FEM Simulation Analysis And Experimental Studies On Hot Precision Forming Of Cannonball Body Semiproduct

This project takes source from the "95" science and technology pre-study project "cannonball body semiproduct precision forming" of weapon industrial equipment Group Company.Cannonball body semiproduct precision forming is to product cannonball body semiproduct meeting the quality request with the possibly little material.This project takes the big body blank of five-nine type long-distance blasting shrapnel with 130 mm as study object. The cannonball is a kind of large caliber shrapnel and is being produced with large bulk, possessing representative. At present, the material utilization ratio is merely 48.5 percents, the trimming arc rate is 100 percents, the wall thickness difference is commonly between 3 and 4 mm (the maximum is 12 mm), and the rate of spoiled is 12 percents, therefore, it has great significance to improve material utilization ratio, reduce quantity of machining, and decrease production cost. The main technology indexes are: material utilization ratio is not less than 64 percents, trimming arc rate is not more than 25 percents, the amount of wall thickness difference under 2.5 mm is not less than 80 percents,(the maximum is not more than 4 mm), and the non-defective unit rate is not less than 96 percents. The material utilization ratio is the core of technology indexes.To achieve the above target, the total technology project of this project is put forwarded: "precision blank preparation, soaking, full pressing, shallow punching of thick wall, multiple die ironing in short distance and controlled inside-shape technology with nosing".The hot forming process of cannonball body semiproduct is mainly composed of four operations: pressing, punching, ironing, and shell nosing. Process is complicated and the shape, the amount of deformation after forming of each operation needs reasonable design. If traditional calculation method is adopted, the workload is very high and calculation accuracy is low, it's difficult to meet the request of precision forming analysis and optimization. Taking a comprehensive view of the calculation methods which have existed in metal forming process, the finite element method－FEM is the most extensive in application and effective numerical method. Among them the rigid-visco plastic finite element method is a most suited computer numerical simulation method to solve the problem of metal plastic forming in high temperature.The study method of this project is to perform computer numerical simulation for the whole process of cannonball body hot ironing forming and forecast the question or defect may appears, through adopting rigid-visco plastic finite element method (FEM) and using American advanced software DEFORM, then the technology and die parameters are optimized, which provides theory basis for hot forming, equipment and die design of cannonball body semiproduct. On this basis, equipment and die are manufactured, and the technology experiment is performed directly according to the cannonball body material with scale 1:1. The smooth success of study is acquired by the experimental examination performed in No.383 factory. The experimental results fit mutually with the simulation data, and finally the new production technology of optimized cannonball body semiproduct hot forming is identified. This testifies that the new provided precision forming technology of cannonball body semiproduct is feasible and effective.The experimental results suggest that this study achieves the cannonball body semiproduct precision forming. The blanking weight of cannonball body semiproduct was reduced to 49.5 kilograms from original 37.5 kilograms, each cannonball saves raw material 12 kilograms, the material utilization ratio is improved to 64 percents from original 48.5 percents, the trimming arc rate is between 11.28 percents and 23.68 percents, less than 25 percents, the amount of wall thickness difference of body semiproduct under 2.5mm are reached more than 90 percents, the maximum is less than 2.9mm. The tactics denseness degree is greatly improved, and the ma...