X80 pipeline steel plate with thickness larger than or equal to 26.4 mm used in longitudinal submerged arc welding pipe and production method thereof

Abstract

The invention discloses an X80 pipeline steel plate with thickness larger than or equal to 26.4 mm used in a longitudinal submerged arc welding pipe and a production method thereof. The X80 pipeline steel plate comprises the following components in percentage by weight: 0.035-0.055% of C, 0.15-0.30% of Si, 0.25-0.55% of Mn, less than or equal to 0.012% of P, less than or equal to 0.0012% of S, less than or equal to 0.006% of N, 0.065-0.085% of Nb, 0.010-0.025% of Ti, 0.15-0.30% of Cr, 0.02-0.05% of Al, 0.08-0.15% of Mo, 0.1-0.2% of Cu and 0.30-0.50% of Ni. The production method comprises the steps that casting blanks are stacked and slowly cooled for more than 24 h; and the casting blanks are heated, rough rolled, fine rolled, cooled, straightened, tempered, straightened again and then isair cooled to room temperature on a cooling bed. By adopting the production method, the anti-acid performance is good; the yield strength (horizontal) : Rt 0.5 is greater than or equal to 555 MPa; Rmis greater than or equal to 630 MPa; A50.8 is greater than or equal to 25%; a pipe wall is not cracked with increasing conveying pressure; the thickness is greater than or equal to 26.4 mm; structureuniformity is good; Rt0.5 / Rm is less than or equal to 0.91; V-notch impact work KV2 is greater than or equal to 250 J at minus 20 DEG C; the drop weight tear tenacity DWTT:SA is greater than or equalto 85% at minus 15 DEG C; and the Vickers hardness HV10 is less than or equal to 250.

Description

technical field [0001] The invention relates to a pipeline steel and a production method, specifically to an X80 pipeline steel plate and a production method, specifically an X80 pipeline steel plate for a straight seam submerged arc welded pipe with a thickness ≥ 26.4mm 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 in...

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Problems solved by technology

[0006] With the increase of the wall thickness of the steel pipe, the microstructure uniformity will be greatly reduced, the acid resistance performance will be greatly reduced, and the low-temperature drop hammer toughness of the steel plate is more difficult to control. From the analysis of the above documents, it can be seen that none of them can meet the current and future requirements. In terms of oil and gas extraction, with the H 2 S gas content and delivery pressure increase requirements, so it is urgent to develop X80-grade steel plates for LSAW pipes with thick specifications and anti-hydrogen sulfide corrosion

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