Test 700 MPa low carbon bainitic steel is melted by a 30 kg vacuum induction furnace

cast to 100 mm x 50 mm flat ingot and rolled to 12 mm plate. Based on CCT curves and analysis on structure of steel at cooling rate 3 ~30 Y/s

the effect of two group microalloying： 0. 06Ti-0. 05Nb and 0. 01Ti-0. 03Nb on structure and mechanical properties of low carbon bainitic steel- % : 0. 059 ~0. 066C

1. 41 ~ 1. 67Mn

0. 30 ~0. 36Si

0. 37 ~0. 48Cu

0. 21 ~0. 24Ni

0. 18 ~ 0. 22Mo

0.000 8 ~0. 002 2Bs

0. 002 6N has been studied. Results show that the strength of steel with 0. 06Ti-0. 05Nb is higher than that of steel with 0. 01Ti-0. 03Nb

but the impact energy at -40 °C of the former

of which the Ti content is higher

is lower than that of the later. The available microalloying Ti-Nb content in 700 MPa low carbon bainitic steel is 0.015% -0. 025%Ti-0. 04% ~0. 05% Nb.