Economical longitudinal submerged arc welding X80 pipeline steel plate and production method

Abstract

The invention discloses an economical longitudinal submerged arc welding X80 pipeline steel plate. The economical longitudinal submerged arc welding X80 pipeline steel plate comprises, by weight percent, 0.035 to 0.055% of C, 0.15 to 0.30% of Si, 0.98 to 1.355 of Mn, not large than 0.012% of P, not larger than 0.0012% of S, not larger than 0.006% of N, 0.055 to 0.065% of Nb, 0.025 to 0.045% of V,0.01 to 0.025% of Ti, 0.10 to 0.25% of Cr, 0.02 to 0.05% of Alt and 0.08 to 0.15% of Mo. The production method comprises the steps of slowing cooling of a casting blank stack not less than 24h; casting blank heating; rough rolling; fine rolling; cooling, tempering; re-straightening, and treating on a cold bed for air cooling to the room temperature. The grade of ant-acid pipeline steel is improved, Rt0.5 is larger than or equal to 580 MPa, Rm is larger than or equal to 650 MPa, A50.8 is larger than or equal to 25%, Rt0.5 / Rm is smaller than or equal to 0.92, at the temperature of -20 DEG C, theV gap KV2 is larger than or equal to 250J, at the temperature of -15 DEG C, DWTT:SA is larger than or equal to 85%, the Vickers hardness HV10 is smaller than or equal to 250, the anti-acid performance and the SSCC resistance performance are excellent, and cracking is avoided.

Description

technical field [0001] The invention relates to a pipeline steel and a production method, in particular to an X80 pipeline steel plate and a production method. Background technique [0002] At present, the world's energy supply is still dominated by oil and natural gas. However, with the H in oil and gas resources 2 With the increase of S gas content and transmission pressure, the pipeline operation is facing the risk of hydrogen-induced corrosion cracking, so it is necessary to use anti-H 2 S corroded pipeline steel. At present, the highest strength of acid-resistant pipeline steel in actual engineering applications at home and abroad is X65MS, and the wall thickness is relatively thin, which cannot meet the engineering requirements of large gas transmission volume and high pressure transmission. Relevant studies have shown that every increase in the level of pipeline steel can reduce the cost of pipeline construction by 5-15%. In order to improve the transmission effici...

AI Technical Summary

Problems solved by technology

Process: Two-stage controlled rolling is used to produce hot-rolled coils. Insufficient performance: its acid resistance only meets the corrosive environment of TM0284-96, B solution, and cannot meet the requirements of high corrosion and high pressure transportation

Disadvantages of composition: and from the composition system of this document, it can be seen that the contents of Ni, Mo and Cu are all above 0.20%, and the cost is high

Although the alloy cost of this patent is low, its strength level is only X70, which cannot meet the requirements of high-pressure transmission

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