The influence of galvannealing on the transformation of the sink-roll groove-mark defect was studied by comparing the defects on galvannealed( GA) coating with those on galvanized( GI) coating. It was found that defec...The influence of galvannealing on the transformation of the sink-roll groove-mark defect was studied by comparing the defects on galvannealed( GA) coating with those on galvanized( GI) coating. It was found that defects on GI coating contained high amounts of aluminum,zinc dross,and a zinc-iron intermetallic outburst structure,as well as slight scratches on the substrate. After being galvannealed,the aluminum content was higher and there was a much greater outburst structure,which made the coating of the defect thicker than the normal coating,while the zinc dross and scratches on the substrate had disappeared due to zinc and iron diffusion during the galvannealing process.展开更多
A FEM model for a failed industrial example of roll forging was established to analyze the generation mechanisms of the mismatch of size and shape of two spring board.To demonstrate the formulation of these defects,th...A FEM model for a failed industrial example of roll forging was established to analyze the generation mechanisms of the mismatch of size and shape of two spring board.To demonstrate the formulation of these defects,the bites condition and contact status between rectangular groove and workpiece during rolling the first and second spring boards were analyzed.Then,a new oval-diamond groove combining oval groove and diamond groove was presented to eliminate these defects.By analyzing field variables under the same deformation degree,the larger friction can be obtained on the contact surface of workpiece and the oval-diamond groove.The physical experiment validates that the oval-diamond groove can eliminate these defects effectively,and the size of part is in good agreement with design requirement.展开更多
Cu–Nb microcomposite wire was successfully prepared by a groove rolling process.The effects of groove rolling on the diffraction peaks,microstructure,and properties of the Cu–Nb microcomposite were investigated and ...Cu–Nb microcomposite wire was successfully prepared by a groove rolling process.The effects of groove rolling on the diffraction peaks,microstructure,and properties of the Cu–Nb microcomposite were investigated and the microstructure evolutions and strengthening mechanism were discussed.The tensile strength of the Cu–Nb microcomposite wire with a diameter of 2.02 mm was greater than 1 GPa,and its conductivity reached 68%of the International Annealed Copper Standard,demonstrating the Cu–Nb microcomposite wire with high tensile strength and high conductivity after groove rolling.The results show that an appropriate groove rolling method can improve the performance of the Cu–Nb microcomposite wire.展开更多
Roll-stamping technology,a new process with both roll-forming and stamping characteristics,is suitable for manufacturing ultra-high-strength beam parts,especially variable cross-section beam parts.The rib groove is a ...Roll-stamping technology,a new process with both roll-forming and stamping characteristics,is suitable for manufacturing ultra-high-strength beam parts,especially variable cross-section beam parts.The rib groove is a local shape often used in automotive parts for positioning,avoidance,and stiffness strengthening on longitudinal and stiffening beams.In this study,two typical rib grooves,the flat-and round-bottom rib grooves,were selected to investigate the characteristics of the roll-stamping process of rib grooves.Using the ABAQUS software platform,a simulation analysis model of rib-groove roll stamping was established and different size rib grooves produced by the roll-stamping process were compared and analyzed.The results show that when the fillet radius of the rib groove increases,the maximum Mises stress,the maximum strain,and the maximum thinning rate decrease.For roll stamping,the minimum safe fillet radii of the two types of rib grooves are 8 and 4 mm,respectively.展开更多
Rolling torque for a seventeen passes, 125 x 125 mm HC SS316 billets rolled to a 16 mm diameter rod have been simulated. Torque calculations based on pressure exerted by the metal on the rolls and the area of contact ...Rolling torque for a seventeen passes, 125 x 125 mm HC SS316 billets rolled to a 16 mm diameter rod have been simulated. Torque calculations based on pressure exerted by the metal on the rolls and the area of contact during longitudinal rolling were obtained using the temperature values derived using the “Phantom Roll” method. Investigations were carried out for four different starting mean rolling temperatures between 988℃ and 1191℃ and at four different strain rates of 0.4s-1, 0.8s-1, 1.2 s-1 and 1.6s-1. Results obtained showed that for all cases, rolling in grooved rolls required higher torque compared to rolling in flat rolls. In general, it was observed that torque value increased as starting temperature decreases and for each set of starting temperatures, the torque value increases with temperature. In all cases, the torque values for grooved rolls were higher than those for flat rolls. This was due to the higher frictional effect, occasioned by the larger contact area between roll and stock. Results obtained also revealed an inverse relationship between strain rate and torque.展开更多
文摘The influence of galvannealing on the transformation of the sink-roll groove-mark defect was studied by comparing the defects on galvannealed( GA) coating with those on galvanized( GI) coating. It was found that defects on GI coating contained high amounts of aluminum,zinc dross,and a zinc-iron intermetallic outburst structure,as well as slight scratches on the substrate. After being galvannealed,the aluminum content was higher and there was a much greater outburst structure,which made the coating of the defect thicker than the normal coating,while the zinc dross and scratches on the substrate had disappeared due to zinc and iron diffusion during the galvannealing process.
