Defining a negligible creep temperature curve for Gr. 91 steel

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• 作者：Stefan Holmströ ; m ^{stefan.holmstrom@ec.europa.eu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Negligible creep ; Low temperature ; Gr. 91 ; P91 ; X10CrMoVNb9-1 ; Design rules
• 刊名：International Journal of Pressure Vessels and Piping
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：146
• 期：Complete
• 页码：198-202
• 全文大小：612 K

文摘

Time independent rules for design can be applied if the design temperature of a component is restricted below the negligible creep temperature (T_NEC). The T_NEC curve describes the time and temperature limits below which accumulated creep strain and damage is insignificant at a specified reference or design stress. For the ferritic/martensitic steel Gr. 91 (X10CrMoVNb9-1) there is currently no T_NEC curve available in the nuclear design code RCC-MRx. In this paper the T_NEC curve for Gr.91 is defined using a new methodology developed in the European FP 7 project MATTER. The T_NEC curve is based on time to 0.2% creep strain data. Supporting test data from low temperature (375–500 °C) creep and tensile tests are presented and assessed. The T_NEC curve can alternatively be constructed by using time factor corrected creep rupture data. These time factors can be used for evaluating the safety against significant creep at both reference and design stress. The presented methodology is will be used for determination of T_NEC curves for the next revision of the EN-13445.