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通过高Nb、V或Ti(~0.1%),低Mo(≤0.2%)微合金化设计,在经TMCP工艺后用恒载荷拉伸实验测定了Fe-C-M-Mo(M=Nb、V或Ti)系合金钢的失效温度。用EBSD分析了TMCP后样品中的界面密度,用TEM观测了恒载拉伸实验后样品中的纳米析出相。结果表明:在Fe-C-V/Nb钢中添加约0.2%Mo使其在280 MPa恒载荷拉伸升温过程中的失效温度提高约40℃。小角度界面为MC型析出相形核析出提供了有利位置,加速了MC相的析出,在升温过程中细小弥散的MC相在小角度界面形核析出起到了良好的高温沉淀强化作用,提高了耐火钢的失效温度。含Mo的Ti-Mo钢具有较高的小角度界面密度,导致其中MC型析出相析出较快,因此具有最高的失效温度,Nb-Mo钢次之,V-Mo钢因小角度界面密度最小使其在高温下MC相析出的动力学减缓,因此失效温度最低。
The Fe-CM-Mo (M = Nb, V or (2 +) or (V)) is determined by the constant load tensile test after the TMCP process through the microalloying design with high Nb, V or Ti (~ 0.1%) and low Mo Ti) is the failure temperature of the alloy steel. The interface density in the samples after TMCP was analyzed by EBSD. The nano-precipitates in the samples after the constant-load tensile test were observed by TEM. The results show that adding about 0.2% Mo into Fe-C-V / Nb steel increases the failure temperature by about 40 ℃ during the process of 280MPa constant load tensile heating. The small-angle interface provides a favorable location for the precipitation of MC-type precipitates and accelerates the precipitation of the MC phase. The finely dispersed MC phase forms a good high-temperature precipitation strengthening effect at the small-angle interface during the heating process, improving the fire resistance Steel failure temperature. Mo-containing Ti-Mo steels have higher small-angle interfacial densities, leading to rapid precipitation of MC-type precipitates and thus have the highest failure temperature, followed by Nb-Mo steels, and V-Mo steels with the smallest inter- The kinetics of precipitation of MC phase at high temperature is slowed, so the failure temperature is the lowest.