Variable Contact Pressure and Variable Drawbead Height Influence on Deep Drawing of Al Alloys Sheets
The process of deep drawing is influenced by many factors. During the forming process, only two of those factors can be controlled. They are blank holding force and drawbead height. Realisation of such control requires relatively complex computerized apparatus. For this experimental research, electro-hydraulic sheet-metal strip sliding device has been constructed. Basic capacity of realized device is obtaining contact pressure and drawbead height as functions of time or stripe displacement. Additional features consist of the ability to measure drawing force, contact pressure, drawbead displacement etc. Presented in the paper are the results of influencing of increasing and decreasing drawbead height functions in combination with increasingdecreasing function of contact pressure. Stripe material is aluminium alloy AlMg4,5Mn0,7 sheet metal. Contact condition are additionally influenced by application of mineral oil or completely dry tool and stripe surfaces. Drawbead geometry, with rounding radii of 2 and 5 mm, is also varied. The accomplished results indicate that simultaneous effects of variable drawbead height, variable contact pressure, tool geometry and appropriate friction conditions can influence the plastic flow process in line with desired change of forming force.
Effect of spring-back and spring-forward in V-die bending of St1403 sheet metal plates
Today there is widespread usageof high strength steels (HSS), and ultra high strength steels in the manufacturing industry. Especially in the automobile industry for the rigid and light weight chassis components made out of high strength steels. During sheet metal forming material undergoes plastic deformations and after the process of forming and taking out of the tool, formed sheet metal plate try to take previous position and elastically deforms. This deformation is called elastic spring-back. Special version of this elastically unloading is called spring forward. It can be seen in V-die bending with small punch radius, and small punch angle which is shown in this paper.
Magnetic properties of Lu2Fe17 crystals
Abstract We present the results of crystal structure and magnetization studies of three single crystals grown from melts of different nominal compositions in the vicinity of the Lu2Fe17 stoichiometry. The ferromagnetic state of the crystals is strongly dependent on the real sample composition and the local atomic ordering. A drastic difference is observed in the behaviour of the ferro–antiferromagnetic transition, even in crystals for which almost identical composition and crystal parameters were determined by microprobe and X-ray analysis.