The effects of Ni content and heat-treatment process on the toughness of a super ferritic stainless steel with 26 wt% Cr and 3.5 wt% Mo were investigated. It was found that with the increase of Ni content, the Charpy ...The effects of Ni content and heat-treatment process on the toughness of a super ferritic stainless steel with 26 wt% Cr and 3.5 wt% Mo were investigated. It was found that with the increase of Ni content, the Charpy impact toughness improved remarkably, and transformed from cleavage brittle fracture to the most ductile fracture. There were no obvious differences between the high- and low-Ni contents on the microstructure and mechanical properties since the addition of Ni did not influence crystal structure, phase composition, and precipitation of ultra pure ferritic stainless steels. Meanwhile, the heat-treatment process was a key point to maintain a high level of toughness by optimizing structure and removing detrimental precipitation, i.e., chi phase.展开更多
The hot deformation behavior and microstructure evolution of an Fe–30Cr–2Mo ultra-pure super ferritic stainless steel were investigated at the temperature range of 950–1150℃ and strain rate varying from 0.01 to 10...The hot deformation behavior and microstructure evolution of an Fe–30Cr–2Mo ultra-pure super ferritic stainless steel were investigated at the temperature range of 950–1150℃ and strain rate varying from 0.01 to 10 s^(−1).A strain compensated constitutive equation based on the Arrhenius-type model was established to predict the flow stress.The hot processing map based on the dynamic materials model was achieved to identify the optimum processing parameters.In addition,the features of microstructure evolution combined with the processing map were systematically investigated.The experimental results revealed that the flow stress increased with decreasing deformation temperature or increasing strain rate.Dynamic recovery was confirmed to be the predominant softening mechanism.The values of flow stress predicted by the strain compensated constitutive equation agreed well with the experimental values.The extent of dynamic recrystallization and recrystallized grain size increased with increasing deformation temperature or decreasing strain rate,and the continuous dynamic recrystallization was attributed to be the predominant mechanism of recrystallization during hot deformation.The optimum hot working parameters were determined to be the deformation temperature of 1070–1150℃ and strain rate of 0.1–1 s^(−1) with a peak power dissipation efficiency of 42%.展开更多
文摘The effects of Ni content and heat-treatment process on the toughness of a super ferritic stainless steel with 26 wt% Cr and 3.5 wt% Mo were investigated. It was found that with the increase of Ni content, the Charpy impact toughness improved remarkably, and transformed from cleavage brittle fracture to the most ductile fracture. There were no obvious differences between the high- and low-Ni contents on the microstructure and mechanical properties since the addition of Ni did not influence crystal structure, phase composition, and precipitation of ultra pure ferritic stainless steels. Meanwhile, the heat-treatment process was a key point to maintain a high level of toughness by optimizing structure and removing detrimental precipitation, i.e., chi phase.
基金This work is supported by the Liaoning Province Programs of Science and Technology Development(No.2019JH2/10100009).
文摘The hot deformation behavior and microstructure evolution of an Fe–30Cr–2Mo ultra-pure super ferritic stainless steel were investigated at the temperature range of 950–1150℃ and strain rate varying from 0.01 to 10 s^(−1).A strain compensated constitutive equation based on the Arrhenius-type model was established to predict the flow stress.The hot processing map based on the dynamic materials model was achieved to identify the optimum processing parameters.In addition,the features of microstructure evolution combined with the processing map were systematically investigated.The experimental results revealed that the flow stress increased with decreasing deformation temperature or increasing strain rate.Dynamic recovery was confirmed to be the predominant softening mechanism.The values of flow stress predicted by the strain compensated constitutive equation agreed well with the experimental values.The extent of dynamic recrystallization and recrystallized grain size increased with increasing deformation temperature or decreasing strain rate,and the continuous dynamic recrystallization was attributed to be the predominant mechanism of recrystallization during hot deformation.The optimum hot working parameters were determined to be the deformation temperature of 1070–1150℃ and strain rate of 0.1–1 s^(−1) with a peak power dissipation efficiency of 42%.
