A356 Aluminum Alloy Wheel Hub Grading Quenching Deformation Control Process And Experimental Research

Currently,automotive lightweight has become one of the main research directions in the world automotive industry.On the premise of meeting the requirements of size and performance as well as aesthetic appearance,the main purpose of weight reduction is to improve the topology structure.The topology improvement and weight reduction will also reduce the structural stiffness of the wheel,which makes it more difficult to control and detect the deformation of the aluminum alloy wheel during heat treatment,and the uneven deformation of the wheel during heat treatment reduces the positioning accuracy of the subsequent machining,and the large uneven deformation during heat treatment is mainly offset by increasing the machining allowance,however,this method not only increases the consumption of blank material,but also affects the positioning accuracy of the machining.However,this method not only increases the consumption of billet material,but also affects the yield and service safety of the wheel with poor machining and positioning accuracy.In this paper,based on the analysis of the structural characteristics of aluminum alloy wheels and the deformation characteristics in the pool bath quenching,it is found that the existing lightweight wheels have a warpage deformation of 0～2 mm on the wheel rim and the same radial elliptical deformation on the wheel rim after quenching,and a new graded quenching method using "spray/spray + pool bath vibration" is proposed in combination with the existing wheel production process.A new graded quenching method using "spray/spray + bath vibration" is proposed to reduce the deformation of the wheel during quenching.Based on the new quenching process scheme,a relevant wheel heat treatment experimental platform was independently developed and built to study the deformation pattern of aluminum alloy wheels under different spray quenching process conditions with the help of three deformation detection methods: handheld 3D laser scanner,CMM and3 D contour laser scanner.The deformation characteristics of the outer rim,rim,spokes and wheel center of the wheel by the graded quenching process were experimentally studied by changing the process parameters of spray/spray quenching.The results showed that the graded quenching process of spray/spray + pool vibration could improve the uneven deformation of the wheel,in which the maximum improvement of the warpage deformation of the outer rim was up to 47.2%;the maximum improvement of the elliptical deformation of the rim was up to 47.9%.Finally,the effect of the graded quenching process on the mechanical properties and metallographic organization of the wheel was studied.The results showed that the wheel structures could meet the international requirements for hardness and strength on the basis of the above deformation improvement,and the metallographic organization of the corresponding parts did not differ significantly from that of the traditional bath immersion quenching,and finally an upgrade plan was proposed for the field device based on the graded quenching process.