针对圆形钢管无凹模冲孔后管材塌陷量大、成形质量差的问题,采用有限元分析法研究管材无凹模冲孔变形机理,分析比较不同冲头对冲孔变形量大小和冲裁力的影响,提出渐进剪切成形的新思路,设计改进型冲头。经数值模拟和工艺试验证明,采用改进型冲头可以减小冲孔后管材塌陷量,降低冲裁力,提高冲裁件质量。 Aiming at the problem of large amount of pipe collapse and poor forming quality after the round steel pipe without die punching, the die deformation mechanism of the die without die was studied by using the finite element analysis method. The difference of punching hole deformation and punching force The paper puts forward a new idea of ​​progressive shear forming and designs an improved punch. The numerical simulation and process tests show that the improved punch can reduce the amount of pipe collapse after punching, reduce the punching force and improve the punching quality.