The structure and mechanical properties of 14.8 mm hot-rolled strip coil of X100 pipeline steel (/% : 0.05C

0.25Si

1.97Mn

0.008P

0.002S

0.26Cu

0.36Cr

0.38Ni

0.22Mo

0.03V

0.02Ti

0.09Nb

0.029Als) with finishing rolling at 790-850 °C

after rolling combined ultra-fast cooling and laminar flow cooling with rate 40-60 °C/s cooling to 580 °C and coiling at 380

°C

are tested and studied. Results show that the grain size rating of strip coil is 13.5

the banded structure rating is 0-0.5

the structure is granular bainite + martensite and containing 0.2-0.8 μm martensite/austenite island

the impact energy at -20 °C is 265-277 J and it has better comprehensive mechanical properties to meet the requirement of standard " Technical Specification of Hot Rolled Plate Used for Manufacturing Grade X100 SAWL Pipe f

or Gas Pipeline ".