The effect of cooling rate (0. 5 ~35℃/s) and strain (0. 3 ~ 0. 6) on structure of X100 pipeline steel (%: 0.06C
0. 23Si
1.90Mn
0. 005P
0.0003S
0. 28 Mo
0. 25 Ni
0. 23 Cr
0. 05 Nb
0.02Ti
0. 20Cu
0. 025Al) has been studied by thermo-simulation test and the static and dynamic continuous cooling transformation (CCT) curves of the steel are obtained. Results show that complete bainite structure could be got at cooling rate of 5℃/s from un-deformed austenite; with deforming
the initial transformation temperature of austenite increases
and with increasing hot strain
the acicular ferrite transformation region enlarges while the lath bainite transformation region shrinks.