The invention relates to a high-strength /
toughness X90 hot-rolled steel strip for spiral submerged arc welded pipes, which is composed of the following components in percentage by weight: 0.03-0.06% of C, 0.25-0.35% of Si, 1.80-2.10% of Mn, at most 0.012% of P, at most 0.002% of S, 0.10-0.25% of Cr, 0.15-0.35% of Mo, 0.06-0.11% of Nb, 0.009-0.02% of Ti and at most 0.003% of N. CEpcm(%)=C+Si / 30+(Cr+Mn+Cu) / 20+Mo / 15+V / 10+Ni / 60+5B<=0.2%. The production method comprises the following steps:
smelting, and carrying out
continuous casting to obtain a blank; heating the
casting blank; carrying out hot rolling; carrying out
laminar cooling; and coiling. When the included angle between the steel
strip test sample direction and the rolling direction is 30 degrees, Rp0.2 is 630-720 MPa, Rm is greater than or equal to 730 MPa, Rp0.2 / Rm is less than or equal to 0.90, the elongation percentage A is greater than or equal to 18%, Agt is greater than or equal to 6%, the -15 DEG C DWTT cross-section shearing rate SA is greater than or equal to 95%, HV10 is less than or equal to 265, the ballistic work single value at -20 DEG C is greater than or equal to 285J, and the ballistic work average value at -20 DEG C is greater than or equal to 355J, thereby completely satisfying the requirements of long distance and high
efficacy for the spiral submerged arc welded
pipe.