Effect Of Cooling Medium On The Casting Technology And Property Of The Aluminum Alloy Whell Hub

In order to reduce the loss and waste of the material and energy, automotivelightweight design has been the development direction for car modernization. In this work,the aluminum alloy wheel hub was selected as the research object, the casting technologiesunder the different cooling systems were studied, and the effect of cooling medium on themicrostructure and property was researched. At last, the reliability of aluminum alloywheel hub was evaluated by bending fatigue test, radial fatigue test and impact test.On the low-pressure processing, the calculated results show that, the SDAS value inthe center of the wheel hub is50μm, while the largest SDAS value of the spoke is near thebolt hole and the rim, which is between46μm to49μm. The SDAS value of the rim isbetween30μm to44μm. So the material property of the rim is more excellent than that ofthe spoke and center of the wheel hub. The experimental results indicate that, with theincrease of the top mold cooling capacity, the temperature difference between the moldand the casting increases, the casting cooling rate increases, which lead to thesolidification crystallization time of the casting is shortened and the structure is compact.Therefore, the properties improve to a certain degree.The macroscopic morphologies of the aluminum alloy wheel hubs, which are lowpressure casted under air-cooled and water-cooled are identical. However, from themicrostructures, the average grain size of the air-cooled wheel hub is56μm while that ofthe water-cooled wheel hub is36μm. So, compared with air-cooled wheel hub, thewater-cooled wheel hub has the high tensile strength and yield strength. The productioncost and production efficiency of air-cooled wheel hub are2.5yuan/piece and88pieces/8hours, while those of water-cooled wheel hub are0.5yuan/piece and115pieces/8hours,which indicate that compared with air-cooled technology, the water-cooled technologydecreases80%costs and improves13.4%production efficiency. Moreover, after bendingfatigue test, radial fatigue test and impact test, there is no cracks appear on the twoaluminum alloy wheel hub, which indicate that the both can meet the requirements.