Applied Mechanics and Materials Vols. 217-219

Abstract: A neural network model is established to predict the joint quality in resistance microwelding (RMW) of fine Cu wire and stainless steel thin sheet. The preheat current, welding current, weld time and electrode force are selected as the input parameters and the tensile strength as the output parameter in the model. The prediction program is compiled in MATLAB through the detailed designing of hidden layer and the selection of the transfer function. The network performance is verified by experiment, and its accuracy meets the production requirements in the actual welding.

Abstract: Based on the motion relation between rollers and work piece during cross wedge rolling (CWR) process, roller profile equations for cam forming were studied. A three-dimensional entity model of the roller was established using the profile equations. Process of cam forming by CWR was simulated by DEFORM-3D. The FEM data was used to analyze dimensional accuracy of the formed cam. Results demonstrate that the equations can be used in roller design for cam rolling.

Abstract: Spiral boring tool is widely used in the manufacturing of the deep spiral groove. Based on the design of spiral boring structure, study on it by stress analysis and experiment, then get the change situation of force and torque in the given processing conditions, this provides a method basis for the study of spiral boring tool.

Abstract: For decreasing axial milling force in helical milling and improving machining quality, researches have been carried out on end mills’ geometrical parameters. And experiments have also been designed to analyze the effect of end mill’s axial cutting edge angle on axial milling force. The results indicate that when other mills’ geometrical and process parameters are constant, the generated mean axial milling force is remarkably decreased, following the axial cutting edge angle’s little increase. In addition, as the pitch of helical milling path increases, larger axial cutting edge angle leads to higher relative decrease ratio. And a qualitative analysis is also put up to point out the reason for the phenomena above, that is, part of the low-speed region of axial cutting edge quits milling. These conclusions could supply valuable references to reasonable choice of combinations of mills’ geometrical and process parameters in helical milling.

Abstract: By method of TIG, under certain welding craft conditions, two kinds of welding wire were added,1Cr18Ni9Ti and 2Cr13 steel were welded. By (ZEISS) OM, SEM, the microstructure of two kinds of 2Cr13 and 1Cr18Ni9Ti welding joints were observed and analyzed, by electronic universal tensile machine, mechanical properties of welding joints were measured. The results show that 2Cr13 and 1Cr18Ni9Ti welded joints is typical columnar crystal, the microstructure is lath martensite + residual austenite + carbide; the micro-hardness of two kinds of welding joint changes fluctuantly, it increases firstly and reduces secondly, the value is up to max in welded joint zone. The welding joints filled in two kinds of materials, tensile samples rupture forms are toughness rupture; plasticity and strength of welding joint filled in ER308 welding material is better than that of welding joint filled in H1Cr21Ni10Mn7Mo welding wire. On the contrary, its hardness is lower than that filled in H1Cr21Ni10Mn7Mo welding wire.

Abstract: Abstract. The change rules of the billet temperature field and extrusion load are the significant basis for the optimal design of the needle piercing extrusion process based on ingot billet for the manufacture of large-diameter thick-walled tube. Taking the needle piercing extrusion process of a 7075 aluminum alloy tube with sizes of Φ500mmx400mm/6000mm as study object, we developed a precise FE model for the process under DEFORM-2D environment, then numerically revealed the distributions and evolution rules of the billet temperature field, and obtained the effects of the extrusion speed and initial billet temperature on the billet temperature filed and extrusion load. The results show that the peak extrusion load decreases linearly with the increase of initial billet temperature but is insensitive to the extrusion speed, and that the peak temperature rises with the increase of the extrusion speed and initial billet temperature, and always locates on the surface of the initially extruded tube close to the exit of the cavity die.

Abstract: The stress field of compound cast rollers during centrifugal casting process was investigated in this work. A finite element (FE) model was built to simulate the internal stress fields during cooling process, in which phase transformation was considered. The mechanical parameters employed in stress numerical simulation were measured by using thermal/mechanical simulator. The residual internal stress of the compound cast roller by centrifugal casting method was measured by using X-ray stress analyzer. The simulated results are in agreement with the measured ones very well. According to this model, the temperature and stress fields of the compound cast roller during centrifugal casting process were simulated.

Abstract: Hydroforming is a new deforming technology , Many of numerical analyzes of bulge forming processes have concentrated exclusively on the behavior of the deforming tube . Finite element models have been developed to simulate stroke-controlled tube , with particular emphasis on the state of stress and deformation of the work piece in the paper . The effects of using internal pressure alone and combined internal pressure and axial compressive load were investigated and it was found that the development of the location of maximum strain was dependant on the type of loading used.

Abstract: Compression molding is the most important making method of bonded NdFeB magnets. Characteristics of bonded NdFeB magnets are analyzed. Based on test, research and lot production practice, the important effects of mould structure, press structure and compression molding actions on magnets’ quality are introduced, The key techniques that controlling the quality of bonded NdFeB magnets are summarized.

Abstract: The process of injection molding, packing and cooling for injection mold PET (Polyethylene terephthalate) cavity was analyzed and the cause of fatigue stress cracking was investigated. An analysis method of injection mold cavity fatigue based on Ansys Workbench(AWB)was put forward. A simulation of temperature field, displacement, thermal stress field and fatigue life for the cavity of a work cycle based on heat transfer theory was completed. Provide effective measures to avoid fatigue stress cracking and optimization design of the injection mold.