The Precision Forging Process Bore Analytical Model And Experimental Verification

The precision radial forging process is now widely used in the forging of the barrel rifling for its good quality. There are still a lot of questions need to solve in china, such as determining manufacturing process parameters rationally, broadening its application and raising product quality. During the radial forging process, the forging pressure, stress state and material flows are influenced by forging rates, the die shape, the friction coefficient between surfaces and material property. Their relationship is very complex. It is hard to study them by a single method to provide reference for the practical process. It is necessary to use analytical method, numerical method and combining with verified test.In the present paper, based on the slab-method mechanical model of the radial forging process of tube rifles, combined with the continuum equation of neutral plane and the axial balance equation of the whole system, the position of neutral plane, the forging load and front-push forces were predicted by solving the mechanical model. Besides, friction shear factor can be evaluated.The upper bound solution was used in the radial forging of tube to build velocity field, strain rate and deformation work rate equation. By minimizing the deformation power with regards to the location of the neutral plane, both the forging load and the location of neutral plane are predicted.To verify the accuracy of the mechanical models, the practical forging experiment was done, and there was a good agreement between the two sets results. The comparison of the mechanical model based on the slab method and the upper bound theory was conducted.The strain equation in the radial forging process of tube rifles under compound angles hammer was build.2D FEA model was created by the ABAQUS software to analyze the stain state of tube during the deformation process. A good agreement was found between the two sets results.Based on the mechanical model of the slab method, single factor and the Taguchi method are employed to study the effect of process parameters on forging loads and the position of neutral plane in detail which provided reference for choosing optimum process variables in the practical process. The optimum conditions are predicted via the Taguchi method.The research work showed that:the mechanical model based on the slab method had better prediction for the forging load and the position of neutral plane, and the accuracy was improved with the increasing of forging ratio. The strain equation built here also predicted the strain of the radial forging process well. So the work in the paper can provide a good tool for the engineer during determining the process parameters for the radial forging of the barrel rifling.