| 30Cr1Mo1V steel is a kind of heat resistant alloy steel,which has excellent high temperature strength and good hardenability.It is a common material for manufacturing high and medium pressure rotor of steam turbine.But there are still some problems in the production process,such as product cracking,low qualified rate and so on.Therefore,it is necessary to study the high temperature deformation and hot ductility of the alloy.In this paper,30Cr1Mo1V steel as forged state is taken as the research object,and the hot tensile test is carried out by using the thermal simulation testing machine to obtain the hot tensile stress-strain curve when the deformation temperature is 750?1250?and the strain rate is 0.01?1s-1.Based on the analysis of the obtained stress data,the effects of deformation temperature and strain rate on the peak stress and peak strain were discussed,and a modified Arrhenius constitutive model was established to describe the high temperature rheological behavior of the alloy.The results show that the fracture mode of the alloy is ductile fracture when the deformation temperature is 750?1250?.When the deformation temperature is750?1050?,the hot plasticity of 30Cr1Mo1V steel increases with the increase of deformation temperature and the decrease of strain rate.When the deformation temperature is 1050?1250?,the hot ductility is higher,which is close to 100%.The microstructure and evolution of 30Cr1Mo1V steel were observed and analyzed by means of metallography,scanning electron microscope and electron backscatter diffraction,in order to explore the influencing factors of the hot ductility of 30Cr1Mo1V steel.The results show that the hot ductility of 30Cr1Mo1V steel is affected by the original austenite grain size,deformation temperature and strain rate when the deformation temperature is 750?1250?and strain rate is 0.01?1s-1 Among them,dynamic recrystallization has the most significant effect on the improvement of hot ductility. |
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