Advanced Materials Research Vols. 97-101

Abstract: The cladding steel plate was successfully produced using vacuum cladding rolling method. In cladding steel plate, cladding interface vanished and was replaced new recrystallized grains, and no interface defects or inclusions were detected. Z direction tensile testing indicated that tensile fracture occurred in basal materials, i.e. strength and contraction of cross area are those of basal materials. Furthermore, with decreasing vacuum level of electron beam welding, size and amount of interface inclusions would obviously increase.

Abstract: A new technology for manufacturing large sealing flange is presented. It involves bending combined with welding and finishing machining at the construction site. The innovation in this method is that the preliminary machining of the section, using a heavy-duty vertical lathe, is replaced by precision bending. Therefore large diameter flange can be manufactured at very low cost. Bending of a specimen with an E-cross-section was investigated by numerical simulation and experiment. The mechanism of lateral deformation was analyzed and the method to overcome it was given. This technology was successfully used for manufacturing a large flange which used in a large wind tunnel.

Abstract: A study was conducted by optical microscope (OM) and transmission electron microscope (TEM) on the microstructure evolution of TA15 alloy by severe plastic deformation (SPD) and annealing after SPD. In this study, equal channel angular pressing (ECAP) was taken as the method of SPD. The chief aim of the present work is to investigate the temperature effects of ECAP and annealing after ECAP on microstructure of TA15 alloy. The results indicate that equiaxed microstructure has been obtained by ECAP at the temperatures of α+β phase region, and that with the increase in pressing temperature, equiaxed grains have become coarser and the content of α phase has reduced. β grains have been coarsened severely since the pressing temperature was above the α-β transformation temperature (Tβ). Annealed at proper temperature after ECAP, the α phase of TA15 alloy has been more homogeneous, prior α phase has been well globularized, and grains have not grown obviously. According to the testing of TA15 alloy, the optimized temperature parameters of ECAP and annealing after ECAP are 900°C and 700°C. Observation and Analysis of the TEM morphological images illustrate that a quantity of twinning deformations have been produced by ECAP at the temperatures below Tβ, which leads to the continued plastic deformation through the restarting of many slip bands.

Abstract: Roll-over of crank arm is the major defect of forming quality during the upsetting process. Bending and upsetting forging of crankshaft was simulated by using the rigid-plastic finite element model. The theories of metal flowing and distribution of deformation during the bending and upsetting forging were analyzed, the root cause of the roll-over of crank was found; the optimal combination of the bending and upsetting velocities was obtained; the experimental results agree well with simulations.

Abstract: Flanging is a method of sheet metal forming process under combined compressive and tensile conditions using a punch and die to raise closed rims (flanges or collars) on pierced holes. For the flanging product used for the automotive steering part, the thickness of the bottom radius area is very important because of the crack usually occurred during the using process. But during conventional flanging process, the thickness of the rim and the bottom radius area were decreased seriously and make the hole flanging not strong enough to be used. In order to increase the thickness of bottom radius area of the flanging wall, a new method that combines flanging process and cold forging process was proposed in this paper and a special forming die set was designed with a stripper subjected to counter-pressure with an aim to obtain a more substantial flange. FEM software DEFORM 3D was employed to simulate these flanging part forming processes. The results showed the thickness of bottom radius area of the flanging wall was increased and a more substantial flange was obtained.

Abstract: In this paper, the yield condition of Hill’s orthotropic yield criterion under axial symmetric plane stress state was discussed. The yield function of orthotropic material was proposed and the analytical solution to meet the condition of equations of equilibrium and compatibility under axial symmetric plane stress state is obtained, in which the conditions of power hardening materials was considered. The research result indicates that hardening coefficient and anisotropic parameter have substantial influence over stress and strain. However, in the presence of the coefficient R90=H/F，the influence appears to be quite weak.

Abstract: TWB and its forming technology play important role in lightweight manufacturing for the automobile parts. The weld-line movement during TWB forming process affects the product quality greatly. In this paper, two main influence factors of the movement, BHF and the blank thickness at the both sides of the weld-line, were studied by both the experiments and finite element simulation. The results showed that BHF has significant impact on the weld-line movement, especially when the thickness difference of the blanks in TWB is beyond a certain range. Besides, suitable BHF and thickness of the blanks can not only control the weld-line movement, but also improve the formability of TWB.

Abstract: 7A09 aluminum alloy is served as an important structural material in many fields. In this paper, power spinning of semi-continuous casting 7A09 aluminum alloy tube blank was carried out, and the effects of process parameters, such as spinning temperature and roller feeding ratio, on spinnability were analyzed, further the mechanical property was tested on a tensile testing machine. The results show that: at 300°C and 1.2mm/r roller feeding ratio, semi-continuous casting 7A09 aluminum alloy tube blank has good spinnability; after spun, the yield strength is increased 44%, and elongation is increased 130%.

Abstract: The AZ31 magnesium alloy tube was used for electromagnetic forming experiment of three kinds of input voltages. The stress-strain state of tube forming was analyzed. It was shown that the cause of oblique crack of tube was of axial inhomogeneous distribution and , and the cause of longitudinal crack was and of inhomogeneous distribution in circumferential direction. Moreover, the electromagnetic field and force field during electromagnetic forming was simulated by ANSYS software. The experiment proved the simulation result.

Abstract: A model of side pattern CAD/CAM on mould for auto lamp integrated with CATIA V5 is built. After analyzing the properties of design and the manufacture of side pattern on mould for auto lamp, key technology, such as grouping, sorting, determination of continuity, fairing and fitting of side pattern curves, generating of NC files and G codes, are presented. Using out-process redeveloping tools of CATIA V5, a CATIA V5 integrated side pattern CAD/CAM system for mould of auto lamp is developed. At last, a practical example shows that the technology and the software satisfy the design and manufacture of side pattern on mould for auto lamp. The technology and the software have been used in related enterprise successfully.