Determination of material properties on creep crack initiation (CCI) and creep crack growth (CCG) using small punch tests is still a virgin field to be exploited. Spanish and Czech researchers have carried out pioneering work and put forward an approach to correlate the notched specimen with the standard CT specimen. The advantage is that, the formulas of C*-integral for CT specimen are available and can be used directly. However, building a big data pool with both SP and CT tests within the creep region is a daunting task and hence it is worthwhile to derive C*-integral formulas for notched specimens themselves. The research is novel in that it proposes a methodology to derive the key parameter C*-integral for notched small punch specimens directly without supporting known CT tests. A 3D finite element model (FEM) for through-wall notched specimen with different crack lengths is build, and a general formulas for stress intensity factor (SIF) K, and limit load P_L are obtained to calculate C*-integral for notched specimen. Experiments on notched specimens are carried out for stainless steel Sanicro 25 at temperature 700 °C. By using general formulas derived in this study, the key parameter C*-integral is obtained. The relation between C*-integral and the creep initiation time t_i can be drawn as a straight line in a double logarithmic coordinate. The relation between C*-integral and the creep crack rate $\dot{a}$ appears to follow the same tendency. Material constants for CCI and CCG can be derived according to the power law using least square fitting. The proposed method is not fully developed and further validating experiments will be necessary to complete the research.

使用小冲头试验确定蠕变裂纹萌生 (CCI) 和蠕变裂纹扩展 (CCG) 的材料特性仍然是一个有待开发的处女地。西班牙和捷克的研究人员开展了开创性工作，并提出了一种将缺口标本与标准 CT 标本相关联的方法。优点是，CT标本的C *-积分公式是可用的，可以直接使用。然而，在蠕变区域内构建具有 SP 和 CT 测试的大数据池是一项艰巨的任务，因此值得推导出C* - 缺口试样本身的积分公式。该研究的新颖之处在于，它提出了一种方法，可以在不支持已知 CT 测试的情况下直接推导出缺口小冲头试样的关键参数 C*-积分。对于具有不同长度的裂纹穿墙缺口试样的三维有限元模型（FEM）是建立，和用于应力强度因子（SIF）一个通式K，和极限载荷P_大号获得，以计算c ^ * -积分为缺口试样. 在 700 °C 的温度下对不锈钢 Sanicro 25 进行了缺口试样的实验。通过使用本研究中推导出的一般公式，获得了关键参数C*-integral。C*-积分与蠕变起始时间t的关系_i可以绘制为双对数坐标中的一条直线。C*-积分与蠕变裂纹率的关系$\dot{\mathrm{一种}}$似乎遵循同样的趋势。CCI 和 CCG 的材料常数可以使用最小二乘拟合根据幂律导出。所提出的方法尚未完全开发，需要进一步验证实验才能完成研究。