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Estimation Scheme of Residual Lives for elevated Temperature Components Using Total Information of Nano and Macro Sizes

利用纳米和宏观尺寸总信息的高温部件剩余寿命估计方案

基本信息

批准号：
17560062
负责人：
KOBAYASHI Ken-ichi
金额：
$ 2.24万
依托单位：
Chiba University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

A new testing apparatus where constant load is directly applied to a very small disc-type specimen is developed to evaluate creep lives of components at elevated temperatures : Small Punch Creep (SPC) testing apparatus. Since failure of structural components mainly breaks out around maximum damaged portion, and heavily damaged components dominate the residual life of structural systems, a methodology to assess the local damage and residual life in components under creep temperature have been required. However, conventional uni-axial creep specimens need a certain amount of volume, and this often causes a difficulty to repair specific devices after sampling uni-axial creep specimens. Dimensions of the disc-type specimen here employed are very small : 10 mm in diameter and 0.5 mm in thickness. After designing and installing the new SPC testing apparatus, as series of SPC tests are conducted using super duralumin. It is clarified that the primary and the secondary creep regimes occupy most of the creep deformation, and that the tertiary creep appears just before fracture. Furthermore it is shown that creep rupture lives obtained in the SPC test have a good correlation with those from uni-axial creep tests.Since the initial SPC apparatus has not had a specific vessel to prevent oxidation for ferritic steels over the creep temperature regimes, in the second fiscal year a new SPC testing apparatus was developed where a thin walled pipe and a small vessel were attached to perform little oxidation atmosphere. Unfortunately oxide scale about 20μm in thickness was formed on the surface of disc specimens due to either a lack of the flow of Argon gas or inadequate. However a relation between the load in the SPC test and the stress in the creep test is described as a power low function.

本文介绍了一种新的高温蠕变试验装置-小冲杆蠕变试验装置。该装置将恒定载荷直接施加到一个非常小的圆盘试样上，以评估高温下构件的蠕变寿命。由于结构构件的失效主要发生在最大损伤部位附近，而严重损伤构件又决定了结构系统的剩余寿命，因此需要一种评估蠕变温度下构件局部损伤和剩余寿命的方法。然而，传统的单轴蠕变试样需要一定量的体积，这往往会导致难以修复特定的设备后，采样单轴蠕变试样。这里使用的圆盘型试样的尺寸非常小：直径为10 mm，厚度为0.5 mm。设计并安装了新型SPC试验装置，采用超硬铝材料进行了一系列SPC试验。它是澄清，第一和第二蠕变制度占据了大部分的蠕变变形，和第三蠕变出现之前，断裂。此外，它表明，在SPC测试中获得的蠕变断裂寿命有一个很好的相关性与那些从单轴蠕变tests.Since最初的SPC设备没有一个特定的容器，以防止铁素体钢在蠕变温度制度的氧化，在第二个财政年度开发了一个新的SPC测试设备，其中一个薄壁管和一个小容器连接到执行很少的氧化气氛。但由于氩气流量不足或流量不足，在圆盘试样表面形成了约20μm厚的氧化膜。然而，SPC试验中的载荷与蠕变试验中的应力之间的关系被描述为低次幂函数。