Hot deformation characteristics of as-cast high-Cr ultra-super-critical rotor steel with columnar grains
来源期刊：International Journal of Minerals Metallurgy and Materials2016年第11期
论文作者：Zong-ye Ding Qiao-dan Hu Long Zeng Jian-guo Li
文章页码：1275 - 1285
摘 要：Isothermal hot compression tests of as-cast high-Cr ultra-super-critical（USC） rotor steel with columnar grains perpendicular to the compression direction were carried out in the temperature range from 950 to 1250°C at strain rates ranging from 0.001 to 1 s-1. The softening mechanism was dynamic recovery（DRV） at 950°C and the strain rate of 1 s-1, whereas it was dynamic recrystallization（DRX） under the other conditions. A modified constitutive equation based on the Arrhenius model with strain compensation reasonably predicted the flow stress under various deformation conditions, and the activation energy was calculated to be 643.92 kJ ×mol-1. The critical stresses of dynamic recrystallization under different conditions were determined from the work-hardening rate（θ）–flow stress（σ） and-θ/σ–σ curves. The optimum processing parameters via analysis of the processing map and the softening mechanism were determined to be a deformation temperature range from 1100 to 1200°C and a strain-rate range from 0.001 to 0.08 s-1, with a power dissipation efficiency η greater than 31%.
Zong-ye Ding1,2，Qiao-dan Hu1,2，Long Zeng1,2，Jian-guo Li1,2
1. School of Materials Science and Engineering,Shanghai Jiao Tong University2. Laboratory of Advanced Materials and Solidification,Shanghai Jiao Tong University
摘 要：Isothermal hot compression tests of as-cast high-Cr ultra-super-critical（USC） rotor steel with columnar grains perpendicular to the compression direction were carried out in the temperature range from 950 to 1250°C at strain rates ranging from 0.001 to 1 s-1. The softening mechanism was dynamic recovery（DRV） at 950°C and the strain rate of 1 s-1, whereas it was dynamic recrystallization（DRX） under the other conditions. A modified constitutive equation based on the Arrhenius model with strain compensation reasonably predicted the flow stress under various deformation conditions, and the activation energy was calculated to be 643.92 kJ ×mol-1. The critical stresses of dynamic recrystallization under different conditions were determined from the work-hardening rate（θ）–flow stress（σ） and-θ/σ–σ curves. The optimum processing parameters via analysis of the processing map and the softening mechanism were determined to be a deformation temperature range from 1100 to 1200°C and a strain-rate range from 0.001 to 0.08 s-1, with a power dissipation efficiency η greater than 31%.
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