为了尝试将小冲孔试验技术应用于服役设备寿命预测,对服役后的Cr5Mo以及12Cr1Mo V进行不同载荷下的小冲孔蠕变试验,与常规单轴蠕变试验结果比对,建立了服役材料的小冲孔蠕变寿命分析方法。分析结果表明:高温、恒载下小冲孔曲线存在明显的蠕变减速、恒速、加速阶段,小冲孔试验具有替代传统蠕变试验的能力。随着载荷的增大,小冲孔稳态蠕变速率不断增加,而蠕变断裂时间则逐渐缩短。稳态蠕变速率与载荷之间可以使用Norton方程表示,而断裂寿命则与小冲孔载荷之间则存在幂函数关系。基于Larson-Miller法,建立蠕变断裂寿命与温度、载荷之间的参数化关系从而实现基于小冲孔试验的服役材料蠕变寿命外推。
Creep properties of in-service Cr5Mo and 12Cr1MoV under different loads were analyzed by small punch creep tests.Compared to the results of conventional creep tests, creep life prediction method based on small punch test was established. Results showed that there existed apparent stages of deceleration,constant speed and acceleration in the small punch creep curves, which had the ability to replace the traditional creep tests. The steady creep rate gradually increased while the rupture life decreased with the increase of load. The relationship between steady creep rate and load could be described by Norton equation. Meanwhile,there was a power function relation between rupture life and load under constant temperature.In order to realize life extrapolation for in-service materials by small punch test,the creep rupture time was analyzed by temperature and load based on the Larson-Miller equation.