一种预测TP347H钢长时持久强度的方法

An Approach for Long-term Creep-rupture Strength Prediction of Steel TH347H

基于多区LMP法,利用TP347H钢的高温(700℃、750℃)短时(≤5×103 h)试验数据预测其长时持久强度(600～750℃,5×103～2×105 h).结果表明:在应力-时间图中根据σ/σTS的特定比值对应力分区,用低应力-长时区LMP参数中的C值计算长时持久强度,其预测值与真实值吻合良好;与传统的单区LMP法相比,多区LMP法的应用不仅显著降低了持久强度的过估倾向而且大大缩短了试验时间,为这类钢的长时持久强度评估提供了准确而有效的方法.

On the basis of a multi-region Larson-Miller parameter method newly proposed, long term creep rupture strengths （600-750 ℃, 5 ×10^3 -2×10^5 h） were successfully predicted for steel TP347H by using the data from tests lasting up to only 5 × 10^3 h at 700 ℃ and 750 ℃. Results show that in the plot of stress vs. rupture life, a set of creep rupture data can be divided into several data sets according to the specific value of σ/σrs, SO that the value C is unique in each individual data set; by using the C value in LMP corresponding to the lower-stress longer-time region, long-term creep rupture strengths have been assessed for the steel, of which the predicted results agree well with that of actual measurements. Compared with conventional single region LMP method, the proposed approach may not only avoid overestimation of creep rupture strength, but also shorten the time needed for creep rupture tests. This may serve as a reference for prediction of long-term creep-rupture life of similar steels.