| The development and progress of metal manufacturing promote the development of the corresponding processing. But the limited resources of metal forming process, manufacturing, use process are put forward higher requirements. So the metal formability has become scholars research emphasis of the designer. Environmental degradation, lightweight make sheet metal more graced is put forward. Performance of sheet metal forming research appears more important.This paper summarizes the methods of sheet metal forming and the current status also studying the development of the basic properties and group structure of the material studying the basic properties of the material and the group organization structure. Through tensile test we got the parameter of the mechanical properties 304 stainless steel and duplex steel DP780 s. Tensile experiment found that 304 stainless steel will appear slightly necking phenomenon in the process of tensile experiments, The result is that the tensile strength of 304 stainless steel is 722 MPa, unconstrained strength is 307.6MPa, 208.95 HRChardness, experiment the most vigorously for 14996.13 N; The tensile strength of dual phase steel DP780 912.9 MPa, unconstrained strength 753.1MPa, hardness of 120.57 HRC, the experiment is the most energetically is 18260.4 N. Analysis the results found that 304 stainless steel without appearance necking phenomenon in the process of fracture. Instead of the port relatively flat, this suggests that the dual phase steel DP780 brittleness is bigger. And the slight necking of the 304 stainless steel contains a high plasticity, ductility characteristic.Respectively the two experimental methods were studied conducting on modified Komatsu private servers press and cupping testing machine to cup drawing bulging experiment of ST12. These two methods are carried out using ST12 cup drawing experiment. One is the use of traditional cupping testing machine for experiment determine the cup drawing of ST12 value; Another kind is to Komatsu servo press to be modified, the modified Komatsu servo presses installed standard cup drawing die set is tested. Compare the experimental results of two kinds of experimental find that Komatsu servo press has been applied to the determination of the experimental cup drawing value smaller than traditional cup drawing machine of cup drawing value;moreover,it can be accurately measured points after trees, which is 100 times higher than the traditional precision in the cup drawing. Ultimately utilized modified Komatsu servo press Cupping experiments conducted within experimental error allowable range is feasible.The experiment making use of the modified Komatsu servo press for 304 stainless steel and duplex steel DP780, in which the research is under punch velocity. Analysis of the experimental data found that same material between different cup drawing stamping speed value is different. According to the cupping test value E r size, the influence of the speed on the experimental result was studied. Through comparing the size of the cup drawing E r of DP780 and 304 stainless steel, the size of 304 is from 9.3872 mm to 8.5934 mmwhile 780 is displeased from 7.5348 mm to7.380 mm. It is determined the effects of press speed on material formability. Range from 3 mm/s to 30mm/s, with the speed increase up while drawing value decreases. In the section of velocity from 3mm/s to 30mm/s,the Erishan value continuously drops as t he velocity rises,and the material’s anti-fracture shaping property gradually reduces. At last we can summarize that material’s bulge ability drops as the velocity increases. Compared 304 stainless steel with dual phase steel DP780, found that under the same speed of 304 stainless steel cup drawing experiment values bigger than dual phase steel DP780 cup drawing experiment values. After the experiment, we find that 304 stainless steel and dual phase steel DP780 exist differences between on fracture position. 304 stainless steel that the broken position of the rupture is in the side of the convex hull along the radial, and dual phase steel DP780 is the convex hull of the low end of the contact with the ball head punch first appears on the location of the point of transverse crack.The development of computer promotes the application of simulation software. Numerical simulation of the material bulging experiments to simulate the process to get the same results with the experimental results forming. Normative experimental verified process, the correctness of the results of treatment. With the ability to process simulation software experiments clearly show that is easier to identify deficiencies in front of them. Easy formability of metals and experimental is normative verify process. Result is correct.Load curve analysis is the classification and handling of the experimental results. We collate and analyze load curve by Cupping by displacement experiments recorded, We Got any instantaneous with ball head punch stress on the contact of the sheet- cup drawing the relation between the experimental value, Stress obtained with any instantaneous punch ball contact sheet on- cupping Found relation, and made according to the experimental results of graph. |
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