【摘要】 利用SEM、EDS、TEM和万能试验机、布氏硬度计分析了供货态及700℃时效不同时间（500、800、1500、2500、3650 h）TP347HFG钢的组织性能变化规律。结果表明，TP347HFG钢在700℃时效过程中，析出相总量随时效时间的变化规律为：y=0.060-9.956×10^-5x+2.912×10^-7x²-2.707×10^-11x³-7.719×10^-15x⁴;TP347HFG钢原始试样析出相为细小的一次Nb（C, N）相，时效500 h后有M₂₃C₆碳化物在晶界析出并长大，时效时有3650 h少量σ相出现。时效500 h时，晶界上细微的第二相抑制了晶界的迁移，提高了硬度和强度，但是降低了材料塑性；时效800 h后，硬脆相M₂₃C₆碳化物的析出和孪晶数量减少降低了材料的强度；时效1500 h后，细小二次Nb（C, N）起到了弥散强化作用，使得钢的强度增加、塑性降低，时效至3650 h时，随着析出相的粗化，材料硬度值下降、强度少量降低、塑性略有提升。更多还原

【Abstract】 By using SEM, EDS, TEM, universal testing machine and Brinell hardness tester, the changes in microstructure and properties of TP347HFG steel in as-received state and different aged states（aged at 700 ℃ for 500, 800, 1500, 2500, 3650 h） were analyzed. The results show that the relationship of total amount of precipitated phases vs aging time during the aging process of the TP347HFG steel at 700 ℃ is as follows: y=0.060-9.956×10^-5x+2.912×10^-7x²-2.707×10^-11x³-7.719×10^-15x⁴. The precipitated phase of the as-received TP347HFG steel is fine primary phase Nb（C, N）. After aging for 500 h, M₂₃C₆ carbides precipitate and grow at the grain boundaries, and a small amount of σ phase appears after aging for 3650 h. After aging for 500 h, the fine second phase on the grain boundaries inhibits grain boundary slip, improves the hardness and strength, but reduces the material plasticity. After aging for 800 h, the precipitation of hard and brittle M₂₃C₆ carbides and the decrease in twinning quantity reduce the strength of the steel. After aging for 1500 h, the fine secondary Nb（C, N） plays a role in dispersion strengthening, increasing the strength and reducing the plasticity of the steel. When aged to 3650 h, with the coarsening of precipitated phases, the hardness value of the steel is decreased, the strength is slightly decreased, and the plasticity is slightly improved.更多还原