ABSTRACT The influence of boron nitride (BN) particles, W and Mo concentrations and creep test conditions of stress, temperature and test duration on the creep ductility parameter λ in UK R5 has been investigated for five heats of W-Mo-balanced 9Cr steel with 1.5% Mo equivalent at 600, 650 and 700 oC. With increasing time to rupture t r, the λ at first decreases only a little bit, then increases for up to a time showing a maximum peak and finally significantly decreases. The BN particles are responsible for the decreases in λ at long times by accelerating the formation of creep voids. The evaluation of creep rupture ductility based on the λ should be restricted to the long-time region at low stresses after reaching a maximum peak in λ, where the λ decreases with increasing t r mainly by a decrease in total elongation.

中文翻译：

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化学成分和蠕变试验条件对W-Mo平衡9Cr钢UK R5蠕变延展性参数λ的影响

摘要 研究了氮化硼 (BN) 颗粒、W 和 Mo 浓度以及应力、温度和试验持续时间等蠕变试验条件对 UK R5 中蠕变延展性参数 λ 的影响，对 W-Mo 平衡的 9Cr 钢的五炉次进行了研究。在 600、650 和 700 oC 下为 1.5% Mo 当量。随着断裂时间的增加 tr，λ 起初仅下降一点点，然后增加到显示最大峰值的时间，最后显着下降。BN 颗粒通过加速蠕变空隙的形成而导致 λ 在长时间内降低。基于 λ 的蠕变断裂延展性评估应限于在 λ 达到最大峰值后低应力下的长时间区域，其中 λ 随 tr 的增加而减小，主要是由于总伸长率的减小。