Low pressure casting, as a mature casting process, has the characteristics of smooth filling, low cost, and good casting quality, and is widely used in the production of automotive components such as wheels. However, as the lightweight of auto parts is included in the development plan of “Made in China 2025”, more and more light metal such as magnesium and aluminum are used by manufacturers to manufacture auto parts. The application of these materials has accelerated the lightweight process of automotive components, but it has also put forward new requirements for low-pressure casting technology. How to use traditional low-pressure casting technology to produce parts that meet usage requirements has become a challenge for manufacturers.
In recent years, benefiting from the development of computer simulation technology, more and more manufacturers have begun to use casting simulation software to simulate low-pressure casting processes, in order to reduce costs and guide production. However, low-pressure casting involves multiple parameters, and due to people’s pursuit of aesthetics, the design of parts such as wheel hubs is becoming increasingly complex. Therefore, in the absence of optimization methods, it is difficult for researchers to obtain reasonable process parameters.
(1) The low-pressure casting process parameters have a significant impact on the formation of wheel hub castings. For the porosity of castings, the preheating temperature of the lower mold has the greatest impact, followed by the preheating temperature of the upper mold, pouring temperature, and filling speed; For the secondary dendrite arm spacing and solidification time, the weight of influencing factors from high to low is pouring temperature, upper mold preheating temperature, lower mold preheating temperature, and filling time.
(2) For the aluminum alloy wheel hub studied, the optimization results of low-pressure casting process parameters are pouring temperature 650 ℃, upper mold preheating temperature 280 ℃, lower mold preheating temperature 340 ℃, and filling time 20 seconds.
(3) The use of optimized process parameters has basically eliminated the pore defects in the casting, but there is still room for optimization in terms of solidification time and secondary dendrite arm spacing.
In response to these issues, taking an A356 aluminum alloy passenger car hub as an example, the optimization objectives are porosity, secondary dendrite arm spacing (SDAS), and solidification time. Taguchi method, signal-to-noise ratio analysis method, and numerical simulation verification are used to explore the effects of pouring temperature, upper mold preheating temperature, lower mold preheating temperature, and filling time on the optimization objectives, aiming to obtain a reasonable set of parameters, Used as a guide for actual low-pressure casting wheel hub production.