The invention discloses hot-rolled sheet coils of X80
pipe line steel and a manufacturing method thereof. The steel comprises the following chemical components by weight percent: 0.02-0.06% of C, 0.05-0.35% of Si, 1.70-1.90% of Mn, not more than 0.015% of P, not more than 0.004% of S, 0.20-0.35% of Cr, 0.06-0.15% of Mo, 0.06-0.11% of Nb, not more than 0.08% of V, not more than 0.20% of Ni, not more than 0.25% of Cu, 0.005-0.025% of Ti, 0.015-0.045% of Als, 0.001-0.004% of Ca, not more than 0.006% of N and the balance Fe and inevitable impurities. The cold
cracking susceptivity coefficient Pcm is not more than 0.21%. The manufacturing method is characterized in that the
continuous casting slabs are directly subjected to hot charging at 500-850 DEG C and are discharged after being heated to 1150-1250 DEG C, the final rolling temperature of rough rolling is 1030-970 DEG C, the final rolling temperature of finish rolling is 750-850 DEG C, the
compression ratio of finish rolling is more than 60% and the sheet coils are rapidly cooled at the speed of 10-25 DEG C / s by way of
laminar cooling and are coiled at 450-580 DEG C. In the invention, hot charging rolling is adopted, thus improving the
service efficiency of heat, saving energy, shortening the
production cycle, improving the production efficiency and greatly lowering the production cost.