身管线膛精密径向锻造的锻透性分析

Analysis of Forging Penetration of Barrel Rifling in Precision Radial Forging Process

身管内膛加工质量是保证身管武器射击精度的重要因素,为了提高身管内膛加工质量,利用有限元模拟方法研究身管内膛线膛部位的锻透性,并建立线膛锻透成形极限图。以5. 8mm口径线膛身管为研究对象,应用有限元软件Abaqus,建立了身管径向锻造三维有限元模型,分析了膛线成形中应力与应变的变化规律。结合内膛锻不透缺陷的表现形式,建立了以径向和周向塑性应变为表征的身管内膛膛线锻透的判断准则,即阳线上各点周向塑性应变变化率为0和径向塑性应变小于0.根据判断准则,得到以锻造比及毛坯径比为表征的身管锻透极限图,并通过试验验证了锻透极限图的准确性。试验结果表明:模拟的毛坯外径与内径比为3. 7时锻透的锻造比极限值为21. 18%,在试验的未锻透与锻透的锻造比之间,证明了锻透判断准则和锻透极限图的合理性。

The precision forging technology of barrel rifling is an advanced manufacturing process,and the machining quality of barrel bore is an important factor to ensure the initial velocity and firing accuracy of barrel weapon.The defect of precision forging rifled bore is mainly that the material in therifling lands is not full.This state of the defect is commonly referred to as non-penetration.In the actual processing,it is difficult to detect the forging state of barrel.Therefore,it is of great significance to study the forging penetration of barrel and formulate the reasonable process parameters.The precision forging of 5.8 mm rifled barrel is studied.A three-dimensional finite element model of radial forging of barrel is established by using the finite element software Abaqus.The contact status between bore and mandrel,contact normal stress,and variation of plastic strain of bore during the forging process are analyzed in detail.The criteria of forging penetration are established according to the expressive form of the unpenetrated defect.The criteria are that the change rate of the circumferential plasticity strain at each point on the rifling lands should be zero and the radial plasticity strain should be less than zero.According to the judging criteria,the forging limit diagram of barrel characterized by the forging ratio and diameter ratio of blank is obtained,and the accuracy of the limit diagram is verified through experiment.The test results show that the proposed judging criteria can be used to study the penetration of barrel.