Abstract: To study the effect of ausforming on hardenability in steel 09MnNb used for L485QS sour service pipeline, different ausforming processes were performed and the subsequent hardenabilitis and microstructures were tested. It revels that three types of microstructures could be gained when ausforming at temperature from 850°C to 1 100 °C and under deformation degree e from 0.2 to 0. 8. In the transformation of microstructures,it was a leading role of the deformatiorm temperature that acicular ferrite, thin-strip bainite and thick-lath bainite were mainly obtained respectively when the temperatures at 900°C . and below,from 950 °C to 1000 °C and at 1050 °C or higher. Increasing deformation degrees could promote transformation of acicular ferrite in unrecrystallization zone and thin-strip bainite in partial recrystallization respectively ,but in fully recrystallization zone make the lath bainite either coarsed or refined. When ausforming used of steel 09MnNb at temperatures from 950 °C to 1000°C and under deformation degree of ε ≥0.4 or above,the microstructure consisted fully of thin-strip bainite could be obtained so as a higher and more stable hardenabilities could be achieved, which may be beneficial to the properties control when tempered in following.

摘要： 对L485QS酸性管线用钢09MnNb进行不同工艺的热形变淬火试验,测试淬硬性并观察相应的组织。结果表明,试验钢在850～1 100℃进行0.2～0.8变形水淬后可获得三种类型的组织,变形温度是影响组织转变类型的主导因素,当温度≤900℃时,主要获得针状铁素体,当温度为950～1 000℃时,主要获得细条状贝氏体,当温度≥1050℃时,主要获得粗大的板条状贝氏体。增大变形量在未再结晶和部分再结晶区分别促进针状铁素体转变和细条状贝氏体转变,在完全再结晶区使板条状贝氏体组织粗细不一致。采用09MnNb钢在950～1 000℃进行ε≥0.4的热变形淬火时,可获得以细条状贝氏体为主的淬火组织,以及较高且稳定的淬硬性,并有利于后续回火性能的调控。