材料期刊网

利用Z参数方法分析了T91/P91(9Cr--1Mo--V--Nb)钢高温持久性能数据的统计分布规律. 结果表明:形状、热处理工艺等不同的T91/P91钢的高温持久性能数据交替重叠地分布在以应力σ--TTP(时间--温度参数)关系主曲线为中心的数据带中, 而表征T91/P91钢持久性能数据分散性的Z参数服从正态分布. 基于Z参数法对材料高温持久性能的可靠性分析结果, 提出了T91/P91钢的σ--TTP--可靠度R曲线、 σ--断裂时间t_r--R曲线和许用应力[σ]--温度T--R曲线.预测结果与NRIM及ECCC公开的实验数据均符合良好.

Life prediction is an important issue for components serviced at high temperature from both economic and safety reasons. For the purpose to correlate creep rupture data, the time--temperature parameter (TTP) method is often used to condense all the rupture data obtained at various stresses and temperatures to a narrow band. Because of uncertainty factors in materials and experiment conditions, creep rupture data generally exhibit dispersity which can be described using a so--called Z--parameter method. The current paper performs a statistical analysis for creep rupture data of T91/P91 (9Cr--1Mo--V--Nb) steel, a kind of ferritic steels widely used in power plants recently by Z--parameter method. The results indicate that all the creep rupture data distribute in a narrow band in stress σ--TTP plot. The distribution of Z--parameter which is used to represent the dispersion of the creep rupture data follows normal distribution. σ--TTP--reliability R, σ--rupture time t_r--R and allowable stress [σ]--temperature T--R curves are proposed based on Z--parameter method. The results exhibit a good agreement with the experimental data promulgated by NRIM and ECCC.