Analysis Of Steel Wheel Rim Rolling And Spoke Power Spinning Forming Process

Tubeless steel wheel is an important component of heavy vehicles, weldedtogether by the rims and spokes. The rims forming is a complex multi-step process,which including flaring process and three rolling processes. The stagger spinningprocess of automobile spoke with three rollers which including the characteristics ofpower spinning and common spinning processes. To improve the quality of theworkpiece, rims and spokes manufacturers often rely on experience or use trial anderror, but the cycle is too long and the cost is too high. Finite element simulationtechnology can keeping track of the material flowing in forming process, has greatadvantages in terms of pre-assessment workpiece formability, improving processdesign and product quality. In this paper, in order to investigate the deformationmechanism of workpiece in the forming process，predict and control the productdefects, provide a theoretical support for improving the product quality, using thefinite element simulation software named ABAQUS to analyze the rims and spokesforming process.The elastic-plastic finite element simulation models including simulate flaringprocess and three rolling processes are established, and the forming processes areanalyzed based on ABAQUS in the paper. Some crucial issues such as selectingimposing boundary conditions for side guide roller, applying load curves, andtransferring data of stress and strain among the whole processes are introduced. Thecorresponding simulating results such as distribution and variation of equivalentstress, strain are analyzed.By analyzing the stress states of workpiece in flaring process, find that theexcessive hoop stress will cause the weld cracking, and then propose the concept ofaverage maximum hoop tensile stress. With the increase of friction coefficient or theyield strength of material, the average maximum hoop tensile stress of workpieceincreases, the tendency of the workpiece welding joint cracking increases. Theinfluence of feed rate, friction coefficient, material thickness, the rolling speed of theroller on the forming quality of the workpiece in the first rolling process have been studied, find that increasing the feed rate is beneficial to forming quality of rimsrolling; increasing friction coefficient would exacerbate thinning of groove fillet,while reducing the rolling speed will help it. To solving the asymmetrical flangedefects of rims forming process, the design of first pass rolling dies is improved in thepaper. Numerical simulation analysis shows that deviation rim defects have beengreatly improved after the mold improved.Based on ABAQUS, the elastic-plastic finite element simulation model of thestagger spinning process of automobile spoke with three rollers is established.Methods of imposing boundary conditions and trajectory curves of rollers areintroduced. The corresponding analysis results such as distribution and variation ofequivalent stress, equivalent strain and thickness are obtained. Results show that themaximum equivalent stress is in the areas of blank contacting with the core mouldfillets and the outer edge regions of spoke. Equivalent strain distributeshomogeneously in circumferential direction of the spoke, and equivalent strain ringsare formed. Thickness is unchangeable in the central area of the spoke. It has thesame value in circumferential direction, but changes in the radial direction.The deformation mechanism of workpiece is studied during process of spokesstagger spinning. The workpiece is classified to non-deforming zone, deformed zone,the main deformed zone and the undeformed zone, which based on the third invariantof deviator stress tensor. Then the flowability of material is analyzed during formingprocess. The influence of rolling speed, stagger value, friction coefficient and feedingspeed on spokes forming quality are researched. The flowability of material alonegeneratrix is in direct proportion to rolling speed; the inhomogeneous deformation ofmaterial is proportional to axial stagger value; the material flowability along thegeneratrix direction improved by increasing the friction coefficient; The effect offeeding speed on material forming is complex. In the earlier stage of forming, thegrowth of feed speed is conducive to the flow of material, while the material isaccumulated as the excessive feed speed later.