热处理工艺对2Cr11Mo1VNbN耐热钢组织和性能的影响

 为了解决2Cr11Mo1VNbN钢短时持久性能低的问题，采用OM、SEM、TEM等手段研究了不同淬火和回火工艺下超超临界叶片用2Cr11Mo1VNbN马氏体耐热钢的组织、室温力学性能及短时持久性能。结果表明，随着淬火温度的提升，强度和硬度增加，冲击吸收功在1 075 ℃后呈降低趋势；1 125 ℃淬火+660 ℃回火后，该钢的649 ℃+228 MPa的短时持久性能明显提升。回火温度高于660 ℃，强度和硬度降低，冲击吸收功增加，短时持久性能急速衰减。微观组织分析表明，提高淬火温度，合金中的一次粗大铌的碳化物更多地固溶到基体中，析出数量减少，固溶强化作用增加，强度和硬度增加，使合金的弱化区减少，提高了材料抵抗高温变形的能力，改善了合金的持久性能。

Effect of heat treatment process on microstructure and property of 2Cr11Mo1VNbN heat resistant steel

In order to solve the problem of low creep fracture time of 2Cr11Mo1VNbN steel，the microstructure，room temperature mechanical properties and creep fracture time of 2Cr11Mo1VNbN martensitic heat resistant steel for ultra supercritical blades under different quenching and tempering processes were studied by means of OM，SEM and TEM. The results showed that the strength and hardness of 2Cr11Mo1VNbN heat resistant steel increased with the increase of quenching temperature，and the impact absorbing energy decreased when quenching temperature exceeded 1 075 ℃. Quenching at 1 125 ℃ and tempering at 660 ℃，the creep fracture time at 649 ℃+228 MPa was obviously improved. With the increase of tempering temperature，the strength and hardness decreased，the impact absorbing energy increased，and the creep fracture time degraded rapidly. Microstructural analysis shows that increasing the quenching temperature，more NbC，a coarse primary carbide formed in smelting，solid dissolves into the matrix. Meanwhile the carbide precipitation reduces，so the matrix strength was elevated. High alloy strength is accompanied by a decrease of the weakened zone of the alloy，thus results in an increase of creep fracture time.