Abstract: The thermal deformation behavior of 420 mm casting slab of 690 MPa high-strength steel for ocean engineering (/% ：0. 12 〜0. 15C,1.05 ~ 1.20Mn,0.5 ~0. 7Cr, 1. 0 ~ 2.0Ni,0. 5 ~0. 6Mo,0. 3 ~0. 6Cu,0.015 〜0.035Nb, 0. 008 〜0. 020Ti ,0. 04 ~0. 07Alt) with 20% deformation and strain rate 0. 05 ~ 5 s^-1 at 1 000 ~ 1 100 ℃ has been tested studied by using Gleeble 3800 thermal simulation machine to get true stress-strain curves, strain-hardening rate-deformation stress curves, thermal deformation constitution equation and dynamic recrystallization thermal activation energy of the steel. Results show that at same test temperature with increasing strain rate the corresponding deformation stress increases ； while with increasing deformation temperature the deformation stress decreases ； and the dynamic recrystallization thermal activation energy of the steel is 499 954. 0 J/mol.

Key words: 690 MPa High-Strength Steel for Ocean Engineering, Thermal Deformation at 1 000 ?1 100 ℃ , , Strain Rate, Stress-Strain, Dynamic Recrystallization

摘要： 通过Gleeble 3800热模拟机试验研究了690 MPa高强度海洋工程用钢(/%:0.12~0.15C,1.05~1.20Mn,0.5~0.7Cr,1.0~2.0Ni,0.5~0.6Mo,0.3~0.6Cu,0.015~0.035Nb,0.008~0.020Ti,0.04~0.07Alt)420mm连铸板坯,在1 000~1 100℃,20%形变量,应变速率0.05~5 s^-1时的热变形行为,得出该钢真应力-应变曲线,应变硬化率-变形曲线、热变形本构方程和动态再结晶热激活能。结果表明,在同一试验温度下,随着应变速率的增加,变形应力相应的增加;而随着变形温度的增加,变形应力相应的降低;该试验钢的动态再结晶激活能为499 954.0 J/mol。