Microstructure and mechanical properties of A356 aluminum alloy wheels prepared by thixo-forging combined with a low superheat casting process

The A356 aluminum alloy wheels were prepared by thixo-forging combined with a low superheat casting process. The as-cast microstructure, microstructure evolution during reheating and the mechanical properties of the thixo-forged A356 aluminum alloy wheels were investigated. The results show that the A356 aluminum alloy billet with fine, uniform and non-dendritic grains can be obtained when the melt is cast at 635 ℃. When the billet is reheated at 600 ℃ for 60 min, the non-dendritic grains are changed into spherical ones and the billet can be easily thixo-forged into wheels. The tensile strength and elongation of thixo-forged wheels with T6 heat treatment are 327.6 MPa and 7.8%, respectively, which are higher than those of a cast wheel. It is suggested that the thixo-forging combined with the low superheat casting process is an effective technique to produce aluminum alloy wheels with high mechanical properties.

Production of A356 aluminum alloy wheels by thixo-forging combined with a low superheat casting process

The A356 aluminum alloy wheels were produced by thixo-forging combined with a low superheat casting process. The as-cast microstructure, microstructure evolution during reheating and the mechanical properties of thixo-forged wheels made from the A356 aluminum alloy were studied. The results show that the A356 aluminum alloy round billet with fine, uniform and non-dendritic grains can be obtained when the melt is cast at 635 ℃ When the round billet is reheated at 600 ℃ for 60 min, the non-dendritic grains are changed into spherical ones and the round billet can be easily thixo-forged into wheels. The tensile strength, yield strength and elongation of the thixo-forged wheels with T6 heat treatment are 327.6 MPa, 228.3 MPa and 7.8%, respectively, which are higher than those of a cast wheel. It is suggested that the thixo-forging combined with the low superheat casting process is an effective technique to produce aluminum alloy wheels with high mechanical properties.

Segregation in squeeze casting 6061 aluminum alloy wheel spokes and its formation mechanism

Segregation can seriously damage the mechanical properties of the aluminum alloys.6061 aluminum alloy wheel spokes were prepared by squeeze casting.To investigate the formation mechanism of segregation,the microstructure of the alloy was observed using scanning electron microscopy,energy dispersive spectrometry,X-ray diffraction and electron microprobe analysis methods.The Gibbs energy of each phase during solidification was calculated by JMat Pro.Results show that the segregation phases in the R-joint of the wheel spokes are mainly composed of Mg_(2)Si,β-Al Fe Si and Al_(5)Cu_(2)Mg_(8)Si_(6)intermetallics.During the solidification of the 6061 aluminum alloy wheels,Mg_(2)Si andα-Al Fe Si phases precipitate in the mushy zone at first.With the decrease of temperature,α-Al Fe Si transforms intoβ-Al Fe Si,while Al_(5)Cu_(2)Mg_(8)Si_(6)precipitates from the solid-state aluminum alloy after solidification.Segregation at the R-joint of wheel spokes is mainly caused by insufficient cooling,so the cooling during alloy solidification should be enhanced to avoid segregation.

Numerical simulation of low pressure die-casting aluminum wheel

The FDM numerical simulation software,ViewCast system,was employed to simulate the low pressure die casting(LPDC)of an aluminum wheel.By analyzing the mold-filling and solidification stage of the LPDC process,the distribution of liquid fraction,temperature field and solidification pattern of castings were studied.The potential shrinkage defects were predicted to be formed at the rim/spoke junctions,which is in consistence with the X-ray detection result.The distribution pattern of the defects has also been studied.A solution towards reducing such defects has been presented.The cooling capacity of the mold was improved by installing water pipes both in the side mold and the top mold.Analysis on the shrinkage defects under forced cooling mode proved that adding the cooling system in the mold is an effective method for reduction of shrinkage defects.

Development of an automatic polishing system for aluminum wheel-hub surface

To improve polishing quality and cope with the shortage of skilled workers for aluminum wheel-hub surface polishing, an automatic surface polishing system with hierarchical control based on the teaching-playback method was presented. Multi-axis cutter location data (CL data) were generated with the teaching method. First, a helical tool path and a flexible polishing tool were adopted to achieve high quality and high efficiency; next, the initial irregular data were processed into continuous polishing CL data. The important factor affecting polishing quality, namely the interpolation cycle in the multi-axis CL data was calculated based on a constant removal rate. Results from polishing experiments show that the quality of automatic machine polishing is better and stabler than manual polishing.

Planetary scroll surface polishing method for aluminum wheel hub

Instead of manual polishing work for aluminum wheel hub （hub） surface, a new planetary scroll surface polishing method based on the rotation and revolution of hub in abrasives is presented in this paper. Since conventional barrel rotation polishing mode is unsatisfactory, shorter polishing period and lower energy consumption are expected. The surface polishing mechanism of the proposed method is ghen introduced. The influence of cutting velocity, cutting angle, abrasive on surface polishing quality and efficiency, as well as the correlation of the revolution velocity and the rotation velocity of hub are discussed. Experimental results show that high surface polishing quality and efficiency can be achieved with the new polishing method implying that a dustless clean working environment is realized.

Parametric Study on the Effect of Aspect Ratio of Selected Cooling Hole Geometries on the Mechanical Response of an Automobile Aluminium Alloy Wheel

Aluminium alloy wheels are increasingly popular for their light weight and good thermal conductivity. Cooling Holes (CH) are introduced to reduce their weight without compromising structural integrity. Literature is sparse on the effect of aspect ratio (AR) of CHs on wheels. This, work, therefore, attempts to undertake a parametric study of the effect of aspect ratio (AR) on the mechanical response of an aluminium alloy wheel with triangular, quadrilateral and oval-shaped CHs. Three-dimensional wheel models (6JX14H2ET42) with triangular, quadrilateral and oval shaped CH (each with CH area of 2229 mm2) were generated, discretized, and analyzed by FEM using Creo Elements/Pro 5.0 to determine the mechanical response at the inboard bead seat at different ARs of 1, 0.5, 0.33 and 0.25, each for quadrilateral-CH and oval-CH, at a static Radial Load of 4750 N and Inflation Pressures of 0.3 and 0.15 MPa, respectively. The study shows that the magnitude of stress and displacement is affected by shape and AR of CH. From the results, it could be established that oval-shaped-CH wheel at AR of 0.5 offers greater prospect in wheel design as it was least stressed and deformed and, that the CH combination with highest integrity was the oval-CH and quadrilateral-CH at AR of 0.5.

Fatigue and impact analysis and multi-objective optimization design of Mg/Al assembled wheel considering riveting residual stress

The multi-material assembled light alloy wheel presents an effective lightweight solution for new energy vehicles,but its riveting connection remains a problem.To address this problem,this paper proposed the explicit riveting-implicit springback-implicit fatigue/explicit impact sequence coupling simulation analysis method,analyzed the fatigue and impact performance of the punching riveting connected magnesium/aluminum alloy(Mg/Al)assembled wheel,and constructed some major evaluation indicators.The accuracy of the proposed simulation method was verified by conducting physical experiments of single and cross lap joints.The punching riveting process parameters of the assembled wheel joints were defined as design variables,and the fatigue and impact performance of the assembled wheel was defined as the optimization objective.The connection-performance integration multi-objective optimization design of the assembled wheel considering riveting residual stress was designed via Taguchi experiment,grey relational analysis,analytic hierarchy process,principal component analysis,and entropy weighting methods.The optimization results of the three weighting methods were compared,and the optimal combination of design variables was determined.The fatigue and impact performance of the Mg/Al assembled wheel were effectively improved after optimization.