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金属粘塑性成形过程泛指必须考虑应变速率影响的成形过程。目前,这种成形方法已成功地应用于生产难变形材料的重要宇航锻件,因此,引起了压力加工领域的研究人员的关注。鉴于金属在超塑性状态下成形是典型的粘塑性成形过程,本文试图以超塑性板材胀形过程为对象,对粘塑性成形过程的分析方法进行探索。作者在对考虑加工硬化影响的胀形过程所进行分析的基础上,提出一种超塑性板材胀形过程的分析方法,用这种方法可以模拟分析胀形压力为常数以及应变速率恒定的胀形过程。还可以对从过程的最后阶段到原始状态的全过程进行模拟。因此,本文提出的方法可以提供超塑性板材胀形过程的主要信息。引入作者提出的相对压力p~*,可使影响起塑性板材胀形过程的因素归结为p~*和m两个因素,同时使所得结果具有普遍意义。理论分析和计算结果表明,壁厚均匀性主要取决于m值,因而可以通过控制坯料内温度场以达到要求的壁厚均匀性。本文还提供了用作者提出的方法确定的线图,以便确定最佳的胀形压力或胀形压力随时间变化的关系。
The metal viscoplastic forming process generally refers to the forming process that has to take into account the influence of the strain rate. At present, this method of forming has been successfully applied to the important aerospace forgings that produce difficult-to-deformable materials, and therefore has drawn the attention of researchers in the field of pressure processing. Since metal is a typical viscoplastic forming process in the superplastic state, this paper attempts to explore the analysis method of viscoplastic forming process based on the bulging process of superplastic sheet. Based on the analysis of the bulging process which takes into account the influence of work hardening, the author presents a method of analyzing the bulging process of superplastic plates. With this method, the bulging pressure can be simulated and analyzed with constant bulging pressure and constant strain rate process. You can also simulate the entire process from the final stage of the process to the original state. Therefore, the method proposed in this paper can provide the main information of superplastic sheet bulging process. By introducing the relative pressure p ~ * proposed by the author, the factors that affect the process of plastic sheet bulging can be attributed to p ~ * and m factors, and the results obtained have universal significance. The theoretical analysis and calculation results show that the thickness uniformity is mainly determined by the value of m, so the desired thickness uniformity can be achieved by controlling the temperature field in the blank. This article also provides a line chart determined by the authors’ proposed method to determine the optimal bulge or bulge pressure over time.