ABSTRACT The effect of tungsten–molybdenum (W–Mo) balance on creep life has been investigated for five heats of martensitic 9Cr steel with 1.5 % Mo equivalent (= 1/2W + Mo) at 600, 650 and 700°C. The combination of W and Mo concentrations in the present steel is 3W–0Mo, 2.8W–0.1Mo, 2.4W–0.3Mo, 1.8W–0.6Mo and 0W–1.5Mo. The time to rupture tr exhibits a monotonous increase with increasing the W–Mo balance parameter 1/2W/(1/2W + Mo), namely, with increasing W concentration and concomitantly with decreasing Mo. The increase in tr with increasing 1/2W/(1/2W + Mo) becomes less significant at long times. The precipitation of Fe2(W,Mo) Laves phase takes place preferentially at prior austenite grain boundaries during creep, which enhances the grain boundary (GB) precipitation hardening. The amount of Laves phase increases with increasing 1/2W/(1/2W + Mo). The coarsening of Laves phase takes place at long times during creep, which reduces the GB precipitation hardening.

中文翻译：

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W-Mo平衡对9Cr钢长期蠕变寿命的影响

摘要 在 600、650 和 700°C 下，研究了 5 炉马氏体 9Cr 钢的钨钼 (W-Mo) 平衡对蠕变寿命的影响，该钢具有 1.5% 钼当量（= 1/2W + Mo）。目前钢中W和Mo浓度的组合为3W-0Mo、2.8W-0.1Mo、2.4W-0.3Mo、1.8W-0.6Mo和0W-1.5Mo。断裂时间 tr 随着 W-Mo 平衡参数 1/2W/(1/2W + Mo) 的增加而单调增加，即随着 W 浓度的增加和 Mo 的减少，tr 的增加随着 1/2W 的增加而增加/(1/2W + Mo) 在很长一段时间内变得不那么重要。Fe2(W,Mo) Laves 相在蠕变过程中优先发生在原奥氏体晶界，这增强了晶界 (GB) 沉淀硬化。Laves 相的量随着 1/2W/(1/2W + Mo) 的增加而增加。