Research On Improving The Quality Of Wide And Large Shape Motorcycle Hub

Aluminum alloy, with its advantages of light weight, corrosion resistance, easy machining and its good- looking, is widely used in the manufacture of motorcycle wheel hub. As an important security part of vehicle, the quality requirements of the wheel hub are very high. The wheel hub needs to have good safety performance and high mechanical properties, and due to the requirements of lightweight of motorcycle, wheel hub is getting thinner, its shape becomes more complex. With the development of large delivery capacity motorcycle, the use of wide hub is becoming more and more popular. Due to reasons such as the complex shape, the casting of wide hub is relatively difficult. Some defects appear during the process of wide hub casting in WanFeng Motorcycle Wheel C., LTD. In the background of improving the quality of the casting and the casting process, this paper made the following research.Through the FLOW-3D numerical simulation software, the hub's solidification during casting is simulated, and the results show that the junction of spokes and rim cannot get feeding and leads to defects. To eliminate the defects, three kinds of schemes are designed :(1) thickening the riser;(2) adding cooling channel on the outside of the rim;(3) setting copper cold iron at the junction of rim and spokes. Results show that adding long copper cold irons(scheme 3) can promote the order of casting solidification, and the defects are basically eliminated. It is the most effective improvement scheme. By thickening riser and adding water channel on the outside of rim cannot eliminate the defects completely.The metal mold temperature controller(referred to as HKJ- 2015) has been designed to be used in WanFeng company. The controller is as the core of time relay and temperature control instrument, and the temperature is real-time acquired and the controller makes judgment to control the opening and closing of the cooling water. So that it can make the temperature of the mould changes in a certain range. The qualified rate of the products increases from 50% to 95%.In order to improve the performance of the wheel hub further, the effect of short-term ultrasonic treatment on the quality of the aluminum is explored. Results show that when the ultrasonic processing power is 0.17w/g, the pouring temperature is 640 ? and the processing time is 30 s, the casting can get the best performance. Compared to samples without ultrasonic processing, the tensile strength increases 39.5% and elongation increases 100%. At the higher temperature(700 ?) or shorter ultrasonic processing time(pouring temperature at 640 ? and 630 ?, the processing time of 5 s and 8 s) ultrasonic treatment has no obvious improvement on the mechanical properties.T6 short-time heat treatment process was improved. The solution time is shortened from 6 h to 15 min and solution temperature increases from 535 ? to 540 ?. The sample's tensile strength of this technology gets 263.88 MPa and the elongation approaches 5.75%, meeting the mechanical performance index(tensile strength of 250 MPa, the elongation of 5%) of WanFeng company. It finds that the eutectic silicon in alloy organization with heat treatment becomes smaller and rounder compared to the as-cast microstructure, and the eutectic silicon of quenching samples is more rounder then that of air cooling samples.