• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议> >STUDY OF FATIGUE INITIATION OF AUSTENITIC STAINLESS STEEL IN A HIGH TEMPERATURE WATER ENVIRONMENT AND IN AIR USING BLUNT NOTCH COMPACT TENSION SPECIMENS
【24h】

STUDY OF FATIGUE INITIATION OF AUSTENITIC STAINLESS STEEL IN A HIGH TEMPERATURE WATER ENVIRONMENT AND IN AIR USING BLUNT NOTCH COMPACT TENSION SPECIMENS

机译：用钝角紧凑张力试样研究高温水环境和空气中奥氏体不锈钢的疲劳始化

获取原文
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Fatigue life assessment procedures for components exposed to high temperature pressurised water environments are typically based on NUREG/CR-6909 or broadly similar codes (e.g. proposed ASME code case N-792). The effects of a high temperature water environment on the fatigue life are accounted for by simply adjusting the fatigue life in ambient temperature air by an environmental factor (F_(EN)). This adjustment assumes that the environment affects both initiation (nucleation) and propagation equally, which is potentially over-conservative. Blunt notch compact tension (CT) specimens (along with direct current potential drop (DCPD) crack detection) have been proposed as a means of determining the "true" fatigue initiation life, enabling the relative impact of the environment on initiation and growth to be characterised and the level of conservatism in the F_(EN) approach assessed. The current work uses a combination of finite element analysis and fatigue testing in both air and water to assess the feasibility of blunt notch CT testing to detect initiation and to quantify the environmental impact. This work indicates significant difficulties with the blunt notch CT test methodology both in terms of quantifying the applicable strain and in terms of detection of the very early stages of initiation which preclude the quantitative application of the technique to study true initiation. Qualitatively, the results suggest that there is still a significant impact of the high temperature water environment on the earliest detectable stages of crack growth in austenitic stainless steels; however the earliest defects detectible by DCPD techniques still involve a significant contribution from short crack growth. Nevertheless, the technique provides a valuable insight into initiation and residual life of components subjected to through wall strain gradients.
机译：暴露于高温高压水环境下的组件的疲劳寿命评估程序通常基于NUREG / CR-6909或大致相似的规范（例如，建议的ASME规范N-792）。高温水环境对疲劳寿命的影响可通过简单地通过环境因子（F_（EN））调整环境空气中的疲劳寿命来解决。此调整假设环境对启动（成核）和传播均具有同等影响，这可能过于保守。已经提出了钝口紧实张力（CT）标本（以及直流电势下降（DCPD）裂纹检测）作为确定“真实”疲劳起始寿命的一种手段，从而可以使环境对起始和生长的相对影响达到表征，并评估F_（EN）方法中的保守程度。当前的工作将有限元分析与空气和水中的疲劳测试结合使用，以评估钝口CT测试是否可行，以检测启动并量化环境影响。这项工作表明，在量化适用应变和检测启动的早期阶段方面，采用钝口CT测试方法存在重大困难，这使得无法定量应用该技术来研究真正的启动。定性地，结果表明，高温水环境对奥氏体不锈钢中裂纹扩展的最早可检测阶段仍具有重大影响。然而，最早可通过DCPD技术检测到的缺陷仍然涉及短裂纹扩展的重要影响。然而，该技术提供了对贯穿壁应变梯度的组件的初始寿命和剩余寿命的宝贵见解。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号