超深井V170级高强钢的热变形行为

Hot deformation behavior of V170 grade high-strength steel for ultra-deep wells

根据传统非API标准的油井管套管的化学成分,自主设计了一种V170级超深井油井管套管钢。热模拟试样取自试验钢热轧后的轧板,利用MMS-300多功能热力模拟试验机进行热模拟压缩试验,研究试验钢在应变速率分别为0.01、0.1、1、5、10 s^(-1),变形温度分别为800、900、950、1000、1100℃条件下的热压缩变形行为。结果表明,该材料软化机制主要为动态回复以及动态再结晶,在高的变形温度及低的应变速率下更容易发生动态再结晶,这是因为温度较高时增加原子扩散、提高位错运动的驱动力,使再结晶过程更容易进行。利用Arrhenius双曲正弦函数建立试验钢峰值应力本构方程,并通过计算得到该试验钢热变形激活能Qd=110.99 kJ/mol。

According to the chemical composition of traditional non-API standard oil country tubular goods(OCTG),a V170 grade ultra-deep well OCTG steel was independently designed.The thermal simulation specimens were taken from the rolled sheets of the tested steel after hot rolling,and the MMS-300 multi-functional thermal simulation test machine was used for thermal simulation compression experiments.The hot compression deformation behavior of the tested steel was studied under the conditions of strain rates of 0.01,0.1,1,5,and 10 s^(-1),respectively,and deformation temperatures of 800,900,950,1000 and 1100℃.The results show that the softening mechanism of the material is mainly dynamic recovery and dynamic recrystallization,and the dynamic recrystallization is more likely to occur at high deformation temperature and low strain rate.Because the higher temperature increases atomic diffusion and increases the driving force of dislocation motion,which makes the recrystallization process easier.The peak stress constitutive equation of the tested steel is established by using the Arrhenius hyperbolic sine function,and the calculated hot deformation activation energy of the tested steel is Qd=110.99 kJ/mol.