亚稳态奥氏体不锈钢标准椭圆形封头温冲压温度研究

发布时间：2018-01-02 21:06

  本文关键词：亚稳态奥氏体不锈钢标准椭圆形封头温冲压温度研究　出处：《浙江大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 奥氏体不锈钢 椭圆形封头 温冲压成形 温度

【摘要】：亚稳态奥氏体不锈钢标准椭圆形封头在工业中被广泛使用,为保证产量,该类封头主要由冲压工艺生产。然而,冷冲压成形过程中板料会发生形变诱发马氏体相变并伴随着强度的升高和塑性的降低,不利于其安全使用,热冲压成形的成本又较高,相比之下,温冲压成形即能够限制冲压成形后封头材料的马氏体量,其成本也明显低于热冲压成形,是较为合适的选择。目前,关于封头温冲压成形的研究较少,温冲压温度的制定缺乏理论依据,难以依据需方对封头的马氏体量的要求来确定合适的冲压成形温度,这导致了成本的增高。另外,不了解冲压温度对成形后封头材料力学性能的影响,又在无形中增加了安全隐患。此外,由于缺乏有效的方法计算冲压成形过程中的温度下降,也导致了冲压过程中的温度下降难以被纳入考虑。由此可见,研究冲压成形温度对冲压成形过程中材料的马氏体相变以及冲压成形后材料的力学性能的影响规律,建立冲压成形过程中温降的计算方法,将冲压成形过程中的温降纳入考虑之中,对保证温冲压成形封头的安全性和经济性具有重要的意义。综上所述,本文在浙江省重点科技创新团队项目(项目编号2010R50001)、中央高校基本科研业务费专项资金(项目编号2014FZA4024)、中国博士后科学基金(项目编号2014M551731)等的支持下,主要针对S30408材料,完成工作如下：(1)基于不同批次304材料在不同温度下的拉伸试验结果,分析了材料形变诱发马氏体相变随变形温度的变化规律,同时考虑材料化学成分的影响,建立了材料形变诱发马氏体相变与变形温度、材料化学成分之间的关联公式,基于此,初步给出了建议的冲压温度下限值为90℃。(2)在第2章的基础上,通过材料试验,研究了材料力学性能随其预变形温度的变化规律,并通过对比各个温度下预变形后材料的力学性能,进一步给出了建议的冲压温度下限值,且仍为90℃。(3)进行了封头的温、冷冲压成形试验。通过试验对比了相同规格的温、冷冲压成形封头的塑性变形率以及成形后各封头材料的马氏体量及其冲击性能,进一步验证了以90℃为建议的冲压温度下限值的合理性。(4)基于ABAQUS对温冲压成形过程进行热固耦合数值仿真,对比试验结果,建立了封头温冲压成形过程的数值计算方法。在此基础上,采用数值方法分析了不同温冲压条件对温降的影响规律,结合传热学知识,建立了适用于计算温冲压成形后封头直边段温度的计算方法。最后,结合本文所给出的建议的冲压温度下限值,给出了考虑温降的冲压温度确定方法。
[Abstract]:The standard elliptical head of metastable austenitic stainless steel is widely used in industry. In order to ensure the output, this kind of head is mainly produced by stamping process. The deformation induced martensite transformation will occur in the cold stamping process with the increase of strength and the decrease of plasticity, which is not conducive to its safe use, and the cost of hot stamping is higher than that of hot stamping. Warm stamping can limit the amount of martensite after stamping, and its cost is obviously lower than that of hot stamping, so it is a more suitable choice. At present, there are few researches on head warm stamping. The establishment of temperature stamping temperature is lack of theoretical basis, it is difficult to determine the appropriate stamping temperature according to the requirement of martensite quantity of the head, which leads to the increase of cost. Do not understand the impact of stamping temperature on the mechanical properties of the head material after forming, but also increase the safety hidden danger in the invisible. In addition, due to the lack of effective methods to calculate the temperature drop in the stamping process. It also leads to the temperature drop in the stamping process is difficult to be taken into account. The effect of stamping temperature on the martensite transformation and mechanical properties of the material during stamping process was studied, and the calculation method of temperature drop in stamping process was established. Taking the temperature drop in the stamping process into account, it is of great significance to ensure the safety and economy of the warm stamping head. This article is in Zhejiang Province key science and technology innovation team project (project number 2010R50001N), the central university basic scientific research business expense special fund (project number 2014FZA4024). Supported by the China postdoctoral Science Foundation (Project No. 2014M551731), it is mainly aimed at material S30408. Based on the tensile test results of different batches of 304 materials at different temperatures, the variation of deformation-induced martensite transformation with deformation temperature is analyzed. At the same time, considering the influence of material chemical composition, the correlation formula between deformation induced martensite transformation and deformation temperature and material chemical composition is established. The suggested lower limit of stamping temperature is 90 鈩，

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