ABSTRACT The effect of W-Mo balance and boron nitrides (BN) on creep rupture ductility has been investigated for five heats of 9% Cr steel with 1.5% Mo equivalent, 0.003% boron and 0.05% nitrogen at 600oC, 650oC and 700oC. The maximum time to rupture was 68,718 h at 650oC. The reduction of area (RA) slightly decreases for up to about 8000 and 1000 h at 600 and 650oC, respectively, while it significantly decreases above those. The BN particles are responsible for the degradation in RA at low stresses and long times by accelerating the formation of creep voids. At high stresses and short times, the RA decreases with increasing time to rupture and with increasing W concentration and concomitantly with decreasing Mo concentration. The rupture ductility is evaluated by using a semi-logarithmic diagram of the RA and total elongation, showing the necking dominant and void swelling dominant regions.

中文翻译：

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W-Mo平衡和氮化硼对9Cr钢蠕变断裂塑性的影响

摘要 在 600oC、650oC 和 700oC 下，研究了 5 炉 9% Cr 钢、1.5% Mo 当量、0.003% 硼和 0.05% 氮的 W-Mo 平衡和氮化硼 (BN) 对蠕变断裂延展性的影响。在 650oC 下，破裂的最长时间为 68,718 小时。在 600 和 650 oC 时，面积 (RA) 的减少量分别在约 8000 和 1000 小时内略有下降，而在高于这些时则显着下降。BN 颗粒通过加速蠕变空隙的形成，在低应力和长时间下导致 RA 的降解。在高应力和短时间下，RA 随着破裂时间的增加和 W 浓度的增加以及 Mo 浓度的降低而降低。断裂延展性是通过使用 RA 和总伸长率的半对数图来评估的，