ...............28
II.2.2 Influence of the chemical composition ...............................................................30
II.2.2.1 Volume fraction of phases ...................................................................................... 30
II.2.2.2 Influence of alloying elements and element partitioning ......................................... 32