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在Gleeble-3500热模拟机上测定了Nb-V微合化金中碳非调质钢在不同冷却速率下的膨胀曲线,并联合金相-硬度法,绘制出了Nb-V试验钢的动态CCT曲线。依据所绘试验钢动态CCT曲线,对试验钢在不同冷却速率下组织的转变转变情况进行了分析。结果表明:冷却速率低于2℃/s时,Nb-V钢的显微组织为铁素体和珠光体,冷却速率超过2℃/s时,钢中组织可以观察到贝氏体,随着冷却速率的增加贝氏体含量也明显增加;冷却速率超过10℃/s时,组织中开始出现马氏体;冷却速率超过15℃/s后Nb-V钢显微组织全部为马氏体。贝氏体转变的临界冷却速率为7~10℃/s,马氏体转变的临界冷却速率为10~15℃/s。
The swelling curve of Nb-V microalloying green carbon non-quenched and tempered steel at different cooling rates was measured on a Gleeble-3500 thermal simulator. The dynamic CCT of Nb-V test steel curve. Based on the dynamic CCT curves of the test steel, the transformation and transformation of the test steel under different cooling rates were analyzed. The results show that when the cooling rate is lower than 2 ℃ / s, the microstructure of Nb-V steel is ferrite and pearlite. When the cooling rate exceeds 2 ℃ / s, the bainite can be observed in the steel, When the cooling rate exceeds 10 ℃ / s, the martensite begins to appear in the microstructure. When the cooling rate exceeds 15 ℃ / s, the microstructure of the Nb-V steel is all martensite. The critical cooling rate of bainite transformation is 7 ~ 10 ℃ / s, and the critical cooling rate of martensite transformation is 10 ~ 15 ℃ / s.