Economical X70 petroleum and gas pipeline steel and production method thereof

The invention relates to economical X70 petroleum and gas pipeline steel, which comprises the following components in percentage by weight: 0.10-0.14% of C, 0.15-0.35% of Si, 1.25-1.50% of Mn, no more than 0.015% of P, no more than 0.0020% of S, 0.16-0.25% of Cr, 0.025-0.045% of Nb, 0.030-0.050% of V, 0.008-0.020% of Ti, 0.020-0.050% of Al, and no more than 0.008% of N; the production method comprises the steps of: smelting and pouring into a blank; heating a case blank; performing rough rolling on a wide-heavy plate mill; performing finish rolling on the wide-heavy plate mill by two stages; cooling; straightening. The price is reduced by no less than 5% compared with the existing price, and for a steel plate, the yield strength (R ) is more than or equal to 485MPa, the tensile strength (R ) is more than or equal to 570MPa, the yielding-to-tensile ratio (R /R ) is less than or equal to 0.88, the elongation percentage (A ) is more than or equal to 24%, -20DEG C KV2 is more than or equal to 200J, -15DEG C WTTSA is more than or equal to 85%.