Applied Mechanics and Materials Vols. 217-219

Abstract: By establishing an axisymmetric finite element model of the electromagnetic riveting (EMR) joint, we studied the influence of riveting die angle on joint interference and the driven head. It was found that a decrease in the die angle leads to a decrease in the highest temprature in the adiabatic shearing band (ASB). An increase in interference and contact pressure between the rivet shank and apertue wall was also obeserved when decreasing the die angle, which has been proved to be benificial to the fatigue performance of the joint.

Abstract: The conventional hydroforming process for automobile axle housing needs a large-tonnage press and has the drawback of the dome part being apt to burst due to the large thinning. A new forming technology, bulging-pressing compound-deforming for automobile axle housing, is proposed, which is suitable for the large variable-diameter tube parts with special-shaped cross-sections. The initial tube is made into the axisymmetric peforming tube after the ends necked and the middle hydroformed, and which then is pressed into the axle housing sample by the dies. For a small automobile axle housing, the process tryout and the pressing dies were designed, and the axle housing samples were successfully produced with a common press. Compare with the conventional hydroforming process, the forming corner radiuses of present samples are smaller and the internal pressure decreased 60%. The results show that the process has the advantages of good corner-filling ability and low internal hydraulic pressure.

Abstract: Cutting heat and cutting temperature are the most important physical phenomena in cutting machining process. Cutting temperature and its distribution affect the abrasion of cutting tool and the operating life directly. Meanwhile they can affect the machining precision and the machined surface quality. In this paper the ABAQUS finite element software is used to predict the thermal distribution and variable condition, moreover it is tested through the experiment. As is shown from the result, the changing trend of cutting temperature by the simulation is consistent with the real measured result, which has better precision and reliability and supplies the theoretical basis for the deformation analysis caused by cutting heat in the cutting machining process.

Abstract: The electrochemical corrosion tests of SUS304 stainless steel joint which was welded by electrode arc welding show that. The welding energy has obviously effect upon corrosion resistance of welding joints. The welding current directly influences the corrosion resistance of heat affected zone (HAZ) of welding joint. The Surface of joints was remelted by the micro-plasma arc and argon arc process. It is suggested that corrosion resistance of welding joint was improved obviously after remelting. The main reasons for improving the corrosion resistance of welding joint may be that grain refined, chromium oxidation film formed and elements diffusion inhibited by arc-remelting process.

Abstract: Nanoindentation technique was employed to examine the nanohardness and elastic modulus of weld joints of 1000MPa Class high strength low alloy (HSLA) steel. The distribution of micro scales mechanical behavior was analyzed combined with microstructure observation by OM, SEM and TEM. It was shown that weld metal and base metal were mainly of bainite and their nanohardness is about 4.0GPa. In the heat affected zone, fine grained heat affected zone and coarse grained heat affected zone with lath martensite structure had the maximum hardness (above 4.75GPa). From inter critical region, the hardness of HAZ decreased to 2.5 GPa. However, the elastic modulus of metallic material is not much sensitive to the microstructure.

Abstract: The hot forging process of automobile engine crankshaft was simulated in the present study on the basis of the finite element software DEFORM-3D. The materials of die and crankshaft workpiece are H13 steel and L1438 steel, respectively. The material flow in the die, contact pressure distribution and temperature distribution of the die were investigated. The interaction forces between the workpiece and the dies were mapped onto die faces to serve as load boundary conditions for die stress analysis. The results showed that the die stress reduces with increasing temperature and increases with increasing strain rate. Such behavior is likely associated with flow stress of the workpiece, which reduces with increasing temperature and increases with increasing strain rate. High flow stress results in high die stresses and hence more easily leads to die failure.

Abstract: According to the color contour map of the 3D injection molding simulation results, the commonly used color contour map drawing algorithm was researched, and a three-dimensional color image rendering algorithm which based on the "physical field values and color range mapping" was given too. And the key technologies of the algorithm which was used to draw 3D color contour map were introduced in detail. In the end, an example was given.

Abstract: Presented here is the simulation of uniaxial stretch forming using two punches in a sheet metal forming operation. In the finite element modelling, the sheet metal strip was held by two bank holders and two punches are able to move in two directions to stretch the sheet metal. Due to the friction between the punch and sheet metal, it was found that friction affects the sheet metal forming quality, however by adopting an optimal punch path the effect of friction in sheet metal forming can be reduced. The effect of punch paths on the quality of the sheet metal are also reported in this paper.

Abstract: The effect of the position and shape of solid-liquid interface on process parameters has been studied by the numerical simulation method, and the reasonable process parameters have been given. The results shows that the position and shape of solid-liquid interface is mainly affected by mold temperature, casting speed and cooling distance. It were moved to the mold export with the improvement of the mold temperature, casting speed or the reduce of cooling capacity. And the reasonable process parameters are that the mold temperature is 1363-1373 K, casting speed is 80-100mm/min, cooling distance is 40-50mm. The research results would obtain stable operation conditions and improve the billet quality.

Abstract: Ranque-Hilsch Vortex Tube (RHVT) is a device with no moving parts and do not require electricity or chemicals to function. It has been used widely in cooling and heating of various operations, thermal test, dehumidification, gas liquefaction, ice production and mixture separation. Sustainable machining refers to the efforts to reduce the environmental impact of machining. The use of minimum quantity lubrication (MQL) is an effective solution for a more sustainable machining process. In this paper we propose the use of RHVT in MQL. The structure, working principles and types of RHVT are presented in this paper. Parameters associated with RHVT and the various possible working fluids are discussed in brief.