P91钢的瞬态蠕变行为分析

Analysis of transient creep behavior of P91 steel

系统研究了P91钢在600和620℃下不同应力水平时的瞬态蠕变变形行为。通过将蠕变过程中材料内部位错与析出相间相互作用耦合于内应力,结合Orowan方程,应用非线性拟合的方法确定了瞬态蠕变模型参数,对P91钢在瞬态蠕变阶段的变形曲线进行了数值模拟。结果显示,数值模拟结果与试验数据较为吻合,表明应用该模型对瞬态蠕变状态进行研究具有一定的可行性。同时,结合瞬态蠕变时间和归一化瞬态应变对温度和应力的依赖关系,进一步证实了P91钢在600和620℃下,135~175 MPa的应力范围内的瞬态蠕变主要是受位错攀移过程控制。

Transient creep deformation behavior of the P91 steel under different stress levels at 600℃and 620℃respectively was systematically studied.By coupling the interaction between internal dislocations and precipitated phases in the material during creep process to the internal stress,combined with Orowan equation,the transient creep model parameters were determined by the nonlinear fitting method,and the deformation curve of the P91 steel in the transient creep stage was numerically simulated.The results show that the numerical simulation results are in good agreement with the experimental data,indicating that it is feasible to apply the model to study the transient creep behavior of the P91 steel.At the same time,combined with the fact that the transient creep time and normalized transient strain depend on the temperature and the stress,it is further confirmed that the transient creep of the P91 steel at 600℃and 620℃respectively and in the stress range of 135-175 MPa is mainly controlled by the dislocation climbing process.