国产核燃料锆合金格架刚凸冲压工艺参数优化

Optimization of Dimple Stamping Process Parameters of Zirconium Alloy Grid for Domestic Nuclear Fuel

摘要: 在科研人员的技术攻关下，我国已经具备某型号核燃料锆合金格架的国产化制造能力，包括带材、条带的制造以及格架的组装、焊接能力。为进一步优化国产锆合金条带关键特征的成形性能，针对国产锆合金条带上的刚凸特征，基于Dynaform软件开展模拟仿真，并设计了正交模拟试验，将最大减薄率、最大主应变和成形高度作为评价指标，优化了冲压速度、压边力、摩擦系数和冲压间隙等工艺参数。在一定的冲压工艺参数范围内，影响格架刚凸冲压的工艺因素中，最大减薄率、成形高度偏差受冲压速度和压边力影响较大，受摩擦系数和冲压间隙影响较小，而最大主应变反之。结合冲压试验验证，采用优化后的工艺参数方案，最大减薄率降低8.3%，成形高度与名义值偏差减小40%，刚凸特征减薄率与成形高度偏差均有减少，与模拟仿真结果具有一致性。针对刚凸上非线性特征难以检测问题，使用包络图法检验刚凸合格性，检验结果表明格架刚凸较好被包络在包络曲线中，可认为该工艺参数满足刚凸冲压工艺要求。该冲压工艺参数为实际生产加工指导提供了依据。

Abstract: Under the technical breakthroughs of researchers, China has developed the capability to domestically manufacture a certain zirconium alloy grid, including the production of strips as well as the assembly and welding capabilities of the grid. To further optimize the formability of key features of domestically produced zirconium alloy strips, the dimple characteristics on the zirconium alloy strips were simulated based on Dynaform software, and orthogonal simulation experiment were designed, and the maximum thinning rate, maximum principal strain and forming height were used as evaluation indexes, and the influence of process parameters such as punching speed, edge pressing force, friction coefficient and punching clearance on the forming quality of dimple was studied. Within a certain range of stamping process parameters, among the process factors affecting the dimple stamping of the grid, the maximum thinning rate and the forming height deviation are greatly affected by the stamping speed and the edge pressing force, and the friction coefficient and stamping clearance are less affected, while the maximum principal strain is the opposite. Based on the verification of the stamping experiment, the optimized process parameter scheme was adopted, resulting in a maximum thinning rate reduction of 8.3%, a reduction of 40% in the deviation between the forming height and the nominal value, and a qualified dimple feature size with reduced thinning rate and forming height deviation, which is consistent with the simulation results. In order to solve the problem that the nonlinear features on the dimple are difficult to detect, the envelope diagram method is used to test the qualification of the dimple, and the test results show that the dimple of the grid is better enveloped in the envelope curve, and it can be considered that the process parameters meet the requirements of the dimple stamping process. The actual production and processing guidance of the stamping process parameters provides a basis.