The relationship between microstructures and mechanical properties of a medium carbon V-N microalloyed steel used for N80 seamless oil-well tubes of hot rolling non-quenched/tempered(non-Q and T)was investigated.The r...The relationship between microstructures and mechanical properties of a medium carbon V-N microalloyed steel used for N80 seamless oil-well tubes of hot rolling non-quenched/tempered(non-Q and T)was investigated.The results have shown that volume percentages of upper bainite,modified bainite and ferrite have a decisive influence on impact energies of steel tubes.When the total volume percentage of bainite is larger than 5%,the impact energy of tubes can not satisfy with the industrial criteria.Moreover,if the total volume percentage of bainite is smaller than 5%,then the impact energy of steel tubes enhances with volume percentage of ferrite increasing.The final microstructures have closely relation with tube billet quality,controlled cooling temperature after tube rolling and cooling method after stretch-reduction-diameter.High quality of medium carbon V-N microalloyed steel for non-Q and T oil-well tubes can be produced through comprehensive control of microstructures and mechanical properties in sub-procedures,especially for tube billet quality and controlled cooling parameters.展开更多
Based on test data from the hot forge experiments on Gleeble 1500, a Kumar type constitutive equation for 33Mn2V steel is established. Applying this constitutive equation in commercial FEM software of MSC/SuperForm 20...Based on test data from the hot forge experiments on Gleeble 1500, a Kumar type constitutive equation for 33Mn2V steel is established. Applying this constitutive equation in commercial FEM software of MSC/SuperForm 2005, the piercing process of 33Mn2V steel in Mannesmann mill is then simulated. The modeling results visualized the dynamic evolution of equivalent stress, especially inside the workpieee. It is shown that the non-uniform distribu- tion of stress on the internal and external surface of the workpiece is a distinct characteristic of processing tube pierc- ing. The numerical model was verified by comparing the values of calculated force parameters of the piercing process with those measured in laboratory eonditions. And it shows that the Kumar-type constitutive relationship meets the practical needs.展开更多
The finite element method(FEM)is used for simulation of the tube piercing process in Mannesmann mill.The numerical model is described with taking into consideration thermal phenomena in metal during forming. The simul...The finite element method(FEM)is used for simulation of the tube piercing process in Mannesmann mill.The numerical model is described with taking into consideration thermal phenomena in metal during forming. The simulated results visualize dynamic distributions of mean stresses,temperature,velocity and shear stresses, especially inside the workpiece.On the basis of the basic parameters,the phenomenon in the piercing process is analyzed.The model is verified by comparing the values of calculated force parameters of the piercing process and those measured in laboratory conditions.展开更多
基金financial support from Chinese National Nature Science Fund(Project No.50271009and No.51071019)Wuxi Seamless Steel Tube Company,Ltdthe Vanadium International Technical Committee via the CSM
文摘The relationship between microstructures and mechanical properties of a medium carbon V-N microalloyed steel used for N80 seamless oil-well tubes of hot rolling non-quenched/tempered(non-Q and T)was investigated.The results have shown that volume percentages of upper bainite,modified bainite and ferrite have a decisive influence on impact energies of steel tubes.When the total volume percentage of bainite is larger than 5%,the impact energy of tubes can not satisfy with the industrial criteria.Moreover,if the total volume percentage of bainite is smaller than 5%,then the impact energy of steel tubes enhances with volume percentage of ferrite increasing.The final microstructures have closely relation with tube billet quality,controlled cooling temperature after tube rolling and cooling method after stretch-reduction-diameter.High quality of medium carbon V-N microalloyed steel for non-Q and T oil-well tubes can be produced through comprehensive control of microstructures and mechanical properties in sub-procedures,especially for tube billet quality and controlled cooling parameters.
基金Item Sponsored by Tianjin Natural Science Foundation of China(06YFJ MJC02200,11JCZDJC22600)
文摘Based on test data from the hot forge experiments on Gleeble 1500, a Kumar type constitutive equation for 33Mn2V steel is established. Applying this constitutive equation in commercial FEM software of MSC/SuperForm 2005, the piercing process of 33Mn2V steel in Mannesmann mill is then simulated. The modeling results visualized the dynamic evolution of equivalent stress, especially inside the workpieee. It is shown that the non-uniform distribu- tion of stress on the internal and external surface of the workpiece is a distinct characteristic of processing tube pierc- ing. The numerical model was verified by comparing the values of calculated force parameters of the piercing process with those measured in laboratory eonditions. And it shows that the Kumar-type constitutive relationship meets the practical needs.
基金the Tianjin Natural Science Foundation (Nos.06YFJMJC02200 and 11JCZDJC22600)Wuxi Steel Tube Factory for its financial support
文摘The finite element method(FEM)is used for simulation of the tube piercing process in Mannesmann mill.The numerical model is described with taking into consideration thermal phenomena in metal during forming. The simulated results visualize dynamic distributions of mean stresses,temperature,velocity and shear stresses, especially inside the workpiece.On the basis of the basic parameters,the phenomenon in the piercing process is analyzed.The model is verified by comparing the values of calculated force parameters of the piercing process and those measured in laboratory conditions.