基金Project(51275543)supported by the National Natural Science Foundation of ChinaProject(cstc2009aa3012-1)supported by the Key Program of Chongqing Science and Technology Foundation,China
文摘A FEM model for a failed industrial example of roll forging was established to analyze the generation mechanisms of the mismatch of size and shape of two spring board.To demonstrate the formulation of these defects,the bites condition and contact status between rectangular groove and workpiece during rolling the first and second spring boards were analyzed.Then,a new oval-diamond groove combining oval groove and diamond groove was presented to eliminate these defects.By analyzing field variables under the same deformation degree,the larger friction can be obtained on the contact surface of workpiece and the oval-diamond groove.The physical experiment validates that the oval-diamond groove can eliminate these defects effectively,and the size of part is in good agreement with design requirement.
基金This work was financially supported by the National Key R&D Program of China(No.2016YFA0401701)the National Natural Science Foundation of China(No.51601151).
文摘Cu–Nb microcomposite wire was successfully prepared by a groove rolling process.The effects of groove rolling on the diffraction peaks,microstructure,and properties of the Cu–Nb microcomposite were investigated and the microstructure evolutions and strengthening mechanism were discussed.The tensile strength of the Cu–Nb microcomposite wire with a diameter of 2.02 mm was greater than 1 GPa,and its conductivity reached 68%of the International Annealed Copper Standard,demonstrating the Cu–Nb microcomposite wire with high tensile strength and high conductivity after groove rolling.The results show that an appropriate groove rolling method can improve the performance of the Cu–Nb microcomposite wire.
基金National Key R&D Program Funding Project(No.2017YFB0304404).
文摘Roll-stamping technology,a new process with both roll-forming and stamping characteristics,is suitable for manufacturing ultra-high-strength beam parts,especially variable cross-section beam parts.The rib groove is a local shape often used in automotive parts for positioning,avoidance,and stiffness strengthening on longitudinal and stiffening beams.In this study,two typical rib grooves,the flat-and round-bottom rib grooves,were selected to investigate the characteristics of the roll-stamping process of rib grooves.Using the ABAQUS software platform,a simulation analysis model of rib-groove roll stamping was established and different size rib grooves produced by the roll-stamping process were compared and analyzed.The results show that when the fillet radius of the rib groove increases,the maximum Mises stress,the maximum strain,and the maximum thinning rate decrease.For roll stamping,the minimum safe fillet radii of the two types of rib grooves are 8 and 4 mm,respectively.
文摘Rolling torque for a seventeen passes, 125 x 125 mm HC SS316 billets rolled to a 16 mm diameter rod have been simulated. Torque calculations based on pressure exerted by the metal on the rolls and the area of contact during longitudinal rolling were obtained using the temperature values derived using the “Phantom Roll” method. Investigations were carried out for four different starting mean rolling temperatures between 988℃ and 1191℃ and at four different strain rates of 0.4s-1, 0.8s-1, 1.2 s-1 and 1.6s-1. Results obtained showed that for all cases, rolling in grooved rolls required higher torque compared to rolling in flat rolls. In general, it was observed that torque value increased as starting temperature decreases and for each set of starting temperatures, the torque value increases with temperature. In all cases, the torque values for grooved rolls were higher than those for flat rolls. This was due to the higher frictional effect, occasioned by the larger contact area between roll and stock. Results obtained also revealed an inverse relationship between strain rate and torque.
