Abstract: 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 Q_d=110.99 kJ/mol.

Key words: ultra-deep well oil well pipe, hot compression deformation, constitutive equation, deformation activation energy