Study On The Precision Forming Of HAI 60-1-1 Aluminum Brass Thrust Bearing Blocks

Aluminum Brass Thrust Bearing Blocks are important component parts in turbocharger. Its quality impacts on the life of turbocharger directly, at present, much domestic manufacturers use the powder metallurgy way or machining the cast bronze producing the parts, its quality is poor. Foreign manufacturers have begun to use high wear-resistant aluminum brass producing the parts by extrusion way. Its performance has been greatly enhanced. This paper achieved the purpose to form the Aluminum Brass Thrust Bearing Blocks by the extrusion process. This process can greatly improve the product quality and saving raw materials and reduce costs. This paper solves the following specific issues:1. Finding the proper temperature and the proper strain rate of metal deformation.According to the compression experiments to HAI 60-1-1 high wear-resistant aluminumbrass done by predecessor, we analyzed the metal's mechanical properties and microstructure by under the different strain rates and different temperatures, we fond the 750°C is the properextrusion temperature , the microstructure under 0.1S^-1 strain rate is better.2. The reason of the folding defects and the ways to avoid.In the processes of forming the part, there are two folding defects in the inner wall of the Block. We used the numerical simulation and physical test methods to prove that the reason is the metal around the folds flowing by the "clenched hand" trend. The ways to avoid it is adding convex on corresponding position of the punch in order to break the "clenched hand" trend of metal's flow. The proper size of the convex is: outline is same to the step of punch, Maximum curvature is 58.5°and minimum thickness is 5mm.3. Proved the metal contacting with the punch's top have a radial flow or not.In the processes of the part's forming, if the metal contacting with the punch's top hasn't radial flow, the outline of the eight petals grooves on the Block should be same with the out line of eight convexes on the top of punch, on the other hand, if the metal contacting with the punch's top has radial flow, the outline of the eight petals grooves should be elongated. So, the metal contacting with the punch's top have a radial flow or not will determined if we can form it by one step, then we used the numerical simulation and physical test to prove that there are no radial flow exist, forming it by one step is available.4. Finding the proper extrusion speed.We use numerical simulation to simulate the extrusion process in different extrusion speed, analyzed the force of punch, analyzed the different equivalent stress and equivalent strain, we found that when the extrusion speed is 0.1m/s, the work of the punch is smallest and the residual stress is smallest, organization of microstructure is more evenly.Finally, we summed up a set of Aluminum Brass thrust bearing blocks' extrusion process.