S30408钢应变强化过程声发射实验研究

发布时间：2018-05-29 06:21

本文选题：S30408钢 + 声发射　；参考：《东北石油大学》2017年硕士论文

【摘要】：奥氏体不锈钢由于其优秀的力学性能和抗腐蚀性能而被广泛应用于承压设备领域,人们通过应变强化工艺使奥氏体不锈钢承压设备变薄、变轻的同时更应保证其安全性,而应变强化工艺的优劣直接影响着承压设备的承载能力。应变强化加载速率是应变强化过程的一个重要控制参数,因此深入了解不同加载速率下应变强化过程内部组织的塑性变形程度对承压设备的制造和安全服役具有重大意义。本文采用声发射技术监测不同加载速率下的应变强化过程,研究S30408板状标准比例试件在应变强化过程的声发射特性。本文主要内容概括如下:(1)综述了奥氏体不锈钢应变强化技术的研究和发展现状,详细阐述了不同条件的应变强化工艺对材料细观组织、力学性能的影响,并根据目前声发射技术对检测奥氏体不锈钢缺陷的应用,对论文进行可行性分析,明确了研究思路和技术路线。(2)制定了S30408钢应变强化声发射监测方案,实验数据显示,材料加载阶段与声发射特征参数存在明显的相关性。利用声发射特征参数累积量归一化处理和相关声发射特征参数分析法对不同加载速率下的应变强化过程进行分析,阐述了不同加载速率下声发射累积参量的变化趋势,同时得到了不同应变量区间内声发射幅值分布的差异。(3)制定了S30408钢循环加载拉伸试验的声发射监测方案,利用不同加载速率下S30408钢声发射的凯塞尔效应来确定材料对所受应力的记忆能力。结果表明,当加载速率为2mm/min时,本文所采用的试件表现出了良好的凯塞尔效应,材料能够准确的记忆受载历史,表明在该加载速率下材料内部塑性变形充分。(4)在以上研究的基础上,对不同加载速率下声发射信号的幅值、上升时间、持续时间进行了关联性分析,根据幅值、上升时间、持续时间的分布特征,对声发射信号进行分类统计,达到了利用声发射技术监测本文所采用S30408试件的应变强化效果优劣的目的。
[Abstract]:Austenitic stainless steel is widely used in the field of pressure equipment because of its excellent mechanical properties and corrosion resistance. The strain strengthening technology directly affects the bearing capacity of the pressure equipment. Strain hardening loading rate is an important control parameter in the strain strengthening process. Therefore, it is of great significance to understand the plastic deformation degree of the internal structure of the strain strengthening process at different loading rates for the manufacture and safe service of the pressure equipment. In this paper, acoustic emission (AE) technique is used to monitor the strain hardening process at different loading rates, and the acoustic emission characteristics of the S30408 plate-like standard specimen in the strain hardening process are studied. The main contents of this paper are summarized as follows: (1) the research and development of strain strengthening technology of austenitic stainless steel are reviewed, and the effect of strain strengthening process under different conditions on the microstructure and mechanical properties of austenitic stainless steel is described in detail. According to the application of acoustic emission technology to detect the defects of austenitic stainless steel, the feasibility analysis of the paper is carried out, and the research idea and technical route are clarified. The S30408 steel strain-enhanced acoustic emission monitoring scheme is established. The experimental data show that, There is a significant correlation between the loading stage and the acoustic emission characteristic parameters. The process of strain strengthening at different loading rates is analyzed by means of normalized treatment of acoustic emission characteristic parameter cumulants and correlation acoustic emission characteristic parameter analysis, and the variation trend of cumulative acoustic emission parameter under different loading rate is expounded. At the same time, the acoustic emission monitoring scheme of S30408 steel under cyclic loading is obtained. The Queisser effect of acoustic emission of S30408 steel at different loading rates was used to determine the memory ability of the material to the stress. The results show that when the loading rate is 2mm/min, the specimen used in this paper shows a good Queisser effect, and the material can accurately remember the loading history. The results show that the plastic deformation of the material is sufficient at the loading rate. (4) on the basis of the above research, the amplitude, rise time and duration of acoustic emission signal under different loading rates are analyzed. According to the amplitude, rise time, rise time, According to the distribution of duration, the acoustic emission signals are classified and counted. The purpose of using acoustic emission technology to monitor the strain strengthening effect of the S30408 specimen used in this paper is achieved.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG142.71

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