Research On Couple Effects Of Material Parameters And Feed Velocity Of Mandrel On Cold Ring Rolling

Cold ring-rolling process is an advanced complex local plastic forming technics with multi-factors couple effects. The couple effects between material parameters and feed velocity are very important for the process. Therefore, they are investigated by the numerical simulation method in this dissertation. In the paper, hardenability value, yield strength and Young's modulus are chosen respectively in the range of 0.065~0.5, 100~450MPa and 35~120GPa. The constant feed velocities of the mandrel are chosen in the scope of 1.22 ~9.75mm/s. The finite element analysis software-ABAQUS is used for the simulation. Elastic-plastic dynamic finite element method is adopted for the characteristics of the cold ring-rolling process. The main results are as follows:The rules that inhomogeneous deformation and fishtail coefficient of the shaped ring change with the feed velocity are mainly affected by hardenability value, while yield strength and Young's modulus have little influence on the rules. For the material whose hardenability value is less than 0.2, when the feed velocity increases from 1.22mm/s to 3.66mm/s, the inhomogeneous deformation degree and fishtail coefficient fall down quickly; when the feed velocity increases from 3.66mm/s to 6mm/s, the inhomogeneous deformation degree also falls down, but the downtrend becomes slower; and when the feed velocity is more than 6mm/s, the inhomogeneous deformation degree has little change. The fishtail coefficient changes scarcely when the feed velocity increases from 3.66mm/s to 9.75mm/s.The roll force rises with the increment of feed velocity, hardenability value and yield strength, while Young's modulus has little effect on it. Moreover, yield strength and Young's modulus have little influence on the rule that the roll force change with the amount of feed, while hardenability value has much influence on it. If hardenability value is more than 0.1, roll force is increasing with the increment of the amount of the feed. However, roll force is changeless when hardenability value is less than 0.1.The investigation in the dissertation puts forward a guideline how to choose appropriate feed velocity for different material: the value of feed velocity depends onthe hardenability value, the effects by yield strength and Young's modulus can be neglected. If hardenability value is less than 0.2, feed velocity can be chosen at around 6mm/s, and if hardenability value is more than 0.2, lower feed velocity in the range 1.22 ~9.75 mm/s is better as long as production efficiency is satisfied.The results obtained above provide a reference when choosing feed velocity for different material in cold ring roll process.