The necessary condition of pure rolling for the rollers moving along its individual cams are obtained by the analysis of the loading status of the rollers and it provides a theoretical basis for adjustment of rolling ...The necessary condition of pure rolling for the rollers moving along its individual cams are obtained by the analysis of the loading status of the rollers and it provides a theoretical basis for adjustment of rolling stand.展开更多
The microstructures and interracial characteristics of matrices at the inwalls and the out-walls of the cold-rolled tube with different amounts of deformation were investigated by the scanning electronic microscope （...The microstructures and interracial characteristics of matrices at the inwalls and the out-walls of the cold-rolled tube with different amounts of deformation were investigated by the scanning electronic microscope （SEM）, the optical microscope （OM）, and the transmission electronic microscope （TEM） techniques. It was observed that as the amount of deformation increases, the flaws nucleate at the out-walls of the cold rolled tube, the stress-induced martensites change from （111 ） type Ⅰ twins to （011） type Ⅱ twins and then to （100） compound twins, nanocrystals and bulk amorphisation happen, the high density dislocation causes stress concentration at the out-walls of the Ti50Ni50 cold-rolled tube, and then precipitates its fracture, and the Ti2Ni particles strengthen the grain boundaries and curb the dislocation movements during plastic deformation. The inhomogeneity level of the grains in the Ti50Ni50 alloy plays an important role on the fracture of the Ti50Ni50 cold rolled tube.展开更多
Based on the deformation characteristics of Y-type mill,a finite element model for simulating the formation process of shaped steel tube for driving shaft is proposed.The distributions of stress and strain were obtain...Based on the deformation characteristics of Y-type mill,a finite element model for simulating the formation process of shaped steel tube for driving shaft is proposed.The distributions of stress and strain were obtained from the simulation.The outer diameter and transverse wall thickness were also analyzed quantitatively.Experiment was done on Y-type mill.A comparison between simulation results and experiment results shows that the simulated results of shaped steel tube are in good agreement with the on-site data.The model could provide the basis for theoretical research and engineering applications of shaped steel tube rolling process.展开更多
A new model,called object model,for the simulation of cold roll-forming of tubes is presented.The model inherits the advantages of old models and is the embodiment of forming process that the strip is rolled step by s...A new model,called object model,for the simulation of cold roll-forming of tubes is presented.The model inherits the advantages of old models and is the embodiment of forming process that the strip is rolled step by step from feed rollers to last rolling pass.The elastic-plastic large deformation spline finite strip method based on updated Lagrangian method has been developed by improving the stiffness and transition matrix.Combined theory formulas and new analytical model,the forming process of a tube has been simulated successfully as an example.The analytical results are submitted and indicate that the proposed simulation method and new model are applicable.展开更多
基于设计的轧辊孔型,使用三维有限元分析软件Simufact,对28Ni Cr Mo V8.5钢管典型规格准16 mm×1.5mm皮尔格冷轧过程进行了数值模拟。研究了不同摩擦系数及孔型开口系数对冷轧管横向壁厚分布及精度的影响规律。结果表明:钢管的横向...基于设计的轧辊孔型,使用三维有限元分析软件Simufact,对28Ni Cr Mo V8.5钢管典型规格准16 mm×1.5mm皮尔格冷轧过程进行了数值模拟。研究了不同摩擦系数及孔型开口系数对冷轧管横向壁厚分布及精度的影响规律。结果表明:钢管的横向壁厚分布是不均匀的,在孔型开口及孔顶处出现最小值,在孔型侧壁角45°两侧出现最大值。随着摩擦系数和孔型开口系数增大,不均匀的横向壁厚变得更加严重。当轧辊与轧件的摩擦系数由0.080增大到0.095时,冷轧管的横向壁厚精度由5.51%变到6.98%;当孔型开口系数由0.051增大到0.061时,横向壁厚精度由5.51%变到8.11%。展开更多
文摘The necessary condition of pure rolling for the rollers moving along its individual cams are obtained by the analysis of the loading status of the rollers and it provides a theoretical basis for adjustment of rolling stand.
文摘The microstructures and interracial characteristics of matrices at the inwalls and the out-walls of the cold-rolled tube with different amounts of deformation were investigated by the scanning electronic microscope （SEM）, the optical microscope （OM）, and the transmission electronic microscope （TEM） techniques. It was observed that as the amount of deformation increases, the flaws nucleate at the out-walls of the cold rolled tube, the stress-induced martensites change from （111 ） type Ⅰ twins to （011） type Ⅱ twins and then to （100） compound twins, nanocrystals and bulk amorphisation happen, the high density dislocation causes stress concentration at the out-walls of the Ti50Ni50 cold-rolled tube, and then precipitates its fracture, and the Ti2Ni particles strengthen the grain boundaries and curb the dislocation movements during plastic deformation. The inhomogeneity level of the grains in the Ti50Ni50 alloy plays an important role on the fracture of the Ti50Ni50 cold rolled tube.
文摘Based on the deformation characteristics of Y-type mill,a finite element model for simulating the formation process of shaped steel tube for driving shaft is proposed.The distributions of stress and strain were obtained from the simulation.The outer diameter and transverse wall thickness were also analyzed quantitatively.Experiment was done on Y-type mill.A comparison between simulation results and experiment results shows that the simulated results of shaped steel tube are in good agreement with the on-site data.The model could provide the basis for theoretical research and engineering applications of shaped steel tube rolling process.
基金the National Natural Science Foundation of China (No. 50375135)the Talent Foundation of Beijing Jiaotong University (No. 2003RC059)
文摘A new model,called object model,for the simulation of cold roll-forming of tubes is presented.The model inherits the advantages of old models and is the embodiment of forming process that the strip is rolled step by step from feed rollers to last rolling pass.The elastic-plastic large deformation spline finite strip method based on updated Lagrangian method has been developed by improving the stiffness and transition matrix.Combined theory formulas and new analytical model,the forming process of a tube has been simulated successfully as an example.The analytical results are submitted and indicate that the proposed simulation method and new model are applicable.
文摘基于设计的轧辊孔型,使用三维有限元分析软件Simufact,对28Ni Cr Mo V8.5钢管典型规格准16 mm×1.5mm皮尔格冷轧过程进行了数值模拟。研究了不同摩擦系数及孔型开口系数对冷轧管横向壁厚分布及精度的影响规律。结果表明:钢管的横向壁厚分布是不均匀的,在孔型开口及孔顶处出现最小值,在孔型侧壁角45°两侧出现最大值。随着摩擦系数和孔型开口系数增大,不均匀的横向壁厚变得更加严重。当轧辊与轧件的摩擦系数由0.080增大到0.095时,冷轧管的横向壁厚精度由5.51%变到6.98%;当孔型开口系数由0.051增大到0.061时,横向壁厚精度由5.51%变到8.11%。
