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161.
Application of electromagnetic-assisted stamping (EMAS) technique in incremental sheet metal forming 总被引:1,自引:0,他引:1
C.N. Okoye J.H. Jiang Z.D. Hu 《International Journal of Machine Tools and Manufacture》2006,46(11):1248-1252
The application of high velocity electromagnetic-assisted stamping (EMAS) technique in incremental sheet metal forming has been proposed. EMAS whose principle is based on Lorenz force is a hybrid forming process that uses both quasi-static conventional stamping technique and electromagnetic forming actuators built into sharp corners and other difficult-to-form contours to form metals. The recent push to use more artificial intelligent (AI) aluminum alloys in automobile and aircraft industries as a result of increasing demand for fuel efficient cars and aircrafts, large size vehicle panels, improved formability limit of materials and weight reduction have placed EMAS as one of the best high velocity forming technique.It is believed that the end result of this vision will lead to more cost effective land and aerospace vehicles. 相似文献
162.
163.
Jong Hyun Suh To Hoon Kim Byung Kil Yu Kyoung Don Lee 《Metals and Materials International》1998,4(2):157-163
Research was conducted on tailored blank welding between mild steel sheet and Zn-coated steel sheet using CO2 laser beam. The materials used in this study were low carbon steel sheets with a thickness of 1.2 mm and Zn-coated steel
sheet with the same thickness and 6.3 μm Zn coating. Experiments were conducted by applying the Taguchi method to obtain optimum
conditions for the application of this tailored blank laser welding method in practical manufacturing processes. Optical microscopy,
XRD, SEM and TEM analysis were performed to observe the microstructures and to determine the structures of welded zone. In
addition, mechanical properties were measured by the microhardness test, tensile test and Erichsen test to evaluate the formability
of the welded specimen. There was no trapped Zn in the fusion zone, and the phases of this region consisted of polygonal ferrite,
quasi-polygonal ferrite, banitic ferrite and martensite. The elongation value of welded specimen was more than 80% of the
value in substrate metal, and the LDH value was more than 90% of the value in substrate metal. 相似文献
164.
板料弯曲回弹的有限元模拟影响因素研究 总被引:3,自引:1,他引:3
阐述了板料成形数值模拟中回弹问题的研究历史和发展现状,分析了塑性弯曲加工中工件发生弯曲回弹的原因、特点及有限元模拟过程的影响因素,总结了回弹模拟的算法,从成形过程模拟和回弹计算两方面系统分析了影响回弹模拟准确性和收敛性的主要因素及改进方向,讨论了模具设计中回弹的补偿算法 ,并提出了当前控制回弹的基本方法 相似文献
165.
An investigation on the hot extrusion process of magnesium alloy sheet 总被引:11,自引:0,他引:11
This study investigates the hot extrusion of magnesium alloy sheets at various temperatures, material, speed and lubricant. A multi-speed method is applied to extrude a magnesium alloy sheet at a high extrusion ratio. The experimental results are analyzed to optimize the processing conditions, increase the tensile strength and reduce the extrusion load on the magnesium alloy thin sheet. Nowadays, most magnesium alloy products are manufactured by industrial die casting. Hot extrusion is seldom used to finish magnesium products because the extrusion speed, temperature and extrusion load significantly effect the properties of the product. In this study, the Taguchi experimental method with the orthogonal array is applied. ANOVA is used to investigate how parameters affect the extrusion process. All possible mechanical properties of the product are analyzed to obtain the optimal process parameters. In addition, magnesium alloys with different compositions are experimentally tested to determine the mechanical properties of the extruded product and obtain the relationship between the process parameters and the properties of the material. 相似文献
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169.
Cold-rolled and annealed ultra-high strength sheet steels with good ductility accompanied by TRIP of retained austenite have
received considerable attention in recent years. This paper discusses the effect of silicon content and annealing temperature
on the formation of retained austenite and the mechanical properties in Fe-0.34%C-1.7% Mn steels whose structure consists
of ferrite, bainite and retained austenite. Silicon inhibited the cementite formation in bainite during isothermal holding
and partitioned carbon from bainite to austenite, resulting in an increase in retained austenite content. When the silicon
content was increased to 1.0 wt.% or higher, the amount of retained austenite markedly increased leading to good mechanical
properties. 0.34%C-1.03%Si-1.7%Mn steel showed a high tensile strength of 1,030 MPa and a total elongation of 34.5% when annealed
at 780°C for 5 min followed by isothermal holding at 400°C for 5 min. In this case, the amount of retained austenite was about
25%. The variation in tensile strength-elongation combination had good correlation with that in the amount of retained austenite
with both annealing temperature and silicon content. The most retained austenite was obtained in the steel annealed at just
above AC1 temperature. The annealing temperature which gives the most retained austenite was decreased with decreasing the silicon
content. 相似文献
170.