PCrNi3MoV钢静态CCT曲线的测定与分析

在Gleeble-1500D热模拟试验机上,利用膨胀法测定了PCrNi3MoV钢在不同冷却速度下过冷奥氏体连续冷却时的膨胀曲线。采用切线法获得了其相转变点,用Origin软件绘制PCrNi3MoV钢过冷奥氏体连续冷却相转变曲线(CCT曲线)。结果表明:PCrNi3MoV钢的临界点:Ac1和Ac3分别为720℃和850℃;Ms和Mf分别为300℃和160℃。对于过冷奥氏体,当冷却速度较慢时,如0.05~0.07℃/s时主要发生铁素体、贝氏体和马氏体转变;而冷却速度中等时,如0.1~1℃/s时发生贝氏体和大量马氏体转变;当冷却速度较大时,如50℃/s时只发生马氏体转变。随着冷却速度的增加,维氏硬度从500 HV迅速增加,当冷速大于1℃/s以后趋于平稳并达到800 HV。

Measurement and analysis of static CCT curve of PCrNi3MoV steel

The expansion curves of supercooled austenite of PCrNi3 MoV steel under continuous cooling at different cooling rates was measured by expansion method on a Gleeble-1500 D thermal simulation tester. The phase transition point of the steel was obtained by tangent method, and the continuous cooling phase transformation curve(CCT curve) of supercooled austenite of the PCrNi3 MoV steel was drawn by Origin software. The results show that the critical points of the PCrNi3 MoV steel are as follows: Ac1 and Ac3 are 720 ℃ and 850 ℃, and Ms and Mf are 300 ℃ and 160 ℃, respectively. For supercooled austenite, when the cooling rate is slow, such as 0.05-0.07 ℃/s, the transformation of ferrite, bainite and martensite mainly occurs;when the cooling rate is medium, such as 0.1-1 ℃/s, a smaller amount of bainite and a large amount of martensite transformation occurs;when the cooling rate is high, such as 50 ℃/s, only martensite transformation occurs. With the increase of cooling rate, the Vickers hardness of the steel increases rapidly from 500 HV, and when the cooling rate is more than 1 ℃/s, the Vickers hardness tends to be stable and reaches 800 HV.