Hollow parts of high accuracy and high strength can be produced by forming methods using liquid media. Hydroforming of tubes has reached a high standard for small parts (volume some 1000 cm3) and is further developed ...Hollow parts of high accuracy and high strength can be produced by forming methods using liquid media. Hydroforming of tubes has reached a high standard for small parts (volume some 1000 cm3) and is further developed for larger parts (volume some 10.000 cm3). Processes for hydraulic sheet metal forming are sometimes used for small parts from single sheets These pro-cesses are currently under intensive investigation, which is also true for the processing of double layered sheets Single sheets can be formed using membranes which separate the workpiece and the liquid. This results in interesting possibilities for a part and process integration in one step The forming performance of aluminum alloys can be enhanced by using a heated liquid media when forming without membranes.展开更多
Magnetically impelled arc butt welder is mainly used in the automotive industry for butt welding tubes.To extend the range of the welding applications,a new type of magnetically impelled arc butt welder for tube to pl...Magnetically impelled arc butt welder is mainly used in the automotive industry for butt welding tubes.To extend the range of the welding applications,a new type of magnetically impelled arc butt welder for tube to plate welding had been developed.The welder consisted two parts of mechanical device and electrical control system,in which the mechanical device with an appropriate clamping,location and upsetting control was specially designed for simple operation.The electrical control system involved the power supply,magnetic field and logic control of the welding.So the starting and rotating behaviour of the arc in the welding region of tube and sheet can be accurately controlled for the quality of tube to sheet joints.As a result,the welder for tube to sheet welding could generate a stable rotating arc by adjusting the welding parameters,and had a constant high-quality joint.展开更多
Based on the beam wave synchronous interaction in transverse and longitudinal directions at the same time and starting from Maxwell’s equation and linear Vlasov equation, the beam–wave interaction ‘hot’ dispersion...Based on the beam wave synchronous interaction in transverse and longitudinal directions at the same time and starting from Maxwell’s equation and linear Vlasov equation, the beam–wave interaction ‘hot’ dispersion equation considering both cyclotron resonance and Cherenkov resonance in a staggered double metallic grating traveling wave tube is deduced.Through the reasonable selection for geometric and electrical parameters, the numerical calculation and analysis of the ‘hot’ dispersion equation shows that the beam–wave interaction gain and frequency band with the cyclotron resonance enhancement effect are higher than those with only Cherenkov resonance radiation.展开更多
基金The author gratefu1ly acknowledges Dipl.-Ing.R.Breede and Dipl.-Ing.T.Prange for the preparation ofthe results.
文摘Hollow parts of high accuracy and high strength can be produced by forming methods using liquid media. Hydroforming of tubes has reached a high standard for small parts (volume some 1000 cm3) and is further developed for larger parts (volume some 10.000 cm3). Processes for hydraulic sheet metal forming are sometimes used for small parts from single sheets These pro-cesses are currently under intensive investigation, which is also true for the processing of double layered sheets Single sheets can be formed using membranes which separate the workpiece and the liquid. This results in interesting possibilities for a part and process integration in one step The forming performance of aluminum alloys can be enhanced by using a heated liquid media when forming without membranes.
基金Item Sponsored by National Natural Science Foundation of China(51101050)Natural Science Foundation of Jiangsu Province of China(BK2011257)
文摘Magnetically impelled arc butt welder is mainly used in the automotive industry for butt welding tubes.To extend the range of the welding applications,a new type of magnetically impelled arc butt welder for tube to plate welding had been developed.The welder consisted two parts of mechanical device and electrical control system,in which the mechanical device with an appropriate clamping,location and upsetting control was specially designed for simple operation.The electrical control system involved the power supply,magnetic field and logic control of the welding.So the starting and rotating behaviour of the arc in the welding region of tube and sheet can be accurately controlled for the quality of tube to sheet joints.As a result,the welder for tube to sheet welding could generate a stable rotating arc by adjusting the welding parameters,and had a constant high-quality joint.
基金supported by National Natural Science Foundation of China(No.61671431)
文摘Based on the beam wave synchronous interaction in transverse and longitudinal directions at the same time and starting from Maxwell’s equation and linear Vlasov equation, the beam–wave interaction ‘hot’ dispersion equation considering both cyclotron resonance and Cherenkov resonance in a staggered double metallic grating traveling wave tube is deduced.Through the reasonable selection for geometric and electrical parameters, the numerical calculation and analysis of the ‘hot’ dispersion equation shows that the beam–wave interaction gain and frequency band with the cyclotron resonance enhancement effect are higher than those with only Cherenkov resonance radiation.
