The effect of processing parameters on the dynamic recrystallisation behaviour of API-X70 pipeline steel
The effect of deformation temperature and strain rate on the dynamic recrystallisation (DRX) behaviour of X70 pipeline steel was investigated. DRX parameters such as the critical and peak stresses and strains as well as the deformation activation energy were determined in the temperature range between 925°C and 1125°C for strain rates of 0.1, 1 and 5s-1. The relationship between the peak stresses and strains with the Zener-Hollomon parameter was determined. The dynamically recrystallised volume fraction was computed as a function of the different temperatures and strain rates. The APRGE software was applied for the first time on electron back-scattering diffraction data of dynamically recrystallised microstructures in order to reconstruct the prior austenite from the as-quenched martensite phase. The dynamically recrystallised flow stress curves and microstructure were also predicted using cellular automata modelling. The results show an earlier onset of DRX with a decrease in strain rate or an increase in deformation temperature. The dynamically recrystallised grain size is also found to decrease with an increase in strain rate and a lowering of deformation temperature. © 2013 Elsevier B.V.
Keywords: Activation energy ; Backscattering ; Cellular automata ; Cellular automata modelling ; Deformation ; Deformation activation energy ; Deformation temperatures ; Diffraction ; Dynamic recrystallisation ; Elasticity ; Electron back-scattering diffraction ; Electron backscattering diffraction ; Grain reconstruction ; Microstructure ; Pipeline steel ; Recrystallization (metallurgy) ; Steel pipe ; Strain rate ; Structural design ; Thermo-mechanical processing ; Zener-Hollomon parameter
Record created on 2014-11-14, modified on 2016-08-09