【作者】 杜华平；

【导师】 程培元； 余世浩；

【作者基本信息】 武汉理工大学 ， 材料加工工程， 2004， 硕士

【摘要】 拉深是筒形件零件生产的核心工艺，工艺生产中必不可少。如何在保证质量的前提下降低极限拉深系数，减少工序，提高效率和降低成本，成为拉深成形工艺的主要研究问题之一。 本文利用塑性理论和数学方法提出了一种新的拉深凹模型腔曲面：在整个拉深过程中，拉深件侧壁上缘和凹模型腔曲面始终相切接触，这样降低凹模圆角半径造成的摩擦阻力和弯曲变形阻力，凹模曲面对毛坯变形区的作用力也有助于使它产生切向压缩变形，从而可以采用相对厚度较小的毛坯而不致起皱，达到减小极限拉深系数，减少工序，降低成本的目的。 通过分析拉深变形过程，在力学分析的基础上，提出了工件起皱失稳的条件，进而确定了曲面凹模拉深的起皱极限表达式。 通过数值模拟，预测起皱、拉裂、回弹，计算毛坯尺寸，计算成形力，估计模具磨损，优化润滑方案等。 通过拉深试验，证明采用这种新的曲面凹模拉深，可以极大的降低极限拉深系数，试验中得到的最小极限拉深系数为0.382。 通过拉深试验，分析了厚向异性系数R和硬化指数n对极限拉深系数的影响规律，分析了平面各向异性系数与凸耳率的关系。 本文对曲面凹模拉深工艺进行了深入的理论和试验研究，其结果丰富和发展了冲压成形基础理论。曲面凹模拉深与普通平端面凹模拉深相比，能够降低极限拉深系数，减少工序，提高效率和降低成本。文中得出的工艺参数对极限拉深系数的影响规律为实际生产中工艺选择及制订提供了可靠的理论依据。更多还原

【Abstract】 The drawing is the key technology on cup-drawing process, it is essential during blank forming. How to reduce limit drawing coefficient, cut down procedures, raise efficiency and reduce costs become one of the main research problems for drawing process on the premise of ensuring the quality of products.In this paper a kind of new curved die profile has been created by plastic theory and mathematical method: on the whole drawing process, the top of the side wall keeps in touch tangentially with the curved die throughout, which can reduce the friction resistance that caused by the round corner of the die and bending resistance, the force of the die profile on the blank deformation zone is also beneficial to make it bring on tangential compression deformation, thus it can use the blank which has a smaller relative thickness to draw without wrinkling, and beats target with reducing limit drawing coefficient, reducing procedures and lowering costs.By analyzing the forming process of the drawing, based on the analysis of mechanics, this paper has put forward the wrinkling criterion of the blank, deduced the wrinkling limit formula of the curved die sequentially.It can forecast wrinkling, fracture and spring back, compute the dimension of blank, compute the deforming force, estimate the abrasion of die, and optimize the lubrication scheme by numerical simulation.It has been proved that this kind of new curved die can reach smaller limit drawing coefficient by drawing experiment, the smallest limit drawing coefficient gotten in drawing experiment is 0.382.By drawing experiment, this paper has investigated the effect laws of anisotropic hardening parameter R and work hardening exponent n on limit drawing coefficient. And also has analyzed the relationship between the anisotropy in the blank plane and the earring ratio.The deeply theoretical and experimental research on drawing technology of curved die in this paper enriches and develops the fundamental theories ofstamping technology. Compared with general die, to use curved die can reduce limit drawing coefficient, reduce procedures, raise efficiency and reduce costs. The effect laws of process parameters on limit drawing coefficient which has been deduced in this paper provide a reliable theoretical basis for choice and design of the process in practice.更多还原