The hot deformation behavior and microstructure evolution of industrial grade American Iron and Steel Institute(AISI)M35 high-speed steel produced by electroslag remelting at different parameters were investigated.The...The hot deformation behavior and microstructure evolution of industrial grade American Iron and Steel Institute(AISI)M35 high-speed steel produced by electroslag remelting at different parameters were investigated.The results indicated that grains coarsening and M2C carbides decomposing appeared in the steel at 1150℃for 5 min,and the network carbides were broken and deformed radially after the hot deformation.A constitutive equation was determined based on the corrected flow stress-strain curves considering the effects of friction and temperature,and a constitutive model with strain-compensated was established.The dynamic recrystallization(DRX)characteristic values were calculated based on the Cingara-McQueen model,and the grain distribution under different conditions was observed and analyzed.Significantly,the action mechanisms of carbides on the DRX were illuminated.It was found from a functional relation between average grain size and Z parameter that grain size increased with increasing temperature and decreasing strain rate.Optimal parameters for the hot deformation were determined as 980-1005℃~0.01-0.015 s^(−1)and 1095-1110℃~0.01-0.037 s^(−1)at the strain ranging from 0.05 to 0.8.Increasing the strain rate appropriately during deformation process was suggested to obtain fine and uniformly distributed carbides.Besides,an industrial grade forging deformation had also verified practicability of the above parameters.展开更多
Thermodynamics and kinetics of dissociation and precipitation of MnS inclusions,as well as the effect of reoxidation in liquid steel on MgO·Al_(2)O_(3)inclusions in AISI M35 steel during electroslag remelting(ESR...Thermodynamics and kinetics of dissociation and precipitation of MnS inclusions,as well as the effect of reoxidation in liquid steel on MgO·Al_(2)O_(3)inclusions in AISI M35 steel during electroslag remelting(ESR)process were investigated.The inclusions found in the consumable electrode were MnS,MgO·Al_(2)O_(3)and MnS adhering to MgO·Al_(2)O_(3).MnS inclusions were nearly spherical and ellipse in morphology,and most of them were less than 2μm in size.MgO·Al_(2)O_(3)inclusions were polygonal and nearly spherical and most about 1-4μm in size.The inclusions in ESR ingot observed by scanning electron microscopy-energy-dispersive X-ray spectrometer were polygonal and nearly spherical MgO·Al_(2)O_(3).MnS inclusions in the consumable electrode were completely dissociated before the liquid film dripping into molten slag pool.The controlling step of MnS inclusions dissociation was the mass transfer of[Mn]in the liquid steel.During the solidification process,the thermodynamic driving force could not meet MnS inclusions precipitation before the solid fraction exceeds 0.996,and the kinetics condition is too poor for the growth of MnS inclusions in the steel when the solid fraction is larger than 0.996.MgO·Al_(2)O_(3)inclusions in ESR ingot originated from the remained MgO·Al_(2)O_(3)inclusions in consumable electrode and the fresh ones formed by the reaction between dissolved magnesium,oxygen and aluminum in liquid steel.展开更多
基金support from Open Project of State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing(No.41622030)Danyang Coinch New Material Technology Co.,Ltd.
文摘The hot deformation behavior and microstructure evolution of industrial grade American Iron and Steel Institute(AISI)M35 high-speed steel produced by electroslag remelting at different parameters were investigated.The results indicated that grains coarsening and M2C carbides decomposing appeared in the steel at 1150℃for 5 min,and the network carbides were broken and deformed radially after the hot deformation.A constitutive equation was determined based on the corrected flow stress-strain curves considering the effects of friction and temperature,and a constitutive model with strain-compensated was established.The dynamic recrystallization(DRX)characteristic values were calculated based on the Cingara-McQueen model,and the grain distribution under different conditions was observed and analyzed.Significantly,the action mechanisms of carbides on the DRX were illuminated.It was found from a functional relation between average grain size and Z parameter that grain size increased with increasing temperature and decreasing strain rate.Optimal parameters for the hot deformation were determined as 980-1005℃~0.01-0.015 s^(−1)and 1095-1110℃~0.01-0.037 s^(−1)at the strain ranging from 0.05 to 0.8.Increasing the strain rate appropriately during deformation process was suggested to obtain fine and uniformly distributed carbides.Besides,an industrial grade forging deformation had also verified practicability of the above parameters.
基金The financial support by the National Natural Science Foundation of China(Grant No.52104339)the Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking(Grant No.KF-20-3)are greatly acknowledged.
文摘Thermodynamics and kinetics of dissociation and precipitation of MnS inclusions,as well as the effect of reoxidation in liquid steel on MgO·Al_(2)O_(3)inclusions in AISI M35 steel during electroslag remelting(ESR)process were investigated.The inclusions found in the consumable electrode were MnS,MgO·Al_(2)O_(3)and MnS adhering to MgO·Al_(2)O_(3).MnS inclusions were nearly spherical and ellipse in morphology,and most of them were less than 2μm in size.MgO·Al_(2)O_(3)inclusions were polygonal and nearly spherical and most about 1-4μm in size.The inclusions in ESR ingot observed by scanning electron microscopy-energy-dispersive X-ray spectrometer were polygonal and nearly spherical MgO·Al_(2)O_(3).MnS inclusions in the consumable electrode were completely dissociated before the liquid film dripping into molten slag pool.The controlling step of MnS inclusions dissociation was the mass transfer of[Mn]in the liquid steel.During the solidification process,the thermodynamic driving force could not meet MnS inclusions precipitation before the solid fraction exceeds 0.996,and the kinetics condition is too poor for the growth of MnS inclusions in the steel when the solid fraction is larger than 0.996.MgO·Al_(2)O_(3)inclusions in ESR ingot originated from the remained MgO·Al_(2)O_(3)inclusions in consumable electrode and the fresh ones formed by the reaction between dissolved magnesium,oxygen and aluminum in liquid steel.
