The 1900 MPa Ti microaUyed ultra HSLA steel (/% ：0.34C

0.70Si

1.50Mn

0.012P

0.004S

0.08Ti

0. 002 0B

0. 004 ON) is developed by 200 kg vacuum induction furnace and 550 mm slab mill. The results show that with first stage starting and final rolling temperature respectively at 1180 °C and 1030 °C in austenite recrystallization zone

and with second stage starting rolling temperature at 920 ~ 950 °C and final rolling temperature at 850 ~ 890 °C in austenite nonrecrystallization zone

then quenching at (900 ± 10)°C and tempering at 200 〜230

°C

the plate precipitated phase is (Ti

Mo)C

the grain size rating is 10

the structure is tempered martensite

with the mechanical properties are Rm 1930 〜1985 MPa

A 10% ~ 12.5%

-40 T K

v2

200 ~ 230 J.