研究了轧制态、正火态X70管线钢和AISI304不锈钢的室温蠕变行为, 发现在数种应力水平下此2种钢主要呈现为速率递减的对数蠕变特征. 室温蠕变和拉伸实验的关系表明, 室温蠕变实验中的加载过程与拉伸实验相同, 且室温蠕变开始时的应变速率与加载过程结束时的相等. 在此基础上, 结合室温蠕变本构方程和描述拉伸实验中应力-应变关系的Ramberg-Osgood公式, 提出了基于外加应力估算结构钢室温蠕变的方法. 该方法得到的X70管线钢和AISI304不锈钢室温蠕变量的估算结果与实验值符合得较好, 误差均在2倍因子之内.
Room temperature creep (RTC) behaviors of the as-rolled (AR) and normalized (Nor) X70 pipeline steel as well as the AISI304 stainless steel were investigated. At different stress levels, their RTCs mainly showed the feature of logarithmic creep with continuously falling rate. By comparing RTC with tensile tests, it was found that the loading process of RTC test was the same as the tensile test, and the strain rate at the start of RTC was equal to that at the end of loading process. Based on these results and by combining the constitutive equations of RTC with the Ramberg-Osgood equation, which is generally used to describe the stress-strain relationship in tensile tests, an approach to estimate RTC strain was presented as a function of the applied stress. On applying it to the X70 pipeline steel and AISI304 stainless steel, it was indicated that the estimated results of RTC were well consistent with the experimental data and that all the errors were within a factor of 2.
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