ZHANG Jie
,
CAI Qing-wu
,
WU Hui-bin
,
ZHANG Kun
,
WU Bo
钢铁研究学报(英文版)
A new kind of Mn-Mo-Nb-Cu-B bainite steel which satisfied mechanical demands of E690 offshore plate steel was designed. The effect of two processes——thermomechanical control process (TMCP)+tempering (T) and thermomechanical control process (TMCP)+reheating and quenching (RQ)+tempering (T)——on microstructure and mechanical properties were studied by means of scan electron microscope (SEM), transmission electron microscope (TEM) and electron back scatter diffraction (EBSD). The results showed that optimal mechanical properties were available when tempering at 550 ℃ for both processes. The microstructure of the TMCP+T treated sample tempering in the range of 450 to 550 ℃ for 1 h did not change dramatically yet the lath in the TMCP+RQ+T treated sample merged together and transformed into polygonal ferrite. At the same time, the sub-structure of grain bainite transformed from lath to cell-shape to refine grains with tempering temperature mounting. Lots of sub-grain boundaries were located within bainite and adjacent bainite grain boundaries were high angle.
关键词:
offshore plate
,
low carbon bainitic steel
,
tempering
,
toughness
,
EBSD
JIAO Duo-tian
,
CAI Qing-wu
,
WU Hui-bin
,
et al
钢铁研究学报(英文版)
By analysing the stepped test pieces with optical microscope, the influence of the Technological parameters including rolling temperature and reduction amount on the Austenitic recrystallization fraction of Nb content of 0.08％ steel deformed in high temperature processing was studied, and the deformed austenite recrystallization figures of the test steel were obtained. The result indicates when the reduction amount is 60%, the critical temperature of complete recrystallization is 1070℃ and the borderline temperature of non recrystallization is 900℃. In contrast with general HSLA steel, the recrystallization and non recrystallization temperatures are respectively 120℃ and 100℃ higher so the steel contenting high Nb has better hot processing performance because Nb has great function of holding back recrystallization.
关键词:
Austenicic Recrystallization;Technological Parameter;high content Nb
